CA2064192A1 - Wrapping apparatus and method therefor - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A wrapping apparatus which comprises:
means for supplying a band-like member, means for stretching the band-like member in at least lateral direction thereof, the lateral stretch means comprising a unit for running the band-like member to spread out the member so that it forms a sector (an unfolded fan) and a unit for detachably gripping the regions (or margins) of the band-like member respectively near the opposite widthwise ends thereof so that they are detachable from the running unit, and means for winding the stretched band-like member around an article for the wrapping thereof.
As one embodiment of the present invention, a method for wrapping an article with said wrapping apparatus is disclosed.

Description

?. ~ 2 TITLE OF THE INVENTION
APPAR~TUS FOR WRAPPIN~ AND METl30D TilEREFOR

BACKGROUND OF THE INVENTION
1. Field o-f -the Invention The present invention relates to an apparatus for wrapping an article with a stretch film and a method therefor.

2. Description of the Related Art As a conventional method of wrapping an ar-ticle, there was used a method -for wrapping an article with a shrinkable film, which comprises heating the article through a heating tunnel or the like and then wrapping the article by a shrinking force caused by heating~
This method required a heating means and thus raised a problem that a large heating tunnel was required for a large article, resulting in incurring high film and system costs.
In place of this method, a method for wrapping called pallet or stretch wrapping has been known and used in recent years. This method is the one ~or winding a film, while stretching it, around articles, or grass or a roll of paper stacked on a pallet, thereby wrapping the ar-ticle. In recent years, this wrapping method has been developed and contributed to the rationalization of transportation, s-torage.

wrapping of articles. A wrapping method now in prevalent use is a method comprising longitudinally - 2 ~

stretch:ing ~ film with a winding tension exerted on an article and then wrapping -the article with a shrinking force of the stretched -~ilm. There is also provided another method for wrapping an art:icle comprising longitudinally stretching a film and then wrapping the artic]e with an appropriate winding tension (Japanese Patent Publication Nos. Sho 59-52087 and 61-27254). A
stretch wrapping (pallet wrapping) system does not require a heating means such as a heating tunnel.
Since this system requires a less expensive apparatus cost, i5 suitable for wrapping a large article and has thus come to be widely used in recent years.
According to these conventional wrapping methods, in order to wind a film around the entire side surfaces of' an article, the film must be wound to form multiple plies while they partially overlap each other because the film has a width which is smaller than the height of the article. When a normal 500-mm wide film is used, the -film must be wound in 10-15 plies around an article having a height of 1 to 1.5 meters.

In order to reduce the number o-f turns or plies, a -film having a larger width is considered to be used.
However, a wide roll film is inconvenient for handling during its transportation and -for mounting it on a wrapping apparatus. It is difficult to uniformly wind, in a roll-like manner, a wide thin (about 251Jm) film with one or both surfaces being coated with an 5 ~ ~J
adheslve. It is also dit`ficult to ~anuracture a wide film .
In order to generally reduce the aMount of a film used, a -fil~ having a -thickness as small as possible is desirably manueactured to reduce the wrapping cost. A
-film tends to be very stretchable and is coated with an adhesivè. It is, there-~ore, difficult to manufacture a film having a thickness of 10 um or less whe-ther it is large or small in width.
~- ~ lateral stretch system generally used in the ~iIm industry is considered to be used to stretch a film having a small width laterally to obtain a wide film. Any lateral stretch system, however, is not always suitable -for pallet wrapping. For example, as lateral stretch apparatuses generally used in the film industry, a tenter apparatus and a tubular biaxial stretch apparatus are availabe. These apparatuses are expensive, require a large installation ~loor area, and are not practical for pallet wrapping needing simplicity and convenience. In a tubular biaxial stretch system, produc-tion lines must be stopped every wrapping cycle, and it i5, therefore, di-fficult to maintain the internal pressure o-f a tube constant. It is also difficult to cut a soft, adhesive tubular -film and develop it into a flat sheet. The tubular biaxial stretch system requires a certain running distance to develop the tube into a sheet and results in a bulky apparatus.

A variety o-f other easy-to-harldle :Lateral stretch apparatuses :in addition to the above apparatuses are proposed in the film industry. 0-f these apparatuses so proposed, hardly any ones are in practical use because it is di-f-ficult -for them to carry out uniform stre-tching di-fficult. Slight stretch irregularity of a biaxial stretch -film may cause a winding strain. A
film having a winding strain results in a de~ective product.
A known easy-to-handle llateral stretch apparatus is a lateral stretch apparatus using a pair of rollers each having a roll surface constituted by a combination of protrusions and recessed grooves (Japanese Patent Publication No. Sho 46-11599 and others). Accoriding to this apparatus, a lateral stretch magnification is small, and stretching is per-formed at a maximum magni-fication o~ about 1.5 times. In particular, if a roll film to be used in pallet wrapping is stretched at about room ~temperature, a large shrinking stress will be caused. For this reason, the roll film will immediately shrink a-fter stretched, and, ~thereeore, an effect o-~ lateral stretching is low. Even if the film is stretched laterally, the film is not stretched in the widthwise direction; there is therefore needed an independent step of stretching the -fllm in the widthwise direction.
Another conventional easy-to-handle stretch apparatus is a s-tretch appara-tus utilixing pulleys (BP

- 5 ~

849,436). The present inventors have proposed a variety of pulley type stretch apparatuses (e.g., Japanese Patent Publication Nos. Sho 61-55456 and 57-30368). Stlll another conventional easy-to-handle stretch apparatus is exemplified by a stretch apparatus having a large number o-f grippers (Japanese Pa-tent Publication No. Sho 63-44049) and needle-like pins planted in the periphery of a rotary disc. Such a conventional rotary disc type lateral stretch apparatus cannot be applied to pallet wrapping because this apparatus allows a laterally stretched -film to run horizontally in its longitudinal direction.
The conventional wrapping methods described above are excellent in air-tightness because articles are wrpped with -films. For -this reason, these wrapping methods are often not suitable for articles such as vegetables and -fruits in the fields requiring air or moisture permeabili-ty and the fields requiring prevention o~ dew condensation. As a manufacturing problem, the film width is reduced after longitudinal or lateral stretching, thereby reducing wrapping ef-ficiency. In particular, in lateral stretching, a remarkable widthwise shrinkage occurs after the film is stretched laterally.
There is also available a conventional method using a net-like material as an air-permeable wrapping material and stretching this material along its longitudinal direction. This me-thod, however, results U ~J
in higher cost than a method using a -fi:Lm. In addition, when an article is large in size, a greater number of t~lrns is undesirably needed for wrapping the article because a net width is small. Therefore, the method using the net-like material is much less practical due to the consumption of a large amount of the material and a long wrapping -time.

SUMMARY OF THE INVENTION

lV It is an object o~ the present invention to provide a simple, compact apparatus for wrapping and a method therefor.
It is another object of the present invention to pro~ide an apparatus for wrapping and a method therefor, allowing a less amount of a film to be used for wrapping and a shorter time to be taken therefor.
It is still another object o-f the present invention to provide an apparatus for wrapping and a method therefor, capable of reducing widthwise shrinkage which has posed a serious problem in the stretch step of a conventional process when an air-, moisture-permeable and dew condensation-preventing wrapping is intended.
In order to achieve the above objects of the present invention, there is provided a wrapping apparatus for stretching a band~ e member and winding the stretched band-like member around an article, which comprises means for supplying a band-like member, a means for stretching the band-like member a-t least in the lateral direction thereo-f. the lateral s-tretch means being provided with means -~or running -the band-l:ike member while widening the member to -form a sector or spread:ing it out like an unfolded -fan and means -for gripping regions (margins) respectively near opposite widthwise ends o-~ the band-like member in such a manner that the regions are detachable from the running means, and means ~or winding the band-like member around the article.
Preferably, the running means comprises: a first running portion moving along a first endless route which have a first forward path used for running o-f the region near one of the opposite widthwise ends of the band-like member and a ~irst backward path not used -~or running o~
the band-like member; and a second running portion moving along a second endless route which have a second forward path used for running of the region near the other one of the opposite widthwise end porions of the band-like member, the widthwise space between the second ~orward path and the first forward path being gradually increased as the band-like member runs, and a second backward path not used -for running o-f the band-like member.
For example, the running unit comprises a first rotary disc having the first running porion formed on the peripheral portion of the disc and a second rotary disc having the second running portion ~ormed on the periphery of the second disc, and the gripping means - 8 ~ J ~J

comprises a -~irst gripping member for detachably f'ixing the region of one widthwise end of the band-like member to the -first running portion, and a second gripping member for detachably -fixing the region O-r the other widthwise end of the band-like member to the second running porion.
Preferably, this wrapping apparatus further comprises ~uide means -~or guiding the band-like member gripped by the gripping means. For example, the guide means comprises a guide member -for guiding the band-like member so that a difference in running length o-f the band-like member is reduced in the widthwise direction.
For example, the guide member comprises a first guide portion for guiding a central portion of the band-like member and a second guide portion -for guiding p~rions between the central portion of the band-like member and the respective opposite widthwise ends thereof. The wrapping apparatus may have means -for heating the band-like member.
~ III addition, the wrapping apparatus may have longitudinal stretch means for stretching -the band-like member in the longitudinal direction thereof. The longitudinal stretch means comprises a longitudinal post-stretch mechanism for longitudinally stretching the band-like member after the band-like member is laterally stretched by the lateral stretch means. Pre-ferably, the longitudinal post-stretch mechanism comprises a stretch member for longitudinally stretching the laterally gJ~ ~
stretched band-like rnember releasecl from the running means whlle the amount of widthwise shr:lnkage caused by a widthwise shrinking force of the laterally stretched band-like member is small. The longitudinal post-stretch mechanism comprises means -for longitudinally stretching the band-like member at a winding speed of the winding means, which is made higher than a band-like member -feeding speed o-f the lateral stretch means.

The longitudinal stretch means comprises a longitudinal pre-stretch mechanism -for longitudinally stretching the barld-li~e member before the band-like member is laterally stretched by the lateral stretch means. The longitudinal pre-stretch mechanism comprises means for longitudinal stretching the band-li~e member, for example, at a band-like member introducing speed of the la~teral stretch means, which is made higher than the band-like member supply speed of the supplying means.
Pre-ferably this wrapping apparatus compr;ses means for regulating a tension for winding the band-like member around the ar-ticle. The winding means comprises means for rotating the article to wind the band-like member around the article. The rotating means comprises a turntable on which an article placing region having a predetermined height is defined. The lateral stretch means comprises means -~or stretching the band-like member in the lateral direction so that the band-like member has a larger width than the heigh-t of the article placing region. For example, the rotating means - 1.0 -comprises means ~or rotating the ar-ticle about an axis except ~or a vertical axis.
Preferably, this wrapping apparatus further comprises means for preventing widthwise shrirlkage of the laterally stretched band-like member. Pre*erably, this wrapp:ing apparatus -~urther comprises means -for changing a stretch magni-fication.
According to the present invention, there is also provided a wrapping apparatus for stretching a band-like member and winding the stretched band-like member around an article, comprising means for supplying the band-like member, means -for stretching the band-like member in at least one of longitudinal and lateral directions, means for winding the stretched band-like member around the article, and hole forming means forming holes in the band-like member before the band-like member is wound around the article.
Preferably, this wrapping apparatus further comprises means for heating the hole -forming means ZO before the winding means winds the band-like member around the article. For example, the hole ~orming means comprises means for forming slits parallel to t~le stretch direction o-f the stretch means. Preferably, this wrapping apparatus ~urther comprises width increasing means for increasing the width of the band-like member stretched by the s*retch means and perforated by the hole forming means.

A wrapping method according to the present invention is characteri~ed by compris:ing the steps o-f supplying a band-like member, stretching the band-like member to increase an air-permeability density o-f the band-like member, and winding the stretched band-like member around an article.
Pre-~erably, this wrapping method further has a step of increasing -the width o- the stretched band-like member. This band-like member may be a per-forated band-like member or a band-like member per-~orable by stretching.
In addition, there is provided a wrapping method o-f winding a band-like member around an article, characterized by comprising the steps of stretching the band-like member having a width smaller than that of the article in at least the lateral direction of the member to have a width larger than that o-f the article, and winding the stretched band-like member around the article such that the band-like member covers all side 2~ sur-faces o-f the article by one turn, and one side edge portion o-f the band-like member extends from at least one end portion o-f the article.

PRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a side view showing a wrapping apparatus according to a first embodiment O-r the present invention;

Fig. 2 is a plan view showing the apparatus shown in Fig. ~;
Fig. 3 is a side view showing a gripper type stretch apparatus;
Fig. 4 is a perspective view o-f a pulley type lateral stretch apparatus;
Figs. 5A to 5C are views showing roll films having di-f-ferent stripe patterns -for causing dif-ferences in -film thicknesses, respectively;
Figs. 6 to 10 are views showing films used as roll films, respectively;
Figs. llA and llB are views showing nets used as original rolls, and Fig. 12 is a view sowing an unwoven fabric used as a roll;
Fig. 13 is a side view showing a wrapping apparatus according to a second embodiment o~ the present invention;
Fig. 14 is a plan view showing the apparatus shown in Fig. 13;
Fig. 15 is an enlarged view showing a longitudinal stretch urlit in the apparatus shown in Fig. 13;
Fig. 16 is a side view showing a mechanism for changing a lateral stretch magni-fication;
Fig. 17 is a view showing another mechanism for changing a lateral stretch magnification;
Figs. 18A to 18C are views showing di-fferent types o~ stretch pulleys, respectively:

v Fig. 19 is a sectiona:L v:iew showing a gripper type lateral s-tretch rotary disc;
Fig. 20 is a view showing a structure in whicdh a large number of needle-like pins planted in -the peripheral porion Or the lateral stretch rotary disc;
Fig. 21 is a view showing a barrel roll as a guide turn roll;
Fig. 22 i.5 a view showing a structure in which a large number of guide rolls are mounted on the turn rolls;
Fig. 23 is a view showing a structure in which lateral stretch rotary discs having di-~-ferent diameters are asymmetrically disposed;
Fig. 24 is a view showing a structure in which ~rustoconical widthwise shrinkage preventive devices are arranged at both ends o-f the outlet o-f a lateral stretch unit;
Fig. 25A is a view a structure in which frustoconical widthwise shrinkage preventive units are mounted on an arcuated bar, and Fig. 25B is a sectional view of each frustoconical widthwise shrinkage preventive unit;
Figs. 26A and 26B are views showing a cylindrical wrapping apparatus;
Fig. 27 is a side view showing a wrapping apparatus according to a third embodiment of the present invention;

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~'ig. 28 is a plan view of the apparatus shown in F'ig. 27;
Fig. 29 is a side view showing a wrapping apparatus accordlng to a fourth embodiment o~ the present invention;
Fig. 30 is a plan view of the apparatus shown in Fig. 29;
Fig. 31 is a side view showing a wrapping apparatus according to a ~ifth embodiment o-f the present invention;
Fig. 32 is a plan view o~ the apparatus shown in Fig. 31;
Fig. 33 is a perspective view showing a wrapping apparatus according to a sixth embodiment of the present invention;
Figs. 34A and 34B are schematic views showing groove roll type lateral stretch apparatus;
Figs. 35 and 36 are schematic views showing a pin roll;
Fig. 37 is a sectional view a cutting blade slitter;
Fig. 38 is a side view showing a wrapping apparatus according to a seventh embodiment of the present invention;
Fig. 39 is a plan view o-~ the apparatus shown in Fig.38;

l~ig. ~0 is a perspective view showing a wrapping apparatus according to an eigh-th embodiment of the present invention;
Fig. 41 is a side view showing a wrapping apparatus according to a ninth embodiment o-f the present invent:ion; and Fig. 42 is a plan ~iew o-f the apparatus shown in Fig. 41.

DETAILED DESC~IPTIO_ ~F T~IE PBEFERR~D EMBODIMENTS
The first embodimen-t and its modi-fications of the present invention will be described with re~erence to Figs. 1 and 2. Figs. 1 and 2 are a side ~iew and a plan view, respectively, showing a wrapping system using a portable pin tenter lateral stretch apparatus. An original roll film 1 in -the form of a roll stands upright and is placed on a table 2. The width of the original roll film 1 is smaller than the height of an article 11. Upper and lower chains 3a and 3b are guided by chain wheels 4a-1, 4a-2,.... A large number of needle-like pins 5a-1, 5a-2, 5a-3,.... (to be briefly referred to as pins 5 hereinafter) extend on the chains 3a and 3b. These components constitute a pin tenter lateral stretch apparatus. Both side edge portions of the original roll film 1 are hooked and gripped by the pins5. The original roll film 1 runs along a spreading path defined between the chains 3a and 3b to ~tretch ~he original roll film l laterally, i.~., vertically in Fig. l. The original roll film 1 is stretched to have a width larger than the height of the article. When the original roll film 1 is stretched at a predetermined magnification ~preferably, an apparatus stretch magnification is 2.2 times or more), the paths defined by the chains 3a and 3b become parallel to each other. At a portion where the paths of the chains 3a-and 3b are parallel to each other, polymer molecules of the stretched original roll film l are aligned to each other. ~he original roll ~ilm l is separa~ed from the pins 5 at the terminal end of the tenter and serves as a laterally stretched film 6. The width of the laterally stretched film 6 i8 larger than the height of the article.
Longitudinal s~retch rolls 7a and 7b are arranged next to the pin tenter unit. A dancer roll 8 is arranged next to the longitudinal stretch rolls 7a and 7b. An article 11 placed on a turntable 10 is placed next to the dancer roll 8~ Upon rotation of the turn~able lO, the article 11 is rota~ed. By rotation o the turntable 10 by a plurality of revolutions, almost all the side surfaces of the article lO are wrapped with a laterally and longitudinally stretched film 90 The stretched film 9 is wound around all the side surfaces o the article 11 so that one side edge portion of the film 9 extends from the upper or lower - 17 ~

end of the article 11. Reference numeral 9a denotes one side edge of the film 9 which extends from the upper or lower end of the article 11. The turntable 10 is kept rotated at a constant rotation speed by a motor 12 or constant -tension by a torque motor.
This embodiment is characterized in that the film runs upright and is extended laterally, i.e., vertically in ~ig. 1. The lateral stretch apparatus of this embodiment is also characterized in that both side edge portions of the original roll film are gripped and the film is stretched along the spread path formed by the gripper portions. ~ateral stretching by gripping both the side edge poxtions can assure a large lateral stretch magnifica~ion and can obtai~ a prede~ermined lateral stretch magnification. Therefore, this lateral stretch apparatus is suitable as a lateral stretch means for stre~ching a film to have a width larger than the heigh~ of the article. A typical example of the lateral stre~ch apparatu~ is a tenter type lateral s~retch appara~us used in film industries. A tenter type lateral s~retch appara~us used to biaxially stretch a polypropylene or polyester film can be used as a compact, portable apparatus when it is used in this embodiment because a stretch speed may be low and slight stre~ch variations are allowed. In addition, this apparatus does not require heat. As another conventional stretch means of this embodiment, a pulley ~ 3~ JI ~

stre~ch apparatus disclosed in Japanese Patent Publication Nos. Sho 57-30368 and 61-55456 as the prior-art inventions of the present inventors.
After the laterally stretched film passes the dancer roll, the film is wound around the article rotated on the turntable by a winding tension of the article while the film is longitudinally stretched, thereby wrapping the side surfaces of the article.
According to this method, since the length of longitudinal stretching is large~ widthwise shxinkage of the laterally stretched film is large, but the re~ultant apparatus i8 easy to handle.
Still another characteristic feature of this embodiment is a combination of the lateral stretch apparatus, the longitudinal stretch apparatus, and the turntable for supporting and rotating the article.
The width of the pallet wrapping film can be increased in this embodiment. The width of the film can be increased to a width larger than the height of the article, so that almost all the sid~ surfaces of the article can be wrapped with the film by one turn.
In this case, "wrapping of almost all the side surfaces of the article by one turn" indicates that at least one of the turns satisfies wrapping of almost all the side surfaces of the article. In particular, it is important to partially wind the axticle with the film, v ~
~nd all the side surfaces of the articl~ need not be wound by the first turn.
In general biaxial stretch apparatus, and particularly, a portable biaxial stretch apparatus, longitudinal stretching is performed first, and then lateral stretching is performed because the longitudinal stretch apparatus can have a small width.
In this embodiment, however, longi~udinal stretching is performed after lateral stretching because a force for holding an article upon winding of the articles on the pallet with the film is large and article misalignment rarely occurs according to experimental results.
However, after slight longitudinal stretching is performed, lateral stretching and then further longitudinal stretching may be performed becau~e a to~al longitudinal stxetch magnification can be advantageously increased. In this case, the first longitudinal stretch magni~ication is preferably 100%
or less.
In this embodiment, a lateral stretch ~0 magnification is at lea~t twice, and preferably 2.S
times or more because the width of the original roll film is increased at a low stretch magnification. The width of a pallet wrapping stretch film i~ gener~lly ~00 mm. It is inconvenient to cause one operator to wrap an article with a film ha~ring a width larger than 500 mm. The height of an article generally falls within the ran~e of about 1 -to about 1.5 ~n. After lateral stretching is completed, the film must be stretched at a considexably high magnification when incapabili~y of maintaining a cons~ant width and widthwise con~raction are ~aken into consideration.
The width of an original roll cannot be unlimitedly increased due to manufacturin~ limitations of original rolls. Therefore, the later~l stretch magnification preferably falls within ~he range of at least twice, and preferably 2.5 times or more in accordance with economical and operational viewpoints.
When original stretch films are measuxed by a tensile test of JIS Z1702 (wrapping polyethylene film), each of the longitudinal and lateral stretch magnifications is preferably 300~ or more. When ~he magnification preferably exceeds 400~, a film is apparently e~cellent in biaxial stretching. In addition, when a strength retention ra~io of a 100%
stretched film in the longitudinal direction i 50~ or more, and preerably 60% or more, a stable state of a pallet-wrapped article can be obtained.
If the above requirements are satisfied, examples of a polymer used for this film are LLDPE (Linear Low-Density Polyethylene), LDPE (Low-~ensi~y Polyethylene), BVA (Ethylene-Vinyl Acetate Copolymer), polybutadiene, polyvinyl chloride, and poly~inylidene chloride. These polymers are blended or formed into a 3~

multi-layered structure. An adhesive agent such as a liquid rubber (e.g., polybutene) and a petroleum resin is blended and applied to ~he surface of a polymer layer.
According to the first embodiment, the following effects which were no~ ob~ained in the conventional techniques can be o~tained.
(1) Although the width of an original roll can be small, a film having a large width may be used to perform pallet wrapping. The original roll having a small width can be used to provide the following effects.
A film can easily ~e transported to a parallel wrapping machine. Although ~he original roll mu6t be se~ upright, it is easy for each operator to mount it because it has a small width. It is difficult to form an adhesive original roll having a uniform thickness and a large width. As in this embodiment, however, it easy to form an original roll having a small width.
(2) Biaxial stretching is performed to obtain a wide original roll from a narrow original roll. Unlike in a conventional technique, a mechanism for ~ertically reciprocating (traverse) the position of the original roll position need not be used. In addition, the width of an original roll can be stretched to have a width enough to wrap all side surfaces of an article by one turn.

_ 2~ -~,~f~ J

Since each original roll is stretched ko have a smaller thickness and wound ar~und an article~ the original roll can be saved, iOe., the amount of film used can be reduced. In a conventional method of performing only longitudinal stre~ching, since the original roll film must be vertically reciprocated, ths numb~r of turns is inevitably increased. When a 20-~m thick film was longitudinally stretched twice and the stretched film was wound 15 times around an article ha~ing one side of 1,600 mml a ~otal amount of film used was 480 cm3 (= ~o cm (wi~th) x 0.02 cm (thickness) x 4 sides x 1,600 cm x 15 turns/(stretching twice)).
However, this film can be al60 longi~udinally stretched twice by biaxial stretch and the stretched film can be wound around the ar~icle four times. Therefore, even if a film having a thickness of 40 ~m is used, a total amount of film used is 256 cm3 (= 50 cm (width) x 0.004 cm (thickness) x 4 sides x 160 cm x 4 times (s~retching twice)), which can be a half of the amoun~ of ~ilm used in the con~entional technique.

~ film having a small width must be wound by forming overlapping portions. Dust tends to be collected on khe overlapping portions and moisture tends to permeate through the overlapping portions.
These problems may be solvsd if the above drawbacks are eliminated withou~ wrapping an article with a wide film.

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Since biaxial stretching is performed, biaxial shrinkage stresses (i.e., shrinkage stresses in the widthwise and longitudinal directions of the film) of the film act on an article wrapped with a film having a width larger than the height of the article. Since bo~h side edges of the ilm extend from the upper and lower portions of the ar~icle, the widthwise shrinkage foxces of the film act from its upper and lower ends toward iks center, thereby applying an appropriate binding force on the article. A binding force is often excessively applied to an article by onl~ uniaxial str ~ching. According ~o this embodiment, however, even if a ~ilm is longi~udinally wrapped so as to prevent damags of the article, strong binding can be performed by utilizing ~ertical (widthwise) shrin~age stresses ac~ing on the article. When biaxially stretched film having a small width is helically wound around an article, ~he widthwise shrinkage stress is not applied in wrapping of the article.
(3) Since the lateral stretch apparatus for gripping both side edges of a film and laterally stretching the film, a stretch magnification is set high, and optimal stretching can be performed.
By variably changing the lateral stretch magnification, products having different widths can be advantageously manufactured from an original roll having a given width. By variably changing a stretch - 2~ ~

magnification, film shrinkage forces (article binding f~rces) can he variably changed to obtain an optimal wrapping form of the article.

(4) In a normal film, a thin portion is localized at a few positions such as neckingO In ~his embodiment, by using an original roll film having a longitudinal ~hickness pattern ha~ing longitudinal stripes having a thickness different from that of the remaining portion, thin and ~hick portions of the stretched film can be almost uniformly, distributed in the widthwise direc~ion~ In addition, tearing can stop at this stripe, thuæ providing physical advantages.
Table 1 shows experime~al r~sults of various types of films by using an apparatus of the fixst embodiment. An elongation of the ~ilm was measured by a tensile test of JIS Z1702. A strength retention ratio is de~ined as a remaining frac~ion o the ~otal strangth when a film is stretched ~o a 100~ elongation and thi~ stretched state is maintained for 30 minutes.
The thickness of each original roll film was 40 ~m.
Stretch property mea~urement was performed by using the apparatus shown in Fig. 1, except that a lateral stretch apparatus portion was a pulley type lateral stretch apparatus shown in Fig. 4 (to be described later). Experiments were conducted using a pulley diameter of l,000 mm and variously changing the lateral stretch magnification. The longitudinal stretch _ 25 -magnification by a stretch roll was fixed to twice.
The biaxial stretch properties were examined by experiments for winding each film by four turns at a turn~able speed of 8 rpm. In Table 1, a mark o represents that a film could be stretched at a magnification of 4.5 times, a mark o represents that a film could be stretched at a magnification of 3.5 times, a mark ~ represents that a film could be stretched at a magnification of 2.5 times ox more, and a mark x represents that a film was not stretched at a magnification of 2.5 times. At a lateral stretch magnification of 2.~ times, a substantial stretch magnification as the overall width of the film is about 2.2 times. In high elongation measurements, an original roll film having an elongation of 300% or less has poor biaxial stretch properties. Stable ~tretching can be apparent performed at ~n elongation of 400~ or more.
Forty heavy bags (overall weight- 1 t) each containing polypropylene pellets having an overall weight of 25 kg on a pallet were wrapped. These bags were wrapped by winding a film four times. A lateral stretch magnification of the film was set to 2.5 to 3.~
times, and a longitudinal stretch magnification was set to twice. The wrapped articles were left still for 3 days. The wrapped articles were inclined together with the pallet to check wrapping stability. The articles ~ ~ ~ fl ~_ r,J ~
were misaligned at an inclination angle of 45, as i~dicated by a mark x, and the articles were not misaligned at an inclination angle of almost 90, as indicated by a mark ~. Other marks represent misalignment values between the 0 inclination and the 90 inclination. It is apparent from Tabls 1 that a film having a strength retention ratio of 50% or less has poor wrapping stability. It is apparent that high stability can be achieved at a strength retention ratio of 60% or more.

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X O X t- O D 1~ O O ~~.
_ - 2~ -Original roll films used in this embodiment must have specific physical properties. More specifically, each original roll film must have a stretch property and must comprise a stretch film not susceptible to misalignment of wrapped articles. The following results are obtained from the above experimental results.
The thickness of the original roll film preferably falls within the range of 15 ~m to 120 ~m and more preferably 15 ~m to 80 ~m. When a film having a thickness of 25 ~m or less is biaxially stretched, the film may be torn. When the thickness of a film is 15 ~m or less, tearing of the film is undesirably increased. Therefore, these film thicknesses are not suitable for pallet wrapping reguiring stable wrapping.
In normal wrapping having a film thickness of 80 ~m or less, if particularly rigid wrapping is required and unless an original roll film having a thickness of 120 ~m or le~s is used, a winding tension is undesirably increased to damage the article. In stretching using a thick film, a stretch ~ension is increased to requirè a heating unit or increase a mechanical strength, thereby losing an advantage as an easy-to-handle stretch apparatus. Use of a thick film causes an increase in wrapping cost, resulting in an impractical application.
In the general manufacture using a commercially available wrapping film in biaxial stretching, the ~ 2 ~ 2 thickness of the original roll film preferably exceeds 100 ~Im and is often be about 200 ~m.
The table 2 may be braked to apply a supply tension on the original roll film 1 to perform longitudinal stretching prior to lateral stretching of the film 1. This longitudinal stretching can be performed such tha~ a supply speed of the original roll film 1 is set ~o be higher than ~hat of the infeed speed of the chains 3a and 3b. ~ore spscifically, thé
speed o~ the motor 61 for dri~ing the table 2 is set low, and the speed of motors 62a and 62b for driving the chains 3a and 3b are set high, so that the supply speed of the origin~l roll film l is set higher than the infeed speed of the chains 3a and 3b. After the film l is longitudinally stretched, it is hooked by thè

pins 5 formed on the chains 3a and 3b and is then laterally stretched. The laterally stretched film 6 may be longitudinally stretched by the longitudinal stretch rolls 7a and 7b. However, since the film is already stretched in the longitudinal direction, longitudinal stretching by the rolls 7a and 7b may be omitted.
The film 9 passes through the dancer roll 8 (this may be omitted~ and is wound around the rotating article 11 while the film is being longitudinally stretched by a tension caused by the dancer roll and the winding force on the turntable. More specifically, the film 1 is longitudinally st etched and wound in accordance with a difference between the supply speed of the film 1 from the dancer roller 8 and the winding speed of the film 1 wound around the article 11.
Up to the process before the lateral stretch apparatus, the original roll film 1 need not he almost longitudinally stretched~ and the longitudinal stretch roll arranged upon lateral stretching may be omitted.
In this case, as in the above modification, the film 1 is wound around the article while the film 1 is longitudinally stre~ched by a winding tension of the article 11. More specifically, ~he outfeed speed of the laterally stretched film from the chains 3a and 3b is set lower than a winding speed of the film around the axticle. ~or thi~ purpose, the speed of the mo~ors 62a and 62b is set low, and the speed of the motor 12 is set high.
In $he lateral stretch apparatus, longitudinal stretching of the original r~ll film 1 is not almost pexformed. After lateral stretching may be performed, the ~ilm may be longitudinally stretched by the longitudinal stretch rolls 7a and 7b, the film may be wound around the article 11 with an optimal wrapping tension. This minimizes widthwise shrinkage of the film.
The film 1 may be longitudinally stretched between the lateral stretch apparatus and the roll 7a. This - 31 - ~ 92 longitu~inal stretching may be added after the longitudinal stretching in sach modification described above or may be performed in place of the longitudinal stretching of each modification.
An apparatus shown in Fig. 3 may be used as a lateral stretch apparatus. This lateral stretch apparatus includes pantographs ~4a and 14b running ~n rails 13a and 13b. Each pantograph has a large number of grippers (or grips) 15. The yrippers 15 grip both side èdge portions of a film 16 and laterally stretch the film 16. In Fig. 3, since the pantographs 14a and 14b are used, stretching operations in ~he lateral and longitudinal directions can be simultaneously performed.
A pulley type lateral stretch apparatus shown in Fig. 4 may be used as a lateral stretch apparatus. A

pair of upper and lower lateral stretch pulleys 17a and 17b are arranged to form an inverted V-shaped spread path. An original roll film 19 is gripped by endless belts 18a and 18b. The original roll film 19 can be stretched by a path having a length corresponding to a half of the circumferential leng~h of each of the pulleys 17a and 17b.
Examples of the article used in wrapping in this embodiment are a large number of cardboard boxes placed on a pallet, a set of articles such as heavy bags, - 3~ ~
2 ~
s~acked grass, and a roll of p~per. Any one of the articles is placed on a turntable.
The shape of an article around which a film is wound is rectangular as in a set of cardboard boxes and a set of heavy bags when viewed from the top. While a film is being wound around a rectangular parallelepip~d article, the turntable is rotated at a constant speed.
However, the speed at which the film i5 wound around an corner of the article is different from that at which the film is wound around a side surface of the article.

A stretch line may follow a change in running speed of the film. After stretching on the longitudinal stret~h line is comple~ed, a dancer roll may be disposed in front of the turntable to absorb a difference in speeds at the corner and the side ~urface of the article.
When the size of an article is increased or a wrapping speed is increased, a plurality of longitudinal stretch apparatuseæ and a plurality of lateral stretch apparakuses may be arranged to p~r~orm stretch a film by a multi-stage system.
In the first embodiment, the film is used as ~n original roll. However, other original roll~ shown in ~igs. 5A to ll may be used.
A film having several longitudinal stripes as thick or thin portions to several hundreds of longitudinal stripes within the width of the original roll may be used as an original roll film. Figs. 5A, 5s, and SC show original roll fil~ls 20 having stripes ~1-1, 21-2,..., 22-1, 22 2,..., and 23-1, 23-2,....
causing a difference in thickness in the longitudinal direction. The stripes are waved, hatched, or crosshatched to prevent them from serving as skeletons when the corresponding films are rolled. The hatched and crosshatched stripes in Figs. 5B and 5C can be used when if a longitudinal co~ponent is present al~hough it is close to a lateral component.
By using such a film, the thick portion is not subjected to lateral stretching and ~erves as a stretch film having re.gular longitudinal stxipes. That is, a film which is partially stretched as in a necked film can be obtained. The stre-tched thin portions can be almost uniformly loca~ed in the widthwise direction of the film. These stripes prevent~ lateral tearing of the film during lateral stretching or in a wrapped film, thereby con~ribuking to manufacturing stability and impr~vement of product quality.
In a film having longitudinal stripes, the stripes ~ ser~es as a skeleton to obtain an original roll and may not be a uniform roll. In this case, by using a rotary die during film formation, a winding machine is reciprocated in the right-and-left direction to prevent formation of a skeleton by the stripes. The thickness of the stripe portion i5 laxger than ~everal ~ or several tens of % of the thickness of a normal portion.

- 3~ -When a stripe portion is -thick, the width of the stripe is preferably small. ~hen the strip portion is thin, t~is portion is preferentially stretched, it preferably has a given width.
Fig. 6 shows a perforated film 40 having holes 42.
The size and number o~ holes 42 are determined in consideration of air permeability for a wrapping purpose, a retained tension of a web on an article, and the like. Each hole 42 may be constituted by a slit.
In the lateral stretch apparatuses shown in Figs. 1 to 3, since both the side edge portions of the film are gripped by pins or others~ holes are not preferably formed in both the side edge por~ions of the film 40 but are formed only in the central portion of the film.
When holes are not formed in both the side edge portions, the film will not be toxn during wrapping or stretching.
When biaxial stretching of the perforated film 40 used as an original roll is biaxially stretched, the holes 42 are increased. The air-permeability density of the ~ilm is increased to improve air permeability.
The perforated film 40 having the enlarged holes 42 are suitable to wrap an article which requires a high air and moisture permeability and re~uires prevention of dew condensa~ion, such as vegetables and ~ruits This film requires a small number of turns in wrapping and is effective if the number of holes is small In addition, widthwise shrinkage of the film during stretching i8 small. Therefore, a wrapped body has a iarge width, and the wrapping ~ime can be shortened.
In addi~ion, the amount of material film is small, cost is low, and an amount of ma~erial waste is small.
Fig. 7 is a plan ~iew showing a film 44 with an additive. Fig. 8 is a sectional view showing the film 44 with an additive. Reference numeral 46 denotes an additive. The film 44 wi-th the additive is obtained by adding an inorganic powder (filler) and a foaming agent serving as a substantial foreign material in a material polymer during film formation. In the film 44 with the additive, the additive 46 serves as a nucleus to form a hole during stretching or upon stretching. The perforated ~ilm 44 has the same effect as the perforated film 40 described above. Examples of the additive for forming a hole are a calcium carbonate powder, a magnesium carbonate powder, a talc powder, a titanium oxide powder, a carbon black powder, a silicon oxide powder~ a calcium silicide powder, an aluminum 2~
silicide powder, an alumina powder, a kaoline clay powder, a silica powder, a glass powder, and various pigments. These additives are often inorganic powders.
However, in order to improve affinity of a film composition with a polymer, a plasticizer (e.g., dioctyl phthalate or glycerin) or a solvent (eOg., dimethyl sulfoamide~ may be used.

Fig. 9 is a perspective view of a corrugated film 48. The corrugated film 4~ is obtained by alternately arranging thick protrusions 50 and thin recessed portions 52. The protrusions 50 and the recessed portions 52 are aligned in a direction to form a predetermined angle with respect to a widthwise direction of the film 48. As shown in Fig. 10, when the corrugated film 48 is laterally stretched in the widthwise direction, some of the recessed portions 52 are torn to form a net. The net-like film 48 has the same effect as in the perforated film 40.
A net may be used in place of a film as an original roll. Fig. llA shows a ma~rix net. This net may be used in a combination of longitudinal stretching and lateral stretching. Fig. llB is a rhombic net having a width illustrated as a slightly increased width. This net does not have any weft componen~s.
When warp components of the net are slightly stretched in the widthwise direction to ~orm a rhombic or parallelogram-like shape. This net may be used in a combination of longitudinal stretching and lateral stretching. When a net is used as an original roll, an intersection of the warps may have a thic~ness larger than that of any other portion. However, any practical problem is not often posed.

25A net formed by an integral extrusion method is preferably used as an original roll ne~. However, a 3 ~

woven filament or tape may be used in place of the net.
Although the filament component constituting the original roll net is no~ stretched or is already stretched, it must be further strPtched. The forms of the nets are classified into a matrix net consisting of warp and weft components, and a rhombic net having no weft components but warp or oblique filament components. Since the matrix net has weft components, it canno~ be stxetched in the width~ise direction. In order to stretch the matrix net in the widthwise direction, lateral stretching must be performed. In any case, an increase in width or lateral stretching is used to perform air-permeable wrapping ha~ing a wide width although an original roll ne~ having a small width is used. When the original roll is not a rhombic net, it is used in a combination of longitudinal stretching and an increase in width. Longitudinal stretching or an increase in width may be performed first. Alternatively, an increase in width may be performed during stretching. Since ~he rhombic net does not have any weft components, all ~he components of the net can be almost stretched by longitudinal stretching, and an increase in width is also facilitated~ Alternatively, lateral stretching of a rhombic net is performed, and an increase in width and slight stretching of the constituting filaments can be performed. Methods used in film stretching and ~n ~ 3R -increase in width of the film may be used as net stretch means and a net width increasing means. Net s~retch means are disclosed in Japanese Patent Laid-Open Nos. Sho 62-97825 and 62~97829 proposed by the preseni inventors.
An une~en fabric may be used in place of a ilm as an original roll. Fig. 12 is an uneven fabric obtained by entangling, embossing, or adhesion of a large number of filaments. These filaments can be used in a combination of longitudinal stretching, lateral 1 stretching, and an increase in width. An une~en fabric may be one consisting of random filaments such as a spun bond uneven fabric. However, one-directional aligned filament of an nonaligned filament is particularly suitable for this purpose. Such an unwoven fabric is stretched in at least one direction to retain or hold an arkicle by a shrinkage tension caused by stretching. Methods used in film stretching and an increase in width of the film may also be used as an unwoven fabric stretch means and an unwoven ~ fabric width increasing means. A special perforating unit need not be used in unwoven fabric wrapping. When the unwoven fabric is used, the same effect as in formation of a large number of apertures can be obtained, and the outer appearance of wrapping can be ~5 aesthetically improved.

6~J ~ , 2 The second embodiment and its modifications of the present invention will be described with reference to Figs. 13 to 26B. Fig. 13 is a side view of this embodiment, and Fig. 14 is a plan view thereof. ~n original roll film 101 (film width wl) in the form of a roll is placed upright. The film is supplied with an almost predetermined tension (supply speed vl) and is guided to upper and lower stretch pulleys 103a and 103b. A table 102 on which the original roll film stands upright is illustrated outside the ~rame of the apparatus in Fig. 14, but can be stoxed within the frame upon rotation of an inner support point (not shown) which supports the table 102 after the original roll film is set. A direction of rotation o a drive unit 104 is changed by bevel gears 105a and 105b to rotate turn pulleys 106a and 106b. Belts 107a and 107b are driven by the turn pulleys 106a and 106b. The stretch pulleys 103a and 103b are rotated by these belts (speed v2~. The film may be slightly stretched by a supply tension and may be then fed to the stretch pulleys. (vl c v2).

Both side edge por~ions of the original roll film 101 are gripped by the endless belts 107a and 107b at a portion where a distance between the stre~ch pulleys 103a and 103b is the smallest. The distance between the gripped side edga portions of ~he film is defined as w2. The film whose both side edge portions are ~6~2 gripped by the belts 107a and 107b is st.retched in the widthwise direction along a spread path defined by the halves of the peripheries of the stretch pulleys 103a and 103b. The stretched film is xeleased from the belts and pulleys at a portion where a distance between the pulleys is the largest (a dis~ance between th~
gripped side edge portion6 of ~he film i~ de~ined as w3). The released film serves aæ a laterally stratched film 108 (overall film width W4). During lateral s~retching, heating is not generally required. When the diameter of each stretch pulley cannot be assured ko be suficiently large, the locus of the film running along the central pvrtion i8 shorter than that along the pulleys. For this reason, a nonstxetched portion is left in the central portion of the film. In pallet wrapping, slight vsriations in stretching do not pose any problem. However, when a nonstretched centxal porti~n is left conspicuously, the central portion of the film can be heated by an infrared heater 109 to per~vrm uniform stretching during an ini~ial period o~
stretching. During lateral stretching, a shrinkage force acts on the central film portion in the longitudinal direction when a stretch magnifica~ion is increased. ~he central film portion is suspended, as indicated by the alternats long and two short dashed curve f in Fig. 14. When this suspension as indicated by the curve f extremely occurs, the central portion is not stretched to result in nonuniform ~tretching. In order to prevent this, rotatable guide turn rolls 110-1, 110-2, 110-3,... are arranged so that each of their diameters is set almost equal to the outer diameter of each of the stre~ch pulleys 103a and 103b, thereby preventing the suspension indicated ~y the curve f and performing uniform stretching.
Two longitudinal stretch rolls llla and lllb ara set upright near a maximum spread portion defined by the lateral stretch pulleys 103a and 103b, respectively. A separate nip roll may be mounted on the longitudinal stretch roll lllb to keep a stretch tension. The roll lllb is driven by a line ~ha~t by a drive unit 4. A difference between a surface speed (v3) of the roll llla and a ~urface ~peed (v4~ of the roll lllb is determined by a gear xatio of gears 112a and 112b (although not shown in Figs. 14 and lS). A
film 113 longitudinally stretched by the rolls llla and lllb is wound around a cargo 175 at a speed v5 with a predetermined ~ension ~y a ten~ion control dancer roll 114. The predetermined ten~ion can be controlled by an electPical or mechanical tension controller, or a mechanism for obtaining the predetermined tension such that motion of the dancer roll is controlled by an air cylinder and a spring or a magnet.
The cargo 115 obtained by stacking articles (118-1, 118-2, 118-3,...) is placed on a pallet 117 on - ~2 -a turntable 116. An upper contact film 119 is placed o~ the upper surface of the cargo 115. The turntable 116 is driven by a motor 120. The cargo 115 is entirely wrapped by winding the film 113 around all the side surfaces of the cargo 115.
Although not shown, a unit for urging a freè
rotation sur~ace againsk the upper surface of the cargo to prevent misalignment of the cargo regardless of its rotation may be used.
The turntable 116 is rotated at a predetermined speed. Since the cargo 115 has a rectangular parallelepiped shape, a speed at which the film 113 is wound around a corner portion h is different from (higher than~ that at which the film 113 i6 wound around a flat portion i. A change in speed (i.e., a change in tension) can be absorbed by movement of the dancer roll 114. For example, when the initial speed of the turntable is set low, and the speed of the turntable is gradually increased, and when a change in ~peed cannot be absorbed by only the dancer roll, the position of the dancer r~ll is detected to change the speed of the drive unit 104, thereby absorbing the change in speed. ~nother method may be employed to control the drive unit 120 for ~he turntable 116 so that the speed at the portion h of the cargo is set almost equal to that of the portion i. ~lternatively, - ~3 -rotation of the turntable may be easily controlled by a torque motor.
When the width of a stretched film is smaller than the height of a cargo, ~he cargo on the turntable may be vertically moved and is wound with the strekched film, thereby wrapping all the side surfaces of the cargo with the film. ~lternati~ely, the s~retch apparatus may be vertically moved as a whole. It i6 .
easier to arrange a mechanism for vertically mo~ing the turntable than to arrange a mechanism for vertically moving the entire stretch apparatus.
The film stretch magnification can be defined as follows.
An apparatus lateral stretch magnification Nm and a substantial lateral stretch magnification Np as ~n overall width of the film are given as follows:
Apparatus Lateral Stretch Magnification Nm = w3/w2 Substaintial ~ateral Stretch Magnification Np =
w4/wl where wl is the width of the original roll, w2 i the width between the gripped side edge portion~ of the film at the pulley inlets, w3 i5 the width betw~en the gripped side edge portions of the film at the pulley outlets, and w4 is the width of the film wound around the article.
A longitudinal stretch magnification Mr of the apparatus roll and a substantial longitudinal stretch _ ~4 ~

magnification Mp from supply o~ the film to its winding a~ound the article are defined as follows^
Mr = ~4/v3 Mp - v5/vl where vl is the film supply speed, v3 and v4 are surface speeds of the longitudinal stretch rolls, and ~5 is the speed of winding the film around the article.
A total area stretch magnification X can be given as ~ollows:
X = Mp/Np = (w4 x v5)/~wl x vl) This second embodiment propose~ an easy to-handle stretch apparatus capable of effectively increasing the area s~xetch magnification X. As an effective means for this purpose, the longitudinal stretch rolls are located near the lateral stxetch apparatus. The longitudinal stretch means comprises an proximal stretch means in which rolls are close to each other.
In order to further clarify this, the longitudinal stretch apparatus in Fig. 14 is enlarged and illustrated in Fig. 15. When a distance L between the lateral stretch apparatus and the longitudinal stretch apparatus can be made small, longitudinal stretching can be performed between them. It is, however~
effective to perform proximal longitudinal stretching within a distance q between the longitudinal stretch rolls. With this arrangement, longitudinal stretching _ ~5 - 2~

is performed while widthwis~ shrinkage of the film in the lateral direction can be minimized. An easy-to-handle stretch means for maximizing the area stretch magnification X by a small lateral stretch magnification Mp and a large longitudinal stretch magnification ~p can be obtained. In this case, the lateral stxetch magnification Np must be the one enough to s~retch the film to have a width larger than the height of the article so as tv cover all the ~ide surfaces of the cargo 115 by using the given original roll film width wl. The distance L must be minimized and preferably 800 mm or les, and more preferably 200 mm or less. When the dis~ance L is set to be 800 mm or less, the wid~hwise shrinkage of the film upon lateral stretching can fall within the range of 10 to 20~
(depending on different types of films). When the distance L i5 set to be 200 mm or less, the shrinkage ratio can be set tc be 10% or less. When the distance L exceeds 800 mm~ the shrinkage ra~io exceeds 20% to degrade lateral stretch efficiency.
Longitudinal stretching may be performed between the longitudinal stretch roll llla and the lateral stratch pulleys 103a and 103b. ~owever, a widthwise shrinkage ratio is smaller in longitudinal stretching between the rolls llla and lllb capable of reducing the longitudinal stretch distance q than in longitudinal stretching between the longitudinal stretch roll llla and ~he lateral stretch pulleys 103a and 103b. The s~retch distance q is preferably set small. if the stretch distance q is, however, excessively small, workability in initial film setup and removal of the film from a roll is degraded. Ther~fore/ the g value is ~et to be 200 mm or less, and preferably ~0 mm to 5 mm.
One of the ~haracteristic featureg of the second embodiment is tha~ ~he stretch magnification can be changed when the height of the cargo 115 is changed.
Therefore, the winding film width w5 can be controlled to be larger than the height of the cargo but not to be excessively larger than that, thereby preventing waste of the film. The stretch magnification can be easily changed by changing gripping ~ositions at the inlets or outlets of the pulleys/ or the like. ~his flexibility is inherent ~o such an easy to-handle lateral stretch apparatus.
Fig. 16 shows a mechanism for changing a lateral stretch magnification in this embodiment. Shafts 121a and 121b of the pulleys 103a and 103b are rotatably supported on bearings 123a and 123b, respectively.
Arcuated elongated holes 125a to 125d are formed in a frame 122. The bearings 123a and 123b are fixed on the frame 122 ky bolts 124a to 124d respeckively extending through the elongated holes 125a to 125d. When the bolts 124a and 124d are loosened, moved along the - ~7 -L ~
elongated holes 125a ~o 125d, and tightened again to change the angles of the bearings 123a and 123b.
Therefore, the angles of the shafts 121a and 121b can be changed to change an open angle between the pulleys 103a and 103b, ~hereby changing a stretch magni~ication.
The stretch magnifica~ion change mechanism is not limited to that shown in Fig~ 16. Fig. 17 shows another arrangement for changing a film str~tch magnification. A roller 126 located immediate~y before a film is supplied to the pulleys 103a and 103b is movable. For example, when the roller 126 is moved from a posikion 126a to a position 126b, the position of ~he pulleys 103a and 103b which grip the film is changed from a position X to a position Y. Therefore, the film stretch magnification can be changed.
The stretch pulley and ~he mating belt generally comprise a V-pulley 130 and a mating V-belt 131 (a two-sided ~-belt may be used~, respectively, as shown in Fig. 18A. However, the shape of the belt is not limited if it can be fitted in a groove. A pulley 132 having a plurality of grooves shown in Fig. 18B may be used, and a plurali~y of belts tl33 and 134) may be fitted in these grooves. This arrangemsnt is e~fective for a film having a large stretch tension. When a film has a small stretch tension, a flat belt and a flat pulley may be used. As shown in Fig. 18C, projections may be formed on a flat belt 13S and a flat pulley 136 t~ effectively increase a gripping force.
Fig. l9 shows another arrangement of a lateral stretch rotary disc. A lateral stretch disc obtained hy orming a large number of press members 141-1,....
141-n in the peripheral portion of such a disc 140 may also be used. Reerring to ~ig. 19, the press member 141-1 is urged by a spring 143-1 to grip a film 142 with a lower disc 144. A fixed bottom plate 145 is mounted Oll this disc. When the length of a rib 146 formed on the peripheral portion of the bottom plate 145 is larger, the film can ba gripped by ~he behavior of the spring. At a position where the film is released, the rib is short, as indicated by a rib 146', so it does not receive ~he biasing force of the spring.
In this arrangement, although the spring is used, gripping can be performed by using a pneumatic force produced by an air cyli~der, as disclosed in Japanese Patent Publication No. Sho 63-44049.
Fig. 2~ shows another disc. This disc is a lateral stre~ch disc obtained by forming a large number of needle-like pins 148-1, 148-2, 148-3,... on the circumferential suxface of a disc 147. These pins are hooked by both side edge portions of a film to vertically stretch the film along a spread path defined by the upper and lower discs.

rrhe lateral stretch mechanisms using the discs qccording to this embodiment are simple. By using each mechanism described above, loci of both the side edge portions of the film along the discs are longer than those of the central portions of the discs, and the central portion o~ the film i~ inevitably made ~hick.
When the diameter of the disc is increased, the diff~rence in thickness can be reduced. ~owever, a large disc is not suitable for an easy-to-handle lateral stretch apparatus. In order to reduce the above stroke difference, some of the guide turn rolls 110-1, 110-2,..., which are flat i~ Figs. 13 and 14, are replaced with barrel rolls 149 shown in Fig. 21.
The central portion of the barrel roll 149 extends outside the outer periphery of the disc to reduce this stroke difference.
When a stretch ~ilm is lateral stretched, necking is performed so that nonstretched portio~ are left in the ~orm of stripe~. No praatical problem is posed in stretch wrapping even if some nonstretched portions are left in the film. When the nonstretched portions are localized, a binding force distribution on the article becomes nonuniform, thus posing a problem. In order to soLve this problem, ring-like guide rolls 153-1, 153-2, 153-3,... are arranged in the spread path defined by the lateral stretch discs 150a and 150b shown in Fig. 22. These ring-like guide rolls 153-1, 153-2, ~ 50 - ~3 ~ 5~J

153-3,... are arranged in guide turn rolls 152-1, 152-2, and 153-3 for guiding the fîlm 151 to be laterally stretched and are aligned along the spread stretch path. With this arrangement, nonstretched portions 154-1, 154-2, 154-3,... of a laterally stretched film 151 are spxead throughout the film and are almost uniformly distributed. In the arrangement of Fig. 22, although the diameters of all the guide rolls are identical, the diameters of cen~ral rolls are set to be larger than those of end rollers close to the stretch discs, thereby obtaining the same effect as in the barrel rolls in Fig. 21.
The pair of upper and lower lateral stretch rotary discs are symmetrical with each other about a disc ha~ing the same diameter in Figs. 13 and 14. However, these upper and lower discs may be discs having different diameters and arranged asymmetrically, as shown in Fig. 23. A lower disc 155b is disposed parallel to the ground surface, and an upper disc 155a is inclined from the ground surface. The upper disc 155a has a larger diameter than that of the lower disc 155b. With ~his arrangement, a heavy original roll film can be located at a lower position. When a stretch magnification is tG be changed, only the inclination angle of the disc 155a is changed without moving the position of ~he original roll or the disc 155b.

51- 2~

The laterally stretched film has large widthwise shrinkage immedia~ely after lateral stretching or during longitudinal stretching after lateral stretching. In this case, in order to reduce shrinkage, an appropriake width increasing means (widthwi~e shrinkage preventing means) can be preferably arranged immediately after lateral stretching, during longitudinal stretching, or before or after longitudinal stretching. Fig. 24 shows a conical member as this widthwise shrinkaye preventing means arranged at the outlet of the lateral stretch apparatus. An original roll 160 comprises a net. This net 160 is hooked and gripped by a large number of pins 162 formed on the circumferential surface~ of pin type lateral ~tretch discs (the discs are as shown in Fig. 1~ located in the inverted V-shaped spread path and is then l~terally stretched, thereby o~taining a laterally ~tretched net 163. A turn roll 164 (thi~
roll may be reely rotated or dri~en~ is lDcated at the outlet of the lateral stretch disc. Conical members (i.e., tapered rotary members) 165a and 16~b each having a frustoconical shape are located at positions where both end side edge portions of tha film on the surface of the turn roll 164 reach. Each conical member may be freely rotated by in~erting a bearing therein, ox may be fixed on the turn roll 164 and can be rota~ed together with the turn roll 164. The _ 52 - ~i3 conical members 165a and 165b are arranged such that large-diameter portions are directed toward the side edge portions o~ the film. The turn roll 164 may be constituted by the first one of the longitudinal stretch rolls. The conical members 165a and 165b effectively prevent widthwise shrinkage of the film and can actually prevent wid~hwise shrinkage by about 10%.
Fig. 24 exemplifies the pin type rotary discs and the net. The same effect as described above can be obtained by using other stretch rotary discs and other films. Note that normal expander rolls, cross guiders, or arcuated bars may be used in place of the conical members 165a and 165b.
Figs. 25A and 25B show another widthwise shrinkage preventing means. Fig. 25A shows a large n~mber of conical members 167 of a frus~oconical shape mounted on an arcuated bar 166. A bearing is mounted in each conical member 167, and ~he conical member 167 can be freely rotated. ~he arcuated direction of the bar 166 corre~ponds to a d~rectivn to cause the ~ilm to ~low, as indicatsd by an arrow in Fig. 25A. Fig. 25B is a sectional view of one con~cal member 167. A bearing 168 is moun~ed in the conical member 167. Although the widthwise shrinkage preventing means shown in Fig. ~4 ?.5 and Figs. 25A and 25B are effectively disposed immediately after li~teral stretching as shown in Fig. 23, as described above, they can be arranged I!J 2 immediately af-ter longitudinal s~retching to obtain a sufficient shrinkage preventing effect because the lateral stretch discs are located near the longitudinal stretch rolls.
As opposed to lateral stretching of the film in the vertical direc~ion, as shown in ~igsO 13 and 14, the film may be horizontally located, lateral stretching may be performed to wrap an article with the film. This is illustrated as an apparatus in Figs. 25A
and 26B. More specifically, this apparatus wraps a roll article 170. The article is rotated about a core, and a stretch film is wound around the surface of the article, thereby wrapping the article. Fig. 26A is a plan view of the wrapping appara~u6 for the roll article 170. The original roll 171 is laterally stretched by stretch rota~y discs 172a and 172b (these are simplified for the sake of illustrati~e conv nience, and may be stretch rotary discs each consisting of a pulley and a bel~ in Fig. 13, gripper type discs in Fig. ~9, or the ~tretch rotary discs each having a large number pins extending on its circumferen~ial surface in Fig. 20). The laterally stretched film is longitudinally ~tretched between longitudinal stretch rolls 173 and 174. The article 170 is supported by a coupling 177b rotated by a motor 176 arranged on a table 175 and a free rotation coupling 177a having a bearing therein. ~ stretch film - 5~ -~ s3 is wound around the article 170. Fig. 26A shows a center drive winding method, and Fig. 26B shows a surface drive winding unit. The roll article 170 is placed on rolls 178a and 178b. At least one of the rolls 178a and 178b is rotated by driving. Upon rotation of the rolls, the article 170 is rotated, and a stretch film 179 is wound around the article 170.
belt may be looped between the rolls 178a and 178b to wrap a spherical or cylindrical ar~icle (e.g., grass) on ~he belt. Wrapping of the articles by using a turntable or a central or surface drive scheme is known well to those skilled in the art. When thi~ wrapping is combined with the lateral stxetch apparatus of the pre~ent invention, the film wid~h can be increased, and ~he number of turns can be reduced. In addi~ion, the amount of film used can be largely reduced, and the time and the resource can be reduced.
The disc type stretch apparatus serving as a lateral stretch apparatus of thi~ embodiment can stereoscopically use the space. For this reason, ths apparatus can be made compact, and the installation floor area can be reduced. Since the film can be stretched with both the side edge portions being gripped, the stretch magnification can be increased, and stretching can be properly performed. Since the apparatus can be easy to use, the appara~us cost is low. In particular, in a pulley type s~retch - 55 - ~ '5 :~¦ 3 apparatus, since commercially available pulleys and belts can be used, operations are simple and the appara~us is inexpensive. Since the apparatus is easy to use, a stretch magnification can be changed in accordance with the height of the article, and workability in repair and transportation of the apparatus can be impro~ed.
Another characteristic feature of the disc type lateral stretch apparatus is to provide the following functions by a combination of a pair of discs although the stretch apparatus is easy to handle.
(a) Parallel por~ions not subjected to lateral stretching are present a~ the inlets of the discs r and these portions are used to preheat the film.
(b) The film can be laterally stretched by the subsequent spread path.
(c) Parallel portions are also present at the end of stret~hing, and alignment of the molecules in the stretched state i~ stabilized in these parallel portions (heating is stabilized in a heated state).
(d) When both ~he side edge portions are kept gripped passing through a maximum s~retch portion, the width of the film is then reduced. When the film is kept gripped until this area, the film is kept gripped in a slightly shrunk state, so that film shrinkage can be reduced after the film is released from the discs (shrinkage heating is performed in a heated state).

56 - 2 ~ L ~ 2 (e) The position at which the film is gripped a-t the inl ts of the discs and the position where the laterally stretched film is released at the outlet~ of the discs are changed to change a s~retch magnification.
The preferable range of the lateral stretch magni~ication in ~he second embodiment is the same as that in the first embodiment. The film is stre~ched to have a width larger than the height of the article and can wrap almost all the side surfaces o~ the article by one turn, as in the first embodiment.
When the haight of an article is very large and all the side surfaces of the article cannot be wrapped with ~he film by one turn, a lift device may be mounted I5 on ~he ~urn~ahle to verti~ally move ~he article while being rotated, thereby wrapping the article with the film.
In the second embodiment, either longitudina~
s~retching or latexal s~retching may be performed first as in the first emhodiment. Longitudinal stretching, however, is preferably performed after lateral stretching is performed due to the ~ame reason as in the first embodiment. As a longitudinal stretch apparatus, a stretch apparatus having a simultaneously biaxial mechanism for laterally stretching the film in the disc type lateral stretch apparatus may be used (Japanese Patent Publication No. Sho 46 15438).

A plurality of longitudin~l s~retch appa~atuses and a plurality of lateral s~retch apparatuses may be arranged to perform stretch a film by a multi-stage system.
A polymer used as an original roll film in this embodiment is the same as exemplified in the first embodiment. Articles to be wrapped in this embodiment are also the same as those in the first embodimen~.
According to the second embodiment, the same effect as in the first embodiment can be obtained. In particular, since the lateral stre~ch apparatus is an easy-to-handle disc type lateral stretch apparatus, the apparatus cost is low, the ins~allation space is small, and workability can be improved.
The second embodiment described above exemplifies a film as an original roll. However, other original rolls shown in Figs. 6 to 11 may be used. The same effects in use of these original rolls as in ~he first embodiment can be obtained.
The third embodiment of the present in~ention will be described with reference to Fig~. 27 and 28.
Figs. 27 and 28 show a wrapping sy~tem using a portable pin tenter lateral stretching apparatus, in which Fig. 27 is a side view thereof, and Fig. 28 is a plan view thereof. An original roll 201 in the form of a roll stands upright on a table 202. This original roll is a perforated film. The width of the original roll is smaller than the height of an article 211.

Reference numerals 213 denote holes formed in the film.
Upper and lower chains 203a and 203b are guided by chain wheels 204a-1, 204a-2,.... A large num~er of needle-like pins 205a-1, 205a-2, 205a-3,... (to be brie~ly described as pins 205 hereinafter) extend on the chains 203a and 203b. The chains 203a and 203b, the chain wheels 204a-1, 204a-2,..., and the pins 205 constitute a pin tenter lateral stretch apparatus. A
combination of the chain and the chain wheel can be replaced with a combination of a belt and a pulley.
Both side edge portions of the perforated film 201 are hooked and gripped by the pins 205.
The perforated film 201 is laterally stretched along the vertically spread path defined by ~he chains 203a and 203b. Tha sizes of the holes 213 are increased by lateral stretching to increase an air-permeability density to improve air permeability.
The film 201 serving as an original roll is stretched to have a width larger than the height of the article 211. Ater the film is stretched at a predetermined magnification tpreferably an apparatus stretch magnification of 2.2 times or morè), the chain path becomes parallel. Alignment of the polymer molecules of the stretched film is stabilized in the parallel portion of the chai.n path. The film is released from the pins 205 at the terminal end of the tenter, thereby obtaining a stretched perforated film 206. The width _ 59 -of the lakerally stretched film 206 is larger than the h,eight of the article.
A roll 207 having tapered rotary members 208 for pre~enting wid~hwise shrinkage of the laterally stretched film is arranged in the nex~ stage of the pin tenter unit. The tapered rotary members 208 are located at both the side edge portions of the perforated film 201. The widthwise shrinkage o~ the film 206 laterally stretched by the pin tenter unit tends to occur. In order to prevent this, the film runs anA is stre~ched in the widthwise direction while bokh the side edge portions of the fiLm 206 are kept pressed by the tapered rotary members 208, thereby preventing widthwise shrinkage of the laterally stretched film.
In the next step, the article 211 is being rotated on the turntable 210, and almost all the side surfaces of the article 211 can be wrapped with the laterally stretched perforated film 209 by a plurality of revolutions~ Almost all the side surfaces of the article 211 are wrapped with a laterally and longitudinally stretched film 209. The stretched film 209 is wound around all the side surfaces of the article 211 so that one side edge portion of the film 209 extends from the upper or lower end of the article 211. Reference numeral 209a denotes one side edge of the film 209 which extends from the upper or lower end of the axticle 211. The turntable 210 is kept rotated at a constant rotation speed by a motor 212 or constant tension by a torque motor. Therefore, wrapping using a perforated film is completed.
In the third embodiment, since the perforated film is used as the original roll, the film is suitable to wrap an ar-ticle which requires a high air and moisture permeabili~y and requires prevention of dew condensation, such as vege~ables ~nd fruits. This film requires a small number of turns in wrapping and is effective if the number of holes is small. In addition, widthwise shrinkage of the film during s~.retching is small. Therefore, a wrapped body has a large width, and the wrapping time can be shortened.
In addi~ionr the amount of matexial film is small, cost is low, and an amount of material waste is small. In conYentional applications, i.e., in a field of wrapping requiring air permeability and allowing.large holes and in an application for maximally exposing contents upon wrapping, a net-like material i8 longitudinally stretched. According to the ~hird embodiment, a large area can be assured by the same net as in the conventional technique, and the wrapping cost can be reduced. In addition, the wrapping time can be shortened. In addition, an amount of web to be ~reated upon unwrapping is advantageously small.

- 61 ~ Y~ 3 The size and n~mber of holes can be determined in consideration of air permeability for a wrapping purpose, a retained tension of a web on an article, and the like. Each hole may be cons~ituted by a slit. The film 44 with an additive shown in Figs. 7 and 8 may be used in place of the perforatPd film. Altexnati~ely, the corruga~ed film 48 shown in Fig. g may be used, the nets shown in Figs. llA and llB may be used, or the unwoven fabxic shown in Fig. 12 may be used.
In the third embodiment, the lateral str~tch apparatus is not limited to the one shown in Figs. 27 and 28, but can be replaced with another one. For example, the lateral stretch apparatus shown in Figs. 3 and 4, Figs. 13 and 14, or Fig. 23 may be used.
~he guide roll shown in Pig. 25 may be u~ed in place of the roll 207 having the tapered rotary members 208.
The fourth embodiment of the present invention will be described with re~erence to Figs. 29 and 30.
20 Fig8. 29 and 30 show a wrapping sys~em using a lateral stretch apparatus, in which ~ig. 29 is a side view thereof, and Fig. 30 is a plan view ~hereof. An original roll 301 in the form of a roll stands upright on a ~able 302. This original roll is a perforated film. Reference numerals 313 denote holes formed in the film. L~ngitudinal stretch rolls 307 are located next to the table 302, and a dancer roll 308 is located next to the longitudinal stretch rolls 307a and 307b.
T~he perforated film 301 is longitudinally stretched by the longitudinal stretch rollers 307a and 307b. The sizes of the holes 213 are increased by this lateral stretching to increase an air-permeability density, thereby improving air permeability. The tension of a longitudinally stretched perforated film 309 is controlled by the dancer roll 30g A turntable 310 is located next to the dancer roller 308. The tuxntable 310 is rotated at a constant speed using a motor or at a constat tension u~ing a torque motor. On the other hand, the table 302, the lo~gi~udinal stre~ch rolls 307a and 307b, and the dancer roll 308 are supported by frames 315 and 316 These can be vertically moved by a lift unit 314 in directions indicated by a double-headed arrow.
The longitudinally stretched film 309 is supplied while the table 302 and the longitudinal stretch roll 307a are moved upward (or downward) by the lift unit 314. At the same time, the turntable 310 is rotated.
By a plurality of revolutions or turns, the longitudinally stretched film 309 is wound around the article 311 placed on the turntable 310, thereby wrapping almost all the side surfaces of the article 311, thereby completing wrapping with a perforated ilm.

This fourth embodiment has the same effect as in the third embodiment because a perforated film is used as an original roll.
Each hole in the perforated film may be a slit.
The film 44 with an additive shown in Figs. 7 and 8 may be used in place of the perforated film.
Al~ernatively, the corrugated film 48 shown in Fig. 9 may be usedj the nets shown in Figs. llA and llB may be used, or the unwoven fabric shown in Fig. 12 may be used. In the fourth embodiment, the longitudinal stretch apparatus is not limited to the one shown in Figs. 29 and 30, but may be replaced with another one.
In addition, instead of lifting the table 302 and the longi~udinal stretch roll 307a, the turntable 310 may be lifted.
The ifth embodiment of the present invention will be described with reference to Figs. 31 and 32.
Figs. 31 and 32 are schematic views showing a step of increasing a width of a slit film, in which Fig. 31 is 2~ a side view thereof, and Fig. 32 is a plan ~iew thereof. An original roll 401 wound in the form of a roll stands upright on a table 402. This original roll is a perforated film. Reference numerals 413 denote ~ holes (slits in this case3 formed in the film. This perforated film 401 is suppli~d and longitudinally stretched between longitudinal stretch rolls 403a and 403b. When a distance between the longitudinal stretch - 6~ _ 2 ~ 3~

rolls 403a and 403b is small, proximal stretching is performed. By this proximal stretching, the sizes of the slits 413 of the film are increased to have slightly increased widths, so that the air-permeability density of the film is increased ~o improve air permeability. The width of the stretched film is increased ~y an arcua~ed bar 405 and cross guiders 406a, 406b, 407a, and 407b through a turn roll 404. sy this operation, the widths of the slits 413 are increased, and the resultan~ $ilm is supplied to a step of wrapping an article with the f.ilm.
In this embodiment, the width is increased after longitudinal stretching. However, longitudinal stretching may be performed after the width is increased.
This fifth embodiment has the same effect as in the third embodiment because a perforated film is used as an original roll.
Each hole in the perforated film may be a slit.
The film 44 with an additive shown in Figs. 7 and 8 may be u~ed in place of the perforated film.
Alternatively, the corrugated film 48 shown in Fig. 9 may be used, th~ nets shown in Figs. llA and llB may be used, or the unwoven fabric shown in Fig. 12 may be used.

In the fifth embodimentt the longitudinal stretch apparatus is not limited to the ons shown in Figs. 31 and 32, but may be replaced with another one.
The sixth embodiment of the present invention will be described with reference to Fig. 33.
Fig. 33 shows an arrangement for forming holes after a film is laterally s~retched. An original roll film S01 is supplied and laterally stretched by a lateral stretch apparatus 502. The laterally stretched film is supplied from a roll 503 and is subjected to perforation by a pin roll 505. A large number of pins 504 extend on the pin roll SOS. The pin roll 505 is heated to a temperature exceeding a melting poink of the film, and the heated pins 504 are brought into contact with the laterally stretched film 506, thereby formlng a large number of holes by heat. A large number of axticles 508 placed on a rotating turn~able 507 are wrapped with the perforated film 506. In this process, when a film is not perforated, the film is laterally stretched and is subjected to large widthwise shrinkage. Therefore, widthwise shrinkage can be advantageously reduced by perforating the film.
Figs. 34A and 34B show a lateral stretch means.
Fig. 34A shows a pair of longitudinally grooved rolls 511 and 512. A large number of protrusions 513 and a large number of recessed grooves 514 are formed on the surface of each of the rolls 511 and 512. Fig. 34B

- 66 ~ 2 shows a state wherein a film 51~ is inserted between these two rolls and is laterally stretched. When a plurality of stretch roll pairs are arranged, a lateral s~retch magnifica~ion can be increased. In lateral stretching using these longitudinally grooved xolls, since the width of the film is not increased, this arrangement must be combined with a width increasing means.
The lateral stretch means is not limited to the one shown in Fig. 34 but may be replaced with another one. For example, the lateral stretch means shown in Figs. 1 to 4 or Fig3. 13 to 23 may be used.
Figs. 3S and 36 show a pin roll. Fig. 35 is a sectional view o a roll, and Fig. 36 is a side view thereof. ~ larga ~umber ~f pins 522 extend on a roll 521. A heater 525 may be inserted into this roll 521, and the roll 521 itsel~ may e heated upon energization using a slip ring. A punching roll or an embossing roll may be used in place of this pin roll. When a film is to be perforated, a mating roll may be preferably arranged at a position opposite to the perforating roll ~hrough a film.
Fig. 37 shows a cutting blade longitudinal slitter. Cutting blades 524 are mounted on a disc~ e spacer 523. The spacers with the blades are stacked in different phases to constitute a slitter roll. In place of this slitter, a heat blade slitter disclosed - 67 _ J

in Japanese Patent Publication No. Sho 61-11757 issued to the presen-t inventors, various types of spli-tters or slitters in the manu~acture of split yarns can be used.
~he seventh embodiment of the present invention will be described with reference to Figs. 38 and 39.
Figs. 38 and 39 show a wrapping system using a longitudinal stretch apparatus, in which Fig, 38 is a side view thereof, and Fig. 39 is a plan ~iew thereof.
An original roll 601 wound in the form of a roll stands upright on a table 602. The supplied original roll is perforated by a pin roll 603 immediately before longitudinal stretching. A pin roll shown in Fig, 33 or ~igs. 33 to 37 may-be used as the pin roll 603.
Reference numerals 613 deno~e holes formed in the film.
Longitudinal stretch rolls 607 and 607b are located next to the pin roll 603. A dancer roll 608 is located next to the longitudinal s~retch rolls 607a and 607b.
The film 601 perforated by the longitudinal stretch rolls 607a and 607b is longitudinally stretched. Sizes of the holes 613 are increased by longitudinal stretching. A tension of a longitudinally stretched perforated film 609 i6 controlled by the dancer roll 608. A turntable 610 is located next to the dancer roll 608. The turnta~le 610 is rotated at a constant spePd using a motor or at a constant tension using a torque motor. On the other hand, the table 60~, the longitudinal stretch rolls 607a and 607h, and the dancer roll 608 are supported by frames 615 and 616.
T~ese members can be lifted by a lift unit 614 in directions indicated by a double-headed arrow.
The longitudinally stretched film 609 is supplied while the table 602 and the longitudinal ~tretch roll 607a are mo~ed upward (or downward) by the lift unit 614. At the same time, the turntable 610 is rotated.
By a plurality of revolutions or turns~ the longitudinally s~retched film 609 is wound around the article Çll placed on the turntable 610, thereby wrapping almost all the side surfaces of the article 611, thereby completing wrapping with a perforated film.
This seventh embodiment has the same effect as in the third embodiment because a perforated film is used as an original roll.
Each hole may be a slit. In the seventh embodiment, the longitudinal stretch apparatus is not limited to the one shown in Figs. 38 and 39, but may be replaced with another one. Instead of lifting the table 602 and the longitudinal stretch roll 607a, the turntable 610 may be lifted.
The eighth embodiment of the present invention will be described with reference to Fig. 40.

In a system for longitudinally stretching a film after lateral stretching is performed and for wrapping a large number of articles rotated on a turntable with ~ ~ S~ S'~

a shrinkage tension produced by its stretching, an arrangement for forming holes in a ~ilm in longitudinal stretching is shown in Fig. 40. ~ original roll film 701 is supplied and laterally stretched by a lateral stretch apparatus 702. The laterally stretched film is then longitudinally stretched between post-longitudinal s~retch rolls 703a and 703~. The sur~ace speed of the roll 703b is larger than that o~ the xoll 703a by a longitudinal stretch magni~ication. In the arrangement for performing longitudinal stretching, a roll 705 having a large number of pins 704 on its surface is arranged. The pin roll 70~ is heated ~o a temperature exceeding a film melting point. The heated pin~ 704 are brought into contact with the film during longitudinal stretching ~o form a large number of pins 704 in the film 706. The perforated film 706 wraps the large number of articles 708 together located on the rotating turntabie 707 with a shrinkag~ tension generated by stretching of the film. In ~his process, when a film is not perforated, the film is laterally stretched and is subjected to large widthwise shrinkage. Therefore, widthwise shrinkage can be advantagaously reduced by perforating the ~ilm.
The lateral stretch means described with reference to Fig. 34 may be used. The lateral stretch means described in Figs. 1 to 4 or Figs. 13 to 23 may be _ 70 - ~$~

used. A pin roll 703 may be replaced with the one exemplified in Fig. 33 or Figs. 35 to 37.
The ninth embodiment of the present invention will be described with reference ~o Figs. 41 and 42.
Figs. 41 and 42 are schema~ic views showing ~ step of increasing a width of a slit ~ilm, in which Fig. 41 is a side view ~hereof and Fig. 42 is a pla~ ~iew -thereof.
An original roll 801 wound in the forlTI of a roll stands upright by a table 802. Slits are formed in the supplied original roll 801 by a longitudinal slitter roll 803. That is, staggered slits are formed by the longitudinal slitter roll 803 rotated at a surfac~
speed higher than a film speed. A roll shown in Fig. 37 may be applied as the longitudinal slikter roll 803. Reference numerals 813 denote slits. This film 801 is longitudinally stretched between longitudinal stretch rolls 803a and 803b. Wh~n a distance between these longitudinal stretch rolls 803a and 803b is small, proximal stretching i~ performed. By khis proximal stretching, the widths of the film slits 813 are increased to have slightly increased widths. The width of the s~retched film is increased by an arcuated bar 805 and cross guiders 806a, 806b/ 807a, and 807b through a turn roll 804. The widths of the slits 813 are increased by a width increasing operation.
Thereaft2r, the film is supplied to a step of wrapping an axticle.

2 ~

In this embodiment, an increase in width is performed after longitudinal stretching is performed.
However, slits may be formed after longitudinal stretching is performed. Alternatively, longitudinal stretching may be performed afte~ the slits are formed and their widths are increased. As another method, a longit~dinal slitter may f~rm slits in a laterally stretched film.
In the ninth embodiment, since the film is perforated or slitted, and the widths of the slits are increased, the same effect as in the third embodiment described above can be obtained. In the ninth embodiment, the longitudinal s~etch apparatus is not limited to the one shown in Figs. 4~ and 42. Any other 1~ lonyitudinal stretch apparatus may be used.
As has been described above, according to the present invention, there are provided an easy-~o-handle, compact wrapping apparatus using a small amount of ori~inal roll used and having a short 2~ wrapping time, and a method therefor. There are also provided a wrapping apparatus capable of providing a wrapping form which provides air- and moisture-permeable properties and prevents dew condensation and capable of reducing widthwise shrinkage in the stretching process, and a method therefor.

Claims (27)

WHAT IS CLAIMED IS

1. A wrapping apparatus for stretching a band-like member and winding the stretched band-like member around an article, comprising:
means for supplying a band-like member;
lateral stretch means for stretching the band-like member at least in a lateral direction, said lateral stretch means being provided with means for running the band-like member so as to spread the member like an unfolded fan and means for gripping regions respectively near the opposite widthwise ends of the band-like member in such a manner that the regions are detachable from said running means; and means for winding the stretched band-like member around the article.

2. An apparatus according to claim 1, wherein said running means comprises: a first running portion moved along a first endless route having a first forward path used for running of the region near one of both the widthwise ends of the band-like member and a first backward path not used for running of the band-like member; and a second running portion moved along a second endless route having a second forward path used for running of the region near the other one of both the widthwise end portions of the band-like member, the second forward path and the first forward path being gradually increased as the band-like member runs, and a second backward path not used for running of the band-like member.

3. An apparatus according to claim 2, wherein said running means comprises a first rotary disc having a peripheral portion constituting said first running portion and a second rotary disc having a peripheral surface constituting said second running portion, and said gripping means comprises a first gripping member for fixing the region of the one widthwise end of the band-like member so that it is detachable from said first running portion, and a second gripping member for fixing the region of the other widthwise end of the band-like member so that it is detachable from said second running portion.

4. An apparatus according to claim 3, further comprising guide means for guiding the band-like member gripped by said gripping means.

5. An apparatus according to claim 4, wherein said guide means comprises a guide member for guiding the band-like member so that a difference in running length of the band-like member is reduced in the widthwise direction.

6. An apparatus according to claim 5, wherein said guide member comprises a first guide portion for guiding a central portion of the band-like member and a second guide portion for guiding portions between the central portion of the band-like member and the opposite widthwise ends thereof.

7. An apparatus according to claim 1, further comprising means for heating the band-like member.

8. An apparatus according to claim 1, further comprising longitudinal stretch means for stretching the band-like member in the longitudinal direction thereof.

9. An apparatus according to claim 8, wherein said longitudinal stretch means comprises a longitudinal post-stretch mechanism for longitudinally stretching the band-like member after the band-like member is laterally stretched by said lateral stretch means.

10. An apparatus according to claim 9, wherein said longitudinal post-stretch mechanism comprises a stretch member for longitudinally stretching the laterally stretched band-like member released from said running means while the amount of widthwise shrinkage caused by a widthwise shrinking force of the laterally stretched band-like member is small.

11. An apparatus according to claim 9, wherein said longitudinal post-stretch mechanism comprises means for longitudinally stretching the band-like member at a winding speed of said winding means, which is made higher than a band-like member running speed of said lateral stretch means.

12. An apparatus according to claim 8, wherein said longitudinal stretch means comprises longitudinal pre-stretch mechanism for longitudinally stretching the band-like member before the band-like member is laterally stretched by said lateral stretch means.

13. An apparatus according to claim 12, wherein said longitudinal pre-stretch mechanism comprises means for longitudinal stretching the band-like member at a band-like member introducing speed of said lateral stretch means, which is made higher than the band-like member supply speed of said supplying means.

14. An apparatus according to claim 1, further comprising means for regulating a winding tension of the band-like member around the article.

15. An apparatus according to claim 1, further comprising means for rotating the article to wind the band-like member around the article.

16. An apparatus according to claim 15, wherein said rotating means comprises a turntable on which an article placing region having a predetermined height is defined, and said lateral stretch means comprises means for stretching the band-like member in the lateral direction so that the band-like member has a larger width than the height of the article placing region.

17. An apparatus according to claim 15, wherein said rotating means comprises means for rotating the article about an axis except for a vertical axis.

18. An apparatus according to claim 1, further comprising means for preventing widthwise shrinkage of the laterally stretched band-like member.

19. An apparatus according to claim 1, further comprising means for changing a stretch magnification.

20. A wrapping apparatus for stretching a band-like member and winding the stretched band-like member around an article, comprising:
means for supplying the band-like member;
means for stretching the band-like member in at least one of longitudinal and lateral directions thereof;
means for winding the stretched band-like member around the article; and hole forming means forming holes in the band-like member before the band-like member is wound around the article.

21. An apparatus according to claim 20, further comprising means for heating said hole forming means.

22. An apparatus according to claim 20, wherein said hole forming means comprises means for forming slits parallel to the stretching direction of said stretch means.

23. An apparatus according to claim 20, further comprising width increasing means for increasing the width of the band-like member stretched by said stretch means and perforated by said hole forming means.

24. A wrapping method comprising the steps of:
supplying a band-like member;
stretching the band-like member to increase an air-permeability of the band-like member; and winding the stretched band-like member around an article.

25. A method according to claim 24, further comprising the step of increasing the width of the stretched band-like member.

26. A method according to claim 24, wherein the band-like member is a perforated band-like member or a band-like member perforable by stretching.

27. A wrapping method of winding a band-like member around an article, comprising the steps of:
supplying a band-like member having a width smaller than that of the article;
stretching the band-like member to have a width larger than that of the article in at least lateral direction; and winding the stretched band-like member around the article such that the band-like member cover all side surfaces of the article by one turn, and one side edge portion of the band-like member extends from at least one of upper and lower ends of the article.