US3181956A - Packaging method and machine - Google Patents

Description

May 4, 1965 K. G. CLARK ETAL PACKAGING METHOD AND MACHINE 'r Smeets-sheet 1 Filed June 13, 1962 May 4, 1965 K. G. CLARK ETAL PACKAGING METHOD AND MACHINE 7 Sheets-Sheet 2 Filed June l5. 1962 May 4, 1965 K. G. CLARK E'rAL 3,181,956

PACKAGING METHOD AND MACHINE Filed June 15, 1962 'T Sheets-Sheet 3 May 4, 1965 K. G. CLARK ETAL PACKAGING METHOD AND MACHINE '7 Sheets-Shed?I 4 Filed June 13, 1962 May 4, 1965 K. G. CLARK ETAL PACKAGING METHOD AND MACHINE 7 Sheets-Sheet 5 Filed June 13, 1962 May 4, 1965 K. G. CLARK ETAL PACKAGING METHOD AND MACHINE 7 Sheets-Sheet 6 Filed June 13, 1962 X ZOTFO m N 20:02 nl lli. \\\`& N s -lllw i- LL/ r May 4, 1965 K. G. CLARK ETAL 3,181,956

' PACKAGING METHOD AND MACHINE Filed June 13, 1962 7 Sheets-Sheet '7 United States Patent O 3,181,956 PACKAGING METHOD AND MACHINE Kenneth G. Clark, Homewood, Michael J. Myles,

Downers Grove, and Harry P. Eichin, Western Springs,

Ill., assignors to Union Carbide Corporation, a corporation of New York Filed June 13, 1962, Ser. No. 202,106 9 Claims. (Cl. 99-174) This invention relates to the art of packaging a group of assembled items in an envelope of ilexible film. More particularly, the invention is concerned with improvements in packaging whereby a preselected group of items, such as frankfurters, is encased Within an envelope comprising a tubular wall of elastic film that is tensioned about the encased items to form a tightly adhering shapecontorming wrap.

The invention provides a novel method of and means ttor substantially increasing the rate of lling elastic plastic bags yfor example, with preselected contents, the perimeter of which is greater than that of the bag to be iilled, while decreasing Waste due to 'bag breakage, Which comprises rst stretching the bag about %-20% more tha its original size, then heating and relaxing such bag, *further stretching the bag an additional amount about equal to such -iirst stretching, and iinal-ly filling the sofinally-stretched bag with such contents While releasing the bag into tensioned engagement therewith.

The invention further provides novel apparatus having lautomatically controlled means tor simultaneously cir- 'cumferentially part-ly expanding substantially the entire length of an elastic iilm bag, then heating and relaxing the bag .in a first step; lthen fully expanding and maintaining the bag in such expanded 'condition to a predetermined larger perimeter in a second step; means coordinated with said expanding means to convey the assembly of items to the mouth of the expanded bag, and insert the assembly of items into s-aid bag subsequent to its having been fully expanded, in a third step.

The invention also provides a novel method of packaging a plurality of generally similar elongated items arranged in side-by-side relation, which comprises holding such items in an open end support, applying on a stretcher an envelope comprising a tubular Wall of elastic plastic having a mouth which is smaller than the transverse dimension-s ot said members, stretching such tubular Wall, heating and relaxing the so-stre'tched Wall on said stretcher, again stretching the Wall to further enlarge such mouth, aligning such enlarged mouth with the items in such support, and pushing all of such items through the support and into the envelope through such enlarged mouth Vwhile simultaneously slipping the tubular wall `from p such stretcher, progressively shrinking the iilm about the sci-inserted items.

The main object of the invention is greatly to increase the production rate of packaging, while reducing substantially the volume of Waste due to breakage.

Another object is to provide for increasing the eiliciency and effectiveness of packaging of the kind herein involved.

Other objects will appear from the present disclosure.

A prior method of packaging is disclosed in U.S. Patent 2,884,328, E. O. Johnson. A packaging rate of only about 12 twodpound frankurter packages per minute, could be attained thereby. At such rate, the elastic bag had .to be fully expanded in a time interval of less than about 0,75 second.

Such frankfurter packaging opera-tions were normally carried on within a product ,cooler room maintained rat about 40 F. The cold environment or apparatus and product and the rapid stretching of the thin Walls and bottom closure of the elastic bags used in the operation,

adversely affected the utility of the bag, resulting in undesirable frequency ot" bag breakage.

According to the present invention, which is particularly adapted to the packaging of a rectangular -assembly of unit items as for example, two pounds ot `frankfurter Iproduct in a bag of elastic iilm to yield a package item wherein the frankfurters are tightly wrapped and snugly conformed Within .the Ibag Walls comprising the elastically stretched lm, the bag, Whose normal stretched perimeter is smaller than the maximum perimeter of the frankfurter items transverse to their longitudinal axes, is simultaneously elas-tically stretched circumferentially along substantially its entire length to ya larger perimeter than the assembled frankfurter items. The method of the present invention may be practiced at a packaging rate of about 25 two-pound frankfurter packages per minute. Such rap-id rate i-s attained by this invention Without adversely affecting bag breakage, by multistage expanding and relaxing of the bag walls, at a controlled rate, and by hearting the bag and the stretching linger-s, and by expanding the bag simultaneously circumlerentially along its entire length to a larger perimeter than the predetermined perimeter of the assembled frankfurters, and by advancing the product to the bag bottom to strip the bag from the expand-ed ngers at a controlled rate.

The novel method and apparatus of this invention packages irankfurters at twice the rate off 'the former method. `By controlled heating ot the bag and expanding lingers, by expanding-relaxing-expanding the bag in a multistage operation in a time interval three times longer, and by controlling the impact of product on the bag bottom closure and Walls as the bag is stripped from the lingers, the utility of the elastic bags used inthe operation is substantially improved.

`In the `accompanying drawings, likeV reference characters designate the same or similar parts in the various views, said drawings showing construction details and mode of operation of a typical apparatus embodying this invention and fw-herein:

FIGURE l is a front perspective View of Ian apparatus embodying the invention and generally showing assembled groups of ifranlcfurter product being conveyed to an elastic iilm bag stretched throughout its lengths by a set o'f parallel movably mounted stretching lingers.

`FIGURE 2 is a rear perspective view of the apparatus driving mechanism @coordinated tor conveying assembled groups or product to lan inserting station, for expanding and contracting tour sets of bag stretching lingers in parallel movement to each other, and rfor removing a lled bag trom a set of expanded `lingers While concurrently longitudinally elastcally stretching the bag over the product.

IFIGURE 3 is a rear elevation of the apparatus turret head with four sets ot parallel stretching lingers and internal cam mechanism coordinated for expanding and contracting four linger-formed passages.

FIGURE 4 is a fragmentary front elevation of the apparatus turret head with one set of parallel stretching fingers and associated operating means, in expanded position as indexed at a product loading station.

FIGURE 5 is a fragmentary front perspective of the apparatus at the product loading station with bag removed from the stretching lingers to show the product pusher plunger in retracted position.

FIGURE 6 is a front perspective of the internal cam in an alternate embodiment of the apparatus that cooperates with mechanism for successively partly-expanding then contracting, and then further expanding four lingerformed passages.

FIGURE 7 is a section along/the line 6--6 of FIG- URE 4.

FIGURE 8 is a fragmentary rear perspective of the apparatus at the product loading station with the product pusher plunger and associated operating means in retracted position, and indexed therewith a loaded product trough and bag stretched over an expanded finger-formed passage.

FIGURE 9 is a fragmentary front perspective of the apparatus at an intermediate station, With a partly expanded finger-formed passage indexed between a tandem heater unit.

FIGURE 10 is a fragmentary side elevati-on of the pusher plunger operating means.

FIGURE 11 is a front elevation of the pusher plunger.

FIGURE l2 is a diagram of the acceleration curve of the pusher plunger advance and retract motion.

FIGURE 13 is a schematic perspective of the apparatus drive and control means.

FIGURE 14 is an electrical wiring diagram of the apparatus.

The preferred embodiment of the improved packaging apparatus of this invention, as shown in FIGURES 1 and 2, comprises a rigid main frame 10, supported by attached legs 12; and a conveyor drive arrangement 14, for transporting assembled product items to a product loading station 6. A square turret head 16 is rotatably mounted on an intermittently operated horizontal driving shaft 18. Four sets of bag-stretching linger units A, B, C, D, are operably mounted at the extremities of the turret head diagonals. Each linger unit has an adjustably stationary linger mounting block 20, and a movable linger mounting block 22.

Finger unit A is successively intermittently rotatably indexed clockwise 90 at each packaging cycle from bag loading station 2 at three oclock position, whereat the lingers are retracted and an elastic film bag 24 is manually sheathed thereon, to intermediate station 4 at six oclock position. The movable linger 22 of unit A is slidably moved parallel inwardly from the stationary finger 20 along the turret head 16 diagonal (by means later described), as it is indexed from station 2 to station 4 (adjacent station 4, linger 22 is moved slightly outwardly), thereby partly expanding the bag 24 sheathed on the lingers 20, 22. At station 4, finger unit A has expanded the bag 24 to approximately 50% of the desired finished package perimeter.

At the next packaging cycle, linger unit A is rotatably indexed 90 from station 4, to product loading station 6 at nine oclock position, whereat lingers 20, 22 and the bag 24 sheathed thereon, are fully parallel expanded to a perimeter greater than that of the desired linished package. Refer additionally to FIGURES and 7. The product items 34 are previously assembled in a plurality of pr-oduct trough units 32, each fastened to roller chain conveyer 30. The product trough units 32 are successively indexed to station 6 where the product items are removed therefrom by a controlled acceleration pushing motion of plunger surface 40 transverse to conveyer 30, through the passage 28 formed by the expanded lingers 20, 22 to engage the stretched bag bottom. By continuation of the controlled motion of the plunger, the product strips the stretched bag from the linger-formed passage. At the next succeeding packaging cycle linger unit A is rotatably indexed 90 from station 6, to idle station 8 at twelve oclock position. At the succeeding packaging cycle, linger unit A is rotatably indexed from station 8 to return to station 2 at the three oclock position. As linger unit A is indexed successively through two package cycles to rotate from station 6 to station 2, movable linger block 22 is moved outwardly toward the stationary linger 20 along the turret head 16 diagonal to a contracted positi-on permitting the sheathing thereon of another elastic bag 24.

Finger stretcher units B, C, D, are similar to unit A and are respectively mounted and operated on turret head 16 in a like manner by like means. Conveyer drive arrangement 14 comprises a continuous horizontal chain conveyer 30 mounting a plurality of product troughs 32. Each product trough 32, preferably made of polished metal, is of a predetermined Width and height to cradle the desired number of frankfurters 34 to the perimeter of the desired finished package. The product troughs 32 are loaded with the desired number and/or weight of frankfurters, by several operators stationed along the conveyer remote from product loading station 6.

At each successive package cycle, a unit trough 32 loaded with product 34 is intermittently advanced and indexed central and opposite to the product loading station 6. A rectangular pusher plunger unit 38 with a perforate surface 40 of a perimeter less than the product trough 32 is slidable mounted central and opposite to loading station 6. When a linger unit such as A, and a product trough 32 are appropriately simultaneously indexed at station 6, the pusher plunger surface 40 is. advanced (as later described) to engage the product items assembled therein and slide them from the trough 32 through the expanded linger-formed passage 28 to engage the stretched bag 24 bottom, and continuing the advance, cause the encased product to strip the stretched bag completely from the -outside surfaces of expanded passage 28.

An electric motor 42, FIGURES 2 and 13, drives a V-belt drive 44 connected to a shaft-mounted speed reducer 46. The speed reducer 46 is mounted on main drive shaft 48 and braced to frame 10 by strut 50. On main drive shaft 48 is mounted a cam 52 for actuating an electrical switch 54 controlling an indexing interlock with the drive motor 42 (later described), a spur gear 56 mating with spur gear 58 for driving intermittently indexing drive unit 60, and bevel gear 62 mating with bevel gear 64 fastened to shaft 65, driving product pusher face cam 66.

The intermittent rotation of the output of indexing drive 60 is directly connected by coupling 61 to turret head drive shaft 18, on the outboard end of which is affixed the turret head 16. Refer additionally to FIGURE 8. Intermediate the turret head 16 and drive unit 60 on shaft 18, is mounted sprocket 68, that drives continuous roller chain 70 mating with sprocket 72 that is mounted on conveyer shaft 74. Two spaced sprockets 76, 76', also mounted on shaft 74, drive parallel spaced continuous roller chains 78 to which are outwardly aliixed a plurality of product troughs 32.

Referring now to FIGURES 2, 3, 4, internal surface cam 80 is aixed to bracket 82 and thereby to frame 10. Internal surface 86 of cam 80 is of a generally ovate contour shaped to rapidly expand the bag 24 loosely sheathed on the linger unit at station 2 at the beginning of a` packaging cycle, as one of the four bag stretching units such as A, is rotated from station 2 to station 4. Cam 80 is fixedly mounted to frame 10 with its major axis horizontal and eccentric to the centerline of shaft 18. Cam followers 84 are slidably mounted on turret head 16 to operate radially to the axis 18 and parallel to the diagonals of head 16, and are resiliently urged against the contoured inner surface 86 of cam 80. As the turret head 16 is intermittently rotatably indexed, cam followers 84 linked to respective movable linger blocks 22, govern the relative displacement of movable linger blocks 22 coordinated to expand and contract the four linger-formed passages. When the turret head 16 moves from station 2 to station 4, cam follower 84 follows the cam contour 86, and linkage connecting the movable linger thereto partly expands the bag sheathed on the lingers.

In an alternate embodiment, the machine is provided with the linger-expanding internal cam 81 shown in FIG- URE 6. Internal surface 86 of cam 81 is of a generally about the finger-formed passage. Immediately prior to termination of the cycle, cam follower 84 is urged into depression 87 thereby slightly contracting the finger-formed passage and permitting the walls of the partly-stretched bag to relax about the surfaces of the stretching fingers thereby equilibrating the stresses in the partly stretched bag walls prior to the heating thereof.

Each cam follower 84, FIGURES 3 to 7, is affixed to a grooved slide block 88, slidably mounted in parallel guide ways 90 affixed to turret head 16, and operating in slot 91 cut through the turret head. The cam follower 84 operates adjacent the back surface of turret head 16, coordinating the motion of slide block 88, slidably mounted on the front surface of the turret head 16. Connecting rod 92 rigidly fastens slide block 88 to movable finger block 22 spaced outwardly therefrom. Each of the finger blocks 22, is slidably mounted on parallel slide rods 94 equally spaced about the centerline of the diagonals of turret head 16. The inboard end of rods 94 are rigidly fastened into L-shaped brackets 96, that are aiiixed to the front surface of turret head 16. An intermediate portion of rods 94 is supported by adjustable stop brackets 96, that are adjustably, slidably fastened to the front surface of turret head 16 by suitable fastening means engaging slots 100.

The outboard end of rods 94 adjustably, slidably support the extremities of stationary finger block 20. Cornpression springs 102 slidably supported on rods 94 intermediate the surfaces of brackets 96 and block 22, resiliently urge the movable finger block 22 outwardly, limiting its outward movement -by contact with stop brackets 96. Operation of cam follower 34 on contoured surface S6 by means of the connecting linkage described, urges the movable finger block 22 inwardly thereby compressing springs 102 and expanding the elastic bag sheathed on the fingers. The fingers are closed to contracted position by resilient pressure of springs 102, thus insuring a safe manual operation in sheathing the bag on the fingers.

The finger blocks 20, 22, FIGURES 4, 5, 7, are provided with slide ways 106 machined to mate with grooves provided in finger brackets 104, S that are respectively adjustably fastened thereto. Thus, the position of the lingers may be adjusted radially and centrally with respect to the turret axis 1S and thereby provide means to align the axis of the expanded finger-formed passage 28 with the axis of the pusher unit 38 at product loading station 6.

Finger brackets 104, 105 are similarly machined with a groove that mates with the tongue 108, of finger blades 112, 114. Finger blades 112, 114 are fastened to brackets 104i, 105 by a ball detent holding pin 110. This arrangement permits a ready and quick interchange of finger blades of different shapes contoured to different product assembly shapes onto mating finger blocks. The stationary finger comprises an arcuate shaped, extended metal finger blade 112 preferably having smooth polished surfaces to avoid abrasion and/or tearing of the bag film and product items, and having sanitary surfaces as for example stainless steel or chromium plated surfaces. The movable nger blade 114 similar in shape and length to stationary finger blade 112, is provided with a t'op and bottom skirt 116 that is an extension of the arcuate upper and lower finger blade edges having a length approximately 1/3 the blade length and width suiiicient to bridge the passage 2t? formed by the blades 112, 114 in expanded position.

Skirt 116 bridges or spans that portion of the passage intermediate product trough 32 and the mouth of expanded bag 24 to prevent the product items from being dropped through the open fingers or from being snagged or caught by the bags expanded mouth.

Pusher unit shown generally as 33, FIGURES 8, l0, is intermittently, reciprocally operated at controlled acceleration and deceleration rates to contact and advance a plurality of fragile nested resilient food product items 341 from product trough 32, centrally to and through expanded finger-formed passage 23 to conform snugly to f5 the bag 24 bottom, without damage, and to encase the product in the stretched bag concurrently as the encased product is stripped completely from the expanded fingers.

The pusher unit 3E intermittently advances and retracts during the dwell portion of the cycle of indexing drive 60. The necessary speed of operation, cushioning action for the product and complete removal of the filled bag by the pusher plunger, is obtained by constant rotation of face cam 66. Refer now to FIGURE 12, representing a graph of the face cam 66 angular displacement, plotted against displacement of the pusher 38 plunger through linkage shown on FIGURE l0 (later described).

The cam contour groove 119 and associated linkage provi-des a 120 dwell with the pusher plunger in retracted position. As the face cam rotates the next 'the cam groove 119 advances the pusher by cycloidal accelerated motion X, and in the next 40, advances the pusher by harmonic decelerated motion Y. As the cam rotates the next the cam groove 119 retracts the pusher by harmonic accelerated and decelerated motion Z."

Pusher unit 38 has a skirt 118 ciroumscribing the perimeter of surface 40. Skirt 118 is of a length greater than the space intermediate the pusher surface 40 in its furthest advanced position and the outboard extremities of the expanded finger blades 112, 114, and serves to guide the bag-encased product from the fingers and preveut collapse of the bag walls trailing the encased product. The pusher plunger front surface 40 is perforated with a plurality of holes 41 to relieve air pressure in the bag caused by the product advance therein and by the vacuum otherwise created by the plunger return stroke. Vacuum caused by a return stroke can `dislodge a product unit item from snug contact with the bag bottom and extract it from the package.

The cam groove 119 mates with cam follower 120 that is afiixed to connecting rod 122 intermediate its fulcrum bearing 12d rotatably fastened to frame 10, and clevis crosshead 12d. Clevis crosshead 12.6 is fixedly fastened to pusher drive rod 123 that fixedly mounts pusher plunger 35 at one extremity and slide block 130 at the other extremity of drive rod 12S. Parallel guide rods 132, 132 are equally spaced about the centerline of rod 128 that determines the axis of product loading station 6, and are afiixed in guide rod blocks 134, 13rd fastened to frame 1u.

As shaft e5 rotates continuously, the cam groove contour advances and retracts pusher drive rod 128 through forward bearing 137 in block 136, the other end of drive rod 123 being guided by block 130 sliding on rods 132, 132. Pusher plunger 38 thereby cooperates with the product in previously indexed product trough 32, and the finger-formed passage of an expanded finger unit such as A, aligned with the pusher plunger longitudinal axis.

Another important feature of the apparatus, FIGURES 3, 9, provides for the heating of finger blades 112, 114 and the partly expanded elastic bag 24 at stations 8 and d. Tandern curvilinear electrical resistance heater units are positioned central of stations 4 and 8, and are comprised of two 200 watt curved heater elements. An upper heater element 13S and lower heater element 140 are fastened onto electrical connecting boxes 139, 139 in turn affixed to bracket 142 mounted on frame 10. Heaters 138, 1410 at stations 4 and are spaced apart respectively, a distance approximately 1/2 greater than the span of the partly expanded finger blades at each of said stations. Electrical current for the heat elements 13%, 1li-0 is provided by wires 14d, 144.

The electrical control system for the apparatus drive is shown in FIGURES 13 and 14. At routine starting and stopping of the apparatus, it is desirable that the turret head 16 be indexed to the dwell portion of a cycle that the pusher plunger is in retracted position. Closing the Lstart button of push button station 146 closes control relay 148 that in turn closes contactor motor starter `generally shown as 150, energizing motor 42 with line voltage L1L2L3. The magnetic hold-in 152 of the starter 150 is in series with cam limit switch 54 and control relay 148. Cam switch 54 is opened by the depression in cam 52 when turret head 16 is indexed to dwell position. When the stop button of push button station 146 is opened, relay 14S opens, but starter hold-in 152 keeps the starter 15) contacts closed, until cam switch S4 opens, thereby opening the hold-in circuit 152, and the starter 150 contacts open and motor 42 stops.

For operator safety, a normally open foot pedal switch 154 is provided that is a master control on the lun circuit and must be depressed at all times to maintain operation. Foot pedal switch 154 is in series with L1 and the stop side of push button station 146, and when switch 154 is released to open, the hold-in circuit of starter is immediately broken and the starter 15) contacts open and motor 42 stops.

Another embodiment of the apparatus is particularly adapted to the packaging in flexible film bags, of long length product items such as foot-long frankfurters, meat loaves, and the like. This embodiment is provided with two independently operated pusher plunger units; a primary pusher positioned central to station 6 and a secondary pusher positioned central to station 8. Machine components of this embodiment are similar to those shown in FIGURES l and 2 of the preferred embodiment and operate in a like manner. A square turret head 16 mounts four sets of elongated bag-stretching finger units A, B, C, D, intermittently indexed to four stations 2, 4, 6, S, as described supra. The finger-formed passages are successively indexed to the bag loading station 2 (retracted passage) at the three oclock position, and thence to intermediate station 4 (partly-expanded passage at the six oclock position by means disclosed in the appzrratus of the preferred embodiment. However, at product loading station 6 (fully-expanded passage), nine oclock position, the primary pusher assembly is arranged to advance the product items from trough units 32 fully into the expanded finger-formed passage, but not to strip the bag therefrom. The product items thus are held within the expanded bag-encased finger-formed passage at station 6 and advanced therein to station 8. A secondary pusher unit is aligned with station 8. The secondary pusher unit is coordinated to advance the product items through the passage to the bag bottom and strip the bag from the expanded finger-formed passage. The next cycle, advances the finger-formed passage to station 2, where the fingers are retracted to receive another bag. This mode of operation permits advancing the primary pusher unit only the length of the product at station 6, thereby deferring for the next cycle of operation the time required to strip the bag from the fingers, by the secondary pusher unit positioned at station 3. Thus, dwell time of the machine is not adversely affected by bag packaging of elongated product items, since a two-step dofiing action is provided for loading the product into the expanded finger-formed passage in a first step at station 6, and stuffing the product in a second step at station 8.

The following is an illustrative example of the operation of the preferred embodiment of the apparatus. Eighteen franks Weighing 11/2 pounds are nested in generally parallel relationship as a substantially rectangular prism in product troughs 32 with the machine set to operate at cycles per minute. A 51/2 fiat width (11" circumference) Visten pouch bag (of seamless plasticized polyvinyl chloride film) is sheathed on the finger-formed passage retracted to 9" perimeter at station 2. During the first cycle, the bag is partly stretched to 13 perimeter, at station 4 during the turret head 16 dwell period. While at station d, the bag is heated by the tandem electrical heaters 133, 14@ to about 45 F. over the ambient temperature. This elevated tempera- 8 ture improves the stretch characteristics of the film and promotes removal of the bag-encased product from the stretching fingers. During the next cycle, the bag is fully stretched to a 15" perimeter at station 6.

It will be understood that the stroke of the pusher is of such extent and is so correlated with the operation of the machine that the entire contents of the trough is pushed into the bag until such contents reaches the bottom of such bag, and thereby pushes and strips the sofilled bag progressively from the fingers holding the bag in fully stretched condition, and such pusher is thereupon fully retracted from the so-filled bag and into position for another stroke.

As will be understood from the foregoing disclosure, an important feature of the present invention is what may be termed equilibration or equilibrating of cold film on the stretcher between the start and finish of the overall stretching operation. This is accomplished in one or more of the steps comprising: the pause or delay in the overall stretching of the film; heating of the film and stretcher-fingers to condition favorably the film for further stretching after it has first been at least partially stretched; and relaxing the film by slightly contracting the stretching fingers, thereby permitting it to rearrange itself on the fingers of the stretcher during such pause or delay in the overall stretching process.

As used herein, the term film is not necessarily limited to but includes: plasticized polyvinyl chloride films; synthetic rubber films; cellulosic films; polyolefin films such as polyethylene and polypropylene, and the like.

What is claimed is:

l. Method of packaging a plurality of elongated items arranged in side-by-side relation, which comprises holding such items in an open end support, applying on a stretcher an envelope comprising a tubular wall of elastic film having a mouth which is smaller than the transverse dimensions of said members, stretching such tubular wall, heating said film and relaxing the wall by slightly retracting said stretcher, again stretching the wall to further enlarge such mouth, aligning such enlarged mouth with the items in such support, and pushing all of such items through the support and into the envelope through such enlarged mouth while simultaneously slipping the tubular wall from such stretcher, whereby said film progressively shrinks about the so-inserted items.

2. Method of filling elastic film bags with contents the perimeter of which is greater than that of the bag, which comprises first stretching the bag about l5%-20% more than its original size, then relaxing by slightly releasing the stretching power on such bag, further stretching the bag an additional amount about equal to such first stretching, and finally filling the so-finally-stretched bag.

3. Method of packaging a plurality of frankfnrters arranged in side-by-side relation, in a wrapper of elastic film, which comprises transversely stretching a bag composed of such film having a bottom and side walls providing a mouth that is smaller than the transverse dimensions of suoli frankfurters, with parallel preheated fingers extending into the bag, by moving such fingers away from one another to a limited extent, relaxing the so-stretched film by simultaneously retracting said fingers toward one another to an extent less than that of such film stretching movement, and further stretching the sorelax'ed film by again moving such fingers away from one another to an amount at least equal to the first stretching, inserting frankfurthers through the so-enlarged mouth into the bag and against the bottom thereof to push the sofilled bag away from said fingers as the film contracts into engagement with the frankfurters.

4. Method of packaging items in a bag of elastic film to yield a package wherein the items are tightly wrapped and snugly conformed within the bag walls of the elastically stretched film, said bag, whose normal unstretched arenoso perimeter is smaller' than the maximum perimeter of the items transverse to their longitudinal axis, is simultaneously elastically stretched circumferentially along substantially its entire length to a larger perimeter than the assembled items, at a packaging rate of the order of packages per minute, which comprises multistage expanding and relaxing by slightly releasing the stretching power on the bag walls with stretching lingers, at a controlled rate, heating the bag and the stretching fingers, and expanding the bag simultaneously circumferentially along its entire length to a larger perimeter than the predetermined perimeter of the assembled items, and finally filling the bag by advancing the product to the bag bottom to strip the bag from the expanded fingers at a controlled rate.

5. A packaging machine comprising, in combination, means for partially stretching an elastic film bag While indexing such bag from a loading station to a relaxing station, means acting to automatically relax the so-partially stretched bag in its partially stretched condition and simultaneously heat it, means for fully stretching the bag while indexing it to a content-filling station, and means for filling the so fully stretched bag and removing the so-lled bag from such content-filling station, so that the bag compresses the contents thereof.

6. Automatic packaging apparatus comprising, in combination, a rotary turret head provided with four stations each comprising elastic film bag supporting fingers, such stations consisting of a bag applying station, a bag heating and relaxing station, a product loading station, and a finger heating station, means for indexing said head through 90 increments, means for automatically moving such lingers away from each other to partially expand and stretch the bag thereon as the turret head is indexed to advance each bag from such bag applying station to said bag heating and relaxing station, means for maintaining the spacing of such partially expanded fingers at such bag heating and relaxing station during the dwell period and simultaneously heating such bag, means acting to again move the fingers further away from each other as the head is indexed to advance the so-relaxed bag from said bag heating and relaxing station to` said product loading station, a plurality of product trough units, means for successively advancing said product trough units in line with the mouth of each bag as the latter is positioned at said product loading station, means for pushing products successively from such units transversely into such sostretched bag and simultaneously stripping the so-illed bag from the fingers holding the so-stretched bag open, and automatically retracting such fingers as the head is indexed to move them from such product loading station to the finger heating station.

7. Method of packaging as defined by claim 3, which includes pushing the frankfurters from a trough supporting them in generally parallel relation as a substantially rectangular prism into the stretched elastic-film bag positioned in alignment with such frankfurters in said trough to receive them which 4comprises pushing all of such frankfurters gently at first and then more rapidly into Such bag and against the bottom thereof, Venting air thereby compressed in the bag therefrom, whereby damage to such frankfurters and the bag is minimized during substantially high-speed operation.

S. The method defined in claim l which comprises the additional step of radiantly heating the stretcher on which the envelopes are applied prior to applying the envelopes to heat soften and thereby favorably condition the film for subsequent stretching thereon.

9. rEhe method defined in claim 1 which comprises the additional step of simultaneously heating both the film and the stretcher after the envelope is at least partially stretched thereon to warm and thereby favorably condition the iilrn for further stretching.

References Cited by the Examiner UNITED STATES PATENTS 2,289,663 7/42 Mallory 53-30 2,312,049 2/43 Pfeiffer 53184 X 2,331,762 itl/43 Brown 53-30 2,884,328 4/59 lohnson 99-171 2,955,941 1G/ 6() Hultkrans et al. 99-171 2,958,168 1l/6O Vogt 53-184 X 3,022,543 2/62 Baird et al. 99-171 3,031,309 5/62 Muskat et al. 53-184 X A. LOUIS MONACELL, Primary Examiner.

ABRAHAM H. WINKELSTEIN, RAYMOND N.

JONES, Examiners.

Claims (2)

1. 2. METHOD OF FILING ELASTIC FILM BAGS WITH CONTENTS THE PERIMETER OF WHICH IS GREATER THAN THAT OF THE BAG, WHICH COMPRISES FIRST STRETCHING THE BAG ABOUT 15%-20% MORE THAN ITS ORGINIAL SIZE, THEN RELAXING BY SLIGHTLY RELEASING THE STRETCHING POWER ON SUCH BAG, FURTHER STRETCHING THE BAG AN ADDITIONAL AMOUNT ABOUT EQUAL TO SUCH FIRST STRETCHING, AND FINALLY FILLING THE SO-FINALLY-STRETCHED BAG.
2. 5. A PACKAGING MACHINE COMPRISING IN COMBINATION, MEANS FOR PARTIALLY STRETCHING AN ELASTIC FILM BAG WHICLE INDEXING SUCH BAG FROM A LOADING STATION TO A RELAXING STATION, MEANS ACTING TO AUTOMATICALLY RELAX THE SO-PARTIALLY STRETCHED BAG IN ITS PARTIALLY STRETCHED CONDITION AND SIMULTANEOUSLY HEAT IT, MEANS FOR FULLY STRETCHING THE BAG WHILE INDEXING IT TO A CONTENT-FILLING STATION, AND MEANS FOR FILLING THE SO FULLY STRETCHED BAG AND REMOVING THE SO-FILLED BAG FROM SUCH CONTENT-FILLING STATION, SO THAT THE BAG COMPRESSES THE CONTENTS THEREOF.

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