US3272113A

US3272113A - Power strapping machine and the like and adjustable feeding and tensioning means therefor

Info

Publication number: US3272113A
Application number: US418039A
Authority: US
Inventors: Howard K Otto
Original assignee: Signode Corp
Current assignee: Signode Corp
Priority date: 1964-12-14
Filing date: 1964-12-14
Publication date: 1966-09-13
Anticipated expiration: 1983-09-13

Description

H. K. OTTO 3,272,113 HINE AND THE LIKE AND ADJUSTABLE TENSIONING MEANS THEREFOR Sept 13, 1966 5 Sheets-Sheet 1 POWER STRAPPING MAC FEEDING AND Filed Dec. .14, 1964 NvENToR HOWARD K. OTTo AT'rYS.

H. K. oTTo 3,272,113

ADJUSTABLE SIGNING MEANS THEREFOR Sept. 13, 1965 POWER STRAPPING MACHINE AND THE LIKE AND FEEDING AND TEN Sheets$heet 2 Filed Dec. 14, 1964 INvEN'roR Howmw O'r'ro M {M 3272 113 STABLE H. K. OTTO HINE AND TH Sept. 13, 3966 E LIKE AND ADJU ENSIONING MEANS THEREFOR POWER STRAPPING MAC FEEDING AND T 5 fiheets-Sheet 5 Filed Dec. 14, 1964 United States Patent POWER STRAPPHNG MACHINE AND THE LIKE AND ADJUSTABLE FEEDING AND TENSIUNIN G MEANS THEREFOR Howard K. Gtto, Berkeley, 11]., assignor to Signode Corporation, Chicago, 111., a corporation of Delaware lFiled Dec. 14, 1964, Ser. No. 418,039

18 Claims. (Cl. 100-46) The present invention relates to power strapping machines for binding bundles, packages, coils and similar articles with loops of flat tensioned straps and the like with overlapping ends united in a tension resisting joint. Particularly, the invention relates to a power strapping machine of the class described wherein the pressure with which the strap is gripped by the machine is controlled in accordance with the tension in the strap during the feeding and tensioning of the strap.

Machines of the class referred to herein operate automatically or semi-automatically to pass a length of strap about a bundle with the free end of the strap placed in overlapping position with the standing portion thereof. The standing portion of the strap is that part connected to a source of strap supply such as a reel or coil thereof. The free end of the strap is gripped and then the standing portion is withdrawn so that the loop of strap is shrunk closely down about the bundle as a proper or selected tension is applied thereto by the machine. When the tension has reached a satisfactory value, the overlapping portions of the strap and an embracing seal are crimped together and united into a tension resisting joint; and the strap applied to the bundle is severed from the source to provide a strapped article.

In a machine of the described class, the operations of feeding or passing of the strapping segment about the bundle and thereafter tensioning the strap employ the same components which are driven in different directions to perform the two functions. Generally employed for the purpose are a pair of opposed wheels between and by which the strap is fed in one direction into binding position and by which the strap is pulled in an opposite direction for tensioning same.

During the tensioning operation, at least one of the wheels positively draws the strapping by frictional engagement thereof or by biting the strapping with peripheral teeth. In the course of each strap tensioning operation as the strap segment about the bound article shortens, the requirement for torque to pull or tension strap gradually increases as the resistance to the tensioning gradually increases. Therefore, it is desirable to have applied to the strap a gradually increasing force of sufficient magnitude to overcome the increasing resistance to the tensioning until the desired tension level is reached.

With prior devices, frequently, before desired tension is achieved, the resistance in the applied strap to the pulling in reverse feed or tensioning direction by the opposed wheels becomes greater than the torque applied frictionally to pull the strap. As a consequence of the foregoing, any wheel driven to tension the strapping will have a tendency to slip with a consequent undesirable erosion of the strap and of bearings of the shaft providing an axis of rotation for each driven wheel.

The instant invention overcomes this problem and provides a new and improved strapping machine adapted automatically and gradually to adjust the pulling force on the strap in proportion to the increase in resistance therein during tensioning. To accomplish this, machines embodying this invention are provided with an improved feeding and tensioning mechanism which incorporates a driven eccentric adapted to multiply the torque of the prime mover and enhance the force with which the strapping being tensioned is gripped between the wheels.

3,272,113 Patented Sept. 13, 1966 These and other features and advantages of the present invention will become apparent upon consideration of the following description and appended claims, when considered in conjunction with the accompanying drawings, which form a part of this specification, wherein the same reference character or numeral refers to like or corresponding parts throughout the several views, and in which:

FIGURE 1 is a side elevational view of a power strapping machine embodying the improved feeding and tensioning mechanism;

FIG. 2 is an end view of one embodiment of the improved feeding and tensioning mechanism, with parts broken away to illustrate various other parts;

FIG. 3 is a sectional view taken substantially on the line 33 of FIG. 2 and looking in the direction of the arrows;

FIG. 4 is a sectional view taken substantially on the line 4-4 of FIG. 3 and looking in the direction of the arrows;

FIG. 5 is an end view of a modified embodiment of the feeding and tensioning mechanism, with parts broken away to illustrate various other parts; and

FIG. 6 is a sectional View taken substantially on the line 66 of FIG. 5 and looking in the direction of the arrows.

There is illustrated in FIG. 1 a power strapping machine which is provided with a frame lli on which there is mounted a prime mover means shown as a reversible electric motor 11 or the like, a motor housing flange 20 of which is suitably secured by fasteners such as bolts 13 to the frame.

The drive shaft of the motor 11 operably connects with a pinion 12, as illustrated in FIG. 3. On an end portion thereof pinion 12 carries a spiroid gear head 14 for which said pinion provides a fixed axis of rotation. The pinion 12 is suitably journalled, for example, in ball bearings 15.

Prime mover force is transmitted through the gear head 14 to drive a strap feeding and tensioning mechanism designated generally as numeral 16 in FIG. 1. The details of construction of one form of the strap feeding and tensioning mechanism 16 are shown in FIGS. 2, 3 and 4. The details of construction of a modified form thereof are shown in FIGS. 5 and 6.

With respect to the system shown in FIG. 1, mechanism 16 feeds strap S to the left and tensions strapping S to the right. Strap S passes through a pair of

path providing guides

17 and 18, each of which comprises a pair of spaced apart plates disposed behind a cover plate 33. The guide 17 is disposed on the tension side of the mechanism 16 and the guide 18 is disposed on the feed side of mechanism 16.

The strap S is fed during operation of the power strapping machine from guide 18 and through a closed guide, track or chute 19 about a therein provided bundle receiving opening 21. The guide, track or chute 19 provides a path directing the leading edge S of the strap into overlapping relationship with the standing portion S" of the strap adjacent the joint-forming mechanism not clearly shown in the drawings.

In the illustrated machine there is provided an abutment 23 against which the leading edge S of the strapping is guided to stop further movement thereof. When this happens, the feeding drive of the motor 11 continues, but track 19 is provided with a spring biased drop-out section or jaw 24 so that the fed strap which can no longer advance will build up force in chute 11. That will cause jaw 24 to ultimately pivot against action of its spring 23 to permit the excess strapping to balloon outwardly, as illustrated in dotted lines in FIG. 1.

As the jaw of drop-out section 24 pivots downwardly it engages and rotates a spring biased plate 25 into engagement with lever 26 of switch 27. Switch 27, which is suitably mounted upon an accessible portion of the frame in any conventional manner, is operably connected to the reversible motor 11. When the switch lever 26 is moved under the action of the depressed plate 25, as aforedescribed, the motor 11 reverses its drive to begin the tensioning operation.

As the tensioning operation progresses, that is, as S moves to the right with respect to FIG. 1, the ballooned strap section will be returned to chute 19; and under the action of spring 28, jaw portion 24 will be urged back to its normal track position.

At the conclusion of the tensioning operation the jointforming operation occurs. A seal is applied about the overlapped leading edge S and standing portion S", and when the tensioning operation has been completed the seal is crimped about such overlapped strapping.

To the end that a seal will be formed by the machine, an open ended seal magazine 29 therewithin adapted to hold a plurality of metal seal blanks in stacked fashion is suitably carried upon the frame 10. A follower member 30 urged to the left with respect to FIG. 1 by spring 31 keeps a constant pressure on the stack of seals in the magazine 29. The exit end of the seal magazine 29 is obscured in FIG. 1 by a bracket 32.

The mechanism for removing the seals one at a time from the magazine 29 as well as the mechanism for applying and crimping the seal and for severing the standing end S of the strap are not shown in detail. They may be of any suitable type such as that disclosed in US. Patent No. 2,915,003, issued December 1, 1959.

Referring now more particularly to the feeding and tensioning mechanism 16, which is shown in detail in FIGS. 2, 3 and 4, attention is invited to its plate or cover 33 which is secured by appropriate fasteners such as screws, bolts 34, or the like to an accessible portion of frame 10, and it has a centrally disposed aperture 40. The cover or plate 33 has an inwardly extending annular flange 35, the outer diameter of which is less than the outer diameter of the plate or ring 33. Accordingly, an annular shoulder 36 is generated which abuts against a fiat surface 37 provided by the frame 10. An annular slot 38 provided in the flange at its juncture with or point of departure from the cover of plate 33 provides a Well for a sealing or O-ring 39 which seals the plate or cover 33 to the frame member 10, as illustrated in FIG. 3.

There is a bore or opening 41 in the frame 10 into which the flange 35 extends. The hub 43 of a spiral or spiroid gear 44 extends toward the cover or plate 33 and is centrally disposed within the bore 41 whereby the axis of rotation of said gear 44 is coincident with the longitudinal axis of bore 41. The spiral or spiroid gear 44 meshes with gear head 14 to thereby transmit prime mover force to the spiroid gear 44.

The bore or opening 41 is enlarged to provide an annular shoulder 42. At the juncture of the spiroid gear ring 44 with its hub 43, an annular shoulder 45 is provided in operative alignment with the shoulder 42. The aligned shoulders 42 and 45 provide an abutment for the annular race of a ball bearing 46 in which the hub 43 is journalled. A snap ring 47, which is seated in annular groove 48 formed in the hub 43, acts as a retainer by engaging against the race of ball bearing 46 to hold the same against the shoulders 42 and 45 in the manner illustrated in FIG. 3 of the drawings.

An inwardly disposed annular shoulder 49 is provided by the cover or plate 33. The shoulder 49 provides an abutment for the annular race of ball bearing 50. Ball bearing 50 is spaced from ball bearing 46 and provides a journal for the inner end portion of the gear hub 43. Ball bearing 50 is retained in abutment with the shoulder 49 by means of a spacer 51, the opposite surfaces of which bear against the facing parts of bearings 46 and 50 in the manner illustrated in FIG. 3.

The spiroid gear 44 and hub 43 thereof have a centra-lly disposed aperture or opening 52. A spur ring gear comprising a plurality of internal spur or inwardly extending radial teeth 53, only several of which have been labeled in FIG. 4, are fabricated preferably integral with the spiral or spiroid gear 44 and extend into opening 52. Teeth 53 mesh with the outwardly extending or radial teeth 54 of a planet spur gear 55. The radius of the planet spur gear 55 is less than the radius of the internal spur ring gear by reason of which the torque transmitted from the shaft 12 through the gear 14 through the gear teeth 53 to the gear 55 will tend to drive the planet spur gear 55 eccentrically in the bore or opening 52 in which said spur planet gear is disposed.

The spur gear 55 is integral with or rigidly secured on a stub shaft 56 which provides the axis of rotation for the spur planet gear 55. The axis of rotation of the stub shaft 56 extends longitudinally of the axis of rotation of spiroid gear 44. However, the disposition of the axis of shaft 56 is eccentric with respect to the bore or opening 41; and the shaft 56 extends eccentrically through the opening or aperture 40 in the cover or plate 33, for a reason which will be apparent hereinafter.

A toothed traction wheel 57 is rigidly secured on an outer end portion 58 of the shaft 56. The securance can be achieved suitably by keying or splining as shown at 59. Such construction insures rotation of the traction wheel 57 with the shaft 56.

To preclude outward displacement of the traction wheel 57 longitudinally of the shaft 56, a removable retaining split clamp or ring 60 is mounted in an annular peripheral groove 61 formed in the outer end portion 58 of the shaft 56. An outer peripheral extension 62 of the clamp or split ring 60 extends outwardly from groove 61 and bears against the outer end face 63 of the hub 64 of the toothed traction wheel 57.

The split ring or clamp 60 has a pair of apertured ears or lugs which are disposed in opposed positions, as illustrated in FIG. 2. By means of a suitable tool, not shown, the split ring or clamp 60 may be mounted or removed according to requirements.

To preclude inward displacement of the toothed traction wheel 57 longitudinally of the shaft 56, a pair of shoulders 66 and 67 are provided on the shaft end portion 58 in longitudinally spaced apart relationship by external diametric reductions. The shoulders 66 and 67 are engaged by corresponding interior abutting surfaces formed in the bore 22 of the toothed traction wheel 57, as illustrated to the left in FIG. 3.

The toothed traction wheel 57 has a plurality of integral peripheral teeth 68 which are adapted to bite into the strap S whereby the strap S may be fed or tensioned according to the direction of the torque applied on such strap by the traction wheel 57. The traction wheel 57 is substantially as wide as the strap S whereby there is a maximum application of the driving torque to the strap S.

The back up wheel or pressure roller 69 is disposed in operative alignment with the toothed traction wheel 57, as illustrated in FIG. 2. The back up wheel 69 engages the strap S on a side opposite to the traction wheel 57 to maintain the strap in engagement therewith to insure that the strap S is fed or tensioned according to the direction or rotation of the shaft 56. The back up wheel or pressure roller 69 rotates on a fixed axis of reaction which is provided by shaft 70. The shaft 70 is suitably journalled in an accessible portion of the frame 10 and cover or plate 33.

The shaft 56 is centrally journalled within the passage :or bore 72 of a rotor 71. The rotor 71 is itself rotatably mounted in the bore 52. The bore 72 of the rotor 71 is disposed eccentrically therein as clearly illustrated in FIGS. 2 and 3.

The means for journaling the rotor 71 which is centrally disposed within the bore 52, comprises a pair of

needle bearings

73 and 74 which are disposed longitudinally of the shaft 56 about the rotor 71 against the inner surface of the hub 43. These

bearings

73 and 74 are held in spaced apart relationship by means of spacer 75, the opposite annular ends of which bear against facing portions of the races of the

bearings

73 and 74. At one end the eccentric 71 bears against one face of a washer 76 which also serves to prevent displacement of the

bearing

73 and 74 by engagement with a portion of the race of bearing 73 in the manner illustrated in FIG. 3. The opposite face of the washer 76 bears against an annular shoulder 77 formed at the juncture of the shaft 56 with its gear 55. The washer is centrally apertured and disposed about the shaft 56 in the manner illustrated in FIG. 3.

Longitudinal displacement of the rotor 71 in the direction of the traction wheel 57 is precluded by means including a rotor flange or cap 78. The rotor flange or cap 78 is mounted in the aperture 411 of the plate 33 and it is connected to rotor 71 by means to be hereinafter described. The plate 78 is fabricated from any suitable bearing metal such as bronze and the like for a reason which will become apparent hereinafter.

Rotor flange or cap 78 has an eccentrically disposed aperture 79 which is in longitudinal axial alignment with the bore or passage 72 in the rotor 71 whereby said aperture 79 accommodates the shaft 56. An 0 or sealing ring 30 which is mounted in a peripheral annular groove 81 in the flange 78 acts as a seal of said plate in the mounting cover plate 33, as illustrated in FIG. 3. A ring 32 is mounted in an annular recess 83 in said flange 78 about the shaft 56 and functions to seal the opening between said flange 78 and sai shaft 56.

The flange 78 has an inner shallow pan-shaped enlarged recess in which the outer end portion 84 of the rotor 71 is mounted to bring the adjacent faces thereof into abutment along an apertured flat 85.

Flange 78 on an inner surface is formed with a radial flange 86 which is disposed against the inner surface of the cover 33 about the opening 40 as illustrated in FIG. 3. The height of flange 86 is suflicient to provide an abutment for the shaft 43 and also for the outer surface of the race of bearing 74 whereby displacement of the

bearings

73 and 74 toward the traction wheel 57 is preeluded.

To journal the shaft 56 there are provided a plurality of annular bearing members 87, only some of which have been numbered in FIGS. 2 and 3. The bearing members 37 are spaced from each other longitudinally of the shaft 56, and they center the shaft 56 in the

apertures

72 and 79. At one end the bearings 87 are retained by engagement with the washer 76 as illustrated in FIG. 3; and at the opposite end the bearings 87 are retained from displacement longitudinally of shaft 56 by means of the flat 85 provided by the flange 78.

For further locking the parts from undesired displacement there is provided a split ring 38. The inner annulus of the split ring 88 is angular in cross section as illustrated in FIG. 3. The ring is accommodated in a peripheral groove of corresponding angulation which is formed in the shaft 56 adjacent the flange 78 medially thereof and the traction wheel 57, as shown at $9 in FIG. 3. A split ring or clamp 99 having a pair of opposed apertured ears or lugs 91 is mounted in a peripheral slot provided therefor in the split ring 98. By means of a conventional tool, not shown, the ring or clamp 90 can be mounted and dismounted as required.

A rigid lug, base or support 92 is suitably supported on any accessible portion of the frame of the device. In the embodiment illustrated, the lug 92 has been made integral with and extending from cover 33. A medial portion 93 of an elongated traction wheel release lever or arm 94 is superposed with respect to the lug 92. A

6 compression spring 95 at one end bears against the medial portion 93 of said lever 94.

On its outer end portion, lever 94 has a handle 96 by which said arm or lever 94 can be gripped. At its inner end portion, the lever or arm 94 is preferably enlarged to provide an elongated head 97, the longitudinal axis of which extends transversely of the longitudinal axis of the lever or arm 94, as illustrated in FIG. 2. By means of fasteners 98, such as bolts or the like, which extend through the opposite end portions of the head 97, the lever 94 is tied to, and connects together, the hearing or rotor flange '78 and the rotor 71. As illustrated in FIG. 3, head 97 is eccentrically disposed.

When the reversible motor 11 is in the feed portion of its cycle, the driving force is transmitted through the spiroid input pinion 12 to the spiroid gear head 14 which is carried by said pinion. The spiroid gear head 14, by reason of its mesh with the external worm or spiroid gear 44, causes the gear 44 to rotate counterclockwise in the bore 41 as seen in FIGS. 1, 2 and 4.

The counterclockwise torque of the gear 44 is transmitted to planet gear 55 by reason of the meshing of the

teeth

53 and 54; and accordingly gear 55 is set in counterclockwise rotation about its axis of rotation. Additionally, the torque of the gear 44- tends to revolve gear 55 about the axis of rotation of the gear 44.

The torque tending to revolve the spur planet gear 55 about the axis of gear 44 is transmitted to the rotor 71 and its flange in which the shaft 56 of said gear 55 is mounted. Thereby, rotor 71 and flange 73 tend to rotate counterclockwise with respect to FIGS. 1, 2 and 4.

The counterclockwise torque of the rotor 71 will cause traction wheel 57 to be revolved about the axis of gear 44 which is the same as the axis of rotation of rotor 71. Such motion carries traction wheel 57 away from back up wheel 69. However, the counterclockwise torque of rotor 71 is translated into a counterclockwise rotation of the lever 94 toward lug 92 to compress the spring 95. The counterclockwise rotation of the arm 94 is limited by the reaction of spring 95 tending to rotate the lever 94 clockwise.

By predetermination in a manner well known in the art, spring 95 can be selected which will restrain rotation of the lever 94 at a point prior to the separation of the teeth 68 from the strapping S so that during the feeding portion of the cycle, strapping S is positively driven by teeth 68, when rotating in a counterclockwise direction with respect to FIGS. 1, 2 and 4. With the feeding torque thus balanced by the force resisting compression of the spring 95, rotor 71 is thus held in a substantially fixed position. Accordingly, the spur planet gear 55 will be unable to revolve about the axis of rotation of the spiroid gear 44 and rotor 71, and therefore said planet gear will merely rotate idly about its axis of rotation.

Having described the manned in which the traction wheel 57 will tend to move away from back up roller 69, it is appreciated that when strap S is for the first time threaded through the device, or when it must be replaced or positioned for operation, sufficient manual force applied to the handle 96 will compress the spring 95 sufliciently to permit rotation of rotor 71 counterclockwise a distance great enough to separate the toothed traction wheel 57 and the back up wheel 69. Thereupon, strap S may be passed easily between the

opposed wheels

57 and 69.

Once the feeding of the strap S has been completed and the motor has been reversed, removal of the slack from and tensioning of the strap S ensues prior to sealing and segmentation thereof. With reference to FIG. 1, strap S moves downwardly during tensioning; and the tensioning torque is clockwise with respects to FIGS. 1, 2 and 4. As the tensioning operation proceeds, the force required to tension the strap S increases by reason of the increasing resistance to tensioning which is built up in the strap. Such increasing demand for force is supplied in accordance with the heretofore described construction by means comprising the spiroid gear 44 which is caused to rotate clockwise with respect to FIGS. 1, 2 and 4, by prime mover 11. Such clockwise rotation causes spur planet gear to also rotate clockwise about its axis of rotation. However, in addition the spur planet gear 55 tends to revolve clockwise about the axis of rotation of the gear 44. This torque complemented partially by the normal expansion of the spring 95 tends to rotate the rotor 71 clockwise as well as the arm 94 to which said rotor is secured.

Inasmuch as the axis of rotation for the arm 94 and the rotor or eccentric 71 is the axis of rotation for gear 44, the shaft 56 carried in the eccentric opening 72 will be revolved about the axis of gear 44 and moved toward the fixed shaft 70 of the back up wheel 69. Such movement of the shaft 56 carries with it the traction wheel 57 which accordingly will move toward the back up wheel 69 and thereby cause progressive embedding of the teeth 68 in and increasing gripping and tensioning force applied on the strap S.

Referring now to the modified form of the strap feeding and tensioning mechanism seen in the drawings in FIGS. and 6, the traction wheel 157 is secured on shaft section 156 which is part of the shaft 112 and which provides an axis for rotation for said traction wheel 157. To effectuate the mounting of the traction wheel 157, a plurality of grooves 155 are provided in the outer end portion 154 of the shaft 156. The grooves 155 extend longitudinally of said shaft 156 and have mounted therein longitudinal splines 153 of a spline means 152. Fasteners such as socket or countersunk screws 15-1 rigidly secure the spline means 152 to the outer end portion 154 of the shaft 156.

At their inner end portions the spline means 152 have enlarged integral keys 158 which extend outwardly from the slot or grooves 155. The traction wheel 157 has a plurality of inner keyways 159 in which keys 158 are disposed to lock the traction wheel 157 on the shaft 156 from independent rotation with respect to said shaft.

The traction wheel 157 is restrained from displacement longitudinally of the shaft 156 by means of a pair of annular spacers 148 and 149 which are disposed about shaft end portion 154 in spaced relationship longitudinally of the shaft 156. The inner face of the spacer 148 bears against the outer flat 147 of the traction wheel 157. The outer face of the spacer 148 bears against an annular race of bearing 146. The outer face of the inner spacer 149 bears against the inner flat 145 of traction wheel 157. The inner face of the spacer 149 bears against the annular race of bearing 150.

The shaft 156 is journalled in the bearing members 146 and 150, in the manner illustrated in the drawings. The means providing for retention of the bearings 146 and 150 will be hereinafter described.

The shaft 156 is operably connected to and has the same axis of rotation as drive shaft 112 which is rotatably driven by the prime mover. In the modified embodiment being described the prime mover is a reversible air motor characterized by a housing 111 which tends and is free to rotate in a direction opposite the normal torque of the shaft 112 in proportion to the resistance to rotation of said shaft. Accordingly therefore, when the shaft 156, which rotates clockwise with respect to FIG. 5 during the strap tensioning operation, tends to stall because of insufiicient torque, the housing 111 will be caused to rotate counterclockwise.

Housing 111 has an annular flange 1 1 3 which is centrally apertured to accommodate the drive shaft 112. The flange 113 is rigidly connected by means of fasteners such as bolts or the like 114 to the radially extending flange 115 of a motor mount or bushing generally designated by the numeral 116.

The motor mount or bushing 116 has an integral annular outwardly extending journalling extension, eccentric portion or rotor 171 which has an eccentric passage or bore 172 common with the central bore of the flange 115. Thereby flange is concentric with said bore 172, and the rotor or eccentric journalling extension 171 is disposed eccentrically with respect to flange 115 and said bore 172, as illustrated in the drawings in FIGS. 5 and 6. Accordingly, the shaft 156 is centrally disposed with respect to the flange 115, but it is eccentrically disposed with respect to the rotor or eccentric 171.

Bore 172 is enlarged to provide an annular shoulder 173 against which outer peripheral portion of the central race of the ball bearing 1'50 abuts. A retaining ring 175 seated in groove 176 formed in the central surface of flange 115 bears against the opposite face of the peripheral race of the bearing 150 to complete the retention of said bearing.

The frame 110 to accommodate the modification illustrated in FIGS. 5 and 6, is provided with a passage or bore 118 which is circular in cross section and which extends longitudinally of the shaft 156. A pair of annular bushing or bearing

liners

117 and 119, fabricated from any suitable bearing material such as bronze and the like, are suitably mounted in the bore 118 in spaced apart relationship longitudinally of rotor 17 1.

Bushing 117 has an inner radial flange 120 which extends outwardly from the bore 118 between a portion of the frame 110 and the forward face of the radial flange 115 to provide a bearing between said flange 115 and the frame 110, as illustrated in FIG. 6. Bushing 119 has an integral outer radial flange 121 which extends outwardly from bore 118 and provides a bearing between the frame 110 and a motor mount flange or ring 122. The medial or axially extending portion 127 of the

annular bushings

117 and 119 provide the bearing for rotation of the rotor or eccentric 171 within the frame aperture 118, as illustrated in the drawings.

The motor mount flange 122 is disposed in a well 123 which comprises an outer end extension of the bore 118 having an enlarged diameter to accommodate said ring 122. The width of the motor mount flange 122 permits an inner annular portion 124 thereof to cover the outer end face of an outer peripheral portion 125 of the rotor 1711 to which said ring is secured by means of a plurality of fasteners such as screws or the like 126, as illustrated in the drawings.

Accordingly, it is seen that the flange 115 retains the assembly from outward movement or displacement, and the flange or ring 122 retains the assembly from inward movement or displacement.

A bearing cap generally designated as 128 is mounted centrally of the motor mount flange 122. Said cap 128 covers the outer end of the opening 172 and has a radial flange 129 which is disposed against the outer face of the centerward portion 130 of the rotor 171. By means of fasteners such as screws or the like 177, and a grease fitting 131, two of which are seen in FIG. 5, the bearing cap 128 is secured to said rotor 171.

Bearing cap 128 has an inwardly extending elongated axial eccentric flange 132, the outer diameter of which is substantially the same as the inner diameter of the rotor 171 or of the bore 172. Flange 132 is disposed against the inner face of rotor 171 whereby the radius of said bore 172 is reduced by the thickness of the radial flange 132, as illustrated in FIG. 6. Within said bore 172 the flange 132 is disposed about an outer end portion 154 of the shaft 156.

A retaining ring 133 mounted in an annular groove provided therefore in the inner surface of the wall of the flange 132 bears against the peripheral portion of the race of bearing 146, as illustrated in FIG. 6. Said retaining ring 133 together with the spacer 148 preclude inward movement of the bearing 146. Outward movement or displacement of the bearing 146 is precluded by the abutment of the outer surface of the peripheral race of bear- 9 ing 146 with the shoulder 134 generated in the inner surface of the flange 132, as illustrated in FIG. 6.

A traction wheel release lever or arm 194 having at the outer end portion thereof a hand grip 196 has its inner end portion 193 suitably secured such as welding 174 or the like to a flat plate or lever anchoring member 197, as illustrated in the drawings. The inner flat of plate 197 is disposed against the outer surface of bearing cap 128 to which it is secured by means of fasteners such as screws 177. Screws 177 also tie plate 197 to rotor 171 and bearing cap 128 to rotor 171.

Back up wheel or pressure roller 169 is rotatable about a fixed axis provided by a shaft 170 to which said back up wheel or pressure roller 169 is rigidly secured or fixed.

As illustrated in FIG. 5, a peripheral portion of the flange 115 is cut away to provide a shoulder flat 190 from which there extends a dowel or pin 191. A pin or bolt 192 is rigidly secured in the frame 110 in axial alignment with the dowel 191. The bolt 192 carries a collar 193 adapted to be adjusted longitudinally of the bolt 192 in any suitable fashion, as for example by an adjusting nut 195. A compression spring 198 is mounted about the bolt 192 and the pin 191 with one end of said spring bearing against the end face 199 of said bolt 193 and the other end of said spring bearing against the shoulder 190 in position disposed about said pin 191. When the spring 198 is under compression it exerts its force against flange 115 and thereby tends to rotate the motor mount 116 counterclockwise about the center of rotation of rotor 171.

By pushing the handle 196 downwardly, that is rotating it clockwise about its connection with plate 197, rotor 171 will rotate clockwise. Traction wheel 157 will be revolved about the center of rotation of the rotor 171 and thereby be carried slightly away from the back up wheel or pressure roller 169 and permit the initial positioning of the strap SS between said traction wheel 157 and back up wheel 169. Such initial rotation will compress the spring 198. Upon release of the handle the spring 198 will decompress and will rotate rotor 171 counterclockwise and carry the traction wheel 157 back to its normal starting position with respect to the back up wheel 169.

The strap SS will then be fed until a desired length thereof is in position around the article to be tied and during such feeding the traction wheel 157 will rotate counterclockwise with respect to FIG. 5.

Because of its load the spring 198 will not have any effect on the position of the motor mount 116 except to the extent that it will overcome any tendency of housing 111 and accordingly motor mount 116, to rotate clockwise during the feeding operation. However, as there is no substantial resistance to the rotation of the traction wheel 157 during the feeding operation, the input energy to the prime mover will be translated into counterclockwise rotation of the shaft 112, and therefor the shaft 156, to drive the traction wheel 157. Under such conditions there will be virtually no movement of the motor mount 116.

After the desired amount of strap SS has been fed, the drive of the prime mover will be reversed in a manner heretofore described for reversal of the drive. Thereupon, the tensioning operation commences and accordingly, the traction wheel 157 will be driven clockwise with respect to FIG. 5, with a resultant strap movement to the right.

As the tensioning increases, the resistance thereto in the strap SS increases, with the resultant requirement of more torque in the traction wheel 157 to move the strap SS in the tensioning direction. As the resistance to the tensioning increases, the shaft 156 and the traction wheel 157 carried thereby will slow down and tend to stall with a corresponding action set up in the motor shaft 112 with a resultant build up of torque.

A reaction occurs in housing 111 with the input energy for the prime mover translated into a torque tending to 10 rotate motor housing 111 counterclockwise with respect to FIG. 5. The degree of the reaction is proportional to the slowing down of the rotation and increase in torque on the shaft 156 caused by the drag resulting from the resistance to the tensioning.

As the motor housing 111 rotates, it carries with it the mot-or mount 116 and the integral eccentrically bored rotor or eccentric 171 in which the shaft 156 is journalled. Rotation of the motor mount is about an axis defining the center of the rotor or eccentric 171 and extending longitudinally thereof. With respect to FIG. 5 therefore, it is appreciated that the counterclockwise rotation of the rotor 171 will rock traction wheel 157 counterclockwise about the axis of rotation of rotor 171 to carry traction wheel 157 into closer engagement with or toward back up wheel or roller 169 to more forcefully grip the tensioned strap and exert a greater tensioning force thereupon. Accordingly, as the shaft 156 again beg-ins to rotate clockwise, as it overcomes the resistance in the tensioned strap SS, the tendency of the eccentric 171 to rotate or rock counterclockwise will diminish in proportion to the overcoming of the resistance in the strap SS.

From the foregoing it is appreciated that the herein described tensioning mechanisms are capable of self energization in accordance with the torque requirements to tension the strap undergoing tensioning and in which the resistance to such tensioning is gradually increasing. Furthermore, because of the mechanical advantage inherent in the described construction, rapid building of torque applied to the tensioned strap is insured. Inasmuch as the mechanical advantage is determined by the moment between the axis of rotation of the rotor and the axis of rotation of the traction wheel as well as the radius of the traction wheel, variation thereof may be had from one device to another.

As many substitutions or changes could be made in the above described construction, and as many apparently widely different embodiments of the invention within the scope of the claims could be constructed without departing from the scope and spirit thereof, it is intended that all matter contained in the accompanying specification shall be interpreted as being illustrative and not in a limiting sense.

I claim:

1. In a strapping machine for binding bundles and the like with a band of tensioned strap, the combination of means providing a frame, prime mover means, means for guiding strap through said frame, reversible means for feeding strap through said guiding means and applying tension to and shrinking such strap about a bundle, said reversible means including a back up wheel rotatable on an axis of reaction and a traction wheel and rotatable shaft therefor between and by which strap is fed and tensioned in opposite directions, and a driven eccentric movably connected to said prime mover means and rotatably mounting said shaft to rotate about a floating axis and shift the traction wheel towards and away from said back up wheel in accordance with the loading imposed on the prime moving means in advancing the strap.

2. In a strapping machine for binding bundles and the like with a band of tensioned strap and including prime mover means, and traction means for applying tension to and shrinking the strap about a bundle, said traction means including a back up wheel and a traction wheel and shaft therefor between and by which the strap is advanced, the subcombination of means for controlling force application on the strap by said traction means comprising a rotatable rotor housing rotatably connected to said prime mover means, a rotor journalled within said rotor housing, said shaft disposed eccentrically in said rotor, and force transmission means for transmitting the rotational force of said rotor housing to said rotor in a loading direction to shift said shaft for moving the traction wheel closer to the back up wheel as tension on the strap is increased.

3. In a strapping machine in accordance with claim 2 and spring means yieldingly resisting rotation of the rotor in the loading direction.

4. In a strapping machine for binding bundles and the like with a band of tensioned strap, the combination of means providing a frame, prime mover means, means for guiding binding strap through said frame, reversible means for feeding strap through said guiding means and applying tensioning to and shrinking such strap about a bundle, said reversible means including a back up wheel rotatable on a first fixed axis and a traction wheel and rotatable shaft therefor between and by which binding strap is fed and tensioned in opposite directions, with a driven rotor rotatably connected to said prime mover means, said rotor having an opening disposed eccentrically from its axis of rotation, said shaft journalled in said opening; and means for intermittently driving said rotor whereby the gripping force of said back up wheel and traction wheel is varied during tensioning.

5. In a strapping machine for binding bundles and the like with a band of tensioned strap, the combination of means providing a frame, prime mover means, means for guiding strap through said frame, reversible means for feeding strap through said guiding means and applying tensioning to and shrinking such strap about a bundle, said reversible means including a backup wheel rotatable on an axis of reaction and a traction wheel and rotatable shaft therefor between and by which binding strap is fed and tensioned in opposite directions, with a driven rotor rotatably connected to said prime mover means, said rotor having an opening disposed eccentrically from its axis of rotation, said shaft journalled in said eccentric opening whereby spacing of said back up wheel and traction wheel is varied, and means limiting the rotation of said rotor.

6. In a strapping machine for binding bundles and the like with a band of tensioned strap, the combination of means providing a frame, a prime mover, means for guiding strap through said frame, and reversible means for feeding strap through said guiding means and applying tension to and shrinking such strapping about a bundle, said reversible means including a back up wheel rotatable on a fixed axis and a traction wheel and shaft therefor between and by which strap is fed and tensioned in opposite directions, with rotor housing in said frame, a rotor mounted in said housing about a fixed axis of rotation, said shaft eccentrically journalled in said housing; means connected to said prime mover for rotating said rotor and means connected to said prime mover for driving said shaft whereby the traction wheel rotates in positions adjustably spaced from said back up wheel.

7. In a strapping machine for binding bundles and the like with a band of tensioned strap, having means providing a frame, prime mover means, means for guiding strap through said frame, and reversible means for feeding strapping through said guiding means and applying tension to and shrinking such strap about a bundle, said reversible means including a back up Wheel rotatable on a fixed axis and a traction wheel and shaft therefor between and by which strap is fed and tensioned in opposite directions, the subcombination of means for controlling force applied on strap by said reversible means comprising a driven internal gear member rotatably connected to said prime mover means; a planet gear driven by and rotating on an axis eccentric to said internal gear member, said planet gear secured to said shaft, whereby the traction wheel is moved to and away from said back up wheel.

8. In a strapping machine for binding bundles and the like with a band of tensioned strap, having means providing a frame, prime mover means, means for guiding strap through said frame, and reversible means for feeding strap through said guiding means and applying tension to and shrinking such strapping about a bundle, said reversible means including a back up wheel rotatable on a fixed axis and a traction wheel and shaft therefor between and by which strap is fed and tensioned in opposite directions, the subcombination of means for controlling force applied on strap by said reversible means comprising a driven gear ring rotatably connected to said prime mover means and disposed about said shaft; a planet gear driven by and disposed eccentrically with said gear ring, said planet gear secured to said shaft; a pivoted lever operably connected to said shaft, and means for pivoting said lever partially to revolve said shaft about the axis of rotation of said gear ring whereby the gripping force of said back up wheel and traction wheel is adjusted.

9. In a strapping machine for binding bundles and the like with a band of tensioned strap, having means providing a frame, prime mover means, means for guiding strap through said frame, and reversible means for feeding strap through said guiding means and applying tension to and shrinking such strap about a bundle, said reversible means including a back up wheel rotatable on a fixed axis and a traction wheel and shaft therefor between and by which strap is fed and tensioned in opposite directions, the subcombination of means for controlling force applied on strap by said reversible means comprising a driven ring gear rotatably connected to said prime mover means and disposed about said shaft; a planet gear eccentrically disposed within and driven by said ring gear, said planet gear secured to said shaft; a pivoted lever operably connected to said shaft; means for driving said shaft partially about the axis of rotation of said ring gear and a spring bearing against a portion of said lever whereby separation of said back up wheel and traction wheel is limited during strap feeding.

10. In a strapping machine for binding bundles and the like with a band of tensioned strap, having means providing a frame, prime mover means, means for guiding strap through said frame, and reversible means for feeding strap through said guiding means and applying tension to and shrinking such strap about a bundle, said reversible means including a back up wheel rotatable on a fixed axis and a traction wheel and shaft therefor between and by which strap is fed and tensioned in opposite directions, the subcombination of means for controlling force applied on strap by said reversible means comprising a driven ring gear rotatably connected to said prime mover means and disposed about said shaft; a planet gear driven by and eccentrically disposed within said ring gear, said planet gear secured to said shaft; a driven rotor, said shaft eccentrically journalled in said rotor; a lever operable connected to said rotor, and a spring bearing about an outer portion of said lever whereby as said shaft rotates in one direction said spring holds said lever and rotor from pivoting and as said shaft rotates in an opposite direction said lever is pivoted and causes said rotor to rotate.

11. In a strapping machine for binding bundles and the like with a band of tensioned strap, having means providing a frame, prime mover means, means for guiding strap through said frame, and reversible means for feeding strapping through said guiding means and applying tension to and shrinking such strap about a bundle, said reversible means including a back up wheel rotatable on an axis of reaction and a traction wheel and shaft therefor between and by which strapping is fed and tensioned in opposite directions, the subcombination of means for controlling force applied on strap by said reversible means comprising a rotatable rotor housing rotatably connected to said prime mover means, a rotor journalled within said rotor housing, said shaft disposed eccentrically in said rotor, and force transmission means for transmitting the rotational force of said rotor housing to said rotor, whereby said traction wheel is moved toward and away from said back up wheel.

12. In a strapping machine for binding bundles and the like with a band of tensioned strap, having means providing a frame, prime mover means, means for guiding strap through said frame, and reversible means for feeding strap through said guiding means and applying tension to and shrinking such strap about a bundle, said reversible means including a back up wheel rotatable on a fixed axis and a traction wheel and shaft therefor between and by which strap is fed and tensioned in opposite directions, the subcornbination of means for controlling force applied on strapping by said reversible means comprising a rotatable rotor housing rotatably connected to said prime mover means, a rotor journalled in said housing and having an eccentric opening, said shaft journalled in said opening; a force transmission link operably connected to said shaft and driven by said rotor housing, and a spring biased lever connected to said rotor and thereby controlling the relative disposition of said rotor within said housing and the traction wheel secured to said shaft.

13. In a strapping machine for binding bundles and the like with a band of tensioned strap, having means providing a frame, means for guiding strap through said frame, and reversible means for feeding strap through said guiding means and applying tension to and shrinking such strap about a bundle, said reversible means including a back up wheel rotatable on a fixed axis and a traction wheel and shaft therefor between and by which strap is fed and tensioned in opposite directions, the subcombination of means for controlling force applied on strap by said reversible means comprising a rotor rotatable about a fixed axis in said frame and disposed about said shaft; a motor, the stator of said motor operably connected to said rotor, said motor operably connected to said shaft, whereby as said shaft tends to stop, said rotor tends to rotate and thereby move the traction wheel to and away from said back up wheel.

14. In a strapping machine for binding bundles and the like with a band of tensioned strap, having means providing a frame, means for guiding strap through said frame, and reversible means for feeding strap through said guiding means and applying tension to and shrinking such strap about a bundle, said reversible means including a back up wheel rotatable on a fixed axis and a traction wheel and shaft therefor between and by which strap is fed and tensioned in opposite directions, the subcombination of means for controlling force applied on strap by said reversible means comprising a rotor rotatable about a fixed axis in said frame, said rotor having an eccentric opening; said shaft disposed in said opening; a motor and rotatable housing therefor, said motor connected to said shaft, said housing connected to said rotor, whereby on slowing of said shaft said housing tends to rotate the rotor and move said shaft about the axis of rotation of said rotor.

15. In a strapping machine for binding bundles and the like with a band of tensioned strap, having means providing a frame, means for guiding strap through said frame, and reversible means for feeding strap through said guiding means and applying tension to and shrinking such strap about a bundle, said reversible means including a back up wheel rotatable on a fixed axis and a traction wheel and shaft therefor between and by which strap is fed and tensioned in opposite directions, the subcombination of means for controlling force applied on strap by said reversible means comprising a rotor rotatable about a fixed axis in said frame, said rotor having an eccentric bore, said shaft journalled in said bore; a motor operably connected to said shaft; a motor housing rotatable reciprocally to, and about the axis of rotation of, the motor and connected to said rotor; and spring biased means operably connected to said rotor,

14 whereby the traction wheel is urged toward said back up wheel.

16. In a strapping machine for binding bundles and the like with a band of tensioned strap, having means providing a frame, means for guiding strap through said frame, and reversible means for feeding strap through said guiding means and applying tension to and shrinking such strap about a bundle, said reversible means including a back up wheel rotatable on a fixed axis and a traction wheel and shaft therefor between and by which strap is fed and tensioned in opposite directions, the subcombination of means for controlling force applied on strap by said reversible means comprising a driven rotor journalled about a fixed axis in said frame, said rotor having an eccentric bore; a motor operably connected to said shaft, said shaft journalled in said eccentric bore; a motor housing secured to said rotor and adapted for rotation reciprocally to the rotation of said motor whereby as said traction wheel tends to stall during tensioning, said motor housing tends to rotate said rotor to revolve said shaft about the axis of rotation of said rotor and change the position of the traction wheel.

17. In a strapping machine for binding bundles and the like with a band of tensioned strap, having means providing a frame, means for guiding strap through said frame, and reversible means for feeding strap through said guiding means and applying tension to and shrinking such strap about a bundle, said reversible means including a back up wheel rotatable on a fixed axis and a traction wheel and shaft therefor between and by which strap is fed and tensioned in opposite directions, the subcombination of means for controlling force applied on strap by said reversible means comprising a rotor journalled about a fixed axis in said frame, said shaft journalled in said rotor about an axis eccentric to the axis of rotation of said rotor, and a prime mover having reciprocally rotatable components operably connected to said rotor and said shaft, respectively, and adapted to drive said shaft and said rotor in opposite directions, whereby as said shaft slows and torque is increased during tensioning the traction wheel is raised toward said back up wheel.

18. In a strapping machine for binding bundles and the like with a band of tensioned strap, the combination of means providing a frame, prime mover means, means for guiding binding strap through said frame, reversible means for feeding strap through said guiding means and applying tensioning to and shrinking such strap about a bundle, said reversible means including a back up wheel rotatable on an axis of reaction and a traction wheel and rotatable shaft therefor between and by which binding strap is fed and tensioned in opposite directions, with a driven rotor rotatably connected to said prime mover means, said shaft journalled in said rotor; means for partially rocking the shaft about the axis of rotation of said rotor whereby the spacing of said back up Wheel and traction wheel can be varied and means for limiting the rotation of said rotor.

References Cited by the Examiner UNITED STATES PATENTS 2,215,121 9/1940 Harvey et al. l0026 X 2,438,386 3/1948 Chamberlain -29 X 2,915,003 12/1959 Crosby et al. l0026 2,915,004 12/1959 Leslie 100-26 3,023,693 3/1963 Crosby et al. 10032 3,086,451 4/1963 Van der Wal 10026 3,088,397 5/1963 Martin et al. 10026 WALTER A. SCHEEL, Primary Examiner.

BILLY J. WILHITE, Examiner.

Claims

1. IN A STRAPPING MACHINE FOR BINDING BUNDLES AND THE LIKE WITH A BAND OF TENSIONED STRAP, THE COMBINATION OF MEANS PROVIDING A FRAME, PRIME MOVER MEANS, MEANS FOR GUIDING STRAP THROUGH SAID FRAME, REVERSIBLE MEANS FOR FEEDING STRAP THROUGH SAID GUIDING MEANS AND APPLYING TENSION TO AND SHRINKING SUCH STRAP ABOUT A BUNDLE, SAID REVERSIBLE MEANS INCLUDING A BACK UP WHEEL ROTATABLE ON AN AXIS OF REACTION AND A TRACTION WHEEL AND ROTATABLE SHAFT THEREOF BETWEEN AND BY WHICH STRAP IS FED AND TENSIONED IN OPPOSITE DIRECTIONS, AND A DRIVEN ECCENTRIC MOVABLY CONNECTED TO SAID PRIME MOVER MEANS AND ROTATABLY MOUNTING SAID SHAFT TO ROTATE ABOUT A FLOATING AXIS AND SHIFT THE TRACTION WHEEL TOWARDS AND AWAY FROM SAID BACK UP WHEEL IN ACCORDANCE WITH THE LOAD-