US3794086A

US3794086A - Apparatus for forming a seal-less type joint in overlapped flat strapping

Info

Publication number: US3794086A
Application number: US00284841A
Authority: US
Inventors: M Hall; C Krack
Original assignee: United States Steel Corp
Current assignee: STANWICH HOLDINGS Inc A DE CORP; L&P Property Management Co; Signode Corp
Priority date: 1972-08-30
Filing date: 1972-08-30
Publication date: 1974-02-26
Anticipated expiration: 1991-02-26

Abstract

Apparatus includes a pair of opposed jaws mounted at one end for pivotal movement toward and away from each other. Mating notches are provided on the opposing faces of the jaws remote from their pivoted ends for forming a fixed die for receiving overlapped flat strapping. A punch is disposed for reciprocal movement between the opposed edges of the jaws toward and away from the fixed die formed by the notched portions of the jaws. The punch is shaped so as to form interconnecting tabs in the overlapped portion of the flat strapping resting on the fixed die. A cutter is mounted on the punch for movement therewith which serves to cut the length of strapping proximate to the source of flat strapping. A linkage system is provided connected with each jaw which is actuatable by the punch as it travels away from the fixed die to open the jaws to release the overlapped portions of the strapping after the punch has joined them together and the cutter has cut the strapping from its source. Spring means are provided connected with the linkage system to constantly urge the jaws toward each other. The apparatus also includes a micrometer adjusting means to adjust the clearance between the jaws.

Description

United States Patent [191 Hall et al. 1 Q

Mans [45] Feb. 26, 197

[ APPARATUS FOR FORMING A SEAL-LESS TYPE JOINT IN OVERLAPPED FLAT STRAPPING [75 Inventors: Marchand E. Hall, Olympia Fields;

Carl E. Krack, Evergreen Park, both of 111.

[73] Assignee: United States Steel Corporation, Pittsburgh, Pa.

[22] Filed: Aug. 30, 1972 [21] Appl. No.: 284,841

Primary Examiner-Lowell A. Larson Attorney, Agent, or FirmDonald S. Ferito [57] ABSTRACT Apparatus includes a pair of opposed jaws mounted at one end for pivotal movement toward and away from each other. Mating notches are provided on the opposing faces of the jaws remote from their pivoted ends for forming a fixed die for receiving overlapped flat strapping. A punch is disposed for reciprocal movement between the opposed edges of the jaws toward and away from the fixed die formed by the notched portions of the jaws. The punch is shaped so as to form interconnecting tabs in the overlapped portion of the flat strapping resting on the fixed die. A cutter is mounted on the punch for movement therewith which serves to cut the length of strapping proximate to the source of flat strapping. A linkage system is provided connected with each jaw which is actuatable by the punch as it travels away from the fixed die to open the jaws to release the overlapped portions of the strapping after the punch has joined them together and the cutter has cut the strapping from its sourcev Spring means are provided connected with the linkage system to constantly urge the jaws toward each other. The apparatus also includes a micrometer adjusting means to adjust the clearance between the jaws.

4 Claims, 13 Drawing Figures PATENTEB FEB26 I974 Wm mm S MEI h um I. -91

Nb QM T o v x? J mm h w PL am 3 wk E APPARATUS FOR FGMING A SEAL-LESS TYPE JOINT IN OVERLAIIPED FLAT STRAPIING The present invention relates generally to strapping equipment and more particularly to apparatus for forming a se al-less type of joint in overlapped flat strapping, the apparatus being especially suitable for use with automatic strapping machines.

The apparatus of the invention forms a seal-less joint in the overlapped portion of flat strapping that has been tensioned around an article, such as a bundle or pack age, by die-cut notching the overlapped strapping. Prior to our invention tools for so interlocking the overlapped strapping included a punch and die portion and generally some difficulty was encountered in extracting the joined strapping from the tool because either the punch or the die portion lay under the strapping and in a hand tool the joint strapping had to be extracted manually. In the case of an automatic strapping machine, elaborate extraneous accessories had to be provided to achieve extraction of the joined strapping. This, of course, added to the initial cost of the machine and the cost of maintenance thereafter. The present invention contemplates an arrangement wherein the die is a twopiece split die that separates after a joint has been formed in the strapping, leaving no elements beneath the joined strapping and thus avoids any problem of ejecting the joined strapping from the tool or extracting any part of the tool from under the strapping.

It is, accordingly, the primary object of our invention to provide an improved apparatus for forming a sealless type joint in overlapped flat strapping which apparatus includes a punch; a two-piece split die; a linkage system connected with the split die whereby the two parts of the die are separated to release a joined overlapped strapping by interaction of the linkage and the punch moving away from the split die after the joint has been formed; spring means connected with the linkage system to constantly urge it into a position whereby the two parts of the die are urged to close position to form a fixed die; and a micrometer adjusting means to adjust the clearance between the two parts of the die.

This and other objects will become more apparent after referring to the following specification and attached drawing, in which:

FIG. I is an elevational view partly in section of the apparatus of the invention with parts broken away for clarity showing the components of the apparatus in position preparatory to the start of a sealing cycle;

FIG. 2 is an elevational view partly in section taken substantially along the line IllI of FIG. 11;

FIG. 3 is a partial elevational view of the lower portion of the frame plate of the invention shown substantially cut away in FIG. 1;

FIG. 4 is a cross sectional view taken substantially along the line IV-IV of FIG. 3;

FIG. 5. is a vertical sectional view taken substantially along the line V-V of FIG. I and showing the apparatus of the invention in operative position relative to a strapping wrapped around a package;

FIG. 6 is a view substantially similar to FIG. I with the one frame plate substantially removed showing the apparatus of the invention in its second stage of operation just prior to forming the seal-less joint;

FIG. 7 is a view substantially similar to FIG. 6 showing the apparatus in its third stage of operation where the components of the apparatus of the invention are in position forming the seal-less joint in the overlapped strapping;

FIG. 8 is substantially similar to FIG. 7 but showing the apparatus in its fourth stage of operation, with the cutter blade removed, wherein the punch is moving away from the formed seal-less joint;

FIG. 9 is a view substantially similar to FIG. 8 showing the apparatus of the invention in its final stage of operation, with the cutter blade removed, wherein the punch is fully retracted and the jaws of the apparatus are pivoted away from each other to release the formed seal-less joint;

FIG. III is a horizontal cross sectional view taken substantially along the line )(X of FIG. 6;

FIG. II is a partial elevational view taken substantially along the line XI-XI of FIG. III;

FIG. I2 is a view in perspective of the seal-less type joint formed by the apparatus of the invention; and

FIG. I3 is a longitudinal sectional view taken substantially along the line Xlll-XIII of FIG. 12.

Referring now more particularly to the drawing, reference numeral 2 designates generally the jointforming apparatus of the invention which includes a pair of

frame plates

4 and 6 joined together in rigid spaced relationship. A hydraulic cylinder 30 is fixedly mounted on the frame plates, as best shown in FIG. 1, by means of a plate 8 integral with the cylinder and screws 10. Each of the

plates

4 and 6 is formed with a longitudinal slot I2 on its inner face which matches with a mating longitudinal slot 12 formed on the inner face of the opposite plate for a purpose which will become apparent.

A pair of elongated jaw members 14 are pivotally mounted at their upper ends between the

frame plates

4 and 6 by means of shafts I6 which are secured in position by nuts 18. The portion of the opposite faces of the jaws M below the pivot shaft 16 are undercut as at 20. A punch 22 is mounted for reciprocal vertical movement, as best shown in FIGS. ll, 6, 7, 8, and 9, between the jaws ll4 toward and away from the free ends of the jaws. The mating slots I2 provide a containment and passageway for the punch 22. The upper end of the punch 22 is connected with a clevis 24 by means of a pin 26 which clevis, in turn, is attached to the piston rod 28 of the hydraulic cylinder 36..

The opposing lower edges 32 of the jaws 14 are notched to form a fixed die when the opposed longitudinal edges of the jaws 14 are parallel. The bottom 23 of the punch 22 is shaped to cooperate with the die formed by the notches 32 to punch interlocking tabs 34 in an overlapped strapping portion L, resting in the notches 32, of a strapping S tensioned around a package P.

The lower edges of the

frame plates

4 and 6 are formed with substantially

U-shape notches

36 and 38, respectively. As best shown in FIGS. 3 and 4, a short plate or block 46 is rigidly disposed in the notch 36 of the plate 4 by means of cap screws 42. The plate 40 is formed with a passage ring 44 on the top thereof for receiving the upper strand of the overlapped portion L of the strapping S while the lower strand of the strapping S in the overlapped portion L travels below the plate 40, as best shown in FIG. 4.

The punch is formed with bearing surfaces 46 adjacent its lower end, the purpose of which will become apparent hereinafter. A protrusion 48 is formed on the punch 22 intermediate its ends for carrying a cutter blade 50, as best shown in FIGS. 1, 4, S, 6,- and 7. The cutter blade 50 travels with the punch 22 and serves to cooperate with the plate 40, which functions as a fixed cutter blade, to cut the upper strand of the strapping S in the overlapped portion L from the source (not shown) of the strapping after the seal-less joint in the overlapped portions of the strapping has been formed, as best shown in FIGS. 4 and 5.

Each of the jaws 14 is formed with a substantially ovular opening 52 having its major axis extending longitudinally of its respective jaw. A bearing 54 having axially extending stub shafts 56 projecting from opposite sides thereof is disposed in each of the openings 52 for linear movement along the walls of the openings for a purpose which will become apparent.

Two pairs of

elongated links

58 and 60 are rotatably mounted on

shafts

62 and 64, respectively, which extend through the

frame plates

4 and 6 adjacent opposite edges thereof. Shoulders are formed on

shafts

16, 62 and 64 which together with nuts threaded on the ends of the shafts keep the

frame plates

4 and 6 joined together in rigid spaced relationship. An eccentric peripheral portion 66 is formed on each of the

shafts

62 and 64 which are disposed in the shaft openings of the

links

58 and 60. The pairs of

links

58 and 60 extend from their respective shafts transversely of opposite sides of the jaws 14 and span the openings 52 thereof. The free ends of the

links

58 and 60 are formed with upper hook noses 58' and 60 for rotatably accommodating one end of pawls 58" and 60", respectively. A coil spring 68 is provided in the free end of each of the

links

58 and 60 with one end bearing against the free end of the

pawls

58 and 60" to urge them constantly outwardly of the links toward the pathway of the punch 22. Ledges 70 are integral with the bottom portions of the jaws 14 on the face thereof toward the frame plate 4. The ledges 70 serve to support and limit the movement of the

links

58 and 60 on one side of the jaws 14, as best shown in FIG. 1. The

links

58 and 60 disposed adjacent the opposite faces of the jaws 14, as best shown in FIG. 2, are supported by an integral ledge 74 on the bottom portions of the jaws 14.. The bearings 54 in the openings 52 are connected with the

links

58 and 60 by means of the stub shafts 56 whereby pivotal movement of the

links

58 and 60 upwardly, as viewed in FIG. 9, will cause the hearings to travel upwardly in the openings 52 to cause pivotal movement of the jaws 14 away from each other.

A connecting plate 76 is attached to and extends between the two links 58 intermediate the lengths thereof. A similar connecting plate 78 is attached to and extends between the links 60. A shaft 80 extends upwardly from the connecting plate 76 and passes through a cap 82 which is attached to the

frame plates

4 and 6 and spans the space therebetween. A helical spring 84 surrounds the shaft 80 along its length and bears at one end on the connecting plate 76 and its other end on the inner surface of the cap 82 to thereby constantly urge the links 58 downwardly toward resting position on the ledges '70 and 74. A shaft 86 similar to shaft 80 extends from the connecting plate 78 through a cap 88 which cap is attached to the

frame plates

4 and 6 and spans the space therebetween. A helical spring 90 surrounds the shaft 86 along its length bearing at one end against the connecting plate 78 and its other end against the inner surface of the cap 88 to thereby constantly urge the link 60 toward the

ledges

70 and 74. Urging the links downwardly also urges the jaws 14 together.

In operation, after strapping S has been fed around package P and tensioned with the upper strap of the overlapped portion L passing through the passage ring 44 and the lower strapping of the overlapped portion passing under the plate 40, the hydraulic cylinder 30 is actuated to project the piston rod 28 to thereby cause the punch to move downwardly between the opposed edges of the jaws 14. As the punch moves between the free ends of the pawls 58" and 60", it overcomes the tension of the springs 68 and in cooperation with the notched portions 32 of the jaws 14 punches the interlocking tabs 34 in the overlapped portions of the strapping and at the same time, as best shown in FIG. 4, the cutting blade severs the upper strapping of the overlapped strapping L against the edge of the plate 40 from the strapping source (not shown). After the overlapping portions of the strapping have been thus joined together, the hydraulic cylinder 30 is again actuated to retract the piston rod 28 to cause the punch to travel upwardly away from the formed joint. As best shown in FIGS. 8 and 9, as the punch 22 travels upwardly, its bearing surfaces 46 engage the pawls 58" and and causes the

links

58 and 60 to travel upwardly which in turn cause upward movement of the bearings 54 in the openings 52. This linkage and bearing movement causes the jaws 14 to pivot away from each other thus releasing the formed seal-less joint from the apparatus of the invention. Further upward movement of the punch 22 beyond the free ends of the pawls 58" and 60" permits the links to return to initial position under the tension of

springs

84 and 90, as best shown in FIG. 1.

In order that a precise clearance between the punch 22 and the notched portions of the jaws 14 may be established, micrometer indexing adjusting devices 92 may be provided. Each of these indexing means includes an index plate 94, one fixedly mounted on a square cross-sectional portion 96 of each of the

shafts

62 and 64 which project outwardly of the frame plate 4. The index plates 94 are provided with substantially square center openings which fit snugly on the square cross-sectional portion 96 of its respective shaft. A plurality of holes 98 is provided through each of the plates 94 spaced in a substantially circular pattern around the perimeter of the shaft the plate is mounted on. The index plates 94 abut the outer face of the frame plate 4 surrounding each

shaft

62 and 64. The frame plate 4 is provided with a plurality of holes 100 spaced around the perimeter of

shafts

62 and 64 adjacent the square cross-sectional portions thereof. The plurality of holes 100 are juxtapositioned with the plurality of holes 98 in each of the plates 94', however, the number of holes in the index plates 94 exceed the number of holes in the frame plate 4. The index plates are adjustably rotatable to rotate the shafts to turn their eccentric portions 66 in the shaft openings of the

links

58 and 60 to thereby vary the clearance between the jaws. Pins 102 are provided to maintain the index plates in adjusted position. Thus, it will be seen that turning the

shafts

62 and 64 in one direction brings the jaws closer togetherdecreasing the clearance between the jaws l4 and the punch 22; and turning the index plates 94 in the opposite direction separates the jaws 14-increasing the clearance between the jaws and the punch.

While we have shown but one embodiment of our invention, other adaptations and modifications may be made without departing from the scope of the following claims.

We claim:

1. Apparatus for forming a seal-less joint in the overlapped portion of flat strapping fed from a strapping source and tensioned around an article, the strapping of said overlapped portion remote from said article being proximate to said strapping source, and apparatus comprising a pair of spaced elongated frame plates, means connecting said plates in rigid spaced parallel relation, a pair of opposed elongated jaws pivotally mounted by one end in spaced relation between said frame plates, the facing edges of said jaws having mating notches in the ends thereof remote from their pivoted ends forming a fixed die when said jaws are in parallel relation for receiving said overlapped strapping thereon, a punch adapted to cooperate with said fixed die to punch interlocking tabs in said overlapped strapping resting on said fixed die, said punch being mounted for longitudinal movement between said jaws toward and away from said fixed die, means connected with each of said jaws for holding said jaws together while said punch moves toward said fixed die, and means connected with each of said jaws for moving the same away from each other after said joint has been made, said jaws each having a substantially oval shape opening therethrough, the major axis of each of said openings extending longitudinally of its respective jaw, bearings mounted one in each of said openings for reciprocal linear movement along the major axis thereof in rolling engagement with the walls thereof, said means connected with each of said jaws for moving the same away from each other being connected with said bearings whereby said bearings are moved along their respective openings by said last-named means to pivot said jaws away from each other as said punch moves away from said fixed die.

2. Apparatus as defined by claim 1 in which each of said means connected with each of said jaws for moving the same away from each other includes a pair of spaced elongated links, the links of one pair being rotatably mounted by one end on a shaft extending through and between said pair of frame plates adjacent one edge thereof and extending normal to said shaft one link adjacent each of the two opposite faces of one of said jaws transversely of the opening in said one of said jaws, the links of the other of said pair of links being rotatably mounted by one end on a shaft extending through and between said pair of frame plates adjacent the edge thereof opposite said one edge and extending normal to said last-mentioned shaft one link adjacent each of the two opposite faces of the other one of said jaws transversely of the opening in said other one of said jaws, abutments are on said jaws adjacent the edges of each of said openings remote from the pivoted ends of said jaws adapted to engage and support said links, the bearing in each of said jaws has a stub shaft projecting from opposite sides thereof connected with said links adjacent the opposite faces of said jaws, a pawl is rotatably mounted by one end in the free end of each of said links, a spring is disposed in each of said links with one end projecting therefrom and bearing against the free end of the pawl disposed in the link to constantly urge the free end of the pawl outwardly into the path of said punch, a connecting plate is attached to and extends between the links of each pair intermediate the respective shafts and jaws, and a coil spring is disposed bearing at one end against each of said connecting plates and at the other end against a cap plate extending between said frame plates remote from said connecting plates, a pin attached by one end to each of said connecting plates and extending therefrom through each of said coil springs to an attachment by its other end with each of said cap plates, said coil springs constantly urging said links against said supporting abutments and said jaws toward each other,

said punch has bearing surfaces thereon adapted to engage the outwardly urged end of said pawls as said punch moves away from said fixed die to thereby rotate said links and move said bearings along the walls of said openings to pivot said jaws away from each other.

3. Apparatus as defined by claim 2 in which spaced pairs of eccentric peripheral portions are formed on each of said shafts and said links are mounted one on each of said eccentric peripheral portions, the ends of said shafts project from opposite sides of said frame plates, securing means are disposed on the projecting ends of said shafts to secure said shafts in position and said frame plates in spaced rigid relationship, and the ends of said shafts projecting from one side of said pair of frame plates being formed with a substantially square cross section intermediate said securing means and said one side of said pair of frame plates.

4. Apparatus as defined by claim 3 including indexing means for adjusting the clearance between said jaws, said indexing means comprising an index plate fixedly mounted on said square cross-sectional portion of each of said shafts and abutting said one side of said pair of frame plates, said index plates each having a substantially square center openings therethrough in which the square cross-sectional portion of its respective shaft is snugly received and a plurality of holes therethrough spaced in a substantially circular pattern around the perimeter of its respective shaft, said one side of said pair of frame plates against which each of said index plates abuts having a plurality of holes therethrough spaced around the perimeter of each shaft adjacent the square cross-sectional portion thereof, said last-mentioned plurality of holes each being juxtapositioned with the plurality of holes in said index plates, the number of holes in each of said index plates exceeding the number of holes in the plurality of holes in said one side of said pair of frame plates juxtaposed thereto, said index plates being adjustably rotatable to rotate said shafts to rotate said peripheral eccentric portions thereof to thereby vary the clearance between said jaws, and a pin adapted to be inserted in a pair of holes one in each of said index plates and one in each of said plurality of holes in one side of said pair of frame plates which are aligned after said shafts are rotated to desired position. =0 W 4 9 1*

Claims

2. Apparatus as defined by claim 1 in which each of said means connected with each of said jaws for moving the same away from each other includes a pair of spaced elongated links, the links of one pair being rotatably mounted by one end on a shaft extending through and between said pair of frame plates adjacent one edge thereof and extending normal to said shaft one link adjacent each of the two opposite faces of one of said jaws transversely of the opening in said one of said jaws, the links of the other of said pair of links being rotatably mounted by one end on a shaft extending through and between said pair of frame plates adjacent the edge thereof opposite said one edge and extending normal to said last-mentioned shaft one link adjacent each of the two opposite faces of the other one of said jaws transversely of the opening in said other one of said jaws, abutments are on said jaws adjacent the edges of each of said openings remote from the pivoted ends of said jaws adapted to engage and support said links, the bearing in each of said jaws has a stub shaft projecting from opposite sides thereof connected with said links adjacent the opposite faces of said jaws, a pawl is rotatably mounted by one end in the free end of each of said links, a spring is disposed in each of said links with one end projecting therefrom and bearing against the free end of the pawl disposed in the link to constantly urge the free end of the pawl outwardly into the path of said punch, a connecting plate is attached to and extends between the links of each pair intermediate the respective shafts and jaws, and a coil spring is disposed bearing at one end against each of said connecting plates and at the other end against a cap plate extending between said frame plates remote from said connecting plates, a pin attached by one end to each of said connecting plates and extending therefrom through each of said coil springs to an attachment by its other end with each of said cap plates, said coil springs constantly urging said links against said supporting abutments and said jaws toward each other, said punch has bearing surfaces thereon adapted to engage the outwardly urged end of said pawls as said punch moves away from said fixed die to thereby rotate said links and move said bearings along the walls of said openings to pivot said jaws away from each other.

4. Apparatus as defined by claim 3 including indexing means for adjusting the clearance between said jaws, said indexing means comprising an index plate fixedly mounted on said square cross-sectional portion of each of said shafts and abutting said one side of said pair of frame plates, said index plates each having a substantially square center openings therethrough in which the square cross-sectional portion of its respective shaft is snugly received and a plurality of holes therethrough spaced in a substantially circular pattern around the perimeter of its respective shaft, said one side of said pair of frame plates against which each of said index plates abuts having a plurality of holes therethrough spaced around the perimeter of each shaft adjacent the square cross-sectional portion thereof, said last-mentioned plurality of holes each being juxtapositioned with the plurality of holes in said index plates, the number of holes in each of said index plates exceeding the number of holes in the plurality of holes in said one side of said pair of frame plates juxtaposed thereto, said index plates being adjustably rotatable to rotate said shafts to rotate said peripheral eccentric portions thereof to thereby vary the clearance between said jaws, and a pin adapted to be inserted in a pair of holes one in each of said index plates and one in each of said plurality of holes in one side of said pair of frame plates which are aligned after said shafts are rotated to desired position.