US2281438A - Strap stretching device - Google Patents

Description

April 28, 11,942. c. G. HEsLET ETAL STRAP sTRETcx-IING DEVICE Filed Aug. 7, 1939 2 Sheets-Sheet l April 28,- 1942. -c. G.- HEsLET `ET Al.

STRAP STRETCHING DEVICE Filed Aug. '7,11959 2 Sheets-Sheet 2 Patented Apr. 28, 1942 ,inne

2,281,438 STRAP STRETCHING DEVICE Charles G. Heslet and Edwin C. Layman, Chicago, Iii., assignors to Acme Steel Company, Chicago, Ill., a corporation of Illinois Application August 7, 1939, Serial No. 288,694-

(Cl. 254-51l 12 Claims.

versely bent beneath it, is engaged by a plate or ange carried by one part of the tool which rests upon the box or package about which the strap passes, the end of the strap which is not bent about the seal being held by a, gripping device which is capable of relative movement with respect to the plate or fiange for the purpose of drawing the strap taut around the box or pack-'- age. Heretofore, strap stretching devices of this type have been unsatisfactory because of the tendency ofthe plate or'liange, located between the overiapping strap ends, to shear the lateral edges of the seal under the pressure set up during the stretching operation, and in the copending application of Frederick A. Endress, Serial N0. 272,357, led May 8, 1939, now `Patent Number 2,232,376, granted February 18, 1941, there is described and claimed an improvement adapted to overcome this difficulty by providing means supplementary to the plate or flange for bearing Iagainst one transverse edge of the seal during the stretching operation. In that application, there is disclosed a form of stretching tool in which the improvement embodies a pivoted holding member carried by the head on which theY plate or ange is formed and adapted to rest upon the upper strap end in a position'to bear against the transverse edge of the seal between the lateral edges which are engaged by the plate or flange located between the strap ends. In that device, means are provided for gripping the upper strap. end and for effecting rela-tive movement of the gripping device and the parts which bear against the end of the seal, so that the strap may be drawn taut around a box or package preliminary to deforming the seal and the enclosedl strap ends to provide an interlocking joint.

The principal object of the present invention is to provide a strap stretching tool of the pusher bar type with means for cutting off the strap adjacent the seal after the strap has been drawn taut around the box or package and. sub-sequent to the formation of an interlocking joint by deforming the seal and the enclosed strap ends.

The present invention involves the discovery thaty this operation of severing the strap may be quickly and conveniently eiected by forming the additional holding member, disclosed in said pending application for engaging the transverse edge ofA the seal on the upper side of the strap, of hard metal having an edge adapted to bear against the upper strap end adjacent the seal, so that after the joint has been formed, land while the upper strap end between the seal and the gripping device is still under tension, the entire strapstretching device may be tilted upwardly with the end of the holding member bearing against the upper edge of the seal as a fulcrum, thus bending and stretching the upper strapend about said edgeand thereby causing the upper strap end to be broken or cracked oli in proximity to the seal. This severing of the strap may be, effectecl in Va single tilting. movementlof the strap stretching device, and the-strap is broken oifso closeto the end-of the seal that no projecting end is left to injure the hands of the operator, or to catch on surrounding objects. In its preierred form, the present invention employs a, pivoted holding member, such as thatdisclosed in the said application of Frederick A. Endless, which is formed of hard metal and which. has an angular transverse lower edge at its free end adapted to bear upon the upper portion of the strap in proximity to the end of the seal. Otherr features and advantages of the invention will appear more fully hereinafter.

The nature of the invention will be under-v stood from the following specicationtaken with the accompanying drawings in which one ernbodiment is illustrated. In the drawings,

Figure l shows a top plan view of a strapv stretching device embodying one form of the present invention;

Fig. 2 showsv a perspective View of one type of interlocking joint which may be used to unitethe. overlapping strap ends after they have been drawn taut by the stretching device illustrated' in Fig. 1;

Fig. 3 shows. a side elevation of the strap stretching device illustrated in Fig. 1 during the operation of drawing the strap taut `and prior t0 the formation ofthe interlocking joint;

. Fig. 4 isa partial side elevation similar to that oi Fig. 3, illustrating the conditionY of the seal after the interlocking` joint has been formed and showing the position of` the strapstretching device when it is tilted upwardly t0 shear or break oli the strap adjacent tothe seal;

Fig. 5 shows a longitudinal section taken on the line 5-5 of Fig. 1, illustrating some of the operating mechanism of the strap stretching device;

Fig. 6 is a partial side elevation of the strap stretching device looking upwardly, as viewed in Fig. 1;

Fig. 7 is a vertical section taken on the line 1-1 of Fig. 3, showing an end elevation of the strap stretching device;

Fig. 8 shows a partial sectional view on the line 8-8 of Fig. 5; and

Fig. 9 shows a partial side elevation similar to that of Fig. 3 with the operating lever in a position wherein the pawl is in engagement with the gear wheel forming a part of the operating mechanism.

The invention is shown in the drawings as being employed in drawing a strap I!) taut around a box or package II. The strap IB, which may be a flexible steel strap such as that ordinarily f employed for reinforcing boxes or packages, has one end portion Illa which is threaded through a metallic seal I2 in the form of a flat sleeve-like member. The extremity IIlb of this portion of the strap is reversely bent about the seal I2 and bears against the upper surface of the box or package II. The other end portion Ic of the strap Ill also passes through the seal I2, the two portions of the strap being preferably threaded through the seal in overlapping relation before the looped portion between the end portions of the strap is passed around the box or package. The purpose of the strap stretching device, which is designated generally by the numeral I3, is to draw the strap IIJ taut around the package Il,

edges to provide opposed pairs of cuts I4 which i permit the intervening metal to be deflected out of the plane of the seal and the strap ends to form lugs I5, thus providing abutting shoulders on the seal and the strap ends which prevent relative endwise movement of these connected 1 parts.

The strap stretching device I3 comprises a head I6 carried at the end of a rack bar II and provided with a flange Ia which extends laterally from the head and between the end portions Illa and I0c of the strap, as best shown in Fig. 3.

This flange Ia is provided with a tapered end portion Ib which terminates in a thin edge IBC arranged to bear against the opposite edges |211 of the seal at opposite sides of the strap, thus holding the end portion Ia of the strap against movement toward the right, as viewed in Fig. 3, during the strap stretching operation. The head I6 also carries a holding member or abutment I8 which is formed of hard metal and which is adapted to rest upon the upper side of the end portion IIJc of the strap in proximity to the seal. This member I8 has a transverse end face IBc of the seal I2.

proximity to the end of the seal. The edge I8c may preferably be more or less sharp, but a sharp edge is not essential to the severing of the strap which is effected by stretching and breaking it about this edge. The face I8a is adapted to bear against the upper transverse edge |212 of the seal between the lateral edges I2a which are engaged by the plate or fiange Ia. The end portion IIIc ofthe strap passes through the slot I9 between the iiange Ilia and the lower surface |81) of the member I8. This slot is preferably formed by mounting the member I8 for relative movement with respect to the member I 6, so that it may be moved toward and from the flange Ia to permit the insertion of the strap portion I0c beneath it.

In the embodiment illustrated, the member I8 is in the form of a pvoted dog having a hub portion I 8d which is mounted to pivot about a pin 20 passing through an aperture in the head I6 and provided with a transverse groove in its side for engagement by a holding pin 22 fixed in an aperture in the head, as shown in Fig. 5, to serve the double purpose of securing the pin 20 in place and also of securing the rack bar I'I within the head I6. The holding member or abutment I8 is inclined downwardly and toward the left longitudinally of the strap from its pivot pin 20, as viewed in Fig. 3, so that the reaction of the end thrust of the member I8 on the seal I2 will have a component tending to maintain the member I8 in contact with the upper end portion of the strap. The head I6 is provided with a flange ISd which overlies the holding member or abutment Y I8, and the part Id and the member I8 are provided with registering recesses to receive the ends of a coil spring 23 which normally presses the member I8 downwardly into a position where it engages the upper side of the strap I0 in a location where it is also capable of abutting against the end of the seal I2.

At certain times, and particularly when the support of the tool on the box or package is limited there is a tendency of the end portion I0c of the strap at the right of the seal, as viewed in Fig. 3, to move upwardly away from the flange Ilia and to bear against the underside of the holding member I8 with a possibility that the pressure may raise the member I8 to prevent it from maintaining its engagement with the end To overcome this possibility, the underside of the member I8 is concaved upwardly between its ends as shown at If so that the strap mayV bow upwardly without exerting substantial pressure on the member I8 tending to tilt it upwardly. In addition, the hub portion of the member I8 is provided with a projection or shoulder I8e forming a lever arm extending downwardly toward the strap at the right of a vertical plane passing through the axis of the pin 2U, so that if the strap does bow upwardly, it

will press against this projection I8e and thus apply to the member I8 a force opposing any tendency of the extremity I8a thereof to move upwardly out of engagement with the seal.

which is inclined upwardly and slightly toward The end portion Ic of the strap extends over the upper surface of the flange Ia and over another flange 2Lla which projects forwardly from a frame or housing 24 having a passage of rectangular cross section therethrough which is slidably fitted by the rack bar I'I. 'I'his housing 24 is provided with an upwardly extending arm Zlib provided with a handle 25 which may be engaged by one hand of the operator during the manipulation of the tool. The housing 24 is also provided with another forwardly extending flange 24c, located somewhat below `the plane of the body portion of the housing, as shown in Fig. 3, which is intended to rest upon the upper side of the strap l) above the package, in the event that the box or package is large enough to support the housing 26 at this point. The end portion lc/ of the strap is held in fixed relation to the housing 213 by a gripping dog 26 which is pivotally mounted upon a pin 27 extending through the housing 2d, the head of the pin overlapping the gripping dog and the rear extremity thereof being engaged by a cotter pin 28, as shown in Fig. 6, for preventing its accidental removal. The housing 24 is provided with a boss or flange 24d which overlies the gripping dog 26 and which has an arcuate surface 24e forming a bearing for the correspondingly curved surface of the upper end of the gripping dog, thus relieving the strain upon the pin 21 when tension is put upon the strap l). 'I'he gripping dog 26 is inclined downwardly and toward the'right, as viewed in Figs. 3 and 9, and it is provided at its lower end with a gripping surface 25a adapted to engage the upper surface of the end portion lila of the strap above the flange 26a of the housing. 'Ihis gripping dog is normally forced into engagement with the strap on the nange 24a by a coil spring 29 which engages registering recesses in the upper inclined face of the gripping dog and in a shoulder 2M formed on the housing 24,

In order to effect relative movement of the gripping dog 25 and the flange 2da with respect to the extremity of the strap which is held by the seal l 2 in fixed relation to the flange Ilia and the member IB, the housing 2e is capable of being moved bodily along the rack bar I1, and this movement is effected through the actuation of a gear Wheel 33 which has teeth 30a meshing with the rack teeth lla formed on the upper side of the rack bar, as shown in Fig. 5. This gear wheel 3Q is mounted to revolve about a pin or axle 3l having a head Sla at one end provided with a at side which bears against one at edge of the previously described shoulder 24j, as shown in Fig. 9. At its other end, the pin 3| is threaded for engagement by a nut 32, shown in Fig. 1. The gear wheel 3E) is mounted between the flanges 33a formed at the lower end of an operating lever 33 which carries a ball or handle 34 at its outer end. The flanges 33a of this lever are apertured for pivotal engagement with the pin 3! and when the lever 33 is rocked in the appropriate direction by the pin 3l, the gear wheel 33 is adapted to be rotated through the agency of a pawl 35 which is pivotally mounted in the anges 33a and which is provided between these flanges with a portion 35a of semicircula-r cross section, the edges of which constitute teeth, one of which is adapted to enter the spaces between the teeth 30a of the gear wheel. When this tooth engages a space between the gear teeth, as shown in Fig. 5, movement of the lever 33 toward the right, as viewed in that figure, will rotate the gear wheel 3D in the proper direction to move the housing 24 and the gripping dog 26 toward the right, as viewed in Figs. 3 and 5, thus drawing the strap taut.

The pawl 35 is normally rotated in a direction to cause its tooth to engage the gear teeth by a coil spring 36 which surrounds the projecting reduced end of the pawl 35 at the rear side of the lever 33, one end of the spring passing through a transverse aperture in the end of the pawl and the other end of the spring -engaging a lug v33h which is formed on the side of the lever, as shown in Fig. 6. The lever 33 may be given a reciprocating movement in order to rotate the gear wheel 30 by successive increments, and during each movement of the lever 33 toward the left, as viewed in Fig. 5, the flat face of the semicrcular portion 35a of the pawl will pass over the outer ends of the teeth 30a. During'each reverse movement of the lever 33,' the gear wheel 30 is held against reverse rotation by one of two similar detents 31 which are arranged side by side and pivotally mounted between the side walls of the housing upon the pinZ'l which carries the gripping dog 2S. Each detent has a tooth 31a adapted to enter between two of the teeth 30a of the gear wheel and it also has an angularly disposed arm 31h extending upwardly at the left of the lever 33, as viewed in Fig. 5. A coil spring 38 is mounted between the arm 37b of each detent and the end wall 213g of the housing, each spring having its ends mounted in registering recesses in these opposed parts. The detents are thus forced into normal engagement with the teeth of the gear wheel 30. The arm of one detent which carries its tooth 31a is longer than the corresponding arm of the other detent so that they are adapted to engage alternate teeth of the gear wheel to prevent reverse rotation thereof, this arrangement being adapted to cause the gear wheel to be held regardless of the precise position it occupies when released by the pawl 35.

Upon extreme movement of the lever 33 toward the left, as viewed in Figs. 3 and 5, both detents 31 are adapted to be released from the gear wheel 3&2 due to the engagement with the arms Sib of the lower end face 330 of the lever just above the flanges 33a which causes the detents to be rocked about their pivot against the compression of the springs 38. The pawl 3% may also be released from its engagement with the gear wheel 39, at the time of releasing the detents 3! there-from, in order to allow a free rotation of the gear wheel 3B and a consequent free movement of the housing or frame 2li on the rack bar Il. This release is effected by the engagement of the iiat surface 35o on the projecting end of the pawl with a shoulder 24h formed on the frame 24 above the pivot pin 3l, as shown in Figs. 3 and 9. As .the lever 33 is moved toward the left from the position shown in Fig. 9, the flat surface 35C rides over the shoulder 2th, thus turning the pawl so that its tooth passes out of engagement with the teeth of the gearwheel. As the motion of the lever toward the left continues, the flat face 35C occupies a position parallel to and in proximity to the upper flat face 26h of the side wall of the housing, as shown in Fig. 3, thus` holding the pawl positively out of engagement with the teeth of the gear Wheel. When the parts are in the relative position shown in Fig. 3, the housing or frame 24`may be moved freely on the rack bar Il through the agency of the handle 25 in order to locate the gripping dog 28 in the desired position for engagement with the `upper end portion 10c of the strap. When the gripping dog 26`has been properly positioned and the strap is held thereby against the shoulder 24h, of the frame or-housing 24, the parts are in readiness for drawing the strap taut and upon movement of thev lever 33 toward the right. as viewed in Fig. 3, it will reach a position where the pawl is released by the shoulder 2th. so that the spring 36 will then lrestore the pawl into engagement with the teeth of the gear wheel, thus permitting continued movement of the lever in the same direction to effect rotation. of the gear wheel and a consequent movement of the frame 24 on the rack bar Il with a resulting stretching of the strap so that it is drawn taut around the package. Of course, this tightening of the strap may be effected by several reciprocating motions of the lever 33 without causing the pawl to be released by the engagement of its suriace 35a with the shoulder Zilli. During this operation, the end Illa of the strap is held by engagement of the ange IIb with the sides cf the seal and also by the engagement of the lower part of the flat end face of the holding member I8 with the upper transverse edge of the seal, so that the strap may be drawn taut to any desired degree without injure ing the seal i2 or interfering with its use in the formation of an interlocking joint, such as that shown in Fig. 2.

After the interlocking joint has been formed and while the upper end portion of the strap between the seal I2 and the gripping dog 25 is still under tension, the entire strap stretching device is tilted upwardly and toward the left as viewed in Fig. 3 until it reaches a position such as that shown in Fig. 4, with the surface Ia oi the member I8 bearing against the transverse edge I2b of the seal I2 and with the upper strap end Ic bending and stretching about the angular edge I8c of the member I8 adjacent the seal. By this action, further tension is put upon the strap adjacent the seal while it is still under tension from the stretching operation, so that it is stretched and bent around the edge ISC of the member I8, with the result that the strap breaks or snaps on" adjacent the seal where the edge I8c bears against it, thus leaving a very short end that will not catch on surrounding objects or injure the hands of the workmen. Having completed the joint and severed the strap, the stretching device may be removed from the supply portion of the strap in readiness for a new operation upon another box or package.

Although one form of the shown and described by way of illustration, it will be understood that it may be constructed in various other embodiments coming within the scope of the appended claims.

We claim:

1. The combination in a strap stretching device, of means for effecting relative'movement of overlapping end portions of a strap passed around a package to draw the strap taut, and

means located at one extreme end of said device and adapted upon a movement of said device bodily with respect to the package for severing one end portion of the strap.

2. The combination in a strap stretching device, of means for engaging a seal attached to one overlapping end of a strap passed around a package, means for holding the other end portion of the strap, means for effecting relative movement of said first named means and said second named means for drawing the strap taut around the package, and means comprising a portion of said rst-named means coacting with said seal for severing the strap in proximity to the seal.

3. The combination in a strap stretching device, of means for engaging a seal attached to one overlapping end of a strap passed around a package, means for holding the other end portion of the strap, means for eiiecting relative movement oi said first named means and said invention has been second named means for drawing the strap taut around the package, and means actuated by a tilting movement of said device about the end of the seal for severing one end portion of the strap adjacent the seal.

4. The combination in a strap stretching device, of means for engaging a seal attached to an overlapping end of a strap passed around a package, means for holding the other end portion of the strap, means for eiecting relative movement of said first named means and said second named means for drawing the strap taut around the package, and means for severing the strap in proximity to the seal, said iirst named means having a part adapted to bear against the upper end portion of the strap and another part adapted to bear against the seal whereby upon tilting said device away from the package the upper strap end is stretched and broken.

5. The combination in a strap stretching device, of means having a slot to receive one of two overlapping ends of a strap passed around a package, said means being adapted to abut against the end of a tubular seal to which the other of said strap ends is attached and through which both of said strap ends extend, and means for moving said rst. named strap end with respect to said seal to draw the strap taut around the package, said rst named means having an edge adapted to bear against the outer strap and a surface adapted to bear against an outer edge of the seal whereby the tilting of said device away from the package about said edge of the seal breaks the outer strap end where it is engaged by said edge of said first named means.

6. The combination in a strap stretching device, of means adapted to extend between two overlapping ends of a strap passed around a package and to bear against the end of a seal surrounding said strap ends and attached to one of said strap ends, means adapted to bear against said end of said seal on the opposite side of one of said strap ends from said last named means, and means for drawing the strap taut around the package by pulling on the strap end which is not attached to said seal, said second named means being formed to bear against the outer strap end and being provided with a surface bearing against an edge of the seal so that when said device is tilted away from the package said surface and the engaged portion of said seal coact to stretch and break the outer strap end.

7. The combination in a strap stretching device, of a member adapted to extend between two overlapping ends of a strap passed around a package and to bear against one end of a seal surrounding said strap ends and attached to one of them, a second member movably mounted on said first named member and adapted to bear against said end of said seal on the side of one of said strap ends opposite said first named member, means for gripping the end of the strap which is not attached to said seal, and means for effecting relative movement of said gripping means and said members to draw the strap taut around the package, said movably mounted member having a hard metal part adapted to engage the upper strap end and being provided with means for tensioning the upper strap end about said hard metal part until said upper strap end is broken in response to tilting of the device bodily away from the package while the strap between said seal and said gripping means is under tension.

8. The combination in a strap stretching device, of a member adapted to extend between two overlapping ends of a strap passed around a package and to bear against one end of a seal surrounding said strap ends and attached to one of them, a second member pivotally mounted on said i'lrst named member and adapted to bear against said end of said seal on the side of one of said strap ends opposite said rst named member, means for gripping the end of the strap which is not attached to said seal, and means for effecting relative movement of said gripping means and said members to draw the strap taut around the package, said pivotally mounted member having a hard metal part provided with a transverse edge adapted to engage the upper strap end and an end surface adapted to bear against an outer edge of the seal upon tilting the device bodily away from the package while the strap between said seal and said gripping means is under tension, whereby the strap is stretched and broken where it is bent about said transverse edge.

9. In a device for stretching a strap passed around a package and having overlapping portions one of which is attached to a seal, the seal being provided to secure the overlapping portions of the strap together, means `including a member having a face engaging said seal for effecting relative movement between the overlapping portions of the strap, thereby to tension the strap about the package, said member being provided with an edge bearing against one of the overlapping portions of the strap, and means including the face of said member coacting with the engaged portion of said seal after the overlapping portions of the strap have been secured together by said seal for increasingly tensioning said one overlapping portion of the strap about said edge until said one overlapping portion of said strap is severed at its point of engagement with said edge.

10. In a device for stretching a strap passed around a package and having overlapping portions one of which is attached to a seal, means including a member having a face engaging one end of said seal for effecting relative movement between the overlapping portions of said strap, thereby to tension the strap about the package, said face terminating in an edge bearing against one of the overlapping portions of the strap, and means including the face of said member coacting with the engaged end cf said seal for increasingly tensioning said one overlapping portion of the strap about said edge until said one overlapping portion of said strap is severed at its point of engagement with said edge in response to pivotal movement of said device about said one end of said seal.

11. The combination in a strap stretching device of means for eiecting relative movement of overlapping end portions of a strap passed around a package to draw the strap taut, means for securing said overlapping end portions of said strap together while said strap is under tension, and means comprising a portion of said device actuated by movement of said device bodily with respect to said device for increasingly tensioningpne end portion of the strap and for bending said one end portion of the strap about a portion of said device until it is severed from the portion of said strap which encircles said package.

12. The combination in a strap stretching device which includes an element having an edge, of means for effecting relative movement of overlapping end portions of a strap passed around a package to draw the strap taut, means for securing said overlapping end portions of said strap together while said strap is under tension, and means actuated by movement of said device bodily with respect to said device for increasingly tensioning one end portion of the strap and for bending said one end portion of the strap about said edge until it is severed at the point of engagement with said edge. i

CHARLES G. HESLET. EDWIN C. LAYMAN.

Images