US2751939A - Strap-tensioning tool - Google Patents

Description

June 1956 E. c. BARKER STRAP-TENSIONING TOOL 4 Sheets-Sheet 1 Filed NOV. 5, 1951 I N V EN TOR. 1 772652 6". fiazr/zer;

June 26, 1956 E. c. BARKER STRAP-TENSIONING TOOL.

4 Sheets-Sheet 2 Filed Nov. 5 1951 June 26, 1956 E. c. BARKER STRAP-TENSIONING TOOL 4 Sheets-Sheet 5 Filed NOV. 5, 1951 iii-NI i 1 United States Patent STRAP-TENSIONING root.

Ernest C. Barker, La Grange Highlands, 111., assignor to United States Steel Corporation, a corporation of New Jersey Application November 5, 1351, Serial No. 254,875

6 Claims. (Cl. 140-936) This invention relates to a portable heavy-duty tool for use in tensioning a strap about an object or group of objects with the ends of the strap arranged in overlapped relation to receive a seal.

The purpose of the invention is to provide, in a tool of this type, improved strap-gripping, tensioning and shearing means which combine to render the tool not only highly eflicient but very simple and easy to load and manipulate.

A preferred embodiment of the invention is disclosed herein by way of exemplification but it will of course be appreciated that the invention is capable of being embodied in other structurally modified forms coming equally within the scope of the appended claims.

The tensioning means disclosed herein is claimed in my copending application Serial No. 543,573, filed October 28, 1955, which is a division hereof.

In the accompanying drawings:

Fig. 1 is a front view of the new tool, showing the manner in which the overlapped ends of a strap looped about an object are adapted to be threaded into the tool preparatory to effecting the desired tensioning operation;

Fig. 2 is a plan view of the tool;

Fig. 3 is another front view of the tool, on a larger scale;

Fig. 4 is a fragmentary rear view of a portion of the tool at the location of the tensioning mechanism;

Fig. 5 is an end view of the tool, with portions broken away;

Fig. 6 is a fragmentary vertical section through the gripping and shearing mechanisms of the tool, taken on approximately the line 66 of Fig. 5;

Fig. 7 is a fragmentary vertical section through the tensioning mechanism, taken on approximately the line 77 of Fig. 2; and

Fig. 8 is a section similar to Fig. 7 but sows the tensioning mechanism in its fully released position.

My improved tool is a small but powerful device adapted to be placed against the top or other surface of an object 10 about which a strap 11 is to be secured.

Described generally, the tool includes an elongated frame 12, a gripping mechanism 13 near the left end of the frame for holding one end 14 of the strap stationary while the other end 15 is being pulled to put the looped part 16 under the desired degree of tension, 21 tensioning mechanism 17 to the right of the gripping mechanism for engaging and pulling the end 15, and a shearing mechanism 18 associated with the gripping mechanism for cutting olf the end 15 after the overlapped ends have been securely fastened together by means of a seal 19.

The seal 19 is adapted to be secured in place by means ice of a separate sealing tool of any desired type after the strap has been tensioned. The seal may be telescoped over or otherwise arranged in embracing relation to the overlapped ends of the strap either before or during the threading of such ends into the tensioning tool, in either event being preferably located about the overlapped ends as close as feasible to the left end of the tool, as shown in Fig. 1.

The frame 12 of the tool includes a base with a low flat forwardly projecting foot portion 20. The stationary end 14 of the strap is adapted to be placed over the foot portion 20 and clamped immovably against the same by the gripping mechanism 13.

The gripping mechanism 13 includes a dog 21 located directly above the foot portion 20. The dog 21 is provided on the bottom thereof with serrations 22 which bite into the upper surface of the strap end 14 when the dog is moved downwardly, whereby to hold said end against movement to the right. The dog 21 is provided at the upper right hand corner thereof with a hub 23 which fits in an arcuate socket 24 in the upper portion of the frame and is pivotally mounted for free movement on a pin 25 fixed in the frame in concentric relation to the socket.

The rear face of the dog fits into a shallow recess 26 in the front face of an upstanding wall 27 of the frame. When the dog 21 is swung upwardly away from the foot portion 20 the upper face 28 of the dog will abut with the top of the recess 26 to limit such upward movement.

When the dog 21 is released for downward movement, it is forced downwardly by a spring 29 into gripping engagement with the end 14 of the strap. The spring 29 fits in a vertical bore 30 in the frame above the recess 26 and is compressed between a screw plug 31 in the upper end of that bore and the upper face 28 of the dog.

When the dog 21 is raised into its uppermost position it is automatically locked in that position by means of a small pin 32 which is forced under spring pressure into a recess 33 in the rounded surface 34 of the hub 23 on the dog. The upper end of the pin 32 is pivotally connected to one arm 35 of a small bell-crank 36 which is in turn pivoted in a slot 37 in the top of the frame on a pin 38. The other arm 39 of the bell-crank is engaged from below by a plunger 40 mounted in a bore 41 and pressed upwardly by a coil spring 42. The bell-crank 36 has a handle 43 which, upon being turned toward the right, will retract the pin 32 to release the dog and allow the latter to swing downwardly into gripping engagement with the end 14 of the strap. As the serrations 22 on the dog are located in a plane to the left of the pivotal axis of the dog, tension on that end of the strap toward the right will act to tighten the grip of the dog.

The dog 21 is provided, immediately above the serrated lower face thereof, with a forwardly opening slot 44 for freely accommodating the other end 15 of the strap in its passage toward the right to the tensioning mechanism 17. The slot 44, which is disposed at a slight inclination to avoid deflecting, or being deflected by, the inclination of the end 15 resulting from the relatively elevated location of the tensioning mechanism, is beveled along its upper and lower front edges 45 and 46 to facilitate insertion of the strap from the front.

The shearing mechanism 18, while acting to cut off the end 15 of the strap engaged by the tensioning mechanism 17, is structurally associated with the above described gripping mechanism 13. It includes a shear blade 47 which reciprocates vertically a guideway 48 formed in the left side of the dog21 above the left end of the forwardly opening slot 44. The blade 47 and the guideway 48 for the same are preferably of T-shaped or other laterally interlocking cross section. The lower end of the blade has a knife edge 49 which is preferably set at an angle and cooperates with the lower edge 50 of the left end of the slot 44 for severing the end 15 of the strap after the seal 19 has been'permanently secured to the overlapped and tensioned ends.

Theblade 4 7' is provided on "its inner face with rack teethf51 meshing with a pinion 52 rotatable in a cavity 53in the dog 21; The pinion 52 is formed on a shaft 54 journalled in'a bore 55 in the dog, at a point some distance tothe left of and'below'the pivotal axis thereof, and the front end of the shaft 54 is secured to a sector-shaped hub 56 formed on the lower end of an upwardly extending hand lever 57. V p

' When the hand lever 57 is swung to the left it will act through the pinion and rack connection to force the blade 47 downwardly to shear off the. end 15 of the strap, and when itis subsequently swung to the right it will first return the blade 47 to its raised position and will then move the dog 21 upwardly away from the foot portion 20 into the position in which the dog is automatically locked by he pin T he 'rear face of the hub 56 on the hand lever 57 is positioned against the front face of the dog 21 and is provided with a rearwardly facing arcuate groove 58 concentric with the pivotal axis of the lever. A depression 59 is formed in the groove at the left end thereof. The groove servesas a runway for the front end of a forwardly springpressed' pin 60 slidably mounted in the dog at the radius of the groove and terminating in a conical tip 61 adapted to' fitindepression 59. V

' 'When dog 21 is in engagement with strap end 14 and the hand lever 57 is moved to the left relative to the dog 21 to lower the shear blade47, the pin 60 must first be forced out of depression 59, and then will ride in the groove 58. The resistance to turning of the lever thus offered prevents accidental downward movement of the blade and possible nicking of the inner edge of'the looped part of the strap 16. Depression 59 thus prevents r lessens the chance of any accidental movement of the lever '57 which might drive the blade prematurely into engagement with the strap.

' 'When' the hand lever 57 is moved to the right relative to the dog 21 to retract the shear blade 47, the pin 60 will enter depression 59 when the blade reaches its fully retracted position and will thereafter hold it in that position. Further movement of the hand lever relative to the dog will'be'prevented by engagement of the pin 60 with the left end of the slot 58. As a result, the dog will be raised into its retracted position, in which it will be automatically locked by the pin 32.

The tensioning mechanism 17 includes a shaft 62 which is located to the right of the'dog 21 and is'journall'ed in a b ore63 inwall 27 of the frame 12. The front end 65 of the shaft projects forwardly into the plane of the dog 21 and is'pro'vide'cl with a forwardly opening diametral 'slot 66 in which the end of the strap is adapted to be positinned.

' When the shaft 62 is rotated in a counterclockwise direction, by the ineans hereinafter described, the slotted forwardlyprojecting end. 65 of the shaft, which constitutes a tensioning head, will wind'the end 15 of thestrap on such headand pull the looped section 16 of the strap tight aboutthe object or objects being banded, with any desired degree of tension.

A small stud 67, which projects forwardly from the frame at a pointabove and slightly to the right of the tensioning head 65, is adapted to engage with the free tip of theend 15 of the strap to deflect the same downwardly when the head is roated, whereby to prevent such tip from moving to' the left into a place where it might interfere 4 w t eit e t hand l e 57 or the handle 9f the gripping mechanism.

Behind the upright portion 64 of the frame in which the shaft 62 is journalled, the shaft extends rearwardly and has a squared portion 68 of reduced diameter on which a ratchet wheel 69 is fitted non-rotatably. Behind the wheel 69 the shaft 62 has a circular portion 70 of still smaller size journalled in a bore 71 in a bearing bracket 72' at the rear edge of the base. The shaft 62 is freely rotatable in wall 27 and bracket 72 but is held against endwise movement by a knurled hand knob 73 keyed to the rear end of the shaft. The knob 73 is held in place by a nut 74 screwed on the shaft behind the knob.

The shaft 62 is adapted to be rotated in a counterclockwise direction by means of a long hand lever 75. The hand lever 75 consists of a clevis head 76 and a tube 77 exteriorly knurled adjacent its outer end to provide a suitable hand grip 78. The head 76 is secured to the inner end of the tube 77 and the spaced arms 79 and 80 thereof span the ratchet wheel 69 and are journalled for free rotation on the circular portions of the shaft on each side of the latter, thus providing a free pivotal mounting for the hand lever 75.

A driving pawl 81 is pivotally mounted in the head 76 between the arms 79 and 30 of the latter on a pin 82 to which it is keyed, and is pressed into one-way driving engagement with the teeth 83 of the ratchet wheel by a coil spring 84.

The ratchet wheel 69 is normally prevented from turning in a clockwise direction by a pair of holding pawls 8 5. and 86 pivotally mounted on the base of the frame 12 by a pin 87. The pawl points 88 and 89 are located at different distances from the pivotal axis of the pawls, and but one of the pawls locks with the ratchet wheel at a time. This provides holding positions twice the number of teeth 83 on the ratchet wheel, thereby permitting such teeth to be made larger and consequently stronger; The holding pawls and 86 are pressed into one-.way locking engagement with the ratchet Wheel 69 by coil springs 96 compressed between extensions 91 and 92 on the pawls and an underlying boss 93 on the frame 12..

When the hand lever 75 is swung toward the right beyond its normal working range into the extreme position shown in Fig. 8, a flat 94 formed on the rear end of the pivot pin 82 to which the driving pawl 81. is at tached will engage a shoulder 95 on bracket 72 at the rear edge of the frame 12 and will rock the pin 82 far enough to disengage the pawl 81 from the ratchet Wheel.

69, as shown in Fig. 4. At the same time a shoulder 96 on the bottom of the head 76 will engage the extensions 91 and 92 on the holding pawls 85 and 86 and willrforce them downwardly into contact with the boss 93' on the frame, thereby disengaging both of the holding pawls from the ratchet wheel 69. In this extreme down position of the hand lever 75, the ratchet wheel is free to turn in either direction and the tensioning head 65 can therefore be easily adjusted by knob 73 to properly position the slot 66 therein to receive the strap end 15.

The hand lever 75 is normally prevented from being swung down into this extreme position, however, by means of a stop pin 97 extending laterally from head 76 through a slot 98 therein. Pin 97 is adapted to strike a cushioned upstanding stud 99 carried by the frame 12, as shown in Figure 7. The stud 99 extends upwardly through a bore in a raised portion 100 of the frame and is supported by a bushing screwed into the bottom of the bore, on a shock-absorbing pad 101.

The stop pin 97 is shiftable lengthwise of the hand lever 75 in the slot 98, being carried by a push rod 102 slidably supported in bores 103 and 104 in the head 76 and extending through the tube 77 to the outer end of the hand lever. The rod 102 is urged axially toward the outer end of the hand lever by a compressed coil spring 102a and has an exposed push button 105 slidably mounted in the end of the hand lever.

In the normal position of the pin .97 shown in Fig. 7, it will abut .the stud 99 and prevent the hand lever from being lowered to the extreme position shown in Fig. 8, but when the push button 105 is depressed the pin 97 will be shifted inwardly clear of the stud 99, whereupon the hand lever may be moved all the way down to completely disengage all pawls from the ratchet wheel 69. As the hand lever is moved downwardly into its extreme position the lower end of the pin 97 will cam against an inclined surface 106 on the raised portion 100 'of the frame, which will not only act to complete the inward shifting move mentof the pin 97 but-will act to thereafter maintain the latter in that position.

The inner end of the rod 102 projects inwardly beyond the portion of the head 76 in which it is slidably mounted, 1n axial alignment with an extension 107 on the driving pawl 81, and when the rod 102 is pushed in as far as it will go, beyond the position shown in Fig. 8, which may be done by means of the push button 105 in any position of the hand lever 75, the inner end of the rod will rock the driving pawl 81 and disengage it from the ratchet wheel 69 without disturbing the locked engagement of the holding pawls 85 and 86 with the ratchet.

To afiord adequate stability for the tool against a supporting surface and yet permit the tool to be used in tensioning straps about small as well as large objects, the base of the frame 12 is extended to the right to a point beyond the tensioning head 65, and has an opening or cut-back 108 through which the looped section 16 of the strap can be passed if the object being handed presents but a short supporting surface. Beyond the opening 108 the frame is provided with a second foot portion 109 over which the looped section 16 of the strap is adapted to be also passed. At the rear of portion 109 is a shoulder 110 in line with the front face of wall 27 for engagement by the rear edge of the looped section 16 of the strap, to prevent the tool from turning at an angle to the plane of the looped section.

At the left end of the tool, just below the level of the forwardly opening slot 44 in the gripping dog 21, a forwardly projecting stud 111 is provided for limiting any upward movement of the strap end 15 in such slot, which movement might otherwise tend to unseat the dog 21 from its gripping engagement with the strap end 14, particularly at the beginning of the tensioning operation while the strap is still under little if any tension.

The manner in which the improved machine is adapted to be used will now be briefly summarized.

After the end 14 of the strap has been placed under the dog 21 the handle 43 is flipped to the right, thereby permitting the dog to be forced down into clamped engagement with that end of the strap by spring 29. The seal 19 may be sleeved over or otherwise loosely associated with the end 14 of the strap either before or after the latter has been placed under the dog 21, whichever is more convenient.

The other overlapping end 15 of the strap, after being threaded through or otherwise associated with the seal 19 over the end 14 of the strap, is then placed in the slot 44 in the dog 21 and in the slot 66 in the tensioning head 65. If the slot 66 does not happen to be in the proper angular position to receive the end 15, it can be turned easily in either direction by pressing in on the push button 105, lowering the tensioning lever 75 into its extreme down position and then turning the hand knob 73.

The lever 75 is then oscillated left and right, causing the head 65 to turn step-by-step in a counter-clockwise direction, thereby wrapping the end 15 of the strap around it. The extent to which the lever 75 will be swung to the left, or the number of times it will be oscillated will vary with the amount of slack present in the looped section 16 of the strap and the amount of tension desired.

After the desired tension has been established and seal 19 has been crimped to the overlapped ends of the strap by means of any suitable sealing tool, the end 15 of the strap is severed adjacent the seal by swinging the shear lever 57 toward the left. As soon as the end 15 has been cut, the shear lever 57 is swung back to the right, which movement of the lever will first act to reset the blade 47 in its retracted position and will then act to lift dog 21 into its raised position, where it will be heldby the pin 32 in readiness for the next strapping operation.

If, at any time during the tensioning operation the position reached by the tensioning lever 75 is not a convenient one in which to apply the required amount of pressure, and it is desired to advance the position of that lever relative to the tensioning head 65, it is merely necessary for the operator to press in on the push button 105, whereupon the driving pawl 81 on the lever will be disengaged from the ratchet wheel 69 and the lever may be moved forwardly into a more convenient position.

If it becomes necessary to temporarily relieve the tension on the strap before the seal is crimped, in order to rearrange the same with respect to the edges of the object or the corner clips sometimes used, this can easily be done by moving the tensioning lever 75 all the way down to the right, with the push button pressed in, thus causing holding pawls 85 and 86 to be disengaged from the ratchet 69. In the normal operation of lever 75 it is prevented from being moved all the way down to the right by the stop pin 97, which prevents holding pawls 85 and 86 from being unintentionally released from the ratchet wheel 69.

I claim:

1. In a tool for use in tensioning a strap about an object with the ends of the strap arranged in overlapped relation to receive a seal, a base having a forwardly projecting portion over which one of the overlapped ends of the strap is adapted to be positioned, a gripper pivotally mounted on the base in vertically spaced relation to said portion for movement downwardly and laterally in an arc in a direction opposite the direction of projection of said strap end into clamped engagement with the latter, said gripper being provided above the strap gripping portion thereof with a forwardly opening slot for the passage of the other end of the strap, which other end is adapted to be engaged and pulled by an associated tensioning device, a reciprocating cutter mounted on the gripper above said slot for shearing coaction with the edge of the slot to cut the end of the strap passing through the same, a rack associated with the cutter, a pinion journaled in the gripper in mesh with the rack, a hand lever connected with the pinion for turning the same to reciprocate the rack, and a lost-motion connection between the hand lever and the gripper for permitting the lever to be moved in one direction independently of the gripper to actuate the cutter, said lost-motion connection including a stop for limiting the movement of the lever relative to the gripper in the other direction, whereby movement of the lever in said othr direction will upon engagement with said stop return the gripper to its raised position.

2. A tool as defined by claim 1 characterized by said lost-motion connection and stop comprising an arcuate groove in said lever subtending an angle less than and a member projecting from said gripper into said groove and slidably engageable therewith.

3. A tool as defined by claim 2 characterized by said groove having a depression at one end and said projecting member being a yieldable spring-pressed pin having a conical tip adapted to fit in said depression.

4. In a strap-tensioning tool, a frame including a base and a wall upstanding thereon, a dog having a hub pivoted on said wall whereby the dog on downtilting will grip a strap end placed on said base, a locking pin reciprocable in said wall radially of said hub, said hub having a recess adapted to be entered by said pin when said dog is tilted upwardly to an inactive position, means constantly urging said pin toward said hub and means whereby said pin may be manually retracted.

r 5. A toolasdefined by claim 4 characterized by said last-mentioned means being a bell-crank pivoted on said wall and pivotally connected to said pin.

6. -A tool as defined by claim 5 characterized by said pin-urging means comprising spring means acting on said bell-crank.

References Cited in the fileofthis patent UNITED STATES PATENTS 8 Harvey May 20, 1930 Rietrnann et a1 aJune 14, 193.1 Harvey Feb. 14, 1933 Harvey Mar. 26, 1935 Watt et al July 26, 1938 Cox July 11, 1939 Spencer .Dec. 5, 1939 Gerrard May 7, 1940 Spencer May 19, 1942 Leslie Dec. 7, 1943 Cleveland Feb. 6, 1945

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