US3189060A

US3189060A - Strap tensioning tool

Info

Publication number: US3189060A
Application number: US185775A
Authority: US
Inventors: Attas Jack Eli
Original assignee: FMC Corp
Current assignee: CYKLOP STRAPPING Corp A CORP OF
Priority date: 1962-04-03
Filing date: 1962-04-03
Publication date: 1965-06-15
Anticipated expiration: 1982-06-15

Description

June l5, 1965 J. E. ATTAs STRAP TENsIoNING TooL 2 Sheets-Sheetv l Filed Apr'.. 5, 1962 Fig- 3 J. E. ATTAS STRAP TENSIONING TOOL June 15, 1965 2 Sheets-Sheet 2 Filed April 5. 1962 United States Patent O nlidl STRAP TENSNHNG TL .lach Eli Attas, Westmount, Quebec, Canada, assigner, by mesne assignments, to FMC Corporation, San Jose, tlalif., a corporation of Uelaware Filed Apr. 3, i962, Ser. No. 85,775 7 Claims. (Cl. Mil- 123) This invention relates to strapping tools of the type used for tensioning or stretching straps or bands about shipping carto-ns and the like.

Cartons, bundles, packages and groups of articles to be shipped in commerce are frequently provided with reinforcing straps which extend tightly thereabout with the ends thereof held in overlapping relation by means of a suitable clamp. When all articles being strapped are of the same size, strapping material precut to length is often used and when strapping articles of varying sizes, it is customary to withdraw the needed length of strapping from a supply such as a roll and tension and secure it about the article before cutting the secured portion from the supply. In either event, the tensioning operation is generally performed with the aid of a tool which has means for holding one end of the strapping material stationary and means for engaging another portion of the strapping Ito draw it tight about the article in overlapping relation with the held end whereby the overlapping portions may be engaged by a clamp or seal to hold the strapping tight. Such tools are generally known as tensioning tools or stretching tools and it is toward the improvement of such tools that the present invention is directed.

lt is an object of this invention to provide a strap tensioning tool having an improved arrangement for holding one end of a length of strapping material stationary while the strapping is drawn tight about an article in overlapping relationship with the held end.

It is a more specic object of the invention Ito provide a strap tensioning tool, of the type having a windlass about which the strap is wound to draw it tight, with a means which operates in conjunction with the windlass to increase the grip on the stationary end of the strap as the strap is drawn tighter by the windlass.

A. further object of the invention is to provide a strap tensioning tool of the windlass type wherein the windlass is operated by power and having a strap end gripping device which is released from the strap by operation of a lever which is also effective to discontinue the application of power to the Windlass.

Another object of the invention is to provide a strap tensioning tool having gripping means for holding an end of strapping material, a power driven windlass for drawing the strapping material tight about an object and a cutter for cutting the bound strap from the supply of strapping with a single operating lever effective to operate the cutter, discontinue the application of power to the windlass and release the gripping means.

Other objects, features and advantages of the invention wiil become apparent as the description of a preferred embodiment thereof proceeds.

Referring now to the drawings:

FIG. l is a front elevational view of the tool showing the same in use;

FIG. 2 is a side elevational view of the tool;

FG. 3 is a plan view of the front portion of the tool, part of the operating handle being broken away for clarity of illustration;

FlG. 4 is a `front elevational View showing the strap end gripping means released and the cutter operated; and

FlG. 5 is an exploded View showing the construction of the strap end gripping means.

Patented June l5, i965 "ice In general the tool of the present invention is similar to that described in the application of M. O. Derrickson, Serial No. 152,590, tiled November l5, 1961, now Patent No. 3,006,706 and includes a more or less cylindrical handle portion l@ within which is mounted a motor, preferably an air motor, operatively arranged to drive a strap tensioning means in the form of a slotted windlass lll which protrudes from the front end of the tool. The motor is driven from a source of compresssed air which is connected to the rear end of the handle portion through a coupling l2. A valve for controlling the ilow of air to the motor has a stem i3 which extends outwardly from the side of handle portion lil and said stem is provided with a finger piece 14 by means of which it may be pushed into the handle portion against the action of a spring to thereby admit compressed air to the motor and cause the same to drive windlass ll as explained in the above mentioned Derrickson application. An operating lever in the form of a bail l5 having legs 16 and ll7vis pivotably mounted on the main body of the tool, the pivot for the leg lo being indicated in FIG. 2 at 31S. Extending outwardly from lthe lower end of leg 17 is a tab .t9 provided with a cam slot 20, see FlG. 4, within which is engaged a pin 2l secured to an arm 22 of a cutter shaft 23. Cutter shaft 23 is rockably mounted in a member Z4 secured to the lower portion of a housing member 25 which is iixed to the forward end of cylindrical handle portion lil. Member 24 is provided with a strap-guiding slot 25 through which the strap is pulled lduring the tensioning operation, as will presently be explained. Cutter shaft 23 is cylindrical except where it passes through guide slot 25' and in that area it has a iiat :sunface 26 best seen in FIG. 4. The strap, in passing through slot 25, lies beneath the flat surface Z6 and when the cutter shaft is rocked from the position shown in FIG. l to the position shown in FIG. 4, an edge of fiat surface 2d in cooperation with an edge 27 of slot 25 cuts the strap.

A coil spring 28 extends around cutter shaft 23 between arm 22 and a collar 29 secured to or formed integrally with member 24. Spring 28 is secured at one end to arm 22 and at the other end to collar 29 and, through pin and slot connection Ztl and 2l, urges leg lo of bail lever i5 against the side of the valve stem i3 as shown in FIG. 3. With leg lo resting against valve stern 13, the cutter member is positioned as shown in FIG. l so that the strap may be passed freely through guide slot 25 and beneath the flat surface 26 of the cutter member. Valve stem 13 is provided with a notch 3) and when said valve stein is pushed in to activate the motor of the tool, spring 28 moves leg .t6 into said notch to thereby hold the valve stem in and continue the motor in operation. This slight movement of leg t6 and the accompanying movement of the cutter shaft is insuflicient to appreciably change the location of dat surface 26 of the cutter and does not result in cutting the strap. When bail lever l5 is moved rearwardly from the full-line position shown in FlG. 2 to the dotted-line position, the engagement of pin 2l within slot 2i) causes the cutter shaft to rock from the FlG. l position to the FIG. 4 position to thereby cut the tape and this rearward movement'of the bail lever also frees the leg 16 from notch 30 of the valve stem whereupon the valve stem is moved out by its spring to shut otf the motor, as explained in the aforementioned Derriclrson application.

Secured to the housing member 25 on the side opposite member 24 is a bracket 3l, the construction of which is best shown in FlG. 5, which includes a 'toot portion 32 located in alignment with the bottom of said housing member. A link 33 is pivotably mounted upon a shaft 3d (see PIG. 4) extending between a pair of side plates E and 36 of the bracket 31 and at its lower end said link has rockably mounted therein a pin 37 rotatably mounted upon which is a drum 38 having a concave surface. Loosely mounted on pin 37 by means of a pair of ears 40 and 41 which lie adjacent the sides of lever 33 is a gripper member indicated generally at 42 having a foot portion 43 which extends parallel to the upper surface of foot portion 32 of bracket 31. As indicated at 44 in FIG. 4, the bottom surface of foot portion 43 is serrated. When the parts are assembled, ear 40 is aligned with side plate 35 of bracket 31 and ear 41 lies adjacent the inner surface of side plate 36 of said bracket.

Side plate 36 is provided with a pair of downwardly

sloping slots

45 and 46. Pin 37 is engaged in slot 45 and a pin 47 extending from gripper member 42 rides in the slot 46. Link 33 and ears 40 and 41 constitute a toggle joint which when bent at the knee raises foot portion 43 away from foot portion 32, as shown in FIG. 4. The engagement of

pins

37 and 47 within

slots

45 and 46 causes the serrated bottom surface of foot portion 43 to remain parallel to the upper surface of foot portion 32 at all times so that as the toggle joint is straightened the entire bottom surface tof foot portion 43 engages the strap at one time to thus avoid possible damage to the strap which might be caused by foot portion 43 engaging it at an angle. A coil spring 48, shown in FIGS. 2 and 3, surrounds shaft 34 and is anchored at one end to link 33 and at the other to the side plate 36 of bracket 31. Spring 48 urges foot portion 43 toward foot portion 32 and normally holds them in light engagement. Together, foot 32 and gripper member 42 constitute a strap end holding means.

Extending outward from the lower end of bail lever leg 16 is a curved tab 49 having a sloping cam surface Sil interconnecting two substantially vertical surfaces 51 and 52. When bail lever 15 is in normal position, that is with leg 16 bearing against the cylindrical surface of valve stem 13, the upper vertical surface 51 of tab 49 is aligned but tout of contact with a roller 53 mounted on toggle joint shaft 37 and this relative position of surface 51 and roller 53 also prevails when leg 16 is located within the notch 30 of the valve stern, that is, when the motor is in operation. Thus, unless the serrated surface 44 of foot portion 43 is actually in contact with foot portion 32, shaft 37 is free to move toward the main body of the tool to more nearly straighten the toggle joint comprising link 33 and ears 40 and 41. Upon movement of bail lever 15 from the full-line position shown in FIG. 2 to the dotted-line position, sloping cam surface contacts roller 53 to bend the toggle joint as shown in FlG. 4 to thereby D raise foot portion 43 out of contact with foot portion 32.

With lever 15 in the rearmost position, roller 53 is just at the edge of cam surface 50 and does not move onto vertical surface 52. Therefore, upon release of lever 15, spring 48 is effective to restore said lever and gripper member 42 to the positions shown in FlGS. 1, 2, and 3.

In use, the tool may be placed upon a horizontal surface of the article to be strapped, such as box 55 shown in FIG. l. A length of strapping material 56 is then withdrawn from a supply and led about the box. The operator depresses or moves rearward the bail handle 15 thereby raising gripper member 42 out of contact with foot portion 32 and inserts the leading end portion of the strap between the foot portion 43 of the gripper member and the foot portion 32 in such manner that the extreme end of the strap extends forward oi' member 24, that portion of the strap between the extreme end and the gripper lying beneath member 24 as shown. The bail handle is Ithen released so that the strap is pinched lightly between the

foot portions

32 and 43. The trailing portion of the strap is then inserted into guide slot 25 of member 24 and a portion of the strap is directed about roller 38 and engaged with the tensioning means or windlass 11 as shown in FIG. l. Valve stem 13 is then pushed in by means of the finger piece 14 to start the motor as aforesaid to cause windlass 11 to rotate in a counterclockwise direction. As the strap is wound about the windlass to draw it tight about the package, it exerts a force on roller 38 toward the left as viewed in FIG. 1 and this force tends to straighten the toggle joint comprised of crank 33 and ears 4t? and 41 of the gripper element 42 to thereby increase the pressure of foot portion 43 against the strap. Thus, the greater the tension applied to the strap by windlass 11, the greater the restraining force applied against the free end of the strap. As explained in the above referred to Derrickson application, when the strap reaches a preselected tension, the motor stalls and rotation of the windlass ceases but the windlass continues to maintain the tension on the strap. The overlapping portions of the strap are then secured together forwardly of member 24 as by applying a suitable seal thereabout in a well-known manner. With the strap thus secured tightly about the package, the operator again moves bail handle 15 rearwardly to thereby operate cutter 23, release valve stem 13, so as to disconnect the motor, and raise the gripper member 42, all as hereinabove described.

Because of the rather sharp bend of the strap as it passes about roller 38, the tool of the present invention is primarily intended to use with a strap having a higher degree of flexibility than steel strapping and it is contemplated that its greatest utility will be found in connection with the heavy-duty weftless cord straps currently coming into vogue.

Having thus described the invention and pointed out the utility thereof, what is claimed is:

1. A strap tensioning tool comprising tensioning means for engaging a trailing portion of a strap and drawing it tight about a package in overlapping relationship with the leading end of the strap, strap end holding means for holding the leading end of the strap stationary while the strap is drawn tight by the tensioning means, said holding means comprising a relatively stationary member for engaging one face of the strap and a relatively movable member for engaging the other face of the strap so as to squeeze the strap therebetween, said members having parallel strap engaging surfaces, means for maintaining parallelism between said surfaces in all relative positions of said members, spring means urging said relatively movable member toward said relatively stationary member, means for moving said relatively movable member away from said relatively stationary member, and means connected to said relatively movable member adapted to be engaged by the strap between said end holding means and said tensioning means to move said movable member toward said relatively stationary member as the strap is drawn tight by the tensioning means whereby the squeezing force of said end holding means is increased as the strap is drawn tighter.

2. A strap tensioning tool comprising a windlass for engaging a trailing portion of a strap and drawing it tight about a package in overlapping relationship with the leading end of the strap, control means movable to a iirst position to connect said windlass to power source and spring urged to a second position wherein the windlass is disconnected from the power source, strap gripping means for holding the leading end of the strap stationary while the strap is drawn tight by said windless, means associated with said strap gripping means adapted to be engaged by the strap between said gripping means and said windlass to increase the gripping action of said gripping means as the strap is drawn tight, a swingably mounted lever movable in a irst direction to hold said control mean in its said irst position and in a second direction to permit said control means to move to its said second position, and means operatively connecting said lever .to said strap gripping means whereby movement of said lever in its said second direction is effective to release said gripping means from enga gement with the strap.

3. A strap tensioning tool comprising a windlass for engaging a trailing portion of a strap and drawing it tight about a package in overlapping relationship with the leading end ot the strap, control means movable to a rst position to connect said windlass to a power source and spring urged to a second position wherein the windlass is disconnected from the power source, strap end holding means for holding the leading end of the strap stationary while the strap is drawn tight by said windlass, said holding means comprising a relatively stationary member for engaging one face of the strap and a relatively movable member for engaging the other face or" tho strap so as to squeeze the strap therebetween, means associated with Said relatively movable member adapted to be engaged by the strap between said end holding means and said windlass to move said movable member toward said relatively stationary member as the strap is drawn tight whereby the squeezing force of said end holding means is increased as the strap is drawn tighter, a swingably mounted lever movable in a rst direction to hold said control means in its said rst position and in a second direction to permit said control means to move to its said second position, and means operatively connecting said lever to the relatively movable member of said strap end holding means whereby movement of said lever in its said second direction is effective to move said relatively movable member away from said relatively stationary member.

d. A strap tensioning tool comprising a windless for engaging a trailing portion of a strap and drawing it tight about a package in overlapping relationship with the leading end of the strap, control means movable to a first position to connect said windlass to a power source and spring urged to a second position wherein the Windlass is disconnected from the power source, strap end holding means for holding the leading end of the strap stationary while the strap is drawn tight by said windlass, said holding means comprising a relatively stationary member for engaging one face of the strap and a relatively movable member for engaging the other face of the strap so as to squeeze the strap therebetween, said members having parallel strap engaging surfaces, means for maintaining parallelism between said surfaces in all relative positions of said members, spring means urging said relatively movable member toward said relatively stationary member, means associated with said relatively movable member adapted to be engaged by the strap between said end holding means and said windlass to move said movable member toward said relatively stationary member as the strap is drawn tight whereby the squeezing force of said end holding means is increased as the strap is drawn tighter, a swingably mounted lever movable in a iirst direction to hold said control means in its said irst position and in a second direction to permit said control means to move to its said second position, and means operatively connecting said lever to relatively movable member of said strap end holding means whereby movement of said lever in its said second direction is effective to move said relatively movable member away from said relatively stationary member.

5. A strap tensioning tool comprising tensioning means for engaging a trailing portion of a strap and drawing it tight about a package in overlapping relationship with the leading end of the strap, strap end holding means for holding the leading end of the strap stationary while the strap is drawn tight by the tensioning means, said holding means comprising a relatively stationary member for engaging one face or the strap and a relatively movable member for engaging the other face of the strap so as to squeeze the strap therebetween, a link pivotally mounted at one end on a stationary pivot, a pin pivotally connecting the other end of said link to said relatively movable member, said link and said relatively movable member constituting a toggle joint, means associated with the toggle joint adapted to be engaged by the strap between the strap end holding means and the tensioning means whereby increasing tension on the strap tends to straighten said toggle joint and cause the relatively movable member to move toward the relatively stationary member whereby the squeezing *force of said end holding means is increased as the strap is drawn tighter, and means for moving said pin to break the toggle joint and release the strap.

6. A strap tensioning tool comprising tensioning means or engaging a trailing portion of a strap and drawing it about a package in overlapping relationship with the -ading end of the strap, strap end holding means for olding the leading end of the strap stationary while the strap is drawn tight by the tensioning means, said holding :leans comprising a relatively stationary member for enone face of the strap and a relatively movable member for engaging the other face of the strap so las to squeeze the strap therebetween, said members having parallel strap engaging surfaces, means for maintaining parallelism between said surfaces in all relative positions oi said members, a link pivotally mounted at one end on a stationary pivot, a pin pivotally connecting the other end ot said link to said relatively movable member, said link and said relatively movable member constituting a toggle joint, means on said pin adapted to be engaged by the strap between the strap end holding means and the tensioning means whereby increasing tension on the strap tends to straighten said toggle joint and cause the strap engaging surface of said relatively movable member to move toward the strap engaging surface of said relatively stationary member whereby the squeezing force of said end holding means is increased as the strap is drawn tighter, and means for moving said pin to bneak the toggle joint and release the strap.

'7. A strap tensioning tool comprising a windlass for engaging a trailing portion of a strap and drawing it tight about a package in overlapping relationship with the leading end of the strap, control means movable to a first position to connect said windlass to a power source and spring urged to a second position wherein the windlass is disconnected from the power source, strap end holding means for holding the leading end of the strap stationary while the strap is drawn tight by the tensioning means, said holding means comprising a relatively stationary member for engaging one face of the strap and a relatively movable member for engaging the other face of the strap so as to squeeze the strap therebetween, said members having parallel strap engaging surfaces, means for maintaining parallelism between said surfaces in all relative positions of said members, a link pivotally mounted at one end on a stationary pivot, a pin pivotally connecting the other end oi said link to said relatively movable member, said link and said relatively movable member constituting a toggle joint, means on said pin adapted to be engaged by the strap between the strap end holding means and the tensioning means whereby increasing tension on the strap tends to straighten said toggle joint and cause the strap engaging surface of said relatively movable member to move toward the strap engaging surface of said relatively stationary member whereby the squeezing torce of said end holding means is increased as the strap is drawn tighter, a swingable mounted lever movable in a iirst direction to hold said control means in its said irst position and in a second direction to permit said control means to move to its second position, said lever being ellective when moved in its second direction to engage said pin and break the toggle whereby the strap is `released from said end holding means.

References Cited by the Examiner UNITED STATES PATENTS 1,963,593 6/34 Prindle 14C-93.4 2,580,848 l/52 Schulze 140-93 2,779,356 1/57 Schulze 140-93 3,048,204 8/62 Lingle P10-123.6 3,066,706 12/62 Derrickson 140-123.6

CHARLES W. LANHAM, Primary Examiner.

RICHARD A. WAHL, Examiner.

Claims

1. A STRAP TENSIONING TOOL COMPRISING TENSIONING MEANS FOR ENGAGING A TRAILING PORTION OF A STRAP AND DRAWING IT TIGHT ABOUT A PACKAGE IN OVERLAPPING RELATIONSHIP WITH THE LEADING END OF THE STRAP, STRAP END HOLDING MEANS FOR HOLDING THE LEADING END OF THE STRAP STATIONARY WHILE THE STRAP IS DRAWN TIGHT BY THE TENSIONING MEANS, SAID HOLDING MEANS COMPRISING A RELATIVELY STATIONARY MEMBER FOR ENGAGING ONE FACE OF THE STRAP AND A RELATIVELY MOVABLE MEMBER FOR ENGAGING THE OTHER FACE OF THE STAP SO AS TO SQUEEZE THE STAP THEREBETWEEN, SAID MEMBERS HAVING PARALLEL STRAP ENGAGING SURFACES, MEANS FOR MAINTAINING PARALLELISM BETWEEN SAID SURFACES IN ALL RELATIVE POSITIONS OF SAID MEMBERS, SPRING MEANS URGING SAID RELATIVELY MOVABLE MEMBER TOWARD SAID RELATIVELY STATIONARY MEMBER, MEANS FOR MOVING SAID RELATIVELY MOVABLE MEMBERS AWAY