US3099055A

US3099055A - Strap tensioning device

Info

Publication number: US3099055A
Application number: US44801A
Authority: US
Inventors: Huber John Richard
Original assignee: Eastern Rotorcraft Corp
Current assignee: Eastern Rotorcraft Corp
Priority date: 1960-07-22
Filing date: 1960-07-22
Publication date: 1963-07-30
Anticipated expiration: 1980-07-30
Also published as: GB914085A; GB816968A

Description

July 30, 1963 J. R. HUBER STRAP TENsIoNNG DEVICE 2 Sheets-Sheet l Filed July 22. 1960 July .30, 1963 J. R. HUBER 3,099,055

STRAP TENsIoNING DEVICE Filed July 22, 1960 2 sheets-sheet 2 ATTNE Y United States Patent O 3,099,055 STRAP TENSIONING DEVICE Iiohn Richard Huber, Holicong, Pa., assignor to Eastern Rotorcraft Corporation, Doylestown, Pa., a corporation of Pennsylvania Filed July 22, 1960, Ser. No. 44,801 4 Claims. (Cl. 2.4-68) This invention relates to strap adjusting devices and is particularly concerned with devices of this nature in which tensioning mechanism is incorporated.

Strap adjusting devices of the type with which the present invention is concerned are often used for securing cargo in position and initial tensioning of the straps is particularly useful under these circumstances to securely retain the cargo in the loaded position. Inasmuch as the stra-p material is often nylon or similar stretchable webbing a considerable takeup is needed to apply the desired initial tension. With a section of strap several feet long the elongation 'will be several inches under a tension of say three hundred pounds. Strap devices previously used have incorporated a load transfer mechanism which includes a toggling movement designed to provide a slight initial takeup. Also previous devices for -adjusting the length of strap tension members have incorporated cams with a uni-directional action to permit pulling through the strap to a certain point and then providing a clamping force by means of the cam which holds the strap `at its adjusted position. With this latter type of engagement the maximum tension which can be attained in the adjusted strap is that which can be applied directly by hand when the strap is pulled through the device to adjusted position. With the toggling type of device the toggle is capable lof inducing tension in the strap but where the stretch is appreciable the amount of takeup is so small that it can produce a tension only slightly greater than that which can be applied by hand.

It is the primary object of the present invention to provide a strap adjusting and tensioning device which provides both a toggling mechanism and a cam clamping mechanism in proper related fashion so that the toggling mechanism can be operated repeatedly to produce the desired shortening or takeup eiect while the cam device may be used to provide a holding action to retain the takeup between successive movements of the toggling mechanism. By these repeated toggling movements any amount of stretch can be overcome and the full eiectiveness of the toggle may be developed so as to provide a strap tension several times the Value that can be applied directly :by hand.

In strap adjusting mechanism of this general nature the toggling mechanism may -be latched in the toggled position and is designed to transfer to the frame of the device the full load to be carried by the strap. This toggling portion of the mechanism is arranged to engage the strap in a manner which does not damage the strap under maximum load carrying conditions. On the other hand the camming action Ity-pe of strap holding mechanism normally will damage the strap if it is called upon to transfer the full load of which the strap is capable. The initial tension desired to be applied to the strap is usually only a fraction of the ultimate strength capacity of the load transfer device. Thus during the adjusting of the tension it is desired to hold only .the initial tension load by means of the camming device after which the load is picked up by the main holding mechanism. It is an important object of the invention therefore to provide the cam adjusting portion tof the mechanism so that after initial adjust ment has been made and the toggling device h-as been closed to the latched position for holdin-g the full capacity the cam mechanism is retained in a position where it is ineffective for load transfer. In this way the camming 3,099,055 Patented July 30, 1963 Fice mechanism cannot carry the high working loads of the device and thus damage to the strap is prevented.

In order to operate the device to obtain the initial tensioning it is desired to control the cam by the angle at which the unloaded end of the strap is held relative to the frame of the load transfer device. It is an object of the present invention to provide a construction yfor the cam element which permits it to engage the strap where it emerges from the device thus allowing the operator to control the takeup movement.

A fur-ther object of the invention is the provision of cam structure for retention of the strap to permit repeated takeup `of small increments of the strap which is compatible with the .general construction of existing strap clamping and load transfer devices.

How the lforegoing and other objects and advantages of the present invention are accomplished will be clear from the following description Iof the drawings in which- FIGURE l is a view showing the application of a strap device according to the present invention in holding down cargo during transport.

iFIGURE 2 is a sectional view of the load transfer device to an enlarged scale taken generally in the direction of arrows 2-2, FIGURE 3, showing the parts in closed, load carrying position.

FIGURE 3 is a view of the device taken in the direction of arrows 3 3, FIGURE 2.

FIGURE 4 is a view of a portion of the device shown in FIGURE 2 but with the parts in full open position of adjustment.

FIGURE 5 is a view similar to FIGURE 4 but showing the handle in a different position of adjustment.

FIGURE 6 is a sectional view taken in the direction of arrows 6-6, FIGURE 5.

Referring to the figures, FIGURE l illustrates a typical application for the securing device of the present invention. The door of the transporting vehicle is illustrated at 10 supporting a piece of cargo 11. 'Die down rings 12 `are attached to the vehicle structure and the strap 13 may he provided with a suitable anchor fitting 14 at one end. The strip 13 is attached to an adjusting and tensioning device 15 which, in the form illustrated, s rorided with a load transfer fitting in the form of a i oo The construction of the strap adjusting :and tensioning device `and the manner of operation will be clearly seen by reference to FIGURES 2 to 6. FIGURES 2 and 3 show the device with the strap and mechanism in the locked or load carrying position. The frame of the device 15 is shown `as a pair of spaced plates 16, the spac- 'ing being `suitable to accommodate the width of a strap and the adjusting mechanism. Near one end of the frame members 116 there is an anchor fitting in the form of hook 17. The load is transferred from the strap '13 to the frame 16 through the medium of strap engaging structure which may be moved to accommodate the adjustment of the strap to the proper length prior to anchoring the strap in the load transfer position. 'Ihis 4strap load transfer structure includes a beam member 18 which is supported in the frame 16 by a pin 19. Pin 19 also forms the pivotal support for a handle member 20 which incorporates two side plate members spaced to tit inside `the frame plates l16 and to accommodate the strap 13.

The pivoted end 21 of the handle 20 is enlarged and incorporates slots 22 which engage the pivot 19. Another `at its outer end. A slot 25 in each side of the handle accommodates a latch member 26 lwhich projects through the slots 25 in position to engage the notches 27 formed in the side frame members 16. A spring 28 reacts between the handle and the latch member 26 to urge the `latch 26 toward one end of the slots to `engage the notch 27. As will be evident the latch member 26 may be released against the spring force to disengage the notch 27 and permit the handle 20 to be moved for release or adjusting purposes.

Additional mechanism to assist in the tensioning of the strap is provided and this includes a cam member 29 having a cam portion 30 which .is supported between the frame plates 16 by means of a pivot pin 31. At the outer end of the extended `arm portion of the cam member 29 provision is made for engaging the strap such as by a slot 32. The cam portion 3910i the cam member is shaped so that when the cam member 29 is moved about its pivot 31 the cam portion will engage the strap 13 more intimately. To provide a clamping .action a transverse beam 33 is mounted in the frame plates `16 adjacent the cam portion 30 and thus forms a pressure surface to yaccomplish the clamping produced by the cam.

As shown in FIGURE 2 in the load carrying latched position of the device the loaded portion of the strap 13 enters the device from one end and passes between the pressure surface 33 and the cam portion 30, then extends around the beam v18 and over the outside of the beam 23. The strap end passes between the beam 23 and the beam 18 and around the beam 18 underneath the loaded portion of the strap. The unloaded end 13a of the `strap then passes outwardly to emerge from the device at the end of `the frame at which the loaded end entered. In proceeding from the anchoring beams 18 vand 23 the unloaded end 13a passes the frame spacer 34 which actually serves as a functional stop in a manner 'which will be described later. The unloaded portion `13a of the strap then extends past the cam member 29 n the side opposite the loaded portion `13 of the strap Iand passes Ithrough the slot 32. This arrangement posi- .tions the cam member 29 between the loaded and unloaded portions of the strap.

The manner in which the mechanism operates to adjust, tension and hold the load will be clear by reference to FIGURES 4 and 5. In FIGURE 4 the handle 20 is shown -in position for removing the slack from the strap and Iadjusting it to proper length for the condition under which it is being used. In the extreme open position of the handle the corner 35 engages the stop 34 `and by applying slight pressure on the handle in the direction of arrow 36 movement is permitted by the slots 22 to space the beam 23 away from the beam 118. Thus with the strap threaded through as shown and with the cam mechanism in the released position as shown by dotted outline the slack may be pulled freely through by a slight tension applied by hand to the unloaded Iend 13a of the strap. Since no appreciable load is in the strap it will move freely over the beam 23 While held in the posil tion shown in FIGURE 4.

When the slack has been removed and the tension retained by hand the handle may then be moved to the position shown by the dotted outline 20a in FIGURE 5. In this position the toe 35 has backed away from the stop 34 sufficiently to let the handle 20 move on the slots 22 so that the Ibeam 23 shifts toward the beam 18 and causes direct pressure to be applied to the strap =13 where it passes between the two

beams

23 and 18. At this position the clamping action between the 4beams will hold `an appreciable load on the loaded portion of strap 13. The handle movement may then be continued in the closing direction and the lengthening or toggling action which occurs -around the beams by virtue of this moveiment of the handle stretches the loaded portion 13 of the strap and induces initial tension. When the handle reaches the end of its stroke at say position 20b, FIG- URE .5J 111B Cam member 29 is moved .to clamped position by pulling at an `angle on the strap end 13a as shown in full line position ofthe cam member. This holds the tensioned strap in position at the surface 33 and allows the handle to be moved back to the position shown in FIGURE 4 while preventing the tension which Was obtained from being lost. By retaining the hand tightness on the strap end 13a the shortened requirement in the untoggled position FIGURE 4 permits the length difference to be pulled through and with the strap again hand tight between the clamping surface 33 and the unloaded end 13a the handle is again toggled from position 2i), FIGURE 4, to 20h, FIGURE 5.

The portion of the stroke between position Zita and Ztlb may be made with the cam relaxed from the surface 33 so that the toggling action yagain induces further tightening in the :stnap` 13. The relaxation of the cam during this portion of the `stroke is accomplished by moving the end 13a :of the strap to place the cam in the dotted position of FIGURE 4.

Repeated motion of the handle and manipulation of the end 13a of the strap to maintain the slight tension and change the `direction to apply and release the clamping action at the desired positions in the movement of the handle 2G permits incremental tightening action in the loaded end 13 of the strap. The maximum tension is determined by amount lof the load applied to the lend of the handle. With the particular mechanism illustrated a tension in the loaded strap 13 may be developed approximately t6 times the applied load at the handle. Thus for a handle load of 50 pounds a tension may be applied in the strap of 300 pounds by sequenti-al movements of the handle 20 while the end of strap 13a is manipulated to properly relate the operation 'of the holding cam device 33. When the desired tension has been applied the handle 20 is then moved all the way to the position shown in FIGURE 2. where the latch 26 engages in the fname notch 27 to retain the handle in closed position. In this position the cam member 29' lies approximately parallel to the handle and the cam action is in released position so that the loa-ded strap 13 is held by the

beam structure

18 and 23 which is designed to hold the strap without damage even at loads approaching the ultimate strength of the strap.

The portion of the mechanism illustrated for retaining and tnansferring the load from the strap to the frame is essentially the same as that shown in U.S. Patent 2,852,827. However other strap holding mechanism :of a generally similar nature could be used in combination with the camming device to provide tensioning and holding mechanism of the type involved.

From the foregoing it will be evident that I have provided an improved type of strap tensioning and anchoring device of the type which permits initial tensioning to an extent greater than can be attained by direct hand tensiom'ng. The strap holding mechanism of the toggling type wherein some takeup of the strap is attained during the handle closing movement combined with a holding clamp which is controllable in a fashion to phase its laction with the handle motion provides a simple mechanism for accomplishing the improved tensioning results. This mechanism has the advantage that it can handle any amount of takeup since the takeup is merely fed through to the unloaded end of the system. Therefore it is not limited by the capacity of a wind-up reel or the like such as would be the ycase with roll-up mechanism. The operation of the holding cam is simply and effectively accomplished by engaging the unloaded end of the strap in the structure of the cam member to control its operation merely by shifting the direction of hand applied tension at the strap. The particular relationship of the cam mem- .ber to the handle member assures that the cam is retained improved combination the basic structure of previously developed strap adjusting mechanism may be used to provide an improved device with increased tensioning capabilities.

I claim:

l. A strap adjusting `and tensioning device having a frame, an anchor fitting located at one end ot said fname, strap adjusting and load transfer mechanism attached to said trarne, said mechanism including a handle, a pivot attaching said handle to :said frame, a strap engaging beam mounted on said pivot and extending transversely with respect to said fname, 1a second strap engaging beam attached to said handle in offset relation to sm'd irst strap engaging beam, said handle being movable to a position closely adjacent said frame, a latch member interengag-ing said handle and said frame when the handle is in latched position, a strap clamping device movably mounted on said frame in la position offset from the pivotal mounting of said handle, and a strap including a rst portion extending into said frame at the end opposite said anchor iitting tand engaging both of said beams, said strap also including a second portion extending from said beams outwardly through the end of said frame at which said rst strap portion extends into said frame, said clamping device being located between said strap portions, said clamping ydevice incorporating a cam engageable with said rst strap portion and an extension ann engageable with said second `strap portion.

2. A strap adjusting land tensioning device according to claim l in which said clamping device is retained in non-clamping position when said handle is in latched position.

3. A strap adjusting and tensioning device having a frame, an I'anchor fitting located near one end of said frame, strap adjusting and load transfer structure attached to said frame, `a handle pivotally mounted on said frame, la plurality of transvense beams over which the strap may be wrapped for load transfer purposes, one of said beams being attached to said handle for movement therewith, a strap member engaging said device, said strap member having a load carrying portion entering said `frame from the end opposite said anchor fitting, then passing around said beams, an unloaded strap portion extending back adjacent said loaded portion, said handle being swingable about its pivotal mounting from -a generally uptight position with respect to said fname to a latched position where said handle is adjacent land parallel to said frame in a position overlying said portions of the str-ap located Within said frame, a cam device pivoted in said frame and lying below said handle and between the loaded and unloaded portions of said strap, and a transverse frame member forming a pressure surface adjacent said cam device, said load carrying portion of said strap passing between said cam device and said pressure surface, said cam device including a cam portion andan extension arm, said extension aim having engaging means for connecting to said unloaded portion of the strap to provide controlling means for operating the cam device.

4. A strap adjusting and tensioning device having a frame, an anchor fitting located at one end of said frame, strap adjusting `and load transfer mechanism attached to said frame, said mechanism including a handle pivotally mounted on said frame, a lstrap attachable to said device, structure comprising a plurality of beams around which ysaid strap passes to provide the load transfer means between said strap yand said frame, one of said beams being movably mounted relative to said handle to .puovide for relative movement of said beams from strap adjusting to str-ap loaded position, said strap having loaded `and unioaded portions located to entend from said frame at the end opposite `said anchor iitting, `a controllable strap clamping device lattached to said Iframe and positioned for clamping engagement with the loaded strap portion at ya location between the position of said beams and the end tof the frame from which said strap extends, said clamping device being positioned between .sa-id strap portions and including means engageable with said unloaded strap portion to provide for control movement of the clamping device.

References Cited in the file of this patent UNITED STATES PATENTS

Claims

1. A STRAP ADJUSTING AND TENSIONING DEVICE HAVING A FRAME, AN ANCHOR FITTING LOCATED AT ONE END OF SAID FRAME, STRAP ADJUSTING AND LOAD TRANSFER MECHANISM ATTACHED TO SAID FRAME, SAID MECHANISM INCLUDING A HANDLE, A PIVOT ATTACHING SAID HANDLE TO SAID FRAME, A STRAP ENGAGING BEAM MOUNTED ON SAID PIVOT AND EXTENDING TRANSVERSELY WITH RESPECT TO SAID FRAME, A SECOND STRAP ENGAGING BEAM ATTACHED TO SAID HANDLE IN OFFSET RELATION TO SAID FIRST STRAP ENGAGING BEAM, SAID HANDLE BEING MOVABLE TO A POSITION CLOSELY ADJACENT SAID FRAME, A LATCH MEMBER INTERENGAGING SAID HANDLE AND SAID FRAME WHEN THE HANDLE IS IN LATCHED POSITION, A STRAP CLAMPING DEVICE MOVABLY MOUNTED ON SAID FRAME IN A POSITION OFFSET FROM THE PIVOTAL MOUNTING OF SAID HANDLE, AND A STRAP INCLUDING A FIRST PORTION EXTENDING INTO SAID FRAME AT THE END OPPOSITE SAID ANCHOR FITTING AND ENGAGING BOTH OF SAID BEAMS, SAID STRAP ALSO INCLUDING A SECOND PORTION EXTENDING FROM SAID BEAMS OUTWARDLY THROUGH THE END OF SAID FRAME AT WHICH SAID FIRST STRAP PORTION EXTENDS INTO SAID FRAME, SAID CLAMPING DEVICE BEING LOCATED BETWEEN SAID STRAP PORTIONS, SAID CLAMPING DEVICE INCORPORATING A CAM ENGAGEABLE WITH SAID FIRST STRAP PORTION AND AN EXTENSION ARM ENGAGEABLE WITH SAID SECOND STRAP PORTION.