US3726507A

US3726507A - Load binder

Info

Publication number: US3726507A
Application number: US00151732A
Authority: US
Inventors: M Rymsza
Original assignee: MacLean Fogg Lock Nut Co
Current assignee: Holland Co; MacLean Fogg Lock Nut Co
Priority date: 1971-06-10
Filing date: 1971-06-10
Publication date: 1973-04-10
Anticipated expiration: 1990-04-10
Also published as: AU4171772A; JPS501200B1; ZA722577B; DE2220550A1; DE2220550B2; CA938838A; FR2140392A1; IT958562B; AU474338B2; DE2220550C3; GB1335362A; ES402416A1

Abstract

A variable advantage force applying device is disclosed as applied to a load binder used to tighten a flexible fastener such as a rope, cable or chain around a load to hold the load against shifting on the bed of a carrier or to fasten a bundle of heavy objects together. The device uses a lever pivoted to one end of the flexible fastener and connected to the other end of the fastener by a pin and slot. The slot is curved and disposed to move the pin toward the pivot for the lever as the lever is swung in a tightening direction. As the pin moves closer to the pivot, it increases the mechanical advantage of the lever at the stage of the tightening operation during which the resistance to tightening increases. An overcenter arrangement is incorporated in the pin and slot according to accepted design practice to hold the fastener in a tightened condition.

Description

United States Patent [191 Rymsza [451 Apr. 10, 1973 LOAD BINDER [73] Assignee: MacLean-Fogg Lock Nut Co., Mundelein, Ill.

[22] Filed: June 10, 1971 [21] Appl.No.: 151,732

2,422,001 6/ l 947 Durbin ..254/78 Primary Examiner--Othell M. Simpson Assistant Examiner-Robert C. Watson Attomey-Davis, Lucas, Brewer & Brugman [57] ABSTRACT A variable advantage force applying device is disclosed as applied to a load binder used to tighten a flexible fastener such as a rope, cable or chain around a load to hold the load against shifting on the bed of a carrier or to fasten a bundle of heavy objects together. The device uses a lever pivoted to one end of the flexible fastener and connected to the other end of the fastener by a pin and slot. The slot is curved and disposed to move the pin toward the pivot for the lever as the lever is swung in a tightening direction. As the pin moves closer to the pivot, it increases the mechanical advantage of the lever at the stage of the tightening operation during which the resistance to tightening increases. An overcenter arrangement is incorporated in the pin and slot according to accepted design practice to hold the fastener in a tightened condition. I I

6 Claims, 7 Drawing Figures LOAD BINDER This invention relates to tightening devices for flexible fasteners such as ropes, cables, chains or the like and will be described for illustrative purposes as applied to load binders used to tighten a flexible fastener about a load on a carrier to keep the load from shifting.

Load binders as presently commercially available comprise a lever provided with two pivots at one end, one pivot being connected to one end of the flexible fastener and the other pivot being connected to the other end of the fastener or to an anchor on the carrier. The two pivots are so related that as the load is tightened they pass one another and then pass over the line of thrust, i.e., over center to lock in the tightened position.

The load binders are tightened manually, and, obviously, the effort required to bring them to the locked, over-center position increases as that position is approached. To reduce the physical exertion required, the operator may increase the mechanical advantage of the lever by providing a makeshift extension of the lever in the form of a pipe slipped over the end of the lever and extending beyond the lever to lengthen it. This renders the operator somewhat insensitive to the maximum allowable load for the binder, to the detriment of the binder, of the load being made secure and of the rope, chain or cable used as the fastening means.

It is a broad object of this invention to provide a load binder which reduces the maximum exertion required of its operator at the end-point of the load binding operation as compared with the maximum exertion required by presently commercially available load binders.

A more specific object of this invention is the provision of a load binder which incorporates a variable mechanical advantage device as one of the the connections between the binder and the flexible fastening means, the device being arranged to increase the mechanical advantage of the manually operated lever of the binder as the binder approaches its maximum tightness, thereby reducing the effort put forth at that point over the effort previously required.

As a still more specific object, this invention has within its purview the provision of a simple and inexpensive pin-and-slot form of connection between the lever of a load binder and the fastening means to be tightened by it, said connection being so disposed as to function as a device for varying the mechanical advantage of the lever as the binder tightens the fastening means.

These and other objects of the invention will become apparent from the following detailed description of a preferred embodiment thereof when taken together with the accompanying drawings in which:

FIG. 1 is a plan view of the load binder of this invention shown in its extended or unloaded condition;

FIG. 2 is a rear elevational view of a portion of the load binder of FIG. 1 looking in the direction of the line 2-2 of FIG. 1;

FIG. 3 is a front elevational view of the load binder of FIG. 1; and

FIGS. 4, 5, 6 and 7 are fragmentary plan views of the mechanical advantage changing device forming part of the invention, the device being shown in various stages of operation.

The load binder of this invention differs from prior load binders in that one of the connections between the manually operated lever and the flexible fastener passing around the load is a pin-and-slot connection rather than a fixed pivot, the slot being curved so that as the lever is turned about its fixed pivot the pin moves in the slot inwardly toward the fixed pivot, thereby changing the effective moment arm to shorten it and thus create a progressively greater mechanical advantage for the lever which reaches a maximum just as the load binder passes dead center into a locking position.

Referring now to the drawings for a detailed description of the invention depicted therein, the binder as shown in FIG. 1 is comprised of a lever 10 having an end 11 which functions as a handle to be grasped by the operator, and having a fixed pivot 12 near its other end. A link 13 is connected to pivot 12 for free movement therearound, said link 13 being connected by a flexible connection such as another link 14 to a hook 15 adapted to engage one end 16 of a flexible tie element or fastener 17 such as a chain, cable or rope passing around a load (not shown). The other end of flexible fastener 17 is shown at 18 engaging a hook 19 which may be similar to or identical with hook 15. The general objective of the load binder is to draw hooks 15 and 19 toward one another to tighten the fastener 17 around the load. Alternatively

links

16 and 18 may be portions of separate fastening means the other ends of which are connected to anchors on the bed or wall of a carrier such as atruck, plane or freight car.

The means by which the hooks 15 and 19 are drawn toward one another comprise a flexible connection 20 similar to flexible connection 14, said connection 20 connecting hook 19 to a link 21, the free end of which is provided with a pin 22 appropriately retained within a curved slot 23 formed in that end of lever 10 which extends beyond fixed pivot 12. As shown more clearly in FIGS. 2 and 3, link 13 may be a clevis which straddles lever 10. Link 21 is in the form of a tongue which passes into a longitudinal groove 24 formed in the end of lever 10 and intersecting slot 23, said slot 23 extending on both sides of groove 24 and providing spaced bearing surfaces for pin 22.

It may be noted that slot 23 is curved and extends in a general radial direction with respect to fixed pivot 12. The line of thrust between hooks l5 and 19 passes through a plane which is perpendicular to the plane of FIG. 3 and is symmetrically disposed with respect to the sides of clevis l3 and tongue 21.

To tighten fastener 17 around a load, handle 11 is swung clockwise as shown in FIGS. 4-7 about pivot 12 through somewhat less than from a position in which lever 10 abuts the top of the clevis 13 to a position wherein lever 10 is substantially parallel to and below tongue 21. The tightened position is shown in FIG. 7 and the intermediate stages are shown in FIGS. 4, 5 and 6. It may be noted in FIG. 4 that the effective moment arm for the binder is the longest when the elements of the binder bear the relation to one another depicted in that FIG. The moment arm is shown by the arrow 26. When the moment arm is the longest, the mechanical advantage of course is the least. It may be noted further in FIG. 4 that lever 10 has been swung through approximately 45 from the relaxed position shown in FIG. 1 and because of the curvature of slot 23, pin 22 has slid a short distance from its end position.

In FIG. 5, lever 10 has been swung approximately another 5 to degrees and again, due to the curvature of slot 23, pin 22 has slid approximately through the mid point in slot 23. This has still further shortened the effective moment arm as shown by the arrow 27.

In FIG. 6, the lever 10 has been rotated approximately 80 from its initial position, which brings pin 22 to the inner end of slot 23. At this point the moment arm is the shortest and is shown at 28.

In FIG. 7 lever 10 has been swung as far as it is possible in a clockwise direction, and in the process, the line of thrust between hooks and 19 has passed through fixed pivot 12 and the binder now is in an over-center position which locks lever 10 in its left-hand position as shown in FIG. 7.

.Thus with the variable mechanical advantage device of this invention, that is, the pin-and-slot connection between lever 10 and link 21, the force required to be exerted by the operator on lever 10 is reduced as the fastener is tightened as compared with the force that would be required were a fixed pivot used in place of the pin-an'd-slot connection as is commonly done in the prior art load binders. This decreased force makes the load binder easier to operate and hence reduces or eliminates entirely the need for the use of extensions on handle 11 such as the types previously resorted to by load binder operators. The pin-and-slot connection is relatively inexpensive to make, it is sturdy and requires no additional or new procedure for the operation of the binder. v

. The curved slot provides stability to the binder as the lever 10 is swung for either tightening or loosening the binding force. Pin 22 always seeks the position in the slot at which a tangent to the concave curvature of the surface of the slot is at right angles to the line of thrust through the pin. The movement of pin 22 is automatic in response to the change in the location of the line of thrust.

Other forms of connections may be used in place of the pin-and-slot connection illustrated herein. For example, a roller or slide may be used in place of pin 22 and slot 23 may be replaced by a concave cam surface. It is understood therefore that the foregoing description is merely illustrative of a preferred embodiment of this invention and that the scope of the invention is not to be limited thereto but is to be determined by the appended claims.

I claim:

l. A load binder of the type adapted to develop and exert tensile force between opposed first and second flexible tie elements and comprising, in combination, a lever having long and short arm portions extending away from opposed sides of a first pivot element which serves as a fulcrum for swinging movements of the lever, the long arm portion of the lever serving as a handle through which operating force is applied thereto, said short arm portion having a curved cam slot therein which extends in a direction which is generally radial to the first pivot element and has a concave cam surface provided by a longitudinal side wall of the cam slot, saidfirst flexible tie element being connected to said first pivot element, a second pivot element mounted in said cam slot and movable therealong from end to end thereof while engaged with said concave cam surface, said second flexible tie element being connected to said second pivot element and extending therefrom in a direction to urge said second pivot element toward said concave cam surface, said lever having a normal loose tie position in which the long arm portion thereof extends along one flexible tie element and a tightened tie position in which the long arm portion thereof extends along the other flexible tie element, said pivot elements being movable toward and from one another in stable increments which are dependent upon the position of said lever during swinging movements thereof about said first pivot to provide gradual changes of mechanical advantage as the lever moves between said loose and tightened tie positions, the curvature and disposition of the cam slot being such that a major portion of said cam slot crosses the line of thrust between the tie elements and thereby causes the line of thrust to intersect said first pivotelement during the swinging movement of the lever to and from the tightened tie position, and means for limiting movement of said lever after said major portion of the cam slot has crossed the line of thrust in moving toward the tightened tie position of the lever.

2. A load binder as defined in claim 1, and wherein said concave cam surface is arcuate.

3. A load binder as defined in claim 1, and wherein said second pivot element moves toward the first pivot element during an intermediate portion of swinging movement of the lever between the loose tie position and the tightened tie position to provide a gradual increase of the mechanical advantage of the lever during said intermediate portion of the swinging movement thereof.

4. A load binder mechanism of the type adapted to develop and exert tensile force along a line of thrust extending between two tie elements and comprising, in combination, a unitary lever having long and short arm portions on opposed sides of a fixed pivot element which serves as a fulcrum for swinging movement of said lever by which the operation of the mechanism is effected, said long arm portion of the lever serving as a handle for applying force thereto, said short arm portion having a curved cam slot therein, one end of which curved cam slot is near said fixed pivot element, and which cam slot extends away from the fixed pivot element and has a second pivot element mounted therein for movements along the cam slot toward and from the fixed pivot element as the lever is swung around the fixed pivot element, one of said tie elements being connected to the fixed pivot element and extending therefrom in one direction of thrust, the other of said tie elements being connected to the movable second pivot element and extending in a direction of thrust opposed to that aforementioned, said curved cam slot having a concavely curved cam surface against which the movable second pivot element is held in contact by the thrust applied thereto during swinging movements of said lever, said lever having loose and tightened positions in which the handle extends in generally opposite directions from the fixed pivot element, and the curvature of said cam surface being sufficient to restrain the movements of the movable second pivot element along the cam surface in relation to the angular swinging pivot element.

6. A load binder mechanism as defined in claim 4, and wherein the movable second pivot element crosses the line of thrust extending between the two tie elements at a position of said lever close to the said tightened position thereof.

Claims

1. A load binder of the type adapted to develop and exert tensile force between opposed first and second flexible tie elements and comprising, in combination, a lever having long and short arm portions extending away from opposed sides of a first pivot element which serves as a fulcrum for swinging movements of the lever, the long arm portion of the lever serving as a handle through which operating force is applied thereto, said short arm portion having a curved cam slot therein which extends in a direction which is generally radial to the first pivot element and has a concave cam surface provided by a longitudinal side wall of the cam slot, said first flexible tie element being connected to said first pivot element, a second pivot element mounted in said cam slot and movable therealong from end to end thereof while engaged with said concave cam surface, said second flexible tie element being connected to said second pivot element and extending therefrom in a direction to urge said second pivot element toward said concave cam surface, said lever having a normal loose tie position in which the long arm portion thereof extends along one flexible tie element and a tightened tie position in which the long arm portion thereof extends along the other flexible tie element, said pivot elements being movable toward and from one another in stable increments which are dependent upon the position of said lever during swinging movements thereof about said first pivot to provide gradual changEs of mechanical advantage as the lever moves between said loose and tightened tie positions, the curvature and disposition of the cam slot being such that a major portion of said cam slot crosses the line of thrust between the tie elements and thereby causes the line of thrust to intersect said first pivot element during the swinging movement of the lever to and from the tightened tie position, and means for limiting movement of said lever after said major portion of the cam slot has crossed the line of thrust in moving toward the tightened tie position of the lever.

4. A load binder mechanism of the type adapted to develop and exert tensile force along a line of thrust extending between two tie elements and comprising, in combination, a unitary lever having long and short arm portions on opposed sides of a fixed pivot element which serves as a fulcrum for swinging movement of said lever by which the operation of the mechanism is effected, said long arm portion of the lever serving as a handle for applying force thereto, said short arm portion having a curved cam slot therein, one end of which curved cam slot is near said fixed pivot element, and which cam slot extends away from the fixed pivot element and has a second pivot element mounted therein for movements along the cam slot toward and from the fixed pivot element as the lever is swung around the fixed pivot element, one of said tie elements being connected to the fixed pivot element and extending therefrom in one direction of thrust, the other of said tie elements being connected to the movable second pivot element and extending in a direction of thrust opposed to that aforementioned, said curved cam slot having a concavely curved cam surface against which the movable second pivot element is held in contact by the thrust applied thereto during swinging movements of said lever, said lever having loose and tightened positions in which the handle extends in generally opposite directions from the fixed pivot element, and the curvature of said cam surface being sufficient to restrain the movements of the movable second pivot element along the cam surface in relation to the angular swinging movement of the lever during the mid-regions of the movements of the the lever between said loose and tightened positions.

5. A load binder mechanism as defined in claim 4, and wherein said concavely curved cam surface is arcuate and has tangents which progressively become normal to the direction of thrust on the movable second pivot element.