US3881690A

US3881690A - Fence stretcher

Info

Publication number: US3881690A
Application number: US444416A
Authority: US
Inventors: Jr James E Combs
Original assignee: Individual
Current assignee: Individual
Priority date: 1974-02-21
Filing date: 1974-02-21
Publication date: 1975-05-06
Anticipated expiration: 1992-05-06

Abstract

A tool for stretching fence or the like which employs an improved cam member of elongated, transverse, cross-sectional configuration having a pair of opposed, transversely arcuate, longitudinally extending, outermost faces, one on each side respectively of its longitudinal axis, with one of the faces being offset in one direction relative to the axis and the other of the faces offset in the opposite direction relative to the axis.

Description

O United States Patent 1 1 1111 3,881,690 Combs, Jr. May 6, 1975 FENCE STRETCHER 3,211,426 10/1965 Handley 254/83 [76] Inventor: James E. Combs, Jr., PO. Box 81,

Farley Mo 64028 Primary Examzner-Al Lawrence Smlth Assistant ExaminerRobert C. Watson Flled? 1974 Attorney, Agent, or FirmSchmidt, Johnson, l-lovey & 21 Appl. No.: 444,416 wlllams 7 [52] US. Cl 254/83; 24/132 WF [5 1 ABSTRACT 51 1:11.01 B66f 19/00 A for stretchmg fence or the Whlch employs 581 Field of Search 254/83, 77; 24/132 WF, impmved cam member of elongated, transverse 24/132 WA cross-sectional configuration having a pair of opposed,

transversely arcuate, longitudinally extending, outer- [56] References Cited most faces, one on each side respectively of its longitudinal axis, with one of the faces being offset in one UNITED STATES PATENTS direction relative to the axis and the other of the faces offset in the opposite direction relative to the axis. 2,77'21070 11/1956 Stevenson:..:... 254/83 6 Claims, 4 Drawing Figures FENCE STRETCHER This invention relates to the field of wire or fencstretching devices and, more particularly, to an improved device which uses a unique camming action, generated by a cam constructed in the form of a pair of opposed bodies having transversely arcuate, longitudinally extending, outermost faces, one on each side respectively of the longitudinal axis of the cam, with one of the faces being offset in one direction relative to the axis and the other of the faces offset in the opposite direction relative to the axis to effectively grasp the fence or wire to be stretched.

The use of some form of cam between a baseplate and a generally L-shaped projection on the baseplate extending in the direction of desired stretching to effect a camming or clamping action of a fence onto the plate is well known in the prior art. One such device which typifies this method is shown in US. Pat. No. 3,21 1,426, which issued to F. O. Handley on Oct. I2, 1965. The Handley device employs an elongated baseplate, a finger-like projection extending outwardly from the front of the baseplate and thence generally in the direction of desired stretching, and a generally C- shaped member having intricately configured surfaces and a head portion for engaging the interior region of the outwardly extending projection for effecting a clamping action toward the baseplate by rocking movement relative to the latter. Another device exemplifying current practices is shown in US. Pat. No. 1,91 1,274, issued to J. M. Handley on May 30, 1933. This device uses an elongated baseplate and L-shaped projections extending from the rear of the baseplate in a direction opposite to the direction of desired stretching, but requires a complexly shaped crank-like member which is provided with longitudinal regions of differing diameters including a cylindrical region of lesser diameter than that of the main body of the cam and eccentrically mounted on the latter. The smaller of such longitudinal regions is adapted to engage the L-shaped projection, while the larger diameter main region is intended to move into engagement with the fence.

The present invention also uses an elongated baseplate and a plurality of L-shaped finger-like projections extending outwardly from the rear of the plate. However, the present invention employs an improved cam mechanism in conjunction with projections that terminate with legs extending oppositely to the direction of desired stretching. The improved cam mechanism is characterized by a transverse, cross-sectional configuration that is uniform throughout the length of the cam but is transversely elongated. The preferred form of improved cam employs a pair of interconnected elongated sections that are respectively of generally semicylindrical form and are disposed in opposed, offset relationship to each other.

Accordingly, it is the primary object of this invention to provide an improved tool for stretching fence or the like employing less complex structures and relationships that render the tool more durable, reliable and efficient in use, as well as easire and more economical to manufacture by conventional production procedures.

It is another important object of this invention to provide such a tool which has a transverse cross-sectional configuration that is elongated and preferably in the form of a pair of opposed, offset, interconnected, generally semicircular sections.

Still another important object of this invention is to provide such a tool having a cam mechanism which offers a greater degree of cam efficiency and mechanical advantage than is attainable from cam mechanism employed in prior art tools for similar purposes. In the drawing:

FIG. 1 is a perspective view of a fence-stretching tool embodying the principles of my invention shown in its operative relationship with a portion of the fence being stretched and a source of pulling force;

FIG. 2 is a side elevational view of the fencestretching tool of FIG. 1;

FIG. 3 is an enlarged, cross-sectional view taken along line 44 of FlG. 2; and

FIG. 4 is a view similar to that of FIG. 3 with the hook lever shown in its clamping position.

The fence stretcher embodying the principles of my invention is generally designated by the numeral 10 in the drawing. The fence stretcher l0 broadly includes a channelshaped baseplate 12, a plurality of spaced fingers l4 suitably secured by welding or other means to the front edge 13 of the baseplate 12 and having a peripheral guide bar 16 interconnecting the forward edge of the fingers 14; a plurality of generally L-shaped finger-like projections 18 suitably secured by welding or other means to and extending outwardly from the side face 15 of the plate 12; a cam mechanism 20; and a hooked lever element 22 secured to and extending outwardly from the cam mechanism 20.

The fence stretcher 10 is used in conjunction with a tractor 24 (only partially shown in FIG. 1) to stretch fence 26 in order to eliminate any slack during installation of the latter on posts 28. The fence stretcher 10 may also be used equally well to stretch a single wire or cable, or the combination of a plurality of wire units. It should also be noted that the improved cam of the present invention may be used equally well with one or more L-shaped projections 18 and with any number of spaced fingers l4 and consequently should not be deemed limited by any number of L-shaped projections 18 or fingers 14.

The L-shaped projections 18 each include a first leg 30 extending laterally outwardly from baseplate l2 and a second leg 32 extending from the first leg 30 generally longitudinally of the baseplate l2 oppositely to the direction of desired stretching of the fence 26. The first leg 30 has a surface 34 facing toward the front of the plate 12. The second leg 32 has a surface 36 facing toward the baseplate 12.

The cam mechanism 20, which when fabricated is a unitary member, includes a first generally semicylindrical section 38 having an arcuate outer surface or face 39 and a second generally semicylindrical section 40 having an arcuate outer surface or face 41. The

sections

38 and 40 are interconnected with the first section 38 being in an opposed and relatively offset relationship with the second section 40 in such a manner as to present a pair of diametrically opposed, oppositely facing flat lands 43 and 45. The cam mechanism 20 is capable of being fabricated by several different methods: for example, the mechanism may be rolled at the factory to present a onepiece member having a pair of integral, offset, semicylindrical sections; or two semicylindrical sections may be rolled at the factory and then cut to the proper length and welded together at the lands 43 and 45 or attached by some other similar procedure in an offset relationship to present a similar configuration; or round stock may be bisected and subsequently rejoined by welding or the like in a slightly offset relationship to again present a cam member having a pair of opposed, offset sections of slightly less than semicylindrical form due to the bisecting of the round stock.

The hook-like lever element 22 includes a main body portion 42 extending outwardly from the first section 38 of cam 20 in a direction generally perpendicular to the greater transverse dimension of cam 20.

In use, a portion of the fence 26 is positioned over the peripheral guide bar 16 and along the fingers l4 and across the baseplate 12. The cam mechanism 20 with the lever element 22 attached thereto is inserted between the second leg 32 of the L-shaped projection 18 and face of the baseplate 12, as shown in FIG. 3. The tractor 24 is attached to the hook part of lever element 22 by suitable fastening means such as chains 46 or the like. The tractor 24 is then actuated, thus causing a pulling force to be exerted on the hook lever 22 in the direction of desired stretching, thereby swinging the lever element 22 and rotating the cam mechanism to a position wherein the main body portion 42 of the lever element 22 is in substantial alignment with the direction of desired stretching and wherein the greater transverse dimension of the cam 20 is generally perpendicualr to the baseplate 12 (as illustrated in FIG. 4).

The rotation of the cam mechanism 20 and the resultant shifting of the longer transverse dimension of the latter causes the arcuate face 39 of the first section 38 to engage the surface 34 of the first leg 30, a protruding extremity 50 of the first section 38 to engage the surface 36 of the second leg 32, and a protruding extremity 52 of the second section 40 to engage a portion of the fence 26 thereby clamping the fence to the surface 46 of the baseplate 12. Thus, it will be appreciated that

opposite extremities

50 and 52 of unitary cam 20 simultaneously bear oppositely against surface 36 of leg 32 and the portions of fence 26 overlying baseplate 12 to provide a very positive clamping action.

It is readily apparent that as the hooked lever element 22 is shifted to its clamping position as illustrated in FIG. 4, the cam will clamp the fence against the baseplate 12 with progressively increased force as face 39 slides along the

surfaces

36 and 34 of projection 18 and as the other face slides along the fence 26. it should also be clear to those skilled in the art from a study of FIGS. 3 and 4, and from a review of the above description, that the length of the main body portion 42 of the hook lever 22 with respect to the substantially lesser dimensions of the

sections

38 and 40, in view of the relationship between the various parts of the improved tool 10, provides a large measure of positive and direct mechanical advantage for immediately clamping the fence 26 onto the baseplate 12 when force is applied to lever element 22.

lt is, therefore, to be appreciated that the invention is adapted to achieve its objects in positive and straightforward manner with reliable structure that is economical to manufacture, simple in design, and which requires little or no maintenance.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

l. A fence stretching tool comprising:

an elongate base having normally front and rear lon gitudinal edges;

a series of aligned, generally L-shaped, rearwardly opening members projecting outwardly from said base,

each of said members having a first leg secured to said base adjacent said front edge and extending a crank on said cam for rotatably wedging the latter between said second legs and the base when a forwardly directed draft force is applied to the crank to pull said one face around against said first legs, said other face being continuous for the full length of the cam and including stretches directly between said members and the base to produce uniform clamping and stretching action all along a fenceinserted between said base and the cam.

2. A fence stretching tool as claimed in claim 1, wherein said first face in continuous for the full length of said cam.

3. An improved tool for use in stretching an elongated fence or the like, said tool including a plate adapted to be disposed to one side of the fence, generally L-shaped members on the plate each having a first leg projecting generally laterally from the plate and a second leg extending from the first leg generally parallel to said plate, a shiftable cam mechanism adapted to be disposed between the plate and the second leg and to be shifted into a position for clamping the fence between the plate and said mechanism, and force transmitting means for interconnecting said mechanism to a draft source, wherein the improvement comprises the provision, in combination of:

said generally L-shaped members in which the second leg extends from the first leg in a direction generally opposite the direction of desired stretching of the fence; and

said cam mechanism in which is included an elongated cam member having a portion thereof adapted to be disposed between the plate and the second leg with said portion having its transverse cross section elongated and of length at least as great as the distance between the plate and the second leg, and a lever element secured to the cam member and extending laterally from said member at a substantial angle from the longer transverse cross sectional dimension of said portion, said element being adapted to have a force coupled therewith in said direction of desired stretching of the fence and for rotating said cam member into a position in which one extremity of the longer transverse cross sectional dimension of said portion engages said second leg and the opposite extremity thereof engages the fence to clamp the same between said opposite extremity and said plate.

said portion of the cam mechanism having generally offset and oppositely facing surfaces and comprising a pair of offset, opposed, interconnected, semicylindrical sections.

I transmitting means for interconnecting said cam to a 5 6 4. In a fencestretcher having an elongated base, a 7 said cam being provided with a pair of diametrically number of pro ections secured to the base, an elonopposed, oppositely facing, flat lands coextensive gated, rotatable cam extending longitudinally of the i l h h i h base between the latter and the projections, and a force Said lands intersecting said faces to f opposite tremities.

5. In a fence stretcher as claimed in claim 4, wherein said cam is provided with a pair of substantially identical, solid sections extending longitudinally thereof, said sections being generally semicircular in transverse one direction relative to said axis and the other of cross sfection f having a planar interface Said lands said faces offset in the opposite direction relative extendmg radally outwardly at Said interface" to said axis whereby when the fence is between 6. In a fence stretcher as claimed in claim 5, wherein the cam and said base rotation of the cam in said sections are rigidly interconnected at said interdirection will clamp the fence against the base facewith progressively increased force as said one face slides along the projections and said other face slides along the fence,

draft source, wherein the improvement comprises:

providing said cam with a pair of opposed, transversely arcuate, longitudinally extending, outermost faces, one on each side respectively of its longitudinal axis, with one of said faces offset in 10

Claims

1. A fence stretching tool comprising: an elongate base having normally front and rear longitudinal edges; a series of aligned, generally L-shaped, rearwardly opening members projecting outwardly from said base, each of said members having a first leg secured to said base adjacent said front edge and extending laterally therefrom and a second leg extending rearwardly from said first leg toward said rear edge; an elongated rotatable cam extending longitudinally of said base behind said first legs of the members, said cam having a pair of diametrically opposed, transversely arcuate, longitudinally extending, outermost faces, one on each side respectively of its longitudinal axis, with one of said faces offset in one lateral direction relative to said axis and the other of said faces offset in the opposite lateral diRection relative to said axis; and a crank on said cam for rotatably wedging the latter between said second legs and the base when a forwardly directed draft force is applied to the crank to pull said one face around against said first legs, said other face being continuous for the full length of the cam and including stretches directly between said members and the base to produce uniform clamping and stretching action all along a fence inserted between said base and the cam.

3. An improved tool for use in stretching an elongated fence or the like, said tool including a plate adapted to be disposed to one side of the fence, generally L-shaped members on the plate each having a first leg projecting generally laterally from the plate and a second leg extending from the first leg generally parallel to said plate, a shiftable cam mechanism adapted to be disposed between the plate and the second leg and to be shifted into a position for clamping the fence between the plate and said mechanism, and force transmitting means for interconnecting said mechanism to a draft source, wherein the improvement comprises the provision, in combination of: said generally L-shaped members in which the second leg extends from the first leg in a direction generally opposite the direction of desired stretching of the fence; and said cam mechanism in which is included an elongated cam member having a portion thereof adapted to be disposed between the plate and the second leg with said portion having its transverse cross section elongated and of length at least as great as the distance between the plate and the second leg, and a lever element secured to the cam member and extending laterally from said member at a substantial angle from the longer transverse cross sectional dimension of said portion, said element being adapted to have a force coupled therewith in said direction of desired stretching of the fence and for rotating said cam member into a position in which one extremity of the longer transverse cross sectional dimension of said portion engages said second leg and the opposite extremity thereof engages the fence to clamp the same between said opposite extremity and said plate. said portion of the cam mechanism having generally offset and oppositely facing surfaces and comprising a pair of offset, opposed, interconnected, semicylindrical sections.

4. In a fence stretcher having an elongated base, a number of projections secured to the base, an elongated, rotatable cam extending longitudinally of the base between the latter and the projections, and a force transmitting means for interconnecting said cam to a draft source, wherein the improvement comprises: providing said cam with a pair of opposed, transversely arcuate, longitudinally extending, outermost faces, on on each side respectively of its longitudinal axis, with one of said faces offset in one direction relative to said axis and the other of said faces offset in the opposite direction relative to said axis whereby, when the fence is between the cam and said base, rotation of the cam in one direction will clamp the fence against the base with progressively increased force as said one face slides along the projections and said other face slides along the fence, said cam being provided with a pair of diametrically opposed, oppositely facing, flat lands coextensive in length therewith, said lands intersecting said faces to form opposite extremities.

5. In a fence stretcher as claimed in claim 4, wherein said cam is provided with a pair of substantially identical, solid sections extending longitudinally thereof, said sections being generally semicircular in transverse cross section and having a planar interface, said lands extending radially outwardly at said interface.

6. In a fence stretcher as claimed in claim 5, wherein said sections are rigidly interconnected at said interface.