US2819931A

US2819931A - Sawhorse toggle clamp

Info

Publication number: US2819931A
Application number: US441567A
Authority: US
Inventors: Robert L Chesney
Original assignee: FRANK A DROESCH
Current assignee: FRANK A DROESCH
Priority date: 1954-07-06
Filing date: 1954-07-06
Publication date: 1958-01-14
Anticipated expiration: 1975-01-14

Description

United States Patent SAWHORSE TOGGLE CLAMP Robert L. Chesney, Los Angeles, Calif., assignor, by mesne This invention relates to improvements in trestles, e. g. sawhorses, and more particularly to a device for securing legs to a cross piece to form a trestle.

-It is an object of this invention to provide a trestle, which can be readily set up as a sturdy and substantially rigid supporting structure, and which can be knocked down easily and quickly to facilitate storage and transportation thereof.

. Another object of the invention is to provide a new and improved device having a toggle joint construction for securing and locking legs to a cross piece to form a trestle.

A further object of the invention is to provide a clamp ing device of the above mentioned character, which is rugged and simple in construction and which because of its simplicity in construction can be produced inexpensively with a view to supplying an eflicient clamping device for trestles at small cost.

Further objects and advantages of the invention will become apparent during the course of the following part of this specification, wherein the details of construction and mode of operation of a preferred embodiment thereof are described with reference to the accompanying drawing, wherein:

Figure No. l is a perspective view of a portion of a sawhorse, in which the legs thereof are secured to a cross piece by means of a toggle clamp embodying my invention;

Figure No. 2 is an end elevation on an enlarged scale of a portion of the sawhorse, showing certain details of construction of the toggle clamp;

Figure No. 3 is a side elevation of the clamp, as taken on line 33 of Figure 2; and

Figure No. 4 is a bottom plan view of the clamp in extended position, taken on line 4-4 of Figure 2.

Referring to the drawings more in detail, reference numeral 10 designates a sawhorse comprising a horizontal cross piece 11, two legs 12 and 13, and a clamp 14 which releasably secures the legs to the cross piece. The cross piece and the legs of the illustrated embodiment are pieces of lumber of rectangular cross sections. In cases where it is desired to construct a sawhorse of the type as is generally used by carpenters, it will be found that two by fours serve well for the legs and cross piece.

The clamp 14 comprises two

channels

16 and 17 which serve as sockets for the ends of legs 12 and 13 respectively. The channels are formed preferably from sheet steel, or other suitable material, and are substantially similar to each other in size and shape, whereby a description of the details of one is applicable to the other. Thus, the details of construction of channel 17 are described hereinafter and the reference numerals which designate respective component parts of channel 17 are used again to designate like parts of channel 16; however, in the case of channel 16 a prime is applied to the reference numerals thereof. Channel 17 is shaped by bending the sheet from which it is formed, along parallel lines 18 and ice 19, to define a bottom wall 20 for the channel and two

side walls

21 and 22, extending in respective planes substantially at right angles to the bottom wall. The

side walls

21 and 22 are similar to each other in size and form and, therefore, the details of construction of but one such side wall are described. Thus, side wall 21 has a pair of spaced apart slits 24 and 25, cut inwardly from its longitudinal edge to provide a free portion between the slits. This portion is bent inwardly as on line 27, to form a flange 28 for holding a leg of the sawhorse straight within the channel.

Adjacent to slit 24 is an ear 30 providing a means for pivotally attaching the channel 17, as with a rivet or pin 31, to a corresponding car 30' on the channel 16. The ear 30 is set back from the plane of the side wall 21, by an offset 32, so that the surfaces between the pivotally connected ears 30 and 30' will lie flush against each other.

That portion of the channel extending upwardly beyond the ear 30, for convenience in description, is referred to as a jawfor the clamp. As best shown in Figure No. 2 of the drawing, the clamping edge for such jaw is defined by a notch 34 which receives the cross piece between opposite jaws of the clamp. Each notch is defined by the upper edge 35 of the ear 30, and edge portions 36, 37, and 38. The edge portion 36 is disposed at an angle with respect to the plane of bottom wall 20 such that when the channels are spread apart the edge '36 will be disposed in a horizontal plane, thereby forming a rest for the under surface of the cross piece. The edge portion 37 extends upwardly from the edge portion 36 and at right angles thereto, so that when the clamp is secured to the cross piece, the edge 37 will lie in a vertical plane against a side face of the cross piece. Edge portion 38 is inclined from its point of intersection with edge 37 away from the bottom wall 20 of the channel to define a tooth 39 which cuts into the cross piece when the clamp is expanded, as is described more fully hereinafter. v

In the bottom wall of the channel there is a lug 41 struck from the bottom wall, with one side of the lug remaining integral with the bottom Wall. The lug is bent inwardly of the channel and extends substantially at right angles to the bottom wall, thereby serving as a stop against which the top end face of leg 13 abuts when the leg is fitted into the channel. The line on which the lug 41 is bent lies in a plane which extends substantially perpendicular to bottom wall 20 and contains the points 42 at which the edges 36 and 37 intersect. Thus, when a leg for the sawhorse is fitted into the channel, the leg will extend up to the points 42, 42' on respective side walls of the channel, whereby the cross piece 11 rests on and is supported by the leg. Also struck from the bottom wall 20 and bent inwardly of the channel are two projecting teeth 43, which serve to bite into an end edge of the leg 13 to secure the leg within the channel.

As thus far described it is apparent that the clamp of this invention operates as a pincers. When the channels are spread apart at their lower ends the jaw-s thereof move toward each other to cut into the cross piece of the sawhorse. In order to function satisfactorily, a sawhorse must be of sturdy and rigid construction, and to this end, the clamp of this invention is so designed that its jaws may be forced together easily and simply to bite into the cross piece of the sawhorse and firmly grip it,- and the clamp holds the legs of the sawhorse securely in their respective channels of the clamp, thereby tightly securing the legs to the cross piece. Furthermore, the clamp of this invention is designed to become locked when spread to its clamping position so that the legs and cross piecemay not inadvertently become loose from each other. In addition to these advantageous characteristics the clamp is adapted to be made loose quickly so as to permit easy disassembly of the sawhorse when desired.

of the channels such that the clamp forms an A-frarne type of structure when the sawhorse is assembled.

The plate 45 is substantially rectangular in shape and has two

side arms

46 and 46 integral with opposite ends of the plate and bent upwardly from the plane of the 'plate so as to lie in respective planes at right angles to the plate. These side arms extend beyond the line of a side edge 47 of the plate and are pivotally secured at their outer ends on the outside faces of respective side wallsof channel 17 as with a pin or rivet such as that designated by numeral 48. The plate 45 is attached to the other channel 16 by means of a pair of links, one of which is shown at 49. One end of link 49 is pivotally secured by pin 50 to the outside face of a side wall of channel 16, and the other end of the link is pivotally secured to the arm 46 by a pin 51.

The plate 45 is of suflicient length to extend beyond the links 49 and thus the end edges of the plate strike against the links to prevent the plate from swinging upwardly past the links when the channels are spread apart to their outer limit. The pin 51 is spaced above the plate 45 by a distance which is greater than the distance of the pins 48 and 50 above the plate. Thus in spreading the channels apart the plate is swung on its pivots 48 until it strikes against the bottom edges of the links 49, whereupon the center of pin 51 will have become positioned slightly above a line passing through the centers of pins 48 and 50, i. e. the pin 51 becomes positioned past center of the pins 48 and 50, thereby locking the channels of the clamp in their spread apart position. Locking of the clamp is made more secure by engagement of a dimple 52, projecting inwardly from the side arm 46, with a depression or slot 53 formed in the outside face of the link 49.

The hinge or pivoted joint at the pin 51 constitutes a knee for the toggle joint of the clamp. The plate 45 as viewed in Figure 2, extends leftwardly of such knee and thus provides a convenient handle for applying force to the knee to close or open the jaws of the clamp. Strengthening ribs such as those shown at 55 are preferably formed in the plate to resist bending of the plate.

Each side wall of each channel has a lever arm pivotally secured thereto and of sufiicient length to extend into respective channels for gripping the legs of the sawhorse and thereby rigidly holding the legs in place in the channels. Such lever arms are shown at 57 and 57'. The arm 57 is secured to side wall 21 by a pivot pin 58 and the arm 57 is secured to a corresponding side wall of channel 16 as with pivot pin 58'. At their ad joining ends the lever arms are secured together by a pivot pin 59. The opposite ends of the lever arms project into their respective channels and are pointed as designated at 60 whereby they bite into the legs of the sawhorse or become wedged tightly against the side faces of the legs to hold the legs firmly within the channels when the channels are spread apart by operating the plate handle 45 of the toggle joint. The lever arms are set back inwardly from the planes of their respective channel side walls by means of joggles such as designated at 61-61'.

For purposes of economy in materials, the lever arms and the links 49 may be blanked out from the bottom walls of the channels, leaving voids 63 in such bottom wall.

To construct a sawhorse with clamps as provided by this invention, a cross piece of desired length and width is placed on a floor and a clamp is positioned on the cross piece with the jaws of the clamp extending downwardly along opposite side faces of the cross piece. An

operator then inserts a leg into each channel of the clamp and pushes downwardly on the legs until their end faces abut against the lugs 41 in the channels. Such downward force on the legs causes the teeth 43 to cut into the end edges of the legs adjacent the bottom walls of the respective channels, and the wood of the legs is thereby bulged outwardly into the openings in the bottom walls 20, from which the teeth are bent. The teeth 43 thus serve to hold the inner ends of the legs securely in their respective channels. To prevent the teeth 43 from being bent further inwardly of the channels by the force exerted longitudinally on the legs, the teeth are bent from the bottom walls 20 at an angle of approximately 10 from their respective bottom walls and thus they cut into the legs in a direction essentially longitudinal of the legs.

With the legs thus extending upwardly from the cross piece, the operator spreads the legs apart and presses down on the handle or plate of the toggle joint as with his foot, to close the jaws of the clamp against opposite side faces of the cross piece so that teeth 39 of the jaws will cut into the cross piece. In this operation the legs become wedged together along their inside end edges, whereby they cooperate as a unitary structure for supporting the cross piece and are further tightened in the channels. Spreading of the legs also moves the lower ends of the lever arms 57 and 57' apart so that the free ends of the lever arms (points cut into the legs and thereby secure the legs in the channels. Pressing down on the toggle joint moves the knee of the joint downwardly past center of the pins 48 and St) to lock the clamp agianst being inadvertently released from its grip on the cross piece and the legs. Engagement of the dimples 52 in the slots 53 assists in holding the clamp in its locked position.

To complete the sawhorse, another pair of legs is secured to the cross piece with a second clamp as in the manner described above. The sawhorse is then ready to be turned upright and put into use.

Dissembly of the sawhorse is simple and easy, requiring merely that the toggle handles on the clamps be lifted in a direction away from the hinges or pins 31, to open the jaws of the clamps and release the legs from the lever arms 57.

The toggle joint construction of the clamp of this invention gives enormous mechanical advantage, and as the clamp is designed so as to be operated by ones foot if desired, it is adapted to receive a strong force against the knee of the toggle joint and to translate such force to a direction such that the jaws of the clamp will cut deeply into the rcoss piece and the lever arms will cut deeply into the legs of the sawhorse to insure a tight and sturdy assembly of the legs and cross piece. It is to be noted, too, that the tight grip of the clamp to the cross piece as is made possible by the toggle joint construction of the clamp, permits the jaws of the clamp to be made relatively short so that their ends will be spaced from the top surface of the cross piece. Thus, in using the sawhorse as a support for boards or planks to be sawed, the likelihood of striking a clamp with a saw and thereby dulling the saw, is greatly reduced.

It is to be understood that the form of my invention, herein shown and described, is a practical and preferred example of the same, and that changes may be resorted to within the scope of my invention, which is not limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent structures.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

l. A clamp for anchoring legs to a cross piece of a trestle, comprising a pair of channels, each channel having a back wall and a pair of side walls, pivot means securing the side walls of one channel to the side walls of the other channel, that portion of each channel above said pivot means constituting a jaw, said jaws being adapted to straddle the cross piece, that portion of each channel below said pivot means constituting a socket, said sockets being adapted to receive the legs, a pair of arms, means pivotally securing each of said arms to respective side walls of one of the channels in the socket portion thereof, a pair of links, each of said links being pivotally secured to respective side walls of the other of the channels in the socket portion thereof, pivot means securing each of the arms to respective links, a pair of lever arms for each channel, means pivotally securing each of the lever arms intermediate its ends to respective side walls, means pivotally securing the lever arms of one channel to respective lever arms of the other channel, whereby the lever arms project into respective channels for engaging the legs when said socket portions are spread apart.

2. A clamp for anchoring legs to a cross piece of a trestle, comprising a pair of channels, each channel having a back wall and a pair of side walls, first pivot means securing the side walls of one channel to the side walls of the other channel, that portion of each channel above said pivot means constituting a jaw, each of the jaws having a notch formed therein for receiving the cross piece between the jaws, said notches defining horizontally extending edge portions adapted to lie flush against the under face of the cross piece and vertically extending edge portions adapted to lie flush against respective side faces of the cross piece, a tooth projecting from each jaw and adapted to cut into the cross piece,

that portion of each channel below said pivot means constituting a socket, said sockets being adapted to receive the legs, a pair of arms, second pivot means securing each of said arms to respective side walls of one of the channels in the socket portion thereof, a pair of links, third pivot means securing each of said links to respective side walls of the other of the channels in the socket portion thereof, fourth pivot means securing each of the arms to respective links and moveable in a direction away from the said first pivot means and beyond a line passing through the said second and third pivot means, a pair of lever arms for each channel, means pivotally securing each of the lever arms intermediate its ends to respective side walls, fifth pivot means securing the lever arms of one channel to respective lever arms of the other channel and moveable in a direction from said line toward the said first pivot means, whereby the lever arms project into respective channels for engaging the said legs when said socket portions are spread apart.

3. A clamp according to claim 2 and including stop means projecting inwardly from respective back walls of said channels and aligned with respective intersections of said horizontally extending edges and said vertically extending edges.

4. A clamp for anchoring legs to a cross piece of a trestle, comprising a pair of channels, each channel having a back wall and a pair of side walls, first pivot means securing the side walls of one channel to the side walls of the other channel, that portion of each channel above said pivot means constituting a jaw, said jaws being adapted to clamp against opposite side faces of the cross piece, that portion of each channel below said pivot means constituting a socket, said sockets being adapted to receive end portions of the legs, and toggle joint means positioned between said channels and comprising a plate, a pair of arms integral with the plate and extending in a direction of the plane of the plate and beyond an edge of the plate, second pivot means securing said arms to respective side walls of one of the channels, a pair of links, third pivot means securing each of the links to respective side walls of the other of the channels in the socket portion thereof, fourth pivot means securing each of the arms to respective links and moveable in a direction away from the said first pivot means beyond a line passing through said second and third pivot means, said plate extending outwardly beyond the links, a pair of lever arms for each channel, means pivotally securing each of the lever arms intermediate its ends to respective side walls, fifth pivot means securing the lever arms of one channel to respective lever arms of the other channel and moveable in a direction from said line toward said first pivot means, whereby the lever arms project into respective channels for engaging the legs when the socket portions of the channels are spread apart.

References Cited in the file of this patent UNITED STATES PATENTS 1,996,761 Gould et al. Apr. 9, 1935 2,105,979 Manley Jan. 18, 1938 2,545,767 Dalton t Mar. 20, 1951 2,555,503 Morton June 5, 1951 2,561,864 Hollywood July 24, 1951