US2938596A - Collapsible trestle - Google Patents

Description

May 31, 1960 A. B. VANYO COLLAPSIBLE TRESTLE Filed Nov. 7, 1956 INVENTOR. ANDREW B.VANYO ATTORNEY Unite My invention relates to supports, and more particularly, to a collapsible plank horse adapted for use in forming scaffolding and the like.

Heretofore it has been suggested to provide collapsible trestles designed for forming scafiolding, for example, a sawhorse or similar support, from lumber or other structural member. In the prior art arrangements, of which I am aware, it has been proposed to clamp the plank or other structural member either directly between the upper ends of the pivoted legs of the trestle or between extensions attached to or formed integral with said ends, the clamped end portion of the plank being additionally supported on a cross-member attached to the trestle legs in the vicinity of the clamping ends thereof. With either of the above noted constructions, due to the pivoting arrangement of the legs, the opening between the free ends thereof is of limited extent, and accordingly, planks of a substantially fixed width are required in forming the scaffolding or sawhorse.

In order to accommodate planks or other structural members of random widths, it has been suggested to construct the trestle with adjustable legs, that is to say, adjustably separated to provide a larger opening between their clamping ends, the adjusting means generally comprising a transverse arm or arms associated with the legs, and having spaced openings to receive a bolt or other fastening means.

While the collapsible trestles of the type referred to above are satisfactory to the extent that they function for their intended purposes, they are open to certain objections which are inherent in their design and construction. The trestles in which no provision is made to accommodate planks of various widths, do not meet with favor, for the reason that the users, carpenters, plasterers, and others, must maintain a supply of planks of predetermined width to be transported to and from the job, with the trestles. In other words, they cannot make use of available planks of random widths, usually found at the building site. Additionally, under some circumstances, it may be found desirable or expedient to use planks of a width greater than or less than the standard for which the trestle was designed. Trestles having adjustable legs of the character wherein a slotted arm is associated with the legs are not readily adjustable since for each change of width it is necessary to remove the bolts, bring the openings into register after the desired spacing has been obtained, and then replace the bolts. Also, with these arrangements the amount or degree of spacing for each adjustment is determined by the distance between the centers of the openings in the arms. Accordingly, a gradual increase or decrease in width of the plank supporting opening cannot be obtained.

After considerable experimentation, I have found that in order to provide desired clamping action between the free ends of the legs of a plank horse and the sides of the plank, that the plank, when supported in the operative position, should lie flat, and that the clamping forces transmitted through the upper ends of the legs must be States Patent '0 "ice to obtain, it is necessary that adjustment of the legs be gradual, both at the top and bottom of the support. Accordingly, the collapsible plank horse of the present invention is provided with improved leg adjusting means, whereby the width of the plank receiving opening of thesupport may be gradually varied over a comparatively wide range, with simultaneous proportional variation of the distance between the supporting ends of the legs.

An object of my invention is to provide an improved collapsible trestle.

Another object of my invention is to provide a collapsible trestle for use in forming scaffolding, wherein the plank or other structural member is securely clamped and supported between the free ends of the legs of the trestle.

Yet another object of my invention is to provide a collapsible trestle adapted for use with planks of various widths.

Still another object of my invention is to provide a collapsible trestle having means for adjusting the width of the plank receiving opening, with simultaneous proportional variation of the distance between the support ing ends of the legs.

A still further object of my invention is to provide an improved collapsible trestle which is strong and sturdy in construction, easily assembled and adjusted to desired plank width without the use of special tools, and not liable to get out of order even after long and continued use.

With these and other objects in view, which may be incident to my improvements, the invention consists in the parts and combinations to be hereinafter set forth and claimed, with the understanding that the several necessary elements, comprising my invention, may be varied in construction, proportions and arrangement, without departing from the spirit and scope of the appended claims.

In order to make my invention more clearly understood, I have shown in the accompanying drawings means for carrying the same into practical effect, without limiting the improvements in their useful applications to the particular constructions, which for the purpose of explanation, have been made the subject of illustration.

In the drawings:

Figure 1 is a front elevational view of a collapsible support of the present invention, showing a plank or the like, in the seated clamped position thereon;

Fig. 2 is a top plan view of the support shown in Fig. 1, with the plank removed;

Fig. 3 is a sectional view taken along line 3-3 0 Fig. 2;

Fig. 4 is an enlarged sectional view taken along line 44 of Fig. 3;

Fig. 5 is a sectional view along line 5-5 of Fig. 3;

Fig. 6 is a front elevational view of a modified form of support; and

Fig. 7 is a rear elevational view, partly in section, of the support shown in Fig. 6. a

Referring to the drawings, and more particularly t Figs. 15, my improved collapsible trestle, or plank horse comprising leg members 1, formed from a structurally strong, light weight metal or metal alloy, each of the legs being of Ushape in cross section having a flat rectangular shaped bottom portion 2 (Fig. 4) and like shaped side flanges or legs 3. As will be seen in Figs. 1 and 2, the upper portion of each leg is conformed to receive a plank supporting member 4, having a bottom flange 5 and a side flange 6, the side flange beingprovided with spaced pointed projections 7, adapted to grip the edge of a plank 8, as will be described hereinafter.

In fitting the member 4 to the top of the leg, a portion of each of the side flanges Q may be removed or merely turned back at right angles to the plane of the flange,

thus formingashelf upon which the bottom flange- 5 of the plank support may rest, said support then being welded or-otherwise secured in seated position on the leg. The lower portion 'of-each leg is angularly disposed with respect to its top portion, and is provided-with afoot 9 formed from rubberized fabric or other suitable mate rial, adapted for frictional engagement with the surface upon which the plank horse is supported.

'The' legs are connected by means of a bottom brace 10, and a top brace 11, the latter also incorporating means for adjusting the -width of the plank receiving opening. The bottom brace, which is designed to be collapsed, comprises achannel shaped arm 12 pivotally attached as at 13, to theside flanges 3 of one of the legs and overlapping a similarly shaped arm 14, pivotally attached to the flanges of the other leg at 15, the arms being connected by a pivot pin 16. It will be noted that the side flanges of arm'14 are formed with apposed slots 16 to permit limited sliding movement of this arm with respect to arm 12, and that by tightening pin 16 suflicient friction is developed between the overlapping contact surfaces of the'arms to resist relative movement thereof when the trestle is adjusted to its plank supporting position. I A suitable hook 17, formed on arm 12 provides means for raising this arm to break the joint, when it isdesired to collapse the legs.

The top brace 11 comprises a channel shaped arm 18, Fig. 4, pivotally attached to side flanges 3 of the legs 1, by means of pins or rivets 19, and a similarly shaped arm 20, pivotally attached to the flanges 3 of theother leg by means of a pin 21, the arm 13 being arranged in telescoping relationship with respect to arm 20, the arms being maintained ,in seated position by means of spaced bands or clips 22 secured to the sides of. member 18. Fixedly mounted between the sides of arm 20 is a nut 23, adapted to receive the threaded end portion 24 of a rod 25, supported in a bearing member 26, carried by bottom flange 2 of the leg, the end of rod 25 projecting outwardly beyond said flange and having a capstan type head 27, with associated bar 28, whereby the rod may be rotated.

, In forming a scaffolding it will be understood that at least two trestles are used to support the plank in the vicinity of the ends thereof, however, additional trestles maybe positioned intermediate of the plank ends, if desired. To assemble the scafiolding a plank of suitable dimensions is selected and an end portion thereof placed within the opening between side flanges 6 of the plank support members 4 of a trestle. The width of the opening is then adjusted by turning the capstan bar 28 to rotate rod 25in a direction to increase or decrease the horizontal distance between the flanges 6, and to bring pins or prongs 7 into contact with the sides of the plank. Thereafterward, the bottom brace is broken by pulling upwardly on hook member 17, thus causing the pertions of the legs below the brace 11 to move inwardly and portions above the brace to move outwardly. The capstan 27 is then rotated to decrease the opening between flanges 6 by an amount approximately twice the length of one of the prongs orpins 7; The screw pin is having been adjusted to clamp the overlapping flanges of the arms of brace 10, the brace is returned to its original horizontal position, the upper portions 29 of the legs moving inwardly and clamping the plank in seated position on supports 4, with prongs 7 embedded in the sides of the plank, as shown in Figs. 1 and 3. After one end of the plank has been secured to a trestle, as above described, the opposite end is attached to a second trestle in the same manner.

It will thus be seen that, by reason of the angularity of the legs, in conjunction with the construction and arrangement of the braces, the plank is securely clamped the improved variable adjusting means permits the use of planks of random widths. Additionally, when the trestles are assembled with a plank in load supporting position thereon, a rigid scaffolding is obtained which may be readily moved about, as required. The scaffolding may also ,be readily dismantled and arranged into compact units for storage or transportation.

Referring to Figs. 6 and 7 there is shown a modified form of trestle wherein the top brace 30 is formed from a strip of spring steel, bent into an arcuate shape as shown, one end of the strip being pivotally supported between flanges 3 of one of the legs by means of a pin 31, the opposite end of the strip being fastened between the flanges of the other leg by welding, as at 32. The remaining elements of the modified trestle are the same as described in connection with the preferred embodiment of Figs. l-5, with the exception of the lower brace 10, which is not adjustable as to its over-all length: With the modified construction, by forcing strip 3% downwardly the upper ends of the legsmay be sprung outwardly a suflicient distance to accommodate boards or planks of width slightly greater than the normal Width of opening between the side flanges 6. It is contemplated that a plank of selected width will be provided with each pair of trestles, and that by springing the legs, the end portions of the plank may bequickly and easily seated in clamped position on and between the plank receiving supports.

7 There has been described and illustrated a device capable of performing all of the specifically mentioned objects of this invention as well as others which are apparent to those skilled in the art. Various uses of the present invention may be made employing the described structure. Accordingly, it is apparent that variations as to operation, size and shape, and rearrangement ofelements may be made without departing from the spirit of the invention. Accordingly, limitation is sought only in accordance with the scope of the following claims.

What is claimed is: 1. A plank horse of the character described, comprising a pair of symmetrically shaped leg members, including upperand lower portions, formed from metal, each of said members comprising a rectangular shaped bottom flange and a pair of side flanges arranged at right angles to the plane of said bottom flange, the lower portion of each leg being angularly disposed with respect to the upper portion thereof, a'plank supporting member secured to the top of each upper leg portion, an extensible, collapsible brace member positioned between the lower portions of the legs, a second brace member positioned between the upper leg portions, said second brace member comprising an outer arm and an inner arm arranged in telescoping relationship, the end of each arm remote from its over-lapping portion being pivotally connected between the side flanges of opposite legs, a threaded member secured to the inner arm, a rod having an end portion in threaded engagement with said member, the opposite end of the rod projecting beyond the plane of the bottom flange of one of the legs, and means attached to said end of the rod-to" rotate the same, whereby to vary the horizontal distance between'the plank supporting members. 1

2. A plank horse of the character described, comprising a pair of symmetrically shaped leg members, including upper and lower portions, formed from metal, each of said members comprising a rectangular shaped bottom flange and a pair of side flanges arranged at right angles to the plane of said bottom flange, the lower portion of each leg being angularly disposed with respect to the upper portion thereof, a plank supporting member secured to the top of each upper leg portion, said member having a horizontal flange forming a seat for a plank and a vertical flange having a plurality of spaced prongs adapted for engagement with an edge of. a plank, an

.in substantially flat position on the supports 4, and that extensible collapsiblebrace member positioned between 5 the lower portions of the legs, a second brace member References Cited in the tile of this patent positioned between the upper leg portions, said second UNITED STATES PATENTS brace member comprising an outer arm and an mner arm arranged in telescoping relationship, the end of each arm 23097 q 1949 remote from its over-lapping portion being pivotally oon- 5 829548 Srfmh 1906 nected between the side flanges of opposite legs, a thread- 947464 Vlckers 1910 ed member secured to the inner arm, a rod having an 1'014'554 1912 end portion in threaded engagement with said member, 1,685,283 P P Sept 1928 the opposite end of the rod projecting beyond the plane 25731740 sp lkmgs N 1951 of the bottom flange of one of the legs, and means at- 10 2644726 Mmer July 1953 tached to said end of the rod to rotate the same, whereby 2'689154 Rfdler Sept to vary the horizontal distance between the plank sup- 8'771 ORourk 1955 porting members. 2,706,661 Clayton -n. Apr. 19, 1955

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