Patent Publication Number: US-5295558-A

Title: Scaffold platform brace

Description:
FIELD OF INVENTION 
     This invention is in the field of construction and particularly for use with scaffolds. There are two types of scaffolds which can be used in construction work. One type is the free standing rectilinear frame comprising four upright members with two vertically spaced horizontal members between each pair of vertical members to make the frame rigid. The frame may be four feet square or four by six feet. This type of frame is most useful in construction of building walls since there is no weight or tipping movement placed on the walls. The frame is also useful when performing overhead work. The other type of scaffolding is an L-shaped bracket which is secured to walls by bolts or the like. With either frame or bracket, a platform is required and is made up of wooden planks laid side by side in the nominal size of 2×8-2×10-2×12 and in lengths from 8 to 16 feet. Despite the thickness of the planks any length greater than 6 feet deflects when walked on creating a possible hazard, particularly in longer lengths when the deflection can develop a harmonic pattern. Thus, it is preferable to space the frames or brackets about 4-5 feet apart which increase the number of frames or brackets required and is an expense to the builder. The alternative to such numbers would be to use 3 inch planks but those are heavy and not easily moved by workmen. 
     SUMMARY OF THE INVENTION 
     The invention is a truss assembly for each plank in a scaffold platorm. It consists of a triangular center pedestal, two tension straps, a tension bar mounting plate on the pedestal and necessary bolts and nuts to secure the assembly to the underside of each plank. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention can be seen in the accompanying drawings which illustrate a currently preferred embodiment. 
     FIG. 1 is an elevation view of one side of the support pedestal of the invention when in the operative position, the view of the opposite side being identical. 
     FIG. 2 is an elevation view of one side of the entire assembly in the operative position, the view of the opposite side being identical. 
     FIG. 3 is a top plan view of FIG. 2. 
     FIG. 4 is a bottom plan view of FIG. 2. 
     FIG. 5 is a end view of the assembly installed on a footwalk plank. 
     FIG. 6 is an isometric view of the installation of the invention on the underside of a footwalk plank. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The principal element in the invention is the triangular central pedestal 1. As can be seen it is an isoceles triangle with an altitude substantially equal to its base length. All parts of the assembly are formed from 1/4 inch by 1 inch bar steel. The mounting base 2 has an opening 3 to receive a bolt 4 which together with a nut 5 secures the base 2 to the undersurface 7 of a plank 8. The triangular shape is formed by conventional metal working procedures and the ends of the triangle are joined by weld 9. At the apex 10 a tension strap mounting plate 11 is welded 12 to each side 13 and 14 of the triangle apex. As seen in FIG. 1, the plate 11 has its end portions 15 angled upwardly as seen at 16. For the embodiment described herein, the angle 16 is 7°. Each end portion of plate 11 has an opening 17 to receive a bolt to secure one end of each tension strap 18 and 19 to the plate. As will be noted, a nut 20 for bolts 21 and 22 is positioned over each opening 17 and welded to said plate 11. This arrangement not only facilitates assembly but prevents loss of or misplacing the nut. One end portion 23 and 24 of each tension strap 18 and 19 is deformed at an angle which will place that end portion in surface to surface contact with the undersurface 7 of plank 8. An opening (not shown) in each such end portion receives a carriage bolt 25 and 26 which has been passed through plank 8 and is secured therein by a nut 29 and 28. The opposite end 30 and 31 of each tension strap remains undeformed and has an opening (not visible) through which a bolt 20 or 21 can be passed to secure that end portion to the respective end portion of tension strap mounting plate 11 by engaging with the respective fixed nut 20. The assembled truss in the operative position is clearly shown in FIG. 6. 
     In the particular embodiment shown and described herein, the truss parameters are as follows: the pedestal has a base length of 61/2 inches and an altitude of 61/2 inches; each tension strap is 5 feet in length; and the carriage bolts 25/26 are preferably at least 1/2 inch by 4 inches to protrude below nuts 27/28. The above parameters are suitable for use with plank lengths of 10 to 16 feet. For planks in the 18 to 24 foot range, tension straps would be appropriately lengthened.