other shapes are contemplated as previously described and wherein the longitudinal axis of the bore is arranged transverse to the longitudinal axis of the threaded opening 134 in boss 128 a rib 166 is formed extending outwardly from a central portion of one end 168 of the lower bracket member 124 the rib 166 is adapted to be rotationally received within the opening 170 formed between the spaced apart ribs 136 on the upper bracket member 122 as best shown in fig5 rib 166 includes a through bore 172 which aligns with bore 138 within ribs 136 so as to receive an axle 174 for pivotably attaching the upper and lower bracket members 122 124 together a boss 176 is provided extending outwardly from the other end 178 of the arcuate shaped member 160 the boss 176 has a through opening 180 which may be threaded or unthreaded in assembled relationship the openings 152 180 are aligned with each other so as to accommodate a bolt screw or other attachment means for securing the upper and lower bracket members 122 124 together in fixed assembled relationship it is to be understood that other locking assemblies may be used such as clamps hooks or other fasteners both threaded and non threaded.