Abstract: A suspension assembly for attaching wheel assemblies to a frame includes a pair of torsion spring subassemblies adjustably interconnected by a center axle tube to form a unitary axle-like assembly whose torsion spring subassemblies can be adjustably fixed in various desired spaced positions for connection to a selected frame having a particular width. Each torsion spring subassembly includes a torque limiter and further includes an outer tube with a bracket-like mounting member thereon for connecting the outer tube to the side beams on the frame, the bracket member being generally planar in shape and adapted to communicate forces from wheels directly through the torsion spring subassemblies to the frame in a manner that minimizes deformation when the torque limiter engages.

Abstract: A torsion spring cartridge is provided for torsionally absorbing loads on a trailer frame or the like. The torsion spring cartridge is insertable into an axle tube and includes a counter torque hub, a bearing block spaced therefrom, and a torque shaft mounted for oscillating rotational movement in the bearing block with torsion rods operably interconnected between the counter torque hub and the torque shaft. The bearing block and the torque shaft each include over-rotation stops that cooperate to prevent over-rotation of the torque shaft during use. The bearing block supports the inside of the axle tube to prevent distortion of the axle tube profile during over-torquing of the torque shaft during use, and a frame bracket supports the outside of the axle tube and transmits forces from the bearing block and axle tube directly to the trailer frame. The torsion rods have ends with substantially circular cross-sections, and are held in place by brazing.