Abstract: A crane, and a boom assembly for a crane, include an outermost boom portion having the area between its front chord members being substantially open. Inner lacing members extend in intersecting pairs between diagonally opposing pairs of chord members for strengthening the boom. The various lacing members in the latticework construction for a crane are connected to the chord members using reusable clevis pin assemblies of a predetermined tolerance. This enables it to be easily assembled and to be readily disassembled for ease of transport and storage in a compact state. It also produces a rigid structure having substantially no internal residual stress.

Abstract: A suspension arrangement for a heavy crawler vehicle having plural supporting rollers which are constructed and mounted on elastomeric pad devices such that the overall loading characteristic of the pads is non-linear and terminates in a bulk modulus compression range. The roller assemblies and pad devices are disposed in cavities in free sliding contact with the cavity walls. The rollers and elastomeric pad devices are so constructed as to facilitate relative vertical movement of the rollers under load along the sideframe to enable the vehicle to operate on uneven surfaces with superior load distribution between the totality of load-supporting rollers. The present invention also includes a crawler vehicle having tracks mounted for rolling action in either parallel or converging planes, depending on the contour of the road surface. The present invention also contemplates roller units mounted for lateral rocking movement, and also four roller units.