Abstract: The washer is of frusto-conical shape as viewed externally and consits of a body (21) and a tapered flange (23) depending therefrom. When the lip (28) of the flange rests on a flat surface and the washer is subjected to a predetermined compressive load (26) the tapering of the flange leads to its deformation radially outward. This expansion acts as a visual indication that the predetermined load has been applied. The flattening of the flange which also accompanies its deformation increases the contact area of the washer with the underlying surface and thereby reduces contact stresses. When used in rockbolting, hole (22) receives a rock bolt and the void defined by the flange (23) can accommodate a raised portion of a load plate. The recess (30) receives a bearing assembly or a domed element (the latter compensates for misalignment of the bolt with the surface) so as to transmit tightening loads from the nut of the rock bolt to the washer, etc.

Abstract: A metal door frame assembly comprising two jambs and a lintel, all of the same crosssectional shape, which includes a central door striker portion flanked on its two sides by an inner web and an outer web respectively, each web terminating in a respective end flange which itself terminates in a inturn flange, each inturn flange terminating in an returned flange. Assembly of the jambs and lintel is effected by mitre joints, and at each mitre joint there is a bridging strip which extends between the facing surfaces of the end flanges, and which bears against the rear surfaces of the inner and outer webs of the jamb and lintel. The bridging strip is retained in position by a pair of locking plates, each of which has a pair of tabs which engage respective apertures in the returned flanges of the jamb and lintel.