WASHER FOR USE IN MINING

摘要

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.