Compressible washer for visual indication of screw-fastener tension - has annular disc surrounded by metal ring carrying projections for penetrating disc to indicate calibrated tension

摘要

The compressible washer (1) for screw fasteners is constructed to indicate the tensile stress on tightening of the washer. The washer (1) comprises an annular disc (6) having holes (8) spaced on a pitch circle close to its periphery. The washer is enclosed by a metal ring (12) which carries projections (2) on the same pitch circle. The projections (2) have a larger diameter than the holes (8), have a taper lead-in (11) and are of harder material than the disc (6). On tightening the nut (5), the washer (1) is compressed against the surface (3) and the projections (2) penetrate the holes (8) until contacted by the nut (5), indicating the attainment of calibrated bolt tension. USE/ADVANTAGE - Provides clear visual indication of reading required tension. Colour-coded washers enable ready identification of washer calibration within range of available tensions.