Tension indicating washer unit

Claim 1

A multipiece, preassembled washer unit comprising at least two superimposed, coaxial washer members, means interconnecting the washer members from relative axial movement, the bottommost of said washer members being a cone-like spring device, a ring gauge member interposed between at least the outer marginal regions of the superimposed washer members, the ring gauge comprising a radially extending flange portion retaining the gauge on the unit and adapted to be pinched between the outer marginal regions of the washer members, the gauge further including side wall portions extending generally perpendicularly of the flange to surround and locate the gauge relative to the uppermost of the superimposed washer members, the side wall portions comprising vertical corrugations about the entire periphery consisting of a plurality of V-shaped wall sections with the apices of said sections extending substantially parallel to the axis of the fastener and extending from the uppermost edge of the side wall to the flange the apices of said vertical corrugations being closely spaced from each other and contacting the outer periphery of the uppermost washer thereby providing a means for laterally sizing the gauge on the uppermost washer and for eliminating free lateral movement of the radially extending flange of the gauge relative to said washer, said plurality of V-shaped wall sections being directly interconnected to one another at apices on the outer surface of said wall, said outer surface thus being provided with external grasping means for said gauge, wherein the unit may be associated with a rotary threaded fastener member in such a manner as to simultaneously provide spring take-up capabilities to a fastened joint while providing an indication of the attainment of a predetermined tension level in the joint when the conical spring member has been compressed an amount directly relatable to the predetermined tension level, said indication being the pinching of the ring gauge between the washer members to restrain the gauge from free rotation relative to the washer members.