Variable torque-rate test joint

Abstract

A variable torque-rate test point for the performance testing of rotary tools for threaded fasteners comprises a screw-threaded bolt (1) having a moment of inertia comparable to that of a bolt to be tightened using the rotary tool. The bolt (1) is tightened in the test joint against a torque-rate adjustment device (6) which can be adjusted to simulate a hard or a soft joint. The adjustment device (6) comprises a washer portion (7) beneath the bolt head (4), at least one spring beam (8) extending from a reaction point (9) radially outwardly of the bolt (1), and a pivotal bearing member (10) or other pivot at a mid portion of the beam (8). The beam (8) flexes as it extends in cantilever over the pivot point, and that flexure can be adjusted to vary the torque-rate of the test joint by varying the distance between the pivot point and the rotary axis of the bolt (1).

Dependencies are inferred from the claim text.