Fastener for adjustable support device

Abstract

A fastener, for releasably securing movable panels or other components of a support device, includes a clamping member having a cap and an externally threaded shank, a clamping knob internally threaded for movement along the shank, and a retaining member having a threaded shaft received into an internally threaded aperture of the shank. The external shank threads and internal knob threads have a relatively coarse pitch, while the shaft threads and internal aperture threads have a relatively fine pitch. The clamping knob includes a recess with a locking shoulder that engages a head of the retaining member, thus to determine a locked position for the knob, preventing further movement of the knob in the axial direction away from the cap. The locked position can be set to coincide with a clamping position of the knob, or alternatively spaced apart to allow limited axial travel of the knob. The knob and cap have opposed clamping faces at the outer edges of respective resilient projections that are slightly elastically deformed during clamping, thus to provide an elastic restoring force for a positive hold of the releasably secured components. One of the clamping members, typically the cap, can include a stud or other suitable detent adapted for capture within a slot or against another feature of one of the components, to prevent rotation of that clamping member during fastening.