Abstract: A stackable, recessed, locking, insulated thumbscrew for connecting modules together in a stack such that removal of one module from the stack does not loosen other modules in the stack has an insulated knurled cap that fits over the end of a main screw body. The main screw body has an interior threaded end and an exterior threaded end, with the knurled cap slidable over the interior threaded end by means of a bayonet pin on the main screw body and corresponding bayonet slot in the knurled cap. A cap spring is captured between a retainer flange integral with or retainer ring mounted on the interior threaded end adjacent the exterior threaded end and the knurled cap to apply pressure to the knurled cap. In a raised position the knurled cap may be readily grasped for manual screwing and unscrewing of the thumbscrew to add or remove a module from the stack.

Abstract: An instrument housing defines a chamber and has a metal shell with an aperture region defining an array of parallel elongated apertures. The shell has an elongated web between each pair of adjacent apertures, and a raised element protrudes from the web. The raised element is spaced apart from each aperture to reveal a portion of the web near each aperture. A resilient, electrically conductive spring element is electrically connected to the web and has a compressible portion extending away from the web, such that a metal plate pressed toward the revealed surface makes electrical contact with the spring and thereby to the shell, and is laterally constrained by the raised element. The raised element may be welded to the web with the spring captured between, or the raised element may be partially sheared to protrude from the web, with an aperture in the spring closely receiving the raised portion with an interference fit.