Abstract: A device for precisely measuring the depths of cuts of a Mercedes Benz key at the critical depth locations which determine the unique characteristics of each such key. In a first embodiment for measuring a single shelf key, the key is measured by a projecting probe of a circular gauge, by moving the key via a slide plate. The slide plate is incremented by a rack-and-pinion arrangement, the rack forming part of one side edge surface of the slide plate. A stop member cooperates with cut-outs formed in the other side edge surface of the slide plate for holding the slide plate, and therefore the key, at each of the critical locations where depth of cut is to be measured. In the second embodiment, a double shelf key may be measured by the use of a pair of oppositely disposed and aligned probe tips of a pair of circular measuring gauges.

Abstract: A device is disclosed for cutting a portion of a patella during knee surgery in which the articular surface of the patella along with a portion of the bone of the patella is cut away for implantation of a prosthesis. The device disclosed provides a fixed clamping member and an adjustable clamping member which clamp the patella and space from the patella a support surface for an oscillating saw used in the cutting of the patella. The precise plane of cut is provided by the use of a placement aid which is used according to the method of the present invention. The placement aid positions the support surface a precise depth below the articular surface of the patella during the clamping procedure, which clamping procedure also horizontally levels the support surface and the device so that all cuts through the patella are made in a perfectly horizontal plane.