Apparatus for checking dimensional and geometrical features of pins

Abstract

An apparatus for checking the diameter and the roundness of pins, for example crankpins and main journals of a crankshaft rotating about its main axis of rotation (), includes a measuring device, coupled to a Vee-shaped reference device () and including a feeler () axially movable along the bisecting line of the Vee, or a direction slightly sloping with respect to it, and a movable support device for the reference Vee. The support device includes a support element () and a coupling mechanism that carries the reference Vee (). The coupling mechanism includes, for example, two support sections (e.g. parallelogram structures) in series and enables plain translation displacements of the reference Vee. While checking an orbitally rotating crankpin, the Vee-shaped device maintains proper contact with the surface of the pin by virtue of the force of gravity, and the angular arrangement of the direction along which the feeler () moves remains substantially unchanged.