Abstract: A device for measuring and/or checking the diameter of a cylindrical part (2) moving orbitally about an axis (3) during a grinding process. The device comprises a measuring head (7) coupled to a holder (18, 22) which is provided with a member (26) for engaging the circumference of the part (2), and is movably mounted in a direction parallel to itself on a frame (31) so that it can follow the orbital motion of the part (2). Grinding is performed by means of a tool (1) moving transversely to said axis (3), and the frame (31) is moved transversely to said axis and synchronised with the motion of the tool (1).

Abstract: This measuring arrangement (1) enables the self-calibration of cylindrical parts (2) in the course of machining and interrupts such machining when a predetermined dimension has been attained. It comprises a head (5) exhibiting a V opening bearing on the part to be measured (2) and a pneumatic sensor (10) associated therewith. The system includes coupling means (25, 26, 27, 29, 31, 32), urging means (33, 34) and sustaining means (39) for the head in order to assure a permanent contact between the part to be measured and contact pieces (8, 9) carried on the V opening. The arrangement offers a very small thickness so that it may attain narrow and deep zones as for example those of cylindrical crankshaft bearings.

Abstract: The body (2) of the tool-holder (1) is equipped with spherical caps (14, 15, 16) which come to rest against the flat inside faces (6, 7, 8) of a trirectangular trihedron in the tool-mounting base. Flanges (17, 18) guide conical-tipped retaining pins (21, 22) in apertures (20, 21). These tips fit into conical recesses (23, 24). The rod (13) of a jack mounted on the base spreads the pins apart, and while entering the recesses, the pins exert on the tool-holder a force capable of immobilizing it and acting along a predetermined line of action.