Abstract: A probe comprises a support casing, a movable arm-set with an arm carrying a feeler and a detection device providing a signal further to contact occurring between the feeler and the workpiece. In order to enable the feeler to perform translation displacements along a longitudinal geometrical axis and rotations about transversal axes, the matching between the support casing and the arm-set is obtained by means of a cone-shaped surface, a spherical surface and a spring urging these surfaces into contact. An annular reference surface of the movable arm-set enters into contact with an annular plane surface of the support casing when a first eccentricity value of the feeler, with respect to the longitudinal geometrical axis, is reached, and when a second eccentricity value is reached the signal of the detection takes a determined value.

Abstract: An apparatus for the automatic and simultaneous checking of holes comprises plug gauge devices (11-16) with gauging heads (70, 71) and elements for coupling to a support. The coupling elements are substantially constituted by parallel shafts (29-32) displacing the gauging heads (70, 71) from a rest position to a measurement position, and vice versa, through rotational displacements automatically controlled by relevant actuation devices (60-65). The angular position of the shafts is detected by transducers (52-55), which are connected to a processing unit (58) also receiving the signals of the gauging heads (70, 71). The plug gauge devices comprise further heads (86-89) coupled to rotatable rods (82, 83) for simultaneously gauging diametral dimensions of a hole (10) communicating with the other holes (4-9) and transversal to them. The apparatus is particularly adapted for checking the holes of a cylinder block of an internal combustion engine.