Abstract: An arm 12 for holding a tool-setting probe 14 in a machine tool is rotatable between an operative position and an inoperative position. The operative position is defined by elements 48,52 which form a stop against further rotary motion beyond the operative position. These elements 48,52 are arranged as a kinematic support, so that the operative position is defined in a precisely repeatable manner. Springs 40 urge the elements 48,52 together. When the arm is in the operative position, these springs are stretched by a repeatable amount, so that they provide a repeatable force, in order to increase the precision of the operative position.

Abstract: A measuring probe has a stylus carrier supported on a fixed member in a rest position when no force acts on the stylus, the stylus carrier being deflected from its rest position to produce a signal when an external force is applied to the stylus. The support for the stylus carrier comprises two concentric rings of ball bearings of different pitch circle diameters and arranged that each ball on one of the members contacts two adjacent balls on the other member. An additional annular surface is provided on one of the members and is contacted by each of the balls on the other member. The arrangement provides that the force required to deflect the stylus is substantially equal in all directions of the force, and that the movable member is properly guided during its deflection to the point where a signal is produced.

Abstract: An arm 12 for holding a tool-setting probe 14 in a machine tool is rotatable between an operative position and an inoperative position. The operative position is defined by elements 48,52 which form a stop against further rotary motion beyond the operative position. These elements 48,52 are arranged as a kinematic support, so that the operative position is defined in a precisely repeatable manner. Springs 40 urge the elements 48,52 together. When the arm is in the operative position, these springs are stretched by a repeatable amount, so that they provide a repeatable force, in order to increase the precision of the operative position.

Abstract: A touch probe (10) has a housing (12) and stylus-supporting member (14) biased into a kinematic rest position relative to the housing (12) by a biasing mechanism. The biasing mechanism includes a first helical spring (40) which acts between a movable shuttle (44) and an intermediate member (48). The shuttle (44) is movable within a bore (46) and the position of the shuttle within the bore may be adjusted by the action of an adjusting screw (74). A second helical spring (42) acts between intermediate member (48) and the supporting member (14). The first spring (40) has a low spring rate and is pre-loaded such that the second spring (42), which has a high spring rate, will deflect first upon movement of the shuttle (44) or supporting member (14). Once the pre-load of spring (40) has been overcome the two springs (40,42) co-operate to act as a single spring whose spring rate is the sum of the reciprocals of the spring rates of springs (40,42).