Abstract: A manually operable probe head (10) has a support (12), by which the probe head may be attached to the head of a coordinate measuring machine, a first rotor (14) rotatable about an axis (16) relative to the support (12), and a second rotor (46) rotatable relative to the first rotor about a perpendicular axis (48). The first rotor (14) and second rotor (46) are each rotatable through a plurality of kinematic rest positions, into which they may be axially urged through retraction of a tie bar (90). Location of the first and second rotors when not in their rest positions is achieved by three spring loaded pistons (34) and (72). The pistons (34) and (72) ensure that even when not in their rest positions, the first and second rotors always come to rest adjacent such a position. The second rotor (46) carries a connector (54) for receiving a touch probe (50).

Abstract: A probe head for orientating a probe relative to a head of a coordinate measuring machine, has a support a rotor rotatable relative to the support, and a swivel rotatable relative to the rotor. The rotor and swivel are mounted for rotation through a series of discrete, and repeatable rest positions. The relative orientation of support, rotor and swivel is detected by an indicating mechanism comprising a printed circuit board having a series of electrical conductive elements and a contact arm mounted for rotation over the conductive elements on the circuit board. When the electrical contacts of the contact arm come into register with the conductive elements on the circuit board a pulse is transmitted to a micro-processor which determines the relative orientation of e.g. the support and rotor which is shown on the LCD.