Abstract: The invention provides a modular measurement device 100 having, attachable to the quill 12 of a CMM, any one of a plurality of stylus support modules 120ab, 120cd, or 120ef. Attachable to a stylus support module is a range of stylus modules 110a-f. The stylus support modules have different spring rates to ensure that a near optimum response can be obtained for each stylus module used. The stylus modules may be configured so that each cannot be mistakenly fitted to the wrong stylus support module. The modules are held together by magnetic attraction, and the strength of attraction is cascaded so that the stylus module is removed first if pulled off.

Abstract: A coordinate measuring machine carries a modular touch trigger probe 100, via an adaptor 200, on its movable arm 10. The probe 100 consists of a retaining module 102 which is mounted to the adaptor 200, and a stylus module 104 which is magnetically connected to the retaining module 102 in a manner which enables the exchange of one stylus module 104 for another. The adaptor consists of a pair of coupling members 202,204 which are urged into mutual engagement by magnets 212. Automatic exchange of stylus modules occurs by using movement of the arm 10 to disengage a stylus module 104 from the retaining module 102. Similarly, the exchange of one probe for another is carried out by using movement of the arm 10 to disengage the lower coupling member 204 from the upper coupling member 202.