An analogue probe 100 includes a fixed structure 110 and a stylus supporting member 112 suspended relative to the fixed structure 110 by three serially connected pairs of leaf springs 114,116,118. Displacement of the supporting member 112 relative to the fixed structure 110 is transduced by three opto-electronic scale and readhead transducers 136,144;138,146;140,148. The distorting effect of bending moments applied to the tip 130 of the stylus 128 upon leaf springs 114,118 is counteracted by an increased spacing between upper ends of leaf springs of a given pair, relative to the spacing between leaf springs at their lower ends; the resulting arrangement forming a trapezium as opposed to a rectangle. This enables longer styli to be employed before distortion of the leaf springs causes failure of the opto-electronic transducers due to unwanted tilting of the supporting member 112.
RELATED APPLICATIONS
This application is a Continuation-in-Part of Ser. No. 08/034,770, filed on Mar. 19th, 1993, pending which in turn was a continuation-in-part of Ser. No. 07/643,373, filed on Jan. 21st, 1991, now U.S. Pat. No. 5,212,873.
A stylus has a detection element support part 1E for supporting and fixing piezoelectric elements 21 to 24 and a rod 1D placed on the detection element support part 1E. The detection element support part 1E has a plurality of flange parts 1F each being regular polygonal in cross section orthogonal to the axis of the rod 1D. The displacement detection elements are attached to the sides of the flange parts 1F in a state in which they are inclined at a predetermined angle .alpha. relative to the axis of the rod 1D. If a measured force in a torsion direction Q or in a bend direction P occurs on the rod 1D through a contact ball 1A, the measured force is transmitted along substantially the length direction of the piezoelectric elements 21 to 24.
A probe 8 comprises a housing 10 and a member 20 movable with respect to the housing onto which a stylus 12 may be mounted such that movement of the stylus results in movement of the member and a primary transducer 50, 52 for measuring movement of the member relative to the housing. The member may be located in a precisely defined rest position 22, 24 with respect to the housing, putting the probe in a mechanical datum position. For a combined transducer probe, this enables the primary transducer 52, 54 to be locked while enabling use of a secondary transducer 70. The primary transducer outputs can be datumed while in this mechanical datum position. Drive 40, 50, 60 or bias 26 means in one axis secure the member in its rest position in all axes.
An apparatus for detecting position change information of an object includes a contact member for contacting the object, and a detecting unit for obtaining position change information of the object by detecting a change in force applied from the object to the contact member.
A measuring probe includes a suspension module 112 in which a stylus holder 140 is suspended from a housing on a pair of diaphragms 142,144. At least one of the diaphragms is formed with spiral cut-outs whereby the stylus, which is connected at the center of the diaphragms, is able to move transversely of the axis of the housing as the stylus holder pivots when transverse forces are applied to the stylus tip. A transducer module 110 is releasably supported on the suspension module by a kinematic mounting 116,118 and is retained in position by magnets 120. The transducer module contains optical transducers 200,210,220 for measuring the deflection of the stylus.
