Analogue probe

摘要

An analogue probe (100) has a fixed structure (110) and a feeler (stylus) holder (112) which is suspended relative to the fixed structure (110) by three serially connected pairs of leaf springs (114, 116, 118). A displacement of the holder (112) relative to the fixed structure (110) is converted by three optoelectronic scale and reading head transducers (136, 144; 138, 146; 140, 148). The distorting effect of bending moments, applied to the tip (130) of the feeler (128), on the leaf springs (114, 118) is counteracted by an increased spacing between the upper ends of the leaf springs of a given pair relative to the spacing between the leaf springs at their lower ends. The resulting arrangement forms a trapeze in contrast to a rectangle. This renders it possible to use longer feelers before a distortion of the leaf springs causes a failure of the optoelectronic transducers due to undesired tilting of the holder (112). <IMAGE>