BREAK AWAY SLIDE MECHANISM WITH ENHANCED POSITIONING ACCURACY

摘要

An actuator for selectively extending and retracting a probe in a measuring instrument comprises an actuator body, a carriage having a first aperture slidably attached to the body, and a second aperture receiving a probe holder having a probe. The first aperture of the carriage, which surrounds the actuator body, includes a first plurality of magnets disposed around an inner circumference of the aperture. The actuator body includes a lead screw, a round lead screw nut mated with the lead screw, and a second plurality of magnets arranged on a periphery of the lead screw nut, generally aligned with the first plurality of magnets. The magnets are arranged so that the carriage may be displaced with respect to the actuator body a sufficient amount that the magnets do not significantly restrain the further movement of the carriage.