JPS6444801A - Touch probe - Google Patents

Abstract

PURPOSE:To obtain a device of high reliability by a method wherein a differential transformer and a parallel spring are adopted, a magnetic substance and a magnet are disposed between the parallel spring and a contact and the displacement of the contact is detected by the differential transformer. CONSTITUTION:A touch probe is moved laterally in relation to a substance to be measured, together with a mounting plate 7. When a contact 1 in the fore end of a shaft 2 contacts with the substance to be measured, the shaft 2 turns around a supporting point 2A. Then the movement of the contact 1 is propagated to the core 3A of a differential transformer 3 and the position of the substance to be measured is converted into an electric signal. A parallel spring 4 having springs 4A and 4B is provided with magnetic substances 5A and 5B on the contact 1 side of the shaft 2. Moreover magnets 6A and 6B are provided on the shaft 2 and the mounting plate 7 respectively so that they attract the magnetic substances 5A and 5B respectively, and thereby the core 3A is made to maintain a neutral position and to have a coercive force. When the magnet and the magnetic substance in either pair are detached from each other by the movement of the contact 1 and the coercive force is lost, a force applied to the shaft 2 and consequently the flexure thereof become small.