GB970523A - Improvements in or relating to an apparatus for marking the scales of a measuring instrument - Google Patents

Abstract

970, 523. Dividing engines for making calibrations. ALBERT LE BOEUF ET FILS. July 19, 1963 [Aug. 3, 1962], No. 28664/63. Heading G1X. An apparatus for marking the scale of a measuring instrument 4 comprises a rotatable plate 1 on which are placed in respective symmetrical positions, the measuring instrument 4 to be calibrated and its dial 6, means for imparting to the pointer 3 of the instrument 4 successive increments of motion corresponding to successive scale values of the quantity which the instrument is intended to measure, means for bringing the rotation of the plate 1 under control of the pointer, and means 5 for plotting a mark on the scale at the end of the station of the plate corresponding to each of the increments. The instrument 4 is mounted so that the pointer 3 rotates about the same axis as that of the plate 1. The plate carries the marking device 5 and a detection device 2 for the detection of the position of the pointer 3, which device incorporates a light source and photo-electric cell (not shown) with a mirror 14 included in the optical path between these two. The plate 1 is rotated by a motor 11 under control of the device 2, and in use a desired electrical signal is applied to the instrument 4, the plate 1 is rotated by the motor 11 until the light path between the light source and photoelectric cell is interrupted i.e. until the mirror 14 is in line with the pointer 3, when the rotation of the plate is stopped and the marking device 5 is actuated to mark the dial 6. The Specification describes an automatic control circuit for the apparatus in which successive equal electrical voltage increments are applied to the instrument 4, and between each increment, the plate 1 is rotated automatically to detect the position of the pointer 3, and the device 5 is actuated to mark the dial 6 with a line ' of the desired length.