GB551711A - Improvements in or relating to optical apparatus for measuring, gauging, and the like - Google Patents

Abstract

551,711. Optical gauging-apparatus. BATY, J. E. Aug. 25, 1941, No. 11427/42. Divided out of 551,688. [Class 106 (ii)] [Also in Group XX] In optical-projection gauging apparatus, a form gauge having a configuration of the correct shape and size common to work pieces which are otherwise of various sizes is placed in one light beam, a work piece is placed in a parallel light beam, and means is provided for adjusting them transversely to the beams so as to centralize them in relation to the beams ; slip gauges and knife edge may also be arranged to enable other dimensions of the work pieces to be checked. Fig. 1 shows a light source 20, condenser 21, beam-dividing mirrors 22, 23, which may be as described in Specification 551,712,. a reflecting system A, which may be as described in Specification 551,688, and a projection lens 46 producing an image on a screen 47. Screws 25 having various diameters but the same threadform and pitch may be successively placed in one beam and compared with a single-form gauge 54 held throughout in the other beam. Fig. 2 shows centres 57 for supporting the screw, and a boss 55 carrying the form gauge, these being carried by standards on a slide 163 movable on a guideway 165 across the beams. A modification is described in which the screw is held against an adjustable stop. The screw-diameters may be tested by first inserting between the centres a plate having a surface lapped parallel to the centres, and wringing on to it slip gauges and a knife edge sufficient to build up the desired diameter. The apparatus is then adjusted to prbduce coincidence in the screen images of the knife edge and the desired diameter of the form gauge, and the lapped plate &c. is replaced by the screw to be tested. The slip gauges and knife edge may be similarly wrung on to the adjustable stop.