GB724162A - Apparatus for gauging profiles of workpieces - Google Patents

Abstract

724,162. Gauging departure from standard form. HILGER & WATTS, Ltd. Nov. 26. 1953 [Nov. 26, 1952], No. 29992/62. Class 106 (2). Apparatus for gauging profiles of a workpiece (e.g. a turbine blade) comprising a feeler, a work holder, a screen, a master profile which moves in dependence with the feeler as it explores the work, means for bring- ing the master profile into view on the screen, and an index fixed on the screen to show conformity or otherwise of the workpiece with the master profile. In principle, the apparatus consists of two work-contacting members 1, 2, Fig. 1, joined to a frame 4, 6 respectively, on to each of which is held a photographic plate of a master profile 5, 7. A fixed source of light (not shown) projects inverted images 5x, 7x, Fig. 3, of the master profiles onto a screen having a reference circle 9 inscribed on it. The apparatus is suitably adjusted initially so that as the feelers follow the workpiece the projected images of the master profiles move along the fixed circle 9, any deviation from the circle indicating a deviation of the workpiece from the master profile. In the actual apparatus a work holder carriage 17, Fig. 4, slides on a bar 14 pivoted at 15 to a base casting 11, the position of the carriage with respect to the base being determined by a stop 19. A second casting 12 supports the feelers and the optical system housing 13. The front frame 29, Fig. 6, which is joined to the workcontacting piece 34 by a connecting bar 32, supports its photographic plate 35 which has a bar 37 attached to it by four leaf springs 45, 47, 49, the position of the plate relative to the frame being adjusted by three screws 41, 43. By a similar method plate 36 is held on the frame 30. The frames are supported on a carriage 22, Fig. 4, mounted on the front end 21 of the optical housing 13 and rotation of a hand-wheel 28 moves a pivoted sector 24, Fig. 5, linked to the carriage by a bar 23 and causes the carriage to move in a vertical plane. Light from a lamp 68 in a housing 67 is projected through the photographic plates via a condenser 69 and lens 70, and reflected by a mirror 71 on to a screen 72. Specification 652,695 is referred to.