GB693023A - - Google Patents

Abstract

693,023. Surface and outline gauges. POWER JETS (RESEARCH & DEVELOPMENT), Ltd. Feb. 28, 1952 [March 1, 1951], No. 6036/51. Class 106 (ii). A gauge for detecting distortion of an object comprises a base member providing a reference surface, supports for holding the object in a determined position relatively to the reference surface and a marked transparent screen mounted on that surface, the marking on the screen corresponding to some adjacent part of the said object. As described for gauging an unmachined cast turbine blade, the device comprises a base-plate 1 whose upper face forms a reference surface and which carries four pins 2, 3, 4, 5 for supporting and locating a blade 6 having a root platform 7 and root 8. Each pin 2, 3 has its upper edge stepped and the horizontal face of the step rounded to provide a point support for the leading edge of the blade. The pin 5 lies between but out of line with the pins 2, 3 and it is ball-ended to give point support to the blade toward its trailing edge. The pin 4 has a flattened surface which engages the root platform 7 to locate the blade axially without supporting it. The blade is held in position on the pins 2, 3, 5 by a lightly-spring-loaded finger 9, carried on a forked pillar 10, which can be moved over a dead centre from the position shown in dotted lines where the blade can be inserted, to the position shown in full line, where the blade is clamped. A carrier 14 slides transversely between guides 12, 13 and carries a transparent screen 15 upon which is marked the outline of the end face of the blade root 8. If the blade root is of uniform cross-section, the other end face can be checked with the same screen by reversing the screen and sliding it into the groove from the other end.