Patent GB-845753-A (GB)
Title: Improvements in or relating to machines for checking a plurality of dimensions of a workpiece
Inventor: MAGER ANTHONY JOHN
IPC: G01B5/20
Filed: 1956-04-06
Abstract: 845,753. Gauging-apparatus. SIGMA INSTRUMENT CO. Ltd. April 4, 1957 [April 6, 1956], No. 10607/56. Class 106 (2). A machine for checking a number of dimensions of a workpiece 34 comprises a plurality of gauges each including a gauge-head 52 and an associated indicating device 4, a supporting-member 20 carrying the gauge-heads 52, measuring tips 36, 37, 38, cooperating with the workpiece 34, means 48 for transmitting motion from each tip to an associated gauge-head 52, an adaptor 21 on which the transmitting means 48 and measuring tips 36, 37, 38 are mounted and a connection 126 for securing the adaptor 21 to the supporting member 20 so that the adaptor 21 can be replaced by another, the gauge heads 52 remaining fixed to the machine during such replacement. Fig. 1 shows a front elevation of the apparatus and Fig. 2 is a central crosssection. As shown for gauging a turbine or compressor blade 34, a base 1 carries a horizontally moving slide 16 to which is fitted a frame 19, and a vertically-moving slide 7 to which is fitted a frame 20. Five carriers 25 are suspended by springs 26 from an adaptor-plate 21 secured to the slide 7, and these give five gauging positions along the blade 34, see Fig. 1, at each of which a series of measurements are made. To set up the apparatus slides 7 and 16 are moved by pneumatic or mechanical means from the positions shown in Fig. 2 to allow suitable adaptor plates 21, 22 to be fitted and the blade 34 to be inserted in a holder 33 on the plate 22. The slides 7, 16 are then returned to the operative position shown and gauging takes place. Fig. 2 shows the apparatus for gauging the trailing edge thickness of the blade 34. A lever 44 is pivoted at 45 to the carrier 25 and carries a measuring-tip 38 which acts perpendicularly to the surface of the blade 34 (pivot 45 being on the tangent to the surface at the point of contact). Movement of this tip 38 is transmitted to the movable anvil 51 of a gauge-head 52 (such as described in Specification 724,228) by a pin 48 sliding in the carrier 25. The plate 22 supports, by means of springs 31, a carrier 30 to which is pivoted at 56 a lever 55 carrying a second measuring-tip 41, also acting perpendicularly to the surface of the blade 34. The movement of the tip 41 is transmitted, by a pin 58 sliding in the carrier 30, to a platen 59, supported from the frame 19 by springs 65, and thence by an arm 67 to the body of the gauge head 52 which is supported by springs 70 from the frame 20. Thus an indication of the thickness is given on one of a plurality of tubes 4 by the operation of a gauge, similar to that described in Specification 724,205, connected to the head 52. Similar measuring-tips 36, 37, 39, 40 measure the thickness of other points of the blade 34, and various other measurements such as the chordal width are made. These are also made at each of the five gauging positions mentioned above. Also described is a means for measuring the radial bow of the blade. The adaptor plates 21, 22 are releasably secured to the frames 19, 20, by means of screws 126, 131, respectively, and may thus be replaced by similar plates having carriers 25, 30, levers 44, 45, and measuring-tips suitable for another form of workpiece. Specifications 775,043, 780,871 and 801,542 are referred to.