Patent GB-712540-A (GB)
Title: Improvements in or relating to apparatus for inspecting linear-dimensions of work-pieces
Inventor: LOXHAM JOHN
IPC: G01B5/207
Filed: 1951-12-17
Abstract: 712,540. Linear-dimension gauges. SIGMA INSTRUMENT CO., Ltd. March 10, 1953 [Dec. 17, 1951], No. 29549/51. Class 106 (2) A gauging fixture for a turret comparator comprises a displaceable member adapted to cooperate with the actuating means of an indicating device through an adjustable distance-piece, there being a replaceable reference anvil associated with the fixture and a gauging anvil arranged for imparting gauging movements to the displaceable member. The turret comparator essentially comprises an indicating device for cooperating with a plurality of gauging fixtures each with a reference anvil and a moving anvil and severally mounted upon a turret which can be turned relatively to the indicating device to cause any selected one of the fixtures to co-operate therewith, each fixture being devised for measuring a different type of dimension and each adaptable for measuring its particular type of dimension in various work-pieces. Each fixture has a plate 7 carried by a part 5 which together with a part 4 and bolt 6 clamps it in engagement with a dove-tailed rib 2 round the periphery of a turret 1. In a fixture for gauging the external diameter of a work-piece W, the base plate 7 carries a bracket 8, Fig. 1, with a lath spring 9 secured thereto and also to a displaceable member 10 whose movements about the spring 9 as a hinge are limited by an adjustable stop 11. A reference anvil 13 is secured by two screws 15 with a dove-tailed slot engaging a member 14 secured to the base plate 7 and a gauging anvil 12 is carried by the member 10 which carries an adjustable distance piece in the form of a screw 16 with lock-nut 17 and tip 18 for engaging an actuating plunger 3 of an indicating device. The fixture is initially set up by employing a setting master and adjusting the distance piece until a desired indication is given. The fixture may be adapted for gauging a different external diameter by substituting a suitable reference anvil 13. A similar fixture for gauging the internal diameter of a hole in a work-piece comprises a wall 26, Fig. 2, having an aperture 26A, extending upwardly from the base plate 7 and, passing through the aperture 26A, an arm 24 secured to the wall 26 by a lath spring 21. An adjustable stop 23 limits. upward movement of the arm 24. which carries a gauging anvil 25 having a measuring tip 30A. One end of a displaceable member 10A is secured to the top of the wall 26 by a lath spring 20 and the other end is secured to the arm 24 by a reinforced lath spring 20A and also carries an adjustable distance-piece., A spring 22 urges the displaceable member 10A upwardly and the tip 30A downwardly. The distance between the tip 30A and the lath spring 21 is made equal to that between the lath spring 20 and the lath spring 20A so that displacements of the tip 30A are equal to those transmitted to the plunger 3. A disc 27 is releasably secured to the wall 26 and has a centrally extending integral boss 28, both disc 27 and boss 28 being slotted to permit the gauging anvil 25 to enter and the boss 28 having a gauge tip 30 opposite the tip 30A. Another gauging fixture, Fig. 3. has a movable member 10B supported by crossed lath springs 32 from an upstanding wall 33 and formed with a laterally extending arm 31 carrying a variable distance-piece for engaging the plunger 3. A spring 33A urges the member 10B to turn anti-clockwise and an adjustable stop 33B limits movement. A body member with an annular rib 34 fitting against the wall 33 is secured in an aperture formed therein and is formed with a central bore to accommodate a plunger 35 forming part of the gauging anvil. The head 36 of the plunger 35 is intended to contact one end of a work-piece W and a peripheral flange 37 surrounding the head 36 and extending therebeyond is intended to engage a shoulder of the work-piece and thereby act as reference anvil for gauging the length of the work-piece from its end to the shoulder. A similar fixture for gauging the internal depth of a hole in a work-piece has a plunger engaging the bottom of the hole and a rim of a body member engaging the face of the work-piece in which the hole is made As each fixture works with the same indicating device the hinges of the movable members are so arranged that in each case movement of the p:unger in a given direction corresponds to over-size in the dimension gauged.