GB555365A - Improvements in or relating to apparatus for examining helices - Google Patents

Abstract

555,365. Screw gauges. BATY, J. E. April 21, 1942, No. 5317. [Class 106 (ii)] Apparatus for examining articles having helices such as screw-threads comprises a pair of spaced gauging members, one of which comprises a grooved roller and the other comprises a flat anvil or plate having a series of grooves of constant depth in a common plane and at least a quarter of an inch long and at least as long as the smallest diameter of the grooves of the roller member, which grooves are adapted to be engaged by the helices to be examined so that the article can be rolled in the grooves to bring its appropriate contacting points past the corresponding points of the roller member, each of said members being adapted to contact the appropriate internal shape of the helices, and at least one of said members being rotatably adjustable about an axis passing through both said members. A horizontal grooved anvil 8 is removably secured to a block 16 rotatably adjustable on a base 7 according to the helix angle an angular scale being marked on the block 16. A roller 15 with annular or helical ribs is supported in a yoke 53 by plate springs 56, 57 which permit slight endwise movement of the roller to ensure engagement with the thread of the test-piece. The yoke 53, which may be interchangeable according to the screw-thread being tested, is carried by blocks 48, 49, 50 supported by two leaf springs 40, 41 from a block 25 which is adjusted until vertical on a bracket 11 adjustable vertically on a standard 9. Block 48 carries a ball engaging rod 60 of a dial gauge 14, also adjustable vertically, which indicates variation from standard of the diameter of the screw. The method of setting the gauge is shown in Fig. 4, standard wires 65, 66, 68 being placed in the grooves and slip gauges 67 being placed between the jaws.