GB564386A - An instrument for the verification of internal and external diameters - Google Patents

Abstract

564,386. Gauging apparatus. COOKE, TROUGHTON, & SIMMS, Ltd., and TAYLOR, E. W. Dec. 21, 1942, No. 18158. [Class 106 (ii)] An instrument for verifying internal and external diameters, by comparison with reference or master slip gauges, includes two spaced gauge-contacting arms and a levelling vial, one of the said arms being connected to the vial by lever mechanism for converting small relative movements between said arms, into a highly magnified but proportional movement of the air space of the levelling vial. The instrument shown in Figs. 1 and 2 comprises a base 1 with levelling screws 8 and a circular bubble 11. The base is bored to receive a spindle 2 supporting a composite table comprising a cross-piece 13 with rollers 15, a lower table 16 mounted on the rollers, an intermediate table 22 mounted to turn on the table 16, slides 29 secured to the table 22 which support a member 25 forming part of a ball race 31 for an upper table 30 on which the work is supported. The parts are held together by screws 32, 33 and a flange 23. The spindle 2 is raised and lowered by a rack and pinion. A bracket 18 attached to the lower table 16 is forked to embrace an eccentric pin 20 operated by a knurled knob 21 to rock the table 16 about the axis of the rollers 15. Rotation of the intermediate table 22 is effected by a handle 24 and a knurled knob 28 through a rack 26 and pinion 27 moves the upper table 30 in a directon parallel to the axes of the rollers 15. The vertical position of the table is indicated by a scale 34 and index 35. A bracket 36 with an overhanging flange 37 supports the contacting arms 57, 68 and the indicating mechanism. To the flange 37 is attached hardened steel ball tracks 38, 40 supporting a slide 41 for horizontal movement. The slide 41 is controlled by a spring 46 and has attached thereto a bracket 42, Figs. 1 and 4, and a dovetail piece 47. The bracket 42 carries a micrometer screw 43 and reading dials 44, and the dovetail piece 47 carries a plate 48 with an index 52, Fig. 5, co-operating with a scale 53. The contact arm 57 is attached to the plate 48 by a finger screw 56 and may be moved to the left to enable the work to be inserted by a finger knob 94 extending from the bracket 42 on the slide 41. A dovetail piece 60 on the fixed flange 37 carries a plate 61 with an index 64 co-operating with a scale 65 and has. attached thereto the second contacting arm 68. Between the end of the spindle 43 of the micrometer and the end of a needle on a spring-controlled plunger 77 housed in the slide 41 is a hardened steel plate 75 arranged in a pivoted bracket 74 on which is supported a box 81 with a levelling vial 82. Above the vial is window 91 and a hinged mirror 92 for viewing the -air bubble. When not in use the box 81 may be held by a safety screw engaging a hole 90 in the box.