Patent GB-706763-A (GB)
Abstract: 706,763. Gauging departure from standard form. TAYLOR, TAYLOR & HOBSON, Ltd. June 27, 1950 [May 20, 1949], No. 13478/49. Class 106 (2). [Also in Group XXXVIII] Apparatus for determining the roundness and truth of parts wherein detecting means are rotated round the test part which is held stationary, comprises a vertical stand 1, Fig. 1, an inspection table 2 on which the test part 3 is clamped, a feeler member 15, associated with an electric detector device 5, suspended above the part 3 and rotatable through a flexible geared drive from a motor 11, the pick-up output being shown on a meter 9 or taken to a synchronous recorder 16 giving a polar diagram of the profile of the test part 3. The inspection table 2 may be raised or lowered by a screwthreaded member 14 operated by a handle 13. The detector device 5 is assembled to a spindle 7 located in a quill 6, and the housing 8 contains mechanism for centering the quill and spindle relative to the test piece 3 by means of two plates 19, 20, Fig. 2, hinged to an L-shaped bracket 21 and controlled by screws 24, 25, operable by handles 24', 25' respectively. The quill 6 is urged against the plates 19, 20 by a spring- loaded roller 28. A housing 10 contains the drive between the motor 11 and the quill 6, the details of the supports for the spindle 7 being given in Fig. 3 (not shown), a small variable inductance also being contained in the housing 10 for the correction of residual centering errors of the spindle 7. The detector device 5 can slide along the edge of the spindle in a fitting 37 by a T- section bar 50, Fig. 4, for coarse adjustment, the bar 50 having an engraved scale to facilitate the initial setting to the nominal radius of the test piece. The pick-up mechanism comprises an arm 15 bearing against a knife-edge 52, carrying the feeler 53 at its lower end, and attached to an armature 54 at the upper end. The armature co-operates with a coil 55 fixed to a bracket 56, hinged at 58, the further end of the bracket having a fine adjustment device consisting of a fine-threaded screw 60 operated through gears 61, 62, 63 by a reversible motor 64, which adjustment varies the position of the knife-edge 52. The variations in inductance of coil 55 are indicated on the polar recorder 16, which is synchronized with the rotating spindle 7. A device, to be mounted on the work table 2, to provide quick initial centering and gauging of simple, cylindrical specimens comprises a sliding plate 83, Fig. 6, with a V groove 86, with coarse adjustment by handle 87, Fig. 1, and fine adjustment by a spring-loaded handle 97, by the movement of a tongue 84 in a groove 85, the test piece 3 being held against the V groove by a spring lever 95, or a clamp 98. The nominal diameter of the work piece 3 can be determined by the position of a depth bar 88 abutting the work piece, as indicated by an index mark 93 controlled by hinged levers 89, 92. A further device for adjusting the position of the feeler 53 with respect to the inspection piece comprises a rod 104, Fig. 7, through the centre of the spindle 7 butting against a lever 100 linked to the carrier bar 50 by a linkage 101, 103, so that movement of the rod 104 by operation of a screw handle 105 causes lateral movement of the detector device 5. The detector device 5 may alternatively comprise a nozzle separated from the test surface by a small gap, the length of which is measured by the leakage of compressed air escaping through it from the nozzle. Specifications 582,636, 613,102, 621,126, 622,544, [all in Group XXXIV], '694,423, [Group XXXVIII], 706,837 and 706,838, [Group XXIII], are referred to.