Patent GB-680579-A (GB)
Title: Improvements in or relating to precision grinding
IPC: B24B5/24
Filed: 1950-04-12
Abstract: 680,579. Grinding. RHODES, C.T. Feb. 12, 1951 [April 12, 1950], No. 9056/50. Class 60. A machine for the precision grinding of an article required to have a tapered circular sectioned part accurately ground in concentricity with another circular sectional part comprises a grinding wheel, a recessed block having a hardened recess adapted to accommodate the second mentioned part with the first mentioned part in contact with said grinding wheel, an angularly adjustable member carrying said block and adjustable about an axis perpendicular to the axis of the grinding wheel, a friction engagement wheel for engaging said second mentioned part and holding it in the recess, means for rotating said friction wheel to rotate said second mentioned part in said recess, means for locking said member in any position of adjustment, co-operating scale and index means one of which moves with said member and indicates the movement thereof against the other, and means for adjusting and fixing in any position of adjustment the position of one of said means to adjust the scale reading for any given position of adjustment of said member. As applied to a machine, for grinding the needles of the valves of diesel engine fuel injection pumps or atomisers and grinding'laps for trueing the seats of such valves, as described in Specification 650,569 and having a work holder 3 angularly adjustable about a vertical axis and carrying a block 4 with a hardened V-recess 5 to receive the shank of the workpiece, the work holder is provided with a radial arm 14 the end of which has an index mark 15 reading against a scale 16 marked in degrees; the scale 16 is adjustable over a small angle, being held by screws 23 passing through arcuate slots in the scale. The position of the arm 14 is determined by an abutment micrometer screw 17 on which is a micrometer head 18 carrying a scale 20, marked in minutes, reading against a mark 21; the head 18 can be adjustably rotated with respect to the screw and locked in any position by a lock nut 19. The arm 14 is pressed against the screw 17 by a second abutment screw 22. The machine is set up by using a taper gauge in the form of a flat metal plate having one edge cylindrically formed at 25 to rest in the V-recess 5 in place of a lap or needle, or alternatively having one edge V-shaped at 24, Fig. 3, to rest against the shank of a lap or needle in the V-recess 5. A micrometer gauge clock 26 is mounted temporarily on a member 27 temporarily attached to the spindle of the grinding wheel 2. The work holder 3 is angularly adjusted until the plain edge of the taper gauge is parallel to the grinding wheel axis, this being tested by adjusting the micrometer gauge clock until its feeler point is in contact with the plain edge of the taper gauge and then moving the work head in a direction parallel to the grinding wheel axis by the longitudinal traversing mechanism, and observing whether the reading of the gauge clock remains constant. The main scale 16 and micrometer head 18 are then adjusted until the scales 16 and 20 jointly read the correct angle; they are then locked and the machine is set up ready for use and can be adjusted by means of the scales to grind any angle within the scale range.