GB1146828A - Improvements in and relating to disc grinders - Google Patents

Abstract

1,146,828. Grinding. LANDIS TOOL CO. 27 May, 1966 [28 May, 1965], No. 23766/66. Heading B3D. A disc grinder comprises at least one rotatable abrasive disc and work carrier means for receiving one or more workpieces, moving them successively into operative engagement with the abrasive disc(s) and then discharging them, said work carrier means comprising: (i) a rotatable work carrier having work holders at intervals therearound, (ii) drive means for rotating the carrier, and (iii) control means controlling the drive means to index the work carrier to bring successive ones of the work-holders into operative workgrinding disposition relative to the abrasive disc(s) and to effect oscillatory movement of the work carrier for effecting oscillating of the successive workpieces whilst in operation engagement with the disc(s). A disc grinder has opposed abrasive discs 11, 12. A rotary work carrier 15 comprises a plate 16 provided with work-holders 17 each having a pair of pockets 18 for receiving workpieces W. The carrier 15 is periodically rotated by a motor MTR4 through worm gearing 29, 24 and 21, 20. For oscillating the carrier 15, the worm 21 is movable axially by a piston 37 in a cylinder 36 under control of a valve 54 the member 55 of which can be moved against a spring 56 by a solenoid D. A supply shoot 45 has a gate mechanism 46 for periodically releasing two workpieces W. A guide 48 extends from the shoot 45 to a discharge shoot 47 to retain workpieces in the holders. Each abrasive disc is advanced and retracted by a piston 60 in a cylinder 59 under control of a valve 62A the member 63 of which can be moved against a spring 64 by a solenoid C. Cams 50, adjustably mounted on the carrier 15 co-operate with limit switches 8LS, 11LS; cams 51 adjustably mounted on the carrier cooperate with limit switch 9LS; a cam 52 carried by the carrier co-operate with limit switch 12LS. Operation.-On manually closing start switch 70, motor MTR4 is energized to rotate the carrier 15 clockwise. Rotation continues until cam 50 associated with work-holder B actuates limit switch 11LS thereby (1) de-energizing motor MTR4, (2) actuating gate mechanism 46, the first of the two workpieces released dropping into the second pocket in work-holder C, and (3) energizing solenoid C, advancing the abrasive discs 11, 12 towards the workpieces in workholder A, advance continuing until limit switch 10LS is activated. Just before the carrier 15 reaches its fully indexed position, cam 50 associated with workholder B actuates limit switch 8LS thereby (1) preparing the motor MTR4 for rotation and (2) energizing solenoid D, moving piston 37 to the right, rotating carrier 15 counterclockwise, the second workpiece previously released by the gate mechanism 46 dropping into the first pocket in work-holder C. As a result of the counterclockwise rotation of carrier 15, cam 51 associated with work-holder C opens limit switch 9LS, de-energizing solenoid D, moving piston 37 to the left, rotating carrier 15 clockwise, this rotation continuing until cam 50 again closes limit switch 8LS to reverse the rotation of the carrier. Actuation of limit switch 10LS at the end of advance of abrasive discs 11, 12 energized spark out timer relay 2TR. When the relay 2TR times out solenoid D is de-energized, rotating carrier 15 clockwise until cam 50 closes limit switch 8LS, energizing the motor 4MTR to index the carrier 15. When the carrier 15 rotates for indexing, cam 52 opens limit switch 12LS thereby (1) resetting gate mechanism 46 and (2) de-energizing solenoid C, retracting the abrasive discs 11, 12.