GB782375A - Improvements relating to machinery or apparatus for grinding and polishing articles of metal - Google Patents

Abstract

782,375. Polishing. HOCKLEY CHEMICAL CO., Ltd. April 3, 1956 [Jan. 1, 1955], No. 20/55. Class 60. Means for feeding a bar D, Fig. 1, of polishing material against the periphery of a polishing mop or grinding wheel A comprises a base 10, Figs. 1 and 4, adapted to be appropriately mounted in relation to the mop or wheel, a longitudinal channel 10a in the base for the reception of the bar D, a feed block 15 for the bar slidably mounted on the upper face of the base and having a pawl 20 engaging the rear end of the bar, a feed screw 14 disposed above and parallel to the channel for co-action with a partial nut 16 in the feed block, and poweroperated ratchet-and-pawl means for rotating the feed screw. As shown, the base 10 is mounted on a bracket B<SP>1</SP> projecting from a casing or dust hood B enclosing the mop or wheel A and is adjustable to and from the hood by a screw 43, a clamp 41 being provided for fixing the base in adjusted position. The feed block 15 is slidable longitudinally on the base 10 in guides 10b, Fig. 4, formed at the mouth of the channel 10a, and the partial or half-nut 16 is mounted in the feed block for transverse slidable movement, being urged into engagement with the feed screw by a spring 17 and withdrawable therefrom by a lever 19 when it is desired to adjust the feed block independently of the feed screw. The feed screw, which is rotatable in brackets 11, 12, carries at its outer end a ratchet wheel 21, Figs. 1 and 3, for actuation by one or a pair of spring-urged pawls 22 on an arm 23. This arm is rocked in order to rotate the ratchet wheel and feed screw by a rod 25 which engages a pin on the arm and is pushed against the action of a spring 26 by a disc 27 eccentrically mounted on a spindle 28 driven by an electric motor 29 ; the disc has a diametric slot fitting over the spindle and is arranged to be clamped thereon in its desired eccentric position. A cam plate 34a on the feed block 15 contacts a switch 35 at that point in the feed when the bar D needs replenishing and so operates a warning lamp or other signal ; a second switch 36 is subsequently actuated by the cam plate to stop the feed motor 29 while leaving the warning signal still operating. After withdrawing the feed block 15 rearwardly, a new bar D can be inserted so that it abuts against the end of the remaining portion of the old bar, and the feed block is then again advanced so that the spring-mounted pawl 20 engages the rear end of the new bar. The bar D may be held in the channel 10a by one or more spring-pressed plates 38. If desired, the actuation of the arm 23 for operating the feed screw 14 may be effected by the piston of a compressed air or hydraulic cylinder which is pivoted on the base 10 and is controlled by camoperated valves ; in this case the second switch 36 is dispensed with and the feed of the block 15 is brought to a stop when the half-nut 16 coacts with an unthreaded portion of the feed screw.