GB1495202A - Grinding machine - Google Patents

Abstract

1495202 Sharpening saws and cutters AUTOMATIC GRINDING MACHINE & ENG CO Ltd 26 Aug 1976 [27 May 1975 23 Oet 1975] 23111/75 Heading B3D A grinding machine comprises means 24 for supporting a circular saw or milling cutter for rotation about its own axis, cyclically controlled clamping means 42 for successively clamping and releasing a saw mounted on the machine at least in a zone of the saw adjacent to a grinding position, cyclically controlled indexing means 56 for the saw, a cyclically controlled grinding wheel mounting 98 adapted to move into and out of an operative position, and control means arranged so that the clamping means is released to allow the indexing means to index the saw but applied during movement of the grinding wheel mounting through the operative position. The machine has a column 12 which is upstanding from a base 10 and, on one side, carries the support for the saw and, on the other side, the support for the grinding wheel. The support for the saw consists of a bracket 18 housing a vertically adjustable ram 20 carrying a twoarmed work-table 22, one arm of which is slotted to receive a T-bolt arrangement 24 for mounting the saw thereon in a manner similar to that described in Specification 1,424,927. The upper end of the ram 20 is slightly inclined to the horizontal and adjustment of a tapered washer 26 between the ram and work-table effects a tilting adjustment of the work-table for effecting relief grinding of the saw teeth. A pad 36 is secured to the junction of the two arms of the work-table to engage the lower surface of the saw, the saw being releasably clamped against the pad by a second pad 42 on a rod 40 which is slidable in a sleeve 38 by action of a pneumatic cylinder-and-piston device 44 which is slightly spring loaded to hold the pad 42 against the saw but allow it to rotate about its axis during indexing but can be actuated so that the pad holds the saw against movement during grinding thereof. The device 44 is mounted on the sleeve 38 which is secured to an upper part 32 of the other arm of the work-table and also supports the indexing means. A linear and rotary bearing 48 is mounted on sleeve 38 and angularly adjustably supports two brackets 50, 52. The bracket 50 has an arm 54 from which depends a finger 56 for engaging the space between successive teeth of the saw. A second arm 58 extends from the bracket 50 and carries a stop 60 for engagement with a fixed stop 62 secured to the upper part 32 of the said other arms of the. work-table. The frame stop is stopped so that when the bracket 50 is raised, further movement of the bracket can be effected, the vertical movement of the bracket 50 being produced by a pneumatic lifting cylinder 66. The upper bracket 52 has a radial arm 20 pivotally connected to the ram of a pneumatic indexing cylinder 72 connected to the part 32. The indexing stroke length is determined by setting the starting position of the finger 56 by angularly adjusting a bracket 76 about the sleeve 38 for engagement with a post 78 on the upper bracket 52. The cylinders 44, 66, 72, are cyclically controlled by a pneumatic supply system such that with the indexing ram 72 retracted and the lifting ram 66 retracted, the finger 56 engages a space between the teeth of the saw which is turnable about its axis as the clamping cylinder 44 is not actuated. The indexing cylinder is actuated so that the saw is indexed until the stops 60, 62 engage whereupon cylinder 44 is effective to clamp the saw. Lifting cylinder 66 is then actuated to raise the finger 56 from engagement with the saw and to lift the stop 60 so that the indexing cylinder moves to engage the second part 64 of the fixed stop so that the finger 56 is clear of the grinding zone. After grinding, cylinder 72 returns the finger 56 to its starting position, and the cylinders 44, 66 release the clamping pressure and lower the finger 56 into the succeeding space for the next indexing operation. The support for the grinding assembly consists of a vertical ram 80 which is angularly adjustable on a bracket 52 on the column 12 and carries an arm 84 having a pair of bosses 86 mounting linear and rotary bearings 88 for a feed spindle 90. A bracket 92 supports the spindle of the grinding wheel 16 which is belt driven 98 from a motor 96 mounted on a bracket 94 on the spindle. A pneumatic feed ram 100 is secured to the arms 84 and to a bracket 102 fixed to the spindle to effect feed movement of the grinding wheel towards and away from the saw, an hydraulic check ram 104 controlling the in-feed speed of the wheel during the actual grinding operation. The grinding wheel can be tilted between alternative positions on alternate in-feed strokes so that the tops of alternate teeth are raked on alternate sides by operation of a cylinder device 106 which is connected between the arm 84 and one of a pair of brackets 108 clamped to the spindle 90, each bracket having an adjustable stop 110 co-operating with a fixed stop 112 on the bracket 102. The feed and tilting cylinders 100, 106 are controlled by the circuit controlling the clamping. lifting and indexing cylinders 44, 66, 72. In modifications, tilting of the work-table is effected by adjustment of the bracket 18 on the column, the saw is mounted on an extension arm 124 connected to the work-table to accommodate larger or smaller diameter saws, and the cylinders 44, 66, 72 may be hydraulically operated.