Patent GB-1290115-A (GB)
IPC: B23B47/18
Filed: 1971-01-11
Abstract: 1290115 Grinding; feed mechanism TOYODA KOKI KK 11 Jan 1971 [22 Jan 1970] 1181/71 Headings B3B and B3D A feed mechanism for controlling a machine tool, such as a grinding machine, for dead stop machining and fine feed machining comprises an operating shaft 31 for connection to the tool, means 3 for rotating the shaft, an operating member 14 carried by a shaft 5 and rotatable with respect to that shaft and movable axially between first and second positions, means 13a for selectively clamping the operating member to the shaft 5 when the member is in either of its positions, dead stop means 19, 21 limiting rotation of the shaft 5 when the operating member is clamped to the shaft in its first position, and fine feed means 26 for rotating the operating member when clamped in its second position The operating shaft 31 carries a feed screw (not shown) for movement of a table 2 relative to a bed 1 and is connected by gears 29, 30 to the shaft 5 keyed to a clutch member 6 which is secured to the boss 4 of a hand wheel 3 and axially movable by a knob 8. A tapered face 6a of the clutch member 6 is engageable with a mating face 20a of a second clutch member 20 which is rotatable on the shaft 5 and formed with a pinion 27 engaging a rack on a rod 28 of a piston-and-cylinder device (34, Fig. 2, not shown). The operating member 14 is rotatably mounted on the clutch member 6 and axially movable between the first and second positions which are determined by a spring pressed ball 17 engaging one or other of grooves 16. The operating member is formed with an annular groove in one face in which a ring 10 is disposed. The ring is carried by a sleeve 9 secured to the boss 4 and is split by a slot 11. A tapered clamp member 13a is axially movable by a knob 12 to expand the ring into clamping engagement with the operating member 14 in either of its two positions. In the rearward position of the operating member, a stop member 19 carried thereby is engageable with a second stop member 21 carried by the clutch member 20, while in the forward position of the operating member, an internal gear 25 secured thereto is engageable with a gear 24 formed in a member 22 which is rotatably mounted on the clutch member 20 and secured to a worm-wheel 23 engaged by a worm rotatable by the fine feed knob 26. In operation, for dead stop machining, the operating member is moved to the position shown and the clutch members 6, 20 disengaged by operation of the knob 8. The operating member is rotated to a position wherein the distance between the stop members corresponds to the desired dead stop machining and is clamped to the feed wheel 3 by actuation of the clamp 13a. Rotation of the feed wheel thus rotates the shafts 5, 31 until the stops 19, 21 engage. For manual fine feed machining, the clamp 13a is released to permit the operating member to be moved to its forward position to disengage the stops and engage the gears 24, 25. Rotation of the hand wheel 3 is transmitted by the clutch member 6 to the shafts 5, 31, the operating member 14 being held against rotation by the gears 24, 25. With the operating member 14 clamped in its forward position by the clamp 13a, further fine feeding is effected by the knob 26 rotating the worm engaged with the wheel 23 rotating the shafts 5, 31 via the gears 24, 25, operating member 14, hand wheel 3 and clutch member 6. When the clutch members 6, 20 are engaged, the piston 28 can be operated to rotate the clutch members 6, 20 and hence shafts 5, 31.