Patent GB-967659-A (GB)
Title: Improvements in or relating to grinding machines
IPC: B24B49/18
Filed: 1963-08-16
Abstract: 967,659. Grinding. HERBERT LINDNER G.m.b.H. & CO. Aug. 16, 1963 [Sept. 26, 1962], No. 32560/63. Heading B3D. A grinding machine comprises a grinding wheel carriage 5, Fig. 1, for the spindle 6 of a grinding wheel 7, a main infeed spindle 12 co-operating with a feed nut 13 for movement of the carriage towards and away from a workpiece, a trueing tool 28 on a trueing carriage 27 movable with and relative to the grinding wheel carriage, a feed screw 22 for effecting movement of the trueing carriage, and a screw-threaded take-up spindle 14 co-operating with the feed nut 13 and connected with the feed screw to adjust the position of the grinding wheel carriage relative to the workpiece by a distance equal to that by which the trueing tool is moved relative to the grinding wheel carriage during a trueing operation. The main infeed spindle 12 is rotatable by gearing 10, 11 connected to a shaft 9 having a hand wheel 8 whereby the grinding wheel, which may be profiled, is fed towards and from a workpiece 4 to be formed with a thread, the workpiece being axially movable on a carriage 2 by a screw spindle 3. The lefthand end of the spindle 12 has a piston 41 which is movable in a cylinder 42 to advance the grinding wheel to its operative position or retract it to the position shown for a trueing operation. The spindle 12 engages the feed nut 13 which is also engaged by the take-up spindle. The latter is axially located relative to the grinding wheel carriage 5 by collars 16 and can be rotated either by a handle 18 or by a hand wheel 18a on the feed screw 22 which is connected by gearing 20, 21 to the take-up spindle 14 and engages a nut 25 on the trueing slide 27. The trueing tool 28 is adjustably mounted on a further slide 33 which is movable between operative and inoperative positions on the slide 27 by a piston-and-cylinder device 34, 35. In operation, when a trueing operation is to be effected, the piston 41 is moved to retract the grinding wheel from the workpiece and the trueing tool moved to its operative position by the piston 35. Rotation of the handle 18 or hand wheel 18a causes the feed screw 22 to rotate and advance the trueing tool relative to the grinding wheel carriage, and the take-up spindle 14 to rotate and advance the grinding wheel carriage relative to the bed 1 of the machine an equal amount. The take-up spindle and feed screw may be rotated by a pawl-andratchet mechanism 37, 38 operated by a piston- and-cylinder device 39, 40. Backlash is prevented by a weight 26 acting on the carriage 5. In another embodiment, the main infeed spindle 12 and take-up spindle 14 are coaxially arranged and the feed nut is in two parts interconnected by a bridging piece. In a further embodiment, the feed nut is in two parts 13<SP>1</SP>, 13<SP>2</SP>, Fig. 4, interconnected by a projection 13<SP>3</SP> engaging a slot 50, and the take-up spindle 14 and feed shaft 22 comprise oppositely threaded portions on a single shaft. In operation, when the main infeed spindle 12 is rotated by a hand wheel 8 to axially move the part 13<SP>1</SP> of the feed nut, a piston-and-cylinder device 41, 42 maintains the projection 13<SP>3</SP> at one end of the slot 50 so that the part 13<SP>2</SP> of the nut with the grinding wheel carriage 5 follows the movement of the part 13<SP>1</SP>. When the grinding wheel is to be trued, the fluid supply to the device 41, 42 is reversed to move the projection to the other end of the slot 50 and retract the grinding wheel from the workpiece to a trueing position. Rotation of the shaft 14, 22 by the handle 18 then moves the nut 25 and the slide 27 in the direction of the arrow to effect trueing and the part 13<SP>2</SP> of the nut tends to lift the projection from the end of the slot but is prevented by the device 41, 42 so that the grinding wheel carriage moves relative to the part 13<SP>1</SP> of the nut or the bed a distance equal to the movement of the trueing slide relative to the grinding wheel carriage. The bearing for the grinding wheel can be rocked to conform to the helix angle of the thread, the slot 50 being of such a width as to accommodate the rocking of the projection 13<SP>3</SP> on the part 13<SP>2</SP> of the nut which is connected to the bearing part of the grinding wheel carriage.