Patent GB-1460560-A (GB)
Title: Centreless grinding machine
IPC: B24B5/18
Filed: 1975-09-18
Abstract: 1460560 Centreless grinding WERKZEUGMASCHINENKOMBINAT 7 OKTOBER VEB 18 Sept 1975 [23 Sept 1974] 38358/75 Heading B3D A centreless grinding machine for the external plunge grinding of circular crosssection workpieces 21 comprises a grinding wheel 2 on a fixed grinding spindle mounting 1, an intermediate carriage 17 carrying a support rail 22, and a further carriage 9 carrying a regulating element 11, the plunge-grinding movement being transmitted from a device 5 on a swivel carriage 4 on the machine frame 1 through the further carriage on to the intermediate carriage, the device also effecting a relative movement of the further carriage and intermediate carriage so as to effect a spacing apart of the support rail and regulating element so that a workpiece, after being ground, can drop therebetween, both movements being effected by a common piston rod 8 of the device, a swivel piston and cylinder 6, 12 on the main frame or carriage 4 having a piston-rod part 16 of different diameter to a part 15 and connected to the intermediate carriage, and an adjustable stop 18 and an abutment 20 acting between the intermediate and further carriages 17, 9. The spindle of the grinding wheel 2 is mounted in the main frame 1 which has a vertical pivot 3 about which the carriage 4 is pivotably adjustable. The intermediate carriage 17 carrying the support rail 22 for the workpiece 21 is slidable on the carriage 4 and slidably supports the further carriage 9 carrying the regulating wheel 11. The device 5 consists of a cylinder which is mounted on the frame 1 or pivotable carriage 4 and has a piston 26 connected to a rod 8 engaging a nut 10 in the further carriage 9, the nut being adjustable along the rod by rotation of a worm 12. The cylinder 6 is also mounted on the frame 1 or carriage 4 and has a piston 27 having a rod part 16 connected to the intermediate carriage 17 and a rod part 15 of larger diameter than the part 16. The fluid supply to the cylinders 5, 6 is controlled by valves 7, 13, 28. The adjustable stop consists of a screw 18 in a member 19 secured to the intermediate carriage 17, the screw co-operating with an abutment 20 on the further carriage. In operation and with a workpiece 21 on the support rail 22, the valves 13 and 28 are switched to the left so that differential pressure acting on piston 27 engages the stop screw 18 with the abutment 20. Plunge grinding is initiated by moving valve 7 to the left to advance the carriages 9, 17, the piston 27 being caused also to advance with carriage 17, excess fluid from the cylinder 6 being discharged through a valve 24. The grinding may be effected at different speeds and, after spark-out, the valves 13 and 28 are switched to the right to hold piston 27 in its instantaneous position. After a short delay, valve 7 is switched to the right to operate the device 5 so as to withdraw the further carriage 9 and regulating wheel 11 and permit the workpiece to drop from the grinding zone between the support rail and the regulating wheel. Thereafter, the valves 13 and 28 are switched back to the left to reposition the carriages 9, 17 as determined by the stop screw 18 and abutment 20.