Patent GB-641675-A (GB)
Title: Grinding machine
IPC: B24B27/00
Filed: 1947-11-27
Abstract: 641,675. Grinding-machines. REISHAUER-WERKZEUGE AKT.-GES. Nov. 27, 1947, No. 31473. Convention date, Dec. 5, 1946. [Class 60] [Also in Group XXIX] A machine for the selective grinding of bores, threads and plane surfaces comprises a turret head adapted to be fixed in different positions and carrying a number of grinding spindles corresponding to the various grinding operations, the grinding spindle to be brought into operation being coupled with an axially-movable drive spindle displaceable to and from the coupled position. Indexing of the turret.-The turret carries a number of tool spindles, each of which has a clutch member 5711, Fig. 18, - which is engaged with a clutch member on a drive spindle 57 when the tool spindle has been brought to the operative position by rotating the turret on its pin 59. The turret is locked in the correct position by an axially-displaceable pin 731 which is spring-biassed into engagement with one of a number of recesses in the turret corresponding to the indexed positions. The clutch 5711 is disengaged by withdrawing the drive spindle axially by means of a rack and a pinion 7811. The latter is secured to the lower end of a rod 78 to which is pivotally connected a handle 83, Fig. 22, provided with a cam 8211, which, when the handle is horizontal, depresses a spring- loaded sleeve 84 into contact with the drive spindle 57 or its housing to secure the latter against axial movement. The drive spindle is released when the handle is swung upwardly about its pivot and may be displaced axially by rotating the shaft 78. To ensure that the clutch is not engaged before the turret is locked, the drive spindle supports a plate 75 in sliding engagement with the shank of the pin 731 which terminates in a head 76 so that the axial displacements of the pin and drive spindle are related. The drive spindle is rotated by an electric motor 51, Fig. 17, through a belt 55 and is mounted in a support 50. Mounting and adjustment of the turret.- The support 50 is bolted to a cradle 48 which is angularly adjustable with respect to a slide 47. A toothed segment 4811 on the cradle meshes with a rack cut in a piston 89 slidably disposed in a bore in the slide 47; this bore is provided with a hydraulic circuit and provided at each end with an adjustable screw 92, 93 to enable the movement of the piston and therefore the inclination of the cradle 48 to be determined in accordance with the helix angle of the thread. in screw-thread grinding. The slide 47 is transversable on guideways 45, 46 by means of a screw and nut mechanism and a hand wheel 98, Fig. 2. Headstock mounting.-The headstock spindle 8, Fig. 4, .is rotatablysupported in the headstock 5 which is secured to a slide 2 traversable on guideways in a direction perpendicular to that of the slide 47. Traverse for screw threading is effected by a lead screw 115 driven through an interchangeable gear train from a worm wheel 126 which is driven from the spindle 8 through a shaft 39 Fig. 3. provided with a hydraulically actuated clutch 1472. The lead screw is in engagement with a slidable member 110 which is coupled with a piston 104 through a double rack and pinion drive, the cylinder 103 containing the piston being connected with the hydraulic circuit. In an alternative construction, the piston is provided with an extended rod to engage the lead screw, the rack and pinion drive being dispensed with. The spindle 8 has a clamping ring 10 to secure the work. Headstock spindle drive and work traverse.-The shaft 39 is extended as a telescopic shaft 38 driven through a gear box from an electric motor 11. The gear box provides a normal drive at working speed and a rapid drive in the opposite direction in addition to a neutral position in: which the motor .is disconnected from-the drive. Gear changes are effected by a piston 206 contained in a cylinder also connected with the hydraulic circuit. Springs are interposed between each end of the cylinder and the piston so that the latter tends to adopt a central position in which it is retained by a hydraulically-operated spring-loaded lock 239. Stop and reversing means.-The member 110 has an abutment 1141, Fig. 4, to cooperate with stops 243, 244 adjustably secured to the sides of a square drum 130 which is journalled in the frame of the machine and coupled by worms and worm wheels and a shaft 142 with a similar drum 131, Fig. 2, and a hand-control. Rotation of this control turns the drums through intervals of 90 degrees to bring other combinations of pre-set stops into operation. The stops on the drum 131 are arranged to be brought into operation in pairs to cooperate with two spring-loaded plungers 180, 181, Fig. 25a, on the slide 2 so that as the latter reciprocates the plungers are alternately displaced against their springs. by the stops. These displacements energize two magnets 164, 165, Fig 25, alternately so that a valve 163 is reciprocated to cause reversals in the fluid flow to cylinder 106. Cylinder grinding.-Grinding wheel 67, Fig. 2, is brought into the operative position and valve 157, Fig. 25a, is turned to cause the hydraulic circuit to displace piston 89 until it abuts the screw 93, which has been set to ensure that the support 50 is horizontal, disengage the clutch 1472, displace the piston 206 to engage the gears for working drive and displace the piston 104 so that the slide 2 is reciprocated. To .stop the slide, a valve 152 is turned to move the slide to its extreme left position and put the gear box in neutral by displacing the piston 206 to its central position in which it is retained by the lock 239. To re-start the slide, the valve 152 is returned to its original position; the spindle 8 rotates again when the lock 239 is lifted by - turning a valve 158, Fig. 25. Face grinding.-Grinding wheel 68 is brought into the operative position and the control on the drum 131 is turned to bring the next set of stops into operative position. The valve 152 is turned causing the slide 2 and the member 110 to travel to the right until the abutment 1141 strikes the stop 243 in which position the end face of the wheel 68 is in immediate proximity of the plane face to be ground. The valve 158 is now turned to cause the spindle 8 to rotate. Feed is effected by hand, for example, by displacing the spindle 8. At the end of the operation, the valve 152 is turned to cause the slide 2 to return to its extreme left position. Screw-thread grinding.-With grinding wheel 69 in the operative position and the drums 130, 131 turned to the appropriate setting, a valve 154 is turned to cause displacement of the piston 89 and incline the support 50 to the helix angle of the thread and to engage the clutch 1472. The valve 152 is now turned displacing the slide 2 until the abutment 1141 strikes the stop 244. The hand wheel 98 is turned to bring the slide 47 to the correct position and the valve 158 is momentarily rotated to free the piston 206 which causes the spindle 8 to run at working speed driving 'through the clutch 1472, the lead-screw 115. The travel of the slide 2 continues until the plunger 181 is lifted by contact with a stop to energize the magnet 165 which operates its valve 163 to cause the piston 206 to engage the high speed reverse drive in the gear box. This drive is terminated when the plunger 180 is lifted to energize the magnet 164 which displaces the piston 206 to its mid-position in which it is retained by the lock 239. A further traverse can be started by momentarily rotating the valve 158 again. The manually-operated valves, which are rotated to predetermined positions to effect the various series of operations, are mounted on a panel at the front of the machine.