Patent GB-649702-A (GB)
Title: Grinding machines
IPC: B24B19/02
Filed: 1941-12-23
Abstract: 649,702. Grinding. REISHAUER-WERKZEUGE AKT.-GES., and RICKENMANN. A. Dec. 23. 1941. No. 16575. [Class 601 A grinding machine, for cylindrical or coned bores, right or left hand internal threads and plane surfaces perpendicular to the axis, having a slide member movable back and forth in the direction of the length of the workpiece and a tool slide movable at right angles thereto, is characterized in that the slide member comprises a lower slide supported in guideways on the frame of the machine and an upper slide movable relatively to the lower slide in the direction of the length of the workpiece, such relative movement being used for thread grinding and being obtained by means of a lead screw and change wheels from the work spindle, the movement of one slide or of both slides being controlled by means of a common control device including adjustable controlling lugs. The grinding wheel 50 is carried by a shaft 27, Fig. 6, mounted in an arm 44 of bearing block 43 mounted on segmental ways 38, Fig. 8, on the carriage 42; the angle of the grinding wheel can be adjusted, to suit the belix angle of the thread, by a worm 39 operated by a handwheel 22. The shaft 27 is belt driven by an electric motor 51. A cylindrical wheel is used for grinding plain bores; a single ribbed or multi-ribbed wheel is used for grinding threads, and a cup-wheel is used for grinding plane surfaces perpendicular to the work axis. The grinding wheel carriage 42 is movable transversely of the machine frame 1 by a nut 58 engaged by a feed screw 52 which can be turned by handwheel 18; automatic feed is effected by axial movement of the screw 52, this being caused by rotation of a nut 49 which engages a screwed part 48 of the feed screw 52. Back lash is taken up by a weight P on a chain 266 secured to the carriage 42. The workpiece W is carried and rotated by a work spindle 80, Fig. 2, journalled in a headstock 94 mounted on a top slide 4; the headstock is adjustable, about a vertical axis, on the slide for grinding tapered work. The work drive comprises an electric motor M, Fig. 2, which drives a shaft 76 through a gear box 63 comprising a reversing gear 71 and two change speed gears, operated by knobs 68, 69, whereby the speed of the shaft 76 in one direction can be adjusted; the operating lever 72 of the reversing gear is connected to the rod 250 of a hydraulic piston 121. The shaft 76 is telescopic and is connected at its lower end by a universal joint 761 to the gear box and at its upper end by a universal joint 200, Fig. 13, to a shaft 201 in the slide 4 having a worm 202 driving a worm wheel 81 freely rotatable on the work spindle 80 to which it can be connected by a clutch 87; the latter is moved into various positions by means of a control handle 9 which also, by means of pinion 215 and rack 216, operates a vertically movable rod 217 having a fork 152 engaging a gear 83 keyed on the shaft 201. The handle 9 has three positions. In the " G " position, the clutch 87 is disengaged from the worm wheel 81, but a helical gear 142 on the clutch 87 is brought into mesh with a helical gear 141, Fig. 15, on a shaft 86 having a gear 85 with which the gear 83 is then in mesh; the work is thus given a fast rotation, suitable for the grinding of plain bores and plane surfaces perpendicular to the axis, such as shoulders. In the "O" position, the work spindle 80 is completely disconnected from the driving means so that the work can be rotated by hand if desired. In the " L" position, the clutch 87 is engaged and the worm wheel 81 drives the work spindle 80 at a slow speed suitable for thread-grinding; the gear 83 at this time engages the first gear of a train of change speed gears driving a lead screw 102. The top work slide 4 is mounted on longitudinally ways on the lower work slide 3, and can be moved relatively thereto by the lead screw 102 (carried by the slide 4) engaging a nut 104 (carried by the slide 3); the slide 4 carries adjustable dogs 14, 14<SP>1</SP>. The lower work slide 3 is mounted on longitudinal ways 2 on the machine frame 1 and can be moved by a handwheel 16 operating a pinion meshing with a rack secured to the slide 3. The slide 3 can also be traversed by a piston 111 secured to a lug 275 on the slide; movement of the slide 3 to the right is limited by the lug 275 contacting a stop 113; the stop is adjustable, through gears 279, 280, by a knob 17. The slide 3 carries adjustable dogs 15, 15. The hydraulic system, Fig. 26, comprises a pump 64 (driven from the gear box 63) and a main control valve 120 which controls the operation of the piston 121 the rod 250 of which operates the reversing lever 72 for the work drive. A distributing valve 119, for controlling the operation of the piston 111 which reciprocates the work slide 3, is fluid actuated under the control of the main valve 120 and can also be operated by a handlever 8. The valve 120 can be rotatably adjusted to any one of four positions by a handlever 5, movement of which also effects, through gear 253 and rack 254, Fig. 13, vertical adjustment of a rod 203 carrying a tappet 13 operated by hand or by the adjustable dogs 14 or 15; actuation of the tappet 13 rotates the rod 203 and therewith a gear 148 which meshes with a rack 150 on the valve 120 to move it axially. In the "A" position of the control lever 5, the rod 203 is in a low position in which the tappet 13 is in the path of the dogs 15, 15 on the lower work slide 3. In the " B " position, the rod 203 is moved to an intermediate position in which the tappet 13 is not in the path of any dogs. In the " C " and "D" positions, the rod 203 is in a high position in which the tappet 13 is in the path of the dogs 14, 14<SP>1</SP> on the upper work slide 4. The rod 250, Fig. 2, of the piston 121 for operating the reversing lever 72 of the work drive has pivotally mounted thereon a lever 56, loaded by a spring 55, one end of which has a nose N in contact with a cam 90 and the other end of which is connected by link 57 to the nut 49 for imparting automatic feed to the grinding wheel. The cam 90 is driven. through the reversing gear 71, by gears 88, 89, 91, and worm gearing; the gear 91 is slidable on its shaft and is normally held in position to mesh with gear 89 by a spring; it can be moved out of mesh by a fork 96, Fig. 26, operated by a piston 98 in a cylinder 99 under control of the valve 120, fluid being admitted to the cylinder when control 5 is in " A " or " B " positions. The cam 90 has a pin 136 co-operating with a lever 134 which through a link 137 operates gears 138, 139, 146, 148, Fig. 13, the latter meshing with a rack 150 on the valve 120 to move it coaxially. The machine is stated to be suitable for grinding thread gauges, the following operations being performed without removing the work from the machine. Plain internal grinding.-The control 9 is in the "G" position, so that the work is rotated at high speed; the lead screw 102 is not driven, so that the upper work slide 4 moves as one with the lower slide 3. The control 5 is in the "A" position, so that the tappet 13 is in the path of the dogs 15, 15 on the lower work slide 3; the cam 90 is not driven. The slide 3 is thus hydraulically reciprocated, the valve 120 being automatically operated at the ends of the stroke to effect reversal of traverse. The rate of reciprocation is adjusted by a throttle valve 11 in the exhaust. Operation is discontinued by moving control 9 to the " 0 position, (thus disconnecting the drive to the work) and control 5 to the "B" position. Grinding plane surfaces at right angles to the axis, e.g. shoulders.-The control 9 is in the "G" position, so that the work is rotated at high speed; the lead screw 102 is not driven, so that the upper work slide 4 moves as one with the lower slide 3. The control 5 is in the "B" position, so that the tappet 13 is not in the path of the dogs on either side. The slide 3 is moved by the handwheel 16, both sides of the piston 111 being connected to exhaust. Thread grinding: plunge-cut.-The control 9 is in the " L " position, so that the work is rotated slowly, and the lead screw 102 is driven, so that the upper slide 4 is traversed relatively to the lower slide 3. The control 5 is in the "O" position; the slide 3 is urged hydraulically to the right so that the lug 275 bears against the stop 113; the feed cam 90 rotates, so that the grinding wheel is fed in to the required depth and held there for at least one complete revolution; the pin 136 then operates the lever 134 to shift the control valve 120, whereupon the piston 121 is moved to the right; as a result, the grinding wheel is rapidly retracted, and the reversing lever 72 is thrown over so that the work reverses, the lead screw 102 reverses to move the slide 4 back to starting position, and the cam 90 is also returned to its starting position. At the end of these movements, the pin 136 again operates the lever 134 to shift the control valve 120, whereupon the piston 121 moves to the left but is arrested by a latch in a mid-position in which the lever 72 is in a neutral position. The operation can be repeated by momentarily withdrawing the latch. During this mode of operation, the dogs 14, 14<SP>1</SP> are removed from the upper slide 4. Thread grinding: longitudinal feed.- The control 9 is in the " L " position, so that the work is rotated slowly, and the lead screw 102 is driven, so that the upper slide 4 is traversed' relatively to the lower slide 3. The control 5 is in the "O" position, so that the slide 3 is urged hydraulically to the right bringing the lug 275 to bear against the stop 113. The piston 98 is held back by a screw so that the feed cam 90 is not driven. At the end of the working stroke, dog 14 on the upper slide 4 actuates the tappet 13 to move the valve 120, causing the piston 121 to move to the right; this effects withdrawal of the grinding wheel, reversal of the work and rapid return o