Patent GB-1080566-A (GB)
Title: Improvements in and relating to grinding machines
IPC: B24B47/20
Filed: 1964-11-13
Abstract: 1,080,566. Grinding. LANDIS TOOL CO. Nov. 13, 1964 [Nov. 15, 1963], No. 46252/64. Heading B3D. A machine for grinding axiallyspaced portions #1, #2 of a workpiece W comprises a work support 11, a grinding wheel 21 rotatably mounted on a support 20, and a feed mechanism for moving the wheel support towards and from the work support consisting of a feed screw 51, a screw-engaging member 54 in operative relation with the feed screw, means 63, 64 to actuate the member 54 to advance the wheel support to grind a workpiece portion to a predetermined diameter, and means 70-75 having a limited range of movement to change the relation between the feed screw 51 and member 54 so that when the member is then actuated, it will advance the wheel support to grind a workpiece portion of different diameter. The work support 11, which carries a headstock 12 and tailstock 13 for the workpiece W, the headstock having a motor 110 for driving the workpiece, has a cylinder 30 slidable on a piston 31 having rods 32, 33 carried by uprights 34, 35 on the machine bed whereby the support is movable to position the portions #1, #2 of the workpiece in alignment with the grinding wheel; the position of the support 11 is accurately determined by engagement of a plunger 42 actuated by a device 43, 44 with notches 41 in a plate 40 carried by the support. The grinding wheel support 20 is movable towards the work support by a rapid feed piston 50 which is slidable in a cylinder 62 and is threaded on the feed screw 51. The screw engaging member 54 consists of a worm gear on a shaft 55 which has a second worm gear 56 engaging a worm 57 having a pinion 60 cooperating with a rack 61 movable by a piston- and-cylinder device 63, 64 for effecting a slow feed of the wheel support; feed can be effected by a handle 58 which, together with the worm 57, can be disconnected from the rack and pinion 60, 61. The feed screw 51 is also engaged by the means for effecting the limited movement which consists of a worm-wheel 70 engaging a worm 71 connected to a pair of pistons 72, 74 slidable in cylinders 73, 75. The worm 71 has a rod 76 having a worm 80 forming part of a fine feed mechanism operable during finish grinding. The various piston-and-cylinder devices are controlled by a hydro-electric relay circuit and, upon depression of a start button, a pump is started and the work support 11 is located in position by the plunger 42 engaging a notch 41 on the plate 40. Operation of an infeed lever actuates a solenoid 4 of a valve 120 so that fluid pressure from the pump is supplied to the rapid feed cylinder 52 to advance the piston 50, screw 51 and wheel support 20, the initial movement of which causes a limit switch 8LS to be actuated to start the headstock motor 110. The advancing wheel support then operates a limit switch 9LS which through a timer relay contact energizes the solenoid 6 of a valve controlling the supply of fluid pressure to the cylinder 64 of the slow feed piston 63, the movement of which causes slow movement of the feed screw and wheel support. At the end of the grinding feed and an interval for spark out, the solenoids 4, 6 are de-energized so that their valves are moved to cause reverse operation of the rapid and slow feed pistons 50, 63 to retract the wheel support 20. The headstock motor is then stopped and the plunger 42 is withdrawn from its notch to permit the work support 11 to be moved by fluid pressure supplied to one side of the piston 31 and the plunger 42 is engaged with the next notch to align the grinding wheel with the portion #1 of the workpiece which is smaller in diameter than portion #2. The movement of the work support 11 actuates a limit switch 17LS controlling a relay which, when the plunger 42 has engaged the notch, causes operation of a solenoid 5 controlling a valve which moves to connect fluid pressure to cylinder 72 moving worm 71 so that the feed screw 51 is rotated to shift the position of the wheel support. When the infeed lever is then actuated, the solenoids 4, 6 are again actuated to operate the valves 120, 130 so that fluid pressure is supplied to the cylinders 52, 64 to effect the rapid and slow feeds of the wheel support as before to grind the portion #1 of the workpiece to a different diameter to the portion #2.