Patent GB-826601-A (GB)
Title: Improvements in or relating to grinding machines
IPC: B24B47/14
Filed: 1958-04-25
Abstract: 826,601. Grinding. TOYOKO&YOKABUSHIKI KAISHA. April 25, 1958 [May 2, 1957, May 4, 1957, (2),]; No. 13234/58. Class 60. [Also in Group XXXIV] A grinding machine comprises a grinding wheel spindle 69 rotatably mounted in a carrier 63 reciprocable in a casing 25, and a mechanism 37 for controlling the reciprocation of a piston valve 47 which is mounted in the casing and mechanically connected to the carrier so as to transmit reciprocating movement thereto. The spindle 69, which has a grinding wheel 36 at one end and a pulley 68 at the other, is rotatably mounted in the carrier which has a recess engaged by the ball-end of a lever 64 having a ball at its other end engaging a slot in the hydraulically-operated piston 47. Springs 48, 49 and an adjusting screw 50 position the piston 47 for control by the mechanism 37 in the form of a piston valve 37 operating in a chamber 11 which is connected by a pipe 7 to valves 4, 5 and a pump 1, and a pipe 40 to a sump 16 ; the piston 37 is also positioned in the casing by springs 43, 44 and an adjusting screw 45. In operation, with the valves 4, 5 in the positions shown, fluid is supplied through a control valve 9 to the chamber 11 which, with the piston 37 in the position shown, directs the fluid to the left-hand end of the piston 47. Movement of the piston 47 to the right displaces the carrier to the left by means of the lever 64 until the fluid can pass through a passage 56 to the right-hand end of the piston 37 which then moves to the left to cause the fluid from the chamber 11 to be supplied to the right-hand end of the piston 47 to displace it to the left, and the carrier to the right, until the fluid can pass through a passage 58 to the lefthand end of the piston 37, the pistons 37, 47 and carrier thus being automatically reciprocated at a speed determined by the setting of the valve 9 and screws 45, 50. When it is desired to dress the grinding wheel, an electro-magnet 17 is energised to actuate the valve 5 to displace the valve 4 and disconnect the fluid supply to the valve 9, and to the upper end of a piston- and-cylinder device 8, 32 connected by a rack 33 to a pinion on an arm 34 carrying a dressing diamond 35. A valve 22 having a piston 27 held in position by a cam 26 on the casing prevents fluid being supplied to the lower end of the device 8, 32 until the casing is moved along guides 24 away from the workpiece to a dressing position ; when the cam is disengaged, fluid passes to the lower end of the device to move the diamond to its operative position. The carrier, which may be arranged with its axis vertical, is supported for reciprocation in the casing by a bearing at each end of the carrier consisting of an inner race member 72 having a conical portion engaging the carrier, a cage 74 carrying a series of balls and a pin engaging an axial slot in the inner member, and an outer member 73 engaging the casing. The bearings are clamped to the carrier by nuts 80, 81 which, when wear develops in the bearings, may be further tightened to expand the inner members on the carrier. Rotational movement between the carrier and casing is prevented by an adjustable projection carried by the casing engaging a slot in the carrier. Modifications in the above embodiment consist in discharging the fluid from the inoperative ends of the pistons 37, 47 by supplementary valves, replacing the valves 4, 5 by a single compound valve, connecting the piston 47 to the carrier by a flexible wire cable, and using plain metal bearings for the bearings 72, 74. Further modifications consist in constructing the piston 47 as a slidable rod reciprocated by a crankshaft and the valve 37 as a continuously-rotatable valve. The casing may be arranged to perform transverse, vertical and/or back and forth movements.