Patent GB-1057773-A (GB)
Title: Improvements in and relating to grinding machines
IPC: F15B21/08
Filed: 1964-02-05
Abstract: 1,057,773. Grinding. LANDIS TOOL CO. Feb. 5, 1964 [Feb. 7, 1963], No. 4822/64. Heading B3D. A grinding machine for machining axially spaced portions of a workpiece W, each having a different diameter, comprises means for rotatably supporting a workpiece, a feeding mechanism for advancing and retracting a cutting tool 14 relative to the workpiece, means for effecting relative longitudinal movement of the work supporting means and the cutting tool, means to control the longitudinal movement to position the axially-spaced portions of the workpiece successively in operative relation to the cutting tool, a caliper 10 mounted for transverse and longitudinal movements relative to the workpiece, and means to effect the movements of the caliper in sequence with the longitudinal movement of the work supporting means to position the caliper in operative relation to the workpiece to be machined. The workpiece W has portions (A, B, Fig. 2) to be ground to different diameters and is mounted between centres (124, 125) on a work carriage 123. The caliper 10 has work-engaging faces 70, 71 and a probe 72 connected to the core 81 of a transducer 80 and urged by a spring 82 into engagement with the workpiece, the movement of the probe being limited by a stop 76 engaging a slot 75. The caliper is carried by horizontal leaf springs 12 on a support 11 depending from a member 13 in turn supported by a pair of vertical leaf springs 21 from a slide 20 mounted on ball guides 30 on a pair of guide rods (31, 32, Fig. 2), the slide being movable towards and away from the workpiece along the guide rods by a piston in a cylinder 41 mounted on a vertical member 33. The member 33 has upper and lower slide members 45 containing spaced pairs of ball sleeves (47, Fig. 4) engaging horizontal guide rods 50, 51, the member 33 being reciprocatable along the guide rods by means of a piston and cylinder device (60, 63). The coil 80 of the transducer is connected to a master transducer (100, Fig. 6) having a probe (102) engaging a cam 110 having portions A, B which are selectively engaged by the probe which is thereby positioned according to the diameters of the portions A, B of the workpiece. Alternatively, the size control may be effected by a tape control or the probes may be positioned by valves, switches, mercury column or other control elements. An air jet A coacts with a member 15 on the support member 11 to control the advancing movement of the caliper so that it engages the workpiece with a uniform force, and a second air jet (B, Figs. 2 and 5) produces a signal when the caliper is in its retracted position. In operation, the carriage 123 is initially in its right-hand position (Fig. 2) for grinding portion A of the workpiece (shown dotted) and the caliper 10 is also in its right-hand position. When a push button is depressed a relay circuit is actuated to operate a solenoid-operated valve (130, Fig. 5) controlling the supply of fluid pressure to a cylinder (136) to advance the grinding wheel 14 to machine the portion to a size determined by a limit switch which is in the circuit controlling the supply to cylinder 41. With the caliper in its retracted position air jet A is restricted by member 15 and a pressure switch is actuated to cause fluid pressure to be supplied to cylinder 41 to advance the caliper until caliper 10 engages the workpiece, the slide 20 continuing to advance and springs 21 yielding until, at a predetermined pressure, member 15 moves away from jet A. As the workpiece is ground, the pressure at jet 15 controls the supply to the cylinder 41 so that the shoes 20 engage the workpiece with a constant pressure. When the portion A of the workpiece is to size, the probe 72 positions the core 81 so that transducer 80 co-operates with the master transducer to effect retraction of the grinding wheel and the caliper, which, in its retracted position, restricts air jet (B) and produce a signal to operate the circuit so that the carriage 123 is moved to the left by a cylinder device (160, Fig. 5), cam 110 is positioned so that portion B sets the master transducer for the size of portion B of the workpiece which is now opposite the grinding wheel, cylinder (60) is supplied with fluid so that piston (61) moves the caliper 10 along guide rods 50, 51 to position the caliper opposite the portion (B) of the workpiece, and a limit switch is actuated to advance the grinding wheel and thereafter the caliper, as before, for the grinding of the portion (B) of the workpiece, after which the parts are returned to their initial position in preparation for grinding the next workpiece.