Patent GB-1232634-A (GB)
IPC: B24B49/04
Filed: 1968-05-10
Abstract: 1,232,634. Grinding; gauging and controlling. LANDIS TOOL CO. 10 May, 1968 [12 May, 1967], No. 22186/68. Headings B3B and B3D. Apparatus for machining a workpiece includes a gauge means for determining whether the configuration of a portion or portions of the workpiece be within predetermined limits so that machining will otherwise not be initiated. As an example, if in grinding a crank-shaft, the work is set up eccentrically, grinding will not commence. The grinding machine described has gauging means comprising two air jets 35 set to play upon already machined journals of the crankshaft and has a bed 11 on which a carriage 12 can traverse longitudinally. A cradle 13 supported on the carriage 12 for pivotal movement carries a head stock 14 and foot stock 15, having centres 16, 17 between which is carried a workpiece 18, e.g. a cam-shaft. One or more cam-shaft supports 20, 21 may be provided inwardly of the centres 16, 17. A grinding wheel 23 is carried by a support 22 movable transversely on the bed 11. The cam-shaft 18 has a major shaft portion 24, cam portions 25 to be ground, and journals 27, 28 with at least one flange 30. Gauges 31, 32 are carried by gauge bracket assemblies 33, 34 mounted on the cradle 13. Each air jet member 35 has an outlet end 36 positioned a predetermined position from the surface of the journal 27 and an inlet end 37 to which is attached a pressure air hose 38. The jet member is threadably secured in a bracket 40. A guard 41 secured to the upper end of the bracket 40 has a depending front portion 44 with a slotted hole portion 45 partially enclosing the outlet end 36 of the jet member 35. The bracket 40 is secured to a carrier plate 46 which is secured to a support plate 51 by fasteners 52 extending through slots 49 in the plate 46 into threaded holes 53 of the plate 51. The carrier plate 46 is positioned by screws 56 in a block 54 secured to the plate 51. Fasteners 60 extend through a block 58, and the plate 51 and threadedly engage a block 61 having a sloped surface 63 engaging a sloped surface 62 on the cradle 13, whereby the plate is clamped to the cradle. A screw 64 supported by a bracket 65 on the block 58 protects the gauge 31 in case of endwise movement of the cam-shaft flange 30 towards the gauge as the cam-shaft is removed from the machine. Pressure air is supplied through hoses 38 to the jet members 35 of the gauges 31, 32 through pressure switches PS3, PS4 respectively. A starting lever 66 is operative through a valve 67 to control a workhead limit switch 1LS and a traverse valve 68. The valve 68 receives fluid pressure from a source P through a cycle blocking valve 72 actuated by a solenoid 73. Fluid from the traverse valve 68 is provided to opposite sides of a traverse cylinder 76 to effect longitudinal movement of the carriage 12 through a linkage 80, whereby the cam-shaft 18 is moved to selected positions in which cam portions 25 are disposed opposite the grinding wheel. When lever 66 is thrown, limit switch 1LS is closed, energizing relay 41CR, closing contact 41CR1, energizing relay 1CR, closing contact 1CR2, energizing relay 1MF, closing contact 1MF1 in circuit with a work drive motor MTR5, At the beginning of a cycle, cradle 13 is in retracted position and limit switch 6LS is open, relay 8CR is de-energized, contact 8CR1 remains closed, and slow speed relay 1ML is energized, closing contact 1ML1. The motor MTR5 is thus energized to rotate the cam-shaft 18 at a relatively slow speed. Rotation of the motor MTR5 closes a switch 1PLS, energizing relay 2CR, closing contact 2CR2, energizing timer relay 1TR. During this initial slow rotation the gauges are operative; if the journals 27, 28 are both acceptable in respect of eccentricity and diameter, pressure switches PS3, PS4 will be open, relays 3CR, 4CR deenergized and contacts 3CR2, 4CR2 closed. Thus when timer relay ITR closes contact 1TR1, relay 5CR is energized, closing contact 5CR1, energizing solenoid 73 thus opening the cycle blocking valve 72 so that the carriage 12 is moved to its first grinding position with a cam portion 25 in alignment with the grinding wheel 23. In this position the cradle 13 is rooked to effect contact between a master cam and follower roller. The movement of the cradle 13 closes limit switch 6LS energizing relay 8CR thus (i) opening contact 8CR1, de-energizing low speed relay 1ML, opening contact 1ML1 and (ii) closing contact 8CR2, energizing high speed relay 1MH, closing contact 1MH2, so that the motor MTR drives the cam-shaft 18 at high speed during the grinding operation with the grinding wheel 23 in engagement with the first cam portion 25. If one or both of journals 27, 28 is unacceptable, one or both of pressure switches PS3, PS4 will remain closed, so that when timer relay contact 1TR1 closes one or both of relays 3CR, 4CR will be energized, thus opening one or both of contacts 3CR2, 4CR2; thus relay 5CR is not energized, contact 5CR1 is not closed, and solenoid 73 is not energized, so that cycle blocking valve 72 remains in position to prevent the passage of fluid to the traverse valve 68. If this occurs, lever 66 is returned to inoperative position, opening limit switch 1LS, de-energizing relay 41CR, opening contact 41CR1; relay 1CR is subsequently de-energized, by opening of tappet switch ITS when the cam-shaft 18 is in a predetermined angular position, opening contact 1CR2, de-energizing relay 1MR, opening contact 1MF1, de-energize motor MTR5. The control may be applied to a wheel feed mechanism or other movable member to prevent initiation of a grinding cycle.