Patent GB-1143227-A (GB)
Title: Movement control apparatus
IPC: B24B49/00
Filed: 1966-03-21
Abstract: 1,143,227. Grinding. A. K. LITTWIN. 21 March, 1966 [13 May, 1965], No. 12313/66. Heading B3D. Apparatus for controlling a movable part, such as a grinding wheel, in a machine having a regular law of operation and providing a plurality of ranges of movement of the part each having different movement characteristics comprises a control unit for each range capable of controlling the duration of the range in infinitesimally - adjustable increments, and means automatically successively connecting the control units in controlling relation with the machine at the end of respective ranges of movement and terminating a cycle of operation of the machine at the conclusion of the last of the ranges of movement. The movable part may consist of a grinding wheel 18 which is vertically movable by rotation of a screw 22 through the ranges of movement on a post 20, the latter being vertically adjustable on the machine for effecting a rough vertical adjustment of the grinding wheel. The machine has a work-table 14 which is longitudinally reciprocatable to move a workpiece 16 past the grinding wheel, and the grinding wheel is movable transversely to fully grind the workpiece if the latter is wider than the grinding wheel. The screw 22 has a pinion (30, Fig. 4) engaging a rack (28) movable by a single or double hydraulic device (24) to effect the movement of the grinding wheel through its plurality of ranges, the device (24) being controlled by the machine controls (26, Fig. 6) which, in turn, are controlled by relay contacts (40b, 42b, 44b, 46b). The screw 22 is also connected by a shaft (32, Fig. 3) and bevel gearing to a spindle (34) of a control means 38, the shaft being secured to a beam (36) which carries armatures (48a, 50a) at its opposite ends movable relative to coils (48, 50) of control units (47, 49, Fig. 7). The units control a series of individual units (54, 56, 58), which, in turn, control respective ranges of advance of the grinding wheel, and a unit (60) which controls the reversing of the feed of the grinding wheel. Each unit (54, 56, 58, 60) has primary and secondary coils and armatures (62a, 64a, 66a, 68a) which are adjustable to vary the inductance of the coils by a rack-andpinion mechanism (70, 72) and a hand wheel (74). The units (54, 56, 58) can be selectively connected by a series of switches (88c) of a rotor 88a to an amplifier tube (94) and their armatures are adjusted to supply a positive bias to the tube (94) which in turn maintains a positive bias on a tube (96). The tubes are also supplied with a negative bias from the control unit 47 which increases as the beam (36) is moved during feed of the grinding wheel until it shuts off the tube (96) and deenergizes a selected relay (40, 42, 44) associated by a second series of switches (88b) with respective units (54, 56, 58), the relays controlling the machine controls (26, Fig. 6) for the device 24 and the switch rotor (88a) to effect operation of the switches (88c, 88b) for selecting the reset unit for controlling the feed of the grinding wheel Unit (60) operates to control the reversing of the grinding wheel feed and provides a positive bias to tubes (94, 96) which conduct until shut off by the negative bias from the unit 49 upon reverse movement of the beam. The units may be so adjusted by the positioning of the armatures that when unit (54) is in circuit, the grinding wheel removes 0À002 inch, when unit (56) is in circuit, the grinding wheel removes 0À001 inch, and, in the final range, when unit (58) is in circuit, the grinding wheel removes 0À0005 inch. Thereafter, the unit (60) is placed in circuit to withdraw the grinding wheel and re-sets the circuit in readiness for the next cycle of operations.