Patent GB-951355-A (GB)
Title: A method for the automatic control of the positioning of a plurality of movable members and apparatus to carry out the method
IPC: G05B19/42
Filed: 1962-03-29
Abstract: 951,355. Programmed control of machine tools. SOC.GENEVOISE D'INSTRUMENTS DE PHYSIQUE. March 29, 1962 [April 11,1961; March 14, 1962], No. 12188/62. Heading G3N. A precision machine tool comprises a table 1, a slide (not shown) and a rotatable tool carrying spindle 2, revolving in an axially displaceable spindle-sleeve 2a. The position of the table relative to the spindle is controlled digitally, their relative linear speed is controlled digitally and the speed of rotation and rest position of the spindle are also controlled digitally. The amplitude and end positions of the spindle are controlled analogically. A binary-coded tape 3 is read and decoded and the eight tracks are separated by a distributer 6. The number of operations performed are indicated through a register 7 by a display 9. The table and slide point-to-point control devices are identical and only that for the table is shown. Table control. Digital signals from the distributer 6 are stored in a register 8 controlling the desired-table-sitting display 10 and coarse and fine positioning devices I, II furnishing error signals controlling, sucessively, by means of a switching device IV a driving device III. The coarse positioning device I comprises a digital to analogue converter 11 feeding analogue signals to the stator windings of synchros S3-S5 coupled by gearing G1 to the table. The fine positioning device II comprises a digital to analogue converter 12 feeding analogue signals to the stator windings of synchros S1,S2 mechanically connected to a micrometric carriage 13 by gearing G2. The micrometric carriage carries a photo-electric microscope 17 scanning the image of a scale R carried by the table 1 to provide a first error signal to the switching device IV from an electronic equipment 18. The driving device III of the table comprises a gear-box G3, the gear ratio of which is set for a desired traverse speed by digital signals from the distributer 6, and a driving motor 14 controlled by the switching device IV. The switching device controls selectively,the drive by motor 19 through change-over switches 20, 21 and a phase-discriminator 23 from the synchros S1-S5. The change-over-switch 21 changes over to the second error signal from equipment 18 when the first error signal falls to a predetermined value. The appropriate gear ratios for coarse and fine positioning are selected by a switch 22. Spindle control. The spindle control is responsive to a device A numerically controlled by digital signals from the distributer 6 which define the speed of rotation and axial displacement of the spindle and the rest and tool-changing positions, and also is responsive to a memory B of the type described in Specifications 864,049 and 872,103 which stores analogue information defining the amplitudes and the positions of the washing strokes of the spindle sleeve 2a for the various machine operations. The device A comprises devices 24-28. The device 24 axially displaces the spindle sleeve 2a by a motor M1 operating through a reduction gearing 24 for rapid forward and reverse movement when a clutch E1 is engaged and in a final regulating movement when a clutch E3 is engaged. The spindle rotational speed device 25 has a register 32, digitally controlled from the distributer 6, selecting the ratio of a gear-box V2 mechanically coupling a motor M2 to the spindle 2. The spindle linear speed device 25 has a digitally controlled register 34 selecting the ratio of a gear-box V1 mechanically linking the drive to the gear-box V2 through clutches E2, E4 to the spindle sleeve 2a. The cycle of operations is controlled by the device 27 whereby digital signals from the distributer 6 are stored in a register 35 controlling an electronic switch 37 selectively operating devices 24, 26. An identification device of the tool carried by the spindle comprises a register 41, responsive to digital signals from the distributer 6, controlling a display of the tool number. A rack 42 receives the tools and a member 43 draws the attention of the operator and locks the spindle if the tool is not suitable. The analogue memory B is selectively controlled by a device C, responsive to digital signals from the distributer 6, to control the cycle of operations of device 27. Specifications 686,274, 756,394 and 875,491 also are referred to.