Patent GB-1041153-A (GB)
Title: Method and apparatus for controlling machine tools, more especially copying lathes with at least two machining tools
IPC: B23Q15/04
Filed: 1965-02-11
Abstract: 1,041,153. Copying lathes. G. FISCHER A.G. Feb. 11, 1965 [Feb. 11, 1964], No. 6069/65. Heading B3T. In a copying lathe the position of tools 6 and 9 when cutting workpiece 1b is controlled by measuring elements 32a, 32b, which measure dimensions on a previously machined workpiece 1a, compare these dimensions with set nominal values correct for any discrepancies, and then provide individual movements of the tools to correctly machine the workpiece 1b. The lathe comprises a copying slide 12, arranged on a longitudinal carriage 13 movable on guides 14, 15, and tool holders 7, 10, carrying tools 6, 9. Slide 12, has an hydraulic piston 25 spring urged against a push rod 23, to pivot a lever 20 having a follower 19 thereon, which co-operate with a template 17. An extensible rod is lengthened to bend lever 20, by a heating coil 28, and the bending is measured by a measuring element 29. Measuring elements 32a, 32b are connected to air gauges 34a, 34b having indicating tubes, and photo-cells 53a, 53b are arranged in tolerance fields. A middle field 82 defines the tolerance limits of the nominal value, while the dimensions which are too large or too small are associated with fields 81a, 81b respectively. Photo-cells 35a, 35b are connected to control devices 37a, 37b having setting motors 38a, 38b which rotate screwed spindles 39a, 39b to adjust photo-cells 41a, 41b. The latter are displaced along further indicator tubes 42a, 42b of air gauges according to the signals received by photo-cells 35a, 35b. Photocells 41a, 41b are connected through a reversing switch 48 to a high-frequency generator 50 to which coil 25 in slide 12 is connected. Measuring element 29 is connected by an air line 43, and a valve 44 to indicator tubes 42a, 42b. In operation, assuming that the workpiece diameter determined by measuring element 32a is too large, and the diameter of the bore established by measuring elements 32b is within the required tolerance, the liquid column in tube 34a is in the area 81a, and in column 34b is in the tolerance field 82. Photo-cells 41a, 41b are now set on tubes 42a, 42b with cell 41a set higher than cell 41b under the influence of photo-cells 35a, 35b and generator 50 heats coil 28 to extend rod 27 in slide 27. Lever 20 bends, and the bend is measured by element 29, so that air is supplied to tube 42a or 42b according to the position of valve 44. The heating of rod 27 is stopped as soon as the liquid column in the tube 42a or 42b reaches the height of the photocell. The bending of lever 20 also moves piston 25 so that the slide 12 is adjusted relative to the work and the slide is set to the corrected position when the lever ceases to be heated. A change-over switch 48 used in conjunction with valve 44 provides for setting either of the tools 6 and 9. The lathe may have more than two tools and for indicating excessively large deviations in dimensions, photo-cells which emit a signal for actuating an optical or acoustic warning device, or an emergency machine stopping device, may be provided.