GB881121A - Improvements in or relating to automatic control devices in machine tools - Google Patents

Abstract

881,121. Automatic position control systems. SCHICHAU G.m.b.H., F. June 28, 1958, No. 20803/58. Class 38 (4). [Also in Group XXII] In an automatic control device for controlling the spacing between a tool head and a workpiece, such as a pattern or template controlled flame-cutting or welding machine, the height h of the tool head 1 above the workpiece is maintained substantially constant by feelers 3, 4, 5, 6. A flame-cutting machine has its burner 1 rotated about a vertical axis x-x through gearing 27 by mechanism controlled from the pattern. Feelers 3, 5 and 4, 6 respectively are mounted for tilting movement against the restraint of strong biasing springs 21, 22 on devices 10, 9 whereby any tilting movement caused by engaging an obstruction closes a contact D, Fig. 3, which acts through relay D<SP>1</SP> and produces rapid acceleration of a motor 34 to raise the head. To compensate for gradual changes in height of the workpiece, both devices 9, 10 are mounted on a bell-crank lever 7 pivoted on a horizontal knife edge 8. This lever moves easily in response to vertical movements of the feelers and carries a cam 14 which actuates either a contact A to produce upward movement of the head or a contact B to produce downward movement; both contacts energize the motor 34 through relays A<SP>1</SP>, B<SP>1</SP>, respectively. Excessive downward movement of the feelers closes a contact C which stops the motor 34. The feelers may alternatively be mounted in a vertical guide.