GB963622A - Method of and apparatus for automatically measuring and controlling workpieces with a broken surface to be machined by precision machine tools - Google Patents

Abstract

963,622. Measuring length electrically. SZERSZANGEPFEJLESZTO INTEZET. April 4, 1962 [April 11, 1961], No. 12970/62. Heading G1N. The common height of a number of similar workpieces is measured by a feeler which automatically follows the broken surface levels, thus producing a pulsed output signal which is only connected to a meter when a pulse produced by double differentiation of the output signal causes a switch to close at the beginning of each height measurement. As shown (Fig. 1a) a table 5, carrying a number of workpieces 2 of the same height, is moved relative to a feeler gauge 1. When the tip of the feeler touches the first workpiece it automatically explores its shape, thereby displacing an armature 6 (Fig. 2) and producing an unbalance signal from a measuring bridge 7, which is phaserectified at 11 (Fig. lb), amplifed at the first part of valve 16, and differentiated by capacitor 17 and resistor 18 (Fig. 1c). A rectifier 19 now cuts off the negative pulses (Fig. 1d) and the resulting signal is amplified at the second part of valve 16, to be differentiated again by capacitor 21 and the winding 22 of a polarised relay 15 (Fig. le). The negative parts of this signal (Fig. 1f) cause polarised relay 15 to close contacts 12, whereby capacitor 13 is charged to the peak value of the pulsed output signal, corresponding to the height of the workpieces 2, which value is measured by a valve voltmeter 14. Constructional details are given (Figs. 3, 4 not shown) of a feeler gauge comprising two spring-loaded feelers stated to be suitable for measuring rotating workpieces with cylindrical or conical broken surfaces.