| 摘要 |
<p>1,206,591. Position indicating. NATIONAL RESEARCH DEVELOPMENT CORP. 2 Oct., 1967 [5 Oct., 1966; 28 Nov., 1966], Nos. 44488/66 and 53180/66. Heading G4H. The datum zero position of a position indica ting device may be varied by switches S1A, S2A, S3 (Fig. 1) connected between the output lines 17 of encoders CM1-CM3 and indicators, preferably lamps L0-L9, L0<SP>1</SP>-L9<SP>1</SP>, L0<SP>11</SP>-L9<SP>11</SP>. In the embodiment described disc or drum shaped commutators CM1, CM2, CM3, sensed by lead and lag brushes and interconnected by gearing encode the rotation of a lead screw 10 attached to for example a machine tool into decimal form. The switches comprise ten pole 10-way rotary selector switches controlled by manually operable switches CK1, CK2, CK3. The lead and lag brushes for the lowest decade are either controlled by a clock track CT or from an optical grating. Since the movement of the datum zero alters which brush should be read for the two higher decades, two sets of five pairs of brushes LBL1-LBL5 and LCL1- LCL5 are provided, each set being connected to two pole 5-way switches, the pointers of which are controlled by switches CK1 and CK2.</p> |
