| 摘要 |
1,154,736. Control of machine tools. OERLIKON-BUHRLE HOLDING A.G. 31 Aug., 1966 [2 Sept., 1965], No. 38911/66. Heading G4H. In apparatus for detecting the movement of, for example, a machine tool from a fixed datum position, pulses from photo-cells sensing either a scale 17 (Fig. 1) moving with the stand 11 of the machine tool or a rotating slotted disc (75, Figs. 5 and 6, not shown) are not accumulated in a counter until a cam 29 opens a switch 27 by releasing a plunger 28. In the embodiment of Fig. 1 switch 27 is opened just before two photo-cells 24 are symmetrically positioned over the first division line of the scale 17. When the photo-cells 24 are symmetrically positioned over the first division line of the scale a transistor 43 (Fig. 4) in a multivibrator 33 is rendered conducting and transistor 44 is cut off so that the negative voltage on a conductor 54 renders transistor 60 conducting to open gate 34. As the photo-cells move over the divisions 18 (Fig. 1) a transistor 36 (Fig. 4) is rendered successively conducting and non-conducting to apply pulses via conductor 43, transistor 63 and conductor 84 to the counter. In the second embodiment (Figs. 5 and 6, not shown) two photocells (79, 80) sense slots (77, 76 respectively) in the disc (75), the gate (34) being enabled when the first slot (77) is in front of the photo-cell (79). |
