| 摘要 |
<p>1,099,380. Gauging. MARCONI CO. Ltd. March 11, 1966 [May 5, 1965], No. 18923/65. Heading B3B. [Also in Divisions G3 and G4] Means for accurately indicating the angular position of a machine tool control shaft in digital form comprises an annular scale drum 3 connected to the shaft 1 by a backlash-free coupling 5 and supported on a thrust bearing 4. The scale drum is provided at its periphery with thirteen circular tracks 16, each track consisting of alternate raised and unraised portions and co-operating with a respective transducer 6. Each transducer comprises a nozzle (8) supplied via a restriction (7) and chamber (9), the latter being partly defined by a diaphragm (10) carrying a ferrite slug (11) suspended by wires (20) from a resilient spider (12). The slug (11) co-operates with coils (13-15) to produce an electrical output signal as described below. When an unraised track portion adjacent a nozzle is replaced by a raised portion, the pressure in chamber (9) rises and slug (11) moves to magnetically link coils (13) and (15) to a greater extent than it links coils (13) and (14), coil (13) being connected to an A.C. power source. Coils (14, 15) form the unbalanced arms of a bridge network. In an alternative embodiment (Fig. 3, not shown) each track co-operates with a pair of air-fed conduits (22, 23) and the back pressure in these conduits controls a bistable fluid amplifier via lines (30, 31) the amplifier having output conduits connected to an indicator or control member.</p> |
