| 摘要 |
In an hydraulic ram a position sensor rod (1) is supported at one end in a bore in ram rod (2). A capacitance (C1) exists between the sensor and ram rods (1, 2) and a capacitance (C2) exists between the sensor rod (2) and a fixed reference electrode (13). Measurement of the ratio of (C1) and (C2) which are in the same dielectric medium gives an indication of ram rod position. Alternatively the sensor rod (1) may be arranged for movement with the ram rod (2) so that the sensor rod (1) passes beyond the reference electrode (13) and into variable coupling with a further electrode. <IMAGE> |
