| 摘要 |
872,887. Transducers. COSMOCORD Ltd. Aug. 19, 1958 [Aug. 19, 1957], No. 26097/57. Class 40 (1). [Also in Group XXXIX] A transducer comprises an element displaying the Hall or magneto-resistive effect mounted stationary in the air gap of a magnetic structure, and means for shunting the magnetic field across the gap to an extent depending on the magnitude of the parameter to be measured. In Fig. 1 an element 5 (e.g. of indium antimonide) is mounted on an insulated support in the gap of a permanent magnet 1, the gap being preferably only just large enough to take the element, and the pole pieces being reduced in width to intensify the field across the gap. A shunt path is provided by an armature 8 mounted on a resilient diaphragm 7 to which motion is transmitted from the stylus 16, damped by a friction pad 13. Movement of the stylus alters the flux through the element and an output can be obtained by the Hall or magneto-resistive effect. In an alternative form (not shown) the armature 8 lies over a further set of pole pieces arranged in zig-zag form to provide a long air gap. Also, the armature can be pivoted at its centre and have a differential action on two transducer elements. The armature can penetrate the shunt gap instead of lying adjacent to it. Temperature effects can be avoided by connecting two transducer elements as adjacent arms of a bridge circuit. The device can be used as a strain gauge, thickness gauge, accelerometer or pressure-sensitive device. The armature 8 can be omitted if the whole diaphragm is of resilient magnetic material. The element 5 can be one of those disclosed in Specification 872,886, but preferably has annular electrodes in the manner of a corbino disc. |
