| 摘要 |
1,185,557. Semi-conductor devices. R. KREEB and A. OSTERTAG, [trading as RAFI RAIMUND FINSTERHOLZL ELEKTROTECHNISCHE SPEZIAL-FABRIK]. 12 Dec., 1967 [10 April, 1967], No. 56346/67. Heading H1K. A contactless electronic switching device comprises a permanent magnet having a polepiece which can be moved relative to a field plate to effect the switching action. As shown, Fig. 1, a press key comprises a permanent magnet 3 having polepieces 2, 14 and supported within a housing 6 of ferromagnetic material by a non-magnetic slide bush 9. The magnet can be moved in the direction P against the force of a return spring 4 by pressure applied to button 1 so as to bring polepiece 14 over a field plate 11 mounted on a carrier 10. Polepiece 14 has a tapered portion 15 to concentrate the magnetic flux on to the field plate. A transistor amplifier or electronic switch may be mounted in space 16 or externally to the device. In a modification, Fig. 2 (not shown), a second field plate (17) is mounted at the opposite side of the housing to the first plate and positioned so as to provide a normally closed contact, the lower pole shoe being suitably shaped to co-operate with both field plates. |
