| 摘要 |
1,082,056. Keyseriders. SIEMENS A.G. Sept. 21, 1964 [Sept. 20, 1963], No. 38406/64. Heading H4K. [Also in Division H2] In a keysender wherein depression of a key causes longitudinal motion of one or more sliders, the latter have at least two working positions whereat they operate contact sets of a coding circuit. The circuit comprises two resistors and a rectifier which, when inserted in the line loop in different combinations by means of the keys, present different impedances in dependence upon the polarity of the exchange battery. By reversing the polarity and observing the two values of the impedance the exchange can determine the value of the digit set up on the keyboard (Figs. 3 and 4, not shown). The latter comprises a plurality of spring-biased keys 2 having stops 5 which co-operate with cam surfaces 14 or 16 on sliders 6, 7, 8 and 9. Depression of a key causes one or more sliders to move to left or right and thereby operate corresponding contact sets 21, 22. The sliders are biased by leaf-springs 18 and they may be supported by pivoting members 17 or sliding members (Fig. 2, not shown). The bearing members or the sliders may be made of a selflubricating plastics material. The contact sets may be located at the ends of the sliders in which case they themselves act as bias springs (Figs. 5 and 7, not shown) and they may be connected to a printed circuit board located beneath the sliders (Fig. 6, not shown). The sliders may carry magnets which co-operate with sealed contact units (Figs. 8, 9 and 10, not shown). Reference has been directed by the Comptroller to Specification 935,474. |
