| 摘要 |
<p>877,995. Electric selective signalling systems. LEHNER, C. L., [trading as FERNSPIECHUND SIGNALBAU LEHNER & CO. KOMM.- GES.], and HOESCH BERGBAUTECHNIK G.m.b.H. Sept. 9, 1959 [Sept. 20, 1958], No. 30783/59. Class 40 (1). [Also in Group X] In an arrangement for remotely controlling the displacement of composite frames of pit props (see Group X), the frame selection is governed by switch RW at a remote point which energizes one of a series of differently tuned transmitters FS1-FS3. The transmitter signal is applied to line a, b and energizes a similarly tuned receiver, e.g. FE, forming one of a series of selective receivers, one of which is allocated to each frame. The receiver output prepares a number of devices SVI-SVIII, controlling the displacement of the props, for operation by polarized signals applied via switch PSW and lines LI-LIII.</p> |
