| 摘要 |
579,659. Electromagnetically - operated timing mechanism for bomb dropping &c. KELK, W. H. H., and BURNS, D. O. Oct. 18, 1943, No. 17047. [Class 38 (ii)] [Also in Group XXXVII] A train of electrical pulses of a frequency that is a sub-multiple of a fundamental frequency is obtained by feeding the " fundamental " pulses successively to the contacts of a rotary uniselector switch T<2> that is operated step by step in time with the pulses and connecting, say, every second or every fifth or every tenth contact of the switch T<2> to an outgoing line a by means of a preselector switch X. In the form shown, pulses at the fundamental frequency are generated by two cross-connected relays AP, BP the timing of which is varied by adjusting the resistance BPR in series with an extra winding of the relay BP. These relays are first set in operation by momentarily closing a switch FS. This energizes a relay FR closing a maintaining circuit at FR and also completes the circuit to the relays AP, BP which alternately energize and de-energize each other. Each time the relay coil AP<3> is energized contacts AP<2> and AP<3> are also closed. The latter causes the energization of the magnet TS4 which steps round the uniselector switch having two banks of contacts T/ T<2>. The contacts T<1> bring into play another positive terminal so that, even if a " stop " switch Y is opened the uniselector switch will continue to step round till the left hand contact T<1> is again on contact 1. The switch AP<2> conveys current to the second bank of contacts T<2> and every fiftieth or twenty-fifth or tenth or fifth or second contact of this bank is connected to the line a by moving the preselector switch X to an appropriate position. The switch X consists of two contact arms x<1> and a contact disc x<1> which move together and engage fixed contacts indicated by arrows. Thus a selected submultiple frequency is delivered to the line a which may energize a relay OR and operate a switch OR at this submultiple frequency. The arrangement may be used for dropping bombs at selected time intervals. Specification 478,391, [Group XXXVII], is referred to. |
