Patent GB-914830-A (GB)
Title: Tow target
IPC: F42B4/24
Filed: 1961-06-16
Abstract: 914,830. Electric selective signalling systems. DEL MAR ENGINEERING LABORATORIES. June 16, 1961 [June 20, 1960], No. 21912/61. Class 40 (1). [Also in Group XXI] In a system for controlling the detonation of a number of smoke generators and flares in a towed target means are provided for effecting the detonations in a selected one of a plurality of sequences, referred to as programmes, the selection of a particular programme being effected by a signal transmitted from a remote location. As described, there are seven programmes, each of which comprises four stages. Once a particular programme has been selected its four stages are performed successively, each in response to a triggering pulse transmitted from a remote control station. Thus the inter-stage timing of a programme is infinitely variable. As described, each programme stage consists either of the simultaneous firing of a plurality of flares or of the successive firing of a plurality of smoke puffs. When a programme-stage consisting of a plurality of smoke puffs is triggered by a remote control pulse, the puffs are fired successively under the control of a timer in the target, and this timer can be remotely controlled so as to operate at a selected one of three repetition rates. The control circuit in the target comprises principally a multi-bank sevenposition switch 65, Fig. 6, which selects one of seven pre-wired programmes, a four-position switch 62 which causes the four stages of a programme to be performed successively, a timer 70 and a multi-position switch 80 which together sequentially fire a plurality of smoke puffs 40, and a radio receiver 32 which applies pulses to lines 1 and 2 in response to signals transmitted from the control station. Programme selection.-A desired programme is selected by applying an appropriate number of pulses to lead 1 to step switch 65 to the desired position. Advance of a programme.-A programme having been selected, its four stages are each triggered by a pulse on lead 2, each of these pulses closing a pair of contacts 1, 2, thereby advancing the programme-stage switch 62. Firing of sequence of smoke puffs.-When a programme stage requires the firing of a sequence of smoke puffs a timer 70 is started. This steps the switch 80 and fires the detonators 40. Change of rate of timer.-To change the repetition rate at which smoke puffs are fired eight, nine or ten pulses are applied to lead 1. The first seven pulses, counted by a counter 74, step the programme switch 65 through one complete revolution-thereby leaving it effectively as it was-and the eighth, ninth and tenth pulses alter the timer, these pulses being blocked from the programme switch 65 by a gate 73 which is closed by the seventh pulse. In order to select a different programme immediately after charging the timer rate pulses are applied simultaneously to both leads 1 and 2. This reopens gate 73 and the programme switch can then be advanced. It also has the effect of advancing the programme stage switch 62 one position so that it may be necessary to transmit up to four pairs of simultaneous pulses to bring the programme stage switch back to a desired position.