Patent GB-1465810-A (GB)
Title: Missiles
IPC: F42C15/20
Filed: 1975-05-22
Abstract: 1465810 Arming missiles BRITISH AIRCRAFT CORP Ltd 22 May 1975 [27 June 1974] 28620/74 Heading F3A A missile comprises a warhead, an arming unit, and a boost motor, the arrangement being such that the missile is armed only upon (a) ignition of the boost motor, and thereafter upon the missile, (b) attaining a satisfactory rate of acceleration and (c) having travelled a predetermined distance from a launcher. In the embodiment, the missile comprises a detonator 74 mounted in a barrel 46 which is urged from a safe to an armed position by a spring 76; a boreriding pin 14 biased outwardly by a spring 58; a pin 60 on which are pivoted an acceleration latch 32, a launch latch 18, and an obstruction latch 42; electrical contacts 36 carried by the pin 14 for alternate contact with fixed contacts 38 or 40; explosively actuated distance latches 22, 24; explosively actuated cotter pins 28, 30; a reel (not shown) for trailing a guidance wire or a lanyard; and two break-loops of fine wire (not shown) threaded over selected turns of the guidance wire or lanyard to provide an electrical signal when a predetermined length of the wire or lanyard has been paid out corresponding to a defined distance between the missile and its launcher. In operation: a cap 12 is removed and this permits the pin 14 to move from position 1 to position 2, and also permits a pin 16 to be ejected by a spring to leave the launch latch 18 free to move; the missile is loaded into the launcher and the pin is held in a position 3 by the wall of the launcher barrel; the missile is fired and the launch latch 18 sets back so that the pin 14 can move through a hole 20 in the latch until a shoulder 34 of the pin engages the distance latches 22, 24. The movement of the pin causes the contacts 36 to disengage the fixed contacts 38 and to cause a timer to commence operation in a boost ignition electronic module and in an arming electronic module. If the missile should encounter an obstruction, the obstruction latch 42 is thrown forwards and locks the distance latches 22, 24 against subsequent operation; when the missile has travelled a first predetermined distance, the trailing guidance wire or lanyard breaks the first break-loop and this fires the explosive actuator for the distance latch 22. Also, if the timer in the boost ignition module has reached a lapsed time within a predetermined range, indicative of a satisfactory missile velocity, the explosive actuator for the distance latch 24 is fired and the pin 14 moves to a position 5 in which the contacts 36 engage fixed contacts 40 and a neck 19 of the pin frees the acceleration latch 32; the connection of contacts 36, 40 fires the boost motor and causes the timer in the arming module to reverse its action; the acceleration produced by the boost motor causes the acceleration latch 32 to unlock the barrel 46; when the missile has travelled a second predetermined distance, the second break-loop is broken and the explosive actuator for the cotter pin 28 is fired. Also, if the timer in the arming module has returned to a lapsed time within a predetermined range, the explosive actuator for the cotter pin 30 is fired and the barrel 46 is rotated into its armed position.