A firing mechanism for pyrotechnic flare signalling device

摘要

A pyrotechnic flare signalling device firing mechanism has a tubular casing (13) with a master plunger (31) projecting from one end (16) and slidable in the casing (13) in tandem with a slave plunger (32) which is urged against a stop pin (51) in the casing (13) by a coil spring (35) acting between the plungers (31 and 32). A probe (36) on the slave plunger (32) extends towards a firing pin (25) at the other end of the casing (13). A ball (29) is located in a dished recess (28) between the firing pin (25) and the probe (36). The diameter of the ball (29) is such that thrust imparted to the slave plunger (32) by extension of the coil spring (35) is transmitted to the firing pin (25) through the ball (29) when the device (10) is upright whereas the probe (36) is always spaced from the firing pin (25) when the ball (29) is displaced to one side because the device is not upright. The master and slave plungers (31 and 32) are formed with cooperating spiral ramp surfaces (38, 41) whereby the slave plunger (32) is rotated within the casing (13) by urging the master plunger (31) into contact with it whilst compressing the coil spring (35) between them, that rotation of the slave plunger (32) displacing it from the stop pin (51) and freeing it for axial movement towards the firing pin (25) with expansion of the coil spring (35). <IMAGE>