Cartridge having a pyrotechnical actuation of a payload with a safety device

DETAILED DESCRIPTION The present invention by contrast proposes a particularly satisfactory solution which is based on simple means and provides complete satisfaction, using, in addition to the above mentioned chain breaking slide valve, a double safety arrangement made up of completely separate parts and functioning on radically different principles.
In the first safety arrangement proposed, the above mentioned slide valve is fixed in the chain breaking position by a stop, held axially until subjected to a predetermined stress intensity, and attached to an inertia block which displaces it under the effect of the acceleration due to the firing of the shot.
To provide the second safety factor, which is very advantageous to use according to the invention, the pyrotechnical chain comprises in addition another chain breaker provided by interposition of a sealing-block which is also held axially below a predetermined stress and is capable of being driven out by the pressure of combustion gas.
This other chain breaker is preferably placed between the ejection charge and the beginning of the delayed action pyrotechnical chain.
More particularly it may be provided by the fact that the block, which is slidable in a bore, has a shoulder accommodating a toroidal seal which is larger than the bore and abuts against it in the position where the block breaks the chain when the pressure of the gas forces the block with its seal into the bore.
In one particular embodiment, the stop is advantageously held in a position of immobilising the slide valve by a toothed washer or a thin plate capable of yielding under a predetermined force.
According to another feature of the invention, the pressure of the gas acting on the sealing-block displaces the block axially in the opposite direction to the axial movement of the inertia block due to the acceleration caused by the firing of the shot.
Other features and advantages of the invention will be apparent from the detailed description given below with reference to the attached drawings illustrating by way of a non-limiting example a preferred embodiment of the present invention