An electropyrotechnic device for sequentially triggering the operation of a battery of gas generators. The ignition of double-base propellant blocks is obtained by the combination of EFI and an IFOC, arranged so that the airtight barrier between the cavity containing the donor secondary explosive and the downstream chamber containing the secondary receiving explosive is only one part of the closing element of the back end carrying the nozzles, integral with the ring. The control electronics of the EFI are contained inside a housing capping the back end of the powder generator with the entire system being closed by a cap.

A two piece thru-bulkhead initiator. A first member carried by a rocket mr encloses a pyrotechnic charge and a receptor charge. A second member enclosing a confined detonating fuse and a receptor charge is releasably secured to the first member. The mating surfaces between the two members must not contain air gaps.

An improved detonation transfer apparatus is set forth. In one embodiment, it incorporates a transverse bulkhead having selected explosive materials on both sides thereof. The bulkhead is shaped into a concave lens to focus the shock wave toward a focal point so that one of the explosive materials directs a shock wave into the other of the explosive materials, thereby triggering sufficient shock wave pressure for detonation. In an alternate embodiment, a blasting cap transfers detonation to a first secondary explosive material which forms a flyer; the flyer travels across the space, impacting with a metal transverse bulkhead which in turn transfers a shock wave through the bulkhead into another explosive shaped in the form of a pellet. This has a high impedance reflector plate in it. The reflector plate is approximately parallel to the transverse bulkhead so that shock wave reflection occurs at the plate and further increases shock wave pressure, thereby exceeding the levels necessary for detonation, and detonation is thereby transferred into the detonating cord.

An improved arming and firing device especially suited for rocket motors. An explosive donor charge is packed against a bulkhead formed in the body of the device. Shock energy generated by the donor charge and transmitted through the unruptured bulkhead sets off a shock-responsive receptor charge, which in turn initiates a pyrotechnic or explosive rocket motor-actuating output charge. The bulkhead prevents blow-by or leakage of the rocket's combustion products. The donor charge is ignited by an electrically activated detonator. The detonator is carried by a moveable holder. The holder is moved against a return spring by electromechanical driving means. Arming the device is accomplished by moving the holder to position the detonator in firing train with the donor charge, thereby simultaneously bringing electrical contacts on the detonator into contact with electrical leads on a switch plate located adjacent the holder and thus closing the firing circuit. In the event of an abort or power failure, the return spring removes the detonator from the firing train, thereby breaking the firing circuit as well. A separate circuit is provided for shorting the detonator in the safe condition. Additional circuits may be provided for monitoring the status of the device. A viewing port may be provided for direct or remote visual observation of the condition of the device.

Detonation of an acceptor charge by a donor charge across an intervening where the two charges are not axially aligned is achieved by shaping the respective charges to control the direction of the fragments of the donor charge and their impact pattern upon the acceptor charge.