Circuit arrangement for rocket launchers

Claim 1

In a device for launching a plurality of rockets each containing a detonator device arranged in a firing circuit, a circuit for controlling the firing of the detonator devices, comprising, in combination: a firing key connected for applying firing energy to the detonator devices; mode selector switch means connected for controlling the mode of operation of said circuit and switchable between a first position in which it causes all previously unfired detonator devices to be fired in sequence when said key is actuated and a second position in which it causes one detonator device to be fired each time said key is actuated, successive actuations of said key causing successive detonator devices to be actuated; and control circuit means connected between said key, said mode selector switch means and the detonator devices for sustaining the selected mode of operation of said circuit despite malfunctions in the firing current path of one or more of the detonator devices, said control circuit means including: a plurality of thyristors each having one main electrode arranged to be connected to a respective detonator device; an electronic switch one side of which is connected to said key and the other side of which is connected in common to the other main electrodes of all of said thyristors; a clock pulse generator connected to control the operation of said electronic switch; a counter and decoder connected between said generator and the control electrodes of said thyristor; a digital control unit connected between said selector switch means and said generator for controlling the operation of said generator; and a current sensor connected for sensing the current conducted by said electronic switch and producing an output signal when it senses a current level corresponding to that drawn by an operative firing circuit, said sensor being connected to apply its output signal as an input to said control unit; wherein when said switch means is in its said first position, said pulse generator produces an output at a first frequency, composed of pulses whose duration is different from the iNterval between pulses, which causes each of said thyristors to be triggered into conduction in sequence by the output signals from said decoder, and said control unit is responsive to the switching of said selector switch into its said second position for causing said generator to produce an output at a second frequency higher than said first frequency upon the actuation of said key and until said sensor produces its output signal, to then produce an output at said first frequency to fire an operative detonator device, and to then stop.