Electric circuit for firing detonators consecutively

Claim 1

ELECTRICAL CIRCUIT MEANS FOR CONSECUTIVELY FIRING A PLURALITY OF DETONATORS INDIVIDUALLY PACKAGED WITH A PLURALITY OF SEPARATE EXPLOSIVE CHARGES CONNECTED TOGETHER SERIALLY BY CABLES HAVING TWO CONDUCTORS, EACH PACKAGE INCLUDING A SWITCH BIASED TO CLOSED POSITION, A FUSE CONNECTED ACROSS THE TWO CONDUCTORS ENTERING THE PACKAGE ADAPTED TO HOLD SAID BIASED SWITCH IN OPEN POSITION AND FUSIBLE BY AN ELECTRIC CURRENT TO ENABLE SAID BIASED SWITCH TO CLOSE, AND A SOURCE OF ELECTRIC CURRENT AND A CURRENT LIMITING RESISTANCE IN SERIES WITH SAID BIASED SWITCH AND WITH A PARALLEL CIRCUIT COMPRISING AN ELECTRIC DETONATOR AND THE SWITCH HOLDING FUSE OF THE NEXT ADJACENT PACKAGE AND CHARACTERIZED BY PROPERTIES SUCH THAT WHEN SAID BIASED SWITCH CLOSES SAID FUSE IN SAID ADJACENT PACKAGE IS FUSED BY CURRENT FROM SAID CURRENT SOURCE AND THEREAFTER THE CURRENT ACTUATES SAID DETONATOR, SAID PARALLEL CIRCUIT BEING SHUNTED BY A SECOND FUSE IN SAID PACKAGE HAVING A RESISTANCE SUCH THAT THE SECOND FUSE MUST BURN BEFORE A FUSING CURRENT WILL FLOW THROUGH SAID FUSE IN SAID ADJACENT PACKAGE.