Abstract: An actuator for use in conjunction with a detonator for blasting comprises electronic circuitry which on receiving input signals generates an output arm signal to arm a detonator, and then after a predetermined delay an output actuate signal to fire the detonator and an associated explosive charge. The delay is capable of being remotely and precisely set. The actuator is preferably used in conjunction with a control device which has a microcomputer whose memory contains arm and actuate codes and which has both arm and actuate keys. This microcomputer is such that the actuate key must be operated within a predetermined period after operation of the arm key, otherwise an actuate signal is not transmitted to the actuator.

Abstract: A detonator of the type comprising an electrically-fired fusehead in an explosive charge comprises a conditioning means which has two states, normal and armed, and a control means for effecting a change from normal to armed state. The detonator cannot be fired when the conditioning means is in the normal state, and the control means may comprise electronic circuitry for recognizing and acting only on appropriate control signals. Accidental and unauthorized firing can thus be eliminated. Other embodiments include an actuator incorporating a delay capable of remote precise calibration and a safety device for reducing still further any risks involved when using these detonators in blasting operations. The detonator is preferably in modular form wherein the coupling together of the detonator, actuator, power unit, etc. forms the necessary electrical connections.

Abstract: An actuator for use in conjunction with a detonator for blasting comprises electronic circuitry which on receiving input signals generates an output arm signal to arm a detonator, and then after a predetermined delay an output actuate signal to fire the detonator and an associated explosive charge. The delay is capable of being remotely and precisely set. The actuator is preferably used in conjunction with a control device which has a microcomputer whose memory contains arm and actuate codes and which has both arm and actuate keys. This microcomputer is such that the actuate keys must be operated within a predetermined period after operation of the arm key, otherwise an actuate signal is not transmitted to the actuator.