Electronic device

• US 5,159,149 A
• Filed: 06/24/1991
• Issued: 10/27/1992
• Est. Priority Date: 07/26/1988
• Status: Expired due to Term

• Current Assignee: Orica Explosives Technology Pty Limited (Orica Limited)
• Original Assignee: Plessey South Africa Limited
• Inventors: Marsden, Mark
• Primary Examiner(s): JOHNSON, STEPHEN
• Application Number:
  US07/724,492
• Time in Patent Office: 491 Days
• Field of Search: 102/217, 102/206, 102/200, 102/311, 102/312, 102/207
• US Class Current: 102/217
• CPC Class Codes: F42B 3/122 Programmable electronic delay initiators
• CPC Class Codes: F42C 11/06 with time delay by electric circuitry
• CPC Class Codes: F42D 1/055 specially adapted for firing multiple charges with a time delay

Abstract

An electronic detonator system 10 comprises a remote RF transmitter 11 and a transportable housing 12 comprising means 13 for charging energy storage means in the detonator 15 and means 14 for programming delay time means in the detonator. The programming means 14 and charging means 13 are connected to a connector 26. Detonator 15 comprises an antenna 29, a RF receiver 30, programmable delay time means 32, a switch 33, a fuse 34 and energy storage means 35. The delay time means 32 and energy storage means 35 are connected to a connector 28. In use, connector 26 is connected to connector 28 at the blast site and storage device 35 is charged and delay time means 32 is programmed. A fire command signal is then transmitted by transmitter 11 and after the delay time, switch 33 connects storage means 35 to fuse 34 thereby to energize the fuse.

Claims

1. An electronic detonator for use in a detonator system comprising the detonator, a remote transmitter and external means comprising electrical energy charging means and delay time programming means, the detonator comprising:

fuse means;

connector means for disconnectably connecting the detonator to said external means so that when connected a physical connection is established exclusively between the external means and the detonator;

energy storage means disconnectably connected to said charging means of said external means via the physical connection so that the storage means may be charged by the charging means via the physical connection;

switch means operable selectively to connect the storage means to the fuse means;

a receiver for receiving a radiated electromagnetic fire command signal transmitted by said remote transmitter;

variable delay time means for providing a delay time between reception of the fire command signal and operation of the switch means, said variable delay time means including first and second inputs and an output;

the first input of the variable delay time means being disconnectably connectable to the delay time programming means via the physical connection so that the delay time means may be programmed by loading delay time data from the programming means into the delay time means via the physical connection;

the second input of the variable delay time means being connected to the receiver so that the receiver may activate the delay time means; and

the output of the variable delay time means being connected to the switch means to connect the energy storage means to the fuse means, the programmed delay time after reception of the fire command signal, thereby to energize the fuse means.

2. A detonator as claimed in claim 1 wherein the connector means comprises a first connector and a second connector, the first connector being connected to the energy storage means of the detonator and being disconnectably connectable to the electrical energy charging means of the external means and the second connector being connected to the first input of the delay time means and being disconnectably connectable to the delay time programming means.

3. A detonator as claimed in claim 2 wherein the first and second connectors are ganged to form a single connector.

4. A detonator as claimed in claim 1 comprising a command discriminator connected to an output of the receiver;

and discharging means connected to the energy storage means, the command discriminator being adapted to distinguish transmitted fire and disarm command signals and upon reception of the disarm command signal to cause the energy storage means to be discharged through the discharging means.

5. A detonator as claimed in claim 4 wherein the discharging means is disconnectably connectable via the physical connection to an external discharge command generator forming part of the external means so that a discharge command signal may be communicated to the discharging means via the physical connection, thereby to discharge the energy storage means through the discharging means.

6. A detonator system comprising:

at least one electronic detonator;

each detonator comprising;

fuse means;

energy storage means selectively electrically connectable to the fuse means;

a receiver for receiving a radiated electromagnetic fire command signal;

switch means which is responsive to the receiver and operable to connect the energy storage means to the fuse means after reception of the fire command signal thereby to energize the fuse means;

programmable delay time means for providing a predetermined delay time between reception of the fire command signal and operation of the switch means;

means external of the at least one electronic detonator disconnectably connectable to a selected detonator so that when connected, a physical connection is established exclusively between the external means and the selected detonator;

the external means comprising;

charging means for charging the energy storage means of the selected detonator so that the energy storage means of the selected detonator is chargeable via the connection;

delay time programming means which is disconnectably connectable to the delay time means of the selected detonator via the connection so that the delay time means of the selected detonator may be programmed by loading delay time data from the programming means into the delay time means of the selected detonator via the connection.

7. A detonator system as claimed in claim 6 wherein the charging means for charging the energy storage means and the delay time programming means are housed in a single transportable housing.

8. A detonator system as claimed in claim 7 wherein the energy storage means is connected to a first connector, the delay time means to a second connector, the external charging means to a third connector and the delay time programming means to a fourth connector and wherein the physical connection is established by connecting the first and second connectors to the third and fourth connectors, respectively.

9. A detonator system as claimed in claim 6 comprising a transmitter external of the at least one detonator for transmitting the electromagnetic fire command signal.

10. A method of detonating explosive charges located at a blast site from a remote control station by means of a detonator system, the detonator system comprising at least one detonator;

each detonator including fuse means, energy storage means and a receiver for reception of a radiated electromagnetic fire command signal;

the system further comprising a transmitter external of the at least one detonator; and

charging means external of the at least one detonator for charging the energy storage means;

the method comprising the steps of;

positioning a detonator at the blast site adjacent an explosive charge;

connecting at the blast site the charging means to the energy storage means of the positioned detonator to provide a physical connection extending between the charging means and said energy storage means, for charging the storage means;

charging the storage means;

disconnecting the charging means;

evacuating the blast site;

transmitting from the remote control station by means of the external transmitter a fire command signal;

receiving the fire command signal at the receiver of the positioned detonator; and

causing the energy storage means of the positioned detonator to energize the fuse means of said detonator after reception of the fire command signal thereby to cause the charge to explode.

11. A method as claimed in claim 10 wherein, before the fire command signal is transmitted, there are included the steps of:

connecting external delay time programming means to programmable delay time means in the detonator, programming the delay time means by loading delay time data from the programming means into the delay time means, and disconnecting the programming means; and

wherein the energy storage means is caused to energize the fuse means the programmed delay time after reception of the fire command signal.

12. A method as claimed in claim 11 wherein the method further comprises:

positioning a detonator adjacent each of a plurality of spaced explosive charges;

charging the storage means of each of the detonators; and

programming the delay time means of each of the detonators to detonate the spaced charges in time delay sequence.