Connectors for wired networks for detonators

Abstract: There is disclosed and claimed a wired network of electrically operable detonators. The network includes a plurality of wired detonator assemblies each including a detonator. The wired assemblies being connected into the network by connectors 10 each including at least one conductive spigot formation 16 removably receivable in a socket 32 which is at least partially lined with a conductive element 34. In the preferred embodiment each connector 10 includes first and second connector halves 12 and 28. The first and second connector halves each includes a body 14, 30 and part of a commercially available connector. The bodies in use forming a water-tight housing for the mating connector parts.

Description: This invention relates to electronic or electric sequential blasting systems and more particularly to such systems for use in mining operations. The invention relates in particular to connectors for use in systems of the aforementioned kind including wired networks for electronic and electric detonators, hereinafter referred to as electrically operable detonators. Wired networks for electrically operable detonators include a blast box and insulated electricity conductive leading wires extending from the blast box, the leading wires being connected by connecting means to the blast box. Detonators, each including an insulated conductive umbilical cord, are connected via the cords to the leading wire, by means of connecting means. Insulated conductive extension wires or extension pieces may be provided between the detonators or between sections of the leading wire. These extension wires are also connected to the leading wire by connecting means. PRIOR ART In one known system, the connections are made by in situ removing protective sheathes at bare ends of the umbilical cords of the detonators and twisting the bare ends about bare regions in the leading wire, to make ohmic or galvanic contact. This method of connecting the detonators to the leading wire is laborious, time consuming and the system as such may not be safe and reliable enough. In another known system, inductive coupling is utilised. A C-shaped magnetic core with a plurality of windings of the detonator umbilical cord wound thereon, is clipped onto the leading wire. In yet another system a custom made so-called insulation displacement connector (IDC) is used. An IDC includes prongs or teeth capable of piercing the insulation of an embedded conductor to which it is to be connected, to make electrical contact with the conductor. These connectors are cumbersome to use, especially in multi-conductor connections where time and skill are required to ensure that each tooth penetrates to the selected conductor with which contact is required. Furthermore, these connectors are difficult to install, because they have a preferred orientation relative to the wire to which they are to be connected for best results. Document EP-A-0 386 860 discloses an electric blasting system for blasting a plurality of delay type detonating primers 29 connected in parallel with an electric blaster 10 by connecting leg wires 51, 52 of these primers in the serial connection mode. Document GB-A-2 088 148 features an electric connector. Document WO-A-90/01610 discloses arresting means on the body of a first connector half. Document US-A-5 375 524 discloses parallel wiring of detonators and a single cable connection to a detonator; but requires the use of a male jumper, a parallel connector, a cap connector and a series female connector. SUMMARY OF THE INVENTION According to the present invention, a detonator assembly includes: a) a wired, electrically operable detonator; b) a first cable having at least first and second conductors connected at one end thereof to the detonator; c) the first cable being connected at another end thereof to a first connector half having at least first and second terminals; d) a second cable having at least first and second conductors; e) the second cable being connected at one end thereof to a second connector half comprising at least first and second terminals and which are complimentary to the at least first and second terminals of the first connector half and wherein the second cable is connected at another end thereof to the first connector half. According to a preferred embodiment of the present invention, the first and second conductors of the first cable are connected at their one ends to first and second terminals respectively of the detonator; whereby, in use and when the first connector half and second connector half of the assembly are connected to one another, the first terminal of the first connector half cooperates with the second terminal of the second connector half and the second terminal of the first connector half cooperates with the first terminal of the second connector half, so that there is a short circuit between the first and second terminals of the detonator. Also according to the present invention, a wired network of electrically operable detonators includes: a) a plurality of wired detonator assemblies each including a detonator; b) a plurality of first cables each having at least first and second conductors connected at one end thereof to a respective detonator; c) each first cable being connected at the other end thereof to a respective first connector half having a conductive spigot formation and a terminal; d) a plurality of second cables each having at least first and second conductors connected at one end thereof to a respective one of a plurality of second connector halves each comprising a socket, at least partially lined with a conductive element and in which the spigot formation is removeably receivable, and a terminal complimentary to the first connector half terminal and wherein each second cable is connected at the other end thereof to a respective one of the first connector halves; whereby, in use, detonator assemblies may be connected in parallel by appropriate mating of first and second connector halves. Also according to the present invention, a method of wiring electrically operable detonators in a network having a plurality of wired detonator assemblies each including a detonator and comprises the steps of: a) connecting one end of a plurality of first cables each having at least first and second conductors to a respective detonator; b) connecting the other end of each first cable to a respective first connector half having a conductive spigot formation and a terminal; c) connecting one end of a plurality of second cables each having at least first and second conductors to a respective one of a plurality of second connector halves each comprising a socket, at least partially lined with a conductive element and in which the spigot formation is removeably receivable, and a terminal complimentary to the first connector half terminal; d) connecting the other end of each second cable to a respective one of the first halves; and, f) connecting detonator assemblies in parallel by appropriate mating of first and second connector halves. The above and further features of the present invention are set forth in the appended claims. BRIEF DESCRIPTION OF THE ACCOMPANYING DIAGRAMS The invention will now further be described, by way of example only, with reference to the accompanying diagrams wherein: figure 1 is a perspective view, partially broken away and enlarged of first and second connector halves of a first embodiment of a connector according to the invention for use in a wired network of electrically operable detonators; figure 2 is a partial longitudinal section through the connector in figure 1 wherein one half of the connector is mating with another; figure 3 is an elevational view of first and second connector halves of a second embodiment of the connector according to the invention for use in a wired network of electrically operable detonators; figure 4 is a longitudinal section through the connector in figure 3 wherein one connector half of the connector is mating with another; figure 5 is a diagrammatic representation of a detonator assembly according to the invention; figure 6 is a basic diagram illustrating the interconnection of detonator assemblies similar to that of figure 5, to form a wired network of electrically operable detonators; and figure 7 is a basic diagram of another wired network of electrically operable detonators wherein connectors according to the invention are utilized to form the network. DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION A connector for use in a wired network for electronic or electric detonators is generally designated by the reference numeral 10 in figures 1 and 2. The connector 10 includes a commercially available RCA connector which is adapted for the purpose aforesaid as described hereinafter. The connector 10 includes a first connector half 12 including a body 14 of an insulating material. The first connector half further includes a conductive spigot 16 and a coaxially mounted tubular conductive terminal 18 forming part of the aforementioned commercially available RCA connector. The first connector half 12 further includes a sleeve 24 of an insulating material which is formed integrally with the insulating body 14. The sleeve 24 extends coaxially with and beyond the spigot 16 and is resiliently flexible. On an inside wall of the sleeve there is defined an annular recess 26. The connector further includes a second connector half 28 including a body 30 of an insulating material. A unit forming part of the commercially available RCA connector and which unit defines a socket 32 lined with a conductive element 34 and includes a coaxial circular cylindrical conductive terminal 36, is provided on the body 30. The outside diameter of the spigot 16 is smaller than the inside diameter of the lining 34 and the outside diameter of the terminal 36 is smaller than the inside diameter of the tubular terminal 18, so that the spigot 16 is a tight fit in the lined socket and the terminal 36 is a tight fit in the tubular terminal 18. On the outside of body 30 there is provided an annular rib 42. To make a connection utilizing connector halves 12 and 28, the front end of the connector half 28 is inserted into sleeve 24. As explained hereinbefore, spigot 16 mates with lined socket 32 and terminal 36 mates with terminal 18. Sleeve 24 extends over and sheathes the front end of the body 30. With the spigot 16 and terminal 36 so received, rib 42 is also received in recess 26 by a positive clip action, to arrest the body 14 and the body 30 together, when the connection is made. The bodies 14 and 30, the sleeve 24 and the cooperating rib 42 and recess 26 collectively form a watertight housing for the aforementioned mating components. The connector may be formed by selecting any suitable commercially available connector and by providing it with body parts similar to that described hereinbefore, to form a connector according to the invention, particularly suitable for use in wired networks for detonators. In use, and as shown in figures 1 and 2 and as will be described hereinafter, first conductors 20.1 and 22.1 of cables 20 and 22 are connected to the spigot 16 and second conductors 20.2 and 22.2 of the cables are connected to tubular terminal 18. Furthermore, conductor 40.1 of cable 40 is connected to the element 34 and conductor 40.2 of the cable 40 is connected to the terminal 36. A second embodiment of a connector according to the invention is generally designated by the reference numeral 50 in figures 3 and 4. The connector 50 comprises a first connector half 52 and a second connector half 54. First connector half 52 includes an insulating body 56 and a jack plug part 58 of a commercially available connector including a jack plug and associated socket defining terminal arrangement. The jack plug part 58 provides first and second axially spaced and mutually insulated terminals 60 and 62. In use, conductor 64.1 of cable 64 is connected to terminal 62 and conductor 64.2 of cable 64 is connected to terminal 60. Ribbed formations 66 are provided on body 56 to facilitate handling of the first connector half 52. Locking means in the form of a first thread 68 is provided on a front end of body 56 adjacent jack plug 58. The aforementioned socket defining terminal arrangement 70 of the commercially available jack plug connector is located in a body 72 of an insulating material. The body 72 defines a mouth 75 for receiving the front end of the connector half 52. The socket defining terminal arrangement comprises first and second axially spaced terminal elements 74 and 76 lining a socket 78 in body 72 for receiving jack plug 58 and the front end of body 56. In the socket 78 there is provided a second thread 80 for cooperating with the first thread 68 when the jack is received in socket 78, to lock the first connector half to the second connector half. Ribs 82 on the second half 54 facilitate handling of the second connector half. In use, first conductors 84. 1 and 86. 1 of cables 84 and 86 are connected to the first terminal element 74 and second conductors 84.2 and 86.2 of cables 84 and 86 are connected to the second terminal element 76. In figure 5, there is shown a diagrammatic illustration of a detonator assembly 100 according to the invention. The assembly comprises a detonator 102 including a printed circuit board 104 on which electronic circuitry 106 forming part of the detonator is mounted. The circuitry controls the operation of a bridge element 108. A first cable 110 comprising two insulated conductors 110.1 and 110.2 is connected at one end thereof to terminals 111.1 and 111.2 of the detonator arrangement. At the other end of the cable the conductors are connected to connector half 112 which is similar to connector half 12 (shown in figures 1 and 2) in the same way that conductors 20.1 and 20.2 are connected to connector half 12. Thus, conductor 110.1 is connected to the spigot 16 and conductor 110.2 to the tubular terminal 18. A second cable 114 including insulated conductors 114.1 and 114.2 is connected at one end thereof to the terminals of connector half 112 in the same way that conductors 22.1 and 22.2 are connected to connector 12 in figure 1 and figure 2. Thus, conductor 114.1 is connected to the spigot 16 and conductor 114.2 to the tubular terminal 18. At the other end of cable 114, conductors 114.1 and 114.2 are connected to second connector half 116 which is similar to connector half 28 shown in figures 1 and 2. Conductor 1 14. 1 is connected to the sleeve 36 and conductor 114.2 to the tubular element 34. Thus, when the first connector half 112 and the second connector half 116 of the same detonator assembly 100 are engaged with one another, the terminals 111.1 and 111.2 of the detonator arrangement 100 are short-circuited, which increases the safety of the arrangement when not in use, for example during storage and transit. An identification code characteristic of the detonator 102 is electronically stored in a memory arrangement (not shown) of the circuitry 106. The code is used to address the detonators 102 to transmit control signals or delay time data to the detonator from a control box via the wired network. A representation of the code is provided in bar code format on an external surface of the bodies of connector halves 112 and 116, at 113 and 117 respectively. The code may alternatively or in addition be provided in a human discernable form on the body. The fact that the code is also readable otherwise than via the network, facilitates the planning and design of a multi-shot blast utilizing detonator assemblies of the kind described and of the lay-out of the blast site. In use, a wired network of electrically operable detonators is conveniently formed by mating the first connector half 112 of an assembly 100 with the second connector half 116 of an immediately adjacent assembly. Extension wires may also be connected into the network utilizing connectors as herein described and/or defined. Furthermore, the network may also be connected to a blast box and a terminator utilizing connectors as herein defined and/or described. In figure 6 there is shown a wired network 118 of electrically operable detonators 119 comprising detonator arrangements 120.1 and 120.2 which are similar to detonator arrangement 100 described hereinbefore. The only difference between detonator arrangements 120.1 and 120.2 on the one hand and arrangement 100 on the other hand is the configuration of the connectors. In detonator arrangement 100 connectors comprising commercially available RCA connectors are used. In detonator arrangements 120.1 and 120.2 commercially available connectors comprising dual parallel prongs 122 and associated dual parallel socket defining terminal arrangements 124 are utilised. As shown, the connectors according to the invention may also be utilized to connect the network 118 to a blast box 126 and to a terminator 128. In figure 7 there is shown another network configuration wherein connector halves 122 and 124 according to the invention are utilised to connect the umbilical cords 130 and 132 of detonators 134 and 136 respectively to a leading wire 138. It will be appreciated that the connectors according to the invention may be utilised to connect a leading wire to a blast box, to connect extension wires to the leading wire, to connect detonators or detonator assemblies to the leading wire and to connect detonator assemblies to one another.

Claims: A detonator assembly including: a) a wired, electrically operable detonator (102); b) a first cable (110) having at least first (110.1) and second (110.2) conductors connected at one end thereof to the detonator; c) the first cable being connected at another end thereof to a first connector half (112) having at least first (16) and second (18) terminals; d) a second cable (114) having at least first (114.1) and second (114.2) conductors; e) the second cable being connected at one end thereof to a second connector half (116) comprising at least first (36) and second (34) terminals and which are complimentary to the at least first and second terminals of the first connector half characterised in that f) the second cable (114) is connected at another end thereof to the first connector half (112). A detonator assembly as claimed in claim 1 and further characterised in that the first (110.1) and second (110.2) conductors of the first cable (110) are connected at their one ends to first (111.1) and second (111.2) terminals respectively of the detonator (102); whereby, in use and when the first connector half (112) and second connector half (116) of the assembly (100) are connected to one another, the first terminal (16) of the first connector half cooperates with the second terminal (34) of the second connector half and the second terminal (18) of the first connector half cooperates with the first terminal (36) of the second connector half, so that there is a short circuit between the first and second terminals of the detonator. A detonator assembly as claimed in claim 1 or claim 2, and further characterised in that the second connector half (116) includes a jack plug, wherein the first (36) and second terminals (32) of the second connector half are axially spaced from one another on the plug and the first connector half (112) defines a complementary socket for the plug, wherein the first (16) and second terminals (18) of the first connector half are axially spaced within the socket. A detonator assembly as claimed in claim 1, and further characterised in that the first and second terminals of the first connector half (112) include a spigot (16) and coaxial sleeve (18) of a RCA connector and the first and second terminals of the second connector half (116) include coaxially mounted outer (36) and hollow inner (34) sleeves of the RCA connector. A detonator assembly as claimed in any of claims 1 to 4, and further characterised in that an identification code characteristic of the detonator (102) is electronically stored in electronic circuitry (106) forming part of the detonator and wherein a representation of the code is provided on a body of the first and/or second connector halves (112, 116)in a form wherein it is readable otherwise than via the cables (110, 114) connected to the detonator. A wired network of electrically operable detonators including: a) a plurality of wired detonator assemblies (100, 120.1, 120.2) each including a detonator (102, 119); b) a plurality of first cables (20, 110) each having at least first (20.1, 110.1) and second (20.2, 110.2) conductors connected at one end thereof to a respective detonator; c) each first cable being connected at the other end thereof to a respective first connector half (12,112) having a conductive spigot formation (16) and a terminal (18); d) a plurality of second cables (22, 114) each having at least first (22.1, 114.1) and second (22.2, 114.2) conductors connected at one end thereof to a respective one of a plurality of second connector halves (28, 116) each comprising a socket (32), at least partially lined with a conductive element (34) and in which the spigot formation is removeably receivable, and a terminal (36) complimentary to the first connector half terminal; characterised in that e) each second cable (22, 114) is connected at the other end thereof to a respective one of the first (12,112) connector halves; whereby, in use, detonator assemblies (100, 120.1, 120.2) may be connected in parallel by appropriate mating of first and second (28, 116) connector halves. A network as claimed in claim 6 and further characterised in that the second conductors (22.2, 114.2) of the second cables (22, 114) terminate in a conductive element (34) arranged in a socket (32) to clad side walls of and thereby line the socket. A network as claimed in claim 6 or claim 7 and further characterised in that the first connector half (12, 52, 112) includes a body (14, 56) of an insulating material for holding the at least one spigot formation (16, 58) and the second connector half (28, 54, 116) includes a body (30, 72) of an insulating material defining the socket (32, 78). A network as claimed in any of claims 6 to 8 and further characterised in that the at least one spigot (16, 58) and the socket (32, 78) form part of a commercially available connector (10, 50). A network as claimed in claim 9 and further characterised in that the commercially available connector (10, 50) is any one of a RCA-connector, a jack plug connector, a DIN connector and a BNC connector. A method of wiring electrically operable detonators in a network having a plurality of wired detonator assemblies (100, 120.1, 120.2) each including a detonator (102, 119) and comprising the steps of:- a) connecting one end of a plurality of first cables (20, 110) each having at least first (20.1, 110.1) and second (20.2, 110.2) conductors to a respective detonator; b) connecting the other end of each first cable to a respective first connector half (12, 112) having a conductive spigot formation (16) and a terminal (18); c) connecting one end of a plurality of second cables (22, 114) each having at least first (22.1, 114.1) and second (22.2, 114.2) conductors to a respective one of a plurality of second connector halves (28, 116) each comprising a socket (32), at least partially lined with a conductive element (34) and in which the spigot formation is removeably receivable, and a terminal (36) complimentary to the first connector half terminal; characterised by the steps of: d) connecting the other end of each second cable (22, 114) to a respective one of the first connector halves(12, 112) ; and, e) connecting detonator assemblies (100, 120.1, 120.2) in parallel by appropriate mating of first and second connector halves (12, 112, 28, 116).

Inventors: GLENN OLIVER DAVID, LOMBARD PIERRE, MEYER ERICH NICOL, GLENN, OLIVER DAVID, LOMBARD, PIERRE, MEYER, ERICH NICOL
Applicants: SMI TECHNOLOGY PROPRIETARY LTD, SMI TECHNOLOGY (PROPRIETARY) LIMITED
Application year: 1997
Main classification: F42C19
IPC codes: F42D1