OA13001A

OA13001A - Pyrotechnical firing installation.

Info

Publication number: OA13001A
Application number: OA1200500027A
Authority: OA
Inventors: Thierry Bernard
Original assignee: Chemical Holdings Int Ltd
Priority date: 2002-08-01
Filing date: 2003-07-28
Publication date: 2006-10-13
Also published as: US20060086278A1; BR0313356A; PE20040151A1; ZA200501632B; EP1546643A1; CA2494507A1; AP1720A; AU2003247006A1; WO2004013564A1; FR2843191A1; FR2843191B1; AP2005003241A0; NZ538410A

Abstract

A pyrotechnical firing installation comprises a plurality of detonators (3, 4), each with an electric cable (5, 6) comprising at least two connection conductors, and a surface line to which is connected the cable of the detonator. The surface line is formed by sections. Every section comprises a terminal or end part (5a, 6a) of the electric cable (5, 6) coming from a detonator (3, 4) and an end connector (7, 8) to electrically connect this terminal part (5a, 6a) to the cable of the next detonator, at a point of the latter defining the origin of its terminal part.

Description

013001 -1-

PYROTECHNICAL FIRING INSTALLATION

BACKGRQUND OF THE INVENTION

In mines and quarries the breaking of rocks is carried out by means ofexplosives. A firing program consists of making a plurality of drill-hoies in the rock,which are filled with explosives with, for every driil-hole, a detonator thatpermits the firing. Some of these detonators are electronically controiled,which makes it possible to program the setting off of the explosionsaccording to a predetermined firing plan.

The execution of a firing plan consists, therefore, after having arranged ailthe detonators in the drill-hoies that hâve been made and connecting themto a control unit or firing box, of identifying every detonator by a serialnumber and applying to it a delay time which will détermine the moment ofignition of the charge in relation to a general firing signal.

Electronic detonator Systems receive power and control signais from a busor surface line, connected to the firing box and extending over the firingrange so as to connect ail the detonators. A detonator generally comprises an elecfronic module in the forrn of atubular sheath, one end of which is provided to receive the pyrotechnicalblasting cap. From the other end of this tubular sheath there exits anelectric cable with a length roughly equal to the drilling depth of the drill-hoies. The end of this cable carries connection means such as, for 01300 1 -2- example, clips that make it possible to connect each of the wires, withoutbaring them, to the two-wire line running over the firing range.

The putting into position of the ground bus or surface line of the firing rangeis a very inconvénient operation. Furthermorë, the connection of each ofthe detonators to this line requires spécial attention and créâtes a risk of 5 errors.

SUMMARY OF THE INVENTION

The présent invention aims to remedy tbese drawbacks mentioned aboveby doing away with the two-wire bus so that every detonator is equippedwith only one cable for its connection to the programming and firing controlmeans and to the other detonators of the firing plan.

To this end, the invention accordingly relates to a pyrotechnical firinginstallation comprising a plurality of detonators each with an electric cablecomprising at least two conductors, and a surface line to which the cable ofeach detonator is connected, wherein the surface line is formed bysections, every section comprising a terminal or end part of the electriccable coming from a detonator and an end connector to electrically connect T., this terminai part to the cable of the next detonator at a point of the latter defining the origin of its terminal part.

In this way, the bus or surface line is formed as the detonators areconnected to one another. It, therefore, is no longer necessary to use aspécial cable for forming the bus. Moreover, the conhector permits theconnection of a first detonator at any place whatsoever of the cable of thenext detonator, so that one can provide a constant connecting cable lengthfor ail the detonators.

The invention also relates to a detonator comprising an electric cable, thefree end of which is provided with a connector for implementing the 01300 1 -3- abovementioned installation, the connector comprising a first part solid withthe end of the cable, provided lateraliy with connection pins and on theopposite side to these pins a pushing wall, and a second part comprising aslide and-a stop wall, into which the first part is mounted movable in relationto the stop wall which faces the connection pins, the wall and the slide 5 defining a seat suitable for receiving an electric cable oriented transversely to the cable equipped with the connector.

Thus, by means of this connector one can produce a latéral connection ofthe end of a cable to any place along the cable of the next detonator.

Other characteristics and advantages of the invention wilî be noted from the lu description given below by way of non-limitative example, of an exemplified embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS Référencé will be made to the attached drawings, wherein:

Figure 1 is a diagram illustrating a pyrotechnical firinginstallation according to the invention;

Figures 2, 3 and 4 illustrate in a front, bottom and top view respectively,one part of a connector according fo the invention;

Figures 5 and 6 illustrate in a front view and a side view a second partof a connector according to the invention; and

Figures 7 and 8 illustrate the coopération of these two parts for theelectrical connection of two successive detonatorcables. 20 01300 1 -4-

DESCRIPTION OF AN EMBODIMENT

The diagram of Figure 1 shows two blast-holes 1 and 2 beionging to a firingplan or program, in which are arranged two detonators 3 and 4, each ofwhich is provided with an electric cable 5, 6 having at leasttwo conductorscoming oui of the respective blast-hole. Each of the cables 5, 6 comprisesat its free end. a respective connector 7, 8. A central control unit or firingbox '9 is equipped with an electric cable 10, the end of which is alsoprovided with a connector 11. The connector 7 at the end of cable 5according to the invention can be mounted on the cable 6 and ensure theelectrical connection of the wires, or of some of them, of the cable 5 andcable 6. The connector 7 is placed on the cable 6 at a point which forms theorigin of the terminal or end part 6a of cable 6. Likewise, the connector 11of the cable 10 defines the termina! or end part 5a of cable 5. In this waythe surface line, with the exception of cable 10, is formed by successivesections, which are the terminal parts 5a, 6a of the cables 5, 6. It will beunderstood that in this way there no longer is a spécial cable dedicated tothe formation of a surface bus for the control and power supply of thedetonators of a firing installation.

Figures 2 to 6 illustrate a spécial embodiment according to the invention ofa connector such as 7, 8 or 11. The illustrated connector comprises a firstpart 20, for example of plastic material overmoulded at one end by a cablesuch as 5, 6 or 10, this first part 20 comprising four latéral pins 21, 22, 23,connected electrically to three conductors 25, 26, 27 of the electric cable,and a terminal 24 connected to a test wire 28. On the opposite side to theconnection pins, the part 20 comprises a push wall 29 prolonged on theopposite side to the cable 5, 6, 10 by a flexible tab 30, which extendsperpendicular to it and is provided with an opening 31 and a terminalgripping part 32. As illustrated, the part 20 has a cylindrical volume 33 inthe extension of the electric cable, a cylindrical volume 34 which isperpendicular to the volume 33 and has roughly the saine diameter, fromone end of which the pins project, whereas at its other end the volume 34 is 013001 -5- connected to the push wall 29, which in turn is connected to the cylindricalvolume 33 by a partition 35.

In Figures 5 and 6, the second part 36 of the connector according to theinvention is shown, which comprises a slide 37 formed by two watts 38 and39 and an end wall 40 perpendicular to these two walls 38, 39. The insideb surface of the wall 40 is connected to the inside surfaces of the walls 38 and 39 by a cylindrical surface congruent with the cylindrical surface of thevolume 34 of the part 20. The distance beiween the walls 38 and 39 ispracticaliy equal to the diamefer of the cylindrical volume 33 of the part 20,whereas in the upper part these walls are provided with at least one insidelü bead 41, 42, which siightly reduces the distance between them, so thaï the inserting from above of the part 20 into the slide 36 requires a small amount of force in order to pass these beads.

The end wall 40 is prolonged under the slide 36 and has a part 43extending from it at a right angle, which forms a stop wall facing the bottomopening of the slide. This stop wall 43 ends in an inclined gripping part 44,and at the point where it connects to the part 40, it has a fillet 45 whichtogether with a bead 46 to the side of fhis fillet 45 forms a partial cradle soas to wedge into the seat formed between the plate 43 and the slide 36 andnear the wall 40, a roughly cylindrical body that will be inserted into it, which “u body has a longitudinal axis extending perpendicularly to both the volume 33 and the volume 34 of the first part 20 when it coopérâtes with thesecond part 36. It will also be noted that there is an opening 43a in theright-angle wall 43, which opening is located just to the right of the place of the slide that receives the body 34 of the part 20. 2b

Finally, it will be noted that there is a lug 47 on the outside surface of theend wall 40, which lug 47 is intended to penetrate into the opening 31 of thetab 30 of part 20.

The two parts of the connector of the invention are assembled in thewaiting position illustrated in Figure 7. In this position the pins 21, 22, 23 0 1300 1 -6- are retracted inside the siide 36 so that one can inseri into the cradle 45, 46a cable 5 or 6, cylindrical but preferabiy having a fiat side 48 (see Figure 8)parallel to the bundle of conductors 25, 28, 27 which ii encloses. When, asin Figure 8, the cable 5, 6 is in position in the cradle, the connection isensured by pushïng on the plate 29, which moves the part 20 towards thestop wall 43 of the part 36, forcing the pins to penetrate into the inside ofthe cable 5, 6 until they reach the bundle of conductor wires. Theconnection position of the two parts 20 and 36 is then locked by thepénétration of the lug 47 into the opening 31.

The spécial shape of the cable 5, 6 illustrated in Figure 8 constitutes alocating device for the putting in place of the connector on a detonatorcable and guarantees a good electrical connection. !t must be mentionedthat in its position illustrated in Figure 7, the connector according to theinvention permits the carrying out of control tests by introducing into thecradle 45, 46 a test probe, which will teel the pins and terminal of the part20 so as to proceed with usage vérifications before the detonatorcorresponding to the connector is connected to the next detonator cable.This probe is introduced into the opening 43a. It will be noted that in thepresence of a cable this opening is closed off, which prohibits anymeasuring tests of a detonator already connected to the firing installation.

Taking into account the shape of the cable and its coopération with theinside surface of the slide 36, the tightness of the connection is ensured.The gripping parts 32 and 44 of the tab 30 and stop plate 43 make itpossible on the one hand to disconnect the pins so as to pull them out ofthe cable and on the other hand to disengage the cable from its seat in thecradle.

Because of the invention it is possible to produce on the ground a run ofrelatively tight wires since the connection of a cable to the next cable canbe made anywhere. In this way one can take into account the differentdistances that separate the blast-holes in a firing plan wiihout the ground being encumbered by a surplus length of electric cables in which the feet ofworkers can become entangled and inopportunely break the connections.

Claims

01300 1 .-7- CLA1MS

1. Pyrotechnical firing installation comprising a plurality of detonators(3, 4), each with an electric cable (5, 6) comprising at least twoconnection conductors, and a surface line to which tbe cable ofeach detonator is connected, characterised in that the surface line isformed by sections, every section comprising a terminal or end part 5 (5a, 6a) of the electric cable (5, 6) coming from a detonator (3, 4) and an end connecter (7, 8) to electricaily connect this terminai part(5a, 6a) to the cable of the next detonator at a point of the latterdefining the origin of its terminal part.
2. Detonator comprising an electric cable, the free end of which is θ provided with a connecter for implementing the installation according to claim 1, characterised in that the connecter comprisesa first part (20) solid with the end of the cable, provided iaterally withconnection pins (21, 22, 23) and on the opposite side to these pinsa pushing wall (29), and a second part (36) comprising a slide (37) ? and a stop wall (43), into which the first part (20) is mounted movable in relation to the stop wall (43) which faces the connectionpins (21, 22, 23), the wall (43) and the slide (37) defining a seatsuitable for receiving an electric cable (5, 6) oriented transversely tothe cable equipped with the connecter. 1
3. Detonator according to claini 2, characterised in that the slide (37)comprises latéral walls (38, 39, 40), perpendicular to the stop wall(43), of which at least one (40) comprises on the oufside holdingmeans (47) of the first part (20) provided to this effect with a flexiblelocking tab (30) approximately perpendicular to the pushing surface(29).
4. Detonator according to any one of the daims 2 and 3, characterisedin that the profile of the section of the electric cable (5, 6) 013001 -8- corresponds with regard to shape to the profile of the seat (45, 46)of the second part (36) of the connector.
5. Detonator according to claim 4, characterised in that the cable (5, 6)has a fiat part (48) and in that the seat has a corresponding fiatsurface passed through by the connection pins (21, 22, 23) of thefirst part (20) of the connector.
6. Detonator according to claim 5, characterised In that the stop wall(43) is provided, opposite the slide (36), with a latéral wedging bead(46) for the cable received in the seat. 8 pages Chemical Holdings Int-» Ltd par procuration