AU617176B2

AU617176B2 - A connector for low energy fuse

Info

Publication number: AU617176B2
Application number: AU35214/89A
Authority: AU
Inventors: Andre Patrick Crane; Jean Luc Curutchet; Wayne Guy Fensham
Original assignee: AECI Ltd
Current assignee: AECI Ltd
Priority date: 1988-06-07
Filing date: 1989-05-25
Publication date: 1991-11-21
Anticipated expiration: 2009-05-25
Also published as: MW2889A1; AU3521489A; NZ229301A; JPH0250096A

Description

4:_AUS~hU4 PATENTS ACT 1952-1973 Form COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE Class: Int. CI: 617176 Application Nuimber: Lodged-, *Complete Specification-Lodged: Accepted: Published: Priority: Related Art: TO BE COMPLETED BY APPLICANT Name of Applicant: Address of Applicant'.

AECI Limited 16th Floor, Office ToWer, Carlton Centre, Commissioner Street, Johannesburq Transvaal, Republic of South Africa CURUCtiTI aean, L~o FENSUAYI Wayne Guiy CRANE, Andre Patrick Actual Inventor, Address for Service: Industrial Property section TI Australia Operation Proprietary Limited 1 Nicholson Street, P.O. Hox 4311 Melbourne, Victoria 3001, Australia Complete Specification for the Invention entitled: "A CONNIECTOR FOR LOW EN~ERGY FUSE" The following statement Is a full description. of this inventioA, ioludIng the best method of performing It known to me I-* 'Note:trhe description Is to I e typed In double spacing, pica typo face, In an area not exceeding 250 mm In depth and 160 mmIn wIdth, o~n tough white paper of good quality and It Is to be Inserted Inside this form.

11710/76-L ii7lo/78-L C' JTii p~UN, Commo~we~Ith~Gq ern,11~nt I'rInWr, C~uiberz, i_ __11_I 2

THIS

fuse, whereby primary fuse to INVENTION relates to a connector for low energy a shock wave may be transmitted from a length of a plurality of lengths of secondary fuse.

In this specification, the term "low energy fuse" means S 5 a length of flexible plastics tubing with at least the interio it 4 of the tubing being lined with an explosive or pyrotechnic I t t coating. Such low energy fuse is also known as a low energy shock tube. Further, the term "shock 1<ave" is to be understood as meaning either a propagating shock front or a propagating deflagrating front.

In accordance with the invention, there is provided a connector for low energy fuse which comprises a slab-like element which has two surfaces that are substantially parallel and which are bounded by at l:,t one side face, there being at least four passages into the element from the or each side face, the passages being internally in communication with each other.

The element may be cuboidal, the surfaces being rectilinear. The element may then have four side faces with two opposed faces being parallel to one another and the other two faces being parallel to one another. At least one passage may _:jl 3 then extend into the element from one face and one other passage may extend into the element from an opposed face. At least one other passage may also extend into the element from an adjacent face. If there are passages on opposite sides thev are preferably staggered.

Preferably, the passages are all substantially rectilinear. Further, the passages may be substantially co-planar.

Still further, one of the passages which may be regarded as an entrance passage may be centrally located in the element, with 10 the other passages, which can be regarded as exit passages being on both sides thereof.

The passages may taper inwardly to facilitate gripping of fuse inserted therein. Insteac, in order to impede withdrawal of an end portion of fuse from one of the passages, gripping S 5 formations may be provided within the passages. In a preferred form, the passages are all internally stepped or have a restriction to limit the extent to which an end of a length of fuse may be inserted therein.

The element may also have a securing means whereby a length of fuse may be secured to the element. In one form, such a securing means may be implemented by means of apertures in the element, through which fuse is looped, in use, so that if the fuse is pulled its end is not easily pulled out of a passage.

I- -4 It will further be appreciated by those skilled in the art, that the number of fuses that may be used in any particua

I

r application may vary, and not all of the exit passages may be used. Thus, if not all the exit passages are used, problems could arise if there are passages which are open to the atmosphere, as then a shock wave will be dissipated. Thus, a closure means may be provided for closing the exit passages (and if desired the entrance passage). Such a closure means may be a set of plugs which are used to close off the mouths of the passages, or rupturable membranes located at the entrances to the passages or internally. In one form, such rupturable membranes may be provided by a thin film over those faces of the element into which the passages open, The element may be of a mouldable material and the element may be manufactured by moulding. Conveniently, the element may be of a synthetic plastics material, 4 The invention is now described, by way of an example, with reference to the accompanying drawings, in which:-

II

Figure 1 shows a three-dimensional view of a connector in accordance with the invention; and Figure 2 shows a sectioned view of the connector of Figure 1.

Referring to the drawings, the connector is designated generally by the reference numeral 10 and comprises an element 12 that is of a suitable synthetic plastics material such as polypropylene or polycarbonate. The connector 10 is Moulded in a suitable mould (not shown).

As seen in Figure 1, the element 12 is slab-like, being rectangular and substantially flat. The element 12 thus has a length and width which are comparable and a thickness that is substantially less. The element 12 has an end face 14 and two side faces 16 and 18. Further, the element 12 has an entrance passage 20 and four exit passages 22 and 24 that are all rectilinear. As seen, the exit passages 22 and 24 extend transversely with respect to the entrance passage 20, with the exit passages 22 being on one side and the exit passages 24 on the other side of the entrance passage 20. Further, the passages 20, 22 and 24 ar' all co-planar so that the exit passages 24 intefsect the entrance passage 20. The exit passages 22 open out in the side face 16 and the exit passages 24 open out in the other side face 18. The passages 20, 22 and 24 all have saw-tooth teeth 26 close to their entrances, to grip tubing of low energy fuse inserted therein. Instead, the passages may taper inwardly. It will be appreciated that the exit passages 22 and 24 are in communication with the entrance pass.je 20. It will also be noted that the passages 20, 22 and 24 are all stepped having a step 28 to limit the extent to which tubing can be inserted into the passages. It will be appreciated that if the tubing of low energy fuse could be irserted right to the end 30 of the entrance passage 20 or right through one of the exit passages 22 or 24 to extend into the entrance passage 20, then communication between the entrance 6passage 20 and the exit passages 22 and 24 will be impeded.

Those skilled- in the art will appreciate that the element 12, instead of being rectangular, could have any other suitable shape.

The faces 14, 16 and 18 are covered with a thin film 32 which is rupturable by the low energy fuse, such that the passages 20, 22 and 24 are kept closed until used and unused passages are also kept closed.

Apertures 34 are provided in the element 12 so that, in use, fuse can be looped through the apertures 34 and their ends are then inserted in the passages, so as to minimise the possibility of the fuses being pulled out of the element 12.

In use, the end of a length of primary fuse (not shown) is looped through one of the apertures 34 and inserted into the entrance passage 20, breaking the film over the entrance to the entrance passage 20. The ends of two or more lengths of secondary fuse are also looped through the apertures 34 and inserted in different ones of the exit passages 22 and/or 24 rupturing the film over these passages, in the process. A shock wave in the primary fuse is then propagated along the entrirce passage 20 and into the exit passages 22 and 24, initiating shock waves in the secondary fuses.

L L 7 By means of the invention a cheap and reliable connector is provided for connecting a plurality of secondary fuses to a primary fuse.

Claims

2. The connector of Claim 1, in which the element is cuboidal, the surfaces are rectilinear and the element has four side faces with two opposed faces being parallel to one another and the other two faces being parallel to one another.
3. The connector of Claim 2, in which at least one passage extends into the element from one face and at least one other passage extends into the element from an opposed face. a o
4. The connector of Claim 2 or 3, in which at least 0 9 0 one passage extends into the element from one face and at least one other passage extends into the element from an adjacent face. a 0 a a a f0 0 The connector of Claim 3 in which there are a S: plurality of passages extending into the element from a face one one side and at least one passage extending into the element from an opposed face on another side and the passages on one side are staggered with respect to the or each passage on the other side. a 00l 10
6. The connector of Claim 2, which has one passage extending into the element from one face and other passages extend into the element from the faces adjacent the said one face.
7. The connector of any one of the preceding claims, in which the passages are linear and substantially co-planar.
8. The connector of any one of the preceding claims, which includes a gripping means for gripping fuse inserted into the passages and holding it therein. 9 The connector of Claim 8, in which the gripping means comprises gripping formations within I the passages. The connector of any one of the preceding claims, in which the passages are each internally stepped said steps causing a restriction to limit the extent to which a length of fuse may be inserted *into a passage.
11. The connector of any one of the preceding claims which has a securing means for securing lengths of fuse to the element. 12, The connector of Claim 11, in which the securing means comprises at least one aperture in the element through which fuse may be looped. i-1 ji -11-
13. The connector of any one of the preceding claims, which includes the closure means for closing the entrances of those passages that are not utilised.
14. The connector of Claim 13, in which the closure means comprises a thin rupturable membrane over the or each face which has a passage. The connector of any one of the preceding claims which has five passages. 16, The connector of any one of the preceding 4 I4 claims in which the element is of a synthetic plastics material.
17. A connector for low energy fuse, substantially as described in the specification with reference to the accompanying drawings. Dated this day of 1991. AECI LIMITED by its Patant Attorney John R Davy 4 r c 4.