US2160313A - Wire joint, especially for electrical shot-firing outfits or similar provisional electrical circuits - Google Patents

Description

May 30, 1939. w NQRRES 2,160,313

WIRE JOINT, ESPECIALLY FOR ELECTRICAL SHOT-FIRING OUTFITS 0R SIMILAR PROVISIONAL ELECTRICAL CIRCUITS Filed March 6, 1937 d H 7191] 7 F119. 2 fi I ONDUCT/IVG L/A/l/YG cououcrma Imma- CONDUC TING L/N //1 veal-or: wa, N0 RRE S Patented May 30,, 1939 PATENT OFFICE WIRE JOINT, ESPECIALLY FOR ELECTRICAL SHOT-FIRING OUTFITS OR SIMILAR PRO- VISIONAL ELECTRICAL CIRCUITS Wilhelm Nor-res, Dorsten, Germany Application March 6, 1937, Serial No. 129,331 In'Germany March 12, 1936 3 Claims.

This invention relates to wire-joints and more especially. to wire-joints to be used with advantage in electrical shot-firing outfits or similar provisional electrical circuits and the like.

In electrical shot-firing outfits, especially when used below ground, a careful mounting of the fil four requirements.

. outfit and especially of the ignition-circuit thereof is of considerable importance. In outfits of this kind frequently a greater number of shots has to be fired simultaneously and in consequence thereof an appropriate number of connections and wire-joints will be necessary. Each of these connections or wire-joints, moreover, has to ful- In the first place there must be a good contact in the wire-joint to avoid an undue resistance at the contact points and unfavorable conditions resulting therefrom with regard to the total resistance of the ignition circuit including the shot-firing fuses forming part of the outfit. Furthermore, the wire-joints must be of sufiicient mechanical strength to prevent separation of the wires by a pull which may occasionally be exerted thereunto. Also, the wires connected by the joint must be completely insulated towards the outside, as otherwise a shunt to said wires may eventually arise or some current source other than that of the ignition circuit may act on said fuses. Finally, the connection between the wires should permit of being made in a simple manner and within the shortest possible time. Moreover, the wire-joint at the same time must comply with all four of these requirements, of which the last-mentioned is most essential, especially in shot-firing outfits working below ground.

By my invention all of the aforesaid requirements are fully and successfully complied with. According to my invention the wire-joints for shot-firing outfits or similar provisional electrical circuits are made by inserting the bare ends of the wires to be connected with each other into an insulating bushing closed at one end thereof and provided with an interior lining of conducting material, and thereupon said bushing together with said lining and the bare end of the wires inserted thereinto is sharply bentto provide a firm and reliable joint to be easily and conveniently made by hand without the use of any implement, such as pliers. Moreover, as the bare ends of the wires to be connected with eachother are inserted into the lining of the bushing as far as to the bottom thereof, eventually also some part of the insulating covering of the wires may thus enter said lining or bushing. In spite of this the bare ends of the wires will be safely secured in position, and a good insulation of the joint as a whole may readily be attained with certainty according to my invention by sharply bending said bushing together with said lining and the ends of the wires therein. In this manner there will also be attained a good electrical joint between the two wires on account of said conducting lining. 'In addition to this, the wire-joint will be of great mechanical strength and especially able to withstand tensile strains imposed thereon. The wires may immediately again be disconnected by straightening out said bushing, the bare Wire ends now being in condition. ready for making some other connection, for instance, by inserting the same into another wire-joint.

It is well known in electrical work to connect two conductors or wires with eachother by inserting the same in opposite directionsintoasmall metal tube insulated at the outside and to twist this tube with the wires therein by means of a suitable implement, such as pliers or by bending said tube and wires into wave-shape. A wire-joint of this kind, however, is rather destined for making permanent connections and, therefore, not suitable for the quick making of ignition-circuits for shot-firing outfits to be laid provisionally below ground. The reason for this consists therein that this known joint or connection must be made very carefully and consequently requires a considerable amount of time. Moreover, when using this known joint, there will be the possibility that the two wires inserted into the tube may project at one or both bare ends out of the tube with the result, that the joint will be not insulated at the projecting end or ends of the wires. The use of a tool for making the joint, moreover, is inconvenient and in addition to this, the tool may easily be lost, especially when working below ground. On the other hand, by connecting the wires by means of the aforementioned bushing closed at one end thereof, in accordance with this invention and by sharply bending said bushing the so obtained wire-joint is in every respect superior to known joints and at the same time of greater simplicity with regard to making and breaking the connection. Moreover, the joint which forms part of my invention is especially suitable for work below ground. In order to lay ignition circuits for shot-firing outfits at very wet places, for instance, when blasting in water, the insulating effect of the wire-joint may be further increased by using the aforedescribed bushings with a filling of soft or plastical insulating material consisting, for instance, of a tar-like mass, Vaseline, or the like.

A filling of this kind, moreover, does not run out of the bushing either during handling or during transport. When inserting the ends of the wires to be connected with eachother into said bushing and sharply bending the latter, said filling will protrude from the orifice of said bushing and this will safely prevent access of water to the bare ends of the wires in the joint, even if the joint is for some longer time kept in water.

During sharply bending the bushing with the ends of thewires therein, said filling of insulating material will be forced out of said bushing, while at the same time the bare ends of the wires will be pressed against eachother and against said 5 conducting lining to provide an intimate contact between the wires, the filling material preventing in no way a good electrical joint between the wires. A

In the accompanying drawing, I have shown some examples of construction of my novel wirejoint, Figs, 1 and 2 being a longitudinal section of the aforesaid bushing and lining in straight condition, Figs. 3 and 4 showing said bushing and lining together with the wire-ends therein in completed, that is bent, condition of the joint,

and Fig. 5 a diagram showing an electrical shotfiring outfit including wire-joints according to my invention.

As shown in Fig. 1 my novel wire-joint consists 0 of a bushing a of insulating material, said bushing being closed at one end thereof and comprising a tube or lining b of conduction material provided in the interior of said bushing a, the end a of the insulating bushing projecting be- 5 yond said tube or lining b. In order to make the joint the bare ends ofv the wires 0 and d to be connected with each other are inserted together with'the ends of their insulating covering into said tube or lining b and thereupon said 0 bushing a, together with said lining b and the ends of the wires c and d therein, is sharply bent in the manner indicated in Fig. 3.

i The insulating material used for the bushing a is a material which may be bent into a different shape and then holds its shape, and such that 5 bushing 0. together with the lining b and the wires 0 and d therein is likewise sharply bent to produce a conducting and strong connection between the two wires 0 and d. In the present case, the ends of the two wires are also firmly surrounded by the conducting lining b, thus securing a good electrical joint even in case the bare ends of the wires are not in full and immediate con- ,tact with each other. Moreover, this form of joint is likewise suitable to resist against a pull 5 exerted onto the two wires interrupting the connection and even in case of a strong pull connection will be maintained in contradistinction to the aforementioned wire-joint made by twisting. The construction of the wire-joint shown' in Fig. 2,

7 according to which one wire is fixedly connected to the. conducting lining b, is possessed of the further advantage, that the shot-firing fuse connected to the wires 0 and a may be protected during installing the outfit against being acted 75 upon by a current source by having also the bare end of the wire 0 inserted into the bushing a. In the manner indicated, there may also be attained a good and firm electrical joint between wires of different diameters by winding the bare ends of the wire of smaller diameter around the bare end of the wire of larger diameter and thereupon inserting both wire ends into the bushing and sharply bending the same as indicated in Fig. 4. I

In Fig. 6 I have shown an electrical shotfiring outfit comprising several fuses placed in the ground and connected in series with each other by means of wires and wire-joints a}, a a and a. The circuit including said fuses in series is connected to the ignition wires e and f eventually with insertion of a surplus of wire g. From the foregoing explanations and especially from Fig. 5 of the drawing it may be seen that wire-joints constructed according to my present invention are of great importance in connection with provisionally installed ignitioncircuits forming part of shot-firing outfits, said wire-joints making it possible to establish a good, well-insulated and mechanically strong electrical joint between wires without the use of any, tool. A further advantage consists therein that the wire-joints made ,at the ends of the ignitioncircuit or at the ends of said surplus of wire g may conveniently'be disconnected, at the same time retaining the bare wire-ends in condition to be used for making further connections. Disconnection of the wires may solely be attained by straightening out the bent bushing a and withdrawing therefrom the ends of the wires, which may likewise be done without the use of any tool.

I claim:

1. A wire joint for connecting wires of electrical ignition circuits for shot-firing outfits or similar provisional electrical circuita'said joint comprising a tubular shaped bushing of insulating material, a pair of insulated wires having their ends free of insulation and exposed, engaging the open end of the bushing, only the insulated. parts of the wires protruding from the bushing, and a conducting lining interiorly of said bushing and contacting with said exposed uninsulated ends of said wires, said bushing together with said conducting lining being sharply bent, with the ends of the bushing adjacent each other, to remain in the position to which the bushing was bent.

2. A wire joint for connecting wires of electrical ignition circuits for shot-firing outfits or end, a pair of insulated wires having their ends free of insulation and exposed, engaging the open end of the bushing so that only the insulated parts of the wires protrude from the bushing, and a conducting lining interiorly of said bushingand contacting with said exposed uninsulated ends of said wires, one of the wires being fixedly connected with said conducting lining, and the other wire inserted thereinto, said bushing together with said conducting lining and said other wire therein being sharply bent, with the two ends of the bushing adjacent each other, to remain in the position to which the bushing was bent.

3. A wire joint for connecting wires of electrical ignition circuits for shot-firing outfits or similar provisional electrical circuits, said joint comprising a bushin g\ of insulating material closed at one end thereof and open at the other end, a pair of insulatedwires having their ends conducting lining being sharply bent so that the two ends of the bushing are adjacent each othef and remain in the position in which the bushing was bent, and a plastical insulating material filling said bushing to prevent conducting materials from entering the bushing and contacting 5 with the exposed ends of the wires.

WILHELM NORRES

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