EP0525018B1

EP0525018B1 - Device for disconnectably connecting cable wires

Info

Publication number: EP0525018B1
Application number: EP91907679A
Authority: EP
Inventors: Dieter Fremgen; Dieter Adamaszek; Filip Vandeputte; Jan Vansant
Original assignee: Walter Rose GmbH and Co KG
Current assignee: Walter Rose GmbH and Co KG
Priority date: 1990-04-14
Filing date: 1991-04-12
Publication date: 1996-10-02
Anticipated expiration: 2011-04-12
Also published as: BR9106339A; ATE143749T1; NO923968L; JPH05506123A; CA2079674C; NO307634B1; NO923968D0; CA2079674A1; WO1991016738A1; EP0525018A1; DE69122503T2; JP3101319B2; DE69122503D1

Abstract

A device (1) is described for disconnectably connecting cable wires to a contact plate (2). The contact plate contains a through opening (9) and, in use, one of the cable wires to be contacted is urged into contact with the edges of that opening (9). The cable wire is moved by a thrust piece (3) which also contains a through opening (24) and which is moved relative to the through opening (9) in the contact plate by means of a screw element.

Description

This invention relates to a device for disconnectably connecting cable wires to a contact plate, and particularly to such a device designed to engage two different cable wires in a housing of electrically non-conductive material, preferably plastics material, wherein one of the cable wires to be contacted can be brought into contact with the contact plate, preferably, by means of a screw element.
An electrical contacting device for connecting cable wires is known, for example, from EP-0 315 345-A2. In the known device, contact plates are provided in pairs in a plastics housing. The contact plates have metal slots on both sides which, are in the form of cutting blades, and are thus able to cut through the insulating jacket of the cable wire to be contacted and clamp the metallic conductor inside them. An electrical connection is thus made by means of this contact plate between the two contacted cable wires. If one of the cable wires has been pre-installed, for example at the factory, the idea of such devices is to insert the cable wire to be connected and press it by means of a thrust element between the cutting blades in the contact plate. In the known solution, this is achieved by means of a cap screw with the aid of which cable wires are pressed in pairs into contact plates arranged in pairs.
The known solution has a number of advantages, but does involve some disadvantages. As examples the following may be mentioned.

(1) The contacting mechanism is relatively complicated in that, in order to press the cable wire between the cutting blades, the cover of the device has, in practice, to be moved.
(2) Testing of whether the cable wires have been contacted or not can be carried out only with difficulty.
(3) A particular drawback is that, once a cable wire has been pressed in between the cutting blades of the contact plate, it is very difficult, if not impossible, to release and withdraw the cable wire so contacted, for example if it has not been installed correctly. In order to do this, it is necessary to unscrew the entire lid so that the contacted cable wire can be lifted out using a tool.

DE-A-3216096 discloses a terminal block for telecommunications cable leads which has an electrically conductive screw terminal, mounted in an insulating case. For automatic penetration of the insulation by tensioning the screw terminal, the latter is formed from a contact bridge fixed to the base of the insulating case and from a pressure clamp covering this, which can be displaced by a pressure screw which is fixed in the insulating case in the axial direction but can be rotated with respect to the contact bridge. Both the contact bridge and the pressure clamp have inlet apertures in their legs, which are tangential to one another, with slits continued in the displacement direction and with these slits running in opposite directions in two legs which are tangential to one another.
An object of the present invention is to provide a solution which simplifies construction, and which renders possible both testing for contacting and easy removal of a cable wire once contacted should the cable wire have to be replaced.
The present invention provides a device for disconnectably contacting and connecting two different cable wires, the device comprising:

(a): a contact plate provided with a first through opening and a second opening comprising a slot, to receive the cable wires;
(b): a thrust piece which surrounds at least part of the contact plate and which is longitudinally displaceable thereover, wherein the thrust piece is also provided with a through opening corresponding to, and movable relative to, the first through opening in the contact plate; and
(c): a screw threaded element by means of which a said cable wire may be brought into contact with the contact plate in the first through opening therein, characterised in that:
(d): the first through opening is disposed longitudinally above the second opening;
(e): the contact plate is provided with a sheet metal vane which is integral with the contact plate and has toothed outer edges with which the screw threaded element engages; and
(f): the second through opening in the thrust piece corresponds to only the first through opening in the contact plate and is movable relative to the first through opening in the contact plate by screwing the screw threaded insert on the toothed outer edges of the vane of the contact plate.

Preferably the device is mounted in a housing of electrically non conductive material.
Preferably the contact plate is secured non displaceably in the housing.
The invention provides a number of advantages compared to the known solution described above. For example it is possible to use simple components, for example rotationally symmetrical components. The through openings in the thrust piece can be used not only for contacting, but also for releasing a cable wire once contacted. This is described in detail hereinafter. The force to be applied in contacting can be controlled in a simple manner, and so on.
Further advantages of the invention are apparent in preferred embodiments of the invention which are described hereinafter.
For example testing means may be provided to check the electrical contact made. In one embodiment a test vane is provided integrally, but at an angle to the contact plate. Alternatively one region of the contact plate itself can be used for testing, in which case test bores may be made in parts, for example in screw elements, that are provided electrically connected to the contact plate.
In order to fix the plate spatially in a simple manner, the contact plate is preferably provided with locking elements to secure the contact plate in the particular receiving housing.
The locking elements are preferably splayed outward in the same plane or folded over at right angles during installation.
By providing the thrust piece with a through opening, it is equipped not only with a thrust surface (to urge the cable wire into contact with the contact place), but by reversing the movement (preferably screwing movement) which effected the contact, it is possible to lift a wire that has been pressed into contact, out of contact, thereby releasing the wire.
The contact plate comprises a sheet metal vane having toothed outer edges. These toothed edges preferably project through longitudinal slits in a guide cylinder which is provided on, or extends from the thrust piece. Preferably a threaded insert element, eg a threaded cap is provided which has an internal thread arranged to slide over the guide cylinder and to engage the toothed outer edges of the contact vane. Thus the guide cylinder, together with the thrust piece, can act as a plunger which can be moved downward and upward relative to the contact plate, for example by turning the threaded element.
The through opening in the thrust piece is preferably substantially similar in shape and size to the through opening in the contact plate. In use, before insertion of a cable wire, the through opening provided in the thrust piece is positioned in register with the through opening in the contact plate. Then a cable wire is inserted into the in-register through openings. Finally the through opening in the thrust piece is moved (preferably downwards) relative to the through opening in the contact plate. This can be done by screwing the threaded insert onto the toothed edges of the contact plate. This relative motion of the through openings in the thrust piece and the contact plate causes edges (preferably the upper edges) of the through opening in the thrust piece to force the cable wire against edges (preferably the lower edges) of the through opening in the contact plate, thereby cutting through any insulation on the cable wire to contact the conductor within.
If it is desired, later, to withdraw the inserted cable wire, the through openings in the contact plate and the thrust piece are simply moved back into register, for example in the first and second preferred embodiments, by unscrewing the relative threaded elements, causing the lower through opening in the thrust piece to lift the cable wire upwards from its engagement with the contact plate, thus allowing easy withdrawal. This arrangement minimises the possibility of the insulation of the cable wire being trapped by the edges of the contact plate if the cable wire is withdrawn. Thus the through opening in the thrust piece can act both to force the wire into contact with the contact plate, and to release the wire from the contact plate for withdrawal.
It should be noted that all references to upwards, downwards, upper, lower, vertical and the like are used for convenience. They indicate only the relative positions of the component pans of the device.
The through opening in the thrust piece may be provided in a number of configurations. In one embodiment it is provided as a bore through a solid end of the thrust piece. In this case, it acts on the wire on both sides of the contact plate. In a preferred embodiment, the through opening in the thrust piece is provided as an aperture in a substantially planar projection at one end of the thrust piece. In this case the aperture in the projection is preferably arranged, in use, to be only behind the corresponding through opening in the contact plate (the word behind being used in relation to the direction of insertion of the cable wire). This arrangement has a number of advantages. For example, it minimises the possibility of the core insulation being trapped within the device if a cable wire is withdrawn. Also it allows easy entry of insulating sealing material, such as gel, around the contacted wire, as described hereinafter.
The thrust piece is preferably also equipped with longitudinal guides so it can slide within a housing in the axial direction but cannot rotate.
Where the through opening is in a plate extending from one end of the plunger on one side only (preferably behind) the contact plate, the longitudinal guides on the thrust piece are preferably arranged such that the thrust piece can only be inserted into the device housing in one onentation, viz so that the through opening at the end of the plunger is correctly positioned.
The guides on the thrust piece may be channels or ridges, on its outer surface, which mate with corresponding ridges or channels on the inside of the bore of the housing.
In the first preferred embodiment described above, comprising a guide cylinder and a threaded insert, the thrust piece is preferably provided with an outwardly pointing annular projection at its upper edge towards the guide cylinder, and the threaded insert (fitted over the guide cylinder) is preferably provided with an outwardly pointing annular projection at its lower edge towards the thrust piece. A split clamping ring is then preferably positioned over the annular projections. The plunger and the threaded insert are thus connected to each other so as to be rotatable relative to each other but to be fixed relative to each other in the axial direction. This arrangement facilitates mounting and simplifies manufacture. The thrust piece can be guided to slide in the housing.
In one embodiment the split clamping ring comprises a C-shape ring, which is sufficiently resilient to allow the arms of the C to be opened and the ring sprung into position around the outwardly pointing annular projections on the upper edge of the thrust piece, and the lower edge of the threaded insert. In another embodiment the split clamping ring comprises two separate or hinged half shells which can be opened to position the ring around the annular projections, and then closed and held in a closed position by a mechanical retaining means, such as a clip or the like. The latter embodiment is preferred because it avoids the risk of the clamping ring springing open during axial motion of the threaded insert and the plunger.
The device may also comprise a cap having a blind bore which, for example, in the first preferred embodiment, described above, can be fitted over the threaded insert so that rotation between the cap and the insert is prevented. The cap preferably comprises an electrically non-conductive material. Preferably the cap is provided with a screw head so that a screw driver can be used to tum the cap and hence the threaded insert. A screw head with a blind bore, can also be provided in other embodiments.
A resilient element, such as a spring, is preferably also provided between (i) whatever element is moved to act on the thrust piece, and (ii) the thrust piece. For example, in the first preferred embodiment, where advantageously a cap is included, the resilient element is preferably arranged so that it is compressed between (i) the cap (and/or the threaded insert) and (ii) the guide cylinder, when the threaded insert is turned to move the through openings in the contact plate and the thrust piece relative to each other. In one embodiment the resilient element is compressed between the blind end of the cap and the free end (upper end) of the guide cylinder. In another embodiment the guide cylinder has an end portion of smaller cross-section than the remainder of the guide cylinder, so that it presents a shoulder. In this case the resilient element is preferably in the form of a helical spring which fits around the end portion of smaller cross-section of the guide cylinder. The resilient element, in this case is thus compressed between (i) the cap and (ii) the shoulder on the guide cylinder.
One purpose of the resilient member in the cap is to exert a continual force on the guide cylinder and hence onto the thrust piece, and, in use, an inserted cable wire. This inter alia compensates for changes of pressure in the contact region which may occur after prolonged use, e.g. due to relaxation of the insulation on the cable wire.
The contact plate is preferably made from metal, especially preferably from copper. Preferably the contact plate is punched from sheet metal.
The contact plate contains a through opening, in the form of an aperture in the contact plate, for receipt of a cable wire. In use the cable wire is forced against an edge of the aperture in the contact plate, causing cable wire to be pinched, and the insulation of the cable wire cut, so that the conductor of the cable wire is in electrical contact with the contact plate. In order to make this easier, the aperture in the contact plate is preferably prism shaped, that is it has straight edges meeting at corners. Preferably the aperture is shaped so that the wire is forced between two straight sides, and then along edges tapering from those straight sides towards each other. Depending on the size of the cable wire, the wire will need to be forced a different distance along those tapered edges of the aperture in order to pierce the insulation and contact the wire.
Over pressure of the wire into the aperture (which would cut the wire as well as the insulation) may be prevented (i) onto large wires, by tightening to a predetermined tension, and (ii) onto small wires by a physical stop. This physical stop may be, for example, contact of the inside end of the thrust piece against shoulders on the contact blade.
For small wires, particularly those with conductors of 0.5mm diameter or smaller, it is desirable, to ensure a good contact, to provide a slot at the base of the aperture in the contact plate. This slot provides sharp edges which will cut into the insulation of the small wire.
In a preferred embodiment, in order to achieve additional fixing and loading of the inserted cable wires, and particularly applicable where the same device is to be used for contacting small wires (conductor diameter 0.5mm or less) as well as large wires, it is preferred that the device includes a further resilient element which exerts a resilient force onto the cable wire which is additional to the force exerted by the thrust piece and the earlier mentioned resilient member in the cap eg. in the first preferred embodiment, the resilient element in the cap. Thus, eg. in the first preferred embodiment, even where the threaded insert has been turned onto the contact plate to its limit, eg until it meets a physical stop, such as the shoulders on the contact plate, the further resilient member continues to exert a force onto the cable wire. This further resilient member acts independently of the above earlier mentioned resilient member eg. the resilient member provided in the cap of the device.
In one preferred embodiment the further resilient member is an elongate shape, eg in the form of a strip, bar or rod. The elongate shape resilient member may comprise a single length, or may be folded-back onto itself, eg in the manner of a hair grip, to form an elongate "V" or "U" shaped further resilient member with a slot through the "arms" of the "V" or "U". The further resilient member is preferably arranged at the base of the thrust member. Where a "V" or ""U" shaped further resilient member is used it is preferably arranged at the base of the thrust piece so that the contact plate can slide between the "arms of the "V" or "U".
In another embodiment the further resilient member such as a helical spring is positioned at the base of the threaded insert. In this case a plate is preferably arranged within the cap which abuts the top of the contact plate and hence provided a stop when the threaded insert has been turned a predetermined distance, which is determined such that in that position the further spring is fully compressed. Thus in both embodiments, for small cables, an additional force is exerted onto the cable wire, independently of any first resilient member within the cap. This additional force is preferably large enough to ensure good contact between the conductor of the cable wire and the contact plate, even if the insulation on the conductor relaxes, but not so large that it cuts through the conductor.
One or more of the guide cylinder, the thrust piece, and the cap, if present, preferably comprise a reinforced polymeric material, eg. a polycarbonate material, especially a glass fibre or glass-ball filled polymeric material.
In a preferred embodiments of the invention the device is equipped with a means for testing that a contact has been made between the contact plate and an inserted cable wire.
In one embodiment including a testing means, the testing means comprises a test contact vane which is electrically connected to, preferably integrally formed with the contact plate. This additional contact vane is preferably arranged in use so that it is folded substantially at a right angle to the plane of the main vane of the contact plate, with this construction the device housing is preferably provided with a corresponding test bore into which the additional test contact vane extends such that testing of whether an electrical contact exists between the contact plate and the inserted cable wire can be carried out by inserting a testing probe into the testing bore.
In another embodiment including a testing means, where the device also comprises a cap of substantially non electrically conductive material positioned over the threaded metal insert (as hereinbefore described), a testing bore is provided into the cap. The bore in the cap is arranged to allow a test probe to be inserted into electrical contact with the threaded insert in the cap, and hence into electrical contact with the contact plate (since the threaded insert is screwed onto the toothed edges of the contact plate). This embodiment avoids the need for a separate contact vane on the metal contact plate, and also avoids the need for a separate test bore in the device housing.
Preferably two or more, more preferably a plurality of contact blades and associated plungers are provided in a common housing.
Preferably, a reservoir for insulating sealing material such as a gel is provided in the housing, especially around the entry regions for the cable or cables. Preferably an overflow space is provided in the housing, to allow for displacement of the gel when a cable wire is inserted.
The functional behaviour of a gel material, in particular its high elongation, means that if the cable wire is withdrawn the gel is dragged back from the overflow space to its sealing position for sealing a newly inserted cable.
Examples of suitable insulating gels are described in US patents 4600261, 4634207, 4595635.
Where a gel is used the contact plate is preferably provided with one or more further apertures to allow easy passage of gel through the contact plate. This ensures that the gel conforms to the surface of the cable wire forming a good seal. and is not hindered in its conformation by the presence of the contact plate.
In a preferred embodiment the case is provided with a flexible lip at the point of entry of the cable wire. This lip serves inter alia to prevent or minimise loss of gel from the housing if a cable wire is withdrawn. As the wire is withdrawn the lip is drawn towards the wire, scraping any residual gel from the surface of the wire insulation as the cable wire is withdrawn.
The housing is preferably also provided with a stop member arranged to limit the distance of insertion of a cable wire.
The invention also provides for the contact elements to be assembled into blocks in a modular design, the individual black modules being so arranged on a mounting plate that the contact opening for the cable wires to be contacted is arranged on one side of the mounting plate whilst the contact plate for the other cable wire contacts, is arranged on the other side of the mounting plate. The contact plate for the other cable wire contacts may be preconnected at the factory, or installed in the field. Where the other cable wire contacts are installed in a factory they may typically be sealed with, for example, a standard potting composition. Where they are installed in the field, they are preferably seated with a gel of the type described hereinbefore.
It may be advantageous to cover the reverse side of the mounting plate with a closure housing which is provided with insulating gel at least in the region of the contact modules. As a development, provision can be made for the mounting plate and the closure housing to be pivotally connected to each other.
The same may be said finally for a closure flap covering the contact plane, which closure flap is pivotally fastened in turn to the mounting plate and/or to the closure housing.
The latter construction makes it possible for the individual planes to be opened at any time by competent persons for work to be carried out, whether it be the plane beneath the mounting plate. for example for the post office or a corresponding authority, or the side above the mounting plate for the end user making a connection.
The invention is described in detail below, by way of example, with reference to the drawings in which:

Fig. 1: is an exploded view of a connection element according to a first embodiment of the invention without housing,
Fig 2: is a section through a housing region with two connection elements.
Fig 3: is a section through part of the housing, perpendicular to the sectional view shown in Fig. 2,
Fig 4: is a three-dimensional view of a housing without base plate,
Fig 5a and 5b: are three-dimensional cross-sectional drawings of a further embodiment of the invention, with the thrust piece lowered in Fig 5a and raised in Fig 5b,
Fig 6a and 6b: are cross-sectional drawings of further embodiments of the invention,
Fig 7a and 7b: are cross-sectional drawings of further embodiments of the invention,
Fig 8: is a plan view of a region of the contact place in accordance with one embodiment of the invention,
Fig 9: is a partial section through a housing in accordance with one embodiment of the invention,
Fig 10: is a section through a plurality of housings having a common connection box,
Fig 11: is a section approximately along the line XI-XI in fig 10.

In the following description, essentially two different possible constructions are described in detail and, as far as possible, functionnatly identical parts bear identical reference numerals. If necessary additionally provided with an "a" in the case of the modified embodiments. For example, the contact element shown in Figures 1 to 3 is generally designated 1 and that shown in Figures 5a and 5b generally 1a.
Referring to the drawings, Figure 1 shows a single contact element, generally designated 1, in a so-called exploded view. Considering the drawing from the bottom to the top, there are shown, a thrust piece 3, a resilient element 4, a split clamping ring 5, a screw element 6 and finally an operating screw head 7 which fits over the screw element.
The contact plate 2 has a lower blade-like slot 8 for cable wires to be contacted in the housing. Connection to slot 8 may be connected in the factory, or in the field. For cable wires that are to be inserted in the field, for connection to those already contacted, or later to be contacted by slot 8, an inner through-opening 9 is provided in the contact plate 2. The through opening 9 is prism shaped having straight sides 9', extending to tapered edges 9" which taper to a point 10. A cable wire (designated 11 in Fig 3) is inserted, in use, into through opening 9.
At its upper end, the contact plate 2 is equipped with a sheet metal vane 12 which is toothed at both outer edges 13, the teeth being adapted to a screw pitch, i.e. two corresponding, substantially mutually opposite teeth exhibit a difference in height that would correspond to a screw turn over a sector of a circle.
In order to be fastened in the plastics housing, which is not shown in Fig 1 but is designated 14 in fig. 2, the contact plate has two opposite, splayed clamping projections 15. A test contact vane 16 is formed on at right angles to the principal plane of the contact plate 2, the tree end 17 of which vane 16 lies, in the mounted position, in the interior of a test bore designated 18 in Figure 4 which in use is filled with an insulating gel. For contacting, a testing probe is passed through the gel onto the free end 17 of the test contact vane 16 so that a corresponding measurement can then be taken.
The thrust piece generally designated 3 has an upper guide cylinder 19 having lateral slots 20 through which the toothed outer edges 13 of the contact plate 2 project in use, as is shown, for example, in Fig 2. In the region of transition between the thrust piece 3 and the guide cylinder 19 which is integrally formed thereon an annular projection 21 is provided. In use, an internal thread, not shown in Fig 1, of a screw element 6 fits over the toothed outer edges 13, in order to create a rotatable, but otherwise fixed, connection between the thrust piece 3 and the screw element 6, the screw element 6 also has an annular projection 22 corresponding to the annular projection 21 on the thrust piece 3, a split clamping ring 5 being arranged over the two annular projections 21 and 22. This may be in the form of a resilient spring C-shaped member, or in the form of mating hatf shells, held together by a mechanical arrangement. The screw element 6 is additionally equipped with an operating screw head 7 provided with an inner blind bore, there being provided between the free end, designated 23, of the guide cylinder 19 and the base 39 of the blind bore in the operating screw head 7 an elastic spring element 4 so as to be able to act in the direction of the contact in the event of variations in the contact pressure, eg due to relaxation of the wire insulation.
Just as the contact plate 2 is provided with a through opening 9 having a prism shaped aperture tapering to a point 10 the thrust piece 3 is also equipped with a corresponding through-opening 24. This may likewise have a tapered aperture 25 which, in use, is in register with the through-opening 9 in the contact plate. In order to prevent the thrust piece 3 from turning with the screwing movement of the screw element 6, lateral guide projections 26 are provided.
The two screw positions (full unscrewed and full screwed) are shown side-by-side in Fig 2. First of all, the plastics housing 14 is equipped with entry apertures 27 corresponding to the number of contact elements 1, as shown in Fig 4. The through-opening 9 in the fixed contact plate 2 which is clamped in the housing 14 is substantially in alignment with these entry apertures 27, the latter being larger, however, to allow relative movement of the inserter cable wire 11. The through-opening 24 in the thrust piece 3 is exactly in alignment with the opening 9 in the contact plate 2 in the insertion position of a cable wire. This position is shown on the right in Fig 2. When the cable wire is then inserted and the screw element 6 is turned by means of the operating screw head 7, the screw element is screwed downward over the toothed outer edges 13 of the fixed contact plate 2 together with the thrust piece 3 in such a manner that an inserted cable wire is squeezed from the top of the through-opening 24 towards the point 10 of the aperture in the contact plate 2. This position is shown on the left if Fig 2.
To open or unmake the contact, the operating screw head 7 is turned in the opposite direction so that the thrust piece 3 is moved upward. Therewith the pinched cable wire is lifted by means of the aperture 24 in the thrust piece away from the point 10 of the aperture 9 in the contact plate 2 and can subsequently be withdrawn from the device.
Figures 5a and 5b shows an alternative embodiment of device according to the invention The thrust piece is lowered in Figure 5a to cause contact, and raised in Fig 5b. This embodiment is similar to that already described with reference to Figures 1 to 4, and like reference numerals are used to indicate like parts in Figures 1 to 4 and Figure 5, with the addition of suffix "a" in Figure 5. Different features in the embodiment of figure 5 are as follows. A testing port 41 is provided in cap 7a. To test whether contact has been made between an inserted cable wire and the contact plate 2a, a test probe is inserted into the test port 41 into electrical contact with the threaded metal insert 6a. The threaded metal insert is in electrical contact with the contact plate 2a, and hence the test probe can be used to check that electrical contact has been made to the contact plate 2a. Also the spring 4a within the cap is a helical spring which lies over a projection 40 extending from the end of guide cylinder 19a. The projection 40 is of smaller cross-section than the remainder of the guide cylinder and thus the spring abuts against the shoulder existing between the projection 40 and the remainder of the guide cylinder 19a. In contrast the spring 4 in the cap 7 described with reference to figures 1-4 was in the form of a resilient rubber ball. The through opening 25 provided at the end of the thrust piece is provided in a substantially planar plate 44, which extends on one side only of the contact plate. The through opening 25, is, as in Figures 1-4, in register with the through opening 9 in the contact plate 2. This arrangement facilitates withdrawal of a cable wire, and also facilitates flow of sealing gel around the cable wire. The contact plate 2 also includes an additional aperture 43 below the through opening 9. This is to make it easier for gel to flow within the housing to conform around the cable wire. A final distinction between this embodiment and that of Figures 1-4 is that an elongate spring 42 comprising a rod folded-back on itself into an elongate "U" shape, in the manner of hair grip, is provided at the bottom of the thrust piece. Even when the thrust piece 3a has been moved downwards (by screwing on insert 6a) so that the internal shoulders 46 of the thrust piece abut and stop against the shoulders 45 of the contact plate 2a the elongate spring 42 can be arranged so that it is resiliently deformed by a wire (even a small wire) in this configuration, so that it continues to exert a downward force on an inserted cable wire. The elongate spring 42 acts independently of the spring 4a in cap 7a. Indeed spring 4a is only effective to provide a constant resilient force when the wire is of such a size that the thrust piece 3a is not stopped against the shoulders 45 of the contact plate.
Figures 6(a and b) and 7(a and b) show alternalive arrangements for providing a continual pressure on a wire, using a spring which acts independently of any spring in the cap. In both figures 6 and 7, the "a" figure illustrates installation of the device onto a small diameter cable wire, and the "b" figure illustrates installation of the device onto a large diameter cable wire. As before, the devices are similar to devices already described, and therefore like reference numerals are used to describe like parts, with an "a" suffix applied for Figures 6 and 7 compared to Figures 1 to 4.
Referring first to Figure 6, the guide cylinder 19 is open at its free end so that the vane 12a of contact plate 2a can pass through it, as shown at 50. Also the shoulders 45 on the contact plate 2 are lowered relative to those in the embodiments of Figures 1-4. A new stop is provided (in place of mating shoulders 45 of the contact plate 2a and internal shoulders 46 of thrust piece 3a). The new stop is provided by a plate 51 and support 52 within the cap which abuts against the top of the cap 7a. In this embodiment the further spring 52 is provided between the annular flange 22 of the threaded insert 6a and the annular flange 21 on the top of thrust piece 3a. When a large diameter cable wire is inserted. (Fig 6b) the cap is turned until the force reaches a certain limit. In this case both the top spring 4 (in the cap 7) and the further spring 52 exert a permanent force on the wire. When a small diameter wire is introduced, (Fig 6a), the cap 7a is turned until it reaches its physical stop position. ie the top of the metal vane 12 of contact plate 2a abuts plate 51, and the support 53 abuts the top of the inside of cap 7. In this position the spring 4a in cap 7a no longer exerts a continuing pressure. However, in this position the further spring 52 is fully compressed and therefore exerts a continuing pressure on the small wire. The continuing pressures are desirable in order to maintain continuing contact with the cable wires even if relaxation of the wires causes a change in pressure in the contact region.
Figures 7a and b are very simlar to Figures 6a and b respectively except that a physical stop is provided by plate 51 abutting against an internal shoulder 54 in the threaded insert 6a.
Figure 8 shows a preferred design of through opening 9 in the contact plate 2. In this design the bottom of the opening opens into a narrow slot 60. This design ensures that for a small diameter cable wire good contact is achieved by the edges 61 of the through opening 9. i.e. those edges between the slot 60 and the main part of the through opening 9. Preferably the slot 60 is between 0.1 and 0.45mm wide, preferably about 0.3 mm wide.
The devices shown in Figures 5 to 7 and the preferred feature of Figure 8 can be used in a housing as shown in Figures 2-4.
Figure 9 illustrates a preferred housing that can be used. It is shown, in section, in conjunction with the device of Figure 5. As before like reference numerals designate like parts. Of particular note are the overflow cavity 62 in the housing 4, for flow of the gel (not shown when a wire 11 is inserted. Also lip 63, on the front of the housing, which acts to maintain the gel in the housing if the wire 11 is withdrawn. Backstop 64 is also provided as part of the housing, to limit the distance of insertion of the wire 11. The single aperture 25 in the plate 44 extending at one end of the thrust piece 3, can also be clearly seen in this figure.
Figs. 10 and 11 show an assembly of several contacting housings 14 constructed in modular form, but the particular configuration shown is merely an example.
Because they are in the form of block modules the contacting housing 14 shown in Figs. 10 and 11 are designated 14'.
In the example shown, the individual block modules 14' are arranged in a housing designated 28 overall, a plurality of block modules 14' being screwed to a mounting ptate 29. This mounting plate 29 divides the housing 28 essentially into two regions, the part comprising the contact openings 27' being arranged on the side designated 30 of the mounting plate, whilst the lower part comprising the contact blades 8 and the insertion slots 31 for the further cable wire 11' is arranged on the side designated 32 of the mounting plate 29.
In addition to the mounting plate 29, the housing 28 has a base plate 33 and a closure housing 34, the individual elements being pivotally attached to one another by an optionally common hinge, as is indicated by broken lines in Fig 10.
In order to provide a reservoir for insulating gel 36 (which is particularly desirable where contact to the blades 8 is to be made in the field rather than in the factory) corresponding projections are incorporated in the base plate 33, as can be seen from the cross-section in Fig 11.
A different arrangement for forming a gel reservoir for gel 36 is shown in Figs 2 and 3. In this case, a single block module is equipped with a bottom closure cap 37.
The described exemplary embodiments of the invention can, of course, be further modified in vanous respects without departing from the basic concept. For example, the contact vane 16 may be angled slightly to provide a large support surtace for a contact point. The corresponding bores 18 for this contact gel may be filled with insulating gel or may be closed mechanically, and so on.

Claims

A device (1) for disconnectably contacting and connecting two different cable wires, the device comprising:
(a) a contact plate (2, 2a) provided with a first through opening (9, 9a) and a second opening comprising a slot (8), to receive the cable wires;

(b) a thrust piece (3, 3a) which surrounds at least part of the contact plate (2, 2a) and which is longitudinally displaceable thereover, wherein the thrust piece (3, 3a) is also provided with a through opening (25, 25a) corresponding to, and movable relative to, the first through opening (9, 9a) in the contact plate (2, 2a); and

(c) a screw threaded element (6, 6a) by means of which a said cable wire may be brought into contact with the contact plate (2, 2a) in the first through opening (9, 9a) therein, characterised in that:

(d) the first through opening (9, 9a) is disposed longitudinally above the second opening (8);

(e) the contact plate (2, 2a) is provided with a sheet metal vane (12) which is integral with the contact plate (2, 2a) and has toothed outer edges (13, 13a) with which the screw threaded element (6, 6a) engages; and

(f) the second through opening (25, 25a) in the thrust piece (3, 3a) corresponds to only the first through opening (9, 9a) in the contact plate (2, 2a) and is movable relative to the first through opening (9, 9a) in the contact (2, 2a) plate by screwing the screw threaded insert on the toothed outer edges (13, 13a) of the vane of the contact plate (2, 2a).
A device (1) according to claim 1 also comprising a housing (14) of electrically non conductive material, the contact plate (2, 2a) preferably being secured non-displaceably in the housing (14, 14a).
A device (1) according to claim 1 or 2, characterised in that:
(i) a guide cylinder (19) is provided on the thrust piece (3, 3a), the guide cylinder having longitudinal slits (2) through which the toothed outer edges (13, 13a) of the contact plate (2, 2a) project; and

(ii) the screw threaded element (6, 6a) fits over the guide cylinder (19) to engage the toothed edges (13, 13a) of the sheet metal vane (12, 12a).
A device according to any preceding claim, wherein an operating screwhead (7, 7a) is provided which can act on the thrust piece, and a resilient element (4, 4a) is also provided between the thrust piece (3, 3a) and operating screw head (7, 7a), so that turning the screw head will move the thrust piece via the resilient member.
A device according to any preceding claim, comprising a further resilient member (42) which acts on an inserted cable wire in the contacting direction independently of any resilient member provided between the thrust piece and the operating screwhead as defined by claim 4, which resilient member preferably exerts a continuing force on an inserted cable wire even after the thrust piece (3, 3a) has been moved relative to the contact plate (2, 2a) to abut and stop against a shoulder on the contact plate (2, 2a).
A device according to any preceding claim wherein the contact plate (2, 2a) comprises an additional through opening to allow passage of sealing material therethrough.
A device according to any preceding claim, wherein the through opening in the contact plate is generally prism shaped such that action of the screw threaded element (6, 6a) forces the wire against two angled straight edges, and the side of the first through opening (9, 9a) in the contact plate against which the wire is forced preferably being provided with a slot, preferably less than 0.45mm in diameter, extending away from the first through opening (9, 9a).
An assembly comprising a housing and a plurality of devices according to claim 1, the contact plates (2, 2a) of which are each arranged in a common housing, a reservoir for insulating gel preferably being assigned within the housing to entry regions for the cable wires.
An assembly comprising a plurality of devices according to any preceding claim, in which the contact plates (2, 2a) are assembled into blocks (14') in a modular design, the individual block modules (14') being so arranged on a mounting plate (29) that the first through openings (9, 9a) in the contact plates (2, 2a) for the cable wires to be inserted in use therethrough are arranged on a first side of the mounting plate (29) whilst the slots (8) in the contact plates (2, 2a) are arranged on the other reverse, side of the mounting plate.
An assembly according to claim 9, characterised in that the reverse side of the mounting plate (29) is covered with a closure housing (33) which is provided with insulating gel (30) at least in the region of the block modules, and/or the mounting plate (29) and the closure housing (33) are pivotally connected to each other and/or the module blocks on the first side of the mounting plate 29 are covered by a hinged closure flap (34).