GB2070867A - Terminal device for low tension cables, in particular telecommunication cables - Google Patents

Abstract

A terminal device such as a telephone system junction box has a body (10) of insulating material formed by two H-section portions each defining two channels (31, 32) on opposite sides with the H-shaped portions spaced apart to form, on a cable connecting side, a channel (41) for a cable (23). The cable (23) extends from one end of the device along the channel (41) to the other end and is there divided into two bunches of conductors which are led back into the channels (32) to terminate at clamp elements (39) of contacts (35) on the ends of limb portions (28) of the H-shaped portions. The channels (31) receive jumper wires to terminate at clamp elements (39) of contacts (35) at the ends of limb portions (30) of the H-shaped portions. Holders (40) for over-voltage arresters are inserted in pockets (33) in the limb portions (30) and make contact with the contacts (35) and also through contacts (70) with an earthing frame (14). <IMAGE>

Description

SPECIFICATION Terminal device for low tension cables, in particular telecommunication cables The invention relates to a terminal device for low tension cables, in particular telecommunication cables, for connecting the conductors of a cable to jumper wires which are connected to conductors of a further cable, comprising a body of insulating material having a pair of channels which are open to opposite side surfaces, which pair of channels on a first, cable connection side receive the cable conductors, and on a second jumber side receive the jumper wires, and connecting strip contacts disposed in rows along the walls of the channels in the body, which connecting strip contacts extend in strip form from the cable connecting side to the jumper side and at their ends carry clamp elements for, in particular non-stripping, connection to the cable conductors and the jumper wires respectively.

Terminal devices of this kind are used for example injunction boxes of telephone systems, where the conductors at the ends of telecommunication cables which are brought together have to be joined together in a particular relation. Such a junction box has predetermined bays in which the terminal device is disposed, with the associated cable. Between two such devices, which each terminate a respective telecommunication cable, extend strands ofjumper wires which provide for connection between the respective conductors of the two cables. In previously proposed devices of this kind, the cable extended in a non-stripped condition only to the edge region of the device and was secured to an extension portion of the insulating body, which extended beyond the pair of channels.The result of this was that the terminal device was of greater length and the end region thereof was not available for the purposes of connecting the cable conductors and jumper wires. From the above-mentioned end region, the cable conductors, after stripping, were taken individually to the connecting contacts. When performing contacting operations, the terminal device was swung out about the cable fixing position at the end thereof, so that, when the cable conductors were pressed into place, high pressures had to be exerted, which put an unacceptable burden on handling during assembly. For the purposes of fitting the connecting contacts, the channels also had to be of very great length, which made it difficult to handle the device and made it difficult if not impossible to inspect the contact.

According to the invention there is provided a terminal device for low tension cables, for connecting the conductors of a cable to jumper wires which can be connected to conductors of a further cable, comprising a body of insulating material having a double H-shaped overall configuration comprising two H-shaped portions side by side and each forming two respective open channels with the channels on a first, cable connection side serving to receive the cable conductors, and on a second, jumper side serving to receive the jumper wires, the two channeis on each side being disposed in parallel with and at a spacing to one another; connecting contacts disposed in rows along the walls of the channels in the body, extending from the cable connecting side to the jumper side and carrying clamp elements for in particular non-stripping connection of the cable conductors and jumper wires respectively; an earthing frame provided in the heightwise region of the middle of the overall configuration, enclosing said overall configuration and extending through the spacing region; a receiving passage, for inserting and securing a non-stripped cable end, formed on the cable connecting side between the two H-shaped portions, the conductors of which cable end can issue at the cable end, be passed in bunches around the ends of the inner limb portion walls of the H-shaped configurations and be led back in the two channels on the cable connecting side in the opposite direction to the direction in which they extend in the secured cable end; and pockets disposed on the jumper side on both sides of the limb portions of the H-shaped portions, which pockets can receive holders for over-voltage arresters with the over-voltage arresters in contact with the earthing frame and the connecting contacts.

Such a terminal device can be convenient to handle, can ensure firm connection of the cable and, while being of simple structure, can provide satisfactory earthing of the connecting contacts by overvoltage arresters.

The receiving passage between the two H-shaped portions serves, overthe entire length ofthetermi- nal device, for receiving an entire end portion of the cable, thereby ensuring that the cable is satisfactorily fixedly arranged in and secured to the device.

Therefore, the cable to be connected firstly extends to an unstripped condition over the entire length of the terminal device. It is only at the opposite end of the insulating body that the cable conductors are divided into the two bunches which are led back into the channels associated therewith in the double H-shaped overall configuration, on the cable connecting side. Because the cable can be satisfactorily secured in place, the operations of contacting the conductors on both sides of the satisfactorily secured cable end portion can be conveniently and comfortably carried out. The double H-shaped configuration serves at the same time to form pockets on the jumper side of the device, where it is possible for the collecting holders of the over-voltage arresters, in the form of inserts, which arresters provide for satisfactory earthing of an entire insert, to be inserted.In fact, an earthing frame extends in the centre of the profile of the double H-shaped insulating body; at the same time, in the above-mentioned spacing region between the two parallel H-shaped portions, the earthing frame has a continuous web portion which gives strength and rigidity to the entire device and atthe same time accommodates the fixing means for holding the cable end portion which is in the receiving passage.

For those securing means, the insulating body may be provided on its jumper side with shaped recesses which are aligned with the receiving passage on the opposite cable connecting side. The securing means may be in the form of a compressed air valve which also perfc nSs monif;;in3 functions on the cable to be ccrnec±. y virtue of the continuous earthing frame in ire device, the earthing frame can be used a s mounting plate for mounting succ-s < - 3a portions of the elongate insulting body, which are arranged in a row, so that the insulating body does not need to be produced in a continuous portion over its entire length but, as required, can be composed of a given number of such portions of double H-shaped configuration.

The invention is diagrammatically illustrated by way of example in the accompanying drawings, in which: Figures 1 and 2 show a junction box with various terminal devices arranged in bays thereof, in crosssection and longitudinal section respectively on section lines I-I in Figure 2 and ll-il in Figure 1; Figure 3 shows a perspective view of a terminal device according to the invention, from a cable connecting side thereof, wherein, for reasons of greater clarity of the drawing, only a small number of cable conductors are shown and details of the device such as connecting contacts are not illustrated; Figures 4 and 5 show respectively a plan view onto the upper portion of the terminal device of Figure 3 and a view in longitudinal section therethrough taken on section line V-V in Figure 4;; Figure 6 shows a half-sectional end view of the device of Figures 3 to 5, showing the particular profile of the insulating body; and Figure 7 shows a perspective view of a collecting holder of over-voltage arresters used in the terminal device of Figures 3 to 6.

Referring to the drawings, a body 10 of a terminal device 11, which body is of plastics insulating material, is of an elongate rail-like configuration, could be made from individual sections, and has the overall configuration shown in Figures 3 and 6. The overall configuration of the body 10 comprises two H-shaped portions 12 which are integrally connected together and which extend parallel to each other and at a spacing 13 from each other. In the region of the middle of the body configuration, as considered in the direction of the depth thereof, the plastics body is enclosed by a metal earthing frame 14 which, as can be best seen from Figure 3, has longitudinal web portions 15 and a middlewebportion 16 which extends longitudinally in the above-mentioned spacing zone 13, all the web portions 15,16 being in the same plane.Disposed at the two end faces of the body 10 are transverse web portions 17 which connectthe longitudinally extending web portions 15 and 16 which in themselves could be of a cranked configuration in order to extend in alignment with a respective bar portion 18 of the H-shape of the two shaped portions 12. The outer longitudinal web portions 15 are provided with projecting fixing lugs 19 by means of which the whole terminal device 11 can be mounted on rails 21 within a bay 22 of a junction box 20 which is shown in Figures 1 and 2.Incoming and outgoing cables 23 are connected from one side, the cable connection side 24, to the respective terminal device 11, while jumper wires 26 extend away on the opposite side of the device, the jumper side 25, and provide for a connection between individual connec--d Gsnduclsrs 27 of two devices 11.

At can be bset s W=l from Figure 6, the profile of trie body 10, is fitted through the earthing frame 14 from the jumper side 25 so that one pair of limbs 28 of the H-shaped portions of the two shaped mem berms 12 pass through openings 29 in the frame 14 between the longitudinally extending web portions ,6 and 15 of the frame, to the opposite side which is the cable connection side 24. The other pair of limbs 30 of the H-shaped portions of the two shaped portions 12 remain projecting out beyond the plane of the earthing frame 14, on the jumper side 25.The limb portions 28 and 30 of the H-shapes close off the space within the H-shapes, whereby two channels 31 are formed on one side for receiving the jumper wires 26, as also shown in Figure 4, and two channels 32 are formed for the cable conductors 27 between the limb portions 28, opposite the channels 31.

The limb portions 28 and 30 each have respective chambers 33 extending therethrough in the direction in which the limb portions extend, the chambers 33 being provided towards the outside of the limb portions with openings 34 through which metal connection contacts 35 can be introduced into the interior of the chambers 33.

On the jumper side 25, web portions 36 extend parallel to the limb portions 30 on the outer sides thereof and at a spacing. As can be seen from the plan view of Figure 4, connecting web portions 37 extend between the limb portions 30 and the web portions 36 to divide the chambers 33 into pockets 38 into which inserts 40 forming over-voltage arresters, which will be described in greater detail with reference to Figure 7, can be inserted.The connection contacts 35 comprise metal strips having the folded configuration shown in Figure 6, and end portions of which from clamp elements 39 having a plurality of resilient tongue portions between which the conductors 27 and the jumper wires 26 respectively can be pressed into place by a simple insertion action, without removing the insulation When the ends of the above-mentioned wires are pressed into place, the insulation of the wires is cut through by the resilienttongue portions, thereby producing a satisfactory contact. At the same time, when inserting the wire in the above-indicated manner, because of a special tool which is used for that operation, the inserted contacted wire is cut to length.

A receiving passage 41 of an internal width sufficlient to receive the cross-section of the cable 23 is formed on the cable connection side 24 in the spacing region 13 between the two H-shaped portions 12, 12 of the body 10. A length 42 of the cable 23 is fitted into the passage 41, which length 42 as shown in Figure 3 is almost equal to the overall length of the body 10. The cable 23 is secured to the longitudinal web portion 16 of the earthing frame 14. This is effected primarily by the clip 43 shown in Figure 3 at the lower end of the terminal device. The method of fixing of the cable at the upper end thereof can be best seen from Figure 5, to which reference will now- be made.

The cable length 42 is engaged in the receiving passage 41, in an unstripped condition. It is only at its upper end thatthe above-mentioned conductors 27 are stripped and exposed; when that is done, a casing layer 45 comprising aluminium is also exposed and a portion thereof forming a tongue 46, is secured by way of a screw 47, to the longitudinally extending central web portion 16 of the earthing frame 14, for the purposes of making a contact. A connection housing 44 which can comprise plastics material is pushed over the cable 23 at the free end thereof. A shrink tube 48 is fitted at the transition between the cable 23 and the part of the housing 44 which is fitted thereover, the tube 48 contracting when subjected to the action of heat and providing a satisfactory seal between the cable 23 and the housing 44.The cable 23 used herein is of a particular kind for in its interior it includes a pipe 49 which forms part of a compressed air supply and which is connected within the housing 44 to a pipe 51 of a valve 50 which, by virtue of its screw fixing, also serves for mounting the housing 44 which carries the cable 23. After the cable conductors 27 have been taken out and the assembly secured together in the illustrated manner, the interior of the housing 44 is filled with casting resin 52. The valve 50 projects on the jumper side 25 of the terminal device and there is closed by a screwable cap 53.

The valve 50 and the components 51,49 and 52 connected thereto form part of a compressed air monitoring means. A pipe which is about 2 mm in diameter is sufficientforthe pipe 49, and terminates in a sleeve or socket (not shown) which is disposed in a connecting location between the cable 23 and a conventional other passage. In this way, pressure passes from the terminal device into the sleeve and the cable extending it, which can still have the paper insulation arrangements which were conventional previously and which can be monitored in respect of the ingress of moisture. The above-indicated fixing means 53,47 and 50 of the cable end 42 are disposed in a longitudinal central region 54 of the body 10, which is between the pockets 38 on both sides, as can be seen from the plan view of the jumper side 25 in Figure 4.Stiffening transverse walls 55 and a base wall 56 shown in Figure 5 are provided for that purpose in the above-mentioned longitudinal central region, between the web portions 36 forming the pockets. Atube portion 57 can also be provided in that region, for the valve 50 to extend through. The underside of the base wall 56 and the wall portions which form the pockets 38 are in contact with the upper side of the earthing frame 14. Angle portions 58 which are formed integrally on the body 10 can also engage the fixing lugs 19 on the earthing frame 14.

As can be seen from Figures 3 and 5, the cable conductors 27 issue atthe upper end of the passage 41 and are each passed around respective ends 59, Figure 5, of the inner limb portions 28 of the H-shaped configurations, the conductors being separated into two bunches 60, as shown in Figure 3.

The conductors then extend, in an opposite but parallel direction to the direction in which they extend within the cable end 42, within the channels 32 which are disposed on both sides of the passage 41, there to be connected to the clamp elements 39 of the connection contacts 35.

For this purpose, longitudinally extending guide bar portions 61 are arranged at the ends of the limb portions of the H-shaped portions, as can be best seen from Figures 4 and 6. For this purpose, the body 10 is produced in one piece in its particular configuration with all web portions, walls and base portions, and has pins or studs projecting atthe ends of the limb portions, while the guide bars 61 are produced separately and have complementary receiving means for receiving the pins or studs. The guide bars 61 are then secured by adhesive or welding to the free ends of the limb portions. The main purpose of the guide bars 61 is to close off the ends of the chambers 33 which extend through the limb portions 28 and 30 at both sides, while however leaving an opening for the clamp elements 39 at the ends of the connecting contacts 35.For this purpose, the guide bars 61 are provided with suitable apertures out of which the clamp elements 39 project but at the same time are held therein. The guide bars 61 also have edge bar portions 62 which project into the interior of the H-shaped configuration and which are provided with slot-like openings 63 which are respectively disposed in alignment with the associated connecting contacts 35. The slot configuration in this arrangement may be in the nature of a bayonet-connection-type slot which is open towards the interior of the H-shaped configuration. The required cable conductors 27 or a jumper wire 26 respectively are inserted through the opening and held in the desired aligned position relative to the contact 35.

The inserts 40 which can be inserted into the pockets 38 on the jumper side 25 are of the appearance which can be best seen from Figure 7. Each insert has a housing 64 of insulating material with a plurality of chambers 65 extending therethrough, the chambers having enlarged portions for receiving an over-voltage arrester 66. One outer flat side of the housing 64 is covered with a continuous earthing plate 67 which closes the chambers 65 on that side.

The opposite flat side which is the upper side as seen in Figure 7 remains open and respective contact springs 68 project out of the openings into the individual chambers 65 and are connected to the overvoltage arresters 66 which are disposed therebelow and which can be for example gas-filled. The housing 64 itself is provided with a lug 69 for handling thereof, which is simply moulded on the insulating material of the housing 64. Each insert 40 can be gripped by its lug 69 and engaged in the body 10 through the opening into the respective pocket 38 from the jumper side 25. When the insert 40 is fitted into the body 10, it assumes the position shown in Figure 6.

In the inserted condition, the plates 67 of the inserts 40 are on the side of pockets 38 which is towards the outer web portions 36, where they are disposed, at the bottom, L-shaped spring contacts 70, Figure 6, secured to the earthing frame 14. A single respective spring contact 70 in each pocket 38 is suf ficientto form a contact of the entire group of overvoltage arresters 66 in one of the inserts 40, with the earthingframe 14.

On the opposite flat side of the inserted inserts 40, the contact springs 68 which project cut of each chamber 65 of the inserts project in through the opening 34 of the chambers 33 carrying the connecting contacts 35, such that the contact springs 68 make contact with the contacts 35. For this purpose, the connecting contacts 35 are provided with a cranked offset portion 71 which is directed towards the chamber opening 34 and which is important for satisfactory contacting of the contact springs 68 of the inserts 40. After the inserts 40 are fitted into position, only the handle portions 69 project out of the pockets 38 on the jumper side. This can be seen from Figures 5 and 6.

In use, a fully assembled terminal device 11 has a length 42 of the cable 23 engaged in and secured in the passage 41. The two bunches 60 of cable conductors 27 are then taken outatthe upper end and passed back into the respective channels 32 on both sides of the cable, where they are brought into contact at the guide bars 61 therein, with the clamp elements 39. Corresponding contact is now also made on the jumper side, where the jumper wires are introduced into the interior of the channels 31 of the shaped portions on that side, and connected in a corresponding manner to the clamp elements of the connecting contacts 35 which project out at that point. After the connection is fully made, the connecting locations on the opposite sides can be covered by a front protective cap 72 and by a rear protective cap 73, in the region of the leads.Preferably caps 72 and 73 are used which correspond to the length of a pocket 38.

The rear protective cap 73 has extended side walls 74 which, on the cable connection side 24, cover over the limb portions of the H-shaped portions on that side, with the outwardly projecting clamp elements 39. The side walls are turned outwardly at their free edges to form a flange and can be secured to the earthing plate 14 by screw fixing means.

The front protective cap 72 is of a depth 75 which is greater than the height of projection of the elements which project out of the limb portions on the jumper side 25, in other words, it extends overthe outwardly projecting handling lugs 69 and the clamp elements 39. The front protective cap 72 can be fitted in place by snap fastening means, for which purpose it carries resilient tongue portions 76 with projections 77 at their ends, which are best also integrally moulded on the cap in the production thereof. The tongue portions 76 engage into the longitudinal central region 54 on the body 10 so that their projections 77 co-operate with corresponding projections 78 which are formed on the transverse walls 55 provided on the body 10. The projections 77 and 78 come into engagement with each other, thereby securing the cap 72 to the body 10.

Claims (10)

1. Aterminal device for low tension cables, in particular telecommunication cables, for connecting the conductors of a cable to jumper wires which can be connected to conductors of a further cable, comprising a body of insulating material having a double H-shaped overall configuration comprising two H-shaped portions side by side and each forming two respective open channels with the channels on a first cable connection side serving to receive the cable conductors, ç q on a second, jumper side serv ing to receive the jumper wires, the two channels on each side being disposed in parallel with and at a spacing to one another; connecting contacts disposed in rows along the walls of the channels in the body, extending from the cable connecting side to the jumper side and carrying clamp elements for in particular non-stripping connection of the cable conductors and jumper wires respectively; an earthing frame provided in the heightwise region ofthe middle of the overall configuration, enclosing said overall configuration and extending through the spacing region; a receiving passage, for inserting and securing a non-stripped cable end, formed on the cable connecting side between the two H-shaped portions, the conductors of which cable end can issue at the cable end, be passed in bunches around the ends of inner limb portion walls of the H-shaped configurations and be led back in the two channels on the cable connecting side in the opposite direction to the direction in which they extend in the secured cable end; and pockets disposed on the jumper side on both sides of the limb portions of the H-shaped portions, which pockets can receive holders for over-voltage arresters with the over-voltage arresters in contact with the earthing frame and the connecting contacts.

2. Aterminal device according to claim 1, in which, on its jumper side, the insulating body has recesses for disposing securing means for the cable, the recesses being in alignment with the receiving passage on the opposite cable connecting side.

3. Aterminal device according to claim 2, in which the fixing means comprises a compressed air valve to which a monitoring pipe of the cable is connected.

4. Aterminal device according to claim 3, in which the elongate insulating material body comprises a group of sections of double H-shaped configuration, which are disposed in succession in a row and which are secured on the common earthing frame.

5. Aterminal device according to claim 4, in which the ends of the limb portions of the H-shaped configuration carry longitudinally extending guide bars which are provided with recesses for holding the outwardly projecting ends of the connecting contacts and edge bar portions of the guide bars which project inwardly of the H-shaped configuration each have openings extending respectively in alignment with the connecting contacts for insertion into the openings of the associated cable conductors and jumper wires respectively.

6. A terminal device according to claim 5, in which the openings are each in the form of a bayonet-connection-type slot.

7. Aterminal device according to any one of claims 1 to 6, in which the limb portions of the H-shaped configuration are provided with chambers which extend in the direction in which the limb portions extend and which are each open to the outside of the limb portions and serve for insertion of the connecting contacts.

8. Aterminal device according to any one of claims 1 to 7, in which each of the holders comprises an insert housing with chambers for the individual over-voltage arresters and a side which is towards the limb portions of the H-shaped configurations is provided with a group of projecting contact springs which are each connected to a respective one of the over-voltage arresters.

9. Aterminai device according to claim 8, in which the side of the insert housing which is remote from the channel of the respective H-shaped configurations is provided with an earthing plate which connects all over-voltage arresters of the respective holder and against which a contact which is disposed in the pocket and connected to the earthing frame comes into contact, in the inserted condition ofthe holder.

10. A terminal device for low tension cables substantially as herein before described and illustrated with reference to the accompanying drawings.