GB2187049A

GB2187049A - Insulation displacement connector for joining flat cables

Info

Publication number: GB2187049A
Application number: GB8604399A
Authority: GB
Inventors: Richard William Sheppard; Michael Joseph Breen
Original assignee: Allied Corp
Current assignee: Allied Corp
Priority date: 1986-02-21
Filing date: 1986-02-21
Publication date: 1987-08-26
Also published as: GB8604399D0; EP0233536A1

Description

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GB 2 187 049 A

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SPECIFICATION

Electrical connection device for use with flat cable

5 The invention relates to connection devices for use with flat power distribution cables ofthetype designsforundercarpetuse.

One such cable is described in British patent application No. 8523359 of 20th September 1985 and 10 consists of a wideflat earth strip under which are arranged, side-by-side, narrower live and neutral conductors. The live and neutral conductors are provided with an electrically-insulating sleeve and the cable as a whole is also provided with suitable 15 insulation intheform of a flat insulative envelope sealed only along its side edges. The earth strip serves both as the earth conductor and as an electromagnetic screen forthe live and neutral conductors. It is only lightly bonded to the live and 20 neutral conductor package so that it can easily be separated from them.

One connection device for use with a cable of this kind is described in British patent application No. 8424281 dated 26th September 1984. The device has 25 a base over which the cable can be laid, an upper member which is positioned overthe cable and secured to the base and an insulative separating plate for location between the upper and base members, which, in use is passed between the earth 30 conductor and live and neutral conductors respectively, of the cable. The base and upper members are provided with insulation displacing contacts (IDC) by means of which connections to the cable conductors are made the separating plate 35 preventing the IDC means passing rightthrough eitherthe live or neutral conductors into the earth strip. The arrangement described in British patent application No. 8424281 is primarily intended for mounting a socket or junction box of conventional 40 type.

The invention is defined in the claims appended hereto, to which reference should now be made.

Two connection devices in accordance with the invention will now be described in detail, by way of 45 example, with reference to the drawings, in which:

Figure 1 is a perspective view of a first connection device for flat cables in accordance with the invention;

Figure .2 shows the base member of the device of 50 Figure 1;

Figure 3 is a plan view of the base member of the device of Figure 1 with the cables laid over it;

Figure 4 is a schematic sectional view of the device ofFigurel;

55 Figure5\san exploded view of a second connection device in accordance with the invention;

Figure6\sa plan viewanalogousto Figure3ofthe device of Figure 5; and

Figure 7 is a schematic sectional view of the 60 connection device of Figure 5.

The connection device of Figures 1 to 4 is intended to serveadual purpose; it connects two cable runs extending perpendicularly to one another and mounts a coventionai socket or junction box. 65 The connection device comprises a base member

10, an upper member 12 and a separating plate 14. The base member 10 is generally rectangular and is provided with two broad shallow grooves 16 extending perpendicularly to one another across its 70 upper surface for receiving two perpendicular lengths of flat cable 18 (only one of which is shown in Figure 2). The periphery of the base member 10 may be slotted to receive the ends of stainless steel strips which are often placed overflat cables of the kind 75 described to protectthem from mechanical damage.

Mounted in shallow recesses 20formed in the base member 10 are insulation-displacing contact ("IDC") means 22. Each IDC means 22 is generally triangular in shape having the form of right-angled 80 isosceles triangle, and is provided at two of its vertices with rings of upwardly extending pointed teeth or tines 24. At its third vertex the IDC means 22 has a screwterminal post 26 of a conventional kind. The IDC means 22 are positioned diagonally 85 opposite each other on the base member 10 so that when the cables 18 are laid over them one ring of teeth 24 of each IDC member lies beneath the central region in which the cable runs intersect each other and the other ring of teeth 24 lies within one of the 90 cable-receiving grooves 16 but outside the central intersection area. The positions of the IDC means 22 are shown most clearly in Figure 3 of the drawings. Each terminal post 26 locates in a notch 25formed at one of the intersections of the cable-receiving 95 grooves 16.

The upper member 12 of the connection device is in the nature of a box-like cover which can be secured overthe base member 10 and cables 18 by means of, for example, clamping screws (not 100 shown). The upper member 12 may incorporate or may include meansfor mounting a junction box or power outlet socket 30 and may be provided with apertures 32 to house telephone or data outlet sockets which are themselves connected to 105 undercarpet networks.

In use, as shown in Figure 4, the live and neutral conductors 34 and 36 of one cable 18 are moved away from the earth conductor 38 so that the other cable 18 may be inserted between them. Before 110 doing so, however, an insulative separating plate 14 is inserted between the live and neutral 34 and 36 conductors and earth conductor 38, respectively, of the second cable 18 in the region which, in the assembled junction, will lie in the central 115 intersection region of the base member 10. The second cable 18 is then inserted through thef irst until the separating plate 14 lies in the intersection of the two cables 18. Both cables 18 are positioned so thatthe live and neutral conductors 34 and 36 lie 120 beneath the separating plate 14toensurethatthe polarities are correct, with the earth conductors 38 adjacent one another above the separating plate 14.

The cable junction is then positioned on the base member 10 so thatthe cables 18 lie in the 125 cable-receiving grooves 16. The upper member 12 is located overthe base member 10 and cable junction and then clamped down onto the base member 10. As the upper and base members 10 and 12 are forced together the teeth 24 of the IDC means 22 pierce the 130 insulation surrounding the live and neutral

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conductors 34 and 36 of the two cables 18 to contact the conductors and connect each to the corresponding conductor of the other cable 18. The IDC means 22 are prevented from passing through 5 the live and neutral conductors 34 and 36 and contacting the earth conductors 38 by the intervention of the insulative separating plate 14 which is of dimensions such that it overlies both rings of teeth 24 of each IDC means 22 but can be 10 located in the cable-receiving grooves 16.

The underside of the upper member 12 may be provided with suitable IDC means (not shown) by means of which the earth conductors 38 of the two cables 18 are connected together. Again, the 15 presence of the separating plate 14 will preventthe IDC means passing through the earth conductors to contactthe live or neutral conductors.

It will be appreciated that a connecting device of the kind shown in Figures 1 to 4 can be used to 20 connect two perpendicularly-extending runs of flat undercarpet cable at right-angle bends and T-junciions as well as at cross-overs, simply by cutting the cable off short at the connection device as desired. It may also be used to connect two parallel 25 lengths of cable whose ends are butted together provided the join line passes between the two IDC portions of each IDC means.

Where two runs of cable are to be connected, but it is not required to mount an outlet at the junction, the 30 connection device shown in Figures 5 to 7 can be used.

The device, again, comprises a base member 110 provided with perpendicular cable-receiving grooves 116 and IDC means 122 over which the 35 cables 118 are iaid. The IDC means 122 are each formed of sheet metal cut and shaped to form two rings of four upwardly-projecting tines 124. Each of the IDC means 122 is located in a recess 120 formed in the base member 110 and they are similarly 40 positioned to the IDC means in the device of Figures 1 to 4. No terminal posts are, however, provided as no connections to sockets or junction boxes are to be made.

The base member 110 is generally square and 45 midway along each of its edges it is provided with a raised rectangular platform 140 having formed in it four shallow curved-cross-section depressions or recesses 142. The function of the recesses 142 will be made apparent below. The corners of the base 50 member 110 may also be provided with slots 144for receiving the ends of the stainless-steel strips 146 which are commonly used to protect undercarpet cables from mechanical damage.

The upper member 112 is in the form of a shallow 55 cover plate which locates overthe base member 110 and the cable-junction and which may be secured to the base member by means of, for example, clamping screws (not shown). On the underside of the upper member 112 is formed a cross-shaped 60 boss 150whichisofdimensionssuchthatitwill locate in the cable-receiving grooves 116 when the upperand base members 110and 112are secured together. The end surface of the boss 150 is provided with depressions or recesses 152 similar to the 65 recesses 142 formed on the base member 110. When the base and upper members are secured together the tines 124 of the IDC means 122 of the base member 110 are received in the recesses 152 in the upper member 112.

70 Between the base and upper members 110 and 112 is positioned an earth ring 160intheform of a conductive plate which is shaped to fit the end surface of the boss 150 on the underside of the upper member 112. The plate is cut away to form a central 75 opening 166 to expose the recesses 152 and is provided with four sets of downwardly-projecting tines 164 which, when the connection device is assembled, are received in the recesses 142 of the base member 110. For convenience, the earth ring 80 160 is fixed to the underside of the boss 150 on the upper member.

In use, each cable 118 in turn is laid overthe base member 110 as shown in Figure 6 and stripped of its earth conductor 138 in the region in which the cables 85 118 intersect. The upper member 112, bearing the earth ring 160 is then secured to the base member 110, clamping the cables 118 between the two. As the base and upper members 110and112are brought together, thetines 124 of the IDC means 122 onthe 90 base member 110 pierce the cable insulation to contactthe live and neutral conductors 134 and 136 of the two cables 118 and connect them together. The tines 124 and recesses 152 on the underside of the upper member 112 cooperate to cause the 95 coppersheet of which the live and neutral conductors 134 and 136 are formed to deform around the tines 124 ratherthan being ruptured by them. The deformation of the conductors 134 and 136 around the tines 124 leads to better electrical 100 contact with the IDC means 122. Because the earth conductor 138 has been cutaway to expose the recesses 152, there is no possibility of inadvertently connecting the live or neutral conductor 134 or 136 to the earth conductor 138 by means of the IDCtines 105 124.

Atthesametime,thetines 164oftheearth ring 160 pierce the cable insulation to contactthe earth conductors 138 of the two cables 118 to connect them together. Thetines 164and recesses 142 110 formed in the base member 110 cooperate in a similar mannerto that described above to ensure thatthe earth conductors 138 are deformed around thetines 164, ratherthan pierced by them, to ensure good electrical contact. Because the tines 164 and 115 recesses 142 are positioned centrally ofthe cables 118 they engage the portion of each earth conductor 138 which overlies the insulated gap between the live and neutral conductors 134 and 136. Thetines 142 are also positioned outside the area overwhich 120 the cables 118 intersect. There is, therefore, no risk of inadvertently connecting live, neutral and earth conductors by means ofthe earth ring tines 164.

The connection device may again be used to form cross-overs, T-junctions and right-angle bends. It 125 may also be used to connect together two separate lengths of cable whose ends are butted together. In this latter case, however, care must again be taken to ensure that the join line between the ends of the two cables passes between the two rings of tines 142 on 130 each ofthe two IDC means 122.

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It will be appreciated thatthe connection device shown in Figures 5 to 7 is easy to use, correct connection being effected once the earth conductors have been removed simply by clamping the cables 5 between the base and upper members ofthe device. The use ofthe IDC means is in part responsiblefor the simplicity ofthe device and,furthermore,

enables itto be made extremely slim in profile; the assembled junction may be as little as 5 mm in

10 thickness. The cooperation of the IDC tines with the recesses also ensures that a good electrical contact is made.

Claims

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1. Aconnectiondeviceforconnectingflatcables at an angle to one another comprising a base member having a cable-receiving surface overwhich the cables to be joined are to be laid, an upper

20 memberfor location overthe cable-receiving surface ofthe base member, securing meansforsecuring the upper and base members together and insulation displacement contact (IDC) meansinthe base memberfor connecting corresponding

25 conductors ofthe cables to one another.

2. Aconnection deviceforflatcablescomprising a base member having a cable-receiving surface overwhich a cable is to be laid, an upper memberfor location overthe cable-receiving surface ofthe base

30 member and securing meansforsecuringtheupper and base members together, one ofthe upperand base members being provided with IDC means including a projecting tine for contacting a conductor ofthe cable and the other having a recess for

35 receiving the tine; the recess co-operating with the tine, in use, to cause the cable conductorto deform aroundthetine.

3. A device according to claim 2 for connecting flat cables to one another in which the IDC means are

40 disposed in the base member and arrangedto connect corresponding conductors ofthe cables to one another.

4. A device according to claim 2 or 3 in which each IDC means is provided with two IDC portions

45 electrically connected together; one IDC portion lying within an area of the cable-receiving surface overwhich both cables to be connected pass for contacting a conductor of the cable closest to the base member and the other IDC portion lying within

50 the cable-receiving surface but outside the said area forcontacting aconductorortheothersaidcable.

5. A device according to claim 4 having two IDC means located adjacent diagonally opposite corners of the said area.

55 6. Adevice according to and preceding claim in which the IDC means are provided with at least one screw terminal for connection to a conductor wire.

7. A device according to any preceding claim in which each IDC means is provided with a numberof

60 projecting tines for piercing the cable insulation to contactthe cable conductor.

8. A device accoding to claim 7 when appendant to claim 1 including an insulative separation plate for location between the base and upper members and

65 which in use is passed transversely through a cable to separate conductors thereof.

9. Adevice according to claim 7 having a plurality of recesses formed in the surface of the upper memberfacing the base member, for receiving the

70 tines the recesses cooperating, in use, with the tines to cause the cable conductors to deform aboutthe tines.

10. A device according to any preceding claim comprising further IDC meansfor contacting

75 conductors on the other side ofthe cables.

11. A device according to claim 10 which the further IDC means is in the form of a conductive plate mounted, in use, between the upper member and the cables and having a plurality of projecting tines

80 thereon for contacting the earth conductors ofthe cables to connect them together.

12. A device according to claim 11 inwhichthe base member is provided with a plurality of recesses formed in its surface facing the upper memberfor

85 receiving the tines ofthefurther IDC means, the recesses cooperating, in use, with the tines to cause the earth conductors to deform aboutthetines.

13. A device according to claim 10,11 or12in which thefurther IDC means are arranged so asto

90 contactthe cable conductors in a region overlying insulating material isolating conductors at the side of the cable adjacent the base plate.

14. A device according to claim 11 or12inwhich the conductive plate is formed with one or more

95 openings for exposing the recesses formed on the upper member.

15. Aconnection deviceforflat cables substantially as hereinbefore described with reference to Figures 1-4 ofthe drawings.

100 16. Aconnectiondeviceforflatcables substantially as hereinbefore described with reference to Figures 5-7 ofthe drawings.

Printed for Her Majesty's Stationery Office by Croydon Printing Company (UK) Ltd,7/87, D8991685.

Published by The Patent Office, 25 Southampton Buildings, London, WC2A1 AY, from which copies may be obtained.