GB2140607A - Electrical cord for modular connectors - Google Patents

Abstract

An electrical cord for use with a modular connector, such as a modular plug. The cord is formed of a core of electroconductive wires, such as copper wires 5, which is surrounded by a springy electroconductive foil 3b and an insulating layer 3c. Synthetic fibers may be used with the copper wires to increase the tensile strength of the cord. The cord has a much higher conductivity than conventional telephone cord. <IMAGE>

Description

SPECIFICATION Electrical Cord for Modulator Connectors This invention relates to an electrical cord for modular connectors.

In connecting the transmitter and receiver of a telephone instrument by a connecting wire or cord, use has been made of a so-called modular connector for the jack and plug. These connectors have had wide acceptance, as they are relatively small and inexpensive. Use of thins type of connector has been gradually spreading to connections between other electronic equipment.

Heretofore, there has been used as the connecting wire fortelephone sets a cord which includes a very flexible core. Typically, the core ofthe cord comprises an aggregate of synthetic fibers which have a high tensile strength, are highly flexible and are highly insulating such as nylon fiber. Surrounding each core, an electroconductivefoil having a springy property, such as a phosphor bronze foil, has been wound. Each wire is then provided with an insulating exterior cover, such as a plastic material, and the wires are grouped together and provided with an insulating exterior cover, again such as a plastic material. When this wire is inserted into a modular plug, insulation displace ment contacts are used to tap into the electroconductive foil, which then retains the contacts by its springy force.

However, in such wire the phosphor bronze foil, which is the electroconductive part, has very appreciable electrical resistance. Furthermore, if the thickness of the foil is large, tapping in ofthe contacts is very difficult; consequently, the foil has to be relatively thin. Thus,thethickness ofthe foil is determined by the difficulty of tapping in the contacts, regardless of the electric currentwhich passes through the foil.

Accordingly, the resistance of this conductor is undesirably high, such as ofthe order of about 1.5 ohms per meter.

As a result, use ofthistype of cord has been limited to areas in which the voltage drop is not a problem, such as the length of a typical telephone cord for the current flowing through the mentioned type of connector was developed. Hence, use of this cord has been restricted where the current is large although the length is aboutthe same as a telephone cord, orwhere the length between the equipment is long although the current is aboutthe same or even less.

It is an object ofthe invention to provide a cord for usewith modular connectors which can be used in long lengths orwith larger current.

In accordance with this invention, there is provided in an electrical cord for use with a modularconnector, the cord comprising atleastonewireelement comprising a core, a springy electroconductive foil surrounding the core and an insulating cover surrounding the foil, the improvement comprising that the core includes electroconductive filaments.

Preferably, these filaments are copper wires, which may be mixed with syntheticfibers providing higher tensile strength, such as nylon fibers.

The foil preferably is formed of phosphor bronze alloy. Further in accordance with this invention, there is provided an electrical assembly comprising a modular connector in electrical communication with an electrical cord, the cord comprising at least one wire element comprising a core, a springy electroconductivefoil surrounding the core, and an insulating cover surrounding the foil,the core including eiectroconductive wires which are in electrical connection with the modular connector.

Preferably, the modular connector comprises a modular plug which includes insulation displacement contacts that make electrical connection through the foil with the electroconductive wires ofthe core.

By the use of electroconductive filaments in the core ofthe cord, the conductor resistance is drastically reduced in comparison with conventional cord of the same outer diameter wire. As a result, the cord ofthis invention can be used in relatively long lengths and with large currents. The core can be used to connect electronic equipment other than telephones.

In orderthatthe invention maybe more clearly understood and readily carried into effect it will be further described by way of example with referenceto the accompanying drawings of which: Figs. 1 through 1(d) are views of a conventional modular plug connector, showing the upperside,the lower side, a cross-section before connection of a cord and a cross-section showing connection ofthe cord, respectively, Figs. 2(a) through 2(c) are views of a conventional modular jack socket illustrated isometrically, in crosssection, and in cross-section with plug inserted, respectively, Fig. 3 is an isometricviewofa conventional cord used in a modular connector, Fig. 4 is an isometric view of one section ofthe cord ofthis invention, and Fig. 5 is a partial cross-section view illustrating the connected state of the contact to the cord.

With reference to Figs. 1 a, 1 b, 1 c and 1 d, a conventional modular plug 1 includes an insulating body 1 a, a cord insertion opening 1 b, a wire insertion opening leandacord retaining member it mounted in hole 1 e. A plurality of insulation displacing contact members 1fare received within tap-in holes lh which are defined by separator walls 1 g. Each contact piece if has contact protrusions 1f'. When the contact pieces if are installed in their respective holes 1 h, contact protrusions 1f' are tapped into the phosphor bronze foil 3b of each wire 3d through the insulating exterior cover 3c, as is described below with reference to Figs.

3-5.

In Figs. 2a, 2b and 2c, the conventional modularjack socket 2 is formed of an insulating body 2b. A plurality of springy wire contacts 2a are mounted within body 2 such that they open into plug insertion hole 2c. Plug insertion hole 2c is adapted to receive plug 1 in an electrical connecting manner, such that each ofthe wire contacts 2a is brought into contact with the end face of a contact piece if. In this manner, jack 2 performs the connection between fixed equipment.

Fig. 3 depicts a conventional cord 3 which is used for rnodulartelephone connectors. Cord 3 is formed of a plurality of cores 3a, each ofwhich comprises an aggregate of flexible synthetic fibers, such as nylon fibres. These fibres are veryflexible, have a high tensile strength and are highly insulating. Over each core 3a is wrapped an electroconductive foil 3b, such as phosphor bronze, which has a springy property.

Overthefoil 3b is applied an insulating exterior cover 3c, which may be a plastic material, such as polyester, that is applied via extrusion. Each resultantwire3d is aligned with other wires and provided with an insulating exterior cover 3e, which likewise may be formed of a plastic material.

In accordance with this invention, as shown in Fig. 4 the cord is provided with a core formed of an aggregate of electroconductive filaments 5. These filaments are preferably formed of twisted copper wires. As a result, the core has good electroconductivityand hasa diameterwhich givesthe necessary flexibility. Around each core is wound anelectrocon- ductivefoil 3b of phosphor bronze alloys as in the conventional product. Foil 3b is in turn provided with an insulating cover 3c, as in the conventional wire, to form individual wires 3d. A plurality of wires 3d is provided with an insulating exterior cover 3e as in the conventional cord, such that the wires are arranged pamllelly.

When the cord is inserted into plug 1, the contact pieces 1f pierce through exterior cover 3c and are tapped into foil 3b as shown in Fig. 5, with bent portions 3b' of foil 3b contacting the contact protrusions 1f' to connectthe cord to the plug. By the use of wires 5 in the core which have good electroconductivitywhen the contact pieces if are tapped into the phosphor bronze foil 3b, the electrical current flows into the phosphor bronze foil 3b,the electrical current flows into the wire through the contact piece if.This current is divided into the phosphor bronze foil 3b and the aggregate Softhecopperwires bytheir resistances, and most ofthe currentflows through core 5 of copperwirewhich has a low resistance. Consequently,the conductor resistance ofthe cord can be drastically reduced in comparison to the convention cord even when the outer diameter ofthe element wire is equal, and this reduces the limitations on the cord length to be used and the value ofthe current flow. Thus, the use of modular connectors is greatly extended to other electronic devices and can be used overgreater distances.

Since in general metallicwiressuch ascopperwire are inferiorto syntheticfibes such as nylon in terms of tensile strength, in orderto increasethetensile strength ofthe cord, nylon or other synthetic wires may be included in the core 5 of copperwires yet in such a mannerthatthe passing of electric current is not impeded. Also, it should be noted that the number ofelementwires in the cord can be any desired number.

The present invention thus provides an electrical cord for use with modularconnectorswhich has low conductor resistance and thus can be used in many applications.

Claims (19)

1. In an electrical cord adapted for use with a modularconnector, said cord including at least one wire element comprising flexible a core, a springy electro-conductive foil surrounding said core and an insulating cover surrounding said foil, wherein said core includes electroconductive filaments.

2. The electrical cord of claim 1 wherein said core comprises a mixture of said electroconductivefilaments and insulating synthetic fibers providing higher tensile strength.

3. The electrical cord of claim Swherein said syntheticfibersare nylon fibers.

4. The electrical cordofclaim 1 or2whereinsaid electroconductive filaments are copperwires.

5. The electrical cord of claim 3whereinsaidfoil is formed of a phosphor bronze alloy.

6. The electrical cord of claim 5 including a plurality of said wire elements, and an exterior insulating cover surrounding said insulating cover of each of said wire elements.

7. The electrical cord of any of claims 1 to 6 wherein said modularconnector is a modularplug.

8. The electrical cord of claim 7 wherein said modular plug comprises a pluralityof insulation displacing contacts, said contacts being adapted to pierce through said insulating cover of each wire element and said foil of each wire elementto make electrical contactwith said copper wires in each of said cores.

9. An electrical assemblycomprising a modular connector in electrical communication with an electrical cord, said cord comprising at leastonewire element comprising a flexible core, a springy electroconductive foil surrounding said core, and an insulating cover surrounding said foil, said core incuding electro-conductivefilaments which are in electrical communication with said modular connector.

10. The electrical assembly of claim 9wherein said modular connectorcomprisesamodular plug.

11. The electrical assembly of claim 10wherein said modular plug has at least one electrical contact, said electrical contact extending through said cover and said foil and being in communication with said electroconductive wires of said core.

12. The electrical assembly of claim ii wherein said core includes a plurality of copperwires and said foil isformed of a phosphor bronze alloy.

13. The electrical assemblyofclaim 12wherein said core comprises a mixture of copperwires and synthetic fibres.

14. The electrical assembly of claim 13 wherein said synthetic fibers are nylon fibers.

15. The electrical assembly of any of claims 9 - 14 said cord comprises a plurality of said wire elements, and includes an exterior insulating cover surrounding said wire elements.

16. The electrical assembly of claim 16wherein said plug comprises a plurality of electrical contacts.

17. The electrical assembly of claim 17 wherein said contacts are insulating displacement contacts.

18. An electrical cord substantially as described herein with reference to Fig. 4 ofthe accompanying drawings.

19. An electrical assembly substantially as described herein with reference to Figs. 1 to 5 of the accompanying drawings.