Electrical Conductor Assembly

This invention relates in general to electrical conductor assemblies and deals more particularly with an improved flexible electrical supply cable.

Recent deregulation of the telephone industry has created further opportunity for others to enter the residential and light commercial telephone cable installation market. It is anticipated that telephone companies may be abandoning responsibility for installation and maintenance of telephones as a result of government "unbundling" of pricing for telephone installation and service, since the cost of new construction installation is likely to become prohibitive due to the loss of supporting business revenues derived from service. It is expected that this gap will be filled by the electrical contractor.

Now with the expanding availability of cable television and data service (CATV/DATA) throughout the United States, an additional cable installation, made at a proper time in a new home construction, is highly desirable and, if available, would probably be specified in a large percentage of new housing starts. A properly trained electrician, equipped with adequate tools, should be capable of installing telephone and CATV/DATA service as well as conventional power supply service.

Heretofore outlet boxes have been available which facilitate single point outlets for power and other service, such as telephone service, for example, however, such systems generally utilize separate cables for each service.

Established electrical codes generally prohibit the presence of electrical supply conductors and electrical conductors for providing other unrelated service, such as a telephone service, within a common insulation jacket, because of potential electrical shock hazards. If a nail or staple is inadvertently driven through such a common jacket and into contact with a normally energized electrical supply conductor and one of the conductors associated with another service, such as, for example, telephone service, the telephone service conductor may acquire the higher voltage potential of the power supply source. The resulting condition presents a potentially serious electrical shock hazard to the telephone installer or user.

It is the general aim of the present invention to provide an improved flexible free-stripping electrical cable assembly which includes within the common jacket power supply conductors and electrical conductors associated with other unrelated service and which overcomes or at least substantially minimizes problems normally associated with such cable arrangement.

A more specific aim of the invention is to provide an improved electrical conductor assembly or cable which enables simultaneous installation of electrical conductors for supplying a plurality of unrelated services and which may be coiled and stored on a reel without kinking the individual conductors which comprise the cable and readily adapted to conform to specific conditions encountered during cable installation.

In accordance with the invention an electrical cable comprises a plurality of groups of axially elongated flexible electrical conductors including first, second and third groups, each group including at least one electrical conductor. The groups of conductors are contained within a unitary flexible axially elongated jacket of dielectric material which separates and insulates the conductors of each of the groups from the conductors of the other of the groups. The jacket has distinct axially elongated tubular portions which include a first tubular portion containing the conductors of the first group, a second tubular portion containing the conductors of the second group and a third tubular portion containing the conductors of the third group. A plurality of integral axially elongated web portions hingedly connect the tubular portions for movement relative to each other between first and second positions and include first and second web portions integrally connected to the first tubular portion at points of connection angularly spaced generally about the central axis of the first tubular portion. The first web hingedly connects the second tubular portion to the first tubular portion. The second web hingedly connects the third tubular portion to the first tubular portion. The conductors of the first, second and third groups are disposed to one side of a plane which passes through the points of connection and the conductors of the second group are disposed to the opposite sides of the plane when the tubular portions are in the first position. The conductors of each of the groups are disposed to the same side of the plane and in generally side-by-side relation to each other when the tubular portions are in the second portion.

FIG. 1 is a fragmentary plan view of an electrical cable embodying the present invention.

FIG. 2 is a sectional view taken along the line 2--2 of FIG. 1.

FIG. 3 is similar to FIG. 2 but shows the components which comprise the cable in another position.

FIG. 4 is similar to FIG. 2 but shows another electrical cable embodying the present invention.

Turning now to the drawing, an axially elongated, flexible electrical conductor assembly embodying the present invention and indicated generally by the reference numeral 10 comprises a composite cable which includes components for providing power, CATV/DATA and telephone service. The illustrated cable 10 is of a free-stripping type, particularly adapted to facilitate simultaneous installation of electrical conductors essential to the provision of such service and includes three components which comprise groups of electrical conductors designated generally by the numeral 12, 14 and 16. A unitary dielectric insulating jacket, indicated generally at 17, separates and insulates the electrical conductors which comprise each of the groups of conductors from the conductors of the other of the groups of conductors.

The insulation jacket 17 is preferably made from an elastomeric material, has three distinct free-stripping tubular portions each having a generally circular cross section. A first portion of the jacket, indicated by the numeral 18, generally coaxially surrounds the electrical conductors which comprise the first groups of conductors 12. These conductors are particularly adapted to supply telephone service. A second portion of the jacket, indicated by the numeral 20, generally coaxially surrounds the conductors of the second group 14, which constitute power supply conductors. A third portion of the jacket, indicated at 22, coaxially surrounds the third group 16, which comprises a coaxial cable arrangement for CATV/DATA service.

The jacket second portion 20 is connected to the first portion 18 along its length by an integral longitudinally extending web 24. A similar web 26 connects the first portion 18 and the third portion 22. Referring particularly to FIG. 2, it should be noted that the webs 24 and 26 are connected to the jacket first portion 18 at points of connection 27 and 29 angularly spaced about the central axis of the first tubular jacket portion 18 and located to one side of an axial plane 28 which contains the axis of the first portion 18. The webs 24 and 26 provide flexible hinge connections as well as regions of weakening between the component parts of the cable 10, for purposes which will be hereinafter further evident.

Considering the various components of the cable 10 in further detail, the conductor group 12, which is particularly adapted to provide telephone service, preferably includes four non-twisted, individually insulated and color coded AWG No. 24 solid wire telecommunications conductors 32, 32.

The power supply component which comprises the conductor group 14 is particularly adapted for residential power supply and includes two insulated and color code AWG No. 14 solid wire conductors 34, 34 and an uninsulated or bare metallic ground conductor 36 contained within a generally cylindrical dielectric sheath defined by the jacket portion 20. The insulated conductors 34, 34 and the bare metallic conductor 36 are surrounded by a spiral wrapping of metallic foil 38. The metallic foil, which is preferably copper, comprises a flexible coaxial sleeve surrounding the conductors of the group 14, is contained within the dielectric insulation sheath 20 and is in immediate or interrupted electrical contacting engagement with the bare metallic conductor 36 along a substantial portion of its length for a purpose which will be hereinafter further evident.

The CATV/DATA component 16 conforms with present industry standards and includes a single AWG No. 20 solid wire conductor 40 coaxially surrounded by a generally cylindrical layer of foam dielectric material 42. A generally cylindrical flexible shield 44, preferably formed by a spiral wrapping of aluminum foil, coaxially surrounds the dielectric layer 42. Another flexible cylindrical shield 46, preferably made from sixty percent aluminum braided wire, coaxially surrounds the shield 44 within the insulation sheath formed by the generally cylindrical jacket portion 22.

The web portions 24 and 26 extend along the length of the cable 10 in generally parallel relation to the longitudinal axis of the cable and form flexible hinges between the components 12, 14 and 16 so that the three components may be positioned with the conductors thereof in generally side-by-side or in line relation, as shown in FIG. 2, to provide a substantially flat cable arrangement wherein the telephone component 12 is disposed generally between the power supply component 14 and the CATV/DATA component 16. In the latter position all of the conductors which comprise the cable 10 are disposed to the same side of a plane, indicated at 48, passing through the points of connection 27 and 29, as shown in FIG. 2. This side-by-side arrangement of the various conductors facilitates coiling or winding the cable 10 on a reel (not shown) which eliminates any substantial risk of kinking conductors. The arrangement of the hinged web connections between the various components is such that the cable 10 may be formed from the cross-sectional configuration shown in FIG. 2 to the cross-sectional configuration shown in FIG. 3 by hinged flexure of the components 14 and 16 at the webs 24 and 26 and relative to the component 12 and to each other, when the cable 10 is pulled from an associated reel. When the cable components are arranged in a generally delta configuration, as shown in FIG. 3, the components 20 and 22 are disposed immediately adjacent each other and the conductors contained therein, which comprise the conductor of the second and third groups 14 and 16 are disposed to one side of the plane 48, whereas the conductors which comprise the first group 12 are disposed to the opposite side of the plane 48. The three components 12, 14 and 16 lie within the boundary of an imaginary circle indicated by broken lines in FIG. 3. This arrangement of the components enables reduction of the major cross-sectional dimension of the cable so that it may pass freely through a circular opening of a predetermined size without encountering substantial frictional resistance. The illustrated cable 10 is paticularly adapted for residential installation and is or may be sized to pass freely through a cylindrical hole of industry standard without substantial frictional resistance.

In addition to shielding the telephone components 12 and the CATV/DATA component 16 from electromagnetic interference, the shield 38 in the power supply component 14 also cooperates with the bare metallic ground conductor 38 to provide an important safety feature. If, during building construction, for example, a metal nail or staple is inadvertently driven through the power supply component and contacts a normally energized conductor, the nail or staple is at ground potential having passed through the metallic shield 38, which is grounded by the ground conductor or wire 36. Thus, the energized conductor will immediately short to ground. If this condition should occur during construction and before the cable is connected to a power source, the system will be shorted when the cable is connected to the power supply source. If the cable is properly handled this arrangement should prevent accidential energization of either the telephone component or the CATV/DATA component by the power supply component when the cable is installed.

If desired, an additional metallic sleeve (not shown) may be provided in the telephone service component 12 within the insulation sheath 18 and in generally coaxially surrounding relation to the conductors 32, 32 to further shield against both conducted and radiated noise interference.

The connecting web portions 24 and 26 comprise weakened regions of the insulation jacket 17 which enable the various free-stripping components 12, 14 and 16 to be readily selectively separated from each other. Thus, either and both of the components 14 and 16 may be readily separated from the component 17 by applying tearing force to end parts of an appropriate two of the three components 12, 14 and 16. The tearing force is, of course, applied in laterally opposite directions relative to the longitudinal axis of the conductor assembly 10.

Referring now to FIG. 4, another electrical conductor assembly or cable embodying the present invention is indicated generally at 10a. The cable 10a is similar in many respects to the cable 10, previously described, and parts of the cable 10a which correspond to parts of the cable 10 are identified by the same reference numeral with a letter "a" suffix. The essential differences between the cable 10a and the previously described cable 10 reside in the construction of the power supply component and its arrangement relative to the telephone and CATV/DATA components, which will be hereinafter described.

The cable 10a has a unitary dielectric insulation jacket indicated generally at 17a which includes distinct first, second and third jacket portions indicated respectively at 18a, 20a and 22a connected by webs 24a and 26a which provide flexible hinge connections between the various jacket portions, substantially as previously described. The illustrated cable 10a is a free-stripping type in that the various distinct tubular portions of the jacket 17a are not adhered to the components contained therein. Thus, when terminal ends of the tubular jacket portions are removed, the electrical conductors contained therein are exposed and are readily separable from each other and from the surrounding portion of the jacket.

The first jacket portion 18a contains a power supply component which comprises a conductor group 14a and includes two insulated color coded solid wire conductors 34a, 34a and an uninsulated or bare metallic ground conductor 36a. An axially elongated shaped insulating spacer 50, which preferably comprises a flexible elongated extrusion of dielectric plastic material, is also located within the jacket first portion 18a and serves to maintain the conductors 34a, 34a and 36a in generally predetermined spaced apart position relative to each other. As shown, the spacer 50 has axially extending arcuate grooves 52, 52 for receiving and retaining the conductors 34a, 34a and another arcuate groove 54 for receiving and containing the bare conductor 36a. A spiral wrapping of metallic foil 38a, preferably copper, is located within the jacket portion 18a and surrounds the conductors which comprise the group 14a. The jacket portion 18a preferably closely surrounds the flexible metallic sleeve 38a, the conductors 34a, 34a and 36a and the spacer 50, substantially as shown in FIG. 4. Thus, the tubular jacket portion 18a cooperates with the spacer 50 to retain the conductors which comprise the power supply component 14a in predetermined spaced relation to each other. Further, the jacket portion 18a cooperates with the spacer to maintain the bare metallic conductor 36a in substantial uninterrupted electrical contacting engagement with the flexible metallic shield 38a along a substantial portion of the length of the bare metallic conductor.

In the illustrated embodiment 10a the second jacket portion 20a contains a telephone component 12a which, as shown, includes eight individually insulated telecommunications conductors 32a, 32a. The illustrated jacket portion 20a also contains a flexible metallic shield 56 formed by a wrapping of metallic foil and surrounding the conductors 32a, 32a. However, the shield 56 may be omitted, if desired. The third jacket portion 22a contains a CATV/DATA component 16a substantially identical to the component 16, previously described.

The webs 24a and 26a are connected to the jacket portion 18a at points of connection indicated at 27a and 29a. The included angle between the points of connection 27a and 29a, as measured about the central axis of the jacket portion 18a and indicated by the letter A in FIG. 4, is preferably at least 60 degrees but not greater than 100 degrees. The length of each web as measured between its point of connection to the jacket portion 18a and its point of connection to an associated jacket portion is preferably as short as possible while allowing hinge flexure of the components between the full line and broken line portions of FIG. 4.

The outer jacket 17a preferably comprises an extruded plastic material, being preferably extruded in the form in which it appears in full lines in FIG. 4, wherein the three service components are maintained in a Delta cross-sectional configuration relative to each other. In the latter position the three components lie within an imaginary circle, such as shown in broken lines in FIG. 4, which may, for example, represent a typical opening through which the cable 10a may be pulled. When the cable 10a is in the position shown in FIG. 4, the second and third groups of electrical conductors 12a and 16a are disposed to one side of an imaginary plane 48a passing through the points of connection 27a and 29a. The conductors which comprise the first group 14a are disposed to the opposite of the plane 48a. When the jacket 18a and 22a portions are flexed about the webs 24a and 26a and to their respective broken line positions of FIG. 4, all of the conductors which comprise the first, second and third groups of conductors are generally disposed to the same side of the plane 48a and lie in generally side-by-side or in-line relation to each other so that the cable 10a may be would onto a reel (not shown) or the like with each of the conductors being wound to approximately the same radius as the others, whereby the risk of kinking the various conductors is minimized.

The cable of the present invention facilitates cost-saving installation of power, video/computer and telephone service wiring. The telephone component facilitates the installation of many circuits for miscellaneous control, monitor or audio applications, as may be required.

The invention has been illustrated with reference to cable assemblies having particular arrangements of electrical conductors, however, it should be understood the size, number and type of electrical conductors which comprise the various cable components may vary and that further modified forms of the cable are contemplated within the scope of the invention.