Cable and method of manufacturing the same

Abstract

A cable includes a cable sheath in which are embedded a plurality of insulated conductors at least two of which are helically twisted, the cable being provided with visible markings that indicate where one can electrically engage a selected one of the conductors by an insulation-piercing contact. The cable is formed by arranging a plurality of insulated conductors in a light-transmitting synthetic plastic sheath layer, two or more of the insulated conductors being helically twisted about a longitudinal axis, which cable is optically scanned to determine locations at which contiguous portions of the twisted insulated conductors are superposed orthogonally relative to a reference plane, whereupon markings are formed on the cable sheath layer at locations laterally spaced from the contiguous conductor portions, whereby a selected one of the twisted conductors may be engaged by an insulation-piercing contact.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and advantages of the invention will become apparent from a study of the following specification, when viewed in the light of the accompanying drawing, in which:

FIG. 1 is a perspective view of the cable of the present invention when in the initial unmarked condition, and

FIG. 2 is a corresponding view of the cable of FIG. 1 when provided with markings illustrating the penetration locations for the insulation-piercing contacts;

FIG. 3 is a corresponding perspective view illustrating the manner of penetration of the cable by the insulation piercing means;

FIG. 4 a is a sectional view taken along the line 4a-4a of FIG. 3, and FIG. 4b is an enlargement of the circled portion of FIG. 4a;

FIGS. 5, 6 and 7 are top plan views of the cables of FIGS. 1, 2 and 3, respectively; and

FIGS. 8 and 9 are sectional views of two modifications of the cable of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring first more particularly to FIG. 1, the cable C includes a cable sheath 1 that encloses a plurality of conductors 2 which are each provided with an outer insulation layer 3. The cable is made in the form of a flat-strip cable that has fourteen conductors 2a to 2n. This number is to be understood just as an example and can be varied within the context of the invention. The diameters of the conductors 2 of the cable can be equal or also different.

Conductors 2a to 2n here are grouped in two groups 4, 5 with seven conductors each 2a to 2g and 2h to 2n, whereby between the two groups there is an interval that goes beyond the distance of conductors 2 within the groups 4, 5, which interval is bridged by a cable sheath strip 6. A first group of four conductors 2a to 2g are placed parallel to each other. In the second group of conductors 2, the five conductors 2h to 2l lie parallel to each other. Conductors 2k and 2m have a larger diameter than conductors 2a to 2j. At least two of the conductors—the conductors 2m, 2n—moreover, are twisted together with each other (twisted pair), whereby this twisted unit 7 again as a whole is arranged parallel to the other conductors.

It is first of all essential to make sure that at least two of the conductors 2 of the cable are twisted together with each other. As an alternative, one could also arrange in the cable several twisted-together conductor pairs, preferably in one plane next to each other (now shown here). Moreover, it might also be conceivable to twist more than two conductors together with each other.

The cable here has a particularly preferred flat-strip cable shape. Alternate shapes are conceivable, for example, especially generally flat cables C′ having an elliptical cross-sectional configuration (FIG. 8). When round cables C″ are used (FIG. 9), it is recommended to provide a polarization means, such as a radially outwardly directed integral web portion 1a on the outer sheath 1, thereby to provide a reference plane relative to the cable. In each case, the cable sheath 1 consists of a transparent or translucent material, something that is illustrated, for example, in FIGS. 4 to 7.

Cable C in FIG. 1 is subjected to a last finishing step to be able to contact not only conductors 2a to 2l but also the mutually twisted-together conductors 2m, 2n by means of insulation-penetrating contacts (IDC contacts) 8 (FIG. 3, FIG. 7). One now first of all determines at which places the mutually twisted-together conductors 2m, 2n can be contacted with the insulation-penetrating contacts. As a rule, that will be the places 9 or 10 that are arranged with relation to the direction of movement of the insulation-penetrating contacts and that are either flush with each other or that are arranged next to each other. At the desired places, cable sheath 1 is then provided once or preferably, in the area of each spiral, with markings 11.

Here it is desirable to contact the mutually twisted-together conductors 2m, 2n at those places where they are positioned above each other normal to the reference plane of the cable. These are the places 9 where the conductors 2m, 2n are flush with each other in the direction of the movement of the IDC contacts 8. Then the places 9, which are to be contacted later on, are in each case provided with at least one of the markings 11.

Markings 11 are easily recognizable in the preferred exemplary embodiment and are clearly shaped in the middle cable sheath strip 6 as penetrations (FIG. 2). It is, however, basically also conceivable to put markings of some other kind on the cable sheath. The important thing is that the markings 11 must be in a fixed relation to the spiral arrangement and the alignment of the mutually twisted-together conductors 2m, 2n. Here one might mark the places that are to be contacted with the insulation-penetrating contacts or areas of the cable in the latter's X longitudinal direction, something that is particularly clearly visible in FIG. 7. Here markings 11 are placed laterally opposite contact place 9 in the cable sheath strip 6.

The marking is preferably done automatically by means of a device for the transverse illumination of the cable, whereby the cable, for example, is transversely illuminated from one side with a light source that can be moved with relation to the cable. With the help of a likewise relatively movable sensor, one determines on the other side of the cable when the conductors 2m, 2n are directly above each other. That is possible because the light falling into the sensor depends on whether the two twisted-together conductors are positioned above each other or next to each other. The marking is set when a maximum of light incidence has been determined.

The contacting is preferably done by means of a connection device with a preferably producible housing 12, 13 and with the IDC contacts 8 (preferably piercing contacts), which, for example, can be attached to the lid. Housing 12, 13 is aligned on one of the markings 11. For example, it is conceivable that the lower part of the housing 12 has a projection 14 that is so aligned as to engage the penetration that forms markings 11 so that the correct alignment of the connection device 8 will be ensured, so to speak, “automatically” during the contacting of the cable (FIG. 7). Thus, when the projection 14 extends within a perforation 11 (FIG. 4b), the insulation-piercing contact 8a engages the conductor 2m. At another longitudinally-spaced location between the markings 11, the conductor 2n is arranged uppermost for engagement by an insulation-piercing contact.

While in accordance with the provisions of the Patent Statutes the preferred forms and embodiments of the invention have been illustrated and described, it will be apparent to those skilled in the art that changes may be made without deviating from the invention described above.

Claims

1. An electrical cable (C) comprising: (a) a plurality of electrical conductors (2);(b) a plurality of layers of insulation material (3) enclosing each of said conductors, thereby to define a plurality of insulated conductors;(c) a cable sheath layer (1) enclosing said insulated conductors, said cable sheath layer being formed from a light-transmitting synthetic plastic material; and(d) a plurality of visible markings (11) arranged on said cable sheath layer opposite locations (9) at which said cable sheath layer and one of said insulation layers may be severed by an insulation-piercing contact (8) to effect electrical engagement with a selected one of said conductors.

2. An electrical cable as defined in claim 1, wherein a pair of said insulated conductors (2m, 2n) are helically twisted together within said cable sheath layer, thereby to define on said twisted insulated conductors a plurality of characterizing insulation-piercing locations (9, 10) relative to the other insulated conductors.

3. An electrical cable as defined in claim 2, wherein said insulated conductors are divided into two groups one of which includes said helically twisted insulated conductors, said two groups of insulated conductors being joined by an intermediate strip portion (6) of said cable sheath layer, said visible markings being carried by said sable sheath layer intermediate strip portion.

4. An electrical cable as defined in claim 2, wherein said markings comprise perforations (11) contained in said intermediate strip portion.

5. An electrical cable as defined in claim 2, wherein one marking is provided for each longitudinal 360° helical turn of said two twisted insulated conductors.

6. An electrical cable as defined in claim 5, and further including means defining a longitudinal reference plane relative to said two twisted insulated conductors, said insulation-piercing locations (9, 10) being defined by locations at which contiguous portions of the twisted insulated conductors are superposed orthogonally relatively to said reference plane.

7. An electrical cable as defined in claim 6, wherein said cable C is flat, all of said insulated conductors being contained in a plane that defines said reference plane.

8. An electrical cable as defined in claim 7, wherein said cable has an elliptical cross-sectional configuration, said cable including an integral outwardly-directed web portion defining said reference plane.

9. An electrical cable as defined in claim 6, wherein said cable has a round cross-sectional configuration, said cable sheath layer having an integral radially-outwardly directed integral web portion defining said reference plane.

10. An electrical cable as defined in claim 5, wherein said markings are provided at locations opposite positions at which the same cable is superposed over the companion twisted cable.

11. A method for producing an electrical cable (C), comprising: (a) providing a plurality of parallel insulated conductors (2);(b) embedding the insulated conductors in a cable sheath layer (1) of light-transmitting synthetic plastic material in such a manner as to define a given longitudinal reference plane;(c) illuminating the cable in a direction normal to said reference plane;(d) sensing longitudinally-spaced portions of a selected one of the insulated conductors; and(d) visibly marking (11) the cable sheath layer at locations laterally spaced from said longitudinally-spaced portions, whereby said cable sheath layer and the conductor insulation layer of said selected conductor may be severed by an insulating-piercing contact (8) to effect electrical engagement of the contact with said selected conductor.

12. A method for producing an electrical cable (C), comprising: (a) providing a plurality of parallel insulated conductors (2) two of which (2m, 2n) are helically twisted about a longitudinal axis;(b) embedding the insulated conductors in a cable sheath layer (1) layer of light-transmitting synthetic plastic material in such a manner as to define a given longitudinal reference plane;(c) illuminating the cable in a direction normal to said reference plane;(d) sensing the positions at which portions of one of the twisted insulated conductors is directly superposed over the other insulated conductor relative to said reference plane; and(d) marking the cable at locations (11) laterally spaced from said longitudinally spaced locations, whereby said conductive sheath and one of said insulation layer may be severed by an insulating-piercing contact (8) to effect electrical engagement of the contact with a selected conductor.