GB2149502A

GB2149502A - Connecting electric cables

Info

Publication number: GB2149502A
Application number: GB08428167A
Authority: GB
Inventors: Graeme G Rennie
Original assignee: Cable Makers Australia Pty Ltd
Current assignee: Cable Makers Australia Pty Ltd
Priority date: 1983-11-08
Filing date: 1984-11-07
Publication date: 1985-06-12
Also published as: GB2149502B; DE3440711A1; DE3440711C2; GB8428167D0; JPS60241612A; JPH0338712B2; GB8329727D0; AU3514784A; AU572912B2

Abstract

In the automated production of electric plug assemblies the identity and positioning of the exposed insulated conductors 12 of a length of multi-conductor cable 11 prior to automatically connecting the conductors to the plug pin terminals is effected by directing white light from source 4 on to the exposed insulated conductors; dividing light reflected into three separate branches eg by fibre optic probe 5; filtering the light from each branch at 6 to provide a different primary colour; determining the intensities of the filtered primary colours by means of detectors 8; identifying each exposed insulated conductor by comparison of the reflected colours of the insulated conductors with each other and with reference values, and automatically positioning the exposed insulated conductors having regard to the identification e.g. by rotating the cable. <IMAGE>

Description

SPECIFICATION Electric cables This invention relates to electric cables and is especially, but not exclusively, concerned with the use of electric cables in electric plug assemblies of the kind in which the conductors of a length of flexible insulated multi-conductor cable are electrically connected to appropriate conductor terminals of the plug pins and these conductor/pin connections are encapsulated in a moulded plug body of electrically insulating material which is permanently bonded to the insulating covering of a part of the length of cable and from which an appropriate length of each pin protrudes. Electric plug assemblies of this kind will hereinafter, for convenience, be referred to as "of the kind described".

In the manufacture of an electric plug assembly of the kind described - and in the manufacture of other electrical apparatus in which the conductors of a length of multi-core electric cable are to be electrically connected to associated terminals or conductors - it is necessary to identify each conductor of the cable and to position the conductors in such a way that each can be readily connected to its associated terminal or conductor.Whilst, in many circumstances, visual identification and manual positioning of the cable conductors will suffice, where an electric plug assembly or other electric apparatus to which a length of multi-conductor electric cable is to be connected is being manufactured in an automated production line, visual identification and manual positioning of the cable conductors cannot be effected quickly enough to keep pace with the automatically operated manufacturing steps, for example, in automated manufacture of electric plug assemblies of the kind described a cut-back length of multi-conductor electric cable with exposed lengths of its conductors identified and appropriately positioned relative to one another is required every few seconds.

It is an object of the present invention to provide an improved method of automatically identifying and positioning exposed lengths of insulated conductor of a multi-conductor electric cable, relative to one another and/or relative to terminals or other conductors to which they are to be connected, each of which cable conductors has an insulating covering of a colour or colours differing from that or those of the insulating covering of the other cable conductor or conductors, which method is especially, but not exclusively, suitable for use in automated production of electric plug assemblies of the kind described.

According to the invention, the improved method comprises directing white light on to the exposed lengths of insulated conductor; dividing light reflected from the insulating coverings of the exposed conductor lengths into a plurality of separate branches equal in number to the number of exposed lengths of insulated conductor; filtering the light in each branch to provide a primary colour of the visible spectrum, the primary colour of each filtered branch being different from that of the or each other branch; determining, for the covering layers of the exposed lengths of insulated conductor, the intensities of the filtered primary colours thereby to identify each exposed length of insulated conductor; and automatically positioning the exposed lengths of insulated conductor relative to one another and/or relative to terminals or other conductors to which they are to be connected having regard to said identification.

Where the multi-conductor electric cable is a three core electric wiring cable of the kind employed in an electric plug assembly of the kind described, one conductor of the cable having an insulating covering coloured brown (the live conductor), one conductor having an insulating covering coloured blue (the neutral conductor) and one conductor having an insulating covering which is coloured with green and yellow stripes (the earth conductor), preferably the three branches of light reflected from the exposed lengths of insulated conductor are so filtered as to provide as the three primary colours, red, blue and green.

Preferably, light reflected from the exposed lengths of insulated conductor is detected by means of a fibre optic probe consisting a multiplicity of optical fibres and the optical fibres of the probe are divided into the separate branches, each of which is connected to a colour separation filter.

Preferably, also, the intensity of each of the filtered primary colours, say, red, blue and green, of light reflected from the exposed "lengths of conductor is measured using a solid state photo sensitive device such as pin photodiode. Focussing lenses may be positioned between the colour separation filters and the solid state photo sensitive devices. Identification of each exposed length of insulated conductor can thus be achieved by determining the spectral reflectance "finger-point" of each exposed length of insulated conductor.

The solid state photo sensitive devices are preferably connected to a microprocessor which will record and compare the intensities of the filtered primary colours both between the exposed lengths of insulated conductor themselves and between each exposed length of insulated conductor and associated reference data. The microprocessor is preferably operatively connected to apparatus which controls means for driving the multi-conductor cable in rotation about its axis until the exposed lengths of insulated conductor are appropriately positioned relative to one another and/or relative to the associated terminals or other conductors to which they are to be connected.

It will be appreciated that the colours of the exposed lengths of insulated conductor may vary slightly from one length of cable to another and this may necessitate a teach facility in the microprocessor system to enable the vision system to be timed for each particular length of cable.

Any convenient white light source may the employed for directing white light on to the exposed lengths of insulated conductor but preferably a voltage controlled tungsten-halogen white light source is used.

The invention also includes apparatus for automatically identifying and positioning exposed lengths of insulated conductor of a multi-conductor electric cable relative to one another and/or relative to terminals or other conductors to which they are to be connected, by the improved method hereinbefore described.

The invention is further illustrated by a description, by way of example, of preferred apparatus for automatically identifying and positioning exposed lengths of the three insulated conductors of an electric wiring cable relative to associated plug pin terminals prior to electrically connecting the conductors to the plug pin terminals, with reference to the accompanying drawing which shows a diagrammatic representation of the preferred apparatus.

Referring to the drawing, the preferred apparatus comprises as tubular cable grip 1 which is adapted to grip a length of multi-conductor electric cable 11 and which can be rotatably driven about its axis by a motor (not shown). Associated with, but separately formed with respect to, the cable grip 1 is a locating cone 2 to which the conductors 13 of three exposed lengths 12 of insulated conductor of the multi-conductor electric cable 11 can be secured at uniformly spaced positions around its periphery by means of clamps 3. One exposed length 12 of insulated conductor of the cable 11 has an insulating covering coloured brown (the live conductor), one exposed length has an insulating covering coloured blue (the neutral conductor) and one exposed length has an insulating covering which is coloured with green and yellow stripes (the earth conductor).

A voltage controlles tungsten-halogen white light source 4 is positioned on one side of the locating cone 2 and positioned to receive light reflected from the insulating coverings of the exposed conductor lengths 12 is a fibre optic probe 5 comprising a multiplicity of optical fibres. The oprical fibres of the probe 5 are divided into three separate branches, each of which is connected to a fixed colour filter 6 which will filter the light in its associated branch to provide a primary colour of rhe visible spectrum. One of the filters 6 provides rhe primary colour red, another provides the primary colour blue and the third provides the primary colour green.

Associated with each of the filters 6 is a focusing lens 7 by means of which the primary colour can be focussed on to a solid state photo sensitive device such as a pin photodiode 8.

The three pin phorodiodes 8 are connected to a micrcprocessor 9 which will record and compare the intensities of the filtered primary colours, both between the exposed lengths of insulated conductor themselves and between each exposed length of insulated conductor and associated reference data. The microprocessor is operatively connected to a shaft position encoder 10 and to means (not shown) which controls the motor (not shown) for driving the cable grip 1, and hence the multi-conductor cable 11, in rotation about its axis.

In use, the mulri-conductor cable 11 is gripped in the cable grip 1 with the conductors 13 of three exposed lengths 12 of its insulated conductors clamped to the locating cone 2 by clamps 3 and white light is directed on to the exposed lengths 12 of insulated conductor from the source 4. Light reflected from the exposed lengths 12 of insulated conductor is detected by the fibre optic probe 5 and is divided into three branches in which the light is filtered by the filters 6 to provide three filtered primary colours red, blue and green. The intensity of each of the three filtered primary colours is measured by the pin photodiodes 8 and these intensities are recorded and compared, both between the exposed lengths of insulated conductor themselves and between each exposed length of insulated conductor and associated reference data, by the microprocessor 9. The microprocessor 9 then automatically operates the control means to drive the multi-conductor cable 11 rotatably about its axis until the exposed lengths of insulated conductor are appropriately positioned relative to the associated plug pin terminals to which they are to be connected.

Claims

1. A method of automatically identifying and positioning exposed lengths of insulated conductor of a multi-conductor electric cable, relative to one another and/or relative to terminals or other conductors to which they are to be connected, each of which cable conductors has an insulating covering of a colour or colours differing from that or those of the insulating covering of the other cable conductor or conductors, which method comprises directing white light on to the exposed lengths of insulated conductor; dividing light reflected from the insulating coverings of the exposed conductor lengths into a plurality of separate branches equal in number to the number of exposed lengths of insulated conductor; filtering the light in each branch to provide a primary colour of the visible spectrum, the primary colour of each filtered branch being different from that of the or each other branch; determining, for the covering layers of the exposed lengths of insulated conductor, the intensities of the filtered primary colours thereby to identify each exposed length of insulated conductor; and automatically positioning the exposed lengths of insulated conductor relative to one another andl or relative to terminals or other conductors to which they are to be connected having regard to said identification.

2. A method as claimed in Claim 1, wherein the multi-conductor electric cable is a three core electric wiring cable of the kind employed in an electric plug assembly of the kind described, one conductor of the cable having an insulating covering coloured brown (the live conductor), one conductor having an insulating covering coloured blue (the neutral conductor) and one conductor having an insulating covering which is coloured with green and yellow stripes (the earth conductor), and wherein the three branches of light reflected from the exposed lengths of insulated conductor are so filtered as to provide as the three primary colours, red, blue and green.

3. A method as claimed in Claim 1 or 2, wherein light reflected from the exposed lengths of insulated conductor is detected by means of a fibre optic probe comprising a multiplicity of optical fibres and the optical fibres of the probe are divided into the separate branches, each of which is connected to a colour separation filter.

4. A method as claimed in any one of the preceding Claims, wherein the intensity of the filtered primary colour of light reflected from each exposed length of conductor is measured using a solid state photo sensitive device.

5. A method as claimed in Claim 4, wherein the solid state photo sensitive devices are cohs of insulated conductor themselves and between each exposed length of insulated conductor and associated reference data.

6. A method as claimed in Claim 5, wherein the microprocessor is operatively connected to apparatus which controls means for driving the multi-conductor cable in rotation about its axis until the exposed lengths of insulated conductor are appropriately positioned relative to one another and/or relative to the associated terminals or other conductors to which they are to be connected.

7. A method as claimed in any one of the preceding Claims, wherein the white light source is a voltage controlled tungsten-halogen white light source.

8. Apparatus for automatically identifying and positioning exposed lengths of insulated conductor of a multi-conductor electric cable, relative to one another and/or relative to terminals or other conductors to which they are to be connected, each of which cable conductors has an insulating covering of a colour or colours differing from that or those of the insulating covering of the other cable conductor or conductors, which apparatus comprises a source of white light for directing on to the exposed lengths of insulated conductor; a fibre optic probe comprising a multiplicity of optical fibres for detecting light reflected from the insulating coverings of the exposed conductor lengths; and for dividing said reflected light into a plurality of separate branches equal in number to the number of exposed lengths of insulated conductor; filtering means associated with each branch for providing a primary colour of the visible spectrum, the primary colour of each filtered branch being different from that of the or each other branch; means associated with each branch for measuring the intensity of the filtered primary colour; and a microprocessor to which said intensity measuring means are operatively connected, which will record and compare the intensities of the filtered primary colours both between the exposed lengths of insulated conductors themselves and between each exposed length of insulated conductor and associated reference data, and which is operatively connected to apparatus for controlling means for driving the multiconductor cable in rotation about its axis until the exposed lengths of insulated conductor are appropriately positioned relative to one another and/or relative to the associated terminals or other conductors to which they are to be connected.

9. Apparatus as claimed in Claim 8, wherein the means for measuring the intensity of the filtered primary colours comprises solid state photo sensitive devices.

10. Apparatus as claimed in Claim 9, wherein focusing lenses are positioned between the colour separation filters and the solid state photo sensitive devices.

11. Apparatus as claimed in any one of Claims 8 to 10, wherein the white light source is a voltage controlled tungsten-halogen white light source.

12. Apparatus for automatically identifying and positioning exposed lengths of insulated conductor of a multi-conductor electric cable, relative to one another and/or relative to terminals or other conductors to which they are to be connected, each of which cable conductors has an insulating covering of a colour or colours differing from that or those of the insulating covering of the other cable conductor or conductors, which apparatus is substantially as hereinbefore described with reference to and as shown in the accompanying drawing.

13. A method of automatically identifying and positioning exposed lengths of insulated conductor of a multi-conductor electric cable, relative to one another and/or relative to terminals or other conductors to which they are to be connected, each of which cable conductors has an insulating covering of a colour or colours differing from that or those of the insulating covering of the other cable conductor or conductors, which method is substantially as hereinbefore described with reference to the accompanying drawing.