AU621743B2

AU621743B2 - Electrical connector

Info

Publication number: AU621743B2
Application number: AU54548/90A
Authority: AU
Inventors: Allan Greenfield
Original assignee: TRIANGLE CABLES Pty Ltd
Current assignee: TRIANGLE CABLES Pty Ltd
Priority date: 1990-04-30
Filing date: 1990-04-30
Publication date: 1992-03-19
Anticipated expiration: 2010-04-30
Also published as: AU5454890A

Description

I

SI

AUSTRALIA

621743 Patents Act COMPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number: Lodged: Complete Specification Lodged: 0 00 0 00 0000 Priority 0 00 a00 a Related Art: 0000 00 *0 0 Accepted: Published: 000* 0 0000 *000 0 00 t 0 Name(s) of Applicant(s): Address(es) of Applicant(s): APPLICANT'S REF.: TRIANGLE CABLES PTY. LTD.

Triangle Cables House, 10 Elizabeth Street, Kensington, Victoria 3031, Australia.

4768 Actual Inventor(s): Address for Service is: PHILLIPS, ORMONDE AND FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne, Australia, 3000 Complete Specification for the invention entitled: "ELECTRICAL CONNECTOR" The following statement is a full description of this invention, including the best method of performing it known to applicant(s): P19/3/84

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ELECTRICAL CONNECTOR This invention relates to electrical connectors, and in particular to an electrical plug or socket connector for connecting to or interconnecting electrical circuits. The invention is applicable to a plug or socket connector for attachment to an electrical extension lead or electrical applicance lead, and it will be convenient to hereinafter describe the invention in relation to that exemplary application. However, it is to be appreciated that the invention is not limited to that application.

Various electrical connectors, such as plugs and sockets, incorporate facilities for indicating at least the presence and/or absence of electrical quantities, such as o000 oo current and/or voltage at the connectors. Such connectors o000 typically include indicator means responsive to an electrical o quantity to provide one or more indications representative of o o a value or level of electrical quantity. Thus, in a practical example of such a connector, the indicator means can include one or more indicator lights which illuminate in a predetermined manner to visually indicate a normal and/or abnormal current and/or voltage quantity value.

However, a disadvantage with at least some of the prior connectors is that they may indicate a normal condition even 0000 a though fault conditions, of incorrect or incomplete electrical conductor connection to the connector, exist. Such fault o*t conditions include reversed conductor connections to "active" and "neutral" terminals of the connector, and a break in, or open circuit to, the "earth" terminal of the connector.

Australian patent 543298 discloses a plug or socket connector which attempts to overcome this problem at least in some circumstances in which there is a disconnection or faulty connection of the conductor to the "earth" terminal of the connector. The connector of that patent has visual means including a light source which, when illuminated indicates reliable or normal power and earth connections. In addition, a shunt resistance and series impedance is provided in circuit with the active and earth terminal connections and visual means to ensure that, in the event of a faulty earth 39 connection, the light source does not illumninate due to 2 induction within the conductors of an associated lead.

At least one disadvantage with this connector is that the cause of failure of the light source to illuminate is not always immediately apparent. In that regard, lack of illumination may be due to a fault condition in the power or earth connections, or an absence of power to the connector.

In addition, this connector does not provide an indication of the condition of the active and neutral terminal connections, and in particular whether or not these terminal connections are reversed.

It is an object of the present invention to alleviate this disadvantage through the provision of an electrical connector incorporating relatively simple electrical connection condition indicating facilities.

With that object in mind, the present invention provides an electrical connector for connection to an alternating current power supply including: a connector body; electrical terminal means carried by the connector body and providing separate power supply, power return and earth terminals for 20 connection to respective electrical conductors of the power supply; and indicator means carried by the connector body, the indicator means including a fault indicator circuit connected Sto the terminal means and being operable upon connection of the power supply, power return and earth terminals to the 25 electrical conductors to provide an indication in the event that the connections of the respective electrical conductors to the power supply and power return terminals are reversed or S* in the event of loss of an earth connection to the earth terminal, the fault indicator circuit having an indicator element with bi-modal operation, each operation defined by a different activation duration of the indicator element respectively indicative of reversed power supply and power return terminal connections and loss of an earth connection to the earth terminal, as the case may be.

In one embodiment, the indicator element is an indicator light operating by repeatedly flash illuminating for different durations, respectively, indicating the reversed power supply and power return terminal connections, and the loss of an PA earth connection to the earth terminal.

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o* C Sa aee a In one embodiment, the indicator element is connected between the power return and earth terminals. The fault indicator circuit in this embodiment further has a rectifying diode connected in series with the indicator element and a shunt capacitor connected across the indicator element. In this embodiment, the fault indicator circuit also has a series impedence connected with the indicator element for regulating the actuation duration of the indicator element. In one embodiment, the series impedence is provided by at least one resistor. One resistor is connected between the power return terminal and the indicator element in this embodiment for regulating, together with the capacitor, the actuation duration of the indicator element when indicating reversed power supply and power return terminal connections. A further 15 resistor is connected between the power supply terminal and the indicator element in this embodiment, the resistors and shunt capacitor together regulating the actuation duration of the indicator element when indicating the loss of an earth connection to the earth terminal.

The indicator means is also preferably operable to indicate a reliable electrical power connection between the terminals and the electrical conductors. To that end, the indicator means preferably includes a voltage indicator circuit. The voltage indicator circuit is preferably 25 connected in parallel with the fault indicator circuit. That circuit has at least one indicator light illuminating to provide a visual indication of the reliable electrical power connection.

In one embodiment, the indicator light providing the indication of the reliable electrical power connection is connected between the power supply and power return C e e Ce e e a C e oe u o ©r r e c~o 4 terminals. The power indicator circuit further has a series impedence connected with the indicator light in this embodiment. That impedence is provided by at least one resistor in one embodiment.

The following description refers to a preferred embodiment of the electrical connector of the present invention. To facilitate an understanding of the invention, reference is made in the description to the accompanying schematic drawing and circuit diagram of the connector. It is to be understood that the connector is not limited to the preferred embodiment as hereinafter described and as illustrated in the drawing.

Referring t, the drawing, there is generally shown an KW a 4a a.

at a trrt t a I t electrical connector 1 in the form of an electrical plug or socket connector. This connector 1 is particularly suitable for use as a plug or socket connector for an extension or appliance lead (not shown). Alternatively, the connector 1 can be used alone as a testing connector for plugs, sockets and power points.

The connector 1 includes a body 2. The connector body 2 is of any suitable construction having regard to the intended application of the connector i, as will be well appreciated by those skilled in the relevant art. In the exemplary application, the body 2 acts as a casing. The body 2 is of a unitary construction, or fabricated from a plurality of parts permitting interior access thereto.

o0 The connector body 2 is composed of any suitable to** material. Again, in the exemplary application, the body 2 is conveniently composed of plastics material. At least a S portion of that material is transparent, in this preferred Sembodiment, to enable visual inspection of the interior of the 4 body 2.

The connector 1 includes electrical terminal means 3 having terminals 4A, 4N and 4E for connection to respective oO electrical conductors C connected or connectable to a power supply. In alternative embodiments, the terminals 4A, 4N, 4E to are interior and/or exterior of the connector body 2, with the body 2 having provision where necessary for electrical 4 conductor access to the terminal 4A, 4N, 4E. Thus, in one embodiment, all the terminals 4A, 4N, 4E are exterior of the body 2, in another embodiment they are all interior of the Ott$ 6 4 4 body 2, and in yet another embodiment at least one terminal 4 4a s• 4A, 4N or 4E is interior and at least one terminal 4A, 4N or 4E is exterior of the body 2.

The terminals 4A, 4N, 4E are of any suitable construction having regard to the intended application of the electrical connector 1. In the exemplary application, the terminals 4A, 4N, 4E may include terminal pins (not shown) protruding exterior of the body 2 when the connector 1 is in the form of an electrical plug, or terminal sockets (not shown) interior of the body 2 when the connector 1 is in the 39 form of an electrical socket. When the connector 1 is in the 111- lin;cnr~--=r~l;~-a~ form of an electrical plug, and connected to an extension lead, then the conductors C will be removably connectable to the terminals 4A, 4N, 4E and further conductors (not shown) forming part of the lead will be permanently connected to the terminals 4A, 4N, 4E. When in the form of an electrical socket, and connected to an extension lead, then the conductors C are part of the lead and permanently connected to the terminals 4A, 4N, 4E. When the conductor 1 is in the form of a testing connector (plug or socket) then the conductors C l0 are removably connectable to the terminals 4A, 4N, 4E, and no further conductors need be connected to those terminals.

As will be well appreciated by those well skilled in the relevant art, the terminals 4A, 4N, 4E are conveniently eo identified as "active", "neutral" and "earth" terminals, respectively, for connection to an AC power supply provided through conductors C. It should be appreciated that in other applications of the connector i, alternative or additional o terminals may be provided.

The connector 1 further includes an indicator means 5 at least substantially contained within the connector body 2, although of course the indication provided thereby is detected exterior of the casing. In this embodiment, the indicator means 5 provides a visual indication of faulty connections between electrical conductors C with the terminals 4A, 4N, 4E, as well as a reliable electrical voltage connection between t the terminals 4A, 4N, 4E and the electrical conductors C. It is to be appreciated that, in alternative embodiments, the indication provided may have an audible output, a combined S. visible and audible output, or a switch or relay output.

(I CC' '3Q The indicator means 5 includes a fault indicator circuit 6 for indicating faulty electrical conductor connections, and in particular an open connection at the earth terminal 4E and reverse connections of the electrical conductors C to the active and neutral terminals 4A, 4N.

Fault indicator circuit 6 includes circuit line 7 connecting terminals 4A, 4N, 4E, the line 7 extending between the terminals 4A, 4N and the terminal 4E being connected to the circuit line 7 at common point 8. The indicator light 9 39 is contained in the line 7 between the terminals 4 and 4E.

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:1 The indicator light 9 is a small "red" neon light in this embodiment, although other indicator lights, such as light emitting diodes, may be provided in alternative embodiments.

The fault indicator circuit 6 also includes a signal rectifying diode 10 in series with the indicator light 9 in the circuit line 7, and providing half wave rectification of an AC wave form signal in the circuit line 7. The circuit 6 further includes shunt capacitor 11 across the indicator light 9 and a series impedence 12 in the circuit line 7. The series impedence 11 comprises resistors 13, 14 in this embodiment.

The rectifying diode 10, the shunt capacitor 11 and the series impedence 12 function to cause repeated "flash" illumination of the indicator light 9 when indicating faulty sa o o electrical conductor connections. In addition, the resistors S13, 14 are selected so that the flash illumination 0906 characteristics differ between indications of those faulty 060 connections. That is, the indicator light 9 flashes 0 differently when indicating an open connection at the earth o o00 0: terminal 4E and when indicating reversed connections of the conductors C to the active and neutral terminals 4A, 4N. In this embodiment, the different illuminations arise from the rate at which the indicator light 9 extinguishes following ooo o" each illumination, the light 9 extinguishing more slowly when *0e0 00 indicating an open connection at the earth terminal 4E so as 0* to appear to flash slowly, and extinguishing more rapidly when indicating reversed connections at the active and neutral terminals 4A, 4N so as to appear to flash more rapidly. That is achieved by locating the resistor 13 between the neutral au and earth terminals 4N, 4E and the resistor 14 between the active and earth terminals 4A, 4E.

In this embodiment, the indicator light 9 is a small N12 neon light rated at approximately 50 volts. The rectifying diode 10 is a IN 4004 d-.de, the shunt capacitor 11 is a 0.47 microfarad, 100 volt high temperature capacitor, the resistor 13 is a 270 K ohms resistor and the resistor 14 is a 2.7 M ohms resistor, in this embodiment.

The indicator means 5 also includes a voltage indicator circuit 15 for indicating a reliable electrical voltage 39 connection at the terminals 4A, 4N, 4E. In the exemplary ;1I;i

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7 ic application, the circuit 15 indicates that the connector 1 is connected to a single phase, 240 volt, AC electrical power supply through conductors C.

The voltage indicator circuit 15 includes a circuit line 16 connecting the terminals 4A, 4N, and containing indicator light 17. The light 17 is conveniently of the same type as the light 9. In a preferred embodiment, the light 17 is a small N:11 "green" neon light rated at approximately 50 volts.

The voltage indicator circuit 15 also includes a series impedence 18 in the circuit line 16. The impedence 18 comprises a resistor 19, in this embodiment. The resistor 19 is a 270 K ohms resistor, in this embodiment.

The voltage indicator circuit 15 operates to cause OQoo 0o0o "steady" illumination of the indicator light 17 when *too 0'0 indicating a reliable electrical voltage connection at the 00t0 0: terminals 4A, 4N, 4E.

In operation of the preferred embodiment of th, 0 o connector 1 as outlined above, the terminal means 3 is connected to a power supply, such as a 240 volt (nominal) AC mains power supply through the conductors C.

The provision of that power supply causes current to flow from the terminal 4A through the circuit line 16 to the terminal 4N, thereby illuminating the indicator light 17.

0004 Steady illumination of the light 17 continues until the power supply is removed.

tt Provided no fault connections exist whilst there are proper connections to the terminals 4A, 4N, 4E) the indicator light 9 will remain extinguished. Current from the terminal 4A to the circuit line 7 will return through the '3n common point 8 to the terminal 4E.

Where an open connection occurs between the conductors C and the earth terminal 4E, so that the current return path is removed, the current from the terminal 4A flows through the circuit 6 to the terminal 4N. This in turn causes the indicator light 9 to illuminate. A "slow flash" illumination occurs since current flows through both the resistors 13, 14 within the circuit 6.

Where the connection of the electrical conductors C to 39 the terminals 4A, 4N are reversed, then current from the power 8 supply will flow from the terminal 4N through the circuit to the terminal 4A, again illuminating the light 9 to indicate the electrical power connection between the conductors C and the terminal means 3.

In addition, the current from the terminal 4N flows through the circuit 6 to the common point 8 and then to the terminal 4E. This causes the indicator light 9 to illuminate. A "rapid flash" illumination occurs since current flows only through the resistor 13 within the circuit 6.

The connector of the present invention provides a relatively simple yet effective indication of faulty electrical conductor connections with the connector.

It is to be understand that various modifications and/or S alterations may be made to the electrical connector without trtr a departing from the present invention as defined in the claims I appended hereto. By way of example an alternative connector having at least some of the attributes of the connector Salt embodiment described above is disclosed in Australian patent application PJ 4888. The disclosure of the connector of that patent application is included herein by way of reference.

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Claims

2. An electrical connecter as claimed in claim i, wherein S the indicator element is an indicator light, the indicator o light operating by repeatedly flash illuminating for different durations, respectively, indicating the reversed power supply 5 and power return terminal connections, and the loss of an earth connection to the earth terminal. rgrr
3. An electrical connector as claimed in claim 1 or 2, wherein the indicator element is connected between the power return and earth terminals, and the fault indicator circuit further has a rectifying diode connected in series with the indicator element and a shunt capacitor connected across the indicator element.
4. An electrical connector as claimed in claim 3, wherein the fault indicator circuit further has a series impedence connected with the indicator element for regulating, with the shunt capacitor, the actuation duration of the indicator element. An electrical connector as claimed in claim 4, wherein /jthe series impedence is provided by at least one resistor U ~0t p a 0*0 C a. o 0 4 a 9 eta, 4 0 I i connected between the power return terminal and the indicator light for regulating, with the shunt capacitor, the actuation duration of the indicator element when indicating reversed power supply and power return terminal connections.
6. An electrical connector as claimed in claim 5, wherein the series impedence includes at least one further resistor connected between the power supply terminal and the indicator light, the resistors regulating, with the shunt capacitor, the actuation duration of the indicator element when indicating the loss of an earth connection to the earth terminal.
7. An electrical connector as claimed in any preceding claim, wherein the fault indicator circuit is also operable to indicate a presence of an electrical connection between the power supply and power return terminals and their respective 15 electrical conductors.
8. An electrical connector as claimed in claim 7, wherein the indicator means includes a voltage indicator circuit having at least one indicator light illuminating to provide a visual indication of the presence of the electrical connection. 20 9. An electrical connector as claimed in claim 8, wherein the~ indicator light providing the indication of the reliable electrical connection is connected between the power supply and power return terminals and the voltage indicator circuit further has a series impedence connected with the indicator 25 light.
10. An electrical connector as claimed in claim 9, wherein the series impedence is provided by at least one resistor.
11. An electrical connector as claimed in claim 9 or 10 when appended to any one of claims 3 to 6, wherein the voltage indicator circuit is connected in parallel with the fault indicator circuit.
12. An electrical connector as claimed in any preceding claim, wherein the connector is in the form of an electrical plug or socket.
13. An electrical connector, substantially as hereinbefore described with reference to the accompanying drawing. DATED: 24 December, 1991 PHILLIPS ORMONDE FITZPATRICK Attorneys for: TRIANGLE CABLES PTY. LTD. 0112E 11