AU733087B2

AU733087B2 - Improved electrical connector

Info

Publication number: AU733087B2
Application number: AU22562/99A
Authority: AU
Inventors: Michael Instance; Walter Riede; Ashok Sardesai; Case Schaafsma; Peter Sibary; Philip Timbrell; Michael Zantides
Original assignee: Utilux Pty Ltd
Current assignee: Tyco Electronics Pty Ltd
Priority date: 1998-03-05
Filing date: 1999-03-31
Publication date: 2001-05-03
Anticipated expiration: 2018-03-05
Also published as: AU701000B3; GB2337875A; CN1228630A; GB9905032D0; AU2256299A; GB2337875B

Description

I

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicant: UTILUX PTY LIMITED A.C.N. 003 070 148 Invention Title: IMPROVED ELECTRICAL CONNECTOR The following statement is a full description of this invention, including the best method of performing it known to me/us: Your Ref: Improved Insulated Plug-Pin

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2 IMPROVED ELECTRICAL CONNECTOR The present invention relates generally to an electrical connector, and particularly, but not exclusively, to a plug-pin connector, such as the type used in domestic electrical plugs. The invention also relates to a method of manufacturing an electrical connector.

Plug-pin connectors are well known. They commonly consist of a forwardly extending portion, in use extending from the face of a plug housing and comprising a substantially flat blade element or a cylindrical plug-pin element adapted for mechanical and electrical interengagement with a suitable receptacle plug-socket receptacle). They also comprise a rearwardly extending fortion, in use mounted within the plug and being arranged to be connected to an electrical conductor. The rearwardly extending portion usually comprises a part which is crimpable to an exposed conductive wire and also may comprise a further section or portion crimpable around the wire insulation. A plurality of such connectors (usually three) are employed in most domestic plugs. During manufacture, the plurality of plug-pins are mounted through S• slots or holes in a partition which is to form one face of the plug, being held in predetermined orientation with respect to each other in the partition. Wire conductors are inserted into the rearwardly extending portions, which are crimped thereto and then the wires and the rearwardly extending portions are potted in an insulating material.

Plugs manufactured in this way are safe because it is not possible for anybody to access and rewire the plug. An alternative procedure is to crimp the wires to the plugpins first, and subsequently insert the plug-pins into the partition and pot.

One problem with electrical connectors such as domestic plugs is that, in some circumstances, a plug may be slightly removed from a socket or tilted so that \\GHSYDNTI\users\Speci\300 399\300 349\33995.ioc 3 portions of the plug-pins are exposed while the ends of the forwardly extending portions are still in electrical contact with the socket. This is dangerous, as a small child can slip their fingers between the plug socket face and the plug face and touch the conductors, which are still live. Metal or otherwise conductive implements may also fall down in between the plug face and socket face and become live themselves, and lead to the possibility of accidental electrocution.

This problem has been addressed in some countries by the manufacture of plug-pins having a part of the forwardly extending portion insulated. The insulated part preferably extends along a sufficient length of the forwardly extending portion of the plug-pin that, if a plug mounting 15 the plug-pins is partially removed from a plug socket, the .i actual conductive part of the forwardly extending portion will not be exposed until it is no longer in electrical contact with the socket. Only the insulated part will be S"exposed while electrical contact is maintained. This S" 20 reduces the chances of accidental electric shock.

The applicant's own prior petty patent application *e*e*number AU40006/97 discloses an improved plug pin and method 0 of manufacturing an improved plug pin. The plug pin includes a first forwardly extending conductive element 25 including a first portion with first, larger, external dimensions, and a second portion having second external dimensions which are smaller than the first external dimensions. The second portion is covered with an insulating layer or member. This improved plug pin is manufactured, preferably, by folding a flat blank of material. The disclosure of patent application number AU40006/97 is incorporated herein by reference.

The plug pin of application 40006/97 is a development of the applicant's earlier granted Australian petty patent number 659988, which discloses an electrical connector \\GHSYDNT\users\Speci\300 399\300 349\33995.doc 4 including a forwardly extending blade element portion which is substantially hollow. The disclosure of petty patent number AU659988 is also incorporated herein by reference.

A further problem which needs to be addressed in the formation of electrical connectors such as plug pins, which have a section of a forwardly extending portion insulated, is how to conveniently fit the insulation to the portion which is to receive it. This portion will usually be of reduced dimensions relative to the rest of the forwardly extending portion of the electrical conductor. In the prior art, a number of approaches have been taken to mount the insulating material, and/all raise problems.

The present invention provides an electrical 1 connector, comprising a forwardly extending conductive element, the forwardly extending conductive element including a first portion having first external dimensions, and a second portion having second external dimensions which are smaller than the first external dimensions, the second portion being at least partly covered in an 20 insulating layer, the external dimensions of the combination of the second portion and the insulating layer or member being less than or substantially equivalent to the first external dimensions, the forwardly extending conductive element being formed by folding a conductive 25 blank which has been prepared to the appropriate dimensions for forming the first portion and second portion, wherein the insulating layer is formed by mounting a portion of insulating material to the area of the conductive blank which is to form the second portion after folding, and then proceeding to fold the conductive blank so that the insulating material is folded with the conductive blank to form the insulating layer for the second portion, wherein the insulating layer is formed by mounting a portion of insulating material to the area of the conductive blank which is to form the second portion after folding, and then \\GHSYDNTl\users\Speci\300 399\300 349\33995.doc proceeding to fold the conductive blank so that the insulating material is folded with the conductive blank to form the insulating layer for the second portion, and wherein the second portion is formed by folding over opposing portions of conductive material so that ends of the portions of the conductor material or sides of the conductive material proximate the ends, face each other and the insulating material being arranged such that a portion or portions of the insulating material become trapped between these ends or sides proximate these ends, to facilitate retention of the insulating layer on the second portion.

Mounting the insulating portion to the metal blank before folding the metal blank has the advantage that the insulating layer of the second portion is formed in the same step that the blank is folded. This obviates the need for a separate step for adding the insulating layer. In the prior art, this separate step is necessary to add a separate pre-formed insulating body, for example.

20 Preferably, the first portion is hollow, as this facilitates manufacture.

Preferably, the insulating layer or member is positioned on the forwardly extending portion so that when the first hollow portion is connected with an electrically 25 conductive socket, the insulated portion reduces the chances of accidental electrical shock to a person.

Preferably, the electrical connector is a plug-pin connector and the insulating layer or member is positioned so that when the connector is mounted in a plug housing, the insulating layer extends from the face of the plug housing part way up the forwardly extending portion of the connector.

The forwardly extending conductive element comprises a folded blank of conductive material. Preferably, to form the first portion, side parts of a blank are folded to form \\GHSYDNT1\users\speci\300 399\300 349\33995.doc 6 opposed blade walls which are preferably held apart by a spacer wall to provide reinforcement, in a similar manner to the connector described in applicants early Petty Patent No. 659988. The second portion is similarly preferably formed by folding over parts of conductive blank material.

The second portion in the preferred embodiment is also preferably hollow, but may not be. Where the second portion is hollow, the side parts of the blank which form the second portion are folded to form opposed blade walls which are held apart by a spacer wall to provide reinforcement, the second portion being of narrower dimensions than the first portion. Preferably, the portions of the insulating layer are trapped between 1 so opposing sides of the spacer wall of the second portion, in 15 order to assist in retaining the insulating layer on the second portion.

The insulating material is preferably adhered to the

S.

blank of material before folding by an adhesive such as a high temperature curing adhesive. This assists in 20 retaining the insulating layer on the second portion.

In a preferred embodiment, insulating material is U. mounted to a flat piece of conductive material before the material is cut/stamped to form the blanks for conductors.

The material is mounted to portions of raw material which 4**@UU 25 are to finally form the second portion of a conductor.

This facilitates ease of manufacture.

Preferably, the insulating material is polyester layer, aramid layer or similar material. The material preferably has high dielectric strength.

The insulating material may be adhered to the metal raw material by induction heating via the metal and a high temperature curing adhesive (as discussed above) The electrical connector preferably also comprises a rearwardly extending element including a portion which is crimpable to a conductive wire. Applicants earlier Petty \\GHSYDNT1\users\Speci\300 399\300 349\33995.doc 7 Patent No. 678541 discloses a form of crimp barrel receptacle which comprises a hollow cylindrical portion formed from a flat blank which is rolled to form a cylindrical or substantially cylindrical cross section, ends of the flat blank overlapping each other to form an overlap join. This arrangement particularly facilitates assembly and manufacture of plugs. The disclosure of applicants earlier Petty Patent No. 678541 is incorporated herein by reference.

The electrical connector of the present invention may have a rearwardly extending element in the form substantially as described in applicants earlier patent number 678541 An alternative rearwardly extending portion may be a standard open crimp portion, or any other type of 15 portion.

The first portion of the forwardly extending o S"conductive element of the electrical connector preferably has, as discussed above, opposed blade walls held apart by a spacer wall. One blade wall is preferably formed by two 20 parts of the conductive blank folded over towards each other along spaced fold lines, and the spacer wall is :formed by a folding over of opposite edges of the two parts so that the two parts of the one blade wall meet at'a seam and the edges of the parts extend across from the one wall to the opposite wall to maintain the opposing walls in spaced relationship. The spacer wall preferably extends lengthwise alongthe first portion of the forwardly extending element.

In a preferred embodiment, a further portion of the forwardly extending element of the connector is manufactured to the same dimensions as the first portion.

In such a case, the insulated portion preferably is positioned between the first portion and the further portion. The further portion is preferably of the appropriate dimensions to fit into the slot of a plug face \\GHSYDNT1\users\Speci\300 399\300 349\33995.ioc 8 or bridge to facilitate assembly and manufacture, and assist stability in the face of the plug. Most slots in plug faces are pre-manufactured to the appropriate dimensions for a standard plug-pin element.

The electrical connector need not include a forwardly extending element which is a substantially flat blade-element, as described in applicants earlier Petty Patents. A substantially rectangular plug-pin may be formed as a "box" structure by folding from a flat blank.

Similarly, a cylindrical plug-pin, such as the European-type pin, may be formed with at least one hollow portion formed from a flat blank and another portion of narrower dimension formed from the flat blank. The portion of narrower dimension may be formed to have opposing ends 15 or sides proximate the ends, for trapping insulating material between them to facilitate retaining the S"insulating material on the portion.

The present invention further provides a method of forming an electrical connector, the electrical connector 20 comprising a forwardly extending conductive element adapted for mechanical and electrical interengagement with a suitable receptacle, the method comprising the steps of preparing a flat blank of conductive material to the appropriate dimensions for forming the forwardly extending 25 element, folding the blank to form the forwardly extending *"*element having a first portion having first external dimensions and a second portion having second external dimensions which are smaller than the first external dimensions, and providing an insulating layer or member to at least partly cover the second portion, wherein the external dimensions of the combination of the second portion and the insulating layer or member are less than or substantially equivalent to the first external dimensions, and further comprising the step of mounting insulating material to a portion of the flat blank of conductive \\GHSYDNT1\users\Speci\300 399\300 349\33995.dcic 9 material which is to form the second portion, so that the insulating layer is formed as the flat blank is folded to form the second portion, and forming the blank such that the second portion is formed by folding over opposing portions of conductive material so ends of the portions of the conductive material, or sides of the conductive material proximate the ends, face each other, the insulating material being mounted such that during folding the portion or portions of the insulating material become trapped between these ends or sides proximate these ends to facilitate retention of the insulating layer on the second portion.

Preferably, the flat blank of conductive material is prepared from an amount of raw conductive material, and the 15 method preferably includes the step of mounting the insulating material to the raw material to cover areas of ooo S"the raw material which are eventually to form the second portion. The raw material can then be stamped and/or cut to form the blanks (usually a plurality of blanks will be formed on a former strip) and the blanks can then be folded with the insulating material already mounted.

'.*The forwardly extending portion is preferably a blade element for a plug-pin and the method includes the steps of folding at least the first portion to form opposed blade o 25 walls held apart by a spacer wall. The second portion is also preferably formed so that opposed blade walls are held apart by a spacer wall and the insulating material is trapped between the opposed blade walls.

The connector also preferably comprises a rearwardly extending element, which may comprise a barrel receptacle and the method involves forming a hollow cylindrical portion from a flat blank which is rolled to form a cylindrical or substantially cylindrical cross section, to form an overlap join. Alternatively, the rearwardly extending element may be an open crimp receptacle, or any \\GHSYDNT1\users\Speci\300 399\300 349\33995.doc 10 other type.

The present invention yet further provides a plug including an electrical connector in accordance with any one or all of the features discussed above.

Features and advantages of the present invention will become apparent from the following description of embodiments thereof, by way of example only, with reference to the accompanying drawings, in which; Figure 1 is a perspective view from above and one side of an electrical connector in accordance with an embodiment of the invention; Figure 2 is a plan view of the connector of figure 1; Figure 3 is a side view from one side of the connector of figure 1; 15 Figure 4 is an underneath view of the connector of figure 1; S"Figure 5 is a rear view of the connector of figure 1; Figure 6 is a front view of the connector of figure 1; Figure 7 is a section on line B-B of figure 2; 20 Figure 8 is a section on line A-A of figure 2; Figure 9 is a plan view of a flat blank for forming the electrical connector of figure 1; S- Figure 10 is a plan view of a plurality of the flat blanks of figure 9 shown attached to a former strip.

25 Referring to the drawings, an electrical connector in *"*accordance with an embodiment of the present invention is generally designated by reference numeral 1. The connector comprises a forwardly extending conductive element 2 which, in this embodiment, is a substantially flat blade element.

The blade element 2 includes a first portion 3 having first external width W and breadth B dimensions (figures 3 and 4) The blade element also comprises a second portion 4, having second external width dimensions W2 and breadth dimensions B2 (figure The second external dimensions \\GHSYDNT\users\Speci\300 399\300 349\33995.doc 11 are smaller than the first external dimensions (it will be appreciated that Figure 8 is merely a larger scale drawing than Figs 3 and 4) In operation, the second portion 4 is covered with an insulating layer 5. In this preferred embodiment the insulating layer is a polyester layer, aramid layer, or similar material.

This embodiment of the electrical connector also includes a rearwardly extending element 6. The rearwardly extending element 6 includes a crimp body 7 which is arranged to be crimped to a conductive connector, such as a wire.

In operation, the rearwardly extending element 6 is mounted within a plug housing (not shown, but would be 15 clearly understood and well known to a person skilled in the art). The rearwardly extending element 6 may be potted S"in the plug housing after the crimp body is crimped to the electrical conductor in the plug. The forwardly extending element 2 extends outwardly of the plug housing to contact with an appropriate socket for the supply of power to an appliance, for example. The face of the plug from which the portion 3 extends, in operation abuts against the insulating layer 5 or extends slightly over it.

In operation of the plug, the portion 3 makes electrical contact with the power socket. Should the plug *be pulled slightly outwardly away from the socket, the insulating layer 5 will ensure that no one can electrocute themselves. Preferably, the lengths of the portion 3 and portion 4 is such that when the plug is pulled out to an extent where the conductive portion 3 is exposed, the conductive portion 3 is no longer in electrical contact with the power supply socket.

The dimensions of the insulating layer 5 are such that when the insulating layer 5 is mounted about the second portion 2, external dimensions of the mounted insulating \\GHSYDNT\users\Speci\300 399\300 349\33995.doc 12 body 5 are less than or equal to the dimensions W and B of portion 3. The dimensions W and B are determined to comply with the standards required for the dimensions of pin plugs to fit into the appropriate sockets. When the plug-pin is complete, therefore, with the insulating layer 5, the forwardly extending portion 4 or at least the portion of it which is intended to extend into a socket receptacle will comply with all the dimensional requirements. As long as the outer dimensions of the insulating layer 5 do not exceed the dimensions W and B the insulating layer will not interfere with the fit into the receptacle.

The embodiment shown in the drawings is formed from an blank of conductive material. The blank is formed from a plate or strip of raw conductive material copper, 15 brass) by stamping/cutting to the appropriate shape and dimensions. The blank is then folded to form the final S00 plug-pin.

To ensure that the portion 3 is of the correct dimension B, it is formed as a hollow portion 3. Parts 8, 9 of the conductive blank are folded over towards each other to form a top blade wall 8, 9 and further parts and 11 are folded to form a spacer wall 10, (not shown) which spaces the top wall 8,9 away from the opposite bottom wall 12 of the portion 3. This construction is the same as *i 25 that used in the applicants earlier patent discussed above (Petty Patent No.659988).

The second portion is formed in a similar way, (as this is most clearly illustrated in Figure A top wall 31 is formed by folding over parts 30, 31 of the conductive blank and a spacer wall is formed by further parts 32 and 33, which operate to space the top wall 30, 31 away from the bottom wall 12. It can also be seen that sides 35, 36 of the spacer walls 32, 33, proximate the ends of the portions 32, 33, face each other. Portions 38, 39 of the insulating material are trapped between these sides \\GHSYDNT1\users\Speci\300 399\300 349\33995.doc 13 36 and this facilitates retention of the insulating layer 5 on the portion 4.

The rearwardly extending element is of the form disclosed in applicants earlier Petty Patent No. 678541.

The rearwardly extending element 6 is in this case formed as in Petty Patent No. 678541, from a flat blank rolled to the shape shown to provide a conical entry 21 to facilitate assembly.

Figure 9 shows a blank of material cut to the appropriate shape to form the pin of Figures 1 through 7 by folding and rolling. A person skilled in the art will appreciate how this pin is formed. Like reference numerals are used for portions of the blank which are used to form the elements with the same reference numerals in figures 1 15 through 7. Figure 10 shows a plurality of the flat blanks 1 attached to a former strip 23.

S"In accordance with the present invention, before S"folding the blank portion of insulating material 50 which is subsequently to form the insulating layer 5, insulating material is mounted to the portion of the blank which is to form portion 4. In Figure 9, the insulating material 50 is shown in outline so that that blank can be perceived underneath it. When the blank is folded, therefore, the insulating material 50 will be folded with it to form the layer 5. In addition, the portions 38, 39 of the insulating material will be trapped between the parts 36 of the spacer walls 32, 33 of the portion 4.

In a preferred process in accordance with an embodiment of the present invention, insulating material may be mounted to the raw conductive material before the blanks are formed by stamping/cutting. Preferably the insulating material is a polyester or aramid layer which is preferably adhered to the conductive material by using a low temperature curing adhesive. The adhesive can be heated by induction heating through the conductive \\GHSYDNT1\users\Speci\300 399\300 349\33995.doc 14 material. In a preferred embodiment, the raw conductive material is stamped to form a step which is to divide the first portion and the second portion of reduced dimensions.

The insulating material is preferably applied before this stamping process and will facilitate the formation of the step.

The portion 40 of the connector, closest to the rearwardly extending element, is of the same dimensions W and B as the first portion 3. Having this further portion the same width as the first portion 3 facilitates assembly into a plug bridge or face. A plug bridge or face has a slot for receiving each forwardly extending blade element.

This slot is usually dimensioned to receive a standard connector. The portion closest to the rearwardly extending 15 portion will usually seat in this slot and therefore it is °of advantage if it is of the same dimensions W and B as the °oo standard connector (and the first portion). Preferably then, this further portion 40 is formed in a similar manner to the first portion 3, having the same dimensions W and B as the first portion. Preferably, it also has a spacer wall spacing opposed blade walls, as with the first portion 3.

The electrical connector of the present invention need not have a flat, blade like forwardly extending portion.

Other types of plug connector, cylindrical, could be manufactured in a similar way. That is, a forwardly extending portion could be manufactured by folding to provide a broader portion and the second portion could be formed by folding over parts of a flat blank to meet each other to form a portion of the appropriate thickness. With a cylindrical pin, this could be achieved by rolling the flat blank to meet at a seam where portions of the insulating material would be trapped between acts of the seam.

The hollow portion 3 of the connector may be filled \\GHSYDNT1\users\Speci\300 399\300 349\33995.doc 15 with material, if required, to provide support. Generally it is preferred that it remain hollow, with the spacer wall providing the required reinforcement.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

.o e \\GHSYDNT1\users\Speci\300 399\300 349\33995.doc

Claims

1. An electrical connector, comprising a forwardly extending conductive element, the forwardly extending conductive element including a first portion having first external dimensions, and a second portion having second external dimensions which are smaller than the first external dimensions, the second portion being at least partly covered in an insulating layer, the external dimensions of the combination of the second portion and the insulating layer or member being less than or substantially equivalent to the first external dimensions, the forwardly extending conductive element being formed by folding a conductive blank which has been prepared to the appropriate dimensions for forming the first portion and second 15 portion, wherein the insulating layer is formed by mounting S• a portion of insulating material to the area of the C. C S"conductive blank which is to form the second portion after S"folding, and then proceeding to fold the conductive blank so that the insulating material is folded with the 20 conductive blank to form the insulating layer for the second portion, and wherein the second portion is formed by folding over opposing portions of conductive material so that ends of the portions of the conductor material or sides of the conductive material proximate the ends, face 25 each other and the insulating material being arranged such *ooCoC that a portion or portions of the insulating material become trapped between these ends or sides proximate these ends, to facilitate retention of the insulating layer on the second portion.

2. An electrical connector in accordance with claim 1, wherein to form the first and second portions of the forwardly extending conductive element the side parts of a blank are folded to form opposed blade walls which are held apart by a spacer wall to provide reinforcement, the spacer wall extending substantially the length of the forwardly J:\Speci\300 399\300 349\33995.ioc 17 extending conductive element.

3. An electrical connector in accordance with claim 1 or claim 2, wherein the insulating material is adhered to the blank of material before folding by a high temperature curing adhesive.

4. An electrical connector in accordance with any one of claims i, 2 or 3, wherein the electrical connector is a plug pin connector. A method of forming an electrical connector, the electrical connector comprising a forwardly extending conductive element adapted for mechanical and electrical interengagement with a suitable receptacle, the method comprising the steps of preparing a flat blank of conductive material to the appropriate dimensions for 15 forming the forwardly extending element, folding the blank to form the forwardly extending element having a first •o portion having first external dimensions and a second S"0 portion having second external dimensions which are smaller *than the first external dimensions, and providing an S 20 insulating layer or member to at least partly cover the second portion, wherein the external dimensions of the *.combination of the second portion and the insulating layer *or member are less than or substantially equivalent to the first external dimensions, and further comprising the step 25 of mounting insulating material to a portion of the flat 0 blank of conductive material which is to form the second portion, so that the insulating layer is formed as the flat blank is folded to form the second portion, and forming the blank such that the second portion is formed by folding over opposing portions of conductive material so ends of the portions of the conductive material, or sides of the conductive material proximate the ends, face each other, the insulating material being mounted such that during folding the portion or portions of the insulating material become trapped between these ends or sides proximate these \\GHSYDNT\users\Speci\300 399\300 349\33995.doc 18 ends to facilitate retention of the insulating layer on the second portion. Dated this 31st day of March, 1999 UTILUX PTY LIMITED By their Patent Attorney Griffith Hack 0 o \\GHSYDNT1 \users \Speci \300 399\300 349\33995.doc