AU736023B2

AU736023B2 - Electrical connector

Info

Publication number: AU736023B2
Application number: AU84198/98A
Authority: AU
Inventors: Brian Baber; Michael Instance; Case Schaafsma; Phillip Timbrell; Michael Zantides
Original assignee: Utilux Pty Ltd
Current assignee: Tyco Electronics Pty Ltd
Priority date: 1997-10-09
Filing date: 1998-09-11
Publication date: 2001-07-26
Anticipated expiration: 2017-10-09
Also published as: AU692746B3; AR023009A1; NZ332230A; AU8419898A; CN1228629A

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicant: UTILUX PTY LIMITED A.C.N. 003 070 148 Invention Title: ELECTRICAL CONNECTOR a.

a *daa a a a The following statement is a full description of this invention, including the best method of performing it known to me/us: 2 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 Sinterengagement with a suitable receptacle plug-socket receptacle) They also comprise a rearwardly extending portion, in use mounted within the plug and being 15 arranged to be connected to an electrical conductor. The .0 rearwardly extending portion usually comprises a part which is crimpable to an exposed conductive wire and also may 0 *0 acomprise 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 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.

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 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 H:\USERS\SPEC\32272.doc 3 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 the plug-pins is partially removed from a plug socket, the 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 15 exposed while electrical contact is maintained. This reduces the chances of accidental electric shock.

A problem with presently available insulated plug-pins S* is that they are expensive to manufacture. There are two well-known types of insulated plug-pin. One is the type commonly used in the UK (the "UK type"), the forwardly extending portion of which includes a substantially solid rectilinear piece of metal A part of the forwardly extending portion is specially milled to receive an insulating covering, which is usually injection moulded.

The milling is necessary because there are strict requirements for the dimensions of plug-pins so that they will fit with the appropriate plug socket. Strict tolerance dimensions are laid down in various standards.

The forwardly extending portion of the plug-pin must therefore be specially milled to a reduced dimension, to allow the room for the insulation to be added without the addition of the insulation increasing the dimensions of the pin beyond that required by the standards.

Another type of insulated plug-pin which is presently available is the type commonly used in European countries such as Germany and France (the "European" type), where the H: \USERS\SPEC\32272.doc 4 forwardly extending portion of the plug-pin comprises a substantially solid rolled and milled cylindrical body.

Again, milling is required to reduce the dimensions of a part of the plug-pin to receive an insulating covering, so that the final dimensions of the pin comply with the appropriate standards. Again, such plug-pins are expensive to manufacture, and wasteful in materials.

The present applicants earlier granted Australian Petty Patent No. 659988 discloses an electrical connector, such as a plug-pin connector, which includes a forwardly extending blade element portion which is substantially hollow. The special construction of the hollow plug-pin results in manufacturing cost savings. The disclosure of Petty Patent No. 659988 is incorporated herein by 15 reference.

The forwardly extending blade element of the earlier Petty Patent is formed by folding a blank of conductive material to form opposed blade walls which are held apart by a spacer wall. It is therefore possible to maintain the overall dimensions required by the appropriate standards, while making a large saving on materials, because the blade element is hollow and therefore not as much material is used. Providing a spacer wall maintains the rigidity and strength of the blade element. This technique is particularly suited for making the connectors having the flat blade elements commonly used in Australasia and parts of Asia, but is not limited thereto.

The present invention provides 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 forming the forwardly extending element, folding the blank to form the forwardly extending element having a first portion having first external dimensions and \tSERS\SPEC\32272 .doc 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 wherein the step of preparing the flat blank includes the step of cutting out conductive material from each side of the flat blank to form recesses extending substantially the length of the second portion, whereby the second portion of reduced length may subsequently be formed by folding the portion with the recesses.

Preferably, the first portion is hollow.

15 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 conductive socket, the insulated portion reduces the S. 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 the blank are folded to form 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.

Preferably, the dimensions of the conductive blank are such that flaps are folded over to form the second portion so that opposed blade walls of the second portion meet each H:\USERS\SPEC\32272.doc 6 other to form the second portion of reduced dimensions.

The second portion is therefore, preferably, not hollow.

The insulating portion may be injection moulded or formed from insulating tape or by any other means, so that the outer dimensions of the insulating layer do not exceed the outer dimensions of the pin.

The electrical connector is also preferably formed comprising a rearwardly extending element including a portion which is crimpable to a conductive wire.

Applicants earlier Petty 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 S 15 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 formed by the method of the present invention may have a rearwardly extending element "in the form substantially as described in applicants earlier patent number 678541.

The first portion of the forwardly extending conductive element of the electrical connector is preferably formed with as discussed above, opposed blade walls held apart by a spacer wall. One blade wall is preferably formed by two 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 along the first portion of the forwardly extending element.

H:\USERS\SPEC\32272.doc -7- An advantage of the electrical connector formed in accordance with the method of the present invention, is that it is formed from a folded conductive blank. Blanking operations can therefore be performed to cut the original conductive blank to the required dimensions before folding.

No expensive milling operations are required. Such an electrical connector can therefore be manufactured as an insulated plug-pin, preferably at a much cheaper price than presently available insulated plug-pins.

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 15 portion. The further portion is preferably of the *..appropriate dimensions to fit into the slot of a plug face 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. The element may be substantially rectangular, in a similar way to the UK plug-pin. A substantially rectangular plug-pin may be formed as a "box" structure by folding from a flat blank.

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 1A is a perspective view from above and one side of an electrical connector formed in accordance with an embodiment of the invention, without insulation; Figure lB is a perspective view from above and one side of the connector of figure 1A, with insulation; H:\USERS\SPEC\32272.doc 8 Figures 2A and 2B are perspective views from above and the rear of the connector of figure 1A, without and with insulation, respectively; Figure 3 is a plan view of the connector of figure 1A; Figure 4 is a side view of the connector of figure 1A; Figure 5 is a section on line B-B of figure 4; Figure 6 is a section on line A-A of figure 4; Figure 7A is a perspective view from above behind of an alternative connector formed in accordance with an embodiment of the present invention, with insulation; Figure 7B is a perspective view from above and behind of the connector of figure 7A, without insulation; Figure 8A is a plan view of a flat blank from which .e the connector of figures 7A and 7B may be formed; 0 0 .s 15 Figure 8B is a plan view of a plurality of the blanks .o of figure 8A shown attached to a former strip; Figure 9A is a plan view of a flat blank for forming a further embodiment of an electrical connector in accordance with the present invention; Figure 9B is a plan view of a plurality of the flat "blanks of figure 9A shown attached to a former strip; 0 Figure 10 is a perspective view from above and one side of a plug face or bridge with electrical connectors eeee• formed in accordance with the connectors of figures 9A and 9B inserted therein; Figure 11 is a front view of the plug bridge of figure Figure 12 is a side view of the plug bridge of figure and Figure 13 is a rear view of the plug bridge of figure Referring to the drawings, an electrical connector formed 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 H:\USERS\SPEC\32272.doc 9 flat blade element. The blade element 2 includes a first portion 3 having first external width W and breadth B dimensions (figure 1A) The blade element also comprises a second portion 4, having second external width dimensions W2 and breadth dimensions B2 (figure 1A). The second external dimensions are smaller than the first external dimensions.

In operation, the second portion 4 is at least partly covered with an insulating layer or member 5 (figure lB and figure 2B). The layer or member 5 may be an injection moulded layer of plastics insulating material or may be a plastics sleeve or tape.

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 clearly understood and well known to a person skilled in the art). The rearwardly extending element 6 is potted 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 body 5 or extends slightly over it. This is similar to the case with the UK or European type plug-pins discussed above.

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 body 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 H:\USERS\SPEC\32272.doc 10 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 body 5 are such that when the insulating body 5 is mounted about the second portion 2, external dimensions of the mounted insulating 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 added insulating body 5, the forwardly extending portion 4 or at least the portion of it which is intended to extend into a socket receptacle will o comply with all the dimensional requirements. As long as 0*0.0 the outer dimensions of the insulating body 5 do not exceed 0,0*0 the dimensions W and B the insulating body will not interfere with the fit into the receptacle.

The embodiment shown in the drawings is formed from an original flat blank of conductive material. The flat blank 20 is formed from a plate of conductive material SSe coppers, brass) by blanking to the appropriate shape and gee• dimensions. The blank is then folded to form the final plug-pin.

The conductive material is of one thickness, being approximately a third the required dimension B. To ensure that the portion 3 is of the correct dimension B, it is formed as a hollow portion 3 as most clearly illustrated in figure 5. Parts 8, 9 of the conductive blank are folded over towards each other to form a top blade wall 8, 9 and further parts 10 and 11 are folded to form a spacer wall 11 which spaces the top wall 8,9 away from the opposite bottom wall 12 of the portion 3. This construction is the same as that used in the applicants earlier patent discussed above (Petty Patent No.659988). In this connector however, it is only this first portion 3 of the plug-pin which is constructed in this way and not the H:\USERS\SPEC\32272.doc 11 entire forwardly extending portion 2.

The portion 4 is constructed in a different manner.

It is made from material of the same thickness (the same blank), but the material of this portion is stamped to such dimensions that parts 14 and 15 can be folded directly over to meet each other at a seam 16 to form a top blade wall 14,15 which directly abuts bottom blade wall 17 of portion 2. The total thickness of the portion 2 is therefore B2 and the width is dimensioned to be W2, (see figure 6) Subsequently, an insulating layer or body 5 is added.

The rearwardly extending element may not be of the form shown in the above embodiment but could be of any other form. In one preferred embodiment, it is of the form disclosed in applicants earlier Petty Patent No. 678541, as 15 shown in figures 7A and 7B. This facilitates assembly and connection of conductors during manufacture of plugs.

In figures 7A and 7B the same reference numeral as used in the previous figures are used for like parts of the o connector. The rearwardly extending element 20 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 8A shows a flat blank of material cut to the appropriate shape to form the pin of 7A and 7B 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 figure 7A and 7B. Figure 8B shows a plurality of the flat blanks 1 attached to a former strip 23.

In the previous embodiments, the portion of the forwardly extending element 2 which is closest to the rearwardly extending portion is shown as being of the same dimensions as the portion arranged to receive the insulating member or layer 5. Preferably, this portion, closest to the rearwardly extending element, is of the same H:\USERS\SPEC\32272.doc 12 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 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 standard connector (and the first portion). Preferably then, this further portion (illustrated by letter A in figure 7A) 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.

Figures 9A and 9B show a flat blank for forming an electrical plug-pin connector which has a further portion 25 which is to be formed as the same dimension W and B as the first portion 3. Other features are the same as blanks figure 8A and 8B. The difference is that the part A is of increased dimensions.

~Figures 10 through 13 show a plug bridge or face which is of standard form for receiving connectors ,.ee.ei manufactured from the blank of figure 9A and 9B.

Connectors are shown as 31, 32 and 33 respectively.

Following insertion of the connectors into the plug wall conductors will be inserted into the rearwardly extending elements 20 and they will be crimped thereto.

The plug housing will then be potted and completed. The techniques applied are known to those skilled in the art.

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

Other types of plug connector, e.g. the thicker UK type 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 H:\USERS\SPEC\32272 .doc 13 could be formed by folding over parts of a flat blank to meet each other to form a portion of the appropriate thickness.

The hollow portion 3 of the connector may be filled 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.

55b5** H:\USERS\SPEC\32272.doc

Claims

1. 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 forming the forwardly extending 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 wherein the step of ".*".preparing the flat blank includes the step of cutting out conductive material from each side of the flat blank to "form recesses extending substantially the length of the second portion, whereby the second portion of reduced length may subsequently be formed by folding the portion eee f with the recesses.

2. A method of forming an electrical connector in accordance with claim 1, wherein the step of forming the recesses includes the step of radiussing the ends of the recesses in order to maintain the strength of the pin when the metal is folded. H:\USERS\SPEC\32272.doc 15

3. A method in accordance with claim 1 or claim 2, the step of folding the blank to form the first portion having first external dimensions, including the step of folding portions to provide opposing walls and a spacer wall bridging the opposing walls. Dated this llth day of September 1998 Utilux Pty Limited By their Patent Attorneys GRIFFITH HACK o* *0 6* s* 0 0 0 *09 H:\USERS\SPEC\32272.doc