AU713232B3 - Improved electrical connector - Google Patents

Description

AUSTRALIA

PATENTS ACT 1990

ORIGINAL

COMPLETE

SPECIFICATION

PETTY PATENT Invention Title: IMPROVED ELECTRICAL

CONNECTOR

Name of Applicant: UTILUX PTY LIMITED The following statement is a full description of this invention, including the best method of performing it known to me/us: 2 IMPROVED ELECTRICAL CONNECTORS The present invention relates generally to electrical connectors, and particularly, but not exclusively, to plug pin connectors, such as the type used in domestic electrical plugs. The invention also relates to a method of manufacturing electrical connectors.

Plug pin connectors are well known. They commonly consist of a forward portion, in use extending from the face ("pin holding partition") of a plug housing and comprising a substantially flat blade element, a rectangular, square or cylindrical pin element adapted for mechanical and electrical interengagement with a suitable receptacle (plug-socket receptacle). They also comprise a rearwardly extending portion, in use mounted within the plug and being arranged to be connected to an electrical conductor. The rearwardly extending portion usually comprises a section which is crimpable to an exposed 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 pins are mounted through slots or holes in the pin holding partition, being held in a predetermined orientation with respect to each other in the partition, the 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.

It is desirable that the manufacturing process for plugs be automated as much as possible in order to keep labour costs low. It is also desirable that material costs be minimised and that the number of steps in the manufacturing process be minimised, again in order to keep costs to as low a level as possible.

.T\;np \300 149\32752.doc 3 To this end, automated manufacturing processes are applied in which, after the plug pins have been inserted through the partition, conductive wires are automatically inserted into the rearwardly extending connector portions and a crimping machine automatically crimps the rearwardly extending portions to the wires, ready for the subsequent potting step.

There are a number of forms of rearwardly extending connector portions available. One well-known form is the "bucket" crimp receptacle. This comprises a generally "U" cross section bucket, having an open top. The conductor is dropped into the bucket and the crimping tool used to crimp the bucket to the conductor. This form of crimp receptacle is perhaps the simplest in which to automatically by machine) insert a conductor, as the conductor can easily be dropped or inserted into the top of the bucket.

One of the most popular and most cost effective to manufacture forwardly extending elements of a plug pin connector is a flat blade element. A substantially flat blade element can be manufactured by folding a blank of conductive material. A problem arises with the use of a flat blade element (and other non-circular plug pin elements, such as those having a rectangular or square cross-section)in relation to the automated manufacture of plugs. Generally, the orientation of the flat blade connector when it is placed into the plug partition may vary depending upon whether the plug pin is to form the active, neutral or earth pin of the plug. In Australia, for example the top-most (earth) blade pin in a plug is vertically orientated (that is the width of the blade lies in a vertical direction in use), whereas the blades of the active and neutral pins are inclined at opposing angles.

Plug pins having forwardly extending flat blade elements (and other non-circular forwardly extending plug pin elements) and rearwardly extending bucket crimp J:\Speci\300 399\300 349\32752.doc 4 receptacles are always formed with the bucket crimp receptacle in a fixed orientation with respect to the flat blade-element. The open top of the bucket is formed in the same plane as the plane of the flat blade element (i.e.

same orientation as the flat blade element).

In a plug such as described above, therefore, the rearwardly extending receptacle, if it is a bucket crimp receptacle, will also be orientated so that the buckets for each connector are disposed in different orientations.

This complicates the automated manufacturing process, as, firstly, the conductors for each of the plug pins must be dropped into buckets which are orientated so that their open tops face in different directions and, secondly, a crimp tool must be orientated differently to crimp each of the crimp receptacles. This difference in orientation of the crimp receptacles causes so many problems with the automated process that, as far as the applicants are aware, an automated process for assembly of plugs utilising pins having bucket crimp receptacles has not been applied.

An alternative form of crimp receptacle is the "barrel" crimp receptacle. In plug pins employing such a crimp receptacle the rearwardly extending portion comprises a hollow cylindrical barrel which is arranged to receive the conductor conductive wire) through the open end of the barrel. There are also problems involved in automated assembly of a plug using pins employing barrel receptacles. The applicants petty patent number 678541 discloses an electrical connector utilising a barrel crimp receptacle which addresses these problems.

Nevertheless, use of a barrel receptacle in automated plug assembly is not ideal. There are difficulties involved in inserting the wire conductor through the open end of the barrel. The wire conductor may miss, for example. In order to address this problem barrel receptacles have been manufactured with flared entries to the open end. This increases complexity of the manufacturing process and also still does not provide a satisfactory solution to the problem of wire insertion through the open end of the barrel receptacle.

A further problem with barrel receptacles is that in order to manufacture them a significant amount of substrate conductive material is required as compared with that required for formation of a bucket crimp. Barrel crimp receptacles are therefore expensive in materials.

It would be desirable to be able to use bucket crimp receptacles in an automated manufacturing process, as it is easier to drop the wire conductor into a bucket receptacle than it is to insert through the open end of a barrel receptacle.

The present invention provides a plurality of plug pin connectors for the automated manufacture of a plug, each of the plug pin connectors comprising a forwardly extending blade element and a rearwardly extending bucket crimp receptacle, it being required that the forwardly extending blade element of each of the plurality of plug pin connectors lie at different angular orientations to each other within a plug partition, the bucket crimp receptacle being arranged to receive an electrical conductor therein to be crimped thereto, bucket crimp receptacles of each of the plurality of plug pins being oriented relative to their J:\Speci\300 399\300 349\32752.doc -6respective forwardly extending non-circular plug pin elements, such that when the forwardly extending noncircular plug pin elements are mounted within the plug partition, then the bucket crimp receptacles are all oriented in the same direction, or one or more are oriented in one direction and the other or others are oriented in the opposite direction.

Preferably the orientation of the crimp receptacle of each plug pin is "twisted" with respect to the longitudinal axis of the connector so that its top face inclines at an angle to the transverse symmetrical plane through the connector.

Preferably, the bucket crimp receptacle is formed so that a plane extending across the open top of the bucket crimp receptacle extends at an angle greater than 00 to the transverse plane of symmetry of the non-circular plug pin element. The plane extending across the open top of the bucket crimp is preferably not inclined at an angle to the longitudinal axis of the forwardly extending non-circular plug pin element.

Preferably the angle is greater than 100.

Preferably, the forwardly extending non-circular plug pin element is a flat blade element, or an element having a rectangular cross-section. It may have an oval cross- 2 section, or any other cross-section, except circular.

K:\Speci\300 399\300 349\32752.doc 7 Please note that by "bucket crimp" we mean any crimp receptacle which provides an open top part by which a conductor may be dropped into the "bucket" Plug pin elements in accordance with the present invention can advantageously be used in the automated assembly and manufacture of plugs. Because the crimp bucket receptacle is oriented at an angle to the forwardly extending element, the angle of orientation can be chosen so that it is convenient for a machine tool to insert the wire into the open top of the bucket and for a crimp tool to automatically crimp the bucket. Where it is required that a plug have flat blade (or other non-circular elements)elements which are orientated at different angles to each other, in a preferred embodiment of the invention, connectors are provided where the rearwardly extending bucket crimp for each connector is oriented with respect to the flat blade element at an appropriate angle so that when the blade is inserted into the plug partition, the bucket crimps of the pins in the plug bridge are all oriented in the same direction. All the conductors can therefore be inserted into the buckets of the pins from the same direction. Further, a single crimp tool oriented in one direction can be used and the orientation need not be altered for each pin. In this embodiment a plurality of plug pin connectors are provided for a plug assembly, each J:\Speci\300 399\300 349\32752.doc 8 connector having its bucket crimp oriented at a different angle to the respective forwardly extending to the element, from the bucket crimp of the other plug pin connectors.

In an alternative embodiment, the bucket crimps need not all be of oriented in the same direction. One or more of the bucket crimps may be oriented so the open face of the bucket faces in the opposite direction to the other or others of the bucket crimps in the plug partition. In this case the only extra operation that would be necessary during crimping would be to turn the plug partition over once, in order to provide for a separate crimping operation for the bucket or buckets the open tops of which face in the opposite direction. In some processes it may be desirable to do this e.g. to crimp the live and neutral conductors in a first operation and to crimp the (opposite facing bucket crimp) earth conductor in a separate operation.

Preferably, the plug pin connectors of the present invention are formed so that there is a relatively narrow neck portion connecting the rearwardly extending bucket crimp to the forwardly extending plug pin element. The bucket crimp can preferably be bent about this neck portion to extend in the desired orientation. A fold along which the bend is made preferably extends lengthwise in the same direction as the lengthwise extension of the forwardly J:\Speci\300 399\300 349\32752.doc 9 extending plug pin element.

Features and advantages of the present invention will become apparent from the following description of an embodiment thereof, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a perspective view from above of an electrical connector in accordance with an embodiment of the present invention; Figure 2 is a perspective view from above of an electrical connector in accordance with a further embodiment of the present invention; Figure 3 is a perspective view from above of an electrical connector in accordance with a further embodiment of the present invention; Figure 3B is a schematic cross-sectional view of the J:\Speci\300 399\300 349\32752.doc 10 forwardly extending element of the connector of Figure 3.

Figures 4 through 9 are perspective views from behind and one side of electrical connectors in accordance with embodiments of the present invention; Figure 10 is a perspective view from above and behind of a plug-bridge assembly incorporating electrical connectors in accordance with embodiments of the present invention; Figures 11 through 16 are side, bottom, other side, top, front end and rear end views, respectively, of an electrical connector in accordance with an embodiment of the present invention; Figure 17 is a view from the top of a plurality of electrical connectors in accordance with the embodiment of figures 11 through 16 shown mounted to a former strip; Figures 18 through 23 show a side, bottom, other side, top, front end and back end views irrespectively of an electrical connector in accordance with a further embodiment of the invention; Figure 24 is a view from above of electrical connectors in accordance with the embodiment of figures 18 through figure 23 shown attached to a former strip; Figures 25 through 30 show side, bottom, other side, top, front end and back end views irrespectively of an electrical connector in accordance with a further embodiment of the present invention; Figure 31 shows a plurality of electrical connectors of the embodiment of figures 25 through 30 shown attached to a former strip; Figure 32 through 37 show side, bottom, other side, top, front end and back end views, respectively, of an electrical connector in accordance with a further embodiment of the present invention; Figure 38 shows a plurality of electrical connectors of the embodiment of figures 32 through 37 shown attached 11 to a former strip; Figures 39 through 41 are drawings illustrating stages in the process of manufacture of an electrical connector in accordance with an embodiment of the present invention; Figures 42 through 44 are drawings illustrating stages in the process of manufacture of an electrical connector in accordance with a further embodiment of the present invention, and Figures 45 through 47 are drawings illustrating stages in a process of manufacture of an electrical connector in accordance with a further embodiment of the present invention.

The following description will be given in relation to an embodiment of an electrical connector of the type which has a forwardly extending substantial flat blade element.

As discussed above, however, the invention may be applied to connectors having other types of forwardly extending plug pin elements (non-circular), such as, for example, rectangular element or square element. The following description of the connector with a forwardly extending flat blade element is given as an example embodiment only.

Referring, firstly, to figures 1 to 3, electrical connectors in accordance with embodiments of the present invention are illustrated. These electrical connectors are plug pins and they have a number of features in common. In order to distinguish them in this description, each electrical connector has been given a separate reference numeral, 1, 2 and 3 respectively. Otherwise, similar reference numerals are used for similar features of each of the connectors 1, 2 and 3.

Each connector 1, 2, 3 comprises a forwardly extending blade element 4. The forwardly extending blade element is arranged for mechanical and electrical engagement with a corresponding socket, such as a domestic plug socket. The blade element 4 is also provided with an insulating body or 12 layer 5 for the prevention of accidental electric shock.

The blade element is also provided with a springy tang on the underside (not shown in figures 1 to 3 but shown, reference numeral 10 in the embodiments of figures 4 through 6) and also a flange 11 at the base of the blade element 4. The flange 11 and springy tang 10-affect an interference fit with a plug partition within which the blade element 4 is inserted during manufacture of a plug assembly, maintaining the connector i, 2, 3 mounted in the plug partition (see later).

The forwardly extending blade element 4 may be manufactured in a conventional fashion from a flat blank of conductive material folded to form the blade element 4.

Reference should be had to the applicants earlier patent applications and patents for various methods of forming flat blade connectors, for example petty patent application number AU57394/98, petty patent application number AU40006/97 and petty patent number AU659988. For the purposes of the present invention, however, the form and method of manufacture of the forwardly extending blade element 4 is irrelevant. It may be any conventional blade element and may be manufactured in any conventional way.

Electrical connector i, 2, 3 also comprises a rearwardly extending bucket crimp receptacle 6. The bucket crimp receptacle is arranged to receive a conductor a wire conductor) such as a wire conductor through an open top 7 and then to be crimped to the conductor in a known manner, by a crimping tool, in order to make conductive and mechanical contact with the conductor.

In the illustrated embodiment, for each connector i, 2, 3, the crimp bucket 6 is attached to the flat blade element by an interconnecting neck portion 8. The neck portion is formed by appropriate stamping of the original flat blank of conductive material. This is different from conventional plug pins which mount bucket crimps. In J:\Soeci\300 399\300 149\32792.dor 13 these, the connection to the forwardly extending plug pin is by a relatively rigid usually straight portion.

The neck portion 8 of the connector i, 2, 3 can be folded along a fold portion 9 to change the orientation of the crimp bucket 6 with respect to the blade element 4.

In the connector i, the neck portion 8 has not been folded and the crimp bucket 6 sits in its conventional orientation with respect to the blade element 4. In the electrical connectors 2, and 3, the neck portion 8 has been folded so that the crimp bucket 6 in each case is at an angle to the blade element 4, so that the open top 7 of the crimp buckets also extends at an angle to the plane of the flat blade element 4. During manufacture, the neck 8 can be folded along fold line 9 to provide any desired angle of orientation of the crimp bucket 6 with respect to the blade element 4.

Figure 3b shows a schematic cross-section through a flat blade element such as the flat blade element 4 of Figure 3(reference numeral 100). The line YY indicates what we mean by the transvers symmetrical planes of the flat blade element. It is a plane which extends along the flat blade element, either side 101 and 102 of which is symmetrical. Referring again to Figure 3, the line XX indicates the plane in which the open top face 7 of the bucket crimp 6 is oriented in. In the present invention, (as indicated by line XX) of the bucket crimp is "twisted" with respect to the longitudinal axis 00 of the pin so that the top face (XX) is inclined at an angle to the transverse symmetrical plane YY, as is clearly indicated in Figure 3B.

Note that when we refer to the transverse symmetrical plane we are referring to the plane which lies within the larger width dimension of the extending plug pin element and not the smaller width dimension. With a square pin, this distinction is irrelevant.

Figures 4, 5 and 6 show further embodiments of the 14 connector in accordance with the present invention, being connectors 20, 21 and 22. The same reference numerals are used for the same features as illustrated in figures 1 to 3.

The connector 21 is intended for use as an earth pin for a domestic plug. The connector 20 is intended for use as an active and the connector 22 as a neutral.

In many domestic (and non-domestic) electrical plugs, the orientations of each of the plug pins when mounted within the plug are required to be different either because of regulatory standards or merely to comply with the standard way in which plugs are manufactured. Figures 4, and 6 show the standard orientations for a domestic plug for use in Australia. The flat blade 4 of the earth plug pin 21 is orientated vertically in use (the plane of the flat blade element 4 lies in the vertical direction) and the active 20 and neutral 22 are inclined at opposing angles. As discussed in the preamble, this creates problems with automated assembly of the plugs, particularly insertion of the wire conductors into the crimp receptacle 6 and subsequent crimping of the receptacles to the conductors.

In accordance with the present invention, however, forming the bucket crimp 6 and folding the neck portion 8 enables each of the crimp buckets 6, in use, to be oriented in the same direction, as shown in figures 4 through 6.

This facilitates assembly of the wire conductors to the buckets 6 and crimping of the buckets 6. In each case, the buckets 6 of the connectors 20, 21 and 22 are oriented differently from each other with respect to their connected blade elements 4. The result when the connectors are inserted into a plug bridge, however, is that the orientations of the crimp bucket 6 are the same. Figures 7, 8 and 9 illustrate a further set of plug pin connectors and similar reference numerals are used for the same 0

I

15 components as in previous embodiments. Again, as with the connectors of figures 4, 5 and 6 the connectors (active), 26 (neutral) and 27 (earth) are orientated in the same way as they would be orientated in use in a plug bridge. The respective bucket crimp receptacles 6, however, are arranged so that they are orientated in the same direction.

Note that in the embodiments of figures 4 through 9, the earth pin connectors 21 and 27 do not require an insulating layer Figure 10 illustrates the electrical conductors of figure 7, 8, 9 in situ in a plug partition 30. The plug partition 30 is of conventional form for an Australian-type domestic plug. It includes a plastics insulating base 31 which has 3 slots through it (which cannot be clearly seen but which are generally indicated by reference numerals 33, 34 and 35). The orientation of the slots governs the orientation of the blade elements 4 of the plug pins 25, 26 and 27, and the orientations are as shown, with the earth pin 27, being substantially vertical in use and the active and neutral 26 pins being inclined at opposed angles.

It can be clearly seen that because of the adjusted orientations of the pins 25, 26 and 27, crimp buckets 6 all face in the same direction. This facilitates fastening of the respective conductors for the crimp bucket 6, as discussed above. In an alternative embodiment (not shown) one of the crimp bucket 6 could be oriented in an opposite direction to the others of.the crimp buckets. For example, if the earth pin 27 were reversed in its orientation in the slot 34, then the crimp bucket 6 of the earth pin 27 would face in the opposite direction to that of the crimp buckets of the pins 25 and 26. This may require a further crimping operation but in some circumstances this may be desirable.

In accordance with the present invention, electrical connectors may be manufactured which have the crimp bucket n~n flfl~~flm 16 arranged in any desired orientation with respect to the forwardly extending blade. Figures 11 through 38 show electrical connectors in accordance with embodiments of the present invention with the crimp buckets having different orientations. The same reference numerals are used throughout the figures to indicate the same c6mponents.

Note that were dimensions are indicated (in millimetres) they are exemplary only, and connectors having different dimensions may be manufactured in accordance with the present invention.

The connector of figures 15 through 17 is intended for use as a neutral pin arranged to receive a vertical crimp when placed in a plug partition crimp approaching from the vertical). As in figure 10. In this case, the blade element is non insulated.

The electrical connector of figures 22 through 24 is intended as a active conductor for a plug, with a vertical crimp to be employed.

The electrical connector of figures 29 through 31 is intended as an earth conductor to be employed in a plug body, employing a vertical crimp. In this connector, the open top of the bucket crimp receptacle is oriented at approximately 900 to the transverse symmetrical plane of the flat blade element 4.

The electrical connector of figures 32 through 38 is an alternative version of an earth pin showing a normal type crimp bucket with the crimp bucket being in the same orientation as the blade connector. This crimp does incorporate the neck portion in accordance with the embodiments of the present invention, however.

Note that when manufacturing a pin in accordance with an embodiment of the present invention, it is important to ensure that the neck portion is of sufficient dimensions to carry the required amount of current.

Figures 17, 24, 31 and 38 show the electrical 17 connectors mounted on a former strip 40. Conventionally, when plug pins are manufactured, a plurality of them are manufactured from a substrate of conductive material. The substrate is first "blanked" to form a plurality of blanks attached to a former strip. The blanks are then folded to form the plug pin as illustrated in the figures 17, 24, 31 and 38, (showing connectors in accordance with the present invention) before finally being removed from the former strip for assembly into plug bodies. In automated assembly of plug bodies, the plug pins will usually be provided on the former strip until a stage when they are to be inserted into a plug, and only then will they be removed from the former strip.

Figures 39 through 47 illustrate stages in manufacture of a rearwardly extending bucket crimp of connectors in accordance with embodiments of the present invention.

Figures 39 through 41 show stages in the manufacture of the vertical crimp pins illustrated in figures 29 through 31. Note that in each figure, views and are bottom plan, side and rear views, respectively.

In each figure the forwardly extending flat blade element is shown already formed. It may be already formed, or it could be formed at the same time as the bucket crimp is being formed.

Referring to figure 39, before any folding takes place, the blank for forming the connector is stamped from the conductive substrate. The neck portion 8 is formed by stamping to be the shape shown, providing for an area 9 (fold area) along which the portion 8 can be folded to adjust the angle of orientation of the bucket 6.

In stage 2, the sides of the blank are folded upwards to form the bucket crimp 6, and in stage 3 (figure 41) the neck portion 8 is folded to orientate the bucket crimp 6 as shown. Similar steps are undertaken for live conductors (figures 42 through 44) and neutral conductors (figures 18 through 47). The orientations of the bucket crimp 6 in each stage are merely folded to orientate differently.

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.

onf\ ff 7O2OC A-

Claims (2)

1. 2. A plurality of plug pin connectors in accordance with claim i, wherein the crimp receptacle of each plug pin is oriented with respect to the non-circular element at an angle of rotation about an axis that is coincident with or parallel to the longitudinal axis of the non-circular element, the angles of rotation for each plug-pin connector being different.
2. 3. A plurality of plug pin connectors in accordance with claim 1 and substantially as herein described with reference to the accompanying drawings. Dated this 27th Day of September, 1999 UTILUX PTY LIMITED By their Patent Attorneys GRIFFITH HACK J:\Speci\300 399\300 349\32752.doc