EP1973200A1

EP1973200A1 - Connector

Info

Publication number: EP1973200A1
Application number: EP08102735A
Authority: EP
Inventors: Nurz Litton Zaman
Original assignee: Yazaki Europe Ltd
Current assignee: Yazaki Europe Ltd
Priority date: 2007-03-20
Filing date: 2008-03-18
Publication date: 2008-09-24
Also published as: GB0705313D0

Abstract

There is disclosed a method of providing, at a wire end, a connector to be connectable with a connection point, the method comprising shaping the wire end to form the connector.

There is also disclosed a connector provided at a wire end and being connectable with a connection point, the connector being shaped from the wire end.

Description

The present invention relates to a method of providing a connector at a wire end. The invention also relates to a connector formed at a wire end. The invention has been devised particularly, though not necessarily solely, in respect of terminal connectors.
Throughout this specification, the term "wire" will be understood as a reference to the conductive part of an electrical wire or cable, such as a conductive core of such a wire or cable. Moreover, throughout this specification, the term "connection point" will be understood as a reference to anything to which the connector can be connected to form an electrical connection, such as, for example, another connector, a battery terminal or a grounding point.
The range of components in the field of electrical wiring and cabling is replete with connectors having a multitude of shapes and sizes. In circumstances where a reliable connection is required, particularly where that connection is to be releasable, it is common to fix, for example by soldering or crimping, a pre-formed connector to a wire end. The connector may be connectable with another connector, which might be part of an electrical component or terminal block, or may itself be preformed and fixed to a wire end.
Numerous problems can arise where a pre-formed connector is fixed to a wire end. For example, poor workmanship during fixing and/or deterioration of the fixing over time can result in a poor electrical connection between the wire and the connector. Moreover, there is often a need to match the connectors to be connected, which can introduce difficulties and delays.
According to a first aspect of the invention, there is provided a method of providing, at a wire end, a connector to be connectable with a connection point, the method comprising shaping the wire end to form the connector.
According to a second aspect of the invention, there is provided a connector provided at a wire end and being connectable with a connection point, the connector being shaped from the wire end.
In the drawings:

Figure. 1A is a cross-sectional and perspective view of a multi-stranded wire to which the invention is applicable;
Figure 1B is a cross-sectional and perspective view of an end of the wire shown in Figure 1A after being subjected to consolidation by ultrasonic welding;
Figure 1C is a cross-sectional and perspective view of an end of the wire shown in Figure 1A after consolidation of the strands by resist welding;
Figures 2A to 2D depict stages in the shaping of a wire end into a connector by stamping, in accordance with an example of the invention;
Figures 3A to 3D depict stages of shaping the end of the wire into a connector by press-forming, in accordance with an example of the invention;
Figure 4A and 4B depict shaping of a wire end by laser cutting, in accordance with an example of the invention;
Figures 5A to 5C depict stages in a method of forming a connector at the end of a wire according to a first embodiment of the invention;
Figures 6A to 6C depict stages in a method of forming a connector at the end of a wire according to a second embodiment of the invention;
Figures 7A to 7C depict stages in a method of forming a connector at the end of a wire according to a third embodiment of the invention;
Figures 8A to 8C depict stages in a method of forming a connector at the end of a wire according to a fourth embodiment of the invention; and
Figure 9A is a perspective view of blade (male) and receptacle (female) connectors which may be produced according to an embodiment of the invention;
Figure 9B is a perspective view of a ring connector which may be produced according to an embodiment of the invention; and
Figure 9C is a perspective view of a spade connector which may be produced according to an embodiment of the invention.

Each of the embodiments described in detail below involves the formation of a connector at a wire end 10, as depicted as in Figure 1, which comprises multiple strands 12 of conductive material such as copper. However, as will be apparent from the following description, the invention is not limited to wires comprising multiple strands and is, for example, equally applicable to wires comprising a single piece of conductive material such as a solid conductive core.
Common to each of the embodiments described in detail below are the steps of:

(a) consolidation of the strands 12 at the wire end 10;
(b) shaping the wire end 10, either during, or subsequent to, consolidation, such as by way of stamping, press forming or laser cutting; and
(c) providing a surface finish after shaping.

At the outset, it should be noted that the wire end may be formed by aggregating a plurality of wire ends, for example in the case of a grounding point on a motor vehicle chassis where such a plurality of wire ends must be electrically connected.
It must also be recognised that there will be circumstances where consolidation is not required, such as where the wire is a solid conductive core or where strands of the wire end are tightly grouped together.
Prior to consolidation of the strands, i.e. forcing and/or joining of the strands together such that they are formed into a compact mass, it will usually be necessary to remove exterior layers, such as insulation, sheathing and the like, to expose the wire end 10.
The means of consolidating the wire end 10 is determined according to the specific application. Where a relatively low degree of continuity between, and mechanical strength of, the consolidated strands 12 is required, the strands 12 of the wire end 10 may be consolidated by means of ultrasonic welding, to produce a cross-sectional configuration such as that shown in Figure 1B. Ultrasonic welding may also be employed where the wire end 10 is to be formed from a plurality of wire ends comprising dissimilar materials.
Consolidation by ultrasonic welding involves delivery of energy into the wire end 10 in the form of high-power ultrasound. This type of welding may also be beneficial where the wire end, or the connector to be formed at that end, is small, complex or too delicate for more common welding techniques.
Ultrasonic welding involves sandwiching the wire end 10 between two members, generally a shaped nest and a sonotrode. The ultrasonic energy causes melting at points of contact between the strands, thereby joining and consolidating them.
The strands may also be consolidated by resistance welding, as an alternative or subsequent step to ultrasonic welding (see Figure 1 C). Resistance welding involves clamping the wire end 10 between two electrodes, so as to compress the strands 12, and passing current through the end 10 to cause melting and bonding at the positions where adjacent strands contact each other. Resistance welding, which may comprise spot welding, shot welding (in the case of stainless steel strands) and/or seam welding, generally provides for a high weld strength between strands, which may give rise to more compactly consolidated strands 12 having better electrical continuity and affording the end better mechanical strength.
Furthermore, the strands may be consolidated by friction bonding, which gives rise to strong joins without welding, or merely by the application of sufficient external pressure to force the strands together sufficiently tightly. When the conductive material of the end 10 is sufficiently consolidated, the end 10, if not appropriately shaped as a result of consolidation, is shaped.
It will be appreciated that shaping, in its broadest sense, might involve nothing more than allowing the wire end to remain in the shape it is in to start with, such as in cases where the connector is intended to have a circular cross-section and the wire end is, similarly, circular in cross-section at the outset.
Shaping may be carried out by stamping (see Figures 2A to 2D), press-forming (see Figures 3A to 3D) and/or laser cutting (see Figures 4A and 4B), as discussed below.
The end 10 may be shaped by stamping, particularly in the case where it is to be configured as a female connector. In the example stamping process shown in Figures 2A to 2D, the end 10 is firstly stamped flat (Figure 2A), then subjected to stamping between appropriately-shaped members so as to produce the final connector configuration shown in Figure 2D, the configuration defining an interior space 14 which may receive a connection point (e.g. another connector) such that a connection is formed. The interior space 14 may have a cross-sectional dimension which is slightly smaller than a cross-sectional dimension of a portion of the connection point to be received therein so as to frictionally engage the connection point and thus to resist disconnection.
The end 10 may also be shaped by press-forming, particularly in the case where it is to be formed into a male connector (see Figures 3A to 3D). Press forming involves compressing the end 10 (see Figure 3A) between a plurality of pressing members 16 (see Figure 3B), for example in a die, to shape the end 10, thereby giving rise to an end configuration conforming to the configuration defined by the die 16 (see Figure 3C). The end 10 thus configured may then, if necessary, be further shaped, for example into a more complex or intricate configuration, by being pressed between pressing members 18 of a further die.
Furthermore, the end 10 may be shaped by laser cutting, particularly in the case where the connector is to be generally planar or can be formed from the wire end 10 flattened. Specifically, the end 10 may be cut using a laser cutter 20, for example to configure the end 10 as an eye 22 or ring (see Figures 4A and 4B).
In addition, the wire end 10 may, advantageously, be shaped by being compressed in a conventional crimping tool, so as to render the shape of the end 10 the same as that of a separate connector which would otherwise be crimped onto that end and shaped appropriately by the crimping tool.
Shaping of the end 10 may, alternatively or additionally, be carried out by forging, moulding, cold forming, micro-forming, macro-forming and/or milling.
It will be appreciated that shaping may involve a combination of any two or more of the techniques described above and may be facilitated by heating of the wire end.
Following shaping of the end 10, the end 10 is subjected to an appropriate finishing method which may comprise tinning, such as by dipping the shaped end into a solder bath or applying solder paste to the shaped end and processing the end through an oven, electrolysis or spraying metallic powder, in a hot or cold form, onto the end (e.g. via cold gas deposition or plasma spray coating).
A description of a method of forming a connector according to four specific embodiments will now be provided.
The method of forming a connector according to the first embodiment (see Figures 5A to 5C) involves removing the insulation and other material from the wire end 10 to expose the strands 12 (see Figure 5A), then compressing and welding the strands 12 at the end 10 (see Figure 5B).
Next, the end 10 is subjected to a press-forming process, as outlined above with reference to Figures 3A to 3D, to produce a male connector 30 having a solid rectangular or square cross-section or a female connector 30 arranged to receive a male connector (see Figure 5C). The female connector 30 may be formed by arranging the strands 12 (prior to consolidation) around an appropriately-shaped member (not shown) and consolidating them (as shown in Figure 5B), to define space 14 then removing the member from the end of the wire end 10. Alternatively, the female connector 30 may be formed via the stamping process described above with reference to Figures 2A to 2D. It will be appreciated that the external cross-sectional configuration of the male or female connector 30, as formed via the steps described with reference to Figures 5A to 5C, as well as the cross-sectional configuration of the space 14, may be something other than square or rectangular. The space 14 may have a cross-sectional dimension which is slightly smaller than a cross-sectional dimension of a portion of the connection point (e.g. the male connector 30 depicted in Figure 5C) to be received therein so as to frictionally engage the connection point and thus resist disconnection. Also, the male connector 30 may have a cross-sectional dimension which is slightly larger than a cross-sectional dimension of a portion of the connection point (e.g. the female connector 30 depicted in Figure 5C) in which it is to be received so as to frictionally engage the connection point and thus resist disconnection.
Finally, the end 10 is subjected to appropriate surface finishing via any of the methods described above.
The method of forming a connector according to the second embodiment (see Figures 6A to 6C) involves exposing the end 10 (Figure 6A), then flattening the end 10, either during or after consolidation via any of the aforementioned consolidation techniques. In this embodiment, shaping the wire end 10 comprises flattening the wire end 10 such that it occupies a plane, so as to create a divergent, or generally v-shaped, end profile in the plane. The shaping may be carried out by stamping, as described above with reference to Figure 2A. Where flattening and consolidation are to be simultaneous, the end 10 may be clamped between the electrodes of a resistance welding apparatus, such that the end 10 is flattened, and then, while remaining clamped, subjected to current passed through the conductive material to weld the strands 12.
Following flattening and consolidation, the end 10 is stamped and/or laser cut so as to be configured as an eyelet, C-shaped connector, spade connector or fork-type connector (see Figure 6C). The end 10 is then subjected to appropriate surface finishing via any of the methods described above.
The method of forming a connector according to the third embodiment (see Figures 7A to 7C) is the same as that according to the second embodiment though involves creating a rectangular, rather than divergent, end profile in the plane (see Figure 7B), that profile being created by, for example, stamping and/or laser cutting as described above, and then creating an eyelet such as by stamping and/or laser cutting, the eyelet having a rectangular, rather than circular, configuration.
The end 10 may, in a further step, be bent at an angle to the plane, as shown in Figure 7C, either before or after surface finishing by means of any of the methods described above.
The method of forming a connector according to the fourth embodiment (see Figures 8A to 8C) involves aggregating a plurality of wire ends 10' to form the wire end 10. In this embodiment, the wire ends 10' are aggregated by being intermeshed and are interconnected, by interdigitating, interlacing and/or interweaving of their strands, after initial separation of the strands of each wire end 10' if necessary.
In another embodiment, the wire ends 10' are interconnected by intertwining. Specifically, in one variant of that embodiment, wire strands of each wire end 10' are intertwined with wire strands of at least one other wire end 10'. In another variant of that embodiment, each wire end 10' is, in its entirety, intertwined with at least one other wire end 10' in its entirety.
In this embodiment, shaping the wire end 10, as formed by aggregating the plurality of wire ends 10', comprises flattening the wire end 10 such that it occupies a plane, so as to create a divergent, or generally v-shaped, end profile in the plane. The shaping may be carried out by stamping, as described above with reference to Figure 2A. Where flattening and consolidation are to be simultaneous, the end 10 may be clamped between the electrodes of a resistance welding apparatus, such that the end 10 is flattened, and then, while remaining clamped, subjected to current passed through the conductive material to weld the strands 12.
Following flattening and consolidation, the end 10 is subjected to the same shaping and surface treatment steps as described in connection with the second embodiment. In a variation of the fourth embodiment, the end 10 may be subjected to the same shaping steps as described in connection with the first and third embodiments or indeed any of the various methods of shaping referred to above.
It will be appreciated that there is a wide range of alternative shapes of connector into which the wire end can be configured according to the invention. Examples of particular connector types which may be formed according to the invention are illustrated in Figures 9A to 9C. Figure 9A is shows a blade (male) connector 40A and a receptacle (female) connector 40B, which is mateable with the blade connector, each of which may be formed in accordance with the invention. Figures 9B and 9C show a ring connector 42 and spade connector 44, respectively, which may both be formed in accordance with the invention. Common to all of these connectors is a profiled portion having a profile which is complementary to that of a portion of the other connector with which the profiled portion mates when the connection is formed.

Claims

A method of providing, at a wire end, a connector to be connectable with a connection point, the method comprising shaping the wire end to form the connector.
A method according to claim 1, wherein shaping the wire end comprises press-forming the wire end.
A method according to claim 1 or claim 2, wherein shaping the wire end comprises cutting the wire end.
A method according to any of the preceding claims, wherein shaping the wire end comprises stamping the wire end.
A method according to any of the preceding claims, wherein shaping the wire end comprises forming the wire end using a crimping tool.
A method according to any of the preceding claims, wherein shaping the wire end comprises flattening the wire end.
A method according to any of the preceding claims, further comprising heating the wire end to facilitate shaping.
A method according to any of the preceding claims, comprising shaping the wire end such that the connector comprises a portion having a profile which is complementary to that of a portion of the connection point, whereby the connector is mateable with the connection point.
A method according to any of the preceding claims, wherein shaping the wire end comprises forming in the wire end a space into which the connection point is receivable.
A method according to any of the preceding claims, comprising consolidating strands of the wire end.
A method according to claim 10, wherein consolidating the strands comprises welding the strands together.
A method according to claim 11, wherein the welding comprises ultrasonic welding.
A method according to claim 11 or claim 12, wherein the welding comprises resistance welding.
A method according to claim 13, wherein the resistance welding comprises spot welding, shot welding and/or seam welding.
A method according to any of claims 10 to 14, wherein consolidating the strands comprises friction bonding the strands.
A method according to any of the preceding claims, comprising aggregating a plurality of wire ends to form said wire end.
A method according to claim 16, wherein aggregating the plurality of wire ends comprises intermeshing strands of the wire ends.
A method according to claim 16 or claim 17, comprising interconnecting the wire ends.
A method according to claim 18, wherein interconnecting the wire ends comprises intertwining each wire end with at least one of the other wire ends.
A method according to claim 18 as appended to claim 17, wherein interconnecting the wire ends comprises intertwining the strands of one wire end with strands at least one of the other wire ends.
A method according to any of the preceding claims, comprising shaping the wire end to define a blade-type, receptacle-type, spade or ring connector.
A connector provided at a wire end and being connectable with a connection point, the connector being shaped from the wire end.