EP2183822B1

EP2183822B1 - Electrical contact

Info

Publication number: EP2183822B1
Application number: EP08786714.9A
Authority: EP
Inventors: Bruce Kent; Andrew Mcquilken
Original assignee: Harwin PLC
Current assignee: Harwin PLC
Priority date: 2007-08-01
Filing date: 2008-07-31
Publication date: 2015-09-30
Anticipated expiration: 2028-07-31
Also published as: GB0714969D0; EP2183822A2; WO2009016243A3; WO2009016243A2

Description

The present invention relates to electrical contacts and a method of manufacture of such contacts.
An electrical connection can be made between two electrical devices usually using a male and female electrical contact. One part of the connection has a male contact with an electrical pin and the other part is a female contact in the form of a socket for receiving the male contact.
Known male and female contacts include a tubular shaped contact section which has a square or circular cross section and receives a conducting portion of a male contact. The forces exerted by the conducting portion of the male contact on the contact section can vary in such configurations and affect the stress /strain of the contact section thereby affecting the performance and durability of the connector.
GB 826825 A relates to a socket contact is bent up from a sheet-metal blank to form a resilient, triangular, pin receiving portion with a depending terminal tag formed with lateral wings having outwardly inclined tongues at their upper ends, so that when the contact is inserted in a shouldered aperture in an insulating support, the lower end of portion abuts the shoulder and the tongues snap into engagement with the lower face of the support to prevent removal of the contact. The lower end of the portion is closed by an integral, bent-over tab.
FR 1440488 A discloses a female contact according to the preamble of claim 1 and further relates to contact housing that is folded out of sheet metal for receiving a contact pin. Leading cut out strips are provided that are directed towards the opening that receives the contact pin.
DE 198 26 828 A and US 6004169 relate to contacts that have two compliance points.
US 5209680 , DE 703904C , and EP 1239547 A disclose examples of a male electrical terminal. DE 14 65 765A discloses a made contact according to the preamble of claim 9.
From a first aspect, the present invention comprises a female electrical contact according to appended claim 1. The contact elements are preferably evenly distributed in the triangular portion.
From a second aspect, the present invention provides a method of manufacturing a female electrical contact according to appended claim 9. This is advantageously formed by carrying out a bending and cutting process from a single sheet of material. One of the advantages is the ease of manufacture of such a contact.
From a third aspect, the present invention provides a male electrical contact according to appended claim 10. The outer surfaces of the pin are aligned to form a triangular shape.
From a fourth aspect, the present invention provides a method of manufacturing a male electrical contact according to appended claim 18. This is advantageously formed by carrying out a bending and cutting process from a single sheet of material. One of the advantages is the ease of manufacture of such a contact. In order that the present invention be more readily understood, embodiments thereof will be described by way of example with reference to the accompanying drawings, in which:

Fig 1 is a perspective view of a reel for supplying female contacts according to a preferred embodiment of the present invention;
Fig 2 is a perspective view of two female contacts according to a preferred embodiment of the present invention taken from the reel of Fig. 1;
Fig. 3 is a view from above one of the contacts shown in Fig. 2;
Fig. 4 is a side view of one of the contacts shown in Fig. 2;
Fig. 5 is a cross sectional view of the contact taken along line V-V in Fig. 4;
Fig. 6 is a cross sectional view of the contact taken along the line VI-VI in Fig. 4;
Fig. 7 is a cross sectional view of the contact taken along the line VII-VII in Fig. 4;
Fig. 8 is a simplified elevational view showing one arrangement of a plurality of connectors located within a connector housing;
Fig. 9 is a simplified elevational view showing another arrangement of a plurality of connectors located within a connector housing;
Fig. 10 is a perspective view of a reel for supplying male contacts according to a preferred embodiment of the present invention;
Fig 11 is a first perspective view of two female contacts according to a preferred embodiment of the present invention taken from the reel of Fig. 10;
Fig. 12 is a second perspective view of one of the female contacts shown in Fig. 11;
Fig. 13 is a view from above the contacts shown in Fig. 12;
Fig. 14 is a side view of one of the contacts shown in Fig. 12;
Fig. 15 is a cross sectional view of the contact taken along line XIII-XIII in Fig. 14;
Fig. 16 is a cross sectional view of the contact taken along the line XVI-XVI in Fig. 14;
Fig. 17 is a cross sectional view of the contact taken along the line XVII-XVII in Fig. 14;

Referring to Fig. 1, a reel 1 of female electrical contacts 10 is provided wherein each electrical contact 10 is identical to the next and therefore a single reference numeral will be used to refer to each contact in the following description. The electrical contacts 10 are formed from a conductive material such as beryllium copper. Other materials may be used. A suitable protective paper such as interleave paper 11 is provided in the reel to protect the electrical contacts.
In the manufacturing process (not shown), a sheet of the conductive material can be pressed to form various shaped portions which are subsequently folded into the shape of the electrical contact. Accordingly the electrical contacts 10 are advantageously formed from a single sheet of conductive material improving the manufacturing process.
The electrical contacts according to a preferred embodiment of the invention are shown in more detail in Fig. 2 to 6. Two contacts are shown in Fig. 2 but each is identical. Only one of the contacts will be discussed in more detail although the description applies to each contact.
The electrical contact 10 is the female portion of an electrical connector which forms a connection with a male contact (not shown). It comprises a contact section 20 for receiving and contacting an electrical pin or plug (not shown) of the male contact and a connection section 30 for connecting to a conducting wire (not shown).
The contact section 20 has a channel of triangular cross section. The triangular shape of the channel can be created in the manufacturing process by folding two extensions of a sheet (not shown) of conductive material towards each other such that the channel has a base 21 and a first and second side 22,23. A small gap 24 will exist at the top of the first and second side 22,23 but this can be kept as small as possible.
The base 21 and first and second side 22,23 of the channel each comprise a cut away portion 25 to create an electrical finger or element 21a,22a,23a. The electrical elements 21a,22a,23a are movable and at least part of each contact is disposed within the channel. This can be achieved when manufacturing by bending the elements towards the centre of the channel and away from each planar surface of the base 21, first and second side 22,23 of the channel. Sufficient forces are provided such that the elements 21a,22a,23a remain at least partially bent inwards in their rest position. The elements 21a,22a,23a point in a direction away from the entrance of the contact section 20 such that they converge in the direction of insertion of a pin of a male contact. The elements 21a,22a,23a converge towards a central longitudinal axis A of the contact section 20.
Accordingly, the contact section 20 has three flat electrical elements 21a,22a,23a which are evenly distributed in the channel and would be evenly distributed around a pin of a male contact when received by the female contact 1. Each element 21a,22a,23a has a similar cross section to that of the base, first, and second side of the channel thus in this case the section is rectangular. Since the elements 21a,22a,23a are formed from flat sides, they themselves are flat. This differs to a circular cross section channel which can be found in conventional female contacts where the elements have an arc section.
With the three element configuration in the preferred embodiment, the deflection stress/strain of the element 21a,22a,23a would be reduced when the pin of the male contact is mated with the female contact 10. This allows for less permanent set for a given deflection of the three elements and hence a greater number of contact mating cycles with a reduced loss in contact element normal force. A greater number of operations are therefore possible. This is achieved while still maintaining other high reliability performance factors comparable to those only usually obtainable from multi-finger circular contacts. Further, the design of the female contact also benefits the manufacturing process due to less unwanted distortion.
In addition, with the contact 10 having a triangular cross section, they can be arranged adjacent each other in a housing 40 as shown in Figure 8. However, it is possible to arrange the contacts 10 close together when each contact is orientated at 180 degrees to the adjacent contact 10. For example, as shown in Figure 9 which shows one possible configuration, the contacts 10a, 10b are arranged in a housing 50 with the base 21 of one contact 10a (viewed in cross section) being aligned next to an apex 26 of another adjacent contact 10b and this can be repeated for a larger housing. It should be noted that all the parts of the contact as shown and described in Figure 2 to 7 have not been shown in Figure 8 and 9 but only a simplified view is shown for ease of explanation.
The connection section 30 can formed from the same sheet (not shown) of conductive material that is used for the contact section 20 and follows from the channel in the contact section 20 to provide a connection channel. A first and second U-shaped portion 31, 32 is formed from the sheet by bringing legs projecting away from the connection channel towards each other to create a two U-shapes 31,32. The end of the legs in the portion 31 are spaced further than the ends of the legs in portion 32. It will be appreciated that the spacing between the legs in portion 31 and portion 32 can be varied such that the ends of the legs in portion 32 are spaced apart further than those in portion 31.
In use, the connection section provides electrical connection to a circuit by receiving a conducting wire (not shown) for which electrical connection is to be made with the received pin of the male contact. The U shaped portions 31,32 can be crimped by any suitable means such as crimping pliers to engage the wire.
The electrical contact 10 is preferably contained in a housing. A retaining member 33 is provided on the contact 10 to retain the contact 10 in the housing. Furthermore, particular sections of the contact 10 may be provided with certain finishes to improve their durability and performance. For example, part or the entire contact 10 may be gold plated to improve conductivity.
It will be appreciated that although the contacts are shown as forming part of a reel in Fig. 1, it is possible for the contacts to be provided loose.
Turning to another aspect, a male contact designed to cooperate with the female contact 10 hereinbefore described will now be described with reference to Figures 10 to 18. The male contact includes a triangular cross section which can be received by the female contact described hereinbefore and replaces a male contact with circular cross section. The male contact can be formed in a similar manner by means of folding a sheet of material in a particular manner to form the contact. Thus the contact can be manufactured easily from a single sheet of material (as will be explained below).
Referring to Fig. 10, a reel 100 of male electrical contacts 60 is provided wherein each electrical contact 60 is identical to the next and therefore a single reference numeral will be used to refer to each contact in the following description. The electrical contacts 10 are formed from a conductive material such as beryllium copper. Other materials may be used. A suitable protective paper such as interleave paper 11 is provided in the reel to protect the electrical contacts. The paper 11 is the same as that used in Figure 1.
In the manufacturing process (not shown), a sheet of the conductive material can be pressed to form various shaped portions which are subsequently folded into the shape of the electrical contact. Accordingly the electrical contacts 10 are advantageously formed from a single sheet of conductive material improving the manufacturing process.
The electrical contacts according to a preferred embodiment of the invention are shown in more detail in Fig. 11 to 15. Two contacts are shown in Fig. 11 but each is identical. Only one of the contacts will be discussed in more detail although the description applies to each contact.
The electrical contact 10 is the male portion of an electrical connector which forms a connection with a female contact such as that described hereinbefore. It comprises a contact section 70 which is inserted into a female contact and contacts an electrical conductor in the female contact and a connection section 80 for connecting to a conducting wire (not shown).
The contact section 70 generally has a triangular cross section. The triangular shape of the channel can be created in the manufacturing process by folding a sheet (not shown) of conductive material in two places towards each other such that the channel has a base 71 and a first and second side 72,73. Each of the base 71, first and second side 72,73 have a narrow portion which form extensions 71a,72a,73a. The extensions can be formed prior to bending by cutting away portions of the conductive material to leave three extension pieces which are parallel to each other. The narrow portions extend away from the part of the material forming the base, first and second side. When the first and second side 72,73 are bent towards each other with respect to the base 71, this also brings extensions 72a, 73a towards each other. The extensions 71a,72a,73a can be crimped to create a contact pin with a triangular cross section by bending the extensions inwards towards a central longitudinal axis B of the contact 60 and then bending them to be parallel with the central longitudinal axis B. Accordingly, the extensions 71a,72a,73a comprise an angled portion and a rectilinear portion.
Sufficient forces are provided. The crimping step results in the extensions 71a,72a,73a being biased towards each other such that the extensions 71a,72a,73a remain in this configuration in their rest position.
The contact pin is therefore formed of three surfaces arranged generally at 120 degrees to each other. The three extensions 71a,72a,73a that form the contact pin would physically contact the elements 21a,22a,23a of the female contact 10 described previously and this would provide a reliable electrical connection between the male and female contacts. Each extension 71a,72a,73a has a similar cross section to that of the base 71, first 72, and second side 73 of the channel thus in this case the section is rectangular. Since the extensions 71a,72a,73a are formed from flat sides, they themselves are substantially flat. This differs to a circular pin which can be found in conventional male contacts where the pin is has a solid circular cross section.
Although the contact pin is substantially flat, the end portions of the extensions 71a,72a,73a can be tapered inwards towards the central longitudinal axis B such that the ends of the extensions 71a,72a,73a abut each other. Furthermore, the width of the extensions is constant except for the end portions where the sides of each extension converge towards the end of the extension. This enables the end portions to be bent inwards towards the central longitudinal axis such that they cooperate with each other at the end of the contact pin leaving a negligible gap at the end of the contact pin.
The deflection stress/strain of the element 21a,22a,23a in the female contact 10 is reduced when the particular shape of contact pin of the male contact 60 is mated with the female contact 10. This allows for less permanent set for a given deflection of the three elements and hence a greater number of contact mating cycles with a reduced loss in contact element normal force. A greater number of operations are therefore possible. This is achieved while still maintaining other high reliability performance factors comparable to those only usually obtainable from multi-finger circular contacts in conventional contacts.
The connection section 80 can be formed from the same sheet (not shown) of conductive material that is used for the contact section 70 and follows from the channel in the contact section 70 to provide a connection channel. A first and second U-shaped portion 81, 82 (see Figures 16 and 17) is formed from the sheet by bringing legs projecting away from the connection channel towards each other to create a two U-shapes 81,82. The end of the legs in the portion 81 are spaced further than the ends of the legs in portion 82. It will be appreciated that the spacing between the legs in portion 81 and portion 32 can be varied such that the ends of the legs in portion 82 are spaced apart further than the those in portion 31. The length of the legs can also vary. Figure 18 shows an embodiment of a male contact with the U-shaped legs 92 being shorter than the legs 82 in Figure 12. Otherwise, the elements of the contact are the same in both embodiments.
In use, the connection section provides electrical connection to a circuit by receiving a conducting wire (not shown) for which electrical connection is to be made with the received pin of the male contact. The U shaped portions 81,82 can be crimped by any suitable means such as crimping pliers to engage the wire.
The electrical contact 60 is preferably contained in a housing (not shown). A retaining member 83 is provided on the contact 60 to retain the contact 60 in the housing. Furthermore, particular sections of the contact 60 may be provided with certain finishes to improve their durability and performance. For example, part or the entire contact 60 may be gold plated to improve conductivity.
It will be appreciated that although the contacts are shown as forming part of a reel in Fig. 10, it is possible for the contacts to be provided loose.

Claims

A female electrical contact for an electrical connector having a contact section (20) comprising an opening for receiving an electrical pin of a male contact, the contact section forming a channel having a triangular cross section wherein the contact section comprises a base (21) and two upstanding portions (22, 23) from the edges of the base (21), each having a planar surface and the contact section further comprises three conductive fingers (21 a, 22a, 23a), each finger being formed respectively from cutaway portions of the base and two upstanding portions, each conductive finger (21 a, 22a, 23a) being arranged to converge towards a central longitudinal axis (A) of the contact section, the convergence of each finger is away from the opening and away from each planar surface of the base and two upstanding portions characterised in that each conductive finger is pointed away from the opening and are themselves flat.
The female contact according to claim 1, wherein the contact section is formed from a single electrically conductive sheet.
The female contact according to claim 2, wherein the contact section is formed by bending two extensions from the conductive sheet towards each other.
The female contact according to any preceding claim wherein the contact section further comprises a retaining means (33) for retaining the contact in a housing.
A connector having a connector housing (40, 50) comprising a female electrical contact (10, 10a, 10b) according to any of claims 1 to 4.
The connector according to claim 5, wherein there is a plurality of female electrical contacts (10, 10a, 10b) arranged adjacent each other within the connector housing.
The connector according to claim 6, wherein, each contact (10a, 10b) is arranged at 180 degrees to an adjacent contact.
A method of manufacturing a female electrical contact according to any of claims 1 to 4 for an electrical connector, comprising the steps of:
forming a contact section with a triangular cross section for receiving an electrical pin of a male contact through an opening in the contact section wherein the forming step comprises bending two extensions from a single electrically conductive sheet towards each other to create a base portion and two upstanding portions, the method characterised by the step of providing inwardly directed fingers in the contact portion by bending inwards cutaway portions of the base portion, and the two upstanding portions away from the opening.
A male electrical contact for an electrical connector having a contact section (70) for cooperating with a female electrical contact according to any of claims 1 to 4, the contact section comprises a contact pin having a triangular cross section, characterised in that the contact section further comprises a base (71) and two upstanding portions (72, 73) from the edges of the base, and a plurality of extensions (71 a, 72a, 73a), the extensions extending from the respective base and two upstanding portions.
The male contact according to claim 9, wherein the contact section is formed from a single electrically conductive sheet.
The male contact according to claim 10, wherein the contact section is formed by bending two portions of the conductive sheet towards each other.
The male contact according to claims 9, 10, or 11, wherein sides of an end portion of the extension are tapered inwards.
The male contact according to any of claims 9 to 12 wherein an end portion of the extension converges towards a central longitudinal axis (B) of the contact section.
The male contact according to any of claims 9 to 13, wherein the contact section further comprises a retaining means (83) for retaining the contact in a housing.
The male contact according to any of claims 9 to 14 wherein the plurality of extensions are adapted to be crimped together such that the extensions are aligned with each other and biased towards each other to form an elongate contact pin.
A connector having a connector housing comprising a male electrical contact according to any of claims 9 to 15.
A method of manufacturing a male electrical contact according to any of claims 9 to 15 for an electrical connector, characterised by the steps of:
forming a contact pin with a triangular cross section for inserting into a female contact as defined in any of claims 1 to 4, wherein the forming step comprises cutting away parts of the single conductive sheet to form extensions and bending respective portions containing the cut away extensions towards each other to create a base portion and two upstanding portions.
The method according to claim 17 wherein the forming step further comprises cutting away sides of the of the extensions to form a tapered end portion.
The method according to claims 17 or 18 wherein the forming step further comprises bending the end of the extension towards a central longitudinal axis.