GB2428907A

GB2428907A - Shielded socket assembly

Info

Publication number: GB2428907A
Application number: GB0516229A
Authority: GB
Inventors: Matthew Pine
Original assignee: EDS DEVELOPMENTS Ltd
Current assignee: EDS DEVELOPMENTS Ltd
Priority date: 2005-08-05
Filing date: 2005-08-05
Publication date: 2007-02-07
Also published as: GB0516229D0

Abstract

A shielded connector comprises plural contacts 14 and at least one electrical shield disposed between two adjacent contacts, the shield comprising one or more planar portions. To make the connector, a continuous strip of individual planar shields (30, figure 3, not shown) is overmoulded with corresponding individual plastics module bodies 20 (figure 4) and strip parts 32 joining the shields are severed. A contact 14 is inserted in each module body 20 and plural module bodies are assembled by locating ribs in corresponding grooves in adjactent module bodies, optionally by snap fitting. A contact may be coated with metal. The plural module bodies may be assembled in a housing (12, figure 2, not shown) to form an RJ45 socket connector.

Description

1 2428907

SHIELDED SOCKET ASSEMBLY

The present application relates to a shielded socket assembly and a method of manufacturing such an assembly.

Electrical and electronic systems are subject to a variety of technical standards that set minimum requirements covering, for example, maximum data rates and operating frequencies that may be applied across certain sections of the electronic and electrical systems. Included within certain of the standards are the communication cables, cable terminations and sockets.

Such cables and their respective connectors typically use multiple cores, that is to say the cable actually comprises of a number of individual conductors. The characteristics of such cables and their associated connectors dictated by the standards include, amongst others, the insertion loss, near end cross talk, return loss and equal level far end cross talk. These characteristics tend to dictate the signal-to-noise ratio of the cable and its connectors, which is a critical measure determining the maximum data rate of the cable. One of the important features of the design of the cables and their associated terminations and sockets that influences the performance of the cable and connections in terms of the previously mentioned criteria is the electrical shielding provided between the respective conductors within the cable and connectors.

According to a first embodiment of the present invention there is provided a shielded socket assembly comprising a plurality of electrical contacts and at least one electrical shield disposed between two adjacent electrical contacts, the shield comprising one or more substantially planar portions.

According to a second embodiment of the present invention there is provided a method of manufacture of a shielded socket assembly, the method comprising: forming a plurality of contact support blocks, at least one of which comprises an electrical shield having one or more substantially planar portions; locating an electrical contact in each contact support block such that the or each electrical shield is disposed between two adjacent electrical contacts; and locating a plurality of contact support blocks and electrical contacts within a housing, the housing defining a socket cavity.

Embodiments of the present invention will now be described, by way of nonlimiting examples only, with reference to the accompanying figures, of which: Figure 1 is perspective view of a known design for a RJ45 surfacemount socket; Figure 2 is a schematic cross-sectional illustration of a socket according to an embodiment of the present invention; Figure 3 is a perspective view of a strip of shield blanks for use in embodiments of the present invention; Figure 4 is a schematic view of a number of contact blocks over moulded on the shield blanks shown in Figure 3; Figure 5 shows enlarged perspective views of two of the contact blocks shown in Figure 4; Figure 6 shows a perspective view of a number of the contact blocks shown in Figures 4 and 5 with respective contact pins in place; and Figure 7 is a schematic view of the contact pins and shield arrangement in accordance with an embodiment of the present invention.

Figure 1 shows an illustration of a known electrical socket, in this particular instance an RJ45 socket. The socket 2 typically comprises a housing 4 that defines a cavity into which a corresponding plug, or cable terminator, can be inserted. Within the housing is located a contact block 6 that has a number of individual conductive contacts 8, the contacts typically comprising metallic strips or pins. The contacts are typically biased, either by means of additional springs or by their own inherent resilience, to bear against corresponding contacts on the plug or terminator inserted within the socket 2. Disadvantages of this known design include difficulty in adequately shielding the individual contacts to meet the requirements of some standards and a relatively complicated manufacturing and assembly procedure.

Figure 2 is a schematic illustration, in cross-section, of an electrical socket in accordance with an embodiment of the present invention. The socket 10 comprises a housing 12, which is preferably, but not necessarily, formed by conventional plastic moulding techniques. Located within the housing 12 are a series of individual contacts 14. In the particular embodiment illustrated in Figure 2 each of the contacts is formed from a resilient material and is formed with a curved portion 16. An upper portion of the contacts 14 extends into a recess 18 defined by the socket housing 12 that in use is arranged to receive a correspondingly shaped plug or connector. In use, the plug or connector received within the recess 18 forces the upper portion of the contacts 14 in a generally downward direction as shown in Figure 2 such that the angle of curvature of the contacts around their respective bent portion 16 decreases. This causes the contacts 14 to be naturally biased in an upwards direction, i.e. towards corresponding contacts on the terminal or plug located within the recess 18. This ensures a reliable electrical connection between the contacts 14 of the socket 10 and those of the corresponding plug or terminator located within the recess 18. The individual contacts 14 are mounted on corresponding individual contact blocks 20. Individual electrical shields, not shown in Figure 2, are provided in one or more of the contact blocks 20 such that as individual contacts or groups of contacts are electrically shielded from one another. The arrangement of the contact blocks and shields is described in more detail with reference to the following figures.

Figure 3 shows a perspective view of a plurality of contact shields 30 formed on a blanking strip 32 during an initial stage of the manufacture and assembly of a socket according to an embodiment of the present invention. The blanking plate 32 is preferably formed of a continuous strip of metal, or other electrically conducted material, and is subsequently passed through a stamping station that stamps out the individual contact shields 30, still connected by parts of the original continuous metallic strip. However, it will be appreciated that other known manufacturing techniques for producing strips of interconnected elements, such as the contact shields 30, can also be applied. Whilst it is preferable for the blanking strip 32 to be formed from a continuous metallic strip, discrete lengths of metallic strip may also be processed in a similar manner to produce discrete lengths of blanking strip 32, each length containing a desired number of the contact shields 30.

In a subsequent operation, insulated contact blocks 20 are formed over the contact shields 30 on the blanking strips 32 as illustrated in Figure 4. The contact blocks 20 are preferably formed from an insulating plastic and are formed over the contact shields by means of an over moulding process. In the particular embodiment shown in Figure 4, two different contact blocks 20 are formed alternatively over the contact shields 30 on the blanking strip 32. The different contact blocks 20 are provided to accommodate respective differing contact designs.

The two individual designs of contact block 20 are illustrated in Figure 5. It can be seen that each contact block 20 is generally of a rectangular shape. Each contact block 20 has a shaped recess 34 that is arranged to received individual contact pins. Each recess 34 includes a slit portion 36, which in the embodiment shown in Figure 5 is substantially linear and parallel to the longer of the two axes of the substantially rectangular contact block 20. Each slit region 36 has a height, in the orientation as shown in Figure 5, that is substantially the same as the corresponding dimension of the respective contact pin that is to be subsequently located within the recess 34. However, the depth of the slit region 36, and consequently the depth of the entire recess 34, is greater than that of the respective contact pins, such that when the contact pins are located within the recess 34 and slit portion 36, a portion of the slit portion 36 remains unfilled. On the opposite face of the contact block 20 to which the contact recess 34 is located is formed a locking protrusion 38. The locking protrusion 38 is arranged to be correspondingly dimensioned and located so as to engage in the remainder of the slit portion 36 that is left free in an adjacent contact block 20 after the respective contact pin has been located within the contact recess 34. This not only serves to hold together a series of contact blocks and contact pins after assembly, particularly if the locking protrusion 38 is arranged to be a snap fit or interference fit with the corresponding slit portion 36 of the contact recesses 34, but also ensures that the respective contact blocks 34 are assembled in a pre- determined spatial relationship to one another. An exploded perspective view of a eight separate contact blocks and respective contact pins is shown in Figure 6. To assemble the eight separate contact blocks and contact pins, it will be appreciated that the contact blocks are individually removed from the blanking strip 32 on which they are originally formed. It will also be appreciated that the number of contact block and contact pin assemblies that are to be assembled together will vary depending on the intended end use of the electrical socket.

As previously mentioned, an important element in improving the performance of electrical connectors of the kind to which embodiments of the present invention belong, is the level of electrical shielding provided between individual, or groups of, contacts. As described with reference to Figures 3 and 4, in certain embodiments of the present invention individual contact blocks 20 are formed around individual contact shields 30, such that each contact block 20 includes a contact shield 30. It is possible to provide a relatively large contact shield between individual, or groups, of contacts, as opposed to simply providing shielding directly around contacts, as is previously known in the prior art. Figure 7 schematically illustrates the arrangement of contacts and contact shields according to a further embodiment of the present invention. In the particular embodiment illustrated in Figure 7 eight contacts 114 are provided arranged in three pairs 120 of contacts flanked by two further individual contacts. The three pairs 120 of contacts and the two flanking contacts are separated from one another by individual contact shields 130. In the particular arrangement shown in Figure 7 further additional contact shields are provided adjacent the two outer contacts. It will be appreciated that the particular arrangement of contacts and shields shown in Figure 7 can be provided by increasing the spacing between individual contact shields 30 on the blanking strip 32 at the time of manufacture of the blanking strip, such that during the over moulding process one or more contact blocks are formed that have no internal contact shield. This allows the adjacent placing of two or more contact pins without intervening contact shield as illustrated in Figure 7. It will also be appreciated that although the shields are illustrated in the accompanying figures as being substantial flat plates they may equally include one or more stepped portions.

In other words each shield may comprise a number of discrete substantially planar portions, the portions lying in different planes to one another, with stepped, or joggled', transitions between the planar portions. Furthermore, where multiple shields are employed within a single socket there is no necessity for the shields to be parallel.

As already indicated above, the manufacture and assembly steps for a socket according to embodiments of the present invention is as follows the contact shields are formed in strip form using an appropriate stamping, possibly moulding, process. The contact shields may be produced in this fashion either as a continuous strip or as discrete strips containing a number of individual contact shields. The strips of contact shields are then over moulded to form strips of individual contact blocks. The individual contact blocks are subsequently separated from the carrier strips. Respectively shaped contact pins are located within correspondingly shaped recesses within the individual contact blocks and the appropriate number of contact blocks are subsequently clipped or fastened together to form an intermediate contact assembly. The intermediate contact assembly is then located within a socket housing. The contact pins preferably manufactured on a bandelier in a known manner. This allows the contact pins to be subsequently coated over selected portions thereof. The coating process is desirable if the contact pins are manufactured from a material having the desired mechanical properties, such as strength and resilience, but having less than idea electrical properties. For example, the contacts may be manufactured from a steel strip or suitable copper alloy. It is therefore desirable to coat at least a portion of the contact pins with a further material having the more desirable conductive properties, for example gold over palladium plating. By forming the pins as a bandelier it is possible to only coat those portions of the contact pins that are likely to be brought into contact with the corresponding contacts of a connector or plug that will be inserted within the finished socket. This means that only a minimum of plating material is required, thus reducing costs.

Although the embodiments of the present invention described above with reference to the accompanying figures relate primarily to an RJ45 socket, it will be appreciated that invention is no way limited to any particular type of socket or connector that may be applied to many other socket and connector types.

Claims

1. A shielded socket assembly comprising a plurality of electrical contacts and at least one electrical shield disposed between two adjacent electrical contacts, the shield comprising one or more substantially planar portions.

2. A shielded socket assembly according to claim 1, wherein each of the plurality of electrical contacts is in engagement with a contact support block.

3. A shielded socket assembly according to claim 2, wherein the or each electrical shield is supported by a respective contact support block.

4. A shielded socket assembly according to claim 3, wherein the or each electrical shield is enclosed by the respective contact support block.

5. A shielded socket assembly according to claim 2, 3 or 4, wherein each contact support block is arranged to be fastened to an adjacent contact support block.

6. A shielded socket assembly according to claim 5, wherein each contact support block has a pair of opposing faces, one of the opposing faces having a shaped protrusion formed thereon and the other opposing face having a correspondingly shaped recess formed therein, the shaped protrusion and recess being located such that, in use, the shaped protrusion of a first contact support block is engaged within the correspondingly shaped recess of a second contact support block, thereby forming a snap or interference fit between the first and second contact support blocks.

7. A shielded socket assembly according to any preceding claim, wherein said contacts and electrical shield are located within a housing, the housing defining a female connector arranged to receive a corresponding male connector.

8. A method of manufacture of a shielded socket assembly, the method comprising: forming a plurality of contact support blocks, at least one of which comprises an electrical shield having one or more substantially planar portions; locating an electrical contact in each contact support block such that the or each electrical shield is disposed between adjacent electrical contacts; and locating a plurality of contact support blocks and electrical contacts within a housing, the housing defining a socket cavity.

9. The method of claim 8, wherein the step of forming the plurality of contact support blocks comprises: forming a plurality of electrical shields on a carrier strip; and over moulding the contact support blocks on the carrier strip such that at least one contact support block is over moulded on one of the electrical shields.

10. The method of claim 8 or 9, wherein each contact support block is arranged to be fastened to an adjacent contact support block.

11. The method of claim 10, wherein each contact support block has a pair of opposing faces, one of the opposing faces having a shaped protrusion formed thereon and the other opposing face having a correspondingly shaped recess formed therein, the shaped protrusion and recess being located such that, in use, the shaped protrusion of a first contact support block is engaged within the correspondingly shaped recess of a second contact support block, thereby forming a snap or interference fit between the first and second contact support blocks.

12. The method of any one of claims 9 to 11, wherein the step of forming the plurality of electrical shields comprises stamping said shields and interconnecting portions from a strip of conductive material.

13. The method of any preceding claim comprising providing a plurality of elongate electrical contacts and coating a portion of the contacts with an electrically conductive material.

14. The method of claim 13, wherein the elongate material contacts are formed by stamping a strip of material.