A plug and socket connector

Abstract: A plug and socket connector comprises a plug portion (12) with contact elements (22), a socket portion (10) with contact elements (14) and a supporting member (18) of electrically insulating material. The contact elements of each portion form at least elongated spaced apart row and the arrangement is such that, when the plug and socket portions are in mating relationship, the contact elements of one portion are in electrical contact with the contact elements of the other portions. The contact elements (14) of the socket portion (10) are so disposed and arranged as to be capable of mating in electrical contact with a plug portion with one half the number of contact elements of the socket portion.

Description: This invention relates to plug and socket connectors. In view of the continuously progressive miniaturization of apparatus and components in electrical communications and transmission engineering, the construction of plug and socket connectors becomes of constantly increasing importance, particularly with respect to increasing the number of electrical connections while maintaining or reducing the physical dimensions of the connector. A typical plug and socket connector for printed circuit boards is of the D-shape type which provides the proper orientation of a plug portion into a socket portion. An example of an electrical connector of this type is shown in US-A-3500295 in which a plug and socket connector adapted for use on printed circuit boards is described. As printed circuit boards become more complex embodying multiple layers within a board, the multiplicity of connections needed for communication with the printed circuit board increase while the area available on the board for placement of components and connectors is reduced. Typical D-shaped connectors are of a small size and are called sub-miniature D-shaped electrical connectors. These connectors carry up to a maximum of 50 electrical contacts. For electrical communication between computer equipment and peripheral devices a communications bus protocol is needed. One such protocol authorised by the American National Standards Institute (ANSI) is the Small Computer Systems Interface (SCSI). There is a growing interest within the industry for a connector that can provide more than one byte wide SCSI bus while remaining within the same form factor or physical dimensions of an existing sub-miniature D-shaped 50-pin connector. It is desirable to maintain both upward and downward compatability between connectors of existing and new designs. The present invention seeks to provide a plug and socket connector suitable for carrying more than one byte wide SCSI bus while retaining the form factor of conventional sub-miniature D-shaped 50-pin connectors. The plug and socket connector according to the present invention may possess the physical outer dimensions of a conventional sub-miniature D-shaped 50-pin connector whilst doubling the number of electrical contacts made within the same spacing. According to the present invention there is provided a plug connector for providing an electrical connection to a socket connector of the same form factor, said plug connector comprising: a plurality of plug contacts; an elongated supporting member of electrically insulating material for supporting each plug contact; each plug contact providing electrical connection to a corresponding one of a plurality of socket contacts of said socket connector, characterised in that each plug contact is disposed in half the linear spacing occupied by each socket contact in the elongated direction thereby providing electrical connection between each socket contact and one or two plug contacts. Also there is provided a socket connector for providing an electrical connection to a plug connector of the same form factor, said socket connector comprising: a plurality of socket contacts; an elongated supporting member of electrical insulating material for supporting each socket contact; each socket contact providing electrical connection to a corresponding one of a plurality of plug contacts of said plug connector; characterised in that each socket contact is disposed in half the linear spacing occupied by each plug contact in the elongated direction thereby providing electrical connection between each plug contact and one or two socket contacts. The contact elements of the plug portion may be arranged in staggered rows. Alternate contact elements of the plug portion may be of L-shape. The supporting member preferably does not support an outer row of the contact elements of the plug portion. The connector may have a housing for supporting the supporting member, said housing being D-shaped in plan. The supporting member of the socket portion preferably has relatively large spacer portions between alternate contact elements and relatively small spacer portions between the remainder of the contact elements. Each of the plug and socket portions may have 100 contact elements. The invention as illustrated, merely by way of example, in the accompanying drawings, in which:- Figure 1 is an isometric view of a D-sub-miniature plug and socket connector; Figure 2a is a sectional view of a socket portion of a conventional plug and socket connector; Figure 2b is a sectional view of a socket portion of a plug and socket connector according to the present invention; Figure 3a is a top view of a plug portion of a conventional plug and socket connector; Figure 3b is a top view of a plug portion of a plug and socket connector according to the present invention; Figure 3c is a top view showing an alternative embodiment of a plug portion of a plug and socket connector according to the present invention; Figure 4a is a bottom view of a socket portion of a conventional plug and socket connector; Figure 4b is a bottom view of a socket portion of a plug and socket connector according to the present invention; Figure 5 is a sectional end view of a plug and socket connector according to the present invention; Figure 6a is a partial sectional view of a mated plug portion of a conventional plug and socket connector with a socket portion of a plug and socket connector according to the present invention; and Figure 6b shows mating plug and socket portions of a plug and socket connector according to the present invention. Shown in Figure 1 is a conventional D-shaped sub-miniature plug and socket connector. A socket portion 10 is a unitary body and can be made of, for example, steel with zinc plating. Likewise, a plug portion 12 is of one piece construction and is designed to engage with the socket portion 10. A metallic housing, D-shaped in the plan, forms the support structure for each of the plug and socket portions. Electrical contacts 14 are spaced along the length of the socket portion and can be made of a base material of beryllium copper and can have a plating of nickel-gold to decrease electrical resistance across a contact junction. A support 18 of an electrically insulating thermoplastic material such as, for example, a polymer, provides for dielectric separation between the housing of the socket portion 10 and the contacts 14. An electrical connection can be made to the electrical contacts 14 through wires 16 which are designed to mount directly to a printed circuit (PC) board. Alternatively, the socket portion 10 can connect to an electrical wire connections rather than a PC board. The plug portion 12 of the connector has posts 22 which are designed to connect an electrical wire cable such as a ribbon cable or a discrete wire bundle. The posts feed through to the electrical contacts 14 in the plug portion. The electrical wire cable can be 50 pairs of 28 guage wire forming a bundle of approximately 1.3cm (0.5 inch) diameter and desirably highly flexible. Such cables are available from Madison Cable, 125 Goddard Memorial Drive, Worcester, MA 01603, U.S.A. Holes 20 can be used to attach the plug portion to the socket portion or for attachment to a PC board. A bail type latch (not shown) may also be employed on the connector. In a plug and socket connector according to the present invention two electrical contacts 14 are placed within the same linear spacing as one contact of the plug and socket connector of Figure 1. As shown in Figure 2a to maintain the lateral separation between adjacent electrical contacts 14 in the plug and socket connector of Figure 1, a spacer 30 forming integral part of the support 18 is placed therebetween. As shown in Figure 2b spacers 32, also forming an integral part of the support 18, and are positioned between narrower electrical contacts 14 of the 100-pin plug and socket connector according to the present invention. These spacers 32 do not extend as far as the larger spacers 30 of the plug and socket connector as shown in Figure 2a. Therefore, electrical connection can, for example, be made between a 50-pin plug portion as shown in Figure 3a mating with a 100-pin socket portion of the plug and socket connector according to the present invention as shown in Figure 2b. Making effective electrical connection to a plug portion of a plug and socket connector can be very difficult. Whether using a ribbon cable or a discrete wire bundle, it is often desirable to connect the cable to the posts 22 of the plug portion without the use of solder. Due to the increased number of contacts necessary to be made to a plug portion of a plug and socket connector according to the present invention, a staggered arrangement as shown in Figure 3b is used. This arrangement is in contrast with straight line arrangement (Figure 3a) of the plug portion 12 of the plug and socket connector shown in Figure 1. The posts 22 may have widened areas for crimping onto electrical wires. The support 18 separates each post. An alternative embodiment of a plug portion of a plug and socket connector according to the present invention is shown in Figure 3(c) where no portion of the support 18 is used to separate the posts 22, separation being provided by the staggered relationship of adjacent posts. This provides easy access to the posts for crimping electrical wires thereto. In the cross sectional view of Figure 4a which is taken looking upwards, the plug portion of the 50-pin plug and socket connector of Figure 1 is contrasted with the plug portion of a 100-pin connector according to the present invention which is shown in Figure 4b. As seen in Figure 4a, the electrical contacts 14 are separated by the spacers 30 which extend outwards nearly as far as the contacts. In Figure 4b, each pair of electrical contacts 14 are separated by larger spacers 30 which protrude outwards from the centre of the plug portion nearly as far as the electrical contacts while each individual contact is separated by a smaller spacer 32 of the support 18. The smaller spacers 32 do not extend from the centre line of the plug portion as far as the larger spacers 30. Thus a 100-pin plug portion of a 100-pin plug and socket connector according to the present invention can mate with the socket portion of a 50-pin plug and socket connector as shown in Figure 1. A cross sectional view of an unmated plug and socket connector according to the present invention is shown in Figure 5. The socket portion 10 contains electrical contacts 14 and electrical wires 16 having a dielectrical encasement of the support 18. The plug portion 12 has posts 22, 23 leading in through the support 18 as shown. It can be seen that each post 22 is L-shape, where as each post 23 is straight. This is because of the staggered configuration of the electrical contacts 14 on the plug portion. Alternate posts will be L-shaped. It is desirable that the posts can be easily located into the plug portion by conventional means to promote ease of manufacture of the plug and socket connector. Figure 6a shows a plug portion of the 50-pin plug and socket connector of Figure 1 mated to a socket portion of a 100-pin plug and socket connector according to the present invention. The electrical contacts 14 mate together being laterally separated by the larger spacer 30. On the socket portion the smaller spacers 32 separate each electrical contact whilst the larger spacers 30 separate each pair of electrical contacts 14. Figure 6b shows a plug portion and a socket portion of a 100 pin plug and socket connector according to the present invention. The electrical contact 14 of the plug portion mate directly opposite to the electrical contacts 14 of the socket portion with the larger spacers 30 and the smaller spacers 32 separating the contacts 14. The plug and socket connector according to the present invention as described above provides compatibility between 100-pin plug or socket portion and a 50-pin socket or plug portion thereby satisfying the ANSI requirements for downward and upward compatibility of electrical components. Some of the 100-pin connectors can be used to determine whether a 100-pin plug portion is mating with another 100-pin socket portion or mating only with a 50-pin socket portion.

Claims: A plug connector (12) for providing an electrical connection to a socket connector (10) of the same form factor, said plug connector comprising: a plurality of plug contacts (22); an elongated supporting member (18) of electrically insulating material for supporting each plug contact; each plug contact providing electrical connection to a corresponding one of a plurality of socket contacts (14) of said socket connector, characterised in that each plug contact is disposed in half the linear spacing occupied by each socket contact in the elongated direction thereby providing electrical connection between each socket contact and one or two plug contacts. A socket connector (10) for providing an electrical connection to a plug connector of the same form factor, said socket connector comprising: a plurality of socket contacts (14); an elongated supporting member (18) of electrical insulating material for supporting each socket contact; each socket contact providing electrical connection to a corresponding one of a plurality of plug contacts (22) of said plug connector; characterised in that each socket contact is disposed in half the linear spacing occupied by each plug contact in the elongated direction thereby providing electrical connection between each plug contact and one or two socket contacts. A plug connector as claimed in claim 1, in which the plug contacts (22) are arranged in staggered rows. A plug connector as claimed in claim 3 in which alternate plug contacts are L-shaped. A plug connector as claimed in claim 3 or 4, in which the supporting member (18) does not support an outer row of plug contacts. A socket connector as claimed in claim 2, in which the supporting member (18) has relatively large spacers (30) between alternate socket contacts and relatively smaller spacers (32) between the remainder of the socket contacts. An arrangement comprising a plug connector as claimed in any one of claims 1, 3 4 or 5 and a socket connector as claimed in claim 2 or 6. An arrangement as claimed in claim 7, in which said form factor of said plug connector and said socket connector is D-shaped. An arrangement as claimed in claim 8, in which the claimed plug and socket connector each comprise 100 contacts.

Inventors: LIDHOLM ROBERT ALLEN, MILLER MICHAEL ALAN, LIDHOLM, ROBERT, ALLEN, MILLER, MICHAEL ALAN
Applicants: SEAGATE TECHNOLOGY, SEAGATE TECHNOLOGY INTERNATIONAL
Application year: 1988
Main classification: H01R27
IPC codes: H01R27, H01R12