GB2222917A

GB2222917A - Electrical connector for PCB

Info

Publication number: GB2222917A
Application number: GB8918043A
Authority: GB
Inventors: John Covell Collier; Keith Davies
Original assignee: ITT Industries Ltd
Current assignee: ITT Industries Ltd
Priority date: 1988-08-16
Filing date: 1989-08-07
Publication date: 1990-03-21
Also published as: FR2635614A1; GB8819435D0; DE4000407A1; DE3926802A1; GB8918043D0; JPH02168581A

Description

1 1 1 C:.

1 J.C.Collier 15-6X 2222917 ELECTRICAL CONNECTOR This invention relates to electrical connectors, and in particular to electrical connectors for surface mounting onto a printed circuit board.

It is known to provide an electrical connector with a plurality of electrical contacts for surface mounting onto a printed circuit board. The contacts may be vapour phase soldered onto the PCB, or alternatively may penetrate the coating of the PCB, as in U.S. Patent No.2853382 to Burndy Corporation.

The present invention seeks to provide an improvement to the prior art connectors described above.

It is also known to provide an electrical connector having several rows of pins for example three rows of 32 pins for mounting on a printed circuit board by insertion through a similar configuration of rows of holes the pins being electrically connected to printed circuit tracks on the board by for example soldering.

Yet another arrangement known to us for use with multilayer printed circuit boards to mount a multirow multipin connector is to employ resilient pins which are a press fit into respective holes and which thereby both retain the electrical connector on the board and make electrical connection thereto.

With the advent of more complex circuitry printed circuit layout becomes difficult if there are numerous holes through the board which have to be avoided by the printed 1 1 2 circuit tracks.

The present invention has been arrived at from a consideration of this problem with multipin connectors but is equally applicable to simpler connectors employing two or 5 more pins.

Accordingly, there is provided an electrical connector for a printed circuit board, the connector comprising an insulating housing; and a plurality of electrical contacts received within the housing, at least one of the electrical contacts being adapted to form a press fit connection within a plated through hole of a printed circuit board, and at least one other of the electrical contacts being adapted to form a high pressure connection with the surface of a printed circuit board.

Preferably the at least one other of the electrical contacts which is adapted to form a high pressure connection includes a sharp edged region capable of establishing a low resistance electrical connection with a contact region on a printed circuit board, the contact region being formed of a ductile metallic material, the sharp edged region penetrating and deforming the ductile metallic material of the contact region. In this way, there is no need for the re-flow soldering of the electrical connector to the printed circuit board. The soldering process can therefore be eliminated or, where it is required for other components on the circuit board, the connector can be installed after the re-flow soldering process.

There is preferably provided at least one row of electrical contacts adapted to form a high pressure connection with the surface of a printed circuit board. Additionaly, there is conveniently provided at least one row of electrical contacts adapted to form a press fit connection within plated through holes of a printed circuit board. In a preferred construction, there is provided three rows of electrical contacts, two rows of electrical contacts adapted to form a high pressure connection with the surface of a printed circuit board, and one row of electrical 1 p 1 3 contacts adapted to form a press fit connection within plated through holes of a printed circuit board. Conveniently, the one row of electrical contacts adapted to form a press fit connection is located between the two rows of electrical contacts adapted to f orm a high pressure connection.

It has been found that the press fit contacts serve to retain the electrical connector on the PCB, and maintain the necessary contact pressure for the high pressure contacts.

In addition, by employing a plurality of press f it contacts, the tendency for the printed circuit board to bow due to the force generated by the high pressure contacts can be counteracted.

It is not necessary for there to be equal numbers of contacts in the rows of press f it contacts and high pressure contacts. For example, it may be found that a smaller number of press fit contacts is sufficient to maintain contact pressure and prevent bowing of the printed circuit board. For multi-layer circuit boards, a larger number of rows of contacts may be necessary. One type of connector according to the invention includes five rows of electrical contacts, nameley four rows of high pressure contacts and a central row of press fit contacts. In an alternative construction there is provided a connector with a single row of electrical contacts with press fit contacts interspersed amongst high pressure contacts.

In order that the invention and its various other preferred features may be unders tood more easily, some embodiments thereof will now be described, by way of example only, with reference to the drawings in which Figure 1 is a cross sectional view taken through a three row pin connector constructed in accordance with the invention, Figure 2 is a detail showing an alternative sharp edge contact suitable for use with the construction of Figure 1, and Figure 3 is a cross sectional view of a four row 4 connector constructed in accordance with the invention. - The pin connector of Figure 1 comprises a plastics housing 10 having an open top for receiving a mating socket connector. The housing has three rows of Pin contacts 111 12, 13 which are moulded in and extend through the base of the housing. The pins 12 extend straight through the housing and have an enlargement 14 near their remote ends beyond the base of the housing which permits secure press f it connection with a row of plated through holes 15 in a printed circuit board 16. The pins 11 & 13 have resilient ends 16. 17 which are bent and extend outwardly beyond the sides of the housing the extremities of which ends are radiused to provide a convex contact surface 19,20 facing downwardly from the base. High pressure contact of the contact surfaces 18 and 19 with tracks 18, 19 on the surface of the printed circuit board is made when the connector is secured to the board by press insertion of the pins 12 in the plated through holes 15. in normal circumstances the electrical contact made by the high pressure contact will be excellent and connection to the board can be effected after other components have been mounted. However, solder paste can be provided on the track and soldering can also be effected during a reflow soldering operation if required.

Figure 2 shows an alternative configuration for the extremity of the contacts 11 and 13 of Figure 1. Instead of providing a radiused extremity a sharp edge is employed. Upon insertion of the pins 12 into the plated through holes the sharp edge 24 is forced into and deforms ductile metal plating on the track to ensure good electrically conductive connection thereto.

Figure 3 shows a four row electrical pin connector in which the outer rows have pins 31 similar to the pins 11 & 13 of Figure 1 but with the sharp edge contact of Figure 2 and the inner rows have press fit pins 32 with enlargements 34 similar to the pins 12 of Figure 1.

Although the pins 12, 32 are shown to have bulbous enlargement 14, 34 any formation which permits press or 1 driven in secure contact can be employed for example the pin may be tapered, ridged or serated. The end may have a transverse aperture there through similar to the eye of a needle to enhance the resilience of the pin to facilitate 5 pressing or driving into the plated through holes.

Although the constructions described employ rows each having the same type of pin i.e. straight or bent it should be appreciated that the types can be mixed in one or more rows. For example in the construction of Figure 1 every fifth pin may be a straight pin and the remainder bent pins. Such a construction results in a further reduction of the number of holes through the board and facilitates laying out of the printed circuit tracks during the design stage as there are fewer holes which have to be avoided by the track.

A single or any number of rows of pins can be employed and in the simplest case a two pin connector can be constructed employing the principles of the invention.

Although the connector described employs pin contacts it should be appreciated that socket contacts of similar configuration can be employed or a mixture of pin and socket contacts may be provided. Such constructions are considered to fall within the scope of this invention.

6

Claims

1. An electrical connector for a printed circuit board, the connector comprising an insulating housing; and a plurality of electrical contacts received within the housing, characterised in that at least one of the electrical contacts is adapted to form a press fit connection with a plated through hole of a printed circuit board, and at least one other of the electrical contacts is adapted to form a high pressure connection with the surface of a printed circuit board.

2. An electrical connector as claimed in claim 1, characterised in that the at least one other of the electrical contacts which is adapted to form a high pressure connection has a radiused end providing a convex surface capable of establishing electrical connection with a contact region on a printed circuit board.

3. An electrical connector as claimed in claim characterised in that the at least one other of the electrical contacts which is adapted to form a high pressure connection includes a sharp edged region capable of establishing a low resistance electrical connection with a contact region on a printed circuit board, the contact region is formed of a ductile metallic material, the sharp edged region penetrating and deforming the ductile metallic material of the contact region.

4. An electrical connector as claimed in any one of claims 1 to 3, characterised in that there is provided at least one row of electrical contacts adapted to form a high pressure connection with the surface of a printed circuit board.

5. An electrical connector as claimed in claim 4, characterised in that there is provided at least one row of electrical contacts adapted to form a press fit connection 35- with plated through holes of a printed circuit board.

6. An electrical connector as claimed in claim 5, characterised in that there is provided three rows of 7 electrical contacts, two,rows of electrical contacts adapted to form a high pressure connection with the surface of a printed circuit board, and one row of electrical contacts adapted to form a press fit connection within plated through 5 holes of a printed circuit board.

7. An electrical connector as claimed in claim 5, character in that the one row of electrical contacts adapted to form a press fit connection is located between the two rows of electrical contacts adapted to form a high pressure connection.

8. An electrical, connector as claimed in claim 4, characterised in that there is provided at least one row of contacts including contacts adapted to form a high pressure connection with the surface of a printed circuit board and contacts adapted to form a press fit connection with plated through holes of a printed circuit board.

9. An electrical connector substantially as described herein with reference to the drawings.

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