Connector Device With Integral Reference Plane

Abstract

A connector having a hollow elongated casing of an electrically connecting material. A bulkhead, formed as part of the casing, is positioned across the hollow opening. There are a plurality of holes formed in the bulkhead each of which has a spring clip of electrically conducting material mounted therein in electrical contact with the bulkhead. Pin means, which are adapted to pass through the holes, each have included as a part thereof an electrical filter having an outer surface of conductive material. The filters are dimensioned to cause the outer surface to be in electrical contact with the corresponding clip when the pin is properly positioned in the corresponding hole.

Description

This invention relates to a connector device which contains an integral reference plane for applying a reference potential to an electrical filter utilized as part of the connector.

In order to prevent noise from passing from one electrical element to another through the connector joining them, connectors have recently been designed which include, as part of each connector pin, a filter element which is adapted to pass only signals at the desired frequency. The filters generally utilized for this purpose have an electrically conducting outer shell which serves as one terminal of the element. In order for the filter element to operate satisfactorily, a good low-impedance electrical connection must be made between this shell and a source of a reference voltage level such as ground.

In existing connectors of this type, the casing of the connector is established as a ground reference and a bulkhead is inserted into this hollow casing and secured in place by spring clips. The spring clips are of electrically conducting material and, since they contact both the casing and the bulkhead, they serve to apply a ground potential to the bulkhead. The bulkhead has a plurality of openings through which the pins containing the filters are passed. Spring clips mounted in each of these openings serve to apply the desired ground potential to the shell of each of the filters. Existing connectors have also applied ground potential to the bulkhead by substituting a solder joint for the spring clips or by pressure fitting the bulkhead into the connectors.

The connector described above thus requires at least two electrical connections in order to obtain the desired potential at the shell of the filter. Each of these connections increases the impedance between ground and the filter shell and also serves as a possible source of discontinuity in the electrical path. The assembly of such a connector is also relatively complex involving delicate operations both in the insertion of the springs in the casing and in the positioning of the bulkhead. The space between the casing and the bulkhead also provides another opening through which electromagnetic interference (EMI) leakage may occur. It is thus apparent that, if the number of contacts required to apply ground potential to the shell of the filter could be reduced, an improved filter connector would be obtained.

It is thus a primary object of this invention to provide an improved reference plane configuration for an electrical connector.

More specifically, it is an object of this invention to provide an improved means for applying the reference potential to the outer shell of a filter element in a filter connector.

A still more specific object of this invention is to provide a means for reducing the number of electrical contacts required to obtain a reference potential in a connector of the type described above.

In accordance with these objects this invention provides a connector device having a hollow elongated casing of an electrically conducting material. A bulkhead formed as an integral part of the casing is positioned to block the hollow opening in the casing and has a plurality of holes formed in it. A spring clip of electrically conducting material is mounted in each of the holes in a manner such that it makes electrical contact with the bulkhead. Pin means, each of which includes as a part thereof a filter having an outer surface of conductive material, are adapted to pass through each of the holes. Each of the filters is dimensioned so as to cause its outer surface to be in electrical contact with the corresponding clip when the pin means is properly positioned in a hole. With this arrangement it is possible to apply the desired reference potential to a point on the skin of each filter through only a single electrical contact.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention as illustrated in the accompanying drawing.

The single FIGURE is a partially cutaway diagram of a preferred embodiment of the invention.

Referring now to the FIGURE it is seen that the connector in the preferred embodiment of the invention is made up of two sections, a casing 10 and a locking insert 12. The casing 10 is forged of an electrically conducting metallic material such as an aluminum. It includes a flange 14 for the securing the connector to some external member, an external screw thread 16 for securing a plug or female connector to the connector, an internal screw thread 18 for securing the locking insert 12 to the casing 10, and a bulkhead 20 which forms a barrier across the connector interior. Bulkhead 20 is forged as an integral part of casing 10. A plurality of holes 22 are drilled in bulkhead 20 and spring clips 24 are pressed into each of these holes. The compression of the fingers of each clip which is required to press it into the hole 22 assures a tight pressure fit which holds the clip in place. The clip is prevented from moving forward through hole 22 by flange 26 on its rear edge and is prevented from moving backward by a hard dielectric insert 28 which is secured in the opening of casing 10 behind bulkhead 20. It may be explained that in the connector art the portion of the connector that joins with the mating connector is referred to as the "forward" face, while the opposite ends, remote from each other in the completed assembly, are referred to as "rearward" faces. A resilient grommet 30 which may, for example, be a rubber insert, is secured in the opening of casing 10 in front of bulkhead 20. Elements 28 and 30 each has a plurality of holes formed therein which holes correspond in number to the holes 22 in bulkhead 20 and are aligned therewith. The rear of each of the holes 32 in insert 28 is slightly tapered for reasons which will be described shortly.

Referring now to locking insert 12, it is seen that it includes an outer shell 40 having an external thread 42 which is adapted to coact with the thread 18 to advance and retract the plug in casing 10. Shell 40 is rolled over to form a flange 44 which is adapted to ride in track 46 of retaining insert 50. Insert 50 is of an insulating material such as plastic. Flange 44 secures shell 40 to insert 50 while permitting rotation between these two members. Insert 50 has a plurality of holes 52 formed therethrough which holes correspond in number to the holes 22 and each of which is adapted to contain a pin means 54. The forward portion of insert 50 has a slightly extending projection 56 in the area of each of the holes 52. The function of these projections will be described shortly. Each of the pins 54 includes as part thereof a low-pass filter element 58. These filter elements are of a standard type available from a variety of manufacturers. As was indicated previously, the outer shell of each filter 58 is of conductive material and serves as one terminal of the device. An electrical signal is applied to a pin 54 through wire 60 which is secured to the pin in a standard fashion. The final element of plug 12 is resilient grommet 62.

From the FIGURE it is seen that when the connector is assembled, thread 18 mates with thread 42 and pin 54 passed through openings 22, 32 and 34 in bulkhead 20, insert 28, and grommet 30 respectively. Insert 12 may be captivated in casing 10 by standard means such as a spin or form over the last thread of the casing thread 18. When insert 12 is in a retracted position, projections 54 are outside of opening 32 and pin 54 may be easily removed from insert 12. However, when casing 40 of insert 12 is rotated to advance the insert to the position shown in the FIGURE, projections 54 are wedged into opening 32 thereby securing the pins in place. A more detailed description of this manner of securing pins or like elements is provided in copending application, SER. No. 558,958, now U.S. Pat. No. 3,477,061, entitled "Contact Retention Device," filed June 20, 1966 on behalf of C. Dean Stephenson and assigned to the assignee of the instant application.

From the FIGURE it is also seen that only a single electric contact is required in order to apply the desired reference potential to a point on the shell of filter 58. This contact is effected through spring clip 24. It should be noted that each finger of this clip has two points of electrical contact with the bulkhead. Existing connectors have only a single point of contact. This extra contact point is obtained by increasing the width of bulkhead 20 and by increasing the angle of the bend at the end of the clip finger.

Casing 10 may be made from an aluminum impact blank which is impact forged within a die through the use of a high-pressure press. Holes 22 may then be drilled in bulkhead 20 to complete the operation. The desired ground plane may thus be secured in a simple and inexpensive manner.

While on the preferred embodiment of the invention illustrated in the FIGURE, casing 10 has served as part of the male portion of the connector, casing 10 could serve as the female portion of the connector if suitable elements are provided in casing 10 to make electrical contact with the far end of pins 54, and if other minor modifications were made in the elements 10 and 12. Thus, it is equally within the contemplation of this invention to secure the reference level for filters 58 from the male or female portion of the connector. Similarly, while the invention has been shown and described with filter elements in the pins 54, the invention would be equally applicable in any situation where pins 54 contain electrical elements which require that a reference potential be applied to this outer shell.

Thus, while the invention has been particularly shown and described with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details may be made therein without departing from the spirit and scope of the invention.

Claims

What I claim is:

1. A filter connector comprising in combination, a hollow casing of an electrically conducting material having forward and rearward face surfaces with at least one cavity at each of said opposite face surfaces thereof; an electrically conductive bulkhead forming an integral part of said casing, said bulkhead being positioned transversely between the cavities in said casing; and a plurality of holes formed in said bulkhead; elongated electrical contacts in at least some of said holes, said contacts each having a telescoping forward portion for engagement with a mating contact, a rearward terminal portion adapted for attachment to a flexible conductor, and an intermediate portion comprising an electrical filter assembly; with an annular groove around the contact between the rearward terminal portion and the filter assembly thereof, and contact retention means positioned wholly within the cavity at the rearward face of the casing and spaced rearwardly from the bulkhead thereof; the filter assembly including a smooth cylindrical exterior conductive surface extending forwardly from said annular groove through the transverse metal bulkhead of the casing, with a spring clip of thin, resilient electrically conducting material mounted within each of said holes in said bulkhead; each of said clips being in surface-to-surface pressure engagement with both the exterior conductive surface of the contact pin filter and with the internal surfaces of a hole in the connector casing bulkhead to establish intimate electrical contact between the exterior surface of the filter and said bulkhead to ground the exterior conductive surface of the filter to the connector casing.

2. A filter connector according to claim 1 wherein the spring clips defined therein have an annular flange bearing against only the rearward surface of the transverse bulkhead to restrain the clips against forward displacement, yet permit individual removal of any individual contact and filter or spring clip without displacement of others.