Electrical Connector Shield

Abstract

A radio frequency and electromagnetic interference shield for an electrical connector comprising a helically coiled conductive spring which is interposed between facing surfaces on the mating halves of the connector. The spring is coiled in such a manner that the convolutions thereof are slanted at an oblique angle to the center axis of the connector members. The axial distance between said facing surfaces when the connector members are mated is less than the normal outside helical diameter of the convolutions of the spring. Thus, mating of the connector members axially flattens the spring to form an almost continuous metal shield between the connector members.

Description

BACKGROUND OF THE INVENTION

The present invention relates generally to a shielding member and, more particularly, to a radio frequency and electromagnetic interference shielding member for an electrical connector.

The use of shielding in electrical connectors to eliminate unwanted radio frequency and electromagentic interference from interfering with signals being carried by contacts in connectors is well known. Typically, multifinger strip contacts are soldered, crimped or spot welded in place. Alternatively, closed loop preforms have been used as shields but have been relatively expensive and cannot be easily installed in a connector. Another form of a connector shield is disclosed in U.S. Pat. No. 3,678,445. This shield has the advantage over the previous mentioned shields in that it may be installed on a connector with a simple snap-in operation. Thus, no bonding or intermediate joining processes are required. However, such shield embodies spring fingers which are subject to breakage and fragmentation when exposed to extreme deflection or other abuse.

Therefore, what is desired is a shield which not only may be easily installed on a connector but is also relatively immune to damage when subjected to extreme operating conditions.

SUMMARY OF THE INVENTION

The principal object of the present invention is to provide a radio frequency and electromagentic interference shield for an electrical connector which may be easily installed on a connector and is relatively rugged.

According to the principal aspect of the present invention, there is provided a shield which is interposed between facing surfaces of the mating halves of an electrical connector. The shield comprises a helically coiled conductive spring which is coiled in such a manner that the convolutions of the spring are slanted at an oblique angle to the center axis of the connector members. The axial distance between the facing surfaces when the connector members are mated is less than the normal outside helical diameter of the convolutions of the spring. Thus, when the connector halves are mated, the spring is axially flattened to provide an almost continuous metal shield between the mating halves. The coil spring provides excellent shielding against RFI (radio frequency interference) and EMI (electromagnetic interference). Because of the slant design of the spring convolutions, a wiping action between the spring and the facing surfaces on the connector halves takes place when the halves are mated. This wiping action assures positive electrical continuity and thus an effective grounding of the respective connector halves. The shielding spring of the present invention is easily installed on a connector, is inexpensive and rugged. Also, because the spring is flexible, it may be adapted to many shapes of connector bodies.

Other aspects and advantages of the invention will become more apparent when the following description taken in connection with the accompanying drawing.

A BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a partial longitudinal sectional view of an electrical connector embodying the shielding spring of the present invention, with the convolutions of the springs being shown in their normal relaxed condition before the connector halves are fully mated;

FIG. 2 is a top plan view of the shielding spring of the present invention.

FIG. 3 is a transverse sectional view taken generally along line 3--3 in FIG. 1 showing a side view of the shielding spring in its normal relaxed condition and

FIG. 4 is a sectional view similar to FIG. 3 showing the shielding spring flattened after the mating halves of the connector have been fully mated.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawing in detail, there is shown in FIG. 1 the connector of the present invention, generally designated 10, comprising a plug connector member 12 and a receptacle connector member 14. The plug connector member 12 comprises a cylindrical barrel 16 which is telescopically positioned in the front end of the cylindrical shell 18 of the receptacle connector member. A plurality of socket contacts 20 are axially positioned in insulators 22 and 24 mounted in the barrel 16, only one such contacts being illustrated in FIG. 1. Each socket contact 20 receives a pin contact 26 which is mounted in an insulator 28 in the receptacle connector member 14. A facing seal 30 may be provided on the front face of the insulator 28.

A coupling nut 32 is mounted on the barrel 16. The forward end of the nut surrounds the receptacle shell 18. An integral outwardly extending flange 34 is formed on the barrel 16. An annular member 36 is retained in the coupling nut 32 by a retaining ring 38. A wave spring 40 is interposed between the flange 34 and the annular member 36 to bias the coupling nut 32 in the rearward direction.

One or more projections 42 are mounted in the receptacle shell 18. Each projection is slidably received in a corresponding internal helical groove 44 havings its entrance at the end surface 46 of the coupling nut 32. The barrel 16 and shell 18 have a key-keyway arrangement (not shown) to prevent rotation with respect to each other when the coupling nut 32 is actuated. As well known in the art, by rotating the coupling nut 32 the interaction of the projections 42 with the grooves 44 causes the coupling nut and plug connector member 12 to be axially drawn toward the receptacle connector member 14. For further details of the structure of the connector 10, reference may be had to U.S. Pat. No. 3,393,927. It is to be understood that the structure of the connector disclosed herein is given by way of example only. The shielding member of the present invention may be utilized in most all forms of axially mated electrical connectors. While the socket contact 20 is shown mounted in the plug connector member 12, it will be understood that the socket contact could be mounted in the receptacle connector member 14 and the pin contact 26 mounted in the plug connector member 12. Furthermore, the connector 10 may employ a single pair of contacts or coaxial conductors rather than a plurality of mated contacts if desired.

The shielding member of the present invention, generally designated 50, is a helically coiled conductive spring formed as an annulus which is concentric with the central or longitudinal axis X--X of the connector 10. The spring is interposed between an annular shoulder 52 formed by the flange 34 on barrel 16 and the annular end surface 54 on the receptacle shell 18. As will be apparent, the spring 50 is positioned on the barrel 16 adjacent to the annular shoulder 52 prior to coupling of the plug and receptacle connector members.

As best seen in FIG. 3, the convolutions of the helically coiled conductive spring 50 are slanted at an oblique angle to the center axis X--X of the connector members, thereby providing what is generally known in the art as a "slant spring." Springs of this type are described in detail in U.S. Pat. Nos. 3,323,785 and 3,468,527. When an axial pressure is applied to the spring, an axial flattening of the spring occurs due to the folding of the convolutions upon each other and not due to distorting of the original diameter of the convolutions.

As illustrated in FIG. 1, the connector members 12 and 14 are partially mated so that no axial pressure is applied to the spring 50. However, when the connector members are fully mated so that the forward end 56 of the plug connector member 12 engages the facing seal 30, the axial distance between the facing surfaces 52 and 54 of the connector members is less than the normal outside helical diameter of the spring convolutions. Therefore, as seen in FIG. 4, the spring is axially flattened due to the convolutions folding over each other, to provide an almost continuous metal shield between the mating halves of the connector. The spring, therefore, provides excellent shielding against RFI and EMI. Also, because of the slant design of the spring convolutions, a wiping action occurs between the spring convolutions and the surfaces 52 and 54 when the connector members are mated together. This assures positive electrical continuity and thus effective grounding of the connector halves with respect to each other.

The grounding spring 50 is relatively rugged and inexpensive. It may be installed easily on any configuration of a connector member. For example, the spring may be mounted on rectangular connector bodies as well as cylindrical connector bodies. Also, no bonding or intermediate joining processes are required for holding the shielding member 50 of the present invention on the connector.

Claims

What is claimed is:

1. In an electrical connector comprising a first connector member having a first contact therein, a second connector member having a second contact for electrical connection with said first contact upon mating of said first and second connector members, said first and second connector members having a common central axis and being formed with parallel facing surfaces thereon surrounding said contacts, and a shielding member interposed between said facing surfaces for eliminating radio frequency and electromagnetic interference, the improvement which comprises:

said shielding member comprising a helically coiled conductive spring having convolutions each of which lies in a slanted plane that intersects said center axis of said connector members at an oblique angle;

coupling means other than said spring mounted on one of said connector members and engageable with the other connector member for coupling said connector members in mated engagement; and

the axial distance between said facing surfaces when said connector members are mated by said coupling means is less than the normal outside helical diameter of the convolutions of said spring, whereby said spring is axially flattened when said connector members are mated, thus providing RFI and EMI shielding.

2. An electrical connector as set forth in claim 1 wherein:

said connector members are coaxial cylindrical bodies, said first connector member having an outwardly extending annular shoulder thereon forming one of said facing surfaces and the second connector member having an annular end surface forming the other facing surface; and

said spring being formed as an annulus interposed between said annular shoulder and annular end surface.

3. An electrical connector as set forth in claim 1 wherein:

said coupling means surrounds said spring; and

one of said connector members is telescopically mounted within the other connector member.