Electrical connectors – With vitreous-type envelope – Having bayonet-coupling contact
Reexamination Certificate
2000-10-05
2002-03-12
Paumen, Gary (Department: 2833)
Electrical connectors
With vitreous-type envelope
Having bayonet-coupling contact
Reexamination Certificate
active
06354879
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to electrical connectors and specifically to electrical connectors for terminating to conductors of a shielded cable.
BACKGROUND OF THE INVENTION
In many applications, particularly in military and aerospace applications, shielded cable, such as cable in accordance with the M27500 cable specification, is used. Typically, the shielded cable includes not one but a plurality of conductive shields surrounding one or more conductors in the cable. Typically, a single shield surrounds at least one and no more than ten conductors. In some cases, an outer conductive shield will surround the plurality of conductive shields and shielded conductors. The shields protect the signals transmitted along the conductors from electromagnetic interference (EMI) due to electromagnetic radiation in the ambient atmosphere. The shields must be grounded to protect the conductors from EMI. Typically, the connector includes a conductive backshell that grounds the shields when the connector is plugged into a receptacle.
The ground to the backshell can be effectuated by a number of approaches. In one approach, one or more shields are soldered to a conductor which is connected to the backshell. The shields can be daisy chained together by soldering to utilize the same ground conductor. The daisy-chained shields and conductor are typically located inside of the backshell to protect them from EMI. As will be appreciated, exposing the daisy chained shields to electromagnetic radiation in the external environment can seriously compromise or degrade the EMI resistance of the shields. The EMI resistance is further weakened by the build up of electrical resistance from shield to shield along the daisy chain. The use of soldering and daisy chaining is not only labor intensive but also produces “brown crud” contamination from the solder flux. The “brown crud” is solder flux that wicks up underneath the jacket along the shield braid. Brown crud contamination is a type of corrosion that is unacceptable in many applications.
In other approaches, the shields are engaged with a clamping ring or coil spring and the ring or spring compressed between a metal seat and a tightened metal nut. Although the grounded portion of the conductive shields are well protected by the outer wall of the seat and the nut from exposure to electromagnetic interference, the nut often requires the shield to be cut to the proper length and properly positioned to permit the nut to be engaged properly with threads located on the outer wall of the seat. Otherwise, the shields could engage the threads and interfere with nut tightening and/or generate loose pieces or fragments of the conductive shield(s). In many applications, the shield must be temporarily clamped or otherwise held in position before the nut is tightened to effectuate the ground. Even when the shields are cut to the proper length, rotation of the ring or spring in the seat during rotation of the nut can cause the grounded shields to rub or abraid or otherwise frictionally contact against the seat, which can cause small fragments of the shield to be broken off. Such small fragments can later be dislodged, such as during the launch of a space vehicle, causing electrical shorts and vehicle malfunctions. The ability to remove such debris is hindered by the inaccessibility of the grounded shields after the nut is tightened. The grounded shields are generally not visible after nut tightening, complicating inspection of the integrity of the ground connection. The ground structure in such connectors is radiused, which provides a high profile for the connector, thereby creating problems where space is at a premium.
SUMMARY OF THE INVENTION
These and other needs are addressed by one or more embodiments of the present invention. Generally, the present invention provides a connector that utilizes a ground structure located inside of the backshell to provide ease of shield grounding.
In one embodiment, a connector for terminating a plurality of shielded conductors is provided that includes:
(a) a conductive backshell housing including a passage for receiving a plurality of conductors, the passage being disposed at a distal end of the conductive backshell housing;
(b) a connecting structure including a plurality of connecting elements for connecting to the corresponding plurality of conductors wherein each of a plurality of conductive shields surrounds one or more of the plurality of conductors, the plurality of connecting elements being disposed at a proximal end of the conductive backshell housing;
(c) one or more ground structures for grounding each of the plurality of conductive shields, each of the one or more ground structures being located inside the conductive backshell housing between the plurality of connecting elements and the passage; and
(d) a strain relief structure for restraining movement of the plurality of shielded conductors relative to the backshell housing.
The backshell housing can be composed of any conductive material and/or superconducting material and/or a composite of a conductive material and/or a superconducting material with a nonconducting material and/or a nonsuperconducting material. By way of example, the backshell housing can be composed of a plastic substrate with a metal coating. The backshell housing can be rectangular, circular, eliptical, or any other suitable cross-sectional shape and can be an integral or nonintegral (e.g., multipiece) assembly unit.
The connecting structure and connecting elements can be of any suitable configuration. Typically, the connecting structure has stacked rows of pin-type contacts.
The ground and strain relief structures can also be of any suitable configuration. For example, the structures can each include one or more movable clamping bars, jaws, or openings having smooth, serrated, ribbed, knurled, etc., configurations or edges that may be a part of or mounted on one or more parts of the backshell. In one configuration, the strain relief structure clamps the plurality of shielded conductors between a stationary bar (or a portion of the backshell) and a moveable bar and is located inside the backshell housing and near an opening of the passage. In one configuration, the ground structure clamps the conductive shield between a stationary bar (which is typically attached in some fashion to the backshell housing) and a surface of the conductive backshell housing (or another stationary bar).
In one configuration, the strain relief structure contacts an insulative cover enclosing the conductive shield and the plurality of shielded conductors. As will be appreciated, most shielded cables will have an insulated or dielectric (e.g., thermoplastic) cover. The cover is typically removed only as necessary to access the shields and the individual conductors, with the cover commonly being left in place where the cable contacts the strain relief structure.
The strain relief structure and ground structure can be located at any suitable location in the backshell. In one configuration, the strain relief structure is located between the ground structure and the distal end of the backshell housing. In another configuration, the ground structure is located between the ground structure and the distal end of the backshell housing.
The ground and strain relief structures can be formed by one or more integral or nonintegral components. In one configuration, the ground and/or strain relief structure includes a single unitary (or integral) bar for clamping or compressing a plurality of conductive shields or the cable, respectively. The bar (for either the ground and/or strain relief structure) may be moved or displaced by any suitable connector or connecting means such as one or more screws, a cam, a lever, a rivet, and a ratchet and locked or held in place by any suitable means such as one or more of a hook, a latch, a screw, a solder, a weld (e.g., a spot weld, an ultrasonic weld, etc.), a magnet, a rivet, an adhesive, and a lock washer. In another configuration, a plurality of ground stru
Ball Aerospace & Technologies Corp.
Nguyen Phuong
Paumen Gary
Ross P.C. Sheridan
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