Electrical connectors – With circuit conductors and safety grounding provision
Reexamination Certificate
1999-06-16
2001-07-24
Abrams, Neil (Department: 2839)
Electrical connectors
With circuit conductors and safety grounding provision
C439S939000, C439S927000
Reexamination Certificate
active
06264480
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to electrical connectors, and, more particularly, to devices and methods for shielding and grounding.
BACKGROUND OF THE INVENTION
Radio frequency (RF) components, assembled boards and modules radiate both desirable and undesirable emissions. The desirable emissions are those that the components, assembled boards and modules are designed to emit. The undesirable emissions should be suppressed to avoid interference with other equipment. In cellular base station equipment, this is especially true because of the close proximity of other components, assembled boards and modules in the base station. Such components may also be subjected to undesirable RF emissions from external sources.
Attempts have been made to provide shielding and grounding to suppress unwanted emissions between RF modules that are mounted closely together and plugged into a common backplane. One attempt to solve this problem utilizes a conductive adhesive gasket and a conductive adhesive tape. The conductive adhesive gasket is applied to the RF module chassis and the conductive adhesive tape is applied to the backplane. When the RF module is mounted, the gasket on the RF module chassis touches the tape on the backplane.
Unfortunately, the adhesive backed gasket is fragile and tends to become damaged with repeated removal and handling of the RF module. The adhesive backed gasket may also peel off rather easily if the backplane surface has not been cleaned and prepared properly prior to application of the gasket. The damaged gasket may fail to seal properly, or worse, may physically interfere with the mounting of the module. Another shortcoming of this technique is that the gasket and the tape are typically aligned and applied by hand. The conductive tape should be properly located to allow proper electrical contact with other portions of the backplane and the mounting frame to which it is fastened. The mounting surfaces should be prepared properly by cleaning, which is also typically a hand operation. The results are often inconsistent, leading to poor quality and poor shield performance.
SUMMARY OF THE INVENTION
The present invention is directed to a shield and grounding method for reducing unwanted emissions between modules that are mounted closely together and plugged into a common backplane. According to one aspect of the present invention, an RF emissions shield for grounding a chassis to an associated connector mounted on a backplane includes a shield body, mounting means for securing the shield body to the backplane, and grounding means for electrically connecting the shield body to the connector. At least one spring member is integral with the shield body and is adapted to engage the chassis such that the spring member is biased against the chassis. Preferably, the at least one spring member includes a plurality of curved, resilient fingers extending from an edge of the shield body.
According to another aspect of the present invention, an RF emissions shield for grounding a chassis to an associated connector mounted on a backplane includes a shield body having an edge. An aperture is defined in the shield body. The aperture is sized and configured to receive the connector such that at least an engagement portion of the shield body along the aperture engages the connector to secure the shield body to the backplane and to electrically connect the shield body to the connector. A plurality of curved, resilient spring fingers extend from the edge. Preferably, the shield body is substantially planar. More preferably, the spring fingers extend above the plane of the shield body. The shield may include a tab integral with the shield body and extending into the aperture, the tab adapted to be deflected by and engage the connector when the connector is inserted into the aperture.
According to a further aspect of the present invention, an RF emissions shielded connector assembly for use with a chassis includes a backplane assembly and a shield for grounding the chassis. The backplane assembly includes a backplane, and a connector extending from the backplane. The shield is secured to the backplane assembly and includes an electrically grounded shield body and at least one spring member integral with the shield body. The at least one spring member is adapted to engage the chassis such that the spring member is biased against the chassis. Preferably, the at least one spring member includes a plurality of curved, resilient fingers extending from an edge of the shield body. Preferably, the connector is electrically grounded, the shield includes an aperture defined in the shield body, and the connector extends through the aperture and engages at least an engagement portion of the shield disposed along the aperture.
According to a further aspect of the present invention, an RF emissions shielded connector system includes a connector module and a connector assembly. The connector module includes an electrically conductive chassis and a first connector mounted on the chassis. The connector assembly includes a backplane assembly and a shield for grounding the chassis. The backplane assembly includes a backplane and a second connector extending from the backplane and adapted to engage the first connector. The shield is secured to the backplane assembly and includes an electrically grounded shield body and at least one spring member integral with the shield body. The at least one spring member is adapted to engage the chassis when the first and second connectors are engaged such that the spring member is biased against the chassis. Preferably, the at least one spring member includes a plurality of curved, resilient fingers extending from an edge of the shield body. Preferably, the second connector is electrically grounded, the shield includes an aperture defined in the shield body, and the second connector extends through the aperture and engages at least an engagement portion of the shield disposed along the aperture.
According to another aspect of the present invention, a method for connecting a connector module having a chassis to a backplane assembly including a backplane and a connector extending from the backplane includes mounting a grounding shield on the backplane assembly such that the shield is electrically grounded to the backplane assembly. The shield includes a shield body and at least one spring member integral with the shield body. Thereafter, the connector module is connected to the backplane assembly such that the at least one spring member engages and is biased against the chassis.
Objects of the present invention will be appreciated by those of ordinary skill in the art from a reading of the Figures and the detailed description of the preferred embodiments which follow, such description being merely illustrative of the present invention.
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“Strip Metal Gaskets and Grounding Products”; Instrument Specialties Internet Website (www.instr.com/ps/ps13stripmetgas.html); Mar. 19, 1999.
“Material Characteristics Chart—Fingerstock”; Instrument Specialties Internet Website (www.instr.com/mc/mc13fingerstock.html); Mar. 19, 1999.
International Search Report, Sep. 6, 2000, for Application No. PCT/US00/14260.
Denzene Quentin Scott
Nealis Edwin John
Abrams Neil
Duverne J. F.
Ericsson Inc.
Myers Bigel & Sibley & Sajovec
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