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Fulcrum Type, Dual Opposed, Triple Line Contact, EMC/EMI Shield for I/O Connectors

IP.com Disclosure Number: IPCOM000110621D
Original Publication Date: 1992-Dec-01
Included in the Prior Art Database: 2005-Mar-25
Document File: 4 page(s) / 126K

Publishing Venue

IBM

Related People

Cannon, LJ: AUTHOR [+2]

Abstract

This article describes a design solution for one-finger actuation of circuit-board mounted or electromechanical types of switches, where distance between switch and actuator must be variable and allowable, therefore requiring a long-stroke, self-restoring actuator.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Fulcrum Type, Dual Opposed, Triple Line Contact, EMC/EMI Shield for I/O Connectors

       This article describes a design solution for one-finger
actuation of circuit-board mounted or electromechanical types of
switches, where distance between switch and actuator must be variable
and allowable, therefore requiring a long-stroke, self-restoring
actuator.

      This article describes an improved new EMC/EMI shield design to
provide enhanced grounding of electronic I/O connectors and the
external signal cables which attach to them.

      See Figs. A, B and C.

      This new shield design uses opposite edges of the connector
flange as dual-opposed fulcrums to exert line-contact forces along
(1) inner perimeter of the shield where it contacts the mating
connector, (2) outer perimeter of the shield where it contacts the
chassis, and (3) the edges of the fixed connector on the motherboard
which act as fulcrums around which the shield is bowed to generate
the contact forces.

      A new shield design provides additional and heretofore
unavailable grounding between the male and female connector shells.
The application described here is for a SCSI-II I/O connector.  The
off the shelf SCSI I/O connector pair has multiple small contact
points which lack good independent spring action, and so some points
fail to make good electrical contact between the shells of some
connectors.  Historically, additional grounding of connector shells
had to be done by adding to the external connector a dedicated wire
braid with eye-terminal, and then screwing that eye-terminal to the
chassis.  This new shield design eliminates such extra braid and
screw hardware and also their related installation procedure.

      This new shield design creates essentially equal and opposite
vertical forces on the chassis which cancel each other out,
preventing unwanted forward-biased forces when trying to install
planar-mounting screws.  Typical shields mounted on planars push too
hard against the rear wall of the chassis making it difficult to line
up the planar-mounting holes to allow installation of planar-mounting
screws.

      The new shield design provides not just point-contact, but
lines of contact bet...