Browse Prior Art Database

Radio Frequency Interference-Sealed Chassis

IP.com Disclosure Number: IPCOM000102105D
Original Publication Date: 1990-Oct-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 2 page(s) / 56K

Publishing Venue

IBM

Related People

Coles, RJ: AUTHOR [+3]

Abstract

Disclosed is the use of part of a power supply case as a radio frequency interference (RFI) screen at the back of an electronic equipment chassis. A rear cover plate is screwed to a picture frame bulkhead which is welded to the chassis by a tag and slot system. The pitch of the tags is chosen to suit the RFI frequency. A simple RFI gasket may be interposed between plate and frame to ensure good contact.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 74% of the total text.

Radio Frequency Interference-Sealed Chassis

       Disclosed is the use of part of a power supply case as
a radio frequency interference (RFI) screen at the back of an
electronic equipment chassis.  A rear cover plate is screwed to a
picture frame bulkhead which is welded to the chassis by a tag and
slot system.  The pitch of the tags is chosen to suit the RFI
frequency.  A simple RFI gasket may be interposed between plate and
frame to ensure good contact.

      At the rear of a steel chassis containing an RFI source, such
as a power supply, there are potential leakage points for RFI to
escape through, e.g., joints between side panels and rear cover.  The
chassis construction described minimizes the problem and allows for
the addition of complete sealing if needed.

      Referring to Fig. 1, the rear of a chassis is shown without a
cover plate 1 fitted.  Top 3, bottom 4 and sides form a trunk and are
secured to a picture frame bulkhead 2. A cover plate 1 shown in Fig.
2 is used to close the rear part of the power supply.  Cover plate 1
seats on and is screwed to a picture frame bulkhead 2 which is
recessed inside the trunk formed by top 3, bottom 4 and sides of the
chassis.  When assembled in position the shape of the plate 1 fitting
into the recessed bulkhead 2 provides a low leakage labyrinth as well
as close electrical contact.  If the requirement is for stricter RFI
containment, then a simple RFI gasket may be trapped between the
cover plate 1 and...