US005995368A [ii] Patent Number: 5,995,368  Date of Patent: Nov. 30,1999
 AIR FLOW DISTRIBUTION DEVICE FOR SHELF-BASED CIRCUIT CARDS
 Inventors: Chi Keung Lee, Gloucester; William David Jeakins, Kanata, both of Canada
 Assignee: Nortel Networks Corporation,
 Appl. No.: 09/175,620  Filed: Oct. 20, 1998
 Int. CI.6 H05H 7/20
 U.S. CI 361/695
 Field of Search 62/259.2; 454/184;
361/688, 690, 694-697, 724, 736, 752,
 References Cited
U.S. PATENT DOCUMENTS
4,750,088 6/1988 Frict 361/694
4,860,163 8/1989 Sarath .
5,027,254 6/1991 Corfits et al 361/694
5,506,751 4/1996 Chatel 361/690
FOREIGN PATENT DOCUMENTS
2197536 5/1988 United Kingdom .
Primary Examiner—Gregory Thompson  ABSTRACT
A device for improving air flow around shelf-based circuit cards housed within a card cage is disclosed where at least one fan is located above a rear portion of the card cage to draw air from beneath a forward portion of the card cage. The device is generally rectangular, having a forward portion, a rear portion and two side portions. A plurality of spaced parallel flanges extend from one side portion to the other side portion. Each flange, in cross-section, has an inverted L-shape, with a vertical section and a horizontal section, the horizontal section extending from the vertical section towards the forward portion of the device. Preferably, the height of the vertical section is a least 1.2 times the width of the horizontal section and the distance between adjacent flanges is at least the height of the vertical section. Also, preferably, the device is shaped from a single piece of sheet metal. The device is connected beneath the card cage with the forward portion of the device connected to the front cross member of the card cage and the rear portion connected to the rear cross member of the card cage.
8 Claims, 5 Drawing Sheets