GB1128939A - Printed circuit assemblies - Google Patents

Abstract

1,128,939. Printed circuit assemblies; cooling. INTERNATIONAL BUSINESS MACHINES CORP. 28 July, 1967, No. 34757/67. Heading H1R. To facilitate forced cooling of a circuit assembly, a plurality of printed circuit cards 12-15 (Fig. 1), each carrying a plurality of micro modules, are assembled on tubes 11, holes being provided in the tubes registering with spaces between cards, so that a stream of air from a fan (not shown) flows from an air distribution box 10 through the holes and between the cards to cool the micro-modules thereon. The spaces between adjacent modules on a card are blocked by spacers (Fig. 3, not shown), and spacers 37 (Fig. 7) between adjacent cards on the tube have baffles 53 to direct the stream of air close to projecting metal fins (24), Fig. 2 (not shown), on the modules, which fins create a turbulence and improve the heat exchange. Each air distribution tube 11 is of square cross-section and is constructed from four multi-layer printed circuit boards (Fig. 5, not shown) which provide the electrical interconnections between the cards 12, 13, 14, 15. Each card 12-17 and spacer 37 has a square central hole (Fig. 3, not shown) through which the tube 11 is passed on assembly. Printed circuit cards 16, 17 on each sub-assembly 6, 7, 8, 9, are interconnected by tapes 20 and conventional connectors 18, 19, and provide input/output connections to the circuit assembly Spring finger contacts 51, soldered on each card, engage printed circuit lands (33), Fig. 5 (not shown) on the tube 11, there being one pair of rows of lands to each card. Camming surfaces 54 on the spacers 36, 37 press the fingers 51 down on to the tube as axial pressure is applied to the stack of cards and spacers by a screw 43 on a tie-rod 40 acting against an end cap 41. Pins projecting from the micro-modules substrates are soldered into holes in the circuit cards, to provide electrical connections to the modules.