GB1128940A - Printed circuit assembly - Google Patents

Abstract

1,128,940. Printed circuit assemblies. INTERNATIONAL BUSINESS MACHINES CORP. 28 July, 1967, No. 34758/67. Heading H1R. [Also in Division H2] A circuit assembly comprises a plurality of sub-assemblies 6, 7, 8, 9 (Fig. 1, not shown) each including a plurality of printed circuit cards 12 to 15 which support and provide interconnections between a plurality of integrated circuit modules 22 (Fig. 3) and Fig. 2 (not shown), arranged around an aperture 26 in each card, through which aperture extends an air distribution tube 11 formed by four multi-layer printed circuit cards 32 (Fig. 5) carrying printed wiring interconnecting the printed circuit cards 12 to 15. As shown Fig. 7, between each pair of adjacent cards is a spacer 36, 37. Spring fingers 51 are soldered to printed lands at the edges of the apertures 26 of the cards 12 to 17. When assembling the cards and spacers axially on to the tube 11, the fingers do not exert much pressure thereon. Camming surfaces 54 on the spacers 36, 37 however, press the fingers 51 against the tube lands 33 (Fig. 5), as axial force is applied to the stack of cards and spacers by a screw 43 on a tie-bar 40 acting on an end cap 41. Printed circuit interconnection cards 16, 17 which may or may not carry modules provide input/output connections to the circuit assembly. Printed lands around the central aperture S of 16, 17 are connected by the spring fingers to the printed circuit tube, and are connected to lands around their outer edges. The outer edge lands of cards 16, 17 are connected by conventional connectors and tape cables to the interconnection cards of the other sub-assemblies (Fig. 1, not shown). The micro-modules 22 (Fig. 2, not shown) each comprise integrated circuits on a substrate and encapsulated in a metal can. Electrical connection pins, projecting from the substrate, are soldered into holes in the printed circuit cards. Cooling air from a fan passes through the tubes 11, out through apertures therein, which register with the spaces between the cards, and across the micro-modules. Plated holes and strips are provided at the outer edges of each card and are connected to the circuitry for testing purposes.