Pluggable electronic circuit package assembly with snap together heat sink housing

Heat sink apparatus for an electronic circuit package assembly, said package assembly including a planar printed circuit substrate having a rectangular configuration and first and second parallel major outer surfaces with first and second predetermined circuit patterns, respectively, thereon, and conductive means in said substrate for interconnecting said first and second patterns, said substrate having a predetermined first region including therein a portion of at least said first circuit pattern, said portion having at least one row of input/output printed circuit terminals, said row of input/output printed circuit terminals being in substantial parallel alignemtn with and located in substantial proximity to a predetermined edge of said substrate, said predetermined edge and said input/output printed circuit terminals being pluggable into a compatible edge type connector for connection thereto,

• and said assembly further having at least one first row of first integrated circuit chip means mounted on said first major surface and connected to said first circuit pattern, at least one second row of second integrated circuit chip means mounted on said second major surface and connected to said second circuit pattern, said mounted first and second chip means having a predetermined first height profile, said first and second rows of mounted chip means being in substantial parallel alignment with said predetermined edge, said mounted first and second chip means further being located in a second region of said substrate, at least one row of circuit components mounted on at least a predetermined one of said major surfaces and connected to said circuit pattern on said major surface on which said circuit components are mounted, said mounted circuit components having a predetermined second height profile larger than said first height profile, said row of said circuit components being in substantial parallel alignment with said predetermined edge, said circuit components further being located in a third region of said substrate, said heat sink apparatus comprising:
• heat sink housing means having first and second heat sink housing members in an abutting facing relationship defining an enclosure for enclosing therein said second and third regions of said substrate and said mounted chip means and said circuit components located respectively therein, and said first region and said predetermined edge being extended outwardly from said enclosure;
• and
• retention means for retaining said first and second heat sink housing members together and said substrate in registration with said enclosure defined thereby, said retention means further comprising a first retention post extending from one of said first and second heat sink housing members and a first recess in the other of said first and second heat sink housing members for receiving therein said first post with a predetermined tolerance fit to retain said first and second heat sink housing members together, said substrate further having a first opening extending there through, said first post passing through said first opening to maintain said substrate in said registration with said enclosure.