Socket apparatus for removably mounting electronic packages with improved contacting system

A socket for removably receiving an electronic package having a plurality of terminals arranged according to a selected pattern, for connecting said electronic package to circuit paths on an external substrate comprising:

• a base formed of electrically insulative material, the base having a bottom and an upstanding sidewall thereabout forming a centrally disposed recess,
• a support member received in the recess of the base, the support member formed of electrically insulative material and having a top surface formed with a recessed contact film receiving surface,
• a sheet of electrically insulative, flexible contact film having a plurality of spaced apart, electrically conductive contact members thereon arranged according to the selected pattern, the sheet received on the contact film receiving surface,
• a plurality of bores formed through the support member in the selective pattern,
• a terminal pitch expansion substrate mounted on the base between the base and the support member, the terminal pitch expansion substrate having a top surface formed with a plurality of contact pads thereon arranged according to the selected pattern and aligned with the bores in the support member, the expansion substrate having a plurality of circuit paths with each contact pad electrically connected to a respective circuit path,
• an electrically conductive spring contact element received in each bore in the support member, the spring contact elements having an upper end in engagement with a respective contact member and a lower end in engagement with a respective contact pad on said terminal pitch expansion substrate,
• an adapter received in the recess of the base above the support member, the adapter having a terminal receiving opening formed therethrough and having an electronic package seat circumscribing the opening, the electronic package seat being located so that the terminals of an electronic package received on the electronic package seat engage respective contact members,
• a plurality of socket terminals extending through the bottom of the base, a respective socket terminal being electrically connected to a respective circuit path on said terminal pitch expansion substrate path,
• and a compression member mounted on the base and movable toward and away from the electronic package seat for applying a force to an electronic package received on the seat with the force in turn being transferred through the contact members to the spring contact elements.