Locking apparatus and loadboard assembly

A system for testing a semiconductor device by establishing electrical contact between said device and a plurality of pins on a test head, said system comprising:

• a circuit board for mounting said device thereon;
• a mounting plate connected to said circuit board, said mounting plate comprising an outer member having a plurality of cam followers, an inner member and a plurality of radial members, the outer member surrounding the inner member, said radial members extending inwardly from said outer member to retain the inner member in a centered position relative to said outer member wherein the outer member, the inner member and the radial members define a plurality of apertures, said plurality of pins extending through the plurality of apertures;
• a cam member adapted to be secured to said test head, said cam member having a plurality of inclined cam slots, each cam slot having a top opening opposite the test head to receive a cam follower of said mounting plate and extending downward from the top opening toward the test head along an inner peripheral surface and terminating at a lower closed end, said cam member further having a plurality of rollers for movably supporting said cam member on the test head;
• and
• a plurality of rails adapted to be mounted on the test head and engaged with the rollers, each rail adapted to secure and guide a roller,
• wherein movement of said cam member in a horizontal plane relative to the test head engages the cam followers of the mounting plate to follow the cam slots such that said mounting plate and said circuit board move in a vertical direction relative to said test head such that said pins extending through said plurality of apertures contact said circuit board to establish said electrical contact.