Patent ID: 7885072

Claim:
A fixing device fastening a heat sink having a base which defines a plurality of assembling holes at two opposite sides of a bottom portion of the base to one of motherboards with different specifications each of which defines a plurality of extending holes therethrough, the fixing device comprising: a plurality of slats each having an end thereof pivotally connecting to the base of the heat sink, another end of each slat defining an elongated slot corresponding to one of the extending holes of the one of the motherboards; a back plate defining a plurality of mounting holes corresponding to the extending holes of the one of the motherboards, in which at least some of the mounting holes of the back plate align with the extending holes of the one of the motherboards, each mounting hole of the back plate being a counterbore and comprising a first receiving hole and a second receiving hole located under and in communication with a lower portion of the first receiving hole, a diameter of the first receiving hole of the mounting hole of the back plate being larger than that of the second receiving hole to form a baffling portion between the first receiving hole and the second receiving hole, the first receiving hole being hexagonal; and a plurality of fixing units secured on the one of the motherboards; wherein the fixing units each extend through the elongated slot of a corresponding slat, a corresponding extending hole of the one of the motherboards and a corresponding mounting hole of the back plate to secure the heat sink, the slats, the one of the motherboards and the back plate together; and wherein each of the fixing units comprises a bushing, a screw engaging with a bottom of the bushing and a fastener engaging with a top of the bushing, the bushing defining a threaded hole in a center thereof and comprising a grasping portion and an inserting portion extending downwardly from the grasping portion, the inserting portion extending downwards through a corresponding extending hole of the one of the motherboards and engaging with the screw.