Patent ID: 7808791

Claim:
A fastener adapted for assembling a heat sink and a printed circuit board together comprising: a connecting pole comprising a shaft, a head and a thread portion, the head and the thread portion being at opposite ends of the shaft, respectively; a sleeve receiving the connecting pole therein, the sleeve comprising an engaging portion and a receiving portion extending from an end of the engaging portion, the engaging portion enclosing a top end of the shaft of the connecting pole therein and abutting against the head of the connecting pole, the receiving portion enclosing a bottom end of the shaft and a top end of the thread portion of the connecting pole therein, the receiving portion comprising a plurality of spaced resilient pieces; an elastic element enclosing a periphery of the engaging portion of the sleeve; and a baffling portion screwing onto the thread portion of the connecting pole; wherein when the connecting pole rotates relative to the sleeve, the baffling portion moves upwardly along a longitudinal direction of the thread portion of the connecting pole to enter the receiving portion of the sleeve and push the pieces of the receiving portion to make the pieces move outwards.