US Patent 7405939 Fastening device and heat sink assembly using the same

A heat sink assembly (100) includes a fastening device (20) and a heat sink (10). The fastening device includes a sleeve (24), a pin (22) received in the sleeve and a biasing means (26) disposed around the sleeve. The sleeve includes a locking portion (246) formed at a bottom end thereof. The pin includes an engaging portion (226) formed at a bottom end thereof. At least a slot (248) is defined through the locking portion of the sleeve (24). The engaging portion extends outwardly through the slot and resiliently abuts against a bottom surface of the heat sink. The biasing means is slightly deformed between a top end of the fastening device and a top surface of the heat sink, thereby keeping the fastening device in a vertical position with respect to the heat sink.