Heat sink fastener

A heat sink fastener includes an elongated clamping plate attached to a heat sink and having two clamping arms at two opposite ends respectively hooked in respective hook holes on a CPU module to secure the heat sink to the CPU module, and a holding down plate coupled to the clamping plate to hold down the clamping arms, the holding down plate having a longitudinal locating hole coupled to the clamping arms of the clamping plate to hold down the clamping arms in the respective hook hole on the CPU module, and a finger strip for pulling by hand to disengage the holding down plate from the clamping arms of the clamping plate.

BACKGROUND OF THE INVENTION 
The present invention relates to a heat sink fastener for securing a heat 
sink to a CPU module, and more particularly to such a heat sink fastener 
which can be quickly installed to secure a heat sink to a CPU module, and 
conveniently disconnected from the heat sink and the CPU module when 
desired. 
Various heat sink fastening devices have been disclosed for use to secure a 
heat sink to a CPU module. These heat sink fastening devices commonly use 
a locking lever for locking/unlocking control. However, the locking lever 
tends to be forced out of position when vibrated causing the heat sink 
fastening device to fall from the heat sink and the CPU module. 
SUMMARY OF THE INVENTION 
The present invention provides a heat sink fastener which eliminates the 
aforesaid problem. According to one aspect of the invention, the heat sink 
fastener comprises an elongated clamping plate attached to a heat sink and 
having two clamping arms at two opposite ends respectively hooked in 
respective hook holes on a CPU module to secure the heat sink to the CPU 
module, and a holding down plate coupled to the clamping plate to hold 
down the clamping arms, the holding down plate having a longitudinal 
locating hole coupled to the clamping arms of the clamping plate to hold 
down the clamping arms in the respective hook hole on the CPU module, and 
a finger strip for pulling by hand to disengage the holding down plate 
from the clamping arms of the clamping plate. According to another aspect 
of the present invention, clamping plate has reinforcing ribs raised from 
two opposite long sides of a flat middle base between the clamping arms to 
reinforce the structural strength against deformation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIGS. 1 and 2, a heat sink fastener in accordance with the 
present invention is generally comprised of a clamping plate 1, and a 
holding down plate 2. 
The clamping plate 1 comprises an elongated flat base 11, a first clamping 
arm 12 and a second clamping arm 13 respectively extended from two 
opposite ends of the flat base 11, a horizontal slot 122 at the first 
clamping arm 12, a springy projecting hook 132 integral with the second 
clamping arm 13, a first hooked portion 121 at one end of the first 
clamping arm 12 remote from the flat base 11, and a second hooked portion 
131 at one end of the second clamping arm 13 remote from the flat base 11. 
The holding down plate 2 comprises a longitudinal locating hole 21, and a 
finger strip 211 at one end. Further, reinforcing ribs 111;112 are raised 
from the flat base 11 of the clamping plate 1 along two opposite long 
sides thereof. The reinforcing ribs 11;112 reinforce the structural 
strength of the flat base 11 against deformation. 
Referring to FIG. 3, when the curved middle portions of the clamping arms 
12;13 of the clamping plate 1 are inserted into the longitudinal locating 
hole 21 on the holding down plate 2, the horizontal slot 122 of the first 
clamping arm 12 of the clamping plate 1 is forced into engagement with an 
end edge of the longitudinal locating hole 21 of the holding down plate 2, 
and then the finger strip 211 is pulled downwards with the hand, enabling 
the other end edge of the longitudinal locating hole 21 of the holding 
down plate 2 to be moved over the springy projecting hook 132 and forced 
into engagement with the bottom edge of the springy projecting hook 132. 
Referring to FIGS. 4 and 5, when a heat sink 3 is attached to a CPU module 
4, the flat base 11 of the clamping plate 1 is attached to the heat sink 
3, and the hooked portions 121;131 of the clamping arms 12;13 of the 
clamping plate 1 are hooked in respective hook holes 42 on the CPU module 
4, and then the holding down plate 2 is coupled to the clamping plate 1 to 
secure the clamping plate 1 in place. When the two opposite end edges of 
the longitudinal locating hole 21 of the holding down plate 2 are 
respectively forced into engagement with the horizontal slot 122 on the 
first clamping arm 12 and the springy projecting hook 132 at the second 
clamping arm 13, the clamping arms 12;13 are forced inwards toward each 
other, and therefore the hooked portions 121;131 are firmly retained in 
engagement with the respective hook holes 42 on the CPU module 4. 
While only one embodiment of the present invention has been shown and 
described, it will be understood that various modifications and changes 
could be made thereunto without departing from the spirit and scope of the 
invention disclosed.