U.S. patent application number 09/736987 was filed with the patent office on 2001-05-31 for clamping heat sinks to circuit boards over processors.
Invention is credited to Bookhardt, Gary L., McEuen, Shawn S..
Application Number | 20010002160 09/736987 |
Document ID | / |
Family ID | 23786690 |
Filed Date | 2001-05-31 |
United States Patent
Application |
20010002160 |
Kind Code |
A1 |
Bookhardt, Gary L. ; et
al. |
May 31, 2001 |
Clamping heat sinks to circuit boards over processors
Abstract
A heat sink may be spring strapped onto a socketed processor
using clips that engage the spring strap and that are
pre-positioned on the circuit board. The clips may be C-shaped and
may include an upper spring arm portion, a vertical portion, and a
base which may be surface mounted to the circuit board. The upper
spring arm of the C-shaped clip then releasably engages the spring
strap to clamp the heat sink firmly onto the socketed
processor.
Inventors: |
Bookhardt, Gary L.; (Aloha,
OR) ; McEuen, Shawn S.; (Hillsboro, OR) |
Correspondence
Address: |
TROP PRUNER & HU, PC
8554 KATY FREEWAY
SUITE 100
HOUSTON
TX
77024
US
|
Family ID: |
23786690 |
Appl. No.: |
09/736987 |
Filed: |
December 14, 2000 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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09736987 |
Dec 14, 2000 |
|
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|
09450080 |
Nov 29, 1999 |
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Current U.S.
Class: |
361/704 ;
257/E23.086 |
Current CPC
Class: |
H01L 2924/00 20130101;
H05K 3/305 20130101; H01L 2924/0002 20130101; H05K 3/301 20130101;
Y10T 24/44026 20150115; H01L 23/4093 20130101; H01L 2924/0002
20130101; Y10T 29/4913 20150115 |
Class at
Publication: |
361/704 |
International
Class: |
H05K 007/20 |
Claims
What is claimed is:
1. A method comprising: securing at least two clips to a circuit
board; and clamping a heat sink over a processor on said circuit
board using said clips.
2. The method of claim 1 wherein securing at least two clips to a
circuit board includes securing said clips to said circuit board
using surface mount techniques.
3. The method of claim 2 wherein securing at least two clips to a
circuit board includes using a pick and place machine to position
said clips on said circuit board.
4. The method of claim 3 wherein securing at least two clips to a
circuit board includes securing a plurality of clips to a tape.
5. The method of claim 4 wherein securing at least two clips to a
circuit board includes removing said clips from said tape and
positioning said clips on said circuit board using a pick and place
machine.
6. An electronic device comprising: a circuit board; a processor
socket secured to said circuit board; a processor mounted in said
socket; a heat sink positioned over said socket and said processor;
at least two clips mounted on said circuit board on two opposed
sides of said heat sink; and a spring clamp extending from a clip
on one side of said heat sink to a clip on the other side of said
heat sink so as to resiliently clamp said heat sink onto said
processor.
7. The device of claim 6 wherein said clips are C-shaped.
8. The device of claim 6 wherein said clips are secured to said
circuit board using surface mount techniques.
9. The device of claim 8 wherein each clip is C-shaped including a
base which is secured to said circuit board by surface mount
techniques and a cantilevered leaf spring arm, which engages said
spring clamp, said arm coupled to said base.
10. The device of claim 9 wherein said spring clamp includes an
opening and said cantilevered leaf spring arm including a
downwardly directed catch, said catch releasably engagable by said
opening.
11. A system for clamping a heat sink over a socketed processor on
a circuit board comprising: a spring clamp having at least two
opposed spring arms, each spring arm including an opening; and a
pair of C-shaped clips, each clip including a cantilevered spring
arm, said spring arm including a catch, said catch releasably
engagable in said opening, said clips including a base that may be
secured to a circuit board.
12. The system of claim 11 wherein each clip includes a vertical
portion coupling said base and said cantilevered spring arm.
13. The system of claim 12 wherein said catch is a downwardly
turned portion of the end of said cantilevered spring arm.
14. The system of claim 13 wherein said base and said cantilevered
spring arm are substantially planar and are substantially parallel
to one another.
15. A clip for strapping heat sinks onto processors on circuit
boards comprising: a substantially planar base; an upstanding
portion coupled to said base; a cantilevered leaf spring coupled to
said upstanding portion; and a catch on said spring to releasably
engage a heat sink clamp.
16. The clip of claim 15 wherein said catch is a downwardly turned
end portion of said cantilevered leaf spring.
17. The clip of claim 16 wherein said spring and said base are both
substantially planar and are substantially parallel to one
another.
18. The clip of claim 16 wherein said spring has a pair of opposed
edges, one edge coupled to said portion and the other edge forming
said catch.
19. The clip of claim 18 wherein said base has a pair of opposed
edges, one of said edges coupled to said spring.
20. The clip of claim 15 being generally C-shaped.
Description
BACKGROUND
[0001] This invention relates generally to techniques for securing
heat sinks to processors.
[0002] Conventionally, a processor is mounted in a socket on a
motherboard such as a printed circuit board including a plurality
of integrated circuits secured thereto. The integrated circuits may
be electrically coupled by conductive lines printed on the circuit
board. Heat dissipation affects the operation of the processor and
thus it is desirable to have a highly effective and relatively
compact heat sink for the processor.
[0003] Commonly clips are provided on the socket for the processor.
Straps that connect to those clips are used to clamp a heat sink
over the processor contained in the socket. This technique provides
a firm spring attachment between the heat sink and the processor
and is effective in dissipating heat from the processor.
[0004] However many available sockets do not include the clips for
spring strapping the heat sink onto the socket. While it would be
desired to use a spring clip strapping technique, there is no way
to attach the strap so as to secure the heat sink over the
processor.
[0005] Thus there is a need for a way to spring strap heat sinks
onto processors secured in sockets without strap attaching
clips.
SUMMARY
[0006] In accordance with one aspect, a method includes securing at
least two clips to a circuit board. A heat sink is clamped over a
processor on the circuit board using the clips.
[0007] Other aspects are set forth in the accompanying detailed
description and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 a perspective view of a socketed processor secured to
a circuit board, in accordance with one embodiment of the present
invention;
[0009] FIG. 2 is a perspective view of a heat sink positioned atop
the socketed processor shown in FIG. 1, in accordance with one
embodiment of the present invention;
[0010] FIG. 3 is a perspective view of a heat sink clamped over a
socketed processor, in accordance with one embodiment of the
present invention;
[0011] FIG. 4 is a partial, enlarged cross-sectional view taken
generally along the line 4-4 in FIG. 3;
[0012] FIGS. 4a, 4b are partial, enlarged cross-sectional view
showing the sequence of attaching a spring loaded strap to a clip
in accordance with one embodiment of the present invention;
[0013] FIG. 5 is a top plan view of a tape containing a plurality
of clips in accordance with one embodiment of the present
invention;
[0014] FIG. 6 is a cross-sectional view taken generally along the
line 6-6 in FIG. 5 as the clip is being picked up by a pick and
place machine; and
[0015] FIG. 7 is a cross-sectional view of one embodiment of the
present invention showing the placement of a clip on a circuit
board.
DETAILED DESCRIPTION
[0016] Referring to FIG. 1, a processor 11 is mounted in a socket
12 which is secured to a circuit board 14 such as a printed circuit
board. The socket 12 may provide electrical connections between the
processor 11 and the circuit board 14. A plurality of C-shaped
clips 10 are secured to the circuit board 14 in an opposed
relationship adjacent the socket 12. A screw attachment 16 may be
utilized to fix the socket 12 on the circuit board 14. In one
embodiment of the present invention, the circuit board 14 is a
motherboard.
[0017] As shown in FIG. 2, a heat sink 18 may be positioned atop
the socket 12 over the socketed processor 11. Any of variety of
heat sinks may be utilized. The heat sink shown in FIG. 2 is a
so-called low profile heat sink. However other heat sinks may be
utilized including those which include upstanding heat dissipating
fins.
[0018] The heat sink 18 may be clamped over the socketed processor
11 using a spring loaded clamp 20, as shown in FIG. 3. The clamp 20
may include a bowed, central leaf spring portion 28 and a pair of
spring arms 24 and 26 which are opposed to a spring arm 22. The
spring arm 22 engages the clip 10c, the spring arm 26 engages the
clip 10b, and the spring arm 24 engages the clip 10a. While an
embodiment using three spring arms 22, 24, and 26 is illustrated,
more or fewer spring arms may be utilized in various
embodiments.
[0019] The spring loaded strap 20 provides a spring force which
securely presses the heat sink 18 into physical contact with the
socketed processor 11. In this regard, the strap 20 is
advantageously made of a highly resilient material such as spring
steel. Likewise, the C-shaped clips 10 may provide a spring action
between the point of securement of the clips to the circuit board
14 and the rest of the strap 20. That is, the clips 10 may act as
leaf springs which act in concert with the spring action arising
from the portion 28. Thus, the clips may also be made of a highly
resilient material.
[0020] As shown in FIG. 4, each clip 10 includes an upper
cantilevered leaf spring arm 34, a vertical arm 32, and a base 30.
In addition, the spring arm 34 includes a catch 36 which may be
turned downwardly relative to the arm 34. The arm 34 and base 30
may be substantially planar and substantially parallel to one
another, in one embodiment of the invention.
[0021] Similarly, the arms 22, 24, and 26 may include a guide end
38 which is adjacent to an opening 40. The opening 40 is engaged by
the catch 36 which is releasably locked to the strap 20 by the
guide end 38.
[0022] Referring next to FIG. 3, the strap arms 24 and 26 may be
hooked onto the clips 10a and lob so that the catches 36 of the
clips 10a, 10b engage the openings 40 in the spring arms 24 and 26.
The portion 28 is then rotated atop the heat sink 18. Thereafter,
the spring arm 22 is deflected downwardly until its guide end 38
engages the top of the catch 36 as shown in FIG. 4a.
[0023] Because of the downwardly deflected configuration of the
catch 36 this engagement causes the spring arm 34 to deflect
downwardly and the spring arm 22 to deflect inwardly as indicated
by the arrows in FIG. 4a Eventually the arms 34 and 22 slide past
one another, as shown in FIG. 4b. Then, the catch 36 springs
upwardly along the guide end 38. Eventually the catch 36 springs
through the opening 40 and the guide end 38 then springs outwardly
trapping the catch 36 in the opening 40, as shown in FIG. 4. The
catch 36 is releasably constrained on the side 41 of the guide edge
38. In this way, a spring clamping force may be applied by opposed
clips 10 to the strap 20 to securely press the heat sink 18 onto
the processor 11.
[0024] The securement between the clip 10c and the strap 20 may be
released by again depressing the spring arm 22, camming the catch
36 out of the opening 40 through the engagement of edge 44 with the
top surface of the catch 36. When the spring arm 22 is released, it
moves upwardly quickly, and the catch 36 does not reengage the
opening 40.
[0025] Turning now to FIG. 5, a tape 50, which may be made of a
relatively low cost material wound onto a reel (not shown),
includes a plurality of clips 10 secured in rows and columns
thereto. The clips 10 may be releasably secured to the tape 50
using a releasable adhesive.
[0026] The tape 50 may be unwound into a pick and place machine
(not shown) which sequentially engages the clips 10 and places them
in the correct positions on the circuit board 14. Thus, as shown in
FIG. 6, a pick and place machine vacuum grabber A may engage the
upper spring arm 34, lift the clip 10 off of the tape 50 and place
the clip 10 at the appropriate position on the circuit board 14.
Because of the horizontal, substantially planar configuration of
the spring arm 34, the vacuum grabber A has a good surface to
engage and lift the clip 10.
[0027] The pick and place machine vacuum grabber A may then place
the clip 10 on the circuit board 14 in positions precisely
preprogrammed into the pick and place machine. The base 30 of each
clip 10 is then positioned atop a solder pad 54 defined on the
circuit board 14, as shown in FIG. 7. The solder pad 54 may be
defined using conventional solder masking techniques.
[0028] Thereafter, the circuit board 14 may be processed in a
surface mount oven. All of the surface mount components on the
circuit board 14 are then heat secured using surface mount
technology to the circuit board 14. This means that the clips 10
are soldered to the circuit board 14. Alternatively, a heat
activatable adhesive may be used in place of a solder material.
[0029] In this way, strapping clips 10 may be positioned on circuit
boards in an automated, low cost fashion. The clips enable heat
sinks to be quickly strapped onto the socketed processors in cases
where clips are not provided with the sockets.
[0030] While the present invention has been described with respect
to a limited number of embodiments, those skilled in the art will
appreciate numerous modifications and variations therefrom. It is
intended that the appended claims cover all such modifications and
variations as fall within the true spirit and scope of this present
invention.
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