Title of Invention

ARRAYED FIN COOLING SYSTEM

Abstract An arrayed fin cooling system 100 for removing waste heat from a component 500 is disclosed. The arrayed fin cooling system 100 includes plurality of discrete cooling fins 10 that act as individual heat sinks. The cooling fins 10 are arranged in a radial array so that the cooling fins 10 diverge from one another to define an air path 39 between adjacent cooling fins 10. Each cooling fin 10 includes a base 31 that is adapted to connect with a surface 501 of the component 500 to be cooled. Waste heat is transferred from the component 500 to the cooling fin 10 via the base 31. The cooling fins 10 are surrounded at an outer edge 13 by a radial shield 50 that channels an air flow AF over the cooling fins 10 to maximize the amount of air that passes over the cooling fins 10. The cooling finslO can be manufactured at a low cost using processes such as stamping and forging.
Full Text ARRAYED FIN COOLER
FIELD OF THE INVENTION
The present invention relates generally to an arrayed fin cooling system for
removing heat from a component. More specifically, the present invention relates to
an arrayed fin cooling system that includes a plurality of discrete cooling fins
arranged in a radial array and with each of the cooling fins serving as a heat sink, so
that collectively, the cooling fins efficiently remove heat from the component.
BACKGROUND OF THE INVENTION
It is well known in the electronics art to place a heat sink in contact with an
electronic device so that waste heat generated by operation of the electronic device
is thermally transferred into the heat sink thereby cooling the electronic device. With
the advent of high clock speed electronic devices such as microprocessors (uP),
digital signal processors (DSP), and application specific integrated circuits (ASIC),
the amount of waste heat generated by those devices and the operating
temperature of those devices are directly proportional to clock speed. Therefore,
higher clock speeds result in increased waste heat generation which in turn
increases the operating temperature of the device. However, efficient operation of
the device requires that waste heat be effectively removed.
Heat sink devices came into common use as a preferred means for
dissipating waste heat from electronic devices such as the types described above.
In a typical application, a component to be cooled is carried by a connector that is
mounted on a PC board. Efficient dissipation of heat from the component by the
heat sink depends to a large extent on the thermal contact between the heat sink
and the component and the contact pressure between the heat sink and the
component. Ideally, an attachment device, such as a clip or the like, positions the
heat sink so that the a surface of the heat sink is in contact with the component and
so that the contact pressure between the heat sink and component acts along a load

axis that is centered on the component. Additionally, a fan is usually used to
generate an air flow through the heat sink so that waste heat in the heat sink is
thermally transferred from the heat sink to the air flow.
Heat sinks that are currently available on the market are manufactured using
prior machining processes that include extrusion, impact forging, and vacuum
brazing. A few heat sinks are produced using a die casting process. However, it is
difficult to produce a high performance heat sink using the die casting process. The
objective of all of those prior machining processes is to produce a heat sink having a
plurality of fins that are connected with a heat mass and that provide an air flow path
over the fins that will remove waste heat from the fins and the heat mass.
All of the aforementioned prior machining processes have their own
limitations on a Length to Breadth ratio (L/B) on a fin gap between adjacent fins on
the heat sink. Generally, in extruded heat sinks, efficiency depends on the number
of fins that can formed in a given area. To increase that area within a given volume,
the L/B ratio must be increased. Typically, the area is increased by decreasing the
fin gap between adjacent fins (i.e. B is reduced) and by increasing a height of the
fins (i.e. L is increased). However, the extrusion process has limitations on the L/B
*
ratio. That L/B ratio limitation paved a path for heat sinks to grow in size in a X-
direction and a Y-direction in order to cater to the high performance cooling needs of
the above mentioned high clock speed electronic devices.
One disadvantage to the prior machining processes is that a slit width that is
used to form an air gap between adjacent fins is parallel due to slitting wheels that
are used to machine the slits. As a result, a cross-sectional area of the fin is
reduced in a direction towards a center of the heat mass of the heat sink.
A second and related disadvantage to the prior machining processes is that a
fin depth is reduced with a subsequent reduction in a surface area of the fin that is
available to transfer the waste heat to the air flow over the fin.

A third disadvantage is that the number of fins that can be cut into the heat
mass is reduced. Therefore, there are fewer fins available to transfer the waste heat
from the fins to the air flow.
Finally, the prior machining processes can be complicated and can require
several machining steps that increase the cost of producing the heat sink. There are
many applications that use high clock speed electronic devices that also require a
low cost heat sink.
Consequently, there is a need for a heat sink that can be manufactured at a
low cost and without complex and time consuming machining processes. There is
also a need for a heat sink that can accommodate a large number of fins having a
large surface area. Additionally, there exists a need for a heat sink with deep fins
that have a large cross-sectional area at the heat mass.
SUMMARY OF THE INVENTION
The arrayed fin cooling system of the present invention solves the
aforementioned problems. The problems associated with manufacturing costs and
complexity are solved by using a plurality of discrete cooling fins to form an arrayed
fin cooling system. The discrete cooling fins can be manufactured at a low cost
using a process such as stamping, for example.
The problems associated with fin surface area and the number of fins are
solved by the discrete cooling fins because each cooling fin acts as a discrete heat
sink and the area of the fin can be made as large as is necessary for the intended
application. The number of cooling fins can be increased by decreasing a thickness
of each cooling fin.
Because the cooling fins define a heat mass of the arrayed fin cooling
system, a depth of the cooling fins is not limited by the machining processes used to
form the cooling fins. Therefore, the problems associated with the fins having a

larger cross-section area at the heat mass are solved by the using the discrete
cooling fins of the present invention.
Other aspects and advantages of the present invention will become apparent
from the following detailed description, taken in conjunction with the accompanying
drawings, illustrating by way of example the principles of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top profile view of an arrayed fin cooling system according to the
present invention.
FIG. 2 is a profile view of a discrete cooling fin according to the present
invention.
FIG. 3 is a profile view of a plurality of discrete cooling fins according to the
present invention.
FIG. 4 is a side profile view of an arrayed fin cooling system according to the
present invention.
FIG. 5 is a bottom profile view of a base ring prior to connection with an
arrayed fin cooling system according to the present invention.
FIGS. 6a and 6b are a bottom view and a bottom profile view respectively of a
base ring after connection with an arrayed fin cooling system according to the
present invention.
FIGS. 7a and 7b depict an air inflow and an air outflow through an arrayed fin
cooling system according to the present invention.

FIG. 8 is a profile view of a discrete cooling fin including a spacer according to
the present invention.
FIG. 9 is a profile view of a discrete cooling fin including a bent profile
according to the present invention.
FIGS. 10a through 10c depict variations in thickness of a discrete cooling fin
according to the present invention.
FIGS. 10d and 10e depict a cross-sectional profile of a discrete cooling fin
and an equidistance spacing between a plurality of cooling fins according to the
present invention.
FIGS. 11 and 12 are top plan view and a bottom plan view respectively of an
arrayed fin cooling system including a fan, a fan mounting ring, and a base plate
according to the present invention.
FIGS. 13 and 14 are side plan views depicting a bi-directional air flow through
an arrayed fin cooling system according to the present invention.
FIG. 15 is a cross-sectional view illustrating a hub radius of a fan according to
the present invention.
FIGS. 16a through 16e depict mounting a base ring with a base plate
according to the present invention.
FIG. 17 is a side profile view of an arrayed fin cooling system mounted in
contact with a component to be cooled according to the present invention.
FIGS. 18a through 18c are cross-sectional views depicting a bi-directional air
flow according to the present invention.

DETAILED DESCRIPTION
In the following detailed description and in the several figures of the drawings,
like elements are identified with like reference numerals.
As shown in the drawings for purpose of illustration, the present invention is
embodied in an arrayed fin cooling system for removing heat from a component.
The arrayed fin cooling system includes a plurality of discrete cooling fins. That is,
the arrayed fin cooling system comprises a plurality of individual cooling fins that are
combined to form the arrayed fin cooling system.
Each discrete cooling tin includes an inner edge, an outer edge, and cooling
surfaces that are positioned in opposition to each other and that are spaced apart by
a distance that decreases from the outer edge to the inner edge. Each discrete
cooling fin also includes a leading edge and a trailing edge. The cooling fins are
arranged in a radial array with the fins connected with one another along a portion of
their respective cooling surfaces that are proximate their respective inner edges.
The cooling fins diverge from one another in a radially outward direction so that an
air path is defined between adjacent cooling fins.
The trailing edge of each cooling fin includes a radial fin, a first
aerodynamically profiled surface, and a plurality of spaced apart cooling projections.
The cooling projections are positioned between the first aerodynamically profiled
surface and the inner edge of the cooling fin.
The leading edge of each cooling fin includes a base, a second
aerodynamically profiled surface, and a slot that is positioned between the base and
the second aerodynamically profiled surface. The base is placed into contact with
the component to be cooled so that heat is transferred from the component to the
cooling fin.

The arrayed fin cooling system also includes a base ring. The base ring
includes a collar profile that complements the slot on the cooling fins. The collar
profile is connected with the slot of each cooling fin and retains the cooling fins in
fixed relation to one another.
A radial shield is in contact with a portion of the outer edges of all the cooling
fins. The radial shield includes an upper edge and a lower edge that are separated
from each other by a distance. The radial shield defines an air inlet between the
lower edge and the second aerodynamically profiled surface and defines an air
outlet between the upper edge and the radial fin.
Heat is removed from the component by an air inflow through the air inlet.
The radial shield channels the air inflow through the air path and over the cooling
surfaces of the cooling fins. A portion of the air inflow is redirected over the cooling
projections by the first aerodynamically profiled surface. The radial shield also
channels the air inflow into an air outflow that exits through the air outlet and along
an axis that is substantially parallel with the inner edges of the cooling fins.
In FIGS. 1, 2 and 3, an arrayed fin cooling system 100 for removing heat from
a component (not shown) includes a plurality of discrete cooling fins 10. In FIG. 2,
each cooling fin 10 includes an inner edge 11, an outer edge 13, and cooling
surfaces 15 that are positioned in opposition to each other. The cooling surfaces 15
are spaced apart from each other by a distance that decreases from the outer edge
. 13 to the inner edge 11 as illustrated by a distance t0 at the outer edge 13 and a
distance t, at the inner edge 11 (i.e. t0 > tj). Each cooling fin 10 further includes a
leading edge 19 and a trailing edge 17. In FIG. 3, the cooling fins 10 are connected
with one another along a portion of their cooling surfaces 15 with their inner edges
11 positioned proximate to one another. The cooling fins 10 diverge from one
another in a radially outward direction r to define an air path 39 between adjacent
cooling fins 10. In FIG. 3, the air path 39 is narrower in a direction towards the inner
edge 11 as indicated by arrows 39b and 39c and is wider in a direction away from
the inner edge 11 as indicated by arrows 39a. FIG. 3 illustrates a sector of the

cooling fins 10 (four are shown); however, the arrayed fin cooling system 100 is
formed by adding additional fins in the manner shown in FIG. 1.
Tne trailing edge 17 includes a radial fin 21, a first aerodynamically profiled
surface 23, and a plurality of cooling projections 25 that are positioned between the
first aerodynamically profiled surface 23 and the inner edge 11. The cooling
projections 25 are spaced apart from one another by a distance Sp. The distance
Sp between the cooling projections 25 can be the same such that the cooling
projections 25 are equidistantly spaced apart from one another or the distance Sp
between the cooling projections 25 can vary among the cooling projections 25. The
first aerodynamically profiled surfaces 23 defines a chamber 61 that surrounds the
cooling projections 25.
The cooling fins 10 can be formed using a variety of processes including but
not limited to stamping, forging, die casting, and profile extrusion plus stamping. For
thin cooling fins (e.g. to is less than about 0.5 millimeters) sheet extrusion and
stamping can be used to form the cooling fins 10. By contrast, for thick cooling fins
a process such as die casting or forging can be used to form the cooling fins 10.
The use of thinner cooling fins 10 allows for a greater number of the cooling fins 10
to be arrayed with one another; whereas, the use of thicker cooling fins 10
decreases the number of the cooling fins 10 that can be arrayed with one another.
Suitable materials for the cooling fins 10 include but are not limited to
aluminum (Al) and alloys of aluminum, copper (Cu) and alloys of copper, gold (Au),
or any material that has a good thermal conductivity and that is press workable.
The leading edge 19 includes a base 31, a second aerodynamically profiled
surface 33, and a slot 35 that is positioned between the base 31 and the second
aerodynamically profiled surface 33. The base 31 is adapted to connect with the
component (not shown) so that heat in the component is transferred from the
component to the cooling fin 10 via the base 31. Contact between the base 31 and
the component can be by direct contact or by intermediate contact. For instance, a

thermal interface material (not shown) between the base 31 and the component can
be used to effectuate the intermediate contact. In either case, the connection
provides for thermal communication of heat from the component to the base 31.
The base 31 can have a surface profile that complements a surface of the
component that the base 31 is to be placed in contact with. Preferably, the base 31
has a substantially planar surface profile (i.e. it is substantially flat). A flat surface for
the base 31 is amendable to mounting the base 31 on a component having a
substantially flat surface, such as a microprocessor, for example.
The first aerodynamically profiled surface 23 and the second aerodynamically
profiled surface 33 can be complex surface profiles that include but are not limited to
a profile that is a sloped profile, an arcuate profile, a planar profile, or any
combination of those profiles. For instance, in FIG. 2, the first aerodynamically
profiled surface 23 includes a planar profile that is substantially parallel with the
outer edge 13 and extending from the radial fin 21 and then blending with a sloped
profile which in turn blends with an arcuate profile that terminates at an outermost of
the cooling projections 25. Similarly, the second aerodynamically profiled surface 33
includes a planar profile that blends with an arcuate profile which in turn blends with
the outer edge 13.
When the cooling fins 10 are arranged in a radial array as illustrated in FIGS.
3 and 4, the slot 35 defines a groove 37 between the base 31 and the second
aerodynamically profiled surface 33. In FIG. 5, a base ring 71 includes a collar
profile 73 that complements the slot 35. Accordingly, the collar profile 73 also
complements the groove 37. In FIGS. 6a and 6b, the collar profile 73 is in contact
with the slot 35 of all of the cooling fins 10 and retains the cooling fins 10 in fixed
relation with one another.
Preferably, the base ring 71 includes a first split ring 75a and a second split
ring 75b that are connected with each other by one or more fasteners 77. The first
and second split rings (75a, 75b) include the collar profile 73 and are designed to
clamp the cooling fins 10 in fixed relation with one another. A variety of fasteners 77

can be used to connect the first and second split rings (75a, 75b) with each other.
For instance, a nut and bolt or a screw can be used. A portion of the first and
second split rings (75a, 75b) can be machined to include threads for receiving a
machine screw, for example. Prioi to attaching the first and second split rings (75a,
75b), the cooling fins 10 are bundled together and then the first and second split
rings (75a, 75b) are used to clamp the bundled cooling fins together. Although
welding, vacuum brazing, or another joining process can be used to hold the cooling
fins 10 in fixed relation with one another, those processes are not required.
Consequently, an unnecessary and potentially costly manufacturing step (i.e.
welding or the like) is eliminated, and if necessary, the first and second split rings
(75a, 75b) can be removed to repair one or more cooling fins 10 or to refurbish a
damaged arrayed fin cooling system 100. However, if ft is desirable to permanently
connect the cooling fins 10 to one another, then welding, vacuum brazing, or the like
can be used to effectuate the permanent connection. A fastener including but not
limited to a screw, a nut and bolt, a lock pin, and interlock profiles can be used to
connect the first and second split rings (75a, 75b) with each other.
In FIGS. 2 and 3, an innermost of the cooling projections 25 (i.e. the cooling
projections 25 closest to the inner edge 11) can include an inset portion 27 that is
adapted to receive at least one fastener (not shown). The fastener is in contact with
the inset portion 27 and retains the cooling fins 10 in fixed relation with one another.
The fastener can be used in conjunction with the above mentioned base ring 71 to
retain the cooling fins 10 in fixed relation with one another. When the cooling fins 10
are arranged in a radial array, the inset portion 27 of all the innermost of the cooling
projections 25 will define a groove (see FIG. 3) and the fastener can be clamped
around the groove to hold the cooling fins 10 in fixed relation with one another.
Examples of fasteners that can be used include but are not limited to a c-clip and a
clipping ring.
In FIG. 1, a radial shield 50 includes an upper edge 55 and a lower edge 57
that are separated from each other by a distance Ds. The radial shield 50 is in
contact with a portion of the outer edge 13 of all the cooling fins 10 (i.e. the radial
shield 50 spans a portion of the outer edge 13). Moreover, the radial shield 50

defines an air inlet 51 between the lower edge 57 and the second aerodynamically
profiled surface 33 and defines an air outlet 53 between the upper edge 55 and the
radial fin 21. The radial shield 50 can be a sheet of material or a contiguous band of
material, that surrounds the outer edges 13 of the cooling fins 10.
In FIGS. 7a and 7b, heat is removed from the component (not shown) by an
air inflow As through the air inlet 51. The air inflow As can enter the air inlet 51 from
a combination of directions including horizontal and vertical (as shown) or at an
angle. As the air inflow Ai moves from the air inlet 51 and into the air paths 39
between the cooling fins 10 (see FIG. 3) the radial shield 50 channels the air inflow
Ai through the air path 39 and over the cooling surfaces 15 so that heat conducted
through the base 31 is transferred to the air inflow Ai. Furthermore, the first
aerodynamically profiled surface 23 provides a smooth change over direction for the
air inflow As such that it redirects a portion of the air inflow Ai over the cooling
projections 25 as denoted by dashed arrows Ai. As a result, additional heat is
transferred from the cooling projections 25 to the air inflow A(. The radial shield 50
also channels the air inflow Aj into an air outflow A0 that exits the arrayed fin
cooling device 100 through the air outlet 53 and along an axis Y that is substantially
parallel with the inner edges 11 of the cooling fins 10 (see FIGS. 2 and 3). The air
outflow A0 passes over the radial fins 21. to further dissipate heat from the cooling
fins 10.
Without the radial shield 50, air could enter anywhere along the air path 39
and the amount of the air inflow A{ that passes over the cooling surfaces 15 would
be reduced with a resulting decrease in heat transfer from the cooling fins 10 to the
air inflow Aj. Moreover, without the radial shield 50, the air inflow A.,, over the
cooling projections 25 would be significantly reduced with a resulting decrease in
heat transfer from the cooling projections 25.
Because the radial shield 50 guides the air flow from the air inlet 51 to the air
outlet 53 (or vice-versa) the distance Ds should be selected to leave an area

sufficient for the air inflow A( via the air inlet 51 and the air outflow A; via the air
outlet 53. Therefore, in FIG. 7a. a distance D0 between the radial fin 21 and the
upper edge 55 and a distance Dj between the second aerodynamically profiled
surface 33 and the lower edge 57 can be from about 3.0 millimeters to about 10.0
millimeters, for example. The actual distances for D0, Dj, and Ds will vary based on
application and are not limited to the example distances listed herein.
One advantage of the present invention is that each of the cooling fins 10 is a
discrete heat sink that connects with the component to be cooled at the base 31 and
transfers heat from the component to the air inflow A; and the air outflow AQ.
Consequently, the amount of heat transferred from the component to the arrayed fin
cooling device 100 depends in part on the number of cooling fins 10 that are
connected with one another as described above. Moreover, the amount of heat
transferred can be increased or decreased by increasing or decreasing the number
of cooling fins 10 respectively.
Preferably, the cooling fins 10 are spaced apart from one another by an equal
distance. In FIG. 8, an equidistant spacing between adjacent cooling fins 10 can be
accomplished using a spacer 32 that is connected with the outer edge 13 of each
cooling fin 10. The spacer 32 extends outward of a selected one of the cooling
surfaces 15 by a predetermined height hv When the cooling fins 10 are arranged in
a radial array as illustrated in FIGS. 6b and 10d, the spacer 32 of each cooling fin 10
is in contact with the cooling surface 15 of an adjacent cooling fin 10 and the
predetermined height h1 defines the equidistant spacing between adjacent cooling
fins 10.
*
Preferably, the spacer 32 is integrally formed with the cooling fin 10 and is
bent at an angle with respect to the cooling surface 15 such that the spacer 32
extends outward of the cooling surface 15 by the height hv By contrast, the spacer
32 can be a separate compbnent that is fixedly connected with the cooling surface
15. If the spacer 32 is a separate component, then it should be heat resistant so

that it will not deform or fail due to heat being conducted through the cooling fins 10.
A material such as a metal, a ceramic, or plastic can be used for the spacer 32, for
example. The spacer 32 can be connected with the cooling surface 15 by gluing or
welding, for example. After the cooling fins 10 have been arranged in a radial array
as illustrated in FIGS. 6b, the radial shield 50 can be connected with the outer edges
13 of the cooling fins 10 as was described above (see FIG. 7a).
In one embodiment of the present invention, as illustrated in FIG. 9, each
cooling fin 10 includes a bent profile 22 that is in contact with the outer edge 13.
The bent profile 22 includes a first edge 24 and a second edge 26 that are
separated by a first width Wp. The bent profile 22 extends outward of a selected
one of the cooling surfaces 15 by a profile height h2. When the cooling fins 10 are
arranged in a radial array as illustrated in FIGS. 3 and 7b, the bent profile 22 of each
cooling fin 10 is in contact with the cooling surface 15 of an adjacent cooling fin 10
so that the bent profiles 22 of all the cooling fins 10 defines the radial shield 50, the
air outlet 53 is defined between the first edge 24, and the radial fin 21 and the air
inlet 51 is defined between the second edge 26 and the second aerodynamically
profiled surface 33. The first width Wp can be identical to the distance Ds between
the upper and lower edges (55, 57) of the radial shield 50.
In another embodiment of the present invention, the bent profile 22 operates
to space the cooling fins 10 apart from one another by an equal distance.
Essentially, the profile height h2 serves as a spacer that equidistantly spaces
adjacent cooling fins 10 apart from each other (see FIG. 10e).
The air path 39 between adjacent cooling fins 10 can be defined by the
spacer 32 or the bent profile 22 as illustrated in FIGS. 3,10d, and 10e. Because the
air path 39 is narrower in a direction towards the inner edge 11 and is wider in a
direction away from the inner edge 11 (see FIG. 3), a greater percentage of the air
inflow A, passes through the wider air paths (39 and 39a) than through the narrower
air paths (39b and 39c). Although the actual amount of air flow through those air
paths is difficult to quantify and will vary based on application, approximately 80% to

85% of the air flow can flow through the wider air paths (39 and 39a) and
approximately 15% to 20% of the air flow can flow through the narrower air paths
(39b and 39c).
In FIGS. 11 through 13, the aforementioned air inflow A, can be generated by
a fan 200 that is connected with the cooling fins 10. The fan 200 can include a fan
housing 205 that is in contact with to the cooling fins 10, a fan hub 201 that carries a
rotor 207 having a plurality of fan blades 203 connected therewith. The fan 200 can
generate an air flow AF that creates a low pressure region within the chamber 61
that generates the air inflow A,.
In FIG. 14, the direction of the air flow Ap is reversed from that of FIG. 13 and
the air inflow A, and the air outflow AQ are also reversed. The air flow Ap is into the
chamber 61. Accordingly, the air inflow Aj enters the cooling fins 10 via the air
outlet 53 and the air outflow AQ exits the cooling fins 10 via the air inlet 51.
Therefore, another advantage of the arrayed fin cooling system 100 of the
present invention is that it can effectuate heat transfer from the cooling fins 10 to the
air inflow Aj with a bi-directional air flow Ap. The fan 200 can either pull air through
the cooling fins 10 as illustrated by the air-flow Ap in FIG. 13 or push air through the
cooling fins 10 as illustrated by the air flow AF in FIG. 14.
In FIGS. 18a through 18b, bi-directional movement of the air inflow A, over
the cooling surface 15 is illustrated for the air flow Ap when air is pulled through the
arrayed fin cooling system 100 (i.e. a pull air flow) and for the air flow Ap when air is
blown into the arrayed fin cooling system 100 (i.e. a push air flow). The air flow Ap
can be from an external source or from a fan connected with the arrayed fin cooling
system 100 as described above.

FIGS. 18b and 18c are cross-sectional views along line AA of FIG. 18a. In
FIG. 18b, the air flow AF pulls air through the arrayed fin cooling system 100 and the
air inflow Aj enters the air path 39 via the air inlet 51 and passes over the cooling
surfaces 15 (see dashed arrows). The first aerodynamically profiled surface 23
redirects a portion of that air inflow Aj into the air inflow A,-, that wets over the
cooling projections 25 (see arrows Ah). The air inflows (A,, A^) exit the arrayed fin
cooling system 100 as the air outflow AQ with a portion of the air outflow A0 exiting
via the air outlet 53.
Similarly, in FIG. 18c, when the air flow AF is in the opposite direction (i.e. air
is blown or pushed into the arrayed fin cooling system 100), a portion of the air
inflow Aj enters the air path 39 via the air outlet 53 and passes over the cooling
surfaces 15 (see dashed arrows). The first aerodynamically profiled surface 23
redirects a portion of that air inflow Aj into the air inflow A(1 that wets over the
cooling projections 25 (see arrows A(1). The air inflows (A;, A(1) exit the arrayed fin
cooling system 100 as the air outflow A0 which exit via the air inlet 51.
The radial fin 21 of each cooling fin 10 can include a seating surface 38 (see
FIGS. 3 and 10a) for mounting the fan 200 with the cooling fins 10. Preferably, the
seating surface 38 has a surface profile that complements a profile of the fan
housing 205. For instance, the fan housing 205 can have a planar surface and the
seating surface 38 can be a substantially planar surface so that the fan housing 205
can be mounted with the seating surface 38 as illustrated in FIG. 11.
In FIGS. 3, 6a and 6b, the cooling fins 10 can include a lip 36 that extends
outward of the outer edge 13 and is positioned below the seating surface 38 of the
radial fin 21. In FIGS. 11 through 13,a fan mounting ring 300 is positioned adjacent
to the lip 36 and a fastener 209 is used to connect the fan mounting 300 ring with
the fan 200 and for urging the fan mounting ring 300 into contact with the lip 36 so
that the fan 200 is fixedly mounted on the seating surface 38. The fastener 209 can
be a screw or a nut and bolt, for example.

In one embodiment of the present invention, as illustrated in FIGS. 8 and 15,
the cooling projections 25 are positioned within a predetermined radial distance RD
from the axis Y or from the inner edge 11. The predetermined radial distance RD
can be selected based on a hub radius RH of a fan. For instance, in FIG. 15, if the
hub 207 of the fan 200 has a hub radius RH, then the predetermined radial distance
R0 will be less than or equal to the hub radius RH (that is: RD when the fan 200 is mounted to the cooling fins 10, all of the cooling projections 25
including an outermost oi the cooling projections 25 will be positioned within the hub
radius RH. One disadvantage to prior cooling devices is noise generated by air
turbulence and air shock losses caused by an air flow from a fan. By restricting the
radial position of the cooling projections 25 to be within the predetermined radial
distance RD, the cooling projections 25 will not come under a swept area 203a of the
fan blades 203 thereby reducing air turbulence and obstructions to air flow within the
chamber 61. As a result, less noise is generated by the arrayed fin cooling system
100 of the present invention. Reduced noise levels are highly desirable in portable
PC's and in desktop PC's. An additional benefit of restricting the radial position of
the cooling projections 25 to be within the predetermined radial distance RD is that
the reduced turbulence allows the air inflow A1f to pass over the cooling projections
25 thereby enhancing heat transfer from the cooling fins 10.
The predetermined radial distance RD and the number of cooling projections
25 will vary based on the application and on the hub radius RH. However, as an
example, if the predetermined radial distance RD is about 17.5 millimeters, then
there can be 3 to 5 of the cooling projections 25 within the predetermined radial
distance RD. #
As mentioned above, the cooling surfaces 15 are spaced apart from each
other by a distance that decreases from the outer edge 13 to the inner edge 11 (i.e.
to > tj). The distance (t0,tj) can be continuously variable from the outer edge 13 to
the inner edge 11. Preferably, the distance t0 is substantially constant for a
distance d0 from the outer edge 13 and then the distance between the cooling

surfaces 15 decreases to X, at the inner edge 11 as illustrated in the cooling surfaces
15. For instance, t0 can be 1.60 millimeters and t, can be 0.5 millimeters.
In FIGS. 10b and 10c, a cross-sectional view along line aa of the cooling fin
10 of FIG. 10b illustrates the decreasing distance between the cooling surfaces 15
from the outer edge 13 to the inner edge 11. The distance t0 is substantially
constant for the distance d0 from the outer edge 13. Thereafter, the distance
between the cooling surfaces 15 decreases to tj at the inner edge. Accordingly, a
variation in the distance between the opposed cooling surfaces 15 defines a cross-
sectional profile of the cooling fin 10. The cross-sectional profile can include a
sloped profile, a wedge profile, an equilateral triangle, and a right triangle. In FIG.
10b. the cross-sectional profile is that of a right triangle and in FIG. 10c the cross-
sectiona! profile is that of an equilateral triangle. As a point of reference, the right
triangle and the equilateral triangle have a base at a point indicated by dashed line
b. The sloped profile and the wedge profile can be variations on the cross-sectional
profiles of the right triangle and the equilateral triangle.
The cooling fin 10 should be as close to zero thickness as is possible at the
inner edge 11 (that is tj s 0). But a zero thickness is not practically possible;
therefore, the cooling fin 10 should be as thin as possible at the inner edge 11.
Preferably, the cooling fin 10 has a thickness tj at the inner edge 11 that is about
0.07 millimeters or less.
In FIGS. 10b and 10c, the cooling fin 10 can have a taper angle 9 measured
between the cooling surfaces 15. The taper angle 8 applies to the aforementioned
cross-sectional profiles and the taper angle 8 can include a wide range of angles
that will be determined by the application. For example, if the taper angle 8 is 2.0
degrees, then 180 of the cooling fins 10 can be mounted in the arrayed fin cooling
system 100 (that is: 360 degrees -=- 2.0 degrees = 180). As another example, if the
taper angle 8 is 6.0 degrees, then 60 of the cooling fins 10 can be mounted in the

arrayed fin cooling system 100 (that is: 360 degrees -=- 6.0 degrees = 60).
Preferably, the taper angle 0 is in a range from about 2.0 degrees to about 6.0
degrees. The taper angle 8 can also determine the spacing between adjacent
cooling fins that defines the air paths (39, 39a, 39b, 39c) and the amount of air flow
through those air paths.
As was described above, the amount of waste heat that can be dissipated by
the arrayed fin cooling system 100 is partially dependent on the number of cooling
fins 10 that are contained within the arrayed fin cooling system 100. The amount of
waste heat is also dependent on a contact area of the component to be cooled that
is in contact with the base 31 of all the cooling fins 10. For example, to dissipate
about 60.0 W of waste heat from a component having a contact area of 30 mm »30
mm. the arrayed fin cooling system 100 would need approximately 72 cooling fins
10.
As a further example, with an outside diameter of about 64.0 mm measured
across the radial shield 50 and a height of about 38.0 mm measured from the base
31 to the planar surface 38, the arrayed fin cooling system 100 has a performance
factor of about 0.26 C7Watt.
In FIGS. 10d and 10e, the cooling fins 10 are connected with one another
along a portion of their cooling surfaces 15 with their inner edges 11 positioned
proximate to one another such that the cooling fins 10 diverge from one another in a
radially outward direction to define the air path 39 between adjacent cooling fins 10.
The spacer 32 or the bent profile 22 can be used to equidistantly space adjacent
cooling fins 10 apart from each other.
In FIGS. 6a and 6b, the base ring 71 can include a plurality of key profiles 79
positioned on the first and second split rings (75a, 75b). The key profiles 79 are
adapted to facilitate mounting of the base ring 71 with a base plate 400 as illustrated
in FIGS. 16a through 16c. The base plate 400 includes a mounting surface 401, a
base surface 403, and an aperture 404 having a profile that complements the base
ring 71. That is, the aperture 404 has a shape that complements a shape of the

base ring.71. The aperture 404 further includes a plurality of lock profiles 406 that
complement the key profiles 79 of the first and second split rings (75a, 75b).
Preferably, the base plate 400 is a planar materia! and the mounting surface 401
and the base surface 403 are opposed surfaces that are substantially parallel to
each other.
In FIG. 16a the base ring 71 is positioned on the mounting surface 401 with
the key profiles 79 aligned with their respective lock profiles 406 so that the base
ring 71 can be inserted through the aperture 404 and so that the second
aerodynamically profiled surface 33 (not shown) is in contact with the mounting
surface 401. In FIG. 16b, the key profiles 79 are positioned in alignment with their
respective lock profiles 406 so that the base ring 71 can be pushed through the
aperture 404.
In FIG. 16c, the key profiles 79 are aligned with their respective lock profiles
406 and are positioned such that they surpass the base surface 403 (i.e. they are
above the base surface 403). The base ring 71 then is twisted (see dashed arrow T)
to rotate the key profiles 79 into engagement with the base surface 403 such that
the base ring 71 is removably locked with the base plate 400, as illustrated in FIG.
16d. Removal of the base ring 71 is the reverse of insertion.
In FIG. 16e, after insertion, a portion of the second aerodynamically profiled
surface 33 can remain in contact with the mounting surface 401. In FIGS. 16a
through 16d, the arrayed fin cooling system 100 is not shown for purposes of
illustrating insertion and removal of the base ring 71 in the base plate 400; however,
the steps set forth above in reference to FIGS. 16a through 16d apply with the
arrayed fin cooling system 100 already mounted in the base ring 71.
The base plate 400 can include a plurality of through holes 407 for connecting
a fastener or the like to the base plate 400 to allow for connecting the base plate
400 with a substrate such as PC board or with a connector such as a PGA
connector. The base plate 400 can be made from a variety of rigid materials
including metals, plastic, and composites. For example, aluminum (Al) can be used

In FIG. 17. a fastener 421 that includes a spring 425 and a threaded shank
423 is inserted in'the through holes 407. A component 500 to be cooled by the
arrayed fin cooling system 100 is carried by a substrate 600. The substrate 600 can
be a PC board or a PGA connector, for example. The substrate 600 can have
threaded holes (not shown) for receiving the threaded shank 423 of the fastener
421. With the base plate 400 mounted with the substrate 600. the base 31 of the
cooling fins 10 is positioned in contact with a surface 501 of the component 500.
Preferably, the base plate positions the axis Y in coaxial alignment with a center axis
C of the component 500. The springs 425 are operative to exert a contact force
beiween the component 500 and the base 31 thereby reducing contact resistance
so that heat is effectively and efficiently transferred from the component surface 501
to the base 31. Preferably, the contact force acts along the axes (Y, C). That is, the
contact force is coaxial with the axes (Y, C).
Although several embodiments of the present invention have been disclosed
and illustrated, the invention is not limited to the specific forms or arrangements of
parts so described and illustrated. The invention is only limited by the claims.

What is Claimed is: —
1. An arrayed fin cooling system 100 for removing heat from a component 500,
comprising:
a plurality of discrete cooling fins 10, wherein each discrete cooling fin 10
includes an inner edge 11, an outer edge 13, opposed cooling surfaces 15 that are
spaced apart by a distance (t0, tj) that decreases from the outer edge 13 to the inner
edge 11, a leading edge 19, and a trailing edge 17,
the cooling fins 10 are connected with one another along a portion of their
cooling surfaces 15 with their inner edges 11 positioned proximate to one another such
that the cooling fins 10 diverge from one another in a radially outward direction r to
define an air path 39 between adjacent cooling fins 10,
wherein the trailing edge 17 includes a radial fin 21, a first aerodynamically
profiled surface 23, and a plurality of spaced apart cooling projections 25 positioned
between the first aerodynamically profiled surface 23 and the inner edge 11, and
wherein the leading edge 19 includes a base 31 adapted to connect with the
component 500 so that heat is transferred from the component 500 to the cooling fin
10, a second aerodynamically profiled surface 33, and a slot 35 positioned between the
base 31 and the second aerodynamically profiled surface 33;
a base ring 71 including a collar profile 73 that complements the slot 35, the
collar profile 73 is in contact with the slot 35 of each cooling fin 10 and retains the
cooling fins 10 in fixed relation with one another; and
a radial shield 50 including an upper edge 55 and a lower edge 57 separated by
a distance Ds, the radial shield 50 is in contact with a portion of the outer edges 13 of

the cooling fins 10, and the radial shield 50 defines an air inlet 51 between the lower
edge 57 and the second aerodynamically profiled surface 33 and defines an air outlet
53 between the upper edge 55 and the radial fin 21, and
wherein heat is removed from the component 500 by an air inflow A, through the
air inlet 51, the radial shield 50 channels the air inflow Aj through the air path 39 and
over the cooling surfaces 15, the first aerodynamically profiled surface 23 redirects a
portion A^ of the air inflow Aj over the cooling projections 25, and the radial shield 50 is
operative to channel the air inflow Aj into an air outflow AQ that exits through the air
outlet 53 and along an axis Y that is substantially parallel with the inner edges 11.
2. The arrayed fin cooling system 100 as set forth in Claim 1, wherein the cooling
fins 10 are equidistantly spaced apart from one another by a spacer 32 connected with
the outer edge 13 of each cooling fin 10, the spacer 32 extends outward of a selected
one of the cooling surfaces 15 by a predetermined height h1( and the spacer 32 is in
contact with the cooling surface 15 of an adjacent cooling fin 10.
3. The arrayed fin cooling system 100 as set forth in Claim 1, wherein each cooling
fin 10 includes a bent profile 22 in contact with the outer edge 13, the bent profile 22
extends outward of a selected one of the cooling surfaces 15 by a profile height h2, and
the bent profile 22 includes a first edge 24 and a second edge 26 separated by a first
width Wp, and
wherein the bent profile 22 is in contact with the cooling surface 15 of an
adjacent cooling fin 10 so that the radial shield 50 is defined by the bent profiles 22 of
all the cooling fins 10 and the air outlet 53 is defined between the first edge 24 and the
radial fin 21 and the air inlet 51 is defined between the second edge 26 and the second
aerodynamically profiled surface 33.

4. The arrayed fin cooling system 100 as set forth in Claim 3, wherein the cooling
fins 10 are equidistantly spaced apart from one another by the bent profile 22.
5. The arrayed fin cooling system 100 as set forth in Claim 1 and further comprising
a fan 200 connected with the cooling fins 10 and operative to generate the air inflow Aj.
6. The arrayed fin cooling system 100 as set forth in Claim 5, wherein the fan 200
generates an air flow Ap selected from the group consisting of a pull air flow and a push
air flow.
7. The arrayed fin cooling system 100 as set forth in Claim 5, wherein the radial fin
21 includes a seating surface 38 for mounting the fan 200 with the cooling fins 10.
8. The arrayed fin cooling system 100 as set forth in Claim 7 and further
comprising:
a lip 36 extending outward of the outer edge 13 and positioned below the seating
surface 38 of the radial fin 21;
a fan mounting ring 300 positioned adjacent to the lip 36; and
a fastener 209 for connecting the fan mounting ring 300 with the fan 200 and for
urging the fan mounting ring 300 into contact with the lip 36 so that the fan 200 is
fixedly mounted on the seating surface 38.
9. The arrayed fin cooling system 100 as set forth in Claim 1, wherein a variation in
the distance (t0, t,) between the opposed cooling surfaces 15 defines a cross-sectional
profile selected from the group consisting of a sloped profile, a wedge profile, an
equilateral triangle, and a right triangle.

10. The arrayed fin cooling system 100 as set forth in Claim 1, wherein an innermost
of the cooling projections 25 includes an inset portion 27 adapted to receive at least
one fastener and the fastener is connected with the inset portion 27 and is operative to
retain the cooling fins 10 in fixed relation to one another.
11. The arrayed fin cooling system 100 as set forth in Claim 1, wherein the cooling
projections 25 are positioned within a predetermined radial RD distance from a selected
one of the axis Y or the inner edge 11.
12. The arrayed fin cooling system 100 as set forth in Claim 11, wherein the
predetermined radial distance RD is determined by a hub radius RH of a fan.
13. The arrayed fin cooling system 100 as set forth in Claim 1, wherein the first
aerodynamically profiled surface 23 and the second aerodynamically profiled surface
33 have a profile that is a selected one or more of a sloped profile, an arcuate profile,
and a planar profile.
14. The arrayed fin cooling system 100 of Claim 1, wherein heat is removed from the
component 500 by an air inflow A, through the air outlet 53, the radial shield 50
channels the air inflow A, through the air path 39 and over the cooling surfaces 15, the
first aerodynamically profiled surface 23 redirects a portion A,n of the air inflow A, over
the cooling projections 25, and the radial shield 50 is operative to channel the air inflow
A, into an air outflow AQ that exits through the air inlet 51 and along an axis Y that is
substantially parallel with the inner edges 11.
15. The arrayed fin cooling system 100 of Claim 1, wherein the base ring 71
comprises a first split ring 75a and a second split ring 75b that are connected with each
other by at least one fastener 77 and the first and second split rings (75a, 75b) are
operative to clamp the cooling fins 10 in fixed relation with one another.

16. The arrayed fin cooling system 100 of Claim 15 and further comprising
a plurality of key profiles 79 positioned on the first split ring 75a and on the
second split ring 75b; and
a base plate 400 including a mounting surface 401, a base surface 403, and an
aperture 404 extending between the mounting and base surfaces (401, 403) and
having a profile that complements the base ring 71, the aperture 404 including a
plurality of lock profiles 406 that complement the key profiles 79, and
wherein the base ring 71 is mounted with the base plate 400 by aligning the key
profiles 79 with the lock profiles 406 and inserting the base ring 71 through the aperture
404 so that the second aerodynamically profiled surface 33 is in contact with the
mounting surface 401 and then twisting the base ring 71 to rotate the key profiles 79
into engagement with the base surface 403 to removably lock the base ring 71 with the
base plate 400.

An arrayed fin cooling system 100 for removing waste heat from a component
500 is disclosed. The arrayed fin cooling system 100 includes plurality of discrete
cooling fins 10 that act as individual heat sinks. The cooling fins 10 are arranged in a
radial array so that the cooling fins 10 diverge from one another to define an air path 39
between adjacent cooling fins 10. Each cooling fin 10 includes a base 31 that is
adapted to connect with a surface 501 of the component 500 to be cooled. Waste heat
is transferred from the component 500 to the cooling fin 10 via the base 31. The
cooling fins 10 are surrounded at an outer edge 13 by a radial shield 50 that channels
an air flow AF over the cooling fins 10 to maximize the amount of air that passes over
the cooling fins 10. The cooling finslO can be manufactured at a low cost using
processes such as stamping and forging.

Documents:

617-CAL-2002-(22-03-2012)-CORRESPONDENCE.pdf

617-CAL-2002-(22-03-2012)-PA-CERTIFIED COPIES.pdf

617-CAL-2002-ABSTRACT 1.1.pdf

617-cal-2002-abstract.pdf

617-CAL-2002-CLAIMS 1.1.pdf

617-cal-2002-claims.pdf

617-CAL-2002-CORRESPONDENCE 1.1.pdf

617-cal-2002-correspondence.pdf

617-CAL-2002-DESCRIPTION (COMPLETE) 1.1.pdf

617-cal-2002-description (complete).pdf

617-CAL-2002-DRAWINGS 1.1.pdf

617-cal-2002-drawings.pdf

617-cal-2002-examination report.pdf

617-CAL-2002-FORM 1.1.1.pdf

617-cal-2002-form 1.pdf

617-cal-2002-form 13.pdf

617-cal-2002-form 18.pdf

617-CAL-2002-FORM 2.1.1.pdf

617-cal-2002-form 2.pdf

617-CAL-2002-FORM 3.1.1.pdf

617-cal-2002-form 3.pdf

617-cal-2002-form 5.pdf

617-CAL-2002-FORM-27.pdf

617-cal-2002-gpa.pdf

617-CAL-2002-OTHERS.pdf

617-CAL-2002-PA.pdf

617-CAL-2002-PETITION UNDER RULE 137.pdf

617-cal-2002-priority document.pdf

617-cal-2002-translated copy of priority document.pdf


Patent Number 243407
Indian Patent Application Number 617/CAL/2002
PG Journal Number 43/2010
Publication Date 22-Oct-2010
Grant Date 13-Oct-2010
Date of Filing 28-Oct-2002
Name of Patentee HEWLETT-PACKARD COMPANY
Applicant Address 3000 HANOVER STREET, PALO ALTO, CALIFORNIA
Inventors:
# Inventor's Name Inventor's Address
1 HEGDE SHANKAR 17-81, KRISHNA NAGAR, ANNASSANDRAPALYA, BANGALORE-560017, KARNATKA, INDIA
PCT International Classification Number F28F 7/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 09/999562 2001-10-31 U.S.A.