Fan for cooling computer

A ventilating device is provided for ventilating an electronic apparatus such as a computer. The device includes a housing having a top wall with a first ventilating aperture therein, and further includes a floor, a pair of side walls extending between said floor and said top wall, and an end wall closing one end of the housing. The housing is open at one end. The device further includes a fan unit secured in the housing adjacent the top wall in substantial alignment with the ventilating aperture and spaced above the housing floor, whereby the fan unit pulls air in through one of the ventilating aperture and open end expels air through the other thereof to facilitate the flow of air through the electronic apparatus.

BACKGROUND OF THE INVENTION 
Some popular computers that are used extensively both in business and in 
the home rely upon convection cooling. While the electronic components of 
these computers are all solid state, they still generate some amount of 
heat. However, considerable additional heat is generated by the power 
supply and by a motor for a disk drive which is also often included. 
Actual temperatures of the interior of these computers can reach 
170.degree. F. or more. Heat is damaging to integrated circuits and other 
modern electronic components and leads to shortened service life of 
components and reduced reliability of the computer or other apparatus 
utilizing such components. 
OBJECTS AND SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a device for use with a 
convection-cooled computer or other electronic device to provide 
forced-air ventilation and improved cooling of the computer or other 
apparatus. 
More particularly, the present invention provides a device that mounts 
adjacent an area of a computer or other apparatus which is normally used 
as an inlet or outlet for convection cooling, and moves air through the 
interior of the computer or other apparatus. 
At least one popular computer model has a molded plastic enclosure that has 
a handle formed as an integral part of the top of the enclosure. There is 
an opening beneath the handle for the exit of warm air that rises to the 
top of the enclosure. Additional air inlet openings are provided elsewhere 
in the enclosure for enabling a current of air to convectively cool the 
components of the computer. In accordance with a preferred form of the 
present invention, a ventilating device is provided which fits into the 
top of the computer, under its handle. 
The ventilating device has a top wall with aperture means therein. It has a 
bottom wall and a pair of side walls extending between the top and bottom 
walls. It further has a pair of end walls, with the first end wall closing 
one end of said housing and the second end wall having aperture means 
therein. The device further has a fan unit secured in the housing between 
the top wall aperture means and the end wall aperture means, whereby air 
is forced through the housing for improving the ventilation of the 
computer enclosure, when the device is mounted thereto. 
It has been found through tests that forcing air through the computer 
housing with fan of the present invention lowers operating temperatures to 
the order of 110.degree.-120.degree. F. whereby electronic components and 
the entire computer last longer and provide greater reliability. It 
further has been found through tests that blowing into the housing is far 
more effective in lowering temperatures than is exhausing air from the top 
of the housing by use of a suction fan, although the invention is not so 
limited.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT 
Turning now in greater detail to the figures of the drawings, and first to 
FIGS. 1-5, there is shown a computer or other electronic apparatus 
designated generally by the reference numeral 20. By way of specific 
example, the apparatus may be a Macintosh computer manufactured and sold 
by Apple Computer, Inc. However, it will be understood that the device of 
the invention is useful with other apparatus as well, the illustrated 
computer being by way of example to facilitate description of the 
invention. 
The computer comprises a molded plastic resin housing or enclosure 22 
having a front opening 24 framing a display screen 26. The enclosure also 
is provided at the front with a disc-receiving opening 28 of a disc drive. 
A keyboard 30 is connected to the enclosure 22 and to the computer 
components therein (not shown) by means of a flexible cable 32. 
The enclosure is provided with a flat top 34 having ventilating slots or 
apertures 36 therein. The enclosure 22 further has a rear wall 38 having a 
recessed connector 40 for receiving a mating connector of a power cord. 
Other externally accessible components include a rocker switch 42 and a 
backup battery 43 mounted above the outlet 40. 
A trough 44 (best viewed in FIG. 13) is molded in the top wall 34 of the 
enclosure and includes a bottom wall or floor 46, and a pair of side walls 
48 tapering slightly in an upward and outward direction from top to bottom 
of the trough. At an inner end of the trough there is a ventilating 
aperture 49 covered by a grill comprising vertical bars 50 to preclude 
entrance of foreign objects into the interior of the computer enclosure. A 
handle 52 overlies the inner end of the trough and has a flat top surface 
54 recessed slightly below the top wall 34 of the enclosure. The handle 
also has a reinforcing flange 56 depending from a free edge of surface 54. 
In the normal use of the computer, the fingers of one hand can be inserted 
into the trough beneath the handle 52 for lifting and carrying the 
computer. 
The open end of the trough 44 is flanked by angled or diagonal wall 
portions 58 lying on either side of the trough 44. These walls 58 are 
provided with horizontal through apertures or slots 60. Exit of air from 
the interior of the computer enclosure is afforded through the slots 60, 
the opening 49 between the bars 50, and the apertures or slots 36. Air can 
enter the housing through the opening 28, and perhaps through imperfectly 
fitted joints, but such convective cooling has often been found to be 
insufficient. 
To correct the problem of insufficient cooling, I have provided a novel 
ventilating device further details of which are shown in FIGS. 6-11 and 
which is shown in its operating environment in FIGS. 12-14. Accordingly, 
reference is invited to these remaining figures of drawing as well. The 
fan includes a housing 64, preferably of sheet metal, closed on all sides 
save for one end which is the right end in FIG. 6, which end 64 is open. 
The housing includes a first member or plate 66 which defines a top wall 
or surface 67 which is trapezoidal in outline, having side edges 68 that 
taper slightly inwardly from its rear end to its front end. In this regard 
directions such as front, rear, top, bottom and sides will be understood 
to be with reference to the above described computer, and the 
corresponding directions as to device 62 when it is mounted thereto. The 
plate 66 has a free front edge 70. The rear end of the plate 66 is bent 
down to form a rear wall 72, and then is bent forward to provide a flange 
74 substantially parallel to the top surface 67 thereof. 
The housing 64 is completed by a second, generally channel-shaped member 
106, also preferably of sheet metal. This member defines a bottom wall or 
floor 108 having a front edge 110 parallel to but extending beyond the 
first member front edge 70. The floor tapers inwardly slightly from its 
rear to its front. The rear edge of floor 108 overlies the flange 74 and 
abuts the rear wall 72. The channel-shaped member 106 further defines a 
pair of side walls 112 which diverge slightly outwardly to either side 
from the floor 108 to their upper edges 114, and which taper in height 
from a maximum at the rear end. The upper edges 114 of the side walls 
engage the underside of the top wall 66 while rear edges 116 thereof 
engage the rear wall 72. Front edges 118 of the side walls terminate short 
of the top wall 67, and are provided with diagonally-relieved upper 
corners 120 leading to horizontal edges 122 spaced from and generally 
parallel to the top wall 67 to define a recess or slot 126. The edges 122 
support rubber abutment members 124 which engage the inner and outer faces 
of the side walls 112 immediately below each edge 122, and are adhesively 
secured to these side walls. 
The flange 74 is provided with an aperture through which a screw 128 
extends and this screw is threaded into an aligned aperture in the bottom 
wall 108 of the channel-shaped member 106. Two screws 130 respectively 
extend through the side walls 117 and are threaded into apertures in 
depending flanges 88 of a bar or strap 86 which will be described later. 
The three screws 128 and 130 preferably are self-tapping screws to avoid 
the necessity of pre-tapping the holes into which they are driven. These 
screws hold the channel-shaped member 106 to the member or plate 66 to 
form the housing. 
A fan unit or blower 76 is best viewed in FIGS. 9 and 11, and comprises a 
die-cast open-ended frame 78 having a central motor housing 79 joined to 
the frame by substantially tangential integral arms 80. A flow path 82 
extends through the frame, and a rotor 84 is provided having a plurality 
of radially-extending blades 85 for impelling air through the fan unit. 
The fan unit is a commercially available unit, and preferably a Model 99XU 
made by Etri of Monroe, N.C. The blades 85 comprise an integrally molded 
plastic impeller which is clipped to the rotor and blows air axially 
through the unit. 
The fan unit 76 is a shaded-pole, axial-flow fan rated at 115 volts and 
drawing only 9 watts at 60 Hz. The fan unit therefore does not generate 
any appreciable heat. It is preferred that the fan blow air into the 
enclosure, as it has been established by tests of the above-identified 
"Macintosh" computer that this produces a much more efficient cooling 
effect than does exhausting air from the enclosure through the fan. 
However, the invention is not so limited, as results with other computers 
or apparatus may vary in this regard. 
An elongated bar or strap 86 extends beneath the top wall 67 transversely 
thereof and has depending flanges 88 at the opposite ends thereof. Screws 
or bolts 90 extend up through the front two of four mounting holes 92 
extending axially through the frame 78 of the fan unit 76. These bolts 
extend through apertures in the top plate 66 and up into the bottom ends 
of legs 94 of a U-shaped handle 96 having a bight 98 for gripping to 
permit handling of the fan, and also of the computer when the device is 
mounted thereto, as is apparent in the drawings. 
Rearwardly of the handle 96, the top wall 67 is provided with an array of 
transverse slots 100 which align with the fan unit 76 for entrance of air 
into the fan 62. At the back of the top wall 67 there is provided a switch 
102 having a rocker-type actuator 104. 
A line cord 132 extends through a fitting 134, mounted through the flange 
74 and wall 108 into the interior of the housing. The opposite or free end 
of the line cord 132 is preferably provided with a three-prong plug (not 
shown). Another electrical cord 136 extends through a similar fitting 138 
through the flange 74 and floor 108 and is provided at the opposite end 
with a electrical connector 139 selected to interconnect with the line 
cord connector 40 of the computer. The rear edge of the floor 108 is 
notched to accommodate the fittings 134 and 38, thereby allowing the 
channel-shaped member to be assembled with the top plate after the 
fittings and electrical cords have been assembled with the flange 74. 
A pair of three-conductor outlets or sockets 140 is provided on the back 
wall 72 of the fan housing. The switch 102 is wired to turn on the fan 
unit 76 and also to provide power to the line 136 as well as to the 
sockets or outlets 140. The switch 102 thereby serves as a master switch 
for both the fan and for the computer so that the computer cannot be 
turned on without also turning on the fan. 
The fan housing is tapered as described above so that it generally 
complements and fits into the tapered trough 44 at the top of the computer 
housing, the recess or slot 126 in each side wall engaging the 
corresponding parts of the handle 52, and the rubber overlays or abutment 
members 124 providing frictional gripping for resisting accidental 
withdrawal. In addition, the bottom wall 108 adjacent its front edge 110 
is provided with a dimple 142 which engages the floor 46 of the trough for 
further locking the fan in place. It will be apparent from a comparison of 
FIGS. 12-14 that the fan is inserted into the trough from the rear, with 
the projecting handle 98 thereafter serving as a handle for the computer 
as well as for the fan. The handle 98 is relatively near the front of the 
fan, and hence is relatively near the center of the computer, being 
positioned adjacent and generally over the handle 52. The rear of the 
housing 62 projects somewhat rearwardly of the computer as will be seen in 
FIGS. 4, 12 and 14. 
With the ventilating device in place, as shown in FIG. 12, the side edges 
68 of the top 67 slightly overlie the top wall of the computer enclosure 
and the fan unit 76 draws air in through the slots 100 in the top of the 
housing. The air is forced into the lower part of the housing below the 
fan unit 76 and above the floor 108 of the channel-shaped member 106. The 
air then moves to the front and exits from the open front end of the fan 
housing and through aperature 49 into the interior of the computer 
housing. Air exits from the computer housing wherever there is an opening, 
including the slots 36 and 60 at the top, the opening 28 in the front, and 
any imperfectly sealed joints. It has been found that with an ambient air 
temperature on the order of 70.degree.-75.degree. F. that the device of 
the invention will rapidly lower the operating temperature in the interior 
of the housing from approximately 170.degree. F. to between 110.degree. F. 
and 120.degree. F. Thus, the components of the computer and the entire 
computer last longer and provide greater reliability. 
While particular embodiments of the invention have been shown and 
described, it will be obvious to those skilled in the art that changes and 
modifications of the present invention, in its various aspects, may be 
made without departing from the invention in its broader aspects, some of 
which changes and modifications being matters of routine engineering or 
design, and others being apparent only after study. As such, the scope of 
the invention should not be limited by the particular embodiment and 
specific construction described herein but should be defined by the 
appended claims and equivalents thereof. Accordingly, the aim in the 
appended claims is to cover all such changes and modifications as fall 
within the true spirit and scope of the invention.