U.S. patent application number 09/735815 was filed with the patent office on 2002-01-24 for air compressor assembly with shroud.
Invention is credited to Gruber, Christopher, Reger, Todd A..
Application Number | 20020009372 09/735815 |
Document ID | / |
Family ID | 24481964 |
Filed Date | 2002-01-24 |
United States Patent
Application |
20020009372 |
Kind Code |
A1 |
Gruber, Christopher ; et
al. |
January 24, 2002 |
Air compressor assembly with shroud
Abstract
An apparatus comprises a tank, an air compressor, and a motor
with an output shaft. A fan is mounted on the output shaft. A drive
assembly interconnects the motor operatively with the compressor.
The apparatus further includes a base structure and a shroud. The
base structure is configured to support the compressor, the motor
and the drive assembly on the tank. The shroud is configured to
cover the compressor, the motor, the drive assembly and the base
structure on the tank. The shroud has a cooling air inlet port and
a cooling air outlet port. A plurality of internal wall portions of
the shroud are configured to direct cooling air to flow over the
motor and the compressor upon flowing through the cover from the
inlet port to the outlet port under the influence of the fan.
Inventors: |
Gruber, Christopher;
(Cincinnati, OH) ; Reger, Todd A.; (Westchester,
OH) |
Correspondence
Address: |
Stephen D. Scanlon
Jones, Day, Reavis & Pogue
North Point
901 Lakeside Avenue
Cleveland
OH
44114
US
|
Family ID: |
24481964 |
Appl. No.: |
09/735815 |
Filed: |
December 13, 2000 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09735815 |
Dec 13, 2000 |
|
|
|
09619447 |
Jul 19, 2000 |
|
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Current U.S.
Class: |
417/234 ;
417/201 |
Current CPC
Class: |
F02B 63/06 20130101;
F02B 63/02 20130101; F04B 35/06 20130101; F02B 75/06 20130101; F04B
39/0094 20130101 |
Class at
Publication: |
417/234 ;
417/201 |
International
Class: |
F04B 053/00; F04B
023/14 |
Claims
1. An apparatus comprising: a tank configured to contain air at an
elevated pressure; an air compressor operative to supply compressed
air for storage in said tank; a motor with an output shaft; a fan
mounted on said output shaft; a drive assembly configured to
interconnect said motor operatively with said compressor; a base
structure configured to support said compressor, said motor and
said drive assembly on said tank; and a shroud configured to cover
said compressor, said motor, said drive assembly and said base
structure on said tank; said shroud having a cooling air inlet
port, a cooling air outlet port, and a plurality of internal wall
portions configured to direct cooling air to flow over said motor
and said compressor upon flowing through said cover from said inlet
port to said outlet port under the influence of said fan.
2. An apparatus as defined in claim 1 wherein said output shaft has
a first axis, said compressor contains a piston supported for
reciprocation along a second axis perpendicular to said first axis,
and said internal wall portions of said shroud are configured to
define an L-shaped flow path extending along said first and second
axes.
3. An apparatus as defined in claim 2 wherein said inlet and outlet
ports are located at opposite ends of said L-shaped flow path.
4. An apparatus as defined in claim 1 wherein said shroud has a
lower section configured as a skirt extending around the periphery
of said base structure, and further has an upper section configured
as a cover which extends over said compressor, said motor and said
drive assembly when said upper section is received over said lower
section in an installed position.
5. An apparatus as defined in claim 4 wherein said lower section of
said shroud is fixed to said base structure by a plurality of
fasteners that are spaced apart about said periphery of said base
structure, and said upper section of said shroud is configured to
be fastened to said lower section by a solitary fastener accessible
from above said upper section.
6. An apparatus as defined in claim 1 wherein said shroud has a
recess configured as a tool storage compartment.
7. An apparatus as defined in claim 1 wherein said shroud has a
plurality of bores, each of which is configured to receive a
corresponding quick connect fitting in a manually releaseable
interference fit.
8. An apparatus as defined in claim 1 wherein said shroud is
configured to enclose air pressure gages and has access openings
for the faces of the air pressure gages.
9. An apparatus as defined in claim 1 wherein said shroud is
configured to enclose an on-off switch for said motor and has an
access opening configured for a key to operate said on-off
switch.
10. An apparatus as defined in claim 1 wherein said shroud has an
access opening for an air pressure control knob.
11. An apparatus as defined in claim 1 wherein said shroud has an
access opening for an air pressure relief valve stem.
Description
[0001] This application is a continuation-in-part U.S. patent
application Ser. No. 09/619,447, filed Jul. 19, 2000, entitled "Air
Compressor Assembly with Dual Cooling Fans."
FIELD OF THE INVENTION
[0002] The present invention relates to an air compressor, and
particularly relates to an air compressor that is mounted on a
tank.
BACKGROUND OF THE INVENTION
[0003] An air compressor may be used to provide a hand-held tool
with pneumatic power. The compressor is part of an apparatus that
further includes a motor for driving the compressor and a tank for
storing compressed air. A drive assembly operatively interconnects
the motor with the compressor, and is mounted on the tank with the
motor and the compressor. The drive assembly may include a pulley,
a flywheel, and a linkage structure that cooperate to reciprocate a
piston within the compressor upon rotation of an output shaft at
the motor. The reciprocating piston pumps compressed air into the
tank. A pneumatic power hose extends from the tank to the
pneumatically powered tool. In some cases the tank is provided with
wheels and a handle so that the entire apparatus is portable.
SUMMARY OF THE INVENTION
[0004] In accordance with the present invention, an apparatus
comprises a tank, an air compressor, and a motor with an output
shaft. A fan is mounted on the output shaft. A drive assembly
interconnects the motor operatively with the compressor. The
apparatus further includes a base structure and a shroud. The base
structure is configured to support the compressor, the motor and
the drive assembly on the tank. The shroud is configured to cover
the compressor, the motor, the drive assembly and the base
structure on the tank.
[0005] The shroud has a cooling air inlet port and a cooling air
outlet port. A plurality of internal wall portions of the shroud
configured to direct cooling air to flow over the motor and the
compressor upon flowing through the cover from the inlet port to
the outlet port under the influence of the fan.
[0006] In a preferred embodiment of the invention, the output shaft
has a first axis, and the compressor contains a piston supported
for reciprocation along a second axis perpendicular to the first
axis. The internal wall portions of the shroud are configured to
define an L-shaped flow path extending between the inlet and outlet
ports along the first and second axes.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is an isometric view of an apparatus comprising a
preferred embodiment of the present invention;
[0008] FIG. 2 is a partial top view of the apparatus of FIG. 1,
with certain parts omitted for clarity of illustration;
[0009] FIG. 3 is an enlarged sectional view, taken from above,
including parts shown in FIG. 2;
[0010] FIG. 4 is a side view of a part shown in FIG. 3;
[0011] FIG. 5 is a schematic side view of another part shown in
FIG. 2;
[0012] FIG. 6 is an enlarged sectional view of parts of the
apparatus of FIG. 2;
[0013] FIG. 7 is a view taken on line 7-7 of FIG. 6;
[0014] FIG. 8 is an enlarged sectional view of parts shown in FIGS.
1 and 2;
[0015] FIG. 9 is a partial view, taken from above, of parts shown
in FIGS. 1 and 2;
[0016] FIG. 10 is a top view of a part shown in FIGS. 1 and 9;
and
[0017] FIG. 11 is an enlarged view showing a portion of the part of
FIG. 10 in relation to a connector tool used with the apparatus of
FIG. 1.
DESCRIPTION OF A PREFERRED EMBODIMENT
[0018] An apparatus 10 comprising a preferred embodiment of the
present invention is shown in FIG. 1. The apparatus 10 includes a
tank 12 with a stand 14, a pair of wheels 16, and a handle bar 18.
The tank 12 defines a storage chamber 19 containing air at an
elevated pressure. A compressor assembly 20 is mounted on the tank
12. The compressor assembly 20 is constructed in accordance with
the invention, and operates to supply the storage chamber 19 with
compressed air. An outlet hose 21 extends from the compressor
assembly 20 to a pneumatically powered tool (not shown) such a
hand-held nail gun, impact wrench, or the like.
[0019] As shown in FIG. 1, the compressor assembly 20 includes a
shroud 22 with upper and lower sections 24 and 26. The shroud 22
covers the parts of the compressor assembly 20 that are shown in
FIG. 2. These include a motor 28 and a compressor 30. A flywheel 32
is included as part of a drive assembly between the motor 28 and
the compressor 30. When the compressor 30 is driven by the motor
28, a pneumatic supply line 34 conveys compressed air from an
outlet port 36 on the compressor 30 to an inlet port 38 on the tank
12.
[0020] A base structure 40 supports the motor 28 and the compressor
30 on the tank 12. The base structure 40 in the preferred
embodiment of the invention is a one-piece metal part defining a
flat, rectangular platform 42 with a pair of legs 44. The legs 44
are edge portions of the base structure 40 and project downward
from the platform 42 to the cylindrical side wall 46 of the tank. A
lower section 48 of each leg 44 extends radially into abutment with
the side wall 46 and is welded to the side wall 46.
[0021] The motor 28 has an output shaft 50 with a longitudinal
central axis 51. A first end portion 52 of the output shaft 50
projects a short distance from the motor 28 at one side of the
compressor assembly 20. A first cooling fan 54 is mounted on the
first end portion 52 of the output shaft 50. A second end portion
56 of the output shaft 50 projects oppositely from the motor 28 and
is substantially longer than the first end portion 52. A second
cooling fan 58 is mounted on the second end portion 56 of the
output shaft 50. Also mounted on the second end portion 56 is a
pulley 60 for a drive belt 62 that transmits torque from the output
shaft 50 to the flywheel 32.
[0022] The compressor 30 has distinct parts defining a housing 64
and a bracket 66. The housing 64 a generally rectangular block-like
structure, and is mounted on a rectangular end portion 68 of the
bracket 66 by fasteners 70 at the four comers of the housing 64.
The flywheel 32 is mounted on a shaft 72 at an opposite end portion
74 of the bracket 66. A pair of bearings 76 and 78 (FIG. 3) are
contained within that end portion 74 of the bracket 66. The
bearings 76 and 78 support the shaft 72 and the flywheel 32 for
rotation about an axis 79 parallel to the axis 51 of the output
shaft 50 (FIG. 2).
[0023] A lower portion 80 of the compressor housing 64 defines an
internal cylinder containing a piston 82. The piston 82 is
supported for reciprocating movement along an axis 83 perpendicular
to the axes 51 and 79. An upper portion 84 of the compressor
housing 66 includes an air intake structure 86. Inlet and outlet
valves (not shown) are located within the upper portion 84 of the
housing 64. The valves operate to direct air through the housing 64
from the intake structure 86 to the outlet port 36 under the
influence of the piston 82.
[0024] The piston 82 in the illustrated embodiment is part of a
linkage member 90 that is connected to the flywheel 32. A bearing
92 (FIG. 3) supports the linkage member 90 on a support member 94
that projects from the flywheel 32. The support member 94 in the
preferred embodiment is a flat head screw. When the flywheel 32
rotates about the axis 79, the screw 94 moves along a circular path
extending around the axis 79. This causes the linkage member 90
also to move around the axis 79, and simultaneously to move back
and forth along the axis 83. The piston 82 then reciprocates along
the axis 83, and thus pumps compressed air to the outlet port 36,
upon rotation of the flywheel 32 under the influence of the output
shaft 50 at the motor 28. A piston cap 95 and a fastener 96
together support a piston ring 98 on the piston 82.
[0025] More specific features of the compressor assembly 20 are
shown in FIGS. 3-14. For example, as shown in FIG. 3, the flywheel
32 has an inner surface 100 defining a bore 101 in which the shaft
72 is received. The inner surface 100 is conical and is tapered
uniformly along its length such that the inner end 102 of the bore
101 has a diameter that is slightly less than the diameter at the
outer end 104. The shaft 72 is equally tapered at its outer surface
106, and is received within the bore 101 in an interference fit
with the flywheel 32. The outer surface 106 of the shaft 72 is
engaged in an interference fit with the inner race 108 at the first
bearing 76 in the same manner. A reduced-diameter section 110 of
the shaft 72 has a cylindrical outer surface 112 which is likewise
engaged in an interference fit with the inner race 114 at the
second bearing 78.
[0026] The shaft 72 is machined such that the outer surface 106
complies with close dimensional tolerances. However, the inner
surface 100 of the flywheel 32 is not machined to close dimensional
tolerances, but instead has the original configuration attained
upon formation of the flywheel 32 as a cast metal part. The taper
of the adjoining surfaces 100 and 106 enables the interference fit
to be established without the need for precision machining at the
inner surface 100. The manufacturing process is simplified, and a
corresponding cost savings is achieved, by forming the
torque-transmitting connection between the flywheel 32 and the
shaft 72 in this manner.
[0027] The linkage member 90, which may also be referred to as a
piston, is an elongated part with a longitudinal central axis 121
(FIGS. 3-4). An end portion 122 of the linkage member 90 is
configured as a circular disk with a diameter generally
perpendicular to the axis 121. That end portion 122 defines the
piston 82 (FIG. 2), as noted above.
[0028] The bearing 92 at the other end of the linkage member 90 is
mounted on the linkage member 90 in an interference fit.
Specifically, the elongated body 124 of the linkage member 90 has a
pair of openings 129 and 131 which are spaced-apart along its
length. The first opening 129 comprises a pocket for the bearing
92, and is defined by an inner edge surface 134. The inner edge
surface 134 extends continuously in a closed loop around an axis
135 which intersects the axis 121 orthogonally. A major section 136
of the inner edge surface 134 has an annular contour centered on
the axis 135, and thus defines a circular portion 137 of the
opening 129. A minor section 138 of the inner edge surface 134 has
a U-shaped contour extending radially outward from a gap 139 in the
major section 136, and thus defines a slot-shaped portion 141 of
the opening 129. The peripheral edge surface 142 of the body 124
has a similar contour at a terminal end portion 144 of the body 124
that projects radially outward with the slot 141. The terminal end
portion 144 of the body 124 is thus configured as a living hinge
with a pivotal axis 145 parallel to the axis 135. The gap 139 can
enlarge slightly upon flexure of the hinge 144 so that the bearing
92 can be installed in the circular portion 137 of the opening 129
with an interference fit between the cylindrical outer surface 146
of the bearing 92 and the annular inner surface 136 at the opening
129.
[0029] In accordance with a particular feature of the invention,
the linkage member 90 is a cast metal part. When the linkage member
90 is being formed in a mold cavity, the configuration of the hinge
portion 144 provides a path for the molten metal to flow
circumferentially around the gap 139 at the annular section 136 of
the inner edge surface 138. This enables the surface 138 to be
formed precisely to specified tolerances because the molten metal
can flow around the entire surface 138 without encountering any
dead ends in the mold cavity. As a result, the annular section 136
of the surface 138 in the preferred embodiment is not machine, but
instead has the original condition attained upon formation in the
mold cavity. The time and expense of machining the surface 138 is
thus avoided by the invention.
[0030] The output shaft 50 (FIG. 2) extends through the bracket 66
and the linkage member 90 as it projects axially from the motor 28
to the location of the second cooling fan 58. As shown
schematically in FIG. 5, an opening 149 at the side of the bracket
66 provides clearance for the output shaft 50 to extend through the
bracket 66. The second opening 131 (FIG. 4) in the body 124 of the
linkage member 90 provides clearance for the output shaft 50 to
extend through the linkage member 90. This enables the motor 28,
the compressor housing 64 and the bracket 66 to be installed over
the platform 42 in an arrangement that is more compact than it
would be if the output shaft 50 were located beside rather than
within the bracket 66 and the linkage member 90. Preferably, as
shown in FIG. 4, an inner edge surface 150 of the body 124 provides
the opening 131 with an ovate periphery that closely surrounds the
ovate path of movement 151 taken by the shaft 50 relative to the
linkage member 90 upon oscillation of the linkage member 90 under
the influence of the rotating flywheel 32. This helps to minimize
the size of the linkage member 90 by minimizing the size of the
opening 131.
[0031] A slot 161 (FIG. 2) in the base platform 42 also helps the
compressor assembly 20 to be more compact. The slot 161 provides
clearance for the flywheel 32 to project radially through the
platform 42. The height of the flywheel 34 above the platform 42 is
reduced accordingly.
[0032] An elastomeric pad 170 is adhered to the platform 42
directly beneath the motor 28. A clamping strap 172 extends over
the motor 28, and is fastened to the platform 42 at its opposite
ends so as to clamp the motor 28 firmly against the pad 170. In
this arrangement, the pad 170 effectively isolates the platform 42
and the tank 12 from the vibration of the motor 28.
[0033] The compressor 30 also vibrates. However, a vibration
damping structure 180 (FIGS. 6-7) is interposed between the bracket
66 and the platform 42 so as to isolate the base structure 40 and
the tank 12 from the vibrations of the compressor 30. As shown in
FIG. 2, an inner edge surface 182 of the platform 42 defines an
opening 183 beneath the end portion 74 of the bracket 66 beside the
flywheel 32. As shown in FIGS. 6-7, a cylindrical mounting boss 190
projects downward from the bracket 66 and extends through the
opening 183. The damping structure 180 engages and supports the
boss 190 within the opening 183.
[0034] More specifically, the mounting boss 190 and the bracket 66
are portions of a one-piece cast metal structure. By "one-piece" it
is meant that the structure a single unit of homogeneous material
and is free of separate but joined elements. The opening 183 in the
platform 42 is keyhole-shaped with a major portion 193 and a minor
portion 195. The damping structure 180 is a one-piece elastomeric
part configured as a ring or grommet having a tubular central
portion 200 and a pair of circular flanges 202 and 204 projecting
radially from its opposite ends. The flanges 202 and 204 are
preferably alike. Each flange 202 and 204 has a diameter that is
less than the diameter of the major portion 193 of the opening 183
but greater than the diameter of the minor portion 195.
Accordingly, when the ring 180 is received over the boss 190, the
bracket 66 can be mounted on the platform 42 by moving the ring 180
and boss 190 longitudinally through the major portion 193 of the
opening 183, and by subsequently moving them transversely to an
installed position within the minor portion 195 of the opening 183.
The adjacent edge portion 206 of the platform 42 is then received
closely between the flanges 202 and 204 on the ring 180. The first
flange 202 is firmly engaged axially between the bracket 66 and the
platform 42. The second flange 204 is firmly engaged axially
between the platform 42 and a flange 210 at the lower end of the
boss 190. The ring 180 is thus engaged firmly between the bracket
66 and the platform 42 so as to isolate the base structure 40 from
vibration that could otherwise be transmitted through the bracket
66 from the compressor housing 64 and/or the rotating flywheel 32
to the platform 42.
[0035] Preferably, the mounting boss 190 projects from the end
portion 74 of the bracket 66 in an orientation in which the
longitudinal central axis 215 of the mounting boss 190 intersects
the flywheel axis 79 orthogonally, as shown schematically in FIG.
5. This helps to stabilize the rotating flywheel 32 relative to the
platform 42. As further shown schematically in FIG. 5, an axially
extending slot 217 reduces the thickness of the mounting boss 190.
This promotes a consistent flow of molten metal material upon
formation of the boss 190 in a mold cavity with the bracket 66.
[0036] As noted above with reference to FIG. 1, the shroud 22
covers the parts of the compressor assembly 20 that are mounted on
the platform 42. The lower section 26 of the shroud 22 is
configured as a skirt that extends fully around the periphery of
the compressor assembly 20. Fasteners 220 mount the lower section
26 on the base structure 40 adjacent to the four comers of the base
structure 40. The handle bar 18 also is fastened to the base
structure 40, as shown in FIG. 8. The upper section 24 of the
shroud 22 is a removable cover that extends fully over the other
parts of the compressor assembly 20. Four adjacent rim portions 222
of the lower section 26, one of which is shown in FIG. 8, engage
corresponding rim portions 224 of the upper section 24 to locate
the upper section 24 in its installed position. A solitary fastener
226 (FIG. 9) at the rear of the shroud 22 releasably secures the
upper section 24 directly to the lower section 26. As compared with
the fasteners 220 that secure the lower section 26 to the base
structure 40, that fastener 226 is easily accessible from above the
shroud 22. The upper and lower sections 24 and 26 of the shroud 22
may further be configured to snap together into interlocked
engagement.
[0037] The upper section 24 of the shroud 22 has an inlet grille
230 for receiving cooling air, and has an outlet grille 232 for
exhausting cooling air. When the upper section 24 of the shroud 22
is installed over the lower section 26, as shown in FIG. 9, a
plurality of internal wall portions of the upper section 24 direct
cooling air to flow over the motor 28 and the compressor 30 upon
flowing through the shroud 22 along a generally L-shaped flow path
extending from the inlet grille 230 to the outlet grille 232. A
mock grille 234 (FIG. 10) is located opposite the inlet grille 230
for symmetry of appearance.
[0038] The internal walls include a pair of parallel walls 240 and
242 on opposite sides of the motor 28. These walls extend
vertically from the top of the upper section 24 nearly to the level
of the base platform 42, and extend horizontally from the inlet
grille 230 to the opposite end of the motor 28. Another internal
wall 244 projects at an angle from the end of the wall 242. That
wall 244 extends vertically downward from the top of the upper
section 24 above the linkage member 90, the flywheel 32 and the
adjacent end portion 74 of the bracket 66. An arcuate internal wall
246 projects from the opposite side of upper section 24. The
arcuate wall 246 also extends from the top of the upper section 24
nearly to the base platform 42. Additionally, the first and second
cooling fans 54 and 58 are both oriented to move air in the same
direction extending from right to left along the axis 51, as viewed
from above in FIG. 9, and thereby to drive the flow of air along
the L-shaped flow path.
[0039] Other features of the upper section 24 are shown in the top
view of FIG. 10. These include a pair of recesses 250 and 252 for
holding tools. Cylindrical bores 254 in each recess 250 and 252 are
configured to hold quick-connect fittings of various sizes. For
example, as shown in FIG. 11, a bore 254 is defined by a
cylindrical inner surface 256. The cylindrical inner surface 256 is
slightly tapered radially inward. The cylindrical inner surface 256
is thus configured with reference to a corresponding-size fitting
258 so as to engage a cylindrical outer surface 260 of the fitting
258 in a manually releaseable interference fit. The sizes of the
other 254 are likewise specified to correspond to the sizes of
fittings that are used with the various pneumatically operated
tools that can be powered by the apparatus 10.
[0040] As best shown in FIG. 1, the bores 254 in the upper recess
250 are arranged in a row along a shoulder structure 262 at a rear
inner corner of the recess 250. This provides clearance for other
tools to be stored at the top of the shroud 22.
[0041] A recessed forward region 264 of the upper section 24 also
has a plurality of openings. These include an access opening 266
(FIG. 10) for an air pressure control knob 268 (FIG. 1), and a pair
of access openings 270 for the faces of pressure gages 272 that are
otherwise enclosed within the shroud 22. A smaller access opening
274 is configured for a key to reach an on-off switch (not shown)
within the shroud 22. Another smaller access opening 276 is
configured for a pressure relief valve stem 278 to project upward
from the shroud 22. Those parts of the compressor assembly 20 can
be operatively interconnected with the motor 28, the tank inlet 38,
and the tank outlet 278 (FIG. 2) within the shroud 22 by the use of
any suitable control system structure known in the art.
[0042] The invention has been described with reference to a
preferred embodiment. Those skilled in the art will consider
improvements, changes and modifications in view of the foregoing
description. Such improvements, changes and modifications are
intended to be within the scope of the claims.
* * * * *