Note: Descriptions are shown in the official language in which they were submitted.
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Technical Field
The present invention relates generally to the vacuum cleaner art
and, more particularly, to a vacuum cleaner incorporating an agitator
with an internal drive motor.
Background of the Invention
A vacuum cleaner is an electro-mechanical appliance utilized to
effect the dry removal of dust, dirt and other small debris from carpets,
rugs, fabrics or other surfaces in both domestic and industrial
environments. In order to achieve the desired dirt and dust removal, a
rotary agitator is provided to beat dirt and dust from the nap of the
carpet and a pressure drop or vacuum is used to force air entrained with
this dirt and dust into the nozzle of the vacuum cleaner. The
particulate-laden air is then drawn through a bag-like filter or a cyclonic
separation chamber and filter combination which traps the dirt and dust,
while the substantially clean air is exhausted by an electrically operated
fan that is driven by an on board motor. It is this fan and motor
arrangement that generates the drop in air pressure necessary to provide
the desired cleaning action. Thus, the fan and motor arrangement is
commonly known as the vacuum or suction generator.
Many advanced, high performance vacuum cleaners incorporate
a dual motor system. In such a system, a separate agitator drive motor
is provided in addition to the motor of the suction generator. In most
designs the separate agitator drive motor is mounted on the nozzle
assembly adjacent the agitator. A gear drive or more commonly a
pulley and belt arrangement transmits the power from the agitator
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motor drive shaft to the agitator.
While very effective for its intended purpose, the mounting of a
separate agitator drive motor in front of or behind the agitator
necessitates a significant increase in the fore-aft length of the nozzle
assembly in order to accommodate the motor. This not only increases
the overall weight of the nozzle assembly but also the wheelbase and/or
the body overhang beyond the wheels. All of these characteristics
negatively impact the ease of manipulation of the vacuum cleaner in
and around furniture and, therefore, are a detriment.
In contrast, it is possible to mount the agitator drive motor above
the agitator. In this situation, no increase in the length of the nozzle
assembly and/or the wheelbase thereof is necessary to accommodate the
agitator motor. The height of the nozzle assembly must, however, be
increased significantly to provide motor clearance. This unacceptably
restricts the use of the vacuum cleaner as the resulting higher profile
will not clear many overhanging obstructions such as bed frames, tables
and chair seats. Accordingly, this is generally recognized to be an
unacceptable solution.
Another possible alternative is the mounting of the separate
agitator drive motor within the agitator itself. Such an arrangement
makes use of what would otherwise be lost space within the agitator.
Further, it allows the agitator motor to be accommodated without any
substantial increase in the height or length of the nozzle assembly.
Thus, the vacuum cleaner may be more easily manipulated on a shorter
wheel base and is of lighter overall weight. It also includes the desired
low profile which allows cleaning under bed frames, tables, chairs and
other such objects.
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Efforts have been made in the past to provide such a design. In
U.S. patent 1,953,340 to Doemling, the agitator drive motor is
positioned in the lumen of the agitator. The motor is cooled by drawing
air with the suction generator through a hollow support shaft into the
agitator lumen, then over the agitator motor and then through holes in
the agitator wall into the agitator cavity. In U.S. Patents 4,268,769 and
4,384,386 to Dorner et al., the agitator drive motor positioned in the
lumen of the agitator is cooled by using the agitator itself as a heat sink.
While providing the handling advantages noted above, the
internal agitator motor drive arrangements of the prior art fail to furnish
sufficient cooling to the agitator motor to effectively allow long term
heavy duty cycle operation. Hence, the arrangements were found to be
unsatisfactory. A need is therefore identified for an internal agitator
drive motor arrangement which provides all the handling benefits noted
above and incorporates an improved agitator motor cooling
arrangement to support long term heavy duty operation.
Brief Description of the Drawing
The accompanying drawing incorporated in and forming a part
of the specification, illustrates several aspects of the present invention
and together with the description serves to explain the principles of the
invention. In the drawing:
Figure 1 is a perspective view of the vacuum cleaner of the
present invention;
Figure 2 is a transverse sectional view of the vacuum cleaner
along lines 2-2 of Figure 4;
Figure 2a is a detailed crossectional view of the agitator and gear
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10 drive showing the engagement therebetween;
Figure 3 is a longitudinal sectional view of the vacuum cleaner;
Figure 4 is a partially sectional top view thereof; and
Figure 5 is a schematical, partially sectional plan view showing
the air path through the suction fan motor compartment.
Reference will now be made in detail to the present preferred
embodiment of the invention, an example of which is illustrated in the
accompanying drawing.
Detailed Description of the Invention
20 Reference is now made to Figure 1 showing the vacuum cleaner
of the present invention. It should be appreciated that while an
upright vacuum cleaner 10 is illustrated, canister vacuum cleaners
incorporating a driven rotary agitator in what is referred to in the art as
a "power nozzle" may also utilize and benefit from the novel internal
agitator drive motor arrangement and air cooling system of the present
invention described further below.
The overall basic design of the upright vacuum cleaner 10 is
generally well known in the art. In the typical arrangement, the upright
vacuum cleaner 10 includes a housing 14 that comprises the nozzle
30 assembly 16 and the canister assembly 18. The canister assembly 18
further includes the handle 20 and the hand grip 22. The hand grip 22
carries a control switch 24 for turning the vacuum cleaner 10 on and
off. Of course, electrical power is supplied to the vacuum cleaner 10
from a standard electrical wall outlet through a cord {not shown).
At the lower portion of the canister assembly 18, rear wheels 26
are provided to support the weight of the vacuum cleaner 10 (see also
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Figure 3). A second set of wheels 27 allow the operator to raise and
lower the nozzle assembly 16 through selective manipulation of the
height adjustment switch 28. Such a height adjustment mechanism is
well known in the art and is exemplified, for example, by the
arrangement incorporated into the Kenmore Progressive vacuum
cleaner currently available in the marketplace. To allow for convenient
storage of the vacuum cleaner 10, a foot latch 30 functions to lock the
canister assembly 18 in an upright position, as shown in Figure 1.
When the foot latch 30 is released, the canister assembly 18 may be
pivoted relative to the nozzle assembly 16 as the vacuum cleaner 10 is
manipulated to clean the floor.
The canister assembly 18 also carries an internal chamber 32
that houses a suction generator 33 (i.e. a state of the art fan and motor
combination) and a dust bag 34 for removing dirt or dust entrained in
the air stream as it passes from the nozzle assembly 16 to the suction
generator. The canister assembly 18 may also carry a final filtration
cartridge 48 to trap small particulates and prevent their reintroduction
into the environment through the exhaust air stream.
The nozzle assembly 16 includes a nozzle and agitator cavity 36
that houses a rotating agitator brush 38. The agitator brush 38 shown is
rotatably driven by a motor 40 and cooperating gear drive 42 housed
within the agitator and described in greater detail below (see Figures 2
and 3). In the illustrated vacuum cleaner 10, the scrubbing action of the
rotary agitator brush 38 and the negative air pressure created by the
suction generator 33 cooperate to brush and beat dirt and dust from the
nap of the carpet being cleaned and then draw the dirt and dust laden air
from the agitator cavity 36 to the dust bag 34. Specifically, the dirt and
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dust laden air passes serially through a suction inlet 44 and hose 46
and/or an integrally molded conduit in the nozzle assembly 16 and/or
canister assembly 18 as is known in the art. Next, it is delivered into
the dust bag 34 held in the chamber 32. The bag 34 serves to trap the
suspended dirt, dust and other particles inside while allowing the now
clean air to pass freely through the porous wall thereof and then
through the suction generator 33, final filtration cartridge 48 and
ultimately to the environment through the exhaust port 50.
Reference is now made to Figures 2 and 3 which show the
mounting of the agitator motor 40 and associated gear drive 42 in the
agitator 38 in detail. As shown, the agitator 38 is mounted for rotation
relative to the nozzle assembly 16. Specifically, a first end of the
agitator 38 includes an end cap 52 which is supported on bearings 54
on a stub shaft 55 held in mounting block 56 keyed into slot 58 in the
side of the nozzle assembly 16. An end cap 60 at the opposite end of
the agitator 38 is supported on bearings 62 mounted on the housing 64
of the motor 40. As should be appreciated, the motor 40 is fixed to the
nozzle assembly 16 by means of the mounting block 66 fixed to the
motor housing 64 and keyed in the slot 68 in the side of the nozzle
assembly.
The motor 40 drives a shaft 70 including gear teeth 72. The
drive shaft 70 extends through a bearing 74 held in the hub 76 of the
planetary gear set carrier 78. In the most preferred embodiment a fan
80 is keyed or otherwise secured to the distal end of the drive shaft 70.
The planetary gear set carrier 78 includes three stub shafts 82
that each carry a planetary gear 84. Each of the planetary gears 84
include teeth that mesh with the gear teeth 72 of the drive shaft 70.
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Additionally, the planetary gears 82 mesh with the teeth of an annular
gear 86 that is fixed to the agitator motor housing 64 by pin or other
means. Thus, it should be appreciated that as the drive shaft 70 is
driven by the motor 40, the planetary gears 84 are driven around the
annular gear 86, thereby causing the planetary gear set carrier 78 to
rotate. Planetary gear set carrier 78 also includes a drive ring 88 and
associated rubber drive boot 87 which includes a series of spaced
channels 89 that receive and engage axial ribs 91 projecting inwardly
radially from the inner wall of the agitator 38 (see also Figure 2a).
Thus, the rotation of the planetary gear set carrier 78 is transmitted by
the drive ring 88 and drive boot 87 directly to and causes like rotation
of the agitator 38. The rubber drive boot 87 provides the necessary
damping to insure the smooth transmission of power to the agitator.
Simultaneously with the rotation of the planetary gear set carrier 78 and
agitator 38, the drive shaft 70 also drives the fan 80 at a ratio of
between 4-1 to 10-1 (eg. 6-1) with respect to the agitator 38. The
resulting rapid rotation of the fan 80 helps to ensure proper cooling of
the agitator motor 40 during its operation.
More specifically, the vacuum cleaner 10 of the present
invention incorporates a novel air cooling system or circuit, which will
now be described in detail. Specifically, air is drawn into the vacuum
cleaner 10 through a vent 90 at the upper rear face of the nozzle
assembly 16 by operation of the suction generator 33 (note action arrow
A in Figures 2-4). Specifically, the air first passes through a filter 92 of
foam rubber or other appropriate material into the illumination
compartment 94 defined between the upper transparent window 96 and
the lower transparent window 98 which allow viewing of the operation
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of the agitator 38. This air then passes over and around the light source
100 so as to provide cooling thereto (note action arrows B in Figure 2).
Next, the air is drawn through the passageway 102 in the nozzle
assembly 16 and around and through an opening 104 in the end cap 52
(note action arrow C). The air then moves through the lumen of the
agitator 38 to the fan 80 driven by means of the agitator drive motor 40
(note action arrows D). The fan 80 forces the air through openings 106
in the planetary gear set carrier 78 and then around the annular gear 86
before it passes through the housing 64 of the motor 40 (note action
arrows E and F).
After passing the over the windings and other internal
components (not shown) of the agitator motor 40 for purposes of heat
exchange and cooling, the air passes through the passageway 108 into
the manifold 110 (note action arrow G). Manifold 110 includes an
outlet (not shown) in fluid communication with the agitator cavity 36.
Of course, as noted above, the agitator cavity 36 is in direct fluid
communication with a suction inlet 44 (see Figure 3) that leads through
the hose 46 (see Figure 4) into the dust bag 34 in chamber 32. From
there the air is drawn into the suction fan motor compartment 116 (see
action arrow H in Figure 5) through the filter 117 where the air passes
over the power supply board 118 to provide heat exchange cooling
thereof before passing into the housing of the suction motor 33 to
provide cooling. From there the air is exhausted through a passageway
through the final filtration cartridge 48 and ultimately to the
environment through the exhaust port 50.
From the above description, it should be appreciated that air is
ducted and directed through the vacuum cleaner 10 so as to cool in
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10 series, the light source 100, the agitator drive motor 40, the power
board 118, and the suction fan motor 33. At all points, good positive
air flow is provided by means of the negative pressure generated by the
suction generator 33. In addition, any resistance to air flow through the
lumen of the agitator 38 and around the gear drive 42 is essentially
eliminated by means of the high speed fan 80. As the air that is drawn
through the nozzle assembly 16 to cool the light source 100 and the
agitator drive motor 40 is fed back to the agitator cavity 36, there is no
drain on the performance of the suction generator 33: i.e. the same
amount of air is being pulled through the agitator cavity 36 or cleaning
area as would be if the cooling of the light source 100 and agitator
motor 40 were not taking place.
As a further advantage, since the air being supplied to cool the
light source 100 and agitator drive motor 40 comes through a vent 90
adjacent the top rear of the nozzle assembly 16, and passes through the
filter 92, only clean air is utilized. Thus, the illumination compartment
94 between the upper lower windows 96, 98 remains clean for good
visibility and easy and convenient inspection of the operation of the
agitator 38. Similarly, the lumen of the agitator 38 remains clean as do
the various openings along the air passageway. This ensures good air
flow for cooling of the agitator motor 40 over a long surface life.
The foregoing description of a preferred embodiment of the
invention has been presented for purposes of illustration and
description. It is not intended to be exhaustive or to limit the invention
to the precise form disclosed. Obvious modifications or variations are
possible in light of the above teachings. The embodiment was chosen
and described to provide the best illustration of the principles of the
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invention and its practical application to thereby enable one of ordinary
skill in the art to utilize the invention in various embodiments and with
various modifications as are suited to the particular use contemplated.
All such modifications and variations are within the scope of the
invention as determined by the appended claims when interpreted in
accordance with the breadth to which they are fairly, legally and
equitably entitled.
