Note: Descriptions are shown in the official language in which they were submitted.
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VACUUM CLEA1~TER.
~IVITFi REVERSIBLE ROTARY .AGITATOR
This application claims the benefit of U.S. Provisional Patent
Applic anon S erial 1Vo . 601362,960 file d March 8, 20 02.
Technical Field
The present invention relates generally to the vacuum cleaner field,
and, more particularly, to a vacuum cleaner having a reversible rotary
agitator for propelling or drawing a nozzle assembly of the vacuum cleaner
in a forward or rearward direction.
Background of the Invention
Upright vacuum cleaners and power head assemblies for canister
vacuum cleaners in all of their designs and permutations have become
increasingly popular over th a years. Uprigh t vacuum cleaners ge nerally
incorporate a nozzle assembly which rides on wheels over a floor surface
to be cleaned and a canister assembly that is pivotally connected to tlae
nozzle assembly. The canister assembly typicall;y~ includes an operating
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handle that is manipulated by an operator to move the vacuum cleaner to
and fro across the floor. The canister assembly also includes a dirt
collection vessel comprising either a bag-like filter or a dirt cup that may
include a cyclonic separation chamber and filter combination. The dirt
collection vessel traps dirt and debris while substantially clean air is
exhausted by an electrically operated fan that is driven by an onboard
motor. It is this fan and motor arrangement that generates the drop in air
pressure necessary to provide the desired cleaning action.
In most upright vacuum cleaners sold today, a rotary agitator is also
provided in the nozzle assembly. The rotary agitator includes tufts of
bristles, brushes, beater bars or the like to beat dirt and debris from the
nap
of a carpet being cleaned while the pressure drop or vacuum is used to
force air entrained with this dirt and debris into a. nozzle housing of the
vacuum cleaner. Power head assemblies for canister vacuum cleaners
simi larly in clud a a ro tary ag itato r in th a no zzle asse mbly.
In either the upright vacuum cleaner or the power head assembly, as
the agitator rotates and engages the surface being cleaned, the agitator has
a tendency to pull the nozzle assembly forward in accordance with its
direction of rotation. The present invention utilizes the motion imparted to
the nozzle assembly of the vacuum cleaner by a reversibly driven agitator
to full advantage and to provide a vacuum cleaner that is self propelled in
both a forward and rearward direction. Such a vacuum cleaner works with
the operator at all times and is easier to move to and fro across the surface
being c leaned.
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Summarx of the Invention
In accordance with the purposes of the present invention as
described herein, an improved self propelled vacuum cleaner is provided.
The vacuum cleaner includes a cannister assembly, a suction generator, and
a nozzle assembly. The nozzle assembly includes a housing that defines an
agitator cavity, an agitator mounted in the agitator cavity for rotation in a
forward and rearward direction for propelling the nozzle assembly, and a
drive motor for driving the agitator. An actuator for controlling operation
of the drive motor and rotation direction of the a3;itator may be carried on
either the cannister assembly or the nozzle assembly.
In one embodiment, for example, a moveable hand grip is slidably
mounted to a control handle for directing the forward and rearward rotation
of the agitator and direction of movement of the nozzle assembly. As force
is exerted on the hand grip by an operator, the hand grip slides along a stem
of the control handle. A forward thrust moves the hand grip forward
forcing the closure of a forward switch and the application of a voltage
signal to a controller. Similarly, a reverse thrust exerted on the hand grip
moves the hand grip rearward opening the forward switch and forcing the
closure of a rearward switch and the application of a voltage signal to the
controller. The status of the sw itches is monitored by the controller.
In accordance with another aspect of the present invention, the
controller is programmed to drive the drive motoa~ in either of the first
direction and the second direction upon receipt of a signal from the
actuator. More specifically, the controller may be programmed upon a
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change of state of the actuator signal to remove power from the drive
motor and to reapply power to the drive motor such that the agitator is
rotated in a different direction. In one embodiment, the reapplication of
power to the drive motor is delayed by the controller for between 0.1
second and 1.0 second to allow the agitator rotating in the first direction to
slow significantly, if not stop, before power is reapplied to drive the
agitator in the second direction and vice versa. In addition, the power
reapplied to the agitator drive motor may be incrementally increased using
a ramp or step function, or the like, to a normal operating level in order to
reduce arcing and inrush current peaks.
In accordance with the broadest teachings of the present invention,
the vacuum cleaner described generally above many be an upright vacuum
cleaner or extractor, or a canister type vacuum cleaner equipped with a
power nozzle as are well known in the art. In either instance, the agitator
1 S drive moto r may be pos itxoned coaxially with the ag itator including
within
the agitator. Alternately, the nozzle assembly ma;y include a belt and pulley
assembly or even a gear drive connecting a remotely positioned drive
motor to the agitator as is also well known in the art. In addition, the
canister assembly in either instance, includes a collection vessel
comprising either a bag-like filter or a dirt cup that may but does not
necessarily have to include a cyclonic separation chamber and filter
combination. The collection vessel traps dirt and debris while substantially
clean air is exhausted by an electrically operated fan that is driven by an
onboard mo tor.
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In accordance with another aspect of the 1>resent invention, a
method of propelling a nozzle assembly of a vacuum cleaner having a
power driven agitator in a forward or rearward dnrection may be broadly
defined as including the step of selectively rotating the agitator in a first
5 direction to draw the nozzle assembly forward and in a second direction to
draw the nozzle assembly rearward. The method may be alternatively
described as including the steps of sensing operator input to determine a
direction of desired nozzle assembly movement and driving the agitator to
draw the nozzle assembly in the desired direction.
In accordance with still another aspect of the present inventions a
vacuum cleaner includes a nozzle assembly including an agitator cavity and
at least one rotary agitator mounted for rotation in the agitator cavity. That
rotary agitator is rotated in a first direction for drawing fhe nozzle
assembly
forward and in a second direction for drawing the nozzle assembly
rearward. The vacuum cleaner also includes a cannister assembly
connected to the nozzle assembly, a suction generator, a drive motor for
driving the at least one agitator, and a.n actuator for controlling operation
of
the drive motor and ro tation direction of the at least one agitator. In
accordance with the broad teaching of the present invention, the suction
generator, the at least one agitator, and the drive motor may each be carried
on one of the nozzle assembly and cannister assembly.
In the following description there is shown and described one
possible embodiment of this invention, simply by way of illustration of one
of the modes best suited to carry out the invention. As it will be realized,
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the invention is capable of other different embodiments, and its several
details are capable of modification in various, obvious aspects all without
departing from the invention. Accordingly, the drawings and descriptions
will be regarded as illustrative in nature and not as restrictive.
Brief Description of the Drawins
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 a vacuum cleaner constructed in
accordance with the teachings of the present invention;
Figure 2 is a schematic block diagram showing the control circuit
which controls the application of electrical power to the agitator motor and
thus the direction the nozzle assembly is propelled;
Figure 3 is a cross-sectional view through the nozzle assembly of
the vacuum cleaner showing the agitator and agitator drive arrangement;
and
Figure 3a is a detailed cross-sectional view through the agitator.
Reference will now be made in detail to the present invention, an
example of which is illustrated in the accompanying drawing.
Detailed Description of the Invention
Reference is now made to Figure 1 showing a preferred embodiment
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of an upright vacuum cleaner 10 of the present invention. It should be
appreciated that while an upright vacuum cleaner' 10 is illustrated,
embodiments of the present invention also include different upright
vacuum cleaners and canister vacuum cleaners eduipped with a powerhead
incorporating a power driven agitator such as shown, for example, in U.S.
Patent 6,148,474 which is owned by the assignee of the present invention
and is incorporated herein by reference.
The uprzght vacuum cleaner 10 includes a nozzle assembly 16 and a
canister assembly 18 pivotally connected to the nozzle assembly. The
canister assembly 18 further includes a control handle 20 and a hand grip
22. A power switch 24 is provided for turning the vacuum cleaner on and
off. Of course, electrical power is supplied to the vacuum cleaner 10 from
a standard a lectrical wall o utlet through a cord (no t shown) a s is know n
in
the art.
In the present preferred embodiment, the hand grip 22 is slidably
mounted to a stem 21 of the control handle 20. As forces are exerted on
the hand grip 22 by an operator, the hand grip 22 slides along the stem 21
as shown by action arrows A in Figure 1. A forward thrust moves the hand
grip 22 forward toward the cannister assembly 18 forcing closure of a
forward switch 23 and the application of a voltage signal (Vcc) generated
by a power supply (not shown) to a first pin of controller 27. Similarly, a
reverse thrust exerted on the hand grip 22 moves t:he hand grip rearward
away from the cannister assembly 18 opening the forward switch and
forcing closure of a rearward switch 25 and the application of the voltage
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signal (Vcc) to a second pin of controller 27. Dependent upon the desired
direction of movement of the nozzle assembly 15 as indicated by the
open/closed states of the forward and rearward switches 23 and 25, the
voltage signal (Vcc) generated by a power supply (not shown) is selectively
applied to the first or second pins of controller 27.
As shown in Figure 2, the con~oller 27 in turn generates an output
signal (S1) which is applied to and directs the operation of relay29 and
agitator motor 40. In the present preferred embadiment, the electrical
power is converted from AC to DC by converter 31. The DC power is
applied to the agitator motor 40 through relay 29 such that the motor is
rotated in a first direction for drawing the nozzle assembly 16 forward or in
a second direction for drawing the nozzle assembly rearward depending
upon the open/closed states of the switches 23 am.d 25.
Preferably, the controller is programmed to monitor the open/closed
states of the switches 23 and 25 and to generate the output signal (S1 )
which operates relay 29 accordingly. The controller 27 is further
programmed to remove the DC power provided through relay 29 to the
drive motor 40 and to reapply power to the drive motor such that the
agitator is rotated in a different direction upon a change in state of the
switches 23 and 25. In other words, when the operator of the vacuum
cleaner 10 desires to change the direction of movE;ment of the vacuum
cleaner 10 by actuating the. hand grip 22, the controller 27 generates a
different output signal (S1) causing the removal and reapplication of DC
power to the agitator motor 40 through relay 29.
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In one preferred embodiment, the reapplication of power to the
drive motor 40 is delayed by the controller 27 for between 0.1 second and
1.0 second to allow the agitator 38 rotating in the first direction to slow
significantly, if not stop, before DC power is reapplied to drive the agitator
3 8 in the second direction and vice versa. It should be noted that the DC
power reapplied to the agitator drive motor 40 may be incrementally
increased using a ramp or step function, or the l~:e, to a normal operating
level in order to reduce arcing and inrush current peaks.
A pair of rear wheels 26 (partially shown) are provided at a lower
portion of the cannister assembly 18 and a pair of front wheels 27 are
provided on the nozzle assembly 16. Together, these wheels 26, 27 support
the vacuum cleaner 10 for movement across the floor. T'o allow for
convenient stowage of the vacuum cleaner 10, a foot latch (not shown) may
function to lock the canister assembly 18 in an upright position as shown in
Figure 1. When the foot latch is released, the canister assembly 18 may be
pivoted relative to the nozzle assembly 16 as the vacuum cleaner 10 is
manipulated to-and-fro to clean the floor.
In the present preferred embodiment, the canister assembly 18
includes a cavity adapted to receive and hold a collection assembly or
vessel 12. A detailed description of the dust collection vessel 12 of the
present preferred embodiment may be found in PCT Application
PCT/USO1/47401, entitled Cyclonic Vacuum Cleaner with Filter and Filter
Sweeper, filed November 13, 2001. Although described as accessible from
the front of the vacuum cleaner 10 in the noted PCT application, the dust
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collection vessel 12 may likewise be accessible from the rear of the
vacuum cleaner 10. In accordance with the broad teaching of the present
invention, the dust collection vessel may alternatively include a bag-like
filter to receive dirt and debris as is also well known in the art.
5 The canister assembly 18 further carries a suction generator or fan
33 and suction fan drive motor 34. Together, the suction fan 33 and its
cooperating drive motor 34 function to generate a vacuum airstream for
drawing air, dust, dirt and debris from a surface to be cleaned through the
nozzle assembly 16 to the collection vessel 12. While the suction fan 33
10 and suction fan drive motor 34 are illustrated as being carried on the
canister assembly 18, it should be appreciated that one or bath could
likewise be carried on the nozzle assembly 16 if desired.
The nozzle assembly 16 includes a nozzle housing 35 that defines an
agitator cavity 36 that receives a rotating agitator 38. The agitator 38
shown is rotatably mounted in the agitator cavity 36 and driven by a motor
40 and cooperating gear drive 42. In the present preferred embodiment, the
motor 40 and gear drive 42 are coaxial with and housed within the agitator
38 as is described in greater detail below (see Figures 3 and 3a). While ii~e
vacuum cleaner of the present preferred embodiment is described with the
agitator motor40 positioned coaxially with and held within the agitator 38,
the motor could be positioned outside of the agitator in either tha nozzle
assembly 16 or the canister assembly 18 utilizing a drive arrangement
incorporating a belt and pulley assembly and/or a gear drive assembly in
any manner desired.
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In the illustrated vacuum cleaner 10, the scrubbing action of the
rotary agitator 38 and the negative air pressure created by the suction fan
33 and drive motor 34 cooperate to brush and beat dirt and dust from the
nap of the carpet being cleaned and then to draw the dirt and dust laden air
from the agitator cavity 36 to the dust collection vessel 12. Specifically,
the dirt and dust laden air passes serially through a suction inlet defined by
the nozzle housing 35 and hose andlor an integrally molded conduit in the
nozzle housing 35 andlor canister assembly 18 as is generally known in the
art. Next, the dirt and dust laden air is delivered into the dust collection
vessel 12 which serves to trap the suspended dirt, dust and other particles
inside while allowing the now clean air to pass freely through to the
suction fan 33 and ultimately to the environment through an exhaust port
50.
Reference is now made to Figures 3 and 3a which show the
mounting of the agitator motor 40 and associated ;gear drive 42 coaxially
with and w ithin the agitato r 3 8 in detail. A s 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 SS held in mounting block 56 keyed into slot 58
in the side of ~e nozzle housing 35. An end cap 60 at the opposite end of
the agitator 38 is supported on hearings 62 mounted on the housing 64 of
the motor 40. As should be appreciated, the motor 40 is fixed to the nozzle
housing 35 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 housing.
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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 bo the distal end of the drive shaft 70.
' The planetary gear set carrier 78 includes three stub shafts 82 that
each carry a p lanetary gear 84 . Each of th a planetary gears 84 includ a
teeth
that mesh with the gear teeth 72 of the drive shaft 70. 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.
As best shown in Figure 3a, 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. Thus,
the rotation of the planetary geax set carrier 78 is transmitted by the drive
ring 88 and drive boot 87 directly to and causes l~C:e rotation of the
agitator
38. The rubber drive boot 87 provides the necessary damping to insure the
smooth transmission of power to the agitator 38. simultaneously with the
rotation of ~e 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 and most
preferably 6-1 with respect to the agitator 38. The resulting rapid rotation
of the fan 80 helps to move air through the agitator 38 and ensure proper
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cooling of the agitator motor 40 during its operation.
In operation, the operator applies a force to the hand grip 22
dependent upon a desired direction of movement of the nozzle assembly
16. If the force exerted on the hand grip 22 is in a forward direction, the
forward switch 23 is closed through contact with the hand grip and the
voltage signal (Vcc) is applied to the first pin of controller 27. The
controller 27 in turn generates an output signal (S 1 } based on the
openlclosed states of the switches 23, 25 which is applied to and directs the
operation of relay 29. In the present scenario with a forward force applied
to the hand grip 22, DC power is applied to the agitator motor 40 such that
the agitator 38 is driven in the forward direction drawing the nozzle
assembly 16 forward.
Conversely, if the force exerted on the hand grip 22 is in a rearward
direction, the rearward switch 25 is closed through contact with the hand
grip and the forward switch remains open or is opened. In response to the
output signal (S1) ofthe controller 27, relay29 operates to direct the DC
power to the agitator motor 40 such that the agitator 38 is driven in a
rearward direction drawing the nozzle assembly 16 rea~wvard.
Once the agitator 38 is rotating, a change in direction initiated by the
operator, i.e., a change in the force exerted on the hand grip 22, is
indicated
to the controller 27 by the forward and rearward switches 23 and 25,
respectively. If the agitator 38 is being driven in a forward direction and
the operator exerts a rearward force on the hand grip 22, the hand grip
travels along the stem 21 of the control handle allowing the forward switch
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23 to open followed by the closure of the rearward switch 25. As the
forward switch 23 opens, the voltage signal (Vcc:) is removed from the first
pin of controller 27 thus changing the controller input. As the rearward
switch closes, the voltage signal (Vcc) is applied to the second pin of
controller 27 again changing the controller input.
Based on the new states of the forward and rearward switches 23
and 25, the controller 27 stops generating the present output signal (S 1 )
thus turning the relay 29 off and removing power from the agitator motor
40. The controller 27 may then generate a new output signal (S 1 ) either
immediately or after a delay period which actuates the relay 29 to direct the
DC power to the agitator motor 40 such that the agitator 38 is driven in the
rearward direction. The delay established by the controller 27 may be
between 0:1 second and 1.0 second to allow the agitator 38 rotating in the
first direction to slow significantly, if not stop, bf;fore DC power is
reapplied to drive the agitator 38 for movement in the second direction and
vice versa. In this manner, overheating of the agitator motor 40 may be
substantially avoided.
The foregoing description of the preferred embodiment of this
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 ara possible in light of the
above teachings. For example, various pressure sensing devices may be
utilized to replace the foavvard and rearward switches which sense changes
in direction initiated by an operator, or a single switch may be utilized to
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sense a change in direction with the agitator rotating in a normally forward
direction. Additionally, different delay timing patterns may be utilized
during a stop, delay, and restart sequence or application of the DC power to
the agitator motor 40 may be incrementally increased over a period of time.
5 Even further, additional switching devices such a.s a FET array, for
example, activated by the controller output signal may be utilized to direct
the DC power to the agitator motor 40. The vacuum cleaner could also be
equipped with multiple agitators rather than a single agitator as illustrated.
The present embodiment was chosen and described to.provide the
10 best illustration of the principles of the 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
15 appended claims when interpreted in accordance with the breadth to which
they are fairly, legally and equitably entitled.
