U.S. patent application number 15/196412 was filed with the patent office on 2017-01-05 for vacuum cleaner with brushroll control.
The applicant listed for this patent is TECHTRONIC INDUSTRIES CO. LTD.. Invention is credited to Evan Gordon, Will Sebastian, Shadi Sumrain, Patrick Truitt.
Application Number | 20170000305 15/196412 |
Document ID | / |
Family ID | 56373189 |
Filed Date | 2017-01-05 |
United States Patent
Application |
20170000305 |
Kind Code |
A1 |
Gordon; Evan ; et
al. |
January 5, 2017 |
VACUUM CLEANER WITH BRUSHROLL CONTROL
Abstract
A vacuum cleaner includes a base having a floor nozzle that
defines a suction chamber, a brushroll driven by a brushroll motor,
and a brushroll motor sensor configured to measure an electrical
current used by the brushroll motor. The vacuum cleaner further
includes a pressure sensor configured to measure an internal
pressure within the vacuum cleaner, and a controller in
communication with the brushroll motor sensor and the pressure
sensor. The controller is operable to control an operating speed of
the brushroll motor based on feedback received from the pressure
sensor and the brushroll motor sensor.
Inventors: |
Gordon; Evan; (Canton,
OH) ; Sebastian; Will; (Sagamore Hills, OH) ;
Truitt; Patrick; (Hudson, OH) ; Sumrain; Shadi;
(Hudson, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TECHTRONIC INDUSTRIES CO. LTD. |
Tsuen Wan |
|
HK |
|
|
Family ID: |
56373189 |
Appl. No.: |
15/196412 |
Filed: |
June 29, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62186998 |
Jun 30, 2015 |
|
|
|
62187001 |
Jun 30, 2015 |
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A47L 5/362 20130101;
A47L 9/1683 20130101; Y02B 40/00 20130101; A47L 5/30 20130101; A47L
9/0477 20130101; A47L 9/30 20130101; Y02B 40/82 20130101; A47L
9/2831 20130101; A47L 9/2821 20130101; A47L 9/248 20130101; A47L
9/0411 20130101; A47L 5/26 20130101; A47L 9/2847 20130101 |
International
Class: |
A47L 9/28 20060101
A47L009/28; A47L 5/26 20060101 A47L005/26; A47L 9/24 20060101
A47L009/24; A47L 9/16 20060101 A47L009/16; A47L 9/04 20060101
A47L009/04; A47L 9/30 20060101 A47L009/30; A47L 5/30 20060101
A47L005/30; A47L 5/36 20060101 A47L005/36 |
Claims
1. A vacuum cleaner comprising: a base including a floor nozzle,
the floor nozzle defining a suction chamber; a brushroll driven by
a brushroll motor; a brushroll motor sensor configured to measure
an electrical current used by the brushroll motor; a pressure
sensor configured to measure an internal pressure within the vacuum
cleaner; and a controller in communication with the brushroll motor
sensor and the pressure sensor, wherein the controller is operable
to control an operating speed of the brushroll motor based on
feedback received from the pressure sensor and the brushroll motor
sensor.
2. The vacuum cleaner of claim 1, further comprising a dirt cup,
wherein the controller is operable to determine a fullness level of
the dirt cup based on feedback received from the pressure
sensor.
3. The vacuum cleaner of claim 1, further comprising a filter,
wherein the controller is operable to determine if the filter is
present based on feedback received from the pressure sensor.
4. The vacuum cleaner of claim 1, further comprising a filter,
wherein the controller is operable to determine if the filter is
clogged based on feedback received from the pressure sensor.
5. The vacuum cleaner of claim 1, further comprising a filter
housing and a filter received within the filter housing, wherein
the pressure sensor is located within the filter housing.
6. The vacuum cleaner of claim 1, wherein the pressure sensor is
located within the floor nozzle.
7. The vacuum cleaner of claim 1, wherein the pressure sensor
includes a housing defining a chamber, a hall-effect sensor, and a
magnet moveable within the chamber relative to the hall-effect
sensor in response to changes in the internal pressure.
8. The vacuum cleaner of claim 1, wherein the pressure sensor
includes a housing including a cap portion connected to a base
portion, a diaphragm supporting a magnet in the housing, the
diaphragm and base portion defining a chamber arranged in fluid
communication with an airflow path of the vacuum cleaner, the
diaphragm moveable within the chamber in response to changes in the
internal pressure of the vacuum cleaner, and a hall-effect sensor
configured to measure a relative distance between the magnet and
the hall-effect sensor.
9. The vacuum cleaner of claim 8, wherein the diaphragm is
sandwiched between the cap portion and the base portion.
10. The vacuum cleaner of claim 1, wherein at least a portion of
the pressure sensor is formed integrally with the base or the
handle of the vacuum cleaner.
11. The vacuum cleaner of claim 1, wherein the pressure sensor is
positioned in fluid communication with an air path of the vacuum
cleaner to provide two or more indications of system performance
selected from a group consisting of system clogged, filter bag
full, dirt bin full, no filter present, no filter bag present, dirt
bin empty, filter bag empty, and normal operation.
12. The vacuum cleaner of claim 1, further comprising a tachometer
configured to measure a speed of the brushroll motor or the
brushroll to help maintain the speed of the brushroll motor or
brushroll, the speed based on the sensed motor current and the
sensed pressure.
13. A method of controlling a brushroll motor in a vacuum cleaner,
the method comprising: sensing a pressure within the vacuum
cleaner; sensing a motor current of the brushroll motor used to
drive a brushroll; comparing the sensed pressure with one or more
reference pressure values; comparing the sensed motor current with
one or more reference current values; and controlling operation of
the brushroll motor based on the sensed pressure and the sensed
motor current, wherein controlling operation of the brushroll motor
includes turning the brushroll motor on based on the sensed
pressure.
14. The method of claim 13, wherein controlling operation of the
brushroll motor further includes altering an operating speed of the
brushroll motor based on at least one of the sensed pressure or
sensed motor current.
15. The method of claim 13, wherein controlling operation of the
brushroll motor further includes turning the brushroll motor off
based on at least one of the sensed pressure or the sensed motor
current.
16. The method of claim 15, wherein turning the brushroll motor off
is based on the sensed pressure.
17. The method of claim 15, wherein turning the brushroll motor off
is based on the sensed motor current.
18. The method of claim 15, wherein turning the brushroll motor off
is based on both the sensed pressure and the sensed motor
current.
19. The method of claim 13, further comprising providing a first
mode in which controlling operation of the brushroll motor further
includes altering an operating speed of the brushroll motor based
on at least one of the sensed pressure or the sensed motor current;
providing a second mode in which controlling operation of the
brushroll motor further includes turning the brushroll motor off
based on at least one of the sensed pressure or the sensed motor
current; and providing a switch to selectively choose the first
mode or the second mode.
20. The method of claim 13, further comprising measuring an
operating speed of the brushroll motor or the brushroll to help
maintain the operating speed of the brushroll motor or brushroll,
the speed of the brushroll motor or brushroll being based on the
sensed motor current or the sensed pressure.
21-43. (canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Patent
Application No. 62/186,998, filed Jun. 30, 2015 and claims priority
to U.S. Provisional Patent Application No. 62/187,001, filed Jun.
30, 2015, the entire contents all of which are hereby incorporated
by reference herein.
BACKGROUND
[0002] The present invention relates to vacuum cleaners, and more
particularly to vacuum cleaners with a brushroll.
SUMMARY
[0003] In one aspect, the invention provides a vacuum cleaner
including a base having a floor nozzle that defines a suction
chamber, a brushroll driven by a brushroll motor, and a brushroll
motor sensor configured to measure an electrical current used by
the brushroll motor. The vacuum cleaner further includes a pressure
sensor configured to measure an internal pressure within the vacuum
cleaner, and a controller in communication with the brushroll motor
sensor and the pressure sensor. The controller is operable to
control an operating speed of the brushroll motor based on feedback
received from the pressure sensor and the brushroll motor
sensor.
[0004] In another aspect, the invention provides a method of
controlling a brushroll motor in a vacuum cleaner. The method
includes sensing a pressure within the vacuum cleaner, sensing a
motor current of the brushroll motor used to drive the brushroll,
comparing the sensed pressure with one or more reference pressure
values, comparing the motor current with one or more reference
current values, and controlling operation of the brushroll motor
based on the sensed pressure and motor current. Controlling
operation of the brushroll motor includes turning the brushroll
motor on based on the sensed pressure.
[0005] In another aspect, the invention provides a method of
controlling a brushroll motor in a vacuum cleaner. The method
includes sensing an electrical current used by the brushroll motor
to drive the brushroll at a first speed, sensing the speed of the
brushroll motor or the brushroll, varying the electrical current to
maintain the first speed of the brushroll, and determining a change
in current drawn by the brushroll motor to maintain the first speed
of the brushroll. The method also includes comparing the change in
current to a threshold current change value, maintaining the first
brushroll speed when the change in current is less than the
threshold current change value, and maintaining a second brushroll
speed different than the first brushroll speed when the change in
current is greater than the threshold current change value.
[0006] Other aspects of the invention will become apparent by
consideration of the detailed description and accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a perspective view of a vacuum cleaner according
to an embodiment of the invention.
[0008] FIG. 2 is a perspective view of a base of the vacuum cleaner
of FIG. 1, with a portion removed.
[0009] FIG. 3 is a bottom view of the base of FIG. 2.
[0010] FIG. 4 is a top view of the base of FIG. 2, with a portion
removed.
[0011] FIG. 5 is a perspective view of the base of FIG. 2, with a
portion removed.
[0012] FIG. 6 is a perspective view of a portion of a pressure
sensor used in the base of FIG. 2.
[0013] FIG. 7 is a perspective view of a portion of the pressure
sensor used in the base of FIG. 2.
[0014] FIG. 8 is a perspective view of a portion of the pressure
sensor used in the base of FIG. 2.
[0015] FIG. 9 is a cross-sectional view of a portion of the base of
FIG. 2.
[0016] FIG. 10 is a graph illustrating suction and brushroll motor
data for a vacuum cleaner passing from carpet to hard floor.
[0017] FIG. 11 is a block diagram illustrating the interaction
between various sensors, a controller, and brushroll elements.
[0018] FIG. 12 is a perspective view of a pressure sensor according
to another embodiment.
[0019] FIG. 13 is a cross-sectional view of the pressure sensor of
FIG. 12.
[0020] FIG. 14 is an exploded view of a portion of the pressure
sensor of FIG. 12.
[0021] FIG. 15 is a graph illustrating pressure and voltage
correlation data for the pressure sensor of FIG. 11 in a variety of
operating conditions.
[0022] Before any embodiments of the invention are explained in
detail, it is to be understood that the invention is not limited in
its application to the details of construction and the arrangement
of components set forth in the following description or illustrated
in the following drawings. The invention is capable of other
embodiments and of being practiced or of being carried out in
various ways.
DETAILED DESCRIPTION
[0023] FIG. 1 illustrates an exemplary vacuum cleaner 10. The
illustrated vacuum cleaner 10 is an upright vacuum cleaner and
includes a base assembly 14 and a handle assembly 18 pivotally
coupled to the base assembly 14. In other embodiments, other types
and styles of vacuum cleaners can be utilized (e.g., canister,
handheld, utility, etc.).
[0024] In the illustrated embodiment of the vacuum cleaner 10, the
base assembly 14 is movable along a surface to be cleaned, such as
a carpeted or hard-surface floor. The handle assembly 18 extends
from the base assembly 14 and allows a user to move and manipulate
the base assembly 14 along the surface. The handle assembly 18 is
also movable relative to the base assembly 14 between an upright
position (FIG. 1) and an inclined position (not shown).
[0025] The handle assembly 18 includes a maneuvering handle 22
having a grip 26 for a user to grasp and maneuver the vacuum
cleaner 10. In the illustrated embodiment, the vacuum cleaner 10
also includes a detachable wand 30. The wand 30 may be used to
clean above-floor surfaces (e.g., stairs, drapes, corners,
furniture, etc.). An accessory tool 34 (e.g., a crevice tool, an
upholstery tool, a pet tool, etc.) is detachably coupled to the
handle assembly 18 for storage and may be used with the wand 30 for
specialized cleaning.
[0026] With continued reference to FIG. 1, a canister 38 is
supported on the handle assembly 18 and includes a separator 42 and
a dirt cup 46. The separator 42 removes dirt particles from an
airflow drawn into the vacuum cleaner 10 which are then collected
by the dirt cup 46. The separator 42 may be a cyclonic separator,
filter bag, or other separator as desired. In the illustrated
embodiment, the canister 38 including the dirt cup 46 is removable
from the handle assembly 18 to facilitate emptying the dirt
particles from the dirt cup 46.
[0027] The vacuum cleaner 10 further includes a suction motor (not
shown) contained within a motor housing 54 (FIG. 1) and a suction
source (not shown), such as an impeller fan assembly, driven by the
suction motor. The suction motor selectively receives power from a
power source (e.g., a cord for plugging into a source of utility
power, a battery, etc.) to generate the suction airflow through the
vacuum cleaner 10.
[0028] Now referring to FIGS. 2-4, the base assembly 14 includes a
suction nozzle or floor nozzle 58 having a suction chamber 70 (FIG.
3). In the illustrated embodiment, the suction chamber 70 is formed
between an upper portion 62 and a lower portion 66 of the floor
nozzle 58 (FIG. 2). Air and debris may be drawn into the suction
chamber 70 through an elongate inlet opening 74 in the lower
portion 66 (FIG. 3). In the illustrated embodiment, a plurality of
cross bars 78 are positioned across the opening 74 inhibiting
ingress of electrical cords and other objects into the opening 74.
In other embodiments, the cross bars 78 may be omitted. After
entering the suction chamber 70, air and debris pass through a
nozzle outlet 82 that fluidly communicates with the separator
42.
[0029] Optionally, the base assembly 14 includes a pair of rear
wheels 86 and a pair of forward supporting elements or wheels 90
spaced from the rear wheels 86 and located generally adjacent the
inlet opening 74. The wheels 86, 90 facilitate movement of the base
assembly 14 along the surface to be cleaned. In addition, the
forward wheels 90 may assist in positioning the inlet 74 of the
floor nozzle 58 at a desired height above the surface to be
cleaned.
[0030] With reference to FIG. 3, an agitator or brushroll 94 is
rotatably supported at its ends within the nozzle suction chamber
70. The brushroll 94 includes an array of bristle tufts 98 or other
protrusions that may extend through the opening 74 to agitate the
surface to be cleaned. The agitator 94 is rotatably driven by a
drive belt 106 (FIG. 4) that receives power from a brushroll motor
108. In the illustrated embodiment, the brushroll motor 108 drives
the brushroll 94, while the suction motor drives the suction
source. In other embodiments, a single motor may be provided to
drive the suction source and the brushroll 94.
[0031] With reference to FIG. 4, the floor nozzle 58 also includes
a pressure sensor 110. The illustrated pressure sensor 110 is in
communication with the suction chamber 70 (FIG. 3) for determining
a nozzle suction pressure within the floor nozzle 58.
Alternatively, the pressure sensor 110 can be used to determine a
nozzle suction pressure in any other type of nozzle, such as an
accessory wand or other above-floor cleaning attachment. The
illustrated pressure sensor 110 is disposed proximate the suction
chamber 70; however, in other embodiments, the pressure sensor 110
can be located remote from the suction chamber 70. In such
embodiments, the pressure sensor 110 can monitor the nozzle suction
pressure via a tube or other suitable means having an end exposed
to the suction chamber 70.
[0032] The illustrated pressure sensor 110 includes a pressure
sensor housing 114 (FIG. 5) defining a chamber that is at least
partially enclosed by a pressure sensor cap portion 118. The upper
portion 62 of the floor nozzle 58 includes an aperture between the
pressure sensor housing 114 and the suction chamber 70 forming a
pressure sensor inlet 122 (FIGS. 8 and 9) to allow for fluid
communication between the pressure sensor 110 and the suction
chamber 70. With reference to FIG. 5, the housing includes an
internal wall 126 dividing the inner chamber of the pressure sensor
110 such that the inlet 122 is at least partially isolated from the
remainder of the pressure sensor 110. The internal wall 126
includes an aperture that allows for fluid communication between
the inlet 122 and the remainder of the pressure sensor 110 while
providing a barrier to inhibit the intake of dust particles and
debris flowing through the suction chamber 70. In the illustrated
embodiment, the aperture is a U-shaped opening in the internal wall
126.
[0033] Referring to FIGS. 8 and 9, the pressure sensor 110 also
includes an inlet guard 130 positioned adjacent to the inlet 122 to
further limit the intake of dust particles and debris into the
pressure sensor 110. The inlet guard 130 may attach to the inlet
122. Further, the inlet guard 130 may be shaped in various ways to
provide desirable flow characteristics within the suction chamber
70 and/or the chamber of the pressure sensor 110. For example, the
illustrated inlet guard 130 provides a sloped surface 134 such that
the area of the inlet 122 decreases in a direction toward the
interior of the pressure sensor 110, allowing fewer particles to
enter the pressure sensor chamber.
[0034] The pressure sensor housing 114 may be integrally formed in
the floor nozzle 58. The pressure sensor housing 114 may be
integrally formed in the upper portion 62. Alternatively, the
pressure sensor housing 114 may be a separate component assembled
to the vacuum cleaner 10. Alternatively or additionally, the air
inlet 122 of the pressure sensor 110 may be configured as a
fitting, optionally with a barb feature at an end of the fitting,
or a threaded fitting, or compression fitting, or other fitting, to
be in fluid communication with the suction chamber 70 using a duct
or a tube connected to the fitting.
[0035] With reference to FIGS. 6 and 7, the illustrated pressure
sensor 110 also includes a piston block 138 holding a magnet 142
that is movable with respect to a hall-effect sensor 150. In the
illustrated embodiment, the hall-effect sensor 150 is mounted to a
circuit board 146. The piston block 138 is forced toward the
hall-effect sensor 150 by a spring (not shown), which may be
positioned between the internal wall 126 and the piston block 138,
while negative pressure within the suction chamber 70 generated by
the suction source pulls on the piston block 138, tending to
overcome the force of the spring and move the piston block 138 and
magnet 142 away from the sensor 150. Therefore, the relative
distance of the piston block 138 from the hall-effect sensor 150
can be correlated to the suction pressure within the chamber 70.
Specifically, the higher the suction (i.e., the lower the pressure)
within the suction chamber 70, the further the piston block 138
moves away from the sensor 150 against the force of the spring, and
vice versa. The hall-effect sensor 150 and magnet 142 are used to
determine the relative distance between the piston block 138 and
the sensor 150 to compute a sensed pressure. It should be
understood that in other embodiments, other types of pressure
sensors may be used, such as optical, piezoresistive, and the
like.
[0036] With reference to FIG. 11, the vacuum cleaner 10 further
includes a brushroll motor sensor 133 and a controller 116 in
communication with the sensors 110, 133. The brushroll motor sensor
133 can be configured to sense a torque output or current draw of
the brushroll motor 108. The controller 116 can receive and analyze
data from the pressure sensor 110 and the brushroll motor sensor
133 and use some or all of that data as feedback to control the
rotational speed of the brushroll motor 108.
[0037] In general operation, the suction motor drives the fan
assembly or suction source to generate airflow through the vacuum
cleaner 10. The airflow enters the floor nozzle 58 through the
inlet opening 74 and flows into the suction chamber 70 (FIG. 3).
The airflow and any debris entrained therein then travel through
the nozzle outlet 82 and into the separator 42. After the separator
42 filters or otherwise cleans the airflow, the cleaned airflow is
directed out of the canister 38 and into the motor housing 54,
(e.g., through an airflow channel extending through the handle
assembly 18) (FIG. 1). The cleaned airflow is ultimately exhausted
back into the environment through air outlet openings.
[0038] With reference to FIG. 11, during operation, the controller
116 receives the data from the sensors 110, 133 and compares the
sensed pressure from the pressure sensor 110 and the sensed current
and/or torque values from the brushroll motor sensor 133 with one
or more corresponding predetermined thresholds. The predetermined
thresholds (i.e., pressure, torque, and/or current) are associated
with different floor types to represent a distinction between floor
surfaces (e.g., carpet and hard floor). The controller 116
determines the floor surface by comparing the sensed pressure and
the sensed motor current and/or torque values with the
predetermined thresholds, and automatically operates the brushroll
motor 108, and optionally the suction motor, in a manner optimized
for the type of floor surface. For example, high-pile carpet will
generally cause high suction (i.e., low pressure) within the
suction chamber 70 and force the brushroll motor 108 to work harder
(i.e., generate higher torque and draw more current), while a hard
floor surface will lead to lower suction (i.e., higher pressure
that is closer to atmospheric pressure) within the suction chamber
70 and will allow the brushroll motor 108 to work more easily
(i.e., generate lower torque and draw less current).
[0039] FIG. 10 illustrates exemplary suction and brushroll motor
data for a vacuum cleaner passing from carpet to hard floor.
Depending on the comparison of the sensed pressure, torque, and/or
current with their corresponding threshold values, the controller
116 operates the brushroll motor 108 in a desired state to drive
the brushroll motor 108 at a desired speed. For example, the
controller 116 may operate the brushroll motor 108 at a slow
rotational speed when the floor nozzle 58 is located on a hard
floor surface to reduce scattering of debris and reduce energy
consumed by the brushroll motor 108. Further, the controller 116
may operate the brushroll motor 108 at a high rotational speed
while the floor nozzle 58 is on carpet to better agitate dust
particles out of the carpet fibers. Alternatively, the controller
116 may shut off the brushroll motor 108 when the floor nozzle 58
is located on certain surfaces (e.g., hard floor), to conserve
energy, reduce scattering of debris, and/or reduce wear on delicate
surfaces.
[0040] The controller 116 may also or alternatively operate the
suction motor based on floor type. For example, the controller 116
may operate the suction motor at a lower power on a hard floor
surface to conserve energy or a higher power on a hard floor
surface to increase debris pick-up. In some embodiments, the
suction motor may be operated at a lower power on certain height
carpets to reduce the clamp-down of the nozzle 58 to the carpet so
that the vacuum cleaner 10 is easier to push.
[0041] By continuously or intermittently monitoring pressure and
motor current and/or torque using data from the sensors 110, 133,
the controller 116 determines when the vacuum 10 passes from one
surface type to another surface type and alters the brushroll
speed, and optionally suction, to provide a pre-programmed vacuum
cleaner operation in response to the different conditions created
by different floor types. Either or both of the pressure sensor 110
and the brushroll motor sensor 133 may be continually used to alter
the rotational speed of the brushroll motor 108 in response to the
sensed data. If the brushroll motor 108 is off, however, only the
pressure sensor 110 is used to determine a change in floor
type.
[0042] Referring to FIG. 11, a switch 112 may be provided to allow
a user to selectively switch between different modes of operation,
such as to put the vacuum cleaner 10 in a "speed control mode." in
which the controller 116 changes the rotational speed of the
brushroll motor 108 (and the brushroll 94) in response to the
sensed data, or in an "on/off mode", in which controller 116 turns
the brushroll motor 108 on or off in response to the sensed data.
Such a switch may be positioned for easy access by a user for
changing the operational mode of the vacuum cleaner 10. In certain
applications, either the speed control mode or the on/off mode may
be preferred by the manufacturer, and the switch 112 may be
positioned in a less accessible location to a user, such as behind
a cover so that the switch 112 may be accessible to a user only if
the cover or other portion of the floor nozzle 58 is removed. In
some embodiments, the switch 112 is provided on the circuit board
146.
[0043] While the vacuum cleaner 10 is operated in the "speed
control mode," the pressure sensor 110 and the brushroll motor
sensor 133 continuously or intermittently provide sensed data
representative of the suction pressure and the motor current and/or
torque, as described above. When the sensed data of the pressure
sensor 110 and the brushroll motor sensor 133 correspond to the
values associated with the vacuum cleaner 10 operating on a carpet
surface, or the like, the controller 116 operates the brushroll
motor 108 at a first rotational speed, for example, between about
1000 and 5000 revolutions per minute (RPM), or between about 2000
and 4000 RPM. When the sensed data of the pressure sensor 110 and
the brushroll motor sensor 133 correspond to the values associated
with the vacuum cleaner 10 operating on a hard floor surface, or
the like, the controller 116 operates the brushroll motor 108 at a
second rotational speed that is lower than the first rotational
speed, for example, between about 100 and 1000 RPM, or between
about 300 and 600 RPM. Either or both of the pressure sensor 110
and the brushroll motor sensor 133 may be continually or
intermittently used to alter the rotational speed of the brushroll
motor 108 in response to the sensed data. In alternative
embodiments, either the pressure sensor 110 or the brushroll motor
sensor 133 may be omitted so that only the other of the pressure
sensor 110 or the brushroll motor sensor 133 provides feedback used
to alter the rotational speed of the brushroll motor 108.
[0044] While the vacuum cleaner 10 is in the "on/off mode," the
pressure sensor 110 continually monitors the nozzle suction
pressure; however, the brushroll motor sensor 133 may monitor the
motor current and/or torque when the brushroll motor 108 is on.
When the brushroll motor 108 is off, the motor current and/or
torque will not provide data useful in determining the type of
floor surface the floor nozzle 58 is on. When the sensed data of
the pressure sensor 110 and the brushroll motor sensor 133
correspond to the values associated with the vacuum cleaner 10
operating on a carpet surface, the controller 116 operates the
brushroll motor 108 (and the brushroll 94) at a first rotational
speed. When the sensed data of the pressure sensor 110 and the
brushroll motor sensor 133 correspond to the values associated with
the vacuum cleaner 10 operating on a hard floor surface, or the
like, the controller 116 turns the brushroll motor 108 off. While
the floor nozzle 58 is operating on the hard floor surface and the
brushroll motor 108 is off, the controller 116 relies on the
pressure sensor 110 alone to determine whether to turn the
brushroll motor 108 on. The controller 116 may use either or both
of the sensors 110, 133, to determine whether to turn the brushroll
motor 108 off.
[0045] In some embodiments, the vacuum cleaner 10 further includes
a tachometer 155 that measures a rotational speed of the brushroll
motor 108 or the brushroll 94 during operation (FIG. 11). The
tachometer 155 can include one or more hall-effect sensors, optical
encoders, or any other type of sensor suitable for measuring
rotational speed.
[0046] The sensed brushroll speed data from the tachometer 155 can
be used by the controller 116 in conjunction with data from the
brushroll motor sensor 133 to maintain a relatively constant
rotational speed of the brushroll 94. For example, when the
brushroll 94 encounters increased resistance, such as when
transitioning from a hard floor surface to a carpeted floor
surface, the controller 116 may increase the current supplied to
the brushroll motor 108 to increase the torque output by the
brushroll motor 108. When the brushroll 94 encounters decreased
resistance, such as when transitioning from a carpeted floor
surface to a hard floor surface, the controller 116 may decrease
the current supplied to the brushroll motor 108 to decrease the
torque output by the brushroll motor 108. In such embodiments, the
controller 116 compares the amount of current increase or decrease
needed to maintain the speed of the brushroll 94 and compares the
amount to a threshold current change value. If the current increase
or decrease exceeds the threshold current value, then the
controller 116 operates the brushroll 94 at a second speed instead
of the first speed.
[0047] As the vacuum cleaner 10 passes from one surface type to
another, the controller 116 uses the amount of current change
needed to maintain a constant brushroll speed, as well as whether
the current change is an increase or decrease to determine the kind
of floor type the vacuum cleaner 10 is operating on, and the
controller 116 adjusts the current supplied to the brushroll motor
108 to maintain the speed of the brushroll 94 at a speed desired
for the particular floor type. In this way, the controller 116
determines the type of floor surface using the change in brushroll
motor current needed to maintain a speed compared to predetermined
thresholds and automatically operates the brushroll motor 108, and
optionally the suction motor, in a manner corresponding to the type
of floor surface. In some cases, the controller 116 may turn off
the brushroll motor 108 if the current exceeds the threshold
current value. The controller 116 may include overload protection
programming.
[0048] FIGS. 12-14 illustrate a pressure sensor 110' according to
another embodiment that can be used in conjunction with the vacuum
cleaner 10 (e.g., instead of the pressure sensor 110 or in addition
to the pressure sensor 110).
[0049] The pressure sensor 110' includes a base portion 120' and a
cap portion 118' that cooperate to define a pressure sensor housing
114'. In some embodiments, the base portion 120' is integrally
formed with a wall bounding the airflow path of the vacuum cleaner
10. The housing 114' contains a diaphragm 123' holding a magnet
142' that is movable with respect to the housing 114' when the
diaphragm 123' flexes (FIG. 13). The diaphragm 123' is sandwiched
between the base portion 120' and the cap portion 118' such that
the diaphragm 123' creates a substantially airtight seal between
the base portion 120' and the cap portion 118'. Accordingly, the
diaphragm 123' is subject to pressure forces resulting from any
pressure imbalance between air contained within the base portion
120' and air contained within the cap portion 118'.
[0050] The air inlet of the pressure sensor 110' is configured as a
fitting 125', such as a hose barb or nipple, a threaded fitting,
compression fitting, or other fitting. In the illustrated
embodiment, the fitting 125' extends from the base portion 120'.
The fitting 125' can be integrally formed with the base portion
120' as a single piece, or alternatively, the fitting 125' can be
formed separately and attached to the base portion 120' by threads
or another type of suitable airtight connection. The fitting 125'
(i.e. the air inlet for the pressure sensor 110') is in fluid
communication with the suction chamber 70 such that the pressure at
the sensor air inlet is representative of the pressure within the
suction chamber 70. In some embodiments, the fitting 125' receives
one end of a tube (not shown) that extends to the suction chamber
70 (e.g., to the pressure sensor inlet 122 (FIGS. 8 and 9) on the
upper portion 62 of the floor nozzle 58) to allow for fluid
communication between the pressure sensor 110' and the suction
chamber 70. In other embodiments, the pressure sensor 110' can be
directly connected to the suction chamber 70.
[0051] In the illustrated embodiment, a hall-effect sensor 150' is
located on the cap portion 118' (FIG. 13). The hall-effect sensor
150' may be incorporated onto a circuit board 146'. Alternatively,
all or a portion of the hall-effect sensor may be positioned on or
adjacent the cap portion 118' and electrically connected to a
circuit board positioned in a separate location. The cap portion
118' may include attachments for securing the circuit board 146' or
the hall-effect sensor 150' to the cap portion 118'. In other
embodiments, the hall-effect sensor 150' can be located on the base
portion 120'. Negative pressure within the suction chamber 70
generated by the suction source pulls on the diaphragm 123',
causing it to deform and move magnet 142' away from the circuit
board 146' and the hall-effect sensor 150'. Therefore, the relative
distance of magnet 142' from the hall-effect sensor 150' is
correlated to the suction pressure within the chamber 70.
Specifically, the higher the suction (i.e., the lower the pressure)
within the suction chamber 70, the further the magnet 142' moves
away from the hall-effect sensor 150', and vice versa. Accordingly,
the hall-effect sensor 150' is used to determine a sensed
pressure.
[0052] In some embodiments, the diaphragm 123' is a first diaphragm
123' that is interchangeable with a second diaphragm (not shown)
having different deflection characteristics under pressure. In such
embodiments, the first and second diaphragms can be interchanged in
order to vary the responsiveness or operating pressure range of the
pressure sensor 110'. In one embodiment, the first diaphragm 123'
has a first attribute selected from a group consisting of
thickness, durometer, shape, and material, and where the first
diaphragm is replaceable with a second diaphragm having a second
attribute selected from a group consisting of thickness, durometer,
shape, and material. For example, the first diaphragm 123' may be
made from a polyurethane material and the second diaphragm may be
made from butyl rubber providing different response
characteristics. In another example, the first diaphragm 123' may
have a flat shape or uniform thickness and the second diaphragm may
have a concave shape that is thicker near its perimeter, or
alternatively thinner near its perimeter, providing different
response characteristics, or in yet another alternative, the second
diaphragm may have a shape having ribs, apertures, protrusions,
grooves, or other shapes. In another example, the first diaphragm
123' may have a durometer of 25 Shore A and the second diaphragm
may have a durometer of 40 Shore A, providing different response
characteristics. In another example, the second diaphragm may be
thinner than the first diaphragm 123' and therefore experience
greater deflection than the first diaphragm 123' at a particular
pressure difference between the base portion 120' and the cap
portion 118'.
[0053] For particular embodiments, the diaphragm 123' may be made
from materials such as butyl rubber, polyurethane, silicone rubber,
and other synthetic rubbers, thermoplastic elastomer (TPE), rubber,
thermoplastic vulcanizates (TPV), thermoplastics, and other
materials to provide response characteristics under pressure as
desired for the application. The diaphragm 123' may have a
durometer between about 15 and 80 Shore A, or for particular
embodiments between about 20 and 40 Shore A, or other hardnesses as
desired to provide response characteristics under pressure as
desired for the application. In one embodiment, the diaphragm 123'
is a thermoplastic elastomer having a durometer between 20 and 30
Shore A.
[0054] It was found that the pressure sensor 110, 110' positioned
in the air flow path of the vacuum cleaner 10 can be used indicate
more than one system condition, as shown in FIG. 15. For example,
if the user does not install a filter (e.g., a pre-motor filter or
a post-motor filter in some embodiments), the pressure reading at
the sensor 110, 110' will be higher than if the filter were
installed. When the pressure exceeds a predetermined threshold, the
controller 116 may illuminate a signal to the user indicating that
the filter is missing, and/or may turn off the suction motor to
prevent damage to the vacuum cleaner 10.
[0055] Another common condition occurs when the dirt cup 46 is
filled with debris and needs to be emptied. The pressure reading at
the sensor 110, 110' decreases as the dirt cup 46 fills, and when
the pressure reaches a predetermined value, the controller 116 may
illuminate a signal to the user indicating that the dirt cup 46 is
full, and/or may turn off the suction motor. When the sensor 110,
110' indicates a normal operating pressure, the controller 116 may
provide a signal, such as a light or other display, to the user to
indicate that the vacuum 10 is operating normally.
[0056] In certain conditions, the vacuum cleaner 10 may pick up a
large object or enough debris to form a blockage in the air path,
or a filter or filter bag in the vacuum may become clogged (i.e.
may contain enough debris that vacuum cleaner performance is
reduced). When a clog occurs, the system pressure, as measured by
the sensor 110, 110', drops. When the pressure drops to a
predetermined level, the controller 116 may provide a signal such
as a light or other display to the user indicating that a clog has
developed, and/or may turn off the suction motor.
[0057] Accordingly, one pressure sensor 110, 110' may be positioned
in fluid communication with the air path of the vacuum cleaner 10
to provide system information for a variety of operating
conditions. In one embodiment, one pressure sensor 110, 110' may be
positioned in fluid communication with the air path of the vacuum
cleaner 10 to provide two or more indications of system performance
selected from a group consisting of system clogged, filter bag
full, dirt bin full, no filter present, no filter bag present, dirt
bin empty, filter bag empty, and normal operation. Alternatively,
one pressure sensor 110, 110' may be positioned in fluid
communication with the air path of the vacuum cleaner 10 to provide
three or more indications of system performance selected from a
group consisting of system clogged, filter bag full, dirt bin full,
no filter present, no filter bag present, dirt bin empty, filter
bag empty, and normal operation. In yet another alternative, one
pressure sensor 110, 110' may be positioned in fluid communication
with the air path of the vacuum cleaner 10 to provide four or more
indications of system performance selected from a group consisting
of system clogged, filter bag full, dirt bin full, no filter
present, no filter bag present, dirt bin empty, filter bag empty,
and normal operation. In such embodiments, the controller 116
continuously or periodically monitors the pressure sensor and
provides a signal such as a light or other display to the user
indicating a system condition, and/or may turn off the suction
motor.
[0058] Various features and advantages of the invention are set
forth in the following claims.
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