TECHNICAL FIELD
[0001] This disclosure relates to floor cleaning using a cleaning pad.
BACKGROUND
[0002] Tiled floors and countertops routinely need cleaning, some of which entails scrubbing
to remove dried in soils. Various cleaning implements can be used for cleaning hard
surfaces. Most implements include a cleaning pad that may be removably attached to
the implement. The cleaning pads may be disposable or reusable. In some examples,
the cleaning pads are designed to fit a specific implement or may be designed for
more than one implement.
[0003] Traditionally, wet mops are used to remove dirt and other dirty smears (e.g., dirt,
oil, food, sauces, coffee, coffee grounds) from the surface of a floor. A person usually
dips the mop in a bucket of water and soap or a specialized floor cleaning solution
and rubs the floor with the mop. In some examples, the person may have to perform
back and forth scrubbing movements to clean a specific dirt area. The person then
dips the mop in the same bucket of water to clean the mop and continues to scrub the
floor. Additionally, the person may need to kneel on the floor to clean the floor,
which could be cumbersome and exhausting, especially when the floor covers a large
area.
[0004] Floor mops are used to scrub floors without the need for a person go on their knees.
A pad attached to the mop or an autonomous robot can scrub and remove solids from
surfaces and prevents a user from bending over to clean the surface, which prevents
a injuries to the user.
[0005] JP 2012 176279 A discloses an autonomous coverage robot comprising a chassis, a drive system, a vacuum
assembly comprising a collection region engaging the cleaning surface and a suction
region in fluid communication with the collection region, a collection volume for
collecting waste removed by the vacuum assembly, a supply volume configured to hold
a cleaning liquid, an applicator configured to dispense the cleaning liquid onto the
cleaning surface, and a wetting element engaging the cleaning surface to distribute
the cleaning liquid.
US 2009/281661 A1 discloses a robotic cleaner including a cleaning assembly for cleaning a surface
and a main robot body. The main robot body houses a drive system to cause movement
of the robotic cleaner and a microcontroller to control the movement of the robotic
cleaner. The cleaning assembly is located in front of the drive system and a width
of the cleaning assembly is greater than a width of the main robot body. A robotic
cleaning system includes a main robot body and a plurality of cleaning assemblies
for cleaning a surface.
SUMMARY
[0006] The present invention relates to a mobile floor cleaning robot as set out in claim
1. Other embodiments are described in the dependent claims. A surface cleaning pad
is described including an absorbent core containing fiber material which absorbs and
retains liquid material, a liner layer (also herein throughout called a "wrap layer")
in contact with and covering at least one side of the absorbent core, containing fiber
material which retains and wicks liquid material through the liner layer. In embodiments,
the cleaning pad is disposable or washable and reusable.
When a pad 100 is damp, not enough fluid is present to lubricate the interface between
the bottom surface of the pad and the floor surface. A fully wetted pad will ride
on a layer of fluid while the pad is moving over a floor surface, but as the damp
pad slowly absorbs fluid, the not fully wet, not fully lubricated, wrap layer will
drag on the floor surface. In implementations, the spunbond or spunlace wrap layer
is manufactured with hydrophilic fibers that minimize the surface area of the pad
exposed to air between the pad and the floor surface. A wet pad would stick to the
hydrophilic floor surface if the indentations or needle punches were not part of the
wrap layer. Applying a surface texture to the spunbond or spunlace of the wrap layer,
such as a herringbone indentation patter or a square grid indentation pattern, breaks
the surface tension that would otherwise case a wet pad to stick to a wet floor surface.
[0007] In implementations of the pad, the liner layer includes meltblown abrasive fibers
adhered to the side of the liner layer not in contact with the absorbent core; the
pad described above where the meltblown fibers have a diameter of between about 0.1
µm and about 20 µm; the pad described above where the meltblown abrasive fibers cover
between about 44 percent and about 75 percent of the surface of the liner layer; In
implementations of the pad, the meltblown abrasive fibers cover between about 50%
and about 60% of the surface of the liner layer. The meltblown layer provides the
pad with the advantages of breaking surface tension that might otherwise cause the
wet wrap layer to stick to a wet floor. By adding texture and topography to a floor
facing surface of the pad, the meltblown layer prevents the pad from sticking or encountering
high drag forces. The meltblown layer also provides the pad with surface texture for
roughing up dirt and debris stuck or dried to a floor surface and loosening dirt and
debris for absorption by the airlaid inner core of the pad. In implementations of
the pad the meltblown abrasive fibers and the liner layer have a collective thickness
of between about 0.5 mm (millimeter) and about 0.7 mm. In other words, the maximum
overlapped thickness from the outer layer of the applied meltblown to the surface
of the wrap layer is 0.7mm. In implementations of the pad, the wrap layer has a thickness
of between about 0.5 mm and about 0.7mm. In implementations, the wrap layer has a
Worldwide Strategic Partners (WSP) 10.1(05) nonwoven materials water absorption test
specification value of about 600%; the pad described above where the pad increases
in thickness by less than 30% after liquid material absorption. In implementations,
the pad additionally contains one or more of a scent agent, cleaning agent, surfactant,
foaming agent, glossing agent, chemical preservative, debris retention agent (such
as DRAKESOL) and/or anti-bacterial agent. In implementations, the absorbent core comprises
a first airlaid layer adhered to a second airlaid layer and the second airlaid layer
is adhered to a third airlaid layer.
[0008] Fluid wicks between the three layers and is retained uniformly vertically throughout
the stack of airlaid layers without leaking back onto a floor surface beneath the
cleaning pad while downward force is applied to the pad. The surface tension the top
and bottom surfaces of each airlaid layer helps retain wicked fluid within each layer
such that as the top layer fully saturates, no fluid will leak down to the middle
airlaid layer through the bottom surface 11b of the top airlaid layer, and as the
middle airlaid layer fully saturates, no fluid will leak down to the bottom layer
through the bottom surface of the middle (or second) layer.
[0009] In implementations, the pad soaks up 8-10 times its weight in fluid into a relatively
rigid matrix of airlaid layers that does not deform in any dimension when fully wet,
and fluid absorption is achieved through capillary wicking, not by compress-release
drawing because robot to which the pad is attached exerts very light, low variability
cycle weight, not a cycle of heavy human push down and draw back. Each of airlaid
layer slows down penetration of wicked fluid to the next adjacent airlaid layer such
that early cycles of fluid application do not lead to the pay quickly sopping up all
the fluid that is applied to the floor surface. The vertical stack of airlaid layers
provides a resistance to puddling at the bottom of the airlaid core comprising the
three airlaid layers. Each of the of airlaid layers has its own puddle resisting bottom
surface for preventing puddling of absorbed fluid all the way down at the bottom of
the bottom surface of the bottom (or third) layer.
[0010] In implementations, the airlaid layers are of non-uniform hardness or density in
the vertically direction such the outer top and bottom surfaces are harder than the
interior of each layer. In embodiments, as a characteristic of the manufacturing process,
the airlaid layers are of non-uniform surface density such that the outer top and
bottom surfaces are smoother and less absorptive than the interior of each layer.
By varying the surface density at the outer surfaces of each of the airlaid layer,
the airlaid layers remain absorptive, wicking fluid into each airlaid layer without
leaking back through the bottom surfaces. By incorporating three such airlaid layers
into the absorptive core of the pad, the pad therefore has superior fluid retention
properties over a pad having a single core of thickness equivalent to the three layer
stacked core. The three airlaid layers provide at least triple the amount of surface
tension for
[0011] In implementations of the pad, the three airlaid layers are adhered to each other
by means of an adhesive material. In some implementations, the adhesive material is
applied in at least two evenly spaced strips along the length of at least one side
of an airlaid layer and covers not more than 10% of the surface area of the at least
one side. In implementations, of the pad the adhesive material is sprayed on the length
of at least one side of an airlaid layer and covers not more than 10% of the surface
area of the at least one side. In implementations of the pad, at least one airlaid
layer comprises a cellulose based textile material. In some implementations, at least
one airlaid layer, and preferably all three airlaid layers, comprises wood pulp. In
some implementations, one or more of the airlaid layers comprises biocomponent polymers,
cellulose, and latex and the polymer is present in an amount up to about 15% by weight.
[0012] The fluid applicator applies fluid to a floor surface area in front of the cleaning
pad and in the forward drive direction of the mobile robot, and the fluid is applied
to a floor surface area previously occupied by the cleaning pad. In implementations,
the previously occupied floor surface area is stored on a map accessible to the controller
circuit. In implementations, fluid is applied to a floor surface area the robot has
backed away from by a distance of at least one robot footprint length immediately
prior to applying fluid so that the fluid is only applied to traversable floor and
not to a wall, piece of furniture, carpet or other non- floor area that triggers a
bump sensor (collision) switch or proximity sensor on the robot. In implementations,
executing the cleaning routine further comprises moving the cleaning pad in a birdsfoot
motion forward and backward along a center trajectory, forward and backward along
a trajectory to a left side of and heading away from a starting point along the center
trajectory, and forward and backward along a trajectory to a right side of and heading
away from a starting point along the center trajectory. The robot drive comprises
right and left drive wheels disposed on corresponding right and left portions of the
robot body, and a center of gravity of the robot is positioned forward of the drive
wheels, causing a majority of an overall weight of the robot to be positioned over
the pad holder. Because the pad does not expand during fluid absorption, the weight
of the robot remains positioned over the pad holder throughout the cleaning routine.
The overall weight of the robot is distributed between the pad holder and the drive
wheels at a ratio of 3 to 1. In implementations, the robot body and the pad holder
both define substantially rectangular foot prints. Additionally, in implementations,
the robot further includes a vibration motor disposed on a top portion of the pad
holder. In some implementations, the robot further includes a toggle button for actuating
the pad holder release mechanism and ejecting the pad. A backing layer on the pad
engages with the pad holder, and the pad holder comprises raised protrusions positioned
for aligning to and engaging with one or more shaped slots cut out of the backing
layer along a peripheral edge of the backing layer. In some implementations, the pad
holder comprises raised protrusions positioned for aligning to and engaging with one
or more shaped slots cut out of the backing layer at a location other than along a
peripheral edge.
[0013] A method of cleaning a surface with mobile floor cleaning robot is also described
as set out in independent claim 12. Other embodiments are described in the dependent
claims.
[0014] In some implementations, the robot includes a toggle button for actuating the pad
holder release mechanism and ejecting the pad. In some implementations, the pad includes
a backing layer for engaging with the pad holder and the pad holder comprises raised
protrusions positioned for aligning to and engaging with shaped slots cut out of the
backing layer.
[0015] One aspect of the disclosure provides a mobile floor cleaning robot having a robot
body, a drive, a cleaning assembly, a pad holder, and a controller circuit. The robot
body defines a forward drive direction. The drive supports the robot body to maneuver
the robot across a floor surface. The cleaning assembly is disposed on the robot body
and includes a pad holder, a reservoir, and a sprayer. The pad holder has a bottom
surface configured to receive a cleaning pad and arranged to engage the floor surface,
and the bottom surface has one or more raised protrusions extending therefrom.
[0016] The reservoir is configured to hold a volume of fluid, and the sprayer, which is
in fluid communication with the reservoir, is configured to spray the fluid along
the forward drive direction forward of the pad holder. The controller circuit communicates
with both the drive system and the cleaning system and executes a cleaning routine.
The controller circuit executes a cleaning routine that allows the robot to drive
in the forward drive direction a first distance to a first location and then drive
in a reverse drive direction, opposite the forward drive direction, a second distance
to a second location. The cleaning routine allows the robot to spray fluid on the
floor surface from the second location, in the forward drive direction forward of
the pad holder but rearward of the first location. In this manner, the robot only
applies fluid to traversable floor and not to a wall, piece of furniture, carpet or
other non-floor area that triggers a bump sensor (collision) switch or proximity sensor
on the robot. After spraying fluid on the floor surface, the cleaning routine allows
the robot to drive in alternating forward and reverse drive directions while smearing
the cleaning pad along the floor surface.
[0017] In some implementations, the robot includes a toggle button for actuating the pad
holder release mechanism and ejecting the pad. In some implementations, the pad includes
a backing layer for engaging with the pad holder and the pad holder comprises raised
protrusions positioned for aligning to and engaging with shaped slots cut out of the
backing layer.
[0018] Another aspect of the disclosure provides a mobile floor cleaning robot that includes
a robot body, a drive, and a cleaning assembly. The robot body defines a forward drive
direction. The drive system supports the robot body to maneuver the robot across a
floor surface. The cleaning assembly is disposed on the robot body and includes a
pad holder and an orbital oscillator. The pad holder is disposed forward of the drive
wheels and has a top portion and a bottom portion. The bottom portion has a bottom
surface arranged within between about 0.5 cm and about 1.5 cm of the floor surface
and receives a cleaning pad. The bottom surface of the pad holder includes at least
40 percent of a surface area of a footprint of the robot and has one or more raised
protrusions extending therefrom. The orbital oscillator is disposed on the top portion
of the pad holder and has an orbital range less than 1cm. The pad holder is configured
to permit more than 80 percent of the orbital range of the orbital oscillator to be
transmitted from the top of the held cleaning pad to the bottom surface of the held
cleaning pad.
[0019] The one or more protrusions assist with aligning the pad to the pad holder and retaining
the pad securely in place during oscillation of the orbital oscillation while the
robot moves in a back and forth scrubbing cleaning pattern. In implementations, the
pad holder includes a release mechanism configured to eject the pad from the bottom
surface of the pad holder upon actuation of the release mechanism such that a user
need not touch a used, dirty pad to dispose of it. Actuating the release mechanism
while holding the robot above a trash container ejects the pad from the pad holder
into the trash container therebeneath.
[0020] In some examples, the robot moves in a birdsfoot motion forward and backward along
a center trajectory, forward and backward along a trajectory to the left of and heading
away from a starting point along the center trajectory, and forward and backward along
a trajectory to the right of and heading away from a starting point along the center
trajectory.
[0021] In some examples, the cleaning pad has a top surface attached to the bottom surface
of the pad holder and the top of the pad is substantially immobile relative to the
oscillating pad holder.
[0022] In some examples, the pad holder has a release mechanism configured to eject the
pad from the bottom surface of the pad holder upon actuation of a release mechanism.
In some examples, robot includes a toggle button for actuating the pad holder release
mechanism and ejecting the pad. In some examples, the pad includes a backing layer
for engaging with the pad holder and the pad holder comprises raised protrusions positioned
for aligning to and engaging with shaped slots cut out of the backing layer.
[0023] The cleaning assembly may further include at least one post disposed on the top portion
of the pad holder sized for receipt by a corresponding aperture defined by the robot
body. The at least one post may have a cross sectional diameter varying in size along
its length. Additionally or alternatively, the at least one post may include a vibration
dampening material.
[0024] In some implementations, the cleaning assembly further includes a reservoir to hold
a volume of fluid, and a sprayer in fluid communication with the reservoir. The sprayer
is configured to spray the fluid along the forward drive direction forward of the
pad holder. The reservoir may hold a fluid volume of about 200 milliliters.
[0025] The drive may include a drive body, which has forward and rearward portions, and
right and left motors disposed on the drive body. The right and left drive wheels
are coupled to the corresponding right and left motors. The drive may also include
an arm that extends from the forward portion of the drive body. The arm is pivotally
attachable to the robot body forward of the drive wheels to allow the drive wheels
to move vertically with respect to the floor surface. The rearward portion of the
drive body may define a slot sized to slidably receive a guide protrusion that extends
from the robot body. In one implementation, the cleaning pad disposed on the bottom
surface of the pad holder body absorbs about 90% of the fluid volume held in the reservoir.
The cleaning pad has a thickness of between about 6.5 millimeters and about 8.5 millimeters,
a width of between about 80 millimeters and about 68 millimeters, and a length of
between about 200 millimeters and about 212 millimeters.
[0026] In some examples, a method includes driving a first distance in a forward drive direction
defined by the robot to a first location, while moving a cleaning pad carried by the
robot along a floor surface supporting the robot. The cleaning pad has a center area
and lateral areas flanking the center area. The method further includes driving in
a reverse drive direction opposite the forward drive direction, a second distance
to a second location while moving the cleaning pad along the floor surface In this
manner, the robot only applies fluid to traversable floor and not to a wall, piece
of furniture, carpet or other non- floor area that triggers a bump sensor (collision)
switch or proximity sensor on the robot. The method also includes applying fluid to
an area on the floor surface substantially equal to a footprint area of the robot
and forward of the cleaning pad but rearward of the first location. The method further
includes returning the robot to the area of applied fluid in a movement pattern that
moves the center and lateral portions of the cleaning pad separately through the area
to moisten the cleaning pad with the applied fluid.
[0027] In some examples, the method includes driving in a left drive direction or a right
drive direction while driving in the alternating forward and reverse directions after
spraying fluid on the floor surface. Applying fluid on the floor surface may include
spraying fluid in multiple directions with respect to the forward drive direction.
In some examples, the second distance is at least equal to the length of a footprint
area of the robot.
[0028] In still yet another aspect of the disclosure, a method of operating a mobile floor
cleaning robot includes driving a first distance in a forward drive direction defined
by the robot to a first location while smearing a cleaning pad carried by the robot
along a floor surface supporting the robot. The method includes driving in a reverse
drive direction, opposite the forward drive direction, a second distance to a second
location while smearing the cleaning pad along the floor surface. The method also
includes spraying fluid on the floor surface in the forward drive direction forward
of the cleaning pad but rearward of the first location. The method also includes driving
in an alternating forward and reverse drive directions while smearing the cleaning
pad along the floor surface after spraying fluid on the floor surface.
[0029] In some implementations, the method includes spraying fluid on the floor surface
while driving in the reverse direction or after having driven in the reverse drive
direction the second distance. In implementations, the method includes driving in
a left drive direction or a right drive direction while driving in the alternating
forward and reverse directions after spraying fluid on the floor surface. Spraying
fluid on the floor surface may include spraying fluid in multiple directions with
respect to the forward drive direction. In some implementations, the second distance
is greater than or equal to the first distance.
[0030] The mobile floor cleaning robot may include a robot body, a drive, a pad holder,
a reservoir, and a sprayer. The robot body defines the forward drive direction and
has a bottom portion. The drive system supports the robot body and maneuvers the robot
over the floor surface. The pad holder is disposed on the bottom portion of the robot
body and holds the cleaning pad. The pad holder has a release mechanism configured
to eject the pad upon actuation, and the pad further comprising a backing layer for
engaging with the pad holder. The pad holder has a bottom surface having raised protrusions
extending therefrom and the raised protrusions are sized, shaped and positioned to
align to and engage with slots cut out of the backing layer.
[0031] The reservoir is housed by the robot body and holds a fluid (e.g., 200ml). The sprayer,
which is also housed by the robot body, is in fluid communication with the reservoir
and sprays the fluid in the forward drive direction forward of the cleaning pad. The
cleaning pad disposed on the bottom portion of the pad holder may absorb about 90%
of the fluid contained in the reservoir. In some examples, the cleaning pad has a
width of between about 80 millimeters and about 68 millimeters and a length of between
about 200 millimeters and about 212 millimeters. The cleaning pad may have a thickness
of between about 6.5 millimeters and about 8.5 millimeters. The details of one or
more implementations of the disclosure are set forth in the accompanying drawings
and the description below.
[0032] In some implementations, the fluid applicator is a sprayer that includes at least
two nozzles each distributing the fluid evenly across the floor surface in two strips
of applied fluid. The two nozzles are each configured to spray the fluid at an angle
and distance different than another nozzle. In some implementations, the two nozzles
are vertically stacked in a recess in the fluid applicator and angled from horizontal
and spaced apart from one another such that one nozzle sprays relatively longer lengths
of fluid forward and downward to cover an area in front of the robot with a forward
supply of applied fluid 173a, and the other nozzle sprays relatively shorter lengths
fluid forward and downward to leave a rearward supply of applied fluid on an area
in front of but closer to the robot than the area of applied fluid dispensed by the
top nozzle.
[0033] In implementations, the nozzle or nozzles dispense fluid in an area pattern that
extends one robot width and at least one robot length in dimension. In some implementations,
the top nozzle and bottom nozzle apply fluid in two distinct spaced apart strips of
applied fluid that do not extend to the full width of the robot such that the pad
passes through the outer edges of the strips of applied fluid in forward and backward
angled scrubbing motions as described herein. In embodiments, the strips of applied
fluid cover a width of 75-95% of the robot width and a combined length of the robot
length. In implementations, the strips of applied fluid may be substantially rectangular
shaped or ellipse shaped. In implementations, the nozzles complete each spray cycle
by sucking in a small volume of fluid at the opening of the nozzle so that no fluid
leaks from the nozzle following each instance of spraying.
[0034] In some implementations, the pad includes a cardboard backing layer adhered to the
top surface of the pad. The cardboard backing layer protrudes beyond the longitudinal
edges of the pad and the protruding longitudinal edges of the cardboard backing layer
attach to the pad holder of the robot. In one embodiment, the cardboard backing layer
is between 0.02 inch and 0.03 inch thick (0.05 cm and 0.762 cm thick), between 68
and 72 mm wide and between 90-94mm long. In one embodiment, the cardboard backing
layer 85 is approximately 0.066 cm (0.026 inch) thick, 70mm wide and 92mm long. In
one embodiment, the cardboard backing layer is coated on both sides with a water resistant
coating, such as wax or polymer or a combination of water resistant materials, such
as wax/polyvinyl alcohol/polyamine, and the cardboard backing layer does not disintegrate
when wetted.
[0035] In implementations, the pad is a disposable pad. In other examples, the pad is a
reusable microfiber cloth pad having the same absorptive characteristics as those
described herein with regard to embodiments. In examples having a washable, reusable
microfiber cloth, the top surface of the cloth includes a secured stiff backing layer
shaped and positioned like the cardboard backing layer described with regard to embodiments.
The stiff backing layer is made of heat resistant, washable material that withstands
being machine dried without melting or degrading the backing. The stiff backing layer
is dimensioned and has cutouts as described herein for interchangeable use with the
embodiment of the pad holder described with regard to embodiments herein.
[0036] In other examples, the pad is a disposable dry cloth and comprises a single layer
of needle punched spunbond or spunlace material having exposed fibers for entrapping
hair. The dry pad further comprises a chemical treatment that adds a tackiness characteristic
to the pad for retaining dirt and debris. In one embodiment, the chemical treatment
is a material such as that marketed under the trade name DRAKESOL.
[0037] In some examples, the pad is secured to an autonomous robot through a pad holder
attached to the robot. A pad release mechanism adjusts to an up or pad-secure position.
The pad release mechanism includes a retainer, or lip, that holds the pad securely
in place by grasping protruding longitudinal edges of a cardboard backing layer secured
to the top of the pad. In examples, the tip or end of the pad release mechanism includes
a moveable retention clip and an eject protrusion that slides up through a slot or
opening in the pad holder, and is pushed through the slot into a down position to
release the secured pad by pushing down on the attached cardboard backing layer.
[0038] Other aspects, features, and advantages will be apparent from the description and
drawings, and from the claims.
DESCRIPTION OF DRAWINGS
[0039]
FIG. 1A is an exploded view of an exemplary cleaning pad.
FIG. 1B is an exploded view of the wrap layer of the exemplary cleaning pad of FIG.
1.
FIG 1C is a section view of an exemplary cleaning pad.
FIG 1D is a section view of an exemplary cleaning pad where the airlaid layers include
superabsorbent polymers.
FIG. 2A is a schematic view of an exemplary arrangement of operations for a spunlace
process.
FIG. 2B is a perspective view of the hydroentaglement process for making the spunlace
layer used in the exemplary cleaning pad.
FIG. 3 is a perspective view of a device for making the abrasive meltblown layer used
in the exemplary cleaning pad.
FIG. 4 is a perspective view of an autonomous mobile robot for cleaning using the
exemplary cleaning pad.
FIG. 5 is a perspective view of a mop using the exemplary cleaning pad.
FIG. 6 is a bottom view of an exemplary cleaning pad.
FIG. 7 is a schematic view of an exemplary arrangement of operations for constructing
a cleaning pad.
FIG. 8A is a perspective view of an exemplary cleaning pad.
FIG. 8B is an exploded perspective view of the exemplary cleaning pad of FIG. 8A.
FIG. 8C is a top view of an exemplary cleaning pad.
FIG. 8D is a bottom view of an exemplary attachment mechanism for the pad as described
herein.
FIG. 8E is a side view of an exemplary attachment mechanism for a pad as described
herein in a secure position.
FIG. 8F is a top view of an exemplary attachment holder for the pad as described herein.
FIG. 8G is a cut away side view of an exemplary attachment mechanism for the pad as
described herein in a release position.
FIGS. 9A-9C are top views of an exemplary autonomous mobile robot as it sprays a floor
surface with a fluid.
FIG. 9D is a top view of an exemplary autonomous mobile robot as it scrubs a floor
surface.
FIG. 9E is a bottom view of an exemplary cleaning pad.
FIG. 9F is a top view of an exemplary autonomous mobile robot as it scrubs a floor
surface.
FIG. 9G is a top view of an exemplary autonomous mobile robot as it scrubs a floor
surface.
FIG. 10 is a schematic view of the robot controller of the exemplary autonomous mobile
robot of FIG. 4.
[0040] Like reference symbols in the various drawings indicate like elements.
DETAILED DESCRIPTION
[0041] Referring to FIGS. 1A, 1B and1C, in some implementations, a disposable cleaning pad
100 includes a plurality of absorbent airlaid layers 101, 102, 103 stacked, optionally
bonded to one another, and enwrapped by an outer non-woven layer 105 which can have
an abrasive meltblown elements 106 disposed thereon. In some examples, the cleaning
pad 100 includes one or more airlaid layers 101, 102, 103. As shown, the cleaning
pad 100 includes first, second and third airlaid layers 101, 102, 103, but additional
airlaid layers are possible as well. The number of airlaid layers 101, 102, 103 may
depend on the amount of cleaning fluid 172 the cleaning pad 100 is required to absorb.
Each airlaid layer 101, 102, 103 has a top surface 101a, 102a, 103a and a bottom surface
101b, 102b, 103b. The bottom surface 101b of the first (or top) airlaid layer 101
is disposed on the top surface 102a of the second airlaid layer 102, and the bottom
surface 102b of the second airlaid layer 102 is disposed on the top surface 103a of
the third (or bottom) airlaid layer 103. Fluid wicks between the three layers and
is retained uniformly vertically throughout the stack of airlaid layers without leaking
back onto a floor surface beneath the cleaning pad 100 while downward force is applied
to the pad 100. In implementations, the pad 100 retains 90 percent of fluid applied
to a floor surface 10 and under 1 pound of force, the pad 100 does not leak absorbed
fluid back onto the floor surface 10. The surface tension the top and bottom surfaces
of each airlaid layer helps retain wicked fluid within each layer such that as the
top layer 101 fully saturates, no fluid will leak down to the middle airlaid layer
102 through the bottom surface 101b of the top airlaid layer 101, and as the middle
airlaid layer 102 fully saturates, no fluid will leak down to the bottom layer through
the bottom surface 102b of the middle (or second) layer 102.
[0042] In implementations, the pad 100 soaks up 8-10 times its weight into a relatively
rigid matrix of airlaid layers 101, 102, 103, and fluid absorption is achieved through
capillary wicking, not by compress-release drawing because robot 400 to which the
pad is attached exerts very light, low variability cycle weight, not a cycle of heavy
human push down and draw back. Each of airlaid layer 101, 102, 103 slows down penetration
of wicked fluid to the next adjacent airlaid layer 101, 102, 103, such that early
cycles of fluid application do not lead to the pay quickly sopping up all the fluid
that is applied to the floor surface. The vertical stack of airlaid layers 101, 102,
103 provides a resistance to puddling at the bottom of the airlaid core comprising
the three airlaid layers 101, 102, 103. Each of the of airlaid layers 101, 102, 103
has its own puddle resisting bottom surface 101b, 102b, 103b for preventing puddling
of absorbed fluid all the way down at the bottom of the bottom surface 103b of the
bottom (or third) layer 103b.
[0043] In embodiments, the airlaid layers 101, 102, 103 are of non-uniform hardness or density
in the vertically direction such the outer top and bottom surfaces are harder than
the interior of each layer. In embodiments, the airlaid layers 101, 102, 103 are of
non-uniform surface density such that the outer top and bottom surfaces are smoother
and less absorptive than the interior of each layer. By varying the surface density
at the outer surfaces 101b, 102b, 103b of each of the airlaid layer 101, 102, 103,
the airlaid layers 101, 102, 103 remain absorptive, wicking fluid into each airlaid
layer without leaking back through the bottom surfaces 101b, 102b, 103b. By incorporating
three such airlaid layers 101, 102, 103 into the absorptive core of the pad 100, the
pad 100 therefore has superior fluid retention properties over a pad having a single
core of thickness equivalent to the three layer stacked core. The three airlaid layers
101, 102, 103 provide at least triple the amount of surface tension for retaining
wicked fluid in the absorptive cores of each of the airlaid layers 101, 102, 103.
[0044] A wrap layer 104 wraps around the airlaid layers 101, 102, 103 and prevents the airlaid
layers 101, 102, 103 from being exposed. The wrap layer 104 includes a wrap layer
105 (e.g., a spunlace layer) and an abrasive layer 106. The wrap layer 105 is wrapped
around the first, second, and third airlaid layers 101, 102, 103. The wrap layer 105
has a top surface 105a and a bottom surface 105b. The top surface 105b of the wrap
layer 105 covers the airlaid layers 101, 102, 103. The wrap layer 105 may be a flexible
material having natural or artificial fibers (e.g., spunlace or spunbond). The abrasive
layer 106 is disposed on the bottom side 105b of the wrap layer 105. Fluid applied
to a floor 10 beneath the cleaning pad 100 transfers through the wrap layer 105 and
into the airlaid layers 101, 102, 103. The wrap layer 105 wrapped around the airlaid
layers 101, 102, 103 is a transfer layer that prevents exposure of raw absorbent material
in the airlaid layers. If the wrap layer 105 were too absorbent, the pad 100 would
be suctioned onto a floor 10 and difficult to move. A robot, for example, may be unable
to overcome the suction force while trying to move the cleaning pad 100 across the
floor surface 10. Additionally, the wrap layer 105 picks up dirt and debris loosened
by the abrasion outer layer 106 and may leave a thin sheen of a cleaning fluid 172
on the surface 10 that air dries without leaving streak marks on the floor 10. The
thin sheen of cleaning solution is between 1.5 and 3.5 ml/square meter and dries in
a duration no longer than three minutes, and preferably dries within between about
2 minutes and 3 minutes.
[0045] The disposable cleaning pad 100 relies on capillary action (also known as wicking)
to absorb fluid on a floor surface 10. Capillary action occurs when a liquid is able
to flow in narrow spaces without external forces, such as gravity. Capillary action
allows a fluid to move within spaces of a porous material due to forces of adhesion,
cohesion, and surface tension. Adhesion of the fluid to the walls of a vessel will
cause an upward force on the liquid edges and result in meniscus, which turns upwards.
The surface tension acts to hold the surface intact. Capillary action occurs when
the adhesion to the walls is stronger than the cohesive forces between the fluid molecules.
[0046] In some examples, the airlaid layers 101, 102, 103 are a textile-like material made
from fluff pulp, which is a type of wood pulp/chemical pulp made from long fiber softwoods.
Chemical pulp is created by applying heat to a combination of wood chips and chemical
materials in a large container to break down the lignin (organic substance that binds
the cells in the wood). The textile-like material that is made from fluff pulp may
be very bulky, porous, soft, and has good water absorption properties. The textile-like
material does not scratch the floor surface, maintains its strength even when it is
wet, and may be washed and reused.
[0047] Referring to FIG. 1D, in some implementations, the airlaid layers 101, 102, 103 include
an absorbent layer of a mixture of air-laid paper and superabsorbent polymers 108
(e.g., sodium polyacrylate) for wetness. Polymers include plastic and rubber materials,
which are mainly organic compounds that are chemically based on carbon, hydrogen,
and other nonmetallic elements. Polymers generally have larger molecular structures,
which typically have low densities and may be extremely flexible. Superabsorbent polymers
108 (also known as slush powder) absorb and retain large amounts of a fluid in comparison
to their own mass. The ability of the superabsorbent polymers 108 to absorb water
depends on the ionic concentration of the aqueous solution. A superabsorbent polymer
108 may absorb up to 500 times its weight in deionized and distilled water (30-60
times its volume) and may become 99.9% liquid. The absorbency of the superabsorbent
polymers 108 drops significantly to about 50 times its weight when put into a 0.9%
saline solution. The valence cations in the saline solution prevent the superabsorbent
polymer 108 from bonding with the water molecules. The superabsorbent polymers 108
may expand causing the cleaning pad 100 to expand as well. Various implements 400,
500 may use the cleaning pad 100, and, in some examples, the implements 400, 500 may
not support a cleaning pad 100 that may expand. For example, expansion of the pad
100 may disturb the physics of a compact, lightweight robot 400, causing the compact
robot 400 to tilt upward and apply less force to the pad 100 for debris removal from
the floor 10. Therefore, less superabsorbent polymers 108 may be used to meet a cleaning
pad absorbency requirement. In one embodiment, the pad 100 may contain pockets in
a middle section along the pad length that allow superabsorbent polymers to expand
into those pockets and allow the pad to maintain a constant thickness as the superabsorbent
polymers expand.
[0048] In some implementations, the airlaid layers 101, 102, 103 include a cellulose pulp
nonwoven material that is through air bonded with a bicomponent fiber. In some examples,
fibers of wood pulp cellulose are thermally bonded with bicomponent polyethylene,
and/or polypropylene, which has a low melting point. This mixture forms a solid absorbent
core that holds its formed shape and that evenly distributes absorbed fluid, preventing
cleaning fluid from pooling at the lowest point in the layer and preventing additional
fluid accumulation. The airlaid layers 101, 102, 103 may be manufactured from a bleached
wood pulp that looks like a thick layer of cardboard. The pulp enters a hammer mill
having blades on a rotor that strikes the thick layer of pulp and devibrates it into
individual fibers. The individual fibers enter a distributor having a screen rotor
that looks like a flour sifter. The fibers are formed into a sheet on another screen
having an applied vacuum underneath, at which stage the sheet is blended with a sheet
of bicomponent fiber. Blown hot air melts the bicomponent to bond with the airlaid.
[0049] The airlaid layers are situated so as to distribute the absorbed liquid substantially
uniformly throughout the core, without puddling of liquid anywhere in the core layers
(expand?). The mobile robot 400 sprays fluid 172 in front of the robot uniformly and
the pad 100 picks up the applied solution 173a, 173b in an even distribution along
its length when traveling forward. In one embodiment, the airlayed layers 101, 102,
103 are bonded with spray adhesive applied evenly over the surface of the airlaid
layer 101, 102, 103. In one embodiment, the adhesive is polyolefin and is applied
in a thin, uniform manner to get reliable adhesion without creating ridges and stiff
areas. The spray adhesive also creates a uniformly bonded surface interface, allows
fluid to wick into the airlaid layers 101, 102, 103 without a large mechanical barrier
(for example, stitches, or relatively large impermeable glue patches or ridges) and
this uniformly bonded surface interface between airlaid layers 101, 102, 103 prevents
puddling between the layers 101, 102, 103.
[0050] A very small amount of acrylic latex bonding agent may be sprayed sparingly on both
the surfaces to bind the external layers and to minimize sloughing and help reduce
linting. Linting is a condition that occurs when fine ravelings of cotton, linen,
or fiber are apparent on an object or fabric. The airlaid layers 101, 102, 103 may
include 15% of biocomponent polymers, 85 % cellulose, and latex at the top to eliminate
linting.
[0051] The wrap layer 105 may be of any material that is thin and absorbs fluid. In addition,
the wrap layer 105 may be smooth to prevent scratching the floor surface 10. In some
implementations, the cleaning pad 100 may include one or more of the following cleaning
agent constituents butoxypropanol, alkyl polyglycoside, dialkyl dimethyl ammonium
chloride, polyoxyethylene castor oil, linear alkylbenzene sulfonate, glycolic acid
- which for example serve as surfactants, and to attack scale and mineral deposits,
among other things; and including scent, antibacterial or antifungal preservatives.
[0052] In some examples, the wrap layer 105 is a spunlace nonwoven material. Spunlace may
also be known as hydroentangling, water entangling, jet entangling or hydraulic needling.
Spunlace is a process of entangling a web of loose fibers typically formed by a card
on a porous belt or moving perforated or patterned screen to form a sheet structure
by subjecting the fibers to multiple passes of fine high-pressure water jets. The
hydroentangling process enables formation of specialty fabrics by adding fibrous materials,
such as tissue paper, airlaid, spunlace and spunbond nonwovens to composite non-woven
webs. These materials offer performance advantages needed for many wipe applications
due to their improved performance or cost structure.
[0053] Referring to FIGS. 2A and 2B, the spunlace process 200 includes a precursor web forming
process 202a. The precursor web is usually made of staple textile-like fibers. These
webs can be single fiber webs or made of many different fiber blends. The typical
four fibers of choice are polyester, viscose, polypropylene and cotton. Variants of
each of these fibers may also be used, such as organic cotton, as well as Lyocell
material, and Tencel rayon. PLA (polylactic acid) fibers which are biodegradable can
also be used.
[0054] The precursor web forming process 202a may include forming airlaid cards, which may
be used to provide a more isotropic web as a result of higher transversal orientation
of the fibers. Carding is a method of making thin webs of parallelized fibers. Higher
bulk may also be obtained by using this type of carding system. Once the web of staple
fibers is formed, a second layer of fibers may be placed on top of this base by air
forming cellulose fibers, or by "laminating" a preformed nonwoven web, such as tissue,
spunlace or spunbond. In some examples, spunbond isisnonwoven material is combined
is combined with airlaid layers and thus the resulting fabric eliminates the carding
step of hydroentangling continuous fibers with cellulose pulp fibers. This fibrous
composition then goes under a fiber entangling process 204 constituted of rows of
high-pressure water jets 210 that duplicate the conventional mechanical needling process
and intertwine the fibers individually, so that they become entangled forming a web
212.
[0055] The spunlace process 200 includes applying a fiber entangling process 204 to the
fibrous composition. The fiber entangling process 204 includes jetting water from
rows of high-pressure water jets 210 to duplicate the conventional mechanical needling
process and intertwine the fibers individually so that they become entangled, forming
a web 212. The web 212 (after going through the web forming and carding process 202)
is placed on a conveyor belt 214 rotated by two or more pulleys 216. During and/or
after each water injection process the web 212 goes through drums with suction 218
that suck the water out of the fiber and allow the fiber to keep moving to the next
high-pressure water jets 210.
[0056] The consolidated nonwoven substrate 215 is subsequently dried through air-dryers
in an air dryer process 206 and then wound in a winding process 208.
[0057] The wrap layer 105 can be printed on as well as thermally embossed. Embossing and
debosing are processes for creating raised or recessed designs in fabric or other
material. A relatively lower melt fiber, such as polypropylene, may be used to achieve
better thermal embossing. The coefficient of friction of the wrap layer 105 varies
based on surface type and wetness. In on embodiment, a dry pad 100 moving on glass
has a coefficient of friction of about 0.4 to about 0.5, and wet on tiles has a coefficient
of friction of about 0.25 to about 0.4. The wrap layer 105 may include hydroembossing,
which imparts three dimensional images on the fabric. Hydroembossing is generally
less expensive than thermal bonding. In one example, the wrap layer 105 is embossed
with a herringbone pattern. The wrap layer 105 wrapped around a series of airlaid
layers 101, 102, 103 enables the formation of an absorbent core that locks in absorbed
fluid. The layering of airlaid core layers 101, 102, 103 enables capillary action
and retention throughout the combined core and within each individual layer 101,102,
103. Furthermore, the airlaid layers 101, 102, 103 making up the core of the pad retain
their shape while distributing fluid evenly throughout each fluid retention layer
and preventing pooling that would prohibit additional absorption.
[0058] The abrasion meltblown layer 106 includes meltblown fibers 107, which are fibers
formed by extruding a molten thermoplastic material through a plurality of fine, usually
circular, die capillaries as molten threads or filaments into converging high velocity
gas streams that cut the filaments of molten thermoplastic material to reduce their
diameters. Thus, the meltblown fibers 107 are carried by the high velocity gas stream
and placed on a surface that collects the fibers, therefore forming a web of randomly
distributed meltblown fibers 107.
[0059] In some examples, the abrasion meltblown layer 106 is a layer of meltblown fibers
107 that provide a rough surface. The meltblown fibers 107 are formed by a meltblown
process 300 (see FIG. 3) at high throughput, which creates spittle, or hair like fibers,
that are formed by a polymer drooled from the die orifices due to temperature and
other conditions in which it is run. The abrasive layer 106 is formed on top of the
wrap layer 105 (e.g., another meltblown layer, a spunbond layer, or a spunlace layer).
The wrap layer 105 may be a herring bone hydroembossed nonwoven material, which is
made of a ratio of viscose (rayon) fibers blended with polyester fibers. In some examples,
the abrasion meltblown layer 106 has a basis weight (also known as grammage) equal
to 55g/m
2 (grams per square meter). The wrap layer 105 may have a basis weight of between about
30 gsm (grams per square meter) and about 65 gsm. In other examples, the wrap layer
may have a basis weight of between about 35-40 gsm. Basis weight is a measurement
used in both the fabric and paper industries to measure the mass of the product per
unit of area. In an embodiment, the wrap layer 105 is a hydroentangled spunbond or
spunlace material formed with indentations (not show) therein that allow fluid and
suspended dirt to pass more directly through to the airlaid layers 101, 102, 103 and
reduce the amount of cohesive suction between the wrap layer 105 and the floor surface
10 when the pad 100 is wet. In one embodiment, the indentations are in a herringbone
pattern. In another embodiment, the indentations form a grid of squares sized and
spaced to be between 0.50 and 1.0 mm square and spaced apart in a grid formation by
a length of 2.0-2.5 mm. In one embodiment, the indentations are sized and spaced to
be 0.75mm square and spaced apart in a grid formation by a length of 2.25mm. In another
embodiment, the wrap layer 105 is a spunbond or spunlace material having needle-punched
holes therein for improving the wicking ability of the wrap layer 105 and decreasing
the cohesion between the wet wrap layer 105 and the floor surface 10. The herringbone,
square and needle punched indentations prevent a negative pressure from generating
at the outside of the wrap layer as fluid evaporates and/or wicks from the back of
the liner. Without free movement inside the wrap layer 105 or some texture on the
wrap layer 105, fluid applied to the floor surface 10 cannot replace the wicked fluid,
and that causes suction between the pad 100 and the floor. Combining a low density
spunbond or spunlace material of 35-40 gsm with a surface texture in the form of hydroembossed
indentations, surface textures and patterns (such as herringbone), or needle punched
indentations or holes prevents suction between the pad and the floor. The meltblown
layer 105 further assists with preventing this this suction force.
[0060] Additionally, when a pad 100 is damp, not enough fluid is present to lubricate the
interface between the bottom surface of the pad and the floor surface 10. A fully
wetted pad 100 will ride on a layer of fluid while the robot 400 is moving, but as
the damp pad 100 slowly absorbs fluid, the not fully wet, not fully lubricated, wrap
layer 106 will drag on the floor surface 10. In implementations, the spunbond or spunlace
wrap layer 105 is manufactured with hydrophilic fibers that minimize the surface area
of the pad 100 exposed to air between the pad 100 and the floor surface 10. A wet
pad 100 would stick to the hydrophilic floor surface 10 if the indentations or needle
punches were not part of the wrap layer 100. Applying a surface texture to the spunbond
or spunlace of the wrap layer 105 breaks the surface tension that would otherwise
case a wet pad 100 to stick to a wet floor surface 10.
[0061] The weight of the abrasion meltblown layer 106 is such that the abrasion meltblown
layer 106 acts as an absorbing layer and allows for fluid to be absorbed through the
meltblown layer 106 and be retained by the airlaid layer 101, 102, 103. In some examples,
the meltblown layer 106 covers about 60 to about 70% of the surface area of the spunlace
wrap layer 105 and in other examples, the meltblown layer 106 covers about 50-60%
of the surface area of a spunbond or spunlace wrap layer 105.
[0062] The meltblown fibers 107 may have different arrangements and configurations on the
spunlace wrap layer 105. In some examples, the meltblown fibers 107 are randomly arranged
on the wrap layer 105. The meltblown fibers 107 may be arranged in one or more sections
109a-e on a cleaning surface 109. The cleaning surface 109 is a bottom surface of
the cleaning pad 100 that is in contact with the floor surface 10. The one or more
sections 109a-e on the cleaning surface 109 have a covered ratio between the meltblown
abrasive fibers 107 and the wrap layer 105 greater than 50%. The meltblown layer provides
the pad with the advantages of breaking surface tension that might otherwise cause
the wet wrap layer to stick to a wet floor. By adding texture and topography to a
floor facing surface of the pad, the meltblown layer prevents the pad from sticking
or encountering high drag forces. The meltblown layer also provides the pad with surface
texture for roughing up dirt and debris stuck or dried to a floor surface and loosening
dirt and debris for absorption by the airlaid inner core of the pad.
[0063] As shown in FIG. 3, the meltblown process 300 is a process that extrudes and draws
molten polymer resins with a heated, high velocity air 310 to form fibers or filaments
107. The fibers/filaments 107 are cooled and are then formed into a web 106 on top
of a moving screen 320. This process 300 is similar to spunbond, but the fibers 107
generated here are much finer and range in the 0.1 to 20 µm (e.g., 0.1 - 5 µm) diameter
range. Meltblowing is also considered a spunmelt or spunlaid process. The process
shown in FIG. 3 shows an extrusion die 312 (beam) that extrudes the melt blown polypropylene
fibers into a continuous porous conveyor to form the nonwoven web 106. It is made
up of six major components: the extruder, metering pump, extrusion die, web forming,
web consolidation and winding. Other processes are possible as well.
[0064] There are two basic die designs 312 used with the meltblown technology, the single
row die and the multi-row die. The key difference between these two designs is the
amount of air that is used as well as the throughput of the die. With the multi-row
die, much greater throughput may be achieved. Multi-row dies usually have two to eighteen
rows of holes and approximately three hundred holes per inch, while the conventional
single row dies have twenty-five to thirty-five holes per inch. Either die design
312 may be used to form the meltblown fibers 107. Throughput for this process is much
less than the 200+ kg/hr/meter (kilograms per hour per meter) obtained for spunbond
or spunlace with its much larger fiber diameters. Conventional dies basically can
extrude 70 to 90 kg/hr/meter, while the multi-row die can achieve about 160kg/hr/meter.
[0065] In some implementations, the meltblown fibers 107 have a diameter of between about
0.1 µm and about 5 µm with a mean of about 2.5 µm. Throughput and air flows have the
greatest impact at reducing the fiber diameter, with melt and air temperatures and
distance of the die from the forming table have less of an impact. Optimizing the
process variables and using metallocene polypropylene may yield meltblown webs with
mean fiber diameters in the range of 0.3 to 0.5 µm with maximum fiber diameters of
less than 3µm. A wrap layer 104 with meltblown fibers 107 of this size can provide
a barrier against fluid leakage from the cleaning pad 100 by providing very high hydrohead
webs with excellent breathability. The meltblown fibers 107 may be created using homopolymer
polypropylene; however, several other resins can be extruded by the meltblown process
as well, such as polyethylene, polyester, polyamides and polyvinyl alcohols. In some
implementations, the meltblown layer 106 is formed from polylactic acids (PLA), a
biodegradable nonwoven.
[0066] In some examples, the airlaid layers 101, 102, 103, the abrasion layer 104 and the
wrap layer 104 (i.e., the cleaning pad 100) have a combined width W
T of between about 68 millimeters and about 80 millimeters and a combined length (not
shown) of between about 200 millimeters and about 212 millimeters. In some examples,
the cleaning pad 100 including the airlaid layers 101, 102, 103, the abrasion layer
104 and the wrap layer 105 have a combined thickness T
T of between 6.5 millimeters and about 8.5 millimeters. Additionally, or alternatively,
the airlaid layers 101, 102, 103 have a combined airlaid width (W
A1 + W
A2 + W
A3) of between 69 millimeters and about 75 millimeters and a combined airlaid length
(L
A1 + L
A2 + L
A3) of between about 165 millimeters and about 171 millimeters. The cleaning pad 100
withstands pressure being applied to it by an implement 400, 500 (e.g., robot or mop),
since an implement 400, 500 will cause back and forth movement of the cleaning pad
100 mimicking a scrubbing action as the robot 400 traverses the floor surface 10.
[0067] In some implementations, as the cleaning pad 100 is cleaning a floor surface 10,
it absorbs cleaning fluids 172 applied to the floor surface 10. The cleaning pad 100
may absorb enough fluid without changing its shape. Therefore, where the cleaning
pad 100 is used along with a cleaning robot 400, the cleaning pad 100 has substantially
similar dimensions before cleaning the floor surface 10 and after cleaning the floor
surface 10. The cleaning pad 100 may increase in volume when it absorbs fluids. In
some examples, the thickness of the cleaning pad T
T increases by less than 30% after fluid absorption.
[0068] In some implementations, the wrap layer 104 has the specifications listed in Table
1 below:
Table 1
| Wrap Layer |
| Characteristic |
Unit |
Average Value |
Tolerance |
Test Method |
| Weight |
g/m2 |
55 |
+/- 10% |
ASTM D3776M-09A |
| Thickness |
mm |
0.6 |
0.55-0.65 |
WSP 120.6 |
| Tensile Strength (DRY) |
N/2.54cm (MD) |
50 |
> 40 |
ASTM D5034-09 |
| N/2.54cm (CD) |
25 |
> 20 |
| Elongation at break (DRY) |
% (MD) |
45 |
25-65 |
ASTM D5034-09 |
| % (CD) |
90 |
65 - 115 |
| Water absorption |
% |
600 |
> 500 |
WSP 10.0 (05) |
| Abrasion resistance |
Visual at 80 cycles |
OK |
No visible degradation |
- |
| Meltblown Abrasive |
| Covered surface ratio |
% |
50 |
44 - 57 |
- |
| Scrubbing fiber average size |
µm |
N/A |
8µm - 20µm |
- |
[0069] ASTM D3776M-09A and ASTM D5034-09 are standardized tests from the American Society
for Testing and Materials (ASTM). ASTM D3776M-09A covers the measurement of fabric
mass per unit area (weight) and is applicable to most fabrics. ASTM D5034-09, also
known as the Grab test, is a standard test method for breaking strength and elongation
of textile fabrics. WSP 120.6 and WSP 10.0 (05) are standardized tests created by
World Strategic Partners for testing the properties of nonwoven fabrics.
[0070] Referring to FIGS. 1A-1D , 3, 4-6 and 9A-9C, the cleaning pad 100 is configured to
scrub a floor surface 10 and absorb fluids on the floor surface 10. In some examples,
the cleaning pad 100 is attached to a cleaning implement such as a mobile robot 400
or a handheld mop 500. The cleaning implement 400, 500 may include a sprayer 462,
512 that sprays a cleaning fluid 172 on the floor surface 10. The implement 400, 500
is used to scrub and remove any smears (e.g., dirt, oil, food, sauces, coffee, coffee
grounds) that are being absorbed by the pad 100 along with the applied fluid 172 that
dissovles and/or loosens the smears 22. Some of the smears may have viscoelastic properties,
which exhibit both viscous and elastic characteristic (e.g., honey). The cleaning
pad 100 is absorbent and has an outer surface 105a that includes a randomly applied
abrasive layer 106 comprising meltblown fibers 107. As the implement 400, 500 moves
about the floor surface 10, the cleaning pad 100 wipes the floor surface 10 with the
abrasive side 105b containing the abrasive layer 106b of meltblown fibers and absorbs
cleaning solution sprayed onto the floor surface 10 with only a light amount of force
than otherwise required by scrubbing mops having a non-abrasive cleaning element.
[0071] Referring to FIG. 4, in some implementations, the implement 400 is a compact, lightweight
autonomous mobile robot 400 that weighs less than 5lbs and navigates and cleans a
floor surface 10. The mobile robot 400 may include a body 410 supported by a drive
system (not shown) that can maneuver the robot 400 across the floor surface 10 based
on a drive command having x, y, and θ components, for example. As shown, the robot
body 410 has a square shape. However, the body 410 may have other shapes, including
but not limited to a circular shape, an oval shape, a tear drop shape, a rectangular
shape, a combination of a square or rectangular front and a circular back, or a longitudinally
asymmetrical combination of any of these shapes. The robot body 410 has a forward
portion 412 and a rearward portion 414. The body 410 also includes a bottom portion
(not shown) and a top portion 418. The bottom portion of the robot body 410 further
comprises one or more rear cliff sensors (not shown) in one or both of the two rear
corners of the robot 400 and one or more forward cliff sensors located in one or both
of the front corners of the mobile robot 400 for preventing falls from ledged surfaces.
In embodiments, the cliff sensors may be mechanical drop sensors or light based proximity
sensors, such as an IR (infrared) pair, a dual emitter, single receiver or dual receiver,
single emitter IR light based proximity sensor aimed downward at a floor surface 10.
In some examples, the one or more forward cliff sensors and one or more rear cliff
sensors are placed at an angle relative to the forward and rear corners, respectively,
such that they cut the corners, spanning between sidewalls of the robot 400 and covering
the corner as closely as possible to detect flooring height changes beyond a threshold
accommodated by reversible robot wheel drop prior. Placing the cliff sensors proximate
the corners of the robot 400 ensures that they will trigger immediately when the robot
400 overhangs a flooring drop and prevent the robot wheels from advancing over the
drop edge.
[0072] In some implementations, the forward portion 412 of the body 410 carries a movable
bumper 430 for detecting collisions in longitudinal (A,F) or lateral (L,R) directions.
The bumper 430 has a shape complementing the robot body 410 and extends forward the
robot body 410 making the overall dimension of the forward portion 412 wider than
the rearward portion 414 of the robot body 410 (the robot as shown has a square shape).
The bottom portion of the robot body 410 supports the cleaning pad 100. In embodiments,
the pad 100 extends beyond the width of the bumper 430 such that the robot 400 can
position an outer edge of the pad 100 up to and along a tough to reach surface or
into a crevice, such a wall floor interface, and such that the surface or crevice
is cleaned by the extended edge of the pad 100 the while the robot 400 moves in a
wall following motion. The embodiment of a pad 100 extending beyond the width of the
bumper 430 enables the robot 400 to clean in cracks and crevices beyond the reach
of the robot body 410. In embodiments, such as those shown in FIGS. 1A-1D and FIGS.
8A-8C and 9E, the pad 100 has bluntly cut ends 100d such that the airlaid layers 101,
102, 103 are exposed at both ends 100d of the pad 100. Instead of the wrap layer 105
being sealed at the ends 100d of the pad 100 and compressing the ends 1.00d of the
airlaid layers 101, 102, 103, the full length of the pad 100 is available for fluid
absorption and cleaning. No portion of the airlaid core is compressed by the wrap
layer 105 and therefore unable to absorb fluid 172. Additionally, a used disposable
pad 100 of this embodiment will not have soaking wet, floppy ends of sealed wrap layer
105 at the completion of a cleaning run. All fluid 172 will be securely absorbed and
held by the airlaid core, preventing any drips and preventing a user from undesirably
contacting dirty wet ends of the pad 100.
[0073] As shown in FIGS. 4 and 9A-9G, the robot 400 may drive back and forth to cover a
specific portion of the floor surface 10. As the robot 400 drives back and forth,
it cleans the area it is traversing and therefore provides a deep scrub to the floor
surface 10. A reservoir 475 housed by the robot body 410 holds a cleaning fluid 172
(i.e. cleaning solution) and may hold 170-230 mL of fluid. In embodiments, the reservoir
475 holds 200mL of fluid. The robot 400 may include a fluid applicator 462 connected
to the reservoir 475 by a tube. The fluid applicator 462 may be a sprayer having at
least one nozzle 464 that distributes fluid over the floor surface 10. The fluid applicator
462 may have multiple nozzles 464 each configured to spray the fluid at an angle and
distance different than another nozzle 464. In some examples, the robot 400 includes
two nozzles 464, vertically stacked in a recess in the fluid applicator 462 and angled
and spaced such that one nozzle 464a sprays relatively longer lengths of fluid 172a
forward and downward to cover an area in front of the robot 400 with a a forward supply
of applied fluid 173a and the other nozzle 464b sprays relatively shorter lengths
fluid 172b forward and downward to leave a rearward supply of applied fluid 173b on
an area in front of but closer to the robot 400 than the area of applied fluid 173a
dispensed by the top nozzle 464a. In embodiments, the nozzle 464 or nozzles 464a,
464b dispense fluid 172, 172a, 172b in an area pattern that extends one robot width
W
R and at least one robot length L
R in dimension. In some embodiments, the top nozzle 464a and bottom nozzle 464b apply
fluid 172a, 172b in two distinct spaced apart strips of applied fluid 173a, 173b that
do not extend to the full width W
R of the robot 400 such that the pad 100 passes through the outer edges of the strips
of applied fluid 173a, 173b in forward and backward angled scrubbing motions as described
herein. In embodiments, the strips of applied fluid 173a, 173b cover a width W
S of 75-95% of the robot width W
R and a combined length L
S of 75-95% of the robot length L
R. In some implementations, the robot 400 only sprays on traversed areas of the floor
surface 10.
[0074] Moreover, the back and forth movement of the robot 400 breaks down stains on the
surface floor 10. The broken down stains are then absorbed by the cleaning pad 100.
In some examples, the cleaning pad 100 picks up enough of the sprayed fluid to avoid
uneven streaks if the cleaning pad 100 picks up too much liquid, e.g fluid 172. In
case of too little fluid absorption, the robot 400 might leave fluid and wheel traces.
In some embodiments, the cleaning pad 100 leaves a residue of the fluid, which could
be water or some other cleaning agent including solutions containing cleansing agents,
to provide a visible sheen on the surface floor 10 being scrubbed. In some examples,
the fluid contains antibacterial solution, e.g., an alcohol containing solution. A
thin layer of residue, therefore, is purposely not absorbed by the cleaning pad 100
to allow the fluid to kill a higher percentage of genus. Therefore, the cleaning pad
100 does not swell or expand and provides a minimal increase in total pad thickness
T
T. This characteristic of the cleaning pad 100 prevents the robot 400 from tilting
backwards or pitching up if the cleaning pad 100 expands. The cleaning pad 100 is
sufficiently rigid to support the front of the robot. In some examples, the cleaning
pad 100 absorbs up to 180 ml or 90% of the total fluid contained in the robot reservoir
475. In some examples, the cleaning pad holds about 55 to about 60 ml of fluid and
a fully saturated wrap layer holds about 6 to about 8 ml of fluid 172. In some examples
the ratio of fluid retention in the airlaid core 101,102,103 to the outer wrap layer
105 is about 9:1 to about 5:1.
[0075] The pad 100 and robot 400 are sized and shaped such that the transfer of fluid from
the reservoir to the absorptive pad 100 maintains the forward and aft balance of the
less than 5lb robot 400 during dynamic motion. The fluid distribution is designed
so that the robot 400 continually propels the pad 100 over a floor surface 10 without
the interference of the increasingly saturated pad 100 and decreasingly occupied fluid
reservoir 475 lifting the back 414 of the robot 400 and pitching the front 412 of
the robot 400 downward and thereby applying movement-prohibitive downward force to
the robot 400. The robot 400 is able to move the pad 100 across the floor surface
10 even when the pad 100 is fully saturated with fluid. The robot 400 however includes
the feature of tracking the amount of floor surface 10 travelled and/or the amount
of fluid remaining in the reservoir 475 and provides an audible and/or visible alert
to a user that the pad 100 requires replacement and/or the reservoir 475 requires
refilling. In embodiments, the robot 400 stops moving and remains in place on the
floor surface if the pad 100 is fully saturated, and there remains floor to be cleaned
once the pad 100 is replaced.
[0076] FIGS. 9A through 9G detail the spraying, pad wetting, and scrubbing motions of one
embodiment of the mobile robot 400. In some implementations, the robot 400 only applies
fluid 172 to areas of the floor surface 10 that the robot 100 has already traversed.
In one example, the fluid applicator 462 has multiple nozzles 464a, 464b each configured
to spray the fluid 172a, 172b in a direction different than another nozzle 464a, 164b.
The fluid applicator 462 may apply fluid 172 downward rather than outward, dripping
or spraying fluid 172 directly in front of the robot 100. In some examples, the fluid
applicator 462 is a microfiber cloth or strip, a fluid dispersion brush, or a sprayer.
[0077] Referring to FIGS. 9A-9D and 9F-9G, in some implementations, the robot 400 may execute
a cleaning behavior by moving in a forward direction F toward an obstacle 20, followed
by moving in a backward or reverse direction A. As indicated in FIGS. 9A and 9B, the
robot 400 may drive in a forward drive direction a first distance Fd to a first location
L1. As the robot 400 moves backwards a second distance Ad to a second location L2,
the nozzles 464a, 464b simultaneously spray longer lengths fluid 172a and shorter
lengths of fluid 172b onto the floor surface 10 in a forward and/or downward direction
in front of the robot 400 after the robot 400 has moved at least a distance D across
an area of the floor surface 10 that was already traversed in the forward drive direction
F. In one example, the fluid 172 is applied to an area substantially equal to or less
than the area footprint AF of the robot 400. Because distance D is the distance spanning
at least the length L
R of the robot 400, the robot 400 determines that the area of floor 10 traverses is
clear floor surface 10 unoccupied by furniture, walls 20, cliffs, carpets or other
surfaces or obstacles onto which cleaning fluid 172 would be applied if the robot
100 had not already verified the presence of a clear floor surface 10 for receiving
cleaning fluid 172. By moving in a forward direction F and then backing up prior to
applying cleaning fluid 172, the robot 400 identifies boundaries, such as a flooring
changes and walls, and prevents fluid damage to those items.
[0078] As shown in FIGS. 4, 9B and 9C, in some examples, the fluid applicator 462 is a sprayer
462 that includes at least two nozzles 464a, 464b, each distributing the fluid 172
evenly across the floor surface 10 in two strips of applied fluid 173a, 173b. The
two nozzles 464a, 464b are each configured to spray the fluid at an angle and distance
different than another nozzle 464a, 464b. In some examples, the two nozzles 464a,
464b are vertically stacked in a recess in the fluid applicator 462 and angled from
horizontal and spaced apart from one another such that one nozzle 464a sprays relatively
longer lengths of fluid 172a forward and downward to cover an area in front of the
robot 400 with a forward supply of applied fluid 173a, and the other nozzle 464b sprays
relatively shorter lengths fluid 172b forward and downward to leave a rearward supply
of applied fluid 173b on an area in front of but closer to the robot 400 than the
area of applied fluid 173a dispensed by the top nozzle 464a. In embodiments, the nozzle
464 or nozzles 464a, 464b dispense fluid 172, 172a, 172b in an area pattern that extends
one robot width W
R and at least one robot length L
R in dimension. In some embodiments, the top nozzle 464a and bottom nozzle 464b apply
fluid 172a, 172b in two distinct spaced apart strips of applied fluid 173a, 173b that
do not extend to the full width W
R of the robot 400 such that the pad 100 passes through the outer edges of the strips
of applied fluid 173a, 173b in forward and backward angled scrubbing motions as described
herein. In embodiments, the strips of applied fluid 173a, 173b cover a width Ws of
75-95% of the robot width W
R and a combined length L
S of 75-95% of the robot length L
R. In embodiments, the strips of applied fluid 173a, 173b may be substantially rectangular
shaped or ellipse shaped. In embodiments, the nozzles 464a, 464b complete each spray
cycle by sucking in a small volume of fluid at the opening of the nozzle so that no
fluid 172 leaks from the nozzle following each instance of spraying.
[0079] Referring to FIGS. 9D, 9F and 9G, in some examples, the robot 400 may drive back
and forth to cover a specific portion of the floor surface 10, wetting the cleaning
pad 100 at the start of a cleaning run and/or scrubbing the floor surface 10. The
robot 400 drives back and forth, cleaning the area traverse and therefore providing
a thorough scrub to the floor surface 10. The robot 400 oscillates the attached pad
100 in an orbit of 12-15mm to scrub the floor 10 and applies approximately 0.4536
kg (1 pound) of downward pushing force or less to the pad.
[0080] In some examples, the fluid applicator 462 applies fluid 172 to an area in front
of the cleaning pad 100 and in the direction of travel (e.g., forward direction F)
of the mobile robot 100. In some examples, the fluid 172 is applied to an area the
cleaning pad 100 has previously occupied. In some examples, the area the cleaning
pad 100 has occupied is recorded on a stored map that is accessible to a robot controller
150, as shown in the diagram of FIG. 10. The robot 400 may include a cleaning system
1060 for cleaning or treating a floor surface 10.
[0081] In some examples, the robot 400 knows where it has been based on storing its coverage
locations on a map stored on the non-transitory- memory 1054 of the robot 400 or on
an external storage medium accessible by the robot 400 through wired or wireless means
during a cleaning run. The robot 400 sensors 5010 may include a camera and/or one
or more ranging lasers for building a map of a space. In some examples, the robot
controller 1050 uses the map of walls, furniture, flooring changes and other obstacles
10 to position and pose the robot 400 at locations far enough away from obstacles
and/or flooring changes prior to the application of cleaning fluid 172. This has the
advantage of applying fluid 172 to areas of floor surface 10 having no known obstacles
thereon.
[0082] In some examples, the robot 100 moves in a back and forth motion to moisten the cleaning
pad 100 and/or scrub the floor surface 10 to which fluid 172 has been applied. The
robot 400 may move in a birdsfoot pattern through the footprint area AF on the floor
surface 10 to which fluid 172 has been applied. As depicted, in some implementations,
the birdsfoot cleaning routine involves moving the robot 100 in forward direction
F and a backward or reverse direction A along a center trajectory 1000 and in forward
direction F and a backward direction A along left 1010 and right 1005 trajectories.
In some examples, the left trajectory 1010 and the right trajectory 1005 are arcuate
trajectories that extend outward in an arc from a starting point along the center
trajectory 1000. The left trajectory 1010 and the right trajectory 1005 may be straight
line trajectories that extend outward in a straight line from the center trajectory
1000.
[0083] FIGS. 9D and 9F depict two birdsfoot trajectories. In the example of FIG. 9D, the
robot 400 moves in a forward direction F from Position A along the center trajectory
1000 until it encounters a wall 20 and triggers a sensor 5010, such as a bump sensor,
at Position B. The robot 400 then moves in a backward direction A along the center
trajectory to a distance equal to or greater than the distance to be covered by fluid
application. For example, the robot 400 moves backward along the center trajectory
1000 by at least one robot length 1 to Position G, which may be the same position
as Position A. The robot 400 applies fluid 172 to an area substantially equal to or
less than the footprint area AF of the robot 100 and returns to the wall 20, the cleaning
pad 400 passing through the fluid 172 and cleaning the floor surface 10. From position
B, the robot 100 retracts either along a left trajectory 1010 or a right trajectory
1005 before returning to Position B and covering the remaining trajectory. Each time
the robot 400 moves forward and backward along the center trajectory 1000, left trajectory
1010 and right trajectory 1005, the cleaning pad 100 passes through the applied fluid
172, scrubbing dirt, debris and other particulate matter from the floor surface 10
to which the fluid 172 is applied and absorbing the dirty fluid into the cleaning
pad 100 and away from the floor surface 10. The scrubbing motion of the moistened
pad combined with the solvent characteristics of the cleaning fluid 172 breaks down
and loosens dried stains and dirt. The cleaning fluid 172 applied by the robot 400
suspends loosened debris such that the cleaning pad 100 absorbs the suspended debris
and wicks it away from the floor surface 10.
[0084] In the example of FIG. 9F, the robot 400 similarly moves from a starting position,
Position A, through applied fluid 172, along a center trajectory 1000 to a wall position,
Position B. The robot 400 backs off of the wall 20 along the center trajectory 1000
to Position C, which may be the same position as Position A, before covering left
and right trajectories 1010, 1005, extending to positions D and F, with the cleaning
fluid 172 distributed along the trajectories 1010, 1005 by the cleaning pad 100. In
one example, each time the robot 400 extends along a trajectory outward from the center
trajectory 1000, the robot 400 returns to a position along the center trajectory as
indicated by Positions A, C, E and G, as depicted in FIG. 9F. In some implementations,
the robot 400 may vary the sequence of backward direction A movements and forward
direction F movements along one or more distinct trajectories to move the cleaning
pad 100 and cleaning fluid 172 in an effective and efficient coverage pattern across
the floor surface.
[0085] In some examples, the robot 100 may move in a birdsfoot coverage pattern to moisten
all portions of the cleaning pad 100 upon starting a cleaning run. As depicted in
FIG. 9E, the bottom surface 100b of the cleaning pad 100 has a center area PC and
right and left lateral edge areas PR and PL. When the robot 100 starts a cleaning
run, or cleaning routine, the cleaning pad 100 is dry and needs to be moistened to
reduce friction and also to spread cleaning fluid 172 along the floor surface 10 to
scrub debris therefrom.
[0086] The robot 400 therefore applies fluid at a higher volumetric flow rate initially
at the start of a cleaning run such that the cleaning pad 100 is readily moistened.
In one implementation, the first volumetric flow rate is set by spraying about 1mL
of fluid every 45,72 cm (1.5 feet) initially for a period of time such as l-3minutes,
and the second volumetric flow rate is set by spraying every 91,44 cm (3 feet), wherein
each spray of fluid is less than 1mL of volume. In embodiments, the robot 400 applies
fluid 172 every 30,48 cm or 60,96 cm (one to two feet) at the start of a run to saturate
the wrap layer 105 of the pad 100 early in the cleaning run. After a period of time
and/or distance, such as a duration of 2-10 minutes, the robot 400 applies fluid at
intervals of every 91,44 cm to 152.4 cm (three to five feet) because the pad 100 is
moistened and able to scrub the floor 10. As FIG. 9G depicts, in some examples, at
the start of a cleaning run, the robot 400 drives the cleaning pad 100 through applied
fluid 172 such that the center area PC of the bottom surface 100b of the cleaning
pad 100 and the left and right lateral edge areas PR and PL of the cleaning pad 100
each pass through the applied fluid 172 separately, thereby moistening the entire
cleaning pad 100 along the entire bottom surface 100b of the cleaning pad 100 in contact
with the floor surface 10.
[0087] In the example of FIG. 9G, the robot 400 moves in a forward direction F and 10 then
backward direction A along a center trajectory 1000, passing the center of the pad
100 through the applied fluid 172. The robot 400 then drives in a forward direction
F and backward direction A along a right trajectory 1005, passing the left lateral
area PL of the cleaning pad 100 through the applied fluid 172. The robot 100 then
drives in a forward direction F and backward direction A along a left trajectory 1010,
passing the right lateral area PR of the cleaning pad 100 through the applied fluid
172. At the start of the cleaning run, the robot applies fluid 172 at a relatively
high initial volumetric flow rate Vi and/or high initial frequency of application,
applying a larger quantity of fluid 172 more frequently to the surface 10 and/or applying
a fixed amount of fluid 172 more frequently to the surface 10 to moisten the cleaning
pad 100 quickly. Moistening the cleaning pad reduces friction and also enables the
pad 100 to dissolve more debris 22 without requiring more frequent applications of
fluid 172. In embodiments, the coefficient of friction of the warp layer 105 of the
pad 100 varies from 0.3 to 0.5 depending on material of the floor 10 and wetness of
the pad 100. In one embodiment, a dry pad 100 moving on glass has a coefficient of
friction of around 0.4 to 0.5, and wet on tiles has a coefficient of friction of about
0.25 to 0.4.
[0088] Once the wrap layer 105 of the cleaning pad 100 is moistened, the robot 400 continues
its cleaning run and subsequently applies fluid 172 at a second volumetric flow rate
Vf. This second volumetric flow rate Vf is relatively lower than the initial flow
rate Vi at the start of the cleaning run because the cleaning pad 100 is already moistened
and effectively moves cleaning fluid across the surface 10 as it scrubs. In one implementation,
the initial volumetric flow rate Vi is set by spraying about 1mL of fluid every 30.48
cm (1.5 feet) initially for a period of time such as l-3minutes, and the second volumetric
flow rate Vf is set by spraying every 91.44 cm (3 feet), wherein each spray of fluid
is less than 1mL of volume. The robot 400 adjusts the volumetric flow rate V such
that a cleaning pad 100 of specified dimensions is moistened on the bottom surface
100b (FIG. 9E) without being fully wetted to capacity internally in the airlaid layers
101, 102, 103. The bottom surface 100b of the cleaning pad 100 is initially moistened
without the absorbent interior of the pad 100 being water logged such that the cleaning
pad 100 remains fully absorbent for the remainder of the cleaning run. The back and
forth movement of the robot 400 breaks down stains 22 on the floor surface 10. The
broken down stains 22 are then absorbed by the cleaning pad 100.
[0089] In some examples, the cleaning pad 100 picks up enough of the sprayed fluid 172 to
avoid uneven streaks. In some examples, the cleaning pad 100 leaves a residue of the
solution to provide a visible sheen to the floor surface 10 being scrubbed. In some
examples, the fluid 172 contains antibacterial solution; therefore, a thin layer of
residue is purposely not absorbed by the cleaning pad 100 to allow the fluid 172 to
kill a higher percentage of germs.
[0090] In an embodiment, the pad may be scented. The scent agent may be integrated into
or applied onto one or more of the airlaid core layers, the liner or a combination
of the airlaid layers and liner. The scenting agent may be inert in a pre- activation
stage and activated by fluid to release scent so that the pad only produces a scent
during use and otherwise produces no scent while stored. In another embodiment, the
pad includes a cleaning agent or surfactant that may be integrated into or applied
onto one or more of the airlaid core layers, the liner, or a combination of the airlaid
layers and liner. In one embodiment, the cleaning agent is applied to only the back
surface (unexposed, non-meltblown side) of the liner in contact with the lower most
airlaid core member such that the cleaning agent is released through the porous liner,
onto the cleaning surface when in contact with fluid. The cleaning agent may be a
foaming agent and/or a cleaning agent with a visibly glossy sheen indicating the application
of the cleaning agent the cleaning surface. In another embodiment, the pad includes
one or more chemical preservatives applied to or manufactured within the cardboard
backing element. The preservatives are selected to prevent the growth
of wood spores that may be present in the wood based backing element. Some embodiments
of the pad may include all of these features - conventional scent agent, cleaning
agent, antibacterial agent and preservatives - or combinations of fewer than all of
these features, including, for example, an encapsulated scent..
[0091] Referring to FIG. 5, in some examples, the implement 500 is a mop 500. The mop 500
includes a body 502 supporting a reservoir 504 that holds a cleaning fluid 172 (e.g.
a cleaning solution). A handle 506 is disposed on one side of the body 502. The handle
includes a controller 508 for controlling the release of the fluid from the reservoir
504. A movable rotatable base 510 is disposed on the other end of the body 502 opposite
the handle 506. The base 510 includes a fluid applicator 512 connected to the reservoir
504 by a tube (not shown). The fluid applicator 512 may be a sprayer having at least
one nozzle 514 that distributes fluid over the floor surface 10. The nozzle 514 sprays
forward and downwards of the base 510 towards the floor surface 10. A user controlling
the controller 508 sprays the fluid 172 when needed. The fluid applicator 512 may
have multiple nozzles 514 each configured to spray the fluid in a direction different
than another nozzle 514.
[0092] Referring to FIGS. 6, and 8E-8G, a retainer 600, 600a, 600b may be disposed on the
implement 400, 500 supporting the cleaning pad 100. The retainer 600, 600a, 600b is
disposed on a bottom portion of the implement 400, 500 for retaining the cleaning
pad 100. In one embodiment, the retainer 600 may include hook-and-loop fasteners,
and in another embodiment, the retainer 600 may include clips, or retention brackets,
and selectively moveable clips or retention brackets for selectively releasing the
pad for removal. Other types of retainers may be used to connect the cleaning pad
100 to implement 400, 500, such as snaps, clamps, brackets, adhesive, etc., which
may be configured to allow the release of the cleaning pad 100 upon activation of
a pad release mechanism located on the implement 400, 500 such that user need not
touch the dirty used pad to remove the pad from the cleaning implement 400, 500.
[0093] FIG. 7 provides an exemplary arrangement of operations for a method 700 of constructing
a cleaning pad 100. The method 700 includes disposing 710 a first airlaid layer 101
on a second airlaid layer 102 and disposing 720 the second airlaid layer 102 on a
third airlaid layer 103. The method 700 further includes wrapping 730 a wrap layer
104 around the first, second, and third airlaid layers 101, 102, 103. The wrap layer
104 includes a spunlace wrap layer 105, and a meltblown abrasive 107 adhered to the
spunlace wrap layer 105.
[0094] In some examples, the method 700 further includes adhering and randomly arranging
meltblown abrasive 107 on the spunlace wrap layer 105. Additionally or alternatively,
the meltblown abrasive fibers may have a diameter of between about 0.1 µm and about
20 µm. The method 700 may further include arranging the meltblown abrasive and the
spunlace wrap layer 105 to have a collective thickness of between 0.5 mm and about
0.7 mm on the spunlace wrap layer 105. In some examples, the melblown abrasive 107
creates a thickness gap of 0.5mm between the wrap layer 105 and the floor 10. Because
of this thickness gap, the pad 100 can pick up a 1.5mm diameter bubble of fluid sitting
on the floor 10 with surface tension without requiring force. The lowest points of
the embossed cover 105 layer are only 0.5 mm from the floor 10 and the remainder of
the surface area of wrap layer 105 is 3mm from the floor 10.
[0095] The method 700 may further include arranging the meltblown abrasive 107 on the spunlace
wrap layer 105 to provide a covered surface ratio between the meltblown abrasive 107
and the spunlace wrap layer 105 of between about 60% and about 70%. In some examples,
the method 700 may include adhering the first airlaid layer 101 to the second airlaid
layer 102 and adhering the second airlaid layer 102 to the third airlaid layer 103.
The airlaid layers 101, 102, 103 may be of a cellulose based textile material (e.g.,
a material including fluff pulp).
[0096] In some implementations, the method 700 may include where the first, second, and
third airlaid layers 101, 102, 103, the spunlace wrap layer 105, and the meltblown
abrasive are configured to increase in thickness by less than 30% after fluid absorption.
The method 700 may further include embossing the spunlace layer105. The method 700
may also include disposing sodium polyacrylate in one or more of the airlaid layers
101, 102, 103.
[0097] In some examples, the method 700 further includes configuring the airlaid layers
101, 102, 103 and wrap layer 104 to have a combined width of between about 80 millimeters
and about 68 millimeters, and a combined length of between about 200 millimeters and
about 212 millimeters. The method 700 may further include configuring the airlaid
layers 101, 102, 103 and the wrap layer 104 to have a combined thickness of between
about 6.5 millimeters and about 8.5 millimeters. The method 700 may include configuring
the airlaid layers 101, 102, 103 to have a combined airlaid width of between 69 millimeters
and about 75 millimeters, and a combined airlaid length of between about 165 millimeters
and about 171 millimeters.
[0098] FIGS.8E-G demonstrate an exemplary release mechanism for the pad 100 as described
herein. FIGS. 8A-8C show an embodiment of the pad 100 having a core of three airlaid
layers 101, 102, 103 bonded and enclosed in a wrap layer 105 adhered to the top surface
of the top airlaid layer 101. Additionally, the embodiment of FIGS. 8A-8C include
a cardboard backing layer 85 adhered to the top surface of the pad 100. The cardboard
backing layer 85 protrudes beyond the longitudinal edges of the pad 100 and the protruding
longitudinal edges 86 of the cardboard backing layer 85 attach to the pad holder 82
of the robot 100. In one embodiment, the cardboard backing layer 85 is between 0.02"
and 0.03" thick, between 68 and 72 mm wide and between 90-94mm long. In one embodiment,
the cardboard backing layer 85 is .026" thick, 70mm wide and 92mm long. In one embodiment,
the cardboard backing layer 85 is coated on both sides with a water resistant coating,
such as wax or polymer or a combination of water resistant materials, such as wax/polyvinyl
alcohol, polyamine, and the cardboard backing layer 85 does not disintegrate when
wetted.
[0099] In embodiments, the bottom surface 100b of the pad 100 may include one or more hair
catching strips 100c for catch and collect loose hair during cleaning. In the embodiment
of FIG. 9E, two hair catching strips 100c are depicted in dashed line to indicate
the option nature of this feature. In an embodiment having one or more hair catching
strips 100c, the strip or strips 100c may be located on outer longitudinal edges of
the pad 100 or in a single strip on either longitudinal edge of the pad or down the
middle of the pad. In embodiments, each hair catching strip 100c is less than 30%
of the total surface area of the bottom surface 100b of the pad 100 and preferably
is less than 20% of the surface area of the bottom surface 100b of the pad 100. The
hair catching strip 100c may be a strip of material added to the wrap layer 105 that
includes loose fibers with catching features, such as Velcro
® hooks, rough edged fibers or fibers with a fused tip.
[0100] As shown in FIGS.8E and 8G, the pad 100 as described herein can be secured to an
autonomous robot through a pad holder 82 which can be attached to the robot 400. An
exemplary pad release mechanism 83 is also shown in an up or pad-secure position.
The pad release mechanism 83 includes a retainer 600a, or lip, that holds the pad
100 securely in place by grasping the protruding longitudinal edges 86 of the cardboard
backing layer 85. In the version shown, the tip or end 84 of the pad release mechanism
83 includes a moveable retention clip 600a and an eject protrusion 84 that slides
up through a slot or opening in the pad holder 82 when the pad is inserted into the
holder 82, and is pushed into a down position to release the secured pad 100 as shown
in FIG 8G, as shown here pushing down on the attached backing layer 85, e.g. cardboard
backing. The relationship between the pad and the pad holder 82 is also shown in a
top view in FIG 8F. In one embodiment, the pad release mechanism 83 is activated by
a toggle button 477 located under the handle 419 of the robot 400, as shown in FIG.
4. The toggle motion is indicated by the dotted double arrow 478. Toggling the toggle
button 477 moves a spring actuator that rotates the pad release mechanism 83, moving
the retention clip 600a away from the cardboard backing layer 85 and moving the eject
protrusion 84 through the slot in the the pad holder 882 so that the eject protrusion
pushes the pad 100 out of the holder.
[0101] Returning to FIGS. 8A and 8B, in embodiments, the cardboard backing layer 85 may
include cutouts 88 centered along the protruding longitudinal edges 86 of the cardboard
backing layer 85 and corresponding in position with raised protrusion 94 on the bottom
of the pad holder 82, as shown in FIG. 8D. In another embodiment, the cardboard backing
layer 85 contains a first set of cutouts 88 centered on the protruding longitudinal
edges 86 of the cardboard backing layer 85 and a second set of cutouts 90 on the lateral
edges of the cardboard backing layer 85. The cutouts 88, 90 are symmetrically centered
along the longitudinal center axis PCA
lon of the pad 100 and lateral center axis PCA
lat of the pad 100 and engage with corresponding protrusions 92, 94 centered on the longitudinal
center axis HCA
lon of the underside of the pad holder 82 and lateral center axis PCA
lat on the underside of the pad holder 82. The pad holder 82 of the embodiment of FIG.
8D includes three raised protrusions 92, 94. This is so that a user may install the
pad 100 in either of two identical directions (180 degrees opposite to one another)
while allowing the pad holder 82 to more easily release the pad 100 when the release
mechanism 83 is triggered. Other embodiments of the pad holder include four protrusions
92, 94 corresponding in position to the four cutouts 88, 90 on the cardboard backing
layer in FIG. 8C. In still other embodiments, the pad holder 82 and pad 100 respectively
include raised protrusions and corresponding cut outs in any other number or configuration
for holding the pad in place and enabling selective release.
[0102] In FIG. 8D, the raised protrusion 94 on the longitudinal edge of the pad holder 82
is obscured by the retaining bracket 600a, which is shown in phantom view so that
the raised protrusion 94 therebeneath is visible in the exemplary view. The protrusions
92, 94 both poke yoke attachment of the disposable pad 100 to the bottom of the pad
holder 82 so that alignment if the pad 100 to the holder 82 is precise and retain
the pad 100 relatively stationary to the pad holder 82 by preventing lateral and/or
transverse slippage.
[0103] Because the cutouts 88, 90 extend into the surface area of the cardboard backing
layer 85, they respectively interface with more lateral and longitudinal surface area
of the raised protrusions 92, 94 and the pad is held in place against rotational forces
as well by the cutout-protrusion retention system. The robot 100 moves in a scrubbing
motion, as described above, and, in embodiments, the pad holder 82 oscillates the
pad for additional scrubbing. In embodiments, the robot 400 oscillates the attached
pad 100 in an orbit of 12-15mm to scrub the floor 10 and applies approximately 0.4536
kg (1 pound) of downward pushing force or less to the pad. By aligning cutouts 88,
90 in the cardboard backing layer 85 with protrusions 92, 94, the pad 100 remains
stationary relative to the holder during use, and the application of scrubbing motion,
including oscillation motion, directly transfers from the pad holder 82 through the
layers of the pad without loss of transferred movement.
[0104] In embodiments, the pad of FIGS. 1A-1D and 8A-8C are disposable pads. In other embodiments,
the pad 100 is a reusable microfiber cloth pad having the same absorptive characteristics
as those described herein with regard to embodiments. In embodiments having a washable,
reusable microfiber cloth, the top surface of the cloth includes a secured stiff backing
layer shaped and positioned like the cardboard backing layer of the embodiments of
FIGS. 8A-8C. The stiff backing layer is made of heat resistant, washable material
that can be machine dried without melting or degrading the backing. The stiff backing
layer is dimensioned and has cutouts as described herein for interchangeable use with
the embodiment of the pad holder 82 described with regard to the embodiments of FIGS.
8A-8G.
[0105] In other examples, the pad 100 is intended for use as a disposable dry cloth and
comprises a single layer of needle punched spunbond or spunlace material having exposed
fibers for entrapping hair. The dry pad 100 embodiment further comprises a chemical
treatment that adds a tackiness characteristic to the pad 100 for retaining dirt and
debris. In one embodiment, the chemical treatment is a material such as that marketed
under the trade name DRAKESOL.