Note: Descriptions are shown in the official language in which they were submitted.
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CLEANING DEVICE WITH ROTATING BRUSHES
FIELD OF THE INVENTION
The invention relates to a cleaning device for cleaning a surface, the
cleaning
device comprises at least one brush rotatable in a rotation direction and
movable over the
surface to be cleaned and at least one deflector contacting the bristles of
the brush at a
location, seen in the rotation direction, before the location where the
bristles contact the
surface to be cleaned.
The invention also relates to a vacuum cleaner.
BACKGROUND OF THE INVENTION
By such a device which is known from WO 2005/053498 a rotatable brush is
being used to aid in the loosening and removal of dirt and foreign material
from the surface
to be cleaned. To perform the cleaning action the brush is pressed against the
surface. To
improve the cleaning of the surface, a cleaning liquid is being used. The
cleaning liquid is
removed from the surface by means of the rotating brush, together with the
dirt. Droplets of
the cleaning liquid on the inside of the housing of the brush are guided back
to the brush by
means of the deflector. To ensure that no droplets will fall back on the
cleaned surface, the
deflector must be pressed firmly against the brush. This has the disadvantage
that the power
needed to rotate the brush is increased and brush wear will be more. However,
if the deflector
is not sufficiently pressed against the brush, droplets will fall back to the
surface, which will
negatively effects the cleaning result.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a cleaning device whereby the
contact between the brush and the deflector is being improved.
This object is achieved by the cleaning device according to the invention in
that the deflector is movable against spring force.
Both the deflector and the bristles of the brush will be moved when getting in
contact with each other when the brush is being rotated. If the brush is worn
or deformed, the
deflector is will still keep in touch with the brush, although in this
situation the deflector will
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be moved less. In case that the diameter of the brush is larger than expected,
for example due
to production tolerances, the deflector will be moved more.
By the movable deflector an optimal balance between a sufficient contact with
the brush to prevent droplets on the cleaned surface and minimum power
dissipation by the
motor due to the contact between the brush and the deflector can be obtained.
In case that the cleaning device is being used for cleaning a surface with
liquid
whereby the water or cleaning liquid must be removed from the surface, the
deflector can be
used for preventing droplets of water or cleaning liquid from falling back on
the cleaned
surface.
However, the cleaning device is also suitable for cleaning without cleaning
liquid. The bristles are pressed together by the deflector, whereby air will
be pushed out of
the area between the bristles. Between the deflector and the surface to be
cleaned, the bristles
will be moved apart and the area between the bristles will increase so that
air will be sucked
into the brush. Because the air is sucked into the brush close to the position
where the brush
is pressed together by the surface to be cleaned, the blowing of air caused by
the surface to be
cleaned is compensated for. Also in this case, an optimal balance between a
sufficient contact
with the brush to create suction and a minimum power dissipation by the motor
due to the
contact between the brush and the deflector can be obtained.
The deflector itself can be relatively stiff and be mounted by means of
springs
to the housing of the brush or the deflector can be flexible and be moved with
respect to the
brush by being bent.
Another embodiment of the cleaning device according to the invention is
characterized in that the deflector comprises at least one flexible plate-
shaped element being
bendable against spring force of the plate-shaped element.
Such a deflector is relatively cheap and can easily be mounted to the housing.
The plate-shaped element can be made of a plastic like silicon rubber, a
polymer or any other
suitable material like natural rubber.
A further embodiment of the cleaning device according to the invention is
characterized in that the stiffness of the deflector is less than 200*10-
3N/mm, preferably
20*10-3N/mm and more preferably 2*10-3N/mm per millimetre length of the brush.
With such a stiffness it is possible that the deflector extends relatively far
into
the brush, for example 2 mm or more, when the brush is not rotated so that a
good contact
between the deflector and brush during rotation is ensured, whereby nearly no
wear of the
brush due to the contact with the deflector will occur and the power
dissipation of the motor
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due to this contact will be relatively low. Preferably the deflector is very
elastic, and has a
stiffness of less than 2*10-3N/mm per millimetre length of the brush. At a
brush with a length
of 250 mm, the total stifthess is 2*10-3N/mm * 250 mm is 0,5 N/mm. The
stifthess of the
deflector can be determined, for example, by exerting a bending force, i.e. a
force having the
effect that the deflector is subjected to a bending deformation, on the end of
the deflector
extending in normal use into the brush until the end has moved 1 mm.
Another embodiment of the cleaning device according to the invention is
characterized in that the bristles are bent by the deflector to an extend that
suction between
the bristles when losing contact with the deflector is larger than expellation
of air from
between the bristles when contacting the surface to be cleaned.
With such bending of the bristles by the deflector a net air flow towards to
the
brush will occur near the surface.
The axle of the brush is kept at a certain predetermined distance from the
surface, for example by means of wheels connected to a housing of the cleaning
device.
Another embodiment of the cleaning device according to the invention is
characterized in that the bending of the bristles by the deflector is larger
than the bending of
the bristles by the surface to be cleaned.
Also in this situation the net air flow by the brush will be directed towards
the
brush.
A further embodiment of the cleaning device according to the invention is
characterized in that the cleaning device comprises at least two brushes
rotatable in opposite
directions directed towards each other at the surface to be cleaned, whereby
at least two
deflectors are provided pressing against the bristles of the brushes, each
deflector is located
on a side of a brush remote from the other brush.
Due to the two brushes rotating in opposite direction a very effective
cleaning
operation is obtained since each location on the surface to be cleaned will be
contacted by
both brushes. Furthermore the dirt will be collected between the brushes and
can easily be
moved in an upwards direction to a debris collecting chamber.
A further embodiment of the cleaning device is characterized in that the
deflector is adjustable with respect to the brush. In this manner the pressure
between the
deflector and the brush can be varied. Moreover one can compensate for
possible wear of the
bristles.
To prevent dripping from water near ends of the brush, an embodiment of the
cleaning device according to the invention is characterized in that the
cleaning device is
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provided with at least one side deflector pressing against the bristles of the
brush located near
an end of the brush.
Water inside the housing of the cleaning device will fall either on the
deflector
or on the side deflector and will be guided back into the brush. No stripes or
droplets will
occur on the cleaned surface. If droplets on the surface will occur, this will
be an indication
that the brushes have been worn and should be replaced by new fresh brushes.
According to one aspect of the present invention, there is provided cleaning
device for cleaning a surface, the cleaning device comprises at least one
brush rotatable in a
rotation direction and movable over the surface to be cleaned and at least one
deflector
contacting the bristles of the brush at a location, seen in the rotation
direction, before the
location where the bristles contact the surface to be cleaned, wherein the
deflector is movable
against spring force when the bristles of the brush are getting in contact
with the deflector
when the brush is being rotated.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be explained in more detail with reference to the drawings,
in which
Fig. 1 is a side view of a rotatable brush according to the prior art,
Fig. 2 is a perspective view of a cleaning device according to the invention,
Fig. 3 is a schematic side view of a part of the cleaning device as shown in
Fig. 2,
Figs. 4A and 4B are respectively a schematic side view of a brush with a
deflector according to the invention and a graph indicating the volume between
the bristles of
the brush while rotating the brush,
Figs. 5A and 5B are a schematic side view and bottom view of the cleaning
device according to the invention,
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Figs. 6-8 are bottom views of the several other embodiments of the deflectors
according to the invention,
= Figs. 9-11 are perspective views of other embodiments of the deflector
according to the invention.
Like parts are indicated by the same reference numbers in the figures.
DETAILED DESCRIPTION OF EMBODIMENTS
= Fig. 1 is a side view of a rotatable brush according to the prior art. As
is
schematically illustrated, air will be expelled from the rotating brush in the
direction indicated
by arrow P1 when contact is made at position A with the surface to be cleaned.
The air will
be expelled from the brush from the position A to position B. From position B,
air will be
sucked in a direction indicated by arrow P2 into the brush to compensate for
the increasing
volume between the bristles, until the bristles have lost contact with the
surface (position C).
The airflow in the direction indicated by arrow P2 towards the brush aids the
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cleaning action of the brush. However the airflow in the direction indicated
by arrow P1
away from the brush is detrimental to the cleaning action since dirt will be
blown away.
Fig. 2 shows a perspective view of a cleaning device 1 according to the
invention, comprising a housing 2 in which two brushes 3, 4 are rotatably
mounted around
5 axles 5, 6. The brushes 3, 4 are driven by a motor (not shown). The motor
might be located
on any suitable position whereby via gears of belts the brushes 3, 4 are being
rotated with a
speed of 5000-10,000 rotations per minute. The axle of the motor can also be
directly
connected to the axle of the brush, whereby the motor can be placed inside the
brush, for
example. The diameter of the brushes for example is 4 cm a 6 cm. The length of
the brush is
for example about 25 cm. Brush 3 is rotatable in a clockwise direction,
indicated by arrow P3
and brush 4 is rotatable in a counter clockwise direction, indicated by arrow
P4 around the
respective axles 5, 6. The housing 2 is provided with wheels (not shown)
keeping the axles 5,
6 at a predetermined distance of the surface to be cleaned. The housing 2 is
connected via a
steering joint to a stick 7 which is provided on a side remote of the housing
2 with a handle 8.
The cleaning device 1 is furthermore provided with a tank 9 for water or other
cleaning
liquid. A power cord 10 enters the handle 8 and is guided through the stick 7
to the motor for
rotating the brushes 3, 4 and the device (not shown) for feeding water from
the container 9
into a brush from which it is spread on to the surface to be cleaned.
The housing 2 comprises a debris collecting chamber 11, the entrance 12 of
which is located between the brushes 3, 4. The brushes 3, 4 are fully enclosed
except at the
bottom by the housing 2. For sake of clarity the side cover has been removed.
Near the
bottom of the housing 2 two longitudinal flexible deflectors 13, 14 are
provided extending
parallel to the axles 5, 6 and partly into the brushes 3, 4. The function of
the deflectors 13, 14
will now be explained with reference to the drawings 3, 4A and 4B.
As can be seen in fig. 3 the brushes 3, 4 rotate in opposite directions P3,
P4,
which directions are directed towards each other near the surface to be
cleaned 16. The
bristles 17 of the brushes 3, 4 rub over the surface to be cleaned 16 and the
dirt and other
materials are being disconnected from the surface to be cleaned 16 and are
being moved
upwards in the direction of arrow P5 into the entrance 12 of the debris
collecting chamber 11.
When the bristles 17 of the brushes 3, 4 reach the deflectors 13, 14 the
bristles 17 are pressed
together whereby the volume between the bristles is being reduced. Hereby air
is being
expelled from the brushes 3, 4, which air is guided along the walls 18 of the
housing 2. By
further rotating of the brushes 3, 4 the bristles 17 lose contact with the
deflectors 13, 14
whereby the area between the bristles is being enlarged and air will be sucked
into the
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brushes 3, 4. By further rotating the bristles 17 will be pressed against the
surface to be
cleaned 16 whereby air will be expelled from the area between the bristles
3,4. The net air
flow between the deflectors 13, 14 and the surface to be cleaned 16 is in the
directions
indicated by the arrows P6, P7 towards the brushes 3, 4 respectively. Such a
net air intake by
the brushes 3, 4 will for example occur if the bending of the brushes 3, 4 by
the deflectors 13,
14 is greater than the bending of the brushes 3, 4 by the surface to be
cleaned 16. The
bending by the deflectors 13, 14 of the brushes 3, 4 is for example 5 mm while
the surface to
be cleaned 16 bends the brushes 3, 4 for example only 3 mm. The deflectors
press against the
bristles of the brush at a location before the location where the bristles
contact the surface to
be cleaned as seen in the direction of rotation.
Fig. 4A shows brush 3 and different angles cp whereby the bristles come in
contact with the deflector 13 (near cp = a), lose contact with the deflector
13 (c) = b), start with
losing contact with the surface to be cleaned 16 (c) = c) and have fully lost
contact with the
surface to be cleaned 16 (c) = d). When moving from cp = b to cp = d the
volume between the
bristles is at its minimum at cp = c.
Fig. 4B shows a graph whereby the volume between the bristles 17 is
indicated at different angles cp. As is clearly visible in the graph the
volume between the
bristles 17 is being reduced between the angles cp = a and cp = b whereby air
is blowing in the
direction indicated by arrow P8 along the walls 18 of the housing 2. Between
the angles cp = b
and cp = c air is being sucked towards the brush 3 in the direction indicated
by arrow P6. Also
between the angles cp = c and cp = d air is being sucked towards the brush 3
however now in
the direction indicated by arrow P7.
The cleaning device 1 according to the invention can be used for cleaning soft
surfaces with carpet and hard surfaces. It can be used by only rotating the
brushes 3, 4 but the
cleaning can be supported by sucking vacuum by means of vacuum device in the
entrance 12.
Furthermore the device 1 can be used for wet cleaning of for example hard
surfaces whereby
water or a cleaning liquid is guided from the container 9 towards the brushes
3, 4 and the
surface 16 is being wetted by the brushes 3, 4. It is also possible to spray
water on the surface
by means of a separate device in which case the cleaning device need not to be
provided with
a container 9. It is important that as little as possible water or cleaning
liquid remains on the
surface 16. The water or cleaning liquid will be removed by the brushes 3, 4
and guided into
the entrance 12 towards the debris collecting chamber 11. As can be seen in
fig. 5A some of
the water droplets 19 will be collected against the wall 18 of the housing 2
and will flow back
along the wall 18 and over the deflectors 13, 14 into the brushes 3, 4. Hereby
the water
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droplets 19 are prevented from being dropped back on the surface to be cleaned
16. Also
water on the outside of the housing 2 will be guided back to the brushes 3, 4
due to the shape
of the housing, whereby the ends of the deflectors 13, 14 located in the
brushes 3,4, form the
lowest part of the housing.
The deflectors 13, 14 form part of a bottom plate 21 as indicated in Fig. 5B.
The bottom plate 21 can be made from flexible plastic being easily bendable.
To prevent
water droplets 19 to fall back on the surface 16 near ends 20 of the
cylindrical brushes 3, 4
the bottom plate 21 comprises side edges 22, whereby the distance between
opposite side-
edges 22 is shorter than the length of the brush 3,4. Water droplets 19 will
either be guided
by the side edges 22 of the bottom plate 21 towards a V-shaped nose 23 from
which the
droplets 19 will fall between the brushes 3, 4 and will be picked up by the
brushes 3, 4 during
a next passage of the brushes 3, 4 or the droplets will be picked up by the
brushes when
moving towards the V-shaped nose 23. The V-shaped nose 23 can also be another
kind of
protruding element.
Fig. 6 shows a bottom view of another embodiment of the cleaning device 31
according to the invention whereby each deflector 13, 14 is connected to a
carrier 32, 33
respectively. The carriers 32, 33 are connected to each other at their side
edges by means of
adjusting mechanisms 34. Each adjusting mechanism 34 comprises a rod 35 and an
adjusting
knob 36 whereby by rotating the adjusting knob 36 in or opposite to a
direction indicated by
arrows P9, P10 the deflectors 13, 14 will be moved apart or towards each other
in the
direction indicated by the double arrow P11. By adjusting the distance between
the deflectors
13, 14 the pressure exerted on the brushes 3, 4 can be amended depending on
the desired
amount by which the bristles are pressed together. If the bristles are firmly
pressed together
no unwanted blowing will occur. However this might lead to extensive wear of
the brushes
and to an increase in the power needed to rotate the brushes. In case that the
deflectors 13, 14
do not press together the bristles enough to prevent all unwanted blowing, an
additional fan
can be used to apply vacuum near the surface 16, which vacuum will prevent
together with
the deflectors that unwanted blowing will occur. The deflectors 13, 14 will be
bendable to
accommodate for wear of the brush.
Fig. 7 shows another embodiment of the cleaning device 41 according to the
invention whereby the carriers 32, 33 of the deflectors 13, 14 are connected
near the side
edges by means of springs 42. These springs 42 will determine the force by
means of which
the deflectors 13, 14 are pressed against the brushes 3, 4. In case for
example that the brushes
3, 4 are replaced and the diameter of the brushes 3, 4 is slightly different
due for example to
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production tolerances, the deflectors 13, 14 can be moved towards each other
in the
directions indicated by arrows P12, P13 under the influence of the forces
exerted by the
springs 42 or can be moved apart against the forces exerted by the springs 42.
Fig. 8 shows a further embodiment of a device 51 according to the invention
whereby the deflectors 52, 53 are being made of flexible elements 52, 53 which
can
accommodate the differences in the diameter of the brushes 3, 4 according to
for example
production tolerances. The flexible elements 52,53 can be made of silicon
rubber, EPDM or
any other flexible polymer or material with desired mechanical and chemical
properties.
Fig. 9 shows another embodiment of a deflector 61 of a cleaning device
according to the invention which deflector 61 comprises a holder 62 which is
connected with
the housing 2 of the cleaning device 1 and flexible pens 63 extending parallel
to each other.
The pens 63 are pressed against the brushes 3, 4 with their ends remote from
the holder 62.
Depending of the thickness of the pens 63 and the distance between the pens 63
the deflector
61 will only function to prevent water being dropped back on the surface to be
cleaned 16 or
also for preventing unwanted blowing.
Fig. 10 shows another embodiment of a deflector 71 according to the invention
whereby a holder 72 is provided with flexible wires 73 along which water is
guided back to
the brushes 3, 4. If the distance between the wires 73 is relatively small and
the wires are stiff
enough, the wires 73 will also diminish the unwanted blowing.
Fig. 11 shows an embodiment of a deflector 81 according to the invention
whereby a holder 82 is provided with rigid pens 83. The deflector 81 will be
mounted by
means of a spring to the housing. Also this flexible deflector 81 will prevent
the dripping of
water and will diminish the unwanted blowing.
The bottom plate 21 and the deflectors 13, 14 can be made from any suitable
material like metal or plastic. The deflectors 13, 14 can be formed as a strip
connected to or
integrated with the housing 2.
Other examples of flexible deflectors are filaments like yarns, arranged like
a
comb, adjacent individual segments from flexible material like thin spring
metal sheet or
plastic sheet, fabrics, grids or meshes etcetera.
It is possible to make the distance between the surface and the axles of the
brushes 3, 4 adjustable to be able to amend the amount by which the bristles
are pressed
together. Preferably also the deflector is adjustable with respect to the
brush to adjust the
pressure between the deflector and the brush.
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It is also possible to suck the debris and water away from the entrance 12 by
means of a vacuum system.
For the bristles of the brush any kind of fibre, hair, wire-shaped element or
other kind of element is suitable which will be pressed together when
contacting a surface to
be cleaned.
If the deflector does not press firmly enough against the bristles of the
brushes,
the airflow away from the brush might also be prevented by means of a vacuum
system. In
such a case the deflector still prevents the leakage of water.
It is also possible to connect each deflector with a spring to the housing.
The
forces exerted by the spring can be in vertical direction, horizontal
direction or a combination
thereof.
