FIELD OF THE INVENTION
[0001] The invention relates to a wet cleaning device.
BACKGROUND OF THE INVENTION
[0002] Hard floor cleaning is traditionally done by first vacuuming the floor, followed
by mopping it. Vacuuming removes the coarse dirt, while mopping removes the stains.
These days there are more and more appliances on the market that claim to vacuum and
mop in one go. Also robot vacuum cleaners offer the solution of vacuum cleaning and
mopping the floor. For this a water tank with mop is attached towards the (vacuum
cleaning) robot.
[0003] US2017367552 discloses a self-moving floor treatment device that comprises a machine body base
and a water tank. A cleaning cloth is attached onto the bottom of the water tank,
and the water tank is connected to the bottom surface of the machine body base in
a manner of floating up and down. By mounting the water tank on the machine body base
in. a floating manner to leave a certain gap therebetween, the water tank and the
cleaning cloth can float up and down within a certain range of space. Because the
force that actually acts on the floor is just the gravity of the water tank and the
cleaning cloth themselves and does not comprise the gravity of the machine, compared
with a common product, the friction force between the cleaning cloth and the floor
is reduced, the phenomenon that the machine slips on the floor with water can be effectively
avoided, the floor cleaning efficiency is improved and the obstacle crossing ability
of the machine with the water tank is improved.
SUMMARY OF THE INVENTION
[0004] It is, inter alia, an object of the invention to provide an improved wet cleaning
device. The invention is defined by the independent claims. Advantageous embodiments
are defined in the dependent claims.
[0005] One aspect of the invention provides a wet cleaning device, comprising a mopping
unit for wet cleaning a surface, and an arrangement for increasing a pressure of the
mopping unit to the surface by means of suction. In one embodiment, the arrangement
includes a hose at a side of the mopping unit, the hose having an opening for applying
suction to the surface. The hose may be present at opposite sides of the mopping unit.
Alternatively, the hose may be present around the mopping unit. Preferably, a suction
power of the arrangement is controllable. Advantageously, the suction power is controllable
in dependence on a detection of stains, a speed of the wet cleaning device, and/or
a type of the surface. If the wet cleaning device is formed by a mopping robot vacuum
cleaner, the suction for the arrangement is advantageously a part of a suction generated
for vacuum cleaning.
[0006] The invention is based on the recognition that wet cleaning devices like robot vacuum
cleaners are preferably not very heavy, so that a user can easily pick them up. For
mopping a surface (e.g. a floor), often some pressure is needed on the surface to
be able to remove hard stains. Here we encounter a contradiction. The wet cleaning
device needs to be low in weight to be easily lifted, but on the other hand, it should
provide enough pressure on the floor to enable the wet cleaning device to mop the
surface properly. To overcome this contradiction, it is necessary to provide a way
to apply force on the ground without making the wet cleaning device heavier.
[0007] One aspect of this invention will enable the wet cleaning device to give an increased
pressure on the ground while mopping, while staying light in weight. Embodiments of
the invention provide an area of under-pressure around the mopping unit so that the
mopping unit will suck itself to the ground. In a robot vacuum cleaner embodiment,
the under-pressure can advantageously be generated by leading a part of the airflow
of the vacuum cleaner through a tube system around the mop.
[0008] These and other aspects of the invention will be apparent from and elucidated with
reference to the embodiments described hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009]
Fig. 1 shows a bottom view of an embodiment of a wet cleaning device in accordance
with the invention; and
Fig. 2 shows a cross-section of the embodiment of Fig. 1.
DESCRIPTION OF EMBODIMENTS
[0010] The embodiment of Figs. 1 and 2 relates to a wet cleaning device WCD formed by a
mopping robot vacuum cleaner. As usual, the mopping robot vacuum cleaner has wheels
W, a nozzle N with an optional rotating brush B, and a mopping unit MU. The mopping
unit MU has a liquid tank (not shown) and a (replaceable) cleaning cloth. In accordance
with the invention, a suction tool ST is provided at a side of the mopping unit MU.
In the embodiment shown, the suction tool ST is formed by a hose having multiple openings
around the mopping unit MU. Alternatively, the hose may have a slit-shaped opening.
The hose may be made of rubber or some suitable plastic or other suitable material.
The hose may be glued to the mopping unit MU.
[0011] As shown in Fig. 2, as usual for vacuum cleaners, dirty air from the nozzle N is
guided to a dirt separation and collection unit DC, through which an airflow is generated
by a fan F. In accordance with an embodiment of the invention, part of the airflow
generated by the fan F is used to generate suction for the suction tool ST. A valve
V is present to control how much airflow can be used for the suction tool ST. The
valve V may be formed by means of a clamp around a hose: if the hose is compressed
by the clamp, less suction is available for the suction tool ST. Advantageously, the
amount of suction available for the suction tool ST depends on a detection of stains
(stain present => more suction), a speed of the wet cleaning device WCD (too low speed
=> reduce suction), and/or a type of the surface. To control the valve, a processor
(anyway present in a robot cleaner) receives data (e.g. from a camera (not shown),
and has software that can determine the presence of stains and the surface type from
the camera image. This software may involve artificial intelligence based on a trained
neural network. The wheel speed can be derived e.g. from an amount of current drawn
by a motor that rotates the wheels W: if the current is relatively high, the motor
has to work hard, so that it makes sense to reduce the suction for the suction tool
to reduce friction.
[0012] It should be noted that the above-mentioned embodiments illustrate rather than limit
the invention, and that those skilled in the art will be able to design many alternative
embodiments without departing from the scope of the appended claims. In the above
examples, a rectangular robot vacuum cleaner has been shown with a rectangular mopping
unit MU. Obviously, the wet cleaning device may have a different shape (e.g. round),
and the same holds for the mopping unit MU, which may e.g. have the shape shown in
US2017367552. In the embodiment shown, the mopping unit MU is surrounded by the suction tool ST,
but in other embodiments, the suction tool ST is just present at a side or at opposite
side of the mopping unit MU. The suction tool ST does not need to be along a side,
i.e. it does not need to have an elongated shape, as long as it results in the mopping
unit MU exercising an increased pressure on the surface. The wet cleaning device of
the present invention may also be arranged for cleaning (vertical) surfaces like windows
or walls. The wet cleaning device of the present invention does not need to have a
vacuum cleaner function. And if the wet cleaning device does have a vacuum cleaner
function, it may or may not use the vacuum cleaner fan F for creating suction to increase
a pressure of the mopping unit to the surface; a separate low-power fan may be used
for this purpose, and this may result in the advantage that a better control of mopping
pressure may be achieved, independent of vacuuming activities. A wet cleaning device
having a vacuum cleaner function may have different operation modes: (1) only vacuum
cleaning, (2) only wet cleaning, and (3) both vacuum cleaning and wet cleaning. In
the second mode, use of a separate suction unit for generating under-pressure may
result in the advantage that less energy is consumed. In the claims, any reference
signs placed between parentheses shall not be construed as limiting the claim. The
word "comprising" does not exclude the presence of elements or steps other than those
listed in a claim. The word "a" or "an" preceding an element does not exclude the
presence of a plurality of such elements. The invention may be implemented by means
of hardware comprising several distinct elements. In the device claim enumerating
several means, several of these means may be embodied by one and the same item of
hardware. Measures recited in mutually different dependent claims may advantageously
be used in combination.
1. A wet cleaning device (WCD), comprising:
a mopping unit (MU) for wet cleaning a surface, and
an arrangement (ST) for increasing a pressure of the mopping unit to the surface by
means of suction.
2. A wet cleaning device (WCD) as claimed in claim 1, wherein the arrangement (ST) includes
a hose at a side of the mopping unit (MU), the hose having an opening for applying
suction to the surface.
3. A wet cleaning device (WCD) as claimed in claim 2, wherein the hose is present at
opposite sides of the mopping unit.
4. A wet cleaning device (WCD) as claimed in claim 2, wherein the hose is present around
the mopping unit.
5. A wet cleaning device (WCD) as claimed in any of the preceding claims, wherein a suction
power of the arrangement is controllable.
6. A wet cleaning device (WCD) as claimed in claim 5, wherein the suction power is controllable
in dependence on a detection of stains.
7. A wet cleaning device (WCD) as claimed in claim 5 or 6, wherein the suction power
is controllable in dependence on a speed of the wet cleaning device.
8. A wet cleaning device (WCD) as claimed in claim 5, 6 or 7, wherein the suction power
is controllable in dependence on a type of the surface.
9. A wet cleaning device(WCD) as claimed in any of the preceding claims, wherein the
wet cleaning device is formed by a mopping robot vacuum cleaner, the suction for the
arrangement being a part of a suction generated for vacuum cleaning.