FLOOR CLEANING DEVICE

Abstract

A liquid containing system for a floor cleaning device, the liquid containing system comprising an outlet having a plurality of openings (H) to allow a liquid (W) to be extracted by means of capillary force when a mopping substrate, e.g. a cloth (C), is mounted against the plurality of openings (H), after filling the liquid containing system being substantially closed but for the plurality of openings (H).

Claims

1. A liquid containing system for a floor cleaning device, the liquid containing system comprising an outlet having a plurality of openings to allow a liquid to be extracted by means of capillary force when a mopping substrate is mounted against the plurality of openings, after filling the liquid containing system being substantially closed but for the plurality of openings, wherein the openings have a diameter in range of 0.2˜0.9 mm, and preferably 0.2˜0.4 mm, and more preferably 0.3 mm.

2. A liquid containing system as claimed in claim 1, wherein the outlet is a replaceable part connectable to a reservoir of the liquid containing system.

3. A liquid containing system as claimed in claim 2, wherein the replaceable part is connectable to the reservoir at opposite ends of the replaceable part.

4. A liquid containing system as claimed in claim 2, wherein there are a plurality of replaceable parts, at least one of them being connected to the reservoir via connections that can be opened or closed.

5. A liquid containing system as claimed in claim 2, wherein a connection between the replaceable part and the reservoir has a diameter that is at least 6 mm.

6. A liquid containing system as claimed in claim 1, wherein the outlet comprises a first opening arranged to be in direct contact with the mopping substrate, and a second opening which is raised in comparison with the first opening.

7. A liquid containing system as claimed in claim 1, wherein the liquid containing system has a movable part that can be operated to obtain a volume reduction of the liquid containing system.

8. A liquid containing system as claimed in claim 1, further comprising an air valve that opens when an under-pressure in the liquid containing system exceeds a first threshold, and that closes when the under-pressure falls below a second threshold.

9. A liquid containing system as claimed in claim 1, wherein the mopping substrate has a mass per surface area that is substantially lower than 2.3 kg/m.sup.2, preferably in the range of 0.2 to 1.5 kg/m.sup.2, and more preferably in the range of 0.65-1.1 kg/m.sup.2.

10. A liquid containing system as claimed in claim 1, wherein a fiber diameter of fibers of the mopping substrate is in the range of 2-9 μm, preferably 2-6 μm, and more preferably in the range between 3-4 μm.

11. A liquid containing system as claimed in claim 1, wherein the pluralities of openings are in a strip having a thickness that is preferably of the order of 0.05 to 1 mm and more preferably in the range of 0.1-0.2 mm.

12. (canceled)

13. (canceled)

14. A floor cleaning device comprising a liquid containing system as claimed in claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIGS. 1 and 2 illustrate a first embodiment in accordance with the present invention;

[0033] FIG. 3 shows an embodiment of the present invention having double layers of cloth;

[0034] FIGS. 4 and 5 show embodiments of the present invention for use without and with vacuum cleaner, respectively;

[0035] FIGS. 6 and 7 show embodiments of the present invention with replaceable strips;

[0036] FIG. 8 shows how the replaceable strip can be flushed;

[0037] FIGS. 9 and 10 show further embodiments of the present invention with replaceable strips; and

[0038] FIGS. 11 and 12 show embodiments of the present invention with different placement of holes in the strips.

[0039] DESCRIPTION OF EMBODIMENTS

[0040] FIGS. 1 and 2 illustrate a first embodiment in accordance with the present invention. A main element of an embodiment of this invention is a small reservoir R which has an airtight upper side and a lower side which contains holes H to let water W (or another cleaning liquid) out and air in. The cloth C for cleaning is placed directly against these holes. When the reservoir R is filled, the liquid will be absorbed by the cloth C. The amount of liquid that is taken up by the cloth C depends mainly on the surface area of the holes H and the material of the cloth C. FIG. 2 shows a magnified view of the encircled area in FIG. 1, showing how the cloth C absorbs water W from the reservoir R by capillary pull/suction.

[0041] The cloth C may be made from Nylon 6. An optimized cloth has a mass per surface area that is substantially lower than 2.3 kg/m.sup.2, preferably in the range of 0.2 to 1.5 kg/m.sup.2 and more preferably in the range of 0.65-1.1 kg/m.sup.2. This will result in a cloth that can hold less water than usual, so that an amount of water distributed by the cloth to the floor in an initial stage when a wet cloth is mounted on the floor cleaning device will not be much higher than an amount of water distributed by the cloth to the floor later on, when the cloth is continuously wetted by the water in the reservoir. A reduction of the fiber diameter from 6-9 μm to a diameter in the range of 2-9 μm, preferably 2-6 μm, and more preferably in the range between 3-4 μm will reduce the flow rate to values in the range of the desired range to match the flow rate deposited on the floor with the flow rate delivered through the holes and cloth.

[0042] The surface area that can be cleaned is only limited by the volume of the reservoir R. A wetness of the floor of approximately 2 g/m.sup.2 means that for cleaning an average house of 100 m.sup.2 hard floors, a reservoir of 200 ml is sufficient (rounding off and assuming that water of 1 g=1 ml). To keep the impact of water column height as small a possible a reservoir with a low height is preferred.

[0043] For the best equal distribution of liquid to the cloth C, the holes H needs to be spaced apart as close as possible or evenly distributed across the whole width of the cloth or device.

[0044] For a small mop with a width of 250 mm and holes spaced apart at 5 mm it means 45 holes are needed. For a flow of 35 ml/min with 45 holes, we need holes with a diameter of 0.3 mm.

[0045] The surface tension of the liquid influences how deep the liquid in each hole is penetrated. Using detergents in the liquid makes a big impact on the surface tension. To reduce this effect it is preferred to have a strip that is as thin as possible where the holes are placed. The thickness of the strip is preferably of the order of 0.05 to 1 mm and more preferably in the range of 0.1-0.2 mm. Test shows that a strip with thickness of 0.1 mm the effect of using detergent (other surface tension of the liquid) has no impact on the wetness. Preferably the material of the strip is hydrophilic. Preferred materials are metal or plastic coated with a hydrophilic coating. Preferably, the holes are in a protruding area of the strip.

[0046] While a strip of e.g. 0.1 mm is rather thin, to ensure sufficient strength other parts of the outlet where the holes are not present are thicker by mounting an additional material (metal, plastic) against the thin material strip either at the inside or at the outside. In the embodiments of FIGS. 6-12 below with a second reservoir R2, the walls of the reservoir R2 could be made from this thin material, with the additional material placed against this thin strip material at least at the top wall and the side walls, and preferably also at the bottom except where the strip with the holes protrudes from the remainder of the thin material.

[0047] The holes may be made by etching. The hole shape is preferably purely straight or slightly converging. If as a result of etching from both sides the hole shape also has a diverging part, an angle of the hole side to the vertical should not exceed 60°, and preferably does not exceed 30°.

[0048] Because the type of cloth can influence the wetness, cloths with several different layers can be used to have perfect water distribution (e.g. small soft microfibers) and also good cleaning or scrubbing performance on the floor (e.g. thick, hard, polyester fibers). FIG. 3 shows an embodiment using a multi-layer cloth having 2 layers Cl, C2. Preferably, the cloth layer C2 in contact with the floor contains thick polyester fibers of diameter of 50-75 μm.

[0049] Referring to FIG. 4, showing an embodiment with reservoir R, cloth C and fill opening FO, because of the simplicity, the small dimensions and no need for additional interfaces for liquid flow or electric means, this solution is very suited to be placed directly above the floor at the bottom end of the stick of an appliance without a vacuum cleaner. With this architecture and the exact control of wetness of the floor this solution is perfectly suited to combine with vacuum nozzles, as illustrated in the embodiment of FIG. 5, which shows an embodiment having a vacuum nozzle N, reservoir R, cloth C, and tube T to canister. In that case the cloth not only remains continuously wet but also keeps clean during use especially when a suction channel is created at both sides of the cloth.

[0050] An advantageous embodiment of this invention involves a replaceable strip that has a plurality of substantially evenly spaced openings to have an evenly distribution of the liquid to the cloth and where the liquid transport out of these openings makes use of the capillary force of a wick type material. This wick type material is also the cloth for cleaning and can be washed after use.

[0051] It is difficult to make a liquid/air tight connection from the strip to the reservoir which is replaceable. Sealing a large surface is difficult. Therefore the strip is placed with a fixed connection in a second reservoir. This second reservoir can be made very small.

[0052] Referring to FIG. 6, this second reservoir R2 is connected with a simple round sealing S to the main reservoir R. In this case the water distribution/wetness of the floor can easily be adjusted by replacing the second reservoir by another with other dimensions of the evenly spaced openings or other number of openings. When the strip in the second reservoir is clogged or broken it can easily be replaced without high cost of replacing or much effort of cleaning the full system.

[0053] Referring to FIGS. 7 and 8, it is preferred to have two inlet openings of the second reservoir R2 to reduce the chances on air entrapment in second reservoir. The two inlet openings of the second reservoir improves cleaning of the second reservoir because it can be flushed under the tap, as shown in FIG. 8. The second reservoir R2 is the part that has the small openings which might clog. To prevent air bubbles from clogging the second reservoir R2 or from covering multiple holes, dimensions of its cross-section should be at least 3×3 mm, and preferably at least 5×5 mm. Obviously, the cross-section does not have to have a square shape; a circular shape would do as well, with a diameter of at least 4 mm and preferably 6 mm. Inlet hole(s) of the second reservoir R2 preferably have a diameter of at least 6 mm.

[0054] While in FIGS. 7 and 9-12, the ceiling of the second reservoir R2 is straight horizontal, in alternative embodiments, to easily allow any air bubbles to leave the second reservoir R2, it may be advantageous if the ceiling of the second reservoir R2 is slanted. Several options are possible, viz. that e.g. the left-hand connection to the main reservoir R is higher than the right-hand connection to the main reservoir R, or that the ceiling is wholly or partially vertically V-shaped in that the height of the second reservoir R2 at a position between the connections to the main reservoir R (which does not need to be in the middle) is lower than the height of the second reservoir R2 at the connections to the main reservoir R. An angle of the ceiling with regard to the horizontal is preferably in the range between 0.5° and 10° and more preferably in the range between 1° and 5°.

[0055] To further facilitate air bubbles from leaving the second reservoir R2, it could have a horizontal V-shape, i.e. be pointed in the forwards direction of movement of the floor cleaning device. Alternatively, the second reservoir R2 could be mounted to the main reservoir R in such a way, that e.g. the left-hand connection to the main reservoir R is positioned before the right-hand connection to the main reservoir R in the direction of movement of the floor cleaning device. Preferably an angle of the V-shape compared to a straightforward line-formed second reservoir R2, or an angle at which the second reservoir R2 is mounted is in the range of 2°-70° and more preferably in the range of 10°-30° . Preferably the connections in the second reservoir R2 to the main reservoir R have a sufficiently low radius of curvature, in order that any air bubbles can easily leave the second reservoir R2.

[0056] Referring to FIGS. 9 and 10, two-side filling enhances also different architectures of the first reservoir(s) R. The main element of this embodiment is a small second reservoir R2 which contains openings to let water out and air in at the lower side. This second reservoir R2 is connected via the upper sided to a first reservoir R at the lower side which has an airtight upper side. The cloth C for cleaning is placed directly against the openings of the second reservoir. The liquid W in the first reservoir R flows to the small reservoir R2 through two big holes which are present on the opposite ends of the strip or wherever desired for optimum performance. Thereafter, this water/liquid W is absorbed by the mop/cloth C through the series of holes in the strip. For the best equal distribution of liquid to the cloth, the openings needs to be spaced apart as close as possible.

[0057] In an embodiment, there are two small reservoirs R2 in parallel. A preferred embodiment would be that one small reservoir has less than 15 holes of 0.2˜0.9 mm, and preferably 0.2˜0.4 mm diameter while another small reservoir has between 15 and 30 holes of 0.2˜0.4 mm diameter. The small reservoir with less than 15 holes has no sealing mechanism on the inlets and is therefore always “on”. This setting can be used as the low setting for e.g. wooden floors. The other small reservoir with between 15 and 30 holes can be opened and closed by a sealing mechanism by activating a switch and/or valves. When the switch is opened the setting can be used as the “high” setting for e.g. tiles. The switch is situated at the outside of the reservoir and is watertight and airtight connected with a valve mechanism inside the reservoir. The mechanism activates two sealing elements which open and close the inlets to the second reservoir concerned. This embodiment would also be very useful in a context without a plurality of openings H to allow a liquid W to be extracted by means of capillary force when a mopping substrate C is mounted against the plurality of openings H.

[0058] FIGS. 11 and 12 show other embodiments of the invention. As mentioned above, the water regulation can be changed by influencing the placement of holes in the base of the reservoir. The holes H can all be placed in the base evenly as shown in FIG. 11 or may be placed in a manner such that height of one hole adjacent to the other is variable i.e. there is a step on which the hole is constructed and can be seen in FIG. 12. This placement of holes can influence the wettability in that holes H1 which are in the base and come in contact with the cloth C help to dispense the liquid W while the holes H2 which are raised act as air vents. The choice and placement of the holes H1, H2 at varying height can be randomly arranged and need not be adjacent. For example, as shown in FIG. 12, only the first and last holes in the series of holes could be designed as raised holes H2 while the other holes H1 are in the base. Thus, a system that is fully closed but for the plurality of opening holes H1 in contact with the cloth C is not required. In view of surface tension, air vent holes allowing air to enter below the water level can be larger (diameter in the range of 0.2 to 0.9 mm and preferably in the range between 0.3 and 0.6 mm) than holes allowing air to enter above the water level (which should be about 0.2 mm in diameter). The air hole may have a variable controllable cross section to regulate water flow. A needle valve may do.

[0059] Another option to prevent a significant suction pressure in the tank is by increasing the pressure in the tank by e.g. a volume reduction by e.g. a membrane. For instance, a membrane open to the air but with a sufficient resistance can be introduced in the upper wall of the reservoir R. A flexible membrane can be combined with a separate air vent. A convex membrane can be operated by a consumer, e.g. by pressing the convex membrane by foot. The required volume change that the membrane should reach is preferably in the order of 0.5-10% of the air volume and more preferably in the range of 1-5% of the air volume. The material of the flexible membrane can be a rubber or other elastic materials. Note that the advantage of a flexible membrane in combination with a separate air vents is that due to air entering the reservoir R via the separate air vents the flexible membrane will move back to its original convex position so that the boost function can be operated by the consumer once more.

[0060] Another embodiment is that the volume change is permanent. This can be done also in many different options, for instance by a cylinder that is forced in the air compartment of the tank. We further include that it is also possible to regulate the suction pressure in the air in the tank to the desired levels of 3-20 mbar, preferably 6-12 mbar via a direct contact with the air. When this contact has a sufficient resistance the system is open to the air but still it is possible to ensure that the suction pressure is at the required levels of 3-20 mbar, preferably 6-12 mbar. An embodiment is for instance a membrane with a sufficient air resistance.

[0061] Preferably, to ensure that the under-pressure in the reservoir R does not become too high, the reservoir R is provided with an air valve that opens when an under-pressure in the reservoir R exceeds a first threshold of e.g. 25 mbar (preferably 20 mbar, even more preferably 15 mbar), and that closes when the under-pressure falls below a second threshold of e.g. 0 mbar (preferably 6 mbar).

[0062] To prevent air from filling the holes H1, it appeared advantageous if the holes are shaped such that from outside to inside, they first have a relatively narrow diameter of about 0.3 mm for the thickness of a bottom strip of about 0.1 mm, and then a relatively wide diameter of at least 1.5 to 2 times the relatively narrow diameter; this relatively wide diameter would be about 15-60% of a cross section of the second reservoir R2.

[0063] 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 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. An opening may be filled with a wick. In the device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.