The present invention concerns the field of machines for floor treatment, such as cleaning and scrubbing, and in particular relates to the use of a vacuum squeegee assembly for collecting and lifting liquid from a floor surface during treatment. The squeegee assembly is typically towed behind a cleaning head. In the cleaning/ scrubbing operation a detergent-containing liquid is deposited on the floor surface in advance of a rotating cleaning head. The cleaning head scrubs the floor and dirt is dislodged from the floor and dissolved/entrained in the liquid. The dirty liquid is collected by a vacuum squeegee assembly which collects and lifts the dirty liquid thereby drying the clean floor.

Conventional squeegees comprise a pair of squeegee blades laid side by side as leading and trailing blades. The blades are nipped together at outer end regions. Both blades are curved with a leading blade following a slightly greater radius curvature than the trailing blade. The blades have a roof portion spanning the leading and trailing blades. The roof is crescent shaped when viewed from above and the blades thus adopt a lenticular plan configuration in which, at a middle region, the blades are spaced well apart whereas at the end regions the blades gradually taper together. The blades and roof together define a chamber which is vented to a vacuum source. The leading squeegee blade is typically formed with a series of apertures which permit passage of liquid collected by the leading blade as it is drawn over a wet floor. The liquid may thus be collected and enters the vacuum chamber, where is piles against the trailing squeegee blade. From the chamber, the liquid is entrained into a vacuum-induced airflow and drawn to a collection reservoir.

A problem for the efficient entrainment of the liquid in the squeegee vacuum chamber arises from the lenticular shape of the chamber. The central region of the chamber is where the liquid is collects after entering via the leading blade. The chamber in the central region has a greater cross-sectional area than the outer regions. For this reason the airflow speed drops and the airflow is therefore less well able to keep liquid entrained in the airflow and allow it to be conveyed from the chamber. This means that a more powerful vacuum source is needed to maintain the airflow speed in the wider regions of the vacuum chamber.

Attempts have been made to make the airflow more uniform in the squeegee's vacuum chamber by creating an airflow channel. In one example a step is formed in a roof chamber which provides a uniform cross-section channel see for example US7254867. US5911260 discloses a squeegee assembly in which a dirty liquid suction guide which is configured as an elongate shelf or flap in the suction chamber.

One problem with present squeegee arrangements is that the narrowing of the chamber at the outer ends thereof makes efficient entrainment of liquid difficult. This is at least in part due to the tendency of liquid to fill the chamber in these regions, thereby limiting the entrainment airflow in these regions.

The present invention seeks to provide more efficient liquid collection in a squeegee assembly, in particular by improving collection at outer end regions of the squeegee.

According to one aspect of the invention, there is provided a squeegee assembly for collecting liquid from a floor surface, the assembly comprising an elongate roof portion provided with depending leading and trailing elongate squeegee blades, the blades and roof portion together defining an elongate liquid collection chamber when horizontally disposed on the floor surface, the chamber being provided with a vacuum vent so that the pressure in the chamber may be reduced so as to permit airflow entrainment and removal of liquid gathered by the squeegee blades in the chamber, characterised in that the chamber roof portion is upwardly inclined towards an end region thereof so that a floor to roof portion chamber height measured at an end region of the chamber is higher than a corresponding chamber height measured at a mid region of the chamber.

Prior art squeegee assemblies typically have a planar and horizontal roof surface. By increasing the chamber height at the outer end region(s) relative to the middle region, the airflow path at the end regions is better maintained and water/cleaning liquid may be better entrained into the air drawn through under vacuum.

The roof portion is typically upwardly inclined towards each of the two end regions of the chamber, so that the chamber height at the two end regions is higher than the corresponding chamber height measured at a mid region of the chamber.

The end region chamber height is preferably between 0.3% and 4.0% higher than the I mid region height.

The incline is preferably a linear incline, although other configurations are possible, such as non-linear or stepped. The linear incline may amount to a rise from the horizontal of between 0.2 and 2.0 degrees. Preferably the incline is between 0.3 and 1.0 degrees. The blades and roof portion are typically arranged to provide a generally lenticular plan configuration when placed on the floor surface.

The vacuum vent is may be formed in a central region of the chamber roof portion, as is usual in the field.

The roof portion may be provided by a profiled insert disposed between the squeegee blades. This allows pre-existing squeegee assemblies to be readily modified so as to accord with the invention, by replacing the original insert with the insert of the invention.

In a particular embodiment the profiled insert has a generally lenticular plan, a generally horizontal upper surface and a lower surface having two upwardly tapering portions each extending from a mid region of the insert to respective outer regions of the insert, which lower surface provides the chamber roof portion.

The present invention also includes floor treatment, cleaning and scrubbing machines which comprise a squeegee assembly as herein described in general, or in the specific embodiment.

Thus according to a further aspect of the invention there is provided a floor cleaning machine which comprises at least one work head for treating a floor and a suction generator and further comprising a vacuum squeegee assembly as hereinbefore described according to any of the preceding claims, wherein the vacuum vent of the squeegee assembly is in fluid communication with the suction generator and the squeegee assembly is disposed so as to be drawn aft of said at least one work head.

The floor cleaning machine may be configured as a ride-on machine or a walk-behind machine. Preferably the machine includes drive means for propelling the machine over a floor surface. Suitable drive means include, without limitation, an electric motor which is adapted to drive a drive wheel.

Following is a description by way of example only and with reference to the accompanying drawings of one way of putting the present invention into effect.

In the drawings:- Figure 1 is a perspective view of a floor cleaning machine equipped with a vacuum squeegee collector.

Figure 2 is a perspective view of a squeegee assembly according to the present invention.

Figures 3A to 3D show sections through the assembly, at positions indicated by planes A to D shown in figure 2.

Figure 4 is a view from a front side of the squeegee assembly of the present invention, with squeegee blades removed so as to show the tapering profile of the chamber roof portion.

In figure 1 a floor cleaner is shown generally as 10. The cleaner is a ride-on machine which has a battery driven wheeled transport mechanism (not visible). Three rotary cleaning heads (not visible) face the floor and are disposed on an underside of the machine. The machine has a vacuum squeegee assembly 1 1 which is drawn behind rear wheels 12 of the machine. In use, a cleaning liquid is sprayed onto the floor surface as the floor is scrubbed. The liquid dissolves dirt and grease on the floor surface. The squeegee collects dirty liquid and lifts the liquid from the surface for storage in an internal dirty water reservoir (not visible) in the machine.

The squeegee assembly is described in more detail in the following. In figure 2 the squeegee 1 1 comprises a leading elongate rectangular scraper blade 20 which made from a strip of synthetic rubber plastics material. A lower floor-facing edge region 21 of the blade is formed with a plurality of spaced apart vertical slots or apertures 22. The apertures permit fluid communication to an interior vacuum chamber 23 (visible in figure 3). The scraper blade is curved so that outer end regions 24,25 of the blade are in advance of the middle region 26 of the blade. A trailing scraper blade 27 is of similar shape to the leading blade and similarly has a forward curve. The curve radius of the trailing blade is smaller than the leading blade. The blades taper together at outer end regions 24, 25 thereof, but are spaced apart towards their middle region, so that the blades together form a lenticular plan. The blades sit in an elongate, crescent shaped steel roof cap member 30 shown in section in figure 3. The roof cap member has an inverted generally U-section, with a crescent-shaped upper portion as shown in figure 3. A middle region of the roof cap member is formed with an upstanding outlet port 52. The vent provides fluid communication between the vacuum chamber and a vacuum air suction pump (not shown).

Between the scraper blades 20,27 and juxtaposed an underside of the roof cap member 30, is a roof portion insert 40. The roof portion insert is an elongate lenticular member, having a U-section, the sidewalls of which taper to a solid outer core region 41. The roof portion may be constructed of machined metal or moulded plastics material, for example. A middle region of the roof insert (not visible) is formed with a vertical bore which corresponds with, and is aligned with, the vacuum port 52 in the cap (see figure 2).

The underside 42 of the roof insert is provides a substantially flat elongate surface, which is inclined upwards from a middle region 43 thereof to each outer end region 44,45. The profile of the insert is shown side-on in figure 4. The surface is inclined upwards from the middle region at an angle of between +0.2 ⁹ and +2 ^S , in the preferred embodiment +0.5 ⁵ , from a notional horizontal defined by the floor 46. As will be seen by the series of cross- sections 3A, 3B, 3C and 3D, the heights (distances heights 1 , 2, 3 and 4) between the insert roof and the floor gradually rise from the middle region to the outer edge regions.

In use, liquid enters the leading blade's apertures and is collected in the squeegee chamber. The vacuum vent draws air into the chamber, also through the apertures. The increased chamber height at the outer regions thereof provides a larger flow path than if the roof height were parallel with the floor surface. Thus the vacuum induced air flow is better able to entrain liquid from the floor surface at the outer end regions.