The present invention relates to the field of floor treatment machines for scrubbing, polishing, sanding or burnishing floors. In these machines one or more driven rotatable work heads (such as scrubbing brushes) are provided for agitating the floor surface. In particular the invention relates to a walk-behind machine provided with a handle for steering and guiding the machine as it travels over a floor surface.

EP2832277 (i-mop GmbH) discloses a walk-behind wet floor scrubber have two side- by-side work heads, each comprising disc-shaped floor brushes. There is a trailing squeegee and associated suction drive and reservoir for collecting liquid from the floor surface. The brushes support the weight of the machine and counter-rotate to provide propulsive force. The suction drive is disposed on a handle portion of the machine, along with a clean water reservoir for feeding a cleaning-liquid dispenser. The hand has dual pivot axes permitting up/down handle movement as well as side-to-side. A problem with these machines is that when not in use the elongate handle should be conveniently secured vertically against movement in the two axes, without having to be leant against another object.

The present invention seeks to provide a handle immobilisation mechanism which is effective for securing floor treatment machine handles against handle pivoting, whether in one axis or two axes.

These aims and others are met by the present invention in its various aspects, as will be evident from the following description.

According to one aspect of the invention there is provided a walk-behind floor treatment machine comprising:

a base portion provided with and supported by at least one rotatable work head for treating the floor,

a handle portion for steering or guiding the machine along a working direction of travel and adapted to be pivotable with respect to the base portion,

drive means for rotating the work head with respect to the base portion, floor-engaging wheel means for supporting the handle portion, the wheel means having a substantially transverse axis of rotation so as to permit travel in the working direction, the wheel means being coupled to the base portion by a linkage which permits vertical travel of the base portion and associated work head or heads with respect to the wheel means, but which provides transverse constraint to limit or prevent yawing of the base portion with respect to the wheel means.

A lower region of the handle portion may be pivotably connected to the wheel means via an articulated joint, the arrangement being such that the handle portion may be manipulated to act on the wheel means so as to yaw steer the wheel means about a yaw axis defined by the floor-engaging contact of the wheel means, the yawing of the wheel means causing the base portion to yaw in response to yaw steering.

A handle pivot lock mechanism may be provided in which the adoption of a

predetermined handle portion orientation permits one or more locking feature to act on one or more corresponding constraint feature so as to prevent pivoting movement of the handle portion with respect to the base portion. The predetermined handle orientation is preferably a vertical, or substantially vertical, orientation.

In the predetermined orientation the locking feature preferably becomes aligned with the constraint feature so as to permit mutual engagement. Conversely, when the orientation is not achieved misalignment prevents engagement of the features.

The locking feature or features may be one or more detent feature and the constraint feature or features are one or more indent feature. One of said features may be associated with the base portion or linkage, and the other of said features may be associated with the handle portion.

The pivoting of the handle may (at least) be up/down pivoting about a transverse axis, and the features may act to secure the handle portion against pivoting with respect to the transverse axis.

A user-operable lock-mechanism actuator is preferably provided which must be operated to allow the locking and constraint features to act on each other. This actuator may then be operated to unlock the features so as to release the handle portion.

The wheel means may comprise a wheel, roller or ball, preferably a single wheel, roller or ball, disposed at a lower region of the handle portion. The wheel means preferably has a fixed transverse axis of rotation. In one aspect the linkage comprises at least one strut, one end region of which is provided with a pitch pivotal connection to the wheel means, which connection is coaxial with the wheel means axis of rotation, and wherein an other end region of the strut is attached to the base portion.

The strut may be provided with a convex upper surface provided with the indent feature. The detent feature may be connected to a lower region of the handle portion for travel in an arc which corresponds to the profile of the convex upper surface, the arrangement being such that the detent feature can slide over the convex surface during up/down pivoting of the handle portion about the transverse axis.

A lock actuator may be provided to displace or urge the detent feature against the surface so when the detent feature and indent feature are aligned the detent feature projects into the indent so as to lock motion of the handle portion.

In a preferred arrangement there are two said struts disposed on either side of the wheel means in a generally parallel arrangement and two respective detent features, one for each strut. The two detent features may be provided by respective downwardly extending prongs of a locking member fork.

The convex surface may be provided with end stops at opposite ends thereof, which end stops limit travel of the detent along the convex strut profile so as to limit transverse pivoting of the handle portion to upper and lower arc boundaries.

The other end region of the strut or struts may be attached to the base portion via a pitch pivotal connection. The aforementioned pitch pivotal connections permit the vertical travel of the base portion with respect to the wheel means.

Said one or more rotatable work head typically support the base portion on the floor surface with the linkage permitting floating vertical travel of the work heads with respect to the wheel means.

The articulated joint permits side-to-side pivoting of the handle about the joint about an axis perpendicular to the pivot transverse axis. The side-to-side pivot of the articulated joint is provided at a location vertically / rearwardly spaced apart from the transverse pivot. A side-to-side pivot locking mechanism is provided in which entry of a traveller associated with the handle portion into a constraint feature prevents side-to-side pivoting. In a preferred aspect the traveller is a retractable shuttle accommodated in a lower end region of the handle portion. The shuttle may be movable from a retracted position in which side to side pivoting of the handle portion is permitted, and an extended position in which a distal end of the shuttle is constrained (e.g. between cheek features) which prevent pivoting from side-to-side of the handle portion.

The cheek features may define a generally vertical enclosure for accommodating the distal end of the shuttle, the shuttle traveling axially with respect to the handle portion, so that when the shuttle distal end is constrained the handle is dead centre of the side- to-side handle movement range.

The traveller/shuttle may be capable of acting on said locking member fork to cause locking of transverse handle portion pivoting as the side-to-side pivoting is locked.

The locking member fork and traveller may be connected by a pin and track engagement which provides vertical pin constraint and limited lateral pin freedom corresponding to side-to-side handle portion pivoting. The track is preferably arcuate in form.

Movement of the traveller towards the constraint condition may cause the pin to act on the track constraint, and wherein the track is provided in the locking member fork, so that movement of the traveller causes movement of the fork into indent engagement.

In this arrangement both handle portion pivot axes may be locked at the same time, conveniently with the handle portion in a generally vertical orientation.

The traveller or shuttle may be resiliently biased so that when actuated the

traveller/shuttle is urged towards its constraint position.

A distal end of the handle portion may be provided with a transversely oriented handle bar for the user to grip with a hand on each side of the bar. An upper end region of the handle portion may be provided with a handle position locking mechanism actuator.

The wheel means may comprise a wheel, roller or ball, singular or co-axial adjacent pairs. Preferably there is a single wheel, roller or ball, most conveniently disposed at a lower region of the handle portion. The wheel means may preferably have a fixed transverse axis of rotation (when placed on the floor). In other words there is no caster wheeling. The wheel or roller may however be adapted to tilt into a turn (so it tilts about an axis coaxial with the direction of travel).

The articulated joint may comprise a yoke which accommodates the wheel, roller or ball of the wheel means, which yoke preferably pivots about the wheel rotation axis.

The side-to-side pivot may be disposed on an upper bridging portion of the yoke. The side-to-side pivot may comprise a U-section bracket rotated 90 degrees with respect to the yoke and which receives a lower end of the handle, with a pivot pin bridging the bracket cheeks.

The base portion and associated work head(s) may be disposed at a front region of the machine. The wheel means may be disposed aft of the work head(s) and base portion with the linkage coupling extending between the wheel means and base portion (preferably generally centrally of machine or a centre region of the base portion).

In a preferred aspect of the invention, the machine is a wet scrubbing machine. It may be provided with a cleaning fluid reservoir and cleaning fluid delivery outlet. A squeegee liquid collector is preferably provided which is coupled to the machine by a trailing linkage. The linkage may permit up/down travel of the squeegee collector with respect to the wheels means. The trailing linkage is preferably pivotably coupled to the wheel means co-axially with the transverse axis of the wheel means. The machine may be provided with a squeegee suction drive and dirty liquid collection reservoir.

The squeegee collector may be able to adopt a transport (or storage) configuration in which the squeegee is pivoted down and depending from the trailing linkage (with the wheels/rollers on the floor), or folded up vertically away from the floor.

Forward propulsion of the machine is preferably provided by work head rotation. For transversely mounted rollers the direction of rotation controls forward or backward movement. For the preferred disc-shaped work heads which rotate about a vertical axis, the propulsion can be provided by using two work heads which counter-rotate. For a single such work head, the user can roll the handle slightly to roll the work head lightly which will cause improved traction on one side of the work head, which will induce forward propulsion if that side is the returning rotational side. The drive means may comprise one or more electric motors carried by the base portion and coupled to the work head or heads. In a preferred arrangement there are two generally disc-shaped work heads disposed side-by-side and oriented to rotate about a respective vertical axis of rotation. There are conveniently two electric motors, each disposed above its associated work head. Other arrangements are possible, such as a single motor which drives both heads via a pulley, chain or gear train. For simplicity a single motor for each head is preferred. The twin motors are configured and/or controlled to cause the work heads to counter rotate with respect to one another, thereby to provide a propulsive force. Scrubber brush driven machines are well known in the art. For example a single brush may be induced to drive by tilting the machine (base portion) onto the retreating side of a rotating disc-shaped, floor facing, work head.

The machine of the invention is preferably a walk-behind machine. To ease handling and guiding a distal end of the handle portion may be provided with a transversely oriented handle bar for the user to grip with a hand on each side of the bar. The handlebar may be provided with a speed control lever and cleaning fluid dispensing actuator.

Following is a description by way of example only and with reference to the

accompanying drawings of one mode for putting the present invention into effect.

In the drawings:

Figure 1 is a three quarter perspective view from above of a floor scrubber dryer that is in accordance with the present invention.

Figure 2 a perspective view, partially in section, of detail of the floor scrubber dryer of Figure 1 .

Figure 3a is a front partial cross-sectional view of a handle and wheel assembly used in the scrubber dryer with a handle locking mechanism shown in an unlocked

configuration.

Figure 3b is a front perspective three quarter view, partially in section of the handle and wheel assembly of figure 3a. Figure 4a is a front partial cross-sectional view of the handle and wheel assembly, but with the handle locking mechanism in a locked configuration.

Figure 4b is a front perspective three quarter view, partially in section of the handle and wheel assembly of figure 4b.

In Figure 1 , a floor scrubber dryer machine in accordance with the present invention is shown generally as 10. The machine comprises an elongate rectangular section handle portion 12. The handle portion 12 comprises a top end region and a bottom end region. A handlebar 13 is transversely mounted via a bore at the top end region of the handle portion 12. A control unit (not shown) is also provided at the top end region. During use the user walks behind the machine and guides it over the floor surface to be cleaned using the handlebar 13.

The bottom end region of the handle portion 12 is pivotally attached between upstanding ear portions of a generally U-section mounting bracket 14. The pivot is oriented fore-aft to enable side-to-side rotation of the handle portion relative to the bracket 14 about a pivot Axis 1 , as shown in the arrows A, A’. Axis 1 is substantially perpendicular to the length of the handle portion 12 and permits the handle to be swung transversely from side to side about the bottom end of the handle portion.

The bracket 14 has a lower region which is configured as a fork or yoke 17 formed by two spaced apart downwardly extending cheek plates. A guide wheel 18 is located between the cheek plates and mounted for rotation about an axle (not visible) which is co-axial with Axis 2. The wheel has a central hub and a circumferential solid rubber tyre. The axle permits the mounting bracket, fork and handle portion to be pivoted forward/backwards, up/down through an arc around the transverse Axis 2 provided by the axle.

In the present embodiment the wheel 18 is arranged to enable rotation about a single axis (Axis 2) and is otherwise fixed in position. However, in other embodiments, the wheel 18 may be configured to lean either left or right into a turn as a user manoeuvres the machine 18 around the floor surface. This can improve the handling of the machine 10. The same leaning could apply to other wheel means which may be used, such as a roller or a ball. As shown in figure 2 a pair of elongate, forwardly extending, spaced apart, parallel mounting struts 21 are pivotally attached at rear end regions thereof to opposite respective sides the wheel axle 19 projecting from either side of the wheel 18. Front end regions of each strut are attached to a pair of upstanding, spaced apart generally trapezoidal upright brackets 22 formed on a rectangular work base plate 23. The attachment is made via a pivot connection 24 having a transverse axis of pivoting rotation.

The rear end regions of the struts are each formed with a generally semi-circular (convex) hump 43, an edge of which defines an upper convex surface 40. The surface has at front and rear limits there of steps 41 and 42. A central portion of the surface is formed with a square cut-out (or indent) 44.

Within the bracket 14 and between the ear portions of the bracket is a fork member 45 provided with two depending prongs 46, 47. The lower ends of each prong are sized to be a fit for the indents 44 in the strut hump. The terminal face of each prong abuts the upper convex surface of the strut hump, as shown in figure 2.

A bridging portion of the fork member is formed with a cut-out elongate curved track 48 which has a radius defined by its distance below handle portion pivot Axis 1 (pivot pin 49). An upper surface of the fork member is formed with a concave saddle 56 which seats a lower end 57 of a shuttle 50. The shuttle is an elongate vertically oriented block which is accommodated within a cavity defined at a lower end region 51 of the handle portion, as is best shown in figure 3a. A lower end of the shuttle carried a track pin 52 which projects into the curved track 48. A mid-region of the shuttle is formed with a vertically oblong bore 53 which accommodated the Axis 1 pivot rod 49. The handle portion may pivot around the pivot pin 49 from side to side, by an extent limited by the arc of travel of the track pin in the track 48.

An upper end of the shuttle is attached to a cable 54. A coil spring 55 is accommodated in the upper end of the cavity. As shown in figure 3a and 33b the spring is compressed and acts between the top end of the shuttle and a bulkhead of the cavity, with the shuttle held retracted by the cable 54. The shuttle is a sliding fit in the cavity and on release of the cable restraint can travel downwards, to an extent limited by the oblong bore, as shown in figures 4a and 4b. A pair of internal side cheeks 56, 57 (figure 4a) of the prongs 17 of bracket 14 define an aperture into which the shuttle can impinge when the handle portion and shuttle are vertically oriented, as shown in figure 4a. Entry into this aperture of the lower end of the shuttle fixes or locks the handle portion in a vertical orientation (with respect to pivot Axis 1 ).

In parallel, the downwardly-shifted shuttle also shifts the fork member down too, by virtue of the pin acting on a lower edge of the track 48. Provided that the handle portion is vertical with respect to pivot Axis 2 (axle 19), the fork prongs 46, 47 engage with indents 44 in the upper edge of the struts 21. This immobilises the handle in a vertical orientation.

In this way a single actuation can be used to immobilise the handle portion against both fore/aft and side-to-side pivoting.

Returning to figure 1 , the base portion supports thereon two electric motors side by side which are a left scrubber electric motor 25 and a right scrubber electric motor 26.

A left scrubber brush 27 and a right scrubber brush 28 are attached under the base portion 23 to depending respective rotors (not shown) of the electric motors. The left scrubber and right scrubber are mounted to the rotors using conventional means such as a hub or chuck (not shown).

Each scrubber brush 27, 28 comprises a disc shaped base portion 29, and an annular array of fibre brushes 30, fixed an underside of the base portion. The scrubber brushes are arranged to enable rotation in opposite directions and about parallel vertical axes as shown in Figure 1 , which can provide forward or rearward propulsion

Pivotally mounted to the rear of the wheel 18 is a squeegee collector 30.. Two parallel trailing pivot arms are provided, coaxially mounted to the wheel axle 19. This allows the collector to follow surface undulations, but also allows it to be folded up when not in use. The collector 30 comprises an elongate lenticular form squeegee collector arm, of conventional design.. The squeegee interior (suction chamber) defined between forward and rear blades is in fluid communication (via port 31 ) with a suction drive (not shown) which may be mounted on the handle portion 12 or the base portion 23 so as to entrain and draw-up waste water that has passed through the scrubbers brushes.

Waste water drawn-up from the suction chamber is stored in a tank (not shown). The suction drive and tank may be positioned above the scrubber base portion, or on the handle portion 12, or at another convenient location on the machine 10. In the foregoing description and the associated drawings we have not shown features which will typically be present but which are not essential to the core aspects of the invention. These include a cleaning liquid reservoir and dispenser, a suction drive for the squeegee collector, or a dirty water reservoir fed by the squeegee collector. These are well known to the person skilled in the art so are not described in detail herein. For polishing machines or burnishing machines and the like no such ancillary features may be necessary.