Patent Description:
Known floor scrubbers typically have at least one workhead formed from an annular rotatable scrubbing portion including bristles or a polishing pad. The workhead(s) are driven by electric motors via a battery or mains electric power. Typically, 'wet' scrubbers have a cleaning fluid dispenser from which detergent or dilute cleaning solution can be distributed over the surface to be cleaned. Conventional motors used in floor scrubbers require a gearbox to deliver the required torque to the workhead. Consequently, power consumption is high and the multiple mechanical parts increase frictional resistance of the gearbox resulting in low transmission efficiency and increased likelihood of component failures.

<CIT> discloses a slim floor cleaner with a brushless DC motor, which is connected via a belt drive to an accessory coupling member for rotating various tools at a range of different speeds with examples ranging from <NUM> RPM to <NUM> RPM.

Thus, it is an object of the present invention to provide a floor treatment machine, such as a scrubber drier or autonomous cleaning machine, with a high efficiency drive mechanism operable within specific parameters optimised for the particular application.

According to one aspect of the invention there is provided a floor treatment machine for cleaning and/or treating a floor surface, the floor treatment machine comprising:.

The motor may comprise an outer housing or cover connected to the drive shaft and the magnet assembly may be attached to an internal surface of the outer housing / cover such that the magnet assembly surrounds the internal stator.

Thus, the outer housing or cover and the attached magnet assembly are rotatable around the stator. When energised, the motor provides a direct drive to the workhead without the need for a gearbox. Advantageously, this simplifies the internal structure of the motor, reduces the failure rate, and improves the efficiency of power transmission. As a result of the pre-selected dimensions of the motor, the rotary speed of the direct drive motor (an attached floor engaging workhead) is maintained at an optimal level, to provide ideal cleaning performance by the workhead, reduce vibration and minimise the noise generated, while still delivering the required torque.

The floor engaging workhead may be directly mounted on the drive shaft. Alternatively, the floor treatment workhead may be coupled to the drive shaft via one or more components movable with the workhead and drive shaft.

The floor engaging workhead may be directly mounted on the drive shaft or coupled thereto such that there are no parts between the drive shaft and the floor treatment workhead that are movable relative to the drive shaft and the workhead. Thus, the floor treatment workhead may be directly or indirectly mounted on the motor shaft without any gears positioned therebetween.

Advantageously the direct mounting of the workhead to the drive shaft increases the efficiency of the system by removing losses typically present in a gearbox drivetrain.

The dimensions of the motor that are pre-selected to achieve drive for the workhead within the required parameters include but are not limited to: magnetic surface area; diameter of the magnet assembly and stator; and/or depth of the magnet assembly and/or stator.

The dimensions of the motor may be selected such that the magnetic surface area is between <NUM><NUM> and <NUM><NUM>. The dimensions of the motor may be selected such that the magnetic surface area is between <NUM><NUM> and <NUM><NUM>.

The diameter of the motor may be between around <NUM> and <NUM>. The diameter of the motor may be between around <NUM> and <NUM>. The diameter of the motor may be between around <NUM> and <NUM>. The diameter of the motor may be approximately <NUM>. Thus, the diameter of the motor is typically greater when compared with conventional motors having a similar structure in order to provide the required torque to drive a workhead at the optimal rotational speed for a floor treatment machine.

The diameter of the motor may be selected at a specific value and the depth of the magnet assembly and/or stator may be varied according to the anticipated application. Thus, the motor may have a diameter of around <NUM> with a variable depth for the magnet assembly and/or stator to change the flux area according to the anticipated torque required for a particular application.

This allows for the production of a standard width motor with variable heights to adjust the flux area to account for the power requirements of a specific application. Advantageously this allows for production of a motor with known width/dimension in two axes, enabling designers of floor cleaning machines to allocate a known width/spacing for a motor within a body portion or floor/base unit of a machine relative to other components, while the flexibility remains to alter the rotational force available by varying the depth of the magnet assembly and only adjusting the height of the motor to change the flux area.

The depth of the magnet assembly and/or stator may be between around <NUM> and <NUM>. The depth of the magnet assembly and/or stator may be between around <NUM> and <NUM>. The depth of the magnet assembly and/or stator may be approximately <NUM> when the predetermined torque required for the application is up to around <NUM>. The depth of the magnet assembly and/or stator may be between <NUM> and <NUM> when the predetermined torque required for the application is up to around <NUM>.

The magnet assembly may comprise a plurality of high-density magnets. The rotatable annular magnet assembly may comprise a magnet arrangement of rare earth neodymium magnets.

The rotatable annular magnet assembly may comprise an arrangement of around <NUM> to <NUM> rare earth neodymium magnets. The rotatable annular magnet assembly may comprise an arrangement of between around <NUM> and <NUM> rare earth neodymium magnets. Advantageously, the high number of magnets increases the overall surface area of the magnetic field in order to achieve a high torque at a low speed.

The stator may comprise a substantially annular iron core with copper windings therearound. The stator may comprise a lamination stack with twelve cores with a fractional slot winding to achieve ten poles with three phases. The high number of poles is provided to achieve high torque with low speed rotation.

Preferably, the rotatable magnet assembly and the stator have a uniform annular spacing. The rotatable magnet assembly may be disposed at a spacing of between around <NUM> and <NUM> from the internal stator.

Thus, the air gap between the annular magnet assembly and the stator is minimised while ensuring contact between the rotor and stator is prevented, taking into account respective tolerances, dimensions and mechanical effects/vibration over time. Thus, the gap between rotor and stator is optimised.

The dimensions of the motor may be selected such that the floor treatment workhead is selectively rotatable at speeds up to <NUM> RPM. The dimensions of the motor may be selected such that the floor treatment workhead is selectively rotatable at speeds in the range between <NUM> and <NUM> RPM. The dimensions of the motor may be selected such that the floor treatment workhead is selectively rotatable at speeds in the range between <NUM> and <NUM> RPM.

The dimensions of the motor may be selected such that the magnet assembly, drive shaft and floor treatment workhead are selectively rotatable at speeds in the range between <NUM> and <NUM> revolutions per minute and provide a torque of up to around <NUM>. According to this example, the selected dimensions of the motor may be around <NUM> to <NUM> diameter and the depth of the magnet assembly and/or stator may be approximately <NUM> to <NUM> to achieve the output required of the motor.

The dimensions of the motor may be selected such that the magnet assembly, drive shaft and floor treatment workhead are selectively rotatable at speeds in the range between <NUM> and <NUM> revolutions per minute and provide a torque of up to around <NUM>. According to this example, the dimensions of the motor may be around <NUM> diameter and the depth of the magnet assembly and/or stator may be approximately <NUM> to achieve the output required of the motor.

The floor treatment machine may be configured as a wet floor treatment machine for the delivery of cleaning fluid to a floor surface, wherein the floor treatment machine comprises a cleaning fluid reservoir and an actuation mechanism coupled thereto for the selective delivery of cleaning fluid to the floor surface.

The drive shaft may comprise a throughbore arranged to selectively receive cleaning fluid for delivery to a floor surface in use. The hollow drive shaft may accommodate a cleaning fluid delivery line Thus, advantageously, the motor may comprise a centrally disposed hollow shaft through which cleaning fluid is selectively deliverable to the associated workhead.

The drive shaft throughbore may be fluidly coupled (via a cleaning fluid line or hose) to a cleaning fluid reservoir and the floor treatment machine may comprise an actuator to allow cleaning fluid from the reservoir to be delivered to the workhead via the throughbore and fluid delivery line or hose located in the drive shaft. A floor facing end of the throughbore within drive shaft may comprise a cleaning fluid outlet.

Thus, the cleaning fluid outlet may be advantageously centrally located on the workhead such that cleaning fluid is centrally deliverable to the workhead and entrained by the workhead during operation. The substantially central delivery of cleaning fluid has the advantage that the fluid is evenly distributed about the workhead and overspray is minimised such that the delivery, use and recovery of cleaning fluid is maximally efficient.

The floor treatment machine may comprise a reservoir for clean water and a waste fluid tank and the waste fluid tank may be fed by a squeegee suction collector which is disposed behind the workhead in use.

The floor treatment machine may be a manually guided machine. The floor treatment machine may be configured as a walk-behind floor scrubber.

The floor treatment machine may comprise a base portion provided with a rotatable floor-engaging workhead and a handle portion movably connected to the base portion such that the handle portion is arranged to guide movement of the base portion.

The floor treatment machine may be configured as a floor scrubber drier, comprising a cleaning fluid reservoir, a waste fluid tank, a source of suction and a squeegee collector which is fluidly connected to the waste fluid tank and disposed behind the base portion with respect to a forward direction of travel, wherein the suction source is coupled to the squeegee collector, which collects waste fluid from the floor surface and feeds it into the waste fluid tank.

At least one of the reservoir for clean water and the waste fluid tank may be disposed on the handle portion. Alternatively, at least one of the reservoir for clean water and the waste fluid tank may be disposed on the base portion. Optionally, both the reservoir for clean water and the waste fluid tank are disposed on the handle portion.

The handle portion may be connected to the base portion via an articulation which comprises a twin axis universal joint arrangement that permits the handle portion to recline, move up and down, and from side to side, while permitting torque to be applied via the handle portion to the base portion for swivel steering.

The floor treatment machine may comprise a walk-behind, ride-on or autonomous machine.

The floor treatment machine may comprise an autonomous machine whereby motion of the body portion and operation of the workheads are autonomously monitored and controlled by appropriate algorithms.

The floor treatment machine may comprise one or more workheads each provided with a motor comprising a centrally disposed rotatable drive shaft directly connected to the respective workhead. The floor treatment machine may comprise twin workheads.

The floor engaging workhead(s) may comprise a brush, scrubber pad, cleaning tool or the like. The workhead(s) may comprise a substantially cylindrical head. The workhead(s) may comprise a floor-facing disc with a selectable surface pad arranged for contact with a floor surface in use.

The workhead(s) and attached motor may be movable between a working configuration in which the / each workhead is deployed to act on the floor surface, and a stowed configuration in which the / each workhead is spaced from the floor surface.

The motor may be mounted an angle relative to an axis orthogonal to the floor in use. Thus, the floor engaging workhead located on the drive shaft may be inclined at an angle, such that a planar upper surface of the workhead is not parallel to the surface of the floor. Optional angular mounting of the motors in this way may generate propulsion for the floor treatment machine.

Advantageously, the invention provides a direct drive for a floor cleaning machine workhead that is efficient and constrained to drive the workhead within the optimum speed in revolutions per minute (RPM) to ensure thorough cleaning, while avoiding overspray when the workhead is used in conjunction with cleaning fluid. The pre-selected dimensions of the motor for the floor treatment machine further provide the required torque for the normal range of operations specific to the application of a floor scrubber drier or any type of floor treatment machine in which the direct drive motor is utilised to drive a floor engaging workhead.

The above described aspect of the invention may be combined with any other feature or embodiment described in the specification or shown in the figures.

Embodiments of the invention are now described with reference to the following drawings in which:.

The additional details or examples used to describe the drawings should not be construed as limiting the scope of the disclosed invention.

According to one described embodiment of the invention, a floor treatment machine is provided in the form of a manually operable, walk-behind, floor scrubber drier shown generally at <NUM> in <FIG> (in operational, transport and stowed configurations, respectively). The machine <NUM> has an upright handle portion <NUM> and a base portion <NUM>. The handle portion <NUM> is connected to the base portion <NUM> via an articulation which permits reclining of the handle portion <NUM>. The articulation comprises a twin axis universal joint arrangement which allows movement of the handle portion <NUM> while permitting torque to be applied to the base portion <NUM> via the handle portion <NUM> for swivel steering. A pair of primary support wheels <NUM> are provided at a rear end region of the base portion <NUM>. The articulation makes the machine <NUM> highly manoeuvrable and easy to steer and swivel around the primary wheel means <NUM>. One machine of this type is disclosed in <CIT>).

The base portion <NUM> includes a rotatable workhead <NUM> configured to clean a floor surface in use. The base portion <NUM> also carries a motor housing <NUM> which houses a direct drive motor shown generally at <NUM> in the figures. The motor <NUM> is arranged to rotatably drive the disc-shaped workhead <NUM>. The relative dimensions of the motors <NUM> and the workheads <NUM> in the embodiments shown in the figures differ. However, the key components of the motor <NUM> are similar in all embodiments and therefore like reference numerals have been used for equivalent features.

The motor <NUM> has a centrally disposed rotatable drive shaft <NUM> with a throughbore <NUM>, and a cover <NUM> connected to the shaft <NUM>. An inner surface of the cover <NUM> has a high-density magnet assembly <NUM> attached thereto in an annular arrangement. The magnet assembly <NUM> in <FIG> is made up of sixteen rare earth neodymium magnets. In <FIG> the magnet assembly may include thirteen rare earth neodymium magnets. According to other embodiments, different numbers of alternately polarised magnets <NUM> may be assembled within and attached to the inner surface of the cover <NUM>. The cover <NUM>, the drive shaft <NUM> and the magnet assembly <NUM> are interconnected and simultaneously rotatable.

The motor <NUM> also comprises a stator <NUM> in the form of an annular coil having copper windings <NUM> around a laminated iron core <NUM>. The stator <NUM> is disposed between the drive shaft <NUM> and the magnet assembly <NUM>. The stator <NUM> comprises a lamination stack with twelve cores <NUM> with a fractional slot winding to achieve ten poles with three phases. The stator <NUM> is supported on a motor mounting plate <NUM> which acts as a stator shell. The motor mounting plate <NUM> is connected to and contained within the protective motor housing <NUM> using fixing means inserted through the motor mounting holes <NUM> that are evenly spaced around the edge of the plate <NUM>. The stator <NUM> is positioned within the motor <NUM> under the cover <NUM> surrounding the drive shaft <NUM> and spaced from the rotatable components via ball bearing assemblies <NUM>. There is an air gap of <NUM> - <NUM> between the annular magnet assembly <NUM> and the stator <NUM> to ensure that there is no contact between the rotor and stator.

The floor treatment machine <NUM> also includes a circuit board (not shown) having a processor and the required electronic components for actuating and controlling the motor <NUM>. The stator <NUM> is electrically connected to the circuit board. During operation of the machine <NUM>, the motor <NUM> is controlled by the circuit board, which provides the required power to the stator <NUM> so that the cover <NUM> (and attached drive shaft <NUM> and workhead <NUM>) rotates around the stator <NUM> under the action of the magnetic force between the magnet assembly <NUM> and the annular coil.

Optimum operational parameters have been determined for the machine <NUM> according to a first embodiment: rotational speed of the workhead <NUM> is considered optimal between <NUM> and <NUM> RPM with an applied torque of up to <NUM>. In order to operate within these predetermined parameters, the diameter of the motor <NUM> is designed to be around <NUM> and the depth of the magnet assembly <NUM> and coil assembly <NUM> is <NUM>. This arrangement generates a flux area of <NUM>,<NUM><NUM>, ensuring that the motor <NUM> functions within the preselected parameters.

According to an alternative embodiment for a larger floor treatment machine: rotational speed of the workhead <NUM> is considered optimal between <NUM> and <NUM> RPM with an applied torque of up to <NUM>. In order to operate within these predetermined parameters, the diameter of the motor <NUM> is designed to be around <NUM> and the depth of the magnet assembly <NUM> and coil assembly <NUM> is between around <NUM> to <NUM>. This arrangement enables the motor <NUM> to function within the preselected parameters.

The floor treatment machine <NUM> had fluid tanks <NUM> mounted on the handle portion <NUM>. The fluid tanks <NUM> include a cleaning fluid reservoir and a waste fluid collection tank. The cleaning fluid reservoir is a repository from which cleaning fluid is selectively deliverable to the workhead <NUM> in use via a cleaning fluid connecting hose <NUM> (shown in <FIG>) within the throughbore <NUM> of the hollow drive shaft <NUM> of the motor <NUM>. Delivery of the cleaning fluid through the centre of the workhead <NUM> via the throughbore <NUM> in the drive shaft <NUM> provides a central cleaning fluid feed. This provides optimal central distribution of cleaning fluid to the workhead <NUM> resulting in an even cleaning action is use.

A brush guard <NUM> (shown in <FIG>) may extend towards the floor at least partially surrounding an exterior of the brushes mounted on the workhead <NUM>. The brush guard <NUM> can act to limit outward spray and provide protection for the brushes.

A squeegee suction collector assembly <NUM> is attached to a rear end region of the base portion <NUM>. The suction collector assembly <NUM> comprises a squeegee blade and carries an inlet connected to a waste fluid collection hose. The waste fluid collection tank is fed by the waste fluid collection hose from the squeegee assembly <NUM>. The collector assembly <NUM> can be moved between a stowed position (shown in <FIG>) and an operational position (shown in <FIG>).

Prior to use, in a non-working configuration, the handle portion <NUM> is lockable in a vertical or substantially vertical position, perpendicular with respect to the base portion <NUM> as shown in <FIG>. Such a locking mechanism is shown in <CIT>. The floor treatment machine <NUM> is transportable in the non-working configuration, in which the squeegee suction collector assembly <NUM> is in its resting configuration, tilted upwards away from the floor behind the machine <NUM>. The primary wheels <NUM> support the machine for transport, with the user steering the machine <NUM> using the handle portion <NUM>. The handle portion <NUM> may be tilted back during transport so that the workhead <NUM> is lifted from the floor surface as shown in <FIG>.

In use, the floor treatment machine <NUM> is moved into the operational configuration (<FIG>) in which the handle portion <NUM> is reclined and the workhead <NUM> is in contact with the floor surface. The workhead <NUM> is urged against the floor surface under the weight of the motor <NUM> within the housing <NUM> to provide a good scrubbing force.

During operation, the motor <NUM> is controlled by the electronic components on the circuit board causing selective energisation of the copper windings <NUM> of the annular coil or stator <NUM>. In the cleaning or operational configuration, power is delivered to the motor <NUM> to energise the copper windings <NUM> of the annular coil or stator <NUM>. The iron core <NUM> of the annular coil or stator <NUM> generates a magnetic field, forming a magnetic force within the magnet assembly <NUM>. This force drives rotation of the magnet assembly <NUM> attached to an interior of the cover <NUM> and also causes the connected drive shaft <NUM> and attached workhead <NUM> to rotate. The preselected dimensions of the motor <NUM> ensure that the driving force enables operation of the workhead <NUM> within the required parameters for optimum cleaning for the specific application and/or type of machine. In this way the invention provides an optimally functional floor scrubber drier with a direct drive motor <NUM> that is capable of efficient cleaning while simultaneously minimising power consumption.

Cleaning fluid is fed from the clean fluid reservoir through the fluid connecting hose <NUM> and drive shaft <NUM> of the motor for delivery in a central region of the workhead <NUM>. The optimised rotational speed ensures the cleaning fluid is worked into the floor surface rather than sprayed or splashed radially outwardly from the workhead, which can occur at higher rotational speeds. The synergistic effect of centralised fluid delivery and distribution at controlled rotational speed, ensure maximally efficient cleaning with less fluid wastage from overspray. Consequently, the machine <NUM> is operational for longer time periods without the requirement to cease operations for frequent cleaning fluid refills.

Thus, the workhead <NUM> scrubs the floor surface with cleaning solution at the controlled speed and providing the required torque. Waste water deposited behind the workhead <NUM> is retrieved by the suction collector assembly <NUM>. The collector assembly <NUM> uses the combined action of the squeegee blade and suction to collect waste fluid. The waste fluid connection hose transfers the waste fluid to the waste fluid tank.

The design, configuration and dimensions of the motor <NUM> ensure that sufficient torque is generated during use while providing rotation at the optimal speed for the floor scrubber drier <NUM>. This is achieved by increasing the flux area within the motor <NUM>. The direct drive from the motor <NUM> to the workhead <NUM> minimises losses associated with conventional motors having gear assemblies and therefore increases the efficiency of the floor scrubber drier <NUM> containing the direct drive motor <NUM>.

The tables provided in <FIG> provide a comparison of a typical brushless direct current electric motor with an internal rotor and a gear ratio of <NUM>:<NUM> and a brushless direct current motor with an external rotor, such as the motor <NUM> described with reference to the present embodiment. The rotational speed was maintained at a similar level for both motors to illustrate the differences in efficiency of the two motors. A percentage efficiency of each motor is provided in the final column of each table and the efficiency value is generated by comparing the required 'power in' and the measured 'power out', with these values represented in the penultimate two columns of each table. As demonstrated, the efficiency of the motor <NUM> provided in the scrubber drier <NUM> of the invention is far greater when compared with a conventional motor.

Thus, there are many advantages of providing a direct drive motor <NUM>: greater efficiency; reduced power consumption leading to reduced cost of use and lower environmental impact; less noise and vibration; and a simpler mechanism with lower potential for mechanical failure and greater longevity.

Modifications and improvements can be made without departing from the scope of the invention. Relative terms such as "outer", "internal", and/or "central" are used for illustrative purposes only and are not intended to limit the scope of the invention.

According to other embodiments, the motor <NUM> can be used in conjunction with any suitable alternative arrangement of components within a manually operable scrubber drier <NUM>. For example, the scrubber drier <NUM> may have a single or twin workheads each with an associated direct drive motor <NUM>. The machine <NUM> may be powered via a mains electricity supply or a battery. According to other embodiments the cleaning fluid reservoir and waste fluid tank may be separated and/or provided on the base portion <NUM> and/or the handle portion <NUM>.

Other, more compact arrangements for suction of waste fluid may be adopted in place of the squeegee suction collector. For each different arrangement of a floor treatment machine or compact scrubber drier the dimensions of the motor are preselected so that the motor <NUM> is configured to directly drive the workhead(s) <NUM> without the use of a gearbox at the required rotational speed and with the necessary torque.

Claim 1:
A floor treatment machine (<NUM>) for cleaning and/or treating a floor surface, the floor treatment machine (<NUM>) comprising:
a body portion provided with a rotatable floor-engaging treatment workhead (<NUM>) and a motor (<NUM>) comprising a centrally disposed rotatable drive shaft (<NUM>) coaxial with and connected to the floor engaging workhead (<NUM>), a stator (<NUM>) comprising an annular coil disposed around the drive shaft (<NUM>), and a rotatable magnet assembly (<NUM>) disposed at a spaced location around the stator (<NUM>), wherein the magnet assembly (<NUM>) is coupled to the drive shaft (<NUM>) and rotatable therewith; and
wherein the dimensions of the motor (<NUM>) are selected such that the magnet assembly (<NUM>), drive shaft (<NUM>) and floor treatment workhead (<NUM>) are selectively rotatable at speeds in the range between <NUM> and <NUM> revolutions per minute and provide a predetermined torque selected according to the application.