REFERENCE TO RELATED APPLICATIONS

This application claims the priority of United Kingdom Application No. 1618246.1, filed Oct. 28, 2016, the entire contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a cleaning appliance. The cleaning appliance is preferably a handheld cleaning appliance, and is preferably a surface treating appliance. In preferred embodiments of the invention, the appliance is a dental cleaning appliance. In a preferred embodiment, the appliance is an electric toothbrush having a fluid delivery system for delivering a fluid to the teeth of the user. This fluid may be toothpaste, or a fluid for improved interproximal cleaning. Alternatively, the appliance may not include any bristles or other elements for brushing teeth, and may be in the form of a dedicated interproximal cleaning appliance. The invention also relates to a cleaning tool for use with a dental cleaning appliance.

BACKGROUND OF THE INVENTION

Electric toothbrushes generally comprise a cleaning tool which is connected to a handle. The cleaning tool comprises a stem and a brush head bearing bristles for brushing teeth. The brush head comprises a static section which is connected to the stem, and at least one moveable section which is moveable relative to the static section, for example with one of a reciprocating, oscillating, vibrating, pivoting or rotating motion, to impart a brushing movement to bristles mounted thereon. The stem houses a drive shaft which couples with a transmission unit within the handle. The transmission unit is in turn connected to a motor, which is driven by a battery housed within the handle. The drive shaft and the transmission unit convert rotary or vibratory motion of the motor into the desired movement of the moveable section of the brush head relative to the static section of the brush head.

It is known to incorporate into an electric toothbrush an assembly for generating a jet of fluid for interproximal cleaning. For example, U.S. Pat. No. 8,522,384 describes an electric toothbrush in which the handle of the toothbrush defines a fluid chamber for storing a liquid such as water, and a slidable cover for enabling the fluid chamber to be accessed for replenishment by a user. A fluid path connects the fluid chamber to a nozzle located on a static portion of the brush head. A pump located within the fluid path is actuated upon user operation of an actuator on the handle to pump fluid from the fluid chamber to the nozzle for release under pressure from the nozzle.

SUMMARY OF THE INVENTION

In a first aspect, the present invention provides a dental cleaning appliance comprising a nozzle for delivering a burst of working fluid to the teeth of a user; and a fluid conduit for conveying working fluid to the nozzle; wherein the nozzle comprises a fluid chamber extending about a longitudinal axis and a channel for conveying working fluid from the fluid chamber to a fluid outlet from the nozzle, the fluid chamber comprising a fluid inlet for conveying working fluid into the fluid chamber at an angle to the longitudinal axis.

Each burst of working fluid preferably has a volume which is preferably less than 1 ml, more preferably less than 0.5 ml. In a preferred embodiment, the volume of the burst of working fluid delivered to the teeth of a user is in the range from 0.1 to 0.4 ml, and is preferably around 0.25 ml.

Within the fluid chamber, the nozzle thus generates angular momentum of the working fluid about the longitudinal axis of the fluid chamber. The working fluid is conveyed to the fluid outlet of the nozzle by a channel extending between the fluid chamber and the fluid outlet. The burst of working fluid is projected outwardly from the fluid outlet and breaks up to form a spray. The spray of working fluid expands out of the fluid outlet of the nozzle and is generally conical in nature after the fluid outlet. The working fluid ejected from the nozzle is encouraged to break up and form a divergent spray with droplets because sufficient angular momentum and flow disruption has been introduced into the flow within the fluid chamber. This action, together with sufficient momentum in the general direction of the flow, enables matter located within an interproximal gap of a user's teeth to be dislodged by the working fluid.

We have found that delivering such a burst of working fluid as a spray of droplets, that is formed from a nozzle having an angled inlet as opposed to an axial inlet, delivered to an interproximal gap is more effective at dislodging matter therein. This can enable a user to reduce the number of bursts of working fluid which are required to dislodge matter therein, reducing the time required to perform an entire teeth cleaning operation and reducing the risk that a fluid reservoir for supplying working fluid to the nozzle will become exhausted prior to the completion of the teeth cleaning operation.

The fluid inlet is preferably arranged to convey the fluid into the fluid chamber along a path which is located in a plane which is substantially orthogonal to the longitudinal axis. The fluid inlet is preferably arranged to convey the fluid into the fluid chamber along a path which is spaced from, or offset from, the longitudinal axis. The fluid inlet is preferably in the form of a tangential inlet for conveying the fluid substantially tangentially into the fluid chamber. The fluid chamber preferably has, in a plane which is orthogonal to the longitudinal axis, a cross-section which is substantially circular in shape. The fluid chamber may be cylindrical, spheroidal or spherical in shape. However, the fluid chamber may adopt any other shape which can generate angular momentum in the burst of working fluid received by the fluid chamber. For example, the cross-section of the fluid chamber may be oval, elliptical, or polygonal.

The diameter of the fluid chamber is preferably in the range from 2 to 6.5 mm and in a preferred embodiment is around 4 mm.

An outlet port from the fluid chamber is preferably located on the longitudinal axis of the fluid chamber, and thus orthogonal to the inlet of the fluid chamber. The fluid outlet of the nozzle is preferably in axial alignment with the outlet port of the fluid chamber. The channel extending between the outlet port of the fluid chamber and the fluid outlet of the nozzle is preferably cylindrical in shape, and preferably has a diameter which is smaller than the diameter of the fluid chamber.

The diameter of the channel is preferably in the range from 1.5 to 3 mm, and in a preferred embodiment is around 2 mm. The transition between the fluid chamber and the channel may be tapered and/or stepped; in a preferred embodiment the outlet port is frustoconical in shape, tapering inwardly in a direction extending from the fluid chamber to the channel.

The fluid outlet of the nozzle preferably has a diameter which is smaller than the diameter of the channel. The fluid outlet preferably has a diameter in the range from 0.5 to 1.5 mm, and in a preferred embodiment is around 0.7 mm. The transition between the channel and the fluid outlet may be tapered and/or stepped; in a preferred embodiment the transition is frustoconical in shape, tapering inwardly in a direction extending from the channel to the fluid outlet. The longitudinal axis of the fluid chamber preferably passes through the fluid outlet of the nozzle, and so the longitudinal axis of the fluid chamber may be referred to as a nozzle axis on which the fluid chamber and the channel are centered.

The nozzle and the fluid conduit preferably form part of a fluid delivery system. The fluid delivery system is preferably configured to deliver working fluid to the inlet of the fluid chamber at a static pressure in the range from 3 to 10 bar. The fluid delivery system preferably comprises a pump and a control circuit for actuating the pump to eject a burst of working fluid towards the nozzle. As mentioned above, the volume of each burst of working fluid which is generated by the fluid delivery system is preferably less than 1 ml, more preferably less than 0.5 ml. In a preferred embodiment, the volume of the burst of working fluid generated by the fluid delivery system is in the range from 0.1 to 0.4 ml, and is preferably around 0.25 ml.

As the nozzle is moved between adjacent teeth of the user, the user may depress a button of a user interface provided on a handle of the appliance to actuate the pump to cause a burst of working fluid to be ejected from the nozzle. Alternatively, the appliance may be configured to actuate the delivery of working fluid to the teeth of the user automatically depending on the magnitude of an output from a sensor for detecting that the nozzle is located within an interproximal gap. For example, the sensor may be in the form of a light detector, such a camera or a light sensor, for receiving light, such a visible light or infrared light, reflected from a user's teeth. As another alternative, the appliance may be configured to actuate the delivery of working fluid to the teeth of the user automatically at a fixed frequency, for example between 0.5 and 5 Hz. The pump is preferably a positive displacement pump, such as a piston pump or a diaphragm pump. A hydraulic accumulator may be provided between the pump and the nozzle for storing working fluid at a pressure in the range from 3 to 10 bar. In this case, the fluid delivery system may comprises a valve, such as a solenoid valve, located downstream from the accumulator, and the control circuit may be configured to change the position of the valve from a closed position to an open position to release working fluid from the accumulator.

The nozzle may be moveable relative to a handle of the appliance. The nozzle is preferably moveable relative to the handle in a direction which extends generally parallel to or generally along the nozzle axis. The nozzle is preferably biased for movement relative to the handle in such a direction that the nozzle is urged against a user's teeth during use of the appliance. The fluid conduit is preferably moveable with the nozzle.

The nozzle may be connected to an arm, and that arm may be biased for movement relative to the handle in a direction which urges the nozzle against a user's teeth during use of the appliance. For example, the arm may be urged to move in that direction by a resilient member which engages the arm. Alternatively, the arm may be deformed elastically in such a manner that relaxation of the arm urges the nozzle against the user's teeth.

In a preferred embodiment, the fluid conduit is biased for movement relative to the handle in a direction which urges the nozzle against a user's teeth during use of the appliance. This fluid conduit may thus serve to bias the nozzle for movement relative to the handle in such a direction that the nozzle is urged against a user's teeth during use of the appliance. The fluid conduit may be moveable relative to the handle in one of a number of different ways. For example, the fluid conduit may be slidable, pivotable, rotatable or otherwise translatable relative to the handle. Alternatively, the fluid conduit may be extendable or expandable.

In a preferred example, the nozzle is moveable relative to the handle about an axis. The nozzle is preferably pivotable about the axis. This axis is preferably substantially orthogonal to the longitudinal axis of the handle. The axis is preferably angled to the nozzle axis, and is more preferably substantially orthogonal to the nozzle axis.

The fluid conduit preferably has a rigidity which is such that the fluid conduit does not deform, bend or kink as the fluid conduit moves with the nozzle relative to the handle. The fluid conduit is preferably formed from one of metallic and plastics material.

The nozzle is preferably biased for movement relative to the handle by a resilient member. The resilient member may engage a component to which the nozzle is connected. For example, the nozzle may be connected to a support for supporting the nozzle, and the support may be arranged to be moveable relative to the handle. The support may be biased for movement relative to the handle. As the support moves relative to the handle, the nozzle and the fluid conduit may move relative to the handle, preferably about an axis. Alternatively, the resilient member may engage the fluid conduit. The resilient member preferably exerts a force on the fluid conduit, or the support, which is of a sufficient magnitude to allow the nozzle to move, against the biasing force of the resilient member, as it is pressed against the user's teeth, and without exerting an excessive force on the teeth which is uncomfortable for the user.

In a preferred embodiment, the resilient member forms a part of the fluid delivery system, and is preferably in the form of a resilient section of the fluid conduit which is connected to the nozzle. That resilient section of the fluid conduit may be twisted, bent, compressed or otherwise deformed so as to exert a force on the nozzle which urges it to move relative to the handle against a user's teeth during use of the appliance.

Thus, the fluid delivery system may comprise a nozzle from which the burst of working fluid is delivered to the teeth of a user, and a fluid conduit having a relatively rigid section which is pivotable about an axis, and a relatively flexible, resilient section for urging the nozzle, and the relatively rigid section of the fluid conduit, to pivot about the axis in a direction which urges the nozzle against a user's teeth during use of the appliance. Alternatively, the sections of the fluid conduit may be provided by discrete connected components.

The appliance preferably comprises a cleaning tool which is detachably connected to the handle. The fluid delivery system may thus comprise a cleaning tool conduit system and a handle conduit system. The handle conduit system preferably comprises a fluid inlet port for receiving working fluid from a fluid outlet port of a fluid reservoir. The handle conduit system comprises a plurality of conduits for conveying working fluid between the fluid inlet port, the pump and a fluid outlet port of the handle. The cleaning tool conduit system preferably comprises a fluid inlet port for receiving a burst of working fluid from the handle fluid outlet port, the nozzle, and the fluid conduit.

The appliance preferably comprises a head, and a stem extending between the head and the handle. The nozzle preferably protrudes outwardly from, and is moveable relative to, the head. The nozzle is preferably biased for movement relative to the head in a direction which extends away from the head. The nozzle is preferably moveable between a distal position and a proximal position relative to the head. The nozzle is preferably biased for movement towards the distal position.

To facilitate the movement of the nozzle along the teeth of user during use of the appliance, the head preferably comprises means for engaging the teeth of the user, with the nozzle being moveable relative to the engaging means as it moves between its distal and proximal positions. For user comfort, the engaging means may be formed from resilient or elastomeric material. The engaging means may have a substantially flat upper surface, a curved upper surface, or a stepped upper surface. For example, the engaging means may have a concave upper surface. When the nozzle is in its distal position relative to the head, the tip of the nozzle preferably protrudes outwardly beyond at least some of the engaging means so that, when the nozzle is pressed against a user's teeth, the nozzle moves away from the distal position and towards the proximal position.

The appliance may be in the form of a dedicated interproximal cleaning appliance for cleaning between the gaps in the user's teeth. For such an appliance, the engaging means may comprise a single resilient member which surrounds the nozzle. Alternatively, the engaging means may comprise a plurality of resilient members arranged adjacent to the nozzle. The resilient members may be located on opposite sides or ends of the head, or arranged about the nozzle. For example, the resilient members may be arranged circumferentially about the nozzle. The resilient member(s) may be formed from elastomeric material.

Alternatively, the appliance may be in the form of a toothbrush which has the additional function of improved interproximal cleaning through the emission of a burst of working fluid into the interproximal gap. Where the appliance is in the form of a toothbrush, the engaging means preferably comprises a plurality of bristles. The bristles are preferably arranged around the nozzle, and may be arranged circumferentially about the nozzle.

The plurality of bristles may be attached to a static section of the head, which section is not moveable relative to the handle. Alternatively, or additionally, a plurality of bristles may be attached to a moveable section of the head, which section is moveable relative to the handle. In a preferred embodiment, the appliance comprises a brush unit comprising a bristle carrier and a plurality of bristles mounted on the bristle carrier, with the bristle carrier being moveable relative to the handle. The nozzle is preferably biased for movement relative to the brush unit in a direction extending away from the brush unit.

In addition to the movement of the nozzle relative to the brush unit, the brush unit is preferably moveable relative to the nozzle. The movement of the brush unit relative to the nozzle, to enable the ends of the bristles to be swept over the surfaces of the teeth of the user, may thus be independent from the movement of the nozzle relative to the handle. The bristle carrier may translate, rotate, pivot or vibrate relative to the nozzle.

The working fluid is preferably a liquid working fluid, and is preferably water. The appliance preferably comprises a fluid reservoir for storing working fluid, and from which working fluid is supplied to the fluid delivery system. The handle of the appliance may comprise the fluid reservoir. For example, the fluid reservoir may be fully contained within a body of the handle. Alternatively, an external wall of the handle may at least partially delimit the fluid reservoir. At least part of that external wall may be transparent to allow a user to see the volume of working fluid contained within the fluid reservoir. Alternatively, the fluid reservoir may be housed within the stem. As above, an external wall of the stem may at least partially delimit the fluid reservoir, and at least part of that external wall may be transparent to allow a user to see the volume of working fluid contained within the fluid reservoir. As an alternative to housing the fluid reservoir within the stem, the fluid reservoir may be connected to the stem so as to be located externally of the stem. This can allow the fluid reservoir to be detached from the stem for replenishment or replacement as required. Alternatively, the fluid reservoir may be partially delimited by an external wall which is connected to the stem. Again, at least part of that external wall may be transparent to allow a user to see the volume of working fluid contained within the fluid reservoir. To maximize the capacity of the fluid reservoir and to provide for a relatively even weight distribution about the longitudinal axis of the appliance, the fluid reservoir preferably extends about, or surrounds, the stem.

As mentioned above, the cleaning tool is preferably detachably connected to the handle. This can allow a handle to be provided with a set of similar cleaning tools, each with a respective different identifier for use by a different user. This can also allow a handle to be provided with a set of dissimilar cleaning tools. For example, the set of cleaning tools may be selected from two or more of a first type of cleaning tool with a nozzle and a moveable brush unit, a second type of cleaning tool with a nozzle and a static brush unit, a third type of cleaning tool with a nozzle and no bristles, and a fourth type of cleaning tool with a moveable brush unit and no nozzle. A number of respective different cleaning tools of the same type may also be provided, for example, of the first type of cleaning tool, with bristles having a respective different stiffness, or with nozzles having respective different fluid outlet sizes.

The appliance is preferably a handheld appliance which includes all of the aforementioned components of the appliance.

The cleaning tools may be sold as stand-alone items, for example as spare parts or as alternative cleaning tools for use with an existing handle.

In a second aspect the present invention provides a cleaning tool for a dental cleaning appliance comprising a handle to which the cleaning tool is detachably connectable, the cleaning tool comprising a stem; and a cleaning tool conduit system comprising a nozzle for delivering a burst of working fluid to the teeth of a user, and a fluid conduit for conveying working fluid to the nozzle, wherein the nozzle comprises a fluid chamber extending about a longitudinal axis and a channel for conveying working fluid from the fluid chamber to a fluid outlet from the nozzle, the fluid chamber comprising a fluid inlet for conveying working fluid into the fluid chamber at an angle to the longitudinal axis.

Features described above in connection with the first aspect of the invention are equally applicable to the second aspect of the invention, and vice versa.

