Drive system

The present invention provides a drive system having particular utility in an electric toothbrush, the drive system comprising a coupling (14) which is connectable between a drive source (12) and a brush head (16), the coupling being adapted to impart first and second independent brushing motions to the head.

FIELD OF THE INVENTION

This invention relates to a drive system, and in particular a drive system which is adapted to provide simultaneous and/or sequential drive in two separate directions, for example to a brush head or the like, in particular as part of a handheld electric toothbrush, and which facilitates the ready replacement of various components of the drive system and/or brush head by the end user.

BACKGROUND OF THE INVENTION

It is often desirable, when using tools such as brushes or the like, to mechanise the operation of same, both from a labour saving point of view, and often to improve the performance of such tools by increasing the speed or optimising a particular movement of same. Such is the case, for example, with an electric toothbrush, mixer, polishers/buffer or the like. However, in mechanising the operation of such tools, it is often necessary to limit the type of movement that the tool or tool head can undergo, in particular to keep the overall size, weight and complexity of the device within reason, in order to be practical for everyday use as a handheld and self contained tool. This is particularly evident in the field of electric toothbrushes, which can provide improved cleaning capabilities, but usually have a relatively limited range of movement at the brush head, in order to satisfy the above mentioned criteria.

The applicants International patent application WO2008/125269 discloses a toothbrush, in particular a mechanical toothbrush more commonly known as an electric toothbrush, which includes a spherical brush head which is capable of undergoing at least first and second independent brushing motions in order to improve the overall brushing effectiveness.

A number of embodiments are disclosed which detail various methods of delivering the first and second independent brushing motions to the head, and which incorporate different drive mechanisms to transmit motion to the bristled head of the brush. However, as with any toothbrush, whether mechanically/electrically or manually operated, the bristle on the head will in time become worn or significantly deformed to the point of requiring replacement. In order to prolong the working life of the head, and in particular the drive mechanism, it is preferable if the drive mechanism can be substantially sealed from the ingress of water and other contaminants such as toothpaste, while optionally including and retaining a lubricant about the drive mechanism. In addition, for a product such as an electric toothbrush it is important that the head of the brush can be replaced, while retaining the body, which includes the motor, control circuitry, and other aspects of the brush. It is also important that the head can be replaced quickly and easily by the end user. In addition to providing for the quick and easy replacement of the head by the user, there are other issues to be addressed in designing and manufacturing an electric toothbrush. In particular the cost and complexity of manufacture must be kept relatively low in order to provide an economically viable product, for example by designing the product for convenience of assembly during production. As the toothbrush of WO2008/125269 has a more complex drive mechanism than a conventional electric toothbrush, these are greater challenges to overcome.

It is therefore an object of the present invention to overcome some of the above-mentioned problems of the prior art.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided A drive system for connection to a drive source, the drive system comprising a head; and a coupling connectable between the drive source and the head and operable to impart at least first and second independent motions to the head.

Preferably, the coupling is operable to impart continuous rotary motion to the head for both the first and the second motions.

Preferably, the coupling is adapted to rotate the head about a first axis as the first motion and independently and/or simultaneously about a second axis as the second motion.

Preferably, the first and second axes are substantially orthogonal to one another.

Preferably, the first and second axes pass through the centre of the head.

Preferably, the coupling comprises a first pulley and a second pulley, and a belt extending between the first and second pulleys, the first pulley arranged to be driven by the drive source and the second pulley arranged to drive the head.

Preferably, the coupling comprises an elongate rigid support extending between the first and second pulleys and at a free end of which support the head is mounted.

Preferably, the belt extends substantially longitudinally of the support.

Preferably, the support is rotatable by the drive source about a longitudinal axis of the support.

Preferably, the support forms a guide for the belt.

Preferably, the head comprises a rotatable element to which the coupling is arranged to impart the first and second independent motions.

Preferably, the second pulley is formed integrally with the rotatable element.

Preferably, the belt comprises a toothed belt.

Preferably, the free end of the support comprises a tab having an aperture therein through which two halves of the rotatable element are secured to one another.

Preferably, the tab comprises a ring and each half of the rotatable element forms a seal with the ring when secured thereto.

Preferably, the head comprises an array of bristles extending outwardly from the rotatable element.

Preferably, the bristles are provided on each half of the rotatable element and are oriented, at or adjacent an interface between the halves, to converge in order to provide continuity to a cleaning surface defined by the bristles.

Preferably, the drive system comprises the drive source, and wherein the drive source comprises a pair of concentric drive shafts, a first shaft arranged to drive the first pulley, and a second shaft arranged to effect rotation of the support.

Preferably, the drive source comprises a clutch displaceable between an engaged and a disengaged state, in the engaged state enabling synchronous rotation of the first and second shafts, and in the disengaged state enabling independent rotation of the first shaft.

Preferably, the drive system comprises a sleeve surrounding at least a portion of the support and within which sleeve the support is rotatable about a longitudinal axis of the sleeve.

Preferably, the coupling is releasably engageable with the drive source.

According to a second aspect of the present invention there is provided a handheld device comprising a drive system according to the first aspect of the invention, and a body housing the drive source; wherein the drive system is releasably mountable to the body in operative engagement with the drive source.

Preferably, the device comprises a transducer disposed internally of the body and operable to transfer drive from the drive source to the first pulley and to effect rotation of the support relative to the body.

Preferably, the transducer is rotatable within the body by the drive source in order to impart the second independent motion.

Preferably, the drive system is insertable into the body and engagable with the transducer by means of the longitudinal insertion of a free end of the coupling into the body.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring now toFIGS. 1 to 4of the accompanying drawings there is illustrated a first embodiment of a drive system according to the present invention, generally indicated as10, which is operable to impart first and second independent motions, preferably continuous rotation, to a rotatable element of the drive system, and which may therefore find utility in an electric toothbrush or the like. It will however be appreciated that alternative uses of the drive system10may be employed, for example for use as a polisher, a grinder, a drill, a mixer/agitator or any other suitable application.

The drive system10is connectible with, and optionally comprises, a drive source12which may comprise or be connectable with an electric/hydraulic/mechanical drive means as will be described hereinafter in order to provide the motive power to the drive system10. The system10further comprises a coupling14extending between the drive source12, and a head16mounted at the opposed end of the coupling14. The head16defines the working end of the drive system10, as will be described in detail hereinafter, and may for example comprise a brush head having an array of bristles thereon, in order to for example to effect cleaning/scrubbing or the like.

Returning to the drive source12, there is comprised a motor18which in the present embodiment is in the form of an electric motor which is arranged to drive, via a clutch20, a transducer in the form of a gear housing22. Extending between the clutch20and the gear housing22are concentric first and second shafts (not shown). The first shaft projects into a window24in the gear housing22and has a first bevel gear26mounted on the free end thereof. This first bevel gear26meshes with a second bevel gear30secured to the exterior of the gear housing22. Mounting co-axially with the second bevelled gear30, on the interior of the gear housing22, is a first pulley or cog in the form of a toothed pinion (not visible in the drawings), which is therefore directly driven by the second bevel gear30.

Extending from the gear housing22, and forming part of the coupling14, is a support32in the form of a rigid shaft at the opposed free end at which is mounted the head16. The coupling14further comprises an endless belt34which passes around the first pulley/gear pinion (not shown) within the gear housing22, and exits the gear housing22to extend along the support32and into the head16, before returning from the head16back along the support32to re-enter the gear housing22. In the embodiment illustrated the support32defines a pair of recessed channels36therein which are shaped and dimensioned to house the belt34. Returning to the drive source12, there is comprised a motor18which in the present embodiment is in the form of an electric motor which is arranged to drive, via a clutch20, a transducer in the form of a gear housing22. Extending between the clutch20and the gear housing22are concentric first and second shafts (not shown). The first shaft projects into a window24in the gear housing22and has a first bevel gear26mounted on the free end thereof. This first bevel gear26meshes with a second bevel gear30secured to the exterior of the gear housing22. Mounting co-axially with the second bevelled gear30, on the interior of the gear housing22, is a first pulley or cog in the form of a toothed pinion (not visible in the drawings), which is therefore directly driven by the second bevel gear30.

Turning then to the head16, the support32extends to form a tab38at the free end thereof, which in use is located at the interior of the head16, and forms the main mounting and bearing by which the head16is secured to the drive system10. The head16further comprises a rotatable element40, which in the embodiment illustrated is substantially spherical, and is comprised of a pair of hemispherical halves42which are secured to one another through the tab38, via a spindle44. The spindle44in the embodiment illustrated is permanently fixed into one of the halves42, and the exposed portion of the spindle44is threaded for engaging with the opposed half42as shown inFIG. 2. The spindle44passes through a central aperture46in the tab38, and is then threaded into the opposed half42. Thus the rotatable element40, in use, is spherical in shape and rotatably mounted on the tab38.

As the belt34reaches the head16it passes through a collar48which circumscribes both the support32and the two sides of the belt34housed in the channels36, before the belt34separates outwardly to pass around an exterior surface of the rotatable element40. The rotatable element40thus acts as a second pulley/gear pinion around which the belt34passes, thereby enabling the belt34to impart motion in the form of continuous rotation to the rotatable element40. This rotation comprises a first independent motion in the form of continuous rotation about a first axis defined by the spindle44.

In order to improve the transfer of power from the belt34to the rotatable element40, in particular when the rotatable element40is under load, it is preferable that the belt34comprises a toothed belt and, although not illustrated, the belt34may have various cross sections such as a conventional V-belt profile or the like. The rotatable element40is thus provided with a corresponding circumferential array of teeth50formed integrally within an outer surface of the two halves42of the rotatable element40. A portion of the teeth50are formed in each half42of the rotatable element40and adjacent the contacting faces of the halves42. The teeth50thus define a track or second pulley on the surface of the rotatable element40around which the belt34passes.

In order to prevent slippage of the belt34over the teeth50, the head16preferably comprises a guide52, which extends from the collar48and circumscribes the belt34, thus maintaining the belt34in driving engagement with the teeth50. The belt34may be formed from any suitable material, and is preferably formed in conventional fashion from fibre reinforced rubber, providing both the necessary strength, and relatively quiet operation, which is desirable when the system10is to be used in applications such as an electric toothbrush. In use it is likely that the support32and the sections of the belt34located in the channels36would be surrounding by a protective covering such as a plastic sleeve or the like.

In the embodiment illustrated the head16is also preferably provided with a pair of guards54, one located on either side of the belt34and circumscribing the respective hemisphere half42. Each guard54is positioned in close proximity to the interface between the belt34and the teeth50in order to prevent the ingress of any item to the interface, which could become entangled with the belt34and/or cause damage or slippage over the teeth50. For example in the embodiment illustrated the rotatable element40is in the form of a brush head and is provided with an array of bristles56thereon, in order to effect a brushing action to allow the drive system10to function as an electric toothbrush. The guards54thus ensure that, in particular during use, the bristles56do not become entrained between the belt34and the teeth50. Each of the guards54is secured to the collar48, although it will be appreciated that any other means of mounting the guards54to the head16may be employed.

Thus as described above the belt34is used to impart a first independent driving motion to the head16, and in particular the rotatable element40. This first independent driving motion is continuous rotation, in either direction, about the axis defined by the spindle44. However the drive system10is adapted to impart a second independent motion to the head16, and again in particular the rotatable element40. The first motion is achieved by driving the first shaft (not shown), which in turn effects driving of the belt34via the bevel gears26,30. However, the clutch20is operable to effect a synchronous driving of the first and second shafts. This results in the gear housing22being rotated about an axis defined by a longitudinally axis of the support32. This rotation of the gear housing22thus effects rotation of both the support32connected thereto, and as a result rotation of the head16connected to the support32. This gives rise to a second independent motion, in the form of a rotational motion, and preferably a continuous rotational motion about an axis defined by a longitudinal axis of the support32. By driving the first and second shafts (not shown) synchronously, the first bevel gear26will remain stationary relative to the second bevel gear30which is also rotating at the same speed as a result of the rotation of the gear housing22. This ensures that as the second brushing motion is being implemented the belt34remains stationary, thus ensuring that the first brushing motion remains independent of the second brushing motion. It should however be understood that the first and second motions imparted to the rotatable element40could be applied simultaneously, by rotating the housing22and driving the belt34at the same time to achieve variable patterns of movement at the head16.

It should however be understood that there are various means by which the two above mentioned independent motions may be achieved. For example, rather than having two concentric shafts extending from the clutch20into the gear housing22, a single shaft (not shown) could be used, which would extend from the clutch20into the gear housing22and be connected to the first bevel gear26. The clutch20is then adapted to selectively lock the gear housing22relative to the clutch20, or to release it for rotation relative thereto. This locking/releasing may be achieved by any suitable means, for example a switch actuated mechanical lock (not shown) which can slide out of the clutch20to engage and lock the gear housing22, and which can then be retracted in order to release the gear housing22. In order to impart the first motion to the head16the gear housing22is locked to the clutch20. As a result when the single shaft extending from the clutch20to the first bevel gear26is driven the gear housing22cannot move and so the drive is transmitted directly to the first bevel gear26. With this single shaft arrangement a bearing (not shown) or the like is provided between the shaft and the gear housing22in order to allow the shaft to turn freely despite the gear housing22being locked in place. As described above this will result in the belt34being driven in order to impart the first brushing motion to the head16. To impart the second independent motion to the head16the gear housing22is disengaged or unlocked from the clutch20, for example as described above by releasing the switch actuated mechanical lock. As a result when the single shaft is driven the entire gear housing22, and thus the coupling14, will rotate to impart the second independent motion to the head16. The bevel gear26is not turned within the gear housing22as the drive from the shaft will take the path of least resistance to the head16, which is through rotation of the entire gear housing22which presents less resistance than driving the belt34.

Referring now toFIGS. 4 to 9there is illustrated a second embodiment of a drive system according to the present invention, generally indicated as110, again for use in a hand held device such as an electric toothbrush or the like. In this second embodiment like components have been accorded like reference numerals, and unless otherwise stated, perform a like function. The system110is adapted, as with the first embodiment, to impart first and second independent motions to a head116of the toothbrush. It will of course be appreciated that the head116may be substituted by any other suitable attachment if the system110is to be employed in a device other than an electric toothbrush.

The head116, in the second embodiment, is again substantially spherical and although not illustrated is covered in its entirety by outwardly extending bristles (not shown). The detailed operation of the system110, as a component part of a toothbrush or the like, will be described once the configuration and operation of the drive system110has been explained.

Thus referring in particular toFIGS. 6 to 9the drive system110comprises a coupling114in the form of a hollow casing114comprising first and second free ends60,61connected by a support in the form of a hollow central portion132extending therebetween. It can be seen fromFIGS. 7 and 8that the first and second ends60,61are circular in profile while the central portion132is substantially elongate. FromFIG. 9it can be seen that the entire casing114is of a uniform thickness and is relatively narrow. For example if used in an electric toothbrush the casing114may be less than 5 mm in thickness. The casing114may be formed from any suitable material and in any suitable manner, and for example is preferably moulded from a plastic material or the like.

Referring toFIG. 7the system110is shown in section. Located within the casing114is a drive assembly comprising a first toothed pulley or pinion62seated in the first end60and a second toothed pulley or pinion63seated in the second end61. Extending between and around each of the pulleys62,63is a toothed belt134which forms part of the drive assembly and is preferably formed from a material such as reinforced rubber or the like. An aperture64in either end60,61of the casing114facilitates external access to a corresponding aperture65in each of the pulleys62,63. Thus it will be appreciated that if the first pulley62is rotated from the exterior, for example by means of a drive shaft passed through the aperture64in the casing114, this rotation will be transmitted by the belt134to the second pulley63. This drive can then be transmitted to the head116which may be secured to the second pulley63via an axle66passing outwardly through the apertures65on the casing114at the second end61. The belt134is preferably narrow in width, for example 1 to 2 mm in width, in order to facilitate the narrow width of the casing114. It is preferable, as the belt134will undergo wear during use, that the transition between both the first and second ends60,61and the central portion132, on the interior of the casing114, is curved in order to minimise wear on the belt134at these points. It is also envisaged that a lubricant or the like may be provided on the interior of the casing114in order to minimise wear of the belt134and generally improve the operation thereof. However, as described in more detail below, the casing114, with the head116mounted thereon, is designed to be user replaceable, in order to allow a new casing114and head116to be fitted to a toothbrush once the original head116becomes worn, or in the event of damage such as a break in the belt134.

The system110further comprises a sleeve67located co-axially about the central portion132of the casing114. The sleeve67is cylindrical in form and is dimensioned to permit the casing114to rotate within the sleeve67about a longitudinal axis thereof. To this end bearings or bushings (not shown) may be provided between the sleeve67and the exterior of the casing114. The sleeve67may therefore be held immobile while the casing114can be rotated therein. Again the sleeve67may be formed from any suitable material, preferably a plastic.

Returning now in particular toFIGS. 4 and 5the operation of the drive system110in combination with the electric toothbrush will be described in detail. Thus the toothbrush comprises a relatively conventional body68, which will house a drive source (not shown) in the form of an electric motor or the like. The body68will also include a compartment or space for a power source such as a battery, although equally the toothbrush could be mains powered. Similarly control circuitry or the like will be housed within the body68. As with a conventional electric toothbrush, as well as housing all of the above components, the body68serves as a handle by which the toothbrush may be held and manipulated.

The body68further comprises a nose69defined by a pair of hinged access panels70each of which is mounted on a hinge71in order to allow one or both of the panels70to be hinged outwardly in a clam shell arrangement. The panels70may be hinged between open and closed positions by the user, in order to expose or conceal the interior of the toothbrush. Located within the interior space defined by the pair of panels70is a transducer122which is operable, as will be described hereinafter, to transmit to the head116, via the casing114, first and second independent motions in similar fashion to the transducer of the first embodiment. The transducer122defines a substantially circular recess72which is shaped and dimensioned to receive the first end60of the casing114therein. The recess72has a narrow or restricted neck73which will prevent the axial withdrawal of the first end60from the recess72once positioned therein. It should also be appreciated that some form of releasable locking mechanism (not shown) could be provided to further secure the first end60of the casing114within the recess72.

The transducer122comprises a drive shaft74projecting upwardly into the recess72, which drive shaft74is located and dimensioned to pass through the aperture64in the first end60in order to engage with the first pulley62. The drive shaft74can be driven by the electric motor (not shown) in order to rotate in the direction indicated by arrow A, which gives rise to the first independent brushing motion. Controls (not shown) for the toothbrush may also be used to reverse the direction of rotation of the drive shaft74. The electric motor is also operable to effect rotation of the entire transducer122within the nose69about an axis corresponding with a longitudinal access of the sleeve67when the system110is mounted to the toothbrush, in a direction indicated by the arrow B. This gives rise to the second independent brushing motion. Again controls (not shown) for the toothbrush may be used to reverse the direction of rotation of the transducer122.

Turning then to the operation of the toothbrush, the access panels70are initially hinged into the open position in order to provide access to the transducer122. The casing114, with the head116secured at the second end61, is then seated with the first end60located within the recess72of the transducer122. This results in the drive shaft74being seated into the aperture64in the first end60and thus engaging the first pulley62. The access panels70are then hinged back into the closed position with an opening75defined between the interface of the panels70accommodating the sleeve67. The opening75is dimensioned to grip the exterior of the sleeve67when the panels70are in the closed position, in order to immobilise the sleeve67with respect to the body68of the toothbrush. To this end the opening75may be provided with a lip or the like in order to increase the surface area in contact with the sleeve67. Similarly the opening75could be lined with a material such as rubber or the like in order to increase the friction between the opening75and the exterior of the sleeve67, while also providing a seal to the ingress of moisture or the like to the body68. Alternatively the sleeve67, at the point at which the opening75engages same, could be provided with indentations while the opening75is provided with corresponding projections or teeth to engage the indentations. Locking means (not shown) may be provided in order to lock the access panels70in the closed position. Such locking means could take the form of mechanical, electrical or magnetic looking means. Once the access panels70have been hinged back into the closed position the system110is secured in place as an integral part of the toothbrush. The toothbrush is then ready for operation by the end user.

Controls (not shown) on the toothbrush may then be used to drive the transducer122as described above. By operating the drive shaft74without rotating the transducer122the first pulley62will be driven, thereby driving the second pulley63via the belt134. This will drive the bristled head116as a first independent motion in the form of rotary motion about a first axis corresponding with the axle66. In order to effect the second independent motion, through operation of the toothbrush controls (not shown), the entire transducer122is rotated in the direction of arrow B by the electric motor. As the sleeve67is immobilised by the access panels70, the casing114will then rotate within the sleeve67about a longitudinal axis of the sleeve67. This will thus impart a second independent motion to the head116around a second axis corresponding to a longitudinal access of the sleeve67. In the embodiment illustrated the shaft74is driven from the electric motor through a set of bevel gears (not shown) located at the rear of the transducer122as seen inFIG. 5. Thus during rotation of the transducer122to achieve the second independent motion, it is necessary to simultaneously drive the shaft74at a speed which will ensure that the bevel gear (not shown) on the shaft74keeps pace with the rotation of the bevel gear (not shown) connected to the electric motor, thereby ensuring that relative to one another there is no movement between the two bevel gears and no motion will be imparted to the first pulley62. As a result the head116will rotate about the longitudinal axis of the casing114without rotating about the axle66.

It should be understood that the sleeve67is not an essential element of the invention, and could be omitted while maintaining the above functionality. However, the rotating casing114would then be exposed, and may cause discomfort to the user, as the rotating casing114would contact the users' lips and/or teeth during operation of the toothbrush. The sleeve67is preferably a user replaceable element of the system110, preferably in combination with the casing114.

It should also be appreciated that the drive assembly as defined by the first and second pulleys62,63and the belt134could be replaced with any other suitable alternative. For example, the first and second pulleys62,63could be replaced with first and second bevelled gears, with a shaft extending longitudinally through the central portion132between the gears. A suitable bevelled gear could be provided on either end of the shaft in order to mesh with the first and second gears. It is envisaged, in particular when the system110is used with an electric toothbrush, that the head116will be permanently secured to the casing114and thus not removable by the end user. It is preferably that the combined casing114, including the internal drive assembly, and the head116be replaced as a single unit.

Referring now toFIGS. 10 to 14there is illustrated a further alternative embodiment of a drive system according to the present invention, generally indicated as210, for use with an electric toothbrush (not shown) or the like. In this embodiment like components have again been accorded like reference numerals, and unless otherwise stated perform a like function. The system210comprises a coupling214, which is operable, in use, to impart first and second independent motions to a head216, which in the embodiment illustrated is in the form of a bristled head for use as an electric toothbrush. The coupling214, as with the previous embodiment, is adapted to be releasably engaged with the toothbrush in order to enable user replacement of the coupling214and brush head216, for example when the bristles become worn.

The coupling214comprises a first end260which in use permits drive to be transferred from the main body of the toothbrush to the coupling214, and therefore on to head216. The coupling214further comprises an opposed second end261, which comprises a tab in the form of an open ring261into which, in use, two hemispherical halves241of the head216are seated and retained. Extending between the first and second ends260,261is a support in the form of a hollow cylindrical tube232, which in the embodiment illustrated is moulded, along with the first and second ends260,261, as a single unit. Passing through the hollow tube232is a toothed belt234(shown schematically by a dashed line), which is engaged about first and second pulleys262,263, located, respectively, in the first and second free ends260,261.

Referring to the second end261, as most clearly shown inFIG. 14, the belt234exits the hollow tube232via a narrow opening80, which is provided in the form of a slot formed in the inner wall of the ring261. It can be seen that a rim81formed on either side of the ring261is provided with a step82for receiving the respective hemispherical half241of the brush head216. In this way, in particular as seen inFIG. 14, each half241of the head216forms an effective seal with the rim81of the ring261, thereby preventing the ingress of water/toothpaste or other contaminants to the interior of the ring261where the belt234is housed. The ring81and step82also act as a bearing for each hemispherical half241of the head216, allowing the head216to freely rotate when mounted to the ring261. The two halves241of the head216are secured relative to one another by any suitable means, such that they will rotate in unison, thus effectively rendering the head216as a single sphere. The second pulley263is either sandwiched between the two halves of the head216, or may be formed integrally with one or both of the hemispherical halves. As the belt234passes around the second pulley263, it can then be used to drive the brush head216.

Referring now to the first end260, in particular as seen inFIG. 11, this is provided as an open ended cylinder having a mouth83from which partially projects a pair of drive gears84which are concentrically mounted on either side of the first pulley262, and are fixed thereto. In this way rotation of one or other of the drive gears84will effect the simultaneous rotation of the first pulley262. As the belt234is engaged around the first pulley262, rotation of the drive gears84will effect the displacement of the belt234and therefore rotation of the head216.

Referring now toFIG. 10the system210again comprises a transducer222, which is operable to impart the first and second independent motions to the head216via the coupling214. The transducer222comprises an inlet or socket272, which is dimensioned to slidingly receive, in a longitudinal direction, the first end260of the coupling214therein. The socket272and first end260are preferably provided with a key and corresponding keyway (not shown) in order to ensure the correct alignment between the coupling214and the transducer222. Mounted to the transducer222and accessible through the socket272, is a corresponding pair of drive gears85which, once the first end260is seated correctly within the socket272, will mesh with the drive gears84projecting from the mouth83of the first end260. The drive gears85are, in use, driven by a motor212provided as part of the toothbrush, which will thus effect, through the drive gears84and the belt234, the first independent motion of the head216.

The motor212is also adapted to effect the rotation of the entire transducer222, which will effect the rotation of the coupling214about a longitudinal axis thereof, in order to effect the second independent motion of the brush head216. It will be appreciated that these motions could be independently reversed, mixed, or programmed to occur in predetermined sequences, all through the transducer222.

In use the transducer222will be housed within a body (not shown) of the toothbrush, and is preferably positioned such that the open end of the socket272is located coterminous with a free end of the body of the toothbrush, such as to permit the coupling214to be quickly and easily inserted and removed from the toothbrush. Once inserted into the socket272, it is preferable that some form of locking means is engaged in order to prevent the accidental separation of the coupling214and transducer222. Thus the coupling214, carrying the brush head216, can be quickly and easily pressed into or pulled out of engagement with the body of the electric toothbrush, in order to allow quick and easy user replacement. No portion of the body needs to be opened or closed in order to effect this replacement.

The drive system10;110;210may comprise, particularly when being used as part of an electric toothbrush, a guard (not shown) covering a potion of the head16;116;216, for example in the form of a hemisphere surrounding half of the head. The guard (not shown) may be secured to the drive system10;110;210by any suitable means.

It will therefore be appreciated that the drive system10;110;210of the present invention allows two independent and/or simultaneous motions to be applied to a head such as a brush head16;116;216or the like with relatively simple components, and in an overall assembly which is relatively small in size to enable same to be used in a hand held and portable manner. The drive system10;110;210also enables the head16;116;216of the brush to be quickly and easily replaced by the end user. In addition the cost and complexity of manufacture of the system10;110;210will be relatively low in order to provide an economically viable product.