AU2015207937B2

AU2015207937B2 - Electric toothbrush attachment

Info

Publication number: AU2015207937B2
Application number: AU2015207937A
Authority: AU
Inventors: Craig Hills
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-03-17
Filing date: 2015-07-31
Publication date: 2017-03-30
Anticipated expiration: 2024-03-17
Also published as: AU2015207937A1

Abstract

An electric toothbrush includes a brush head that has a plurality of tooth engaging elements, such as bristles and polishers optionally arranged in alternating rows on the brush head. The brush head is mounted at the distal end of an elongate driven shaft connected through a universal joint to the drive shaft of a drive means typically located in the handle or body portion of the toothbrush so that the driven shaft is at a shallow angle to the line of the drive shaft. The driveable toothbrush attachment and the handle or body portion are separable modular units. A guard is mounted by and extends beyond the housing around the driven shaft and is located around part of one side of the brush head and along the length of the brush head so as to shield soft tissues of a user's mouth except from the exposed bristles of the brush head. The brush head is operable to slowly rotate (at say, between 60 and 240 rpm), about an axis substantially corresponding to the longitudinal axis of the drive shaft.

Description

1 2015207937 31 Μ 2015

ELECTRIC TOOTHBRUSH ATTACHMENT PRIOR APPLICATIONS

[0001] This is a divisional application of Application No. 2010202965 which, in turn, was a divisional of No. 2005222538, filed 14 July 2010 which, in turn, was a divisional of PCT/AU2004/000320, filed 17 March 2004 that claims priority from Australian patent application nos. 2003901241, 2003901242, 2003901243, 2003901244 all filed on 17 March 2003. The contents of those applications are incorporated herein by this cross reference.

FIELD OF INVENTION

[0002] This invention relates to a toothbrush attachment for electric toothbrushes and to electric toothbrushes including replaceable attachments. More particularly, this invention relates to electric toothbrushes with selectively attachable rotatable toothbrush heads and assemblies thereof in use.

BACKGROUND OF THE INVENTION

[0003] Electric toothbrushes are known as dental maintenance devices. The electric toothbrush typically includes a detachable shaft with a small head. The small head includes a brush mounted for oscillation about an axis transverse to the shaft. In these prior electric brushes, the brush is configured to move rapidly in a reciprocating arcuate motion and performs primarily as a gum massager, rather than an effective toothbrush capable of removing debris and/or plaque from the user’s teeth. Rotating electric toothbrushes have been proposed but are not known to be effective.

[0004] It is an object of the present invention to provide an attachment for a rotating electric toothbrush attachment which can be effective to brush and clean a user’s teeth. 2015207937 03 Mar 2017 2 [0005] It is a further preferred object of the present invention to provide a rotating electric toothbrush attachment which can be capable of use with minimal or no or reduced damage or irritation to gums.

SUMMARY OF THE INVENTION

[0006] The invention in a first aspect provides an electric toothbrush including: a drive arrangement including a grippable handle with a drive means mounted within the grippable handle, switch means for controlling operation of the drive means, and a drive shaft rotated about a drive axis by operation of the drive means; a housing releasably attachable to the drive arrangement, said housing having an elongated shape; an elongated driven shaft extending within the housing and operatively coupled to the drive shaft through a universal joint so that driven shaft extends at an acute angle to said drive shaft; a brush head located at a distal end of the driven shaft and having a head shaft coupled to the driven shaft so as to be rotated thereby in use about a brush head rotation axis coincident with a rotation axis of said driven shaft, said brush head having a plurality of tooth engaging bristles composed of soft polymer material arranged in separate bristle tufts with each said bristle tuft having multiple bristles, the bristle tufts projecting outwardly from the head shaft and being provided in multiple rows spaced peripherally about said head shaft, each said row of bristle tufts extending along the head shaft with the bristle tufts in each said row being staggered in position along the head shaft relative to the bristle tufts in an adjacent said row of said bristle tufts, wherein the drive arrangement includes a button or switch for switching the rotational direction of the brush head.

[0007] Preferably, the electric toothbrush also includes a guard for said brush head mounted to or forming part of said housing, located around part of one side of the brush head and along a full length of the brush head so as to shield soft 3 2015207937 03 Mar 2017 tissues of a user’s mouth except from the bristles exposed on the brush head at an opposite side to said guard.

[0008] Preferred features of the aforesaid aspect may be as defined in any one of claims 2 to 5 or 7 to 19 inclusive, the subject matter of same being included in the disclosure of this specification by this reference thereto.

[0009] According to another aspect of the invention, there is provided a replaceable toothbrush attachment to the electric toothbrush of the first aspect, said toothbrush attachment including: a housing releasabiy attachable to the electric toothbrush drive arrangement, the housing having an elongated shape extending in a direction at an acute angle to the drive axis of the drive shaft; an elongated driven shaft extending along and within the housing and, in use, operatively coupled to the drive shaft of the electric toothbrush drive arrangement through a universal joint so that the rotation of the drive shaft is transmitted to the driven shaft extending at the acute angle thereto; and a brush head located at a distal end of the driven shaft and having a head shaft drivingiy coupled to the driven shaft so as to be rotated thereby in use about a brush head rotation axis coincident with said driven shaft, the brush head having a plurality of tooth engaging bristles composed of soft polymer material arranged in separate bristle tufts with each said bristle tuft having multiple bristles, the bristle tufts projecting outwardly from the head shaft and being provided in multiple rows spaced peripherally about said head shaft, each said row of bristle tufts extending along the head shaft with the bristle tufts in each said row being staggered in position along the head shaft relative to the said bristle tufts in an adjacent said row of bristle tufts, wherein the brush head is configured so that its rotational direction can be switched by the button or switch of the drive arrangement.

[0010] Preferably, the aforesaid replaceable toothbrush attachment also includes a guard for said brush head mounted to or forming part of said housing, 4 2015207937 03 Mar 2017 located around part of one side of the brush head and along a full length of the brush head so as to shield soft tissues of a user’s mouth except from the bristles exposed on the brush head at an opposite side to the guard.

[0011] Preferably the housing has an elongated shape with releasable attachment means located at one end enabling attachment to the grippable handle at said acute angle. Conveniently the acute angle is about 60°.

[0012] Preferred features of the replaceable toothbrush attachment may be as defined in any of claims 2 to 16 inclusive as annexed hereto, the subject matter of these claims are included in the disclosure of this specification by this reference thereto.

[0013] Each bristle is preferably of about 1 mm diameter at its base where the tuft projects from the head shaft.

[0014] The brush head located at the distal end of the driven shaft is preferably manufactured separately from the driven shaft and is assembled thereto so as to be rotated thereby without being separable therefrom in use.

[0015] There is also described herein an electric toothbrush having a driveable toothbrush attachment including a brush head having a plurality of tooth engaging elements, such as bristles and polishers optionally arranged in alternating rows on the brush head, the brush head adapted to operably engage an elongate drive shaft for connection to drive means typically located in the handle or body portion of a toothbrush unit, the driveable toothbrush attachment and the handle or body portion being separate modular units, wherein the brush head is operable to slowly rotate (at say, between 60 and 240 rpm), about an axis substantially corresponding to the longitudinal axis of the drive shaft.

[0016] The drive shaft may be housed in an elongate sheath whereby the user’s soft buccal cavity tissue is not exposed to the rotating drive shaft. The 5 2015207937 31 Μ 2015 brush head may include a head shaft contiguous with the drive shaft. The head shaft may be engageable to the drive shaft. The head shaft may be integrally formed with the drive shaft. Preferably, the head shaft is non-releasably attachable to the drive shaft to reduce the possibility of the brush head separating from the drive shaft during use thereby posing a potential choking danger to the user.

[0017] The drive shaft may be flexible and may comprise a flexible metal wire or polymer rod. The drive shaft may comprise a metal or polymeric cable, optionally comprising a plurality of strands for increased strength and flexibility. Alternatively, the drive shaft may be rigid and may comprise a metal shaft or a polymeric shaft made from high strength material. The person skilled in the art will appreciate that the drive shaft may be made from any material found to be suitable in the corresponding component of driven toothbrushes of the prior art.

[0018] The driveable toothbrush attachment may include guard means to protect the soft tissue of the user’s buccal cavity. The guard means may include a cover located on one side of the brush head leaving the user’s teeth exposed on the other side to the tooth engaging elements. The guard means may be hinged, for example to the sheath so that the brush head may be more thoroughly cleaned. However, preferably, the guard means is non-releasably engaged to the attachment or to the sheath to reduce the dangerous possibility of the guard means becoming separated in the buccal cavity and thereby presenting a choking hazard.

[0019] The speed of the rotational motion of the brush head is preferably between 60 and 240 rpm. Preferably, the speed of the brush head is in the lowest third of this range, i.e. between 60 and 150 rpm and most preferably about 100 rpm. The slow rotational motion of the brush head advantageously improves the brushing action of the brush head and distinguishes the invention from prior art oscillating/vibrating brush heads which effectively operate as gum massagers, rather than effective toothbrushing devices. Also these slow speeds minimise or 6 2015207937 31 M2015 avoid gum damage if the rotational direction carries the brush elements from the distal or free ends of the teeth into contact with the gums. Higher speeds can cause centrifugal discharge of particulates. The tooth engaging elements may include a variety of different types of elements. Preferably, the tooth engaging elements comprise a plurality of bristles and a plurality of polishers. The bristles may be effective to brush the teeth and the polishers effective to clean and polish the teeth. The bristles and polishers may be located in alternating rows on the brush head. The alternating rows may be aligned along the length of the brush head. Preferably, the alternating rows are arranged parallel to the longitudinal axis of the brush head.

[0020] Preferably, the brush head includes a head shaft on which the tooth engaging elements are mounted. The cross-section of the head shaft may be uniform along its length. Alternatively, the cross-section of the head shaft may vary such that the head shaft is tapered at one or both ends to improve the comfort of the user. The brush head cross-section may be polygonal whereby the head shaft includes a plurality of elongate flat faces spaced radially from its longitudinal axis. The brush head cross-section may be hexagonal or octagonal. The alternating rows of bristles and polishers may extend along the elongate faces. This arrangement is advantageous for ease and cost of manufacture as each type of tooth engaging element may be mounted on each corresponding elongate face in a simplified process. The process for mounting the tooth engaging elements on the head shaft include forming apertures in the head shaft to receive the tooth engaging elements either by forming bores or, preferably, by forming the apertures in an injection moulding process, inserting the tooth engaging elements into the apertures and fusing the tooth engaging elements into place by heat welding, ultrasonic welding or other methods known to the skilled person in the art.

[0021] The basic toothbrush unit may include a handle housing a rechargeable battery source and an electric motor. Desirably, the attachment is releasably connectable to the existing unit via the attachment of the elongated 7 2015207937 03 Mar 2017 drive shaft and sheath to the existing unit. As the typical toothbrush electric motor available in the marketplace prior to this invention was a small high speed motor capable of running at speeds of 6000 rpm, the rotational speed must be modified by a gearing system to translate the high speed rotation of the electric motor to low speed rotation of the brush head. Alternatively, a slow speed electric motor may be employed.

[0022] One or more types of the tooth engaging elements may be inclined to normal relative to the longitudinal axis of the head shaft. Preferably, the bristles are inclined 10° to normal relative to the axis of rotation of the head shaft.

[0023] There is further described herein a driveable toothbrush attachment including: (a) a brush head including: (i) a head shaft having a cross-section which is polygonal in shape; and (ii) alternate rows of bristles and polishing tooth engaging elements located along the flat surfaces of the head shaft; and (b) an elongate housing adjacent the brush head including an elongate drive shaft adapted to operably engage the brush head, wherein the brush head undergoes rotational motion at a speed of between 60 and 240 rpm about an axis substantially co-axial with the drive shaft.

[0024] The present disclosure further provides a brush head for use with an electric toothbrush, said brush head having a head shaft configured to rotate about a longitudinal axis thereof, said brush head having a plurality of tooth engaging bristles composed of soft polymer material arranged in separate bristle tufts with each said bristle tuft having multiple bristles, the bristle tufts projecting outwardly from the head shaft and being provided in multiple rows spaced peripherally about said head shaft, each said row of bristle tufts extending along the head shaft with the bristle tufts in each said row being staggered in position along the head shaft relative to the bristle tufts in an adjacent said row of said bristle tufts. 8 2015207937 31 Μ 2015

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Possible and preferred features of the present invention will now be described with particular reference to the accompanying drawings. However, it is to be understood that the features illustrated in and described with reference to the drawings are not to be construed as limiting on the scope of the invention. In the drawings: [0026] Figure 1 a is a schematic side view of a toothbrush incorporating a driveable toothbrush attachment according to a first embodiment of the invention; [0027] Figure 1 b is an underneath view of a toothbrush having a different toothbrush attachment and a different location and configuration of control switches; [0028] Figure 2a is a perspective view of one embodiment of a brush head; [0029] Figure 2b is a side view of the brush head shown in Figure 2a; [0030] Figure 2c is a side view of part of a toothbrush with a guard; [0031] Figure 2d is a perspective view of the guard shown in Figure 2c; [0032] Figure 3a is a perspective view of a further embodiment of a brush head; [0033] Figure 3b is a side view of the brush head shown in Figure 3a; [0034] Figure 4a is a detailed view of yet another embodiment of a brush head; 2015207937 31 Μ 2015 9 [0035] Figure 4b is a detailed view of a still further embodiment of a brush head; [0036] Figure 4c is a detailed view of a still further embodiment of a brush head; [0037] Figure 4d is a detailed view of yet another possible embodiment of a brush head; [0038] Figure 5a is an end view of the embodiment of the brush head shown in Figure 4b; [0039] Figure 5b is an end view of the embodiment of the brush head shown in Figure 4b; [0040] Figure 5c is an end view of the embodiment of the brush head shown in Figure 4d; [0041] Figure 5d is an end view of a brush head with polishing heads located in apertures formed in the head shaft; [0042] Figure 6a is a perspective view of a portion of one possible embodiment of a head shaft; [0043] Figure 6b is a perspective view of a portion of a further possible embodiment of a head shaft; [0044] Figure 6c is a perspective view of a portion of a still further possible embodiment of a head shaft; 10 2015207937 31 Μ 2015 [0045] Figure 6d is a perspective view of a portion of yet another possible embodiment of a head shaft; [0046] Figure 7a is an end view of another embodiment of a head shaft; [0047] Figure 7b is a side view of the head shaft shown in Figure 7a; and

[0048] Figure 7c is a side view of a further embodiment of a head shaft. DETAILED DESCRIPTION

[0049] Referring to Figure 1a, there is shown an electric toothbrush (1) having a handle (10), a motor and gear housing (20) and an attachment (30) comprising an elongate drive shaft (31) and a brush head (40) which provides multiple tooth engaging elements (44). The brush head (40) may optionally include an end cap (not shown) to cover the brush head (40) when not in use.

[0050] At the base of the handle (10) are battery recharging terminals (11) adapted to sit in a recharging module as is well known in the art. The battery is a rechargeable nickel-cadmium battery capable of driving a small high speed electric motor (21) housed in the motoring gear housing portion (20). The motor is capable of rotating at about 6000 revolutions per minute (rpm). Accordingly, to adapt the motor (21) to use in a slow rotating brush head device according to the present invention, gear reduction is provided in the form of a small gear (22) operably engaged to a large gear (23), each gear (22, 23) of bevelled configuration to co-operate with each other. At the top of the housing (20) is a small bend (33) to enable the attachment (30) to extend at an angle relative to the longitudinal rotational axis of the motor (21) and its drive shaft (21 a). For this purpose, a universal joint (24) is provided between the gears (22, 23) and the drive shaft (31). The optimum angle is about 12°. 11 2015207937 31 Μ 2015 [0051] The handle (10) and motor and gear housing (20) are formed from a unitary piece by injection moulding. The handle includes a slight recess (12) to receive the palm of a user’s hand and a second control panel recess (25) at which is located a control panel including stop, forward and reverse buttons (27). The control buttons (27) are preferably enveloped in a flexible plastic film or cover (28) to waterproof the internal spaces of the housing (20) against ingress of water. The control panel recess (25) allows the user to use a thumb or a finger to operate the control buttons (27) and so to control the toothbrush (1).

[0052] The control buttons (27) in Figure 1a are shown arranged in a line in the longitudinal direction. However, in Figure 1 b the control buttons comprise a stop button (27a) for starting and stopping the motor, and a direction control button (27b) which can be rocked to left or right to switch the rotational direction between clockwise and counter clockwise. For brushing the teeth, the recommended direction is always away from the gums and towards the distal ends of the teeth. Therefore, for brushing the teeth of the upper jaw the rotational direction of the head (40) is such that the tooth engaging elements (44) are travelling downwardly when engaging the teeth. The direction control button (27b) may be rocked in that direction to cause the desired rotational direction of the head (40) as shown by arrows A, A' so that there is a mnemonic feature assisting the user. The opposite brushing directions are used for teeth of the lower jaw. Instead of rocking switch button (27b), two laterally adjacent individual rotation direction control switches can be used to provide the same mnemonics.

[0053] In a further possible modification (not shown in the drawings), the control buttons (27) may include a speed control switch means operative to selectively increase and decrease the rotational speed of the head (40). For example, a slower rotational speed, say about 100 rpm, may be preferable for a head having polishing elements (44), whereas for a head (40) having bristles as the elements (44) a faster speed, say 150-170 rpm, may be preferred. The different types of elements (44) are further described below. The speed control 2015207937 31 Μ 2015 12 switch may therefore have two positions corresponding to the two available speeds.

[0054] Alternatively, the switch may be a rocker switch having a stable control neutral position and two unstable speed change positions, e.g. on opposite sides of the central neutral position, with the switch being biased to return to the neutral position from both other positions. With this arrangement the user can move the switch to one side of its neutral position to increment the rotational speed and to the opposite side to decrement the speed. Releasing the switch will enable it to return to its neutral position to maintain the last operating speed. An electric speed controller can be responsive to this type of switch to control the output speed of the drive. This type of switch may be similar to switch (27b) in Figure 1b having left and right speed change positions on either side of the neutral speed maintain position.

[0055] The attachment (30) in Figure 1a is releasably engaged to the neck (26) of the housing by a snap-fit mechanism, such as deflectable tabs.

[0056] The drive shaft (31) is housed in a sheath (32) having an elongate conical shape which is widest at its base where it engages the housing neck (26) and tapers towards the brush head (40). To counteract vibration in the drive shaft (31), there may also be provided a counter-balance.

[0057] Although the brush head (40) is manufactured separately from the drive shaft (31) and sheath (32), these components are assembled in a non-reversible manner to reduce the potential for a choking hazard, particularly with regard to the brush head (40). The drive shaft (31) extends into the housing (20) and releasably engages the universal joint (24). At the brush head (40) end of the drive shaft (31), the brush head includes a head shaft (42) which directly connects to that end of the drive shaft (31). 13 2015207937 31 Μ 2015 [0058] In Figures 3a-3d, there is shown an embodiment or a brush head (40b) in which the head shaft (42b) is hexagonal in cross-section and the bristles (44b) radiate from the head shaft (42b). The bristles (44b) are arranged in six longitudinal rows corresponding to the six elongate faces of the head shaft (42b). It would of course be preferred that the bristles be arranged in individual spaced tufts along each face of the head shaft 42b. The head shaft (42b) has a bore (43) adapted to receive a corresponding protrusion from the drive shaft (31). As shown in Figure 2c, the embodiment includes a guard (45) pivotal about a pivot hinge (46). As shown in Figure 2d, the neck of the housing (32) includes a cleaning duct (27) to enable the brush head (40b) to be cleaned. The guard (45) covers a portion of the top of the brush head (40b) to improve the user’s comfort and prevent damage to soft buccal cavity tissue. Each of the ends of the rows of bristles (44c) may be tapered to present a smoother surface to the buccal cavity of the user. The head shaft (42b) can also be seen to taper at its respective ends to limit the discomfort caused by short bristles made relatively inflexible by their limited length.

[0059] Figures 3a and 3b show a brush head configuration (40e) in which the head shaft (42e) is hexagonal in cross-section. The bristles (44e) may be single elements about 1 mm in diameter represented in tufts of multiple bristles. Preferably, the bristles (44e) are single piece elongate elements made from a soft but resilient polymer such as may be obtained from DuPont, i.e. Tienex ® filaments. Preferably, in each case the filaments (44e) in length taper towards the opposed ends of the head shaft (42e) but the head shaft (42e) itself is a constant hexagonal cross-section throughout its length. As is shown in Figures 6a, 6b, the tufts of bristles (44e) extend radially from the axis of the shaft (42e) outwardly from each outer face of the hexagonal shape cross-section of the head shaft.

The tufts of bristles in each row are offset relative to the tufts of bristles in each adjacent row.

[0060] Turning to Figure 4b there is shown a head (40i) with a drive shaft (42i) of octagonal cross-section and bearing eight corresponding flat elongate surfaces 14 2015207937 31 Μ 2015 from which eight rows of filaments or bristles (44i) radiate arranged in tufts of multiple bristles (44i). As in Figures 3a, 3b, the tufts of bristles in one row are offset relative to the bristle tufts in an adjacent row, however, to facilitate a more thorough cleaning action, rows of tufts of bristles (44i) are inclined to the normal relative to the longitudinal axis of the head shaft (42i) so that opposed rows on either side of the brush head (40i) are inclined in one direction (in the drawing upwardly) by an angle of inclination of 10° (see rows 45a,b) and the alternately inclined opposed rows (46a, b) are slightly inclined in the other direction (in the drawing downwardly) at an angle of inclination of about 10° also. This variation in the inclination in the tufts of the bristles (44i) enhances the cleaning action of the brush head (40i). As is also shown in Figure 4b, the rows of tufts of bristles that are inclined may be interposed by rows of radially extending bristle tufts (46c, d, e), with a fourth row of such radially extending bristle tufts not seen in the drawing.

[0061] With reference to Figures 4a, 4c and 4d, in alternate arrangements every alternate row of bristles is substituted with a row of polishing elements (47a, c, d). These polishing elements (47a, c, d) are made from soft rubber or polymeric material in contrast to the nylon material of which the tufts of bristles are typically made. The rubber polishing elements (47a, c, d) are locatable in apertures in the faces of the head shaft (42j, k, m) but they include divergent elements (47c) as shown in Figure 4c presenting a “X” shaped outer face being the termination of four diverging arms extending from a cylindrical base. The “X” shaped head of the polishing elements (47c) facilitates the penetration of the edges of the polishing elements (47c) into crevices and gaps in the user’s teeth which would otherwise be inaccessible. In a slight variation, the polishing elements (47d) shown in Figure 4d are of a substantially constant “X” shaped cross-section and are locatable in key ways formed in rows of the head shaft (42j).

[0062] Referring to Figure 5a, the end view of a brush head (42e) also shown in Figure 3a is schematically represented. The tufts of bristles (44e) are shown to 15 2015207937 31 Μ 2015 be aligned in six straight rows but as shown in Figure 3a, the tufts of bristles in adjacent rows are offset relative to one another.

[0063] In Figure 5b, the embodiment also shown in Figure 4b is shown in end view to illustrate that the rows of tufts of bristles (44i) are aligned in straight rows. It will be appreciated that the rows may be spirally formed to provide another variation in the approach of the bristles as they rotate on the brush head (40i). However, the tufts of bristles in adjacent rows should be offset relative to one another.

[0064] Turning to Figure 5c, the polishing elements (47d) also shown in Figure 4d are shown to be beatable in V-shaped elongate recesses (48) located in between four equally spaced rows of bristles mounted on the head shaft (42j). The head shaft (42j) is of constant “X” shaped cross-section throughout its length.

[0065] Referring to Figure 5d, the polishing elements (47) may be simply beatable in the apertures formed in rows on a hexagonal cross-sectioned head shaft (42k).

[0066] In Figures 6a-6d, there are shown various key way configurations (49) for locating the polishing elements (47). In each case, the polishing elements (47) will include corresponding male or female portions to complement the key way shapes shown. The polishing elements (47) may be press fitted into the key ways (49) or may be slid from one end depending on the resilience of the respective materials and the type of engaging arrangement.

[0067] Figure 7a shows a cross-section of a hexagonal head shaft (42e) showing that the apertures for receiving the bristles and/or polishing elements may extend from the outer flat surface of each side of the head shaft (42e) through to a central bore (51). The central bore (51) may be used to co-operate with a complementary hexagonal shaped drive shaft (31 e) (See Figure 7c).

Figure 7b shows the head shaft (42e) in greater detail, including the apertures 16 2015207937 31 Μ 2015 (50) formed therein. As can be seen the apertures (50) in adjacent rows are offset relative to one another.

[0068] Figure 7c is a schematic drawing showing the apertures (50) formed in an octagonal shaped head shaft (42i) with an octagonal shaped central bore similar to that shown in Figure 4b. Of course, where the tufts of bristles (46a, b, c, d) are inclined, the aperture (50) will be correspondingly inclined to the normal. As can be seen, the apertures (50) in adjacent rows are offset relative to one another.

[0069] In another preferred arrangement, there is provided an automatic means for reversing the rotational direction of the brush head as the user changes the toothbrush from one side of the mouth to the other. The reverse direction means may include an inertia or gravitational toggle switch which either acts on reversible gears or on the motor to reverse its direction of rotation. Inertia and gravitational toggle switches are commercially available as modular units from electrical retailers, and the person skilled in the art will appreciate that small scale switches are preferable to ensure that the toothbrush unit remains lightweight and easy to manipulate.

[0070] The recommended direction for brushing of teeth is away from the gums and towards the distal or free ends of the teeth, and the present invention provides a rotary toothbrush having a reversible drive direction so that the user can switch the direction of rotation so that the recommended direction of brushing is being used when brushing the user’s teeth. However, it is inevitable that users will sometimes apply the rotating brushing head to teeth in a manner that the direction of rotation is opposite to the recommended direction. That is, the user will be brushing teeth in a direction away from the distal or free ends of the teeth and towards the gums. With known high speed oscillating electric toothbrushes or with previously proposed rotary toothbrushes (although no such rotary toothbrushes are known to have been successfully or widely produced and marketed), the speed of oscillation or rotation would be likely to give users 17 2015207937 31 Μ 2015 significant problems associated with abrading, irritating or pushing gums away from the teeth. For example, this can lead to microbial infections beneath the gums with consequent infection, inflammation, discomfort or distress caused by teeth and/or gum sensitivity in the exposed or disturbed areas. It has been surprisingly found, however, that using the very low rotational speeds taught by the present invention can eliminate or at least substantially remove the problems associated with brush movement direction against the gums in a direction away from the distal free ends of the teeth. The speed of rotation of the brushing head in the present invention is sufficiently low that the gums are not pushed back from the teeth in use.

[0071] Previously in this specification a preferred speed range of 60 to 240 rpm has been mentioned. It has been found that the optimal rotation speeds are less than 200 rpm. It has been found that higher speeds in the preferred range still have a tendency to dislodge and throw particles centrifugally away from the rotating brush head. A particularly preferred speed range is within the lowest third of the preferred speed range of 60 to 240 rpm, i.e. from 60 rpm up to about 150 rpm. A preferred optimal speed is about 100 rpm to minimise the centrifugal displacement and discharge of particulates while still achieving effective cleaning action and achieving the benefit of avoiding or minimising pushing of the gums back from the teeth if the rotating brush head is applied to teeth in the opposite direction to the recommended direction. Speeds towards the lower end of the preferred range of 60-240 rpm and even below the lower limit of that range can still effectively clean teeth but because the process is slower users may have a tendency to discontinue brushing before effective cleaning has occurred.

[0072] It has been found that there may be a significant psychological resistance or scepticism of users concerning the slow rotational speeds provided in the present invention. In fact, it is believed that there is a strong tendency of users seeing a tooth brushing head operating at a rotational speed of about 100 rpm to believe that speed will not be effective to clean teeth. It is surprising therefore and an unexpected result that a brush head rotational speed of in the 18 2015207937 31 Μ 2015 order of 100 rpm and preferably no more than about 150 rpm is optimal for effective cleaning while simultaneously avoiding or minimising any injurious action associated with pushing of gums back from the teeth if the rotating brush head is applied so that the rotation direction is opposite to the recommended direction of brushing away from the gums and towards the distal or free ends of the teeth.

[0073] In another aspect of the present invention, therefore, there is provided a method of cleaning a user’s teeth, the method comprising providing an electric toothbrush (1) having a handle (10) having a drive (21,22, 23) therein, switch means (27) for controlling the operation of the drive, and a driveable toothbrush attachment (30) extending outwardly and away from the handle in a longitudinal direction, the attachment including a brush head (40) having a plurality of tooth engaging elements (44). The brush head (40) is driven by the drive within the handle so as to rotate about an axis substantially corresponding to the longitudinal axis of the attachment.

[0074] The brush head (40) is applied to the user’s teeth and the user operates the switch means (27) to power the drive (21,22, 23) within the handle so that the drive rotates the brush head (40) at a rotational speed sufficiently low so as to avoid the teeth engaging elements (44) pushing the user’s gums backwardly from the teeth if the brush head is applied to the user’s teeth with the rotational direction being from the distal or free ends of the teeth and towards the gums, that rotational speed being in the range of 60 and 240 rpm. As mentioned above, the preferred rotational speed is in the range of 60 to about 150 rpm, and most preferably about 100 rpm.

[0075] The user operates the switch means to reverse the direction of rotation upon discontinuing brushing teeth at one side of the mouth and upon moving the toothbrush to apply the brush head to teeth of the same jaw at the other side of the mouth. The user also operates the switch means to reverse the direction of rotation upon discontinuing brushing teeth at one side of the mouth and moving the toothbrush to apply the brush head to teeth of the other jaw at the same side 2015207937 31 Μ 2015 19 of the mouth. These direction reversals keep the direction of brushing of the teeth engaging elements from the gums towards the distal or free ends of the teeth.

[0076] When used in this specification and claims, the terms “comprises” and “comprising” and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

[0077] While the present invention has been described in accordance with preferred compositions and embodiments, it is to be understood that certain substitutions and alterations may be made thereto without departing from the scope of the following claims.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. An electric toothbrush including: a drive arrangement including a grippable handle with a drive means mounted within the grippable handle, switch means for controlling operation of the drive means, and a drive shaft rotated about a drive axis by operation of the drive means; a housing releasably attachable to the drive arrangement, said housing having an elongated shape; an elongated driven shaft extending within the housing and operatively coupled to the drive shaft through a universal joint so that driven shaft extends at an acute angle to said drive shaft; and a brush head located at a distal end of the driven shaft and having a head shaft coupled to the driven shaft so as to be rotated thereby in use about a brush head rotation axis coincident with a rotation axis of said driven shaft, said brush head having a plurality of tooth engaging bristles composed of soft polymer material arranged in separate bristle tufts with each said bristle tuft having multiple bristles, the bristle tufts projecting outwardly from the head shaft and being provided in multiple rows spaced peripherally about said head shaft, each said row of bristle tufts extending along the head shaft with the bristle tufts in each said row being staggered in position along the head shaft relative to the bristle tufts in an adjacent said row of said bristle tufts, wherein the drive arrangement includes a button or switch for switching the rotational direction of the brush head.
2. An electric toothbrush according to claim 1, further including a guard for said brush head mounted to or forming part of said housing, located around part of one side of the brush head and along a full length of the brush head so as to shield soft tissues of a user’s mouth except from the bristles exposed on the brush head at an opposite side to said guard.
3. An electric toothbrush according to claim 1 or claim 2, wherein, in use, the brush head is rotated at a speed between 60 and 240 rpm, preferably between 60 and 150 rpm, and more preferably about 100 rpm.
4. An electric toothbrush according to any one of claims 1 to 3 wherein said brush head includes releasable attachment means to enable releasable attachment to said driven shaft.
5. An electric toothbrush according to any one of claims 1 to 4, wherein the button or switch for switching the rotational direction of the brush head is user actuated.
6. A replaceable toothbrush attachment to the electric toothbrush of any one of claims 1 to 5, said toothbrush attachment including: the housing releasably attachable to the electric toothbrush drive arrangement, the housing having an elongated shape extending in a direction at an acute angle to the drive axis of the drive shaft; the elongated driven shaft extending along and within the housing and, in use, operatively coupled to the drive shaft of the electric toothbrush drive arrangement through a universal joint so that the rotation of the drive shaft is transmitted to the driven shaft extending at the acute angle thereto; and the brush head located at a distal end of the driven shaft and having a head shaft drivingly coupled to the driven shaft so as to be rotated thereby in use about a brush head rotation axis coincident with said driven shaft, the brush head having a plurality of tooth engaging bristles composed of soft polymer material arranged in separate bristle tufts with each said bristle tuft having multiple bristles, the bristle tufts projecting outwardly from the head shaft and being provided in multiple rows spaced peripherally about said head shaft, each said row of bristle tufts extending along the head shaft with the bristle tufts in each said row being staggered in position along the head shaft relative to the said bristle tufts in an adjacent said row of bristle tufts, wherein the brush head is configured so that its rotational direction can be switched by the button or switch of the drive arrangement.
7. An electric toothbrush according to any one of claims 1 to 5 or a replaceable toothbrush attachment according to claim 6, further including a guard for said brush head mounted to or forming part of said housing, located around part of one side of the brush head and along a full length of the brush head so as to shield soft tissues of a user's mouth except from the bristles exposed on the brush head at an opposite side to the guard.
8. An electric toothbrush or a replaceable toothbrush attachment according to claim 7, wherein the guard is pivotally mounted to said housing whereby in a first operative position said guard extends fully along said brush head and in a second inoperative position said guard is pivoted away from said brush head.
9. An electric toothbrush of any one of claims 1 to 5, 7 or 8 or a replaceable toothbrush attachment according to any one of claims 6 to 8, wherein the acute angle is about 12 degrees.
10. An electric toothbrush of any one of claims 1 to 5 or 7 to 9 or a replaceable toothbrush attachment according to any one of claims 6 to 9, wherein said housing has releasable attachment means located at one end enabling attachment to the grippable handle of said electric toothbrush drive arrangement at said acute angle.
11. An electric toothbrush of any one of claims 1 to 5 or 7 to 10 or a replaceable toothbrush attachment of any one of claims 6 to 10, wherein the bristles in each said bristle tuft extend radially from said head shaft.
12. An electric toothbrush of any one of claims 1 to 5 or 7 to 10 or a replaceable toothbrush attachment of any one of claims 6 to 10, wherein the bristles in each said bristle tuft in at least some of said rows of said bristle tufts extend at an inclined angle to said head shaft.
13. An electric toothbrush or a replaceable toothbrush attachment as claimed in claim 12, wherein the bristle tufts in a row of inclined said bristle tufts are configured at the same inclined angle, preferably the inclined angle is about 10° to a radial direction.
14. An electric toothbrush or a replaceable toothbrush attachment as claimed in claim 13, wherein there is provided at least two rows of inclined said bristle tufts where the inclined angle is in opposite directions in said two rows.
15. An electric toothbrush of any one of claims 1 to 5 or 7 to 14 or a replaceable toothbrush attachment of any one of claims 6 to 14, further including at least one row of separately spaced polishing elements positioned along the brush head, each said polishing element projecting outwardly with an outer distal end, preferably wherein the outer distal end of each said polishing element has an "X" configuration.
16. An electric toothbrush or a replaceable toothbrush attachment according to claim 15, wherein a free length of said polishing elements at opposed ends of the brush head are reduced relative to said polishing elements in an intermediate zone between said opposed ends.
17. An electric toothbrush of any one of claims 1 to 5 or 7 to 16 or a replaceable toothbrush attachment according to any one of claims 6 to 16, wherein a free length of said bristle tufts at opposed ends of the brush head are reduced relative to bristle tufts in an intermediate zone between said opposed ends.
18. An electric toothbrush of any one of claims 1 to 5 or 7 to 17 or a replaceable toothbrush attachment according to any one of claims 6 to 17, wherein said head shaft has a uniform polygonal shape ora cross shape along its length providing flat longitudinal surfaces for mounting said bristle tufts from.
19. An electric toothbrush or a replaceable toothbrush attachment according to claim 18, wherein the polygonal shape is a hexagon or an octagon.