AU2005222538A1 - Electric toothbrush - Google Patents

Description

13/10/2005 13:55 61-3-98901337 PATENT ATTOIRNEY SERV PAGE

AUSTRALIA

Patents Act 1990 COMPLETE

SPECIFICATION

FOR A STANDARD

PATENT

ORIGINAL

Applicant(s): CRAIG HILLS Actual Inventor(s): CRAIG HILLS Address for Service: PATENT ATTORNEY

SERVICES

26 Ellingworth Parade Box Hill Victoria 3128 Australia Title: ELECTRIC

TOOTHBRUSH

Associated Provisional Applications: No(s).: The following statement is a full description of this invention, including the best method of perfonrming it known to le/usb:- 1 COMS ID No: SBMI-01731920 Received by IP Australia: Time 14:02 Date 2005-10-13 13/10/2005 13:55 61-3-98901337 PATENT ATTORNEY SERV PAGE 06 SELECTRIC TOOTHBRUSH C1 PRIOR APPLICATIONS O This is a divisional application of PCT/AU2004/000320, filed 17 March 2004 en that claims priority from Australian patent application nos. 2003901241, 2003901242, 2003901243, 2003901244 all filed on 17 March 2003.

00 C- FIELD OF INVENTION This invention relates to electric toothbrushes. More particularly, this invention Srelates to electric toothbrushes with rotatable toothbrush heads and methods of brushing teeth using the same.

BACKGROUND OF THE T NuTTON 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.

It is an object of the present invention to provide a rotating electric toothbrush which can be effective to brush and clean a user's teeth.

It is a further object of the present invention to provide a rotating electric toothbrush which can be capable of use with minimal or no or reduced damage or irritation to gums.

It is a further object of the present invention to provide a method of effectively using a rotating electric toothbrush to brush and clean a user's teeth.

2 COMS ID No: SBMI-01731920 Received by IP Australia: Time 14:02 Date 2005-10-13 13/10/2005 13:55 61-3-98901337 PATENT ATTORNEY SERV PAGE 07 o SUMMARY OF THE INVENTION According to one aspect of the invention, there is provided an electric toothbrush O having a handle with a drive therein and switch means for controlling operation of the drive, and a driveable toothbrush attachment which include a brush head having a plurality of tooth engaging elements, the brush head operably engaging an elongate drive 0 shaft which is operably associated with the drive so as to be drivingly rotated thereby, wherein the drive operates to rotate the brush head at a rotational speed of between t and 240 revolutions per minute (rpm.) about an axis substantially corresponding to the 0 longitudinal axis of the drive shaft.

In one preferred aspect there is provided 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 s1 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 and 240 rpm), about an axis substantially corresponding to the longitudinal axis of the drive shaft.

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 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.

3 COMS ID No: SBMI-01731920 Received by IP Australia: Time 14:02 Date 2005-10-13 13/10/2005 13:55 61-3-98901337 PATENT ATTORNEY SERV PAGE 08 S The drive shaft may be flexible and may comprise a flexible metal wire or C polymer rod. The drive shaft may comprise a metal or polymeric cable, optionally O comprising a plurality of strands for increased strength and flexibility. Alternatively, the _3 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 0 may be made from any material found to be suitable in the corresponding component of C driven toothbrushes of the prior art t The driveable toothbrush attachment may include guard means to protect the soft S 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. The guard means may be completely removable for applications where it is considered unnecessary. 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.

The speed of the rotational motion of the brush head is between 30 and 600 revolutions per minute (rpm), 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 tooth brushing devices. Also these slow speeds minimise or 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 4 COMS ID No: SBMI-01731920 Received by IP Australia: Time 14:02 Date 2005-10-13 13/10/2005 13:55 61-3-98901337 PATENT ATTORNEY SERV PAGE 09 Scentrifugal discharge of particulates. The tooth engaging elements may include a variety of different types of elements. Preferably, the tooth engaging elements comprise a O 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 00 M aligned along the length of the brush head. Preferably, the alternating rows are arranged C parallel to the longitudinal axis of the brush head.

m Preferably, the brush head includes a head shaft on which the tooth engaging o 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-sectioi 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.

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 drive shaft and sheath to the existing COMS ID No: SBMI-01731920 Received by IP Australia: Time 14:02 Date 2005-10-13 13/10/2005 13:55 61-3-98901337 PATENT ATTORNEY SERV PAGE g unit. As the typical toothbrush electric motor available in the marketplace prior to this c invention was a small high speed motor capable of running at speeds of 6000 rpm, the O rotational speed must be modified by a gearing system to translate the high speed rotation Cn of the electric motor to low speed rotation of the brush head. Alternatively, a slow speed electric motor may be employed.

00 M One or more types of the tooth engaging elements may be inclined to normal C^ relative to the longitudinal axis of the head shaft. Preferably, the bristles are inclined tt to normal relative to the axis of rotation of the head shaft.

O In another aspect there is provided a driveable toothbrush attachment including: a brush head including: 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 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.

According to a further aspect of the invention there is provided a method of cleaning a user's teeth, the method including: providing an electric toothbrush with a handle having a drive therein, switch means for controlling the operation of the drive, and a driveable toothbrush attachment extending outwardly and away from the handle in a longitudinal direction, the attachment including a brush head having a plurality of tooth engaging elements, the brush head being driven by the drive within the handle so as to rotate about an axis substantially corresponding to the longitudinal axis of the attachment, 6 COMS ID No: SBMI-01731920 Received by IP Australia: Time 14:02 Date 2005-10-13 I^ I 13/10/2005 13:55 61-3-98901337 PATENT ATTORNEY SERV PAE 11 /IU/ 2Ub S:b b3 bl-J-auaB1337 PATENT ATTORNEY SERV PAGE 11 applying the brush head to the user's teeth, and operating the switch means to power the CA drive within the handle so that the drive rotates the brush head at a rotational speed 0 sufficiently low so as to avoid the teeth engaging elements pushing the user's gums Sbackwardly from the teeth if the brush head is applied to the user's teeth with the 0 5 rotational direction being from the distal or free ends of the teeth and towards the gums, 00 m€ that rotational speed being in the range 60 and 240 rpm.

t BRIEF DESCRIPTION OF THE DRAWINGS 0 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: Figure la is a schematic side view of a toothbrush incorporating a driveable toothbrush attachment according to a first embodiment of the invention; 1$ Figure lb is an underneath view of a toothbrush having a different toothbrush attachment and a different location and configuration of control switches; Figure 2 a is a perspective view of a second embodiment of a brush head; Figure 2b is a side view of the brush head shown in Figure 2a; Figure 2c is a side view of the toothbrush with a guard; Figure 2d is a detailed view of the toothbrush that has a hood; Figure 3a is a perspective view of a third embodiment of a brush head; Figure 3b is a side view of the brush head shown in Figure 3a; Figure 3c is a side view of the toothbrush with a guard; Figure 3d is a detailed view of the toothbrush that has a hood; Figure 4a is a perspective view of a fourth embodiment of a brush head; 7 COMS ID No: SBMI-01731920 Received by IP Australia: Time 14:02 Date 2005-10-13 13/10/2005 13:55 61-3-98901337 PATENT ATTORN'EY SERV PAGE 12 Figure 3b, is a side view of the brush head shown in Figure 3a; CA Figure 3c is a side view of the toothbrush with a guard; o Figure 3d is a. detailed view of the tootlibrush that has a hood; Figure 4a. is a perspective view of a fourth embodiment of a brush head; s Figure 4b is a side view of a head shaft component;, 00 Figure 4c is a side view of the brush bead shown, in Figure 4a; Mi Figure 4d is a side view of the toothbrush with a guard; Figure 4e is a detailed view of the toothbrush that has a hood; 0 Figure 5a is a perspective view of a fifth embodiment of a brush head; Figure 5b is a side view of a bead shaft com-ponent; Figure 5e is a side view of the brush head shown in Figure Figure Sd is a side view of the toothbrush with a guard; Figure 5e is a detailed view of the toothbrush that has a hood; Figure 6a is a perspective view of a sixth embodiment of a brush head;, Figure 6b is side view of the brush head shown in Figure 6a; Figure 6c is a detailed view of the brush head shown in~ Figure 6a; Figure 6d is a detailed view of tbe brush head shown in Figure 6a; Figure 7a. is a detailed view of a seventh embodiment of a brush head, Figure 7b is a detailed view of an eight emabodiment of a brush head; Figure 7c is a detailed view of a ninth embodiment of a brush bead; Figure 7d is a detailed view of a tenth embodiment of a brush head; Figure 8a is a cross-sectional view of the sixth embodiment of the brush head shown in Figure Oa; Figure 8b is a cross-sectional view of the sixth embodiment of the brush head shown in Figure 7b; COMS ID No: SBMI-01731920 Received by IP Australia: Time 14:02 Date 2005-10-13 13/10/2005 13:55 61-3-98901337 PATENT ATTORNEY SERV PAGE 13 Figure 8c is a cross-sectional view of the sixth embodiment of the brush head shown in Figure 7d; O Figure 8d is a cross-sectional view of a brush head with polishing heads located in apertures formed in the head shaft; S Figure 9 is a cross-sectional side view of an eleventh embodiment of a brush 00 M head; Figure 10a is a perspective view of a portion of a second embodiment of a head n shaft; 0 Figure lOb is a perspective view of a portion of a third embodiment of a head shaft; Figure 10c is a perspective view of a portion of a fourth embodiment of a head shaft; Figure 10d is a perspective view of a portion of a fifth embodiment of a head shaft; Figure 1 la is an end view of a sixth embodiment of a head shaft; Figure 1 lb is a side view of the head shaft shown in Figure 1 la; and Figure 1 lc is a side view of a seventh embodiment of a head shaft.

DETAILED DESCRIPTION Referring to Figure la, there is shown an electric toothbrush having a handle 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.

9 COMS ID No: SBMI-01731920 Received by IP Australia: Time 14:02 Date 2005-10-13 13/10/2005 13:55 61-3-98901337 PATENT ATTORNEY SERV PAGE 14 o At the base of the handle (10) are battery recharging terminals (1 1) adapted to sit in a recharging module as is well known in the art The battery is a rechargeable nickel- 0 cadmium battery capable of driving a small high speed electric motor (21) housed in the -motoring gear housing portion The motor is capable of rotating at about 6000 S 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 each gear (22, 23) Sof bevelled configuration to co-operate with each other. At the top of the housing (20) is O a small bend whereby to extend the attachnent (30) at an angle relative to the T0 longitudinal rotational axis of the motor For this purpose, a universal joint (24) is provided between the gears (23, 22) and the drive shaft The optimum angle is about 12°.

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 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 contro panel recess (25) allows the user to use a thumb to operate the control buttons (27) and so to control the toothbrush The control buttons (27) in Figure la are shown arranged in a line in the longitudinal direction. However, in Figure I 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 clockvise. For brushing the teeth, the recommended direction is always away from the gums and towards the distal ends of the teet.. Therefore, for brushing the teeth of the COMS ID No: SBMI-01731920 Received by IP Australia: Time 14:02 Date 2005-10-13 13/10/2005 13:55 61-3-98901337 PATENT ATTORNEY SERV PAGE be rocked to left or right to switch the rotational direction between clockwise and counter C clockwise. For brushing the teeth, the recommended direction is always away from the O 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 00 n button (27b) may be rocked in that direction to cause the desired rotational direction of C^ 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 0 rocking switch button 27b, two laterally adjacent individual rotation direction control switches can be used to provide the same mnemonics.

In a further possible modification (not shown in the drawings), the control buttons (27) may include speed control switch means operative to selectively increase and decrease the rotational speed of the head For example, a slower rotational speed, say about 100 rpm, may be preferable for a head having polishing elements 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 switch may therefore have two positions corresponding to the two available speeds.

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 po.ition to maintain the last operating speed. An electric speed controller can be responsive to this type of 11 COMS ID No: SBMI-01731920 Received by IP Australia: Time 14:02 Date 2005-10-13 13/10/2005 13:55 61-3-98901337 PATENT ATTORNEY SERV PAGE 16 Ft The attachment (30) in Figure la is releasably engaged to the neck (26) of the c housing by a snap-fit mechanism, such as deflectable tabs.

0 O The drive shaft (31) is housed in a sheath (32) having an elongate conical shape e which is widest at its base (32) where it engages the housing neck (26) and tapers towards the brush head To counteract vibration in the drive shaft there is 00 C provided a counter-balance (33).

Although the brush head (40) is manufactured separately from the drive shaft (31) in and sheath these components are assembled in a non-reversible manner to reduce o the potential for a choking hazard, particularly with regard to the brush head The drive shaft (31) extends into the housing (20) and releasably engages the universal joint At the brush head (40) end of the drive shaft the brush head includes a head shaft (42) which directly connects to that end of the drive shaft (31).

Turning to Figures 2a-2d, there is shown a brush head (40a) comprised of a cylinder formed from a high density of bristles (44) radiating from a head shaft (42a). In particular, Figure 2a shows the head shaft (42a) as including an aperture (43) adapted to receive a corresponding protrusion from a drive shaft (31 a).

As shown in Figure 2c, this embodiment includes a tiltable and removable guard hinged to the housing neck (26) by standard means of a protrusion and aperture combination As shown in Figure 2d, the housing neck (26) includes a water cleaning duct (27) to enable the brush head (40a) to be cleaned. The guard (45) includes a hood (46) to cover a portion of the top of the brush head (40a) to improve the user's comfort and prevent damage to soft buccal cavity tissue.

In Figures 3a-3d, there is shown another embodiment 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 12 COMS ID No: SBMI-01731920 Received by IP Australia: Time 14:02 Date 2005-10-13 13/10/2005 13:55 61-3-98901337 PATENT ATTORNEY SERV PAGE 17 0 elongate faces of the head shaft (42b). Otherwise, the operation of the embodiment shown in Figures 3a-3d is substantially the same as that of the embodiment shown in O Figures 2a-2d.

In Figures 4a-4e there is shown a brush head (40c) having six radiating rows of bristles (44c) in the same manner as those shown in Figures 3a-3c. However, to increase 00 user comfort, the ends of each row of bristles (44c) is tapered to present a smoother C surface to the buccal cavity of the user. The head shaft (42c) can also be seen to taper at t its respective ends to limit the discomfort caused by short bristles made relatively o inflexible by their limited length.

Figures 5a-5c show a brush head (40d) in which the rows of bristles are more numerous than those shown in Figure 4a and are more densely packed whereby to provide a cylindrical brush head similar to that of Figure 2a, except that the respective ends of the brush head and corresponding head shaft (42d) are tapered.

Figures 6a-6d show various brush head configurations (40e-40b.) in which the head shaft (42e-42h) is hexagonal in cross-section in each case. The bristles (44e-44h) may be single elements about Imm in diameter or may represent tufts of bristles as is standard in the art. Preferably, the bristles (44e-44h) 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-44h) taper towards the ends of the head shaft (42e-42h) but the head shaft (42e-42h) comprises a constant hexagonal cross-section throughout its length.

Turning to Figure 7b there is shown a drive shaft (42i) of octagonal cross-section and bearing eight corresponding flat elongate surfaces from which eight rows of filaments or bristles (44i) radiate. To facilitate a more thorough cleaning action, every alternate row of bristles (44i) is inclined to the normal relative to the longitudinal axis of 13 COMS ID No: SBMI-01731920 Received by IP Australia: Time 14:02 Date 2005-10-13 13/10/2005 13:55 61-3-98901337 PATENT ATTORNEY SERV PAGE 18 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) to an angle of inclination of 10 (see 0 rows 45a-b) and the alternately inclined opposed rows (46a, b) are slightly inclined in Sthe other direction (in the drawing downwardly) at an angle of inclination of about 100 Salso. This variation in the inclination of the bristles (44i) enhances the cleaning action of 0 0 the brush head With reference to Figures 7 a, 7c and 7d, in alternate arrangements every alternate c row of bristles is substituted with a row of polishing elements (47a, c, These S polishing elements 47a, d are made from soft rubber or polymeric material in contrast to the nylon material of which t.e bristles are typically comprised. The rubber polishing elements 4 7a c, d) are universally locatable in the Imm apertures but they include divergent elements 4 7c) as shown in Figures 7c presenting a shaped top 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 7d are of substantially constant "X shaped cross-section and are locatable in key ways formed in rows of the head shaft (42j).

Referring to Figure 8a, the end view of a brush head 42 e) also shown in Figures 6a is schematically represented. The bristles (44e) are shown to be aligned in six straight rows. In an. alternate embodiment, the rows of apertures on the head shaft may be formed in a spiral pattern whereby to provide greater variation in the approach of the bristles to the user's teeth to facilitate an improved clean and/or polishing performance.

In Figure 8b, the embodinent also shown in Figure 7b is shown in end view to illustrate that the rows of bristles (44i) are aligned in straight rows. It will be appreciated 14 COMS ID No: SBMI-01731920 Received by IP Australia: Time 14:02 Date 2005-10-13 13/10/2005 13:55 61-3-98901337 PATENT ATTORNEY SERV PAGE 19 S that the rows may be spirally formed to provide another variation in the approach of the cl bristles as they rotate on the brush head O Turning to Figure 8c, the polishing elements (47d) also shown in Figure 7d are shown to be locatable in V-shaped elongate recesses (48) located in between four equally 0 5 spaced rows of bristles mounted on the head shaft (42j). The head shaft (42j) is of M: constant shaped cross-section throughout its length.

C Referring to Figure 8d, the polishing elements (47) may be simply locatable in the I mm apertures formed in rows on a hexagonal cross-sectioned head shaft (42k).

0 In Figures 10a. 0d, there are shown various key way configurations for locating the polishing elements In each case, the polishing elements (47) will include corresponding male or female portions to complement the key way shapes shown. The polishing elements may be press fit into the key ways (49) or may be slid from one end in depending o the resilience of the respective materials and the type of engaging arrangement Figure l a shows a cross-section of a hexagonal head shaft 4 2 e) 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 The central bore (51) may be used to co-operate with a complementary hexagonal shaped drive shaft (31e). Figure I lb shows the head shaft (42e) in greater detail, including the apertures (50) formed therein.

Figure I e is a schematic drawing showing the apertures (50) formed in an octagonal shaped head shaft (42i) similar to that shown in Figure 7b. Of course, where the bristles (44i) are inclined, the aperture (50) will correspondingly be inclined to the normal.

I1 COMS ID No: SBMI-01731920 Received by IP Australia: Time 14:02 Date 2005-10-13 13/10/2005 13:55 61-3-98901337 PATENT ATTORNEY SERV PAGE In another preferred arrangement, there is provided an automatic means for reversing the rotational direction of the brush bead as the user changes the toothbrush t from one side of the mouth to the other. The reverse direction means may include an Sinertia 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 0n commercially available as niodujar 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.

The recommended direction for brushing of teeth is away from the gums and 0to 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 rotatin so that the recommended direction of brushing is being used when brushing the ser'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 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 as ee surprising found, however, that sensitivity i the exposed or d rbed areas. t has been surprising found, however, at using thevery low rotatio speeds taught by the present invention can eliminate or at least substantially remove the problems associated with brush movement direction 16 COMS ID No: SBMI-01731920 Received by IP Australia: Time 14:02 Date 2005-10-13 13/10/2005 13:55 61-3-98901337 PATENT ATTORNEY SERV PAGE 21 0 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 ow that the g s are O not pushed back from the teeth in use.

SPreviously 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 00 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 Ct preferred speed range is within the lowest third of the preferred speed range of 60 to 240 p preferred ospeed is about 100 rpm rpm, i.e. from 60 rprn 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 linit 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.

It has been found that there may be a significant psychological resistance or scepticism of users conceming 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 order of 100 rpm and preferably .no more than about 150 rpm is optimal for effective cleaning while simultaneously avoiding or minimising any injurio action associated with pushing of gums back from the teeth if the rotating 17 COMS ID No: SBMI-01731920 Received by IP Australia: Time 14:02 Date 2005-10-13 13/10/2005 13:55 61-3-98901337 PATENT ATTORNEY SERV PAGE 22 brush head is applied so that the rotation direction is opposite to the recommended Sdirection of brushing away from the gums and towards the distal or free ends of the teeth.

O In another aspect of the present invention, therefore, there is provided a method of C 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 OO controlling the operation of the drive, and a driveable toothbrush attachment extending outwardly and away from the handle in a longitudinal direction, the attachment I including a brush head (40) having a plurality of tooth engaging elements 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.

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 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.

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 of the mouth. These direction reversals 18 COMS ID No: SBMI-01731920 Received by IP Australia: Time 14:02 Date 2005-10-13 13/10/2005 13:55 61-3-98901337 PATENT ATTORNEY SERV PAGE 23 o keep the direction of brushing of the teeth engaging elements from the gums towards the C1 distal or free ends of the teeth.

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

00 en 19 ,l ,l 19 COMS ID No: SBMI-01731920 Received by IP Australia: Time 14:02 Date 2005-10-13

Claims (16)

1. An electric toothbrush having a handle with a drive therein, switch means for 0 controlling operation of the drive, and a driveable toothbrush attachment, the toothbrush C including: a brush head having a plurality of tooth engaging elements, the brush head being 00 0O located and coupled to an elongate drive shaft which is operably associated with the drive N so as to be drivingly rotated thereby, wherein the drive operates to rotate the brush head at a rotational speed of between 60 and 240 revolutions per minute (rpm) about an axis O substantially corresponding to the longitudinal axis of the drive shaft.

2. The toothbrush of claim I wherein the rotational speed of the brush head is between 60 and about 150 rpm.

3. The toothbrush of claim 2 wherein the rotational speed of the brush head is about 100 rpm.

4. The toothbrush of any preceding claim, wherein the tooth engaging elements include a combination of polishers as well as bristles. The toothbrush of claim 4, wherein the bristles and polishers are located in alternating rows aligned parallel to the longitudinal axis of the brush head.

6. The toothbrush of claim 4 or 5, wherein the brush head includes a central head shaft and the bristles and polishers extend outwardly from the head shaft.

7. The toothbrush of any one of claims 4 to 6, wherein the polishers include edges which facilitate the penetration of the polishers into crevices or gaps in the user's teeth.

8. The toothbrush of any one of claims 4 to 7, wherein the polishers are made from soft rubber or polymeric material.

9. The toothbrush of claim 7, wherein at least one of the polishers is X-shaped in cross-section. COMS ID No: SBMI-01731920 Received by IP Australia: Time 14:02 Date 2005-10-13 13/10/2005 13:55 61-3-98901337 PATENT ATTORNEY SERV PAGE The toothbrush of any one of the preceding claims, wherein the brush head includes a central head shaft which is tapered at one or both ends to permit corresponding 0 0 tapering by the tooth engaging elements at the or each tapered end. Cn

11. The toothbrush of any one of the preceding claims, wherein the attachment is adapted for connection to toothbrush drive means having a gravitational toggle switch 00 C which effectively reverses the direction of rotation of the head shaft depending on the left-handed or right-handed orientation of the toothbrush. I) 12. The toothbrush of claim 1 or 2 wherein the drive is selectively operable to rotate 0 o the brush head at any one of a plurality of rotational speeds, the switch means being selectively operable by the user to selectively change the rotational speed.

13. The toothbrush of claim 12 wherein the switch is selectively movable between different positions in one of which the speed is incremented, and in another of which the speed is decremented.

14. A method for making a driveable toothbrush attachment, comprising: a) inserting a plurality of tooth engaging elements in recesses formed therefor in a head shaft to form a brush head; and b) operably engaging the head shaft to an elongate drive shaft, wherein the brush head is operable to rotate at a speed of between 60 and 240 revolutions per minute (rpm) about an axis substantially corresponding to the longitudinal axis of the drive shaft.

15. The method of claim 14, wherein step a) further comprises the step of: i) moulding the head shaft polygonal in cross-section whereby to present a plurality of rows of recesses along each face of the polygon.

16. The method of claim 15, wherein step a) further comprises the steps of: 21 COMS ID No: SBMI-01731920 Received by IP Australia: Time 14:02 Date 2005-10-13 13/10/2005 13:55 61-3-98901337 PATENT ATTORNEV SERV PAGE 26 0 ii) forming recesses in the form of rows of cylindrical bores in the external Ssurface of the head shaft, the bores generally radiating from the longitudinal axis thereof; O and iii) inserting rows of bristles alternating with rows of polishers in the bores.

17. The method of claim 16, wherein the recesses formed in step ii) are set at an 00 M oblique angle relative to the longitudinal axis of the head drive whereby the tooth engaging elements are inclined to the normal relative to the surface of the head shaft.

38. A method of cleaning a user's teeth, the method including: Sproviding an electric toothbrush with a handle having a drive therein, switch means for controlling the operation of the drive, and a driveable toothbrush attachment extending outwardly and away from the handle in a longitudinal direction, the attachment including a brush head having a plurality of tooth engaging elements, the brush head being driven by the drive within the handle so as to rotate about an axis substantially corresponding to the longitudinal axis of the attachment, applying the brush head to the user's teeth, and operating the switch means to power the drive within the handle so that the drive rotates the brush head at a rotational speed sufficiently low so as to avoid the teeth engaging elements 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 60 and 240 rpm. 19. The method of claim 16 wherein the rotational speed of the brush head is between and about 150 rpm. The method of claim 19 wherein, the rotational speed of the brush head is about 100 rpm. 22 COMS ID No: SBMI-01731920 Received by IP Australia: Time 14:02 Date 2005-10-13 13/10/2005 13:55

61-3-98901337 PATENT ATTORNEY SERV PAGE 27 6 21. The method of claim 18, 19 or 20, further including the step of operating the C switch means to reverse the direction of rotation upon discontinuing bushing teeh at one O side of the mouth and moving the toothbrush to apply the brush bead to teeth of the same n jaw at the other side of the mouth. 22. The method of claim 18, 19 or 20 further including the step of operating the 00 switch means to reverse the direction of rotation upon discontinuing brushing teeth at one l side of the mouth and moving the toothbrush to apply the brush head to teeth of the other C jaw at the same side of the mouth. 0 0 Dated this 12 th day of October 2005 PATENT ATTORNEY SERVICES Attorneys for CRAIG HILLS 23 COMS ID No: SBMI-01731920 Received by IP Australia: Time 14:02 Date 2005-10-13