CN111818874B

CN111818874B - Electric tooth brush

Info

Publication number: CN111818874B
Application number: CN201980017757.2A
Authority: CN
Inventors: 林丽容
Original assignee: Life Works Products Ltd
Current assignee: Life Works Products Ltd
Priority date: 2018-01-09
Filing date: 2019-01-09
Publication date: 2022-04-08
Anticipated expiration: 2039-01-09
Also published as: WO2019138330A1; CN111818874A

Abstract

A toothbrush accessory (100) for detachable attachment to a motor drive unit of an electric toothbrush, wherein the toothbrush accessory (100) comprises: a main housing (110) comprising a tubular neck portion (213) having a longitudinal axis (X-X') and a head portion (215) defining a toothbrush receptacle (216); a toothbrush head (200) rotatably mounted on a toothbrush receiving portion (216) of the head portion (215) and a rotatable brush axis (Z-Z'); and a drive coupling mechanism (280) mounted within the neck portion (213) and having an axis of rotation (Y-Y'); the drive coupling mechanism (280) comprises a crankshaft (230), a bushing arrangement (240) and a coupling shaft portion; the coupling shaft portion includes engagement means at an axially free end portion, the crank shaft (230) drives the toothbrush head (200) to rotate reciprocally about a brush axis (Z-Z'), and the coupling shaft portion and the crank shaft (230) are integrally formed as a unitary member and the crank shaft (230) is rotatably mounted on bushing means (240).

Description

Electric tooth brush

Technical Field

The present disclosure relates to the field of oral care devices, and in particular to electric toothbrushes. More particularly, the present disclosure relates to a brush head for a power toothbrush.

Background

Electric toothbrushes provide a convenient, useful and effective alternative to manual toothbrushes. A typical modern electric toothbrush includes a motor-driven base unit and a toothbrush attachment removably attached to the base unit. Toothbrush attachments typically include a head having a forward facing surface that will engage the teeth of the user and rotate or vibrate over the teeth to aid in tooth cleaning. A removable toothbrush attachment is advantageous and facilitates periodic replacement of the brush head at regular intervals at a reasonably low cost. A motor drive unit, commonly referred to as a drive unit or handpiece (handdie), typically includes a motor and a motor-driven drive shaft that drives the brushhead in a cleaning rotation. The cleaning rotation is typically a reciprocating rotation about the rotation axis between a first rotation angle and a second rotation angle.

Disclosure of Invention

A toothbrush accessory for removable attachment to a motor drive unit of an electric toothbrush is disclosed. The motor drive unit comprises a motor and a motor-driven drive shaft, which will rotate reciprocatingly around the axis of rotation of the drive shaft. The toothbrush attachment comprises: a main housing including a tubular neck portion having a longitudinal axis and a head portion defining a toothbrush receiving portion; a toothbrush head rotatably mounted on the toothbrush receiving portion of the head portion and a rotatable brush axis; and a drive coupling mechanism mounted inside the neck portion and having an axis of rotation. The drive coupling mechanism includes a crankshaft, a bushing arrangement, and a coupling shaft portion. The coupling shaft portion comprises at an axial free end portion an engagement means adapted for detachably coupled driving engagement with a drive shaft of the motor drive unit for receiving rotational drive power from the drive shaft and for transmitting the received rotational drive power to the crankshaft. The crank shaft is for driving the brush head to reciprocally rotate about the brush axis, and wherein the coupling shaft portion and the crank shaft are integrally formed as a unitary member and the crank shaft is rotatably mounted on the bushing arrangement.

Drawings

The disclosure of the invention will be described, by way of example, with reference to the accompanying drawings, in which:

figure 1 is a perspective view of an exemplary toothbrush accessory according to the present disclosure,

fig. 1A is a perspective view of the exemplary toothbrush attachment of fig. 1, with a portion cut away,

fig. 1B is a perspective view of the exemplary toothbrush accessory of fig. 1, without the tubular housing,

figure 2 is an exploded view of the exemplary toothbrush accessory of figure 1,

figure 3 is a perspective view of a brush assembly in the exemplary toothbrush accessory of figure 1,

figure 4 is a perspective view of the semi-assembled toothbrush accessory of figure 1,

figure 5 is a cross-sectional view of the exemplary toothbrush accessory of figure 1 engaged with a drive output of an exemplary power toothbrush drive unit,

figure 6 is a perspective view of an exemplary toothbrush attachment 200,

figure 6A is an exploded view of the toothbrush attachment 200,

figure 6B1 is a perspective view of the drive coupling assembly of the toothbrush accessory 200,

figure 6B2 is a longitudinal cross-sectional view of the drive coupling assembly of figure 6B1 taken along the flipper,

fig. 7A and 7B are plan and side views of the toothbrush attachment of fig. 6, with the toothbrush head removed,

figure 7A1 is a longitudinal cross-sectional view of the toothbrush attachment of figure 7A as viewed from direction a of figure 7A,

figures 7a2 and 7A3 are longitudinal cross-sectional views taken along line E-E' of figure 7B and viewed from directions B and C respectively,

figures 8A and 8B are perspective and side views of another exemplary drive coupling assembly,

figure 8C is a cross-sectional view taken along the line F-F' of figure 8B and viewed in the direction of the arrows,

FIG. 8D is a sectional view taken along the line G-G' of FIG. 8B and viewed in the direction of the arrows, an

Fig. 9A and 9B are views of the bushing assembly of fig. 8A assembled and semi-assembled to a crank member of a drive coupling assembly.

Detailed Description

As shown in fig. 1, the exemplary toothbrush 100 includes a tubular housing 110 having a first longitudinal end 112 and a second longitudinal end 114, a brush assembly 120 mounted at the second longitudinal end of the tubular housing, and a drive mechanism 180 mounted inside the tubular housing and extending between the first and second longitudinal ends of the tubular housing. As shown in fig. 1A and 1B, the exemplary toothbrush 100 is a toothbrush accessory suitable for use with an electric toothbrush drive unit ("drive handle") having a drive output end. To prepare for use in brushing, the toothbrush attachment is inserted into the axial end of the electric toothbrush drive unit such that the drive mechanism is mechanically coupled with the free axial end of the power output shaft 510 of the drive handle, whereby the rotational or oscillating motion of the motor output shaft is coupled to the drive mechanism 180 and the brush assembly 120.

The tubular housing 110 is rigid and elongated and extends along a longitudinal axis X-X'. The tubular housing optionally has a generally circular cross-section and defines a generally circular aperture along a major portion of its length. The tubular housing 110 has a first longitudinal end 112 ("handle coupling end") for coupling engagement with an electric toothbrush driver, and a second longitudinal end 114 ("bristle carrier end") to which a brush assembly 120 is attached. The bore defined by the hollow housing 110 defines a tapered through passage to form a through channel for a drive mechanism for driving the bristle carrier. The tubular housing 110 and the through passage defined therein gradually decrease in cross-sectional dimension as one extends from the handle attachment end 112 to the bristle carrier end 114.

The brush holder 116 is integrally formed to the tubular housing 110 as an integral extension and extends axially away from the second longitudinal end 114 of the tubular housing 110. The brush holder 116 includes a housing defining a brush receptacle having a receptacle axis. In an exemplary embodiment, for example, in this embodiment, the receptacle axis is substantially orthogonal to the longitudinal axis of the housing. In an exemplary embodiment, an extension of the longitudinal axis X-X' of the tubular housing extends into the receptacle and intersects the receptacle axis. The brush holder 116 includes a main peripheral wall defining a receptacle compartment and an inlet aperture to the receptacle compartment. The peripheral wall includes an inlet portion extending about the brush-receiving portion axis to define a generally circular inlet portion. The inlet portion is a collar portion as follows: having an annular collar wall defining an inlet end. The inlet end of the collar portion is a free end defining a top surface of the brush receptacle. The receptacle axis is also the central axis of the brush receptacle, which is coaxial with the toothbrush axis Y-Y'. The toothbrush axis Y-Y ' intersects the longitudinal axis X-X ' and is orthogonal to the longitudinal axis X-X ' in the exemplary embodiment as in the present embodiment. The brush assembly 120 is mounted on the brush receiving portion and is rotatable relative to the brush receiving portion about a toothbrush axis Y-Y'.

The first longitudinal end 112 of the tubular housing 110 is the handle coupling end of the toothbrush accessory 100 and includes a coupling neck. The coupling neck has an end surface at its longitudinal free end. The end surfaces define a coupling plane and a coupling surface extending substantially parallel to the toothbrush axis Y-Y 'or substantially orthogonal to the longitudinal axis X-X'. The coupling surface is intended to face the drive handle and to be in abutting contact with the drive handle during use. The coupling neck defines an inlet aperture through which a drive shaft 510 of the drive handle enters the tubular housing 110 for mechanical engagement with the drive mechanism.

Referring to fig. 2 and 3, the brush assembly 120 includes a bristle carrier 122 and a plurality of cleaning elements 125 mounted on the bristle carrier 122. The bristle carrier 122 includes a bristle disk 124 and a coupling portion formed on one surface of the bristle disk 124, which is received inside the brush receiving portion and is not mounted with cleaning elements. Bristle discs, also referred to as filament discs, in which the cleaning elements comprise tufts of bristle filaments. A plurality of cleaning elements 125 are mounted on the other free surface of the bristle disc 124 opposite the surface carrying the drive head. The cleaning elements 125 comprise bristle tufts which extend, are distributed and mounted in a direction substantially parallel to the toothbrush axis Y-Y'. In some embodiments, the bristle tufts extend at different angles and/or inclinations and/or orientations relative to the rotational axis of the brush assembly. The bristle disk 124 is generally circular and is also commercially known as a filament disk. The coupling portion is a base portion 126 integrally formed on one surface of the bristle disk 124 opposite the surface carrying the bristles 125. The filament tray includes a top or first surface on which cleaning elements are mounted, a bottom or second surface on which the drive head is formed, and a peripheral wall interconnecting the first and second surfaces. The collar portion of the brush holder surrounds the peripheral wall of the filament disc. In an exemplary embodiment, for example, in this embodiment, the top surface of the filament disk and the top surface of the receptacle are substantially parallel and/or flush.

The brush assembly 120 is rotatably mounted on the toothbrush holder 116 and is rotatable about a brush axis formed by the connecting pin 127. The connecting pin 127 has a pin axis that is aligned with (i.e., coaxial with) the brush axis Y-Y' to define the axis of the brush assembly 120. A pin holder having a pin receiving portion and a pin holder axis is formed in the bottom surface of the brush receiving portion to receive the pin 127. The pin receiver has a pin receiver axis that is coaxial with or defines the brush axis Y-Y'. In an exemplary embodiment, such as in the present embodiment, the pin holder axis is substantially coaxial with the receptacle axis such that the brush assembly 120 is substantially centrally disposed with respect to the brush receptacle.

A guide groove 128 extending in a direction parallel to the toothbrush axis Y-Y' is formed on the base portion 126. A guide slot 128 is formed on a side of the brush assembly 120 proximal to the junction formed by the intersection of the second longitudinal end 114 and the brush holder 116. Guide slot 128 defines a rearward facing drive track that faces the inlet aperture of tubular housing 110 and is in driving engagement with drive member 130.

A guide groove 129 extending in a direction orthogonal to the toothbrush axis Y-Y' is formed on the base portion 126. A guide slot 129 is formed on a side of the brush assembly 120 distal to and opposite from the junction formed by the second longitudinal end 114 intersecting the brush holder 116. The guide pin 117 extends from the brush holder 116 and protrudes into the guide groove 129. The guide slot 129 defines a forward-facing guide track that extends in a direction substantially orthogonal to the rotational axis of the brush assembly 120. The guide slot 129 and guide pin 117 cooperate to form a guide assembly that acts as a secondary guide to mitigate tilting of the brush assembly 120 so as to maintain rotation of the brush assembly 120 about the toothbrush axis Y-Y' during operation. The guide track also acts as a limiting means to limit the maximum angle or range of rotation about the toothbrush axis Y-Y' during operation.

In an exemplary embodiment, for example, in the present embodiment, as shown in fig. 1A and 1B, the drive mechanism 180 includes a crank member 130, a bushing assembly 140, an intermediate shaft 150, and a base support member 160. The crank member 130 includes a first shaft portion 132, a second shaft portion 134 parallel and offset with respect to the first shaft portion 132, and a third shaft portion 136 interconnecting the first and second shaft portions.

In an exemplary embodiment, for example, in the present embodiment, the crank member 130 has two right angle portions extending along its length and located between its longitudinal ends. The first shaft portion 132 is a first axially extending shaft portion coaxial with the power output shaft of the drive handle and/or coaxial with the longitudinal axis X-X'. The second shaft portion 134 is a second axially extending shaft portion and is an eccentric shaft portion with respect to the motor drive shaft axis. The third shaft portion 136 is a crank arm as a transverse shaft portion extending orthogonally to both the first shaft portion and the second shaft portion. The first shaft portion 132 is located proximal to the power take-off shaft and is much longer than the eccentric shaft portion 134, which is located distal to the power take-off shaft or proximal to the brush assembly. In an exemplary embodiment, the first shaft portion is at least twice the length of the second shaft portion.

The bushing assembly 140 has an inner bore coaxial with the longitudinal axis X-X' and defines an elongated passage through which the coaxial shaft portion 132 of the crank member 130 passes and within which the coaxial shaft portion 132 of the crank member 130 is rotatably retained. The bore and the elongated passage are shaped and dimensioned for retaining and maintaining the first shaft portion 132 of the crank member 130 coaxial with the longitudinal axis X-X 'such that the first shaft portion 132 is constrained and supported for rotation about the longitudinal axis X-X' as its axis of rotation during operation. To provide effective coaxial rotational support to the first shaft portion 132 of the crank member 130, the bushing assembly 140 is friction fit within the tubular housing. To mitigate relative rotational and longitudinal movement between the bushing assembly 140 and the tubular housing 110, cooperating stop means are formed on the bushing assembly 140 and the tubular housing 110, respectively. To provide more effective coaxial support to the crank member 130, a bushing assembly 140 is mounted adjacent the crank arm on the first shaft portion 132. The bushing assembly has an outer size and shape that conforms to the inner size of the elongated housing 210 to prevent relative rotational movement.

The bushing assembly 140 includes a first bushing member 142 and a second bushing member 144 that are axially connected. Each of the first and

second bushing members

142 and 144 is made of engineering plastic, such as Polyoxymethylene (POM), suitable for use as a bearing, and includes a solid (solid) body, inside of which an elongated hole is formed for use as a bearing hole. At the respective longitudinal ends of the first and

second bushing members

142, 144, mating coupling means are formed to facilitate detachable connection in a longitudinal direction parallel to the longitudinal axis X-X'. The respective coupling means are eccentrically arranged on the respective end surfaces of the first and

second bushing members

142, 144. In some embodiments, the first and

second bushing members

142, 144 are non-removable, e.g., formed as a unitary or one-piece member, to mitigate operational noise.

The intermediate shaft 150 is a coaxial shaft having a first longitudinal end for detachably coupling with the drive shaft 510 of the drive handle and a second longitudinal end for detachably coupling with the crank member 130 (and more specifically the first shaft portion 132 of the crank member 130). The intermediate shaft 150 includes engagement means at its longitudinal ends to facilitate detachable coupled engagement with the drive handle and crank member 130. The intermediate shaft 150 has a generally circular cross-section, and the circular cross-sectional dimension defining the cross-section of the intermediate shaft 150 gradually decreases as the intermediate shaft 150 extends from the first longitudinal end to the second longitudinal end. The tapered shape of the intermediate shaft 150 facilitates adequate torque transfer and good robustness and durability while reducing material usage. The intermediate shaft 150 is integrally formed from POM. In some embodiments, the crank member 130 is formed and secured within the second longitudinal end of the intermediate shaft 150 by insert molding. In some embodiments, as shown in fig. 5, the first longitudinal end of the intermediate shaft 150 has a receptacle with a shape complementary to the shape of the drive shaft 510 of the power toothbrush drive unit.

The base support member 160 is a rigid hollow structure and includes a first longitudinal end that will be in abutting contact with the drive handle during use and a second longitudinal end that is in coupled engagement with the intermediate shaft 150. The base support member 160 is in the shape of an inverted basket and is integrally formed from ABS. The base support member 160 includes a peripheral wall extending between first and second longitudinal ends and extending about the longitudinal axis X-X' to define a receptacle having an interior compartment for snugly receiving the end portion 520 of the drive handle. The drive shaft 510 is movable relative to the end portion 520 of the drive handle. The base support member 160, and more specifically a first longitudinal end of the peripheral wall of the base support member 160, defines an inlet aperture to the interior compartment of the base support member 160. In some embodiments, the inner surface of the base support member 160 includes a slot or protrusion for receiving the coupling means of the end portion 520 such that relative movement between the accessory 100 and the drive handle is limited.

The peripheral wall is substantially circular, and the diameter of the peripheral wall gradually decreases as the base support member 160 extends from the first longitudinal end to the second longitudinal end. The tapered shape of the base support member 160 contributes to a robust structure while reducing material usage to promote good durability. Two windows 162A, 162B facing at opposite positions and having reduced interference friction are opened in the peripheral wall at positions near the second longitudinal end.

When the brush assembly 120 is properly assembled, the bristle bearing surface of the bristle disk 124 is substantially flush with the upper free end of the brush holder 116, with the base portion 126 within the toothbrush receptacle; the brush assembly 120 is rotatably mounted on the brush holder 116 by a connecting pin 127, and wherein the connecting pin 127 serves as a rotation shaft of the brush assembly 120; the base support member 160 is fixedly mounted on the tubular housing 110 with a first longitudinal end of the base support member 160 outside the tubular housing 110 and in abutting contact with the first longitudinal end 112 of the tubular housing 110; a first longitudinal end of the intermediate axle 150 is seated on a second longitudinal end of the base support member 160 such that the intermediate axle 150 is rotatable relative to the base support member 160 about the longitudinal axis X-X'; a first end of the first shaft portion 132 of the crank member 130 is in coupled engagement with a second longitudinal end of the intermediate shaft 150; also, the free end of the eccentric shaft portion of the crank member 130 is in driving engagement with the brush assembly 120.

When the toothbrush attachment 100 is attached to the drive handle such that the drive shaft 510 of the drive handle is in driving engagement with the intermediate shaft 150, the reciprocating motion of the drive shaft 510 of the drive handle about the longitudinal axis X-X 'will be transmitted to the eccentric shaft portion 134 of the crank member 130 as a reciprocating motion about the longitudinal axis X-X', but with a radius of rotation equal to the vertical separation distance between the center of the coaxial shaft portion 132 and the center of the eccentric shaft portion 134. Due to the driving engagement between the eccentric shaft portion 134 and the brush assembly 120, and more specifically, due to the driving engagement between the eccentric shaft portion 134 and the drive track on the base portion 126 extending along the toothbrush axis Y-Y 'and intersecting the longitudinal axis X-X', the eccentric reciprocating motion of the eccentric shaft portion 134 about the longitudinal axis X-X 'will be transferred to the reciprocating motion of the brush assembly 120 about the toothbrush axis Y-Y'.

As shown in fig. 6, 6A, 6B1, and 6B2, exemplary toothbrush head 200 includes a main housing 210, a brush head 220 having a brush axis Z-Z', and a drive coupling mechanism 280. As shown in fig. 7A and 7B, the main housing 210 includes a neck portion 213 and a head portion 215. The neck portion 213 has a first axial end 214 for detachable attachment with the drive unit, a second axial end 212 in abutment with the head portion, and a tubular housing portion interconnecting the first axial end 214 and the second axial end 212. The drive unit is for example the drive unit of a handheld electric toothbrush drive unit, commonly referred to as a handpiece. The tubular portion extends along a longitudinal axis X-X' between first and second axial ends and defines an elongate bore having a bore axis. The longitudinal axis is the central axis of the tubular portion, along which the tubular portion is substantially laterally symmetrical. The longitudinal axis X-X 'and the brush axis Z-Z' cooperate to define a lateral plane of symmetry. The elongated bore defines a through passage through which the drive coupling mechanism passes. The tubular portion has an elliptical cross-section as it extends along the longitudinal axis X-X' and tapers to narrow as it extends from the first axial end to the second axial end. In this example, the width of the tubular portion, measured laterally (which is orthogonal to the longitudinal axis X-X ' and orthogonal to a lateral plane of symmetry containing the longitudinal axis X-X ' and the brush axis Z-Z '), gradually decreases as the tubular portion extends from the first axial end towards the second axial end. The depth or thickness of the tubular portion, measured in a direction orthogonal to the longitudinal axis X-X' and orthogonal to the lateral direction, gradually decreases as the tubular portion extends from the first axial end towards the second axial end. The rate of decrease in depth is faster than the rate of decrease in width, and the neck portion has a generally circular cross-section at the second axial end. The neck portion has a forward facing edge substantially parallel to the longitudinal axis X-X 'and a rearward facing edge at a substantially constant acute angle relative to the longitudinal axis X-X'. The forward facing edge is the edge on the forward facing side of the neck portion. Toward the front side is the side of the neck portion that has the same orientation as the bristles on the head. The forward edge is the edge on a plane containing the longitudinal axis X-X 'and the brush axis Z-Z'. The rearward edge is located on a diametrically opposite side of the forward edge, and the orientation of the rearward edge is opposite to the orientation of the forward side.

The neck portion comprises a support means 260 for supporting the drive coupling mechanism. The support 260 is a bearing that includes a first axial end, a second axial end, and a peripheral wall extending between the first and second axial ends. An exemplary support device is a plug-like device having a generally cage-like structure. The cage-like support means includes a window portion formed on the peripheral wall. The window portion has a first axial end and a second axial end and includes a plurality of longitudinally extending spacer bars extending between the first and second axial ends.

The first axial end of the support means comprises a circumferential flange portion located outside the neck portion and projecting radially away from the circumferential wall and radially away from the central axis of the support means. The radial extent of the flange portion is greater than or exceeds the radial extent of the internal bore at the first axial end of the neck portion such that the flange portion is blocked by the first axial end of the neck portion and cannot move beyond the first axial end of the neck portion into the neck portion. The flange portion includes a laterally extending flange surface in abutment with the first axial end of the neck portion.

The second axial end of the support means comprises a support portion and a through hole extending through the support portion. The support portion includes a laterally extending support platform on which the coupling end of the coupling shaft portion of the drive coupling mechanism rests. The through-hole is aligned with the drive shaft of the handpiece and permits the drive shaft to extend through the support platform for coupled engagement with the drive coupling mechanism when toothbrush head 200 is mounted on the handpiece.

A latch portion is formed on the support device at a location proximal to the second axial end. The latch portions project radially from the peripheral wall and are in latching engagement with corresponding latch holes or corresponding latch recesses on the tubular portion.

The head portion 215 defines a brush disc holder and has a dome-shaped body with a brush receptacle 216 and a receptacle compartment formed in the interior of the dome-shaped body. The dome-shaped body has a generally hemispherical peripheral wall extending about a central axis and defines an open end portion and a closed end portion. The peripheral wall at the open end portion is substantially circular and centered on a brush axis Z-Z' as a central axis, and defines an open end hole. The peripheral wall tapers as it extends axially away from the open end along the central axis (i.e., away from the front side) to define a circular closed end on the rear side. A connecting hole is formed in the peripheral wall at a connecting portion where the head portion and the neck portion meet. The drive coupling mechanism will extend through the link aperture for coupled driving engagement with the head portion. A shaft retainer 217 is formed on the circular closed end and extends axially from the base of the closed end along the central axis toward the open end. The shaft holder stops below the axial height of the coupling hole.

The brushhead 200 is held on the brush receiving portion and is supported on the brush receiving portion by the brush shaft. The brush shaft defines a brush axis coaxial with the central axis and about which the brush head reciprocally rotates when driven by the drive coupling mechanism during operation. The brush head 220 includes a disk portion having a plurality of bristles formed on one side thereof, forming a plurality of bristle groups called tufts, and a drive engagement portion formed on the other side thereof. The disc portion, also referred to as a filament disc, has a disc axis which is the central axis of the disc portion and which is coaxial with the central axis of the head portion. The exemplary brush head will rotate reciprocally about the disk axis during operation, and the disk axis is at an angle relative to or orthogonal to the central axis of the neck portion. The brush head 220 otherwise has the same description and function as the brush assembly 120, and the description of the brush assembly and the description related thereto are incorporated herein by reference. The bristle filaments may include non-elastomeric bristles (e.g., nylon bristles) and/or elastomeric bristles.

The drive engagement portion is received within the receptacle compartment and includes a shaft receptacle for receiving the brush shaft and a drive slot for engaging a drive end of the drive coupling mechanism. The drive slot is parallel to and offset from the brush shaft and is adapted to engage with the drive end of the drive coupling mechanism such that rotation of the drive end about the rotational axis of the drive coupling mechanism will cause rotation of the brush head about the brush axis and rotation of the brush head about the brush axis will cause upward and downward movement of the drive end along the drive slot. To facilitate driving engagement between the drive engaging portion and the drive coupling mechanism, the drive slot is disposed proximate to and oppositely facing the joint bore.

The drive coupling mechanism includes a coupling portion and a drive portion. The coupling part will receive the driving motion power from the drive unit and will continue to transmit the received driving motion power to the drive part. An exemplary drive motion from the drive unit is a reciprocating rotational motion about a rotational axis of the drive head. To provide sufficient rotational amplitude at the brush head to facilitate effective brushing, the coupling portion includes an eccentric drive member that is displaced radially away from the axis of rotation to provide an amplified rotational amplitude. The exemplary drive portion is a crank shaft 230, the crank shaft 230 including a first shaft portion 232 having a shaft axis, a second shaft portion 234 parallel to and radially displaced from the shaft axis, and an intermediate portion orthogonal to and interconnecting longitudinal ends of the first and second shaft portions. The first shaft portion 232 abuts the coupling portion and has a length that is much longer than the length of the second shaft portion. The intermediate portion has a length equivalent to or smaller than that of the second shaft portion as the eccentric shaft portion. The free longitudinal end of the first shaft portion distal from the second shaft portion 234 is winged to facilitate a more secure driving engagement with the drive portion.

The crankshaft 230 is rotatably retained on a bushing arrangement 240, and the first shaft portion 232 extends through the bushing arrangement 240. The bushing arrangement 240 fits securely inside the neck portion and is prevented from rotating and moving relative to the main housing. During a brushing operation, the first shaft portion 232 of the crank shaft is driven to rotate reciprocally about the shaft axis and relative to the bushing arrangement 240. To facilitate the through-going passage of the first shaft portion 232, the bushing arrangement 240 comprises a through-going hole extending longitudinally through the bushing arrangement and having a hole axis aligned with the rotational axis of the drive unit. During a brushing operation or when in driving engagement, the first shaft portion 232, the through bore of the bushing arrangement, and the drive axis of the handpiece are axially aligned or coaxial.

The coupling portion 250 extends between first and second axial ends and includes a first portion 252 and a second portion 254 extending radially away from the first portion. The first portion is elongate, has a generally circular cross-section along its length, and tapers as it extends from a first axial end abutting the support 260 to a second axial end abutting the crank axle 230. The first portion has a generally bullet shape and has a central axis that is coaxial with a center of a circle defining a circular cross-section of the first portion. The central axis of the first part is aligned with the drive axis of the drive shaft of the drive unit and is thus also the rotational axis of the coupling part.

The second portion is a side portion that includes a flange portion extending radially away from the first portion. The flange portion has a thickness significantly smaller than a thickness or diameter of the first portion, and radially protrudes from a side portion of the first portion as a side fin portion or a side fin portion. The width of the combined first and second part is slightly smaller than the width of the inner bore of the neck part and the coupling part 250 will follow the rotation of the drive unit. The flange portion tapers as it extends from the first axial end to the second axial end to follow the taper of the neck portion.

When assembled, the coupling portion 250 is supported on the support device 260 and abuts the support platform surface of the support device. During a brushing operation, the coupling portion 250 is driven into reciprocating rotation by the drive unit due to the driving engagement between the drive unit and the coupling portion. The coupling portion 250 rotates while abutting against the bearing platform surface of the support device, and the bearing platform surface serves as a bearing surface. Due to the driving engagement between the coupling portion and the driving portion 230, the reciprocating rotation is coupled to the driving portion 230. The amplitude of the reciprocating rotation is amplified by the eccentric second shaft portion 234 and the amplified reciprocating rotation about the axis of rotation of the first shaft portion 232 is converted into reciprocating rotation of the brush head about the brush axis. For example, the bristle disk or brush head will reciprocally rotate at 55 degrees about the brush axis corresponding to 25 degrees of rotation of the first shaft portion 232.

The intermediate shaft 250 is elongated and extends between a first axial end 2501 and a second axial end 2502. The first axial end is a first longitudinal end comprising coupling means for receiving the free end of the power driven shaft 510 of the drive handle. The second axial end is the second longitudinal end located distally of the first longitudinal end and comprises coupling means for receiving the free end of the crank member 230.

The intermediate shaft 250 will serve as a power coupling portion to couple the drive power of the drive unit to the crank member, and includes a main shaft body extending between first and second axial ends. The spindle body has a generally circular outer periphery and the spindle body has a generally circular symmetry along its length. The lateral dimension of the spindle body decreases as it extends from the first axial end to the second axial end such that the spindle body tapers as it extends toward the brush holder. The taper of the main shaft body or countershaft 250 facilitates adequate torque transfer while maintaining good robustness and durability, as well as reducing material usage and reducing the weight of the countershaft 250. The first axial end includes a first bore for receiving a free end of a drive shaft of the handle unit and the second axial end includes a second bore for receiving a free end of the crank member, the first and second bores being coaxial bores and the bores being shaft end receiving bores. Each shaft end receiving bore has a non-circular inner cross-section complementary to the non-circular end of the received shaft end to reduce relative rotation between the received shaft and the main shaft body. The main shaft body is hollow over at least a major part of its length.

The intermediate shaft 250 includes fin members that project radially outward from lateral sides of the main shaft body. The main shaft body and optional intermediate shaft 250 are integrally formed from a high strength plastic such as POM. The radially projecting fin-shaped members will rotate or oscillate with the main shaft body during a brushing operation. The fin-shaped member extends substantially or almost along the entire length of the main shaft body to improve the torque resistance or torque transmission efficiency of the hollow main shaft body. The flipper members have a radial extent that has the added benefit of helping to align and maintain the main shaft body with the drive shaft axis during high speed operation when the main shaft body oscillates at high frequencies. The fin-shaped member further reduces the use of material while providing efficient alignment assistance, torque resistance or transmissibility and/or other benefits of utilizing less material. The radial extent of the flipper member stops short of the inner periphery of the neck portion such that rotational movement of the flipper member is not impeded by the neck portion housing.

A portion of the main shaft body proximal to the first axial end has a cut-out portion. The cutout portion includes a longitudinal cutout portion laterally offset from the spindle body central axis, and a transverse cutout portion extending laterally and radially outward from a longitudinal end of the longitudinal cutout portion distal to the first axial end to form an L-shaped cutout. The L-shaped cut increases the elasticity and flexibility at the base portion of the main shaft body, which is located proximal to the first axial end, to enhance torque transmission performance. An outer portion of the base portion adjacent to and defining the longitudinal cut-out forms a resilient clip for resiliently engaging with an output shaft of the drive unit. The spring clip is formed by the remaining outer portion of the base portion outside the defined longitudinal cut. The remaining part is an upright elongated part which, due to the tapering of the spindle body, is inclined towards the spindle body axis as it extends away from the first axial end or as it extends towards the second axial end to define a resilient clip for engagement with the output shaft end of the drive shaft.

To facilitate driving engagement between the drive unit and the drive coupling mechanism, a drive shaft receiving portion is formed on the first axial end of the coupling portion. The shaft receiving portion may be non-axisymmetric to facilitate a more reliable rotational motion coupling.

To assemble the drive coupling mechanism, a crank shaft is formed. The crankshaft may be formed from a steel pin of substantially uniform cross-section. Next, the first shaft portion of the crankshaft is inserted through the bushing arrangement 240. An exemplary bushing arrangement is a single molded piece made of POM. After the first shaft portion is inserted through the bushing arrangement 240, the free axial end of the first shaft portion 232 of the crankshaft is flattened or laterally enlarged to form a winged end having a greater radial extent than the steel pin or other portion of the crankshaft. Then, the driving part and the coupling part are bonded together, for example, by placing the wing-like end portion into a mold and performing over-molding (over-molding) while the wing-like end portion is in the mold to form the coupling part. As a result, as shown in fig. 6B and 6B1, the coupling portion and the driving portion are integrally formed as a single piece. When assembled on the main housing, the first bend of the crank shaft 230, which is the bend that transitions from the first shaft portion 232, is located proximal to the narrowest end of the neck portion, the second shaft portion 234 is located forward of the first shaft portion 232, and the central axis of the first portion of the coupling axis is located proximal to the rearward facing side of the neck portion.

During operation, the toothbrush attachment is mechanically coupled to the handpiece, and the drive shaft of the handpiece is in driving engagement with the drive coupling mechanism. When in driving engagement, the drive shaft of the handpiece is mechanically coupled with the coupling portion, the central axis of a first portion of the coupling portion is aligned with the shaft axis of the drive shaft, and a second portion of the coupling portion (i.e., the fin portion) is forward of the drive shaft and forward of the axis of rotation of the first portion. As the drive shaft reciprocally rotates about its shaft axis, the coupling portion 250 follows the reciprocal rotation of the drive shaft and reciprocally rotates about a rotation axis Y-Y 'parallel and offset with respect to the longitudinal axis X-X'. The reciprocating rotation of the coupling portion 250 about the axis of rotation drives the crank shaft to also reciprocally rotate about the axis of rotation, and rotation of the crank shaft causes the second shaft portion to reciprocally rotate at an enlarged radius equal to the lateral or vertical separation between the first and

second shaft portions

232, 234 to drive the brush head to reciprocally rotate about the brush axis.

While examples have been described to aid understanding, it will be appreciated that examples are non-limiting examples. For example, although the brush axis Z-Z 'is orthogonal to the longitudinal axis X-X', the brush axis may be at a non-right angle with respect to the longitudinal axis. For example, although the crank shaft has a double right angle portion, the crank or bent portion could have other angles than a right angle without loss of generality.

As shown in fig. 8A-8D, exemplary drive coupling assembly 380 includes a crankshaft 330, a bushing assembly 340, and an intermediate shaft 350. The bushing assembly 340 includes a first bushing member 342 and a second bushing member 344. Crank shaft 330, bushing assembly 340, and countershaft 350 have the same, similar, or equivalent features as described herein, and the associated descriptions of crank

shafts

130, 230,

bushing assemblies

140, 240, and

countershafts

150, 250 are incorporated herein by reference numerals appropriately incremented by 100, where appropriate and/or where the context permits, as necessary for the sake of brevity.

The bushing assembly 340 has a solid body and an elongated hole extending through the solid body, which serves as a support hole through which the crank shaft 330 passes. The bushing assembly 340 has an outer circumferential dimension that conforms to an inner circumferential dimension of an elongated neck portion of the main housing of the toothbrush accessory to prevent relative rotation between the bushing assembly 340 and the neck portion about a longitudinal axis of the neck portion. The outer peripheral dimension here is the dimension of the portion around the longitudinal axis of the neck portion and is the lateral periphery. The bushing assembly 340 has a length comparable to but slightly shorter than the length of the first shaft portion of the crankshaft to facilitate stable rotation or oscillation of the crankshaft relative to the neck portion while permitting rotation of the eccentric shaft portion relative to the solid body. The bushing assembly 340 includes an axially extending groove formed on an outer peripheral surface of a solid body forming the bushing assembly. Each axial groove is a through slot extending from one axial end of the solid body to an opposite axial end to permit the bushing assembly to slide into the neck portion when guided by an axial rib projecting radially from an inner peripheral surface of the neck portion. Axial ribs projecting from the inner surface of the neck portion will engage with the axial ribs to prevent relative rotation of the bushing assembly 340 relative to the neck portion about the neck portion axis. In an exemplary embodiment, for example, in the present embodiment, the bushing assembly 340 has a circumferential dimension comparable to a circumferential dimension of the neck portion.

In the exemplary embodiment, first bushing member 342 and second bushing member 344 are connected by abutting their corresponding inward lateral surfaces and are welded together to form bushing assembly 340, such as by ultrasonic welding. The bearing holes of the bushing assembly 340 are formed by the cooperation of the first and second bushing members. Referring to fig. 8C, 8D, and 9A, the second liner member 344 includes a first lateral portion 3441, a second lateral portion 3442, and a middle portion 3443 interconnecting the first and second lateral portions. The intermediate portion is a laterally indented portion as follows: which cooperate with the first and second lateral portions to define an axial recess that opens facing the first bushing assembly 342. The axial recess has a lateral clearance (clearance) comparable to and slightly larger than the width or lateral dimension of the shaft body to permit rotation relative to the second bushing member 344. The lateral gap is defined by cooperation through respective oppositely facing side walls of the first and second lateral portions. The first and second

lateral portions

3441, 3442 are distributed on opposite sides of the notch and the direction of separation defines the lateral direction herein. The axial recess has a transverse depth comparable to or slightly greater than the width or lateral dimension of the shaft body to permit rotation relative to the second bushing member 344. The transverse direction is orthogonal to the lateral and axial directions.

The first liner member 342 includes a first lateral portion 3421, a second lateral portion 3422, and an intermediate portion 3423 interconnecting the first and second

lateral portions

3421, 3422. The intermediate portion 3423 is a laterally projecting portion that cooperates with the first and second lateral portions to define an axially extending projection that faces the second bushing member 344. The laterally projecting intermediate portion 3423 has a forward or laterally facing surface that cooperates with the intermediate portion 3443 of the second bushing member 344 to define a support aperture.

Mating coupling means 346A, 346B, 348A, 348B are formed on corresponding surfaces of the first and

second bushing members

342, 344 to facilitate connection in a direction orthogonal to the longitudinal axis X-X'. For example, the coupling means includes a lateral projection 346A extending from an end surface of the second bushing member 344, and a lateral hole 346B disposed inside the first bushing member 342 at a location complementary to the lateral projection 346A. When the first and

second bushing members

342, 344 are assembled, the lateral projection 346A is secured within the lateral aperture 346B. The corresponding coupling means may also be a protrusion 348A disposed on the end surface of the second bushing member 344 and a slot 348B disposed at an edge of the first bushing member 342 at a location complementary to the protrusion 348A. While examples have been described to aid understanding, it will be appreciated that these examples are non-limiting examples. For example, both a protrusion and a hole may be provided on a first bushing member, and a corresponding hole and protrusion may be provided on a second bushing member. For example, the projections may be cylindrical, semi-circular or rectangular. For example, only holes or slots are provided on the first or second bushing member. In the case where only the hole is provided, the first bushing member and the second bushing member are assembled along the extending direction of the protruding portion. In the case where only the slot is provided, the protrusion may enter the slot from a plurality of directions, so that the first and second bushing members may be rotatably assembled.

To assemble the drive coupling assembly, the first shaft portion 332 of the crank shaft 330 is inserted over the axial recess of the second bushing member 344. After the first shaft portion 332 has been positioned within the axial recess of the second bushing component 344, the first bushing component 342 is coupled to the second bushing component 344 by way of

mating coupling devices

346A, 346B, 348A, 348B. As a result, the axial recess of the second bushing member 344 is closed by the first bushing member 342. As shown in fig. 9A, the first shaft portion 332 is located forward of the laterally protruding intermediate portion 3423 of the first bushing member 342 and is sandwiched between the first and

second bushing members

342 and 344.

List of reference numerals

Claims

1. A toothbrush accessory for detachable attachment to a motor drive unit of an electric toothbrush, wherein the motor drive unit comprises a motor and a drive shaft driven by the motor to reciprocally rotate about a rotational axis of the drive shaft, the toothbrush accessory comprising: a main housing including a tubular neck portion having a longitudinal axis and a head portion defining a toothbrush receiving portion; a brush assembly (120) including a brushhead rotatably mounted on the toothbrush receiving portion of the head portion and a rotatable brush axis; and a drive coupling mechanism mounted inside the neck portion and having an axis of rotation;

the drive coupling mechanism includes a crankshaft, a bushing arrangement and a coupling shaft portion;

the coupling shaft portion including, at an axial free end portion, engagement means adapted to be brought into detachably coupled driving engagement with the drive shaft of the motor drive unit to receive rotary drive power from the drive shaft and to transmit the received rotary drive power to the crank shaft,

a crank shaft for driving the brushhead to rotate reciprocally about the brush axis, the crank shaft including a first shaft portion (232) aligned with the axis of rotation and an eccentric shaft portion (234) offset with respect to the axis of rotation, the first shaft portion passing through the bushing arrangement, the eccentric shaft portion being in driving engagement with the brush assembly (120);

the coupling shaft portion includes an axisymmetric first portion that tapers as it extends toward the head portion; and is

The coupling shaft portion and the crank axle are integrally formed as a unitary member and the crank axle is rotatably mounted on the bushing arrangement.

2. The toothbrush attachment of claim 1, wherein the coupling shaft portion includes a non-axisymmetric second portion that is a side portion that projects radially outward from the axisymmetric first portion; and the axisymmetric first portion has a longitudinal center axis aligned with the rotational axis.

3. A toothbrush attachment as claimed in claim 2, wherein the axisymmetric first portion has a circular cross-section which tapers in size as it extends toward the head portion.

4. The toothbrush attachment of claim 2, wherein the side portion includes a finned flange portion having a radial extent from the axisymmetric first portion and tapering as it extends axially toward the head portion.

5. A toothbrush attachment as claimed in claim 4, wherein the neck portion includes a forward-facing edge and a rearward-facing edge, the forward-facing edge and the rearward-facing edge lying on a plane containing the rotational axis and the brush axis, and the neck portion being laterally symmetrical about the plane; and, the fin flange portion is located proximal to the forward edge, and the axisymmetric first portion is located proximal to the rearward edge.

6. The toothbrush attachment of any preceding claim, wherein the crank shaft (230) comprises a first shaft portion (232) aligned with the rotational axis and a second shaft portion being an eccentric shaft portion (234), the eccentric shaft portion (234) being parallel and offset with respect to the rotational axis; the neck portion includes a forward-facing edge and a rearward-facing edge, the forward-facing edge and the rearward-facing edge lie on a plane containing the axis of rotation and the brush axis, and the neck portion is laterally symmetric about the plane; and, the axis of rotation is located proximal to the rearward facing edge, and the eccentric shaft portion is located proximal to the rearward facing edge.

7. A toothbrush accessory as claimed in claim 6 wherein said neck portion has an elliptical cross-section relative to said longitudinal axis of said neck portion and said axis of rotation is parallel to said forward facing edge and at a small acute angle relative to said rearward facing edge.

8. A toothbrush accessory according to claim 6, wherein said crank shaft (230) comprises an enlarged wing at a free axial end of said first shaft part (232) and said enlarged wing is embedded inside said coupling shaft part by over-moulding.

9. A toothbrush accessory according to claim 8 wherein said bushing means is a unitary device extending between two axial ends and having a longitudinally extending through bore extending between said two axial ends, and said wing portion has a radial extent exceeding a gap of said through bore.

10. The toothbrush attachment of claim 1, wherein the neck portion includes a bearing (260) having a bearing platform surface on which the drive coupling mechanism is rotatably supported, the bearing (260) being a bearing including a first axial end, a second axial end, and a peripheral wall extending between the first and second axial ends; also, the support device has a cage-like structure.

11. A toothbrush head for attachment to an output drive shaft of a drive handle of a power toothbrush, the toothbrush head comprising a tubular housing, a bristle carrier-containing brush assembly (120) and a crank member: the tubular housing extending along a longitudinal axis, the bristle carrier being mounted at or near a longitudinal end of the tubular housing and rotatable about a carrier axis, and the crank member extending inside the tubular housing to transmit drive rotation from the driven end to the driving end; the drive end portion is offset relative to the driven end portion; the crank member is supported for rotation within the tubular housing by a bushing assembly, the bushing assembly including a first bushing member and a second bushing member, the bushing assembly being rotatably fixed on the crank member; the crank member includes a first shaft portion (232) aligned with the axis of rotation and an eccentric shaft portion (234) offset from the axis of rotation, the first shaft portion passing through the bushing assembly, the eccentric shaft portion in driving engagement with the brush assembly (120).

12. A toothbrush head according to claim 11 wherein the crank member passes through an aperture in the first bushing member, the aperture having a diameter less than the offset distance to prevent the driven end from passing through the first bushing member, the bushing assembly being rotatably secured to the crank member when the second bushing member is mounted to the crank member.

13. A toothbrush head according to claim 12 wherein the second bushing member includes a slot along the longitudinal axis for detachably connecting to the crank member.

14. A toothbrush head according to claim 11 wherein the crank member is a straight metal rod that is bent to form a first shaft portion, a second shaft portion, and a crank arm interconnecting the first and second shaft portions.

15. A toothbrush head according to claim 14 wherein the first shaft portion and the crank arm are at right angles; the crank arm and the second shaft portion are at right angles.

16. A toothbrush head according to claim 14 wherein the first bushing member is movable along the first shaft portion and stops at the crank arm when the second bushing member is detached from the crank member.

17. A toothbrush head according to claim 11 wherein the toothbrush head includes an intermediate shaft that is a coaxial shaft and has a first longitudinal end for detachably coupling with the output drive shaft of the drive handle and a second longitudinal end that is fixed to the crank member.

18. A toothbrush head according to claim 17 wherein the intermediate shaft is secured to the crank member by insert molding.

19. A toothbrush head according to claim 17 wherein the second bushing member includes a slot along the longitudinal axis for detachably connecting to the crank member at a location between the intermediate shaft and the first bushing member.

20. A toothbrush head according to any preceding claim wherein the toothbrush head comprises a base support member fixedly mounted on the tubular housing, the base support member comprising a peripheral wall extending between first and second longitudinal ends and about the longitudinal axis to define a receptacle having an internal compartment for receiving a portion of the output drive shaft of the drive handle in a close fit; the peripheral wall is perforated with at least one window to reduce an interference area between the base support member and the drive handle.

21. A toothbrush head according to claim 20 wherein the peripheral wall defines opposed windows.

22. A toothbrush head according to claim 11 wherein the crank member passes through a groove of the first bushing member, the crank member being prevented from exiting the groove when the second bushing member is mounted to the first bushing member.

23. A toothbrush head according to claim 12 wherein the second bushing member is provided with a coupling means and the first bushing member is provided with a corresponding coupling means such that when the coupling means is engaged with the corresponding coupling means, the second bushing member is fixedly mounted to the first bushing member.

24. A toothbrush head according to claim 11 wherein the bristle carrier includes a guide slot extending in a direction parallel to the carrier axis.