U.S. patent application number 11/747267 was filed with the patent office on 2007-12-27 for electric toothbrush with skewed neck.
This patent application is currently assigned to WONG'S SPRINGS INDUSTRIAL LIMITED. Invention is credited to Thomas Hai Wang.
Application Number | 20070294847 11/747267 |
Document ID | / |
Family ID | 36803716 |
Filed Date | 2007-12-27 |
United States Patent
Application |
20070294847 |
Kind Code |
A1 |
Wang; Thomas Hai |
December 27, 2007 |
ELECTRIC TOOTHBRUSH WITH SKEWED NECK
Abstract
An elongate neck of a toothbrush extends askew to an elongate
handle which encloses a rotary motor. At the end of the neck is a
head to which brush blocks are mounted for movement relative to the
head. The transmission includes a driving member and a driven
member for transmitting torque from the motor, the driving member
rotating about a driving member axis, and the driven member
rotating about a driven member axis. A crankshaft mounted to the
head converts rotation of the driven member to movement of a brush
block, the driven member axis is skewed or offset relative to the
driving member axis, and the driving member and the driven member
are connected by a helical spring flexible coupling. One brush
block rotates in an oscillating manner and a pair of brush blocks
oscillate, in a linear manner, 180 degrees out of phase.
Inventors: |
Wang; Thomas Hai; (Hong
Kong, CN) |
Correspondence
Address: |
LEYDIG VOIT & MAYER, LTD
700 THIRTEENTH ST. NW, SUITE 300
WASHINGTON
DC
20005-3960
US
|
Assignee: |
WONG'S SPRINGS INDUSTRIAL
LIMITED
Hong Kong
CN
|
Family ID: |
36803716 |
Appl. No.: |
11/747267 |
Filed: |
May 11, 2007 |
Current U.S.
Class: |
15/22.2 ;
15/22.1 |
Current CPC
Class: |
A61C 17/222 20130101;
A61C 17/3454 20130101; A61C 17/349 20130101; A61C 17/3436
20130101 |
Class at
Publication: |
15/22.2 ;
15/22.1 |
International
Class: |
A46B 13/02 20060101
A46B013/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 22, 2006 |
GB |
0612398.8 |
Claims
1. An electric toothbrush comprising: an elongate handle enclosing
a rotary motor; an elongate neck extending askew to the handle and
having a head at a distal end of the neck; at least one brush block
mounted to the head for movement relative to the head; a
transmission including a driving member connected to a driven
member for transmitting torque from the motor, the driving member
rotating about a driving member axis, the driven member rotating
about a driven member axis; a helical spring flexible coupling
connecting the driving member to the driven member; and a
conversion mechanism mounted to the head for converting rotation of
the driven member into movement of the brush block, wherein the
driven member axis is skewed or offset relative to the driving
member axis.
2. The toothbrush of claim 1 including fastening means at a
proximal end of the neck for releasably fastening the neck to the
handle.
3. The toothbrush of claim 2 wherein the fastening means is a
bayonet coupling fastening the neck to the handle by a push-turn
action.
4. The toothbrush of claim 1 wherein the driving member is mounted
at a proximal end, the driven member is mounted in the head, and
the helical spring flexible coupling is elongated to extend within
the neck between the driving and driven members.
5. The toothbrush of claim 4 wherein the helical spring flexible
coupling has a substantially cylindrical body with outwardly
tapered frusto-conical ends for receiving cooperating tapered
portions of the driving and driven members in a push fit.
6. The toothbrush of claim 5 wherein the transmission further
includes a gearbox for increasing the torque applied to the driving
member and reducing speed of rotation of the driving member, axes
of the motor, the gearbox, and the driving member being coaxial
with a central longitudinal axis of the handle.
7. The toothbrush of claim 6 wherein the conversion mechanism
comprises a crankshaft.
8. The toothbrush of claim 7 including at least one sliding brush
block mounted for linear sliding movement relative to the head and
at least one rotary brush block mounted to rotate relative to the
head.
9. The toothbrush of claim 8 including three brush blocks mounted
to the head for separate oscillatory movement relative to the head,
the brush blocks including a pair of sliding brush blocks and one
rotary brush block.
10. The toothbrush of claim 9 wherein the crankshaft is connected
to the driven member coaxially, each sliding brush block is mounted
for sliding movement substantially perpendicular to the driven
member axis, each rotary brush block is mounted for rotation about
a respective rotary block axis substantially perpendicular to the
sliding block axis, and the crankshaft has an eccentric throw for
engaging each sliding and rotary brush block.
11. The toothbrush of claim 10 wherein each sliding block throw is
received in an aperture in a respective sliding brush block, the
aperture extending substantially parallel to an axis of the
crankshafts, and each rotary brush block throw is received in a
slot in the rotary brush block, the slot extending substantially
parallel to a rotary brush block axis.
12. The toothbrush of claim 11 wherein the neck is curved.
13. A replaceable brushing attachment comprising: an elongate
hollow neck having a proximal end with means for releasably
fastening to a handle enclosing a rotary motor, the neck further
having a head on a distal ends of the neck; at least one brush
mounted to the head for movement relative to the head; a
transmission enclosed substantially within the neck, the
transmission including a driving member joined by a connector to a
driven member for transmitting torque from the motor, the driving
member rotating about a driving member axis, the driven member
rotating about a driven member axis; a conversion mechanism mounted
to the head for converting rotation of the driven member into
movement of the brush, wherein the driven member axis is skewed or
offset relative to the driving member axis, and the connector
comprises a helical spring flexible coupling.
14. The replaceable brushing attachment of claim 13 including
fastening means at a proximal end of the neck for releasably
fastening to the handle.
15. The replaceable brushing attachment of claim 14 wherein the
fastening means is a bayonet coupling, fastening the neck to be the
handle by a push-turn action.
16. The replaceable brushing attachment of claim 14 wherein the
driving member is mounted at a proximal end, the driven member is
mounted in the head, and the helical spring flexible coupling is
elongated to extend within the neck between the driving and driven
members.
17. The replaceable brushing attachment of claim 16 wherein the
helical spring flexible coupling has a substantially cylindrical
body with outwardly tapered frusto-conical ends for receiving
cooperating tapered portions of the driving and driven members in a
push fit.
18. The replaceable brushing attachment of claim 17 wherein the
conversion mechanism comprises a crankshaft.
19. The replaceable brushing attachment of claim 18 including at
least one sliding brush block mounted for linear sliding movement
relative to the head and at least one rotary brush block mounted to
rotate relative to the head.
20. The replaceable brushing attachment of claim 19 including three
brush blocks mounted to the head for separate oscillatory movement
relative to the head, the brush blocks including a pair of sliding
brush blocks and a one rotary brush block.
21. The replaceable brushing attachment of claim 20 wherein the
crankshaft is connected to the driven member coaxially, each
sliding brush block is mounted for sliding movement substantially
perpendicular to the driven member axis, each rotary brush block is
mounted for rotation about a respective rotary brush block axis
substantially perpendicular to the sliding block axis, and the
crankshaft has an eccentric throw for engaging each sliding and
rotary brush block.
22. The replaceable brushing attachment of claim 21 wherein each
sliding block throw is received in an aperture in a respective
sliding brush block, the aperture extending substantially parallel
to an axis of the crankshafts, and each rotary brush block throw is
received in a slot in the rotary brush block, the slot extending
substantially parallel to a rotary brush block axis.
23. The replaceable brushing attachment of claim 22 wherein the
neck is curved.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to electric toothbrushes
having an oscillating brush block with an elongate handle and neck,
the neck being skewed relative to the handle. More particularly,
the invention relates to electric toothbrushes wherein the
transmission includes two rotating members with skewed axes of
rotation to accommodate the skew between the handle and neck.
[0002] Some known electric toothbrushes have a brush block driven
to oscillate by a rotating drive shaft. Typically the drive shaft
is coaxial with a motor and gearbox and is elongated to extend
through the neck of the toothbrush or replaceable brushing
attachment. The handle is elongate, encloses the motor and gearbox,
and the neck extends parallel to the handle. The transmission may
have an eccentric that fits into a slot formed in the brush block
to cause the oscillation. It would be advantageous however, for
ergonomic reasons, that the neck be skewed relative to the handle,
and doing so creates difficulties with a transmission of this type
due to the angle through which the torque must be transmitted.
While a bevel gear drive can be used to connect two members when
their axes of rotation are skewed, this arrangement is relatively
costly to manufacture and so is particularly disadvantageous when
this part of the transmission is mounted in a replaceable brushing
attachment.
[0003] It is an object of the present invention to provide an
improved electric toothbrush of the type having an elongate handle
and neck skewed relative to one another, the handle and neck
enclosing a transmission connecting a rotary motor to an
oscillating brush block wherein the transmission includes two
rotating members with skewed or offset axes of rotation to transmit
torque between the skewed handle and neck.
[0004] It is a further object of the present invention to provide
an improved replaceable brushing attachment having an elongate neck
adapted to extend askew to a handle to which it may be releasably
connected.
DISCLOSURE OF THE INVENTION
[0005] According to one aspect of the invention there is provided
an electric toothbrush comprising:
an elongate handle enclosing a rotary motor; an elongate neck
extending askew to the handle and having a head at a distal end
thereof; at least one brush block mounted to the head for movement
relative thereto; a transmission including a driving member
connected to a driven member for transmitting torque from the
motor, the driving member rotating about a driving member axis, the
driven member rotating about a driven member axis; a conversion
mechanism mounted to the head and adapted for converting rotation
of the driven member to movement of the brush block, wherein the
driven member axis is skewed or offset relative to the driving
member axis, and the driving member and driven member are connected
by a helical spring flexible coupling.
[0006] The helical spring flexible coupling is able to transmit the
torque while accommodating skew (i.e. angular misalignment) and/or
offset (i.e. parallel misalignment) between the drive and driving
member axes, and thus allows a toothbrush of this type to be
manufactured more cost effectively. The coupling may possibly also
accommodate a degree of end float or axial misalignment between the
driving and driven members.
[0007] The neck is releasably attachable to the handle, having
means at a proximal end thereof for fastening to the handle.
Preferably the fastening means is a bayonet coupling, allowing the
neck to be fastened by a push-turn action.
[0008] Preferably the driving member is mounted at the proximal end
and the driven member mounted in the head, the helical spring
flexible coupling being elongated to extend within the neck between
the driving and driven members.
[0009] The helical spring flexible coupling preferably has a
substantially cylindrical body with outwardly tapered
frusto-conical ends adapted to receive cooperating tapered portions
of the driving and driven members in a push fit.
[0010] The transmission preferably further includes a gearbox for
increasing the torque applied to the driving member and reducing
its speed of rotation, the axes of the motor, gearbox and driving
member being coaxial with a central longitudinal axis of the
handle.
[0011] In the preferred embodiment three brush blocks are mounted
to the head for separate oscillatory movement relative thereto, the
conversion mechanism comprising a crankshaft, the brush blocks
including a pair of sliding brush blocks mounted for linear sliding
movement relative to the head and a rotary brush block mounted to
rotate relative to the head.
[0012] The crankshaft is preferably connected to the driven member
with which it is connected coaxially, each sliding brush block
being mounted for sliding movement substantially perpendicular to
the driven member axis, each rotary brush block being mounted for
rotation about a respective rotary block axis substantially
perpendicular to the sliding block axis, the crankshaft having an
eccentric throw for engaging each brush block.
[0013] Each sliding block throw is received in an aperture in the
sliding block which extends substantially parallel to the
crankshaft axis, and each rotary block throw is received in a slot
in the rotary block which extends substantially parallel to its
respective rotary block axis.
[0014] In another aspect the invention provides a replaceable
brushing attachment comprising:
an elongate hollow neck having a proximal end with means for
releasably fastening to a handle enclosing a rotary motor, the neck
further having a head on a distal end thereof; at least one brush
mounted to the head for movement relative thereto; a transmission
enclosed substantially within the neck, the transmission including
a driving member joined by a connector to a driven member for
transmitting torque from the motor, the driving member rotating
about a driving member axis, the driven member rotating about a
driven member axis; a conversion mechanism mounted to the head and
adapted for converting rotation of the driven member to movement of
the brush, wherein the driven member axis is skewed or offset
relative to the driving member axis, and the connector comprises a
helical spring flexible coupling.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Preferred forms of the present invention will now be
described by way of example with reference to the accompanying
drawings, wherein:
[0016] FIG. 1 is a plan view of a toothbrush according to the
invention,
[0017] FIG. 2 is transverse cross-section (along line AA) of the
toothbrush of FIG. 1,
[0018] FIG. 3 is a plan view of the neck or replaceable brushing
attachment of the toothbrush of FIG. 1 shown separated from the
handle,
[0019] FIG. 4 is transverse cross-section (along line AA) of the
neck or replaceable brushing attachment of FIG. 3,
[0020] FIG. 5 is cross-section (along line CC) of FIG. 4,
[0021] FIG. 6 is transverse cross-section (along line DD) of FIG.
4,
[0022] FIG. 7 is transverse cross-section (along line EE) of FIG.
4,
[0023] FIG. 8 is transverse cross-section (along line FF) of FIG.
4, and
[0024] FIG. 9 is transverse cross-section of the handle of the
toothbrush of FIG. 1 shown separated from the neck or replaceable
brushing attachment, and
[0025] FIG. 10 is transverse cross-section (along line BB) of FIG.
9.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0026] Referring to FIGS. 1 and 2, the electric toothbrush 1
includes a handle 2 having a longitudinal axis 3 and an elongate
neck 4. The handle 2 includes hollow casing part 7a at one end of
which is fixed casing part 7b and to which the neck 4 is fixed at
the opposing tapered end 8. Enclosed in the handle 2 are two
batteries 9, rotary motor 10 and gearbox 11, the axes of both the
motor 10 and gearbox 11 being coaxial with a central longitudinal
axis 3. At a distal end 5 of the neck 4 is a head 12 to which brush
blocks 13, 14 and 15 are mounted. The brush blocks 13, 14 and 15
have bristles 18, the ends of which define a tooth-contacting plane
(indicated generally by the dashed line 19). The neck 4 is skewed
relative to the handle, the longitudinal axis of the neck being
curved, relative to the axis 3, in a plane substantially
perpendicular to the tooth-contacting plane 19, smoothly curving
between the proximal end 6 and the distal end 5 through an angle 17
of 20.degree.
[0027] As best seen from FIGS. 3 and 4, the neck 4 is detachable
from the handle to provide a replaceable brushing attachment. The
means for fastening the handle 2 and neck 4 is a bayonet coupling.
At the proximal end 6 is a cylindrical portion 20 in which two
L-shaped slots are formed, each having an axial portion 21 and
circumferential portion 22 for cooperating with a nub 43, 44
provided on the handle 2 (as described below). At the end of each
circumferential portion 22 is a radially extending protrusion
39.
[0028] Received in a journal 23 mounted inside the proximal end 6
is a driving member 23 which rotates about a driving member axis
25, which is coaxial with the central longitudinal axis 3 when the
handle and neck are assembled. The inner end 27 of the driving
member 23 is tapered and the opposing end is attached to a first
part 28 of a connector, the first part having an outer end 29 which
is cross-shaped in transverse section.
[0029] The driven member 30 is fixed inside the head 12 and rotates
about a driven member axis 32 both skewed and offset relative to
the driving member axis 25.
[0030] The helical spring flexible coupling 33 is elongated to
extend within the neck 4 to provide a torsional coupling between
the driving and driven members 24, 30. The flexible coupling 33 is
relatively stiff torsionally, being closely wound with adjacent
coils abutting. The helical spring flexible coupling 33 has a
cylindrical body with frusto-conical ends 34, 35 opening outwardly
to receive the tapered ends 27, 30 of the driving and driven
members in a push fit.
[0031] The conversion mechanism for converting rotation of the
driven member 30 to movement of the brush blocks 13, 14, 15
includes a crankshaft 36 fixed to the driven member 30, The
crankshaft 36 is mounted by coaxial journals 31, 37 and 38 spaced
at intermediate positions along its length to rotate about the
driven member axis 32. The axis 32 of the driven member and
crankshaft 36 is inclined at an angle 50 of approximately
10.degree. relative to the central longitudinal axis of the
flexible coupling 33.
[0032] Referring to FIGS. 5-8, the rotating brush block 13 is
mounted to rotate about an axis 50 perpendicular to the crankshaft
axis 32. A rotary block eccentric throw 51 formed on the end of
crankshaft 36 is received in a slot 52 parallel to axis 50 to
oscillate the block 13.
[0033] Both the sliding brush blocks 14, 15 are received in the
head to reciprocate transversely in direction 55. The throw 53
nearest the driven member 28 and the throw 54 are both circular in
cross-section and received in an aperture 56 which extends
perpendicular to the crankshaft axis 32 and to direction 55, A
throw 54 for driving the sliding block 14 is 180 degrees out of
phase with the throw 53 for driving the block 15, oscillating the
blocks in opposing directions.
[0034] At the end of the handle 2 is a recess with cylindrical
walls 45 for receiving the end portion 20. Opposing nubs 43, 44
project inwardly from the walls 45. In use, when the handle is
grasped with the user's thumb projecting toward the head 12 and
resting over the switches 41, 42 for controlling the motor 10, then
the neck 4 is skewed for best ergonomic positioning. To ensure the
neck 4 cannot be angularly misaligned when fixed to the handle 2,
the nub 43 is longer circumferentially than the nub 44, each being
received in an axial portion 21 which is correspondingly wider. The
nubs 43, 44 ride over the respective protrusions 39 which thereby
provide a detent action, holding the head in position.
[0035] At the inner end of the recess is a second part 46 of a
connector, for cooperating with the first part 28 having an outer
end 47 having a cross-shaped recess to receive the end 29. The
second part 46 is fixed in a bearing 48 to rotate with the gearbox
output shaft 49 with which it is coaxially mounted, together with
the motor 10.
[0036] Aspects of the present invention have been described by way
of example only and it should be appreciated that modifications and
additions may be made thereto without departing from the scope
thereof.
* * * * *