Note: Descriptions are shown in the official language in which they were submitted.
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Toothbrush and Attachment Therefor
This invention relates to an electric toothbrush having a handpiece and an
attachment
mountable thereon. The present invention relates in particular to the
attachment for such an
electric toothbrush, including a working head and a tubular coupling member
which is joined to
the working head and mountable on a toothbrush handpiece, with a plug-on shaft
for driving the
working head being provided in the coupling member and having a coupling
contour for
coupling by positive engagement with a drive shaft provided on the toothbrush
handpiece. In
addition, the present invention also relates to said toothbrush handpiece,
which has a drive
shaft insertable into the plug-on shaft of the attachment with a snug fit.
Said attachment can be
in particular an attachment brush for dental cleansing, but interproximal
cleaning devices, gum
massage heads or other attachment tools for performing similar tasks in the
oral cavity can also
be contemplated.
From EP 0 500 537 Bl there is known an electric toothbrush on which the
attachment brush is
connected on the one hand to a front-end shank part of the toothbrush
handpiece and on the
other hand to a drive shaft projecting therefrom. For this purpose the
attachment brush has
radially resilient detent hooks which can be locked in place in corresponding
detent notches on
the handpiece.
From DE 103 52 993 Al there is known in addition an electric toothbrush on
which the
attachment brush is fixed only directly to the drive shaft which projects at
the front end out of
the toothbrush handpiece. For this purpose the attachment brush has a coupling
member with
an inner recess of the blind-hole type into which an on the whole sleeve-
shaped mount is
inserted. Said mount, into which the drive shaft can be inserted with a snug
fit, includes several
spring elements which are radially resilient and intended to ensure a zero-
play connection
between the attachment brush and the drive shaft.
For securing the attachment to the toothbrush handpiece housing stub
projecting at the front
end, it is also known to simply push the tubular coupling member of the
attachment onto the
stub with force until it is firmly clamped in place by frictional engagement
therewith. To prevent
the connection becoming separated due to the vibrations of the electric
toothbrush drive and
the forces applied by brushing, it is necessary however to use a very slight
taper to effect self-
locking of the clamp mechanism. On the other hand it would be desirable to
provide a more
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pronounced taper on the stub or neck of the toothbrush handpiece and,
complementary thereto,
on the attachment in order to be able to obtain a connection permitting more
lenient tolerances.
Basically the same applies to the connection between the drive shaft of the
handpiece and the
plug-on shaft of the attachment. Here, too, it would be desirable to provide a
more pronounced
taper on the coupling contour of the drive shaft and, complementary thereto,
on the plug-on
shaft of the attachment in order to be able to obtain a connection which
allows more lenient
tolerances.
Based on this realization, it is an object of the present invention to provide
an improved
toothbrush, an improved toothbrush handpiece and an improved attachment
therefor, which
prevent the disadvantages of the prior art while developing the art further in
advantageous
manner. In particular it is an object to provide an easy-to-couple connection
between the plug-
on shaft of the attachment and the drive shaft of the toothbrush handpiece,
which is insensitive
to tolerances, couples the two sections of the drive train preferably with
zero play, and yet can
be released and re-established again in easy manner. Preferably, it is
desirable for the
attachment to be suitable for use with different toothbrush handpieces with
different drive shaft
configurations.
According to the present invention, this object is accomplished by an
attachment according to
claims 1, 15 and 19, a toothbrush handpiece according to claim 23 and a
toothbrush according
to claim 27. Preferred embodiments of the invention are the subject-matter of
the dependent
claims.
It is proposed therefore in one aspect of the present invention to provide on
the attachment a
coupling part which is axially movable in the attachment longitudinal
direction and to convert its
axial movement into an unlocking or locking movement of the coupling of the
drive train in a
direction transverse to the attachment longitudinal direction. This enables,
on the one hand, a
firm and also vibration-resistant connection to be obtained between the
attachment and the
toothbrush handpiece, while on the other hand enabling the connection to be
released and re-
established by the axial push-on and pull-off movement known in the art.
According to the
present invention, a transversely movable engagement part of the coupling
contour of the plug-
on shaft of the attachment and/or an actuating part provided on the coupling
member of the
attachment are movable in the attachment longitudinal direction, with the
engagement part
being engageable with the actuating part such that a movement of the actuating
part and/or of
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the engagement part in the attachment longitudinal direction produces an
unlocking or locking
movement of the engagement part in a direction transverse to the attachment
longitudinal
direction. If the coupling contour of the plug-on shaft of the attachment is
locked onto the drive
shaft of the toothbrush handpiece, first the attachment or an actuating part
connected thereto is
moved axially substantially in the attachment longitudinal direction relative
to the locked
coupling contour, whereby the engagement part of the coupling contour unlocks
itself in a
direction transverse to the toothbrush longitudinal direction to enable the
plug-on shaft to be
pulled together with the attachment off the drive shaft of the toothbrush
handpiece. This
attaching or connecting mechanism permits even non-self-locking connecting or
faying
contours, in particular those with a more pronounced taper, to be provided at
the interface of
the drive train because fixedly securing is assured nevertheless by the
locking movement which
takes place in a direction transverse to the attachment longitudinal
direction. In particular the
interface of the drive train, which otherwise is problematic in this respect,
can thus be rendered
insensitive to tolerances.
To achieve simple operation of the attachment and be able to pull the
attachment off the
toothbrush handpiece as easily as heretofore possible, a further aspect of the
invention
provides for the actuating part to have an unlocking section which is arranged
and configured
such that during an axial movement of the actuating part away from the working
head the
unlocking section is movable into engagement with the engagement part of the
plug-on shaft
and forces the engagement part into an unlocked position. In other words, the
actuating part is
arranged and configured such that the actuating part automatically unlocks the
coupling insert
when the attachment is being pulled off the toothbrush handpiece.
According to a preferred embodiment of the invention, a wedge-shaped surface
may be
provided on the engagement part of the coupling contour of the plug-on shaft
and/or the
actuating part, which surface produces the desired unlocking movement while
the engagement
part rides over the actuating part. A pair of plane wedge-shaped surfaces may
be provided, but
it is also possible to use a pair of beveled surfaces arched in a spherical or
concave
configuration in the manner of a cam or a cam-type control surface on the one
hand and an
actuating member riding over it on the other hand, which, while the engagement
part rides over
the actuating part as a result of the axial relative movement, converts said
axial movement into
an unlocking movement in a direction transverse to the axial direction.
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It is also generally possible, in reversal of the kinematics, to provide for
the actuating part to
effect not the unlocking but the locking of the coupling contour of the plug-
on shaft or the
engagement part connected thereto. In this case the engagement part in its
initial position may
adopt, or be biased into, a non-locking position. When the attachment is
plugged onto the
toothbrush handpiece, the engagement part of the coupling is forced into its
locking position by
way of the actuating part. Preferred however is the previously described
embodiment of the
invention according to which the coupling contour of the plug-on shaft is
configured to be self-
locking and the locking, which occurs on its own while the attachment is being
seated onto the
toothbrush handpiece, is then released by means of the actuating part while
the attachment is
being removed again.
In a particularly advantageous embodiment of the invention, the engagement
part may form a
spring catch and/or a detent clip which, while the coupling member is being
plugged onto the
toothbrush handpiece, slides along the connecting member of the drive shaft of
the toothbrush
handpiece, rebounds elastically in the process and, upon reaching the fully
plugged-on position,
snaps into place by positive engagement. When the attachment is to be removed
again from
the toothbrush handpiece, the spring catch or detent clip is unseated from its
snapped-in
position by an axial relative movement between the actuating part and the
spring catch or
detent clip.
Generally, the engagement part may be configured in a variety of ways.
According to an
advantageous embodiment of the invention, the engagement part may have a
detent contour in
particular in the form of a detent hook, which is provided on the protruding
end of an
engagement finger advantageously resilient and/or pivotal about a transverse
axis and is
radially movable by the actuating part. Advantageously, the at least one
engagement finger
may be integrally made of one piece with the body of the coupling section of
the plug-on shaft
and be separated from the rest of the body for example by longitudinal slits
in order to be
resilient in relation to the remaining body. The engagement finger may also be
part of a
separate coupling attachment secured to the plug-on shaft.
Alternatively or in addition, an engagement part may also be provided in the
form of a rocker
which at its one end has a suitable detent contour, in particular in the form
of a detent hook for
locking engagement with the toothbrush handpiece, and at its other end forms
an actuating
section which is movable into engagement with the aforementioned actuating
part. In this case,
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too, the engagement part may be integrally made of one piece with the body of
the coupling
insert, in particular by way of a flexible connecting bar in the middle
section of the
aforementioned rocker.
Another advantageous embodiment of the invention may comprise a slotted detent
ring on the
plug-on shaft, which ring is radially compressible and extensible. Compression
can be
accomplished particularly by biasing the detent ring, while conversely an
extension or widening
of the detent ring can be effected, for example, by way of a pair of beveled
surfaces on the
detent ring and the aforementioned actuating part.
The actuating part for unlocking or, if applicable, for locking the coupling
of the drive train may
be configured in a variety of ways. Advantageously, the actuating part is
configured for
automatic operation so that it operates automatically when the attachment is
being pulled off or
plugged on, unlocking or locking the engagement part of the drive train
coupling automatically.
In a particularly advantageous further aspect of the invention, the actuating
part may be
connected to a coupling insert, in particular being integrally made of one
piece therewith, which
coupling insert is arranged in the tubular coupling member of the attachment
and serves to be
locked with the neck of the toothbrush handpiece by positive and/or frictional
engagement in
order to hold the attachment on the toothbrush handpiece. Advantageously, this
coupling insert
of the attachment is axially displaceable relative to its coupling member in
the attachment
longitudinal direction and connected to an engagement part which is lockable
with the neck of
the toothbrush handpiece by positive or frictional engagement, such that the
coupling insert
experiences an axial movement in the attachment longitudinal direction
relative to the tubular
coupling member of the attachment when the attachment is pulled off and/or
plugged onto the
toothbrush handpiece. When the attachment is pulled off or plugged on, this
configuration
produces automatically also an axial actuating movement of the actuating part
for the drive
shaft coupling which is converted into the actuating movement of the
engagement part of the
drive train coupling in a direction transverse to the attachment longitudinal
axis.
In this arrangement, the actuating part may be configured in particular in the
form of a pulling
hook which protrudes from the frontal end of the preferably sleeve-shaped
coupling insert and
extends as far as the drive train coupling for engagement there with the
engagement part of the
coupling contour of the plug-on shaft.
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Advantageously, the attachment may be configured with regard to said coupling
insert in such a
way that the axial movement of the coupling insert relative to the coupling
member and/or an
actuating part provided thereon produces an unlocking and/or locking movement
of the
engagement section of the coupling insert in a direction transverse to the
attachment
longitudinal direction. If the coupling insert or its engagement section is
locked onto the
toothbrush handpiece, it is first necessary for the attachment or an actuating
part connected
thereto to be moved axially substantially in the attachment longitudinal
direction relative to the
locked coupling insert, whereby the coupling insert initially does not move
relative to the
toothbrush handpiece on account of its being locked thereto. Not until the
axial relative
movement has released the lock is it possible for the coupling insert to be
pulled together with
the attachment off the toothbrush handpiece. This two-stage attaching or
connecting
mechanism permits even non-self-locking connecting or faying contours to be
provided at the
interface between the toothbrush handpiece and the coupling insert because
fixedly securing is
assured nevertheless by the locking movement which takes place in a direction
transverse to
the attachment longitudinal direction.
As an alternative to the fastening of the actuating part of the drive train
coupling to such a
coupling sleeve it would also be possible generally for the actuating part to
be configured as a
part separate from the connecting means of the tubular coupling member on the
handpiece
neck. For example, the actuating part could be in the form of a slide mounted
for displacement
on the coupling member, said slide preferably including a fingertip control
and/or being
displaceable, for example, by a user's thumb in the attachment longitudinal
direction relative to
the tubular coupling member in order to release or lock the drive train
coupling.
The coupling contour of the drive train coupling may be generally shaped in a
variety of ways.
Notably the coupling contour of the plug-on shaft may define a conical mount
which widens in a
direction away from the working head of the attachment, has a bevel of more
than 7 and is
accordingly no longer configured to be self-locking, while in corresponding
manner the stub-
shaped connecting member of the drive shaft of the toothbrush handpiece, which
conventionally projects at the front end, may be conically shaped in
corresponding manner with
a bevel of more than 7 . In reversal of the kinematics, so to speak, it is
generally also possible
to reverse this arrangement and provide on the drive shaft of the handpiece a
conical mount
preferably of the aforementioned type, into which the advantageously equally
conical plug-on
shaft of the attachment can be plugged. Preferred however is the previously
described
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arrangement with the mount in the plug-on shaft. Said relatively pronounced
taper of the con-
necting members of the two shafts renders the connection insensitive to
tolerances because
any difference in diameter can be compensated for by a corresponding axial
movement.
Such a conical configuration of the interface faying surfaces of the drive
train coupling is
advantageous particularly in connection with the previously described locking
of the two shaft
parts by means of an engagement part movable in a direction transverse to the
attachment
longitudinal direction, because such a locking prevents an unwanted
disengagement of the
relatively cooperating coupling contours even in the presence of a non-self-
locking
configuration. Nevertheless, the pair of conical faying surfaces enables a
firm and zero-play
shaft connection to be accomplished which is lenient to tolerances.
Alternatively or in addition, said conical configuration of the faying
surfaces of the drive train
interface may also be used to advantage with a locking of the tubular coupling
member of the
attachment brush on the neck of the toothbrush handpiece. By locking the
tubular coupling
member onto the toothbrush handpiece by positive and/or frictional engagement,
also the
coupling contours of the plug-on shaft and the drive shaft are securely held
against each other
without an unintentional disengagement being possible. In particular it is an
advantage in this
case if the coupling contours of the two shaft parts are biased into their
coupling position, which
can be accomplished, for example, by guiding the drive shaft axially
displaceably in the
toothbrush handpiece and biasing it toward the attachment brush by means of a
suitable spring
device. Alternatively or in addition, it is also possible for the plug-on
shaft in the attachment
brush or at least for the end piece carrying the coupling contour to be biased
by a suitable
spring away from the working head of the attachment brush, i.e., toward the
toothbrush
handpiece. To this effect, for example, the plug-on shaft may include two
shaft parts slidable
one into the other and out of each other in the manner of a telescopic shaft.
The coupling contours on the plug-on shaft and/or the drive shaft can be
implemented in a way
affording particular ease of manufacture by the absence of any undercuts and
axially effective
snap-action connections on the coupling contour of the plug-on shaft and the
complementary
coupling contour of the drive shaft. Accordingly, the two shaft parts are
simply plugged one into
the other, with the torque transmission being made possible by the conical
faying surface which
is in particular not symmetrical about the axis. In this arrangement, the
axial securing of the
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coupling contours one upon the other is ensured by the previously described
locking of the
tubular coupling member of the attachment onto the neck of the toothbrush
handpiece.
In another preferred aspect of the invention, as an alternative or in addition
to the previously
described features of the attachment, the plug-on shaft of the attachment is
configured in
respect of its coupling section in such a way that it can be coupled with
different toothbrush
handpieces, more accurately speaking, with different drive shafts of such
toothbrush
handpieces.
Notably the plug-on shaft of the attachment may include two separate,
independently effective
coupling contours, each for positive-engagement coupling to different drive
shafts of different
toothbrush handpieces. In this context, separate and independently effective
means
advantageously that a drive shaft of the toothbrush handpiece to be coupled to
the plug-on
shaft is moved into force- or torque-transmitting engagement with only a
respective one of the
two coupling contours. In a further aspect of the invention, a first one of
the two coupling
contours has an engagement part movable in a direction transverse to the
attachment
longitudinal direction for locking, by positive and/or frictional engagement,
with the drive shaft of
the toothbrush handpiece, while a second one of the two coupling contours
includes a conical
faying surface for engagement with an equally conical faying surface on the
drive shaft of the
toothbrush handpiece, which is devoid of undercuts and devoid of axially
effective snap-action
connections. In particular the first one of the two coupling contours may be
configured in the
previously described manner and include as transversely movable engagement
part, for
example, a detent finger, a split detent ring or a pivotal part which is
actuatable by way of the
axially movable actuating part particularly in the form of a pulling hook
secured to the
aforedescribed coupling sleeve. The second one of the two coupling contours
may be
advantageously non-self-locking in the manner previously described and it may
have a taper
with a bevel of more than 7 .
The present invention will be explained in more detail in the following with
reference to
preferred embodiments and associated drawings. In the drawings,
FIG. 1 is a fragmentary view, in longitudinal section, of an electric
toothbrush according to a
preferred embodiment of the invention, showing the front-end connecting member
of the
toothbrush handpiece and the attachment brush seated thereon, with the
coupling
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insert, which is seated in the tubular coupling member of the attachment
brush, being
shown in its locked position;
FIG. 2 is a longitudinal sectional view of the toothbrush of FIG. 1, which is
turned through 900
compared to the illustration in FIG. 1;
FIG. 3 is a cross-sectional view of the toothbrush of FIGS. 1 and 2 in the
region of the catch
mechanism between the coupling insert in the attachment brush and the neck of
the
toothbrush handpiece;
FIG. 4 is a simplified and enlarged fragmentary view, in longitudinal section,
of the electric
toothbrush of FIGS. 1 to 3, showing the connection of the plug-on shaft of the
attachment brush with the drive shaft of the handpiece of the toothbrush in
more detail;
FIG. 5 is a fragmentary view, in section, of the drive train coupling in the
coupling member of an
attachment brush according to another preferred embodiment of the invention,
in which
the coupling has a pivotally mounted locking arm with a cam-type actuating
part;
FIG. 6 is a fragmentary view, in section, of the drive train coupling in the
coupling member of an
attachiment brush according to another preferred embodiment of the invention,
in which
the coupling has a pivotally mounted locking arm which is mounted for pivotal
movement
on a spring part on a side opposite the pulling hook of the actuating part;
FIG. 7 is a fragmentary view, in section, of the drive train coupling in the
coupling member of an
attachrnent brush according to another preferred embodiment of the invention,
in which
the coupling has a pivotally mounted locking arm, with the pulling hook of the
actuating
part being arranged to act on a side opposite the detent projection of the
locking arm;
FIG 8 is a fragmentary view, in section, of the drive train coupling in the
coupling member of an
attachment brush according to another preferred embodiment of the invention,
in which
the coupling includes a split extensible detent ring;
FIG. 9 is a fragmentary view, in longitudinal section, of an electric
toothbrush according to
another preferred embodiment of the invention in which solely the coupling
insert in the
coupling member of the attachment brush is locked with the toothbrush
handpiece, while
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the drive train coupling is comprised of conical faying surfaces of the non-
self-locking
type without axial locking;
FIG. 10 is a fragmentary view, in longitudinal section, of the toothbrush of
FIG. 9 in a plane
turned through 900 compared to FIG. 9; and
FIG. 11 is a cross-sectional view of the connection between the attachment
brush and the
handpiece of the toothbrush of FIGS. 9 and 10 in the region of the detent
hooks of the
couplirig insert.
The toothbrush 1 shown in FIGS. 1 to 3 comprises a handpiece 4 and, connected
thereto, an
attachment in the form of an attachment brush 33. The handpiece 4 comprises in
a manner
known in the art a housing in which a drive motor and a power supply device,
for example in the
form of a rechargeable battery, are accommodated and on which an actuating
switch for
switching the drive on and off is provided. On the frontal end of the
handpiece 4 shown in FIG.
1 the housing of the handpiece 4 forms a forward-protruding stub-shaped
connecting member
34 which in the embodiment shown is conically shaped and tapers towards its
free end, with the
conical contour of the connecting member 34 advantageously having a bevel 35
of more than
7 and therefore cannot be clamped in self-locking manner. Extending from the
frontal end of
said connectirig member 34 is a drive shaft 31 which is adapted to be driven
in an oscillatory
rotational motion.
The attachment brush 33 comprises a working head 2 with a set of bristles, not
shown in
greater detail, which in the embodiment shown is adapted to be driven in an
oscillatory
rotational motion about a bristle zone axis pointing approximately in the
bristle longitudinal
direction. Said working head 2 is carried by an on the whole tubular coupling
member 3 which
can be plugged onto the neck or the connecting member 34 of the toothbrush
handpiece 4. In
the interior of said tubular coupling member 3 the attachment brush 33
comprises a plug-on
shaft 29 adapted to be coupled to the drive shaft 31 of the handpiece in a
manner preventing
relative rotation, as will be described in more detail in the following.
To fasten the attachment brush 33 to the handpiece 4 the tubular coupling
member 3 includes a
coupling insert 5 in the form of a coupling sleeve which is accommodated in
the tubular
coupling member 3 for axial displacement in the direction of the attachment
longitudinal
direction 38. The coupling member 3 forms with its inner wall an insert mount
16 in which the
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coupling insert 5 is seated with a snug fit at least in its locked condition,
which will be described
below in more detail. It will be understood that the insert mount 16 may be
configured in a
variety of ways, for example, it may be of an on the whole cylindrical or on
the whole tapered or
conical configuration, or also it may include a cylindrical section as well as
a conical section. In
the embodiment shown, the insert mount 16 is on the whole slightly conical,
with a cylindrical
section being provided on its region 40 intended for the inner end of the
coupling insert 5.
A spring, not shown in the Figure for clarity of illustration, advantageously
holds the coupling
insert 5 axially in the coupling member 3 or biases it into a predetermined
initial position. Said
spring may be provided advantageously on the side of the coupling insert 5
close to the working
head 2 and be connected to said coupling insert 5 on the one hand and be fixed
to the coupling
member 3 on the other hand.
The sleeve-shaped coupling insert 5 forms with its inner circumferential
surface a mount 13
which is shaped to conform to the outer circumferential contour of the
connecting member 34 of
the toothbrush handpiece 4 so that said handpiece can be inserted into the
mount 13 with a
snug fit. The mount 13 is of an on the whole conical configuration, with the
bevel of the
respective taper - adapted to the connecting member 34 - being greater than 7
. The coupling
insert 5 has two mutually opposing engagement sections 6 in the form of
resilient coupling or
spring fingers 12 which are integrally made of one piece with the remaining
body of the coupling
insert 5 and are separated from said insert by U-shaped slits so that
engagement fingers 12
can spring open and shut radially in a direction transverse to the attachment
longitudinal
direction 38. The engagement fingers 12 extend with their longitudinal axis
substantially
parallel to the attachment longitudinal direction 38.
As FIG. I shows, the engagement fingers 12 carry on their free ends radially
inwardly
protruding detent hooks 11 adapted to snap into conformably shaped detent
notches 41 in the
outer circumferential surface of the connecting member 34 of the toothbrush
handpiece 4. It
will be understood, of course, that other suitable detent contours may be
provided, for
example, a geometrical reversal of the illustrated embodiment comprising
detent projections on
the connecting member 34 and detent notches on the engagement fingers 12.
As FIG. 3 shows, the connecting member 34 and the mount 13 defined by the
coupling insert 5
are not circular in cross section but are both flattened. In particular the
connecting member 34
has two mutually opposing flattened surfaces where the detent notches 41 are
provided. The
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engagement fingers 12 have their inner sides complementary to the two
flattened surfaces and
the detent notches 41 provided therein.
To be able to release the lock shown in FIG. 1 between the coupling insert 5
and the
connecting member 34 of the toothbrush handpiece 4, the coupling member 3 of
the
attachment brush 33 includes an actuating member 7 in the form of a ring which
in the
illustrated embodiment is seated on the frontal end of the tubular coupling
member 3 on the
side remote from the working head 2. The ring may be provided advantageously
as a colored
ring so that it performs the dual function of individualizing the attachment
brush 33 by the user
being able to identify "his" or "her" attachment brush from the color of the
actuating member 7.
The actuating member 7 comprises two unlocking sections 8, each in the form of
an actuating
finger 21 projecting axially in the attachment longitudinal direction into the
interior of the
coupling merriber 3. These actuating fingers 21 engage advantageously in the
mount 13
formed by the coupling insert 5 in the area of the free ends of the engagement
fingers 12,
Provided on the projecting ends of the actuating fingers 21 are beveled
surfaces 10 which
serve to cooperate with beveled surfaces on the projecting ends of the
engagement fingers 12
of the coupling insert 5. The beveled surfaces 9 and 10 are formed such that
during the axial
riding motion of the engagement fingers 12 over the actuating fingers 21, the
engagement
fingers 12 are spread radially outwardly, whereby they are lifted out of the
detent notches 41 in
the connecting member 34 of the toothbrush handpiece 4.
In the illustrated embodiment the coupling insert 5 is axially displaceable in
the coupling
member 3 in order to produce the axial movement. Alternatively or in addition,
the annular
actuating member 7 could be axially displaceable in the coupling member 3. In
the preferred,
illustrated embodiment the actuating member 7 is however securely seated on
the coupling
member 3 by a catch mechanism 42 on the inner wall of the coupling member 3.
As shown in FIG. 2 in particular, also the coupling interface between the plug-
on shaft 29 and
the drive shaft 31 is lockable by positive engagement by an engagement part
movable in a
direction transverse to the attachment longitudinal direction 38. In the
embodiment shown, said
engagement part 106 is formed by an engagement finger 112 pivotal about a
transverse axis
140 and having on its inner circumferential surface a detent projection in the
form of a detent
hook 111 which protrudes towards the inside of the mount 43 intended for the
drive shaft 31. In
the embodiment shown, said engagement finger 112 is advantageously integrally
made of one
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piece with the body of the plug-on shaft 29. The pivot axle or transverse axle
140 may be
formed by weakening the material at selected regions, cf. FIG. 2. In the
embodiment shown,
the detent hook 111 is advantageously provided in the form of a beveled
projection fitting
snugly in an approximately V-shaped notch 131 extending in the drive shaft 31
in a transverse
direction, cf. IFIG. 2.
To actuate said engagement finger 112, an actuating part 107 in the form of a
pulling hook 132
is provided, vvhich is integrally made of one piece with the previously
described sleeve-shaped
coupling insert 5 and projects from its frontal surface as far as the area of
the drive shaft
interface. The pulling hook 132 embraces the end of the engagement finger 112
on the side
remote from the transverse axle 140, and a pair of beveled surfaces 109 and
110 is provided at
the overlapping ends of the engagement finger 112 and the pulling hook 132 so
that, while the
engagement finger 112 rides over the pulling hook 132 or vice versa, the axial
relative
movement between the two parts is converted into a radial actuating movement
of the
engagement finger 112.
As the enlarged fragment of FIG. 4 shows, the blind-hole-shaped mount 43 in
the plug-on shaft
29 includes two independently active coupling contours 130a and 130b. The
first one 130a of
the two coupling contours is formed by the engagement finger 112 described and
an
associated plug-in contour of the mount 43 which generally may have a
cylindrical section 130c.
In the embodiment shown, a complementary drive shaft 31 is plugged in whose
engagement
section is of an overall cylindrical configuration and whose cross-section is
conveniently not
circular cylindrical but has a flattened surface on one side in order to
ensure a corresponding
torque transmission. In this arrangement, the drive shaft 31 is secured to the
plug-on shaft 29
by means of the transversely movable engagement finger. The second one 130b of
the two
coupling contours is axially spaced from the first coupling contour 130a and
in the embodiment
shown is arranged in advance of said first coupling contour 130a as seen
looking from the end
of the plug-on shaft 29. In the embodiment shown, it is comprised of an
overall conical section
of the mount 43 which in the embodiment shown has a plane beveled surface 130d
inclined
relative to the longitudinal axis of the plug-on shaft 29, advantageously at a
bevel of more than
7 . As shown in particular in FIG. 4 in more detail, the conical second
coupling contour
advantageouslly extends as far as into the region of the detent hook 111 so
that the second
coupling contour may also be utilized in cooperation with the detent hook 111
of the
engagement finger 112. In the embodiment shown in FIGS. 2 and 4, however, said
second
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coupling contour 130b is not utilized because the drive shaft 31 of the
toothbrush handpiece 4
is cylindrically shaped in the described manner.
Consequently, the following mode of operation results:
While the attachment brush 33 is being plugged onto the toothbrush handpiece
4, the
connecting member 34 threads into the mount 13 of the coupling insert 5,
whereby the detent
hooks 11 slicie along the outer circumferential surface of the connecting
member 34 as the
engagement fingers 12 spread open. Upon the fully plugged-on position being
reached, the
engagement fingers 12 spring radially inwardly causing the detent hooks 11 to
engage the
detent notches 41 with a snap action. The coupling insert 5 forms a spring
catch which upon
being plugged onto the toothbrush handpiece 4 locks automatically to said
handpiece. In the
locked position the connecting member 34 sits in the conical mount 13 with a
snug fit. Similarly,
the coupling insert 5 is snugly received in the insert mount 16 of the
coupling member 3.
To release the positive-engagement lock the user simply needs to pull the
attachment brush 33
in the attachnnent longitudinal direction 38 off the toothbrush handpiece 4.
This results first in
an axial relative movement between the coupling member 3 and the coupling
insert 5 because
the latter is held by the detent hooks 11 axially securely on the toothbrush
handpiece 4. As the
result of such axial relative movement the actuating fingers 21 of the
actuating member 7 move
under the engiagement fingers 12 or the detent hooks 11 so that the engagement
fingers 12 are
lifted by way of the pair of beveled surfaces 9 and 10 radially out of the
detent notches 41.
During the axial relative movement between the coupling insert 5 and the
coupling member 3, a
corresponding deformation of the spring sections 18 and 19 of the spring 17
occurs.
When the enqagement fingers 12 with their detent hooks 11 are unlocked from
the toothbrush
handpiece 4, the coupling insert 5 is pulled together with the coupling member
3 off the
handpiece 4. The spring 17 operates to return the coupling insert 5 to its
initial position. This
spring return function is advantageous but not absolutely necessary. Due to
the conical
configuration of the mount 13 and/or a possibly provided follower element, the
coupling insert 5
would be pushed back into its locking position when plugged again onto the
toothbrush
handpiece 4 even in the absence of the spring 17.
At the same time, the axial movement of the coupling insert 5 or of the
pulling hook 132 formed
thereon causes the lock between the plug-on shaft 29 and the drive shaft 31 to
be released. By
CA 02670768 2009-05-27
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way of the pair of beveled surfaces 109 and 110, the axial movement of the
pulling hook 132
relative to the engagement finger 112 pulls the latter radially outwardly,
causing it to be
unseated from the notch 131 in the drive shaft 31. The drive shaft 31 can thus
be pulled off the
plug-on shaft 29.
An alternative possibility of embodying the drive shaft interface and its
locking engagement is
shown in FIG. 5. Here too the engagement part of the plug-on shaft 29 which
effects the
locking engagement is provided in the form of a pivotal engagement finger 112
having an
inwardly protruding detent hook 111, said engagement finger 112 forming, so to
speak, a
pivotal latch or a pawl. In this arrangement, the engagement finger 112 is
formed as a part
separate from the remaining body of the plug-on shaft 29 and arranged in an
axially extending
recess 106 in the area of the mount 43, so that the detent hook 111 projects
inwardly into the
mount 43, cf. FIG. 5. The transversely extending pivot axle 140 may be formed
by an axle pin,
for example.
In the embodiment shown in FIG. 5, the engagement finger 112 is actuated by a
function arm
135 protruding axially from the coupling insert 5 and forming the actuating
part 107. In
particular, for actuating the pivotal engagement finger 112 cam-type beveled
surfaces 109 and
110 are provided at the front end of the function arm 135 and the engagement
finger 112, with
the beveled surface 109 on the engagement finger 112 having a lever arm in
relation to the
finger's pivot axle 140 and in the embodiment shown is arranged between said
pivot axle 140
and the detent hook 111, cf. FIG. 5.
The mode of operation resulting from this arrangement corresponds essentially
to the
previously described embodiment of FIGS. 1 to 4.
Another variant of the engagement part 106 is shown in FIG. 6, according to
which the
engagement part 106 is formed by a pivotal pawl 136 which extends transversely
across and
beyond the mount 43 in the plug-on shaft 29. Similar to the previously
described embodiments,
the detent pawl 136 also has a detent hook 111 for engagement in the notch 131
of the drive
shaft 31. In the embodiment of FIG. 6, however, the detent pawl 136 is mounted
on the plug-on
shaft 29 on the opposite side of the detent hook 111 about a pivot axle 140
which equally
extends in a transverse direction, cf. FIG. 6. A spring device 137 biases the
detent pawl 136
into its locking position, and in the embodiment shown said spring device 137
may be formed
by a spring arm integrally formed on the plug-on shaft 29.
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To actuate the detent pawl 136 an actuating part 107 in the form of a pulling
hook 132 is
provided which protrudes from the coupling insert 5 axially as far as the area
of the drive shaft
interface. Similar to the embodiment of FIGS. 1 to 4, actuation of the detent
pawl 136 is
effected by way of a pair of beveled surfaces 109 and 110.
FIG. 7 shows an embodiment of the locking mechanism between the two shafts 29
and 31
similar to FIG. 6. Here too the detent pawl 136 extends transversely across
and beyond the
mount 43 in the plug-on shaft 29, but in contrast to the embodiment of FIG. 6
the transversely
extending pivot axle 140 and the detent hook 111 are arranged on the same side
of the drive
shaft 31. The section 136a of the detent pawl 136 extending to the opposite
side of the mount
43 forms an actuating arm which is actuatable by the pulling hook 132 by way
of a pair of
beveled surfaces 109 110 similar to the previously described embodiment.
Another embodiment of the locking mechanism between the plug-on shaft 9 and
the drive shaft
31 is shown in FIG. 8. According to this embodiment, the plug-on shaft 29
includes an
engagement part 106 in the form of a detent ring 125 which can be radially
widened and
narrowed, which can be of a longitudinally slotted configuration, for example,
to enable its
widening. Advantageously, the detent ring 125 is configured such as to be
elastically biased
into its locking, narrowed position. As FIG. 8 shows, the detent ring 125 has
on its inner
circumferential surface an inwardly protruding detent contour in the form of a
detent hook 111
which engages in a notch 131 in the drive shaft 31.
In this arrangement, the detent ring 125 is seated in a circumferential recess
on the body of the
plug-on shaft 29. In the region of said detent hook 111 the detent ring 125
has on its outer
circumferential surface an engagement notch which cooperates with the pulling
hook 132 which
in turn is integrally formed on the coupling insert 5 in axially protruding
manner. Again, a pair of
beveled surfaces 109 and 110 may be provided on the detent ring 125 and the
pulling hook
132. Performing a supporting function, an expansion chamfer may be provided on
the recess
in the outer circumferential surface of the plug-on shaft 29 and/or on the
abutting front edge of
the detent ring 125, so that an axial movement of the detent ring 125 relative
to the body of the
plug-on shaft 29 by means of the pulling hook 132 produces an expanding
movement.
The mode of operation of the locking engagement of the drive shaft interface
is similar to the
previously described embodiments.
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FIGS. 9 to 11 show an advantageous embodiment of the invention which is
generally similar to
the embodiment of FIGS. 1 to 3. The same reference characters are applied to
similar parts as
those disclosed in the embodiment of FIGS. 1 to 3. A significant difference
lies in the
construction of the coupling interface in the drive train. As is shown in
particular in FIG. 10, in
the illustrated embodiment the plug-on shaft 29 of the attachment brush 33 is
coupled to the
drive shaft 31 of the handpiece soleiy by conical faying surfaces, the drive
shaft 31 being
conically shaped on its end protruding from the housing of the handpiece 4,
and a bevel being
equally allowed to be greater than 7 . The plug-on shaft 29 has a conformably
shaped, frontally
open, advantageously blind-hole type mount 43 which comprises a faying surface
130c which is
adapted to the taper of the drive shaft 31 and likewise has a bevel of more
than 7 . By firmly
plugging on the attachment brush 33, a connection by positive and/or
frictional engagement can
be established between the plug-on shaft 29 and the drive shaft 31. This
connection between
the shafts may be free of axially effective snap-action connections or other
axial holding means.
To make sure that only one of the two coupling contours 130a and 130b of the
plug-on shaft 29
is used, for example, to ensure that a user can only use "his" or "her"
attachment brush or
toothbrush, it is possible for one of the two coupling contours 130a and 130b
to be covered by
non-releasable insertion of an adapter, rendering it dead, so to speak. For
example, an adapter
could be non-releasably inserted into the mount 43 of the plug-on shaft 29,
which adapter
closes the first coupling contour 130a so that only the conical second
coupling contour 130b is
left for use. Alternatively or in addition, such an adapter could also be
provided on the
handpiece, in particular by plugging it onto the drive shaft 31 of the
toothbrush handpiece 4.
For example, a conical adapter could be slipped onto the drive shaft 31 shown
in FIG. 4 by way
of example and be non-releasably snapped into the notch 131 there, so as to
enable a coupling
to be effected with the conical second coupling contour 130b.
