Note: Descriptions are shown in the official language in which they were submitted.
1330383
IMPROVEMENTS IN ELECTRIC TOOTHBRUSHES
BACKGROUND OF THE INVENTION
The invention relates to an electric toothbrush
with a handle which is to be manually guided and
comprises a motor and gearing, and with a brush
member which has a brush head with several cylindrical
bristle holders rotating separately next to one another.
Such a toothbrush is disclosed, for example, in
US-PS-4156620.
In this known toothbrush, the brush member is not
movable. The teeth are cleaned exclusively by the
rotating movement of the bristle holders.
In the toothbrush known from US-PS 4156620 there is a
connecting rod which is constructed as a toothed rack in
the region of the brush head. The br~stle holders each
carry a gearwheel inside the brush head, all gearwheels
in a row of bristle holders intermeshing and each second
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gearwheel in a row engaging in teeth ln the toothed
rack. Therefore, the ad~acent br~istle holders rotate in
20 opposite directions when the aonnecting rod moves to and ` ~
fro~ and this is advantageous for cleaning teeth. ~ `
The known toothbrush is relatively complicated~in
construction owing to the plurallty of gearwheels~ and~
the connecting rod constructed as a toothed rack. To
prevent the gearwheels from jamming, the toothbrush must
be produced with very close production tolerances. ~This
entails high production costs and is accompanied by the
risk of even slight inaacuracies in production leading
to an interruption in operation.
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SUMMARY OF THE INVENTION
~he object of the invention is to improve a toothbrush
of the type mentioned at the outset such khat it can
clean the teeth more vigorously and, at the same time,
is able to massage the gums.
According to the invention, this ob;ect is achieved by
providing an electric toothbrush having a handle, which
is adapted to be manually guided and comprises a motor
and gearing, and a brush member which has a brush head
with a plurality of cylindrical bristle holders rotating
separately next to one another, said gearing being
constructed and arranged to set the brush holder into
both an oscillating and a reciprocating movement.
Toothbrushes whose bristle members perform both an
oscillating and a reciprocating movement are known, Eor
example Erom FR-PS 1525112. However, the invention
consists ln transferring this principle oE a rocking
bristle member to a toothbrush with rotating tufts o~
bristles. This allows particularly eEective cleaning
o the teeth and, in addition, very good massage oE the
gums,
Another object of the invention is to provide a
toothbrush of the type mentioned at the outse~ which is
constructed such that the individual bristle holders can
be driven by the simplest means so that the toothbrush
can be produced economically and can operate
particularly reliably. In order to~achieve this ob~ect,
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a connecting rod is provided which has, inside the brush
head, grooves running transversely to its main
extension, into which the brlstle holders each engage
with a cam running parallel to their axis of rotation~
With such a toothbrush, gearwheels are not required for
producing the rotating movement of the bristle holders.
The rotatlng movement of the bristle holders is produced
simply in that the connecting rod shif-ts the cam due to
its reciprocating movement. The drive is therefore very
simple in design and does not require close production
tolerances The term "transversely to the main
extension" does not mean that the grooves have to run
perpendicularly to the main extension; a course directed
obliquely to it is suificient. Instead of grooves,
obliquely running projections are equivalent solutions.
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The connecting rod must have inclined planes for ` ;
rotating the cams.
In a particularly advantageous embodiment of the
invention, the brush head has two adjacent rows of
bristle holders and, in the central position of the
connecting rod, the cams of the bristle holders in the
two rows are orientated such that they face one another
in the transverse direction to the brush member. As the~
cams face one another, the connecting rod can be narrow
in construction in the region of the brush head, and the
respective adjacent bristle holder in a row rotates in
the opposite direction. If the cam were arranged
alternately to the centre of the brush head and to the
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exterior of the brush head, then all bristle holders
would rotate in the same direction. The invention
therefore allows the direction of rotation of the
bristle holders to be altered in a simple manner.
With electric toothbrushes which are constructed like a
manual toothbrush with respect to the brush head, it has
proved advantag~ous if the brush head makes a circling
movement. This circling movement is produced by a
speclal gear which pushes a toothbrush shaft to and fro
and also allows it to oscillate about its longitudinal
axis. Reference is made to US-PS 3160902 as an example
of such a state of the art. This known principle of the
oscillation of the toothbrush head can easily be
transferred to the toothbrush according to the invention
if the connecting rod is arranged non-rotatably in the
brush member and the brush member is arranged on the
handle so as to rotate about its longitudinal axis and
if the gearing is designed to rotate the connecting rod
alternately about its longitudinal axis in addition to
shifting the connecting rod in the longitudinal
dlrection.
The brush member can be produced inexpensively and can
easily be exchanged i, according to a further
embodiment of the invention, the brush member i~
detachably ! connected to the handle and the connecting
rod has a snap connectlon at~its handle end for
connection to the shaft of the toothbrush.
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Instead of allowing the entire brush member to oscillate
about its longitudinal axis, the individual bristle
holders can also travel alternately more or less far
from the brush member if, according to a further
S embodiment of the invention, the connecting rod is
rotatable about its longitudlnal axis in the brush
member and the brush member on the handle is arranged
non-rotatably about its longitudinal axis and if the
bristle holders are arranged axlally movably with
respect to their axis of rotation in the brush head~
Particularly simple gearing for producing the rotating
movement and oscillating movement is distinguished in
that it comprises a bevel wheel which is driven by a
bevel pinion of the motor, revolves about a pivot pin
running transversely to the connecting rod and, with an
eccentric peg orientated parallel to its pivot pin,
engages in a recess in a rocker fixed on a toothbrush
shaft which is axially movably and rotatably arranged in
the handle and is orientated in the longitudinal
direction o the handle part.
The gearing operates quite particularly wlth low
friction and can be produced very inexpensively i,
according to a further embodiment of the in~ention, a
sliding block inserted in a recess in the rocker is
arranged rotatably on the eccentric peg and if the two
lateral faces of the sliding block running parallel to
the axis of the toothbrush shaft and/or the
corresponding lateral faces of the recess ~are bent or
bevelled to allow a rocking motion of th~ rocker.
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The rocking motion of the rocker is produced
particularly simply if, according to a further
embodiment of the invention, the part oF -the rocker
coMprising the recess for the sliding block is at a
radial distance from the toothbrush shaft. Wlth this
embodiment, the sliding block acts at a considerable
distance ~rom the pivot axis of the rocker which is at
the same time the axis of the toothbrush, on the rocker.
A relatively great rocking moment is thus produced so
that the oscillating movement of the brush member takes
place with sufficiently great force. ~ ;
An embodiment in which the eccentric peg engages from
the side of the toothbrush into the sliding block is
very compact.
The invention allows numerous embodiments. One
embodiment is shown in the drawings and is described
below for further clariflcation of its basic principle.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 shows a schematic longitudinal section through
a toothbrush according to the invention;
Figure 2 shows a perspective exploded view of a brush
member of the toothbrush shown in Figure 1;
Figure 3 shows a longitudinal section through the fronk
region of the brush member;
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Figure 4 shows a plan view of the front region of the
brush member; ;~
Figure 5 shows a longitudinal section through the
gearing of the toothbrush. `~ -
Figure 6 shows a plan view of a rocker of the gearing
with adjacent components; and
Figure 7 shows a cross sec-tion through the toothbrush
along the line VII-VII in Figure 5.
DESCRIPTION OF PREFERRED EMBODIMEN'r . ~ ~ :
The toothbrush shown as a whole in Figure 1 consists of
a handle 1 and a brush member 2 fixed detachably and
rotatably thereon~ In the handle 1 there is arranged a
motor 3 which drives a toothbrush shaft 5 via gearing 4
such that the toothbrush shaft 5 simult~neously per~orms
15 an oscillating movement about its longitudinal axis and ;
an axial shifting movement. The gearing 4 has a bevel
pinion 6 which is driven by the motor 3 and drives a
bevel wheel 7 which is rotata~le about a pivot pin 8
arranged transversely to the motor 3. Parallel to its
pivot pin 8, this bevel wheel 7 has an eccentric peg 9
on wl1ic}1 there rests in rotatable manner a sliding block
10 arranged non-rotatably inside a rocker 11. Owing to
the circular path of movement of the eccentric peg 9,
the rocker 11 is moved forwards and backwards. It
cannot move to the side as the r~ocker 11 i~ rlgidly
connected to the toothbrush shaft 5 and the toothbrush
shaft 5 is held axlally movably and rotatably ln the
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handle 1. This guidance of the toothbrush shaft 5
causes the rocker 11 with the toothbrush shaft 5 to rock
about the longitudinal axis of the toothbrush shaft 5
when the eccentric peg moves from the plane of the
drawlng~ as illustrated in more detail below.
connecting rod 12 is arranged axlally movably but non-
rotatably relative to the brush member 2 in the brush
member 2. This connecting rod 12 has, at its handle
end, a snap connection 13 with which it is locked to the
toothbrush shaft 5 non-rotatably relative to the
toothbrush shaft 5. The brush member 2 is accordlngly
detachably connected to the handle with a catch
connection 14. However, this catch connection 14 is
constructed such that the brush member 2 can rotate
about its longitudinal axis relative to the handle 1,
this being necessary as the toothbrush shaft S and
there~ore also the connecting rod 12 can rotate to a
limited extent about the longitudinal axis o~ the
toothbrush.
The brush member 2 has, at its front end, a brush head
15 into which there are rotatably inserted several
cylindrical bristle holders 16 to 20 which pro~ect with
tufts 21 o~ bristles ~rom the brush head 15. Inside the
brush head, the bristle holders 16 to 20 each have a cam
22 which engages in a transversely running groove 23 of
the connecting rod 12. When the connecting rod 12 moves
to and fro, the cams 23 are shifted and the bristle
holders 16 to 20 thus rotated.
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Figure 2 clarifies the design of the brush member 2. It
can be seen that the connecting rod 12 has, at its brush
head end, a total of five successive, transversely
running grooves 23, 23a, 23b, 23c and 23d, into which
the cams 22 of the bristle holders 16 to 20 can engage.
In this embodiment, the brush head 15 is constructed
such that, parallel to the row of bristle holders 16 to
20, it has a further row of bristle holders of which the
bristle holder 16b is shown. The bristle holder 16b and
the other bristle holders in its row also engage with a
respective cam 22b into these grooves 23, 23a, 23b, 23c,
23d of the connecting rod 12. As shown in Figure 2, all
bristle holders 16 to 20 and 16b are rotatably arranged
in a lid 24 which can be inserted from above a~ an
insert into the brush head 15
The sectional view according to Figure 3 shows how the
bristle holders 16 to 20 with their respective cams 22
engage in the respective grooves 23, 23a, 23b, 23c, 23d
in the connecting rod 12. Figure 4 shows that, in tha
central position o the connecting rod 12, the cams 22,
22b and, accordingly, the other cams face one another in
th~ transverse direction of the brush head 15.
Figure 5 shows, on a larger scale than Figure 1, how the
motor 3 with its bevel pinion 6 drives the bevel wheel
7. The pivot pin 8 of this bevel wheel 7 is mounted at
both ends in the housing o~ the handle 1. It~can be
seen that the rocker 11 has a recess 25 in which the
sliding block 10 rests. The eccentric peg 9 engages
rotatably in this sliding block 10O The rocker 11 is
connected non~rotatably and non movably to ~he
toothbrush shaft 5.
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Figure 6 shows that the recess 25 in the rocker 11
rotationally engaged on the toothbrush shaft 4 is
rectangular in cross section and the sliding block 10
also rectangular accordingly. Thls sliding block 10 has
a bore 26 into which the eccentric peg 9 engages. If
the eccentric peg 9 rotates about 180 and khus assumes
its lower position shown in dot dash lines, then the
rocker 11 is moved downwards accordingly so that the
toothbrush shaft 5 is also moved axially. As the
eccentric peg 9 is located in its intermediate positions
(not shown) to the side of the toothbrush shaft 5, the
rocker 11 would also have to be moved laterally, but
this is not possible since the toothbrush shaft 5 is
laterally fixed. Instead of a sideways movement, the
rocker 11 performs a rocking movement which is possible
since the sliding block 10 is curved in-to an arc on two
lateral faces 27, 28 and the toothbrush shaft 5 runs
beneath the sliding block 10, as viewed in Figure 6. A
rocking moment is thus produced when the sliding block
10 in its recess 15 presses the rocker 11 to the side so
that the rocker 11 rocks about the toothbrush sha~t 5
and thus rotates the toothbrush shaft 5 accordingly,
Flgure 7 illustrates tha arc-shaped lateral faces 27, 28
of the sliding block 10. The rocker 11 can thus assume
the rocked position in the illustrated position of the
eccentric peg 9, rotated by 90 from Figure 6, so that
it does not have to move to the side.
