Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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The invention relates to an electric toothbrush of
the type having a drive mounted in the handle and a cleaning
element supported by the handle.
An electric toothbrush is known from the PCT
application W084/02453 (published July 5, 1984 in the name of
Rosenstatter~, comprising a handle with a drive and a brush
shaft. A bristle head is formed on the brush shaft, said
head being mounted so as to be rotatable about a rotational
axis directed perpendicularly to the brush shaft. The
disadvantage of the known toothbrush is that the bristle head
can penetrate the spaces between the teeth only with
difficulty.
In addition, a toothbrush is known from German OS 29
28 449 whose brush head is connected with the shaft of the
toothbrush by a coil spring. The brush head can execute
twisting and tilting movements during the tooth cleaning
process by means of the coil spring suspension. Admittedly,
the bristle edges of known toothbrushes permit penetration of
the spaces between the teeth because the tooth cleaning head
can tilt to match the contours of the surfaces of the teeth,
but the defect of these toothbrushes lies in the fact that
the cleaning motion provided by the continuous rotation of
the tooth cleaning head is not present. In other words, the
bristle head according to German OS 29 28 449 cannot rotate
fully and continuously.
In addition, a toothbrush is known from EP-A2 66 259
which comprises a bristle head which is tiltably mounted like
a rocker. The rotational axis of the bristle head in this
toothbrush runs transversely to the lengthwise axis of the
brush. The brush head
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can tilt forward and backward during the horizontal polishing
movement~ becauce of the rocker mounting, thereby slightly
penetrating the spaces between the teeth. In -this toothbru~3h too,
there is no rotary polishing motion.
I,ike the toothbrush according to EP-A2 66 259, a
toothbrush is known from EP-Bl 23 407 and FR-AS 25 50 068 which has
its brush head rotatably mounted on an axis perpendicular to the
lengthwise axis of the toothbrush. The toothbrush according to
FR-AS 25 50 068 in addition comprises a spring rod which aligns the
10 bruæh head in a preferred basic position. In the two last mentioned
toothbrushes as well, the rotary polishing motion is likewise not
provided,
The goal of the invention therefore is to provide an
electric toothbrush whose bristle head offers a considerable
cleaning action on all curved parts of the tooth surfaces, gingival
pockets, gingival furroNs, and the spaces between the teeth.
The invention relates to an electric toothbrush comprising
a heandle and a tooth cleaning head. The tooth cleaning head has a
body and cleaning element structure mounted in annular array on the
20 body. A drive i~ provided in the handle for driving the tooth
cleaning head in rotation about a rotational axis generally coaxial
with the cleaning element structure, and an articulation structure
is coupled between the drive and the cleaning element structure, the
articulation structure being disposed adjacent the center OI gravity
of the tooth cleaning head and permitting tilting movement of the
cleaning element structure relative to the body as the tooth
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cleaning head is driven in rotation about its rotational axis by the
drive.
Thu3, the invention provides an electric toothbrush with a
bristle or brush head or a tooth clsaning head i9 provided,
comprising an articulated device which, in addition to complete and
continuou~ rotary motion of the cleaning head, also permit~ tilting
out of the basic position. In other words, in addition to the
rotary motion, the cleaning head has additional degrees of freedom.
Depending on the design of the articulation device, one or two
additional degree~ of freedom are provided, 90 that the cleaning
head can readily adjust to all the
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contours and spaces between the teeth automatically during the
polishing motions. Thus, the cleaning head, running at top speed, is
pivotable relative to the lengthwise axis without the toothbrush or its
lengthwise axis having to adopt a different directional orientation.
When the toothbrush with the tooth cleaning head according to the
invention is guided along the rows of teeth, the leading edge of the
cleaning element, for example in the form of a crown of bristles or
rubber cups, automatically pivots into the adjoining spaces between the
teeth because the force with which the cleaning head against the necks
of the teeth evokes forces acting from the outside which cause the
bristle crown by lever action to pivot into the spaces between the
teeth. In other words, the position of the cleaning head adapts itself
from a basic working position to the different curvatures of the tooth
surfaces. Qs a result OI the improved mobility of the cleaning head,
the cleaning action in addition to the considerable polishing effect
caused by the continuous rotation of the head, is considerably
increased.
The articulation device can be provided between the rotational axis and
the tooth cleaning head, with the rotational axis being permanently
located on the lengthwise axis of the toothbrush in this c~se.
Otherwise, it is possible to provide the articulation device between the
lengthwise axis and the rotational axis and to mount the cleaning head
preferably rigidly on the rotational axis. In all cases, the same
advantageous tilting action is achieved, i.e~ all of the embodiments of
the articulation arrangement lie within the scope of the invention, in
which the cleaning head itself or together with the rotational axis can
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be tilted through a certain range of angles out of its basic working
position. The tooth cleaning head or the brush head is there~ore
mounted in such fashion that it is pivotable under inhomogeneous
external force application up to a maximum angle of approximately 20 to
30. As a result, considerably improved cleaning of the teeth is
achieved without requiring additional effort on the part of the user.
As a fre~uency range for the circular motion with which the brush head
is rotated, 5 to 50 Hz, especially however 7 to 10 Hz, is proposed. At
a higher frequency, the bristles harden more rapidly and the brush
head is no longer in a position at high speeds to adapt sufficiently to
the contours of the teeth. At lower frequencies, on the other hand,
the drive becomes irregular and tends to generate imbalances.
In an especially preferred embodiment, the brush head is a crown plate
rotating about its axis of symmetry. The term "crown plate" within the
scope of the invention defines a plate-shaped structure on which a
crown consisting of cleaning means or cleaning elements is mounted,
with cleaning means being understood to mean, in addition to bristles,
the rubber cups, described in greater detail hereinbelow. It is
characteristic of this embodiment that the crown plate rotate about its
axis of symmetry, in other words it retains its center of gravity, and
the circular motion is accomplished through its own rotation.
In particular, outwardly pointing bristles can be mounted vertically or
diagonally on the plate9 whereby in the latter case a greater effective
area is produced ~or the same plate diameter. According to another
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recommendation of the invention, the crown plate is free of bristles in
the vicinity of the rotational axis if it is not desirable for the central
bristle areas to collect and concentrate in the spaces between the teeth
during rotation. As the bristle head is pressed against the teeth9 the
outer bristles bend outward and the inner bristles penetrate more
deeply into the spaces between the teeth. If a bristle head completely
covered with bristles is employed, the inner bristles ser~re primarily to
clean the spaces between the teeth while the outer bristles act on the
gingival margin. On the other hand, the bristle-free central area
creates the opportunity to apply the toothpaste in the area of the crown
plate which is in the vicinity of the rotational axis, said toothpaste
being uniformly distributed into the peripheral zones during operation,
i.e. during rotation of the crown plate.
In another feasible version of the crown plate, a frustroconical jacket
which opens outward is mounted on the plate, which also consists of an
elastic material, rubber for example. Experience indicates that such
'1rubber cups" produce better cleaning than heads designed with
bristles. The opening in the cup can be used to hold toothpaste, with
the latter being uniformly spread over the teeth and forced into the
spaces between the teeth by the pressure exerted during operation,
which results in a spreading of the frustroconical jacket because of its
elasticity. A further improvement to this crown plate consists in
closing the outwardly open frustroconical jacket with a membrane on
which bristles are mounted. The membrane can change its shape and
structure by virtue of its intrinsic elasticity and adapt in this way to
the surfaces of the teeth or the spaces between the teeth. In addition,
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the eïasticity of the rubber cup supporting the membrane allows the
opening width to be varied as a function of application pressure, so
that the proposed embodiment combines both the advantages of the
rubber cup with those of a crown plate fitted with bristles.
In addition, when a crown plate is used, a frequency of 5 to 50 Hz is
proposed, whereby the best cleaning results can be achieved in the 2
to 15 Hz range for the reasons set forth above. Extending the
frequency range downward is based on the fact that when a crown plate
is used the center of gravity remains fixed in space even during the
operating phase and the resultant imbalances are therefore much less
than when the brush head moves in a circular fashion.
The gingival margin which defines the transition between the tooth and
the gum is a curved line whose midpoint corresponds roughly to a circle
with a diameter of approximately 1.5 cm. The best possible cleaning of
this area can therefore be achieved if the circular motions of the brush
head is so dimensioned that it describes a circle with a diameter of 1.5
cm because then the bristles move essentially along the gingival margin
and clean the latter optimally.
In a preferred embodiment, it is proposed to subject the teeth to a
cleaning process from both sides, i. e. from inside and outside
simultaneously, with two brush heads being applied, located some
distance apart and facing one another, whereby the space between them
is made smaller than the average thickness of the teeth. The bristle
heads of the toothbrush can then be mounted in the form of a forked
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head. One of the essential advantages is that all the teeth can be
cleaned in approximately h~lf the time.
According to one advantageous embodiment, a spring element is
provided which moves the cleaning head back into the basic operating
position after the external action of force on the cleaning elements is
removed. The user therefore can advantageously predict the position
of the cleaning surface after removing the cleaning head from the teeth
and can readily position the cleaning head directly at a new point, The
cleaning head therefore does not execute any uncontrolled movements
when the cleaning elements are not in contact with the teeth. The
spring constant of the spring element is so dimensioned that the
cleaning head assumes a specific position in the freely rotating state
and, moreover~ the tilting movements are not impeded as it moves over
the surface of the teeth.
The invention is described hereinbelow in greater detail with reference
to the drawing.
Figure 1 is a side view of a crown plate fastened to a brush shaft;
Figure 2 is the top view of the embodiment shown in Figure l;
Figure 3 is a tooth cleaning head according to the invention with a
cross ball joint;
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Figure 4 is a section along line AB in the support for the cleaning
elements of the tooth cleaning head in Figure 1;
Figure 5 is a lengthw~se section through a brush haad of a
toothbrush;
Figures 6A, 6B, and 6C are embodiments of leaf springs; and
Figure 7 is a lengthwise s~ction through another embodiment of the
tooth cleaning head according to the invention.
Only the forward part of brush handle 44 is shown in the electric
toothbrush in Figure 1, on which shaft the brush head or crown plate,
marked tooth cleaning head 1, is rotatably mounted, with its rotational
axis 3 running radially to brush shaft 1. During each phase of its
motion, crown plate 1 remains in the same plane running tangentially to
the covering of brush shaft 44. After the drive is switched on, crown
plate 1 is set rotating by means of power transmission means not shown
here. Cleaning elements 10, e . g. bristles, are mounted approximately
vertically on its surface, in such fashion that an area around rotational
axis 3 is left free.
The toothbrush according to the invention is used in such fashion that
before or after the drqve is switched on, crown plate 1 is applied with
light pressure against the teeth and gums by means of bristles 10,
possibly after applving toothpaste, especially in the ~icinity of
rotational axis 3, and then moved back and forth by means of brush
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shaft 44. The gingival margin is cleaned especially thoroughly when
the circles described by bristles 10 have an average diameter of
approximately 1. 5 cm, since in this case the motion occurs essentially
along the gingival margin. A value of 2-15 Hz is proposed as especially
favorable for the rotational frequency.
Figure 2 is the same embodim~nt viewed from above. Crown plate 1 is
provided with bristles 10 on one side (the lower side) and connected on
its opposite side by means of a rotational axis 3 with brush shaft 44 in
such fashion that crown plate l in its totality can tilt about an axis
perpendicular to brush shaft 44 and rotational axis 3. For clarity's
sake, a crown plate 1 in the tilted position is showrl by the dashed
lines. It is critical to the invention that, on the one hand, connection
with the drive of the toothbrush is provided even during pivoting, i.e.
in every possible position, and, on the other hand, that the pivoting
motion be evoked by nonuniform application of force to the surface of
crown plate 1. During practical application it occurs as a rule that
crown plate 1 partially rests against a tooth and spans a space whereby
it is subjected to an asymmetric, i . e. inhomogeneous outer force,
causing crown plate 1 to pivot, in such fashion that the part which is
in the vicinity of the tooth is moved toward brush shaft 44 and ths
other part consequently moves away from it. As a result, crown plate
l and the bristles 10 located thereon can penetrate the spaces between
the teeth better and clean them. lNhen the force application just
described is terminated, the crown plate returns to its original position
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The result is an electric toothbrush which permits much more thorough
and more complete cleaning of the teeth while simultaneously avoiding
injury to the g~um.
Figure 3 shows an embodiment of a tooth cleaning head 1 of a
toothbrush with an articulation device which comprises a cross ball
joint. The cross ball joint consists of a ball shell 5, a ball joint 4,
pins 6, and annular groove 7. Rotational axis 3 is provided on ball
joint 4, which sets tooth cleaning head 1 rotating . B all shell S is
machined into a support 2, as for example crown plate 2 described
above, said support as shown in Figure 3 having bristles 10 in the form
of a bristle crown thereon. In order to prevent ball joint 4 from
penetrating ball shell 5 as a result of rotation of rotational axis 3, the
pins 6 located opposite one another are provided. Pins 6 slide in
annular groove 7, so that, based on Figure 1 as shown, rotational axis
3 can make movements to the left and right9 as well as in snd out of
the plane of the drawing. The articulaffon device in the simplest case
can also be designed as a pin joint, permitting one degree of freedom.
Figure 4 is a section through support 2 along line AB, and Figures 3
and 4 are intended to show that the articulation device shown can be
moved in the directions indicated. In other words, the articulation
device has two degrees of freedom, but tooth cleaning head 1 can
nevertheless be set rotating by means of pins 6. Power transmission
then occurs from rotational axis 3 to pins 6, which in turn transfer the
forces to the side walls of annular grooves 7. Aperture cone 8 is cut
out at the point of entry of rotational axis 3 into support 2, so that
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rotation~l axis 3 can be moved into the directions described. Rotational
axis 3 is positionable at any desired point within aperture cone 8, if
pins 6 do not strike limiting edge 41 beforehand. Tooth cleaning head
1 shown in Figure 3, as described above, preferably has a symmetrical
round shape and the articulation de~rice rests on the axis of symmetry
of the cleaning head.
On the underside of support 2, bristles 10 are provided in the form of
a bristle crown. Relative to the lengthwise axis of tooth cleaning head
1, bristles 10 run at an angle o~ outward. The bristle crown thus
forms a frustroconical jacket. Preferably angle~C is within a range of
25. In forward area 11 of the bristle edge, the bristles travel a short
distance parallel to the lengthwise axis of tooth cleaning head 1.
Bristles 10 are cut off here for example, or bent over after heaffng,
and directed in the direction shown. It is also possible, however, to
leave the pointed edge of the bristles with reference 12, standing
~shown shaded). However the segment which runs in a straight line in
the forward area of the bristles has the advantage that the outermost
bristles cannot penetrate the gums or the gingival pockets as easily.
Preferably the diameter of the cleaning area 40 at the tips of the
bristles is in the vicinity of 15 mm. In other words, the curvature of
the circumferential edge of cleaning area 40 lies in the range of
curvature of the gingival margin. In addition, the length of bristles 10
and the diameter of support 2 is 10 mm. On the inside, the bristle
crown has bristles 10 cut away, producing a cavity 14. Cavity 14 can
be used to accommodate toothpaste or one or more knobs of elastic
material, which have their tips protruding out of the opening in the
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s~avity and can be used to massage the gums. The knobs are
preferably made somewhat shorter than the length of bristles 10, so
that the knobs (not shown) will contact the gums slightly later than
bristles 10 after gentle pressure is applied to the cleaning head.
Instead of bristles 10, cleaning elements in the form of elastic materials
can also be used, in which for example the bristle crown consists of a
frustroconical section made of rubber. The frustroconical section can
have the same details as described above in conjunction with bristles
10 .
When cleaning head 1 with cleaning area 40 is applied to the surface of
a tooth, the position of cleaning area 40 automatically adapts to the
contour of the surface of the tooth because of the cross ball joint. Due
to the continuous polishing motion and the adaptability of the position
of cleaning area 40 with respect to the surface contours of the teeth, a
considerable cleaning effect is achieved. If tooth cleaning head 1
encounters a gap in the teeth during the polishing movements, the
force of the pressure is transmitted in turn via cleaning area 40 to the
surface of the tooth causes tooth cleaning head 1 to tilt into the space
between the teeth. In other words, the cleaning areas 10 which are
located to either side of the joint form lever arms, which exert torques
under load, at the distance from the axis of symmetry on which the
articulation lies. If the two forces to the right and left of the axis of
symmetry are equal, tooth cleaning head 1 will rotate horizontally. On
the other hand, if the force is absent on one side, for example if the
head is traveling over a space between the teeth, cleaning head 1 will
tilt until the bristles strike something once again. Tooth cleaning head
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1 can therefore p~netrate the lower-down spaces between the teeth with
the forward polishing surface edges during rotary cleaning motions,
whereby no area of the too$h surface/ even at the neck of the tooth, is
skipped or omitted. The rotational speed of cleaning head 1 is
preferably variable and the rotational frequency is in the range from 1
to 20 E~z. It is also advisable to design the rotational direction of
cleaning head 1 to be reversible in order to ensure that the cleaning
elements wear uniformly or to improve the handling of the toothbrush.
Figure 3 shows support 2 to be covered by an elastic mater~al 9 on the
top. Material 9 exhibits elasticity which is sufficiently great that it
follows the motions in the rotational axis. Elastic material 9 therefore
on the one hand adopts the function of protecting the joint against the
penetration of dirt and water. On the other hand, the elastic material
exhibits spring characteristics which ensure that tooth cleaning head 1
is pushed back into its basic position when the cleaning elements are
rotating freely and are not in contact with the surface of the tooth. In
this way, the tooth cleaning head will not make any uncontrolled
movements and the user can better estimate the position of cleaning
area 40 before reapplying the head to the teeth.
Figure 5 shows a lengthwise section through the forward æhaft 18 of a
toothbrush 15. A drive shaft 19, comprising a drive gear 20~ rotates
in shaft 18 in a bore. Drive shaft 19 is driven by a motor (not shown)
in the handle of toothbrush 15. The lengthwise axis of toothbrush 15
runs along drive shaft 19. In the forward area of the shaft, a chamber
27 is provided in which a shaft 21 is disposed perpendicularly to the
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lengthwise axis. Shaft 21 is rotatable at the rear end in a bearing 42
and is nondisplacably mounted axially. In Figure 5, shaft 21
corresponds to rotational shaft 3 in Figures 1, 2, and 3. In addition,
shaft 21 comprises a gear 23 with a crown gear 22, which is in mesh
with drive gear 20. As soon as drive shaft 19 is rotated by the motor
(not shown), the power is transmitted to crown gear 22 of gear 23.
seal 24 is provided to prevent dirt or water from penetrating bearing
42 .
A support 2 for bristle tufts 16 is provided on the forward free end of
shaft 21, Support 2 has the form of a ring, with bores 17 to receive
bristle tufts 16 being positioned diagonally outward at a suitable angle.
The connection between support 2 and shaft 21 is provided by a leaf
spring 25 which is shown only in cross section in Figure S, Leaf
spring 25 is fastened by mounting points 26 to the forward free end of
shaft 21. As shaft 21 rotates, support 2 is rotated together with
bristle tufts 16. Instead of bristle tufts 16, rubber knobs or rubber
pins like those described above may likewise be used. Similarly, it is
also possible to supply water through hollow shaft 21 and it is possible
to provide a plurality of supports 2 in the transverse or lengthwise
direction of the shaft, whereby addition~l shafts 21 and gears 23 are
provided. Supports 2 disposed side by side are spaced sufficiently far
from one another that they will not contact one another with their
leading bristle tips when tilted out of their basic working posiffons.
Figure 5 shows the basic working position of support 2. If, as
described ~bove, a unilateral pressure is exerted on the tips of bristle
tufts 16, support 2 will move out of the position shown in Figure 5.
Annular support 2 is cut away in its inside diameter at its upper edge
or its free end to the point where sufficient room is provided for
pivoting and the inside of support 2 does not touch shaft 21. On the
other hand, however, it is also possible to dimension the free space
between support 2 and shaft 21 in such fashion that shaft 21 serves as
a stop and limit to the tilting motion.
Figures 6~, 6B, and 6C show various embodiments of leaf spring 25 in
top view. Leaf springs 25 comprise external and radially e~ctending
retaining ribs 29, which are fastened to the underside of annular
support 2 shown in Figure 5. ~eaf springs 25 have recesses 28 to
allow bristle tufts 16 to pass through. The central section 30 of each
leaf springs 25 is attached to a fastening point 26 at the free end of
shaft 21 and central sections 30 are connected with the outer retaining
ribs 29 by spring segments 31. Leaf springs 25 shown in Figure 6 are
completely flat and are given the shapes shown for example by etching
or stamping. Retaining ribs 299 spring segments 31, and central
segments 30 therefore lie in a single plane so that central segments 30
can be moved into another plane relative to retaining ribs 29, so that
spring elements 31 have the shapes shown in Figure 6. The excess
length, in other words spring elements 31 are longer than the shortest
distance between a retaining lib 29 and a central section 30, makes it
possible to tilt retaining ribs 29 upward or downward relative to the
plane of central sections 30. Since retaining ribs 29 merge with spring
elements 31 independèntly of one another it is possible to tilt one part
of the spFing elements u pward and the other half downward in the
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plane of the drawing. Preferably, two retaining ribs 29 are always
opposite one another so tha~ a line of symmetry is formed around which
support 2 is tiltably mounted. Figure 6A shows spring elements in the
form of a compressed ring. In addition, Figure 6B also shows spring
segments 31 in the form of loops and Figure 6C shows them in the
shape of ribs arranged in the form of a vortex.
Figure 7 shows another embodiment o a tooth cleaning head 1.
Support 2, which holds bristle tufts 16, is connected by struts 33 with
an inner plate 32. Struts 33 extend radially from plate 32 to the inner
edge of support 2. Preferably once again an even number of struts 33
is provided, so that two struts, located opposite one another can form a
rotational axis about which the cleaning head can tilt. Struts 33 are
curved into an S shape according to the direction of the cross section
shown in Figure 7 and extend with excess length into the interior of
support 2. The S shape is produced by the transition from plate 32,
at which struts 33 has a first curved segment, to the second curved
segment, which is formed on the upper edge of support 2. The S
shape or conically inwardly directed path of struts 33 causes plate 32 to
sink into the interior of cavity 43 in support 2. The excess length of
struts 33 and their path makes support 2 pivotable or tiltable about
rotational shaft 3 within a specific angle range from its basic working
position. Struts 33 in this regard simultaneously operate as spring
elements, if they are injection-molded for example together with
supports 2 out of a single piece of plastic. Accordingly, struts 33,
ater tilting of support 2, attempt to resume their shape once again as
deined by the manufacturing process. The spring characteristics of
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struts 33 can be varied by the size and width of 810ts 35 between
stru$s 33 as well as by the thickness of struts 33.
It is likewise possible to provide breakaway points 36 on struts 33 so
that if one of supports 2 should break off inner plate 32 no sharp
edges will be directed toward the gum. In other words the breakaway
points preferably lie inside chamber 27 (see Figure 5) preventing any
contact between broken off strut ends and the gum. Plate 32 also
offers the advantage that the round leading edges prevent any damage
to the gum. In the middle of plate 32, a depression is provided for
example for a rubber knob. In addition it is also possible, as in the
cases described above, to fill interior space 43 completely with a rubber
elastic material so that no toothpaste can enter chamber 27 through slot
35 (see Figure 5). The embodiment of the tooth cleaning head 1 in
Figure 7 also offers the advantage that the articulation device composed
of struts 33 is as close as possible to the cleaning areas. This
improves the positionability of the cleaning head, which is striven for
in the same way as in the embodiments described hereinabove.
In order to fasten tooth cleaning head 1 of Figure 7 to shaft 21,
rotational shaft 3 can be designed for example to have a square cross
section for nonrotational mounting, and can be inserted into a
corresponding bore in the chamber in shaft 21. A projection 38 is
provided for locking, whereby projection 38 is flexibly mounted through
a cut 37 in rotary shaft 3. Cleaning head 1 can thus be mounted on
shaft 3 and replaced if necessary. In contrast to all of the articulation
devices described hereinabove, provided between rotary shaft 3 and
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8uppor1 ~, lt ~s liket~ise possible to mount 6upport 2 ~lgid}y OSl ~haft 21
Qnd to provicle the a~iculstion device instead of be~ing ~2~ It i~ elso
pos8ible to provide the nrticul~tion de~rlse in til~ middle of ~haf~ 21.
I
In Figure 7, etruts 33 which are disposed radi~ on inneI~ plate 32 are
curved ~long the sxis of symmetry or rotational ~ds 3. As ~ result,
inner plate 32 is mounted offset ~n ~he len~thwise direction downward in
inner cham~er 43 of support 2, while in other embodiment8 plate 32 can
al~o be disposed upward outside 6upport 2, In other words ~ the
fastenins~ point of strut 33 or rotational a~s 3 is closer to cie~ning
elements lO than the fastening point of the other end of ~t~ut8 33 to
support 21~ In a modification of this embodiment, it ~s po6s~ble ~or
example to connect plate 32 ~rith the inner ed~e of support 2 in 6uch
fashion that the curvatures of the radi~ ~truts 33, li~e the spring
elemen~s 31 (see ~igure 6) can only he seen in a top v~ew of cle8ning
head 1, whereby ~ll Btl`UtS 33 lie ln the ~ame plane, the orle to which
rotation~l ax~ 3 is perpendicu~ar. In Figure 7, the cur~ture of ~tru~s
33 can only be seen in the section shown. ~t is also po~s~ble to
pro~,ride ætruts 33 whose curvatures are combinations of the possi~ es
shown in Figures 6 and 7. In this connectlon, for example the str-lts
33 ~hown in Figure 7 are also curved laterally.
By di~posing the rota~on or tilting point of bristle he~d 1 ~long the
direction of rotational axis 3, it is possible to ~ary the tilting or
piYoting circle of bri~tle head l, Here, the radius of the tilting or
pi~rotinf~; circle corresponds to struts 33~ The distance between
rotational axis 3 ~nd clea3ling surface 4~, which corresponds to the
2~
lever arm, is not equal here to the radius through which bristle head 1
is pivoted.
In addition, the location of the rotation or tilting point between support
2 and cleaning area 40 offers the advantage that the weights of support
2 and bristles 16 can be balanced. The rotation or tilting point
therefore preferably lies at the center of gravity of bristle head 1 in
order to avoid imbalances during rotation. Freely rotaffng bristle head
1 retains its basic working position even when rotational axis 3 is
horizontal and especially at high rpm.
Instead of the struts 33 shown in Figure 7 it is also possible to provide
an elastic material which connects support 2 with rotational axis 3. The
elastic material then takes over the articulation and spring element
function. For example, such a bristle head 1 is manufactured by a
two-component injection molding process whereby in the first work step,
for example an annular support 2 and rotational axis 3 are formed and
in a second work step the elastic material is injected. In order the
improved the adhesion of the elastic material to support 2, suitable
undercuts, edges, or surface-increasing parts are provided.
The invention is not limited to the embodiments described above but
also allows additional embodiments within the scope. In particular it
has been found advantageous for various applications to allow the
pivoting end or tilting motion of brush head 1 by means OI a bendable
or flexible rotational axis 3. This measure permits eliminating the
articulation designs of the other embodiments and allows advantages in
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terms of manufacturing cost. In these embodiments, a one-piece design
of rotational axis 3 and support 2 by the injection molding process or
the like suggests itself. All of the embodiments of the toothbrush
according to the invention which do not relate to the design of
articulation devices 4, 25, and 33 as disclosed in this document likewise
serve for the advantageous improvement to a toothbrush with a flexible
and/or bendable rotational axis 3.
