U.S. patent application number 08/817113 was filed with the patent office on 2001-12-06 for toothbrush.
Invention is credited to WEIHRAUCH, GEORG.
Application Number | 20010047556 08/817113 |
Document ID | / |
Family ID | 6530216 |
Filed Date | 2001-12-06 |
United States Patent
Application |
20010047556 |
Kind Code |
A1 |
WEIHRAUCH, GEORG |
December 6, 2001 |
TOOTHBRUSH
Abstract
In a plastic toothbrush in which the substantially rigid brush
head is connected by means of a spring part to the substantially
rigid handle and the spring part is embedded in the plastic, a
construction advantageous from the manufacturing, use and
environmental standpoints is obtained in that the spring part is
made at least preponderantly from plastic with a higher modulus of
elasticity than the plastic surrounding it.
Inventors: |
WEIHRAUCH, GEORG;
(WALD-MICHELBACH, DE) |
Correspondence
Address: |
ANTONELLI TERRY STOUT AND KRAUS
SUITE 1800
1300 NORTH SEVENTEENTH STREET
ARLINGTON
VA
22209
|
Family ID: |
6530216 |
Appl. No.: |
08/817113 |
Filed: |
April 29, 1997 |
PCT Filed: |
September 1, 1995 |
PCT NO: |
PCT/EP95/03442 |
Current U.S.
Class: |
15/167.1 ;
15/143.1 |
Current CPC
Class: |
A46B 5/0062 20130101;
B29L 2031/425 20130101; A46B 2200/1066 20130101; A46B 5/007
20130101 |
Class at
Publication: |
15/167.1 ;
15/143.1 |
International
Class: |
A46B 005/02; A46B
009/04 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 7, 1994 |
DE |
P 44 35 888.1 |
Claims
1. Toothbrush with a one-piece, plastic injection moulded brush
body, comprising a substantially rigid head receiving the bristles,
a substantially rigid handle and a tapered neck connecting them,
which has a spring part made from a material with a higher modulus
of elasticity than the plastic of the bristle body, characterized
in that the spring part (4) is at least preponderantly made from
plastic and is at least partly embedded in the plastic of the brush
body, accompanied by the formation of the neck (3).
2. Toothbrush with a one-piece, plastic injection moulded brush
body, comprising a substantially rigid head receiving the bristles,
a substantially rigid handle and a tapered neck connection them,
which has a spring part made from a material with a higher modulus
of elasticity than the plastic of the bristle body, characterized
in that the the spring part (4) is at least prepon derantly made
from plastic and at least partly envelops the plastic of the brush
body, accompanied by the formation of the neck (3).
3. Toothbrush according to claim 1 or 2, characterized in that the
spring part (4) is exclusively made from plastic.
4. Toothbrush according to claim 1 or 2, characterized in that the
spring part (4) is made from a filled plastic.
5. Toothbrush according to claim 4, characterized in that the
fillers are provided in a proportion of 1 to 30 vol. %.
6. Toothbrush according to claim 4 or 5, characterized in that the
spring part (4) is made from the same plastic as the brush
body.
7. Toothbrush according to one of the claims 4 to 6, characterized
in that the spring part (7) is made from fibre-reinforced
plastic.
8. Toothbrush according to claim 7, characterized in that the
spring part (4) is made from glass fibre-reinforced plastic.
9. Toothbrush according to claim 1 to 8, characterized in that the
spring part (4) has a flat, polygonal, round or oval
cross-section.
10. Toothbrush according to one of the claims 1 to 8, characterized
in that the spring part (4) has a T, I or U-cross-section.
11. Toothbrush according to one of the claims 1 to 10,
characterized in that the spring part (4) has a higher moment of
inertia than the remaining cross-section of the neck (3).
12. Toothbrush according to one of the claims 1 to 11,
characterized in that the spring part (4) essentially extends over
the entire length of the tapered neck (3).
13. Toothbrush according to one of the claims 1 to 12,
characterized in that the spring tension of the spring part (4) is
adjustable through the choice of the plastic and/or the fillers
and/or its cross-section.
14. Toothbrush according to one of the claims 1 to 13,
characterized in that the spring part (4) has projections (6, 7)
transversely to its extension.
15. Toothbrush according to claim 14, characterized in that the
projections (6, 7) extend up to the surface of the plastic
enveloping the spring part (4).
16. Toothbrush according to claim 15, characterized in that the
projections (6, 7) serve as information carriers (8).
17. Toothbrush according to claim 16, characterized in that the
projections (6, 7) are shaped as information carriers (8) at least
in the area thereof in the surface of the plastic enveloping
them.
18. Toothbrush according to claim 14, characterized in that the
projections (6, 7) serve as anchoring means for the spring
part.
19. Toothbrush according to one of the claims 1 to 18,
characterized in that the spring part (4) with its elongated
surfaces (9) is located in the surface of the enveloping
plastic.
20. Toothbrush according to one of the claims 1 to 19,
characterized in that in the gripping area of the handle (2) is
embedded at least one gripping element (10, 11) made from a plastic
with a higher friction coefficient and/or higher elasticity than
the plastic surrounding it.
21. Toothbrush according to one of the claims 1 to 20,
characterized in that the gripping element (10, 11) is made from an
elastomer.
22. Toothbrush according to claim 21 or 22, characterized in that
in each case one gripping element (10, 11) is provided on the top
and bottom of the handle (2).
23. Toothbrush according to one of the claims 21 to 23,
characterized in that the gripping elements (10, 11) are provided
with a friction-increasing profile (14) on their exposed surface
(12, 13).
24. Toothbrush according to one of the claims 21 to 23,
characterized in that the two gripping elements (10, 11) are in
contact with one another or pass in one piece into one another in
the interior of the handle (2).
25. Toothbrush according to one of the claims 1 to 24,
characterized in that the spring part (4) and/or the gripping
elements (10, 11) are preshaped as shaped bodies and injected round
with the plastic forming the brush body.
26. Toothbrush according to one of the claims 1 to 24,
characterized in that the brush body, spring part (4) and gripping
elements (10, 11) are manufactured in a multicomponent injection
moulding process.
Description
[0001] The invention relates to a toothbrush having a one-piece,
plastic injection moulded brush body comprising a substantially
rigid head receiving the bristles, a substantially rigid handle and
a tapering neck connecting said two parts, which has a spring part
made from a material with a higher modulus of elasticity than the
plastic of the brush body.
[0002] Toothbrushes are mainly used for cleaning the teeth and the
interdental gaps, but frequently also have to exercise a massaging
action on the gums or the marginal areas thereof. The latter action
has more particularly led to special constructional measures on
toothbrushes. These include the construction of a resilient
connection between the brush head and the handle, because, for
stability reasons, they are made from a comparatively rigid
plastic, generally by injection moulding.
[0003] Various constructions are known for obtaining a resilient
connection between the brush head and the handle. According to FR 1
247 433 the head is "split" longitudinally down to the handle area
and the ledge-like parts covered with bristles are overengaged by a
locking ring, by means of which the free length of the ledges and
consequently the flexibility of this more elastic area than the
handle can be adjusted. This construction is complicated from the
design and use standpoints. Due to the gaps which exist it is
subject to hygienic objections. Much the same applies for another
construction (U.S. Pat. No. 4,520,526), in which the toothbrush is
weakened in the transition area between the head and the handle by
recesses in the plastic, so as to give said area a greater
resilience. Here again dirt, toothpaste residues, bacteria, etc.
can be deposited. Much the same applies for constructions in which
the transition area is provided with pronounced profilings (EP 0
281 017, WO 93/15 627).
[0004] Therefore from the hygienic standpoint preference is given
to those constructions in which the transition between the brush
head and the handle is of a substantially smooth-walled nature,
although a spring action is obtained. Thus, it is known (DE 38 40
136) to insert a metal leaf spring in the transition area between
the handle and the brush head and to embed said spring completely
in the plastic. With the leaf spring, which has a higher modulus of
elasticity than the plastic surrounding it, it is possible to
ensure a moving back of the toothbrush in the case of excessive
pressure, as well as a constant, adequate pressure application when
the toothbrush is correctly guided.
[0005] Even though this construction with a metallic leaf spring is
largely satisfactory from the use standpoint, it still suffers from
a number of disadvantages. It leads to the manufacturing problem
that the leaf spring must be injection moulded into the plastic,
which requires corresponding constructional precautions on the
injection mould. In addition, due to their extremely thin wall
thickness leaf springs during the manufacturing sequence are
difficult to handle both manually and with manipulators and can
only be positioned with difficulty in the injection moulding
machine. They also form no connection with the surrounding plastic.
Thus, on springing out in the vicinity of the edges of the leaf
spring necessarily compressive and shear stresses act on the
surrounding plastic, which can lead to breaking or the
cross-section in the transition area between the brush head and the
handle must be overdimensioned. However, particularly at this point
an especially slender shape is desired, so that it is possible to
guide the necessary movements of the toothbrush even with the mouth
closed. Finally, all metallic materials are undesired in the oral
hygiene sector, even if as in the present case they are not
exposed. They also represent a scarcely solvable problem during the
recycling of toothbrushes, which has considerable importance due to
the mass consumption thereof. A type-pure separation of the
materials would require a complete crushing of the toothbrush. In
view of the small weight proportion of the metal the costs involved
would hardly be acceptable. Finally, it has already been proposed
(WO 93/15 627, DE 38 40 136) to make the brush body extremely
slender in the vicinity of the neck and in this way obtain a spring
action. A rubber-elastic elastomer is then injected around the very
thin cross-section. The plastics normally used for the brush body
do not have an adequate modulus of elasticity, in order to obtain
an adequate and in particular permanent spring action. In addition,
the transitions from the handle or head must be extremely steep, so
that at the transitions breakages can easily occur. If an
adequately high modulus of elasticity is provided, then very
high-grade plastics must be used for the brush body. This is
unacceptable from the costs standpoint with mass produced articles,
like toothbrushes.
[0006] The problem of the invention is to propose a toothbrush,
which is simple to manufacture, favourable to use and also
environmentally friendly. It must also be possible to easily adjust
the spring action.
[0007] According to the invention this problem is solved in that
the spring part with the higher modulus of elasticity than the
plastic of the brush body is at least preponderantly made from
plastic and is at least partly embedded in the plastic of the brush
body, accompanied by the formation of the neck. Instead of this,
the spring part can also at least partly envelop the brush body in
the neck area.
[0008] The invention firstly leads to the advantage that the
toothbrush is entirely made from plastic and consequently no
disposal problems occur. In addition, any metal fraction, which is
undesired in the oral hygiene sector, is avoided. Finally, such a
toothbrush can be inexpensively manufactured, e.g. in twocomponent
injection moulding processes, embedding processes, etc. As the
plastic spring part is embedded in plastic, there is no alien
material pairing and as a function of the plastics there can even
be an integral joint. Only the spring part need be made from
high-grade plastic, whereas the brush body can be made from
conventional, inexpensive plastics.
[0009] The spring part can be made exclusively of pure or a filled
plastic, the fillers being present in a proportion of 1 to 30 vol.
%.
[0010] Preferably the spring part is made from a fibre-reinforced
plastic, use being preferably made of glass fibres. Such a spring
part can be separately injection moulded and then inserted or
injection mould in integrated manner in the injection mould for the
toothbrush. However, the spring part can also be produced by
injection moulding round the neck area of the brush body.
[0011] The spring part can have a flat, polygonal, round or oval
cross-section, but also a U, T or I-cross-section, so as in this
way to influence the nature of the springing out of the brush head.
This springing out can not only be provided counter to the pressure
on the tooth surface, but also at least to a limited extent
transversely thereto or in any random direction.
[0012] Advantageously the spring part has a higher moment in
inertia than the remaining neck cross-section and extends
substantially over the entire brush body neck length.
[0013] The construction according to the invention gives the
possibility of adjusting the spring tension of the spring part
through the choice of the plastic and/or the fillers and/or its
cross-section. This spring tension adjustment can take place within
wide ranges. Thus, for toothbrushes for children a smaller
resilience is used than for toothbrushes for adults. Compared with
all known constructions there is a material and consequently cost
saving. The neck can also be made extremely slender with gentle
transitions between the handle and the head.
[0014] In a further preferred construction the spring part has
projections transversely to its extension. These projections can
initially serve as simple positioning aids in the injection mould
and also for maintaining position during moulding. In addition, the
spring part is "centred" and anchored in the surrounding plastic
mass.
[0015] The invention more particularly offers the possibility for
the projections to extend up to the surface of the plastic
enveloping the spring part. This also leads to the manufacturing
advantage that the spring part can be positioned directly at the
mould wall and no position aids have to extend into the cavity.
These projections are not prejudicial on the surface, because they
are also made from plastic.
[0016] In the area on which they appear on the visible side, said
projections can in fact fulfil a further function, namely as
information carriers, e.g. for manufacturers' marks, publicity
slogans, use information, etc. and can be shaped as such.
[0017] In a further advantageous construction the spring part with
its elongated surfaces is located on the surface of the enveloping
plastic.
[0018] This simultaneously provides a large-surface support of the
spring part in the injection mould for the handle and head of the
toothbrush. In particular the spring part with said elongated
surface on the one hand and the projections located on the opposite
side on the other can be fixed between the two injection mould
parts and therefore accurately positioned. By a corresponding
colouring of the spring part, its spring function can be optically
indicated.
[0019] According to another advantageous embodiment, in the
gripping area of the handle is embedded at least one gripping
element made from a plastic with a higher friction coefficient than
that of the surrounding plastic.
[0020] For optical and hygienic reasons the handle and head of a
plastic toothbrush are generally made from a plastic with a smooth
and optionally glossy surface, so that the hand is not subject to
particularly good handling characteristics and is not grip-proof.
This disadvantage is increased by the spring characteristic in the
vicinity of the brush neck, because the head performs relative
movements with respect to the handle and consequently the hold of
the fingers on the handle is reduced and the fingers can easily
slip off. This is counteracted by the gripping elements with
increased friction coefficients. They ensure that the fingers have
a firm hold on the handle, so that the toothbrush does not slip
when used.
[0021] Preferably the gripping element is made from an elastomer,
which inherently has a higher friction coefficient than the
thermoplastics normally used for the head and handle.
[0022] The good grip can be further increased in that in each case
one gripping element is provided on the top and bottom of the
handle, so that the thumb gripping the underside also has a firm
hold.
[0023] A further improvement to the good handle action results from
the fact that the gripping elements are provided on their exposed
surface with a friction-increasing profile, which e.g. follows the
shape of the finger tips.
[0024] The two gripping elements on the top and bottom are
preferably in contact in the interior of the handle, which
facilitates their insertion in the injection mould. However, they
can also pass into one another in one piece. In conjunction with
the construction of the gripping elements from an elastomer, a very
elastic gripping surface is obtained.
[0025] Finally, the spring part and the gripping elements are
preshaped and injected round by the plastic forming the handle and
head.
[0026] In place of a separate production of the parts and
subsequent embedding or injecting round, it is also possible to
produce the brush body, spring part and gripping elements in a
multicomponent injection moulding process.
[0027] The invention is described in greater detail hereinafter
relative to non-limitative embodiments and the attached drawings,
wherein show:
[0028] FIG. 1 A longitudinal section through a toothbrush without
bristles.
[0029] FIG. 2 A larger-scale section in area X of FIG. 1.
[0030] FIG. 3 A plan view of the sectional representation of FIG. 2
from below.
[0031] FIG. 4 A section through another embodiment corresponding to
FIG. 1, but in broken away form.
[0032] FIG. 5 A longitudinal section through another
embodiment.
[0033] FIG. 6 A larger-scale detail of FIG. 5.
[0034] FIG. 7 A section VII-VII according to FIG. 6.
[0035] The toothbrush according to FIG. 1 comprises a head 1 with
not shown bristles and an elongated handle 2, which are
interconnected by means of a slender transition area 3 forming the
neck.
[0036] In the constricted transition area 3 from the brush head 1
to the handle 2 is embedded a spring part. For example the entire
toothbrush is produced by injection moulding and injection takes
place round the spring part 4. As can in particular be gathered
from FIG. 2, the spring part 4 is consequently surrounded on all
sides by plastic, so that the toothbrush offers a unitary
exterior.
[0037] The spring part 4 has a higher modulus of elasticity than
the surrounding plastic of the brush body, but is preponderantly
made from plastic, preferably glass fibre-reinforced plastic, and
can be constructed similar to a leaf spring or wire rod, but can
also have an oval or polygonal cross-section. Thus, the toothbrush
neck 3 is given a resilience approximately perpendicular to the
longitudinal extension of the brush body, but by a corresponding
cross-sectional shape a more or less marked resilience can also be
obtained in other directions.
[0038] In the embodiment shown in FIG. 1 the spring part has a
flat, sheet-like main part 5, which is provided in the vicinity of
its ends with projections 6 and 7 running transversely to its
extension. These projections can be used for posi tioning purposes
within the injection mould and preferably project up to the surface
of the neck 3 and in this way, as shown in FIG. 3, can additionally
serve as carriers for information 8. This information can be
produced by corresponding impressions in the mould at the time of
producing the spring part 4.
[0039] The embodiment of FIG. 4 differs from that of FIG. 1 in that
the spring part 4 is located with the surface 9 extending in the
longitudinal direction in the top surface of the neck 3 between the
head 1 and the handle 2. In correspondingly flat manner the
preshaped spring part 4 can be supported in the injection mould for
injecting round with the plastic forming the head 1 and the handle
2. Through suitable colour differences the function of the spring
part can be optically indicated to the user. Thus, the toothbrush
constructed according to the invention can be differentiated from
some other toothbrush.
[0040] The handle 2 has in its thickened gripping area gripping
elements 10, 11 embedded in the plastic, the upper gripping element
10 having a relatively large gripping surface and the lower
gripping element 11 a somewhat smaller gripping surface. The
gripping elements are made from an elastomer and can additionally
be provided on their free surface with a friction-increasing
profile, e.g. in the form of grooves 14, which preferably run in
closed, concentric ovals and are consequently adapted to the shape
of the finger tips. The gripping elements 10 and 11 are in
engagement with one another in the interior of the handle 2, so
that they can be perfectly supported in the injection mould for
injecting round with the plastic of head 1 and handle 2.
[0041] In the embodiment according to FIG. 5 the spring part 4 is
constructed as a type of sleeve 15, which in the transition area 16
envelops the plastic of the brush body. Manufacture preferably
takes place in the two-component injection moulding process, in
that the brush body formed form the head 1, handle 2 and transition
area 16 is firstly injection moulded in a mould. Subsequently the
transition area 16 is injected round in the same mould with the
plastic forming the spring part 4 and in this way the neck 3 is
formed. The spring part 4 has a higher modulus of elasticity than
the plastic in the transition area 16 of the brush body enveloped
by it. The gripping elements 10, 11 are subsequently moulded in the
two-component injection moulding process, so that they are
constructed in one piece.
[0042] In all the embodiments the spring part 4 extends over the
entire transition area 3, 16 into the head 1 or the handle 2, so
that there is also an adequate stability at the transitions.
* * * * *