U.S. patent application number 13/517693 was filed with the patent office on 2012-12-20 for brush head and method and tool for producing same.
This patent application is currently assigned to Braun GmbH. Invention is credited to Guenther Alschweig, Klaus Amsel, Andreas Birk, Lars Foerster, Ulrich Pfeifer.
Application Number | 20120317738 13/517693 |
Document ID | / |
Family ID | 44863322 |
Filed Date | 2012-12-20 |
United States Patent
Application |
20120317738 |
Kind Code |
A1 |
Birk; Andreas ; et
al. |
December 20, 2012 |
Brush Head And Method And Tool For Producing Same
Abstract
A brush head, particularly a toothbrush head, may have a
plurality of cleaning elements, in particular bristle tufts, which
are anchored by an end section in a brush carrier, wherein the
cleaning elements may be cast with positive engagement in
blind-hole shaped retaining recesses. For producing such a brush
head different cleaning elements, such as bristle tufts may be
fused by heat and may be placed in a mold cavity to be
over-molded.
Inventors: |
Birk; Andreas;
(Kronberg/Taunus, DE) ; Foerster; Lars;
(Kronberg/Taunus, DE) ; Pfeifer; Ulrich;
(Munzenberg, DE) ; Amsel; Klaus; (Schmitten,
DE) ; Alschweig; Guenther; (Eschborn, DE) |
Assignee: |
Braun GmbH
Cincinnati
DE
|
Family ID: |
44863322 |
Appl. No.: |
13/517693 |
Filed: |
June 14, 2012 |
Current U.S.
Class: |
15/167.1 ;
300/21 |
Current CPC
Class: |
B29C 66/8322 20130101;
B29C 66/9141 20130101; A46D 3/005 20130101; A46B 3/06 20130101;
B29C 65/1432 20130101; B29C 65/7841 20130101; B29C 66/137 20130101;
B29C 65/1467 20130101; B29C 66/944 20130101; B29C 66/952 20130101;
B29L 2031/425 20130101; A46D 9/06 20130101; B29C 65/1412 20130101;
B29C 66/9161 20130101; B29C 65/103 20130101; B29C 66/69
20130101 |
Class at
Publication: |
15/167.1 ;
300/21 |
International
Class: |
A46B 9/04 20060101
A46B009/04; A46D 3/04 20060101 A46D003/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 15, 2011 |
EP |
1104870.9 |
Claims
1. A method for producing a brush head in which at least two
different cleaning elements selected from the group consisting of
different types of cleaning elements, distinctive cleaning elements
of the same type and a combination thereof are embedded at one of
their ends at least partially in a bristle carrier, wherein the
ends are fused by heat before embedding, wherein different amounts
of heat are supplied to each of the at least two different cleaning
elements.
2. The method according claim 1, wherein the ends to be embedded
are fused by subjecting them, either individually or in groups, to
a targeted energy flow.
3. The method according claim 2, wherein the ends to be embedded
are subjected to a targeted flow of hot gas or to targeted infrared
radiation.
4. The method according to claim 3, wherein the targeted hot gas
flow that is directed towards the end of the cleaning elements is
created using separate nozzles.
5. The method according to claim 3, wherein the targeted infrared
radiation that is directed towards the end of the cleaning elements
is created using separate reflectors.
6. The method according to claim 1, wherein the at least two
different cleaning elements are held by a carrier part in a
predefined arrangement according to their desired distribution on
the brush head.
7. The method according to claim 1, wherein the different amounts
of heat that are supplied to each of the at least two different
cleaning elements depend on at least one property in which the at
least two different cleaning elements are distinguishable from each
other.
8. The method according to claim 7, wherein the at least one
property in which the at least two different cleaning elements are
distinguishable is the material, the colour, the thickness, the
outer shape, the composition and/or the distance to the source of
the heat.
9. The method according to claim 1, wherein after the ends of the
at least two different cleaning elements have been heated, a
punching tool is moved against the softened ends for reshaping
them.
10. The method according to the preceding claim, wherein, the
punching tool has a flat or a structured surface.
11. A brush head having at least two different cleaning elements
being embedded into a brush head, wherein the at least two
different cleaning elements are fused before embedding using the
method according to claim 1.
12. The brush head according to claim 11, wherein the embedded ends
of the at least two different cleaning elements are arranged in a
common anchoring plane or in different anchoring planes being
arranged above each other.
13. The brush head according to claim 9, wherein the at least two
different cleaning elements include thickenings at the ends to be
embedded after fusing that are different from one another.
14. A device for producing a brush head in which at least two
different cleaning elements selected from the group consisting of
different types of cleaning elements, distinctive cleaning elements
of the same type and a combination thereof are embedded at one of
their ends at least partially in a bristle carrier, comprising a
hot-gas device for applying hot gas to one end of the at least two
different cleaning elements, wherein the hot-gas device comprises a
multiplicity of nozzles for applying varying flows of hot gas.
15. A device for producing a brush head in which at least two
different cleaning elements selected from the group consisting of
different types of cleaning elements, distinctive cleaning elements
of the same type and a combination thereof are embedded at one of
their ends at least partially in a bristle carrier, comprising an
infrared radiation device for applying infrared radiation to one
end of the at least two different cleaning elements, wherein the
infrared radiation device comprises a plurality of reflectors for
applying varying degrees of infrared radiation.
16. The device according to claim 14, wherein the nozzles are
designed to be adjustable with respect to one another.
17. The device according to claim 15, wherein the reflectors are
designed to be adjustable with respect to one another.
18. The device according to claim 14, wherein the device comprises
a temperature-control and/or regulation device for controlling
and/or regulating the hot gas flows exiting from the nozzles
independently of one another.
19. The device according to claim 15, wherein the device comprises
a temperature-control and/or regulation device for controlling
and/or regulating the infrared radiation existing from an infrared
radiation source, independently of one another.
20. The device according to claim 14, wherein the device comprises
a carrier part for holding the free ends of the at least two
different types of cleaning elements or the at least two
distinctive cleaning elements of the same type or the combination
thereof which are not intended to be embedded.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of European Patent
Convention Application No. 11004870.9, filed Jun. 15, 2011, the
substance of which is incorporated by reference in its entirety
herein.
FIELD OF THE INVENTION
[0002] A brush head, in particular a toothbrush head is described,
having a plurality of cleaning elements, in particular bristle
tufts, which are anchored by one of their ends in a bristle
carrier, and wherein the cleaning elements are molded in blind-hole
shaped retaining recesses in a form-closed manner. Further a method
and a tool for producing a brush head, in particular a toothbrush
head, are disclosed in which cleaning elements, in particular
bristle tufts, are fused at one of their ends using heat before
these ends are embedded into the bristles carrier, for instance by
over-molding with a plastic material.
BACKGROUND OF THE INVENTION
[0003] Various methods are known in order to fasten the bristle
tufts in the bristle carrier of toothbrushes, wherein usually
injection-molding from plastic is used. There are known the
so-called anchor tufting methods, in which the bristles of a tuft
are bent, in the shape of a U, around a retaining web which is then
driven into a blind hole. There are also known the so-called
hot-tufting methods, in which the bristle tufts are anchored on the
bristle carrier by means of a forming technique. Usually, the
bristle tufts are melted at their ends to form thickenings and then
are over-molded with plastic or cast into the head when the brush
head is injection-molded.
[0004] Such hot-tufting methods have various advantages, for
example with respect to hygiene, because less bacteria can collect
in the anchoring areas, or also with respect to the cross-sectional
geometry of the bristle tufts, which can be designed in greater
variety than with the anchor tufting methods. But, it is not easy
to generate bristle fields with different properties in different
areas using the hot-tufting method. In order to optimize the
cleaning efficiency of toothbrushes, it may be helpful to provide
different cleaning elements or bristle tufts in different sections
of the bristle field. It can be also helpful support cleaning
elements or bristle tufts in a different manner, for example to
support a portion thereof rigidly in a section of hard plastic and
another portion thereof flexibly in a section of soft plastic. In
addition, it may also be beneficial to melt the ends of differently
composed bristle tufts, for example consisting of different bristle
material, to different degrees, in order to achieve an optimum
anchoring. However, this is difficult using hot-tufting methods
which melt the ends of the tufts after the tufts have been
configured into a bristle field, because the usually required
application of heat to a bristle tuft always also affects adjacent
tuft ends.
[0005] A hot-tufting method is known, in which the bristle tufts
that are held ready in the form of a bristle field are melted at
their ends to such an extent that the melted material of adjacent
bristle tufts combines. The resulting flat support structure, which
connects the bristle tufts, is intended to achieve an increased
pull-out resistance. However, it is difficult in this case to use
bristle tufts of differing bristle materials in order to achieve
different properties in different bristle field sections, since
different types of bristle materials cannot easily be fused
together. This becomes even more difficult when not only bristle
tufts but also differently designed cleaning elements, such as
strips of soft plastic, are to be used and to be combined, for
example, with bristle tufts. In addition, the flat support
structure on the bottom of the bristle tufts inhibits quick filling
of the mold cavities when the bristle carrier is
injection-molded.
[0006] Accordingly, there is a need for a toothbrush head and
manufacturing method thereof, which allows for design flexibility,
material flexibility, and support flexibility.
SUMMARY OF THE INVENTION
[0007] According to one aspect a method for producing a brush head,
for example a toothbrush head, is described in which at least two
different cleaning elements selected from the group consisting of
different types of cleaning elements, distinctive cleaning elements
of the same type and a combination thereof are embedded at one of
their ends at least partially in a bristle carrier, wherein said
ends are fused by heat before embedding, wherein different amounts
of heat are supplied to each of the at least two different cleaning
elements.
[0008] According to another aspect a brush head, for example a
toothbrush head, is described, having at least two different
cleaning elements selected from the group consisting of different
types of cleaning elements, distinctive cleaning elements of the
same type and a combination thereof being embedded into the brush
head, wherein the at least two cleaning elements are fused before
embedding using the method described herein.
[0009] According to another aspect a device for producing a brush
head, for example a toothbrush head is described in which at least
two different cleaning elements selected from the group consisting
of different types of cleaning elements, distinctive cleaning
elements of the same type and a combination thereof are embedded at
one of their ends at least partially in a bristle carrier,
comprising a hot-gas device for applying hot gas to one end of the
at least two different cleaning elements, wherein the hot-gas
device comprises a multiplicity of nozzles for applying varying
flows of hot gas.
[0010] According to another aspect a device for producing a brush
head, for example a toothbrush head is described in which at least
two different cleaning elements selected from the group consisting
of different types of cleaning elements, distinctive cleaning
elements of the same type and a combination thereof are embedded at
one of their ends at least partially in a bristle carrier,
comprising an infrared radiation device for applying infrared
radiation to one end of the at least two different cleaning
elements, wherein the infrared radiation device comprises a
plurality of reflectors for applying varying degrees of infrared
radiation.
[0011] These and other features, aspects and advantages of specific
embodiments will become evident to those skilled in the art from a
reading of the present disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The embodiments set forth in the drawings are illustrative
in nature and not intended to limit the invention defined by the
claims. The following detailed description of the illustrative
embodiments can be understood when read in conjunction with the
following drawings, where like structure is indicated with like
reference numerals and in which:
[0013] FIG. 1 shows a schematic side view of a toothbrush with a
bristle field comprising a multiplicity of bristle tufts which are
anchored in an injection-molded bristle carrier in a hot-tufting
process;
[0014] FIGS. 2A, 2B show a schematic sectional view of a carrier
part for retaining the bristle tufts during the production process;
insertion of the bristle tufts into the carrier part is shown in
FIG. 2A, and the bristle tufts already in place are shown in FIG.
2B;
[0015] FIG. 3 shows a schematic sectional view illustrating the
melting and thickening of the ends of the bristle tufts prior to
the injection process;
[0016] FIG. 4A shows a schematic, perspective illustration of the
bristle tufts situated in the carrier part, which shows the
positioning of the bristle tufts according to the subsequent
arrangement thereof on the brush head;
[0017] FIG. 4B shows, in a partial detail view, an enlarged
sectional view of a bristle tuft in the carrier part according to
FIG. 4A;
[0018] FIG. 5A shows a schematic, perspective illustration of the
melting, through application of hot gas to the ends of the bristle
tufts to be embedded, wherein the hot-gas tool is shown in a
working position;
[0019] FIG. 5B shows, in a partial detail view, an enlarged
sectional view of the bristle tuft in the carrier part according to
FIG. 5A;
[0020] FIG. 6 shows a schematic sectional view of the hot-gas
device and the nozzles thereof at the bristle-tuft ends protruding
out of the carrier part prior to the melting process;
[0021] FIG. 7 shows a schematic sectional view of the hot-gas
device, similar to FIG. 6, the bristle tufts being shown after the
melting and formation of an end-side thickening;
[0022] FIG. 8A shows a schematic, perspective illustration of the
bristle tufts situated in the carrier part with a melted end
section after heat treatment by means of hot gas;
[0023] FIG. 8B shows a partial view of an enlarged sectional view
of a bristle tuft with a melted end section according to FIG.
8A;
[0024] FIG. 9A shows a schematic, perspective illustration of the
mechanical reshaping by means of a punching tool of the melted end
sections of the bristle tufts situated in the carrier part;
[0025] FIG. 9B shows a partial view, in an enlarged illustration,
of a bristle tuft and the reshaping of the melted end section
thereof by means of a section of the punching tool;
[0026] FIG. 10 shows a schematic sectional view through a punching
tool for mechanical reshaping of the melted end sections of the
bristle tufts, wherein the punching tool has different
three-dimensional punching sections which can be positioned;
[0027] FIG. 11A shows a schematic, perspective illustration of the
finished reshaped end sections of the bristle tufts situated in the
carrier part;
[0028] FIG. 11B shows a partial view, in an enlarged sectional
view, of an individual finished reshaped bristle tuft;
[0029] FIG. 12 shows a schematic sectional view, similar to that in
FIG. 6, but with an infrared-radiation device, instead of a hot-gas
device, and the reflectors of the infrared-radiation device at the
bristle-tuft ends protruding from the carrier part prior to the
melting process;
DETAILED DESCRIPTION OF THE INVENTION
[0030] The following text sets forth a broad description of
numerous different embodiments of the present disclosure. The
description is to be construed as exemplary only and does not
describe every possible embodiment since describing every possible
embodiment would be impractical, if not impossible. It will be
understood that any feature, characteristic, component,
composition, ingredient, product, step or methodology described
herein can be deleted, combined with or substituted for, in whole
or part, any other feature, characteristic, component, composition,
ingredient, product, step or methodology described herein. Numerous
alternative embodiments could be implemented, using either current
technology or technology developed after the filing date of this
patent, which would still fall within the scope of the claims. All
publications and patents cited herein are incorporated herein by
reference.
[0031] The brush head and the method for the production thereof as
disclosed herein, as well as an improved tool for the production of
said brush head allow design flexibility, for example, in the
positioning of cleaning elements and allows providing of different
types of cleaning elements, including cleaning elements made from
differing materials. An improved brush head may comprise, for
example, a compact form and is efficient to produce, despite the
complex design of the bristle field thereof, having, for example,
differently designed cleaning elements.
[0032] A method for producing a brush head, in particular a
toothbrush head is shown, wherein different cleaning elements, in
particular bristle tufts, are fused and over-molded at one of their
ends using a plastic material. "Different cleaning elements" as
used herein shall be understood as two different types of cleaning
elements or two distinctive cleaning elements of the same type or a
combination thereof. "Different types of cleaning elements" as used
herein shall be understood as cleaning elements differing at least
in the material they are made from. An example for different types
of cleaning elements may be bristles made of different materials or
bristles and elastomeric elements. "Distinctive cleaning elements
of the same type" as used herein shall be understood as cleaning
elements which are made of the same material, but which are
distinguishable from each other in at least one other property.
Examples for these other properties in which the distinctive
cleaning elements of the same type may differ are e.g. size,
composition, form, outer shape, surface appearance or a combination
thereof. An example for distinctive cleaning elements of the same
type may be bristle tufts having different tuft diameters or having
different tuft geometries, or bristles being tapered or crimpled
compared to unmodified bristles.
[0033] The cleaning elements may be held by at least one carrier
part which has hole-shaped retaining recesses, in which the
cleaning elements may be held during the process of fusing and
over-molding. The position of the cleaning elements in the carrier
part corresponds to the desired relative arrangement thereof with
respect to one another on the brush head. Additionally, said
carrier part may form a wall of the mold cavities, in which the
ends of the cleaning elements extending out from the carrier part
can be over-molded in a multi-component process. Owing to the use
of the carrier part as part of the injection mold, the positioning
of the ends of the cleaning elements to be over-molded as well as
the opening and closing of the injection mold can be executed very
simply and efficiently. The side of the carrier part facing the
ends to be over-molded may form a negative mold for the
cleaning-element-side or bristle-side surface of the bristle
carrier of the brush head.
[0034] The cleaning elements can be transported from a first
injection-molding station in which at least one part of a bristle
carrier and/or a brush head is injection-molded to a second
injection-molding station, in which at least another part of a
bristle carrier and/or a brush head is injection-molded. Further
steps of transportation to additional injection-molding stations in
which additional parts of the bristle-carrier and/or the brush head
can be injection-molded are also applicable to the method as
described herein. Additionally, the cleaning elements may be
located in the at least one carrier part during transportation.
Thus, the aforementioned carrier part, in which the cleaning
elements are arranged, may also used for handling and/or
transporting of the cleaning elements in or between the different
process steps. For example, the cleaning elements, arranged in the
carrier part, may be positioned in various injection molds to mold
different sections of the brush head. In addition, the cleaning
elements may be arranged in the carrier part for the upstream
process step, such as, for example, the thermal treatment for
melting the ends of the cleaning elements to form thickenings. The
carrier part may be also used as a part of the mold cavity for one
or more of said injection-molding stations.
[0035] The thickenings at the cast ends of the cleaning elements
are formed in order to increase the pull-out resistance of the
cleaning elements from the bristle carrier. Said thickenings may be
produced by thermal melting of the ends. The ends which are melted
are the ends to be over-molded, i.e. said ends are not the ends for
cleaning the teeth. A targeted energy flow is applied to the
cleaning elements at their ends to be over-molded, either
individually or in groups in each case, and reshaped into a
thickening. Generally, this can be carried out by means of various
types of energy flows in the form of mass flows and/or radiation.
For example the ends to be thickened may have a targeted flow of
hot gas applied thereto individually or in groups, in order to be
melted thermally. The corresponding flows of hot gas may be
controlled individually, that is to say independently of one
another, for at least two cleaning elements, in order to achieve an
individual melting and/or reshaping of the ends of the cleaning
elements. Thereby, varying flows of hot gas can be generated with
respect to temperature, gas volume, and/or flow geometry, so as to
be applied differently to the different cleaning elements as a
result. This makes it possible to measure out to each cleaning
element precisely the amount of heat input that is required in
order to produce the desired reshaping.
[0036] The individually controllable flows of hot gas may be
created using separate nozzles that are directed toward the ends of
the cleaning elements to which the hot gas flows are to be applied.
By means of the aforementioned carrier part it is possible to hold
said cleaning elements in a predefined arrangement corresponding to
the desired distribution thereof on the brush head. Thus, the
cleaning elements can have varying flows of hot gas applied to
individually or optionally in groups while they are being held by
the carrier part in the manner in which they are intended to be
cast in the brush head. This reduces additional handling measures,
such as for example grip changes or reinsertion of the cleaning
elements into different carrier parts. Despite the optionally very
dense arrangement, the ends of the cleaning elements can have heat
applied thereto in the desired manner independently of one
another.
[0037] The nozzles in this case are designed such that they can be
moved into various positions relative to one another. For example
the nozzles are designed to be adjustable in a manner such that the
nozzles can be positioned in a grid pattern that corresponds to the
grid pattern of the arrangement of the cleaning elements. The
nozzles can be designed adjustable with respect to their geometry,
such as, for example, the nozzle cross-section or the opening
angle, in order, for example, to be able to apply varying flows of
hot gas to cleaning elements having cross-sections of varying
thicknesses.
[0038] The nozzles may be controlled with respect to their position
and/or geometry, such as the opening angle, according to at least
one property of the respective cleaning elements. Meaning in one
aspect, the nozzles can be adjusted three-dimensionally according
to a property of the respective cleaning elements. For example the
nozzles may be adjusted such that the nozzles can be positioned in
various planes according to the height grid and/or height relief of
the ends of the cleaning elements. I.e. the nozzles can be
positioned in the aforementioned manner at differing heights with
respect to one another, in order to set a uniform distance from the
ends of the cleaning elements, even when similar or identical
cleaning elements are positioned in different planes. Other
properties to which the position of the nozzles may be adjusted are
the softening temperature and/or a cross-sectional geometry of the
cleaning elements.
[0039] The hot-gas device may have a temperature control that
enables the flows of hot gas exiting from the various nozzles to be
controlled at differently hot temperatures in order to be able to
adjust the application of heat individually to the respective
cleaning elements. The temperature of the flows of hot gas in this
case can be adjusted individually for each nozzle according to
different parameters, for example according to a material of the
respective cleaning elements, the softening temperature and/or
according to the cross-sectional surface of the respective cleaning
element. For example, a thicker cleaning element and/or one having
a higher softening temperature can be given a hotter flow of gas
than a thinner cleaning element and/or one having a lower softening
temperature.
[0040] The hot-gas device may have an air volume control that can
individually control the flow of air exiting from the various
nozzles, such that, for example, a stronger flow of air exits from
a first nozzle than from a second nozzle. The flows of air can be
controlled automatically or semi-automatically according to at
least one parameter, for example the softening temperature and/or
the cross-sectional surface of a respective cleaning element.
Alternatively or in addition, individual set nozzle geometry can be
considered, for example in such a way that a greater air flow is
set when the nozzle is set to a larger expansion angle. Various
other parameters may also be considered.
[0041] In addition or alternatively, the ends to be thickened may
have a targeted flow of infrared radiation applied thereto, in
order to be melted thermally. The corresponding amount of infrared
radiation may be controlled individually or in groups, e.g.
independently of one another, for at least two cleaning elements,
in order to achieve an individual melting and/or reshaping of the
ends of the cleaning elements. Thereby, varying amounts of infrared
radiation can be generated with respect to radiation time,
radiation intensity and/or radiation frequency so as to be applied
differently to the different cleaning elements as a result. This
makes it possible to measure out to each cleaning element precisely
the amount of heat input that is required in order to produce the
desired reshaping.
[0042] The individually controllable amounts of infrared radiation
may be created using separate reflectors that are directed toward
the ends of the cleaning elements to which the infrared radiation
is to be applied. By means of the aforementioned carrier part it is
possible to hold said cleaning elements in a predefined arrangement
corresponding to the desired distribution thereof on the brush
head. Thus, the cleaning elements can have varying amounts of
infrared radiation applied to individually or optionally in groups
while they are being held by the carrier part in the manner in
which they are intended to be cast in the brush head. This reduces
additional handling measures, such as for example grip changes or
reinsertion of the cleaning elements into different carrier parts.
Despite the optionally very dense arrangement, the ends of the
cleaning elements can have heat applied thereto in the desired
manner independently of one another.
[0043] The reflectors may be designed such that they can be moved
into various positions relative to one another. For example the
reflectors may be designed to be adjustable in a manner such that
the reflectors can be positioned in a grid pattern that corresponds
to the grid pattern of the arrangement of the cleaning elements.
Alternatively or in addition, the reflectors can be designed
adjustable with respect to their geometry. For example, parabolic
and/or elliptic reflectors can be used having various aperture
and/or diameters, in order, for example, to be able to apply
varying amounts of infrared radiation to cleaning elements having
cross-sections of varying thicknesses.
[0044] The reflectors may be controlled with respect to their
position and/or geometry according to at least one property of the
respective cleaning elements. Meaning in one aspect, the reflectors
can be adjusted three-dimensionally according to a property of the
respective cleaning elements. For example the reflectors may be
adjusted such that the reflectors can be positioned in various
planes according to the height grid and/or height relief of the
ends of the cleaning elements. I.e. the reflectors can be
positioned in the aforementioned manner at differing heights with
respect to one another, in order to set a uniform distance from the
ends of the cleaning elements, even when similar or identical
cleaning elements are positioned in different planes. Other
properties to which the position and/or geometry of the reflectors
may be adjusted are the softening temperature and/or a
cross-sectional geometry of the cleaning elements.
[0045] Alternatively or in addition, the infrared-radiation device
may have a frequency and/or intensity control that enables the
nature and/or amounts of infrared radiation exiting from the
various reflectors to be controlled in order to be able to adjust
the application of heat individually to the respective cleaning
elements. The frequency and/or intensity of the infrared radiation
in this case can be adjusted individually for each reflector
according to different parameters, for example according to a
material of the respective cleaning elements and/or according to
the cross-sectional surface of the respective cleaning element. For
example, a thicker cleaning element and/or one having a higher
softening temperature can be given more infrared radiation being
more energetic than a thinner cleaning element and/or one having a
lower softening temperature.
[0046] The reshaping of the ends of the cleaning elements can be
carried out solely by means of the application of a targeted energy
flow, for example hot gas or infrared radiation, wherein, the
effects of gravity can be utilized. Thereby, the cleaning elements
with their ends to be melted are positioned pointing upward, such
that a melted end section is pressed downward, thus resulting in a
mushroom-shaped or drop-shaped thickening.
[0047] Alternatively or in addition, a punching tool can be used to
create the thickening. Said punching tool may be driven against the
melted ends of the cleaning elements in order to reshape the heated
ends accordingly. The punching tool can have various punching
surfaces, the shapes of which are adapted in each case to one
cleaning element or group of cleaning elements, and which only
reshape individually the one cleaning element or one group of
cleaning elements, respectively. This makes it possible for a
plurality of cleaning elements to be individually reshaped by means
of one punching tool having various punching surfaces. Various
punching surfaces of the punching tool may be adjustable with
respect to one another, in particular to be capable of being
positioned in various planes with respect to one another. This
makes it possible to create a punching tool pad of different
punching surfaces which are positioned raised in relief-like manner
at various heights, in order to enable reshaping of the ends of the
cleaning elements, which ends are positioned at different
heights.
[0048] In addition or alternatively a device is provided for
carrying out the method as described above. Said device comprises
at least a positioning unit for positioning successively or
simultaneously at least two different types of cleaning elements or
at least two distinctive cleaning elements of the same type or a
combination thereof in at least two different mold cavities, an
injection unit capable of injecting at least two different
materials in the at least two different mold cavities and a heating
unit for heating one end of the at least two different types of
cleaning elements or at least two distinctive cleaning elements of
the same type or a combination thereof. The end to be heated is the
end to be over-molded. The heating unit may comprise a hot-gas
device for applying hot gas or an infrared radiation device for
applying infrared radiation to one end of the at least two
different types of cleaning elements or at least two distinctive
cleaning elements of the same type or a combination thereof. In
addition or alternatively a brush head, for example a toothbrush
head is disclosed having bristle tufts comprising at least two
different types of cleaning elements or at least two distinctive
cleaning elements of the same type or a combination thereof being
cast as described above.
[0049] These and other features, which can form the subject matter
of the invention irrespective of how they are summarized in the
claims, optionally in sub-combination, individually or in
combination with one another, will become apparent not only from
the claims but also from the following description and the
drawings, with the aid of which example embodiments are explained
below.
[0050] The toothbrush 1 shown in FIG. 1 comprises a shaft-like
handle 2, which is connected to a brush head 4 via a neck piece 3.
The brush head 4 in this case comprises a bristle carrier 5 joined
to the aforementioned neck piece 3 which supports a bristle field
6, which comprises a multiplicity of bristle tufts 7. Instead of
the bristle tufts 7, or in combination with the bristle tufts 7,
other cleaning elements could be provided, for example in the form
of elastomer strips, sponge elements, or other tooth cleaning
elements. In the embodiment shown, the toothbrush 1 is designed as
a manual toothbrush; however, a motor-driven toothbrush could also
have a correspondingly designed brush head.
[0051] The bristle tufts 7 can usually comprise a multiplicity of
bristles or filaments that are combined to form a tuft 7. The
bristles or filaments in this case are cut to the desired lengths,
the free ends of the tufts optionally being tapered or rounded off
as desired, which can occur on the finished toothbrush 1 or can
also be effected before the bristle tufts 7 are anchored on the
brush head 4.
[0052] FIGS. 2-12 show the fusing of the bristle tufts 7 before
they are fastenedin the bristle carrier 5. According to FIG. 2A,
preconfigured, for example cut-to-length, bristle tufts 7 are first
placed into a carrier part 8 which may form a part of the injection
mold for injection molding the bristle carrier 5 or the brush head
4 later on. As shown in FIG. 2A, the carrier part 8 comprises a
multiplicity of receptacle recesses 9, which are designed in the
form of a through-hole or a blind-hole and which accommodate the
corresponding bristle tufts 7 with an accurately fitting. The
receptacle recesses 9 may be arranged in a grid pattern that
corresponds to the desired positioning of the bristle tufts 7 on
the brush head 4. As shown in FIG. 2B, the bristle tufts 7 with
their ends to be anchored protrude by a certain length beyond the
carrier part 8, such that the aforementioned ends of the bristle
tufts 7 can be positioned in a mold cavity of an injection mold, in
order to be over-molded with plastic therein.
[0053] In order to achieve increased resistance of the bristle
tufts 7 against being pulled from the bristle carrier 5, the ends
of the bristle-tuft 7 to be embedded are first reshaped through
application of heat energy--for example using hot gas 32 or
infrared radiation 33--in order to form thickenings 10, as shown in
FIG. 3.
[0054] In order to produce the thickenings 10, the ends of the
bristle tufts 7 protruding from the carrier part 8 are first melted
through application of hot gas 32 or infrared radiation 33. FIGS.
4A and 4B show the initial state, in which the bristle tufts 7 are
positioned in the carrier part 8, in the arrangement according to
the bristle field 6 to be created, a still non-reshaped bristle
tuft 7 being shown according to FIG. 4B. According to FIG. 4A, the
ends to be melted of the bristle-tufts 7 are arranged in different
planes so that the tuft ends define a three-dimensional
arrangement, cf. FIG. 4a. In the embodiment shown, the ends of
bristle tufts 7 of a center row 35 are positioned higher than the
bristle tufts of rows 36, 37 lying on the outside.
[0055] In order to still be able to achieve an individually adapted
melting despite the three-dimensional distribution and optional
varying cross-sectional surface of the individual bristle tufts 7,
the required amount of heat is supplied individually to each
bristle tuft 7 via variable hot gas input 32 or infrared radiation
33 using a hot-gas device 11 or an infrared-radiation device 34.
Alternatively or in addition identical amounts of hot gas or
infrared radiation can be applied to one or more adjacent bristle
tufts 7. Alternatively or in addition, identical amounts of hot gas
32 or infrared radiation 33 may be applied to rows and/or special
arrangements of bristle tufts 7.
[0056] As shown in FIGS. 5A, 5B, and 6, the hot-gas device 11
comprises a multiplicity of nozzles 12, which are positioned with
respect to one another in a grid-like arrangement which
substantially corresponds to the distribution of the ends of the
bristle tufts in the carrier part 8. In the embodiment shown,
tubular gas outlet channels are provided as the nozzles 12, cf.
FIG. 5a.
[0057] The nozzles 12 may be supported to be three-dimensionally
adjustable; for example, they can be positioned at various heights
in the longitudinal direction of the nozzles 12, as shown in FIG. 6
meaning that different nozzles 12 may be positioned in different
planes with respect to the ends to be heated. The outlet openings
of the nozzles 12 can be placed in a raised, relief-like pattern
that corresponds, in a complementary manner, to the raised,
relief-like arrangement of the tuft ends in the carrier part 8,
such that the distance between the nozzles 12 and the respective
ends of the tufts can be adjusted individually. The distance
between the nozzles 12 and the respective ends of the tufts can be
adjusted individually in all direction in space.
[0058] In the embodiment shown in FIG. 6, consistent distances can
be set between the nozzles 12 and the ends of the tufts 7 to heat
the tufts 7 equally. However, different distances can also be used
taking into consideration various parameters, for example different
bristle materials, tuft cross-sections and geometries.
Alternatively or in addition, different designs of the thickenings
10 may be desired, which may also entail a different setting of the
nozzles 12 to heat the end of the tufts 7 differently.
[0059] The cross-section of the nozzles 12 may be adapted to the
cross-section of the respective bristle tufts 7, for example such
that thicker nozzles 12 are assigned to thicker bristle tufts 7. In
order to achieve greater variability in this case, nozzles 12 may
be optionally used that are adjustable in the cross-section
thereof. If inclined bristle tufts 7 are used, it may be
advantageous to be able to change the adjustment angle of the
nozzles 12.
[0060] Alternatively or in addition to the adjustability of the
nozzles 12, the hot-gas device 11 may also vary the temperature and
the amount or the mass flow of the hot gas flow. To this end, a
temperature-control device and/or regulating device and a mass flow
control and/or regulating device may be provided which can be
designed in such a way that the temperature of the hot gas flows 32
and/or the air volumes and/or the mass flow exiting from each
nozzle 12 can be individually adjusted for each nozzle 12, i.e.
independently of each of the other nozzles 12. In this way, the
desired amount of heat can be supplied individually to each bristle
tuft 7, such that the melting of the ends of the bristles can be
controlled in a targeted manner.
[0061] As a comparison of FIGS. 6 and 7 shows, the ends of the
bristle tufts 7 are melted by the application of hot gas 32 coming
from the nozzles 12 to the extent that drop-shaped thickenings 10
form due to the effects of gravity and surface tension. The bristle
tufts 7 are arranged in an essentially vertical orientation with
the ends to be melted pointing upwards when the hot gas is applied,
cf. FIGS. 6 and 7. Bristle tufts can be angled as discussed
above.
[0062] Generally, it would be possible to successively approach
each bristle tuft 7 to be melted, using a corresponding nozzle 12.
However, all of the bristle tufts 7 can be melted simultaneously
using a multiplicity of nozzles 12, thereby achieving short process
times. Anyway, it is also conceivable for only a part of the
bristle tuft 7 to be melted. According to FIGS. 8A and 8B, it is,
possible to soften all of the bristle tufts 7 in the bristle field
by melting, in order to achieve a corresponding increase in the
pull-out resistance of all of the bristle tufts in a plastic
material.
[0063] As shown in FIGS. 9-11, a mechanical reshaping of the melted
thickenings 10 can be performed. To this end, a punching tool 13 is
used which is moved up against the still-soft, malleable
thickenings 10, in order to shape said thickenings 10 in the
desired manner. As shown in the figures, a flat, disk-shaped
thickening 10 is generated in such a way that a flat punching tool
13 is pressed on the front side against the ends of the tufts.
Differently contoured punching surfaces can also be used to
generate differently contoured thickenings.
[0064] The punching tool 13 may not have a continuous flat punching
surface, but rather a multiplicity of punching surfaces 14, which
may be placed in different planes and/or differently contoured, in
order to generate the desired thickening 10 individually for each
bristle tuft 7 or for one or more adjacent bristle tufts 7. For
example, the punching surfaces 14 may be applied to rows and/or
special arrangements of bristle tufts 7 in order to generate an
identical thickening 10 for several bristle tufts 7. In particular,
the punching surfaces 14 can form a complementary height profile
according to the raised, relief-like height profile of the bristle
tufts 7 positioned in the carrier part 8, in such a way that the
punching surfaces 14 are arranged in various planes in the height
profile, as shown in FIG. 10.
[0065] Owing to a parallel reshaping process of all melted ends of
the bristle tufts 7, same can be shaped in the desired way in a
time-parallel manner, as shown in FIGS. 11A and 11B. In particular,
thin, flat, and/or plate-shaped thickenings 10 can be created, even
when the ends of the bristle tufts 7 are positioned in different
planes and/or provided with different geometries and/or consist of
various materials.
[0066] After forming the thickenings 10 by means of hot gas flows
32, the ends of the bristle tufts 7 can be anchored by over-molding
in a bristle carrier 5; i.e., they are cast into the bristle
carrier 5 during production thereof.
[0067] FIG. 12, in another embodiment, shows instead of a hot gas
device 11 analogous to FIGS. 5A, 5B to 11A, 11B, an infrared
radiation device 34 having reflectors 38 being positioned at the
ends of the bristle tufts 7 protruding from the carrier part 8, to
melt the ends of the bristle tufts 7 to form thickenings 10. A
multiplicity of reflectors 38 having an infrared radiation 33 from
an infrared radiation source 39 are directed onto the protruding
ends of the bristle tufts 7 in order to apply various degrees of
infrared radiation to the various cleaning elements.
[0068] The reflectors 38 in the infrared radiation device 34 are
designed to be adjustable with respect to one another, for example
spatially adjustable. For example, the reflectors 38 may be
designed to be positionable at various heights and/or in various
planes and/or may be designed to be adjustable with respect to the
distances thereof from one another and/or may be supported
three-dimensionally adjustable with respect to one another. A
temperature-control device and/or regulation device may be
provided, independently of one another, for controlling and/or
regulating the infrared radiation 33 exiting from the reflectors
38. The regulation device can be provided also as a control device
or a combined control and regulation device, for controlling and/or
regulating the infrared radiation 33 exiting from the reflectors
38. Suitable regulation parameters may be the radiation time,
radiation intensity and/or radiation frequency.
[0069] After formation of the thickenings 10 using hot gas flows 32
or infrared radiation 33, the ends of the bristle tufts 7 are
mounted by over-molding into the bristle carrier 5 or directly in
the brush head 4; i.e., they are cast into the bristle carrier 5
during production thereof. The embedment can be done with positive
engagement. The injection-molding of the bristle carrier 5 to the
bristle tufts 7 can generally take place in various ways.
[0070] The dimensions and values disclosed herein are not to be
understood as being strictly limited to the exact numerical values
recited. Instead, unless otherwise specified, each such dimension
is intended to mean both the recited value and a functionally
equivalent range surrounding that value. For example, a dimension
disclosed as "40 mm" is intended to mean "about 40 mm"
[0071] Every document cited herein, including any cross referenced
or related patent or application, is hereby incorporated herein by
reference in its entirety unless expressly excluded or otherwise
limited. The citation of any document is not an admission that it
is prior art with respect to any invention disclosed or claimed
herein or that it alone, or in any combination with any other
reference or references, teaches, suggests or discloses any such
invention. Further, to the extent that any meaning or definition of
a term in this document conflicts with any meaning or definition of
the same term in a document incorporated by reference, the meaning
or definition assigned to that term in this document shall
govern.
[0072] While particular embodiments of the present invention have
been illustrated and described, it would be obvious to those
skilled in the art that various other changes and modifications can
be made without departing from the spirit and scope of the
invention. It is therefore intended to cover in the appended claims
all such changes and modifications that are within the scope of
this invention.
* * * * *