METHOD AND DEVICE FOR MANUFACTURING A BRUSH

Description

[0001] The invention relates to a method and a device for manufacturing a brush which has a bristle carrier made of thermoplastic material with at least one anchoring opening into which at least one bristle is inserted and anchored.

[0002] In the manufacture of brushes, especially toothbrushes but also household brushes, two methods have become established in practice: attaching the bristle tufts using an anchor (metal plate or wire loop) or without an anchor. In contrast to using an anchor, the anchorless method involves not folding the bristle tuft and attaching it to the bristle holder at its fold, but rather fixing one end to the bristle holder by gluing or thermally fusing it. A common, established method involves the bristle holder having openings through which the bristle tufts are inserted. The bristle tufts then protrude from the openings at their rear ends and are heated on the back side of the bristle holder.The thermoplastic material of the bristles melts, causing the bristles to merge and forming a thickened structure that makes it impossible to pull individual bristles forward. Typically, the numerous bristle tufts are liquefied on the back side using hot air or a hot stamp, so that the material of the individual bristle tufts merges, creating a layer of liquefied bristle ends. This back side is then covered, usually by overmolding.

[0003] A disadvantage of this solution is that the necessary back cover necessitates a considerable increase in procedural and equipment complexity. It is important to note that, especially with toothbrushes, the transition surfaces between adjacent layers should be as gap-free as possible to avoid hygiene problems.

[0004] The term "bristle carrier" refers to the part of the finished brush that holds the bristle or bristle tufts. The bristle carrier can be the entire brush body—in the case of a toothbrush, the one-piece injection-molded part consisting of the handle, neck, and head—or it can be a pre-fabricated component of the brush body. In the latter case, the bristle carrier is typically a thin plate made of thermoplastic material, which has one or more openings for being filled with one or more bristles or bristle tufts. After the bristles are filled and attached, the plate-like bristle carrier is then inserted into a pre-fabricated brush body, which, for example, has a corresponding recess for the plate-like bristle carrier.Alternatively, and this is the usual case, the plate-like bristle carrier is overmolded, resulting in a brush body consisting of a pre-made bristle carrier and the overmolded remainder.

[0005] Patent application CH 672 579 A5 proposes a method for attaching bristle tufts to a bristle carrier using an anchor plate. This involves folding the bristle tuft, and the anchor plate is positioned within the fold. This plate presses into the wall of the anchoring opening, thus permanently fixing the bristle tuft to the bristle carrier. To ensure optimal closure of the opening at the front and end of the bristle carrier, preventing the accumulation and proliferation of bacteria and spores, a bead is pressed inwards around the anchoring opening. The bristle tuft itself is not secured by this bead formation, but rather by the anchor plate itself. The individual bristle tufts are inserted into the bristle carrier one after the other using a stuffing tool that pushes the folded bristle tuft through a tube.The pipe itself then has a heating element on its end face, which is in contact exclusively with the bead and melts or plasticizes it, then pushes it radially inwards.

[0006] In addition to the aforementioned methods for attaching bristles or bristle tufts to the bristle carrier without anchors, another method has emerged in theory, but it has never gained practical acceptance: the insertion of bristle tufts into a preheated bristle carrier with openings. After the bristle tufts are inserted into the soft bristle carrier, pressure is applied to the front surface of the carrier, from which the bristle tufts protrude, using a press. This compresses the soft material around the edges of the openings, reducing their cross-section. Several concepts related to this method are presented below.

[0007] DE 198 53 030 A1 specifies that bristle tufts have bristles fused together on their back side to form a thickened area. The bristle carrier has openings into which cylindrical extensions of a heating element are inserted before the bristle tufts are pushed in, without touching the edge of the opening. This radiant heat locally heats the inner edge of the openings. The bristle carrier is brought to a temperature that alters its structure, for example, its softening temperature, in the area of ​​the edge. This temperature increase is intended to reduce the cross-section of the opening, so that the bristle tuft must penetrate the wall when pushed in.After the heating element is removed, the bristle tufts are pushed into the openings with their thickened ends. The thickened end has a larger cross-section than the opening, so that it penetrates the softer area of ​​the opening's defining and surrounding edge, i.e., the corresponding wall. Finally, the front of the bristle carrier is deformed with a punch, pressing the carrier material against the bristle tufts and anchoring them in place.

[0008] A similar method is known from US patent 5,224,763, in which the bristle carrier has a bead-like protruding edge around the opening. Here, too, the edge of the opening is heated by inserting a cone-shaped heating element into the opening or by using hot air. The opening itself has a smaller cross-section than the thickened end of the bristle tuft, so that the tuft is fixed in place after being inserted into the wall of the soft opening. The holder for the bristle tufts then compresses the heated circumferential bead, providing additional material to close the opening at the transition to the end face of the bristle carrier.

[0009] From EP 0 355 412 A1 a method is known in which the thickened end of the bristle tuft and / or the edge of the opening in the bristle carrier are heated, wherein the dimensions and the temperatures are chosen such that after the thickened end is inserted, the edge of the opening is forced inwards and thus, similar to a snap connection, encompasses the thickened end and receives it in a form-fitting manner.

[0010] EP 0 472 857 B1 proposes using a heated punch with pins to penetrate a plate-shaped plastic bristle carrier, such that the pins form openings for receiving the bristle tufts. The bristle tufts are then pressed into the imprinted, still-hot openings, and the molten metal rises around the thickening of the bristle tufts. A forming plate can further be pressed against the top of the bristle carrier to shape the molten metal. It is particularly preferred that projections or ridges protrude from the top of the unshaped bristle carrier, forming material that is available to be pressed towards the opening. A very similar solution is proposed in US 4 132 449 A.

[0011] From EP 2 078 472 A1, a method for manufacturing toothbrushes is known in which the bristles are pushed through openings in the bristle holder from the front, so that they protrude from the back. This protruding portion is then melted and reshaped to form a kind of film or plastic plate that is integrally integrated with the bristles. This holds the bristle tufts in place. This film or plastic plate is then covered on the back by gluing or welding on a cover plate.

[0012] In the process according to DE 34 22 623 A1, a bristle carrier, which is plate-shaped and without openings, is welded to bristle tufts made of the same plastic as the bristle carrier. A heating tool is inserted between the unwelded sides of the bristle carrier and the bristle tufts, so that both are melted. Subsequently, the bristle tufts are pressed into the molten material of the bristle carrier.

[0013] The object of the invention is to create a significantly simpler method for manufacturing a brush, which requires less effort in terms of the device, but at the same time ensures a secure anchoring of the bristle or tuft of bristles in the anchoring opening.

[0014] This problem is solved by a method for manufacturing a brush that has a bristle carrier made of thermoplastic material with at least one anchoring opening into which at least one bristle is inserted and anchored. The bristle carrier with its anchoring opening is a pre-molded injection-molded part, making it very easy to manufacture and requiring no machining. The method according to the invention is characterized by the following steps: the at least one bristle is received into a receiving opening of a mold part; the at least one bristle, with its attachment end while still in the receiving opening, is pushed into an anchoring opening of the bristle carrier formed during the manufacturing process (e.g., injection molding) of the bristle carrier, without being fixed therein; the mold part is heated so that the end face of the mold part opposite the bristle carrier is brought to a temperature ofwhich is below the melting temperature of the bristle material and / or the bristle carrier material, in particular below 85% in degrees Celsius of the respective melting temperature of the bristle and / or the bristle carrier material, the tool part is moved relative to the bristle carrier so that the tool part contacts the bristle carrier and heats it up, the tool part exerts a compressive force on the bristle carrier and deforms the bristle carrier at least in the area of ​​the edge surrounding the anchoring opening, reducing the cross-section of the anchoring opening in such a way that the at least one bristle is embedded and anchored in the anchoring opening, and the tool part is moved away relative to the bristle carrier so that the at least one bristle is pulled out of the receiving opening.

[0015] According to a further aspect, the invention relates to a method for manufacturing a brush comprising a bristle carrier with at least one anchoring opening and at least one bristle inserted into the anchoring opening and anchored therein without an anchor, wherein the bristle carrier and the at least one bristle are formed from a thermoplastic material, which may be the same or different, characterized by the following steps: The at least one bristle is received into a receiving opening of a tool part; the at least one bristle, with its attachment end, while still in the receiving opening, is pushed into an anchoring opening of the bristle carrier formed during the manufacture (e.g. injection molding) of the bristle carrier, without being fixed in it;An end face of the tool part opposite the bristle carrier is heated to a predetermined temperature, which lies in a range between ambient temperature and 210 °C, in particular 150 °C. The tool part is moved relative to the bristle carrier so that the tool part contacts the bristle carrier and heats it to the predetermined temperature, but without melting the bristle carrier and the at least one bristle. The bristle carrier is subjected to pressure via the tool part and, at least in the region of the edge surrounding the anchoring opening, is deformed by reducing the cross-section of the anchoring opening such that the at least one bristle is embedded and anchored in the anchoring opening. The tool part is then moved away from the bristle carrier so that the at least one bristle is pulled out of the receiving opening.

[0016] In all embodiments, the thermoplastic material is preferably selected from the group consisting of polyesters, in particular polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), polypropylene (PP), polycarbonate (PC), polyamide (PA), polyvinyl acetate (PVA), polyethylene (PE), acrylonitrile butadiene styrene copolymer (ABS), and styrene acrylonitrile copolymer (SAN). Both homopolymers and copolymers with the aforementioned thermoplastic materials can be used.

[0017] According to the invention, the bristle carrier and the at least one bristle inserted into the tool part should not melt when the tool part contacts the bristle carrier. The predetermined temperature is preferably at most 85% of the melting temperature of the thermoplastic material. This reliably prevents damage to the bristles and / or the bristle carrier.

[0018] The predetermined temperature is particularly preferably in a range between 30 °C and 150 °C, most preferably between 60 °C and 140 °C, and preferably between 90 °C and 130 °C or 100 °C and 115 °C.

[0019] The predetermined temperature is preferably above the glass transition temperature of the thermoplastic. This ensures sufficient deformability of the thermoplastic.

[0020] The method according to the invention differs fundamentally from the prior art because, firstly, it exclusively provides for an anchorless fastening of the bristle, bristle tuft, or bristle tufts. The anchoring opening itself is pre-formed; that is, holes are not pressed into the bristle carrier with heated dies, but rather the anchoring openings are already formed during the injection molding of the bristle carrier. Furthermore, the anchoring opening is not first heated on the inside, thereby softening the inner edge of the opening so that the bristle or bristle tuft is pressed into the soft wall of the receiving opening. Instead, the bristle or bristle tuft(s) is preferably first inserted into the receiving opening, and only then is the bristle carrier heated on its front side opposite the mold part, without melting.The process operates below the melting point of the bristle material and / or the bristle carrier material. Heating is achieved by the tool part itself, in which the bristle or bristle tuft is located, and not by a separate heating tool that would have to be moved away after the bristle or bristle tuft is fed in. Such heating by the tool part itself, in which the bristle or bristle tuft is located, is neither considered nor suggested in the prior art because, in the prior art, the bristle tuft was intended to penetrate the soft, heated wall of the bristle carrier and therefore had to possess high inherent stability in order to transmit the pressing force exerted on the bristle tuft.Only through the pressing force exerted on the back of the bristle tuft and the inherent rigidity of the cold bristle tuft was it possible to press the anchoring end into the softened wall of the bristle carrier. Furthermore, heating occurs through contact with the bristle carrier by the heating tool component itself, and not, as is predominantly the case in the prior art, through contactless heating. This allows for faster energy transfer and enables the device to be manufactured with fewer parts.

[0021] The bristle carrier is heated to a temperature below its melting point during the entire forming process, preferably to a temperature significantly below the melting point, for example, at least 15% below the respective melting point (calculated in °C) and preferably a maximum of 15% above the glass transition temperature (calculated in °K) for a bristle carrier material with a glass transition temperature of 300 K or greater. For a bristle material with a glass transition temperature of less than 300 K, the temperature to which the bristle carrier is heated during the entire forming process is a maximum of 50% above the glass transition temperature (calculated in °K). Preferably, the bristle carrier is heated to a temperature above the glass transition temperature.

[0022] The invention and its advantageous variants described above and below provide in particular for the use of polypropylene, some groups of which have a glass transition temperature of less than 300 K and others of which have a glass transition temperature above 300 K, as a bristle carrier material. Other preferred bristle carrier materials are PET, PBT, PA, ABS, SAN, and PC. These bristle carrier materials all have glass transition temperatures above 300 K.

[0023] The glass transition temperature can be determined, for example, by dynamic mechanical thermal analysis (DMTA). For semi-crystalline thermoplastics, the melting temperature is considered to be the upper end of the melting range. This can be determined, for example, by differential scanning calorimetry (DSC). For amorphous thermoplastics, the transition to the flow or processing range is considered the melting temperature.

[0024] To ensure a relatively short cycle time when manufacturing bristle carriers, one embodiment of the invention provides that the tooling component is heated before it contacts the bristle carrier. This, of course, has the disadvantage that the bristle or bristle tuft itself is also heated, which was undesirable in the prior art, as the bristle tuft should press into the soft wall. According to the invention, the tooling component can already be heated to its predetermined maximum operating temperature before it contacts the bristle carrier.

[0025] The invention provides, among other things, in one embodiment, that the melting temperature of the plastic of the bristle carrier is below the melting temperature of the bristle(s). However, there are also brushes in which the bristle carrier material is the same as the bristle material, for example, polypropylene and PA.

[0026] As previously explained, the bristle carrier should only be heated after at least one bristle has been inserted through the tool part, preferably solely by contact. Of course, if a bristle carrier comes into close proximity with a warm or hot tool part, a minimal temperature increase may occur, but this increase is absolutely negligible and takes place only on the immediate surface.

[0027] However, if the feed movement takes a very long time, an alternative approach is conceivable: the tool part could heat the bristle carrier in the area of ​​the contact surface with the tool to a temperature below the melting point of the bristle carrier material and, preferably, greater than or equal to the glass transition temperature of the bristle carrier material during the tool part's feed movement. Alternatively or additionally, the bristle carrier could also be heated to the aforementioned temperature when the tool part makes contact with it.

[0028] According to one embodiment of the invention, the heating of the bristle carrier to the predetermined and previously mentioned temperature or temperature range should extend 0.25 to 0.5 mm below the surface of the bristle carrier facing the tool part (front side) until the deformation process is complete. Since the tool part presses against the bristle carrier for an extended period and thereby heats it, the thermal energy also penetrates deeper into the interior of the bristle carrier. Therefore, the bristle carrier does not need to be heated to a depth upon initial contact with the tool part; it is sufficient to achieve this heating during the feed movement and the contact time.

[0029] In the first phase of the feed movement, the tool component can heat the bristle carrier, at least in the area of ​​the edge surrounding the anchoring opening, but preferably in the entire contact area, to a temperature above a limiting temperature that corresponds to 60% in °C, and in particular 80%, of the glass transition temperature of the bristle carrier material, when using a bristle carrier material with a glass transition temperature of 300 K or greater. This applies in particular to bristle carrier materials such as polypropylene variants with a glass transition temperature of 300 K or greater, PET, PBT, PA, ABS, SAN, and PC. Alternatively, the limiting temperature is the ambient temperature when using a bristle carrier material with a glass transition temperature of less than 300 K, which is particularly the case when using polypropylene variants with such low glass transition temperatures.The heating takes place before the tool part deforms the edge in a second phase of the feed movement and the edge presses against at least one bristle.

[0030] The bristle carrier material can be heated to a temperature in a range between the glass transition temperature and below approximately 85% of the melting temperature of the thermoplastic, measured in °C. Depending on the thermoplastic material used, this temperature is preferably in a range between 30 °C and 210 °C, particularly preferably between 60 °C and 140 °C, and more preferably between 90 °C and 130 °C or 100 °C and 115 °C.

[0031] As tests have shown, the bristle or bristle tuft should first be inserted into the receiving opening before the tool part contacts the bristle carrier, in particular before the bristle carrier has been heated, at least in the area of ​​the edge surrounding the anchoring opening (preferably in the entire contact area), to a temperature above a limit temperature that is 40% in °C, in particular 20% in °C below the glass transition temperature of the bristle carrier material when working with a bristle carrier material with a glass transition temperature of 300 K or greater (this applies in particular to bristle carrier materials such as polypropylene variants with a glass transition temperature of 300 K or greater, PET, PBT, PA, ABS, SAN and PC), or which corresponds to the ambient temperature when working with a bristle carrier material whose glass transition temperature is less than 300 K.This applies particularly to polypropylene variants with such low glass transition temperatures. The edge of the anchoring opening is at least the outer edge on the front of the bristle carrier.

[0032] Another embodiment of the invention provides that the at least one bristle or tuft of bristles is first inserted into the receiving opening before the edge of the anchoring opening is heated to a temperature at least 30 °C above the ambient temperature, and in particular before the edge of the anchoring opening inside the anchoring opening is heated above the ambient temperature by the tool part. This means that, in the latter embodiment, the edge inside the opening is not noticeably heated, in contrast to the prior art, where heated pins were intended to penetrate the opening to heat the inner edge of the opening, i.e., the wall defining the opening, down to the bottom of the hole.

[0033] The deformation should be such that the edge of the bristle holder, at the transition to the front or end face of the bristle holder, presses against the outer bristles of the attached bristle tuft along its entire circumference, thus compacting the bristle tuft. Naturally, the type and extent of this compaction depend on the cross-section of the bristle tuft. For example, in toothbrushes, the cross-section of the anchoring opening is reduced by a maximum of 0.3 mm, preferably by a maximum of 0.15 mm.

[0034] Preferably, the lack of heating of the opening wall also applies to the other embodiments. This means that, optionally, only the edge in the area of ​​the front, i.e., at the transition from the front to the anchoring opening, is brought to the specified limit temperatures or temperatures; however, the ambient temperature in the opening itself is essentially maintained as long as the tool part does not contact the bristle carrier.

[0035] A preferred embodiment of the invention provides that the tool part is heated across its entire contact area with the bristle carrier, and not only in the localized or linear area around the edge of the anchoring opening. This has the advantage that the tool part has access to the entire contact area, and thus the entire adjacent material area of ​​the tool part, to move and deform this material area by means of the high applied pressure. Furthermore, it is advantageous if the tool part even contacts the entire end face of the bristle carrier facing the tool part, i.e., its front surface, or at least 70% of the front surface area, and applies pressure to it. In the prior art, protruding ridges on the manufactured bristle carrier created a kind of collar, which constituted the only heated and deformed material.The present invention differs significantly from this, however, in that precisely those sections of the bristle carrier are heated and reshaped that are located away from the front edge of the anchoring openings.

[0036] The back of the bristle carrier should not be heated by the tool during anchoring, so that only the front side, facing the tool, is heated and reshaped, while the back side forms a plate-like, stable structure that could be described as the base of the bristle carrier. This part of the bristle carrier is therefore not reshaped or altered in form during pressure application.

[0037] The tool component can, at least for the entire time it exerts pressure on the bristle carrier, also heat the end face of the bristle carrier. Therefore, the invention does not involve a brief pre-heating of the bristle carrier followed by the rapid movement of the bristle tufts into the heated material sections of the bristle carrier, as is the case in the prior art with pre-heated bristle carriers into which bristle tufts are then inserted.

[0038] The plastics used in the present invention are, for example, copolyesters, in particular Eastar™< BR003 (with a melting temperature range of 230 to 280 °C), polypropylenes, in particular a homopolymer such as PPH5042 with a melting temperature of 165 °C, polycarbonate, polyamide, polyvinyl acetate, or polyethylene. If these materials have a glass transition temperature above the ambient temperature, here 300 K, energy should be introduced into the bristle carrier via the tooling component. This is also advantageous for materials whose glass transition temperature is below the ambient temperature.

[0039] Advantageously, bristle carrier materials are heated to the following temperatures in the inventive method and by the inventive device explained below: Bristle carrier material Melting point [°C] Glass transition temperature [°C] Process temperature [°C] Polypropylen 160°-170° -10° - 0° < 136° PET 260° 70° < 120° PBT 220° 47° < 95° PA 200° - 260° 50 - 60° < 98° ABS 220° - 250° 95° < 150° PC 220° - 230° 148° < 210° SAN 200° 108° < 165°

[0040] The invention provides, in particular for PET, for heating the front of the bristle carrier in a range of 75-95 °C, especially 80-90 °C, and for PP from 115 to 125 °C, especially 110-120 °C.

[0041] In particular, PP with a Melt Flow Index (MFI) of 6-35, preferably of 10-15, is used.

[0042] In its preferred embodiment, the method according to the invention provides not just one bristle inserted into a single receiving opening, but rather several anchoring openings and several receiving openings in the bristle carrier or in the tool part. The receiving openings are aligned with the corresponding anchoring openings. Bristle tufts are inserted into the receiving openings and then pushed into the anchoring openings, preferably simultaneously. The tool part simultaneously heats at least the edges of the anchoring openings, preferably the entire contact surface, so that the entire area between the anchoring openings is heated. By applying pressure to the front of the bristle carrier, the anchoring openings are closed simultaneously, thereby anchoring the bristle tufts at the same time.

[0043] Preferably, the contact area between the tool part and the bristle carrier on the tool part is flat, as is the front of the bristle carrier, which faces the tool part.

[0044] The feed movement of the tool part relative to the bristle carrier can be pressure- and time-controlled and / or pressure- and distance-controlled.

[0045] Alternatively, the device can simply be brought to a stop by, for example, using an electric motor (e.g., via a spindle drive), whereby the current or power consumption of the electric motor is detected and, upon reaching a predetermined limit, it is assumed that the device is in the closed position, in which preferably the holder and the tool part are in contact. From this point on, the so-called holding time could then begin.

[0046] The term "movement or delivery movement of the tool part relative to the bristle carrier" means that one or both parts are moved relative to each other.

[0047] Another embodiment of the invention provides that, from the moment of contact with the bristle carrier, the tool part exerts a preferably constant pressure force on the bristle carrier for a predetermined period. This optional method is particularly easy to implement, as a pressure force is simply applied and maintained on the bristle carrier for a certain time, essentially as an engagement period, before the tool part and bristle carrier are subsequently separated. As with the other embodiments of the invention, no further process steps are required to anchor the bristle or bristle tuft(s) in the bristle carrier.

[0048] The feed movement and / or the applied pressure from the tool part relative to or on the bristle carrier can be non-linear over time from the point of contact between the tool part and the bristle carrier until the maximum feed path is reached. This allows, for example, a longer or shorter initial temperature exposure time, followed by the application of a different pressure to further and permanently deform the bristle carrier material.

[0049] In contrast to the previously mentioned prior art, the attachment end of at least one bristle or of the entire bristle tuft(s) can be smaller than the cross-section of the anchoring opening(s) when inserted into the associated anchoring opening(s), naturally before the opening is deformed and before the bristle carrier is heated. This means that the bristle tuft is not pressed into the side wall of the anchoring opening, as proposed in the prior art. The attachment end is also not pressed into the bottom of the anchoring opening, because the bottom is not heated, or not heated sufficiently, to be soft. Furthermore, no axial force is exerted on the bristles beyond the force necessary to push the bristles out of the receiving opening.

[0050] Similar to the anchorless fastening method used in practice, at least one bristle or the entire bristle tuft can be given a thickened fastening end by thermally forming the bristle material above its melting point. When using a bristle tuft, the bristles within the tuft are joined together by thermal forming. However, adjacent bristle tufts are not joined together; instead, each bristle tuft has its own thickened fastening end, which is inserted into the anchoring opening.

[0051] The invention allows not only bristle tufts to be attached to the anchoring opening by reshaping the edge of the opening, but also prefabricated so-called elastomeric cleaning elements (e.g., made of thermoplastic materials) that are several times thicker than normal bristle filaments. These cleaning elements serve to improve cleaning and, in the case of a toothbrush, to massage the gums. Furthermore, these cleaning elements do not necessarily have to be pin-shaped, but can have any cross-section, in particular elongated, arc-shaped, cruciform, or round (circular or oval) shapes, as well as corresponding ring shapes with central openings.

[0052] At least one anchoring opening can be filled with a single, prefabricated bristle made of an elastomeric material, in particular thermoplastic elastomer (TPE). This single bristle is anchored in the anchoring opening by deforming the bristle carrier.

[0053] Preferably, the single, pre-fabricated bristle has a maximum wall thickness, measured in cross-section, of greater than 0.6 mm, and in particular greater than 0.9 mm. For example, in the case of a rectangular cross-sectional shape, the maximum wall thickness is measured in the longitudinal direction.

[0054] Optionally, the single, pre-fabricated bristle can have a thickened attachment end, which is inserted into the anchoring opening and gripped by the deformed edge of the bristle carrier's anchoring opening. This thickened attachment end is created during the manufacturing of the single bristle and not by pressing and elastically deforming the bristle through the deformation of the anchoring opening's edge. Alternatively, it would be possible to work without a thickened attachment end if the bristle is thick enough and the edge is pressed into the elastic bristle, so that the attachment end then thickens due to the displaced material.

[0055] The thickened attachment end, for example, has the shape of a flat cylinder and / or the single, pre-formed bristle is a multi-component injection-molded part. In this context, the thickened attachment end can be made of a different, preferably harder, material, such as polypropylene, than at least the outer surface of the single, pre-formed bristle outside the anchoring opening. Preferably, the attachment end is even harder than the entire rest of the single, pre-formed bristle. The harder attachment end improves the bristle's fit in the anchoring opening.

[0056] Typically, several anchoring openings are provided in the bristle carrier, with at least one, preferably several, anchoring openings being equipped only with the single, pre-formed bristle(s). At least one other, preferably the remaining, anchoring openings, however, are equipped with pre-formed bristle tufts, so that the brush has a hybrid form of conventional bristle tufts and thicker, elastomeric cleaning elements.

[0057] Viewed from the side, the individual bristle extends with its free end at least to the free end of the bristle tuft, meaning it is not shorter than the bristle tufts. It can be advantageous if the elastomeric cleaning elements, i.e., the individual bristles, are even longer than the bristle tufts and extend beyond their ends at the front. Of course, the elastomeric cleaning elements can also be shorter than the bristle tufts.

[0058] Crucial to the present process, and a significant difference from the prior art, is the relatively long contact time of the tool component on the bristle carrier, during which pressure is exerted and the bristle carrier is additionally heated. The contact time is at least 5 seconds, in particular at least 6 seconds, and a maximum of 15 seconds, in particular a maximum of 10 seconds. During this long contact time, the pressure can remain constant and / or the bristle carrier can be continuously heated. Maintaining constant pressure is relatively easy to achieve.

[0059] The anchoring opening can be a blind hole, in particular with a maximum depth of 4 mm, and furthermore in particular with a maximum depth of 2.7 mm.

[0060] By deforming the bristle carrier in the area of ​​the front, the thickness of the bristle carrier is reduced by the method according to the invention.

[0061] The anchoring opening is only reshaped and narrowed to a maximum depth of 85%, in particular a maximum of 70%, preferably even a maximum of 60% of its total depth; that is, it is not narrowed in the area of ​​the bottom of the blind hole.

[0062] Another significant difference from the prior art lies in the applied pressure, which is considerably higher than that in previously proposed methods. Specifically, the tool component exerts a pressure of at least 200 bar, and in particular at least 400 bar, on the bristle carrier.

[0063] At least one anchoring opening, preferably all anchoring openings, have no protruding collar in the area of ​​the anchoring opening's mouth before the bristle carrier is acted upon by the tool part; rather, these bristle carriers are flat on their front side facing the tool part, at least in the contact area with the tool part. The enormous pressure of 200 bar and more ensures that the entire surface or contact area is deformed and, with the exception of the angled anchoring opening explained below, no protruding collar is necessary as a material accumulation.

[0064] If the anchoring opening has an internal edge section that runs obliquely to its front face opposite the tool part, an additional accumulation of material may be necessary in this area. In this case, before the tool part impacts the bristle carrier, the end face of the bristle carrier will have a projection extending towards the tool part in the area of ​​the oblique edge section. Otherwise, it is advantageous for the front face of the bristle carrier to be completely flat.

[0065] A magazine is used as a tool component, which is loaded with at least one bristle or at least one tuft of bristles. If several bristles or tufts of bristles are to be attached to the bristle carrier, all bristles or tufts of bristles are housed in the same magazine and are inserted simultaneously after loading.

[0066] After being loaded, the attachment end(s) of the bristles or bristle tufts protrude from the magazine and are heated at this point without leaving the magazine. The thickening then forms at the attachment end that is freely protruding from the magazine. The magazine is therefore not only a stamping tool, but also a transport tool that is advanced laterally from a loading station to the bristle carrier and then pressed against it.

[0067] As already mentioned, the tool part has, for example, a flat end face facing the bristle carrier (at least in the contact area with the bristle carrier) and / or a geometry that cannot protrude into the anchoring opening, i.e., without pin-like projections or the like, as proposed in the prior art.

[0068] As it turns out, the position of the so-called parting line between the holder and the tool part, where they abut each other, is important relative to the bristle carrier. It is therefore advantageous if the cavity formed to receive the bristle carrier is not only located in the holder but also partially in the tool part. However, relative to the thickness of the bristle carrier, the majority of the cavity is formed by a recess in the holder. The parting line should preferably be located close to or immediately adjacent to a rounded transition between the side surface and the front of the bristle carrier, i.e., outside the rounded transition. This ensures that this rounded transition is not provided with any step or burr created by extruded material from the bristle carrier.

[0069] By applying pressure and heat, or pressure alone, the overall thickness of the bristle carrier is permanently reduced, meaning not just partially, but completely. The end face of the tool component opposite the bristle carrier is heated to a temperature of at most 140 °C, and in particular at most 130 °C. For example, polypropylene, PET, ABS, or SAN are used as materials for the bristle carrier.

[0070] When using PET as the bristle carrier material, it has been found that the front of the bristle carrier should be heated to 75-95 °C, particularly 80-90 °C, during forming, and when using PP (for example with a Melt-Flow Index (MFI)) of 6-35, preferably 10-15, to 105-125 °C, particularly 110-120 °C.

[0071] As briefly mentioned earlier, at least one protruding, elastic cleaning element made of an elastomer, particularly TPE, can be injection-molded onto the bristle carrier before or after the attachment of at least one bristle and attached to the bristle carrier. The cleaning element is positioned at the edge of the bristle carrier and / or inwards of the edge between bristles or bristle tufts. Consequently, hybrid forms of cleaning elements within the same brush are conceivable. Injection-molded cleaning elements, bristle tufts attached to the bristle carrier by deforming the edge of the anchoring opening, and individual bristles in the form of prefabricated elastomeric cleaning elements, also attached to the bristle carrier by deforming the edge of the anchoring opening, can be attached to the bristle carrier in any combination. Furthermore, the brush body can be designed as a multi-component injection-molded part.

[0072] The bristles may also be pre-pointed, either chemically or mechanically pre-pointed, or pre-rounded.

[0073] Several bristle tufts can be anchored in the same bristle carrier, with at least one tuft consisting of bristles made of a different material with a different melting point than the bristles of at least one other tuft. The bristle tufts made of different materials are heated to varying degrees to fuse the bristles of each tuft together, forming a thickened attachment end. This can be achieved in various ways: the distance between the end of the bristle tuft facing the heating element and the heating element is adjusted depending on the bristle material; and / or the heating element is heated to different temperatures depending on the bristle material; and / or different heating elements, heated to different temperatures and tailored to the respective bristle material, are used.

[0074] For example, the bristle tufts are pushed out of the magazine to varying distances. Those tufts made of a more easily melting material remain closer to the magazine than the others, so that the tufts extended further come closer to the heating element and are therefore heated more intensely. Alternatively, the bristle tufts can be processed sequentially by pushing the tufts with different bristle materials out of the magazine one after the other, using their attachment ends, to bring them closer to the heating element. Either the heating element is then heated to two suitable, different temperatures, or heating elements of different temperatures are used for their respective assigned bristle tufts.

[0075] For example, in a brush with nylon and PBT bristles, the nylon bristles are heated first, followed by the PBT bristles.

[0076] The aforementioned advantageous variants can expressly be combined with each other as desired.

[0077] The object of the invention is also achieved by a device for producing a brush having at least one bristle or at least one tuft of bristles, preferably several tufts of bristles, which has a bristle carrier with at least one anchoring opening for the at least one bristle or the at least one tuft of bristles, in particular for carrying out the method of the invention, wherein the device has a holder for the bristle carrier and a tool part (for example designed as a press die) with at least one receiving opening for the at least one bristle or the at least one tuft of bristles, wherein the receiving opening opens on the end face of the tool part facing the bristle carrier, and wherein the tool part has a heating element that heats at least sections of the end face, which is designed and controlled in such a way that the end face is heated to a temperature of at most 140 °C, in particular at most 130 °C.In particular, polypropylene, PET, ABS or SAN are used as materials for the bristle carrier.

[0078] In the device according to the invention, a tool part, which serves as a temporary carrier for the bristle or bristle tuft(s), is used as a press punch and simultaneously as a transport means. A heater on the end face of the tool part is designed and controlled such that the end face is heated to a maximum temperature of 140 °C, in particular a maximum of 130 °C, when it is moved against the bristle carrier. A device that could theoretically operate at higher temperatures, but whose control system limits the temperature accordingly, naturally also falls under the definition of the device.

[0079] As previously explained in connection with the method, the feed movement of the tool part relative to a holder of the bristle carrier can be realized by moving the holder and / or the tool part, whereby the feed movement can be pressure- and time-controlled and / or pressure- and displacement-controlled or only time-controlled or only displacement-controlled.

[0080] The device according to the invention can apply a pressure of at least 200 bar, in particular at least 400 bar, to the bristle carrier, i.e. in the direction of the holder.

[0081] The heating capability of the tool part should be implemented across the entire contact area with the bristle carrier, or even across the entire area of ​​the end face of the tool part that faces the holder and thus the bristle carrier inserted into the holder.

[0082] As further explained in connection with the method according to the invention, the tool part is, for example, a magazine which is loaded with at least one bristle or at least one tuft of bristles in a loading station of the device. After loading, the at least one bristle or at least one tuft of bristles (the term "at least one bristle" generally includes, for the purposes of this entire description and the claims, one or more tufts of bristles) protrudes from the magazine with its attachment end. In a melting station located downstream of the loading station, the attachment end(s) are heated, causing a thickening to form. When using one or more tufts of bristles, the bristles of the respective tuft are joined together by thermal forming. In particular, a mushroom-shaped, dome-shaped, or spherical thickening is formed.

[0083] In general, with the device according to the invention, either the magazine can be moved and the stations remain stationary, or the magazine can remain stationary and stuffing tools, heating devices, or holders can be moved to the magazine. These tools or holders can, for example, be arranged on a rotating carousel that successively moves through the stationary magazines. The device according to the invention has a control system that regulates the feed movement of the tool part relative to the bristle carrier as well as the heating process of the tool part such that the tool part is heated before it contacts the bristle carrier. This means that the tool part is already warm before the feed movement of the tool part towards the holder. The maximum operating temperature may, but does not necessarily, have been reached at this stage.The bristle carrier is only heated after at least one bristle has been inserted through the tool part, which is achieved by the protrusion of the thickened end relative to the magazine and the distance of the front face of the magazine to the corresponding contact surface on the bristle carrier.

[0084] The device according to the invention is designed in particular such that the tool part is permanently heated to the desired temperature necessary for heating the front surface of the bristle carrier for the forming process. This means that the tool part is already warm and at this desired temperature when the at least one bristle or bristle tuft(s) are inserted into the receiving opening(s). If the tool part also receives the at least one bristle / bristle tuft during the melting of the bristle ends to form the thickened attachment end, care must be taken to ensure that the temperature of the tool part and / or the dwell time of the at least one bristle / bristle tuft in the receiving opening does not lead to deformation of the bristle or bristles of a bristle tuft.

[0085] The control unit can heat the tool part to such a temperature and control the feed of the tool part to the bristle carrier such that the tool part brings the bristle carrier in the area of ​​the contact surface with the tool part to a temperature during the feed movement of the tool part to the bristle carrier and / or upon contact of the bristle carrier that is below the melting temperature of the material of the bristle carrier and, preferably, greater than or equal to the glass transition temperature of the material of the bristle carrier, in particular wherein the control unit is programmed such that, for a bristle carrier material with a glass transition temperature of greater than or equal to 300° K, it sets the temperature of the tool part to a maximum of 15% above the glass transition temperature calculated in ° K, and for a bristle carrier material with a glass transition temperature of less than 300° K, it sets it to a maximum of 50% above the glass transition temperature in ° K.

[0086] Naturally, brush bodies or bristle carriers manufactured using standard one- or multi-component injection molding processes can be used in the inventive method or device. For example, handles, or more generally, brush bodies or bristle carriers, can be used that are typically found in toothbrushes traditionally filled with (metal) anchor bristles. However, these handles / brush bodies / bristle carriers usually have deeper anchoring openings than are necessary in the inventive method.

[0087] Multi-component handles, brush bodies, or bristle carriers have been used for years in anchor technology, where elastomeric structures are injection-molded onto the brush head between the anchoring openings and / or the edge of the brush head. Elastomeric tongue cleaners, for example, can also be attached and injection-molded onto the back of the brush head. All these possibilities also apply to the inventive method and device.

[0088] In the anchor technique, these elastomeric structures are applied to the front or back before the bristles are added. Only in exceptional cases is the elastomeric structure applied after the bristles, which is not common practice. Most often, these elastomeric structures are injection-molded onto a stiffer support structure using a multi-component injection mold. Such multi-component molds for toothbrush bodies are very common.

[0089] The handles, brush bodies / bristle carriers, which are supplied to the inventive method and / or device, can be easily injection-molded using all currently known brush body injection molding techniques and tools. The anchoring openings are pre-molded using forming pins, which can be round or any desired cross-sectional shape and which project into the injection cavity. These pins can then be withdrawn from the cavities after sufficient cooling and / or curing of the injected plastic, e.g., using slides, before the injection-molded part is completely demolded. The forming pins can be arranged parallel and / or at an angle to each other in order to create parallel and / or angled anchoring openings in the injection-molded part.In the inventive method and apparatus, pins typically penetrate the injection cavities somewhat less deeply when injection molding such parts than when injection molding brush bodies or bristle carriers intended to be filled using the anchor technique. Consequently, the anchoring openings in the injection lengths are somewhat shallower. Because these openings are shallower, the overall head thickness of the brushes produced using the inventive method and apparatus can be significantly reduced compared to brush heads filled using the anchor technique. This offers a clinical advantage in the manufacture of toothbrushes.

[0090] The inventive method and apparatus offer particular advantages when using clear materials for the bristle carrier or brush body. Such materials are typically PET, copolyester, SAN, ABS, etc. These materials, like polypropylene bristle carriers / brush bodies / handles, can also have pre-molded anchoring openings and / or be provided with elastomers (e.g., TPE, TPU) using a multi-component process. After the bristle carriers / brush bodies / handles have been injection-molded using a multi-component process, they can be further processed as described above and subsequently using the apparatus, as provided for in the invention.

[0091] Upstream of the station with the holder and the tool component, which acts, for example, as a press ram, an injection molding station for producing the tuft carrier can be provided. This injection molding station includes an injection mold half with at least one extension projecting into an injection cavity. This extension is either rigidly attached to the injection mold half or is an integral part of it. This renders the active slides previously used in injection mold halves partially or even completely unnecessary. Each extension creates an anchoring opening designed as a blind hole. Slides are not only complex to manufacture but also require extensive maintenance and repair.Because the bristle or bristle tuft is not fixed in the bristle carrier with an anchor in the device according to the invention, which requires a minimum depth for the anchoring opening, anchoring openings with a shallower depth are perfectly sufficient for fixing the bristle or bristle tuft.

[0092] Furthermore, it is expressly pointed out that the advantages and features previously mentioned in connection with the inventive method are also applicable to the inventive device, either individually or in combination, in accordance with the inventive method.

[0093] Furthermore, it should be emphasized that the method and apparatus according to the invention can be used with any type of brush, not just toothbrushes. For example, the method and apparatus can also be used for household brushes, scrub brushes, household brooms or brooms of any kind, dish brushes, toilet brushes, hairbrushes, vacuum cleaner brushes, hand washing brushes, and paintbrushes of any kind, for example, for painting, varnishing, or nail polish, facial brushes (just like toothbrushes, manual or electric brushes). The details and variations described in the following drawings are therefore also applicable to all these brushes.

[0094] Further features and advantages of the invention will become apparent from the following description and from the following drawings, to which reference is made.

[0095] The drawings show: Figure 1a to 1gvarious successive steps of the inventive method in perspective top view and perspective bottom view, which also shows the inventive device, Figure 2 an enlarged view of the perspective bottom view of the anchoring station in Figure 1e , Figure 3 a cross-sectional view through the in Figures 1e and 1f Anchoring station shown before the magazine and bristle carrier move towards each other, Figure 4 a corresponding view of the station Figure 3 upon initial contact between the magazine and the bristle carrier, Figures 5 and 5A corresponding views of the anchoring station after Figure 3 after the end of the delivery movement and after the end of the exposure time, immediately before the station is separated and opened, Figure 6 a sectional view through an alternative assembly station, Figure 7 a cross-sectional view through the anchoring station according to Figure 3, in which slanted bristle tufts are processed, Figure 8 a sectional view through an alternative bristle carrier used in the invention, Figure 9 a front view of a bristle carrier produced according to the present invention, Figure 10 a sectional view through an injection mold used to produce the bristle carrier Figure 9 is injected, Figure 11 a cross-sectional view through a bristle carrier during the insertion of bristle tufts and / or individual elastomeric bristles, Figure 12 Variants of singular, prefabricated bristles used in the invention, Figure 13 Variants of the method and device according to the invention, Figure 14 an enlarged sectional view through a variant of the device according to the invention, here the anchoring station, with the holder according to the invention, and Figure 15an enlarged sectional view through yet another variant of the device according to the invention, here the anchoring station, with the holder according to the invention when used for a bristle carrier provided with an elastomer.

[0096] In Figure 1Figure 1 shows a device for manufacturing brushes, such as toothbrushes. A toothbrush, as is well known, has a brush head with bristle tufts projecting from the front, a neck, and a handle. These three sections can be joined together in one piece, forming the so-called brush body. The brush head can either be filled directly with bristles or it can be made in two parts: a plate-like bristle carrier, which, after injection molding, already has pre-made, blind-hole-like anchoring openings. This plate-like bristle carrier is then joined to the rest of the head, either by welding, gluing, or overmolding. Alternatively, the brush head can be made in one piece, so that it itself forms the bristle carrier.

[0097] Such a design is in Figure 1As shown, the brush head simultaneously forms the bristle carrier 10. In this illustration, the bristle carrier 10 is also the brush body, as it encompasses the handle, neck, and head of the brush. The bristle carrier 10 is a prefabricated, injection-molded part. Figure 2 Figure 1 shows that the bristle carrier 10 has numerous pre-formed openings 12 on its underside, created during injection molding, into which bristle tufts are inserted and anchored. The following description, however, is identically transferable and legible for plate-like bristle carriers 10.

[0098] The in Figure 1 The device shown comprises several stations, namely a loading station 14, which is located in the Figures 1a and 1b The image shows a melting station 16, which is located in Figure 1c shown, as well as an anchoring station 18 for the bristle tufts, which are in the Figures 1e and 1f is shown.

[0099] All stations are traversed by a magazine 20, also called a tool part, which transports tufts of bristles through the individual stations.

[0100] Although in Figure 1 As shown in the illustration of a magazine 20 with receiving openings for a brush (shown in more detail later), in practice the magazines 20 are preferably large enough to contain several adjacent groups of receiving openings for multiple brushes. Multiple rows of groups of receiving openings for multiple brushes are also possible.

[0101] Magazine 20, for example, is a plate-shaped part with a constant thickness, which, according to Figure 1 The magazine has an upper, flat front face 22. Alternatively, the magazine, which is essentially plate-shaped, has a recess 200 on its flat front face 22 with a bottom 202, which can also be flat, as shown in Figure 14is shown to form part of a cavity for receiving the bristle carrier 10.

[0102] Since the magazine passes through several stations and is subsequently used for the production of further brushes, the device incorporates a magazine circulation system, whereby numerous identically designed magazines 20 are indexed sequentially through the individual stations. The magazine 20 thus serves as a transport means for bristle tufts 24 through the device. Alternatively, the magazine can be stationary, and the individual stations are indexed around the magazine, for example, on a carousel. In this case, several stationary magazines can be processed simultaneously, or more precisely, the bristle tufts arranged in the magazines can be processed.

[0103] The magazine 20 has numerous receiving openings 26, which have a hole pattern that corresponds to the hole pattern of the bristle carrier 10.

[0104] Each bristle tuft 24 consists of several bristles that are separated from a bristle supply and, as Figure 1a The figure shows that the bristle tufts can be inserted into the magazine 20, for example via pins, as will be explained later. The individual bristle tufts 24 can be transported via tubes using compressed air or vacuum.

[0105] The bristles are made of a thermoplastic material, in particular PA, PBT, polyester, copolyester, or polypropylene; however, they can also be made of elastomers. Furthermore, it is also possible to use co-extruded bristles, for example, with a PA core coated with an elastomer. As will be shown later with regard to… Figures 11 and 12As will be explained later, it is not absolutely necessary that only bristle tufts 24 be used and embedded in the anchoring opening; rather, a single, prefabricated bristle, for example in the form of an elastomeric cleaning element, can also be inserted and fixed in its anchoring opening according to the aforementioned and subsequently described procedure. Such cleaning elements are injection-molded or foamed separately and are softer than the bristle carrier 10.

[0106] The bristle tufts 24 have opposite ends and protrude slightly from the magazine 20 with their rear ends 28, called fastening ends; they thus project slightly beyond the front face 22. This is in Figure 1b shown.

[0107] Magazine 20, which is fully equipped with the bristle tufts 24, is transported laterally into the melting station 16, as in Figure 1cAs shown, this station includes a heating device 30, which can be, for example, a plate heater or a hot air heater. The rear ends 28 of the bristle tufts 24 are heated without contact, causing the individual bristles to exceed their melting point and the bristles of a tuft to fuse together to form a thickened attachment end. The bristles of a bristle tuft 24 are thus integrally bonded. The thickening 32 of a bristle tuft 24 does not extend into adjacent thickenings of neighboring bristle tufts 24, but remains spherical or lenticular thickenings. Preferably, no plunger is pressed against the thickenings or the still-liquid material of the molten bristle ends.

[0108] Several bristle tufts 24 can be anchored in the same bristle carrier 10, wherein at least one bristle tuft 24 consists of bristles made of a different material with a different melting point than the bristles of at least one other bristle tuft 24. The bristle tufts 24, consisting of different bristle materials, are heated to different temperatures in order to fuse the bristles of each tuft together to form a thickened attachment end. This can be implemented in various ways: The distance between the end of the bristle tuft 24 facing a heating device 30 and the heating device 30 is adjusted differently depending on the bristle material, and / or the heating device 30 is heated to different temperatures depending on the bristle material, and / or different heating devices 30, heated to different temperatures and adapted to the associated bristle material, are used.

[0109] For example, the bristle tufts are pushed out of the magazine 20 to different distances depending on the bristle material. Those bristle tufts 24 made of a more easily melting material, for example, remain closer to the magazine 20 than the others, so that the bristle tufts 24 that are extended further come closer to the heating element 30 than the others and are therefore heated more.

[0110] Alternatively, the bristle tufts 24 can also be processed one after the other by pushing the bristle tufts 24, which have different bristle materials, out of the magazine one after the other with their fastening end, in order to then get closer to the heating device 30. Either the heating device 30 is then heated to two suitable, different temperatures, or heating devices 30 at different temperatures are used for their respective assigned bristle tufts.

[0111] The pushing out of individual or groups of bristle tufts is done, for example, with a split base plate 44 (see Figure 5 ), the parts of which can be moved independently of each other in the longitudinal direction of the bristles.

[0112] For example, in a brush with nylon and PBT bristles, the nylon bristles are heated first, followed by the PBT bristles.

[0113] The thickenings 32 can optionally be actively cooled while still in the melting station 16, on the way to the subsequent anchoring station 18, or in the anchoring station 18 itself. This is done, for example, by a cold air stream 214 supplied by a fan (see Figure 1d ) or by designing station 1d as a cold chamber through which the magazine 20 with the still soft back-side thickenings 32 is passed. Cooling the thickenings 32 increases the cycle time.

[0114] The magazine 20 transports the bristle tufts 24 further into the subsequent anchoring station 18. This anchoring station ensures that the bristle tufts 24 are permanently fixed in the anchoring openings 12 of the bristle carrier 10 without anchors.

[0115] The anchoring station 18 comprises at least one bracket 34 (preferably several brackets 34) which is attached to its end face 36 opposite the end face 22 (see Figure 2 ) has a recess 38 (or several recesses if there are several bristle carriers 10 to be accommodated), which is designed to be complementary to the corresponding shape of the bristle carrier 10, so that it rests flat with its back side on the holder 34 (see also Figure 14 ).

[0116] The holder 34 itself has a flat front face 36, against which, however, the bristle carrier 10 protrudes slightly, as Figure 2shows, in order to protrude into the recess 200 in the magazine 20 which is complementary to the area of ​​the front of the bristle carrier 10, as is the case, for example, in Figure 14 shown.

[0117] Magazine 20 can be heated, for example either by an externally supplied plate heater, which is moved laterally to magazine 20 in the anchoring station 18 and can heat it up quickly, since magazine 20 is made of metal.

[0118] Alternatively, magazine 20 is equipped with a heater, in particular an electric resistance heater 39, which is Figure 2 and in Figure 14 The heating coils are symbolically indicated; they lie close to the front face 22 or, in the case of a recess 200, close to the bottom 202 of the recess 200, which forms part of the front face 22.

[0119] Electrical connection contacts 41, for example sliding contacts on a side surface of the magazine 20, make it possible to electrically connect the magazine 20 when it is moved into the anchoring station 18, in order to activate the heating element 39. Of course, it is also conceivable that the end face 22, including the base 202 of the recess 200, itself constitutes an electrical resistance heating layer, so that the end face is heated directly.

[0120] If the magazine 20 is fixed, the electrical connection for the heating is very easy to implement; it can be permanently installed.

[0121] The heating element 39 ensures that preferably the entire front face 22, which comes into contact with the bristle carrier 10, is heated, that is also the sections between the thickenings 32.

[0122] The temperature to which the end face 22 (in the area of ​​contact with the bristle carrier 10) is brought is below the melting point of the bristle and / or bristle carrier material, preferably of both materials. In particular, it is at most 85%, measured in °C, of ​​the respective melting point of these materials. For example, if both materials have a melting point of 100 °C, the temperature of the finally heated magazine 20 at the end face 22 will be at most 85 °C.

[0123] Figure 3 shows a cross-sectional view through anchoring station 18 in Figure 1e , before the magazine 20 and the bristle carrier 10 are driven towards each other.

[0124] The thickening 32 has such a dimension, viewed in the longitudinal direction A (also called axial direction or feed direction), that it is smaller than the corresponding cross-section of the anchoring opening 12, so that it can be inserted into the anchoring opening 12 without abutting or contacting the inner edge 40 of the anchoring opening 12. In particular, the cylindrical anchoring opening 12 has at this point only an excess of a maximum of 0.2 mm, more specifically a maximum of 0.15 mm, compared to the largest cross-section of the thickening 32 (fastening end).

[0125] The magazine 20, which is permanently heated to the desired temperature throughout operation, and / or the holder 34 are moved relative to each other. In this case, only the holder 34 with the bristle carrier 10 is moved, so that the thickening 32 first enters the anchoring opening 12 before the end face 22 contacts the flat end and front face 42 of the bristle carrier 10 facing it. During the delivery movement, the bristle carrier 10 is hardly heated at all as long as it is not in contact with the magazine 20, since the delivery movement is very rapid and there is no dwell time in the Figure 3 The open position of anchoring station 18 is shown.

[0126] A base plate 44 (see Figure 3The base plate 44, on which all the bristle tufts 24 rest with their front, end-facing, free ends and which forms a support, can serve to align the bristle tufts 24 with each other at their front ends and simultaneously create a distance, if desired, between the thickening 32 and the end face 22. The base plate 44 serves as a support for the individual bristles and for the bristle tufts 24.

[0127] In Figure 4 It is shown that the front face 22 contacts the front face 42 of the bristle carrier 10 and thus heats the bristle carrier 10 over the entire contact area between the two parts.

[0128] The bristle carrier 10 is made of thermoplastic material, in particular of the previously mentioned plastics such as polypropylene, ABS, PA, PBT, PET or PC.

[0129] However, the movement of the bracket 34 does not remain in the position of the first contact, which is in Figure 4This is shown because a very high pressure is applied to the bristle carrier 10 via the holder 34 and the magazine 20.

[0130] For example, as the two parts move towards each other, a pressure of at least 200 bar, preferably at least 400 bar, is exerted on the bristle carrier 10. This pressure is applied from the very first contact between the bristle carrier 10 and the magazine 20 and remains constant throughout the exposure time (contact time).

[0131] This pressure is maintained while simultaneously heating the bristle carrier 10 for an exposure time of at least 4 seconds, in particular at least 5 seconds and a maximum of 15 seconds, in particular a maximum of 10 seconds.

[0132] The contact time consists of a holding time and a time period (called the compression time) during the feed movement, which begins when the front 42 of the magazine 20 and simultaneously the rear of the bristle carrier 10 make contact with the holder 34. The compression time ends when the fully retracted position is reached and the distance between the holder and the tool part is kept constant for the holding time. The holding time is the time during which the feed movement is complete, i.e., the device is fully closed, and the bristle carrier 10 is received in the closed cavity. This holding time is preferably at least 1 second, preferably at least 1.5 seconds and / or a maximum of 3 seconds, and in particular a maximum of 2.5 seconds.

[0133] During the compression phase, the distance between the holder and the tool part is reduced extremely slowly and at a constant speed. For example, a total compression distance of 0.3 mm is covered in as little as 3 seconds.

[0134] During the exposure time, the magazine 20 is preferably kept heated, although the large mass of the magazine 20 might also allow the additional heating to be stopped after the initial heating to operating temperature. Nevertheless, the bristle carrier 10 would still continue to be heated during the exposure time.

[0135] The device is driven in particular onto a block, i.e., the holder 34 contacts an end face 36 outside the cavity formed by the recess 38 and the depression 200 (see Figure 14) the section of the front face 22 outside the recess 200. In this contact area no gap is provided into which material could penetrate from the cavity; rather, the cavity is sealed by a ring-shaped circumferential contact area.

[0136] Furthermore, preferably generally, and not limited to the embodiment shown, no heating is present in the contact area between holder 34 and magazine 20, so that the heating is only present and effective in the area of ​​the contact between front side 42 and magazine 20.

[0137] The separating plane between holder 34 and tool part (here magazine 20), which is defined by the end face 36, is preferably located closer to the front 42 than to the back of the bristle carrier 10. More precisely, the separating plane lies just or immediately adjacent to a rounded transition between the side surface 212 connecting the front 42 and the back.

[0138] It is advantageous if the support in the form of the base plate 44 is removed at least during the final phase of applying the pressure force, i.e., at the end of the dwell time, and no longer contacts the bristles. This improves the alignment accuracy of the bristles both with each other and relative to the bristle carrier 10. Preferably, however, the base plate 44 is removed before the start of the dwell time or even before the dwell time, as shown in the Figures 3-5 symbolically represented by the arrow Y. For example, the base plate 44 is only used in station c) and, if applicable, d) according to Figure 1 used.

[0139] However, in order to maintain the axial position of the bristle tufts and individual bristles throughout the entire exposure time, the cross-section of the receiving opening 26 and the cross-section of the bristle tuft 24 inserted therein are matched so that the bristle tuft 24 is clamped in the receiving opening 26 and thus axially securely positioned. The bristle tuft 24 is not displaced by its own weight or by inertia during movement within and between stations.

[0140] In the example given, the entire flat front surface, at least where it makes contact with the magazine 20 at the front 42 of the bristle carrier 10, is heated. If the magazine 20 has a recess 200, it is sufficient and advantageous to have the heating element only in the area of ​​the bottom 202 of the recess 200. However, since the magazine 20 is usually made of steel, the entire magazine 20 is heated. The temperatures being set are intended to bring the front 42 of the bristle carrier 10 to the desired temperature.

[0141] The temperature to which the bristle carrier is heated in the area of ​​the front 42 during the exposure time is below the melting temperature of the bristle and / or bristle carrier material, in particular at or below 85% of the respective melting temperature, calculated in °C. This temperature therefore corresponds to the previously mentioned maximum operating temperature of the magazine 20 in the area of ​​the front 22 or the bottom 202.

[0142] Alternatively, at least the edge 50 of the anchoring opening 12 in the area of ​​the front 42 can be heated, which forms the area of ​​the wall of the anchoring opening 12 that borders the opening to the front 42.

[0143] The temperature to which the bristle carrier 10 is heated, at least in the region of the edge 50, preferably in the entire contact area with the magazine, should not only be below or significantly below the melting point of the materials, but also within the range of the glass transition temperature of the bristle carrier material. With extremely high pressure, e.g., above 600 bar, it would be possible to heat the bristle carrier 10 in the region of the front face 42, at least in the region of the edge 50, only to a temperature above a limiting temperature that is 60% in °C, and in particular 80% in °C, of ​​the glass transition temperature of the bristle carrier material, if the bristle carrier material has a glass transition temperature of 300 K or greater. Preferably, however, this limiting temperature is at or slightly above the glass transition temperature.For a bristle carrier material with a glass transition temperature of less than 300° K, the heating temperature is a maximum of 50% above the glass transition temperature in ° K.

[0144] Another variant provides that the heating of at least the edge 50 of the front side 42, in particular the entire contact surface of the bristle carrier 10 in the area of ​​the front side 42, is heated to a temperature that is at least 30 °C above the ambient temperature, in particular before the edge 40 inside the anchoring opening 12 is heated above the ambient temperature by the magazine 20.

[0145] As can be seen in the figures, the magazine 20 has no extensions or the like with which it would protrude into the anchoring opening 12, since it has a flat front face 22 or a flat bottom 202 in the area of ​​the front 42.

[0146] Since the front surface 42 is also flat and there is no collar or similar feature in the area of ​​the opening of the anchoring opening 12, i.e., in the area of ​​the edge 50, as was the case in the prior art, the bristle carrier material in the area of ​​the front surface 42 is deformed across its entire surface during the application of pressure and temperature. The material tends to move out of the way and thus migrates into the anchoring openings 12 in the area of ​​the opening, constricting them.

[0147] By applying heat and pressure, the overall thickness D, and thus the maximum thickness of the bristle carrier 10, is permanently reduced in the area of ​​the opening of the anchoring aperture 12 towards the front 42. This creates a kind of constriction that engages behind the thickened fastening end in the pull-out direction, thereby securing the bristle tuft 24.

[0148] No adhesion occurs between the thickened fastening end and the wall of the anchoring opening 12.

[0149] The reshaping of the edge need not be extreme. It has been found that, for example, in the case of toothbrushes, it is sufficient to maintain the cross-section of the anchoring opening 12 with the original width or the original diameter D3 in the area of ​​the edge 218 (see Figure 5A ) only to reduce to a width or an inner diameter D1 to such an extent that the difference between the width or diameter D2 of the thickest point of the thickening 32 (relative to the respective cross-sectional plane) and the width or diameter D1 in the area of ​​the edge 218 is only about 0.1-0.5 mm.

[0150] It is advantageous if the thickening 32 has an undersize compared to the still undeformed anchoring opening 12 when inserted (i.e. D2 is smaller than D3).

[0151] However, this is not mandatory. For example, there may be a minimal lateral offset of the thickening 32 relative to the anchoring opening 12, even though the thickening 32 is undersized and a circumferential gap should exist between the thickening at its thickest point and the inside of the anchoring opening 12. Due to this offset, the thickening may come into contact with the wall of the anchoring opening 12 on one side when inserted. In this context, it may be advantageous for the material of the thickening to not have fully solidified to the inside when the thickening 32 is inserted into the anchoring opening. For example, if the thickening forms a relatively thin, cooled skin on the outside and is still very soft inside, the skin, along with the interior of the thickening, will simply be deflected inwards without damaging the thickening itself.It is still suitable to be fully gripped from behind by the deformed edge.

[0152] This idea of ​​inserting the thickening 32 into the anchoring opening 12 in a not yet fully solidified state also makes it possible in general to use a thickening 32 which is designed with an excess compared to the cross-section of the anchoring opening 12, i.e. D2 greater than or equal to D3.

[0153] In Figure 5A The space formed by the anchoring opening 12 and delimited to the outside by the narrowed edge 218 for accommodating the thickening 32 is exaggerated, as is the thickening 32 in relation to the diameter D1.

[0154] However, the fact is that not the entire wall forming the anchoring opening 12 rests against the thickening 32 or against the outer bristles extending from the thickening 32. Rather, the wall is only reshaped in the area of ​​the edge 218 and in an immediately adjacent section 220 that widens outwards towards the base 208, and only in these areas does it rest against the bristles or the thickening 32 and exert pressure on them.

[0155] However, the thickening should contact the base 208 in order to precisely determine the axial position of the bristle tuft.

[0156] In the remaining area, for example between base 208 and thickening 32 or in the area of ​​the circumference of the wall adjacent to base 208, there are one or more air gaps 222 between the wall and the outside of the thickening 32, so that it is not compressed, jammed and / or deformed in this area.

[0157] In the area of ​​the edge 218, the bristle tuft 24 is compressed compared to its state in the magazine 20 by narrowing and constricting the edge 218 by at least 3%, in particular at least 5%. Here, the cross-sectional area of ​​the receiving opening in the magazine is compared with the cross-sectional area of ​​the edge 218 at its narrowest point.

[0158] All anchoring openings 12 are closed simultaneously by the device and the corresponding method shown, thereby anchoring all bristle tufts 24 in the bristle carrier 10 at the same time.

[0159] As further in Figures 4 and 5A As can be seen, the entire anchoring opening is not reshaped, but only up to a certain depth t, which corresponds to a maximum of 85%, in particular 70%, of the total depth T of the anchoring opening 12 and / or which has an axial extent of 0.5-1.3 mm, in particular 0.6-0.9 mm.

[0160] The thickening 32 itself is preferably clamped in the anchoring opening only in the axial direction over a maximum of 50% of its total axial length. The remainder of the clamping takes place in the area of ​​the bristles emanating from the thickening 32.

[0161] The wall of the anchoring opening 12 is reinforced to a depth Z (see Figure 5A ) of at least 0.8 mm, starting from the base 208, is not deformed and / or the thickening 32 and the bristles in this area are not jammed.

[0162] The depth T of the anchoring opening after the manufacture of the brush is a maximum of 4 mm, in particular a maximum of 2.7 mm.

[0163] All anchoring openings 12 are blind holes, so that the bristle carrier 10 does not need to be covered on the back, as no parts of the bristle tufts are visible or protrude on this side.

[0164] The anchoring created in this way is the only anchoring for the bristle carriers; no metal anchor or metal wire is necessary.

[0165] It should be emphasized generally, and this does not only apply to the illustrated embodiments, that the bristle carrier 10 should not be heated close to its melting temperature, but rather significantly away from it, close to its glass transition temperature. In particular, the heating temperature, and thus also the temperature at the magazine 20 in the area of ​​the end face 22 and the end face of the bristle carrier 10, should not exceed 15% above the glass transition temperature of the bristle carrier material and / or the bristle material.

[0166] When using PET, according to a preferred embodiment of the invention, the front surface 42 is heated to a temperature of 75-95 °C, particularly 80-90 °C, during forming; when using PP, it is heated to a temperature of 105-125 °C, particularly 110-120 °C. The PP is selected, in particular, to have a melt flow index (MFI) of 6-35, preferably 10-15, in its initial state.

[0167] One embodiment of the invention provides that the end face 22, and thus the bristle carrier 10, is heated to a temperature of at most 140 °C, in particular at most 130 °C, preferably in the range of 100 to 115 °C. Polypropylene, PET, ABS, copolyester, and SAN are particularly suitable materials for the bristle carrier.

[0168] The rear side 206 of the bristle carrier 10 and the area extending from the rear side 206 to at least the base 208 of the anchoring openings 12 (preferably even further towards the front side 42) should not be deformed. To shift the temperature limit at which deformation would occur due to the applied pressure as close as possible to the front side 42 of the bristle carrier 10, the holder 34 can be equipped with active cooling.

[0169] In the Figures 3 and 14 This cooling is symbolized by cooling channels 210 through which coolant flows. The cooling channels 210 are connected to a cooling water circuit that pumps cold water, preferably below 20°C, and in particular even below 10°C, through the holder 34. The rear surface 206 thus reaches a maximum temperature of 25°C during the application of the pressure force. The side surface 212 connecting the front surface 42 and the rear surface 206 (see Figure 14) of the bristle carrier 10 can be sufficiently cooled in the holder 34 so as not to be deformed and to remain below the corresponding temperature at which deformation would occur.

[0170] After the specified exposure time, holder 34 and magazine 20 are moved apart again, so that the bristle tufts 24 are pulled out of their receiving openings 26. No further processing in the form of reshaping the bristle carrier 10 is required.

[0171] The separation process is preferably not carried out in one go, but rather a resting phase is incorporated into the separation process. For this purpose, the tool part, i.e., magazine 20, and the holder 34 are moved minimally apart, so that a small ventilation gap 228 exists between the front 42 and the top of the tool part, i.e., the magazine 20 (see figure). Figure 5A) of greater than or equal to 0.5 mm. When this predetermined ventilation gap 228 is reached in height, the distance preferably remains constant for the rest phase, which is at least 1 second, in particular at least 1.5 seconds.

[0172] Optionally, during this rest phase, cooling air can also be blown to the front of the bristle carrier 10 via the ventilation gap 228 to cool the front.

[0173] During this resting phase, however, the bristles remain in the intake opening 26, as shown by this Figure 5A shows. During the resting phase, the reshaped area of ​​the anchoring opening stabilizes, so that the bristles of a tuft run parallel to each other and in a uniform direction.

[0174] After the resting phase, the device is moved apart so that the finished bristle carrier can be removed.

[0175] To precisely control the corresponding movements and temperatures, the device has a control unit 51, which controls not only the heating temperature but also the applied pressure and the movement sequences. The heater 30 can also be controlled via the same control unit 51.

[0176] Regardless of the bristle carrier material, the following applies: In the delivery movement from the magazine 20 relative to the holder 34 and thus to the bristle carrier 10 (the relative movement of the parts means that one or both of these parts can be moved in the direction of the other part), a pressure- and time-controlled delivery movement and / or a pressure- and distance-controlled delivery movement can be advantageous.

[0177] In particular, it is advantageous if, in a first phase of the delivery movement, the rim 50 or the entire front surface 42 is heated to a temperature above a limiting temperature. This limiting temperature is 60%, and in particular 80%, below the glass transition temperature of the bristle carrier material, determined in °C if the bristle carrier material has a glass transition temperature above 300 K. Preferably, however, the limiting temperature is at a glass transition temperature, or at most up to 20% above, the glass transition temperature in °C. In a subsequent second phase of the delivery movement, the rim 50 is then deformed and pressed against the bristles.

[0178] Alternatively, the delivery movement takes place at a constant, low speed when the bristle carrier is contacted at the front and rear and thus axially compressed, and the magazine 20 and the holder 34 are brought into contact with each other.

[0179] Even in the Figure 5 In the illustrated embodiment, when closed, the material in the area of ​​the edge 50 presses against the bristles, so that there is no gap between the bristles and the edge 50.

[0180] Magazine 20 can be loaded either as shown in Figure 1a directly via a bristle singulator, or via another variant that is in Figure 6 As shown, a cassette 60 with numerous receiving openings is first filled with bristle tufts. The individual bristle tufts can then be stored in this cassette until they are finally pressed directly into the magazine 20, for example, via movable pins 62.

[0181] Alternatively, a deflection plate 64 can be provided between the cassette 60 and the magazine 20, which has angled transport openings 66 for bristle tufts 24 moving through it. It is also possible to use converging transport openings 66, as in Figure 6As shown on the left, several bristle tufts 24 can be combined into a larger bristle tuft, for example, if the brush is to contain bristle tufts of varying thicknesses. Furthermore, the magazine can, of course, also have slanted receiving openings 26, because there are brushes in which the bristle tufts do not run perpendicular to the front 42, but are arranged at an angle to it. Here, too, the anchoring is as shown in the figures. Alternatively, the anchoring openings 12 for such slanted bristle tufts 24 can, of course, be slightly slanted or conical, or conical only in the area of ​​the side of the bristle tuft 24 facing them, as shown in Figure 7 is shown.

[0182] In Figure 8An anchoring opening is shown, which has an edge section 80 in its interior that runs obliquely to its front face 42 opposite the tool part. Before the bristle carrier is acted upon by the tool part, it has a projection 82 on its end face 50 in the area of ​​the obliquely running edge section 80, projecting towards the tool part opposite the front face 42, and otherwise a flat front face 42.

[0183] The bristle carrier 10 in the Figures 9 and 10The bristle carrier 10 is produced in an injection molding station belonging to the device according to the invention, using an injection mold with mold halves 100 and 102. This injection molding station is located upstream of the previously described station for stuffing the bristle carrier 10. These mold halves 100 and 102 form a cavity 104 between them, into which liquid plastic is injected to produce the bristle carrier 10. While previously used injection molding stations had mold half 100 equipped with pin-shaped, active slides that projected through the mold half 100 into the cavity 104 and were withdrawn before the mold was opened, this variant provides a much simpler solution. Here, one or more extensions 106 are fixedly attached to the mold half 100, projecting freely into the cavity 104. These extensions 106 then create the anchoring openings 12.The depth of the anchoring openings 12 is significantly less than in previously manufactured bristle carriers that were packed using anchor technology. Alternatively, the base of the injection mold half 100 can accommodate a movable insert 107 (see dashed lines in ). Fig. 10 ) on which the extensions 106 are located. After injection molding, the insert 107 is pulled downwards into a recess in the injection mold half to facilitate demolding, so that the extensions are also pulled out of the injected anchoring openings 12, thus simplifying the subsequent removal of the bristle carriers 10.

[0184] Figure 9Figure 1 shows various ways in which the bristle carrier 10 can be designed. Not only circular or oval anchoring openings 12 can be provided, but any shape can be created. For example, elongated openings, X-shaped, C-shaped, or any other shaped anchoring openings are possible. These large anchoring openings are fitted with bristle tufts, which are composed of several individual bristle tufts that are joined together by melting their ends to form a large bristle tuft. Such large bristle tufts result in a corresponding wall-like bristle structure.

[0185] It should be emphasized that the device and method according to the invention can be used not only with several tufts of bristles, but also with only one tuft of bristles, for example to produce a brush, and to attach only one or only individual bristles in a bristle carrier.

[0186] The anchoring openings 12 do not necessarily have to serve only for receiving and fixing bristle tufts; rather, prefabricated, singular bristles of any shape, made from any elastomeric plastic, can be received and fixed exactly as previously described in connection with bristle tufts. These bristles can have a plate-like shape and can, for example, be inserted into the elongated anchoring openings 12 and embedded therein by reshaping the edge of the anchoring openings 12. For example, a pre-injected cleaning element with a C-shaped cross-section is inserted as a singular bristle into the C-shaped anchoring opening 12. Additionally, bristle tufts 24 consisting of numerous bristles 24' can, of course, also be inserted into the bristle carrier 10. The singular bristles 24' can, for example,also be positioned in the middle of a field of bristle tufts 24 or conversely surround single or several bristle tufts 24.

[0187] It should be emphasized that the aforementioned characteristics, which were explained using the bristle tufts as an example, can also be applied to singular, large bristles. As just one example, consider a plate-shaped bristle running obliquely to the bristle carrier 10, which is inserted into the oblique anchoring opening 12 in the Figures 7 and 8 The single bristle can, however, also have an anchoring end 32 from which the elongated remainder projects at an angle, so that it fits into a cylindrical anchoring opening 12 according to Figure 4 can be inserted, but the bristle runs diagonally outside the anchoring opening 12.

[0188] The singular, separately manufactured bristle 24' or bristles 24' are preferably fixed simultaneously with the bristle tufts 24 by forming the corresponding edges of the anchoring openings 12 in the bristle carrier 10. Alternatively, it is possible to perform several separate, successive forming operations for the different bristles or bristle tufts. Different pressures and / or temperatures can also be applied by the heated tool part(s) if the bristles or bristle tufts are made of different materials.

[0189] In addition to or as an alternative to the above variants, elastomeric cleaning elements 108 can, for example, be injection-molded onto the edge of the bristle carrier 10. These cleaning elements 108 are not prefabricated, but they also protrude from the front opposite the bristle carrier 10 and serve to massage the gums.

[0190] The bristle carrier 10 can, for example, have holes or only edge-side recesses into which the cleaning elements 108 are injected. Furthermore, as is increasingly common with brushes, the back of the bristle carrier 10 can also be overmolded with a softer plastic.

[0191] In the latter case, it is advantageous for the cleaning elements 108 to merge seamlessly into the softer plastic layer on the back. As can be seen from the upper half in Figure 9 As shown, which depicts a variant of the lower half, this rear layer made of softer plastic can also form a kind of frame around the harder plastic of the bristle carrier 10, for example to act as a damper.

[0192] Another variant consists in the bristle carrier 10, here the head of the toothbrush, being coupled to the neck of the brush body via a hinge 110 made of softer plastic.

[0193] In general, for all variants, the bristle carrier can be a plate as part of the later brush body or the entire brush body itself. For example, the bristle carrier can also be a multi-component injection-molded part, which then already forms the finished brush body when the bristles are finally embedded. Conversely, it is also possible to embed the bristles in a part of the brush body that then forms the bristle carrier and subsequently overmold this bristle-covered bristle carrier.

[0194] Therefore, the spray station can also be designed as a multi-component spray station, or several spray stations can be provided, with the station in which the bristles are anchored located between them.

[0195] The cleaning elements 108 and / or the singular, prefabricated bristles of elastomeric material of any cross-sectional shape extend forward preferably at least as far as the bristle tufts, but they can also extend beyond them or be shorter than them.

[0196] In Figure 11 It is shown that not only are bristle tufts 24 with their thickening 32 at the attachment end inserted into the anchoring opening 12 and anchored therein by deforming the edge, as previously explained, but also that singular, prefabricated bristles 24' (of any shape, both in side view and in cross-section) can be embedded anchorless in the bristle carrier using the aforementioned method and device. The bristles 24' are injection-molded from an elastomeric material, in particular TPE.

[0197] The bristles 24' have a maximum wall thickness d (measured in cross-section) in their section projecting from the bristle carrier 10, which is greater than 0.6 mm, in particular greater than 0.9 mm.

[0198] Furthermore, the pre-formed bristles 24' can or should have a thickened attachment end 32' whose height is less than the depth of the associated anchoring openings 12, so that the inwardly formed edge engages the attachment ends 32' to achieve a positive-locking hold. The attachment ends 32' are, for example, flat cylinders whose shape is adapted to the shape of the anchoring opening 12. However, the outer dimensions of each attachment end 32' are such that, upon insertion, a lateral gap exists between the attachment end 32' and the wall of the anchoring opening 12 before the forming process takes place.

[0199] The attachment end 32' can be made of a different material, in particular a harder material, than the rest of the bristle 24'. An example of this would be an attachment end 32' made of polypropylene. Alternatively, only the core of the bristle 24' can consist of a harder material, which is then subsequently overmolded with a softer material. Thus, a disc of harder material could form the entire core or all of the attachment end 32'.

[0200] Similarly, according to Figure 12 On the left, the core-forming disc 112 has an integrally formed extension 114 which projects into the part of the bristle 24' that will lie outside the bristle carrier 10.

[0201] The in Figure 12 The variant of a bristle 24' shown on the right is formed with a fastening end 32' made of a hard plastic and a section 118 made of a softer plastic that is molded onto it.

[0202] The in Figure 12The depicted singular bristles 24' are tapered, which is not to be understood as restrictive.

[0203] For example, on a toothbrush, elastomeric areas are often injected onto the back of the bristle holder, extending further than the rest of the bristle holder 10, which serve as a tongue cleaner, as is the case in Figure 15 The elastomer 232 can have bumps or ribs. The recess 38 in the holder 34 is designed in the area of ​​the outer surface of the elastomer 232 to be complementary to the shape of the elastomer 232 in the uncompressed state. However, the volume allocated to the elastomer 232 for the compressed state (closed state of the device, see figure) is Figure 15The height allowed for the elastomer 232 is less than in the unloaded state. This means that the height allowed for the elastomer 232 is reduced to the compression under the desired pressure. Optionally, during deformation, the entire counter-pressure can even be transferred from the holder 34 to the bristle carrier 10 via the elastomer 232.

[0204] In Figure 13 A complete device with various stations is shown. It should be emphasized that the device according to the invention does not necessarily have to include all the stations that will be explained below.

[0205] In particular, all variations and details explained with reference to the preceding figures, especially with reference to Figure 1 , also in this embodiment, can be implemented individually or in combination, regardless of whether this includes, for example, cooling, ventilation, etc., as well as the previously mentioned temperatures, temperature ranges or times and the materials used.

[0206] In station A, bristles or bristle tufts are separated and transported further. The left image shows a so-called fiber box 120, from which finished bristles, which may be mechanically or chemically pointed, are taken in tufts by a tuft separator 122.

[0207] These bristle tufts 24 are transported via a transport device to a station B, where the bristle tufts 24 may then already be transformed into the final tuft geometry and the hole pattern of the later brush.

[0208] For example, the bristle tufts 24 are inserted into a first intermediate magazine 124, in particular in the form of a plate. Via the intermediate magazine 124, the bristle tufts 24 are then, if necessary, pushed by means of a plunger 126 into a further plate 128, in which forming or deflection openings 130 or openings 132 for combining several bristle tufts 24 into a common larger bristle tuft or for aligning bristle tufts 24 at an angle are provided.

[0209] The bristle tufts 24 are then pushed further into the magazine 20. The hole geometry of the later brush is preferably implemented in the magazine 20, but this is not mandatory, as will be explained later.

[0210] However, if necessary, the plate 128 and / or the intermediate magazine 124 can also be omitted, so that the bristle tufts 24 are transported directly into the magazine 20. This all depends on the desired final tuft position or tuft geometry and the hole pattern of the finished brush.

[0211] The transport of the bristle tufts 24 after singulation can be carried out mechanically via slides or the in Figure 2 The plunger 126 shown is used to convey the individual bristle tufts into the first intermediate magazine 124 and / or magazine 20 in station B. In station A, as a further alternative shown in the second image from the left, the individual bristle tufts are conveyed into the intermediate magazine 124 or magazine 20 via tubes or hoses 134, in which an overpressure or underpressure is applied.

[0212] Regardless of the means of transport used for the bristle tufts, they can be fed in individually one after the other, in groups one after the other or all at once and / or inserted into the magazine 20.

[0213] A third alternative in station A shows a wound strand 136 of parallel filaments. The strand 136 is wound onto a spool 138 and is continuously unwound from it. The end of the strand 136 is inserted into openings in an intermediate magazine 124 or the magazine 20 and then cut off. After the ends of the strand are cut, tufts of bristles 24 are produced. For example, a movable XY table then moves either the spool or the end of the strand, which is held in a movable guide, relative to the magazine 20 or intermediate magazine 124, or the magazine 20 / intermediate magazine 124 is moved relative to the end of the strand, so that all openings in the magazine 20 or intermediate magazine 124 are filled sequentially. Furthermore, several spools and strands can also be moved relative to the magazine 20 / intermediate magazine 124.The fully loaded magazine 20 or intermediate magazine 124 is then moved out of this station and transported to station B or directly to station C. In station B, the plungers 126 press the bristle tufts 24 into the magazine 20.

[0214] To avoid the need for the XY table, strands can also be transported simultaneously from several rolls 138 into the individual openings in the magazine 20 or the intermediate magazine 124 and then cut off.

[0215] Station C is a so-called profiling station. Here, the bristle tufts 24 are axially displaced so that the later ends of the tufts used for brushing lie in one plane or, more generally, end in a predetermined, arbitrary surface.

[0216] In the illustrated embodiment, a wave shape is predetermined, which is why a stop plate 140 with a complementary wave shape is spaced apart from the magazine 20. The bristle tufts 24 are then pressed downwards by a pressure plate 142, which preferably has a shape complementary to the surface of the stop plate 140, until all tuft ends are in contact with the stop plate 140.

[0217] Station C can be omitted if the desired profile can already be achieved in Station B using suitable plungers 126 of different or equal lengths. The two variants can also be combined by performing a pre-profiling in Station B using plungers 126 of different lengths, followed by fine profiling in Station C using the stop plate 140.

[0218] Station D is a cutting station where the rear ends of the bristle tufts are cut off to ensure optimal melting of the tuft ends in the subsequent station. The bristle tufts 24, which may protrude at varying distances from the magazine 20, are cut off mechanically using a knife 144 or thermally with a hot wire 146 relatively close to the magazine 20. If a mechanical knife 144 is used, the magazine 20 can also act as a counter-knife. In this case, the bristle tufts 24 are pushed slightly out of the magazine 20 after cutting so that they protrude a little beyond it.

[0219] Station D can be omitted if the tuft ends already protrude uniformly far to the rear of magazine 20 after station B or C. This is particularly the case if the front tuft ends are to terminate in the same plane.

[0220] The protruding section of the bristle tufts 24 is then melted in station E, so that all filaments of a tuft are connected to each other via the resulting mushroom-shaped, thickened tuft end. The thickness of the tuft ends is controlled by the amount of filament material protruding from the rear side opposite the magazine 20. This also allows the geometry of the tuft end to be adjusted.

[0221] The fusing can be carried out by a heated stamp 148, which can either touch the tuft ends or remain spaced away from them, so that the filaments melt through radiant heat (especially via infrared light). Alternatively, fusing can also be achieved with hot air. It is important that only a single, associated thickening is created for each bristle tuft, because only those filaments that are later to be fixed in the same anchoring opening should be joined together by fusing. If necessary, the thickenings 32 can be cooled, as previously explained.

[0222] In the subsequent station F, the bristle tufts, with their thickened attachment ends first, are inserted into the anchoring openings 12 of the bristle carrier 10 and pressed in place as previously explained in detail. This insertion can be carried out simultaneously, sequentially, or sequentially in groups.

[0223] Another alternative involves using a deflection plate with corresponding channels into which the bristle tufts 24 are inserted with their thickened attachment ends first, and then further pushed into the anchoring openings of the bristle carrier. This variant is suitable when the magazine does not yet fully realize the final hole pattern of the brush or the orientation of the bristle tufts 24.

[0224] The aforementioned separately manufactured, singular bristles 24' can be fed into any station, either into the magazine 20 or first into the bristle carrier 10.

[0225] The pressing force is achieved, for example, via at least one drive, e.g., an electric motor 240 (see Figure 1f ) preferably applied to the holder 34, optionally with the interposition of a gearbox such as a spindle nut 242. This naturally applies to all embodiments.

[0226] The electric motor is specifically a servo motor.

[0227] In general, several bristle carriers 10 can be deformed simultaneously with one drive in order to hold at least one bristle or at least one bristle tuft 24 in the anchoring opening. For this purpose, the holder 34 has several recesses 38 shaped complementarily to the bristle carrier.

[0228] To increase the output of finished brushes, several drives are provided side by side, which in turn drive several holders 34, which in turn hold several bristle carriers 10.

[0229] The control unit 51 is programmed to perform the aforementioned procedure in the device.

[0230] With the device and method according to the invention, bristle tufts that are extremely long and thin can be anchored in the bristle carrier. The invention provides bristle carriers with bristle tufts longer than 8 mm and wider than 2 mm, in particular less than 1 mm.

[0231] With these large edge lengths, the corresponding edges of the anchoring openings do not necessarily need to be shaped inwards by the same distance. It has been found that it is sufficient to provide some overhanging edge sections that are deformed further inwards towards the anchoring opening, alternating with edge sections that are deformed less inwards.

[0232] Another alternative involves using a deflection plate with corresponding channels into which the bristle tufts 24 are inserted with their thickened attachment ends first, and then further pushed into the anchoring openings of the bristle carrier. This variant is suitable when the magazine does not yet fully realize the final hole pattern of the brush or the orientation of the bristle tufts 24.

[0233] The aforementioned separately manufactured, singular bristles 24' can be fed into any station, either into the magazine 20 or first into the bristle carrier 10.

[0234] The pressing force is achieved, for example, via at least one drive, e.g., an electric motor 240 (see Figure 1f ) preferably applied to the holder 34, optionally with the interposition of a gearbox such as a spindle nut 242. This naturally applies to all embodiments.

[0235] The electric motor is specifically a servo motor.

[0236] In general, several bristle carriers 10 can be deformed simultaneously with one drive in order to hold at least one bristle or at least one bristle tuft 24 in the anchoring opening. For this purpose, the holder 34 has several recesses 38 shaped complementarily to the bristle carrier.

[0237] To increase the output of finished brushes, several drives are provided side by side, which in turn drive several holders 34, which in turn hold several bristle carriers 10.

[0238] The control unit 51 is programmed to perform the aforementioned procedure in the device.

[0239] With the device and method according to the invention, bristle tufts that are extremely long and thin can be anchored in the bristle carrier. The invention provides bristle carriers with bristle tufts longer than 8 mm and wider than 2 mm, in particular less than 1 mm.

[0240] With these large edge lengths, the corresponding edges of the anchoring openings do not necessarily need to be shaped inwards by the same distance. It has been found that it is sufficient to provide some overhanging edge sections that are deformed further inwards towards the anchoring opening, alternating with edge sections that are deformed less inwards.

Claims

1. A method for producing a brush which comprises a bristle carrier (10) made from a thermoplastic resin having at least one anchoring opening (12), in which at least one bristle made from a thermoplastic resin is inserted and anchored therein without using an anchor, characterized by the following steps: the at least one bristle is accommodated in a receiving opening (26) of a tool part, the at least one bristle is inserted by its fastening end into an anchoring opening (12) in the bristle carrier (10), which has been formed during producing the bristle carrier (10), while the at least one bristle is still located in the receiving opening (26), without being fastened therein, the tool part is heated, so that the front face (22) of the tool part opposite the bristle carrier (10) is brought to a temperature that is below the melting temperature of the bristle material and / or of the bristle carrier material, in particular amounts to a maximum of 85% in °C of the respective melting temperature of the bristle material and / or the bristle carrier material, the tool part is moved relative to the bristle carrier (10), so that the tool part contacts and heats the bristle carrier (10), the tool part applies a pressure force on the bristle carrier (10) and reshapes the bristle carrier (10) at least in the region of the rim (50), which is encompassing the anchoring opening (12), while reducing the cross-section of the anchoring opening (12) in such a way that the at least one bristle is embedded and anchored in the anchoring opening (12), and the tool part is moved away in relation to the bristle carrier (10), so that the at least one bristle is pulled out of the receiving opening (26).

2. A method for producing a brush which comprises a bristle carrier (10) having at least one anchoring opening (12) and at least one bristle inserted into the anchoring opening (12) and anchored therein without using an anchor, wherein the bristle carrier (10) and the at least one bristle are formed from a thermoplastic resin which may be of the same kind or of a different kind, characterized by the following steps: the at least one bristle is accommodated in a receiving opening (26) of a tool part, the at least one bristle is inserted by its fastening end into an anchoring opening (12) of the bristle carrier (10), which has been formed during producing the bristle carrier (10), while the at least one bristle is still located in the receiving opening (26), without being fastened therein, a front face (22) of the tool part opposite the bristle carrier (10) is heated to a predetermined temperature, which is in a range of between ambient temperature and 210°C, preferably 150°C, the tool part is moved relative to the bristle carrier (10), so that the tool part contacts and heats the bristle carrier (10), but without melting the bristle carrier (10) and the at least one bristle, a pressure is applied to the bristle carrier (10) by the tool part, and the bristle carrier (10) is reshaped at least in the region of the rim (50) which is encompassing the anchoring opening (12), while reducing the cross-section of the anchoring opening (12) in such a way that the at least one bristle is embedded and anchored in the anchoring opening (12), and the tool part is moved away in relation to the bristle carrier (10), so that the at least one bristle is pulled out of the receiving opening (26).

3. The method according to any of the preceding claims, characterized in that the tool part is heated before it contacts the bristle carrier (10), in particular to its predetermined maximum operating temperature, and / or characterized in that the bristle carrier (10) is heated by the tool part only after inserting the at least one bristle.

4. The method according to any of the preceding claims, characterized in that the tool part heats the bristle carrier (10) in the region of the contact surface with the tool part during the feed motion of the tool part to the bristle carrier (10) and / or upon contacting the bristle carrier (10) to a temperature which is less than the melting temperature of the bristle carrier material and which is preferably equal to or higher than the glass transition temperature of the material of the bristle carrier (10), in particular for a bristle carrier material having a glass transition temperature of equal to or higher than 300° Kelvin is at maximum 15% above the glass transition temperature in degrees Kelvin, and for a bristle carrier material having a glass transition temperature of less than 300° Kelvin is at maximum 50% above the glass transition temperature in degrees Kelvin.

5. The method according to any of the preceding claims, characterized in that in a first phase of the feed motion relative to the bristle carrier (10), the tool part heats the bristle carrier (10) at least in the region of the rim (50) encompassing the anchoring opening (12) to a temperature above a threshold temperature which, for a bristle carrier material having a glass transition temperature equal to or higher than 300° Kelvin, is 40% in degrees Celsius, in particular 20% in degrees Celsius below the glass transition temperature of the bristle carrier material or which equals the ambient temperature for a bristle carrier material having a glass transition temperature of below 300° Kelvin, before the tool part reshapes the rim (50) in a second phase of the feed motion and the rim (50) presses against the at least one bristle.

6. The method according to any of the preceding claims, characterized in that the at least one bristle is first inserted into the receiving opening (26) before the tool part has contacted the bristle carrier (10), in particular before the bristle carrier (10) has been heated, at least in the region of the rim (50) encompassing the anchoring opening (12), to a temperature that is above a threshold temperature which, for a bristle carrier material having a glass transition temperature of equal to or higher than 300° Kelvin, corresponds to 60% in degrees Celsius, in particular 80% in degrees Celsius, of the glass transition temperature of the bristle carrier material, or which corresponds to the ambient temperature for a bristle carrier material having a glass transition temperature of less than 300° Kelvin.

7. The method according to any of the preceding claims, characterized in that the at least one bristle is first inserted into the receiving opening (26) before at least the rim (50) of the anchoring opening (12) is heated to a temperature which is at least 30°C above the ambient temperature, in particular before the rim (50) of the anchoring opening (12) inside the anchoring opening (12) is heated by the tool part above the ambient temperature.

8. The method according to any of the preceding claims, characterized in that the tool part is heated in the entire contact area in which the tool part contacts the bristle carrier (10), wherein the tool part contacts the entire front side facing the tool part, but at least at minimum 70% of the front side, and applies pressure to it.

9. The method according to any of the preceding claims, characterized in that the bristle carrier (10) includes a back side which is not heated by the tool part during anchoring.

10. The method according to any of the preceding claims, characterized in that during insertion into the anchoring opening (12), the fastening end of the at least one bristle or of a complete bristle tuft (24) is smaller than the cross-section of the anchoring opening (12), and / or that the at least one bristle or a complete bristle tuft (24) has a thickened fastening end generated by thermal reshaping of the bristle material, wherein when using a bristle tuft (24), the bristles of the bristle tuft (24) are fused with each other by thermal reshaping.

11. The method according to any of the preceding claims, characterized in that the tool part contacts the bristle carrier (10) over an application time of at least 5 seconds, in particular at least 6 seconds, and at maximum 15 seconds, in particular at maximum 10 seconds, in particular at a constant pressure and / or permanent heating of the bristle carrier (10).

12. The method according to any of the preceding claims, characterized in that the at least one anchoring opening (12) is a blind hole, in particular having a depth of maximum 4 mm, further in particular maximum 2.7 mm, and / or characterized in that the anchoring opening (12) is reshaped and constricted only to a depth of at maximum 85%, in particular at maximum 70% of its total depth, and / or characterized in that the tool part applies a pressure of at least 200 bar, in particular at least 400 bar, on the bristle carrier (10).

13. The method according to any of the preceding claims, characterized in that the tool part is a magazine (20) which is loaded with the at least one bristle or the at least one bristle tuft (24), wherein after the loading, the at least one bristle or the at least one bristle tuft (24) protrudes from the magazine (20) by its fastening end, and the fastening end is heated, and thus forms a thickening (32).

14. An apparatus for producing a brush comprising at least one bristle or at least one bristle tuft, which brush includes a bristle carrier (10) having at least one anchoring opening (12) for the at least one bristle or the at least one bristle tuft (24), for carrying out the method according to any of the preceding claims, characterized in that the apparatus comprises a holder for the bristle carrier (10) and a tool part in the form of a press punch having at least one receiving opening (26) for the at least one bristle or the at least one bristle tuft (24), wherein the receiving opening (26) ends on the front face (22) of the tool part facing the bristle carrier (10), and wherein the tool part includes a heating which heats at least portions of the front face (22), the heating being adapted and controlled in such a way that the front face (22) is heated to a temperature of at maximum 140°C, in particular at maximum 130°C.