METHOD AND DEVICE FOR MANUFACTURING A BRUSH

Description

[0001] The invention relates to a method and a device for producing a brush having 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, particularly toothbrushes, but also household brushes, two processes have become established in practice: attaching the bristle tufts using an anchor (metal plate or wire loop) or anchorless. In contrast to the use of an anchor, the anchorless process involves the bristle tuft not being folded and attached to the bristle carrier at its folding point, but rather being secured at one end to the bristle carrier by gluing or thermally locking. A common process that has become established in practice involves the bristle carrier having openings through which the bristle tufts are inserted. The rear ends of the bristle tufts then protrude from the openings and are heated on the back of the bristle carrier.The thermoplastic material of the bristles melts, causing the bristles to merge into one another and creating a thickening that makes it impossible to pull the individual bristles forward. Typically, the numerous bristle tufts are liquefied on the back using hot air or a hot stamp, so that the material of the individual bristle tufts merges into one another, creating a kind of layer of liquefied bristle ends on the back. This back surface is then covered, in particular, by overmolding.

[0003] The disadvantage of this solution is that the necessary back cover requires considerable additional processing and equipment. 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 carries the bristles or tufts of bristles. The bristle carrier can be the entire brush body—in the case of a toothbrush, the one-piece molded part consisting of the handle, neck, and head—or simply a prefabricated component of the final brush body. In the latter case, the bristle carrier is usually a thin plate made of thermoplastic material, which is provided with one or more openings for filling with one or more bristles or tufts of bristles. After filling and securing the bristles, the plate-like bristle carrier is then inserted into a prefabricated 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 made of prefabricated bristle carrier and molded-on residue.

[0005] CH 672 579 A5 proposes a method for securing bristle tufts in a bristle carrier using an anchor plate. This means that the bristle tuft is folded, and the anchor plate is located in the folding area, pressing into the wall of the anchoring opening and thus permanently fixing the bristle tuft to the bristle carrier. However, to more optimally close the opening on the front or front side of the bristle carrier, preventing bacteria and spores from settling and multiplying there, a bead on the bristle carrier, which runs around the anchoring opening and protrudes from the front side, is to be pressed inwards. The bristle tuft itself is not secured by this deformation of the bead, but by the anchor itself. The individual bristle tufts are hammered 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 heater on its front side, which is applied exclusively to the bead and causes it to melt or plasticize and then presses it radially inwards.

[0006] In addition to the aforementioned options for anchorless attachment of the bristle or bristle tufts to the bristle carrier, another method has emerged in theory, but has never been adopted in practice: the insertion of bristle tufts into a bristle carrier with openings that are preheated. After the bristle tufts are inserted into the soft bristle carrier, a press is used to apply pressure to the front side of the bristle carrier, from which the bristle tufts protrude, compressing the soft material around the edge of the openings and reducing the cross-section of the openings. Some concepts for this are presented below.

[0007] DE 198 53 030 A1 stipulates that bristle tufts have bristles fused together on their backs to form a thickened portion. The bristle carrier has openings into which, before the bristle tufts are inserted, cylindrical extensions of a heater are inserted without touching the edge of the opening. This radiant heat locally heats the inner edge of the openings. The bristle carrier is heated to a temperature that changes its structure, for example, the softening temperature, in the area of ​​the edge. The increase in temperature is intended to reduce the cross-section of the hole, so that the bristle tuft must penetrate the wall when inserted.After removing the heater, the bristle tufts are then pushed into the openings with their thickened ends. The thickened section is larger than the opening's cross-section, so that the thickened section penetrates the soft area of ​​the edge that defines and surrounds the opening, i.e., the corresponding wall. The front of the bristle holder is then deformed with a stamp, pressing the material of the bristle holder against the bristle tufts and anchoring them.

[0008] A similar method is known from US Pat. No. 5,224,763, in which the bristle carrier has a bead-like protruding opening edge. 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 is smaller in cross-section than the thickened end of the bristle tuft, so that the bristle tuft is fixed in place after being pushed 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, the dimensions and the temperatures being selected such that after the thickened end has been pushed in, the edge of the opening pushes 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 penetrating a plate-shaped plastic bristle carrier with a heated stamp equipped with pins, so that the pins form the openings for receiving the bristle tufts. The bristle tufts are then pressed into the embossed, still-hot openings, and the melt rises around the thickened portion of the bristle tufts. A mold plate can also be pressed against the upper side of the bristle carrier to further shape the melt. It is particularly preferred that projections or bulges protrude from the upper side of the as yet unformed bristle carrier, forming material that is available as material that is pressed toward the opening.

[0011] In the process according to DE 34 22 623 A1, a plate-shaped bristle carrier without openings is welded to bristle tufts made of the same plastic as the bristle carrier. A heating tool is inserted between the not yet welded sides of the bristle carrier and the bristle tufts, melting both. The bristle tufts are then pressed into the melted material of the bristle carrier. US Pat. No. 4,132,449 A proposes a very similar solution.

[0012] EP 2 078 472 A1 discloses a method for manufacturing toothbrushes, in which the bristles are pushed from the front through openings in the bristle carrier, so that they protrude from the back. This protruding part is then melted and reshaped to form a kind of film or plastic plate that merges integrally 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 a cover plate.

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

[0014] This object is achieved by a method for producing a brush which has a bristle carrier made of thermoplastic material with a front side and a back side and at least one anchoring opening into which at least one bristle made of thermoplastic material is inserted and anchored therein without an anchor, so that it protrudes from the front side of the bristle carrier, characterized by the following steps: the at least one bristle is received in a receiving opening of a tool part, the at least one bristle is pushed with its fastening end, while still sitting in the receiving opening, into an anchoring opening in the bristle carrier formed during the manufacture of the bristle carrier, the distance between the tool part and the bristle carrier is reduced so that the tool part contacts the bristle carrier, the front side of the bristle carrier is brought to a temperature that is below the melting temperature of the bristle material and / or the bristle carrier material, in particular at most 85% in °C of the respective melting temperature of the bristle and / or the bristle carrier material, the tool part exerts a compressive force on the heated bristle carrier and deforms the bristle carrier at least in the region of the edge surrounding the anchoring opening, reducing the cross-section of the anchoring opening in such a way thatthat the at least one bristle is embedded and anchored in the anchoring opening, and the distance between the tool part and the bristle carrier is increased so that the at least one bristle is pulled out of the receiving opening, wherein the application of the pressure force takes place in a device in which the bristle carrier is contacted at the front by a tool part and at the back by a holder, while the pressure force is exerted on the bristle carrier, wherein the device is moved to a block when the pressure force is applied so that the holder and the tool part around the bristle carrier (10) are in full contact with the front surface, and after an advancing movement of the tool part and the bristle carrier relative to one another, which movement is completed when the device reaches a closed position, the pressure force is exerted on the bristle carrier for a predetermined holding time in the closed position, wherein the holding time is at least 1 second.

[0015] The front of the bristle carrier is preferably heated by the tool part being heated. If, as is the case in the preferred variant, the front of the tool part contacts the front for a few seconds, the temperature of the front of the tool part also corresponds to the temperature on the front of the bristle carrier, so that the temperatures correspond. This means that the front of the tool part is brought to a temperature that is below the melting temperature of the bristle material and / or the bristle carrier material, in particular at most 85% in °C of the respective melting temperature of the bristle material and / or the bristle carrier material.

[0016] While the above process steps preferably occur in the order shown, this is not mandatory. For example, the front of the bristle carrier could be heated first and then the distance between the tool part and the bristle carrier could be reduced, or both steps could occur simultaneously or partially simultaneously.

[0017] The change in distance occurs through a relative movement of the tool part to the holding part, ie the tool part can be moved, for this purpose the holding part is stationary, or vice versa, or the tool part and holding part both move.

[0018] When reference is made below to "at least one bristle," this means that this refers to a single bristle seated in a receiving opening and an anchoring opening, bristles of a single bristle tuft seated in a receiving opening and an anchoring opening, as well as multiple bristle tufts seated in their receiving openings and anchoring openings. Thus, the invention is not limited to the anchoring of a single bristle or spaced-apart, single bristles. Even if the bristle tufts are mentioned in some places below for ease of reading, the invention is generally applicable to a bristle carrier with one or more individual bristles, as well as to a bristle carrier with one or more bristle tufts, or combinations thereof. This also applies to both the method claims and the substantive claims.

[0019] The bristle carrier with its anchoring hole is a prefabricated injection-molded part, making it very easy to manufacture and requiring no further processing. The anchoring holes are preferably created during the injection molding process.

[0020] The compressive force is applied in a device when the bristle carrier is contacted at the front by a tool part and at the back by a holder, while the compressive force is exerted on the bristle carrier. The device is moved to a block to apply the compressive force. This means there is no gap between the holder and the tool part, as they contact each other at the front. This contact preferably occurs over the entire surface and around the enclosed bristle carrier in a parting plane between the holder and the tool part. This seals off the cavity formed between the holder and the tool part for receiving the bristle carrier in the parting plane. Here, no material from the bristle carrier can migrate into a gap and then form a burr on the finished bristle carrier.

[0021] A further special feature of the invention is that after a feed movement of the tool part and bristle carrier relative to one another, which ends when the device reaches a closed position, the compressive force is exerted on the bristle carrier for a predetermined holding time in the closed position. Despite the effort to keep cycle times as short as possible, according to this special feature of the invention the device is not closed and immediately opened again, as is usually the case when pressing, forming or punching objects. The compressive force does not have to be constant during the holding time, because it depends on the resistance of the bristle carrier. As the deformation of the bristle carrier increases, the compressive force will therefore decrease. The holding time must be at least 1 second, preferably at least 1.5 seconds.

[0022] A maximum holding time of 3 seconds, and especially a maximum of 2.5 seconds, has proven optimal. No more is necessary.

[0023] Below, several improvements are described that constitute inventions in their own right, but which, when combined with one another, also represent optimizations. It should be emphasized that the device explained later can also be equipped with the features described in connection with the method, with only the control system being programmed accordingly.

[0024] Due to the heating, a holder which holds the bristle carrier may possibly heat up during operation, for example by radiation. Furthermore, the time for which compressive force is exerted on the bristle carrier may be so long that the bristle carrier is heated too strongly deeper and further away from the front, and thus also deforms in these deeper areas, as extensive tests have shown. To prevent this, according to a variant of the invention, the back of the bristle carrier is actively cooled while the compressive force is exerted on the bristle carrier. A separate cooling device, for example by liquid cooling, is therefore provided. This makes it possible to adjust the volume range of the bristle carrier in which a sufficiently high temperature prevails for deformation during the application of pressure within narrower limits.In addition, the cooling device creates a safety zone within the bristle carrier in which no deformation occurs.

[0025] During the application of the pressure force, the back of the bristle carrier is actively cooled. Preferably, the bristle carrier reaches a maximum temperature of 25 °C during the process.

[0026] The aforementioned holder, which exerts a counterforce on the back of the bristle holder and against which the bristle holder rests, is actively cooled, in particular via liquid cooling.

[0027] Cooling can occur not only on the back of the bristle holder, but optionally also on at least sections of the so-called side surface of the bristle holder. The side surface is the surface that connects the front and back of the bristle holder. Cooling prevents the side surface from being plastically deformed laterally and outwards when the bristle holder is squeezed between the front and back. For this purpose, the holder can, for example, have a receiving recess for the bristle holder, which is designed to complement the bristle holder and ensures that the back and side surface rest against the holder.

[0028] As has surprisingly been shown in tests, the stability and precision of the bristle carrier and the alignment of at least one bristle, in particular the bristles of a bristle tuft, can be increased if, after the so-called exposure time (time during which pressure is exerted on the bristle carrier between the front and back), the device is not immediately moved apart and the bristle carrier removed. Although this is very disadvantageous in terms of cycle time, a ventilation gap is created between the front and the tool part after the exposure time. This means that the tool part and the holder are slightly moved apart from each other. The device is not moved completely apart, nor is it brought into a position in which the bristle carrier is or could be removed.A resting phase is provided for the bristle carrier and its at least one bristle, preferably one or more bristle tufts, during which the ventilation gap in the device acts to cool the front surface. During this resting phase, the rear surface, depending on the shape of the holder, and possibly also the side surface, continues to contact the holder, which has a shape-stabilizing effect.

[0029] The specified rest period should last at least 1 second, and preferably at least 1.5 seconds. During this time, there should preferably be no further movement between the holder and the tool part. Alternatively, a slow opening movement can be performed.

[0030] It is particularly advantageous if at least one bristle, in particular the bristle tuft(s), remains in its associated receiving opening throughout this resting phase. The receiving opening keeps the bristle(s) of one or more bristle tufts in shape during the resting phase. This stabilizes the area around the anchoring opening. Internal stresses are evidently reduced.

[0031] The ventilation gap should have a height of at least 1 mm, measured in the direction of travel of the device (direction of movement between the holder and the tool part when the device is opened and closed).

[0032] As already mentioned, the ventilation gap can preferably be kept constant during the rest phase.

[0033] Optionally, cooling air can be blown to the front of the brush head through the ventilation gap. This shortens the rest period.

[0034] The front side of the bristle holder can be heated during the holding time, particularly during the entire holding time, but optionally also during the feed movement. Heating during the feed movement saves cycle time. The front side is already heated during the feed movement, for example, by radiation. As soon as the front side contacts the heated tool part, the front side and the bristle holder are heated and brought up to temperature during the subsequent closing of the device.

[0035] The application time of pressure on the bristle holder is determined by the sum of the holding time plus the period during the feed movement in which the front side is first contacted by the tool part and the back side by the holder, and compressed until the fully retracted position is reached. This application time should be at least 4 seconds, and in particular at least 5 seconds.

[0036] The maximum exposure time has proven to be 15 seconds, and in particular a maximum of 10 seconds as the limit.

[0037] The holding time is preferably shorter than the above-mentioned period during the retraction, during which the bristle carrier is compressed. This retraction and compression takes place at a very slow feed rate of the holder relative to the tool part. In particular, this period is at least 3, especially at least 4 seconds.

[0038] Tests have shown that the holding time is a maximum of 50%, in particular a maximum of 40% of the above-mentioned time period when moving together, during which the bristle carrier is compressed.

[0039] In order to reduce the cycle time, it can be useful to heat the front of the bristle holder by other means and not just by contact with the tool part. The bristle holder can be preheated. For example, the bristle holder, when already in the holder, could have warm air blown onto its front or be briefly exposed to a heat source (e.g. radiant heat) that is not the tool part. This can take place during the feed movement from tool part to holder or even before this feed movement. For example, the bristle holder could be heated during an adjustment movement of the holder / tool ​​part or before the tool part is moved laterally towards the holder. The subsequent heating time due to contact with the tool part can thus be reduced.

[0040] A further special feature of the invention is that the free end of at least one bristle is supported at the end face of the device. This support is intended to determine the axial position of the bristle or bristles of one or more bristle tufts within the same bristle tuft or of bristle tufts relative to one another. For example, with multiple bristle tufts, the brush should have a sawtooth shape at the ends of the bristle tufts when viewed from the side. Other options include a bristle tuft being sawtooth-shaped, tapered, or conical.

[0041] It would be expected that this support, which serves as a stop or shaping means, would also act during the application of the compressive force to the bristle carrier, in order to prevent any displacement of the bristle, bristles, or bristle tufts during this time. However, it has been found that it is advantageous to remove the support at least during the application of the compressive force to the bristle carrier, preferably before the compressive force is applied or during the feed movement of the device after contact has been made between the front and rear of the bristle carrier by the tool or holder. This means that the previously inserted support is removed at least during the final phase of the application of the compressive force, and optionally also during the entire time the compressive force is applied.The minimal pressure introduced into the bristles by the support, at least in the final phase or even the entire phase of the deformation process, can lead to deformation of the bristles or to the bristles being crooked or not aligned parallel to each other, even within a tuft of bristles.

[0042] In this context, it may be useful for the cross-section of the at least one bristle and the cross-section of the associated receiving opening in the tool part to be coordinated in such a way that the at least one bristle / at least one bristle tuft is clamped in the receiving opening and can be positioned axially by the clamping. If the bristle or bristles of a bristle tuft are therefore axially aligned, they are clamped in the receiving opening and thus axially positioned. Of course, this clamping is only minimal and generally allows displacement during the previously occurring axial positioning process. However, the weight of the bristle / bristle tuft or the inertia during the movement of the device does not cause any automatic, unintentional displacement of the bristle / bristle tuft in the receiving opening.

[0043] Similar to the practice of anchorless fastening, at least one bristle or the entire bristle tuft can be given a thickened fastening end by thermally forming the bristle material by heating it above its melting temperature. When using a bristle tuft, the bristles of the tuft are joined together by thermally forming. However, this does not also join adjacent bristle tufts; instead, each bristle tuft has its own thickened fastening end, which is inserted into the anchoring opening.

[0044] The invention not only allows bristle tufts to be secured in the anchoring opening by reshaping the edge of the opening, but also prefabricated so-called elastomeric cleaning elements (e.g., made of thermoplastics) that are several times thicker than normal filaments of bristle tufts. 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, curved, cross-shaped, or round (circular or oval) shapes, as well as corresponding ring shapes with central openings.

[0045] The at least one anchoring opening can be filled with a single, prefabricated bristle made of an elastomer material, in particular thermoplastic elastomer (TPE). This single bristle is anchored in the anchoring opening by deforming the bristle carrier.

[0046] Preferably, the singular, prefabricated bristle has a maximum wall thickness, measured in cross-section, of greater than 0.6 mm, in particular greater than 0.9 mm. For example, with a rectangular cross-sectional shape, the maximum wall thickness is measured in the longitudinal direction.

[0047] Optionally, the single, prefabricated bristle can have a thickened attachment end, which is pushed into the anchoring hole and encompassed by the reshaped edge of the anchoring hole of the bristle carrier. The thickened attachment end is created during the manufacture of the single bristle and not by pressing and elastically deforming the bristle by reshaping the edge of the anchoring hole. Alternatively, however, 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.

[0048] The thickened attachment end has, for example, the shape of a flat cylinder and / or the singular, prefabricated 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 singular, prefabricated bristle outside the anchoring opening. Preferably, the attachment end is even harder than the entire remainder of the singular, prefabricated bristle. The harder attachment end improves the fit of the bristle in the anchoring opening.

[0049] Typically, several anchoring openings are provided in the bristle carrier, with at least one, preferably several, anchoring openings being provided only with the singular, prefabricated bristle(s). At least one other, preferably the remaining, anchoring openings, however, are provided with prefabricated bristle tufts, so that the brush has a hybrid of conventional bristle tufts and thicker, elastomeric cleaning elements.

[0050] For example, when viewed from the side, the free end of the individual bristle extends at least to the free end of the bristle tuft, meaning it is no 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.

[0051] A further special feature of the invention is that, after deformation, the wall defining the anchoring opening in the bristle carrier only partially abuts the fastening end of the at least one bristle or at least an entire bristle tuft located in the anchoring opening. The fastening end can, for example, also be a thickened end or the thickened fastening end of a bristle tuft in which the bristles merge integrally into one another. It would be expected that the entire anchoring opening would abut the fastening end as tightly and gap-free as possible in order to prevent any movement of the bristle or the bristle tuft in any direction. The invention, however, takes a different approach. The fastening end is not completely compressed, but has certain free spaces within the anchoring opening.This allows the position of at least one bristle, but especially of the bristles within a bristle tuft, to be adjusted more precisely. For example, if the thickened end of a bristle tuft is completely compressed, the bristles will try to spread apart and will no longer be aligned parallel to each other.

[0052] For example, the deformation should only occur in the area of ​​the edge of the anchoring hole, i.e. in the area of ​​the wall section that lies in the area of ​​the mouth of the anchoring hole.

[0053] With respect to the finished brush, the wall of the anchoring hole does not clamp the attachment end of the bristle or of at least one entire bristle tuft and / or does not deform the attachment end over a depth of at least 0.8 mm. This area, in which no clamping and / or no deformation of the attachment end occurs, begins at the bottom of the anchoring hole and extends further over at least 0.8 mm toward the front of the bristle carrier.

[0054] There may even be an air gap between the wall and the at least one bristle / tuft of bristles, particularly in the area of ​​the floor or adjacent to the floor of the anchoring opening.

[0055] As previously mentioned, at least one bristle or at least one entire bristle tuft can have a thickened attachment end. The edge of the anchoring opening is deformed, i.e., the area of ​​the wall that lies in the area of ​​the mouth toward the front. In this area, the edge is narrowed so that the anchoring opening widens toward the floor and the thickened attachment end is gripped behind by the deformed edge in the extension direction, preventing the bristle / bristle tuft from being pulled out by the edge acting as a stop.

[0056] With regard to the previously mentioned accuracy of the alignment of the bristle or bristles of a bristle tuft, the thickened attachment end can only be clamped in the anchoring hole for a maximum of 50% of its total axial length, starting from its end closest to the front of the bristle carrier in the axial direction toward the rear. For example, if the attachment end is a sphere, as is typically created by fusing the bristle ends, then at most only the half of the sphere facing the front will be clamped in the anchoring hole.

[0057] The narrowed "neck" of the anchoring opening formed by the deformation near the mouth, i.e., the deformed edge of the anchoring opening that engages behind the thickened fastening end, can, for example, have an axial extension (axial in the context of the invention always means in the direction from the front to the back or from the back to the front) of 0.5-1.3 mm, in particular 0.6-0.9 mm. This is an extremely small height.

[0058] The brushes produced by the invention, particularly toothbrushes, can have a very thin thickness in the area of ​​the bristle carrier. While toothbrushes previously had a thickness of over 4 mm in the head area, the invention enables a thickness of less than 4 mm, with better holding forces for the bristles or bristle tufts than in the prior art. Furthermore, the invention makes it possible to position bristle tufts, even larger bristle tufts, very close to the edge of the front, which was previously impossible.

[0059] Bristle tufts can also be narrowed in cross-section by deforming the edge of the anchoring opening. This means that a bristle tuft is secured in the anchoring opening, and the edge of the anchoring opening is deformed in such a way that the edge compacts the bristle tuft in an area where the bristles lie next to each other. The area where the bristles lie next to each other preferably borders directly on the attachment end formed by the fused bristles. The bristle tuft thus has a smaller cross-section after the deformation and narrowing of the anchoring opening than it had previously after the bristle tuft was inserted into the anchoring opening.

[0060] Preferably, the bristle tuft is densified by at least 3%, in particular at least 5%. This densification is defined by the difference in the cross-section, or more precisely, the difference in the cross-sectional area, of the receiving opening in the tool part compared to the cross-section of the deformed anchoring opening in the region of the edge, i.e., the mouth of the anchoring opening toward the front.

[0061] However, the cross-section of toothbrushes, for example, is only reduced by a maximum of 0.4 mm.

[0062] Preferably, the anchoring opening, before being deformed, has a lateral oversize of less than 0.2 mm compared to the largest cross-section of the attachment end of the tuft / bristle, to allow the attachment end to be inserted into the anchoring opening without exerting force. After deformation, a positive fit is achieved by the narrowed edge of the anchoring opening, with the edge being only 0.1-0.3 mm narrower in cross-section than the largest cross-section of the attachment end. This minimal overhang is sufficient to achieve excellent pull-out values.

[0063] The invention also makes it possible to process bristle carriers with elastomers already injection-molded onto the back. The elastomer is therefore already injection-molded onto the back of the bristle carrier when the bristle / tuft of bristles is inserted into the anchoring opening at the front. The holder, in which the bristle carrier is held when the pressure force is applied, has a recess. This recess is designed to accommodate the bristle carrier on the back together with the elastomer. The recess can, in particular, be designed to complement the shape of the bristle carrier provided with the injection-molded coating. Since the elastomer in toothbrushes is usually designed as a tongue cleaner with protruding nubs, the holder has correspondingly complementary recesses for these nubs.

[0064] Preferably, however, the depth of the recess is designed such that its volume for accommodating the elastomer is smaller than the uncompressed volume of the elastomer. This ensures that the volume in the recess is adapted to the actual volume of the compressed elastomer when the compressive force is applied to deform the edge of the anchoring opening. Since the elastomer is softer than the bristle carrier, it is important to prevent the compressive force from becoming too low due to the interposed elastomer.

[0065] The counterforce applied by the holder during deformation can be transferred entirely to the front part of the bristle carrier via the elastomer. Therefore, direct contact between the back of the bristle carrier and the holder without the interposition of an elastomer is not necessary to transmit counterforces to the bristle carrier.

[0066] The aforementioned diverse options of the method according to the invention can include the following optimized steps: the tool part is heated so that the end face of the tool part opposite the bristle carrier is brought to a temperature below the melting temperature of the bristle material and / or the bristle carrier material, in particular below 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 so that the tool part contacts the bristle carrier and heats it.

[0067] According to a further aspect, the method according to the invention for producing a brush having 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, is further developed by the following steps: an end face of the tool part opposite the bristle carrier is brought to a predetermined temperature which lies in a range of 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 brings it to the predetermined temperature, but without melting the bristle carrier and the at least one bristle.

[0068] In all embodiments, the thermoplastic material is preferably selected from the group consisting of polyester, in particular polyethylene terephthalate (PET), preferably BR003, 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.

[0069] 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. For this purpose, 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.

[0070] Preferably, the predetermined temperature is in a range between 30 °C and 150 °C, particularly preferably between 60 °C and 140 °C, in particular between 90 and 130 °C or 100 and 115 °C.

[0071] The predetermined temperature is further preferably above the glass transition temperature of the thermoplastic. This ensures sufficient deformability of the thermoplastic.

[0072] The method according to the invention differs fundamentally from the prior art because, firstly, it exclusively provides for anchorless fastening of the bristle, bristle tuft, or bristle tufts. The anchoring opening itself is prefabricated, i.e., holes are not pressed into the bristle carrier using heated stamps; rather, the receiving openings are already created during injection molding of the bristle carrier. Furthermore, the receiving opening is not heated on the inside first, thereby softening the inside edge of the opening so that the bristle or bristle tuft is pressed into the soft wall of the receiving opening. Rather, the bristle or bristle tuft(s) is preferably pushed into the receiving opening first, and only then is the bristle carrier heated on its front side opposite the tool part, but without melting it.The process is carried out below the melting temperature of the bristle material and / or the bristle carrier material, with heating being achieved by the tool part in which the bristle or bristle tuft is located, and not by a separate heating tool, which must then be moved away again when 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 envisaged 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 have a high degree of inherent stability in order to be able to transmit the pressing force exerted on the bristle tuft.Only the pressing force exerted on the back of the bristle tuft and the inherent rigidity of the cold bristle tuft made 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 itself, rather than through contactless heating, as is predominantly common in the prior art. This allows for faster energy transfer, and also allows the device to be manufactured using fewer parts.

[0073] The bristle carrier is heated during the entire forming process to a temperature below the melting temperature, preferably to a temperature that is significantly below the melting temperature, for example at least 15% below the respective melting temperature calculated in ° C and preferably a maximum of 15% above the glass transition temperature, calculated in ° K and for a bristle carrier material with a glass transition temperature of greater than or equal to 300° K. 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 in ° K. The bristle carrier is preferably heated to a temperature above the glass transition temperature.

[0074] The invention and its advantageous variants described above and below particularly provide for the use of polypropylene as the bristle carrier material, some groups of which have a glass transition temperature of less than 300° K, while others have a glass transition temperature above 300° K. 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.

[0075] 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. The melting temperature 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.

[0076] To ensure relatively short cycle times during the production of bristle carriers, one embodiment of the invention provides for the tool part to be 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, since the bristle tuft was intended to press into the soft wall. According to the invention, the tool part can already be heated to its predetermined maximum operating temperature before it contacts the bristle carrier.

[0077] One embodiment of the invention provides, among other things, 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.

[0078] As already explained, the bristle carrier should only be heated after at least one bristle has been inserted through the tool part, preferably exclusively by contact. Of course, if a bristle carrier comes into proximity with a warm or hot tool part, a minimal temperature increase may occur, but this temperature increase is absolutely negligible and only occurs at the immediate surface.

[0079] However, if the feed motion takes a very long time, it is conceivable that the tool part brings the bristle carrier in the area of ​​contact with the tool to a temperature that is below the melting temperature of the bristle carrier material and, preferably, greater than or equal to the glass transition temperature of the bristle carrier material during the feed motion of the tool part. Alternatively or additionally, the bristle carrier can also be brought to the aforementioned temperature when the tool part contacts the bristle carrier.

[0080] According to one embodiment of the invention, the heating of the bristle carrier to the predetermined and previously mentioned temperature or temperature ranges 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 over a longer period of time, thereby heating it, the thermal energy also migrates deeper into the interior of the bristle carrier. This means that the bristle carrier does not have to be heated to its core when the tool part first contacts it; it is sufficient to achieve this heating during the feed movement and the exposure time (contact time).

[0081] In a first phase of the feed movement relative to the bristle carrier, the tool part 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 that is above a limit temperature which corresponds to 60% in °C, in particular 80% of the glass transition temperature of the bristle carrier material when working with a bristle carrier material with a glass transition temperature of greater than or equal to 300° K. This particularly applies to bristle carrier materials such as polypropylene variants with a glass transition temperature of greater than or equal to 300° K, PET, PBT, PA, ABS, SAN and PC. Alternatively, the limit temperature is the ambient temperature when working with a bristle carrier material whose glass transition temperature is 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.

[0082] The bristle carrier material can in particular be heated to a temperature that lies in a range between the glass transition temperature and below about 85% of the melting temperature of the thermoplastic, calculated in °C. Depending on the thermoplastic material used, this temperature is preferably in a range of between 30 °C and 210 °C, particularly preferably between 60 and 140 °C, preferably between 90 and 130 °C or 100 and 115 °C.

[0083] As tests have shown, the bristle or tuft of bristles should first be pushed into the receiving opening before the tool part contacts the bristle carrier, in particular before the bristle carrier has been heated to a temperature, at least in the area of ​​the edge surrounding the anchoring opening (preferably in the entire contact area), which is above a limit temperature which 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 greater than or equal to 300°K (this particularly applies to bristle carrier materials such as polypropylene variants with a glass transition temperature of greater than or equal to 300°K, 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.especially polypropylene variants with such low glass transition temperatures. The edge of the anchoring opening is at least the outer edge on the front side of the bristle carrier.

[0084] Another variant of the invention provides that the at least one bristle or tuft of bristles is first pushed into the receiving opening before the edge of the anchoring opening is heated to a temperature that is at least 30°C above the ambient temperature, 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 variant, the edge inside the opening is not noticeably heated, in contrast to the prior art, where heatable pins were supposed to penetrate the opening to heat the inside edge of the opening, i.e., the wall defining the opening, down to the hole base.

[0085] The deformation should be such that the edge of the bristle carrier, at the transition to the front or end of the bristle carrier, presses against the outer bristles of the attached bristle tuft along its entire circumference, thus compacting the bristle tuft. Of course, the type or extent of compaction depends on the cross-section of the bristle tuft. For toothbrushes, for example, the cross-section of the anchoring opening is reduced by a maximum of 0.3 mm, preferably by a maximum of 0.15 mm.

[0086] Preferably, the lack of heating of the opening wall also applies to the other embodiments. This means that, optionally, the edge is generally only brought to the specified limit temperature or temperatures in the area of ​​the front side, i.e., at the transition from the front side to the anchoring opening. However, the ambient temperature in the opening itself remains essentially constant as long as the tool part does not contact the bristle carrier.

[0087] A preferred embodiment of the invention provides that the tool part is heated in the entire contact area in which the tool part contacts the bristle carrier and not just in the point-like or linear area around the edge of the anchoring opening. This has the advantage that the tool part has the entire contact area and thus the entire adjacent material area of ​​the tool part at its disposal in order to move and reshape this material area through the high applied pressure. It is also advantageous if the tool part even contacts the entire end face of the bristle carrier facing the tool part, i.e. its front side, or at least contacts and applies pressure to at least 70% of the surface area of ​​the front side. In the prior art, protruding beads on the manufactured bristle carrier created a type of collar that represented the only heated and reshaped material.However, the present invention clearly differs from this in that precisely those sections of the bristle carrier which are located away from the front edge of the anchoring openings are heated and reshaped.

[0088] The back of the bristle carrier should not be heated by the tool part during anchoring, so only the front side, facing the tool part, is actually heated and reshaped, while the back forms a plate-like, stable structure that could be referred to as the base of the bristle carrier. Consequently, this part of the bristle carrier is not reshaped or changed in shape during pressure application.

[0089] The tool part can also heat the bristle carrier at the front end, at least for the entire time it exerts pressure on the bristle carrier. Therefore, the invention does not involve a brief preheating of the bristle carrier and a subsequent rapid movement of the bristle tufts into the heated material sections of the bristle carrier, as is the case in the prior art with preheated bristle carriers into which the bristle tufts are then pushed.

[0090] 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, in this case 300 °K, energy should be introduced into the bristle carrier via the tool part. This is also advantageous for materials whose glass transition temperature is below the ambient temperature. However, according to a variant of the invention, with such bristle carrier materials it is also possible to manage without heating the bristle carrier by the tool part. Then, at ambient temperature, the deformation is achieved exclusively by the pressure of the tool part on the bristle carrier.

[0091] Advantageously, bristle carrier materials are heated to the following temperatures in the method according to the invention and by the device according to the invention 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°

[0092] The invention provides, in particular for PET, heating of the front side of the bristle carrier in a range of 75-95 °C, in particular 80-90 °C, and for PP from 115 to 125 °C, in particular 110-120 °C.

[0093] In particular, PP with a melt flow index (MFI) of 6-35, preferably 10-15, is used.

[0094] In the preferred embodiment, the method according to the invention provides not just one bristle that is inserted into a receiving opening, but several anchoring openings and several receiving openings in the bristle carrier or in the tool part. The receiving openings are each aligned with the associated anchoring openings. Tufts of bristles are inserted into the receiving openings and then pushed into the anchoring openings, preferably pushed in 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 exerting pressure on the front side of the bristle carrier, the anchoring openings are closed simultaneously, thereby anchoring the tufts of bristles simultaneously.

[0095] Preferably, the contact area between the tool part and the bristle carrier on the tool part is flat, as is the front side of the bristle carrier, which faces the tool part.

[0096] The feed movement of the tool part relative to the bristle carrier can be pressure and time controlled and / or pressure and distance controlled.

[0097] Alternatively, the device is simply brought to a standstill, for example, by providing an electric motor (e.g., via a spindle drive). The current or power consumption of the electric motor is detected. Once a predetermined limit is reached, it is assumed that the device is in the closed position, in which the holder and the tool part are preferably in contact. From this point on, the so-called holding time could then begin.

[0098] The term "movement or feed movement of the tool part relative to the bristle carrier" means that one of the two parts or both parts are moved relative to each other.

[0099] A further variant of the invention provides that the tool part exerts a preferably constant compressive force on the bristle carrier for a predetermined time from the moment it comes into contact with the bristle carrier. This optional method is particularly easy to implement because a compressive force is simply applied and exerted on the bristle carrier for a certain period of time, as a so-called contact time, before the tool part and bristle carrier are subsequently separated again. As with the other variants of the invention, no further process steps are required here to anchor the bristle or tuft(s) of bristles in the bristle carrier.

[0100] The feed motion and / or the pressure applied by the tool part relative to or on the bristle carrier can vary nonlinearly over time from the moment the tool part contacts the bristle carrier until the maximum feed path is reached. This allows, for example, a longer or shorter initial exposure time to the temperature to be achieved, and then a different pressure is applied to further and permanently deform the bristle carrier material.

[0101] In contrast to the previously mentioned prior art, the fastening end of at least one bristle or of the entire bristle tuft can be smaller than the cross-section of the anchoring opening when inserted into the associated anchoring opening(s), of course before its deformation and before the bristle carrier is heated. This means that the bristle tuft is not pressed into the lateral wall of the anchoring opening, as was proposed in the prior art. The fastening end is also not pressed into the base of the anchoring opening, because this is not heated or not heated sufficiently to be soft. Furthermore, no axial force is exerted on the bristles that exceeds the force necessary to push the bristles out of the receiving opening.

[0102] Important for the present method and a major difference from the prior art is the relatively long exposure time of the tool part to the bristle carrier, during which pressure is exerted on the bristle carrier and the latter is additionally heated. The exposure time is at least 4 seconds, in particular at least 5 seconds, and a maximum of 15 seconds, in particular a maximum of 10 seconds. Over this long exposure time, the pressure can remain constant and / or a permanent heating of the bristle carrier can occur. The anchoring opening can be a blind hole, in particular with a maximum depth of 4 mm, more particularly a maximum of 2.7 mm.

[0103] By deforming the bristle carrier in the front area, the thickness of the bristle carrier is reduced by the method according to the invention.

[0104] The anchoring opening is only formed and narrowed to a depth of maximum 85%, in particular maximum 70%, preferably even maximum 60% of its total depth, i.e. it is not narrowed in the area of ​​the bottom of the blind hole.

[0105] Another significant difference from the state of the art is the applied pressure, which is considerably higher than in previously proposed methods. The tool part applies a pressure of at least 200 bar, in particular at least 400 bar, to the bristle carrier.

[0106] The at least one anchoring opening, preferably all anchoring openings, do not have a protruding collar in the area of ​​the mouth of the anchoring opening 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 area of ​​the surface or contact surface is reshaped and, with the exception of an inclined anchoring opening explained below, no protruding collar is necessary as a material accumulation.

[0107] If the anchoring opening has an internal edge section that runs diagonally relative to the front side opposite the tool part, additional material accumulation may be necessary in this area. In this case, the bristle carrier has an extension on the front edge in the area of ​​the diagonal edge section that protrudes from the front side toward the tool part. Otherwise, the front side of the bristle carrier is advantageously completely flat.

[0108] The tool component used is, in particular, a magazine that is loaded with at least one bristle or at least one bristle tuft. If multiple bristles or multiple bristle tufts are to be attached to the bristle carrier, all bristles or bristle tufts are housed in the same magazine and are inserted simultaneously after loading.

[0109] After loading, the fastening end(s) of the bristles or bristle tufts protrude from the magazine with their fastening end and are heated at this fastening end without having to leave the magazine. The thickening then forms at the fastening end protruding freely from the magazine. The magazine is therefore not just a stamping tool, but also a transport tool, which is moved laterally from a loading station to the bristle carrier and then pressed against the bristle carrier.

[0110] The thickened fastening end can then be actively cooled immediately after it has been created before it is inserted into the anchoring opening in the bristle carrier. This increases the cycle time. It also prevents the thickened portion from being deformed when the pressure is applied, resulting in the bristles no longer being optimally aligned. Active cooling does not mean that the thickened fastening end in the device is cooled by the ambient temperature prevailing there. Rather, a cooling device is provided, for example an active air flow generated by a fan. This air flow can either transport ambient air from, for example, further away from the heated parts, or it can transport cooled air from an air conditioning system.Another possibility is to provide a cold chamber through which the fastening end with the bristle(s) is transported.

[0111] 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 has been proposed in the prior art.

[0112] As has been shown, the position of the so-called parting plane between the holder and the tool part, in which the two abut one another, relative to the bristle carrier is important. It is therefore advantageous if the cavity created to accommodate the bristle carrier is not only formed in the holder, but also partly in the tool part. However, based on the thickness of the bristle carrier, the majority of the cavity is formed by a depression in the holder. The parting plane should preferably be close to or immediately adjacent to a rounded transition between the side surface and the front side of the bristle carrier, i.e. outside the rounded transition. This ensures that this rounded transition is under no circumstances provided with any kind of step or burr created by material pressed out of the bristle carrier.

[0113] By applying pressure and heat, or pressure alone, the overall thickness of the bristle carrier is permanently reduced—not just partially, but entirely. The end face of the tool part opposite the bristle carrier is heated to a maximum temperature of 140 °C, particularly 130 °C. Polypropylene, PET, ABS, or SAN are used as materials for the bristle carrier.

[0114] When using PET as bristle carrier material, it has been found that the front side of the bristle carrier should be heated to 75-95 °C, in particular 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, in particular 110-120 °C.

[0115] As briefly mentioned above, at least one elastic cleaning element made of an elastomer, in particular TPE, can be injection-molded onto the bristle carrier and attached to the bristle carrier before or after the attachment of at least one bristle. The cleaning element is arranged at the edge of the bristle carrier and / or inwardly of the edge between bristles or bristle tufts. Consequently, mixed forms of cleaning elements are conceivable in the same brush. Injection-molded cleaning elements, bristle tufts that are attached to the bristle carrier by reshaping the edge of the anchoring opening, as well as individual bristles in the form of elastomeric, prefabricated cleaning elements, which are also attached to the bristle carrier by reshaping 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.

[0116] The bristles can also be pre-sharpened, chemically or mechanically pre-sharpened bristles or pre-rounded.

[0117] Several bristle tufts can be anchored in the same bristle carrier, with at least one bristle tuft consisting of bristles made of a different material with a different melting temperature than the bristles of at least one other bristle tuft. The bristle tufts consisting of different bristle materials are heated to different intensities in order to fuse the bristles of a tuft together to form a thickened attachment end. This can be implemented in various ways: The distance between the end of the bristle tuft facing a heating device and the heating device is set differently depending on the bristle material and / or the heating device is heated to different temperatures depending on the bristle material and / or different heating devices heated to different temperatures, tailored to the assigned bristle material, are used.

[0118] For example, the bristle tufts are pushed out of the magazine to different distances. Those bristle tufts made of a more easily melting material, for example, remain closer to the magazine than the others, so that the further-extended bristle tufts are closer to the heating device than the others and are therefore heated more intensely. Alternatively, the bristle tufts can be processed one after the other by pushing the bristle tufts made of different bristle materials out of the magazine one after the other with their attachment ends, so that they are then moved closer to the heating device. Either the heating device is then heated to two suitable, different temperatures, or different heating devices are used for their respective assigned bristle tufts.

[0119] For example, with a brush with nylon and PBT bristles, the nylon bristles are heated first and then the PBT bristles.

[0120] The advantageous variants mentioned above can also be combined with each other as desired.

[0121] 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 a plurality of 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, for carrying out the method according to 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 heater which heats at least sections of the end face, which heater is designed and controlled such that the end face is heated to a temperature of maximum 140 °C, in particular maximum 130 °C,A control system is provided which is programmed so that the device carries out the method according to the invention. In particular, polypropylene, PET, ABS, or SAN are used as the material for the bristle carrier.

[0122] In the device according to the invention, a tool part, which acts as a temporary support for the bristle or tuft(s), is used as a pressing ram and, at the same time, as a transport means. A heater on the front side of the tool part is designed and controlled by a controller such that the front side is heated to a maximum temperature of 140°C, in particular a maximum temperature of 130°C, when it is moved against the bristle carrier. A device that can theoretically operate at higher temperatures, but whose control or regulation limits the temperature accordingly, naturally also falls under the device as defined.

[0123] As already explained above 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, wherein the feed movement can be pressure and time controlled and / or pressure and distance controlled or only time controlled or only distance controlled.

[0124] 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, that is to say in the direction of the holder.

[0125] The heating capability of the tool part should be implemented in the entire contact area with the bristle holder or even in the entire area of ​​the front side of the tool part which is opposite the holder and thus the bristle holder inserted into the holder.

[0126] As already explained in connection with the method according to the invention, the tool part is, for example, a magazine, which is loaded with the at least one bristle or the at least one bristle tuft in a loading station of the device. The at least one bristle or the at least one bristle tuft ("at least one bristle" generally includes, for the entire present description and the claims, also one or more bristle tufts) protrudes from the magazine with its fastening end after loading. In a melting station located downstream of the loading station, the fastening end(s) is / are heated, forming a thickened portion. When using one or more bristle tufts, the bristles of the corresponding bristle tuft are combined by thermal forming. In particular, a type of mushroom-, dome-, or spherical thickening is formed.

[0127] In general, with the device according to the invention, either the magazine can be moved and the stations remain stationary, or the magazine remains stationary and stuffing tools or heating devices or holders are moved to the magazine. These tools or holders can, for example, be arranged on a rotating carousel that moves through the stationed magazines one after the other. The device according to the invention has a controller that controls the feed movement of the tool part relative to the bristle holder and the heating process of the tool part such that the tool part is heated up before it comes into contact with the bristle holder. This means that before the tool part is fed towards the holder, the tool part is already warm. The maximum operating temperature can, but does not have to, be reached during this phase.The bristle carrier is only heated after the insertion of at least one bristle by the tool part, which is achieved by the projection of the thickened end relative to the magazine and the distance of the front side of the magazine to the corresponding contact surface on the bristle carrier.

[0128] The device according to the invention is particularly designed such that the tool part is permanently heated to the desired temperature required to heat the front side of the bristle carrier for the deformation process. This means that the tool part is already warm and at this desired temperature when the at least one bristle or the bristle tuft(s) are inserted into the receiving opening(s). If the tool part also receives the at least one bristle / bristle tuft when the bristle ends are melted to form the thickened fastening end, care must be taken to ensure that the temperature of the tool part and / or the residence 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.

[0129] The controller can heat the tool part to such a temperature and control the feed of the tool part to the bristle carrier in such a way that the tool part brings the bristle carrier in the region of the contact surface with the tool part during the feed movement of the tool part to the bristle carrier and / or when contacting the bristle carrier to a temperature which 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 controller is programmed in such a way 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 the temperature of the tool part to a maximum of 50% above the glass transition temperature in ° K.

[0130] Of course, the method or device according to the invention can be used with brush bodies or bristle carriers manufactured using standard single- or multi-component injection molding processes. For example, handles, or more generally, brush bodies or bristle carriers used in toothbrushes that are traditionally equipped with (metal) anchoring technology, can be used. However, these handles / brush bodies / bristle carriers typically have deeper anchoring openings than required for the method according to the invention.

[0131] Multi-component handles, brush bodies, or bristle carriers have also been available for years in anchor technology, with elastomeric structures molded into the head area of ​​the brush body between the anchoring holes and / or the edge of the brush head. Elastomeric tongue cleaners, for example, can also be attached and molded onto the back of the brush head. All of these possibilities also apply to the method and device according to the invention.

[0132] In the anchor technique, these elastomer structures are attached to the front or back of the toothbrush before the bristles are applied. Only in exceptional cases is the elastomer structure attached after the bristles have been applied, but this is not common. Typically, these elastomer structures are molded onto a stiffer support structure in a multi-component injection mold. Such multi-component molds for toothbrush bodies are very common.

[0133] The handles, brush bodies / bristle carriers supplied with the method and / or device according to the invention can be easily injection-molded using all currently known brush body injection-molding techniques and tools. The anchoring openings are pre-injected using mold pins, which can have round or any desired cross-sectional shape and which protrude 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 sliders, before complete demolding of the injection-molded part. The so-called mold pins can be mounted parallel and / or at an angle to one another in order to create parallel and / or angled anchoring openings in the injection-molded part.With the method and device according to the invention, pins can typically be immersed somewhat less deeply into the injection cavities when injection molding such parts than when injection molding brush bodies or bristle carriers that are to be plugged using the anchoring technique. Consequently, the anchoring openings in the injection molded lengths are somewhat shallower. Because these openings are shallower, the overall head thickness of brushes produced using the method and device according to the invention can be made significantly thinner than for brush heads plugged using the anchoring technique. This provides a clinical advantage in the manufacture of toothbrushes.

[0134] The method and device according to the invention have particular advantages when using clear materials for the bristle carrier or the brush body. Such materials are typically PET, copolyester, SAN, ABS, etc. These materials can also have pre-injected anchoring openings, as with polypropylene bristle carriers / brush bodies / handles, 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 the multi-component process, they can be further processed as described above and subsequently with reference to the device, as provided for by the invention.

[0135] An injection station for producing the tuft carrier can be provided upstream of the station with the holder and the tool part acting, for example, as a press ram. The injection station includes an injection mold half with at least one extension projecting into an injection cavity, which is immovably attached to the injection mold half or is an integral part thereof. This partially or even completely eliminates the active slides previously used in injection mold halves. Each extension creates an anchoring opening designed as a blind hole. Slides are not only complex to manufacture, but also expensive to maintain and repair.Since in the device according to the invention the bristle or bristle tufts are not fixed in the bristle carrier with an anchor, which requires a minimum depth for the anchoring opening, anchoring openings with a smaller depth are completely sufficient for fixing the bristle or bristle tufts.

[0136] The tool part is heatable, for example, by an integrated electrical resistance heater, and the holder is equipped with an active cooling device, in particular connected to a cooling water circuit. Thus, components that touch each other and define at least one common cavity for receiving a bristle carrier are heated and cooled simultaneously.

[0137] The device has at least one electric motor, preferably a servo motor, for applying the pressure force to the bristle carrier. Electric motors have the advantage that the pressure force can be adjusted very easily and that they are reliable and easy to adjust.

[0138] Multiple electric motors can be provided to apply the pressure force. Furthermore, one electric motor can also apply pressure to multiple bristle carriers simultaneously by defining multiple cavities between a tool part and a holder. To increase the ejection rate of the device, multiple electric motors are provided, each of which applies pressure to multiple bristle carriers.

[0139] Furthermore, the use of turntables or similar devices is useful to increase the output rate. For example, depending on which stations require a longer cycle time, multiple units can be provided.

[0140] The device according to the invention should have a control system programmed to ensure that the tool part is continuously heated to the desired temperature during operation when pressure is applied to the bristle carrier. Thus, no desired temperature fluctuations occur during operation, so there is no heating time for the tool part that would negatively impact the cycle rate.

[0141] A holder for the device according to the invention is provided with at least one cooling channel. Connections on the outside of the holder allow connection to a cooling circuit, in particular a liquid cooling circuit.

[0142] The holder is in particular a plate with one or more cavities for receiving the bristle carrier(s).

[0143] The holder preferably also has recesses for multiple bristle carriers to form partial cavities. Because the holder's recesses are precisely matched to the brush design (flat support), a new holder must be manufactured for each new design. This makes the holders extremely expensive. The cooling channels further increase the costs.

[0144] To keep costs low, it can be advantageous if the bracket has only one cooling channel on its back, which is groove-shaped in cross-section and can be created very easily by milling. The cooling channel is then completed by a flange plate on the fixture side, for example a permanently present one, which is also provided with a groove on its front. When the bracket is then screwed to the flange plate, the two grooves complement each other to form the closed cooling channel or channels. Alternatively, the cooling channels or the cooling channel can of course also be created by one or more holes drilled through the plate-like bracket. In order to connect the parallel holes, for example, at the edges, head plates can be provided, similar to those in a car radiator. These connect adjacent ends of cooling channels to one another in terms of flow.

[0145] The holder has a recess for each bristle holder that is shaped complementarily to the bristle holder, from which the bristle holder preferably protrudes slightly.

[0146] Furthermore, it is expressly pointed out that the advantages and features previously mentioned in connection with the method according to the invention are also applicable to the device according to the invention, individually or in combination, in accordance with the method according to the invention.

[0147] Furthermore, it should be emphasized that the method and device according to the invention can be used with any brush, not just toothbrushes. For example, the method and device can also be used for household brushes, scrubbers, household brooms, or any type of broom, dishwashing brushes, toilet brushes, hairbrushes, vacuum cleaner brushes, handwashing brushes, and brushes of any type, for example, for painting, painting, nail polish brushes, and facial brushes (as well as manual or electric toothbrushes). The details and variants described in the following drawings are therefore also applicable to all of these brushes.

[0148] Further features and advantages of the invention will become apparent from the following description and the following drawings, to which reference is made.

[0149] The drawings show: Figure 1a to 1gvarious successive steps of the method according to the invention in perspective top view and perspective bottom view, which also shows the device according to the invention, 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 Figures 1e and 1f shown anchoring station before the magazine and bristle carrier move towards each other, Figure 4 a corresponding view of the station after Figure 3 at first 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 feed movement and after the end of the exposure time, immediately before moving apart and opening the station, Figure 6 a sectional view through an alternative assembly station, Figure 7 a sectional view through the anchoring station according to Figure 3, in which diagonally directed tufts of bristles 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 in the present invention, Figure 10 a sectional view through an injection mold with which the bristle carrier is Figure 9 is injected, Figure 11 a 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 another variant of the device according to the invention, here the anchoring station, with the holder when used for a bristle carrier provided with an elastomer.

[0150] In Figure 1a device for producing brushes, for example toothbrushes, is shown. As is known, such a toothbrush has a brush head with tufts of bristles protruding from the front, a neck, and a handle. These three sections can merge into one another in one piece, forming the so-called brush body. The brush head can either be stuffed directly, or it can be made in two parts, with a plate-like bristle carrier which, after injection molding, already has prefabricated 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. An alternative to this is for the brush head to be made in one piece, so that it itself forms the bristle carrier.

[0151] Such an execution is in Figure 1As shown, the brush head also forms the bristle carrier 10. In this illustration, the bristle carrier 10 is also the brush body, as it includes the handle, neck, and head of the brush. The bristle carrier 10 is a prefabricated, injection-molded part. Figure 2 shows that the bristle carrier 10 has numerous prefabricated 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 readable to plate-like bristle carriers 10.

[0152] The Figure 1 The device shown comprises several stations, namely a loading station 14, which is located in the Figures 1a and 1b shown, a melting station 16, which is 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.

[0153] All stations are passed through a magazine 20, also called a tool part, which transports tufts of bristles through the individual stations.

[0154] Although in Figure 1 a magazine 20 is shown with receiving openings for a brush, which will be shown in more detail later, in practice the magazines 20 are preferably so large that several adjacent groups of receiving openings for several brushes are formed in the magazine 20. There may also be several rows of groups of receiving openings for several brushes.

[0155] The magazine 20 is, for example, a plate-shaped part with a constant thickness, which has a Figure 1 upper, flat front side 22. Alternatively, the magazine, which is essentially plate-shaped, has on its flat front side 22 a recess 200 with a bottom 202, which can also be flat, as shown in Figure 14to form part of a cavity for receiving the bristle carrier 10.

[0156] Since the magazine passes through several stations and is subsequently used to produce additional brushes, the device features a magazine circulation system, with numerous identically designed magazines 20 being cycled through the individual stations one after the other. 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 cycled around the magazine, for example, on a carousel. This allows several stationary magazines, or more precisely, the bristle tufts arranged in the magazines, to be processed simultaneously.

[0157] The magazine 20 has numerous receiving openings 26 which have a hole pattern that corresponds to the hole pattern of the bristle carrier 10.

[0158] Each bristle tuft 24 consists of several bristles, which are separated from a bristle supply and, as Figure 1a shown, 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 with compressed air or vacuum.

[0159] The bristles are made of a thermoplastic material, especially PA, PBT, polyester, copolyester, or polypropylene, but they can also be made of elastomers. Furthermore, it is also possible to use coextruded bristles, for example, with a PA core with an elastomer coating. As will be shown later with the Figures 11 and 12As will be explained later, it is not absolutely necessary that only bristle tufts 24 be inserted and embedded in the anchoring opening; rather, only a single, prefabricated bristle in the form of, for example, an elastomeric cleaning element can be inserted and fixed in its anchoring opening according to the method mentioned above and described below. Such cleaning elements are injection-molded or foamed separately and are softer than the bristle carrier 10.

[0160] The bristle tufts 24 have opposite ends and protrude with their rear ends 28, called fastening ends, slightly out of the magazine 20, thus they protrude slightly from the front side 22. This is in Figure 1b shown.

[0161] The magazine 20, which is completely equipped with the bristle tufts 24, is transported laterally into the melting station 16, as in Figure 1cshown. In this station, a heating device 30 is present, 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, so that the individual bristles exceed their melting temperature and the bristles of a tuft merge together to form a thickened fastening end. The bristles of a bristle tuft 24 are thus integrally connected to one another. The thickening 32 of a bristle tuft 24 does not merge into neighboring thickenings of the adjacent bristle tufts 24, but remains spherical or lens-shaped thickenings. Also, preferably, no stamp is pressed against the thickenings or the still liquid material of the molten bristle ends.

[0162] 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 temperature than the bristles of at least one other bristle tuft 24. The bristle tufts 24 consisting of different bristle materials are heated to different intensities in order to fuse the bristles of a tuft together to form a thickened fastening 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 set 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, tailored to the associated bristle material, are used.

[0163] For example, depending on the bristle material, the bristle tufts are pushed out of the magazine 20 to different distances. For example, those bristle tufts 24 made of more easily melting material remain closer to the magazine 20 than the others, so that the bristle tufts 24 that are pushed out further reach the heating device 30 than the others and are therefore heated more intensely.

[0164] Alternatively, the bristle tufts 24 can also be processed sequentially by pushing the bristle tufts 24, which have different bristle materials, out of the magazine one after the other with their fastening ends in order to then move closer to the heating device 30. Either the heating device 30 is then heated to two suitable, different temperatures, or differently heated heating devices 30 are used for their respective assigned bristle tufts.

[0165] The pushing out of individual or groups of bristle tufts is carried out, for example, with a divided base plate 44 (see Figure 5 ), the parts of which can be moved independently of each other in the longitudinal direction of the bristles.

[0166] For example, with a brush with nylon and PBT bristles, the nylon bristles are heated first and then the PBT bristles.

[0167] The thickened portions 32 can optionally be actively cooled in the melting station 16 or on the way to the subsequent anchoring station 18 or in the anchoring station 18. 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 is passed with the thickened portions 32 still soft on the back. By cooling the thickened portions 32, the cycle time can be increased.

[0168] 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 locked in the anchoring openings 12 of the bristle carrier 10 exclusively without anchors.

[0169] The anchoring station 18 comprises at least one holder 34 (preferably several holders 34) which, on its end face 36 opposite the end face 22 (see Figure 2 ) has a recess 38 (in the case of several bristle carriers 10 to be accommodated, several recesses), which is designed complementary to the corresponding shape of the bristle carrier 10, so that the latter rests flatly with its rear side on the holder 34 (see also Figure 14 ).

[0170] The holder 34 itself has a flat end face 36, opposite which, however, the bristle carrier 10 protrudes slightly, as Figure 2to protrude into the recess 200 in the magazine 20 complementary to the area of ​​the front side of the bristle carrier 10, as is shown for example in Figure 14 is shown.

[0171] The magazine 20 is heatable, for example either by an externally supplied plate heater, which is moved laterally to the magazine 20 in the anchoring station 18 and can heat it up quickly, since the magazine 20 is made of metal.

[0172] Alternatively, a heater, in particular an electrical resistance heater 39, is formed in the magazine 20, which Figure 2 and in Figure 14 is shown. The heating coils are symbolically indicated; they are located close to the end face 22 or, in the case of a recess 200, close to the bottom 202 of the recess 200, which represents part of the end face 22.

[0173] Electrical connection contacts 41, for example sliding contacts on a side surface of the magazine 20, make it possible to electrically couple the magazine 20 when the magazine 20 is moved into the anchoring station 18 in order to activate the heater 39. Of course, it is also conceivable that the front side 22, including the bottom 202 of the recess 200, itself represents an electrical resistance heating layer, so that the front side is heated directly here.

[0174] If the magazine 20 is fixed, the electrical connection for the heater is very easy to implement and can be permanent.

[0175] The heater 39 ensures that preferably the entire end face 22 that comes into contact with the bristle carrier 10 is heated, i.e. also the sections between the thickened portions 32.

[0176] The temperature to which the end face 22 (in the area of ​​contact with the bristle carrier 10) is brought is below the melting temperature of the bristle and / or bristle carrier material, preferably of both materials. In particular, it is at most 85%, calculated in °C, of ​​the respective melting temperature of these materials. For example, if both materials have a melting temperature of 100 °C, the temperature of the finally heated magazine 20 at the end face 22 is at most 85 °C.

[0177] Figure 3 shows a sectional view through the anchoring station 18 in Figure 1e before the magazine 20 and the bristle carrier 10 are moved towards each other.

[0178] The thickening 32 has a dimension, viewed in the longitudinal direction A (also called the axial direction or feed direction), such 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 the inner edge 40 of the anchoring opening 12 or contacting the edge 40. In particular, the cylindrical anchoring opening 12 at this point in time only has an oversize of a maximum of 0.2 mm, in particular a maximum of 0.15 mm, compared to the largest cross-section of the thickening 32 (fastening end).

[0179] The magazine 20 and / or the holder 34, which are heated permanently, i.e. during the entire operation, to the desired temperature, are moved relative to one another. In the present case, only the holder 34 with the bristle carrier 10 is moved, so that first the thickening 32 enters the anchoring opening 12 before the end face 22 contacts the facing flat end and front face 42 of the bristle carrier 10. During the feed movement, the bristle carrier 10 is hardly heated at all, as long as the bristle carrier 10 is not contacted by the magazine 20, since the feed movement takes place very quickly and there is no dwell time in the Figure 3 shown open position of the anchoring station 18 is present.

[0180] A base plate 44 (see Figure 3), on which all bristle tufts 24 rest with their front, frontal, free ends and which forms a support, can serve to align the bristle tufts 24 with one another at their front ends and, at the same time, to create a distance, if desired, between the thickened portion 32 and the front side 22. The base plate 44 serves as a support for the individual bristles and for the bristle tufts 24.

[0181] In Figure 4 it is shown that the end face 22 contacts the front face 42 of the bristle carrier 10 and thus heats the bristle carrier 10 over the entire contact surface between the two parts.

[0182] 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.

[0183] However, the movement of the holder 34 does not remain in the position of the first contact, which is in Figure 4is shown, because a very high pressure is applied to the bristle carrier 10 via the holder 34 and the magazine 20.

[0184] For example, as they move toward 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 first contact between the bristle carrier 10 and the magazine 20 and remains constant throughout the contact time.

[0185] 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.

[0186] The exposure time is made up of a holding time and a time period (called the compression time) during the feed movement, which begins when the front side 42 is contacted by the magazine 20 and, at the same time, the back side of the bristle carrier 10 is contacted by the holder 34. The compression time ends when the maximum 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 in which the feed movement is completed, i.e. the device is completely 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, in particular a maximum of 2.5 seconds.

[0187] During the compression time, the distance between the fixture 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 no more than 3 seconds.

[0188] During the exposure time, the magazine 20 preferably continues to be heated, although the large mass of the magazine 20 might also allow the heating to be stopped after the initial heating to operating temperature. Nevertheless, the bristle carrier 10 would continue to heat up during the exposure time.

[0189] The device is in particular moved to a block, ie the holder 34 contacts outside the cavity formed by the recess 38 and the depression 200 with a front side 36 (see Figure 14) the section of the end 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 an annular contact area.

[0190] Furthermore, preferably generally, and not only limited to the embodiment shown, no heating is present in the contact area between the holder 34 and the magazine 20, so that the heating is present and effective only in the area of ​​contact between the front side 42 and the magazine 20.

[0191] The parting plane between the holder 34 and the tool part (here magazine 20), which is defined by the end face 36, is preferably closer to the front side 42 than to the rear side of the bristle carrier 10. Specifically, the parting plane is located just or immediately adjacent to a rounded transition between the side surface 212 connecting the front side 42 and the rear side.

[0192] It is advantageous if the support in the form of the base plate 44 is removed at least during the last phase of applying the pressure force, i.e., at the end of the exposure time, and no longer contacts the bristles. This improves the alignment accuracy of the bristles both to each other and relative to the bristle carrier 10. Preferably, however, the base plate 44 is removed before the start of the holding time or even before the exposure time, as shown in the Figures 3-5 symbolically represented by the arrow Y. For example, the base plate 44 is only in station c) and if necessary d) according to Figure 1 used.

[0193] However, in order to be able to determine the axial position of the bristle tufts and the individual bristles during the entire exposure time, the cross-section of the receiving opening 26 and the cross-section of the bristle tuft 24 inserted therein are coordinated in such a way that the bristle tuft 24 is clamped in the receiving opening 26 and thus securely positioned axially. The bristle tuft 24 is not displaced by its own weight or by inertia during movement within the stations and from station to station.

[0194] In the example mentioned, the entire flat end face is heated, at least where contact with the magazine 20 is present on the front side 42 of the bristle carrier 10. If the magazine 20 has a recess 200, it is sufficient and advantageous if the heater is only installed 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. However, the temperatures that are set are intended to bring the front side 42 of the bristle carrier 10 to the desired temperature.

[0195] The temperature to which the bristle carrier is heated in the area of ​​the front side 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 thus corresponds to the aforementioned maximum operating temperature of the magazine 20 in the area of ​​the front side 22 or the base 202.

[0196] Alternatively, at least the edge 50 of the anchoring opening 12 in the region of the front side 42 can be heated, which forms the region of the wall of the anchoring opening 12 that borders the mouth to the front side 42.

[0197] The temperature to which the bristle carrier 10 is brought, at least in the region of the edge 50, and preferably in the entire contact area with the magazine, should not only be below or significantly below the melting temperature of the materials, but in a 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 side 42, at least in the region of the edge 50, only to a temperature that lies above a limit temperature, which is 60% in °C, 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 greater than or equal to 300°K. However, this limit temperature is preferably 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.

[0198] A further 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 region of the front side 42, is heated to a temperature which 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.

[0199] 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 side 22 or a flat bottom 202 in the region of the front side 42.

[0200] Since the front side 42 is also flat and there is no collar or the like in the area of ​​the mouth 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 side 42 is deformed over its entire surface during the application of pressure and temperature. The material tries to escape and thus migrates into the anchoring openings 12 in the area of ​​the mouth, constricting them.

[0201] By applying heat and pressure, the total thickness D and thus the maximum thickness of the bristle carrier 10 is permanently reduced in the area of ​​the opening of the anchoring opening 12 to the front side 42. This creates a type of constriction that engages behind the thickened fastening end in the extension direction and thus secures the bristle tuft 24.

[0202] There is no adhesion between the thickened fastening end and the wall of the anchoring opening 12.

[0203] The deformation of the edge does not have to be extreme. It has been found that, for example, in the case of toothbrushes, it is sufficient to keep the cross-section of the anchoring opening 12 at the original width or the original diameter D3 in the area of ​​the edge 218 (see Figure 5A ) only to a width or an inner diameter D1 such 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 region of the edge 218 is only approximately 0.1-0.5 mm.

[0204] It is advantageous if the thickening 32 has an undersize compared to the still undeformed anchoring opening 12 during insertion (ie D2 is smaller than D3).

[0205] 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 on one side when it is inserted into the anchoring opening 12. In this context, it may be advisable for the material of the thickening not to have solidified all the way 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 on the inside, the skin, including the interior of the thickening, will simply deflect inwards without the thickening itself being damaged.It is still suitable to be circumferentially closed and gripped by the deformed edge.

[0206] By this idea of ​​inserting the thickening 32 into the anchoring opening 12 in a not yet completely solidified state, it is also possible to generally use a thickening 32 which is designed with an excess compared to the cross section of the anchoring opening 12, ie D2 greater than or equal to D3.

[0207] 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, just as the thickening 32 is exaggerated in relation to the diameter D1.

[0208] However, the fact is that not the entire wall forming the anchoring opening 12 rests against the thickening 32 or the outer bristles extending from the thickening 32. Rather, the wall is only deformed in the region of the edge 218 and in a directly adjacent section 220 that widens outward toward the base 208, and only in these areas does it rest against the bristles or the thickening 32 and exert pressure on them.

[0209] However, the thickening should contact the base 208 in order to precisely determine the axial position of the bristle tuft.

[0210] In the remaining area, for example between the base 208 and the thickening 32 or in the area of ​​the circumference of the wall adjacent to the base 208, there are one or more air gaps 222 between the wall and the outside of the thickening 32, so that the thickening 32 is not compressed, jammed and / or deformed in this area.

[0211] In the region of the edge 218, the bristle tuft 24 is compacted by at least 3%, in particular at least 5%, compared to its state in the magazine 20 by narrowing and constricting the edge 218. 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.

[0212] All anchoring openings 12 are closed simultaneously by the device shown and the corresponding method, and thus all bristle tufts 24 are anchored in the bristle carrier 10 at the same time.

[0213] As further stated in Figures 4 and 5A As can be seen, not the entire anchoring opening is formed, 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 extension of 0.5-1.3 mm, in particular 0.6-0.9 mm.

[0214] 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 remaining clamping occurs in the area of ​​the bristles extending from the thickening 32.

[0215] The wall of the anchoring hole 12 is drilled over a depth Z (see Figure 5A ) of at least 0.8 mm, starting from the bottom 208, the thickening 32 and also the bristles in this area are not deformed and / or jammed.

[0216] The depth T of the anchoring hole after manufacture of the brush is a maximum of 4 mm, in particular a maximum of 2.7 mm.

[0217] All anchoring openings 12 are blind holes, so that the bristle carrier 10 does not have to be covered on the back, since no parts of the bristle tufts are visible or protrude on this side.

[0218] The anchorage created in this way is the only anchorage for the bristle carriers; no metal anchor or metal wire is necessary.

[0219] It should be emphasized in general, and this applies not only to the illustrated embodiments, that the bristle carrier 10 should not be brought close to its melting temperature, but rather significantly away from this, close to the glass transition temperature. In particular, the heating temperature and thus also the temperature at the magazine 20 in the region of the end face 22 and the bristle carrier 10 at the end face should not be higher than 15% above the glass transition temperature of the bristle carrier material and / or the bristle material.

[0220] When using PET, according to a preferred variant of the invention, the front side 42 is heated during forming to a temperature of 75-95 °C, in particular 80-90 °C, and when using PP to a temperature of 105-125 °C, in particular 110-120 °C. The PP is in particular selected so that it has a melt flow index (MFI) of 6-35, preferably 10-15 in the initial state.

[0221] One embodiment of the invention provides that the end face 22 and thus the bristle carrier 10 are heated to a temperature of maximum 140 °C, in particular maximum 130 °C, preferably in the range of 100 to 115 °C. Polypropylene, PET, ABS, copolyester, and SAN are used as materials for the bristle carrier.

[0222] The rear side 206 of the bristle carrier 10 and the area extending from the rear side 206 to at least the bottom 208 of the anchoring openings 12 (preferably even further toward the front side 42) should not be deformed. In order 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 provided with active cooling.

[0223] 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, in particular even below 10°C, through the holder 34. The rear side 206 thus reaches a maximum temperature of 25°C during the application of the compressive force. The side surface 212 connecting the front side 42 and the rear side 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 and deformation would take place.

[0224] After the specified exposure time, the holder 34 and the 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 a different shape for the bristle carrier 10 is required.

[0225] However, the separation is preferably not carried out in one piece, but rather a rest phase is built into the separation process. For this purpose, the tool part, i.e., magazine 20, and holder 34 are minimally separated from each other, so that a small ventilation gap 228 (see Figure 5A) of greater than or equal to 0.5 mm. When the height of this predetermined ventilation gap 228 is reached, the distance preferably remains constant for the rest phase, which is at least 1 second, in particular at least 1.5 seconds.

[0226] Optionally, during this rest phase, cooling air can also be blown to the front of the bristle carrier 10 via the ventilation gap 228 in order to cool the front.

[0227] During this resting phase, however, the bristles remain in the receiving opening 26, as Figure 5A 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 evenly aligned.

[0228] After the resting phase, the device is moved apart so that the finished bristle carrier can be removed.

[0229] To precisely control the corresponding movements and temperatures, the device has a controller 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 controller 51.

[0230] If the bristle carrier material is a material such as certain types of polypropylene, for which the glass transition temperature does not exceed ambient temperature, then heating of the bristle carrier may be omitted, although this is not necessarily the case. Even here, minimal heating just above the glass transition temperature can be advantageous, but again significantly below the melting temperature. If heating is not necessary or required for such bristle carrier materials, the anchoring openings 12 are closed solely by applying the aforementioned pressure for the aforementioned exposure time. It is possible to use magazines 20 without heating or the same magazines with heating, whereby the heating is simply not activated.

[0231] Regardless of the bristle carrier material, the following applies: During the feed 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 towards the other part), a pressure and time-controlled feed movement and / or a pressure and distance-controlled feed movement can be advantageous.

[0232] In particular, it is advantageous if, in a first phase of the feed movement, the edge 50 or the entire front side 42 is heated to a temperature above a threshold temperature. This threshold temperature is 60%, 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 threshold temperature is at a glass transition temperature, at most up to 20% above the glass transition temperature in °C. In a subsequent second phase of the feed movement, the edge 50 is then deformed and pressed against the bristles.

[0233] Alternatively, the feed 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 moved onto one another in a block manner.

[0234] Also in the Figure 5 In the embodiment shown, in the closed state, 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.

[0235] The magazine 20 can be loaded either as shown in Figure 1a directly via a bristle separator, or via another variant that is Figure 6 Here, 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.

[0236] Alternatively, a deflection plate 64 can be provided between the cassette 60 and the magazine 20, which has inclined transport openings 66 for bristle tufts 24 moved through it. It is also possible to use converging transport openings 66, as in Figure 6shown on the left, to combine several bristle tufts 24 into one larger bristle tuft, for example, if the brush is to contain bristle tufts of different thicknesses. Furthermore, the magazine can of course also have obliquely running receiving openings 26, because there are brushes in which the bristle tufts do not run perpendicular to the front side 42, but are arranged obliquely to it. Here too, however, the anchoring is as shown in the figures. Alternatively, the anchoring openings 12 for such obliquely directed bristle tufts 24 can of course also be designed slightly obliquely or conical or conical only in the area of ​​the side of the bristle tuft 24 inclined towards them, as is the case in Figure 7 is shown.

[0237] In Figure 8An anchoring opening is shown, which has an edge portion 80 extending obliquely to its front side 42 opposite the tool part. Before the tool part acts on the bristle carrier, the bristle carrier has, on the front edge 50 in the region of the obliquely extending edge portion 80, an extension 82 protruding from the front side 42 in the direction of the tool part, and otherwise a flat front side 42.

[0238] The bristle carrier 10 in the Figures 9 and 10is produced in an injection molding station belonging to the device according to the invention, in an injection mold having injection mold halves 100 and 102. This injection molding station is located upstream of the previously described station for stuffing the bristle carrier 10. These injection mold halves 100 and 102 form a cavity 104 between them, into which liquid plastic is injected to produce the bristle carrier 10. While in previously used injection molding stations, the injection mold half 100 was provided with pin-shaped, active slides that protruded through the injection mold half 100 into the cavity 104 and were withdrawn before the injection mold was opened, this variant provides a much simpler solution. Here, one or more extensions 106 are immovably attached to the injection mold half 100, which freely protrude into the cavity 104. These extensions 106 then create the anchoring openings 12.The depth of the anchoring openings 12 is significantly smaller than in previously manufactured bristle carriers that were stuffed using anchor technology. Alternatively, the bottom 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 molded anchoring openings 12, thus simplifying the subsequent removal of the bristle carriers 10.

[0239] Figure 9shows various variants of how the bristle carrier 10 can be designed. Not only circular or oval anchoring openings 12 can be provided, but any desired shape can be designed. For example, elongated openings, X-shaped, C-shaped, or any other shaped anchoring openings are possible. These large anchoring openings are equipped with bristle tufts composed of several individual bristle tufts, which are joined by melting their ends to form a large bristle tuft. Such large bristle tufts result in a corresponding wall-shaped bristle structure.

[0240] It should be emphasized that the device according to the invention and the method according to the invention can be used not only with several bristle tufts, but also with only one bristle tuft, for example to produce a brush and to fix only one or only individual bristles in a bristle carrier.

[0241] The anchoring openings 12 therefore generally do not have to serve only to receive and secure tufts of bristles; rather, prefabricated, singular bristles of any shape made from any elastomeric plastics can be received and secured exactly as previously described in connection with tufts of bristles. 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 into the C-shaped anchoring opening 12 as a singular bristle. In addition, 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 individual or several bristle tufts 24.

[0242] It should be emphasized that the aforementioned features, which were explained with reference to the bristle tufts, can also be used for individual, large bristles. Just one example is a plate-shaped bristle running diagonally to the bristle carrier 10, which is inserted into the inclined anchoring opening 12 in the Figures 7 and 8 and anchored therein. However, the singular bristle can also have an anchoring end 32 from which the elongated remainder protrudes at an angle, so that it fits into a cylindrical anchoring opening 12 according to Figure 4 can be inserted, whereby the bristle outside the anchoring opening 12 runs diagonally.

[0243] The singular, separately manufactured bristle 24' or bristles 24' is / 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, consecutive forming processes for the different bristles or bristle tufts. In this case, different pressures and / or temperatures can also be applied by the heated tool part(s) if necessary, because the bristles or bristle tufts are made of different materials.

[0244] In addition or as an alternative to the above variants, elastomeric cleaning elements 108 can be molded, for example, onto the edge of the bristle carrier 10. These cleaning elements 108 are not prefabricated, but they also protrude from the front of the bristle carrier 10 and serve to massage the gums.

[0245] For this purpose, the bristle carrier 10 can, for example, have holes on the edge or only recesses on the edge 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.

[0246] In the latter case, it is advisable for the cleaning elements 108 to merge integrally into the rear layer of softer plastic. As can be seen from the upper half in Figure 9 , which shows a variant of the lower half, this rear layer 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.

[0247] Another variant consists in that the bristle carrier 10, here the head of the toothbrush, is coupled to the neck of the brush body via a hinge 110 made of softer plastic.

[0248] Generally speaking, for all variants, the bristle carrier can be a small plate as part of the final brush body or the entire brush body. For example, the bristle carrier can also be a multi-component injection-molded part, which then 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, which then forms the bristle carrier, and then subsequently overmold this bristle-covered bristle carrier.

[0249] Accordingly, the spraying station can also be designed as a multi-component spraying station, or several spraying stations can be provided, between which the station in which the bristles are anchored is located.

[0250] The cleaning elements 108 and / or the singular, prefabricated bristles made of elastomeric material, which can be of any cross-sectional shape, preferably extend forward at least as far as the bristle tufts, but they can also extend beyond them or be shorter than them.

[0251] In Figure 11 It is shown that not only, as previously explained, are bristle tufts 24 with their thickened portion 32 at the fastening end inserted into the anchoring opening 12 and anchored therein by reshaping the edge, but that singular, prefabricated bristles 24' (of any shape seen both in side view and in cross-section) can be embedded in the bristle carrier without anchoring using the aforementioned method and device. The bristles 24' are injection-molded from an elastomeric material, in particular TPE.

[0252] The bristles 24' have, in their section protruding from the bristle carrier 10, a greatest wall thickness d (measured in cross section) which is greater than 0.6 mm, in particular greater than 0.9 mm.

[0253] Furthermore, the prefabricated bristles 24' can or should have a thickened fastening end 32' whose height is less than the depth of the associated anchoring openings 12, so that the inwardly formed edge engages around the fastening ends 32' to achieve a positive fit. The fastening ends 32' are, for example, flat cylinders whose shape is adapted to the shape of the anchoring opening 12. However, the outer dimensions of the respective fastening end 32' are matched to the cross-section of the anchoring opening 12 such that, upon insertion, a lateral gap exists between the fastening end 32' and the wall of the anchoring opening 12 before the deformation takes place.

[0254] 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 a attachment end 32' made of polypropylene. Also, only a core of the bristle 24' can be made of a harder material, which is then subsequently overmolded with a softer material. Thus, a disk made of a harder material would be conceivable, forming all or part of the core of the attachment end 32'.

[0255] Likewise, according to Figure 12 on the left, the disc 112 forming the core has an extension 114 formed integrally thereon, which projects into the part of the bristle 24' that will lie outside the bristle carrier 10.

[0256] The 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 molded onto it.

[0257] The Figure 12The singular bristles 24' shown are pointed, which is not to be understood as limiting.

[0258] In a toothbrush, for example, elastomeric areas are often sprayed onto the back of the bristle carrier, which are wider than the rest of the bristle carrier 10, and which serve as tongue cleaners, as shown in Figure 15 is shown. The elastomer 232 may have knobs or ribs. The recess 38 in the holder 34 is formed in the area of ​​the outer surface of the elastomer 232 complementary to the shape of the elastomer 232 in the uncompressed state. However, the volume that is available to the elastomer 232 for the compressed state (closed state of the device, see Figure 15) is less than in the unloaded state. This means that the height allowed to the elastomer 232 is reduced to the compression under the desired pressure. Optionally, during deformation, even the entire counterpressure can be introduced via the elastomer 232 from the holder 34 into the bristle carrier 10.

[0259] In Figure 13 A complete device with various stations is shown. It should be emphasized that the device according to the invention does not have to have all of the stations explained below.

[0260] In particular, all variants and details explained with reference to the previous figures, in particular with reference to Figure 1 , can also be implemented individually or in combination in this embodiment, regardless of whether this is, for example, cooling, ventilation, etc., as well as the previously mentioned temperatures, temperature ranges or times and the materials used.

[0261] 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 sharpened, are removed in tufts by a tuft separator 122.

[0262] These bristle tufts 24 are transported via a transport device to a station B, in which the bristle tufts 24 are then, if necessary, converted into the final tuft geometry and into the hole pattern of the subsequent brush.

[0263] 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 pushed, possibly by means of a pusher 126, into a further plate 128, which may contain forming or deflection openings 130 or openings 132 for combining several bristle tufts 24 into a common larger bristle tuft or for orienting bristle tufts 24 at an angle.

[0264] The bristle tufts 24 are then pushed further into the magazine 20. The hole geometry of the subsequent brush is then preferably realized in the magazine 20, although this is not necessarily the case, as will be explained later.

[0265] 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.

[0266] The transport of the bristle tufts 24 after separation can be carried out mechanically via sliders or the Figure 2 shown plunger 126 into the first intermediate magazine 124 and / or the magazine 20 in station B. In station A, as a further alternative, the second image from the left shows that the isolated tufts of bristles are conveyed into the intermediate magazine 124 or the magazine 20 via tubes or hoses 134 in which an overpressure or a vacuum is applied.

[0267] Regardless of which transport means is used for the bristle tufts, they can be fed and / or inserted into the magazine 20 individually, one after the other, in groups, or all at the same time.

[0268] A third alternative in station A shows a wound strand 136 made of parallel filaments. The strand 136 is wound onto a reel 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 off, cut-to-length bristle tufts 24 are created. For example, using a movable XY table, the spool or the end of the strand held in a movable guide is then moved 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 one after the other. Furthermore, multiple spools and strands can also be moved relative to the magazine 20 / intermediate magazine 124.The completely filled 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 pushers 126 press the bristle tufts 24 into the magazine 20.

[0269] In order to save the XY table, strands can also be transported from several rolls 138 simultaneously into the individual openings in the magazine 20 or the intermediate magazine 124 and then cut off.

[0270] Station C is a so-called profiling station. Here, the bristle tufts 24 are axially displaced so that the subsequent ends of the tufts used for brushing lie in a plane or, more generally, end in a predetermined, arbitrary surface.

[0271] In the illustrated embodiment, a wave shape is predetermined, which is why a stop plate 140 with a complementary wave shape is spaced from the magazine 20. The bristle tufts 24 are then pressed downward by a pressure plate 142, which preferably has a shape complementary to the surface of the stop plate 140, until all tuft ends rest against the stop plate 140.

[0272] However, station C may also be omitted if the desired profile can already be achieved in station B by suitable rams 126 of different lengths or of the same length. The two variants can also be combined by performing a so-called pre-profiling in station B by rams 126 of different lengths and then a fine profiling in station C by the stop plate 140.

[0273] 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 to varying degrees from the rear of the magazine 20, are cut off mechanically using a knife 144 or thermally using a hot wire 146 relatively close to the magazine 20. If necessary, when using a mechanical knife 144, the magazine 20 can also act as a counter knife. In this case, the bristle tufts 24 are pushed out slightly from the rear of the magazine 20 after cutting so that they protrude slightly beyond the magazine.

[0274] If necessary, station D can be omitted if the tuft ends already protrude evenly far to the rear of the magazine 20 after station B or C. This is particularly the case if the front tuft ends are to end in one plane.

[0275] The protruding portion 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 of the magazine 20. This also allows the geometry of the tuft end to be adjusted.

[0276] The fusion can be achieved by a heated stamp 148, which can touch the tuft ends or remain spaced from them, so that the filaments melt through radiant heat (particularly via infrared light). Alternatively, fusion can also be achieved with hot air. It is important that only a single, dedicated thickening is created for each tuft of bristles formed, because only those filaments that are to be later fixed in the same anchoring opening should be connected to each other by fusion. If necessary, the thickenings 32 can be cooled here, as previously explained.

[0277] In the subsequent station F, the bristle tufts are pushed, with their thickened fastening ends first, into the anchoring openings 12 of the bristle carrier 10 and pressed therein, as previously explained in detail. This insertion can occur simultaneously, sequentially, or in groups.

[0278] Another alternative is to provide a deflection plate with corresponding channels into which the bristle tufts 24 are inserted with their thickened fastening ends first, and then pushed further into the anchoring openings of the bristle carrier. This variant is useful when the final hole pattern of the brush or the alignment of the bristle tufts 24 has not yet been fully realized in the magazine.

[0279] The previously mentioned separately manufactured, singular bristles 24' can be fed into any station, either to the magazine 20 or first to the bristle carrier 10.

[0280] The pressure force is transmitted, for example, via at least one drive, e.g. an electric motor 240 (see Figure 1f ) is preferably applied to the holder 34, optionally with the interposition of a gear such as a spindle nut 242. This naturally applies to all embodiments.

[0281] The electric motor is in particular a servo motor.

[0282] 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.

[0283] In order to increase the output of finished brushes, several drives are provided, in particular next to one another, which in turn drive several holders 34, which in turn accommodate several bristle carriers 10.

[0284] The controller 51 is programmed accordingly so that the aforementioned method is carried out in the device.

[0285] The device and method according to the invention allow extremely long and thin bristle tufts to be anchored in the bristle carrier. The invention provides bristle carriers with bristle tufts with a length of more than 8 mm and a width of less than 2 mm, in particular less than 1 mm.

[0286] With such large edge lengths, the corresponding edges of the anchoring holes do not necessarily need to be shaped inward by the same distance. It has been found that it is sufficient to provide several overhanging edge sections that are shaped further inward toward the anchoring hole, alternating with edge sections that are shaped less inward.

Claims

1. A method of producing a brush which comprises a bristle carrier (10) made from a thermoplastic resin having a front side (42) and a back side (206) and 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, so that it protrudes from the front side (42) of the bristle carrier (10), 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), the distance of the tool part to the bristle carrier (10) is reduced, so that the tool part contacts the bristle carrier (10), the front side of the bristle carrier (10) is brought to a temperature that is below the melting temperature of the bristle material and / or the bristle carrier material, in particular that is a maximum of 85% in °C of the respective melting temperature of the bristle material and / or the bristle carrier material, the tool part applies a pressure force to the heated bristle carrier (10) and reshapes the bristle carrier (10) at least in the area of the edge surrounding 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 distance of the tool part to the bristle carrier (10) is increased, so that the at least one bristle is pulled out of the receiving opening (26), wherein the application of the pressure force is carried out in an apparatus in which the bristle carrier (10) is contacted on its front side by a tool part and on its back side by a holder (34), while the pressure force is applied to the bristle carrier (10), wherein the apparatus is moved to stop during application of the pressure force, so that the front faces of the holder (34) and of the tool part are in full surface contact around the bristle carrier (10), and after a feed motion of the tool part and the bristle carrier (10) relative to each other, which is completed upon reaching a closed position of the apparatus, the pressure force is applied to the bristle carrier (10) in the closed position during a predetermined dwell time, wherein the dwell time is at least 1 second.

2. The method according to claim 1, characterized in that the back side of the bristle carrier is actively cooled while the pressure force is applied to the bristle carrier.

3. The method according to claim 1 or 2, characterized in that after an application time of the pressure, the tool part and the holder (34) are removed from each other in such a way that a ventilation gap (228) is created between the front side (42) and the tool part, and that the unit made up of the bristle carrier (10) and at least one bristle remains in the apparatus for a predetermined rest period, in particular that the predetermined rest period is at least 1 second, in particular at least 1.5 seconds.

4. The method according to any of the preceding claims, characterized in that the dwell time is at least 1.5 seconds, and / or 3 seconds at the maximum, in particular 2.5 seconds at the maximum.

5. The method according to any of the preceding claims, characterized in that the cross-section of the at least one bristle and the cross-section of the associated receiving opening (26) are adapted to each other such that the at least one bristle is clamped in the receiving opening (26) and is configured to be positioned axially by means of the clamping.

6. The method according to any of the preceding claims, characterized in that after reshaping, the wall defining the anchoring opening (12) in the bristle carrier (10) abuts only in sections on the fastening end of the at least one bristle or of at least one complete bristle tuft (24), the fastening end being located in the anchoring opening (12).

7. The method according to any of the preceding claims, characterized in that the at least one bristle or the at least one complete bristle tuft (20) has a thickened fastening end (32'), and the edge (50) of the anchoring opening (12) is reshaped and the anchoring opening (12) is constricted in the region of its mouth such that the anchoring opening (12) widens towards the bottom and the reshaped edge (50) engages behind the thickened fastening end (32') in the pull-out direction.

8. The method according to any of the preceding claims, characterized in that a bristle tuft (24) is fastened in the anchoring opening (12) and the edge of the anchoring opening (12) is reshaped such that the edge compacts the bristle tuft (32') in a region in which the bristles are arranged next to one another, so that the bristle tuft (24) has a smaller cross-section than after insertion of the bristle tuft (24) into the anchoring opening (12) and before reshaping.

9. The method according to any of the preceding claims, characterized in that the application of the pressure force is carried out in an apparatus in which the bristle carrier (10) is contacted on its front side by a tool part and on its back side by a holder (34), while the pressure force is applied to the bristle carrier (10), in that the back side of the bristle carrier (10) is formed by an elastomer injection-moulded thereon, and in that the holder has a recess for receiving the bristle carrier (10) provided with the overmould, wherein the recess is formed in particular so as to be complementary to the shape of the bristle carrier (10) provided with the overmould.

10. The method according to any of the preceding claims, <b>characterized by the following steps: 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 is a maximum of 85% in °C of the respective melting temperature of the bristle material and / or the bristle carrier material, and the tool part is moved relative to the bristle carrier (10), so that the tool part contacts the bristle carrier (10) and heats it, or characterized by the following steps: a front face (22) of the tool part opposite the bristle carrier (10) is brought to a predetermined temperature which is in a range between ambient temperature and 210°C, preferably 150°C, and the tool part is moved relative to the bristle carrier (10), so that the tool part contacts the bristle carrier (10) and heats it, but without melting the bristle carrier (10) and the at least one bristle.

11. 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 loading, the at least one bristle or the at least one bristle tuft (24) protrudes from the magazine (20) by its fastening end (34') and the fastening end is heated, forming a thickening in the process, in particular in that the thickening is subsequently actively cooled before the fastening end is inserted into the anchoring opening (12), in particular by an active air flow or a cold chamber.

12. An apparatus for producing a brush which includes at least one bristle or at least one bristle tuft and which includes a bristle carrier having at least one anchoring opening for the at least one bristle or the at least one bristle tuft, for carrying out the method according to any of the preceding claims, characterized in that the apparatus has a holder for the bristle carrier and a tool part having at least one receiving opening for the at least one bristle or the at least one bristle tuft, wherein the receiving opening ends on the front face (22) of the tool part facing the bristle carrier (10), and in that the tool part includes a heating which heats at least portions of the front face (22) and which is adapted and controlled such that the front face (22) is heated to a temperature of 140°C at the maximum, in particular 130°C at the maximum, wherein a controller (51) is provided, which is programmed in such a way that the apparatus carries out the method according to any of the preceding claims.

13. The apparatus for producing a brush according to claim 12, characterized in that the apparatus has a tool part having at least one receiving opening for at least one bristle or at least one bristle tuft and has an opposite holder, wherein the tool part and the holder are movable towards each other and away from each other, and wherein the tool part is heatable and the holder is provided with an active cooling device.