EP3599933A1

EP3599933A1 - Method, device and injection moulding half mould part for producing a brush

Info

Publication number: EP3599933A1
Application number: EP18718102.9A
Authority: EP
Inventors: Bart Gerard Boucherie
Original assignee: GB Boucherie NV
Current assignee: GB Boucherie NV
Priority date: 2017-03-27
Filing date: 2018-03-27
Publication date: 2020-02-05
Anticipated expiration: 2038-03-27
Also published as: BE1024476B1; CN110545694B; WO2018177592A1; TW201838545A; CN110545694A; TWI751315B; EP3599933B1

Abstract

The invention relates to a method or a device for securing bristles in a bristle carrier (10) without anchors, in which once the bristles have been inserted into anchoring openings (12) in the bristle carrier (10), these openings are closed by the application of pressure and heat. A transition edge (320) surrounding the anchoring opening (12) has a chamfered edge (322).

Description

Method and device as well as injection mold half part for making a brush

The invention relates to a method and a device as well as an injection mold half for producing a brush, which has a bristle carrier made of thermoplastic material with at least one anchoring opening into which at least one bristle is inserted and anchored therein.

In the manufacture of brushes, in particular toothbrushes, but also household brushes, two methods have become established in practice, namely the fixing of the bristle tufts by means of an anchor (metal plate or wire loop) or anchorless. The anchorless method, in contrast to the use of an anchor before that the bristle tufts is not folded and fastened at its fold in the bristle carrier, but at one end to the bristle carrier by gluing or thermally locked. A common, enforced in practice method provides that the bristle carrier has openings through which the bristle tufts are inserted. With their back end, the bristle tufts protrude from the openings and are heated on the back of the bristle carrier. The thermoplastic material of the bristles melts with it, whereby the bristles materially merge into each other and a thickening results, by means of which pulling out of the individual bristles forward impossible. Usually, the numerous bristle tufts are liquefied on the back by means of hot air or a hot stamp, so that the material of the individual bristle tufts merges into one another and at the back results in a kind of layer of liquefied bristle ends. Subsequently, this back is covered, in particular overmolded.

A disadvantage of this solution is that a considerable procedural and device-related overhead must be operated due to this back-side necessary cover. It should be noted that just at Toothbrushes, the transition surfaces between adjacent layers are carried out as possible gap-free in order to avoid hygiene problems.

The term "bristle carrier" is understood to mean that part of the finished brush which carries the bristle or the tufts of bristles The bristle carrier can be the entire brush body, ie the integrally molded part of stem, neck and head, or even just a toothbrush In the latter case, the bristle carrier is usually a thin sheet of thermoplastic material provided with one or more openings for filling with one or more bristles or tufts of bristles, after filling and securing the bristles becomes the platelike bristle carrier then either inserted into a prefabricated brush body having, for example, a corresponding recess for the plate-like bristle carrier Alternatively, this is the usual case, the plate-like bristle carrier is encapsulated and thus results in a brush body prefabricated bristle carrier and molded remainder.

CH 672 579 A5 proposes a method for fixing bristle tufts in a bristle carrier by means of an anchor plate. This means that the bristle tufts are folded, and in the folding area is the anchor plate, which presses into the wall of the anchoring opening and thus permanently fixes the bristle tufts on the bristle carrier. However, so that the opening on the front or front of the bristle carrier is closed optimally, so that no bacteria and spores can settle here and multiply, a bead on the bristle carrier, which rotates about the anchoring opening and projects from the front side, to be pressed inwards. The bristle tuft itself, however, is not secured by this reshaping of the bead, but by the anchor itself. The individual bristle tufts are successively hammered into the bristle carrier via a tamping tool which pushes the folded bristle tuft through a tube. The tube itself then has on its front side a heater that rests exclusively on the bead and this brings to melting or plasticized and then pushes radially inward.

In addition to the above-mentioned possibilities for anchorless attachment of the bristle or bristle tufts on bristle carrier in theory, yet another method has been found, but which never prevail in practice could, namely the impingement of bristle tufts in a bristle carrier, which has openings and is preheated. After the bristle tufts have been pushed into the soft bristle carrier, the bristle carrier is pressurized on its front side, from which the tufts protrude, by means of a press, so that the soft material is compressed around the edge of the openings and the openings are reduced in cross section. In the following some concepts are presented.

DE 198 53 030 A1 provides that bristle tufts on their rear side have fused bristles to a thickening. The bristle carrier has openings into which cylindrical projections of a heater are inserted before the tufts of bristles are tapped, without touching the edge of the opening. Due to this radiant heat, the inside edge of the openings is heated locally. The bristle carrier is brought in the region of the edge to a joint-changing temperature, for example, the softening temperature. Due to the increase in temperature, the hole should be reduced in its cross-section, so that the bristle tufts must penetrate into the wall upon impact. After removing the heater, the bristle tufts are then pushed with the thickened end into the openings, wherein the thickening in cross-section is greater than the opening cross-section, so that the thickening in the soft region of the opening defining and surrounding edge, ie in the corresponding wall penetrates. Subsequently, the front of the bristle carrier is deformed with a stamp, so that the material of the bristle carrier is pressed against the bristle tufts and anchor them. From US 5,224,763 a similar method is known in which the bristle carrier has a bead-like protruding opening edge. Again, the edge of the opening is heated by a pin-shaped heating element projects into the opening or worked with hot air. The opening itself is smaller in cross-section than the thickened end of the bristle tufts, so that it is fixed therein after being pushed into the wall of the soft opening. The bristle tuft holder then compresses the heated circumferential bead so that additional material is available to close the opening at the transition to the face of the bristle carrier. From EP 0 355 412 A1 a method is known in which the thickened end of the bristle tufts and / or the edge of the opening in the bristle carrier are heated, wherein the dimensions and the temperatures are chosen so that after the abutment of the thickened end of the edge the opening inward urges and so, similar to a snap connection, the thickened end includes and receives it form-fitting.

EP 0 472 857 B1 proposes penetrating into a plate-shaped bristle carrier made of plastic with a heated punch, which has 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 thickening of the bristle tufts around. A mold plate may also be pressed against the top of the bristle carrier to still form the melt. In this case, it is particularly preferred that projections or beads protrude on the upper side of the not yet formed bristle carrier, which form material which is available as material which is pressed in the direction of the opening.

In the method according to DE 34 22 623 A1, a bristle carrier, which is designed plate-shaped and without openings, welded to bristle tufts, which consist of the same plastic as the bristle carrier. A heating tool is moved between the not yet welded together sides of the bristle carrier and the tufts of bristles, so that both are melted. Subsequently, the bristle tufts are pressed into the molten material of the bristle carrier.

However, the present invention relates to another method which is described in DE 10 2015 1 1 1 312 A1. Here, the bristle or bristle tufts is pushed ahead with a usually thickened attachment end in the anchoring opening. Subsequently, the bristle carrier is deformed under application of pressure and heat at the edge of the anchoring opening and narrowed. In this case, the bristle carrier is heated only in the region of the front, to a relatively low temperature, without reaching the melting temperature. The migrating through temperature and pressure material closes the anchoring opening only front side, so that extraction of the bristle or bristle tufts is no longer possible. The Material migrates to the outside of the singular bristle or the outside bristles of a bristle tufts. For the production of a bristle with high pull-out forces, therefore, sufficient material must be available to largely close the anchoring opening to the front. For this reason, there are bristle carriers in which in the region of the front edge an anchoring opening protrude one or more integrally formed during injection molding of the bristle carrier projections or projections. These extensions form additional material which is first contacted by the tool and then moves inwardly to close the anchoring aperture. Another advantage of these extensions is that the pressure applied for forming pressure can be relatively low and that the actual thickness of the bristle carrier (measured without the extensions) is not or hardly reduced during forming. This means that the setting must be less precise when the tool is moved in and when it is being pressed. Important for high-quality brushes, especially toothbrushes, is that not too much material is available during pressing, which is then pressed into the receiving openings for the bristle or the bristle tufts in the tool. This additional material would then like a thin, nonspecifically shaped collar on the singular bristle or on the outside of the bristle tuft and protrude from the front.

The object of the invention is to improve the known method so and accordingly to provide a device for carrying out this method by which such collars are avoided.

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 rear side and at least one anchoring opening into which at least one bristle made of thermoplastic material having a thickened attachment end is inserted and anchored therein in an anchorless manner, so that it protrudes from the front side of the bristle carrier, wherein the at least one anchoring opening is defined by an inner side and has on the front side an edge surrounding the anchoring opening, characterized by the following steps: a) the bristle carrier is provided, which has a transition edge to the inside in the region of the front edge, which is chamfered at least in sections over the circumference of the transition edge, wherein the anchoring opening and the transition edge are produced during injection molding of the bristle carrier,

b) the at least one bristle is received in the receiving opening of a tool part,

c) the at least one bristle is pushed with its thickened attachment end, while it still sits in the receiving opening, in the anchoring opening formed in the bristle carrier during the production of the bristle carrier,

d) the distance of the tool part to the bristle carrier is reduced, so that the tool part contacts the bristle carrier,

e) the front side of the bristle carrier is brought to a temperature which is below the melting temperature of the bristle material and / or the bristle carrier material, in particular not more than 85% in ° C of the respective melting temperature of the bristle and / or bristle carrier material,

f) the tool part exerts a compressive force on the heated bristle carrier and deforms the bristle carrier at least in the region surrounding the anchoring opening frontal edge while reducing the cross section of the anchoring opening such that the at least one bristle is embedded and anchored in the anchoring opening, wherein thereby material of Borstenträgers in the region of the edge and the inside is pressed laterally into the anchoring opening and in the region of the transition edge and presses against the at least one bristle, and

g) the distance of the tool part to the bristle carrier is increased so that the at least one bristle is pulled out of the receiving opening.

The heating of the bristle carrier can be done before or during the reduction of the distance of the tool part to the bristle carrier or after the first contact of the tool with the bristle carrier. Thus, the order of steps d) and e) is not necessarily sequential. The invention is based on the idea that the material which closes the anchoring opening to the front and secures the bristle or bristle tufts against being pulled out is provided exclusively by the brush body between the front and rear sides and thus without an integrally formed extension, the bevel provides at the transition edge for a kind of buffer space, in which the material can penetrate, without protruding as a collar opposite the end face formed by the front. In the area of the chamfer, therefore, less material is available to be pushed inwards, so that material could be pushed axially from an area deeper into the anchoring opening to the outside. Contrary to the prior art which provided additional material, the present invention provides a deliberate material reduction at the transitional edge. Although so that the bristle carrier must be pressed together exactly, by the reduction in material and thus gained space at the mouth of the anchoring opening but larger tolerances when moving the tool are possible as without these bevels.

The chamfer may extend along the entire periphery of the transition edge and optionally along the entire circumference of the transition edge having the same cross-section, that is the same shape and have the same dimensions, which is optimal for the production of the injection molding tool.

Alternatively, however, the chamfer may also have different cross-sections along the circumference of the transition edge, which can be optimized so that the material is pressed in different sections to different degrees inward and therefore requires more or less buffer space.

For example, the bevel along the circumference of the transition edge have different cross-sections, but begin in the same axial depth of the anchoring opening. The axial depth is measured from the bevel adjacent front of the bristle carrier. Generally, this is not limited only to this embodiment, the front has a flat, convex or concave shape. In a convex or concave shape, the depth is measured from the front envelope.

As has been found in practice, bevels are sufficient to begin in the anchoring opening at a depth of at least 0.1 mm and a maximum of 0.5 mm, in particular a maximum of 0.35 mm, away from the adjacent to the bevel front of the bristle carrier ,

The bevels require only a radial width of at least 0, 1 mm and a maximum of 0.5 mm, in particular a maximum of 0.35 mm,

In cross section, the chamfer may be formed in sections by a chamfer and / or a bow, in particular a radius. These simple geometries facilitate the manufacture of the injection molding tool and on the other hand, as has been found in experiments, are absolutely sufficient to prevent expulsion of material from the anchoring opening.

As previously explained, the front of the carrier may be a flat, a convex or a concave curved surface.

In particular, a plurality of anchoring openings are provided, wherein at least some anchoring openings each have a bevel and the bevels of anchoring openings are different. Also by this method it is ensured that the anchoring opening are considered individually and are tailor made, on the one hand to achieve a high pull-out strength and on the other hand, an optimal appearance of the brush.

In the method according to the invention, the at least one anchoring opening of the bristle carrier is not completely compressed, but only in the area of the mouth, that is to say in the area of the front edge which surrounds the anchoring opening. In this case, the at least one anchoring opening of the bristle carrier is reduced only to a maximum of the beginning of the thickened attachment end of the bristle or bristle tufts, in particular only to a depth of at most 1 mm in cross section. The remaining part of the anchoring opening remains in its original shape. The bristle carrier is compressed so that material of the bristle carrier in

Area of the edge and the inside of the anchoring opening laterally in the Anchoring opening is pressed into and in the region of the transition edge without projecting beyond the envelope formed by the front of the bristle carrier to the outside.

The chamfer also forms no chamfer, because a chamfer is completely unnecessary at this point, in particular, this is the case when the thickened attachment end has a rounded or bevelled bottom, with the advance of the bristle or bristle tufts is inserted into the anchoring opening. This rounded or beveled underside is usually produced upon fusing the bristles of a bristle tuft. A bristle tuft is inserted with its thickened attachment end ahead in the anchoring opening, that the thickened attachment end does not contact the chamfer of the anchoring opening.

The lateral dimensions of the thickened attachment end are in particular smaller than the lateral dimensions of the respective associated anchoring opening in the region of the bottom of the anchoring opening. Thus, a lateral clearance is present, which allows a quick insertion of the bristle or bristle tufts in the anchoring opening. Moreover, the shape of the bristle or bristle tuft is not affected, as might be the case if the bristle were the bristle tufts compressed and compressed at their "root", that is, at the thickened attachment end Bristle or the parallel alignment of the bristles of a bristle tuft safer.

In contrast to the prior art, the brush body is sprayed together with the at least one anchoring opening, ie the anchoring opening is not produced by impressing a hot stamp. The inside of the anchoring opening is provided with a so-called Entformungsschräge, which may be, for example, a maximum of 2 °. As a result of this draft, demolding of the bristle body from the injection mold is facilitated and in some cases only possible. However, this draft is not part of the bevel and does not belong to this. Individual bristle tufts or all bristle tufts can be used perpendicular to the adjacent front and embedded in its anchoring opening.

Alternatively, there are bristles or bristle tufts, which are inserted obliquely to the front in the anchoring opening. The invention provides in this case that the bevel is formed larger at the transition edge on the side inclined to the bristle or bristle tufts than at the remaining circumference of the transition edge. Alternatively, there may be no chamfer at all on the side remote from the bristle or bristle tufts and a chamfer in the remaining part of the circumference of the transitional edge. Since less material has to be reshaped in the area of the front edge of the anchoring opening due to the inclined position of the bristle tuft on the side to which the bristles incline, there is an increased risk that material will migrate out of the anchoring opening. Therefore, in this area, an additional or a larger buffer space is required by the bevel.

The back side of the bristle carrier should be actively cooled while the compressive force is applied to the bristle carrier to keep the backside stable and allow no deformation in the area of the backside while compressing the bristle carrier.

The bristle carrier usually has a plurality of anchoring openings. An embodiment of the invention provides that none of the edges of the anchoring opening is provided with a projection which projects in front of the bristle carrier. Of course, alternatively, especially where anchoring openings are particularly close to each other and only a thin web is present, sections such projections may be provided.

Preferably, in the method according to the invention, the front side of the bristle carrier is heated. In this case, the front side is brought to a temperature which 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 correspondingly heated bristle carrier according to feature e).

The heating of the bristle carrier on the front side is preferably carried out by the tool part, which is heated. If, as in the preferred variant of the case, the front side of the tool part contacts the front side for a few seconds, the temperature of the front side of the tool part also corresponds to the temperature on the front side of the bristle carrier, so that the temperatures correspond. This means that the end face of the tool part is brought to a temperature which 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 bristle carrier material.

Although the above process steps are preferably carried out in the above order, this is not absolutely necessary. For example, the front side of the bristle carrier could also be heated first and then the distance of the tool part from the bristle carrier could be reduced, or both steps could be simultaneous or partly simultaneous.

The change in distance is effected by a relative movement of the tool part to the holding part, i. the tool part can be moved, this is the holding part silent, or vice versa, or tool part and holding part both move.

When hereinafter referred to as "at least one bristle", this means that both a single bristle sitting in a receiving opening and an anchoring opening, bristles of a single bristle tufts sitting in a receiving opening and an anchoring opening, as well as a plurality of bristle tufts, The invention is not limited to the anchoring of a singular bristle or spaced-apart, singular bristles, and although the bristle tufts are further mentioned below in some places for ease of reading, the invention is It can also be used in general for a bristle carrier with one or more individual bristles as well as for a bristle carrier with one or more bristle tufts or combinations thereof, in addition to both the method claims and the claims in kind. In the following, several improvements, which represent inventions themselves, are described, which however also represent optimizations in combination with each other. It should be emphasized that the device explained later can also be provided with the features described in connection with the method, with only the controller being programmed accordingly.

Due to the heating may possibly be a holder which receives the bristle carrier, are heated in operation, for example by radiation. Furthermore, the time in which compressive force is exerted on the bristle carrier can be so long that the bristle carrier is heated to a greater depth and farther from the front side too much, and thus also deformed in these deeper regions, as extensive experiments have shown. To prevent this, according to a variant of the invention, the rear side of the bristle carrier, while the compressive force is exerted on the bristle carrier actively cooled. It is therefore a separate cooling device, for example, by a liquid cooling, provided. Thus, the volume range of the bristle carrier, in which there is a sufficiently high temperature for forming during the application of pressure, within narrow limits adjustable. In addition, a safety zone is created within the bristle carrier by the cooling device, in which no deformation takes place.

During the application of the compressive force, the back of the bristle carrier is actively cooled. Preferably, this ensures that the bristle carrier becomes a maximum of 25 ° C in the process.

The already mentioned holder, via which a counter force is exerted on the bristle carrier at the rear and bears against the bristle carrier, is actively cooled, in particular via liquid cooling.

The cooling can be done not only on the back of the bristle carrier, but optionally also at least at portions of the so-called side surface of the bristle carrier. The side surface is the surface that connects the front and the back of the bristle carrier. By cooling is excluded that the side surface, when the bristle carrier is squeezed between the front and back, laterally outwardly plastically deformed. For this purpose, for example, the holder a Have receiving recess for the bristle carrier, which is complementary to the bristle carrier and ensures an investment of the back and the side surface of the holder.

The bristle carrier is preferably heated only after the introduction of the at least one bristle by the heatable tool part.

The tool part can be heated by an integrated electrical resistance heater or by a heated neighboring part, which outside of the bristle carrier contacting contact surface temporarily contacts the tool part and transfers the heat to the tool part in this contacting. The controlled heating of the tool part to a predetermined temperature is not effected by a "random" heating of adjacent, more or less hot parts, but via a heater assigned only to the tool part. 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 pressing force is exerted on the bristle carrier. In particular, the device for applying the pressure force is moved to block. This means that there is no distance between the holder and the tool part, because they contact each other at the front. Preferably, this contact takes place over the entire surface and around the enclosed bristle carrier in a parting plane between the holder and the tool part. Thus, the cavity, which is formed between the holder and the tool part for receiving the bristle carrier, sealed in the parting plane. Here, no material of the bristle carrier can migrate into a gap, to then form a burr on the finished bristle carrier. As has surprisingly been found in tests, the stability and accuracy of the bristle carrier and the orientation of the 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 the pressure on the bristle carrier between the front and Rear is applied) the device is not immediately disassembled and the bristle carrier is removed. Although this is very disadvantageous in terms of cycle time, a ventilation gap is created after the contact time between the front and the tool part. This means that the tool part and holder are slightly removed from each other. It will The device has not moved completely apart also not brought into a position in which the bristle carrier is removed or could be removed. It is a rest phase for the bristle carrier together with its at least one bristle, preferably one or more bristle tufts interposed, in which the ventilation gap acts in the device for cooling the front. Depending on the shape of the holder, the rear side also contacts the holder in this quiescent phase, depending on the shape of the holder, which has the effect of stabilizing the shape.

The predetermined rest phase should last at least 1 second, in particular at least 1.5 seconds. Preferably, no further movement takes place during this time between the holder and the tool part. Alternatively, a slow opening movement can take place.

It is particularly advantageous if the at least one bristle, in particular the bristle tuft, remains or remains in its assigned receiving opening during this entire resting phase. The receiving opening holds the bristle or bristles of one or more bristle tufts during the resting phase in the form. This stabilizes the area around the anchoring opening. Obviously, internal stresses are reduced. The ventilation gap should have a height of at least 1 mm, which is measured in the direction of travel of the device (direction of movement between the holder and the tool part when the device rises and falls).

As already mentioned, the ventilation gap can preferably be kept constant during the rest phase. Optionally, cooling air can be blown to the front of the bristle carrier via the ventilation gap. This allows the rest period to be shortened in time.

Another special feature of the invention is that after a feed movement of the tool part and bristle carrier relative to each other, which is completed when reaching a closed position of the device, the pressure force over a predetermined holding time in the closed position is exerted on the bristle carrier. Despite the effort to keep the cycle times as low as possible this peculiarity of the invention so not driven to the device and immediately reopened, 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. With increasing deformation of the bristle carrier thus the compressive force will decrease.

The hold time should be at least 1 second, preferably at least 1.5 seconds.

The maximum hold times have been found to be optimal for 3 seconds, in particular for a maximum of 2.5 seconds. More is not required.

The bristle carrier can be heated during the holding time, in particular during the entire holding time, but optionally also already during the Züstellbewegung on the front. If it is already heated during the feed movement, cycle time can be saved. In fact, even during the feed movement, there is already a heating of the front side, for example due to radiation. Then, as soon as the front contacts the heated tool part, during the subsequent closing of the device, the front side and the bristle carrier are heated and brought to temperature.

The contact time of pressure on the bristle carrier is determined by the sum of the holding time plus the time period during the feed movement, in which the front is first contacted by the tool part and at the same time the rear side of the holder and compressed until reaching the fully collapsed position. This exposure time should be at least 4 seconds, in particular at least 5 seconds. The maximum exposure time has been found to be 15 seconds, in particular a maximum of 10 seconds as the limit.

The holding time is preferably less than the above period when moving together, in which the bristle carrier is compressed. This collapse and compression takes place with very slow delivery speed of the holder relative to the tool part. In particular, this period is at least 3, in particular at least 4 seconds. Experiments have shown that the holding time is a maximum of 50%, in particular a maximum of 40% of the above period when moving together, during which the bristle carrier is compressed.

To reduce the cycle time, it may be useful to heat the front of the bristle carrier already by other means and not only by contact with the tool part. The bristle carrier can be preheated. For example, if the bristle carrier is already in the holder, it could be blown on its front side with hot air or briefly exposed to a heat source (e.g., radiant heat) that does not form the tool part. This can take place during the feed movement from tool part to holder or even before this feed movement. Thus, for example, during an adjustment movement of the holder / tool part or before the tool part is moved laterally to the holder, the bristle carrier could be heated. The subsequent heating time by contact with the tool part can be reduced.

Another special feature of the invention is that the free end of the at least one bristle in the device is supported frontally. This support is intended to fix the axial position of the bristle or bristles of one or more bristle tufts within the same bristle tufts or bristle tufts to each other. For example, in the case of a plurality of bristle tufts, the brush should have a sawtooth shape at the ends of the bristle tufts, as viewed from the side. Other options are that a bristle tuft is sawtooth, tapered or tapered. It would be expected that this support, which serves as a stop or means for shaping, should also act during the application of the compressive force to the bristle carrier, in order to allow no displacement of the bristle, bristles or bristle tufts during this time. However, it has been found that it is advantageous, the support at least during the application of the compressive force on the bristle carrier, preferably before the application of the compressive force or during the feed movement of the device after contacting the front and the back of the bristle carrier by tool or holder already to remove. That means, at least in the last phase during the application of the compressive force, optionally also during the entire time of applying the compressive force, the previously used support is removed. The minimum pressure which is introduced into the bristles by the support at least in the last phase or also the entire phase of the deformation process can lead to the deformation of the bristles or to the fact that the bristles are inclined or not aligned parallel to one another, not even inside a bristle tuft.

In this context, it may be useful that the cross section of the at least one bristle and the cross section of the associated receiving opening in the tool part are coordinated so that the at least one bristle / the at least one bristle tufts is clamped in the receiving opening and axially positionable by the clamping , Thus, when the bristles or bristles of a bristle tuft are axially aligned, they are clamped in the receiving opening and thus positioned axially. Of course, this clamping is only a minimal clamping, which allows shifting generally in the previous axial viewing process. By the weight of the bristle / bristle tufts or by the inertia during the movements of the device, however, there is no automatic, unwanted displacement of the bristle / bristle tufts in the receiving opening. Similar to the anchorless attachment used in practice, the at least one bristle or tuft may be given a thickened attachment end by thermally forming the bristle material by heating above the melt temperature. When using a tuft of bristles, the bristles of the bristle tufts are combined together by thermal forming. In this case, but not adjacent bristle tufts are united with each other, but each bristle tuft has a thickened attachment end, with the advance it is introduced into the anchoring opening.

The forming takes place outside an anchoring station in which at least steps c) to f) are carried out.

The material of the thickened attachment end is therefore preferably already solidified when the respective attachment end is inserted into the anchoring opening. By means of the invention not only bristle tufts can be secured in the anchoring opening by reshaping the edge of the opening, but also prefabricated so-called elastomeric cleaning elements (eg of thermoplastic materials) which are several times thicker than normal filaments of bristle tufts. These cleaning elements serve to improve the cleaning as well as, in the case of a toothbrush, the massage of the gums. Furthermore, these cleaning elements do not necessarily have a pin shape, but may have any cross-sections, in particular elongated, arcuate, cruciform or round (circular or oval) shapes and corresponding ring shapes with central openings.

The at least one anchoring opening can be filled with a singular, prefabricated bristle made of an elastomeric material, in particular a thermoplastic elastomer (TPE). This singular bristle is anchored in the anchoring opening by deforming the bristle carrier. Preferably, the singular, prefabricated bristle has a greatest wall thickness, measured in cross section, of greater than 0.6 mm, in particular greater than 0.9 mm. For example, in a rectangular cross-sectional shape, the largest wall thickness is measured in the longitudinal direction.

Optionally, the singular, prefabricated bristle has a thickened attachment end with which it is pushed into the anchoring opening and which is encompassed by the deformed edge of the anchoring opening of the bristle carrier. The thickened attachment end is created in the manufacture of the singular bristle and not by the indentation and elastic deformation of the bristle by reshaping the edge of the anchoring opening. Alternatively, however, it would be possible to work without a thickened attachment end, namely, if the bristle is thick enough and the edge is pressed into the elastic bristle, so that then the attachment end thickened by the displaced material.

The thickened attachment end, for example, has 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 of another, preferably harder material, such as polypropylene, as at least the outer surface of the singular, prefabricated bristle be outside the anchorage opening. Preferably, the attachment end is even harder than the entire remainder of the singular prefabricated bristle. Due to the harder attachment end of the bristle seat in the anchoring opening is better. Usually, a plurality of anchoring openings are provided in the bristle carrier, wherein at least one, preferably a plurality of anchoring openings are provided only with the / the singular, prefabricated bristles. On the other hand, at least one other, preferably the remaining anchoring openings are provided with prefabricated bristle tufts, so that the brush has a mixed form of conventional bristle tufts and thicker, elastomeric cleaning elements.

Seen in side view, the singular bristle protrudes with its free end, for example, at least as far as the free end of the bristle tuft, and is thus not shorter than the bristle tufts. It may be advantageous if the elastomeric cleaning elements, i. the singular bristles are even longer than bristle tufts and protrude beyond their ends. Of course, the elastomeric cleaning elements may also be shorter than the bristle tufts.

Another special feature of the invention is that the wall defining the anchoring opening in the bristle carrier is deformed after deformation only from the front side to above the thickened end. The attachment end may be, for example, a thickened end or the thickened attachment end of a bristle tufts, in which the bristles integrally merge into one another. It would be expected that the entire anchoring opening is as tight and gap-free as possible at the attachment end to allow any movement of the bristle or bristle tufts in any direction. However, the invention takes a different approach. The attachment end is not completely compressed, but has some free space within the anchoring opening. As a result, the position of the at least one bristle, but in particular of the bristles within a bristle tuft, can be set more precisely. For example, if the thickened end of a bristle tuft is completely compressed, the bristles try to spread apart and no longer have the parallel alignment. For example, the deformation should take place only in the region of the edge of the anchoring opening, ie in the region of that wall section which lies in the region of the mouth of the anchoring opening.

With reference to the finished brush, the wall of the anchoring opening does not clamp the attachment end of the bristle or the at least one entire bristle tufts over a depth of at least 1 mm, in particular at least 0.8 mm, and / or does not deform the attachment end either. This area, in which no clamping and / or no deformation of the attachment end, begins with the bottom of the anchoring opening and extends further over the at least 0.8 mm toward the front of the bristle carrier.

There may even be an air gap between the wall and the at least one bristle / bristle tuft, in particular in the region of the bottom or adjacent to the bottom of the anchoring opening. As previously mentioned, the at least one bristle or the at least one entire bristle tuft may have a thickened attachment end. The edge of the anchoring opening is deformed, ie the area of the wall that lies in the area of the mouth to the front. In this area, the edge is narrowed so that the anchoring opening expands in the direction of the ground and the thickened attachment end is pulled behind in the extension direction by the deformed edge, so that extraction of the bristle / bristle tuft is prevented by the stop acting as an edge.

The constricted "neck" of the anchoring opening near the mouth formed by the deformation, ie the deformed edge of the anchoring opening that engages behind the thickened attachment end, can, for example, have an axial extension (axial in the context of the invention always in the direction from the front to the back or from of the back side to the front side) of 0.5-1.3 mm, in particular 0.6-0.9 mm, which is an extremely small height The brushes produced by the invention, in particular toothbrushes, can have a very small amount due to the invention Thickness in the area of the bristle carrier Thickness of over 4 mm, the invention allows a thickness of less than 4 mm, with better holding forces for the bristles or bristle tufts than in the prior art. Furthermore, it is possible due to the invention, bristle tufts, even larger bristle tufts, to position very close to the edge of the front, which was previously not possible.

Bristle tufts can also be narrowed in cross section by deforming the edge of the anchoring opening. That is, a bristle tuft is fixed in the anchoring opening, and the edge of the anchoring opening is deformed so that the edge compacts the bristle tufts in an area where the bristles are juxtaposed. The region in which the bristles lie next to one another preferably directly adjoins the attachment end, which is formed by the fused bristles. The bristle tufts thus receives a smaller cross-section after the deformation and narrowing of the anchoring opening than it had before after the insertion of the bristle tufts into the anchoring opening.

It is preferably provided that the bristle tufts are compressed by at least 3%, in particular at least 5%. This compaction is determined by the difference in cross-section, more specifically the difference in cross-sectional area, of the receiving opening in the tool part to the cross-section of the deformed anchoring opening in the region of the edge, i. the mouth of the anchoring opening to the front, defined.

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

Preferably, prior to its deformation, the anchoring opening only has an oversize side of less than 0.2 mm in relation to the largest cross-section of the attachment end of the tuft / bristle in order to allow insertion of the attachment end into the anchoring opening without effort. After deformation, a positive connection results through the narrowed edge of the anchoring opening, in which the edge can only be narrower by 0, 1-0.3 mm in cross section than the largest cross section of the attachment end. This minimum projection is sufficient to realize excellent pull-out values. The invention also makes it possible to process bristle carriers with elastomers already sprayed on the back. The elastomer is thus already sprayed onto the back of the bristle carrier when the bristle / bristle tufts is inserted into the front anchoring opening. The holder, in which the bristle carrier is received when applying the pressure force, has a recess. This recess is designed so that it receives the bristle carrier back together with elastomer. The recess may in particular be designed to be complementary to the shape of the bristle carrier provided with the encapsulation. Since the elastomer toothbrushes is usually designed as a tongue cleaner with protruding nubs, the holder has correspondingly complementary recesses for these nubs.

Preferably, however, the depth of the recess is designed so that its volume for receiving the elastomer is smaller than the uncompressed volume of the elastomer. Thus, the volume in the receptacle is adjusted to the actual volume of the compressed elastomer upon application of the compressive force to deform the edge of the anchoring opening. Since the elastomer is softer than the bristle carrier, it must be prevented that the pressure force is too low due to the intermediate elastomer.

The opposing force applied during deformation of the holder can be completely introduced via the elastomer in the front part of the bristle carrier. It does not necessarily take place directly contacting the back of the bristle carrier without the interposition of elastomer with the holder to initiate opposing forces in the bristle carrier.

The aforementioned various options of the method according to the invention can have the following optimized steps:

The tool part is heated so that the bristle carrier opposite end face of the tool part is brought to a temperature which is 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 and / or 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. According to a further aspect, the method according to the invention for producing a brush, which has a bristle carrier with at least one anchoring opening and at least one bristle inserted into the anchoring opening and anchored therein in an anchorless manner, wherein the bristle carrier and the at least one bristle are formed from a thermoplastic material may be the same or different, 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. The thermoplastic material in all embodiments is preferably made 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) existing group. Both homopolymers and copolymers with said thermoplastics can be used.

According to the invention, the bristle carrier and the at least one bristle inserted into the tool part should not melt when the tool part contacts the bristle carrier. The predetermined temperature is for this purpose preferably at most 85 %% of the melting temperature of the thermoplastic material. Thus, damage to the bristles and / or the bristle carrier can be reliably prevented.

Preferably, the predetermined temperature is in a range between 30 ° C and 150 ° C, more preferably between 60 ° C and 140 ° C, in particular between 90 and 130 ° C or 100 and 1 15 ° C. The predetermined temperature is more preferably above the glass transition temperature of the thermoplastic. This provides adequate deformability of the thermoplastic material.

The inventive method differs fundamentally from the prior art, because on the one hand, it provides exclusively a anchorless attachment of the bristle, the tufts of bristles or bristle tufts. The anchoring opening itself is prefabricated, that is, holes are not pressed into the bristle carrier here with heated punches, but rather the receiving openings already result during the injection molding of the bristle carrier. Furthermore, the receiving opening is not heated on the inside first and thus softens the inside edge of the opening, so that the bristle or bristle tufts is pressed into the soft wall of the receiving opening. Rather, the bristle or the bristle tufts is preferably first inserted into the receiving opening, and only then the bristle carrier is heated on its front side opposite the tool part, but without melting. It is carried out below the melting temperature of the bristle material and / or the bristle carrier material, wherein the heating by the tool part in which the bristle or bristle tufts sat, takes place and not by its own pure heating tool, which then has to be moved away again when the bristle or the bristle tufts is supplied. Such heating up by the tool part itself, in which the bristle or bristle tufts sit, is therefore neither envisaged in the prior art nor suggested by him, because the bristle tufts in the prior art should penetrate into the soft, heated wall of the bristle carrier and therefore a had to have high intrinsic stability in order to forward the pressing force exerted on the bristle tufts. Only by the pressing force exerted on the bristle tufts on the reverse side and by the inherent stiffness of the cold bristle tuft was it possible to press the anchoring end into the softened wall of the bristle carrier. In addition, the heating takes place by contacting the bristle carrier by the heating tool part itself and not, as in the prior art mainly usual, by contactless heating. Thus, the energy transitions are on the one hand faster attainable and on the other hand, the device with fewer parts executable. The heating of the bristle carrier during the entire forming process is carried out to a temperature below the melting temperature, preferably to a temperature which is well below the melting temperature, for example, at least 15% below the respective melting temperature calculated in ° C and preferably at most 15% above the glass transition temperature, calculated in ° K and in a bristle carrier material with a glass transition temperature greater than or equal to 300 ° K. In the case of a bristle material having a glass transition temperature of less than 300 ° K, the temperature to which the bristle carrier is heated during the entire forming process is at most 50% above the glass transition temperature in ° K calculated. Preferably, the bristle carrier is heated to a temperature above the glass transition temperature.

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

The glass transition temperature can be determined, for example, by dynamic mechanical thermal analysis (DMTA). The melting point of semicrystalline thermoplastics is considered to be the upper end of the melting range. A determination of the melting temperature can be carried out, for example, by differential scanning calorimetry (DSC). For amorphous thermoplastics, the transition to the flow or processing range is considered to be the melting temperature.

In order for the clocking in the manufacture of bristle carriers to be relatively short, an embodiment of the invention provides that the tool part, before contacting the bristle carrier, is heated up. Of course, this has the disadvantage that the bristle or bristle tuft itself is already heated with what was not desired in the prior art, because the bristle tufts should indeed 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. The invention provides inter alia in one embodiment of the invention, that the melting temperature of the plastic of the bristle carrier is below the melting temperature of the bristle or bristles. However, there are also brushes in which the bristle carrier material is equal to the bristle material, for example polypropylene and PA.

As already explained, the bristle carrier should be heated only after the introduction of the at least one bristle through the tool part, preferably exclusively by contacting. Of course, if a bristle carrier comes close to a hot or hot tool part, a minimal increase in temperature will occur, but this increase in temperature is absolutely negligible and occurs only on the immediate surface.

However, should the feed movement take a very long time, it is alternatively conceivable for the tool part to bring the bristle carrier in the area of the contact surface with the tool during the feed movement of the tool part to the temperature below the melting temperature of the bristle carrier material and, preferably, greater than or equal to the glass transition temperature the material of the bristle carrier is. Alternatively or additionally, the bristle carrier can be brought to the aforementioned temperature even when the bristle carrier is contacted by the tool part. The heating of the bristle carrier to the predetermined and aforementioned temperature or temperature ranges should according to one embodiment of the invention 0.25 to 0.5 mm below the tool part facing surface of the bristle carrier (front) reach until the deformation process is completed. Since the tool part presses against the bristle carrier over a longer period of time and heats it, the heat energy also migrates deeper into the interior of the bristle carrier. As a result, when the bristle carrier is first contacted by the tool part, it does not already have to be heated to depth, it is sufficient to achieve this heating during the feed movement and the contact time (contact time). The tool part can in a first phase of the feed movement relative to

Borstenträger bristle the bristle carrier at least in the region surrounding the anchoring opening edge, but preferably in the entire contact area, to a temperature 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 having a glass transition temperature greater than or equal to 300 ° K. This applies in particular to bristle carrier materials such as polypropylene variants with a glass transition temperature 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 the case in particular 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 the at least one bristle.

In particular, the bristle carrier material may be heated to a temperature which is within a range between the glass transition temperature and below about 85% of the melting temperature of the thermoplastic in ° C. Depending on the thermoplastic material used, this temperature is preferably in a range of between 30 ° C and 2 0 ° C, more preferably between 60 and 140 ° C, preferably between 90 and 130 ° C or 100 and 1 15 ° C. As has been found in experiments, the bristle or bristle tufts 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 region 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 having a glass transition temperature greater than or equal to 300 ° K (this applies in particular bristle carrier materials such as polypropylene variants with a glass transition temperature 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, ie in particular P polypropylene variants with such low glass transition temperatures. The edge the anchoring opening is at least the outer edge at the front of the bristle carrier.

Another variant of the invention provides that the at least one bristle or bristle tufts is first pushed into the receiving opening before the edge of the anchoring opening is heated to a temperature which is at least 30 ° C above the ambient temperature, in particular before the edge of the anchoring opening is heated in the interior of the anchoring opening over the ambient temperature by the tool part. This means that the edge inside the opening is not appreciably heated in the latter variant, in contrast to the prior art, where heated pins should penetrate into the opening to the inside edge of the opening, that is, the wall defining the opening, to the hole bottom to warm up.

The deformation should be such that the edge of the bristle carrier presses at the transition to the front or end side of the bristle carrier on the entire circumference against the outer bristles of the attached bristle tufts, so that a compression of the bristle tufts takes place. Of course, the nature or extent of compaction depends on the cross section of the bristle tuft. In the case of toothbrushes, the cross-section of the anchoring opening is reduced, for example, by a maximum of 0.3 mm, preferably by a maximum of 0.15 mm. Preferably, the lack of heating of the opening wall also relates to the other embodiments. This means that optionally only in the region of the front side, ie at the transition of the front side to the anchoring opening, the edge is brought to the predetermined limit temperatures or temperatures, in the opening itself, however, the ambient temperature is substantially maintained as long as the tool part does not contact the bristle carrier ,

A preferred embodiment of the invention provides that the tool part is also heated in the entire contact region, in which the tool part contacts the bristle carrier, and not only in the punctiform region or linear region around the edge of the anchoring opening. This has the advantage that the tool part has the entire contact area and thus the entire adjoining material area of the tool part available to this material area by the high applied pressure to move and reshape. Moreover, it is advantageous if the tool part even contacts the entire end of the bristle carrier facing the tool part, that is to say its front side, but at least contacts and pressurizes at least 70% of the area of the front side. In the prior art, a kind of collar was created by projecting beads on the bristle carrier produced, which represented the only heated and formed material. The present invention, however, sets this clearly off by just the portions of the bristle carrier are heated and formed with, which lie away from the front edge of the anchoring openings. The back side of the bristle carrier should not be heated by the tool part during anchoring so that in fact only the front side facing the tool part is heated and reshaped, whereas the back side forms a plate-like, stable structure which could be called the base of the bristle carrier , Consequently, this part of the bristle carrier is not reshaped or changed in shape during the pressurization.

The tool part can, at least during the entire time in which it exerts pressure on the bristle carrier, also heat the bristle carrier on the front side. Thus, the invention is not a short-term pre-heating of the bristle carrier and a subsequent rapid movement of the bristle tufts in the heated material portions of the bristle carrier, as is the case in the prior art with the previously heated bristle carriers into which bristle tufts are then pushed ,

The plastics used in the present invention are, for example, copolyesters, especially Eastar ™ BR003 (having a melting temperature range of 230 to 280 ° C), polypropylenes, in particular a homopolymer such as PPH5042 having a melting temperature of 165 ° C, polycarbonate, polyamide, polyvinyl acetate or polyethylene. If these materials have a glass transition temperature above the ambient temperature, here 300 ° K, energy should be introduced into the bristle carrier via the tool part. This is also advantageous for materials whose glass transition temperature is below ambient temperature. However, it is according to a variant of the invention in such materials of the bristle carrier also possible to get along without heating the bristle carrier by the tool part. Then, at the ambient temperature, the deformation is achieved exclusively via the pressure of the tool part on the bristle carrier.

Advantageously, bristle carrier materials are heated to the following temperatures in the process according to the invention and by the device according to the invention which is explained below:

The invention provides in particular for PET, a heating of the front side of the bristle carrier in a range of 75-95 ° C, in particular 80-90 ° C and PP of 115 to 125 ° C, in particular 1 10-120 ° C before.

In particular, PP is used with a melt flow index (MFI) of 6-35, preferably 10-15. The inventive method provides in the preferred embodiment, not only a bristle, which is used in total in a receiving opening, but a plurality of anchoring openings and a plurality of receiving openings in the bristle carrier or in the tool part. The receiving openings are aligned in each case to the associated anchoring openings. In the receiving openings bristle tufts are used, which are then inserted into the anchoring openings, preferably inserted simultaneously. The tool part simultaneously heats up 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 at the same time, thereby anchoring the bristle tufts at the same time.

Preferably, the contact area between the tool part and bristle carrier on the tool part is flat, as is the front side of the bristle carrier, which faces the tool part. However, there are also bristle carriers that have a convex or concave curved front. The tool part has a complementary end face.

The feed movement of the tool part relative to the bristle carrier can be performed pressure and time-controlled and / or pressure and path controlled. Alternatively, the device is simply driven to block by, for example, an electric motor is provided (for example via a spindle drive), the current consumption or power consumption of the electric motor is detected and is assumed from reaching a predetermined limit that the device is in the closed position in which preferably the holder and the tool part touch each other. From then on, the so-called hold time could run.

The term "movement or advancing movement of the tool part relative to the bristle carrier" means that one of the two parts or both parts are moved relative to one another A further variant of the invention provides for the tool part to be moved away from the

Time of contacting the bristle carrier exerts a preferably constant compressive force over a predetermined time on the bristle carrier. This optional method is particularly easy to implement, because it is simply applied a compressive force and exercised for a while on the bristle carrier, so to speak as a contact time, then to remove the tool part and bristle carrier again from each other. Further method steps are not required here, as in the other variants of the invention, to anchor the bristle or the bristle tufts in the bristle carrier.

The feed movement and / or the applied pressure from the tool part relative to or on the bristle carrier can extend from the contact of the bristle carrier through the tool part to reach the maximum feed path non-linear over time. As a result, for example, a longer or shorter initial exposure time of the temperature can be realized, and then another pressure is then applied to further and permanently deform the bristle carrier material.

In contrast to the aforementioned prior art, the attachment end of the at least one bristle or bristle tufts, when inserted into the associated anchoring opening (s), may be smaller than the cross-section of the anchoring opening, of course prior to its deformation and prior to heating of the bristle carrier , be. This means that the bristle tufts are not pressed into the lateral wall of the anchoring opening, as has been proposed in the prior art. The attachment end is also not pressed into the bottom of the anchoring opening, because this is not or not sufficiently heated to be soft. Furthermore, no axial force is exerted on the bristles, which goes beyond the necessary force for pushing out the bristles from the receiving opening.

Important for the present method and a great difference from the prior art is the relatively long exposure time of the tool part on the bristle carrier, while the pressure is exerted on the bristle carrier and this 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 be consistent and / or permanent heating of the bristle carrier occur. The anchoring opening may be a blind hole, in particular with a maximum depth of 4 mm, more particularly a maximum of 2.7 mm.

Due to the fact that the bristle carrier is deformed in the area of the front side, the thickness of the bristle carrier is reduced by the method according to the invention. The anchoring opening is reshaped and narrowed only to a depth of at most 85%, in particular a maximum of 70%, preferably even only a maximum of 60% of its total depth, that is, it is not narrowed in the region of the bottom of the blind hole.

A significant further difference from the prior art also exists in the applied pressure, which is considerably higher than in the previously proposed method. The tool part brings namely a pressure of at least 200 bar, in particular at least 400 bar on the bristle carrier.

The invention also makes it possible to produce brushes with bristle tufts which run obliquely to the front. This is surprising because the oblique orientation of the bristle tufts the mouth edge of the anchoring opening sections so to speak below the inclined tufts and thus is harder to reach for the tool for forming and on the other hand, the forming of the material in this area actually erecting the obliquely Tufts should lead. However, as has been found in experiments, this is not the case. By means of the method and device according to the invention, bristle tufts can thus also be installed obliquely in the bristle carrier.

As a tool part in particular a magazine is used, which is equipped with the at least one bristle or at least one bristle tufts. If several bristles or more bristle tufts to be attached to the bristle carrier, then all bristles or tufts are housed in the same magazine and are inserted after loading simultaneously.

The or the attachment ends of the bristles or bristle tufts protrude after loading with its attachment end of the magazine and are heated at this attachment end, without having to leave the magazine. The thickening is then formed at the free end protruding from the magazine attachment end. The magazine is not just a stamping tool, but Also, a transport tool, which is moved laterally to the bristle carrier coming from an assembly station and then pressed against the bristle carrier.

The thickening, i. the thickened attachment end may subsequently, i. be actively cooled immediately before it is produced, before it is inserted into the anchoring opening in the bristle carrier. This can increase the cycle time. In addition, it is avoided that the thickening is then deformed during application of the compressive force so that the bristles are no longer optimally aligned with each other. The active cooling does not mean, for example, that the thickened attachment end in the device is cooled by the ambient temperature prevailing there. Rather, a device for cooling is provided, for example, an active air flow, which is generated by a fan. This air flow can either transport ambient air, for example from farther away from the heated parts, or also transport cooled air coming from an air conditioning system. Another possibility is to provide a cold chamber through which the attachment end is transported with the bristle or through.

As already mentioned, the tool part has, for example, a planar end facing the bristle carrier (at least in the area of contact with the bristle carrier) and / or a geometry which can not protrude into the anchoring opening, ie without pin-like projections or the like, as in the prior art Technique was proposed.

As has been found, the position of the so-called parting plane between the holder and the tool part, in which both abut against each other, relative to the bristle carrier is important. So it is advantageous if the cavity formed for receiving the bristle carrier is formed not only in the holder, but also partially in the tool part. Based on the thickness of the bristle carrier, however, the vast majority of the cavity is formed by a recess 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 of the bristle carrier, ie outside the rounded transition. Thus, this rounded transition never with any heel or burr created by the bristle carrier's extruded material.

By applying pressure and heat or only by pressure, the total thickness of the bristle carrier is permanently reduced, that is, not only partially, but in total. The bristle carrier opposite end face of the tool part is brought in particular to a temperature which is a maximum of 140 ° C, in particular a maximum of 130 ° C. For example, polypropylene, PET, ABS or SAN is used here as material for the bristle carrier.

When using PET as a bristle carrier material, it has been found that the front side of the bristle carrier during forming to 75-95 ° C, especially 80-90 ° C, and when using PP (for example, with a melt flow index (MFI)) from 6-35, preferably 10-15, to 105-125 ° C, especially 110-120X should be brought.

At the bristle carrier, as already briefly mentioned, at least one frontally projecting, elastic cleaning element made of an elastomer, in particular TPE, injection-molded and attached to the bristle carrier, before or after attachment of the at least one bristle, wherein the cleaning element at the edge of the bristle carrier and / or inwardly of the edge between bristles or bristle tufts is arranged. Consequently, mixed forms of cleaning elements in the same brush are conceivable. Injected cleaning elements, tufts of bristles, which are attached to the bristle carrier by reshaping the edge of the anchoring opening, as well as singular bristles in the form of elastomeric, prefabricated cleaning elements, which are also secured by forming the edge of the anchoring opening on the bristle carrier, can be attached to the bristle carrier in any combination , Further, the brush body may be formed as a multi-component injection molded part

The bristles may also be pre-sharpened, that is to say chemically or mechanically sharpened bristles or pre-rounded. In the same bristle carrier a plurality of bristle tufts can be anchored, wherein at least one bristle tufts of bristles of a different material with a different melting temperature than the bristles at least one other bristle tufts exists. The bristle tufts, which consist of different bristle materials, are heated to different degrees in order to fuse the bristles of a tuft together in each case 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 and / or different, to different temperatures, depending on the bristle material heated heaters matched to the associated bristle material are used.

For example, the bristle books are pressed out of the magazine at different distances. Those tufts of lighter melting material remain e.g. closer to the magazine than the others, so that the tufts of bristles, which have moved further out, come closer to the heating device than the others and are therefore more heated. Alternatively, the bristle tufts can also be processed one after the other by successively pushing the bristle tufts having different bristle materials out of the magazine with their attachment end, in order then to get closer to the heating device. Either the heater is then heated to two suitable, different temperatures, or different hot heaters are used for their respective associated bristle tufts.

For a nylon brush and PBT bristles, e.g. First, the bristles of nylon heated and then the PBT. The aforementioned advantageous variants can also be combined with each other expressly.

The invention furthermore relates to a device for producing a brush having at least one bristle or at least one bristle tuft, which has a bristle carrier with at least one anchoring opening for the at least one bristle or at least one bristle tuft, for carrying out the method according to one of the preceding claims in that the device has several stations, including a spray station for producing the bristle carrier and a later Anchoring station for attaching the at least one bristle in the bristle carrier, wherein in the injection station a Spritzgußformhälftenteil is present with at least one protruding into a Spritzkavität pin which forms a portion of the Spritzgussformhälftenteüs and generates the formed as a blind hole anchoring opening, wherein the pin from a bottom surface of the Injection mold half parts and wherein at the transition of the bottom surface to the pin a chamfer for forming the complementary chamfer on bristle carrier in the transitional edge is formed, and that the device has a tool part with at least one receiving opening for the at least one bristle or at least one bristle tufts, wherein the Receiving opening opens on the bristle carrier facing the front side of the tool part, and wherein the tool part has at least a portion of the front side heating heating, which is formed and so ge It is regulated that the front side is heated to a maximum temperature of 140 ° C, in particular a maximum of 130X.

The term "injection mold half" is understood in the following to be an integral part which completely forms the inside of the cavity in the injection mold half, or a part or an assembly of several parts of a multi-part injection mold half understood, in which several parts together the inside of the cavity in the In the latter case, in particular the bottom portion of the cavity in the half of the injection mold is a separate part displaceably inserted into an opening of a second part which in turn defines the edge of the cavity Rather, the individual stations can, of course, also be spatially separated from one another at different locations e beveled at the transition edge, which then provides the benefits of compressing the bristle carrier and anchoring the bristle tufts.

The tool part exerts a pressure of at least 200 bar, in particular at least 400 bar on the bristle carrier. In order to produce the aforesaid advantageous dimensions of the chamfer at the transition edge, the complementary chamfer on the injection mold half at the transition between the pin and the bottom surface has an axial length of at least 0.1 mm to a maximum of 0.5 mm, in particular a maximum of 0.35 mm , and a radial width of at least 0.1 mm to a maximum of 0.35 mm.

Finally, the invention also relates to an injection mold half part, which is used in the aforementioned spray station. The injection mold half has at least one pin projecting into a syringe cavity forming a portion of the mold half and forming the anchoring opening formed as a blind hole, the pin projecting from a bottom surface of the mold half and having a taper to form the complementary taper at the bottom surface to pin junction is formed on the bristle carrier in the region of the transition edge. The bevel on the injection mold half has at the transition between the pin and the bottom surface an axial length of at least 0, 1 mm maximum 0.5 mm, in particular at most 0.35 mm, and a radial width of at least 0, 1 mm to a maximum of 0.35 mm.

The half-mold part may have an insert made as a separate component, which projects into a hole of the remaining half-mold part and projects with a free end opposite to the front side and thus forms the pin. This can greatly simplify the production of the injection mold half as a whole, because recesses do not have to be milled or eroded out of the bottom surface. Rather, holes are to be made, in which then an insert is inserted, which has the pin.

The insert itself can also be designed to have a socket which sits in the hole and the free end which forms the pin has a reduced width with respect to the socket. In this case, the bevel is completely formed on the insert, because the base forms the transition between the pin and the rest of the bottom surface. The pedestal may also define part of the floor surface itself.

In particular, polypropylene, PET, ABS or SAN is used here as material for the bristle carrier. In the device according to the invention, a tool part, which acts as a temporary support for the bristle or the bristle tufts or used as a press die and at the same time as a means of transport. A heater on the front side of the tool part is designed and is controlled by a controller that the front side is heated to a temperature of 140 ° C maximum, in particular at most 130 ° C when it is moved against the bristle carrier. A device that can theoretically drive higher temperatures, but whose control or regulation limits the temperature accordingly predetermined, of course, also falls under the device defined by definition. As explained above in connection with the method, the feed movement of the tool part can be realized relative to a holder of the bristle carrier by movement of the holder and / or the tool part, wherein the feed movement pressure and time-controlled and / or pressure and path controlled or only time-controlled or can only be driven away. 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.

The heatability of the tool part should be performed in the entire contact area with the bristle carrier or even in the entire region of the end face of the tool part, which is opposite to the holder and thus the bristle carrier used in the holder.

As further explained already in connection with the method according to the invention, the tool part is for example a magazine which is equipped in a loading station of the device with the at least one bristle or the at least one bristle tufts. The at least one bristle or the at least one bristle tufts (under "at least one bristle" generally fall, for the entire present description and the claims also one or more bristle tufts) protrude from the magazine after being loaded with its attachment end. which is located after the placement station, the or the attachment ends is heated, which in each case forms a thickening.When using one or more bristle tufts, the bristles of the corresponding Bristle tufts united by thermal forming together. It forms in particular a kind of mushroom, dome or spherical thickening.

In general, in the device according to the invention, either the magazine can be moved and the stations can be stationary, or the magazine remains stationary and stuffing tools or heating devices or holders are moved to the magazine. These tools or stances may be arranged, for example, on a rotating carousel, which successively leaves magazines which are stationed. The device according to the invention has a controller which controls the feed movement of the tool part relative to the bristle carrier and the heating process of the tool part in such a way that the tool part is heated before it makes contact with the bristle carrier. This means that before the feed movement of the tool part in the direction of the holder, the tool part is already warm. At this stage, but not necessarily, the maximum operating temperature may be present. The bristle carrier is heated only after the introduction of the at least one bristle through the tool part, which is realized by the projection of the thickened end relative to the magazine and the distance of the end face of the magazine to the corresponding contact surface on the bristle carrier.

The device according to the invention is in particular designed so that the tool part is permanently heated to the desired temperature, which is necessary for heating the front side of the bristle carrier for the deformation process. This means that the tool part is also already warm and at this desired temperature when the at least one bristle or bristle tufts are introduced into the receiving opening or receiving openings. If, during the melting of the bristle ends, the tool part also receives the at least one bristle tufts, care must be taken that the temperature of the tool part and / or the residence time of the at least one bristle / bristle tuft in the receiving opening are not sufficient a deformation of the bristle or bristles of a bristle tufts leads.

The controller can heat the tool part to such a temperature and control the delivery of the tool part to the bristle carrier so that the tool part the bristle carrier in the region of the contact surface with the Tool part brings during the feed movement of the tool part to the bristle carrier and / or upon contacting the bristle carrier to a temperature which is below the melting temperature of the material of the bristle carrier and, preferably, greater than the glass transition temperature of the material of the bristle carrier, in particular wherein the controller is configured programmed in that, in the case of a bristle carrier material with a glass transition temperature of greater than or equal to 300 ° K, the temperature of the tool part is set at 15% above the glass transition temperature in ° K and at a bristle carrier material with a glass transition temperature of less than 300 ° K at most 50% above the glass transition temperature in ° K adjusts.

Of course, in the method according to the invention or the device according to the invention brush body or bristle carrier can be supplied, which are produced in the standard single or multi-component injection molding process. Thus, handles, or more generally, brush bodies or bristle carriers can be used, which are used in toothbrushes that are traditionally stuffed with the (metal) anchor technique. Usually, however, these handles / brush body / bristle carrier have deeper anchoring openings than is necessary in the inventive method. In the case of anchor technology, multi-component handles or brush bodies or bristle carriers have already been used for years, where elastomeric structures are injection-molded in the head region of the brush body between the anchoring openings and / or the edge of the brush head. Also on the back of the brush head z. B. elastomeric tongue cleaner and sprayed be. All these possibilities also apply to the method and the device according to the invention.

In anchor technique, these elastomeric structures are placed on the front or back before the bristles occur. Only exceptionally, the attachment of the elastomeric structure after the bristle occurs, which is not common. Most often, in a multi-component injection molding tool, these elastomeric structures are sprayed onto a stiffer support structure. Such multi-component tools for toothbrush bodies are very common. The handles, brush body / bristle carriers, which are supplied in the method according to the invention and / or the device according to the invention can be easily sprayed with all brush body injection molding techniques and tools known today. The anchoring openings are pre-molded by means of molding pins, which may have round or any cross-sectional shape and which protrude into the injection cavity. These pins can then be pulled out of the cavities after sufficient cooling and / or curing of the injected plastic, z. B. by means of slides before a complete demolding of the injection molded part takes place. The so-called mold pins can be mounted parallel and / or angled to each other, so as to produce parallel and / or angled anchoring openings in the injection molded part. In the method according to the invention and the device according to the invention, pens can typically dip somewhat less deeply into the injection cavities when spraying such parts than when spraying brush bodies or bristle carriers which are to be filled with the anchoring technique. As a result, the anchoring openings in the spray lengths are somewhat less deep. Since these openings are less deep, the total head thickness of the brush, which are produced by the method and apparatus according to the invention, run significantly lower than brush heads, which are stuffed with the anchor technique. This results in the production of toothbrushes a clinical advantage.

The method and apparatus according to the invention have particular advantages when using clear, i. transparent materials for the bristle carrier or the brush body. Such materials are usually PET, copolyester, SAN, ABS, etc. These materials may also have pre-injection molded anchoring openings, as with bristle carriers / brush bodies / handles made of polypropylene, and / or be provided with elastomers (eg TPE, TPU) in a multi-component process. After the bristle carrier / brush body / handles are then injected in a multi-component process, they can be further processed as described above and then described with reference to the device, as the invention provides.

In the process of making the brush temporally and / or spatially in front of the station with the holder and acting, for example, as a ram Tool part can be provided a spray station for producing the tufts carrier, wherein in the injection station a Spritzgußformhälftenteil with at least one protruding into a Spritzkavität pin which is immovably attached to the Spritzgussformhälftenteil or part, possibly one-piece part thereof, is present. Thus, the currently used in injection mold halves active slide partially or even completely redundant. Each pin produces namely an anchoring opening formed as a blind hole. Gate valves are not only expensive to manufacture, but also expensive in terms of maintenance and repair. Because the bristle or bristle tufts are not fixed with an anchor in the bristle carrier in the apparatus according to the invention, which requires a minimum depth for the anchoring opening, anchoring openings with a shallower depth are completely sufficient for fixing the bristle or bristle tufts. It should be emphasized that, of course, the spray station does not necessarily have to be placed spatially next to the station with the holder. Rather, the spray station may be located locally in another manufacturing facility or in a remote manufacturing location, eg, in another city, such that the bristle carriers may be prepared, for example, and then transported to another facility or manufacturing facility to provide the bristle tufts to become. The injection mold half part can be formed in the embodiment by a first part and / or an insert received in the first part. The insert has the pins that protrude from the insert on the front. The insert is slidable relative to the first part, in a corresponding opening in the first part which is closed by the insert. The device according to the invention 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 easily adjustable again.

There may be provided a plurality of electric motors for applying the pressure force. Furthermore, an electric motor can also apply pressure to a plurality of bristle carriers at the same time by delimiting a plurality of cavities between a tool part and a holder. To the discharge rate of To increase device, in particular a plurality of electric motors are provided, each of which act on a plurality of bristle carrier with pressure.

Furthermore, the use of turntables or the like makes sense to increase the discharge rate. Depending on, for example, in which stations a longer cycle time is required, several units may be provided.

The apparatus of the invention should have a controller programmed to permanently heat the tool part to the desired temperature during application of the pressure to the bristle carrier. There are thus no desired temperature fluctuations in operation, so there is no heating time for the tool part, which would adversely affect the clock rate.

Incidentally, it is expressly pointed out that the advantages and features mentioned above in connection with the method according to the invention are also applicable to the devices according to the invention, individually or in combination, according to the method according to the invention.

It should also be emphasized that the method according to the invention and the device according to the invention can be used with any brushes, not only with toothbrushes. For example, methods and apparatus for household brushes, scrubbers, household brooms or brooms of any kind, dishwashing brushes, toilet brushes, hairbrushes, vacuum cleaner brushes, handwashing brushes and brushes of any kind, for example, for painting, painting or nail polish brush, facial brushes (as well as toothbrushes manual or electric brushes ) deploy. Consequently, the details and variants described in the following drawings can also be used for all these brushes.

Further features and advantages of the invention will become apparent from the following description and from the following drawings, to which reference is made. In the drawings show:

- Figure 1a to 1g different sequential steps of the method according to the invention in a perspective plan view and perspective bottom view, which also shows the device according to the invention,

FIG. 2 shows an enlarged view of the perspective bottom view of the anchoring station in FIG. 1e,

3 is a cross-sectional view through the anchoring station shown in FIGS. 1e and 1f, prior to the magazine and bristle carrier being moved toward one another;

FIG. 4 shows a corresponding view of the station according to FIG. 3 upon first contacting of the magazine and the bristle carrier;

FIG. 5 shows a corresponding view of the anchoring station according to FIG. 3 after the end of the feed movement and after the end of the contact time, immediately before moving apart and opening the station;

FIG. 6 shows a sectional view through an alternative placement station, FIG. 7 shows a sectional view through the anchoring station according to FIG. 3, in which obliquely directed bristle tufts are processed,

8 shows a sectional view through a first embodiment of an injection mold and an injection mold half part according to the invention for injection molding a bristle carrier, which is used in the method according to the invention and in the device according to the invention; FIG. 8a is an enlarged detail view of the area designated X in FIG. 8 according to a first variant;

FIG. 8b shows an enlarged detail view of the region designated X in FIG. 8 according to a second variant,

FIG. 9 is a front view of a bristle carrier produced in the present invention;

FIG. 10 shows another injection mold and another injection mold half part according to the invention for injection molding a bristle carrier used in the method according to the invention and in the device according to the invention,

FIG. 11 is a sectional view through a bristle carrier during insertion of bristle tufts and / or individual elastomeric bristles;

- ^'Figure 12 variants used in the invention singular, pre-made bristles, FIG. 13 variants of the method according to the invention and the device according to the invention,

FIG. 14 shows a perspective view of a bristle carrier produced in an injection mold half part according to the invention for carrying out the method according to the invention,

FIG. 15 shows an enlarged sectional view through the bristle carrier according to FIG. 14,

FIG. 16 shows an enlarged sectional view through the bristle carrier according to FIG. 14 after the insertion and before the deformation of the bristle tufts, the magazine not being shown for the sake of simplicity,

Figure 17 is a greatly enlarged detail sectional view through a bristle tufts and the surrounding bristle carrier after deformation, wherein in the left and in the true half of the drawing differently shaped bristle carrier are shown as variants, and

- Figure 18 is an enlarged perspective top view of a bristle carrier produced in a Spritzgußformhälftenteil invention according to another variant.

FIG. 1 shows a device for producing brushes, for example toothbrushes. Such a toothbrush is known to have a brush head with bristles tufts protruding from the front, a neck and a handle. These three sections can merge into one another in one piece, they form the so-called brush body. The brush head can be either directly padded, or it can be made in two parts, with a plate-like bristle carrier, which already has prefabricated blind hole-like anchoring openings after injection molding, said plate-like bristle carrier is then brought together with the rest of the head, either by welding, gluing or by overmolding. An alternative to this is that the brush head is made in one piece so that it forms the bristle carrier itself. Such an embodiment is shown in Figure 1, the brush head simultaneously forms the bristle carrier 10. In this illustration, the bristle carrier 10 at the same time the brush body, because it includes style, neck and head of the brush. The bristle carrier 10 is a prefabricated, injection molded part. Figure 2 shows that the bristle carrier 10 on its underside numerous prefabricated, the Injection molding produced openings 12 has, are inserted into the bristle tufts and anchored therein. However, the following description is identical to plate-like bristle carrier 10 transferable and readable.

The apparatus shown in Figure 1 comprises a plurality of stations, namely a loading station 14 shown in Figures 1a and 1b, a melting station 16 shown in Figure 1c and an anchoring station 18 for the bristle tufts shown in Figures 1e and Fig. 1f is shown.

All stations are run by a magazine 20, also called tool part, which transports bristle tufts through the individual stations.

Although a magazine 20 is shown in Figure 1 with later shown in more detail receiving openings for a brush, the magazines 20 are in practice preferably so large that a plurality of adjacent groups of receiving openings for a plurality of brushes in the magazine 20 are formed. There may also be multiple rows of groups of multi-brush receiving openings.

The magazine 20 is, for example, a plate-shaped part with a constant thickness, which has a top, according to Figure 1, flat end face 22. Alternatively, the magazine, which is substantially plate-shaped, on its flat face 22 has a recess 200 with a bottom 202, which may also be flat, as shown in Figure 14, to a portion of a cavity for receiving the bristle carrier 10 form.

Since the magazine passes through several stations and is subsequently used for the production of further brushes, a magazine circulating mode is present in the device, whereby numerous identically designed magazines 20 are successively clocked by the individual stations. The magazine 20 is thus a transport means for bristle tufts 24 through the device. Alternatively, the magazine may be stationary and the individual stations are clocked around the magazine, for example on a carousel. At the same time several stationary magazines can be processed, more precisely the bristle tufts arranged in the magazines. The magazine 20 has numerous receiving openings 26 which have a hole pattern which corresponds to the hole pattern of the bristle carrier 10.

Each bristle tufts 24 consists of several bristles which are separated from a bristle supply and, as shown in FIG. 1a, are inserted into the magazine 20, for example via pins, as will be explained later. The individual bristle tufts 24 can be transported by means of pipes with compressed air or vacuum.

The bristles are made of a thermoplastic material, in particular PA, PBT, polyester, copolyester or polypropylene, but they may also consist of elastomers. Furthermore, it is also possible to use coextruded bristles, for example with a core of PA with elastomer coating. As will be explained later with reference to FIGS. 11 and 12, it is not absolutely necessary that exclusively bristle tufts 24 be inserted and embedded in the anchoring opening, but only a singular, prefabricated bristle in the form of an elastomeric cleaning element, for example its anchoring opening according to the above-mentioned and subsequently described method used and fixed. Such cleaning elements are sprayed or foamed separately and are softer than the bristle carrier 10. The bristle tufts 24 have opposite ends and protrude with their rear ends 28, called mounting ends, something out of the magazine 20, so they are slightly opposite the front page 22. This is shown in FIG. 1 b.

The magazine 20, which is completely equipped with the bristle tufts 24, is transported laterally into the melting station 16, as shown in Figure 1 c. In this station, a heater 30 is provided, which may be, for example, a plate heater or a hot air heater. The back 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 attachment end. The bristles of a bristle tufts 24 are thus integrally connected to each other. The thickening 32 of a bristle tuft 24 does not pass into adjacent thickenings of the adjacent bristle tufts 24, but remain spherical. or lenticular thickenings. Also preferably no stamp is pressed against the thickening or the still liquid material of the molten bristle ends.

In the same bristle carrier 10 a plurality of bristle tufts 24 can be anchored, wherein at least one bristle tufts 24 made of bristles of a different material with a different melting temperature than the bristles of at least one other bristle tufts 24. The bristle tufts 24, which consist of different bristle materials, are heated to different degrees in order to fuse the bristles of a tuft together in each case to form a thickened attachment end. This can be implemented in various ways: The distance between the end of the bristle tufts 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 and / or different depending on the bristle material heaters 30, heated to different temperatures, tuned to the associated bristle material are used.

For example, depending on the bristle material, the bristle tufts are pushed out of the magazine 20 at different distances. Those bristle tufts 24 of lighter melting material remain e.g. closer to the magazine 20 than the others, so that the more advanced bristle tufts 24 get closer to the heater 30 than the others and are therefore more heated.

Alternatively, the bristle tufts 24 can also be processed one after the other by the bristle tufts 24 having different bristle materials being successively pushed out of the magazine with their attachment end, in order then to come closer to the heating device 30. Either the heater 30 is then heated to two suitable, different temperatures, or different hot heaters 30 are used for their respective associated bristle tufts.

The pushing out of individual or groups of bristle tufts takes place, for example, with a divided base plate 44 (see FIG. 5) whose parts can be moved independently of one another in the longitudinal direction of the bristle. Even in the melting station 16 or on the way to the subsequent anchoring station 18 or in the anchoring station 18, optionally, the thickenings 32 can be actively cooled. This takes place, for example, by means of a cold air stream 214 brought in via a fan (see FIG. 1d) or by the station 1d being designed as a cold chamber, through which the magazine 20 is passed with thickenings 32 which are still soft at the rear. By cooling the thickenings 32, the cycle time can be increased.

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 arrested in the anchoring openings 12 of the bristle carrier 10 exclusively in a permanent manner.

The anchoring station 18 comprises at least one holder 34 (preferably a plurality of holders 34) which has on its front side 22 opposite end face 36 (see FIG. 2) a recess 38 (with several bristle carriers 10 to be accommodated a plurality of recesses) which are complementary to the corresponding shape of the bristle carrier 10 is formed so that it rests flat with its back on the holder 34 (see also Figure 14).

The holder 34 itself has a flat end face 36 opposite which, however, the bristle carrier 10 protrudes somewhat, as shown in FIG. 2, in order to project into the recess 200 complementary to the area of the front side of the bristle carrier 10 in the magazine 20, as shown for example in FIG ,

The magazine 20 is heated, for example, either by an externally supplied plate heating, which is moved laterally in the anchoring station 18 to the magazine 20 and this, since the magazine 20 is made of metal, can heat up quickly.

Alternatively, in the magazine 20, a heater, in particular an electrical resistance heater 39 is formed, which is shown in Figure 2 and in Figure 14. The Heizwindungen are symbolically indicated, they are close to the end face 22 and at a recess 200 near the bottom 202 of the recess 200, which is part of the end face 22. 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 driven into the anchoring station 18 in order to activate the heater 39. Of course, it is also conceivable that the end face 22 including the bottom 202 of the recess 200 itself represents an electrical resistance heating, so that here directly the front side is heated.

If the magazine 20 is fixed, the electrical connection for the heater is very easy to implement, it can be permanently formed.

The heater 39 ensures that preferably the entire end face 22, which comes into contact with the bristle carrier 10, is heated, that is to say also the sections between the thickenings 32.

The temperature at which the end face 22 (in the region of the contact with the bristle carrier 10) is brought thereby, is below the melting temperature of the bristle and / or the bristle carrier material, preferably both materials. In particular, it is at most 85% calculated in ° C of the respective melting temperature of these materials. If, for example, both materials have a melting temperature of 100 ° C., then the temperature of the finally heated magazine 20 at the end face 22 is at most 85 ° C.

FIG. 3 shows a sectional view through the anchoring station 18 in FIG. 1 e, before the magazine 20 and the bristle carrier 10 are moved toward one another.

The thickening 32 has such a dimension, seen in the longitudinal direction A (also called axial direction or feed direction) that it is smaller than the corresponding cross-section of the anchoring opening 12, so that they, without the inside edge of the anchoring opening 12, also inside 40 of the anchoring opening called bounding wall, abut or contact the inside 40, can be inserted into the anchoring opening 12.

In particular, the cylindrical anchoring opening 12 at this time has only an excess of a maximum of 0.2 mm, in particular a maximum of 0.15 mm with respect to the largest cross section of the thickening 32 (attachment end). In other words, the lateral dimensions of the thickened attachment end are smaller than the lateral dimensions of the Anchoring opening 12 even in the region of the bottom 208 of the anchoring opening.

The underside of the thickened attachment end 32, with which the bristle tufts 24 is guided into the anchoring opening 11, is rounded or bevelled.

As explained later, the at least one anchoring opening is injected. It has an inner side 40 with a draft angle, that is, the inner side is still running toward the bottom 208 slightly toward the inside.

The permanent, i. During the entire operation to the desired temperature heated magazine 20 and / or the holder 34 are moved towards each other relative to each other, in the present case, only the holder 34 is moved with the bristle carrier 10, so first the thickening 32 passes into the anchoring opening 12 before the end face 22 contacts the facing flat front and front side 42 of the bristle carrier 10. During the advancing movement of the bristle carrier 10 is virtually not heated at all, as long as the bristle carrier 10 is not contacted by the magazine 20, since the feed movement is very rapid and no residence time in the open position of the anchoring station 8 shown in Figure 3 is present.

A base plate 44 (see FIG. 3) on which all bristle tufts 24 rest with their front end free ends and which forms a support may serve to align the bristle tufts 24 at their front end with one another, if desired is to create between the thickening 32 and the end face 22. The base plate 44 serves as a support for the individual bristles and for the bristle tufts 24.

FIG. 4 shows that the end face 22 contacts the front side 42 of the bristle carrier 10 and thus heats the bristle carrier 10 over the entire contact area between the two parts.

The bristle carrier 10 is made of thermoplastic material, in particular of the plastics already mentioned above, such as polypropylene, ABS, PA, PBT, PET or PC. However, the movement of the holder 34 does not remain in the position of the first contact, which is shown in Figure 4, because on the holder 34 and the magazine 20, a very high pressure on the bristle carrier 10 is applied.

For example, a pressure of at least 200 bar, preferably at least 400 bar, is exerted on the bristle carrier 10 when driving on each other. This pressure is already applied from the first contact of bristle carrier 10 and magazine 20 and remains the same over the contact time (contact time).

This pressure is maintained with simultaneous heating of the bristle carrier 10 over a contact 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.

The exposure time is composed of a holding time and a period of time (called the compression time) during the feed movement, which begins when the front side 42 of the magazine 20 and at the same time the back 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 tool part for the holding time is kept constant. The hold time is the time in which the feed motion is completed, i. 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.

During the compression time, the distance of the holder to 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.

During the exposure time, the magazine 20 is preferably still heated, and under certain circumstances, the large mass of the magazine 20 would also allow it to stop the heating after the first heating to the operating temperature. Nevertheless, a heating of the bristle carrier 10 would continue to take place during the contact time. The device is driven in particular to block, ie, the holder 34 contacted outside the cavity formed by the recess 38 and the recess 200 with an end face 36 (see Figure 14) the portion of the end face 22 outside the recess 200. In this contact area is no Gap provided, could penetrate into the cavity of material, but the cavity is sealed by a circular peripheral contact area.

Incidentally, generally not limited to the embodiment shown, no heating in the contact area between the holder 34 and magazine 20 is present, so that the heater is present only in the region of contact between the front 42 and magazine 20 and acts.

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

It is advantageous if the support in the form of the base plate 44 is removed at least during the last phase of application of the compressive force, ie at the end of the contact time and no longer contacts the bristles. This improves the alignment accuracy of the bristles both relative to each other and relative to the bristle carrier 10. Preferably, however, the base plate 44 is already removed before the start of the holding time or even before the exposure time, as shown symbolically in the figures 3-5 with the arrow Y. For example, the base plate 44 is used only in the station c) and optionally d) according to FIG. However, in order to determine the axial position of the bristle tufts and the individual bristles during the entire contact time, the cross-section of the receiving opening 26 and the cross section of the bristle tufts 24 inserted therein are coordinated so that the bristle tufts 24 are clamped in the receiving opening 26 and thus axially is safely positioned. Due to its own weight or inertia during the movement within the stations and from station to station, the bristle tufts 24 are not displaced. In the example mentioned, the entire flat front side, at least where contact with the magazine 20 is present on the front side 42 of the bristle carrier 10, is heated. If the magazine 20 has a recess 200, it is sufficient and it is advantageous if only in the region of the bottom 202 of the recess 200, the heater is mounted. However, after the magazine 20 is usually made of steel, the entire magazine 20 is heated. The temperatures that are set, however, is to bring the front side 42 of the bristle carrier 10 to the desired temperature.

The temperature at which the bristle carrier is heated in the region 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 lower than 85% of the respective melting temperature, calculated at ⁰ C. This corresponds to this temperature Alternatively, at least the edge 50 of the anchoring opening 12 can be heated in the region of the front side 42, which forms the region of the wall of the anchoring opening 12, which adjoins the Mouth adjacent to the front 42.

The temperature to which the bristle carrier 10 is brought at least in the region of the edge 50, preferably in the entire contact area with the magazine should not only be below or significantly below the melting temperature of the materials, but in a range of 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 which is above a limit temperature, which 60% in ° C, especially 80% in ° C is the glass transition temperature of the bristle carrier material, if the bristle carrier material has a glass transition temperature greater than or equal to 300 ° K. However, this limit temperature is preferably at or minimally above the glass transition temperature. For a bristle carrier material with a glass transition temperature of less than 300 ° K, the heating temperature is not more than 50% above the glass transition temperature in ° K calculated.

Another variant provides that the heating of at least the edge 50 of the front side 42, in particular the entire contact surface of the bristle carrier 10 is heated in the region of the front side 42 to a temperature which is at least 30 ° C above the ambient temperature, in particular before the inside 40 is heated in the interior of the anchoring opening 12 through the ambient temperature by the magazine 20. As can be seen in the figures, the magazine 20 has no projections or the like, with which it would protrude into the anchoring opening 12, since it has a flat end face 22 and a flat bottom 202 in the region of the front 42.

Since the front 42 is flat and in the region of the mouth of the anchoring opening 12, that is in the region of the edge 50, no collar or the like is present, as was the case in the prior art, the application of pressure and temperature, the bristle carrier material in the area of the front 42 optionally even over the entire surface deformed. The material wants to dodge and thus migrates into the anchoring openings 12 in the region of the mouth and constricts them.

By applying heat and pressure, the entire thickness D and thus the maximum thickness of the bristle carrier 10 in the region of the mouth of the anchoring opening 12 to the front 42 is reduced permanently. The result is a kind of bead or constriction, which engages behind the thickened attachment end in the extension direction and thus secures the bristle tufts 24.

Adhesion between the thickened attachment end and the wall of the anchoring opening 12 does not occur.

The reshaping of the edge does not have to be extreme. It has been found that with toothbrushes, for example, it is sufficient to reduce the cross-section of the anchoring opening 12 with the original width or the original diameter D3 in the region of the edge 218 (see FIG. 5A) only to a width or an inner diameter D1 the difference between the width or the diameter D2 of the thickest point of the thickening 32 (relative to the respective cross-sectional plane) to the width or the diameter D1 in the region of the edge 218 is only about 0.1-0.5 mm. It is advantageous if the thickening 32 has an undersize with respect to the still undeformed anchoring opening 12 during insertion (ie D2 is smaller D3).

By virtue of this idea of inserting the thickening 32 into the anchoring opening 12 in the not yet completely solidified state, it is also possible to generally use a thickening 32 which is formed with an oversize relative to the cross-section of the anchoring opening 12, i. D2 the same size as D3.

In Fig. 5A, the space formed by the anchoring opening 12 and defined outwardly by the constricted edge 218 for accommodating the thickening 32 is exaggerated, just as the thickening 32 is exaggerated relative to the diameter D1.

The fact is, however, that not the entire wall forming the anchoring opening 12 rests on the thickening 32 or on the outer bristles emanating from the thickening 32. Rather, the wall is deformed only in the region of the edge 218 and in a directly adjacent thereto, widening outwardly toward the bottom 208 section 220 and is only in these areas of the bristles or the thickening 32 and exerts a pressure on them out.

However, the thickening should contact the ground 208 to precisely define the axial position of the bristle tufts.

In the remaining area, for example between bottom 208 and thickening 32 or in the region of the circumference of the wall adjacent to the floor 208, there are one or more air gaps 222 between the wall and the outside of the thickening 32, so that they are not compressed in this area, jammed and / or deformed.

In the region of the edge 218, the bristle tufts 24 are densified with respect to their condition in the magazine 20 by the narrowing and constriction of the edge 218 by at least 3%, in particular at least 5%. Here, the cross-sectional area of the receiving opening in the magazine is compared with the cross-sectional area of the edge 218 at its narrowest point. All anchoring openings 12 are simultaneously closed by the illustrated device and the corresponding method and thus anchored all bristle tufts 24 in the bristle carrier 10 at the same time.

As further seen in Figures 5 and 5A, 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 an axial extent of 0.5-1, 3 mm, in particular 0.6-1, 0 mm. The depth t is measured from the front 42. If the front side 42 is flat, the plane resting on the front side 42 is used as a reference surface. If the front side 42 is curved concavely or convexly, an envelope of the front side 42 is formed, from which the depth t is measured.

The thickening 32 itself is preferably clamped only in the axial direction over a maximum of 50% of its total axial length in the anchoring opening. The rest of the clamping takes place in the region of the bristles emanating from the thickening 32.

The wall of the anchoring opening 12 is not deformed over a depth Z (see Figure 5A) of at least 0.8 mm, starting from the bottom 208 and / or does not pinch the thickening 32 and the bristles in this area. The depth T of the anchoring opening after the production of the brush is a maximum of 4 mm, in particular a maximum of 2.7 mm.

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. The anchoring thus created is the only anchorage for the bristle carrier, no metal anchor or metal wire is necessary.

It should be emphasized in general that this does not only refer to the illustrated embodiments, that the bristle carrier 10 should not be brought close to its melting temperature, but from this clearly removed close to the glass transition temperature. In particular, the heating temperature and thus also the temperature at the magazine 20 should be in the region of the front side 22 and the bristle carrier 10 frontally not higher than 15% above the glass transition temperature of the bristle carrier material and / or the bristle material.

When PET is used, 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., with PP to a temperature of 105-125 ° C., in particular 1 × 10. 120 ° C. In particular, the PP is selected to have a melt flow index (MFI) of 6-35, preferably 10-15 in the initial state. An embodiment of the invention provides that the end face 22 and thus the bristle carrier 10 are heated to a temperature of at most 140 ° C, in particular at most 130 ° C, preferably in the range of 100 to 115 ° C are heated. As materials in particular polypropylene, PET, ABS, copolyester and SAN are used for the bristle carrier here. 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 towards the front side 42) should not be deformed. In order to shift the temperature limit from which a deformation would take place due to the applied pressure as close as possible to the front side 42 of the bristle carrier 10, the holder 34 may be provided with an active cooling.

In Figure 3, this cooling is symbolized by cooling channels 210, flows through the cooling liquid. The cooling channels 210 are connected to a cooling water circuit which pumps cold water, preferably of less than 20 °, in particular even less than 10 ° C., through the holder 34. The rear side 206 thus becomes a maximum of 25 ° C during the application of the compressive force. The side surface of the bristle carrier 10 connecting the front side 42 and the back side 206 can also 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.

After the predetermined contact time bracket 34 and magazine 20 are moved apart again, so that the bristle tufts 24 from their Receiving openings 26 are pulled out. A post-processing in the form of a different shape for the bristle carrier 10 is not required.

The moving apart is preferably not in one piece, but it is built a rest phase in the process of moving apart. For this purpose, tool part, ie magazine 20, and holder 34 are minimally removed from each other, so that between the front 42 and the top of the tool part, ie the magazine 20, a small ventilation gap 228 (see Figure 5A) of greater than or equal to 0.5 mm results. When this predetermined ventilation gap 228 is reached in its height, the distance for the resting phase, which is at least 1 second, in particular at least 1.5 seconds, preferably remains constant.

Optionally, in this quiescent phase cooling air can also be blown in to the front side of the bristle carrier 10 via the ventilation gap 228 in order to cool the front side. During this resting phase, however, the bristles remain in the receiving opening 26, as shown in FIG. 5A. In the resting phase, the deformed area of the anchoring opening stabilizes, so that the bristles of a tuft parallel to each other and evenly directed.

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

In order to precisely control the corresponding movements and temperatures, the device has a controller 51, by means of which not only the heating temperature but also the pressure applied and the movements are controlled. The heater 30 can be controlled via the same controller 51. If the bristle carrier material is a material such as certain types of polypropylene in which the glass transition temperature is not above the ambient temperature, heating of the bristle carrier may be dispensed with, but this need not necessarily be the case. Here, too, a minimum heating may be advantageous just above the glass transition temperature, but again well below the melting temperature. If it is not necessary to heat up such bristle carrier materials, then the anchoring openings 12 are produced exclusively by applying the aforementioned Closed pressure over the aforementioned exposure time. It is possible to use magazines 20 without heating or the same magazines with heating, the heater is simply not activated.

Regardless of the bristle carrier material 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 one or both of these parts can be moved towards the other part) can a pressure and time-controlled feed movement and / / or a pressure and path controlled feed movement be advantageous. In particular, it is advantageous if in a first phase of

Advance movement of the edge 50 or the entire front side 42 is heated to a temperature which is above a threshold temperature. This limit temperature is 60%, in particular 80% below the glass transition temperature of the bristle carrier material, determined in ° C when the bristle carrier material has a glass transition temperature of about 300 ° K. However, the limit temperature is preferably 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 the edge 50 is pressed against the bristles. Alternatively, the feed movement takes place at a constant, low speed, when the bristle carrier front and back contacted and thus axially compressed, and the magazine 20 and the holder 34 are driven on each block.

Even in the embodiment illustrated in FIG. 5, in the closed state, the material presses against the bristles in the region of the edge 50, so that there is no gap between bristles and edge 50.

The loading of the magazine 20 can either be carried out directly via a bristle separator, as in FIG. 1 a, or via another variant, which is shown in FIG. Here, first a cassette 60 is filled with numerous receiving openings with bristle tufts. About this cassette, the scattered bristle tufts can then be stored until they finally be pressed directly into the magazine 20 via movable pins 62, for example.

Alternatively, between the cassette 60 and the magazine 20 also a baffle plate 64 may be present, the oblique transport openings 66 has for moving through them bristle tufts 24. It is also possible, via converging transport openings 66, as shown in Figure 6 on the left, to unite several bristle tufts 24 to form a larger bristle tufts, for example, if the brush is to contain bristle tufts of different thickness. Furthermore, of course, the magazine may have inclined receiving openings 26, because there are brushes in which the bristle tufts are not perpendicular to the front 42 and thus cylindrical, but are arranged obliquely to her. Again, however, the anchorage is as shown in the figures. Alternatively, of course, the anchoring openings 12 for such obliquely directed bristle tufts 24 may be made slightly oblique or conical or conical only in the region of the inclined on them side of the tufts 24, as shown in Figure 7. This means that the receiving opening 26 may have differently inclined edge portions.

In the embodiment according to FIG. 7, an edge portion 80 of the anchoring opening 12 running obliquely, in particular parallel to the oblique receiving openings 26, and an edge portion 81 lying opposite thereto are provided. In the illustrated embodiment, the edge portion 81 is perpendicular to the front side of the bristle carrier 10. Alternatively, however the edge portion 81 also also obliquely, possibly in a different slope than the edge portion 80, as shown in broken lines. The bristle carrier 10 is produced in an injection molding apparatus belonging to the device according to the invention in an injection mold, as shown in two variants in FIGS. 8 and 10, with injection mold halves 100 and 102. This spraying station is connected upstream of the previously described station for stuffing the bristle carrier 10 in time and / or space, as already described above. The spray station forms a bristle carrier spray device. The injection mold halves 100 and 102 form therebetween a cavity 104 into which liquid plastic is injected to produce the bristle carrier 10. While in previously used spray stations the injection mold half 100 with was provided pin-shaped, active sliders that protrude through the injection mold half 100 into the cavity 104 and pulled out before opening the injection mold, this variant provides a much simpler solution. Namely, one or more integrally molded pins 106 of arbitrary cross-section are immovably attached to the injection mold half 100 and project freely into the cavity 104. These pins 106 then create the anchoring apertures 12. The depth of the anchoring apertures 12 is significantly less than previously manufactured bristle carriers stuffed with anchor technology. In FIG. 10, it can be seen on the right-hand pin 106 that it can be used to produce obliquely extending openings 12, such as those shown in FIGS. 7 and 8

In the case of a one-piece injection mold half (see Figure 10) in which a part defines the entire inside of the cavity, the injection mold half is referred to as a mold half mold part.

8) on which the extensions pins 106 sit, on which they are for example mounted in one piece. The insert 107 preferably has all the pins 106 which are necessary for the production of anchoring openings 12. After injection, the insert 107 is pulled down into a recess in the injection mold half for ease of removal, so that the pins 106 are pulled out of the sprayed anchoring holes 12, whereby the subsequent ejection or removal of the bristle carrier 10 is simplified.

In this case, the injection mold half 100 comprises a first injection mold half part 101, which defines the entire lower mold half 100 except for the region of the insert. Furthermore, the injection mold half 100 comprises the insert 107 which is received in the first part 101 in an opening 107 complementary to the insert 107 and forms a second injection mold half part. The insert 107 is movably supported in the direction of the tuft carrier and away from the tuft carrier relative to the first part 101 of the injection mold half 100. Between the first part 101 and the insert 107 preferably no gap is provided into which the liquid plastic can penetrate. In FIG. 10, it can be seen on the right-hand extension 106 that it can be used to produce obliquely extending openings 12, such as that shown in FIG. The pin 106 may have at least one edge portion extending obliquely to the adjustment direction of the insert 107 (see double arrow in FIG. 10). The insert 107 preferably defines the entire area of the front of the brush head. Through the insert 107 can be produced without great effort brushes, which have the same bristle carrier 10, but have a different hole pattern and a different pattern of bristle tufts.

In the variant according to FIG. 8a, all the pins 106 are integrally formed on the insert 107, which defines a half-mold half-mold. In the variant according to FIG. 8b, the half-mold part is made in several parts, as it comprises a base part 300 with a plurality of holes 302 and inserts 304 inserted in the holes 302. These inserts 304 have a base 306 with which they close the respective hole in the base part 300. From the base 306 of the respective pin 106 protrudes. This variant is easier to manufacture.

It is important in the production of the bristle carrier 10 that, where necessary, the so-called transition edges 320 (see FIG. 14) are chamfered between the front side 42 and the inside 40 of the anchoring opening 12. In Figure 14 it can be seen that not all transition edges 320 are such

Bevel 322 must have.

In the sectional view in Figure 15, the chamfers 322 are shown partially enlarged. In the enlarged views, the hatched areas K symbolically represent the material which no longer has the transition edge 320 due to the chamfer 322. As comparison lines, the continuation of the front side 42, also called envelope 323, and a line 324 are provided, which represents the linear continuation of the inner side 40 up to the envelope.

The chamfers 322 may have another cross-section from anchoring openings 12 to anchoring opening 12, which are shown for example in the enlarged view in FIG. Alternatively, as shown in Figure 18, the chamfer 322 along the circumference of Transition edge 320 have different cross-sections. Here, for example, in FIG. 18, a section 330 is bevelled more steeply than a section 332 of the same bevel 322.

The chamfers 322 may extend along the entire circumference of the transition edge or only over a portion. For example, it can be seen from the anchoring opening 12 'in FIG. 15 that the left side of the transition edge 320 has a chamfer 322 whereas the right side does not have a chamfer so that in this area the inside 40 runs at right angles to the front side 42 and onto it meets to form a sharp transitional edge.

If there are different cross-sections in a chamfer 322 along the circumference of the transition edge 320, they may begin at the same axial depth of the anchoring aperture 2 as measured from the front 42 adjacent the chamfer 322 or the portion of the front 42 adjacent thereto.

The chamfers 322 may be formed by a rounding, in particular a radius or a chamfer, as shown in the two middle magnifications in Figure 15,

The chamfer 322 is only at the mouth of the anchoring opening 12, i. exists in the region of the transition edge 320 and hardly extends into the anchoring opening 12. The chamfer 322 extends, measured from the front side 42 adjacent to the chamfer 322, a maximum of 0.5 mm, in particular at most 0.35 mm and at least 0.1 mm in the anchoring opening 12. The radial width of the chamfer 322 is in particular at least 0.1 mm and a maximum of 0.5 mm, in particular a maximum of 0.35 mm.

As can be seen with reference to FIG. 15, but also with reference to FIG. 14, even with a very thin web 340 between adjacent anchoring openings, this web 340 projects up to the front side 42 of the bristle carrier 10 and forms a section thereof. That is, the ridge protrudes up to the envelope of the front face 42 (if convex or concave) or if so Front 42 is flat, to the level of the front 42, without standing over it.

Since the anchoring apertures 12 and the front face 42 as well as the chamfers 322 are all injection molded, the associated half mold part has a chamfer 342 complementary to the associated chamfer 322 at the transition between pin 106 and bottom face (face side) of the half mold part. The above preferred dimensions for the chamfer 322 also correspond to the corresponding dimensions for the chamfer 342. In the embodiment of Figure 8b, the bottom (front) is also formed in sections by the insert, more precisely in the base 306. Thus, the chamfer 342 is completely formed in the insert 304.

When inserting the bristle tufts 24,24 'in the associated anchoring openings, the thickened attachment end do not contact the chamfers 322, because this the receiving openings in the magazine 20 are aligned too well on the anchoring openings 12.

When deformed form the chamfers 322 additional buffer spaces or receiving spaces for material, which is depressed and narrows the anchoring opening 12 at its mouth. In FIG. 16 it can be seen that bristle tufts 24 are inserted at right angles or, like the bristle tufts 24 ', at an angle to the front side 42. In the oblique bristle tufts 24 ', the chamfer 322 is formed larger at the bristle tufts 24' near side of the transition edge than at the remaining circumference of the transition edge. In the present case, there is no bevel even on the (right) side remote from the bristle tufts 24, and a chamfer 322 is present on the transition edge 320 in the remaining part of the circumference.

In Figure 17, an already anchored bristle tufts 24 can be seen in detail.

The corresponding magazine 20 has already deformed the material of the bristle carrier 10 in the region of the front side 42 in FIG. 17, so that the total thickness of the bristle carrier 10 is reduced. The material partially closes the anchoring opening 12, such as a bottleneck, and may press against the outer bristle tufts 24 (see the left half of FIG. 17) or may be slightly removed therefrom (see the right half of FIG. 17). However, the material that migrates inward does not enter the gap 350 between the receiving opening in the magazine 20 and the outside of the bristle tufts 24. Thus, no material migrates out of the anchoring opening 12 to protrude beyond the front 42.

Preferably, as seen in Figure 14, none of the anchoring apertures 12 has a projection projecting from the front side prior to forming. That is, the entire material with which the anchoring openings 12 are closed must be provided by reducing the thickness between the back 206 and the front 42 of the bristle carrier 10. FIG. 9 shows various variants of how the bristle carrier 10 can be designed. Not only can circular or oval anchoring openings 12 be provided, but any shapes can be designed. For example, elongate openings can be realized, X-shaped, C-shaped or any other designed anchoring openings. These large anchoring openings are equipped with bristle tufts, which are composed of several, isolated bristle tufts, which are connected by melting their ends to form a large bristle tufts. Such large bristle tufts provide a corresponding wall-shaped bristle structure.

It should be emphasized that the device according to the invention and the method according to the invention can be used not only with a plurality of bristle tufts but also only with a bristle tuft, for example for producing a brush, and for fastening only one or only individual bristles in a bristle carrier.

The anchoring openings 12 must therefore generally not necessarily serve only for receiving and fixing bristle tufts, but can be prefabricated, made of any elastomeric plastics, singular bristles of any shape exactly as previously described in connection with bristle tufts record and fix. These bristles can be a plate-shaped Have shape and can be, for example, in the elongated anchoring openings 12 and embed it by forming the edge of the anchoring openings 12. In the C-shaped anchoring opening 12, for example, a cross-sectionally C-shaped, pre-sprayed cleaning element is used as a singular bristle. In addition, of course, bristle tufts 24 consisting of numerous bristles 24 'in the bristle carrier 10 can be used. The singular bristles 24 'may, for example, also be positioned in the middle of a field of bristle tufts 24 or conversely surround one or more bristle tufts 24. It should be emphasized that the aforementioned features explained with reference to the bristle tufts can also be used for singular, large bristles. Just as an example, a plate-shaped bristle running obliquely to the bristle carrier 10 is used, which is inserted into the oblique anchoring opening 12 in FIG. 7 and anchored therein. However, the singular bristle may also have an anchoring end 32 from which the elongate remainder projects angled so that it can be inserted into a cylindrical anchoring opening 12 as shown in FIG. 4, but with the bristle outside the anchoring opening 12 sloping.

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

In addition or as an alternative to the above variants, elastomeric cleaning elements 108 may be injection-molded, for example, on the edge of the bristle carrier 10. These cleaning elements 108 are not prefabricated, but they are also front side opposite the bristle carrier 10 and are used for massage of the gums. The bristle carrier 10 may for this purpose, for example, at the edge holes or edge-side recesses possess, in which the cleaning elements 108 are injected. Furthermore, as is increasingly common in brushing, the back side of the bristle carrier 10 can be overmoulded with a softer plastic. In the latter case, it is advisable that the cleaning elements 108 integrally merge into the back layer of softer plastic. As shown by the upper half in Figure 9, which shows a variant of the lower half, this back 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.

Another variant is that the bristle carrier 10, here the head of the toothbrush, is coupled via a hinge 110 made of softer plastic with the neck of the brush body.

In general, for all variants that the bristle carrier can be a small plate as a part of the subsequent brush body or the entire brush body. For example, the bristle carrier may also be a multi-component injection molded part, which then already forms the finished brush body when the bristles are finally embedded. Conversely, however, it is also possible to embed the bristles in a part of the brush body, which then forms the bristle carrier, and then subsequently to overmold this bristle carrier which has been bristled.

Consequently, the injection station can also be designed as a multi-component injection station, or several injection stations can be provided, between which then lies the station in which the bristles are anchored. The cleaning elements 108 and / or the singular, prefabricated and in their cross-sectional shape arbitrary bristles of elastomeric material preferably extend forward at least as far as the bristle tufts, but they may also be beyond this or be shorter than this.

In Figure 11 it is shown that not only, as previously explained, bristle tufts 24 are inserted with their thickening 32 at the attachment end in the anchoring opening 12 and anchored therein by forming the edge, but that singular, prefabricated bristles 24 '(arbitrary Form seen both in side view and in cross-section) can be anchored anchorless by the aforementioned method and the aforementioned device in the bristle carrier. The bristles 24 'are injection molded from an elastomeric material, in particular TPE. The bristles 24 'have in their protruding from the bristle carrier 10 section a maximum wall thickness d (measured in cross section), which is greater than 0.6 mm, in particular greater than 0.9 mm.

Further, the prefabricated bristles 24 'may or should have a thickened attachment end 32', the height of which is less than the depth of the associated anchoring apertures 12 such that the inwardly formed edge engages around the attachment ends 32 'to achieve positive retention. The attachment ends 32 'are, for example, flat cylinders whose shape is adapted to the shape of the anchoring opening 12. However, the outer dimensions of the respective attachment end 32 'are matched to the cross-section of the anchor opening 12 such that upon insertion there is a lateral gap between the attachment end 32' and the wall of the anchor opening 12 before the reshaping takes place.

The attachment end 32 'may be of a different material, particularly a harder material than the remainder of the bristle 24'. An example would be an attachment end 32 'made of polypropylene. Also, only one core of the bristle 24 'may be made of a harder material which is then overmolded with a softer material. Thus, a disc made of harder material would be conceivable, which forms the entire or a core of the attachment end 32 '.

Likewise, according to FIG. 12, on the left, the disk 1 12 forming the core could have an extension 1 14 formed integrally thereon, which projects into the part of the bristle 24 'which will lie outside the bristle carrier 10.

The variant of a bristle 24 'shown on the right in FIG. 12 is formed with a fastening end 32' made of a hard plastic and a section 118 molded onto it made of a softer plastic. The singular bristles 24 'shown in Figure 12 are tapered, which is not meant to be limiting. FIG. 13 shows a complete device with various stations. It should be emphasized that the device according to the invention does not have to have all the stations which are explained below.

In particular, all variants and details which have been explained with reference to the preceding figures, in particular with reference to FIG. 1, can also be implemented individually or in combination also in this embodiment, irrespective of whether this is e.g. cooling, ventilation, etc., as well as the aforementioned temperatures, temperature ranges or times, and the materials used. In station A, bristles or bristle tufts are separated and transported on. The left picture shows a so-called fiber box 120, from which finished bristles, which may be mechanically or chemically sharpened, are taken through a tuft singler 122 in tufts.

These bristle tufts 24 are transported via a transport device to a station B, in which the bristle tufts 24 are then possibly already transferred to the final tuft geometry and into the hole pattern of the later brush.

For example, the bristle tufts 24 are inserted into a first intermediate magazine 124, in particular in the form of a plate. About the intermediate magazine 124, the bristle tufts 24 by means of plunger 126 then possibly pushed into another plate 128, in which optionally forming or deflection openings 130 or openings 132 for merging a plurality of bristle tufts 24 to a common larger bristle tufts or obliquely aligning bristle tufts 24 available are. The bristle tufts 24 are then pushed further into the magazine 20. In the magazine 20, the hole geometry of the later brush is then preferably realized, but this need not necessarily be the case, as will be explained later.

If necessary, however, namely 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 one final tuft layer or tuft geometry and the hole pattern of the finished brush.

The transport of the bristle tufts 24 after separation can take place mechanically via slides or the tappets 126 shown in FIG. 2 into the first intermediate magazine 124 and / or the magazine 20 in station B. In station A, as a further alternative in the second image from the left, it is shown that the separated bristle tufts are conveyed into the intermediate magazine 124 or the magazine 20 via tubes or hoses 134, in which an overpressure or a negative pressure is applied. No matter which transport means is used for the bristle tufts, which can be fed one after the other, in groups one after the other or all at the same time and / or inserted into the magazine 20.

A third alternative in station A shows a wound string 136 of parallel filaments. The strand 136 is wound on a roll 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. After cutting off the ends of the strand, cut bristle tufts 24 are produced. For example, by a movable XY table, the coil or the end of the strand received in a movable guide is relative to the magazine 20 or intermediate magazine 124 or, on the other hand, the magazine 20 / intermediate magazine 124 to be relative shifted to the end of the strand, so that all openings in the magazine 20 or intermediate magazine 124 are filled in succession. Furthermore, several coils and strands can be moved relative to the magazine 20 / intermediate magazine 124. Subsequently, the completely filled magazine 20 or intermediate magazine 124 is moved out of this station and transported to the station B or directly in station C. In station B, the plungers 126 push the bristle tufts 24 into the magazine 20.

In order to save the XY table, strands can also be transported by several rollers 138 into the individual openings in the magazine 20 or the intermediate magazine 124 and then cut off. Station C is a so-called profiling station. Here, the bristle tufts 24 are axially displaced so that the later ends of the tufts with which they are brushed lie in one plane or, more generally, end in a predetermined, arbitrary surface. In the illustrated embodiment, a waveform is predetermined, so a stop plate 140 with a complementary waveform is spaced from the magazine 20. The bristle tufts 24 are then pressed down by a pressure plate 142, which preferably has a complementary shape to the surface of the stop plate 140, until all tufts abut the stop plate 140.

However, station C may also be dispensed with if the desired profile can already be reached in station B by suitable plungers 126 of different lengths or lengths. The two variants can also be mixed together by a so-called pre-profiling in station B by differently long plunger 126 and then a fine profiling in station C by the stop plate 140.

Station D is a cutting station where the trailing ends of the bristle tufts are cut off to achieve optimal melting of the tufts in the subsequent station. The bristle tufts 24, which protrude differently far from the magazine 20 at the rear, are cut off mechanically by means of a knife 144 or thermally with a hot wire 146 relatively close to the magazine 20. Optionally, when using a mechanical knife 144, the magazine 20 may also act as a counter knife. In this case, the bristle tufts 24 after cutting off a little pushed back from the magazine 20 so that they withstand something over them.

If necessary, station D can be dispensed with if the tufts already protrude evenly to the rear of the magazine 20 after station B or C. This is especially the case when the front tufts ends are to end in a plane.

The overhanging portion of bristle tufts 24 is then melted at station E so that all the filaments of a tuft are bonded together, and that over the then resulting mushroom-shaped, thickened tufts. The thickness of the tuft ends is controlled by the amount of filament material that projects rearward of the magazine 20. This also allows the geometry of the tuft end set. Melting may be accomplished by a heated plunger 148 that may touch or be spaced from the tufts so that radiant heat (particularly infrared light) causes the filaments to melt. Alternatively, a fusion can also be achieved with hot air. It is important that only a single, associated thickening is generated for the bristle tufts formed, because only those filaments are to be connected to each other by the fusion, which should also be fixed later in the same anchoring opening. Optionally, a cooling of the thickenings 32 take place here, as explained above.

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

Another alternative is that a baffle plate is provided with corresponding channels, in which the bristle tufts 24 are inserted with their thickened attachment ends ahead, to then be pushed further into the anchoring openings of the bristle carrier. This variant is useful if in the magazine not quite the later hole pattern of the brush or the alignment of the bristle tufts 24 is realized. The above-mentioned separately produced singular bristles 24 'can be supplied arbitrarily in each station, either the magazine 20 or only the bristle carrier 10.

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

The electric motor is in particular a servomotor. In general, a plurality of bristle carriers 10 can also be deformed simultaneously with one drive in order to hold the at least one bristle or the at least one bristle tuft 24 in the anchoring opening. To increase the output of finished brushes, in particular several drives are provided side by side in turn, which in turn drive a plurality of brackets 34, which in turn receive a plurality of bristle carrier 10.

The controller 51 is designed accordingly programmed, that the aforementioned method is performed in the device. With the device according to the invention and the method according to the invention, bristle tufts can be anchored in the bristle carrier, which are extremely long and thin. The invention provides bristle carrier with bristle tufts of a length over 8 mm and a width of less than 2 mm, in particular less than 1 mm. The corresponding edges of the anchoring openings need not necessarily be formed by the same distance inwards at these large edge lengths. It has been found that it is sufficient to provide some further inwardly in the direction of anchoring opening deformed, overhanging edge portions which alternate with less far inwardly deformed edge portions.

Claims

claims

1. A method for producing a brush having a bristle carrier made of thermoplastic material having a front and a back and at least one anchoring opening, in which at least one, a thickened attachment end having bristle made of thermoplastic material and anchored therein anchorless, so that they from the front side of the bristle carrier protrudes, wherein the at least one anchoring opening is defined by an inner side and on the front side has a front edge surrounding the anchoring opening, characterized by the following steps:

a) the bristle carrier is provided, which has a transition edge to the inside in the region of the front edge, which is chamfered at least in sections over the circumference of the transition edge, wherein the anchoring opening and the transition edge are produced during injection molding of the bristle carrier,

f) the tool part exerts a compressive force on the heated bristle carrier and deforms the bristle carrier at least in the region surrounding the anchoring opening frontal edge while reducing the cross section of the anchoring opening such that the at least one bristle is embedded and anchored in the anchoring opening, wherein material of the bristle carrier in the region of the edge and the inside is pressed laterally into the anchoring opening and into the region of the transitional edge and presses against the at least one bristle, and

2. The method according to claim 1, characterized in that the chamfer extends along the entire circumference of the transition edge.

3. The method according to claim 2, characterized in that the bevel along the entire circumference of the transition edge has the same cross-section.

4. The method according to claim 2, characterized in that the bevel along the circumference of the transition edge has different cross-sections.

5. The method according to claim 4, characterized in that the bevel along the circumference of the transition edge has different cross-sections, which starts at the same axial depth of the anchoring opening, measured from the bevel adjacent front of the bristle carrier.

6. The method according to any one of the preceding claims, characterized in that the chamfer in the anchoring opening at a depth of at least 0.1 mm and a maximum of 0.5 mm, in particular a maximum of 0.35 mm, away from the adjacent to the bevel front of Bristle carrier begins.

7. The method according to any one of the preceding claims, characterized in that the chamfer has a radial width of at least 0, 1 mm and a maximum of 0.5 mm, in particular a maximum of 0.35 mm.

8. The method according to any one of the preceding claims, characterized in that the chamfer in cross section at least in sections by a chamfer and / or a bow, in particular a radius is formed.

9. The method according to any one of the preceding claims, characterized in that adjacent anchoring openings are separated therebetween by a web which is provided at least to one of the anchoring openings with the chamfer, wherein the web protrudes to the front of the bristle carrier and forms a portion thereof ,

10. The method according to any one of the preceding claims, characterized in that the front side of the bristle carrier is a flat or a convex or concave curved surface.

11. The method according to any one of the preceding claims, characterized in that a plurality of anchoring openings are provided, wherein at least some anchoring openings each have a bevel and the bevels of anchoring openings are different.

12. The method according to any one of the preceding claims, characterized in that the at least one anchoring opening of the bristle carrier in the region surrounding the anchoring opening end edge is reduced only to a maximum of the beginning of the thickened attachment end, in particular to a depth of at most 1 mm, in cross section ,

13. The method according to any one of the preceding claims, characterized in that the bristle carrier is compressed so that material of

Bristle carrier is pressed in the region of the edge and the inside laterally in the anchoring opening and in the region of the transition edge, without protruding beyond the envelope formed by the front of the bristle carrier to the outside.

14. The method according to any one of the preceding claims, characterized in that the thickened attachment end has a rounded or beveled bottom, with the advance it is guided into the anchoring opening.

15. The method according to any one of the preceding claims, characterized in that the inserted at least one bristle tufts so with its thickened attachment end in the anchoring opening is that the thickened attachment end does not contact the chamfer of the anchoring opening.

16. The method according to any one of the preceding claims, characterized in that the lateral dimensions of the thickened attachment end are smaller than the lateral dimensions of the respective associated anchoring opening in the region of the bottom of the anchoring opening.

17. The method according to any one of the preceding claims, characterized in that the bristle body is sprayed together with the at least one anchoring opening and the at least one anchoring opening has an inner side with a Entformungsschräge for demolding after injection molding.

18. The method according to any one of the preceding claims, characterized in that the bristle or bristle tufts is inserted obliquely to the front in the anchoring opening and the bevel is formed on the bristle or bristle tufts near side of the transitional edge greater than the remaining circumference of the transition edge or that there is no chamfer at the side remote from the bristle or bristle tuft and at the transitional edge a chamfer in the remaining part of the circumference.

19. The method according to any one of the preceding claims, characterized in that the back of the bristle carrier, while the pressing force is exerted on the bristle carrier, is actively cooled.

20. The method according to any one of the preceding claims, characterized in that the bristle carrier has a plurality of anchoring openings and none of the edges of the anchoring openings is provided with a projection which projects from the front side of the bristle carrier.

21. A device for producing a brush having at least one bristle or at least one bristle tuft, which has a bristle carrier with at least one anchoring opening for the at least one bristle or the at least one bristle tufts, for carrying out the method according to one of the preceding claims, characterized in that the contraption a plurality of stations, including a spray station for producing the bristle carrier and a subsequent anchoring station for attaching the at least one bristle in the bristle carrier, wherein in the injection station a Spritzgußformhälftenteil with at least one protruding into a Spritzkavität pin is present, which forms a portion of the Spritzgußformhälftenteils and the formed as a blind hole anchoring opening, wherein the pin protrudes from a bottom surface of the Spritzgußformhälftenteils and wherein at the transition of the bottom surface to the pin a chamfer to form the complementary chamfer on the bristle carrier in the transitional edge is formed, and that the device is a tool part with at least one receiving opening for the at least one bristle or the at least one bristle tufts, wherein the receiving opening opens on the bristle carrier facing the end face of the tool part, and wherein the tool part has a heating at least portions of the front side heating, which is formed and regulated so that the end face is heated to a temperature of at most 140 ° C, in particular at most 130 ° C.

22. The apparatus according to claim 21, characterized in that the device is designed so that the tool part can apply a pressure of at least 200 bar, in particular at least 400 bar on the bristle carrier.

23. The apparatus of claim 21 or 22, characterized in that the bevel on the Spritzgussformhälftenteil at the transition between the pin and the bottom surface an axial length of at least 0.1 mm to a maximum of 0.5 mm, in particular 0.35 mm maximum, and has a radial width of at least 0, 1 mm to a maximum of 0.35 mm.

24. Spritzgußformhälftenteil for the device according to any one of claims 21-23 for producing a bristle carrier _t for carrying out the method according to one of claims 1 to 20, characterized in that the Spritzgussformhälftenteil has at least one protruding into a Spritzkavität pin, a portion of the Injection mold half forms and which forms the anchoring opening formed as a blind hole, wherein the pin protrudes from a bottom surface of the Spritzgußformhälftenteils and wherein at the transition of the bottom surface to the pin is formed a chamfer to form the complementary bevel on the bristle carrier in the transitional edge wherein the chamfer on the injection mold half at the transition between the pin and the bottom surface has an axial length of at least 0.1 mm to a maximum of 0.5 mm, in particular a maximum of 0.35 mm, and a radial width of at least 0.1 mm to a maximum of 0 , 35 mm.

25. Injection mold half part according to claim 24, characterized in that the injection mold half part has a manufactured as a separate component insert which projects into a hole of the remaining Spritzgußformhälftenteils and projects with a free end opposite the front, thus forming the pin.