CN110545694A

CN110545694A - Method and apparatus for manufacturing brushes and injection-molded half-mould

Info

Publication number: CN110545694A
Application number: CN201880021585.1A
Authority: CN
Inventors: 巴尔特·杰勒德·布舍里
Original assignee: Gb Bushery Co Ltd
Current assignee: Gb Bushery Co Ltd
Priority date: 2017-03-27
Filing date: 2018-03-27
Publication date: 2019-12-06
Anticipated expiration: 2038-03-27
Also published as: BE1024476B1; CN110545694B; WO2018177592A1; TW201838545A; EP3599933A1; TWI751315B; EP3599933B1

Abstract

In a method or device for the fastenerless fastening of bristles in a bristle carrier (10), it is provided that: after the bristles are inserted into the fixed openings (12) in the bristle carrier (10), these fixed openings are closed by applying pressure and heat. A chamfer (322) is arranged around the transition edge (320) of the fastening opening (12).

Description

Method and apparatus for manufacturing brushes and injection-molded half-mould

Technical Field

The invention relates to a method and a device for producing brushes having a bristle carrier made of thermoplastic plastic, which bristle carrier has at least one fastening opening, in which at least one bristle is inserted and fastened, and to an injection-molded half-module.

Background

brushes, in particular toothbrushes and household brushes, are made in practice using two methods, namely: the bristle tufts are held with or without a holding member (sheet metal or wire loop). Unlike the use of fasteners, the method without fasteners sets: rather than folding the bristle tuft and securing it to the bristle carrier at the fold of the bristle tuft, one end of the bristle tuft is adhesively or thermally locked to the bristle carrier. The methods used in practice are set here: the bristle carrier has an opening through which the bristle tufts are inserted. The bristle tufts then protrude with their back-side ends out of the openings and are heated on the back side of the bristle carrier. The thermoplastic material of the bristles is thereby melted, the bristles thereby merging materially into one another and forming a thickening by means of which the individual bristles cannot be pulled forward. A large number of bristle tufts are usually liquefied on the rear side by means of hot air or a hot punch (Stempel), so that the material of the individual bristle tufts fuses with one another and forms a layer of liquefied bristle ends on the rear side. The rear side is then covered, in particular sprayed.

The disadvantages of this solution are: since the rear side needs to be covered, considerable additional expenditure has to be made in terms of method and apparatus. It should be noted here that: in the case of toothbrushes, the transition surfaces between adjacent layers are designed to be as free of play as possible in order to avoid hygiene problems.

The term "bristle carrier" is to be understood as meaning the part of the finished brush which carries the bristles or bristle tufts. The bristle carrier can here be the entire brush body-in the case of a toothbrush a one-piece injection-molded part comprising a handle, a neck and a head-or merely a prefabricated component part of the latter brush body. In the latter case, the bristle carrier is usually a thin plate made of thermoplastic material, which is provided with one or more openings for filling one or more bristles or bristle tufts. After the bristles have been filled and fastened, the lamella-shaped bristle carrier is then inserted into a prefabricated brush body, which has, for example, corresponding recesses for the lamella-shaped bristle carrier. As a further alternative, which is often the case, the sheet-like bristle carriers are encapsulated by injection and the brush body is thus produced from the prefabricated bristle carriers and the rest of the injection.

CH 672579 a5 proposes a method for fastening bristle tufts in a bristle carrier by means of a thin fixing plate. This means that: the bristle tufts are folded and the thin fixing plate is located in the fold region, which presses into the wall of the fixing opening and thereby finally fixes the bristle tufts to the bristle carrier. However, in order to optimally close the opening on the end face or front side of the bristle carrier, so that bacteria and mold cannot colonize there, the bulge on the bristle carrier, which runs around the fastening opening and protrudes from the end face, should be pressed inward. The bristle tufts themselves are not however secured by this deformation of the elevations, but by the fixing elements themselves. The individual bristle tufts are driven one after the other into the bristle carrier by means of a stuffing tool which pushes the folded bristle tuft through a duct. The pipe itself has, on its end side, a heating device which only bears against the bead and melts or plasticizes the bead and then presses it radially inward.

In addition to the above-described possibility for fastenerless fastening of bristles or bristle tufts to a bristle carrier, an additional method has theoretically been created (which, however, could never be carried out in practice) of pushing a bristle tuft into a bristle carrier which has openings and which is preheated. After the bristle tufts have been pushed into the soft bristle carrier, the bristle carrier is pressed by means of a press against its front side, from which the bristle tufts project, so that the soft material surrounding the edges of the opening is pressed and the opening is reduced in cross section. Several schemes are described below for this purpose.

DE 19853030 a1 specifies: the bristle tufts have bristles on their back sides which are melted into thickenings. The bristle carrier has openings into which the cylindrical projections of the heating device are inserted before the bristle tufts penetrate without touching the edges of the openings. By this radiant heat, the inner edge of the opening is locally heated. The bristle carrier reaches a tissue-altering temperature, for example a softening temperature, in the edge region. By increasing the temperature, the holes should be reduced in their cross-section so that the bristle tufts must penetrate into the wall. The bristle tufts with the thickened ends are then pushed into the openings after the removal of the heating device, wherein the thickened portions are larger in cross section than the opening cross section, so that they enter soft regions, i.e. the respective walls, which delimit and enclose the edges of the openings. The front side of the bristle carrier is then deformed, still by means of a punch, so that the material of the bristle carrier is pressed against the bristle tufts and fixes them.

A similar method is known from US 5224763, in which the bristle carrier has a bulge-like opening edge. The edges of the opening are also heated here in such a way that a pin-shaped heating element protrudes into the opening or works with hot air. The opening itself is smaller in cross section than the thickened end of the bristle tuft so that the bristle tuft is fixed therein after penetrating into the wall of the soft opening. The holders for the bristle tufts then press against the heated circumferential elevations, so that additional material can be used to close the openings at the transition to the end side of the bristle carrier.

EP 0355412 a1 discloses a method in which the thickened end of the bristle tuft and/or the edge of the opening in the bristle carrier are heated, the dimensions and temperature being selected such that the edge of the opening, after the thickened end has penetrated, is pushed to the inside and thus surrounds the thickened end and receives it in a form-fitting manner, similar to in a snap connection.

EP 0472857B 1 proposes: the heated punch with the pins is pressed into a plate-shaped bristle carrier made of plastic, which is plate-shaped, so that the pins form openings for receiving bristle tufts. The bristle tufts are then pressed into the stamped, still hot openings, and a melt is present around the thickened portions of the bristle tufts. In addition, the die plate can be pressed against the upper side of the bristle carrier in order to also deform the melt. Particular preference is given here to: on the upper side of the bristle carrier, which is not yet deformed, projections or bulges project, which constitute the material that can be used for the direction of pressing against the opening.

In the method according to DE 3422623 a1, bristle carriers which are designed in the form of plates and have no openings are welded to bristle tufts which are composed of the same plastic as the bristle carriers. The heating tool is moved between the sides of the bristle carrier and the bristle tufts, which have not yet been welded to one another, so that both melt. The bristle tufts are then pressed into the molten material of the bristle carrier.

The present invention, however, relates to a process which differs from the process described in DE 102015111312 a 1. In this case, the bristles or bristle tufts are pushed into the fastening openings beforehand with the usually thickened fastening end. The bristle carrier is then deformed and contracted under the application of pressure and heat to the edges of the fixed opening. In this case, the bristle carrier is only warmed in the front lateral region, to a lower temperature, without reaching the melting temperature. The material displaced by the temperature and pressure closes the fixing opening only on the front side, so that the bristles or bristle tufts can no longer be pulled out. The material is transferred to the outer side of the individual bristles or to the outer side of the bristles of the bristle tuft lying on the outer side. In order to produce bristles with high pull-out forces, sufficient material must therefore be provided in order to close the fastening opening as far as possible toward the front side. For this reason, bristle carriers are provided in which one or more projections or protrusions, which are formed during injection molding of the bristle carrier, project into a fastening opening in the region of the front edge. These projections constitute additional material which is first brought into contact with the mould and then transferred inwards in order to close the fixing opening. Further advantages of these protrusions are: the pressure applied for deformation can be relatively low and the original thickness of the bristle carrier (measured without the protrusions) is not reduced at all or hardly at all when deformed. This means that the adjustment during the clamping and during the compression does not have to be performed as precisely.

Important for high quality brushes, in particular toothbrushes, is: in the case of compression, no excess material is provided which is then pressed into the receiving openings for the bristles or bristle tufts in the mold. This additional material then bears like a thin, non-specifically shaped flange against the individual bristles or against the outer side of the bristle tuft and is convex relative to the front side.

disclosure of Invention

The purpose of the invention is: the known method is improved and a device for carrying out the method is correspondingly specified, by means of which such a collar is avoided.

This object is achieved by a method for producing a brush having a bristle carrier made of thermoplastic material, which has a front side and a rear side and at least one fastening opening, into which at least one bristle with a thickened fastening end made of thermoplastic material is inserted and fastened without fasteners, such that the bristle protrudes from the front side of the bristle carrier, wherein the at least one fastening opening is delimited by an inner side and has an end-side edge on the front side which surrounds the fastening opening, characterized by the following steps:

a) Providing a bristle carrier which, in the region of the end-side edges, has a transition edge to the inner side, which is at least partially beveled on the circumference of the transition edge, wherein the fastening opening and the transition edge are formed when the bristle carrier is injection molded,

b) Receiving the at least one bristle in the receiving opening of the mould part,

c) While the at least one bristle is still in the receiving opening, the thickened fastening end of the at least one bristle moves the at least one bristle into a fastening opening in the bristle carrier formed during the manufacture of the bristle carrier,

d) The spacing between the mold portion and the bristle carrier is reduced such that the mold portion contacts the bristle carrier,

e) The front side of the bristle carrier is brought to a temperature below the melting temperature of the bristle material and/or of the bristle carrier material, in particular in the case of c up to 85% of the respective melting temperature of the bristle material and/or of the bristle carrier material,

f) The mold part exerts a pressure on the heated bristle carrier and deforms the bristle carrier in the region of the end-side edge surrounding the fastening opening with a reduced cross-section of the fastening opening, so that the at least one bristle is inserted into and fastened in the fastening opening, wherein the material of the bristle carrier in the region of the edge and of the inner side is pressed laterally into the fastening opening and into the region of the transition edge and against the at least one bristle, and

g) The spacing between the mold portion and the bristle carrier is enlarged to pull the at least one bristle out of the receiving opening.

The warming of the bristle holders can be performed before or during the narrowing of the spacing between the mold sections and the bristle holders or after the first contact between the mold and the bristle holders. The order of steps d) and e) therefore need not be sequential.

the idea of the invention is that: the material that closes the fastening opening towards the front side and fastens the bristles or bristle tufts to prevent the pulling-out is provided only by the brush body between the front side and the rear side and is thus provided without shaped projections, wherein the chamfer on the transition edge serves as a buffer space into which the material can enter without protruding as a collar relative to the closing surface formed by the front side. A small amount of material is thus available in the region of the chamfer to be pushed inwards, so that material of the deeper regions in the fixing opening can move axially outwards. In contrast to the prior art, which provides additional material, the present invention provides for intentional material reduction at the transition edge. Although the bristle carrier must therefore be pressed precisely, the material reduction at the mouth of the fastening opening and the space obtained thereby allow greater tolerances in the clamping of the mold than would be the case without these bevels.

The chamfer can extend along the entire circumference of the transition edge and optionally in this case extend with the same cross section, that is to say with the same shape and the same dimensions, along the entire circumference of the transition edge, which is optimal for the production of an injection molding tool.

As an alternative to this, however, the chamfer can also have different cross sections along the periphery of the transition edge, which cross sections can be optimized in such a way that the material is pressed inward to different extents in different sections and thus more or less damping space is required.

For example, the chamfer can have different cross sections along the circumference of the transition edge, but these cross sections start at the same axial depth of the fastening opening. The axial depth is measured from a front side of the bristle carrier adjacent the chamfer. In general, this is not limited to this embodiment only, the front side having a planar, convex or concave form. In the case of a convex or concave form, the depth is measured from the envelope of the front side.

As has been proven in practice, a chamfer starting in the fixing opening at a depth of at least 0.1mm and at most 0.5mm, in particular at most 0.35mm, from the front side of the bristle carrier adjoining the chamfer is sufficient.

The chamfer requires only a minimum radial width of 0.1mm and a maximum radial width of 0.5mm, in particular a maximum radial width of 0.35 mm.

The chamfer can be formed in cross section partially by a chamfer and/or a circular arc, in particular a radius. These simple geometries simplify the production of the injection molding tool and, on the other hand, are absolutely sufficient to prevent the material from being pressed out of the fastening opening, as has been proven in tests.

As already explained above, the front side of the carrier can be a flat, convex or concave arched surface.

In particular, a plurality of fastening openings are provided, wherein at least some of the fastening openings each have a chamfer and the chamfers of the fastening openings are different. What is also achieved by this method is: the fixing openings are treated separately and are tailored in order to achieve, on the one hand, a high pull-out force and, on the other hand, an optimum appearance of the brush.

In the method according to the invention, the at least one fastening opening of the bristle carrier is not pressed completely, but only in the region of the mouth, that is to say of the end edge surrounding the fastening opening. In this case, the at least one fixing opening of the bristle carrier is reduced in cross section only up to the beginning of the thickened fastening end of the bristle or bristle tuft, in particular only up to a depth of at most 1 mm. The rest of the fixation opening retains its original shape.

The bristle carrier is pressed in such a way that the material of the bristle carrier in the edge region and in the region of the inner side of the fastening opening is pressed laterally into the fastening opening and in the region of the transition edge without protruding outward via the envelope formed by the front side of the bristle carrier.

The chamfer does not constitute a lead-in chamfer either, since a lead-in chamfer is not necessary at all in this position. This is particularly the case: the thickened fastening end has a rounded or beveled underside with which the bristles or bristle tufts are introduced into the fastening openings beforehand. This rounded or chamfered underside is usually formed when the bristles of the bristle tufts are melted.

The bristle tufts are inserted with their thickened fastening ends into the fixing openings in advance such that they do not come into contact with the chamfer of the fixing openings.

The lateral dimension of the thickened fastening end is in particular smaller than the lateral dimension of the correspondingly configured fastening opening in the base region of the fastening opening. Thereby having lateral clearance that allows the bristles or bristle tufts to be quickly inserted into the fixed openings. In addition, the shape of the bristles or bristle tufts is not impaired, as can be the case when the bristles or bristle tufts are pressed and compressed on their "roots", that is to say on the thickened fastening ends. By the mentioned peculiarities, the orientation of the bristles or the parallel orientation of the bristles of a bristle tuft is more reliable.

In contrast to the prior art, the brush body is injected together with the at least one fastening opening, i.e. the fastening opening is not formed by pressing in a hot punch. The inner side of the fastening opening is provided with a so-called draft angle, which may be, for example, at most 2 °. Due to this demolding slope, the demolding of the bristle body from the injection molding mold is simplified and can also be effected in part. However, this draft is not a component of the chamfer and does not belong to this chamfer.

The individual bristle tufts or all the bristle tufts can be inserted perpendicular to the adjoining front side and can be inserted into their fastening openings.

As an alternative to this, there are also bristles or bristle tufts which engage obliquely in the fixing openings with respect to the front side. The invention provides in this case that: the chamfer on the transition edge is formed larger on the side inclined toward the bristle or bristle tuft than on the remaining circumference of the transition edge. As an alternative to this, there may be no chamfer at all on the side remote from the bristles or bristle tufts and a chamfer in the remainder of the transition edge circumference. Since, in the region of the front edge of the fixed opening, due to the inclined position of the bristles or bristle tufts, not as much material has to be molded on the side of the bristles that is inclined thereto, there is an increased risk that: the material is transferred out of the fixed opening. An additional or larger buffer space formed by the chamfer is therefore required in this region.

During the application of pressure to the bristle carrier, the back side of the bristle carrier should be actively cooled in order to keep it stable and not allow deformation in this back side region during squeezing of the bristle carrier.

bristle carriers typically have a plurality of fixed openings. One embodiment of the invention provides for: the edges of these fixed openings are not provided with a projection that is raised relative to the front side of the bristle carrier.

It goes without saying that such a projection can be provided locally, in particular where the fastening openings are particularly adjacent to one another and there is only one thin web, as an alternative.

In the method according to the present invention, the front side of the bristle holder is preferably heated. The front side is heated to a temperature below the melting temperature of the bristle material and/or bristle carrier material, in particular up to 85% of the respective melting temperature of the bristle material and/or bristle carrier material measured in ° c. The mold portion exerts a pressure 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 performed by a heated mold part. If, as is the case in the preferred variant, the end sides of the mold parts are in contact with the front side for several seconds, the temperature of the end sides of the mold parts also corresponds to the temperature on the front side of the bristle carrier, so that these temperatures correspond to one another. This means that: the end faces of the mould parts are heated to a temperature below the melting temperature of the bristle material and/or bristle carrier material, in particular up to 85% of the respective melting temperature of the bristle material and/or bristle carrier material measured in ° c.

Although it is preferred that the above-described method steps are carried out in the above-described order, this is not mandatory. For example, the front side of the bristle carrier can be heated first and then the spacing of the mold sections from the bristle carrier can be reduced, or both steps can be performed simultaneously or partially simultaneously.

The change in spacing is achieved by a relative movement of the mould part and the holder, i.e. the mould part is movable, for which the holder is stationary or vice versa or both the mould part and the holder are moved.

When "at least one bristle" is mentioned hereinafter, this then means: in this case, both a single bristle fitting in a receiving opening and a fastening opening, a single bristle tuft with a plurality of bristles fitting in a receiving opening and a fastening opening, and a plurality of bristle tufts fitting in their receiving openings and fastening openings are meant, so that the invention is not limited to the fastening of individual bristles or individual bristles spaced apart from one another. Although bristle tufts are mentioned in the following text in addition for easier readability, the invention can be used in general both for bristle carriers having one or more individual bristles and for bristle carriers having one or more bristle tufts or a combination thereof. Furthermore, this relates to both the method claims and the product claims.

In the following, a number of modifications which per se form the invention are described, but which also form an optimization by combining with one another. It is to be emphasized that: the device described later can also have the features described in connection with the method, wherein only the control system is programmed accordingly.

As a result of the heating, the holder accommodating the bristle holder can be heated, possibly during operation, for example by radiation. Furthermore, the pressure can be applied to the bristle carrier for so long that it is overheated deeper and farther from the front side and is thereby also deformed in these deeper regions, as a number of tests have shown. To prevent this, according to a variant of the invention, the back side of the bristle carrier is actively cooled during the application of pressure to the bristle carrier. A separate cooling device is thus provided, for example by liquid cooling. Whereby the volume range of the bristle carrier, in which there is a sufficiently high temperature for shaping during the application of pressure, becomes adjustable within a narrow range. Furthermore, a protective region is realized within the bristle carrier by the cooling device, in which no deformation occurs.

the back side of the bristle holder is actively cooled during the application of pressure. In this case, it is preferably ensured that: the bristle carrier is warmed up to 25 c during the process.

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

cooling can be effected not only on the back side of the bristle carrier, but optionally also at least over a section of the side surface of the bristle carrier. The side surfaces are the surfaces that connect the front and back sides of the bristle holder. By cooling, it is precluded: when the bristle carrier is squeezed between the front and back sides, the side surfaces plastically deform laterally outward. For this purpose, the holder can have receiving recesses for the bristle carriers, which are configured to be complementary to the bristle carriers and ensure that the back and side faces rest against the holder.

the bristle carrier is preferably heated by the heatable tool part only after the at least one bristle has been inserted.

The mold sections can be heated by integrated resistance heating or by heated adjacent parts which temporarily contact the mold sections beyond the contact surfaces touching the bristle carrier and transfer heat to the mold sections upon this contact. The mold sections are heated to a predetermined temperature in a controlled manner not by "random" heating of adjacent, more or less hot components, but via heating devices which are assigned only to the mold sections. During the application of pressure to the bristle carrier, pressure is applied in a device while the bristle carrier is in contact with the mold section on the front side and the holder on the back side. In order to apply the pressure, the device is in particular locked (auf block fast). This means that: there is no spacing between the holder and the mould part, since they are in contact with one another at the end sides. This contact is preferably made in the interface between the holder and the mould part, all over and around the enclosed bristle carrier. Whereby the cavity between the holder and the mould part configured for accommodating the bristle carrier is sealed in said interface. Here, material without the bristle holder can migrate into the gap and then form a burr on the finished bristle holder.

As has surprisingly been demonstrated in tests, the stability and precision of the bristle carrier and of the orientation of the at least one bristle, in particular of the bristle tufts, can be increased if the device is not detached and the bristle carrier is moved away shortly after a so-called action time (time during which a pressure is exerted on the bristle carrier between the front side and the back side). Although this is very disadvantageous with regard to cycle time, a ventilation gap is produced between the front side and the mold part after the action time has elapsed. This means that: the mold sections and the holder are moved slightly away from each other. In this case, the device is neither completely separated nor placed in a position in which the bristle carrier is or can be removed. The bristle carrier, including at least one bristle, preferably one or more bristle tufts, thereof, is inserted into a resting phase, in which the ventilation gap in the device serves to cool the front side. In this rest phase, the back side continues to come into contact with the holder, if necessary, depending on the shape of the holder, together with the side surfaces, which produces a shaping effect.

the predetermined rest phase should last for at least 1 second, in particular at least 1.5 seconds. Preferably no further movement between the holder and the mould parts takes place during this time. As an alternative, a slow opening movement can be performed.

Particularly advantageous are: the at least one bristle, in particular one or more bristle tufts, is held in its configured receiving opening throughout the rest phase. The receiving openings retain the shape of the bristles or bristles of one or more bristle tufts during said resting phase. Thereby stabilizing the area surrounding the fixation opening. It is apparent that the internal stresses are eliminated.

the ventilation gap should have a height of at least 1mm, measured in the direction of movement of the device (the direction of movement between the holder and the mould parts when the device is opened and closed).

As already mentioned, the ventilation gap can preferably be kept constant during the stationary phase.

Alternatively, cooling air may be blown through the vent gap toward the front side of the bristle carrier. The stationary phase can thereby be shortened in time.

Further features of the invention are: after an advancing movement of the mold part and the bristle carrier relative to one another, which ends with the arrival of the closed position of the device, a pressure is exerted on the bristle carrier in the closed position for a predetermined holding time. Although the aim of the effort is to keep the cycle time as short as possible, this particular feature according to the invention does not allow the device to be closed and immediately reopened, as is usually the case when extruding, shaping or blanking objects. The pressure need not be constant during the holding time because it depends on the impedance of the bristle holder. The pressure therefore decreases as the deformation of the bristle carrier increases.

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

As maximum holding time, 3 seconds, in particular a maximum of 2.5 seconds, has proved to be optimal. No longer is necessary.

The bristle carrier can already be heated on the front side during the holding time, in particular during the entire holding time, however optionally during the feed movement. If heating is already carried out during the feed movement, cycle time can be saved. That is, heating of the front side, for example by radiation, also already takes place during the feed movement. Once the front side is in contact with the heated mold portion, the front side and bristle holder are heated and brought to temperature during subsequent shut down of the apparatus.

The duration of the action of the pressure on the bristle carrier is determined by the sum of the holding time and the period during which the front side is initially in contact with the die portion and at the same time the back side is in contact with the holder and is compressed until the fully gathered position is reached. This action time should be at least 4 seconds, in particular at least 5 seconds.

As maximum action time, 15 seconds, in particular a maximum of 10 seconds, have proven to be a limit.

Here, the holding time, during which the bristle carrier is squeezed, is preferably less than the above-mentioned time period during which the bristle carrier is gathered. This gathering and compression is performed at a very slow feed speed of the holder relative to the mold sections. In particular, this period is at least 3 seconds, in particular at least 4 seconds.

The test shows that: the holding time is at most 50%, in particular at most 40%, of the above-mentioned period of time when gathering takes place, during which period the bristle carrier is compressed.

To shorten the cycle time it may be meaningful to: the front side of the bristle carrier has been heated by other means and not only by contact with the mold sections. The bristle carrier can be preheated. For example, hot air can be blown onto the bristle carrier on its front side when it has been fitted in the holder or it can be influenced for a short time by a heat source (e.g. radiant heat) which does not form part of the mold. This can take place during or temporally before the feed movement of the mould parts to the holder. This allows, for example, the bristle carrier to be heated during the adjusting movement of the holder/mold section or before the mold section is moved laterally closer to the holder. The subsequent heating time by contact with the mould parts can thereby be shortened.

Further features of the invention are: the free end of the at least one bristle is supported in the device at the end side. This support should fix the axial position of the one or more bristles of one or more bristle tufts relative to each other within the same bristle tuft or within a plurality of bristle tufts. In the case of a plurality of bristle tufts, the brush should have a sawtooth shape at the ends of the bristle tufts, for example, as viewed from the side. Other selection possibilities are: one bristle tuft is serrated, converging toward the apex, or tapered.

It is desirable that: this support, which serves as a stop or as a shaping tool, should also be active during the application of pressure to the bristle carrier, so that during this time no movement of the bristle, bristles or bristle tufts is permitted. However, it has been demonstrated that: it is beneficial to have this support removed at least during the application of pressure to the bristle carrier, and preferably also during the feed motion prior to the application of pressure or after the device contacts the front and back sides of the bristle carrier with the mold or holder. This means that: at least in the final phase during the application of pressure, optionally also before the removal of the embedded support during the entire time of the application of pressure. The introduction of a minimum pressure into the bristles by the support at least in the final phase of the deformation process or the entire phase of the deformation process can lead to deformation of the bristles or to: the bristles stand obliquely or are oriented non-parallel to each other, even if not within one bristle tuft.

In this connection it may be appropriate to: the cross section of the at least one bristle and the cross section of the receiving opening provided in the mold part are matched to one another in such a way that the at least one bristle/the at least one bristle tuft is clamped in the receiving opening and can be positioned axially by this clamping. That is, when the bristle or bristles of a bristle tuft are oriented axially, they are clamped in the receiving opening and are thereby positioned axially. It goes without saying that this clamping is only a minimum clamping which normally allows slippage during the axial orientation carried out before. However, due to the self-weight of the bristles/bristle tufts or due to the inertia during the movement of the device, no active, unintended sliding of the bristles/bristle tufts in the receiving openings occurs.

Similarly to this in the fastening without a mount, which is used in practice, the at least one bristle or the entire bristle tuft can, by thermally deforming the bristle material, obtain a thickened fastening end in such a way that it is heated above the melting temperature. In the case of using a bristle tuft, the bristles of the bristle tuft are united with each other by thermal deformation. However, it is not always the case here that adjacent bristle tufts are united with one another, but rather that each bristle tuft has a thickened fastening end with which it was previously inserted into the fastening opening.

The shaping is carried out outside a fixed station carrying out at least steps c) to f).

The material of the thickened fastening end portion is therefore preferably already solidified when the respective fastening end portion is inserted into the fixing opening.

By means of the invention, it is not only possible to fasten the bristle tufts in the fixing openings by deforming the opening edges, but also to fasten prefabricated, so-called elastomeric cleaning elements (for example consisting of thermoplastic) in the fixing openings, which cleaning elements are several times thicker than the normal filaments of the bristle tufts. These cleaning elements are used both for improving the cleaning effect and, in the case of toothbrushes, for massaging the gums. Furthermore, the cleaning elements do not necessarily have to have a pin shape, but can have any cross section, in particular an elongated, curved, cross-shaped or rounded (circular or oval) shape and a corresponding ring shape with a central opening.

The at least one fixation opening may be filled with individual bristles prefabricated from an elastomeric material, in particular a thermoplastic elastomer (TPE). The individual bristles are secured in the fixed openings by deforming the bristle carrier.

Preferably, the individual prefabricated bristles have a maximum wall thickness, measured in cross section, of more than 0.6mm, in particular more than 0.9 mm. For example, the largest wall thickness measured in the longitudinal direction in the case of a rectangular cross-sectional shape.

Alternatively, the individual prefabricated bristles can have thickened fastening ends with which the bristles are inserted into the fastening openings and which are surrounded by deformed edges of the fastening openings of the bristle carrier. The thickened fastening end is produced when the individual bristles are manufactured, and not, for example, by pressing in and elastically deforming the bristles by deforming the edge of the fastening opening. However, as alternatives it is possible: when the bristles are sufficiently thick and the edges are pressed into the elastomeric bristles so that the fastening end is then thickened by the extruded material, work is performed without the thickened fastening end.

The thickened fastening end has for example the shape of a flat cylinder and/or the individual prefabricated bristles are multi-component injection molded parts. In this connection, the thickened fastening end can be composed of a material which is different from the outer surface of at least the individual preformed bristles outside the fixing opening, preferably a harder material such as polypropylene. Preferably, the fastening end is even stiffer than the whole rest of the individual prefabricated bristles. By means of said harder fastening end, the bristles fit better in the fixing openings.

usually, a plurality of fastening openings are provided in the bristle carrier, wherein at least one, preferably a plurality of fastening openings are provided only with one/a plurality of individual prefabricated bristles. At least one further, preferably the remaining, fixed openings are provided with prefabricated bristle tufts, in contrast, so that the brush has a mixed form comprising conventional bristle tufts and thicker elastomeric cleaning elements.

The individual bristles, viewed in side view, project with their free ends, for example at least as far as the free ends of the bristle tufts, and are therefore no shorter than the bristle tufts. It would be beneficial to: the elastomeric cleaning elements, that is to say the individual bristles, are even longer than the bristle tufts and project beyond their ends on the front side. Of course the elastomeric cleaning elements may also be shorter than the bristle tufts.

Further features of the invention are: the wall delimiting the fastening opening in the bristle carrier is deformed after the deformation only from the front side to the upper part of the thickened end. The fastening end can also be, for example, a thickened end or a thickened fastening end of a bristle tuft, in which the bristles merge into one piece with one another. It is desirable that: the entire fixing opening rests as tightly and as free as possible against the fastening end in order to completely prevent movement of the bristles or bristle tufts in any direction. However, the invention develops a new way. The fastening end is not completely pressed but has a certain free space inside the fixing opening. The position of the at least one bristle, however in particular of the bristles within a bristle tuft, is thereby made more precisely adjustable. If, for example, the thickened end of a bristle tuft is completely compressed, the bristles attempt to separate from one another and no longer have a mutually parallel orientation.

For example, the deformation should only take place in the edge region of the fixing opening, that is to say in the region of the wall segment which is located in the mouth region of the fixing opening.

For the finished brush, the walls of the fixed openings do not grip and/or deform the fastening end of the bristles or of the at least one integral bristle tuft over a depth of at least 1mm, in particular at least 0.8 mm. This region, in which no clamping and/or deformation of the fastening end takes place, starts at the bottom of the fastening opening and continues in the direction of the front side of the bristle carrier over at least 0.8 mm.

It is even possible to have a space between the wall and the at least one bristle/bristle tuft, in particular in the region of the bottom of the fixing opening or in the region adjoining this bottom.

As already mentioned above, the at least one bristle or the at least one integral bristle tuft can have a thickened fastening end. The edge of the fixing opening, i.e. the region of the wall in the region of the mouth opening to the front side, is deformed. In this region, the edge is shrunk so that the fastening opening is enlarged toward the bottom and the thickened fastening end is clamped in the pull-out direction from behind by the deformed edge, so that the bristles/bristle tufts are prevented from being pulled out by the edge which acts as a stop.

The narrowed "neck" of the fixing opening, which is formed by deformation in the vicinity of the mouth, that is to say the deformed edge of the fixing opening which clamps the thickened fastening end from behind, may have, for example, an axial extent of 0.5 to 1.3mm, in particular 0.6 to 0.9mm ("axial" in connection with the invention means always in the direction from the front side to the back side or from the back side to the front side). This is a very small height.

Brushes, in particular toothbrushes, produced by the invention can have a very small thickness in the region of the bristle carrier. Whereas toothbrushes so far have a thickness of more than 4mm in the head region, a thickness of less than 4mm can be achieved by the invention while the holding force for the bristles or bristle tufts is better than in the prior art. Furthermore, according to the invention it is possible to position bristle tufts, also larger bristle tufts, very close to the edge of the front side, which was not possible hitherto.

The bristle tufts can also be caused to shrink in cross section by deformation of the edges of the fixed opening. This means that: the bristle tufts are fastened in the fixed opening and the edge of the fixed opening is deformed such that the edge compacts the bristle tufts in the region where the bristles are arranged side by side. The region in which the bristles are arranged next to one another preferably adjoins directly the fastening end formed by the bristles melted together. The bristle tuft thus acquires a smaller cross-section after deformation and shrinkage of the fixed opening than the bristle tuft has after insertion into the fixed opening.

Preference is given to: the bristle tufts are compacted by at least 3%, in particular by at least 5%. This compaction is defined by the difference in cross section, that is to say the cross sectional area, of the receiving opening in the mould part and of the deformed fixing opening in the edge region, that is to say in the region of the mouth of the fixing opening to the front side.

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

preferably, the fixing openings, before their deformation, have an interference of less than 0.2mm only in the lateral direction with respect to the maximum cross section of the fastening end of the bristle tuft/bristle, in order to be able to insert the fastening end into the fixing opening without difficulty. After the deformation, a form closure is produced by the constricted edges of the fastening opening, in which form closure the edges can be only 0.1 to 0.3mm narrower in cross section than the maximum cross section of the fastening end. This minimum excess is sufficient to achieve superior pull-out values (auszugswart).

The invention can also be realized in that: the bristle carrier is processed with the back side already coated with elastomer. When the bristles/bristle tufts are inserted into the fixing openings on the front side, the elastomer has been sprayed on the back side of the bristle carrier. The holder in which the bristle carrier is received when pressure is applied has a recess. The recess is configured to: which houses a bristle carrier having an elastomer on the back side. The recess can in particular be configured to complement the shape of the bristle carrier provided with the injection encapsulation. Since the elastomer is mostly designed as a tongue scraper with raised elevations in the case of toothbrushes, the holder has correspondingly complementarily configured recesses for these elevations.

However, the depth of the recess is preferably designed such that: which is used to contain a volume of elastomer that is less than the uncompressed volume of the elastomer. The volume in the receptacle is thereby adapted to the actual volume of the compressed elastic material when the deformation pressure for the edge of the fastening opening is applied. Since the elastomer is softer than the bristle carrier, it is necessary to prevent the pressure from becoming too low due to the intervening elastomer.

The counter force exerted by the holder upon deformation can be introduced into the front portion of the bristle carrier entirely via the elastomer. It is not necessary to forcibly bring the back side of the bristle carrier into direct contact with the holder without intervening elastomeric material in order to introduce a counter force into the bristle carrier.

The aforementioned various selection possibilities of the method according to the invention may have the following optimized steps: :

The mold part is heated so that its end face lying opposite the bristle carrier is heated to a temperature below the melting temperature of the bristle material and/or the bristle carrier material, in particular below 85% of the respective melting temperature of the bristle material and/or the bristle carrier material in ° c. The mold section is moved relative to the bristle carrier such that the mold section contacts and heats the bristle carrier.

According to a further aspect, the method according to the invention is used for producing a brush having a bristle carrier with at least one fastening opening and at least one bristle which is inserted into the fastening opening and fastened therein without fastening means, wherein the bristle carrier and the at least one bristle consist of a thermoplastic which may be the same or different, and is further developed, according to a further aspect, by the following steps:

Heating the end face of the mold part opposite the bristle carrier to a predetermined temperature in the range between ambient temperature and 210 ℃, in particular 150 ℃;

The mold portion is moved relative to the bristle carrier such that the mold portion contacts the bristle carrier and heats it to a predetermined temperature without melting the bristle carrier and the at least one bristle.

The thermoplastic is preferably selected from the group comprising in all embodiments: polyesters, in particular polyethylene terephthalate (PET), preferably BR003 and polybutylene terephthalate (PBT), polypropylene (PP), Polycarbonate (PC), Polyamide (PA), polyvinyl alcohol (PVA), Polyethylene (PE), acrylonitrile-butadiene-styrene copolymer (ABS) and styrene-acrylonitrile copolymer (SAN). Both homopolymers and copolymers with the thermoplastic mentioned can be used.

According to the invention, the bristle carrier and the at least one bristle inserted into the mold part should not melt when the mold part is in contact with the bristle carrier. The predetermined temperature is preferably at most 85% of the melting temperature of the thermoplastic. Damage to the bristles and/or bristle holders can thereby be reliably avoided.

Preferably, the predetermined temperature is in the range between 30 ℃ and 150 ℃, particularly preferably between 60 ℃ and 140 ℃, in particular between 90 and 130 ℃ or between 100 and 115 ℃.

The predetermined temperature is further preferably above the glass transition temperature of the thermoplastic. This results in sufficient deformability of the thermoplastic.

The method according to the invention is fundamentally different from the prior art in that it firstly only provides for the bristles, the bristle tuft or the bristle tufts to be fastened without a fastening means. The fastening opening itself is prefabricated, i.e., a heated punch is not used here to press a hole into the bristle carrier, but rather a receiving opening is already produced during the injection molding of the bristle carrier. Furthermore, the receiving opening is not first heated on the inside and the inside edge of the opening is thereby softened, so that the bristles or bristle tufts are pressed into the soft wall of the receiving opening. Rather, the bristles or one or more bristle tufts are preferably first inserted into the receiving openings and only then is the bristle carrier heated, but not melted, on its front side opposite the mold part. The operation is carried out below the melting temperature of the bristle material and/or bristle carrier material, wherein the heating takes place by means of the mould parts in which the bristles or bristle tufts are fitted, and is in no way heated by means of separate, purely heated tools which have to be removed again when the bristles or bristle tufts are introduced. Such heating by the mold part itself, in which the bristles or bristle tufts are fitted, is therefore neither relevant nor suggested by the prior art, since in the prior art the bristle tufts should penetrate into the heated soft wall of the bristle carrier and must therefore have a high inherent stability in order to be able to continue to conduct the pressing-in force applied to the bristle tufts. It has been possible to press the fixed end into the softened wall of the bristle carrier only by the pressing-in force applied to the back flank of the bristle tuft and by the inherent rigidity of the cold bristle tuft. In addition, the heating is done by contact with the bristle carrier by the heated mold portion itself, rather than by non-contact heating as is predominantly prevalent in the prior art. This enables, on the one hand, a faster energy transfer and, on the other hand, the device can be designed with fewer components.

The bristle carrier is heated throughout the deformation process to a temperature below the melting temperature, preferably to a temperature significantly 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 degrees kelvin and in the case of bristle carrier materials having a glass transition temperature of 300 degrees kelvin or more. In the case of bristle materials having a glass transition temperature of less than 300 degrees kelvin, the bristle carrier is heated to a temperature of at most 50% above the glass transition temperature, calculated in degrees kelvin, throughout the deformation process. The bristle carrier is preferably heated to a temperature above the glass transition temperature.

The invention and its advantageous variants described above and in the following provide in particular for polypropylene to be used as bristle carrier material, several groups of which have a glass transition temperature of less than 300 degrees kelvin and others of which have a glass transition temperature of more than 300 degrees kelvin. Other preferred bristle carrier materials are PET, PBT, PA, ABS, SAN and PC. These bristle carrier materials all have a glass transition temperature greater than 300 degrees kelvin.

The glass transition temperature can be determined, for example, by Dynamic Mechanical Thermal Analysis (DMTA). The upper end of the melting temperature range is considered to be the melting temperature in the partially crystalline thermoplastic. The melting temperature can be determined, for example, by Differential Scanning Calorimetry (DSC). In the case of amorphous thermoplastics, the transition to the yield or processing range (Flie. beta. -oder Verarbeitungsbereich) is considered to be the melting temperature.

In order to make the timing for manufacturing the bristle carrier relatively short, one embodiment of the present invention provides: the mold section is heated prior to its contact with the bristle carrier. It goes without saying that this has the disadvantage: the bristles or bristle tufts themselves are already heated at the same time, which is undesirable in the prior art, since the bristle tufts should be pressed into the soft wall. In accordance with the present invention, the mold section can be heated to its predetermined maximum operating temperature prior to its contact with the bristle carrier.

in addition, the invention provides in one embodiment of the invention that: the plastic of the bristle holder has a melting temperature that is lower than the melting temperature of the bristle or bristles. However, there are also brushes in which the bristle carrier material is the same as the bristle material, for example polypropylene and PA.

As already explained, the heating of the bristle carrier should take place only after the insertion of the at least one bristle by the mold part and preferably only by contact. It goes without saying that a slight temperature rise occurs when the bristle carrier approaches a warm or hot mold part, which temperature rise is, however, absolutely negligible and only occurs on the immediately adjacent surface.

However, if the feed movement should last for a long time, then as a further alternative: the mold section heats the bristle carrier in the region of the contact surface with the mold during the feed motion of the mold section to a temperature which is below the melting temperature of the bristle carrier material and preferably equal to or greater than the glass transition temperature of the bristle carrier material. Alternatively or additionally, the bristle carrier can also be heated to the aforementioned temperature while the mold sections are in contact with the bristle carrier.

According to one embodiment of the present invention, the heating of the bristle carrier to the predetermined and aforementioned temperature or temperature range should be 0.25 to 0.5mm below the surface of the bristle carrier facing the mold portion (front side) until the end of the deformation process. Since the mold portions press against the bristle carriers for a longer period of time and heat them at the same time, the heat energy also moves deeper into the interior of the bristle carriers. It is thus not necessary to heat the mould part to a great extent already when this mould part is initially in contact with the bristle carrier, it being sufficient to achieve this heating during the feed movement and the action time (contact time).

In a first phase of the feed movement relative to the bristle carrier, the die part can heat the bristle carrier at least in the region of the edge surrounding the fastening opening, preferably however in the entire contact region, to a temperature above a limit temperature which, when working with bristle carrier materials having a glass transition temperature of 300 kelvin or more, corresponds to 60%, in particular 80%, of the glass transition temperature of the bristle carrier material in ° c. This relates in particular to bristle carrier materials such as polypropylene variants (polypropylenovariante) having a glass transition temperature of 300 degrees kelvin or more, PET, PBT, PA, ABS, SAN and PC. Alternatively, when working with a bristle carrier material having a glass transition temperature of less than 300 degrees Kelvin (this is particularly the case when using polypropylene variants having such a low glass transition temperature), the limiting temperature is ambient temperature. The heating is carried out before the mould parts deform the edge and press the edge against the at least one bristle in the second phase of the feed movement.

The bristle carrier material may be heated, particularly to a temperature in the range between the glass transition temperature and about 85% below the melting temperature of the thermoplastic, calculated as ° c. This temperature is preferably in the range between 30 ℃ and 210 ℃, particularly preferably between 60 and 140 ℃, preferably between 90 and 130 ℃ or 100 and 115 ℃ depending on the thermoplastic material used.

As has been proven in tests, before the mold part is brought into contact with the bristle carrier, in particular before the bristle carrier is heated at least in the region of the edge surrounding the fastening opening, preferably in the entire contact region, to a temperature which is above a limit temperature which, in the case of operation with bristle carrier materials having a glass transition temperature of 300 degrees Kelvin or above, is 40%, in particular 20%, below the glass transition temperature of the bristle carrier material in ° C (this relates in particular to the bristle carrier material, such as the polypropylene variants having a glass transition temperature of 300 degrees Kelvin or above, PET, PBT, PA, ABS, SAN and PC), or which, when using a bristle carrier material having a glass transition temperature of less than 300 degrees Kelvin, is moved into the receiving opening, I.e. in particular polypropylene variants having such a low glass transition temperature, are operated at ambient temperature. The edge of the mounting opening is at least the outer edge on the front side of the bristle carrier.

Other variants of the invention provide for: before the edge of the fixing opening is heated to a temperature of at least 30 ℃ above ambient temperature, in particular before the edge of the fixing opening is heated to above ambient temperature inside the fixing opening by the mold part, the at least one bristle or the bristle tuft is first moved into the receiving opening. This means that: in the last-mentioned variant, unlike the prior art, in which a heatable pin is inserted into the opening in order to heat the inner edge of the opening, that is to say the wall delimiting the opening, up to the hole bottom, the edge inside the opening is not heated significantly.

The deformation should be such that the edge of the bristle carrier is pressed over the entire circumference in the transition region to the front or end face of the bristle carrier against the outer bristles of the fastened bristle tufts, so that a compression of the bristle tufts occurs. It goes without saying that the manner and extent of the compaction depends on the cross-section of the bristle tufts. In the case of a toothbrush, the cross section of the fixing opening is reduced by, for example, a maximum of 0.3mm, preferably a maximum of 0.15 mm.

Preferably, no heating of the opening wall also relates to the remaining embodiments. This means that, as an alternative, the edge is heated to a predetermined limit temperature or temperature generally only in the region of the front side, i.e. in the transition region of the front side to the fastening opening, while the ambient temperature in the opening itself remains substantially constant during the period in which the mold part is not in contact with the bristle carrier.

A preferred embodiment of the invention provides that: the mold portion is also heated throughout the contact area of the mold portion with the bristle carrier, not just in the linear or dotted areas around the edge of the attachment opening. This has the following advantages: the entire contact area and thus the entire adjoining material area of the mould part can be used by the mould part for moving and deforming this material area by the high pressure applied. Here, it is additionally advantageous: the mould part even contacts the entire end side of the bristle carrier facing the mould part, i.e. its front side, but at least contacts and exerts a pressure on at least 70% of the area of the front side. In the prior art, a flange is realized by a raised ridge on the finished bristle carrier, which flange constitutes the sole material, heated and deformed. The invention differs significantly from it, however, in that the section of the end-side edge of the bristle carrier remote from the fastening opening is heated and simultaneously deformed.

The back side of the bristle carrier should not be heated by the mold part during the fixing, so that only the front side facing the mold part is actually heated and deformed, while the back side constitutes a plate-like, stable structure, which can be referred to as the base of the bristle carrier. And thus does not deform or change in shape of this portion of the bristle holder during the application of pressure.

The mold portion may also heat the bristle carrier at the end side at least during the entire time it exerts pressure on the bristle carrier. In the present invention, this is not the case if the bristle carrier is briefly previously heated and then the bristle tufts are moved rapidly into the heated material sections of the bristle carrier, as is the case in the prior art in which the bristle carriers (into which the bristle tufts are then pushed) are previously heated.

The plastics used in the present invention are, for example, copolyesters, in particular Eastart BR003 (having a melting temperature range of 230 to 280 ℃), polypropylene, in particular homopolymers such as PPH5042 having a melting temperature of 165 ℃, polycarbonate, polyamide, polyvinyl acetate or polyethylene. If these materials have a glass transition temperature, here 300 degrees Kelvin, that exceeds ambient temperature, energy should be placed into the bristle holder via the mold portion. This is also beneficial in the case of materials with a glass transition temperature below ambient temperature. However, according to a variant of the invention, it is sufficient in the case of such a material for the bristle carrier even if the bristle carrier is not heated by the mold part. Then shaping is effected at ambient temperature only via pressure of the mold sections on the bristle carrier.

The bristle carrier material is advantageously heated to the following temperatures using the method according to the invention and by means of the device according to the invention which will also be explained below:

Bristle carrier material	Melting temperature [ deg.C ]	Glass transition temperature [ deg.C ]	Process temperature [ deg.C ]
				Polypropylene	160 DEG to 170 DEG	-10 ° to 0 °	＜136°
PET	260°	70°	＜120°
				PBT	220°	47°	＜95°
PA	200 to 260 DEG	50 to 60 °	＜98°
				ABS	220 to 250 DEG	95°	＜150°
PC	220 to 230 DEG	148°	＜210°
				SAN	200°	108°	＜165°

The invention provides, in particular in the case of PET, for the front side of the bristle carrier to be heated to a temperature in the range from 75 to 95 ℃, in particular from 80 to 90 ℃, and in the case of PP to be heated to a temperature in the range from 115 to 125 ℃, in particular from 110 to 120 ℃.

In particular, polypropylene PP having a Melt Flow Index (MFI) of 6 to 35, preferably 10 to 15, is used.

the method according to the invention in a preferred embodiment provides not only a bristle which is inserted in its entirety into a receiving opening, but also a plurality of fastening openings and a plurality of receiving openings in the bristle carrier or in the mold part. These receiving openings are aligned with the associated fastening openings, respectively. The bristle tufts are inserted into the receiving openings, which are then inserted into the fixing openings, preferably simultaneously. The mould parts simultaneously heat at least the edges of the fixing openings, preferably the entire contact surface, so that the entire area between the fixing openings is heated. By applying pressure on the front side of the bristle carrier, the fastening openings are simultaneously closed and the bristle tufts are thereby simultaneously fastened.

Preferably, the contact area between the mould part and the bristle carrier on the mould part and the front side of the bristle carrier facing the mould part are flat. There are also bristle carriers, however, which have a convexly or concavely curved front side. The mold sections have end faces complementary thereto.

The feed motion of the mold section relative to the bristle carriers can be controlled in pressure and time and/or in pressure and stroke.

As a further alternative, the device can be locked simply by, for example, providing a motor (for example, driven via a spindle), wherein the current and power consumption of the motor is detected and, from reaching a predetermined limit, the device is assumed to be in the closed position in which the holder and the mold part preferably touch each other. The hold time may then be counted from this moment.

The concept of "movement or feed movement of the mold sections relative to the bristle carriers" means: one or both of the two components move relative to each other.

Another variant of the invention provides for: the mold portion applies a pressure, which preferably remains constant, to the bristle carrier for a predetermined time from the moment of contact with the bristle carrier. This alternative method can be implemented particularly simply because a pressure is simply applied and over a period of time, so to speak as an action time, to the bristle carrier in order then to move the mold part and the bristle carrier away from one another again. No further method steps are required here for fixing the bristles or one or more bristle tufts in the bristle carrier, as in the other variants of the invention.

The feed motion of the mold portion relative to the bristle carriers and/or the pressure applied by the mold portion to the bristle carriers can occur non-linearly over time from the time the bristle carriers contact the mold portion until the maximum feed stroke is reached. Thus, for example, a longer or shorter initial action time of the temperature can be achieved, followed by the application of additional pressure in order to further and permanently deform the bristle carrier material.

In contrast to the prior art described above, the fastening end of the at least one bristle or of one or all bristle tufts, when inserted into the associated fastening opening(s), can of course be smaller than the cross section of the fastening opening before its deformation and before the bristle carrier is heated. This means that: the bristle tufts are not pressed into the side walls of the fixed openings as proposed in the prior art. The fastening end is also not pressed into the bottom of the fixing opening, because this bottom is not heated or not heated sufficiently to soften. Furthermore, no axial force is exerted on the bristles, which exceeds the force required to slide the bristles out of the receiving openings.

The longer action time of the mold part on the bristle carrier, during which pressure is applied to the bristle carrier and the bristle carrier is additionally heated, is important for the present method and is a great difference from the prior art. The action time is at least 4 seconds, in particular at least 5 seconds and at most 15 seconds, in particular at most 10 seconds. Over this extended period of action, the pressure can remain constant and/or continued heating of the bristle holder can occur. The fixing opening can be a blind hole, in particular with a depth of at most 4mm, in particular at most 2.7 mm.

The thickness of the bristle carrier is reduced by the method according to the invention, since the bristle carrier is deformed in the region of the front side.

The fastening opening is deformed and shrunk only up to a depth of at most 85%, in particular at most 70%, preferably even at most 60%, of its total depth, i.e. it does not shrink in the region of the blind hole bottom.

A further important difference from the prior art is also the applied pressure, which is much higher than in the methods proposed hitherto. I.e. the mould part exerts a pressure of at least 200bar, in particular at least 400bar, on the bristle carrier.

By means of the invention it is also possible to produce brushes with bristle tufts extending obliquely to the front side. This is surprising since the mouth edge of the fixed opening is located, as it were, locally below the obliquely running bristle tufts by the oblique orientation of the bristle tufts and is therefore, on the one hand, more difficult for the shaping die to reach and, on the other hand, the deformation of the material in this region should in fact lead to a correction of the obliquely running bristle tufts. However, as has been demonstrated in experiments, this is not the case. The method according to the invention and the device according to the invention thus also enable bristle tufts to be built obliquely in the bristle carrier.

In particular, a magazine is used as a mold part, which magazine is provided with the at least one bristle or the at least one bristle tuft. If it is desired to fasten a plurality of bristles or bristle tufts to the bristle carrier, all bristles or bristle tufts are arranged in the same magazine and inserted simultaneously after the assembly.

The fastening end of the bristles or bristle tufts protrudes from the magazine after the mounting with its fastening end and is heated at this fastening end without having to leave the magazine. A thickening is then formed on the fastening end projecting freely from the magazine. That is, the magazine is not a pure die, but rather a transport tool that is moved laterally away from the mounting station toward the bristle carriers and then pressed against the bristle carriers.

The thickened portion, i.e. the thickened fastening end, can be actively cooled immediately, i.e. directly after its production, before it is inserted into the fastening opening in the bristle carrier. Thereby enabling an increase in cycle time. In addition, the following situations are avoided: the thickening then deforms when pressure is applied so that the bristles are no longer optimally aligned with each other. The active cooling does not for example mean: the thickened fastening end is cooled in the device by the ambient temperature prevailing there. Rather, means for cooling, for example an active air flow generated by a blower, are provided. This air flow can either carry ambient air, for example from a location further away from the heated component, or can carry cooled air from the air conditioning system. A further possibility is to provide a cooling chamber through which the fastening end is conveyed with the bristle or bristles.

As already mentioned, the mold part has, for example, a flat end face facing the bristle carrier (at least in the contact region with the bristle carrier) and/or a geometry which cannot project into the fastening opening, that is to say without pin-like projections or the like, as is proposed in the prior art.

as has already proven, the position of the interface between the holder and the mould part, in which the two bear against one another, relative to the bristle carrier is important. It is therefore advantageous: the cavity for accommodating the bristle carrier is not only formed in the holder, but also partially in the mold part. However, based on the thickness of the bristle carrier, the major portion of the cavity is formed by the recess in the holder. The interface should preferably be located in the vicinity of or directly adjacent to the rounded transition between the side and front faces of the bristle carrier, that is to say outside the rounded transition. This rounded transition is therefore absolutely not provided with any projections or burrs produced by the pressed-out material of the bristle carrier.

The overall thickness of the bristle carrier is permanently reduced, that is to say not only partially but also overall, by the application of pressure and heat or by the application of pressure alone. In particular, the end face of the mold part opposite the bristle carrier is heated to a temperature of at most 140 ℃, in particular at most 130 ℃. For example, polypropylene, PET, ABS or SAN are used here as materials for the bristle carrier.

In the case of PET as bristle carrier material, it has been demonstrated that: the front side of the bristle carrier should be heated to 75 to 95 ℃, in particular 80 to 90 ℃, during deformation and to 105 to 125 ℃, in particular 110 to 120 ℃ in the case of PP (e.g. having a Melt Flow Index (MFI) of 6 to 35, preferably 10 to 15) being used.

As already mentioned briefly above, at least one previously raised elastomeric cleaning element can be injected onto the bristle carrier and fastened thereto by an elastomer, in particular a thermoplastic elastomer (TPE), before or after the fastening of the at least one bristle, wherein the cleaning element is arranged on the edge of the bristle carrier and/or inside the edge between the bristles or bristle tufts. It is thus possible to consider mixed shapes of cleaning elements in one and the same brush. The sprayed cleaning elements, the bristle tufts which are fastened to the bristle carrier by deformation of the edge of the fixed opening, and the individual bristles in the form of prefabricated elastomeric cleaning elements which are likewise fastened to the bristle carrier by deformation of the edge of the fixed opening can be mounted in any combination on the bristle carrier. Furthermore, the brush body can be constructed as a multicomponent injection molding.

The bristles can also be bristles which have been tapered beforehand, to be precise bristles which have been tapered beforehand chemically or mechanically, or bristles which have been rounded beforehand.

A plurality of bristle tufts can be held in the same bristle carrier, wherein at least one bristle tuft is composed of bristles of a different material having a different melting temperature than the bristles of at least one other bristle tuft. The bristle tufts made of different bristle materials are heated to different extents in order to melt the bristles of a bristle tuft together in order to form a thickened fastening end. This can be achieved in different ways: the distance between the end of the bristle tuft facing the heating device and the heating device is adjusted differently depending on the bristle material and/or the heating device is heated to different temperatures depending on the bristle material and/or different heating devices are used which are heated to different temperatures in a manner adapted to the bristle material used.

For example, to press the bristle tufts out of the magazine to different extents. Those bristle tufts which are composed of a more meltable material are closer to the magazine than other bristle tufts, for example, so that bristle tufts which are moved out to a greater extent are closer to the heating device than other bristle tufts and are therefore heated more strongly. Alternatively, the bristle tufts can also be processed one after the other in such a way that the bristle tufts with different bristle materials are moved out of the magazine one after the other with their fastening ends in order to then come closer to the heating device. Either the heating means are then heated to two suitable different temperatures or heating means of different heat are used for their respective arrangement of bristle tufts.

In the case of brushes with polyamide bristles and with PBT bristles, for example, the bristles made of polyamide are heated first and then the bristles made of PBT.

The advantageous variants described above can also be combined with one another in any desired manner.

The invention furthermore relates to an apparatus for carrying out the method according to any one of the preceding claims for producing a brush having at least one bristle or at least one bristle tuft, characterized in that: the device comprises a plurality of work stations, wherein there are an injection station for producing a bristle carrier and a subsequent fixing station for fastening the at least one bristle in the bristle carrier, wherein in the injection station there is an injection-molding half-mold having at least one pin which projects into an injection cavity and which forms a section of the injection-molding half-mold and which produces a fixing opening which is designed as a blind hole, wherein the pin projects from a base surface of the injection-molding half-mold and is designed with a chamfer on the transition of the base surface to the pin for forming a complementary chamfer in the region of a transition edge on the bristle carrier, and the device has a mold part which has at least one receiving opening for the at least one bristle or the at least one bristle tuft, wherein the receiving opening opens out on an end side of the mold part facing the bristle carrier, and the mold part has a heating device for warming at least a section of the end flank, which is designed and set to heat the end flank to a temperature of at most 140 ℃, in particular at most 130 ℃.

The term "injection-molding half-mold" is understood in the following as a one-piece part which completely forms the inner side of the cavity in the injection-molding mold half, or as a part or a group of parts of a multi-piece injection-molding mold half in which a plurality of parts together form the inner side of the cavity in the injection-molding mold half. In the latter case, in particular the bottom section of the cavity in the injection-molding half-mold is a separate part which is slidably inserted into an opening of a second part which in turn defines an edge of the pocket.

The plant according to the invention does not necessarily have to have workstations arranged in the same production plant or at the same production site. Rather, the individual workstations can of course also be located at different locations spatially separated from one another. The chamfer on the pin to the base surface produces the desired chamfer on the transition edge during injection molding, which then achieves the advantages during pressing of the bristle carrier and fixing of the bristle tufts.

The mould part exerts a pressure of at least 200bar, in particular at least 400bar, on the bristle carrier.

In order to form the aforementioned advantageous dimensioning of the chamfer on the transition edge, the complementary chamfer on the transition between pin and base surface on the injection-molded half-mould part has an axial length of at least 0.1mm and at most 0.5mm, in particular at most 0.35mm, and a radial width of at least 0.1mm and at most 0.35 mm.

Finally, the invention also relates to an injection-molded half-mold, which is used in the aforementioned injection station. The injection-molded half-mold has at least one pin which projects into the injection-molded cavity and forms a section of the injection-molded half-mold and which forms a fastening opening in the form of a blind hole, wherein the pin projects from the underside of the injection-molded half-mold and is formed at the transition from the underside to the pin with a chamfer for forming a complementary chamfer in the region of the transition edge on the bristle carrier. The chamfer on the transition between the pin and the base surface on the injection-molded half-mold has an axial length of at least 0.1mm, at most 0.5mm, in particular at most 0.35mm, and a radial width of at least 0.1mm to at most 0.35 mm.

the injection-molded half-parts can have an insert part made as a separate component, which projects into the opening of the remaining injection-molded half-part and projects with a free end against the front side and thus forms a pin. This can considerably simplify the production of the injection-molded half-mould as a whole, since no recesses have to be milled or eroded out of the base surface. Rather, holes need to be made and then inserts with pins are inserted into these holes.

The insert itself can also be configured as: it has a base which fits in said aperture and the free end portion constituting the pin has a reduced width with respect to the base. In this case, the chamfer is formed completely on the insert, since the seat forms the transition between the pin and the remaining bottom surface. The base may also define a portion of the bottom surface itself

In particular, polypropylene, PET, ABS or SAN are used as bristle carrier materials.

In the device according to the invention, the mould part which functions as a temporary carrier for the bristles or the one or more bristle tufts is used as a punch and simultaneously as a transport means. The heating means on the end side of the mould part are designed and adjusted via the control system such that said end side is heated to a temperature of at most 140 c, in particular at most 130 c, as it moves towards the bristle carrier. Although higher temperatures can theoretically be transported, devices whose control or regulating system limits the temperature accordingly in a predetermined manner also belong to the category of defined devices.

As already explained above in connection with the method, the feed movement of the mold part relative to the holders of the bristle carriers, which can be controlled in pressure and time and/or in pressure and stroke or only in time or only in stroke, can be achieved by a movement of the holders and/or the mold part.

The device according to the invention is capable of exerting a pressure of at least 200bar, in particular at least 400bar, on the bristle carrier, that is to say in the direction of the holder.

The heatable properties of the mold part should be designed over the entire contact area with the bristle carrier or even over the entire area of the end side of the mold part which is opposite the holder and thus the bristle carrier embedded therein.

As has also been explained in connection with the method according to the invention, the mold part is, for example, a magazine, which is provided with the at least one bristle or the at least one bristle tuft in an assembly station of the device. The at least one bristle or the at least one bristle tuft (in general, one or more bristle tufts also belong to the category "at least one bristle" for the present overall description and claims) protrudes with its fastening end from the magazine after the equipping. One or more of the fastening ends are heated in a melting station located after the equipping station, whereby a thickening is formed in each case. In the case of one or more bristle tufts, the bristles of the respective bristle tufts are united with one another by thermal deformation. In particular to form a mushroom-shaped, truncated spherical or spherical thickening.

In general, in the device according to the invention either the magazine can be moved and the work station is stationary, or the magazine remains stationary and the filling tool or the heating device or the holder is moved relative to the magazine. These tools or holders can be arranged, for example, on a rotating carousel which in turn carries away stationary (stationiert) magazines. The apparatus according to the present invention has a control system that controls the feed motion of the mold section relative to the bristle holders and the heating of the mold section so that the mold section is heated before it contacts the bristle holders. This means that: the mold part is already hot before the feed movement of the mold part in the direction of the holder. A maximum operating temperature may, but need not, be present at this stage. The bristle carrier is heated by the tool part only after the at least one bristle has been inserted, which is achieved by the thickened end section relative to the magazine and the excess section of the distance between the end face of the magazine and the corresponding contact surface on the bristle carrier.

The device according to the invention is in particular configured such that: so that the mold sections are continuously heated to the desired temperature necessary to heat the front side of the bristle carrier for the deformation process. This means that: when the at least one bristle or one or more bristle tufts are inserted into the one or more receiving openings, the mold part is also already hot and at this desired temperature. If the mould part also accommodates the at least one bristle/bristle tuft when the bristle ends are melted in order to form the thickened fastening end, care must be taken that: the temperature of the mold part and/or the residence time of the at least one bristle/bristle tuft in the receiving opening does not lead to a deformation of the bristles or bristles of the bristle tuft.

The control system can heat the mold part to a temperature and control the advance of the mold part relative to the bristle carrier in such a way that the mold part heats the brush carrier in the region of the contact surface with the mold part to a temperature during the advancing movement of the mold part toward the bristle carrier and/or upon contact with the bristle carrier, which temperature is below the melting temperature of the material of the bristle carrier and preferably is greater than or equal to the glass transition temperature of the material of the bristle carrier, in particular the control device being designed such that it is programmed, in the case of bristle carrier materials having a glass transition temperature of greater than or equal to 300 degrees kelvin, to adjust the temperature of the mold part to a maximum of 15% above the glass transition temperature, calculated in degrees kelvin, and, in the case of bristle carrier materials having a glass transition temperature of less than 300 degrees kelvin, to adjust to a maximum of above the glass transition temperature, calculated in degrees kelvin 50 percent.

Clearly, brush bodies or bristle carriers manufactured by standard single-component or multi-component injection molding methods can be transported in the method according to the invention or in the apparatus according to the invention. This makes it possible to use handles used in toothbrushes or more generally brush bodies or bristle carriers which are originally butt-jointed in a conventional manner using (metal) fastening techniques (bestopfen). However, typically these handles/brushes/bristle holders have a deeper mounting opening than is required in the method according to the present invention.

for some years, multi-component handles or brush bodies or bristle carriers have also been provided in the fastening technology, in which an elastomer structure is sprayed in the region of the head of the brush body between the fastening opening and/or the edge of the brush head. A tongue scraper, such as an elastomer, may also be mounted and sprayed on the back of the brush head. All these possibilities also apply to the method according to the invention and to the device according to the invention.

In the fastening technique, these elastomer structures are mounted on the front or back side before bristle mounting (beborstung) takes place. The elastomeric structure is only installed after the bristles are installed in exceptional cases, which is however not usual. In most cases, these elastomeric structures are injected onto a more rigid support structure in a multi-component injection molding mold. Such multi-component molds for toothbrush bodies are popular.

The handle, the brush/bristle carrier supplied in the method according to the invention and/or the device according to the invention can be injected without problems with all the brush injection molding techniques and molds known today. The fixing openings are pre-injected by means of mold pins, which can have a round or any cross-sectional shape and which project into the injection chamber. After the injected plastic has cooled and/or hardened sufficiently, the pins can then be pulled out of the cavities, for example by means of a pusher, before the injection-molded part is completely demolded. Here, the profile pins can be mounted parallel and/or at an angle to one another in order to thus create parallel and/or angled fixing openings in the injection-molded part. In the method according to the invention and the device according to the invention, the pin can typically enter the injection chamber slightly more shallowly in the case of injection of such a component than in the case of injection of a brush or bristle carrier which should be docked using the fastening technique (ankerechnik). The fixation opening is therefore slightly shallower in terms of injection length. Since these openings are not so deep, the total head thickness of a brush manufactured with the method according to the invention and the device according to the invention can be designed much smaller than in brush heads docked with a fastening technique. This results in a trimming advantage (ein klischer Vorteil) in the case of toothbrush manufacture.

The method according to the invention and the device according to the invention have particular advantages in the case of using a transparent, that is to say transparent, material for the bristle carrier or brush body. Such materials are typically PET, copolyester, SAN, ABS, etc. These materials may have a previously injected fastening opening and/or be provided with an elastomer (e.g. thermoplastic elastomer (TPE), thermoplastic polyurethane elastomer rubber (TPU)) by a multicomponent method, as in the case of bristle carriers/brushes/handles composed of polypropylene. After the bristle carriers/brushes/handles are then injected by the multicomponent method, they can be further processed as previously described and subsequently described with the aid of the apparatus, as specified for this purpose in the present invention.

In the course of the process for producing the brush, an injection station for producing the bristle tuft carrier can be provided in terms of time and/or space before a workstation having a holder and a mold part, which functions, for example, as a punch, in which injection station there is an injection-molding half-mold part having at least one pin which projects into an injection cavity and is immovably fastened on the injection-molding half-mold or on a part, possibly a one-piece part, of the injection-molding half-mold. Thus, the active pushers used hitherto in injection molding mold halves are partly or even completely superfluous. I.e. each pin creates a fixing opening configured as a blind hole. Pushers are not only expensive to manufacture, but also to maintain and repair. Since in the device according to the invention no fixture is used which requires a minimum depth for the fixing openings for fixing the bristles or bristle tufts in the bristle carrier, fixing openings with a smaller depth are entirely sufficient for fixing the bristles or bristle tufts. It is to be emphasized that: the injection station does not necessarily have to be spatially disposed next to the workstation with the holder. Rather, the injection station may be in other manufacturing plants locally or at a remote manufacturing site, such as in other cities, so that, for example, bristle carriers can be produced for storage and then shipped to other manufacturing plants or other manufacturing sites for deployment of bristle tufts.

In the described embodiment, the injection-molding mold halves can be formed by the first part and/or by an insert accommodated in this first part. The insert has pins that project from a front side of the insert. The insert is slidable relative to the first part, more precisely in a corresponding opening in the first part, which opening is closed by the insert.

The device according to the invention has at least one electric motor, preferably a servomotor, for exerting a pressure on the bristle carrier. The motor has the following advantages: the pressure can be adjusted very simply and the motor can be readjusted reliably and easily.

A plurality of motors for applying pressure may be provided. In addition, a motor may also apply pressure to multiple bristle carriers simultaneously by defining multiple cavities between a mold portion and a holder. In order to increase the throughput of the device, in particular a plurality of motors are provided, which respectively apply pressure to a plurality of bristle carriers.

In addition, the use of a rotary table or the like is advantageous in terms of improving the yield. For example, a plurality of units may be provided depending on which stations require longer cycle times.

The device according to the invention should have a control system programmed to: so that the mold sections are continuously heated in operation to the desired temperature when pressure is applied to the bristle carrier. There is therefore no temperature fluctuation expected during operation and therefore no heating time of the mould parts which has a negative effect on the cycle rate.

In addition to this, it is explicitly stated here that: the advantages and features mentioned above in connection with the method according to the invention can also be applied to the device according to the invention, to be precise the method according to the invention can be applied individually or in combination.

Furthermore, it is to be emphasized that: the method according to the invention and the device according to the invention can be applied in any brush, not just a toothbrush. For example, the method and apparatus may also be used for household brushes, floor brushes, household whisks or any type of whisk, car wash brushes, toilet brushes, hair brushes, cleaner brushes, hand brushes and any type of brush pen, for example for painting, drawing, or nail polish brushes, facial brushes (as well as toothbrushes, manual or electric brushes). The details and variants described in the subsequent figures can therefore also be used for all these brushes.

Drawings

Further features and advantages of the invention are obtained from the following description and from the following reference to the drawings.

In the drawings:

FIGS. 1a to 1g are a perspective top view and a perspective bottom view of different successive steps of the method according to the invention, which also show the apparatus according to the invention;

FIG. 2 is an enlarged perspective bottom view of the stationary station of FIG. 1 e;

FIG. 3 is a cross-sectional view of the mounting station shown in FIGS. 1e and 1f prior to movement of the magazine and bristle carriers toward one another;

FIG. 4 is a corresponding view of the station shown in FIG. 3 with the magazine and bristle carriers initially in contact;

Fig. 5 is a corresponding view of the fixed station shown in fig. 3 after the end of the feed movement and after the end of the action time, just before the work stations are separated and opened;

FIG. 6 is a cross-sectional view of an alternative set-up station;

Fig. 7 is a cross-sectional view of the holding station of fig. 3 in which obliquely oriented bristle tufts are being processed;

FIG. 8 is a cross-sectional view of a first embodiment of an injection molding die and an injection molding half mold according to the present invention for injection molding a bristle carrier for use in the method according to the present invention and in the apparatus according to the present invention;

fig. 8a is an enlarged detail view of the region marked with an X in fig. 8 according to a first variant;

Fig. 8b is an enlarged detail view of the region marked with an X in fig. 8 according to a second variant;

FIG. 9 is an elevational view of a bristle holder made in the present invention;

FIG. 10 is another injection molding mold and other injection molding half-mold parts according to the present invention for injection molding bristle carriers for use in the method according to the present invention and in the apparatus according to the present invention;

FIG. 11 is a cross-sectional view of the bristle carrier as the bristle tufts and/or individual elastomeric bristles are inserted;

FIG. 12 is a variation of individual preformed bristles for use in the present invention;

Fig. 13 shows a variant of the method according to the invention and of the device according to the invention;

FIG. 14 is a perspective view of a bristle carrier manufactured in an injection molded half mold according to the present invention for carrying out a method according to the present invention;

FIG. 15 is an enlarged cross-sectional view of the bristle carrier illustrated in FIG. 14;

Fig. 16 is an enlarged cross-sectional view of the bristle carrier of fig. 14 after the tuft of bristles has been inserted and before deformation, with the magazine not shown for simplicity;

FIG. 17 is a greatly enlarged detailed cross-sectional view of the bristle tufts and the surrounding bristle carrier after deformation, with the bristle carrier deformed to different extents shown as variations in the left and right halves of the drawing;

Fig. 18 is an enlarged perspective top view of a bristle carrier according to other variations made in an injection molded half mold according to the present invention.

Detailed Description

Fig. 1 shows an apparatus for manufacturing a brush, for example a toothbrush. Such toothbrushes are known to have a head with bristle tufts projecting at the front side, a neck and a handle. These three segments can be integrated with each other, which form a so-called brush body. The brush head can either be directly adjoined or it can be designed in two parts, with a lamella-shaped bristle carrier which, after injection molding, already has a pre-fabricated, blind-hole-shaped fastening opening, wherein the lamella-shaped bristle carrier is then placed together with the rest of the head, either by welding, gluing or injection molding. Further alternatives consist in: the brush head is designed as a whole so that it constitutes itself a bristle carrier.

Fig. 1 shows such an embodiment: the brush head also constitutes a bristle carrier. The bristle carrier 10 is simultaneously the brush body in this view, as it includes a handle, neck or brush head. The bristle carrier 10 is a pre-formed injection molded part. Fig. 2 shows: the bristle carrier 10 has a multiplicity of preformed openings 12, which are produced during injection molding, on the underside thereof, and in which the bristle tufts are inserted and fixed. However, the following description is equally applicable to the sheet-like bristle carrier 10 and will be clear.

the apparatus shown in fig. 1 comprises a plurality of work stations, namely a preparation station 14 shown in fig. 1a and 1b, a melting station 16 shown in fig. 1c, and a fixing station 18 for bristle tufts, which is shown in fig. 1e and 1 f.

The magazine 20, also referred to as a mold portion, which carries the bristle tufts through the various stations passes through all the stations.

Although fig. 1 shows a magazine 20 with receiving openings for brushes, which will be shown in more detail later, the magazine 20 is preferably dimensioned in practice such that a plurality of groups of receiving openings for a plurality of brushes are formed side by side in the magazine 20. It is also possible to have a plurality of rows of groups of receiving openings for a plurality of brushes.

The magazine 20 is, for example, a plate-shaped, constant-thickness part which has a flat upper end face 22 as shown in fig. 1. As a further alternative, the essentially plate-shaped magazine has, on its flat end face 22, a recess 200 with a base 202, which, as shown in fig. 14, can likewise be flat, in order to form part of a cavity for receiving the bristle carrier 10.

Since the magazine passes through a plurality of work stations and is then used for producing further brushes, there is a magazine circulation (Magazin-umlaufbetre) in the apparatus, in which a plurality of identically constructed magazines 20 pass through the various work stations in succession in a timed manner. The magazine 20 is thus a transport means for transporting bristle tufts 24 through the apparatus. As a further alternative, the magazine may be stationary and the various stations operate in a rhythm around the magazine, for example on a carousel. In this case, a plurality of fixed magazines, more precisely bristle tufts arranged in magazines, can be processed simultaneously.

The magazine 20 has a plurality of receiving openings 26 having a hole pattern that corresponds to the hole pattern of the bristle carrier 10.

each bristle tuft 24 comprises a plurality of bristles which are separated from a bristle reserve and inserted into the magazine 20 as shown in fig. 1a, for example via pins, as will be explained later. The individual bristle tufts 24 may be carried via a conduit with compressed air or vacuum.

the bristles consist of a thermoplastic material, in particular PA, PBT, polyester, copolyester or polypropylene, but they can also consist of an elastomer. Furthermore, coextruded bristles, for example having a core of PA with an elastomer coating, can also be used. As will be explained below with reference to fig. 11 and 12, it is not necessary either to use only the bristle tufts 24 and to insert them into the fastening openings, but rather only one individual, prefabricated bristle, for example in the form of an elastomeric cleaning element, can be inserted into the fastening openings and fastened in accordance with the method described above and below. Such cleaning elements are individually injected or foamed and are softer than the bristle carrier 10.

The bristle tufts 24 have opposite ends and project slightly from the magazine 20 with their back end 28, called the fastening end, i.e. their opposite end flanks 22 are slightly convex. This is shown in fig. 1 b.

as shown in fig. 1c, the magazine 20, which is completely equipped with bristle tufts 24, is conveyed laterally into the melting station 16. In this station, a heating device 30 is provided, which may be a plate heater or a hot air heater, for example. The back end 28 of the bristle tuft 24 is heated without contact so that the individual bristles exceed their melting temperature and a tuft merges into a thickened fastening end. The bristles of the bristle tufts 24 are thereby integrally connected to one another. The thickened portions 32 of the bristle tufts 24 do not blend into adjacent thickened portions of adjacent bristle tufts 24, but rather remain spherical or lens-shaped. It is also preferred that no punch presses against the still liquid material of the thickened portion or the melted bristle ends.

a plurality of bristle tufts 24 can be fixed in the same bristle carrier 10, wherein at least one bristle tuft 24 is composed of bristles composed of a material having a different melting temperature than the bristles of at least one other bristle tuft 24. The bristle tufts 24 made of different bristle materials are heated to different extents in order to melt the bristles of a respective tuft together in order to form a thickened fastening end. This can be achieved in different ways: the spacing between the end of the bristle tuft 24 facing the heating device 30 and the heating device 30 is adjusted differently depending on the bristle material and/or the heating device 30 is heated to different temperatures depending on the bristle material and/or different heating devices 30 are used, which are heated to different temperatures in accordance with the configured bristle material.

For example, to press the bristle tufts out of the magazine 20 to different extents depending on the bristle material. Those bristle tufts 24 which are composed of a more easily meltable material are held closer to the magazine 20 than other bristle tufts, for example, so that the bristle tufts 24 which continue to move out reach the heating device closer than the other bristle tufts and are therefore heated more strongly.

Alternatively, the bristle tufts 24 can also be processed one after the other in such a way that the bristle tufts 24 with different bristle materials are moved out of the magazine one after the other with their fastening ends in order to then reach the heating device 30 more closely. Either the heating means 30 are then heated to two suitable different temperatures or heating means 30 of different heat are used for their respective arrangement of bristle tufts.

The ejection of individual or groups of bristle tufts is achieved, for example, by means of a separate bottom plate 44 (see fig. 5), the constituent parts of which can be moved longitudinally along the bristles independently of one another.

The thickening 32 may optionally be actively cooled, either while in the melting station 16 or on the way to the subsequent stationary station 18 or in the stationary station 18. This is achieved, for example, by a cold air stream 214 (see fig. 1d) which is fed in via a blower or by the work station 1d being configured as a cooling chamber through which the magazine 20 is guided together with the still soft-backed thickening 32. The cycle time can be increased by cooling the thickened portion 32.

The magazine 20 continues to transport the bristle tufts 24 to the subsequent fixing station 18. The role of this fixed station is: the bristle tufts 24 are permanently locked in the fixed openings 12 of the bristle carrier 10 without fasteners only.

The fastening station 18 comprises at least one holding element 34 (preferably a plurality of holding elements 34) which, on its end side 36 (see fig. 2) opposite the end side 22, has a recess 38 (in the case of a plurality of bristle carriers 10 to be accommodated, a plurality of recesses) which is configured to complement the corresponding shape of the bristle carriers 10 in such a way that they rest with their rear side flat on the holding element 34 (see also fig. 14).

The retaining element 34 itself has a flat end face 36, to which the bristle carrier 10 is however slightly convex, as shown in fig. 2, in order to project into a recess 200 in the magazine 20, which recess is complementary to the region of the front side of the bristle carrier 10, as is shown, for example, in fig. 14.

The magazine 20 can be heated, for example, either by means of an externally introduced plate heater which is moved laterally in the fixing station 18 close to the magazine 20 and can heat it rapidly, since the magazine 20 is made of metal.

As a further alternative, a heating device, in particular a resistance heating device 39, which is shown in fig. 2 and 14, is formed in the magazine 20. Symbolically shown is a heating coil which is located near the end flank 22 or, in the case of a recess 200, near the bottom 202 of the recess 200, which bottom forms part of the end flank 22.

an electrical connection contact 41, for example a sliding contact on the lateral surface of the magazine 20, can electrically couple the magazine 20 when the magazine 20 enters the fixing station 18, in order to activate the heating device 39. Of course, also: the bottom 202 of the end flank 22, including the recess 200, itself constitutes a resistance heating layer, so that here the end flank is directly heated.

If the magazine 20 is stationary, the electrical connection of the heating device can be realized very simply, which can be designed to be continuous.

The heating device 39 functions to: preferably, the entire end side 22 that is in contact with the bristle holder 10 is heated, that is, the section between the thickenings 32 is also heated.

The end side 22 (in the region of contact with the bristle carrier 10) is heated to a temperature below the melting temperature of the bristle material and/or of the bristle carrier material, preferably of both materials. In particular it is at most 85% of the respective melting temperature of these materials, calculated in degrees celsius. If, for example, the two materials have a melting temperature of 100 ℃, the temperature of the finally heated magazine 20 on the end side 22 is at most 85 ℃.

Fig. 3 shows a cross-sectional view of the mounting station 18 of fig. 1e prior to relative movement of the magazine 20 and bristle carrier 10 together.

The thickened portion 32 has the following dimensions, viewed in the longitudinal direction a (also referred to as axial direction or feed direction): which is smaller than the corresponding cross section of the fixation opening 12 so that it can be inserted into the fixation opening 12 without colliding with or contacting the inner side 40 of the inner side edge of the fixation opening 12, also referred to as the inner side 40 of the wall defining the fixation opening.

In particular, the cylindrical fastening opening 12 has at this point in time only a maximum interference of 0.2mm, in particular a maximum interference of 0.15mm, with respect to the maximum cross section of the thickening 32 (fastening end). In other words, the lateral dimension of the thickened fastening end is smaller than the lateral dimension of the fixing opening 12 itself in the region of the bottom 208 of the fixing opening.

The underside of the thickened fastening end 32, with which the bristle tufts 24 are introduced into the fixing openings 11, is rounded or chamfered.

in that case the at least one fixation opening is injected as will be explained later. It has an inner side 40 with a draft, i.e. the inner side still extends slightly inwardly converging towards the bottom 208.

The magazine 20 and/or the holder 34, which are continuously moved together, i.e. heated to the desired temperature throughout the operation, are moved toward one another, in the present case only the holder 34 being moved together with the bristle carrier 10, so that the enlargement 32 first reaches the fastening opening 12 before the end flank 22 comes into contact with the flat end flank or front flank 42 of the bristle carrier 10 facing this end flank. During the feed motion, the bristle carrier 10 is hardly heated at all as long as the bristle carrier 10 is not in contact with the magazine 20, since the feed motion proceeds very quickly and there is no dwell time in the open position of the holding station 18 shown in fig. 3.

The base plate 44 (see fig. 3), on which all the bristle tufts 24 rest with their front, free end faces and which forms a support, can serve to align the bristle tufts 24 with one another at their front ends and at the same time to create a spacing between the thickenings 32 and the end faces 22, if desired. The base plate 44 serves as a support for the individual bristles and for the bristle tufts 24.

Fig. 4 shows: the end side 22 contacts the front side 42 of the bristle holder 10 and thereby heats the bristle holder 10 over the entire interface between the two portions.

The bristle carrier 10 consists of a thermoplastic material, in particular a plastic as already mentioned above, such as polypropylene, ABS, PA, PBT, PET or PC.

However, the movement of the retaining element 34 does not remain in the first contact position shown in fig. 4, because a high pressure is exerted on the bristle carrier 10 via the retaining element 34 and the magazine 20.

For example, a pressure of at least 200bar, preferably at least 400bar, is exerted on the bristle carrier 10 as it is relatively gathered. This pressure is already applied from the first contact of the bristle carrier 10 with the magazine 20 and remains the same over the action time (contact time).

this pressure is maintained for an action time of at least 4 seconds, particularly at least 5 seconds, and at most 15 seconds, particularly at most 10 seconds, while the bristle carrier 10 is heated.

The action time consists of the holding time and the period during the feed motion (referred to as the press-on time) which begins when the front side 42 is in contact with the magazine 20 and at the same time the back side of the bristle carrier 10 is in contact with the holder 34. The pressing time is ended when the maximum converging position is reached and the spacing of the holder from the mould parts remains constant during the holding time. The holding time is the time during which the feed motion is finished, that is to say the device is completely closed and the bristle carrier 10 is accommodated 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 pressing time, the spacing of the holder relative to the mold part is reduced extremely slowly and at a constant speed. For example, a total convergence distance of 0.3mm (Gesamtkompresisstreche) is passed in the fastest 3 seconds.

During the activation time, the heating of the magazine 20 is preferably continued, wherein the heavy magazine 20 in some cases allows the additional heating to be stopped after the first heating to the operating temperature. Nevertheless, heating of the bristle holder 10 continues during the action time.

In particular, the device is locked, i.e. the holder 34, outside the cavity formed by the recess 38 and the pocket 200, contacts a section of the end flank 22 outside the pocket 200 with the end flank 36 (see fig. 14). In this contact region, no gaps are provided into which material can enter from the cavity, that is to say the cavity is sealed by the annularly encircling contact region.

In general, it is also preferred, without being limited to the embodiment shown, that there is no heating device in the contact area between the holder 34 and the magazine 20, so that the heating device is only present and acts in the contact area between the front side 42 and the magazine 20.

The interface between the retaining element 34 and the mold part (here the magazine 20) which is delimited by the end flanks 36 is preferably closer to the front flank 42 of the bristle carrier 10 than to its back flank. Specifically, the interface is adjacent to or directly adjacent to a rounded transition between the side surfaces 212 that connect the front side 42 and the back side.

The beneficial results are: the support in the form of a bottom plate 44 is removed and no longer in contact with the bristles at least during the final phase of the application of pressure, i.e. at the end of the action time. This improves the accuracy of alignment of the bristles with respect to each other as well as with respect to the bristle carrier 10. Preferably, however, the base plate 44 is already removed before the start of the holding time and even before the action time, as this is symbolically illustrated in fig. 3 to 5 by the arrow Y. For example, the base plate 44 is used only in the workstation c) and if necessary d) shown in fig. 1.

However, in order to be able to fix the axial position of the bristle tufts and of the individual bristles over the entire action time, the cross section of the receiving opening 26 is matched to the cross section of the bristle tuft 24 inserted therein in such a way that the bristle tuft 24 is clamped in the receiving opening 26 and is thus reliably positioned axially. The bristle tufts 24 do not slip by their own weight or by inertia within the workstation and during movement from workstation to workstation.

In the illustrated example, the entire flat end face is heated, at least on the front face 42 of the bristle carrier 10, where it contacts the magazine 20. If the magazine 20 has a recess 200, it is beneficial and sufficient that: the heating means are only mounted in the area of the bottom 202 of the recess 200. However, since the magazine 20 is generally made of steel, the entire magazine 20 is heated. The temperature to be regulated, however, relates to: the front side 42 of the bristle holder 10 is heated to a desired temperature.

The temperature to which the bristle carrier is heated in the region of the front side 42 during the action time is below the melting temperature of the bristle material and/or the bristle carrier material, in particular 85% or below 85% of the respective melting temperature, calculated in ° c. This temperature thus corresponds to the aforementioned maximum operating temperature of the magazine 20 in the region of the end face 22 or the base 202.

As a further alternative, at least the edge 50 of the fixing opening 12 in the region of the front side 42, which edge constitutes the wall region of the fixing opening 12 adjoining the mouth opening into the front side 42, is heated.

The temperature at which the bristle carrier 10 is heated, at least in the region of the edge 50, and preferably throughout the entire contact area with the magazine, should not only be below or significantly below the melting temperature of the material, but rather within the glass transition temperature of the bristle carrier material. The bristle carrier 10 can only be heated in the region of the front side 42, at least in the region of the edge 50, to a temperature above a limit temperature, which in the case of bristle carrier materials having a glass transition temperature of 300 degrees kelvin or more is 60% of the glass transition temperature of the bristle carrier material, in particular 80% of the glass transition temperature of the bristle carrier material, with very high pressure, for example above 600 bar. However, it is preferred that this limiting temperature is at or minimally above the glass transition temperature. In the case of bristle carrier materials having a glass transition temperature of less than 300 degrees Kelvin, the heating temperature is a maximum of 50% above the glass transition temperature, calculated in degrees Kelvin.

Further variants provide for: in particular, at least the edge 50 of the front side 42, in particular the entire contact surface of the bristle carrier 10 in the region of the front side 42, is heated to a temperature of at least 30 ℃ above ambient temperature before the inner side 40 inside the fastening opening 12 is heated to above ambient temperature by the magazine 20.

As can be seen in the figures, the magazine 20 has absolutely no projections or the like, with which it projects into the fastening opening 12, since it has a flat end face 22 or a flat base 202 in the region of the front face 42.

Since the front side 42 is also flat and has no flanges or the like in the region of the mouth of the fixing opening 12, that is to say in the region of the edge 50, as is the case in the prior art, the bristle carrier material deforms optionally even over the entire area in the region of the front side 42 when pressure and temperature are applied. The material is to be displaced and thereby moved into the fixing opening 12 in the mouth region and the fixing opening is shrunk.

By applying heat and pressure, the overall thickness D and thus the maximum thickness of the bristle carrier 10 in the region of the mouth of the fastening opening 12 to the front side 42 is permanently reduced. A bulge or constriction results which clamps the thickened fastening end from behind in the pull-out direction and thus fixes the bristle tuft 24.

No adhesion occurs between the thickened fastening end and the wall of the fixing opening 12.

The deformation of the edge need not be extreme. It has been demonstrated that: for example, in the case of a toothbrush the following are sufficient: the cross section of the fastening opening 12 with the original width or original diameter D3 is reduced in the region of the edge 218 (see fig. 5A) only to such an extent to a width or an inner diameter D1 that the difference between the diameter D2 of the thickest region of the thickening 32 (for the respective cross section) and the width or diameter D1 in the region of the edge 218 is only approximately 0.1 to 0.5 mm.

The beneficial results are: the upset 32 has an insufficient size when inserted relative to the fixation opening 12 that has not yet been deformed (i.e., D2 is less than D3).

From this viewpoint of inserting the thickened portion 32 in a not yet completely solidified state into the fixing opening 12, it is also possible that: overall, a thickening 32 is used, which is designed with an interference with respect to the cross section of the fastening opening 12, i.e., D2 is equal to or greater than D3.

The space formed by the fastening opening 12 and closed off to the outside by the narrowed edge 218 for the seating of the thickening 32 is shown exaggerated in fig. 5A, as well as the ratio of the thickening 32 to the diameter D1.

however, the fact is that: the entire wall forming the fastening opening 12 does not rest against the thickening 32 or against the outer bristles, which project from the thickening 32. Rather, the wall is deformed only in the region of the edge 218 and in the directly adjoining sections 220 which widen outward in the direction of the base 208 and only in these regions rest against the bristles or thickenings 32 and exert a pressure thereon.

However, in order to accurately fix the axial position of the bristle tufts, the thickened portion should contact the bottom portion 208.

In the remaining region, for example between the base 208 and the thickening 32 or in the region of the wall periphery adjoining the base 208, there are one or more recesses 222 between the wall and the outer side of the thickening 32, so that this thickening is not compressed, jammed and/or deformed in this region.

In the region of the edge 218, at least 3%, in particular at least 5%, of the compression of the bristle tufts 24 relative to their state in the magazine 20 is achieved by the narrowing and shrinking of the edge 218. In this case, 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 of the fastening openings 12 and thus all of the bristle tufts 24 are simultaneously fastened in the bristle carrier 10 by the illustrated device and the corresponding method.

As can also be seen in fig. 5 and 5A, the entire fixing opening is not deformed, but only up to a depth T which corresponds at most to 85%, in particular 70%, of the total depth T of the fixing opening 12 and/or which has an axial extent of 0.5 to 1.3mm, in particular 0.6 to 1.0 mm. The depth t is measured from the front side 42. If the front side 42 is flat, a plane located on the front side 42 is used as a reference plane. If the front flank 42 is concavely or convexly curved, an envelope of the front flank 42 is formed, from which envelope the depth t is measured.

the thickened portion 32 itself is preferably clamped in the fixing opening only in the axial direction over a maximum of more than 50% of its axial overall length. The remaining clamping takes place in the region of the bristles projecting from the thickened portion 32.

The walls of the fixing opening 12 are not deformed over a depth Z (see fig. 5A) of at least 0.8mm from the bottom 208 and/or do not grip the thickening 32 and the bristles in this region.

The depth T of the fixing opening after the manufacture of the brush is at most 4mm, in particular at most 2.7 mm.

All of the fixed openings 12 are blind holes and thus do not have to be covered on the back side of the bristle carrier 10, since the bristle tuft sections are not visible or do not protrude on this side.

The resulting attachment is the only attachment for the bristle carrier, and no metal anchor (Metallanker) or wire is required.

In general, it is emphasized that: this does not relate only to the illustrated embodiment, i.e., the bristle carrier 10 should not be brought close to its melting temperature, but rather significantly away from the melting temperature and close to the glass transition temperature. In particular, the heating temperature and thus the temperature of the magazine 20 in the region of the end faces 22 and the temperature of the bristle carrier 10 at the end faces should not be higher than 15% above the glass transition temperature of the bristle carrier material and/or the bristle material.

In the case of PET, the front side 42 is heated to a temperature of 75 to 95 ℃, in particular 80 to 90 ℃, in the case of PP, and 105 to 125 ℃, in particular 110 to 120 ℃, in a preferred variant of the invention during the deformation. The PP is particularly chosen to be: it possesses a Melt Flow Index (MFI) in the raw state of 6 to 35, preferably 10 to 15.

One embodiment of the invention provides for: the end side 22, and thus the bristle carrier 10, is heated to a temperature of at most 140 c, particularly at most 130 c, preferably to within the range of 100 to 115 c. Polypropylene, PET, ABS, copolyester and SAN are used as materials in this case, in particular for bristle carriers.

The back side 206 of the bristle holder 10 and the region from this back side 206 up to at least the bottom 208 of the fastening opening 12 (preferably still even further in the direction of the front side 42) should not deform. In order to have the temperature boundary from which deformation occurs due to 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 device.

This cooling is symbolically shown in fig. 3 by cooling channels 210 through which a cooling liquid flows. The cooling channel 210 is connected to a cooling water circulation circuit which pumps cold water, preferably below 20 deg.c, in particular even below 10 deg.c, through the holder 34. The back side 206 is thus maximally 25 c during the application of pressure. The side surfaces of the bristle carrier 10 that connect the front side 42 and the back side 206 can also be cooled sufficiently in the holder 34 so as not to deform and remain below the respective temperatures from which Deformation (Verformung) and Deformation (Deformation) can occur.

After a predetermined activation time, the holding element 34 and the magazine 20 are separated again, so that the bristle tufts 24 are pulled out of their receiving openings 26. No further processing in the form of other shapes for the bristle carrier 10 is required.

However, it is preferred not to carry out the separation at once, but rather to provide a standstill phase during the separation. To this end, the mold sections, i.e. the magazine 20 and the holder 34, are moved away from one another to a minimum, so that a small ventilation gap 228 (see fig. 5A) of 0.5mm or more is produced between the front side 42 and the mold sections, i.e. the upper side of the magazine 20. When this predefined ventilation gap 228 is reached at its height, the distance preferably remains constant for a rest period of at least 1 second, in particular at least 1.5 seconds.

Optionally, cooling air may also be blown through the ventilation gap 228 toward the front side of the bristle carrier 10 during this resting phase in order to cool the front side.

However, during this resting phase the bristles stay in the receiving openings 26, as shown in fig. 5A. The deformation region of the fixing opening is stabilized in the resting phase, so that a tuft of bristles extends parallel to one another and uniformly directed.

After the resting stage, the device is separated so that the completed bristle holder can be removed.

In order to control the respective movement and temperature precisely, the device has a control system 51 via which not only the heating temperature but also the pressure applied and the movement process are controlled. The heating device 30 can also be operated via the same control system 51.

If the bristle carrier material is a material such as certain polypropylenes (polypropylenarts) in which the glass transition temperature is not above ambient temperature, then heating of the bristle carrier can be omitted, although this is not necessarily so. It can also be advantageous here to heat the melt to a slight extent, however, also significantly below the melting temperature, still minimally above the glass transition temperature. If no heating or no heating is necessary in the case of such bristle carrier materials, the fixing opening 12 is closed only by applying the aforementioned pressure over the aforementioned action time. In this case, a magazine 20 without a heating device or an identical magazine with a heating device can be used, the heating device not being activated at all.

Independently of the bristle carrier material, the following apply: in the feed movement of the magazine 20 relative to the holder 34 and thus relative to the bristle carrier 10 (relative movement of the parts means that one or both of these parts can be moved in the direction of the other part), a pressure-and time-controlled feed movement and/or a pressure-and stroke-controlled feed movement can be advantageous.

Particularly advantageous are: in a first phase of the feed movement, the edge 50 or the entire front side 42 is heated to a temperature above a threshold temperature. If the bristle carrier material possesses a glass transition temperature above 300 degrees Kelvin, this limit temperature is 60%, in particular 80%, below the glass transition temperature of the bristle carrier material, measured in degrees Celsius. However, the limiting temperature is preferably the glass transition temperature, if appropriate up to 20% above the glass transition temperature (in ℃ C.). Then in a subsequent second stage of the feed motion, the edge 50 is deformed and the edge 50 is pressed towards the bristles.

As a further alternative, the feed movement takes place at a constant, low speed and the magazine 20 and the holder 34 are locked against one another when the bristle carriers are contacted on the front side and on the rear side and are thereby compressed axially.

In the embodiment shown in fig. 5, the material in the region of the edge 50 is also pressed against the bristles in the closed state, so that there is no gap between the bristles and the edge 50.

The setting of the magazine 20 can take place either directly via a bristle separator (borstevereinzelner) as in fig. 1a or via other variants shown in fig. 6. Here, a cartridge (Kassette)60 with a large number of receiving openings is first filled with bristle tufts. The separated bristle tufts can then also be stored via this magazine until they are finally pressed directly into the magazine 20, for example via the movable pin 62.

Alternatively, a diverter plate 64 can also be provided between the magazine 60 and the magazine 20, which diverter plate has oblique transport openings 66 for the bristle tufts 24 moving therethrough. It is also possible to: if, for example, the brush is to contain bristle tufts of different thicknesses, a plurality of bristle tufts 24 can also be combined into one larger bristle tuft as shown on the left in fig. 6 via the converging transport opening 66. Furthermore, the magazine can of course also have an obliquely extending receiving opening 26, since brushes are provided in which the bristle tufts do not extend perpendicularly to the front flank 42 and thus cylindrically, but are arranged obliquely to the front flank. However, the fastening is also shown here as in the figure. Alternatively, the fixed openings 12 can of course also be slightly inclined or tapered for such obliquely oriented bristle tufts 24 or, as shown in fig. 7, only tapered in the region of the side of the bristle tufts 24 that is inclined toward the fixed openings. This means that: the receiving opening 26 may have edge sections with different degrees of inclination.

In the embodiment shown in fig. 7, an edge section 80 of the fastening opening 12 extending obliquely, in particular parallel to the oblique receiving opening 26, and an edge section 81 opposite the edge section are provided. In the illustrated embodiment, the edge section 81 extends perpendicularly to the front side of the bristle carrier 10. Alternatively, however, the edge section 81 can also run at an angle, as the case may be, which is different from the angle of the edge section 80, as this is illustrated with dashed lines.

In the injection station belonging to the apparatus according to the invention, the bristle carrier 10 is manufactured in an injection-molding mold having injection-molding mold halves 100 and 102 as in its two variants shown in fig. 8 and 10. This injection station is positioned in front of the aforementioned station for docking the bristle carriers 10, either temporally and/or spatially as has been described previously. The injection station constitutes a bristle carrier injection apparatus. The injection mold halves 100 and 102 define a cavity 104 therebetween into which liquid plastic is injected to produce the bristle carrier 10. In the injection stations used hitherto, the injection mold half 100 is provided with pin-like, active pushers which project through the injection mold half 100 into the cavity 104 and are pulled out before the injection mold opens, while this variant provides a much simpler solution. In this case, one or more integrally formed pins 106 of arbitrary cross section are mounted immovably on the injection-molding mold half 100, said pins extending freely into the cavity 104. These pins 106 then create the fixed openings 12. The depth of these fixing openings 12 is much smaller than in the bristle carriers manufactured to date which are plugged with the fixing technique (Ankertech).

On the pin 106 on the right in fig. 10 can be seen: such a pin can be used for the purpose of producing an opening 12 which extends obliquely as shown in fig. 7 and 8.

In the case of an integral injection-molding mold half (see fig. 10), in which one part defines the entire inner side of the cavity, this injection-molding mold half is referred to as an injection-molding half-mold.

With 8), on which said projections have pins 106, for example integrally mounted on the insert. The insert 107 preferably has all the pins 106 required for the production of the fixing opening 12. After injection, the insert 107 is drawn down into the cavity in the injection mold half for easier demolding, thereby pulling the pin out of the injected fastening opening 12, thereby simplifying subsequent ejection or removal of the bristle carrier 10.

The injection-molding half-mold 100 in this case comprises a first injection-molding half-mold 101 which defines the entire lower half-mold 100 except for the region of the inlay. Furthermore, the injection-moulding half-mould 100 comprises an insert 107 which is received in an opening in the first portion 101 complementary to the insert 107, the insert constituting a second injection-moulding half-mould part. The insert 107 is movably supported relative to the first part 101 of the injection-molding half-mold 100 in a direction towards and away from the bristle tuft carrier. Preferably, no gap is provided between the first part 101 and the insert 107 into which liquid plastic can enter.

in fig. 10, on the right-hand projection 106 can be seen: the protrusion may be used to make an obliquely extending opening 12 as shown in fig. 7. The pin 106 can have at least one edge section which extends obliquely to the direction of movement of the insert 107 (see double arrow in fig. 10).

The insert 107 preferably defines the entire area of the front side of the head. With this insert 107, brushes can be produced without any outlay, which have the same bristle carrier 10, but different aperture patterns and different patterns of bristle tufts.

In the variant shown in fig. 8a, all the pins 106 are integrally formed on the insert 107 defining the injection-molded half-mould. In the variant shown in fig. 8b, the injection-molding half-part is designed in multiple parts, since it comprises a base part 300 with a plurality of openings 302 and an insert part 304 inserted into said openings 302. The inserts 304 have bases 306 with which they close corresponding openings in the base 300. Corresponding pins 106 extend from the base 306. This variant is simpler in terms of manufacturing process.

Important in making the bristle carrier 10 are: where necessary, a so-called transition edge 320 (see fig. 14) between the front side 42 and the inner side 40 of the fastening opening 12 is chamfered.

As can be seen in fig. 14, not all transition edges 320 need to have such a chamfer 322.

The chamfer 322 is shown partially enlarged in the cross-sectional view of fig. 15. In the enlarged view, the area K shown in hatched lines symbolically shows the material which the transition edge 320 no longer has as a result of the chamfer 322. As reference lines, a continuation of the front flank 42, also referred to as the envelope 322, and a line 324 are provided here, which represents a straight continuation of the inner flank 40 up to the envelope.

The chamfer 322 may have a different cross section from the fixation opening 12 to the fixation opening 12, which is shown, for example, in the enlarged view of fig. 15. As an alternative to the solution shown in fig. 18, the chamfer 322 may have a different cross section along the periphery of the transition edge 320. In this case, for example, in fig. 18, the section 330 is beveled more steeply than the section 332 of the same bevel 322.

The chamfer 322 can extend along the entire circumference of the transition edge or over only a partial region. As can be seen, for example, by means of the fastening opening 12' in fig. 15: the transition edge 320 has a chamfer 322 on the left side and no chamfer on the right side, so that in this region the inner side 40 extends at right angles to the front side 42 and intersects the latter to form a sharp transition edge.

If different cross sections are present in the chamfer 322 along the circumference of the transition edge 320, these cross sections can start in the same axial depth of the fastening opening 12, measured from the front flank 42 adjoining the chamfer 322 or from a section of the front flank 42 adjoining the chamfer.

The chamfer 322 can be formed by a rounded corner, in particular a radius or a chamfer, as shown in the two central enlarged views in fig. 15.

The chamfer 322 is present only at the mouth of the fastening opening 12, i.e. in the region of the transition edge 320 and hardly extends into the fastening opening 12. The chamfer 322 extends, measured from the front side 42 adjoining the chamfer 322, into the fastening opening 12 by at most 0.5mm, in particular by at most 0.35mm and by at least 0.1 mm.

the radial width of the chamfer 322 is in particular at least 0.1mm and at most 0.5mm, in particular at most 0.35 mm.

As can be seen from fig. 15, but also from fig. 14, even in the case of a very thin web 340 between adjacent fastening openings, this web 340 extends as far as the front face 42 of the bristle carrier 10 and forms a section of this front face. This means that: said webs extend as far as the envelope of the front side 42 (if the front side is shaped convex or concave) or, if this front side 42 is flat, as far as the plane of the front side 42 without protruding from this plane.

Since the fastening opening 12 and the front side 42 are all formed by injection molding, just like the chamfer 322, the configured injection molding half-module has a chamfer 342 on the transition between the pin 106 and the bottom side (end side) of the injection molding half-module, which is complementary to the configured chamfer 322. The above-mentioned preferred dimensions of the chamfer 322 also correspond to the corresponding dimensions of the chamfer 342.

In the embodiment shown in fig. 8b, the bottom (end side) is also formed in part by an insert, more precisely an insert in the base 306. The chamfer 342 is thus formed entirely in the insert 304.

When the bristle tufts 24, 24' are inserted into the associated fastening openings, the thickened fastening end does not contact the chamfer 322, since the receiving opening in the magazine 20 is for this purpose perfectly aligned with the fastening opening 12.

Upon deformation, the chamfer 322 constitutes an additional buffer space or receiving space for the material which is pressed in and shrinks the fastening opening 12 at its mouth.

In fig. 16 can be seen: the bristle tufts 24 are embedded perpendicular to the front face 42 or, like the bristle tufts 24', obliquely to the front face. In the case of inclined bristle tufts 24 ', the chamfer 322 is formed larger on the side of the transition edge which is closer to the bristle tuft 24' than on the remaining circumference of the transition edge. In the present case, there is no chamfer even on the side (right side) remote from the bristle tufts 24 and there is a chamfer 322 on the transition edge 320 in the rest of the periphery.

The fixed bristle tufts 24 can be seen in detail in fig. 17.

The corresponding magazine 20 has deformed the material of the bristle carrier 10 in the region of the front side 42 in fig. 17, thus reducing the overall thickness of the bristle carrier 10.

The material partially closes the fastening openings 12 like a bottle neck and can here be pressed against the outer bristle tufts 24 (see left half of fig. 17) or still be slightly removed from the outer bristle tufts (see right half of fig. 17). The inwardly displaced material does not, however, enter the gap 350 between the receiving opening in the magazine 20 and the outer side of the bristle tufts 24. Whereby no material is displaced from the fixation opening 12 to protrude from the front side 42.

As can be seen in fig. 14, preferably none of the fastening openings 12 has a projection which is convex with respect to the front side before deformation. This means that: all material closing the fixed opening 12 must be provided by reducing the thickness between the back side 206 and the front side 42 of the bristle holder 10.

Fig. 9 shows a different variant, as the bristle carrier 10 can be designed. Not only can a circular or oval fixing opening 12 be provided, but also any desired shape can be formed. For example, elongated openings, X-shaped, C-shaped or any differently shaped fastening openings can be realized. The large fixed openings are provided with bristle tufts which consist of a plurality of separate bristle tufts which are connected to form one large bristle tuft by melting their ends. Such large bristle tufts produce a corresponding wall-shaped bristle structure.

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

Overall, the fastening openings 12 therefore do not necessarily have to be used exclusively for receiving and fastening the bristle tufts, but rather the individual bristles of any type, which are prefabricated and made of any elastomer plastic, can be received and fastened exactly as described above in connection with the bristle tufts. The bristles can have a plate-like shape and can be inserted into an elongated fastening opening 12, for example, and can be inserted therein by deforming the edges of the fastening opening 12. For example, pre-injected cleaning elements with a C-shaped cross section are inserted as individual bristles into the C-shaped fastening openings 12. Furthermore, bristle tufts 24 comprising a plurality of bristles 24' can of course also be embedded in the bristle carrier 10. The individual bristles 24' can also be positioned, for example, in the middle in the region of the bristle tufts 24 or, conversely, enclose individual bristle tufts 24 or a plurality of bristle tufts 24.

It is to be emphasized that: the features described above with the aid of bristle tufts can also be used for individual large bristles. Merely by way of example, a plate-shaped bristle which extends obliquely to the bristle carrier 10 is illustrated, which bristle is inserted into the oblique fastening opening 12 in fig. 7 and fastened therein. However, the individual bristles can also have a fastening end 32 from which the elongate rest projects in a bent manner, so that they can be inserted into the cylindrical fastening opening 12 shown in fig. 4, but the bristles extend obliquely beyond the fastening opening 12.

The individual, separately manufactured bristle 24 'or bristles 24' are preferably fixed in the bristle carrier 10 simultaneously with the bristle tufts 24 by deforming the corresponding edges of the fixed openings 12. As a further alternative, it is possible: a plurality of separate, successive shaping processes are carried out for the different bristles or bristle tufts. In this case, since the bristles or bristle tufts are composed of different materials, different pressures and/or temperatures can also be applied, if appropriate, by one or more heated mold parts.

In addition to or as an alternative to the above-described variations, the elastomeric cleaning elements 108 may, for example, be sprayed on the edges of the bristle carrier 10. These cleaning elements 108 are not pre-fabricated, however, they are also raised at the front relative to the bristle holder 10 and serve to massage the gums.

The bristle carrier 10 can have openings or recesses only on the edge into which the cleaning elements 108 are inserted, for example, on the edge. In addition, as is increasingly popular in the case of brushes, the back side of the bristle carrier 10 can also be injection molded with a softer plastic.

In the latter case, it is appropriate to: the cleaning elements 108 are gradually integrated into the back layer made of the softer plastic. As shown by the upper mold half in fig. 9 (which shows a variant with respect to the lower mold half), this back layer of softer plastic can also form a frame of harder plastic around the bristle carrier 10, in order to function as a buffer, for example.

Further variants consist in: the bristle carrier 10, here the head of the toothbrush, is connected to the neck of the brush body by a hinge 110 made of a softer plastic material.

In general, all variants are applicable: the bristle carrier may be a thin plate as part of the later brush body or the entire brush body. For example, the bristle carrier can also be a multicomponent injection molded part which already forms the finished brush body when the bristles are finally inserted. However, the reverse is also possible: bristles have already been embedded in a part of the brush body which then constitutes the bristle carrier, and this bristle carrier with the bristles mounted thereon is then subsequently encapsulated by injection.

The injection station can therefore also be designed as a multicomponent injection station, or a plurality of injection stations can be provided, between which the work station in which the bristles are fixed is located.

The cleaning elements 108 and/or individual bristles of elastomer material, prefabricated and optionally shaped in cross section, preferably extend at least as far forward as the bristle tufts, but they can also project beyond these bristle tufts or be shorter than these bristle tufts.

Fig. 11 shows: not only can the bristle tufts 24 be inserted with their thickening 32 at the fastening end into the fastening openings 12 and fastened therein by edge deformation, as already explained above, but also the individual, prefabricated bristles 24' (of any shape, viewed in side view or in cross-sectional view) can be embedded in the bristle carrier by the above-described method and the above-described device without fasteners. The bristles 24' are injected from an elastomeric material, particularly a thermoplastic elastomer (TPE).

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

Furthermore, the prefabricated bristles 24 ' may or should have thickened fastening ends 32 ' whose height is smaller than the depth of the associated fastening openings 12, so that the inwardly deformed edges enclose the fastening ends 32 ' for a form-fitting fastening. The fastening end 32' is, for example, a flat cylinder whose shape matches the shape of the fixing opening 12. However, the outer dimensions of the respective fastening end 32 'are adapted to the cross-section of the fastening opening 12, so that before the deformation there is a lateral clearance between the fastening end 32' and the wall of the fastening opening 12 during the insertion.

The fastening end 32 'may be constructed of a different material, particularly a harder material, than the rest of the bristles 24'. An example for this is a fastening end 32' consisting of polypropylene. It is also possible for only the core of the bristles 24' to consist of the harder material, which is then subsequently encapsulated by injection with the softer material. This allows for a disc of a harder material which constitutes the entire fastening end 32' or the core of the fastening end.

The disk 112 forming the core, according to the left-hand side of fig. 12, can likewise have integrally formed thereon a projection 114 which projects into the portion of the bristles 24' which is located outside the bristle carrier 10.

The variant of the bristle 24 'shown on the right in fig. 12 is constructed with a fastening end 32' made of hard plastic and a section 118 onto which softer plastic is sprayed.

the individual bristles 24' shown in fig. 12 are extending in a pointed angle, but this should not be considered limiting.

Fig. 13 shows a complete plant with different workstations. It is to be emphasized that: the apparatus according to the invention does not necessarily have all the workstations set forth below.

All variants and details which have been described with reference to the above figures, in particular with reference to fig. 1, can in particular also be realized in this embodiment, individually or in combination, whether it is, for example, cooling, ventilation, etc., and whether the aforementioned temperatures, temperature ranges or times and the materials used are irrelevant.

The bristles or bristle tufts are separated in the station a and transported further. The left image shows a so-called fiber box 120 from which the finished bristles (which may be sharpened mechanically or chemically) are removed in tufts by a bristle tuft separator 122.

These bristle tufts 24 are transported by the transport device to a workstation B, in which the bristle tufts 24 are already transferred, if necessary, into the final bristle tuft geometry (B ü schelgeymetrie) and into the hole pattern of the later brushes.

For example, the bristle tufts 24 are inserted into a first intermediate magazine (Zwischenmagazin)124, in particular in the form of a plate. The bristle tufts 24 are then moved, if necessary, by means of the ram 126 via the intermediate magazine 124 into a further plate 128, in which there are optionally deformation or deflection openings 130 or openings 132 for grouping a plurality of bristle tufts 24 into a larger common bristle tuft or for obliquely orienting the bristle tufts 24.

The bristle tufts 24 are then moved further into the magazine 20. The hole geometry of the later brush is then preferably realized in the magazine 20, but this is not necessarily so, as will be explained further below.

However, if desired, the sheet material 128 and/or the intermediate magazine 124 can be omitted, so that the bristle tufts 24 are conveyed directly into the magazine 20. All this depends on the desired final tuft location or tuft geometry and the hole pattern of the finished brush.

In the work station B, the bristle tufts 24 can be conveyed mechanically, via a pusher or a pusher 126 shown in fig. 2, into the first intermediate magazine 124 and/or into the magazine 20 after separation. In workstation a, as a further alternative, in the second image on the left side: the separated bristle tufts are conveyed into the intermediate magazine 124 or into the magazine 20 via a tube or hose 134, in which an overpressure or underpressure is applied.

it is irrelevant what transport means are used for the bristle tufts, which can be transported and/or inserted individually in succession, in groups in succession or all at once into the magazine 20.

A third alternative in station a shows a wound strand 136 of parallel filaments. The rope 136 is wound onto a take-up roll 138 and continuously unwound therefrom. The end of the rope 136 is inserted into an opening in the intermediate magazine 124 or the magazine 20 and then cut. The cut bristle tufts 24 are created after cutting the strand ends. For example, the movable X-Y table then moves the end of the spool or rope accommodated in the movable guide relative to the magazine 20 or the intermediate magazine 124, on the one hand, or the magazine 20/intermediate magazine 124 relative to the end of the rope, on the other hand, so that all the openings in the magazine 20 or the intermediate magazine 124 are filled in succession. In addition, multiple spools and ropes may be moved relative to magazine 20/intermediate magazine 124. The completely filled magazine 20 or the intermediate magazine 124 is then removed from this work station and transported into work station B or directly into work station C. In station B, the pusher 126 presses the bristle tufts 24 into the magazine 20.

To eliminate the X-Y table, the strands may be simultaneously fed from multiple rollers 138 to respective openings in magazine 20 or intermediate magazine 124 and then cut.

The workstation C is a so-called moulding station. The bristle tufts 24 are axially displaced in such a way that the rear ends of the bristle tufts (with which they are brushed) lie in a plane, or more generally end in a predetermined, arbitrary plane.

In the embodiment shown, a wave shape is specified beforehand, so that the stop plate 140 with a complementary wave shape is spaced apart from the magazine 20. The bristle tufts 24 are then pressed downward by a pressure plate 142, which preferably has a complementary shape to the surface of the stop plate 140, until all the bristle tuft ends rest against the stop plate 140.

However, when the desired shaping has been achieved in work station B by means of suitable pushers 126 of different or identical length, work station C can also be omitted if necessary. The two variants can also be combined with one another by so-called pre-shaping in station B by means of push rods 126 of different lengths and then finishing in station C by means of stop plates 140.

Station D is a shearing station in which the rear end of the bristle tuft is sheared in order to achieve an optimum melting of the end of the bristle tuft in the subsequent station. The bristle tufts 24, which may protrude to a varying extent at the rear side relative to the magazine 20, are sheared relatively close on the magazine 20 either mechanically by means of a blade 144 or thermally by means of a hot wire 146. If necessary, the magazine 20 may also function as a mating blade in the case of a mechanical blade 144. In this case, the bristle tufts 24 are slid slightly further out of the magazine 20 on the rear side after the cutting, so that they protrude slightly relative to the magazine.

If the bristle tuft end already projects at the rear side the same distance after the working stations B or C relative to the magazine 20, the working station D can be omitted if necessary. This is the case in particular if the bristle tuft ends on the front side should end in one plane.

The protruding sections of the bristle tufts 24 are then melted in the station E, so that all the filaments of a tuft are connected to one another, to be precise via the mushroom-shaped, thickened bristle tuft ends that are then produced. The thickness of the tuft ends is controlled by the amount of material on the filaments projecting on the back side relative to the magazine 20. Thereby also enabling the geometry of the ends of the bristle tufts to be adjusted.

The melting can be effected by a heated punch 148, which can touch the bristle tuft ends or can be spaced apart from them, so that the filaments are melted by radiant heat (in particular via infrared light). Alternatively, the melting may be achieved by hot air. The important points are as follows: only a single, configured thickening is always produced for the bristle tufts formed, since only those filaments which are then also to be fixed in the same fixing opening are to be connected to one another by melting. If necessary, the thickening 32 can be cooled here, as explained above.

In the subsequent working station F, the bristle tufts with their thickened fastening ends are moved forward into the fastening openings 12 of the bristle carrier 10 and pressed into them as already explained in detail above. This insertion can be done simultaneously, consecutively or consecutively in groups.

Further alternatives consist in: the reversing plate is provided with corresponding channels, into which the bristle tufts 24 are inserted with their thickened fastening ends in front, in order then to move on into the fastening openings of the bristle carrier. This variant is suitable if the subsequent hole pattern of the brush or the orientation of the bristle tufts 24 is not yet completely realized in the magazine.

The previously described individually manufactured, individual bristles 24' can be fed at will, either to the magazine 20 or to the bristle carrier 10 first, in each station.

Pressure is preferably applied to the holder 34, for example via at least one drive, for example an electric motor 240 (see fig. 1f), if necessary with an interposed transmission, for example a spindle nut 242. This is self-evident for all embodiments.

The electric motor is in particular a servomotor.

in general, the plurality of bristle carriers 10 can also be simultaneously deformed by the drive device in order to retain the at least one bristle or the at least one bristle tuft 24 in the fixed opening. To this end, the holder 34 has a plurality of recesses 38 shaped complementary to the bristle carriers.

In order to increase the production of the finished brush, in particular a plurality of drive devices are arranged next to one another, which in turn drive a plurality of holders 34, which in turn accommodate a plurality of bristle carriers 10.

The control system 51 is designed to be programmed accordingly, so that the above-described method is implemented in the device.

With the device according to the invention and the method according to the invention, it is possible to fasten very long and thin bristle tufts in a bristle carrier. The invention achieves a bristle carrier having bristle tufts with a length of more than 8mm and a width of less than 2mm, in particular less than 1 mm.

In the case of large edge lengths, it is not absolutely necessary to shape the respective edges of the fastening opening equally far inward. It has been demonstrated that: it is sufficient to provide some projecting edge sections which are deformed more inwards in the direction of the fixing opening, which edge sections alternate with edge sections which are deformed less inwards.

Claims

1. Method for producing a brush having a bristle carrier made of thermoplastic material, which bristle carrier has a front side and a rear side and at least one fastening opening, in which at least one bristle with a thickened fastening end made of thermoplastic material engages and is fastened without fasteners in such a way that the bristle protrudes from the front side of the bristle carrier, wherein the at least one fastening opening is delimited by an inner side and has on the front side an end-side edge which surrounds the fastening opening, characterized by the following steps: :

a) Providing a bristle carrier which, in the region of the end-side edge, has a transition edge to the inner side, which transition edge is chamfered at least in regions at the periphery of the transition edge, wherein the fastening opening and the transition edge are produced during injection molding of the bristle carrier,

b) receiving the at least one bristle in a receiving opening of the mould part,

c) While the at least one bristle is still in the receiving opening, the at least one bristle is moved with its thickened fastening end into a fastening opening in the bristle carrier which is formed during the manufacture of the bristle carrier,

e) The front side of the bristle carrier is brought to a temperature below the melting temperature of the bristle material and/or of the bristle carrier material, in particular up to 85% of the respective melting temperature of the bristle material and/or of the bristle carrier material in the case of c calculation,

f) The mould part exerts a pressure on the heated bristle carrier and deforms the bristle carrier in the region of the end-side edge surrounding the fastening opening with a reduced cross-section of the fastening opening, so that the at least one bristle is embedded and fastened in the fastening opening, wherein the material of the bristle carrier in the region of the edge and the inner side is pressed laterally into the fastening opening and into the region of the transition edge and against the at least one bristle, and

2. The method of claim 1, wherein: the chamfer extends along the entire periphery of the transition edge.

3. The method of claim 2, wherein: the chamfer has the same cross section along the entire circumference of the transition edge.

4. The method of claim 2, wherein: the chamfer has a different cross-section along the periphery of the transition edge.

5. The method of claim 4, wherein: the chamfer has different cross-sections along the periphery of the transition edge, which cross-sections originate from the same axial depth of the fastening opening, measured from the front side of the bristle carrier adjoining the chamfer.

6. The method according to any of the preceding claims, characterized in that: the chamfer starts in the fixing opening at a depth of at least 0.1mm and at most 0.5mm, in particular at most 0.35mm, from the front side of the bristle carrier adjoining the chamfer.

7. The method according to any of the preceding claims, characterized in that: the chamfer has a radial width of at least 0.1mm and at most 0.5mm, in particular at most 0.35 mm.

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

9. The method according to any of the preceding claims, characterized in that: adjoining fastening openings are separated by a web, which is provided with a chamfer at least toward one of the fastening openings, wherein the web extends as far as the front side of the bristle carrier and forms a section of this front side.

10. The method according to any of the preceding claims, characterized in that: the front side of the bristle carrier is a flat or convexly or concavely arched face.

11. The method according to any of the preceding claims, characterized in that: several fixing openings are provided, wherein at least some of the fixing openings each have a chamfer and the chamfers of the fixing openings are different.

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

13. the method according to any of the preceding claims, characterized in that: the material of the bristle carrier in the edge region and in the inner lateral region is pressed laterally into the fastening opening and in the region of the transition edge without protruding outward through the envelope formed by the front side of the bristle carrier.

14. The method according to any of the preceding claims, characterized in that: the thickened fastening end has a rounded or chamfered underside with which it is introduced into the fastening opening beforehand.

15. the method according to any of the preceding claims, characterized in that: the at least one bristle tuft is inserted with its thickened fastening end into the fixing opening in advance such that it does not come into contact with the chamfer of the fixing opening.

16. The method according to any of the preceding claims, characterized in that: the lateral dimension of the thickened fastening end is smaller than the lateral dimension of the correspondingly configured fastening opening in the base region of the fastening opening.

17. The method according to any of the preceding claims, characterized in that: the brush body is injected with the at least one securing opening and the at least one securing opening has an inner side with a draft angle for demolding after injection molding.

18. The method according to any of the preceding claims, characterized in that: the bristles or bristle tufts are inserted into the fastening openings at an angle to the front side, and the chamfer on the side of the transition edge which is closer to the bristles or bristle tufts is formed larger than on the remaining circumference of the transition edge, or there is no chamfer on the side which is further away from the bristles or bristle tufts and a chamfer is present on the transition edge in the remaining part of the circumference.

19. The method according to any of the preceding claims, characterized in that: the back side of the bristle holder is actively cooled during the application of pressure to the bristle holder.

20. The method according to any of the preceding claims, characterized in that: the bristle carrier has a plurality of attachment openings and the edges of these attachment openings are not provided with projections which project relative to the front side of the bristle carrier.

21. apparatus for manufacturing a brush having at least one bristle or at least one bristle tuft for carrying out the method according to any one of the preceding claims, the brush having a bristle carrier with at least one fixed opening for the at least one bristle or the at least one bristle tuft, characterized in that: the device comprises a plurality of work stations, wherein there are an injection station for producing the bristle carrier and a later fastening station for fastening the at least one bristle in the bristle carrier, wherein in the injection station there is an injection-molded half-module having at least one pin which projects into an injection cavity and which forms a section of the injection-molded half-module and which forms a fastening opening in the form of a blind hole, wherein the pin projects from the underside of the injection-molded half-module and is formed at the transition from the underside to the pin with a chamfer for forming a complementary chamfer in the region of the transition edge on the bristle carrier, and the device has a mold part which has at least one receiving opening for the at least one bristle or the at least one bristle tuft, the receiving opening opens out on the end face of the mold part facing the bristle carrier, and the mold part has a heating device for warming at least a section of the end face, which heating device is designed and set to heat the end face to a temperature of at most 140 ℃, in particular at most 130 ℃.

22. The apparatus of claim 21, wherein: the device is configured such that the mould part can exert a pressure of at least 200bar, in particular at least 400bar, on the bristle carrier.

23. The apparatus of claim 21 or 22, wherein: the chamfer on the transition between the pin and the base surface on the injection-molded half-mold has an axial length of at least 0.1mm and at most 0.5mm, in particular at most 0.35mm, and a radial width of at least 0.1mm and at most 0.35 mm.

24. Injection-molding half-module for manufacturing bristle carriers for an apparatus according to any one of claims 21 to 23, for carrying out a method according to any one of claims 1 to 20, characterized in that: the injection-molded half-mold has at least one pin which projects into the injection cavity and which forms a section of the injection-molded half-mold and which forms a fastening opening in the form of a blind hole, wherein the pin projects from the underside of the injection-molded half-mold and is formed at the transition from the underside to the pin with a chamfer for forming a complementary chamfer on the bristle carrier in the region of the transition edge, wherein the chamfer on the injection-molded half-mold at the transition between the pin and the underside has an axial length of at least 0.1mm and at most 0.5mm, in particular at most 0.35mm, and a radial width of at least 0.1mm and at most 0.35 mm.

25. An injection molding half-mold as claimed in claim 24 wherein: the injection-molded half-mold has an insert part made as a separate component, which projects into the opening of the remaining injection-molded half-mold and projects with a free end against the front side and thus forms a pin.