DE102010025852A1 - Method and apparatus for making brushes - Google Patents

Abstract

A method for producing brushes by means of a device comprises the following steps: Providing either at least one prefabricated base part (14) to which tufts of bristles (16) are attached and which forms a section of the finished brush, a separate part on the back of the base part (14) Support layer (30) is applied, or at least one prefabricated base part (14), which is formed by overmolding a plurality of bristle tufts (16) with previously fused bristle ends, feeding and positioning the bristled base part (14) to or in an injection molding tool, wherein each base part (14) rests in a cavity (46) of a mold half of the injection molding tool with its edge on the edge (50) of an opening (48) extending from the associated cavity (46) and the bristle tufts (16) protrude into the opening (48) , and rearward injection of a brush section onto the base part. A device for producing brushes is also described.

Description

The invention relates to a method and an apparatus for producing brushes.

Various methods of making brushes are known. Conventionally, a brush body is provided with an array of holes ("hole pattern" or "hole pattern") corresponding to the desired arrangement of bristles. Bundles or tufts of bristles are then inserted into the holes of the brush body and anchored therein by means of impressed small metallic anchors or by means of loops.

In an alternative method of making brushes which has become established within a few years, to which the present invention pertains, and which is referred to as Anchor Free Tufting (AFT), the bristle tufts become small Brush head plate (hereinafter referred to as "base part") attached without the use of loops or anchors, and the base part is then inserted or fixed in a brush body or a handle. In a variant of the AFT method brush handles are made with a hole pattern that corresponds to the desired tuft pattern. Bristle tufts are then inserted into these holes and attached to the brush handles. The attachment ends of the tufts are then covered with a small plate. This base part becomes part of the brush itself after the backside injection of plastic material.

An important and expensive step in the manufacture of brushes is the so-called bristling of the base part. In this case, a metal carrier part is used in the bristle machine, which has the same hole pattern as the base part and which serves as a guide and part holder for the bristle tufts. This support member is transported together with the bristled base part to the injection mold and acts there as a section of a mold half, which limits the cavity with a second mold half, is injected into the.

The bristle and the injection molding tool are coupled via the support plates with respect to the flow of material and timed to each other.

The object of the invention is to provide a flexible and cost-effective production of brushes.

• a) Vorsehen entweder wenigstens eines vorgefertigten Basisteils, an dem Borstenbüschel befestigt sind und das einen Abschnitt der fertigen Bürste bildet, wobei am Basisteil rückseitig eine separate Stützschicht aufgebracht ist oder wenigstens eines vorgefertigten Basisteils, das durch Umspritzen von mehreren Borstenbüscheln mit zuvor miteinander verschmolzenen Borstenenden gebildet ist,
• b) Zuführen und Positionieren des beborsteten Basisteils zu bzw. in einem Spritzgusswerkzeug, wobei jedes Basisteil in einer Kavität einer Formhälfte des Spritzgusswerkzeugs mit seinem Rand am Rand einer von der zugeordneten Kavität ausgehenden Öffnung aufliegt und die Borstenbüschel in die Öffnung ragen, und
• c) rückseitiges Anspritzen eines Bürstenabschnitts an das Basisteil.

This object is achieved by a method for producing brushes by means of a device, which is characterized by the following steps:

• a) providing either at least one prefabricated base part, are attached to the bristle tufts and forms a portion of the finished brush, wherein the base part back a separate support layer is applied or at least a prefabricated base member formed by molding over several bristle tufts with previously fused bristle ends is
• b) feeding and positioning of the bristled base part to or in an injection mold, wherein each base part rests in a cavity of a mold half of the injection mold with its edge on the edge of an opening of the associated cavity opening and the bristle tufts protrude into the opening, and
• c) back-injection of a brush portion to the base part.

The feeding and positioning of the bristled base parts to or in an injection mold is preferably carried out fully automatically.

The device according to the invention for producing brushes, in particular with a method according to the invention, is characterized by an injection mold having a mold half with at least one cavity for receiving a bristled base part, wherein the cavity has an opening for receiving a plurality, preferably all bristle tufts, and one the opening surrounding Abstützrand for supporting and supporting the base part.

By the invention, the effort required for the production of the carrier plates, significantly reduced because the carrier plates no longer migrate to the injection molding tool, whereby the timing of injection molding and bristle machine no longer necessarily be coupled together. Rather, the method according to the invention provides that no expensive perforated plate is provided in the injection molding tool. This perforated plate was previously used in the injection mold as a support for the relatively thin base plastic, to absorb the injection pressure. In the method according to the invention and in the device according to the invention, however, an opening (preferably a single opening) in the region of the cavity to be ejected is provided in a mold half of the injection molding tool into which the plurality of bristle tufts protrude. The base part is located exclusively or almost exclusively only with its peripheral edge on the edge of the cavity extending from the opening and is preferably supported only at this edge.

In order to withstand the injection pressure, according to an alternative prior to injection molding, back-injection molding of a separate support layer is required provided, which forms a prefabricated unit with the bristled base part and leads to an increased flexural rigidity.

The other alternative according to the invention provides for the bristle ends of the bristle tufts to first fuse together, which usually takes place in a perforated plate which is equipped with the bristle tufts and is expensive to produce. Subsequently, this perforated plate is transported in an injection mold to overmold the tufts. This results in a plate-like base part, in which the bristle tufts are positively and securely embedded at their point of fusion. In the prior art, this base part was always transported together with the carrier plate into a further injection molding tool or another station of an injection molding tool. The carrier plate served to support against the injection pressure during injection molding of the brush body (head and stem). However, the present invention provides that these provided with the hole pattern of the brush carrier plates when making the brush body no longer provide as support plates in the injection mold. Again, the base part is now supported at the edge of an opening in a cavity of the mold half. The Bürschel protrude into the opening, which is very easy to produce because of their size.

The invention relates, as stated, a nontacky production of brushes. The bristle tufts are not individually held in holes of a perforated plate by lateral interference fit, unlike the perforated plate in injection molding, but protrude freely in the opening of the mold half and are held by the base part.

The base part is preferably held at the edge in the cavity.

According to the preferred embodiment, the base part lies with its edge closed circumferentially on the likewise closed circumferential edge of the opening, so that a sealing effect is achieved.

The injection of the support layer is preferably carried out in a separate device or station, which is passed through before the final injection molding in the aforementioned mold half.

By the method according to the invention, in which the perforated plates no longer circulate between the boring machine and the injection-molding tool, the entire production and the entire apparatus can manage with significantly less perforated plates.

Of course, per base plate several base parts should be included, that is, a plurality of adjacent and possibly also in several rows positioned cavities are per perforated plate are provided.

It is now also possible to store the bristled base parts (before or after the application of the support layer) in a temporary storage or buffer storage. During maintenance work on the injection molding tool or the bristle machine, therefore, it does not come to a standstill of the other machine, which significantly increases the overall flexibility. In addition, the bristled base parts can also be purchased.

According to the preferred embodiment, the base parts remain support-free in the region of the opening during spraying. Alternatively, punctiform or linear support projections may press in the opening against the base member to support it during injection molding.

One of the preferred embodiments provides in this case that the support extensions to the base part conical, preferably even tapered. This allows them to slide between adjacent bristles without damaging the bristles.

According to a preferred embodiment, the tufts of the tufts projecting from the rear side (backside is the side with the fixed ends of the bristles) with respect to the bristles are glued or melted, e.g. B. by hot air, heat radiation or contact heat (pressing a hot tool). The contacting and flattening of the liquefied tuft ends is advantageous in that a dense, preferably closed surface of molten plastic is formed. This tightness is advantageous for the subsequent injection molding.

The support layer is preferably applied flat, that is, in the preferred embodiment, even over the entire surface. At most, the edge of the base part, with which it rests against the mold half, remains uncovered.

However, the support layer can also be formed in that the still unsecured bristle tufts are attached to the rear side by encapsulation by means of the support layer. In this embodiment, the step of applying the support layer simultaneously serves to attach the tufts to the base part.

Since the bristle tufts partially reach almost to the edge of the base part, it may be advantageous to use a so-called insertion tool on the injection molding tool. This insertion tool pushes the bristles slightly inwardly and together to facilitate easier insertion of the bristles into the common opening of the mold half. As a result, no bristles can get stuck on the edge of the opening and bend.

As already mentioned above, it is preferable to have a plurality of cavities in the mold half of the device according to the invention in order to increase the discharge rate of the entire device.

The mold half with the at least one cavity can also, and this is preferably formed in several parts. A first and a second molded part, if appropriate also further molded parts with in particular a plurality of juxtaposed cavities or rows of cavities, can be used. The cavity associated with a brush is then divided into several sections, for example into a section in the first and into a section in the second shaped part. These cavities merge into one another and form the total cavity of the mold half. However, the first molded part is separable from the second molded part and serves as a means of transport for or sitting in it base parts. Thus, the first molded part can be fitted independently of the second molded part first with the bristled base parts and only then be coupled to the second molded part, namely immediately prior to injection molding. However, since the first molded part is very easy to produce due to the lack of hole pattern, many first molded parts can be manufactured and used relatively inexpensively, which significantly improves the cycle time and flexibility of the entire device.

A separation station between the bristle machine and the injection molding tool can be provided to quickly clear the bristle machine again for equipping with base parts still to be bristled.

A coating tool, which may also be embodied as a single station in the then multi-station injection molding tool, should be positioned between the bristle machine and the injection molding tool, that is, possibly the station where the aforementioned spattering of the coated, bristled base part occurs. In this coating tool or in this coating station, the support layer is applied.

It should be emphasized that, according to the preferred embodiment, the so-called brush body is injection-molded in the injection molding tool, which can be designed in one or more parts. This brush body is usually the brush handle, the brush neck and a part of the brush head. The other part of the brush head is formed by the base part.

However, an embodiment is also conceivable, in particular for less expensive brushes, in which the base part itself already has almost the entire head and essentially the entire handle or handle of the brush. This base part is then covered on the back in several steps at least in the region of the head, namely first with the support layer in the region of the already fastened tufts and with an injection-molded cover-like part which covers the support layer. Of course, this part also forms a brush section.

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

1 a top perspective view of a bristle machine, which may be part of the device according to the invention for the production of brushes;

2 a plan view of a perforated plate in the bristle after 1 is used;

3 the perforated plate after 2 with inserted base parts before the bristles;

4 the view after 3 with bristled base parts;

5 a subsequent step after Beborsten for fusing the bristle ends;

6 a still open coating tool, in which the bristled base parts are provided on the back with a support layer;

7 the coating tool after 6 with the top removed after the application of the backing layer;

8th a subsequent process step, in which the bristled base parts are removed from the perforated plates;

9 a plan view of a molded part of an injection molding tool as part of the device according to the invention;

10 an alternative embodiment to 9 in which supporting projections additionally protrude into the opening of the molded part;

11 a perspective top view of a lower part of the device according to the invention in Area of the injection mold just before inserting the bristled base parts;

12 the base parts used in a molding;

13 a bottom view of the molding after 12 ;

14 a perspective view of the device according to the invention in the region of the injection mold when inserting the first molded part in a second molded part;

15 the opened injection mold after 14 after the injection process; and

16 to 19 several process steps of a slightly modified embodiment of the invention with a modified device.

In 1 is a so-called perforated plate 10 a device consisting of several tools and stations for the production of brushes. The perforated plate 10 is made of metal and preferably has several very precisely manufactured cavities 12 , in the prefabricated base parts 14 of brushes, here toothbrushes, are inserted. The basic parts 14 serve for anchorless attachment of bristle tufts. The basic parts 14 preferably have a circumferential, upwardly parked edge and a hole pattern for filling by the bristle tufts. Also the cavity 12 has a corresponding hole pattern. The production of such a cavity with hole pattern is very complicated and usually takes place by wire erosion or jig grinding.

In the so-called bristle machine, the base parts are then filled with bristle tufts, as z. B. in the EP 0974 646 B1 is shown. The perforated plate 10 serves as a transport body and also for the storage and management of bristle tufts, which protrude into the corresponding holes in the perforated plate. The portion of the bristle tufts protruding into the holes is the part of the bristles that later protrudes from the brush.

In 2 is the hole pattern of the perforated plate 10 to be seen from above.

3 shows the in the corresponding cavities 12 used basic parts 14 , where it is easy to see that the basic parts 14 exact and precise fit in the cavities 12 be recorded. There are numerous perforated plates are provided in the bristle machine, which are preferably equipped in or outside the bristle machine with the base parts and then beborstet. The perforated plates 10 are finally transferred to the bristle machine in another machine or in another station, including the bristled base parts contained therein, in order to carry out a further processing step can.

4 shows the bristled base parts 14 in the perforated plate 10 , where the bristle tufts 16 with its rear end opposite the base part 14 project upwards.

As already explained, either in the bristle machine itself, in a separate station or outside thereof in a fastening station, the bristles are provided at their projecting ends 16 attached to each other and also with the base part 4 get connected. This is done for example by means of thermal bonding of the protruding ends of the tufts 16 by hot air, radiant heat and / or by contact heat.

At the in 5 illustrated embodiment is an electrically heated tool with a plurality of heated punches 18 provided to a power source 20 are connected.

The cross section of the stamp 18 is that by the edge of the corresponding base part 14 adapted to circumscribed cross section.

Either the bristle ends 16 previously heated and brought to melting temperature so that they stick together, or the stamp 18 be down against the bristle ends 16 proceed and glue them together by merging.

Of course, the bristle ends 14 Also first brought to temperature and fused without the stamp contact them. Only then are the stamps 18 moved down to flatten the liquid plastic mass of the molten ends, so that a closed as possible plastic layer 22 from the molten material of the tufts. While it is advantageous to have a flat, closed layer 22 on the back of the base 14 but this is not mandatory. It could just as well individual thickening of bristle tufts 16 be present, resulting from the fusion of the individual bristles of a tuft of bristles.

6 shows another tool that can also be designed as a station of a larger device. This is a so-called coating tool.

The in the perforated plate 10 located bristled base parts 14 are preferably still in the perforated plate 10 to the in 6 transported coating tool shown and there in a lower part 24 an injection mold inserted. A shell 26 with adapted cavities 28 on its underside may be down against the bottom 24 be driven to the cavity 28 down through the corresponding base part 14 close, so that there is a cavity. In the corresponding cavities then a plastic compound is injected, which is the back of the bristled base part 14 preferably completely, if necessary, except for the peripheral edge, covers. This applied layer is a supporting layer 30 which is the unit of base part 14 and bristle tufts 16 gives a higher rigidity. The support layer 30 is in 7 to recognize.

In the next step, see 8th , the intermediates produced are in a separation station the perforated plates 10 taken. These intermediates can be stored in a store or stored unsorted, or they can immediately after their removal from the perforated plate 10 be transported to another machine, namely the injection molding tool explained below.

The injection mold is in 14 to recognize. It essentially comprises a lower mold half 40 and an upper mold half 42 , which each have cavities, which merge into each other in the closed state of the tool and form a cavity to be ejected. The lower half of the mold 40 comprises at least two parts, namely a first molded part 44 that the aforementioned and in 8th receiving intermediate products, and a second molding 46 , The first molded part 44 is in 9 good to see from above. It has several cavities 46 on each of which is an opening 48 going out to pick up the bristle tufts 16 a base part 14 serves. The edge 50 which is deepened and part of the cavity 46 is, surrounds the respective opening 48 , This edge 50 serves as support and support surface for the bristled base part 14 , Next to the edge 50 has the cavity 46 also a neck section 52 as a transition between brush head and later still shown brush handle.

This neck section 52 goes, how 14 shows, in the stem of the brush defining section 56 the cavity in the second molding 46 above.

In 11 you can see that the first molded part 44 is equipped with the prefabricated intermediates by an insertion tool 58 , which can consist of several movable on one another plates, is used. This insertion tool 58 may also be provided in the form of a funnel. The insertion tool 58 serves to the bristle tufts 16 inwardly toward each other to abut the marginal bristles on the edge 50 to prevent. Before completely introducing the intermediates in the appropriate cavity and opening 46 . 48 becomes the insertion tool 58 however removed.

The assembly of the first part 44 can preferably be done outside of the injection mold or in a lying before the injection molding station in the injection mold, as z. B. in the so-called helicopter tools according to z. B. DE 195 15 294 A or cube tools according to z. B. WO 2007/085063 the case is. With such tools, the assembly can take place during the injection process, with the tool closed. Alternatively, the assembly can take place in an open tool between two injection cycles. In this case, you lose some cycle time, as the tool must remain open a little longer after an injection cycle, until the assembly is completed.

In 12 is the stocked first molding 44 to recognize from above, in 13 from underneath. It is also apparent that the tufts 16 free in the opening 48 hang overhanging.

The first moldings 44 form transport parts for the bristled base parts 14 and transport them according to the associated second mold parts 46 , These moldings 46 have a recess 60 into which the molding 44 is used accurately. Subsequently, the injection mold is closed, and the injection molding process can take place.

After opening the injection molding tool (see 15 ) becomes the first molded part 44 with the molded-on brush body 62 taken from the injection mold, and the finished brushes are from the first molding 44 separated.

Of course, it would also be possible to inject several components one behind the other by the injection molding machine has even more stations for the other components. Again, the first molding 44 serve as means of transport between the stations.

In the injection molding process, in the aforementioned embodiment, all injection pressure is in the area of the base part 14 exclusively on the edge of the base part 14 with this this the edge 50 contacted, recorded.

Alternatively, it would also be possible from a bottom of the opening 48 outgoing or from the second molding 46 in the area of the recess 60 Outgoing upwards in the opening towards the base part 14 protruding outriggers 70 provided. The support extensions 70 are linear or, as shown, selective support points and run preferably to the base part 14 tapered to push between bristles.

In the embodiment of the 16 to 19 the base part is not made before the welding of the bristle ends, but afterwards. First, bristle tufts are made in a bristle tool 16 in holes of a perforated plate 10 with a corresponding cavity 80 for the later to be produced base part introduced ( 16 ). The upwardly projecting bristle ends of the bristle tufts 16 are merged together first. Subsequently, this perforated plate 10 transported in an injection mold to the tufts 16 to overmold. When the bristle ends are fused into a flat plastic plate and not a ball-like thickening, the base part becomes 14 essentially only sprayed, but what should also be covered by "encapsulation". This results in a plate-like base part 14 ( 16 and 17 ), in which the bristle tufts 16 at her thickened confluence 82 more or less positively and securely embedded (see cross-sectional view in 18 ). The present invention provides, these provided with the hole pattern of the brush carrier plates 10 during subsequent manufacture of the brush body (head and handle of the brush) no longer provide as support plates in the injection mold.

The bristled base parts 14 are rather of the perforated plates 10 separated ( 19 ) and either fed to a previously described storage / buffer and later or immediately according to the 9 to 15 further processed. The bristled base parts 14 So have to be in the first moldings 44 are inserted (eg fully automatic), and then transported to the injection mold. The injection molding process is carried out as described in the first Ausführungsbeipiel.

Again, the base part is at the edge of an opening 48 in a cavity 46 supported the mold half. The bailiff 16 protrude into the opening 48 , which is very easy to produce due to its size.

For all embodiments applies: The device for producing brushes may consist only of the injection molding tool or alternatively also from other tools such as the bristle tool and / or in the 6 and 7 shown coating tool. Separation stations and placement stations between individual tools or stations can be provided in which intermediate products of tool parts or carrier parts are removed or inserted into them.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 0974646 B1 [0050]
• DE 19515294 A [0065]
• WO 2007/085063 [0065]

Claims (14)

Method for producing brushes by means of a device, characterized by the following steps: a) providing either at least one prefabricated base part, are attached to the bristle tufts and forming a portion of the finished brush, wherein the base part back a separate support layer is applied, or at least a prefabricated base part, by overmolding several bristle tufts with previously fused bristle ends is formed, b) feeding and positioning of the bristled base part to or in an injection mold, wherein each base part rests in a cavity of a mold half of the injection mold with its edge on the edge of an opening of the associated cavity opening and the bristle tufts protrude into the opening, and c) back-injection of a brush portion to the base part. A method according to claim 1, characterized in that the base parts are removed from a bearing for bristled base parts and fed to the injection molding tool. A method according to claim 1 or 2, characterized in that the base parts remain free of support in the region of the opening during spraying. A method according to claim 1 or 2, characterized in that punctiform or linear support projections press in the opening between bristles against the base part to support it during injection molding. Method according to one of the preceding claims, characterized in that bristle tufts are inserted into receiving holes of the prefabricated base part in a bristle and that the bristle tufts are then attached to the back of the base anchorless, in particular by melting the bristles, gluing or encapsulation, wherein the base parts on perforated plates of Beeborstungsmaschine beborstet sitting, wherein the perforated plates have a hole pattern of the base parts corresponding hole pattern. A method according to claim 5, characterized in that after Beborsten and back-fastening of the bristle tufts on the base part, the support layer is applied flat, in particular by injection molding, wherein preferably at most one edge portion of the base part remains uncovered by the support layer. A method according to claim 5 or 6, characterized in that the application of the support layer takes place outside of the bristle machine and after or before removing the bristled base parts from the perforated plates. Method according to one of the preceding claims, characterized in that an insertion tool is provided, which compresses the bristles before or during insertion of the base part in the injection mold to insert them into the opening of the mold half. Method according to one of the preceding claims, characterized in that the bristle tufts are inserted into a perforated plate with the hole pattern of the brush to be produced and the bristles of the tufts are fused on the back and then, while still sitting in the perforated plate, are overmolded to form the base part, wherein the bristled base part is removed from the perforated plate before spraying the brush body to the base part. Apparatus for producing brushes, in particular with a method according to one of the preceding claims, characterized by an injection molding tool having a mold half with at least one cavity for receiving a bristled base part, wherein the cavity has an opening for receiving a plurality, preferably all bristle tufts, and one Opening surrounding Abstützrand for support and support of the base part. Apparatus according to claim 10, characterized in that a plurality of cavities are provided in the mold half. Apparatus according to claim 10 or 11, characterized in that the mold half is formed with the at least one cavity of several parts and having a first and a second mold part, both of which have merging sections of at least one cavity, and wherein the first mold part separable from the second and is designed as a transport part for the at least one base part. Device according to one of claims 10 to 12, characterized by a Beborstungsmaschine in the perforated plates and base parts are coupled together, wherein before the injection molding tool, a separation station is provided, in which the bristled base parts are separated from their associated perforated plates. Device according to one of claims 10 to 13, characterized by a coating tool which is positioned between the bristle machine and the injection molding tool and which applies on the back a support layer on the bristled base part.

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