JP3540023B2 - Method of manufacturing brush and brush manufacturing machine for performing the method - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a method of manufacturing a brush, in which the bristle bundle of the brush is connected to the brush body in an injection molding process, and in particular, the bristle strand is gripped on the outside and supplied from the bristle reservoir to the bristle housing. The present invention also relates to a method for cutting into a predetermined length in the hair bundle housing portion.
[0002]
Further, the present invention is a brush manufacturing machine for performing this method, comprising: a supply device for supplying a bristle bundle to a bristle holder provided with an accommodation portion for the bristle bundle; The present invention relates to a type provided with an injection molding die for coupling the brush body and the bristle bundle.
[0003]
[Prior art]
The following problems arise when manufacturing a brush in which the brush main body is injection-molded by an injection molding machine and the brush main body is coupled to the supplied bristle bundle. That is, when embedding the bristle bundle by injection molding under the influence of high injection pressure, the plastic material rises between each thread of the bristle bundle or between the perforated wall of the brush body and the bristle bundle, Protrusions and sharp edges may be formed on the manufactured brush. This makes such brushes unsightly and, in some cases, unusable. Particularly in the case of toothbrushes, such brushes can also damage the gums.
[0004]
Such undesired voids between each bristle yarn result from, on the one hand, the fact that the individual yarns are obliquely located, and, on the other hand, that the individual yarns are often wavy from the manufacturing process.
[0005]
Although the bristle yarn is slightly compressed when the bristle strand is introduced into the hole provided in the bristle accommodating portion, such a compressing action is caused by the feed pressure of the clamp gripper acting on the bristle strand on the outside. Because of its small size, it is small and thus does not solve the problems mentioned above.
[0006]
In the case of the method and the device known from DE 29 22 877, the introduction of plastics material into the bristle bundle during the injection molding operation is sought by: That is, such a bristle bundle is slightly compressed at the end on the brush body side by the conical constriction provided directly in the cavity of the mold.
[0007]
However, such a compression zone of the bristle bundle is short, and the compression pressure is limited only by the relatively small indentation forces that can be introduced, so that such a zone is located under high pressure. Can be plugged by the resulting plastic material, leading to the previously mentioned drawbacks of the brush and thus increasing the reject rate.
[0008]
Accordingly, a series of additional measures have also been taken to prevent the penetration of the plastic material into the area of use of the hair tress. For example, the housing opening is cooled when the injection molding material is introduced, or the bristle bundle is pushed into a slightly cooled non-pressure injection molding material.
[0009]
Further, a method is known in which the cross section of the accommodation hole for the hair bundle is partially narrowed after the introduction of the hair bundle, for example, by a collet chuck configuration.
[0010]
However, this requires a relatively large amount of work, especially in view of the large number of bristle bundles of the brush, and further in the case of a toothbrush, for example, considering that the bristle bundle diameter is small. Such a method is not very practical.
[0011]
[Problems to be solved by the invention]
The object of the present invention is to improve the method as described at the outset, so that a brush which has no penetrating injection-molding material residue in the area of use of the brush tuft and which can be manufactured easily is one-shot. An object of the present invention is to provide a method that can be manufactured in a molding process.
[0012]
It is a further object of the present invention to provide an advantageous brush making machine for performing this method.
[0013]
[Means for Solving the Problems]
In order to solve this problem, according to the method of the present invention, the bristle bundles located in the accommodating portion are shifted by applying a pressure load on the end face to reduce the bristle bundles in cross section and to close the bristle bundle yarns located next to each other. In order to guide them together, the bristle bundle was fed directly to a subsequent compaction device, and then the compressed or pre-compressed bristle bundle was fed to the injection mold.
[0014]
【The invention's effect】
The bristle tufts located in the receiving part can be loaded on the end face by a relatively large force. This is because these tufts do not displace laterally. Thereby, the shift of the hair bundle can be performed even if the pushing resistance to the compression device is increased. In this compression device, the bristle bundle is compressed substantially radially during feeding. By prefabricating the bristle bundle in this way, the bristle yarns come into intimate contact with one another and a compression is obtained such that penetration of the injection material can no longer occur during the injection molding operation. Such a compression step can be easily realized with little effort.
[0015]
According to another measure of the invention, a plurality of compressions of the bristle bundle are performed one after another in a stepwise manner inside the compression device.
[0016]
Experiments have shown that successive compressions lead to relatively small cross-sectional reductions in each case, which leads to better results.
[0017]
According to yet another aspect of the present invention, the contour of the bristle bundle is formed by shifting a part of the bristle bundle of the brush in the longitudinal direction simultaneously with the compression operation.
[0018]
Such contouring can be performed virtually in one operation during the compaction of the bristle bundle, so that no additional effort is required.
[0019]
In yet another advantageous measure of the invention, the compaction of the bristle bundle is made transverse to the longitudinal length of the bristle bundle, preferably approximately 5% to 20% of the bristle diameter, optionally Is performed in the range of 5% to 40%.
[0020]
In the brush-making machine according to the present invention for carrying out the above method, the hair bundle holder is followed by a compression device for the hair bundle, and the compression device is smaller than the accommodating portion provided in the hair bundle holder. At least one receiving section for the bristle bundle with a reduced cross-section, and a substantially direct transition for the bristle bundle from the bristle holder to the compression device is provided. A transport plunger is provided for loading and shifting the bristle bundle at the end face.
[0021]
From the bristle holder, the bristle bundles located in the bristle holder are conveyed directly to the adjacent compression device, where the bristle holder is loaded at its end face by a conveying plunger which engages the receptacle. . Due to the direct following of the compression device, the lateral displacement of the bristle thread can occur even with high pressure loads on the end faces, since the lateral guide for the bristle bundle continues to be obtained during the transfer operation. Absent. Therefore, the bristle bundle can be pushed into the receiving section having a suitably reduced cross section with a high pressure.
[0022]
According to an advantageous configuration of the brush-making machine according to the invention, the bristle holder and the compacting device each have a perforated plate with a through-hole forming a bristle receptacle, and these perforated plates are At the time of delivery, they match each other and overlap each other. Such a perforated plate is generally formed to be slightly thicker than the bristle bundle length, so that the transport plunger can slightly penetrate the perforated plate before loading the bristle bundle located on the transport plunger. These through holes make it possible to select a transport plunger which engages on both sides alternately, so that pick-up or delivery can take place on any side.
[0023]
In another advantageous configuration of the brush making machine according to the invention, the compression device has a plurality of perforated plates, into which the bristle tufts are successively introduced. Has a reduced cross-section for each perforated plate, and a transport plunger adapted to each cross-section corresponds to these perforated plates.
[0024]
Thereby, the number of compression steps and the respective compression scale can be varied over a wide range and can be adapted to the respective requirements.
[0025]
In a further advantageous embodiment of the brush-making machine according to the invention, the compression device has at least one stepped through-hole with a stepwise reduction in cross section in the pushing direction for the bristle bundle. It has a plate and corresponds to each stepped hole section with a suitable transport plunger which can be introduced in the transport direction.
[0026]
In this case, a gradual compression of the bristle tufts can be performed one after the other in only one perforated plate. Into these stepped hole sections are introduced transfer plungers corresponding to the cross section of each hole. That is, the cross-section is reduced for each hole, first the bristle tuft is pushed into the next narrowed hole section by the transport plunger with the largest cross section, and then adapted to such a narrower hole section. The hair bundle is further pushed in by the next narrowed transport plunger. At the other end of the perforated plate, an injection mold can be arranged directly for the delivery of the compressed bristle bundle.
[0027]
In a further embodiment of the brush maker according to the invention, at least one perforated plate and / or the injection mold of the compression device is connected to a vibration generator, preferably an ultrasonic generator.
[0028]
【Example】
Embodiments of the present invention will be described below in detail with reference to the drawings.
[0029]
1 and 2 show a supply device 2 for a hair bundle 3 and a compression device 4 in front of an injection molding machine 1. The material of the hair strands 6 is supplied to the hair holder 7 from the reserve roller 5. This is performed by the feed device 8. This feeder has through holes in three plates formed in layers. These through holes are arranged corresponding to the parts of the brush to be produced, which are later formed as hole fields. The feed device 8 is capable of reciprocating shift in the direction indicated by the arrow Pf1. The bristle strand 6 can be gripped and pulled out from the reserve roller 5. The holding of the strands takes place by laterally shifting the middle plate of the feeder, so that a clamp is created. The free end of the strand material is introduced into the bristle holder 7. This hair bundle holder has a perforated plate. The perforated plate has a perforated field with through holes 9 corresponding to the perforated field formed after the brush. Since the introduced strand section is cut by the cutter 10, the hair bundle 3 having an appropriate length is located in the hair bundle holder 7. The diameter of the through hole 9 provided in the hair bundle holder 7 is set so that the end of the strand material can be easily introduced into the through hole 9 from the feeder 8.
[0030]
The hair bundle holder 7 is associated with a number of transport plungers 11 on the side remote from the feed device 8, corresponding to the number of the hole fields.
[0031]
As can be seen in FIG. 2, for a first compression operation, the bristle holder 7 is shifted together with the transport plunger 11 corresponding to this bristle holder into the first perforated plate 12 of the compression device. You. This first perforated plate 12 has a perforated field which also matches the bristle holder 7. However, the diameter of the through hole 9a is slightly smaller.
[0032]
In the transfer position (FIG. 2), the perforated plate of the bristle holder 7 and the first perforated plate 12 of the compression device are closely adjacent to each other so that the through holes 9, 9a are aligned with each other. Positioned. By the transfer plunger 11, the bristle bundle located in the bristle bundle holder 7 is pushed out of the bristle bundle holder and pushed into the through hole 9 a of the first holed plate 12 having a reduced cross section. In this case, a relatively high pressing force is transmitted by loading the bristle bundle at the end face. This is because the bristle bundles are not displaced laterally during the transport process to the first perforated plate 12 of the compression device.
[0033]
The emptied perforated plate of the bristle holder 7 is then shifted again to its starting position (FIG. 1), and the second perforated plate 12a of the compression device is moved to the first perforated plate with the bristle 3 It is positioned before the plate 12. The movement of the perforated plate of the tress holder 7 and the movement of the second perforated plate 12a of the compression device can take place synchronously with each other, and accordingly the two perforated plates are connected to one another. You may. This requires only one positioning drive.
[0034]
The second perforated plate 12a of the compressor also has a through-hole 9b whose cross section is smaller than that of the first perforated plate 12. In these through-holes, the already pre-compressed bristle bundle 3 is shifted from the first perforated plate 12 of the compressor by the transport plunger 11a corresponding to this perforated plate 12. At this time, the hair bundle 3 is further compressed.
[0035]
Tests have shown that, depending on the bristle material used, two perforated plates 12, 12a of the compressor, which are used to obtain a sufficiently high compression of the bristle tuft, are sufficient. For example, the diameter of a toothbrush bristle bundle having a diameter of 1.5 to 2 mm is reduced by 0.1 to 0.3 mm per compression stage.
[0036]
If desired, more than two compression stages may be performed, and in some cases, only one compression stage may be performed. The second perforated plate 12a of the compressor, with the final compressed bristle bundle 3, is further supplied to the position of the injection molding machine 1 shown in FIG. When the compressed hair bundle 3 is introduced from the second holed plate 12a into the injection mold, further compression of the hair bundle 3 may be performed if necessary. In this case, the receiving hole of the injection mold is correspondingly reduced in cross section.
[0037]
At the transition from one perforated plate to an adjacent perforated plate, the through holes 9, 9a, 9b each have a conical transition ramp 13 as shown in FIG. ing. The fibers located on the outside are introduced into the through-holes, each having a reduced cross section, via such a conical portion.
[0038]
FIG. 4 shows the perforated plate 14 of the compressor. This plate with holes has a stepped through hole 15 whose cross section is reduced stepwise as viewed in the pushing direction (arrow Pf2). In this embodiment, three stepped hole sections 15a, 15b, 15c are provided. Conforming transport plungers 16a, 16b, 16c respectively correspond to these stepped hole sections.
[0039]
By means of the transport plunger 16a, the bristle bundle 3 located in the stepped hole section 15a can be shifted to the next stepped hole section 15b whose cross section has been reduced. The transport plunger 16a is then withdrawn and a further transport plunger 16b adapted to the stepped hole section 15b is introduced to shift the pre-compressed bristle bundle to the last stepped hole section 15c. This transport plunger 16c allows the compressed bristle bundle to be shifted from the perforated plate 14 of the compressor to the receiving hole of the injection mold or to the hole of another perforated plate of the compressor.
[0040]
This perforated plate 14 of the compressor, with stepped through holes 15, also corresponds to the subsequently formed flocking field, so that the complete set of bristle bundles belonging to one brush can be compressed here. It is advantageous to have a hole arrangement.
[0041]
FIG. 5 shows the supply device 2a. A pre-compression device 17 is provided at the supply device 2a. Through this pre-compression device, the hair strands 6 coming from the reserve roller 5 are pre-compressed and then supplied to the hair-bundle holder 7 in this pre-compressed state. Also in this pre-compression device 17, perforated plates 18, 18a having through-holes for hair bundle strands are arranged. In this case, however, these through holes are formed slightly conically narrow, so that a slight compression takes place when the strands penetrate. This pre-compression force, and thus the necessary indentation or pulling force, is such that the bristle bundle can be sufficiently fed by the pulling force transmitted by the clamping gripper of the feeder 8 acting on the bristle bundle on the outside. Is set.
[0042]
As indicated by the dashed lines, additional feeders 8a, 8b may be provided, as required, to cooperate synchronously with the feeder 8. By means of the precompression device 17, the bristle strands 6 are initially supplied to the perforated plate of the bristle holder 7 in a slightly compressed state, so that the number of subsequent compression stations can be reduced accordingly.
[0043]
To manufacture a brush, for example a toothbrush 19 (FIG. 6) with a continuous flocking field 20, it is advantageous if the bristle tufts are contoured simultaneously during the last compression operation. As shown in FIGS. 7 and 8, this is achieved by shifting a part of the yarn of one hair bundle in the longitudinal direction by applying a load on the transport plunger 21. These transport plungers have a contoured pressing surface 22.
[0044]
In order to better perform such a contouring of the bristle bundle 3 even in the state of being already significantly compressed, on the side facing the contoured transport plunger 21, it is contoured complementary to the transport plunger 21. A counter pressure plunger 23 having a counter pressure surface 24 may be provided. Since the counter pressure plunger 23 generates a counter pressure at the front end portion of the feed of the bristle bundle, the bristle bundle is pressure-loaded from both end faces for forming the contour. When the defined contour is achieved, the counter-pressure plunger 23 moves synchronously with the transport plunger 21.
[0045]
FIG. 7 shows the transfer plunger 21 and the counter pressure plunger 23 having a pressing surface or a counter pressure surface formed in a stepped manner. In contrast, in FIG. 8, these surfaces are shaped to form a conical tapering profile.
[0046]
The compressed and contoured bristle tufts 3 are then shifted into the receiving holes of the injection moulds 25, and the parts of these bristle tufts, which are later formed as fixed ends, are now in this position. It is located freely inside the 25 cavities. In order to avoid having to cut the corresponding contoured fixed end corresponding to the contoured working end in an additional work stroke, as shown in FIG. This fixed end is welded by a heating device, for example a heating plate 26, so that the fiber ends are joined together. As can be seen from FIGS. 9 and 10, this welding is performed up to the region where the contour forming portion or the corresponding contour forming portion ends.
[0047]
Instead of the heating plate 26, a hot air device 27 as shown in FIG. 10 may be used.
[0048]
If significantly different bristle bundles are used for one brush, only the bristle bundles having approximately the same cross-section as in feeding and compacting are processed in each case, whereby a perforated plate and a similar one are used. It is advantageous if the objects are formed in each case according to the same arrangement of hair bundles.
[0049]
Note that hair bundles with various cross-sections, such as circular, oval, square, star, etc., may be used. A through-hole and a suitable transport plunger are formed accordingly. Such shaping of the through-holes and the transfer plungers can be performed by a corrosion treatment.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a mechanism including a supply device and a compression device for a hair bundle.
FIG. 2 is a schematic diagram showing the mechanism of FIG. 1 in another working position.
FIG. 3 is a schematic view showing two adjacent perforated plates with through holes for hair bundles and their corresponding transport plungers.
FIG. 4 is a schematic diagram showing a perforated plate with stepped holes and different transport plungers corresponding to each hole section.
FIG. 5 is a schematic diagram showing the mechanism of FIG. 1 with a pre-compression device located at the supply device.
FIG. 6 is a partial side view schematically illustrating a toothbrush having a flocked field formed in an irregular shape.
FIG. 7 is a cross-sectional view schematically illustrating a perforated plate and a bristle bundle located on the perforated plate and contoured by a molded transport plunger.
8 is a cross-sectional view schematically showing a plate with holes and a bristle bundle located on the plate with holes and contoured by a transfer plunger formed into a shape different from that of FIG. 7;
FIG. 9 is a schematic diagram showing a bristle bundle located in an injection mold and a heating plate for welding a bristle bundle end.
FIG. 10 is a schematic diagram showing a bristle bundle located in an injection mold and a hot air device for welding the bristle bundle end.
[Explanation of symbols]
Reference Signs List 1 injection molding machine, 2 supply device, 3 bristle bundle, 4 compressing device, 5 reserve roller, 6 bristle strand, 7 bristle bundle holder, 8, 8a, 8b feeder, 9, 9a, 9b through hole, 10 cutter, 11, 11a conveying piston, 12 hole plate, 12a hole plate, 13 transition inclined portion, 14 hole plate, 15 stepped through hole, 15a, 15b, 15c stepped hole section, 16 transfer piston, 17 pre-compression device , 18 plate with holes, 19 toothbrush, 20 flocking field, 21 transport plunger, 22 pressing surface, 23 counter pressure plunger, 24 counter pressure surface, 25 injection mold, 26 heating plate, 27 high temperature air device, Pf1, Pf2 arrows

Claims (6)

A method of manufacturing a brush, in which a bristle bundle of a brush is joined to a brush body in an injection molding process, in particular, a bristle strand is gripped on the outside and supplied from a bristle reservoir to a bristle bundle receiving part, In the method of cutting the hair bundle (3) located in the housing part by applying a pressure to the end face, the hair bundle (3) is shifted by the end face to reduce the hair bundle in cross section and to remove the hair bundle yarns located side by side with each other. Feeding the bristle bundle to a compacting device (4) provided directly afterwards for tightly guiding together, and then supplying the bristle bundle, which has been compressed or pre-compressed, to the injection mold, How to make a brush. 2. The method according to claim 1, wherein the compaction of the bristle bundle is carried out several times in a stepwise manner inside the compaction device. 3. A method as claimed in claim 1 or 2, wherein the profile of the bristle bundle is achieved simultaneously with the compression operation by shifting a portion of the bristle yarn in the longitudinal direction. A brush-making machine for performing the method according to any one of claims 1 to 3 , wherein a supply device for supplying a bristle bundle to a bristle holder having an accommodation portion for the bristle bundle, and a brush. In the type in which the body is manufactured and an injection mold is provided for joining the brush body and the bristle bundle, the bristle holder (7) is provided with a compression device (4) for the bristle bundle. Wherein the compression device has at least one receptacle for the bristle bundle with a reduced cross-section compared to the reservoir provided on the bristle holder (7); There is provided a substantially direct transition for the bristle bundle from the bristle holder (7) to the compression device (4), and a transport plunger for loading and shifting the bristle bundle at the end face. A brush making machine, characterized in that: For brushes with different bristle bundles of cross-section, a plurality of apertured plate group having a number of through-holes corresponding to the number of the same tufts of each cross-section is provided, according to claim 4, wherein Brush making machine. Contour formed pressing surface (22) conveyed plunger (21) is provided with a, in this case, the transport plunger for introducing tufts into the injection mold are contoured, conveying plunger ( A brush-making machine according to claim 4 or 5 , wherein a counterpressure plunger (23) with a complementary contoured pressure surface (24) corresponds to (21) .

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