INTERDENTALBÜRSTE

Description

[0001] The present invention relates to an interdental brush according to claim 1.

[0002] US patent 3,698,405 discloses toothpicks with a plastic or metal shaft, wherein a rubber sponge coating is attached to the shaft along its entire length. Stubs may protrude from the surface of the rubber sponge. The rubber sponge is said to contain at least 70% air. In another embodiment, the rubber or rubber sponge is attached to the shaft only over a short distance at its ends.

[0003] Document WO 98 / 16169 discloses an interdental cleaner consisting of an elongated, rod-shaped carrier made of a first plastic material, the surface of which is partially covered by at least one insert or layer made of a second plastic material that is softer than the first plastic material. The insert can be arranged in a recess formed in the carrier and held in a form-fitting manner. If the first plastic material of the carrier and / or the second plastic material of the insert or layer contains one or more additives, the cleaning and care effect can be varied and optimized. To manufacture such an interdental cleaner, the second plastic material of the insert or layer is injection-molded onto the first plastic material of the carrier, whereby the carrier and the insert or layer can be produced using a two-component injection molding process.

[0004] Furthermore, a cleaning instrument for a tooth root canal, known from document EP 1 258 227 A, comprises a head section and an adjoining cleaning section with a shaft whose outer surface is provided with bristles. To ensure that the tooth root canal in particular can be reliably cleaned with the cleaning instrument, the shaft and bristles are formed as a single piece.

[0005] Document WO 2008 / 146968 A further discloses a method and a tool for manufacturing a mascara brush. The tool comprises an upper mold box and a lower mold box, which together, when closed, form cavities for producing the applicator heads by casting. For each mascara brush, a ceramic or plastic wick is placed in the lower mold box, and after the upper and lower mold boxes are joined, a soft material is injected into the cavities. For this purpose, the tool includes a pressure plate that interacts with the upper mold box, with feed passages leading from the space formed by the pressure plate and the upper mold box through the upper mold box and into the cavities. Material, which is liquefied under pressure, is placed between the pressure plate and the upper mold box.The material is liquefied by moving the press plate and the mold box towards each other, and the liquid material is forced through the connecting openings into the cavities.

[0006] JP2012-152928 A discloses a method for manufacturing an interdental brush. A plastic component for shaping the bristles is injected over a core, with the injection point being located at the tip of the core.

[0007] US2011 / 0041271 A1 discloses an interdental brush comprising a longitudinally defining bristle support stem with an elongated core, a bristle field with bristles projecting from the bristle support stem, and a neck element connecting the core to a handle, wherein the handle, the core, and the neck element are integrally injection-molded from a first hard plastic component, and wherein a second soft plastic component is applied to the core in the form of an integral layer with bristles projecting from it, the integral layer of soft material preferably being applied flush with the neck element to the core.

[0008] The purpose of this description is to propose a particularly simple injection molding process for the manufacture of a brush, in particular an interdental brush, which has a bristle support stem defining a longitudinal direction with an elongated support core and a bristle field with bristles protruding from the bristle support stem, a correspondingly manufactured brush, in particular an interdental brush, and a product group consisting of several brushes.

[0009] The brushes of the invention are interdental brushes. The object of the invention is achieved with an interdental brush according to claim 1.

[0010] Particularly preferred embodiments are specified in the dependent claims.

[0011] The description includes a method for manufacturing a brush, in particular an interdental brush, comprising a longitudinally defining bristle support stem with an elongated core, a bristle field with bristles projecting from the bristle support stem, and a neck element connecting the core to a handle, comprising the following steps: injection molding the handle, the neck element, and the core integrally from a first plastic component; inserting the core longitudinally through a bristle field cavity opening of an injection mold into a bristle field cavity; fixing the core inserted into the bristle field cavity to prevent longitudinal movement of the core; and applying a second plastic component from a injection point of the injection mold onto the core to integrally form a layer on the core and the bristles projecting from it; and a brush, in particular an interdental brush.comprising a longitudinally defining bristle support stem with an elongated core, a bristle field with bristles projecting from the bristle support stem, and a neck element connecting the core to a handle, wherein the handle, the core, and the neck element are integrally injection-molded from a first plastic component, and wherein a second plastic component is applied to the core in the form of an integral layer and the bristles projecting from it. The description further includes a product group comprising several brushes, in particular interdental brushes, wherein the handles of the adjacent brushes are each connected via one, preferably two, material bridges made of the first plastic component, and a product group comprising several brushes, in particular interdental brushes,wherein the handles of the adjacent brushes are each connected via a material bridge made of the first plastic component and a material bridge made of the second plastic component.

[0012] A product group consists of three to eight products arranged in a row, preferably five to six products. For the sake of simplicity, the figures are shown with only five products each.

[0013] The description further includes a method for manufacturing a brush, in particular an interdental brush, which has a longitudinally defining bristle support stem with an elongated core, a bristle field with bristles projecting from the bristle support stem, and a neck element connecting the core to a handle, comprising the following steps: injection molding the handle, the neck element, and the core integrally from a first plastic component in a first injection molding cavity; transferring the molded part into another cavity of an injection mold with bristle cavities; fixing the part inserted into the bristle field cavity to prevent longitudinal movement of the core; and applying a second plastic component from a injection point of the injection mold onto the core to integrally form a layer on the core and the bristles projecting from it.

[0014] The transfer in the injection mold preferably takes place with a transport bar, which moves the at least partially manufactured products from the cavity to another cavity after a lifting movement by means of a translational displacement or a rotation, where they are placed in the cavity by means of a lift.

[0015] The transport bar is preferably part of the cavity, meaning that the transport bar forms part of the molding geometry, at least in the first injection molding process. The interface between the product and the transport system can be located, for example, in the handle or the neck, or a combination thereof.

[0016] The often-desired individualization of the product can be achieved, for example, through interchangeable shaping parts in the handle or neck. This allows for the creation of lettering or other surface geometries. These elements can be positioned in the transport rail as well as in the actual cavity.

[0017] The manufacturing process of the aforementioned products is sufficiently complete after injection molding to produce usable products. Accordingly, the product can be packaged after injection molding.

[0018] The products are preferably packaged in a box that is presented to the end consumer. The products are arranged inside, either lying down or standing upright, directly adjacent to one another.

[0019] The packaging process can be integrated inline (i.e., linked together) or offline in a separate step. In the inline process, injection molding and packaging are coupled. The products are not removed from the machine until they are completely packaged. In the offline process, storage, transport, etc., take place after injection molding before packaging.

[0020] Furthermore, it is possible to perform intermediate steps after injection molding and before packaging. These include buffering or processing the product, for example by coating (spraying, dipping, etc.).

[0021] The first plastic component, from which the handle, the support core, and the retaining element are regularly integrally formed, is preferably a hard plastic. The second plastic component, from which the layer and the bristles protruding from it are formed, is preferably a soft plastic. It is also possible, for example, to use a third component in the handle area to increase grip and improve ergonomics, or in the bristle area in the form of additional cleaning elements or other functional elements. Examples of suitable materials in this context are listed below in the general description section.

[0022] Regarding the product groups, it should be noted that, in principle, each product can be manufactured in a single cavity and each product can be individually housed in the sales unit. Generally, several products are preferably arranged side by side and connected by material bridges in the handle area. The longitudinal axes of the brushes are preferably parallel. Typically, one, two, or three material bridges are provided (although more are conceivable). These primarily provide stability to the product groups. For use, the products are separated at the material bridges. Since edges can form when separating the individual brushes, which could injure delicate tissues such as the oral mucosa, the material bridges are regularly positioned in the handle. Preferably, the material bridges are each made of the same component.It is also possible to use two different or more different components, with one of each used for each material bridge. This depends, however, on the chosen injection points, with preferably only one injection point for each component per product group. It is further preferred that one material bridge is positioned towards the front and the other towards the rear of the handle to ensure sufficient spacing between them. The material bridges can have a rectangular or oval cross-section, preferably with one longer and one shorter length, the longer length preferably oriented along the longitudinal axis of the product. The material bridges can also include features to assist with the separation process, such as notches or perforations as predetermined breaking points.Regarding product design, it has proven practical to use the same colors, materials, and geometries for all products within a product group. However, it is also possible to design the products differently, for example, by varying the shapes of the cleaning tips. Different diameters, lengths of the cleaning tips, and overall brush lengths are also possible. Regarding the material, variations can be made in the second component (i.e., the soft component).

[0023] In a preferred embodiment of the present invention, the second plastic component partially encases the neck element.

[0024] This depends on the choice of injection points, but embodiments are also conceivable in which the neck element is completely encased by the second component.

[0025] In another preferred embodiment of the description, the supporting core, the neck element and the handle are injection molded in a cavity of the injection molding tool that is separate from the bristle field cavity.

[0026] In this way, the manufacturing process can be made more efficient than if a completely different injection molding tool had to be used.

[0027] In a further preferred embodiment of the description, the layer is designed such that it forms a sheathing of the supporting core in the area of ​​the bristle stem.

[0028] Such a sheathing allows for a particularly good and secure fit on the supporting core. In particular, the second component can also be selected with regard to its shrinkage behavior so that it shrinks onto the supporting core.

[0029] In another preferred embodiment of the description, the support core is centered in the bristle field cavity by means of bristle field tool parts, preferably by means of support elements projecting towards the interior of the bristle field cavity, at several longitudinally spaced support points.

[0030] The support points are preferably arranged between the bristles.

[0031] In this way, it can be effectively prevented that the supporting core moves in a radial direction (i.e. away from the longitudinal axis) and, if necessary, closes the openings for the bristles to be formed.

[0032] In yet another preferred embodiment of the description, the supporting core is preferably fixed in the area of ​​the handle at points where only a plastic component is present.

[0033] This is intended to prevent a second, possibly softer, plastic component from being damaged by the fixing agents.

[0034] In another preferred embodiment of the description, the first and second plastic components consist of a hard material, a hard material and a semi-hard material, or a hard material and a soft material.

[0035] The specific material combinations chosen depend on the particular application, and the materials used are detailed below in the general description section. For example, a PE-PE material pairing is suitable for a hard-semi-hard combination, where HDPE is used for the first material component and LLDPE for the second. A PP-TPE material pairing is suitable for a hard-soft combination.

[0036] The materials used can be water-soluble and edible, and thus be made entirely or partially from hydrocoloids, starch, gum arabic, polyvinyl alcohol, or polyoxymethylene oxide.

[0037] Furthermore, it is possible to spray on an additional material as a further component or to immerse the existing product in a bath and thus apply another component, for example as a coating.

[0038] Examples of substances that can be used as a coating or as an ingredient for the above-mentioned materials include color, flavor, dental cleaning fluid, toothpaste, and active ingredients.

[0039] Preferably, the supporting core has a smaller diameter than the neck element.

[0040] This ensures that the core is not too thick at its front end for use in the interdental area.

[0041] Preferably, the layer is also sprayed or applied flush with the neck element onto the supporting core.

[0042] The flush finish of the layer with the neck element is more comfortable to handle and offers a more visually appealing design.

[0043] In the present invention, the injection point of the second plastic component is located at the front end of the handle, facing the neck element.

[0044] The choice of injection point is generally determined by the product design, the shot weight, and the capabilities of the processing machine. Both hot runner and cold runner systems can be used. In conventional injection molds with a cold runner system, the gating system is not thermally isolated from the rest of the mold. Therefore, both the mold and the gating system within it are kept at temperatures significantly below the processing temperature of the plastic. As a result, the thermoplastic material solidifies even in the gating system during the production of a component.

[0045] In a hot runner system, the gating system is thermally separated from the rest of the mold and heated separately, ensuring that the molten plastic remains permanently fluid within the gating system. This prevents solidification of the plastic in the gating system, leaving no sprue on the component. Furthermore, hot runner systems allow for longer flow paths because the pressure drop in the gating system is not increased by cooling of the melt and the associated increase in viscosity.

[0046] Due to the aforementioned choice of injection point, the plastic component of the handle's casing covers a small portion of the surface, while on the back of the interdental brush, it covers a substantial portion of one side's surface at the neck element before finally covering the entire surface in the bristle field section. The parts injection-molded from the first plastic component (handle, neck element, and support core) may have corresponding recesses or channels that facilitate or support the flow of the second plastic component. Correspondingly identical injection molds are used for each. In this embodiment, the injection nozzle is located in the handle cavity, and a hot runner system is preferably employed due to the flow path.

[0047] In yet another preferred embodiment of the description, the injection point of the second plastic component is located at the free end of the support core or at the end of the support core facing the neck element.

[0048] If the injection point is located at the free end of the core, a separate injection point will be provided for each brush. A cold runner system is typically used, with additional means in the mold or during post-processing to separate the product from the gate. Generally, a punch or cutter is used as the release agent. The injection nozzles are thus located in the bristle field cavity, and a tunnel gate, a film gate, or other common gate types can be used.

[0049] In yet another preferred embodiment of the description, the injection point of the second plastic component is located at the rear end of the handle, facing away from the neck element.

[0050] Here, the spray nozzle is again located in the handle cavity. Due to the relatively long flow path, a hot runner system is typically used. The second plastic component covers a large portion of the handle surface, as well as a significant part of one side of the interdental brush's neck element on the back, before completely covering the surface in the bristle field section.

[0051] The second plastic component is received in corresponding recesses or a hole in the handle, where it forms a section with increased grip.

[0052] A corresponding recess in the handle can be textured, for example, with a structure on the edge or bottom of the recess. The shape of the texture can include bumps, grooves, ridges, or similar features, as well as combinations thereof. One or more components can protrude from one another; for example, hard components can protrude from soft components.

[0053] The recess can be designed with a two-component or three-component coating to further improve grip and ergonomics.

[0054] Furthermore, transitions may be provided, in the form of soft transitions from the handle, or sharply defined transitions from the handle, such as with a recessed area.

[0055] In principle, the troughs can be either closed or open, with the closed version having a continuous rim and the open version having at least one open side (for example, guides on the left and right along the longitudinal axis). It is also conceivable that the trough is open at both the front and rear.

[0056] Regarding embodiments with a hole in the handle, various configurations are conceivable. There can be one or more holes, for example, one large hole and several small holes. The holes are preferably circular or oval, but N-sided or polygonal holes (for example, with rounded corners) are also possible.

[0057] Furthermore, combinations of depressions and holes are also possible, such as holes within a depression.

[0058] Preferably, the supporting core has a round, triangular or trapezoidal cross-section.

[0059] The cross-sectional shape of the core typically depends on the specific bristle field geometry chosen. Furthermore, the core may be completely or partially enclosed by the sheathing or layer on one side (usually the bottom). On this side, the core will then have no bristles.

[0060] In another preferred embodiment of the present invention, the support core has a smaller diameter than the neck element, with the support core tapering towards its end facing away from the neck element.

[0061] The tapered design of the core and preferably also of the bristle stem ensures greater variability of the brush and may contribute to making it easier to insert the brush into the interdental area.

[0062] In a preferred embodiment of the description, the handle has a notch at its end facing away from the neck element, which is preferably provided with a rim made of a soft component.

[0063] The notch allows the brush to be attached to a holder, a glass, or a cup. The soft-touch rim improves grip and protects against scratches and damage.

[0064] Preferably, the bristles protrude non-radially from the longitudinal axis of the supporting core.

[0065] The individual bristles or rows of bristles are positioned primarily vertically from the longitudinal axis of the core, or they lie horizontally within a plane that passes through or below the longitudinal axis. This design improves the cleaning effect of the brush in critical areas between the teeth.

[0066] Furthermore, the bristles preferably decrease in length towards the end of the bristle stem furthest from the neck element.

[0067] This measure also serves to improve the cleaning effect in the interdental spaces, as the brush can adapt better in its shape.

[0068] In another preferred embodiment of the description, two rows of bristles extend substantially horizontally from the supporting core in a plane below the longitudinal axis of the supporting core.

[0069] In another preferred embodiment of the description, three rows of bristles are arranged on the upper side of the supporting core, which converge towards the end of the bristle stem facing away from the neck element and which preferably extend substantially vertically from the upper side.

[0070] These two measures create an optimally complementary bristle field geometry, enabling complete and even cleaning of the interdental spaces. The non-radial arrangement of the bristle rows enhances the cleaning effect compared to a radial arrangement.

[0071] In the present invention, the second plastic component is injection-molded onto the front end of the handle, which faces the neck element, wherein in a further preferred embodiment the second plastic component covers a small part of the surface on the handle, while on the back it covers a substantial part of the surface on the neck element and covers the surface of the supporting core completely, or except for a lower side.

[0072] In yet another preferred embodiment of the description, the second plastic component is injected onto the front end of the support core, the end facing away from the neck element, wherein the second plastic component completely covers the surface of the support core, or except for one lower side.

[0073] In a preferred embodiment of the description, two rows of bristles are arranged on the upper side of the supporting core, which converge in the direction of the end of the bristle stem facing away from the neck element and which preferably protrude from the upper side at an angle to the outside.

[0074] Here too, the two rows of bristles converge towards the free end of the core, and the length of the individual bristles decreases towards this end. This variant is even simpler to manufacture than the variant with three rows of bristles on the top of the core. It also results in a slightly different cleaning effect. In principle, however, the number of bristle rows is arbitrary, although two to nine rows are preferred, and three to five are even more so.

[0075] The angle between the individual rows of bristles is a maximum of 180°, i.e., the angle between the two furthest rows of bristles. In another preferred embodiment, the angle is between 0° and 90°. For the rows arranged in the middle (on the top side), the angle may be between 0° and 20°; for the rows arranged at the edge, the angle is preferably between 60° and 85°.

[0076] Suitable combination options with this product include additional cleaning and polishing elements, as well as other functional elements such as flossers (also called dental floss bows or dental violins), toothpicks, and tongue cleaners. Laminates made of the second material component can also be arranged on the core.

[0077] The lamellae can be integrated into the bristle field in various shapes. For example, the lamellae can run spirally around the core, or they can be arranged in a plate-like shape around the core. Multiple lamellae can also be arranged in this way. Furthermore, longitudinal lamellae extending along the longitudinal axis can be arranged. Lamellae can generally be straight or wavy, and the contour can be closed or open. Additionally, the lamellae can form a height profile.

[0078] The lamellae can be arranged in combination with the other cleaning elements mentioned; in particular, the lamellae can be arranged between the bristles.

[0079] Regarding the brush dimensions, a length of 35 to 70 mm is preferred, and a length of 40 to 55 mm is most preferred. The height (including the bristle area) is preferably between 0.8 and 2.8 mm, and most preferably between 1 and 2 mm. The width of the brush is preferably between 3 and 12 mm, and most preferably between 5 and 8 mm.

[0080] In a further preferred embodiment of the description, the second plastic component is injection-molded onto the rear end of the handle, the end facing away from the neck element, wherein the second plastic component covers a large part of the surface on the handle, while on the rear side of the neck element it covers a substantial part of the surface and completely covers the surface of the supporting core, or except for one lower side.

[0081] Furthermore, a brush, in particular an interdental brush, is provided comprising a handle, a neck element and a support core, wherein the neck element connects the handle and the support core and wherein a bristle field is applied to the support core, and wherein the handle has a notch at its end facing away from the neck part.

[0082] Preferably, the indentation is surrounded by two lateral flanks of the handle, which are further preferably designed to be flexible or spring-like in the form of clamping arms. The flexibility of the two clamping arms can be shaped by their geometry and / or by the selected plastic materials or material combinations.

[0083] The basic body, which in any case includes the handle and the neck element (these can, however, also be injection molded integrally with the supporting core), is regularly formed from a plastic component, preferably a hard material.

[0084] The indentation is preferably surrounded by a rim of a soft component to ensure better grip. However, the indentation can also be designed as a membrane with a soft component layer that forms a lip-like shape around the inserted object.

[0085] Furthermore, the surface in the area of ​​the indentation can be designed to include a recess for holding the brush. Additionally, surface elements such as slats, studs, or similar features can be arranged in the indentation area to further improve grip.

[0086] The indentation feature can be used in manual oral care devices in general, in addition to the application mentioned and described for interdental brushes. For example, it can also be used on other interdental cleaning devices, toothbrushes, flossers, etc.

[0087] In a further embodiment, a brush, in particular an interdental brush, which has a bristle support stem defining a longitudinal direction with a longitudinally extending support core and a bristle field with bristles protruding from the bristle support stem, is manufactured using injection molding.

[0088] For this purpose, a bristle field cavity, which serves to produce the bristle stem and the bristles, is closed. This is done by moving the tool parts of the injection mold that define the bristle field cavity into the closed position. The bristle field cavity, thus closed, has a bristle field cavity opening.

[0089] A support core, arranged longitudinally with its longitudinal extension, is inserted longitudinally through the bristle field cavity opening into the closed bristle cavity. Preferably, the inserted support core protrudes from the bristle field cavity opening with a section of it.

[0090] The supporting core inserted into the closed bristle field cavity is fixed in such a way that it cannot move in the longitudinal direction, i.e., shift.

[0091] By subsequently introducing plastic into the bristle field cavity, a layer of plastic is injected onto the supporting core, and the bristles are simultaneously produced integrally with the layer.

[0092] Fixing the support core prevents it from shifting longitudinally as a result of the force exerted on it by the liquid plastic.

[0093] Inserting the core into the already closed bristle field cavity has the advantage of preventing damage to both the injection mold and the core when closing the cavity. Inserting the core into the open bristle field cavity could, even with slight curvature of the core, cause it to become jammed in the injection mold during closing, thus damaging the mold.

[0094] Preferably, an injection mold is provided with at least two bristle field mold parts which, in the closed state, define the closed bristle field cavity. The bristle field cavity has a bristle field cavity opening on one end face. This opening is located longitudinally at one end of the bristle field cavity.

[0095] After the bristle field tool components have been brought into the closed position, the support core is inserted longitudinally through the bristle field cavity opening into the bristle field cavity and fixed in place by means of a fixing element. By injecting plastic into the bristle field cavity, the layer and the bristles are formed simultaneously on the support core.

[0096] Preferably, the layer is designed as a coating for the core such that the core cannot come into contact with the teeth when the interdental brush is used. This allows a metallic wire, for example made of spring steel, to be used as the core, thus preventing the risk of galvanic shock.

[0097] Preferably, the plastic is injected in such a way that it flows through the bristle field cavity opening into the bristle field cavity.

[0098] The end of the supporting core located in the bristle field cavity is preferably completely overmolded with plastic, so that the covering forms a kind of cap around the supporting core at the free end of the bristle support stem.

[0099] In a preferred embodiment, the support core is held – in the longitudinal direction – outside the bristle field to be formed by means of the fixing element, and the plastic is injected in such a way that it flows through the bristle field cavity opening into the bristle field cavity. The support core is thus held upstream in front of the bristles to be injected, which allows the support core to extend over at least approximately the entire length of the bristle field cavity without the risk of it being bent by the plastic flowing into the bristle field cavity.

[0100] For this purpose, the bristle field cavity can have a bristle field section and, in the direction of the bristle field cavity opening, a neck section immediately adjoining it.

[0101] Preferably, the support core is not completely rigidly fixed, but rather the fixation occurs at one section, in particular the end section of the support core, while the unfixed part can move radially within the bristle field cavity. This ensures fixation only axially.

[0102] In the bristle field section, that part of the interdental brush is manufactured which has the injected bristles and which is intended to be inserted into the interdental spaces when using the interdental brush.

[0103] The neck section can therefore be larger than the diameter of the bristle support stem in the bristle field section.

[0104] Preferably, the injection mold has at least one neck mold part, and the core is held in the area of ​​the neck mold part by means of the fixing element during the injection of the plastic. The neck mold part is located on the side of the bristle field mold part on which the bristle field cavity opening is located.

[0105] In another preferred embodiment, the injection mold has a cap mold part with a cap cavity which serves to form the layer, for example the coating at the free end of the bristle support stem.

[0106] Preferably, the cap tool part lies directly against the bristle field tool part.

[0107] The first tool part referred to here are the cap tool parts together with the bristle field tool parts and, if applicable, the neck tool parts and fixing element.

[0108] Preferably, two neck tool parts, when closed, form a neck cavity, the opening of which is positioned adjacent to the bristle field cavity opening during injection of the plastic. This enables the simultaneous and integral production of the layer or coating and the bristles together with a neck sheath or neck layer around the supporting core.

[0109] Preferably, the fixing element is formed by two clamping plungers which are diametrically opposed to each other with respect to the longitudinal direction and which can be moved from a rest position towards each other into a clamping position in order to hold the support core in a clamping position. Preferably, the direction of movement of the clamping plungers runs along a common straight line which is perpendicular to the longitudinal direction. The direction of movement is preferably parallel to the opening direction of the handle cavity and the neck cavity.

[0110] Preferably, the clamping plungers, in their clamping position, engage the interior of the neck cavity and are surrounded by the plastic during injection molding. Preferably, the clamping plungers seal against the support core in such a way that the plastic cannot flow into the clamping area when it flows around the plunger pair.

[0111] This results in the plastic component of the interdental brush having recesses created by the clamping pins, or a passage created by them, through which the supporting core runs.

[0112] Preferably, the support core is completely enclosed circumferentially by the clamping plungers when moved into the clamping position, so that a corresponding fixing section of the support core remains free of the plastic. In the resulting opening in the plastic component, the support core lies exposed without being encased by the plastic. Preferably, the support core is positioned so deep in the opening or recess that the risk of galvanic shock upon tooth contact is eliminated, as the teeth cannot touch it.

[0113] To achieve a particularly secure fixation of the support core, the clamping pins preferably have teeth or tooth gaps in the mutually facing end areas, which engage with each other in the clamping position.

[0114] Preferably, the supporting core in the bristle field cavity – in the bristle field section – is centered by means of the bristle field tool parts at several longitudinally spaced support points. For this purpose, the bristle field tool parts preferably have support elements projecting towards the interior of the bristle field cavity.

[0115] Preferably, the support elements protrude between 0.08 mm and 0.16 mm, and particularly preferably between 0.1 mm and 0.14 mm, from the outer surface of the part of the bristle field cavity defining the bristle support stem.

[0116] Furthermore, the support elements are preferably designed with respect to the core such that, measured radially, a gap of 0.01 mm to 0.03 mm, particularly preferably between 0.015 mm and 0.025 mm, remains between the support elements and the central or hypothetically central bristle support stem. This allows the core to be inserted longitudinally into the bristle field cavity and between the support elements without obstruction or bending. Furthermore, this enables the formation of a thin plastic skin on the core at the support elements during injection molding.

[0117] Viewed longitudinally, the supporting core is preferably supported by successive support elements at an angle. The offset is preferably 90°. This ensures that the support elements are spaced apart longitudinally and that no support elements face each other radially. The plastic can thus flow practically unimpeded from the bristle cavity opening through the bristle cavity, as its cross-section is restricted at most at one point. In this way, the support elements form support points that are spirally arranged around the bristle support stem.

[0118] Preferably, the support points are arranged such that the distance between two support points on the same side is between 4 and 16 times, preferably 4 times, a bristle spacing.

[0119] The last support point towards the free end of the supporting core is preferably located directly after the last bristle plane or directly in front of the last bristle plane.

[0120] The support points are preferably arranged regularly. However, it is also possible that the distance between the support points in the longitudinal direction is not always the same.

[0121] The support elements are preferably identical across the entire bristle field. Their number is determined by the length of the bristle support stem and the distance between the support points.

[0122] The support points or support elements are arranged in such a way that the bristle holes in the bristle field cavity cannot be closed by the supporting core, thus ensuring the formation of all bristles.

[0123] Bristle holes are understood to be those parts of the bristle field cavity which originate from the mantle surface that determines the bristle-bearing stem and serve to shape the bristles.

[0124] Preferably, the supporting core is formed by a metal wire, preferably made of a stainless or corrosion-resistant spring steel.

[0125] Steel grade 1.4310 is most preferred. The yield strength of the metallic wire should be greater than 2000 N / mm². This ensures good restoring torque when bending the bristle support shaft in the application and prevents the support core from breaking during repeated bending.

[0126] Alternatively, the supporting core can also be made of plastic, ceramic, or carbon composite fibers.

[0127] Plastic cores can be manufactured by injection molding or extrusion. A reinforced plastic is preferably used to achieve the necessary stiffness and hardness. Fiberglass or glass beads, for example, can be used to reinforce the plastic.

[0128] The injection molding or extrusion process for a plastic core is performed upstream of the injection molding process for the bristle field and can be separate or integrated into the same injection mold (two- or multi-component mold). The plastic core can have a shape different from that of a wire and define a significant portion of the handle and possibly its surface.

[0129] Preferably, the plastic is also used to manufacture a handle part of the interdental brush during the injection molding of the bristle field.

[0130] The handle part is injection molded in a handle tool part, which is also referred to here as the second tool part.

[0131] Preferably, for the aforementioned purpose, the injection mold has two handle mold parts which, in the closed position, form a handle cavity with an end-face handle cavity opening (second mold part). The bristle field mold parts, moved into the closed position, are moved together with the support core inserted into the bristle field cavity and held by the fixing element towards the handle mold parts, such that the end faces of the bristle field mold parts (or neck mold parts) and handle mold parts abut each other and the bristle field cavity opening or further neck cavity opening is located at the handle cavity opening.

[0132] The bristle field cavity, possibly together with the cap cavity and the handle cavity, possibly together with the neck cavity, thus jointly form an injection cavity for the entire plastic component of the interdental brush.

[0133] This embodiment allows the plastic to be injected into the handle cavity. It then flows through the adjacent handle cavity opening and bristle field cavity opening, via the neck cavity or the neck cavity openings, into the bristle field cavity. This avoids a injection point in the area of ​​the bristle field cavity.

[0134] It is also possible to inject the plastic directly into the bristle field cavity via a suitable injection point to produce the layer or coating and the bristles.

[0135] In this case, the bristle field cavity opening can serve as the closure of the bristle field cavity, so that a section of the support core protruding beyond the bristle cavity opening is not overmolded with plastic. This enables the production of interdental brush heads that can be attached to a separate handle in a known manner.

[0136] Accordingly, it is also possible that the further neck cavity opening forms the end of the injection cavity and that the supporting core protrudes through this opening, so that the protruding section is not overmolded with plastic.

[0137] The brush, in particular an interdental brush, which is manufactured in accordance with the method as further described, whether it has a handle or not, has a bristle support shaft defining the longitudinal direction, with an elongated, longitudinally extending core and bristles extending from the bristle support shaft. A layer of plastic is injection-molded onto the core or it is overmolded with plastic, the plastic integrally forming the layer or coating of the core and the bristles.

[0138] Preferably, a fixing section of the support core is at least partially exposed; at the exposed area, the support core is not covered by the plastic. This fixing section is preferably located outside the area where the bristles are located.

[0139] Preferably, the supporting core is partially exposed at support points or is only covered at these support points by a thin plastic film compared to the other areas of the plastic casing. It should be noted that these support points are defined by the support elements described above.

[0140] If an interdental brush uses a core made of electrically conductive material or a metal wire, the exposed areas are arranged in such a way that the core cannot come into contact with the teeth.

[0141] Preferably, the bristles extend radially from the bristle stalk.

[0142] Preferably, the bristles are arranged in rows extending longitudinally and evenly distributed circumferentially. Furthermore, and preferably additionally, the bristles are arranged in planes perpendicular to the longitudinal direction and spaced apart from one another longitudinally. Each bristle in a row is then also located in a plane.

[0143] The support points are preferably located between successive bristle planes.

[0144] It should be mentioned at this point that the corresponding form of the bristle field cavity is naturally defined by the above-mentioned arrangement of the bristles.

[0145] The injection mold has at least two bristle field mold parts that can be moved from an open to a closed state. In the closed state, the bristle field mold parts define a bristle field cavity for producing the bristle support stem and the bristles of the brush, in particular the interdental brush, by injection molding the plastic. In the closed state of the bristle field mold parts, the bristle field cavity has a bristle field cavity opening on one end face – and thus on one end face of the bristle field mold parts. A support core can be inserted longitudinally into the bristle field cavity through this opening. A fixing element is also provided, which serves to secure the support core inserted into the bristle field cavity.

[0146] Depending on the bristle arrangement, it may be necessary to provide more than two bristle field tool components, which form the bristle field cavity when closed. This avoids forced demolding.

[0147] Preferably, the injection mold has two handle mold parts which can be moved from an open position to a closed position. In the closed position, the handle mold parts define a handle cavity with a handle cavity opening, this handle cavity being used for injection molding a handle part of the brush, in particular an interdental brush. The bristle field mold parts, moved into the closed position, together with the support core inserted into the bristle field cavity and preferably already fixed with the fixing element, can be moved to the handle mold parts in such a way that the bristle field cavity opening and the handle cavity opening are connected to each other and the bristle field cavity, together with the handle cavity, optionally with a neck cavity, forms an injection cavity.

[0148] Preferably, a hot runner for supplying the liquefied plastic to the injection cavity opens into the handle cavity. The resulting injection point is preferably located in the handle of the interdental brush.

[0149] The bristle field tool components can define more than one bristle field cavity, each with its own bristle field cavity opening. This is particularly relevant when two cooperating bristle field tool components are sufficient.

[0150] A wire, particularly a steel wire, is preferably used as the support core. The diameter of the support core is between 0.1 mm and 0.4 mm, preferably between 0.15 mm and 0.25 mm. The length of the support core, depending on the length of the bristle support stem, is between 5 mm and 25 mm, preferably between 13 mm and 20 mm.

[0151] The length of the supporting core is preferably chosen such that it ends where the cap-like extension of the bristle support stem begins. However, it is also possible to make the supporting core long enough to form a uniform surface layer over its entire length.

[0152] The support core is preferably designed as a straight cylinder. The cross-section is preferably round, but it is also possible to design the cross-section as a regular n-gon, a T- or double-T profile, or to define another closed contour as the cross-section. It is important that the support core can be inserted into the closed bristle field cavity without any problems.

[0153] In principle, the support core can also be produced in a curved rather than straight shape, as long as it can be inserted into the closed bristle field cavity. A banana shape, for example, would be possible. However, since inserting the support core becomes more difficult, it is simpler to introduce any curvatures in the bristle support stem after injection molding.

[0154] In the area of ​​fixing the supporting core, it is also possible to give the supporting core a structure that improves the fixing.

[0155] For example, a snake shape or a helix, in short shapes that improve the clamping of the supporting core in conjunction with the possibly adapted fixing element.

[0156] The sheathing is designed to cover the free end of the supporting core like a cap. This means the steel wire, which is the preferred material, is not exposed at the surface.

[0157] Preferably, the core and thus the wire protrudes 3 mm to 12 mm, more preferably 4 mm to 6 mm, above the bristle support stem towards the handle. This preferably extends into the neck section.

[0158] On the side of the fixing element facing away from the bristle support stem (after the fixing element), the length of the support core or steel wire is 0.5 mm to 3 mm, preferably 1 mm to 2 mm.

[0159] In addition to the aforementioned metal, plastics such as PA or POM, or materials like Keflar can also be used for the supporting core. Generally, suitable materials are those that provide good resilience and do not break under repeated bending.

[0160] The core may have a special surface structure or surface treatment.

[0161] A smooth surface promotes sliding but can also have a negative impact, as, depending on the material combination, the core may break out of the casing due to relative movement between the two elements. Roughening the surface, for example, can improve adhesion between the plastic and the core material. This roughened structure can be achieved through etching, ridges, or other methods.

[0162] To achieve a rough surface, it is also possible to coat the surface of the core accordingly. Suitable materials include paints, adhesion promoters, or primers. It is important that the surface coating is not pushed away by the spray pressure or damaged by the heat generated during the process.

[0163] The thickness of the coating (measured outside the area of ​​the bristles and in the radial direction with respect to the longitudinal direction) is between 0.05 mm and 0.3 mm, preferably 0.1 mm and 0.2 mm.

[0164] Preferably the diameter of the bristle support stem (i.e., diameter without bristles) is 0.2 mm to 1.5 mm, preferably 0.35 mm to 0.9 mm.

[0165] The bristle support stem preferably has a length between 6 mm and 16 mm, particularly preferably between 9 mm and 13 mm.

[0166] The bristle support shaft preferably has a conical outer surface. The diameter at the free end of the support core is preferably 0.35 mm to 0.65 mm, and at the handle end of the bristle support shaft, preferably 0.65 mm to 0.85 mm.

[0167] The bristles, measured from the sheath to the free end, preferably have a length between 0.2 mm and 5 mm, more preferably between 0.5 mm and 3 mm.

[0168] The ratio of bristle diameter to the diameter of the supporting core is from 1:8 to 3:1, preferably from 1:2 to 3:4.

[0169] The ratio of the bristle diameter to the diameter of the bristle support stem is 1:30 to 3:2, preferably 1:6 to 1:3.

[0170] The sheath created by the bristle field (at the ends of the bristles) can take on a wide variety of shapes. For example, the bristles can form a straight circular cylinder or a cylinder with a triangular cross-section (fir-tree shape). Furthermore, shapes are possible where the cross-section changes along its length or is irregular at a certain point. This allows for the creation of wave-like or conical shapes. Shapes similar to those achieved with twisted brushes can also be realized in this way; in terms of complexity, there are more possibilities, as only the injection mold sets the limits.

[0171] The diameter of the bristles is preferably 0.05 mm to 0.3 mm, particularly preferably 0.1 mm to 0.2 mm - measured at the bristle stem, which is preferably rounded at the free end.

[0172] The bristles are preferably arranged in 2 to 10, particularly preferably 4 to 8, especially 6 rows of bristles, which run longitudinally and are evenly distributed circumferentially.

[0173] Furthermore, the bristles are preferably arranged in planes, the so-called bristle planes, which run perpendicular to the longitudinal direction and are arranged at a preferably constant distance along the longitudinal direction. It is also possible to arrange the bristle planes irregularly, i.e., to vary their distances.

[0174] An angle of preferably 45°, 60°, or 90° is formed between the longitudinal center planes defined by the bristles. This angle is regular across the entire cross-section of the bristle field due to the preferably regular arrangement of the bristle rows. An irregular arrangement, i.e., different angles between the bristle rows, is possible.

[0175] The distance between adjacent bristles, measured longitudinally and along the connecting line from the center of one bristle to the center of the other, is preferably between 0.2 mm and 0.8 mm, and in particular between 0.4 mm and 0.6 mm.

[0176] Preferably, 10 to 40, and in particular 18 to 30, bristles are provided in a row of bristles. In this way, between 22 and 400, and preferably between 100 and 150, bristles are arranged in the entire bristle field.

[0177] The outer diameter of the bristle field is preferably 1 mm to 6 mm, particularly preferably 1.5 mm to 4 mm.

[0178] The dimensions given for the sheathing and the bristles naturally also determine the dimensions for the bristle field cavity formed by the bristle field tool parts.

[0179] The parting line of the bristle field tool components preferably runs through the bristles of at least one bristle row. If four bristle rows are provided, the parting line preferably runs through the bristles of two diametrically opposed bristle rows. Particularly preferably, each bristle row is assigned a parting line, especially if more than two bristle field tool components are provided. This simplifies manufacturing, provides sufficient venting options for the bristles in the injection mold, and ultimately, the bristle lengths and diameters are not limited by the manufacturing process of the injection mold.

[0180] The clamping dies are preferably cylindrical in shape and have a diameter of 0.75 mm to 3 mm, particularly preferably 1.2 mm to 1.8 mm. This diameter also corresponds to the diameter of the recess or opening formed by the clamping dies in the neck area.

[0181] Other alternative cross-sections include oval or n-sided shapes. Round shapes are preferred for reasons related to plastic flow technology.

[0182] The clamping plungers preferably have teeth or clamping prongs at their opposing end regions, with a height of 0.4 mm to 2 mm, preferably 0.6 mm to 0.9 mm (this height is measured from the longitudinal axis 22). With respect to the longitudinal direction, preferably one tooth is provided on one side and two teeth on the other side. The other clamping plunger is designed in a mirror image, so that the teeth mesh together in the clamping position. More than three teeth per clamping plunger are also possible.

[0183] It is also conceivable that one clamping punch has two opposing teeth which engage in corresponding gaps between each pair of teeth of the other clamping punch.

[0184] The length of the fixing of the support core by the clamping punch or another fixing element is between 0.7 mm and 2.5 mm, preferably between 1 mm and 2 mm.

[0185] This length is preferably distributed regularly among the different elements, e.g., teeth, meaning they have the same widths. Alternatively, it is also possible to vary the widths.

[0186] The position of the fixing elements is preferably chosen such that the distance from the fixing element to the beginning of the bristle support stem is between 1 mm and 6 mm, preferably between 3 mm and 5 mm.

[0187] It is also conceivable to use a two- or multi-component injection molding process. For example, the coating or sheathing and the bristles can be made from one plastic, and the handle from another. Alternatively, the sheathing, bristles, and part of the handle can be made from one plastic, and the remaining part of the handle can be produced by injection molding on a second plastic. The second plastic can also cover exposed parts of the core.

[0188] Various plastics can be used to manufacture the brush, especially the interdental brush. The materials listed below can be used for a possible plastic core, the bristle field, the sheath, or the handle. Plastics that are bonded together using multi-component injection molding are preferred.

[0189] A plastic core is made of a harder plastic than the plastic used for the bristle field and the layer or sheathing or handle part.

[0190] Examples of possibilities from the field of thermoplastics include the following hard components: Styrene polymers such as styrene acrylonitrile (SAN), polystyrene (PS), acrylonitrile butadiene styrene (ABS), styrene methyl methacrylate (SMMA) or styrene butadiene (SB); polyolefins such as polypropylene (PP) or polyethylene (PE), for example also in the forms of high-density polyethylene (HDPE) or low-density polyethylene (LDPE); polyesters such as polyethylene terephthalate (PET) in the form of acid-modified polyethylene terephthalate (PETA) or glycol-modified polyethylene terephthalate (PETG), polybutylene terephthalate (PBT), acid-modified polycyclohexylenedimethylene terephthalate (PCT-A) or glycol-modified polycyclohexylenedimethylene terephthalate (PCT-G); Cellulose derivatives such as cellulose acetate (CA), cellulose acetobutyrate (CAB), cellulose propionate (CP), cellulose acetate phthalate (CAP) or cellulose butyrate (CB); polyamides (PA) such as PA 6.6, PA 6.10 or PA 6.12; polymethyl methacrylate (PMMA); polycarbonate (PC); polyoxymethylene (POM); polyvinyl chloride (PVC); polyurethane (PUR)

[0191] Examples from the field of thermoplastic elastomers (TPEs) include the following soft components: Thermoplastic polyurethane elastomers (TPE-U) Thermoplastic styrene elastomers (TPE-S) such as a styrene-ethylene-butylene-styrene copolymer (SEBS) or styrene-butadiene-styrene copolymer (SBS) Thermoplastic polyamide elastomers (TPE-A) Thermoplastic polyolefin elastomers (TPE-O) Thermoplastic polyester elastomers (TPE-E)

[0192] Furthermore, the thermoplastics polyethylene (PE) and polyurethane (PU) can be used as both hard and soft components, as mentioned above.

[0193] Ethylene vinyl acetate (EVA) can be used as a polyolefin in particular.

[0194] PP is particularly suitable as the hard component; PP with a modulus of elasticity of 1000–2400 N / mm², preferably 1300–1800 N / mm², is most preferred. A TPE-S is preferably used as the soft component. The Shore A hardness of the soft component is preferably below 90 Shore A. The soft components and the hard component are bonded together by overmolding in a two- or multi-component injection molding process.

[0195] Example materials for the production of injected bristles: Polyamide elastomer (e.g., Grilflex ELG 5930 from Ems-Chemie AG), polyester elastomer (e.g., Riteflex 672 RF Nat or Riteflex RKX 193 RF Nat from Ticona Polymers or Hytrel 7248 from DuPont), thermoplastic polyurethane elastomers (e.g., Desmopan DP 1092A, DP 3065D, DP 1092A from Bayer Material Science or Elastolan 1154 D, 1195 A from BASF)

[0196] The bristle materials have a Shore D hardness of 0 to 100, preferably 30 to 80, particularly preferably 50 to 70.

[0197] Bioplastics, which are plastics made from renewable raw materials, can also be used.

[0198] This method and such an injection mold can also be used to manufacture mascara brushes. In these brushes, the bristle field length is 8 mm to 30 mm, preferably 8 mm to 15 mm or 22 mm to 28 mm. The bristles are 1.5 mm to 3 mm long. All other dimensions can correspond to those of an interdental brush.

[0199] It is also conceivable to manufacture treatment heads for electrically operated interdental cleaners (toothbrushes) or for ear cleaners, pipe cleaners, bottle brushes and applicator brushes (medical sector) in the same way.

[0200] The cores are preferably introduced into the bristle field cavity by means of a feed and feeding device. This device can, for example, have a magazine with cores that are separated and then fed into the bristle field cavity, or a cutting device that cuts off core-forming sections from a long supply, which are then fed into the bristle field cavity.

[0201] Alternatively, the support cores are manufactured in a separate or integrated injection mold. A multi-component injection mold can be used.

[0202] The drawings depict various embodiments. They show purely schematically: Fig. 1 shows a perspective view of an interdental brush, which is not an embodiment of the invention; Fig. 2 shows a front view of the interdental brush. Fig. 1 Fig. 3 in top view of the interdental brush of Fig. 1Fig. 4 shows a rear view of the interdental brush. Fig. 1 Fig. 5 in underside view of the interdental brush of Fig. 1 ; Fig. 6 in side view in the direction of arrow VI of the Fig. 2 the bristle covering in the Figs. 1 to 5 interdental brush shown; Fig. 7 in the same representation as Fig. 2 , however, a portion of the interdental brush with the bristles is enlarged; Fig. 8 in top view and opposite Fig. 3 enlarges the same part of the interdental brush as Fig. 7 ; Fig. 9 in a cross-section between two bristle planes along line IX - IX of the Fig. 8 the interdental brush; Fig. 10 in a cross-section in a bristle plane along the line X - X of the Fig. 8 the interdental brush; Fig. 11 in a longitudinal section along line XI - XI of the Fig. 7the interdental brush; Fig. 12 in view and greatly simplified, a first part of the injection mold in the closed state and a second part of the injection mold with an open handle cavity and an injection-molded handle of an interdental brush located therein; Fig. 13 a longitudinal section through the injection mold along line XIII - XIII of the Fig. 12 with an interdental brush produced therein, wherein the second tool part is shown in a partially open position and the first tool part in its closed position; Fig. 14 a cross-section through the first part of the injection mold in the closed state with an interdental brush in a bristle plane along line XIV - XIV of the Fig. 13 ; Fig. 15 in perspective view a part of the first tool part with a bristle field cavity and a support core inserted into it; Fig. 16 in the same view as Fig. 15the part of the first tool section with an interdental brush injected into it; Fig. 17 in perspective view a part of the first tool section in the open state in a further embodiment; Fig. 18 in the same view as Fig. 17 the part of the first tool section also in the open state, but with an interdental brush manufactured in it; Fig. 19a in perspective view a first clamping punch for holding the support core in the injection mold; Fig. 19bein second clamping punch, the free end area of ​​which is opposite to that in Fig. 19aThe first clamping die shown is formed; Fig. 20 shows a view and schematic of the injection mold; Fig. 21 shows a flowchart for the production of an interdental brush; Fig. 22 simplifies a flowchart for possible further processing of the injection-molded interdental brush; Fig. 23 shows a perspective view of an embodiment of an interdental brush according to the invention; Fig. 24 shows a front view of the interdental brush. Fig. 23 ; Fig. 25 in rear view of the interdental brush of Fig. 23 ; Fig. 26 in side view of the interdental brush of Fig. 23 ; Fig. 27 in frontal view of the interdental brush of Fig. 23 ; Fig. 28 in a cross-section between bristle planes the interdental brush made of Fig. 23 ; Fig. 29 shows a cross-section between bristle planes of the interdental brush. Fig. 23In a further embodiment of the combination of core / sheathing or layer; Fig. 30 in front view a product group of interdental brushes according to Figs. 23-29 ; Fig. 31 in rear view of the product group of interdental brushes according to Figs. 23-29 Fig. 32 shows a further embodiment of an interdental brush from the front; Fig. 33 shows the interdental brush from the rear according to Fig. 32 ; Fig. 34 in side view of the interdental brush according to Fig. 32 ; Fig. 35 in rear view of a product group of interdental brushes according to Fig. 32 ; Fig. 36 in front view of a product group of interdental brushes according to Fig. 32 ; Fig. 37 in frontal view the composite group of interdental brushes according to Fig. 32 Fig. 38 shows a further embodiment of an interdental brush from the front; Fig. 39 shows the interdental brush from the rear according to Fig. 38 ; Fig. 40 in side view of the interdental brush according to Fig. 38 ; Fig. 41 in frontal view of the interdental brush according to Fig. 38 ; Fig. 42 in rear view of a product group of interdental brushes similar to Figs. 38-40 ; Fig. 43 in front view of the product group of interdental brushes similar to Figs. 38-40 Fig. 44 shows a front view of another embodiment of an interdental brush with overmolded wire; Fig. 45 shows a side view of the interdental brush according to Fig. 44 ; Fig. 46 in front view of a preferred embodiment of an interdental brush with overmolded wire.

[0203] The in the Figures 1 to 11The illustrated interdental brush 10 has a bristle field section 12, a neck section 14, and a handle section 16 with a handle 16'. A bristle support stem 18, from which bristles 20 protrude, extends, in this case in a straight line, over the entire length of the bristle field section 12 and defines a longitudinal direction 22; the dashed line indicating the longitudinal direction 22 also defines the longitudinal axis.

[0204] As this particularly affects the Figures 9 to 11Inside the bristle support stem 18, a removable, elongated support core 24 runs coaxially to the longitudinal axis 22. In the illustrated embodiment, this core is formed by a spring steel wire. It extends over the length of the bristle field 26 formed by the bristles 20 and over the neck section 14. In the area of ​​the bristle field 26, the support core 24 carries a layer 28, which here forms a sheath 28. This sheath, with a cap-like extension 30, encloses the free end of the bristle support core 24 facing away from the neck section 14. The sheath 28 is designed such that, when the interdental brush is used, the support core 24 cannot come into contact with the teeth or gums. The cap-like extension 30 is preferably formed as a continuous extension of the sheath 28.

[0205] The sheath 28 and the bristles 20 are injection-molded from the same plastic material as, in this case, the handle section 16 and, in the neck section 14 connecting the bristle field section 12 with the handle section 16, the neck sheath 32 surrounding the supporting core 24. The sheath 28 with the extension 30, the bristles 20, the neck sheath 32, and the handle section 16 forming the handle 16' are integrally formed and molded in a single injection molding step.

[0206] Of course, it is possible to use a two- or multi-component injection molding process, for example to form the bristle field section 12 and the neck section 14 with a first plastic component, to form the handle section 16 with a second plastic component, or, for example, to inject a second component, such as a soft component, into the handle section onto the part of the handle 16' formed from the first component, in order to improve the grip.

[0207] The bristle-bearing stem 18 is (slightly) conically widened from the extension 30 to the beginning of the neck section 14.

[0208] The bristles 20 are arranged in bristle rows 34 – in the illustrated embodiment, there are six bristle rows 34 – which extend longitudinally 22 and radially and are evenly distributed circumferentially. Furthermore, the bristles are located in bristle planes 36, which extend perpendicular to the longitudinal direction 22 and are spaced apart from each other in the longitudinal direction 22. Each bristle plane 36 contains one bristle 20 from each bristle row 34. For clarity, the bristle rows are shown only in Figure 6 marked with reference number 34 and are only available in Figure 8 Two bristle planes 36 are shown; in the illustrated embodiment, twenty-two bristle planes 36 are present.

[0209] The sheathing 28 has - in the illustrated embodiment - always straight grooves extending at right angles to the longitudinal direction, defining support points 38 and having a cross-section at least approximately semicircular, centrally located between each pair of adjacent bristle planes 36, wherein these support points 38 are arranged offset by 90° from space to space between each pair of bristle planes 36 in a direction of rotation.

[0210] Between the bottom of these grooves and the support core 24, there is at most a thin layer, a film of plastic. However, it is also conceivable that the support core 24 is exposed at the bottom of the support points 38. Due to the covering 28, however, it cannot come into contact with the teeth and gums.

[0211] As can be further seen from the figures, the free ends of the bristles 20 lie on the lateral surface of an imaginary cone, which widens (slightly) from the free end of the bristle field 26 in the direction of the neck section 14 and whose axis coincides with the longitudinal axis 22.

[0212] In the illustrated embodiment, the bristles 22 are circular in cross-section and tapered conically towards the outside in the radial direction, with the ends of the bristles 20 being rounded, here hemispherical.

[0213] The cone angle is between 1° and 2°. Other cross-sections for bristles 20 are of course possible; the limits here are the demoldability of the bristles 20 in the injection molding process.

[0214] Preferred dimensions for the bristle support stem 18, the bristles 20, the support core 24, the sheathing 28 and the formation of the bristle field 26 are given in the introduction.

[0215] It is also conceivable to design the bristle support stem 18 cylindrically, in particular circularly, and / or to arrange the free ends of the bristles 20 in the surface of an imaginary circular cylinder concentric to the longitudinal axis 22, or, as is the case in connection with the Figures 15 to 18 The image shows how to provide this feature in the lateral surfaces of two opposing cones. Other shapes are also possible.

[0216] The outer sheath 28 transitions continuously into the neck sheath 32 in the neck section 14, where the outer cross-section from the neck section 14 towards the handle section 16 continuously increases. Furthermore, in the free end region of the interdental brush 10, the outer sheath 28 transitions continuously into the cap-like extension 30.

[0217] The neck sheath 32 has a passage 40 extending perpendicular to the longitudinal direction 22, which in this case is cylindrical and through which the support core 24 runs centrally. This core is visible from the outside. Preferably, the handle-side end of the support core 24 is not located in the passage 40, but rather an end section of the support core 24 extends from the passage 40 towards the handle section 16 into the plastic from which the handle 16', the neck sheath 32, the casing 28 with the extension 30, and the bristles 20 are made; this is shown in particular Figure 11 .

[0218] In the illustrated embodiment, the handle section 16 or handle 16' is approximately the size of a fingertip, so that it can be easily held by the thumb and forefinger. Of course, the handle section 16 or handle 16' can be given any other shape, in particular, it can be made longer.

[0219] The Figures 12 to 14 greatly simplified, an embodiment of an injection mold 42 for producing the components described in the Figures 1 to 11 shown interdental brush 10.

[0220] The injection molding tool 42 has a first tool part 44 for the production of the bristle field section 12 and the neck section 14, and a second tool part 46 for the production of the handle section 16.

[0221] In the illustrated embodiment, the first tool part 44 is provided with six bristle field tool parts 48, which, in the closed state, define a bristle field cavity 50 for producing the sheathing 28, the bristles 20, and the cap-like extension 30. On one end face 52 – which faces a neck tool part 56 and thus the second tool part 46 – the bristle field cavity 50 has a bristle field cavity opening 54.

[0222] Furthermore, the first tool part 44 is associated with two beam-shaped neck tool parts 56, which – in the closed state – define a neck cavity 58. The neck cavity 58 has a first neck cavity opening 60 on the side facing the bristle field cavity 50, which – in the closed state of the injection mold 42 – is located at and aligned with the bristle field cavity opening 54; the neck tool parts 56 abut the end face 52. Furthermore, the neck cavity 58 has a second neck cavity opening 62 on the side facing away from the bristle field cavity 50 and towards the second tool part 46.

[0223] Furthermore, each of the neck tool parts 56 is assigned a clamping die 64. The clamping dies 64 are radially opposite each other with respect to the longitudinal direction 22, which is defined by the bristle field cavity 50, and are directed towards each other along a straight line that runs perpendicular to and intersects the longitudinal axis 22, from a rest position in which they are opposed to each other, into a position in the Figure 13 The clamping position shown is movable; this mobility is indicated by double arrows.

[0224] The clamping pins 64 together form a fixing element 64' for fixing the support core 24.

[0225] The second tool part 46 has two handle tool parts 66 which, in the closed state, form a handle cavity 68. For the sake of clarity, the Figures 12 and 13 Only one of the handle tool parts 66 is shown.

[0226] The grip cavity 68 has a grip cavity opening 70 on one side facing the neck cavity 58, which - in the closed state of the injection mold - is arranged adjacent to and aligned with the second neck cavity opening 62.

[0227] In the closed state of the injection mold 42, the bristle field cavity 50, the neck cavity 58 and the handle cavity 68 together form an injection cavity 72.

[0228] As is generally known and also from the information in the Figures 13 and 14As can be seen from the interdental brush 10 shown, the bristle field cavity 50 corresponds to the bristle field section 12 of the interdental brush 10, the neck cavity 58 corresponds to the neck section 14 of the interdental brush 10, and the handle cavity 68 corresponds to the handle section 16 of the interdental brush 10. The dimensions of these cavities 50, 58, and 68 are thus also derived from the dimensions of the interdental brush 10 given in the introduction. The shapes of the cavities 50, 58, and 68 result from the interdental brush 10 shown in the figures.

[0229] As this is particularly evident from the Figure 13 The removable part 46, which also shows an interdental brush 10 produced in the injection molding tool 42 when the second tool part 46 is opened on one side, is held firmly clamped during the injection molding of the plastic by means of the clamping punches 64 forming the fixing element 64'.

[0230] When the plastic is injected into the handle cavity 68, it flows through the neck cavity 58 into the bristle field cavity 50 without the supporting core 24 being displaced in the longitudinal direction 22.

[0231] Moreover, in the Figure 13 Support elements 74 are shown, which are formed on bristle field tool parts 48 and correspond to the support points 38 described in connection with the description of the interdental brush 10. The support elements 74 project towards the interior of the bristle field cavity 50 and thus form the support points 38.

[0232] How this will continue Figure 13 Since the bristle field cavity 50 is removable, in the closed state of the injection mold 42 it transitions continuously into the neck cavity 58 and this continuously into the grip cavity 68, thus forming the injection cavity 72. Of course, it is conceivable to form steps, grooves or channels at these transition points.

[0233] As this is evident from the Figure 14 As can be seen, the parting planes 76 of the bristle field tool parts 48 coincide with the longitudinal center planes 78 of the bristle rows 34.

[0234] Moreover, it shows Figure 14 the bristles 20 arranged in one of the bristle planes 36, which are integrally manufactured with the sheathing 28 of the supporting core 24 in the injection molding process.

[0235] In connection with the Figures 12 to 14 The basic principles of the procedure can already be discussed.

[0236] In the illustrated embodiment, the bristle field tool parts 48 are moved radially with respect to the longitudinal direction 22 into the closed state of the first tool part 44, whereupon they form the bristle field cavity 54, which has the bristle field cavity opening 54 on its end face 52. Then the (longitudinally arranged) support core 24 is inserted longitudinally 22 through the bristle field cavity opening 54 into the bristle field cavity 50 and subsequently held in place by means of the clamping punches 64.

[0237] In this process, either the support core 24 is first inserted into the neck tool part 56 and clamped, and then, by moving the neck tool part 56 towards the end face 52 of the bristle field tool parts 48, is inserted into the bristle field cavity 50, or the neck tool part 56 is moved towards the bristle field cavity 50, the support core 24 is moved through the neck tool part 56 into the bristle field cavity 50 and then clamped.

[0238] By injecting plastic into the bristle field cavity 50, the sheathing 28 and thus the bristles 20 are formed integrally.

[0239] The plastic is introduced into the bristle field cavity 50 through the bristle field cavity opening 54.

[0240] In the illustrated embodiment, the supporting core 24 is held centrally in the bristle field cavity 50 by means of the support elements 74, which are distributed in the circumferential direction and in the longitudinal direction 22.

[0241] In the illustrated embodiment, the clamping dies 64 are associated with the neck tool parts 56, which – in the closed state – define the neck cavity 58 connected to the bristle field cavity 50. Thus, the neck shell 32 is injection-molded simultaneously and integrally with the covering 28 and the bristles 20.

[0242] The clamping pins 64 are surrounded by the plastic and the opening 40 is formed in the neck sheath 32.

[0243] Furthermore, in the illustrated embodiment, a handle 16' of the interdental brush 10 is also formed. For this purpose, the first tool part 44, with the support core 24 inserted into the bristle field cavity 50 and held in place by the clamping plungers 64, is moved to the second tool part 46, so that the second neck cavity opening 62 is positioned at the handle cavity opening 70. With the handle tool parts 66 in the closed position and thus the handle cavity 68 closed, the plastic is injected into this cavity, which also enters the bristle field cavity 50 through the neck cavity 58.

[0244] To demold, the handle cavity 68 is first opened by separating the handle tool parts 66. Then, the handle 16' is removed from the area of ​​the handle cavity 68 by moving the first tool part 44 and the second tool part 46 away from each other. After moving the clamping plungers 64 from the clamping position radially outside the neck cavity 58, opening the neck cavity 58 by moving the neck tool parts 56 away from each other, and opening the bristle field cavity 50 by moving the bristle field tool parts 48 radially away from each other, the interdental brush 10 is completely demolded.

[0245] The Figures 15 to 18The figures show, in perspective, the first tool part 44 for the production of interdental brushes, as shown in the other figures and described above. The difference in the tool design compared to the figures already shown and described lies in the fact that the cap-like extension 30 is formed in a separate part of the first tool part 44 – a cap tool part 80. This tool part would be in Figs. 15 and 16 visible, but not shown for the sake of clarity.

[0246] The differences on the product side consist of the design of the bristle field 26 and the shape of the handle 16'. All bristles 20 are arranged in six circumferentially uniform rows 34, and all bristles 20 are located in bristle planes 36, which are arranged at a constant distance from one another in the longitudinal direction 22. In each bristle plane 36, there is one bristle 20 from each bristle row 34. However, the free ends of the bristles 20 are no longer located on a single conical surface, but rather they terminate in two oppositely directed conical surfaces, which extend with their smaller diameter from the axial ends of the bristle field 26 and meet at least approximately in the middle.

[0247] Of course, other configurations of the bristle field 26 are also possible with the injection mold 42 shown, including those in the Figures 1 to 11shown; only the bristle field cavity 50 needs to be designed accordingly.

[0248] Furthermore, how this affects the Figures 16 to 18 The handle 16' is removable and cuboid in shape with rounded edges. The handle cavity 68 formed by the second tool part 46 is shaped accordingly. Otherwise, the design is the same as in connection with the Figures 12 to 14 discussed.

[0249] Figure 15 Figure 1 shows three of the six bristle field tool parts 48 in perspective, which are in the closed state. The remaining three bristle field tool parts 48 and also the cap tool part 80 are not shown in order to allow a view into the interior of the injection mold 42. Furthermore, the Figure 15One of the two beam-shaped neck tool parts 56 is shown, which, in the closed position of the second tool part 46, rests axially against the bristle field tool parts 48 dh of the end face 52, such that the bristle field cavity opening 54 is located at the first neck cavity opening 60. Further details are shown in Figure 15 One half of the neck cavity 58 is shown, into which the clamping plunger 64 associated with this neck mold part 56 projects. The two neck mold parts 56 (excluding the clamping plungers 64) are shaped identically, at least at the interface, and define the neck cavity 58 when the injection mold 42 is closed. This identical shaping is advantageous to ensure uniform filling during the injection molding process when the plastic is introduced.

[0250] On the side of the bristle field tool parts 48 facing away from the neck tool part 56, the cap tool part 80 rests against them, which forms a cap cavity 82 for shaping the extension 30, which covers the free end of the support core 24, during the injection of the plastic; see also Figures 1 to 11 The cap tool part 80, or the cap cavity 82, is preferably formed in one piece. This means that the cap cavity 82 is designed as a blind hole and demolding is only possible in the longitudinal direction 22. Therefore, this part is moved away from the bristle field tool parts 48 in the longitudinal direction 22 during the process before the bristle field 26 can be extended from the remaining first tool part 44.

[0251] Furthermore, in the Figure 15the supporting core 24 is shown, which has been inserted through the neck cavity 58 and the bristle field cavity opening 54 into the bristle field cavity 50 in the longitudinal direction 22, after the bristle field tool parts 48 have been brought into the closed state.

[0252] Furthermore, in the Figure 16 Dovetail-shaped guide slots 96 for the bristle field tool parts 48 are shown. The associated radial guides 84 are formed on a support body 86, the structure of which also includes the Figures 17 and 18 can be removed.

[0253] For the sake of completeness, it should be mentioned that the parting planes 76 are in turn located in the longitudinal center planes 78 of the bristle rows 34. Furthermore, bristle field tool parts 48 have support elements 74 (compare Figure 14 ), which serve to center the supporting core 24 in the bristle field cavity 50.

[0254] The Figure 16 shows in the same representation as Figure 15an interdental brush 10 produced in the injection mold 42. In the passage 40 in the neck sleeve 32, which is kept free of plastic during injection molding by the two clamping punches 64, the exposed fixing section 88 of the support core 24 is located (see also Figures 2 , 4 , 7 , 11 and 14 ) and on the other hand, one clamping plunger 64 is visible, which is still shown in clamping position.

[0255] In the Figure 17The first tool part 44 is shown in the open state. The cylindrical support body 86 has (on its end face 52) a face plane 90 extending perpendicular to the longitudinal direction 22, which faces the neck tool parts 56. The support body 86 has six guide grooves 92 extending radially in the longitudinal direction 22 and evenly distributed circumferentially, in this example, which are open in the face plane 90. A bristle field tool part 48 is inserted into each of these guide grooves 92 and is mounted therein so as to be displaceable in the radial direction.

[0256] In the Figures 15 and 16(Not shown in the figures) the side surfaces of the guide grooves 92, which bear against the side surfaces 94 of the bristle field tool parts 48, are provided with dovetail-shaped radial guides 84. For the sake of completeness, it should be mentioned that the bristle field tool parts 48 naturally have correspondingly shaped guide slots 96 into which the radial guides 84 engage. The aforementioned guide slots are in Figs. 15 and 16 shown.

[0257] In the Figures 17 and 18The radial guide slots 96 (one guide slot 96 per guide groove 92 and side surface 94), which have a dovetail-like undercut, are formed from a base 98. The correspondingly shaped radial guides 84 of the support body 86 are guided in these guide slots 96 of the bristle field tool parts 48, with each bristle field tool part 48 having two guide slots 96; only one is visible in each figure.

[0258] In the embodiment ( Figures 15 to 18 The task of the combinations consisting of guide slots 96 and radial guides 84 is to hold the bristle field tool parts 48 in the support body 86 in the axial direction with respect to the longitudinal direction 22 and to guide them translationally in the radial direction.

[0259] The bristle field tool parts 48 are cuboid in shape, with the following in the Figures 15 to 18In the embodiment shown, each of the two opposite sides (broad sides) is provided with the guide slots 96.

[0260] In the radially inward end region, the bristle field tool parts 48 are shaped like gables, with the gables 100 extending in the longitudinal direction 22 and the roof surfaces 102 forming the parting planes 76. That is, in the closed state, the roof surfaces 102 of adjacent bristle field tool parts 48 lie against each other. In the closed state of the bristle field tool parts, the gables 100 together form that part of the bristle field cavity 50 which forms the bristle support stem 18.

[0261] The roof surfaces 102 have corresponding groove-like recesses which, in the closed state of the bristle field tool parts 48, form the part of the bristle field cavity 50 associated with the bristles 20. The roof surfaces 102 thus form part of the bristle field cavity 50.

[0262] In the radially outer end region, the bristle field tool parts 48 have dovetail-like guide projections 104 which, in their imaginary extension with the longitudinal axis 22, form an acute angle. The guide projections 104 are guided in opposing sliding grooves of a control ring, which surrounds the support body 68 and can be moved back and forth axially by means of a drive element. In one axial end position of the control ring, the bristle field tool parts 48 are abutting each other in the closed state and form the bristle field cavity 50, as shown in the Figures 15 and 16 Shown reduced. In the other end position of the control ring, the bristle field tool parts 48 are located radially outside in an open position, as shown in the Figures 17 and 18 shown.

[0263] As this can be seen from the Figures 17 and 18 compared to the Figures 15 and 16As can be further seen, the neck tool parts 56 are mounted to be displaceable in the longitudinal direction 22 relative to the bristle field tool parts 48 and also to the support body 86; longitudinal mountings are generally known and are not shown for the sake of clarity. Drive elements for the movement of tool parts are also generally known and are not shown.

[0264] In Figure 18 The first tool part 44 is also in the open position, however, in addition, as in Figure 16 An interdental brush 10 produced with the injection mold 42 is shown. This is still held by the neck tool parts 56, which are still in the closed position, although only one of the neck tool parts 56 is shown.

[0265] The operating principle of injection mold 42 is described further below in connection with the Fig. 21 described.

[0266] The Figures 19a and 19bshow a preferred embodiment of the two clamping plungers 64 forming a fixing element 64'.

[0267] The clamping punches 64 have 110 teeth 112 and oppositely shaped tooth gaps 114 in their mutually facing end regions, wherein in clamping position the teeth 112 engage in the tooth gaps 114 of the respective other clamping punch 64.

[0268] In the illustrated embodiment, the clamping punches 64 have a circular profile cross-section, wherein the ends facing each other are provided with a punch recess 116 that is v-shaped in cross-section and extends in the longitudinal direction 22.

[0269] In the base of the punch recess 116, the clamping punches 64 each have a groove 118 extending in the longitudinal direction 22, wherein the two grooves, in the clamping position of the clamping punches 64, essentially correspond to the outer contour of the support core 24, but are designed in such a way that, in the clamping position of the clamping punches 64, the support core 24 can be held clampingly by the grooves 118.

[0270] At the in Figure 19a The clamping die 64 shown has flanks 120 formed by the die recess 116, divided centrally in the longitudinal direction 22 into two teeth 112 each by a transverse recess 122. The transverse recesses 122 form tooth gaps 114 in the flanks 120, which correspond to the teeth 112 shown in the Figure 19b The clamping die shown is formed with 64 teeth 112.

[0271] During the Figure 19bIn the clamping die 64 shown, the two flanks 120 formed by the die recess 116 are shaped into teeth 112 each by two transverse recesses 122 located on the outside in the longitudinal direction 22. These transverse recesses 122 are opposite to the teeth 112 of the clamping die 64 shown. Figure 19a The clamping die shown is shaped like 64.

[0272] When the two clamping plungers 64, which lie on a common axis, are moved towards each other, the two teeth 112 of the in the Figure 19b The clamping stamp 64 shown engages with the tooth gaps 114 of the tooth gaps in the Figure 19a The clamping die 64 shown. Accordingly, the four teeth 112 of the in the Figure 19a the clamping stamp 64 shown into the outer tooth gaps 114 of the in the Figure 19b The clamping plunger 64 shown is engaged.

[0273] In the clamping position, the support core 24 in the fixing section 88 is thus completely enclosed by the clamping pins 64. Furthermore, in the clamping position, the two clamping pins 64 form a continuous profile, which serves to create the opening 40 during injection molding.

[0274] The Figure 20 Figure 1 schematically shows a possible embodiment for the injection molding tool 42 with a single stationary second tool part 46 and four second tool parts 46, which are rotatable about a rotary axis 124 and can be moved successively to the second tool part 46 after a rotation of 90°.

[0275] The second tool part 46 has the two handle tool parts 66, which, in the closed state, form the handle cavity 68. It should be noted here that the first tool parts 44 and the second tool part 46 can each form several corresponding cavities in order to produce several interdental brushes simultaneously, as is generally known from toothbrush production.

[0276] Each of the first tool parts 44 has, on the side facing the second tool part 46, two neck tool parts 56 which, in the closed state, form the neck cavity 58 or neck cavities 58. On the side facing away from the second tool part 46, each first tool part 44 has a cap tool part 80 with the corresponding cap cavity or cap cavities 82. Between the neck tool parts 56 and the respective cap tool part 80 are the bristle field tool parts 48. The first tool parts 44 are designed as described above and shown in the preceding figures. The neck tool parts 56 are movable relative to the bristle field tool parts 48 in the direction of the double arrow shown – thus in the direction of the axis of rotation 124 or the longitudinal direction 22.

[0277] The design of the injection mold 42 according to Figure 20This enables short cycle times for the production of interdental brushes 10. Since each first tool part 44 assumes four different positions, in each of which different actions can be performed, as is the case in connection with the Figure 21 as explained below.

[0278] In a first position A, the bristle field cavity 50 is closed by moving the bristle field tool parts 48 into the closed state. Next, the neck tool parts 56 are moved towards each other into the closed position and moved longitudinally 22 in contact with the bristle field tool parts 48. The clamping punches 64 and the fixing element 64' are held spaced apart from each other in a rest position, outside the neck cavity 58.

[0279] Then this first tool part 44 - at the in the Figure 20In the illustrated embodiment, the support core 24 is moved into a second position B by rotating it 90° about the axis of rotation 124. In this second position B, the support core 24 is inserted longitudinally 22 through the neck cavity 58 and then through the bristle field cavity opening 54 into the closed bristle field cavity 50, after which the clamping plungers 64 are brought towards each other and the fixing element 64' is moved into the clamping position.

[0280] The core 24 can be fed into the process as a part already in the correct length (e.g., a cut part) or as a continuous part. In the latter case, it is necessary to cut the core 24 to the correct length during the process. Furthermore, it is also possible to mold the core 24 from a plastic material, for example, in a separate or integrated injection molding process, thus enabling the interdental brush to be manufactured entirely from plastic.

[0281] Then, the first tool part 44, with the inserted and held support core 24, is moved, again by rotation, into a third position C, in which the first tool part 44 is located at the second tool part 46. The grip cavity 68 is closed by moving the grip tool parts 66 towards each other. Furthermore, the first tool part 44 and the second tool part 46 are moved towards each other and brought into a position abutting one another, so that the grip cavity 68, together with the neck cavity 58 and the bristle field cavity 50, including the cap cavity 82, forms the injection cavity 72.

[0282] Then the plastic is injected into the handle cavity 68, forming the handle 16' in the handle cavity 68, the neck mantle 32 in the neck cavity 58, the sheathing 28 in the bristle field cavity 58, as well as the bristles 20 and the extension 30 in the cap cavity 82.

[0283] Once the plastic has hardened sufficiently to be dimensionally stable, the handle cavity 68 is opened by moving the handle tool parts 66 away from each other. This demolds the handle 16'. Next, the first tool part 44 and the second tool part 46 are moved away from each other. Finally, the first tool part 44 is rotated into a fourth position D.

[0284] In this position D, it is possible to injection-mold a second component, for example made of a hard or soft material, onto the already manufactured handle 16'. If desired, a third tool part of the injection mold 42 is located at this fourth position D. This third part can be designed identically to the second tool part 46, except that only the cavities next to the holder for the already manufactured handle 16' are designed for injection-molding the additional component.

[0285] The already manufactured handle 16' projects beyond the neck tool parts 56 and enters the relevant cavity in the fourth position D. The tool parts are brought together, the cavity is closed, and then the second component is injected. After at least partial curing of this component, the further handle cavity is opened, and then the first tool part 44 is returned to the first position, position A. In this position, the bristle field tool parts 48 are moved into the open state, thus exposing the bristle field section 12 and the handle section 16 of the interdental brush 10.

[0286] By moving the neck tool parts 56, which are in the closed position, longitudinally 22 away from the bristle field tool parts 48, the interdental brush 10 is removed from the bristle field cavity 50. Subsequently, the neck tool parts 56 and the clamping punches 64 or the fixing elements 64' are moved away from each other, and the clamping punches 64 are returned to their rest position before, simultaneously with, or after this movement. The interdental brushes 10 are now free and can be removed from the injection mold 42, for example, by means of a gripper (e.g., on a robot).

[0287] Depending on the design, the gripper holds the interdental brushes 10 as soon as the neck tool parts 56 and the clamping die 64 open. Another design option, depending on the design of the injection mold, is to simply drop the manufactured parts.

[0288] Subsequently, the first tool part 44, or its parts, are closed again as described initially, and a new manufacturing cycle can begin.

[0289] The one in Figure 20 The illustrated embodiment with four first tool parts 44 thus has the advantage of a large production capacity, whereby while the first component of an interdental brush 10 is being injected, actions are being carried out in the other positions.

[0290] If it is not intended that a second component is injected onto handle 16', the fourth position D can be omitted, as shown in the Figure 21 as shown by a dashed line 126. In this case, the injection mold 42 advantageously has three first mold parts 44, which are preferably rotated by 120° each around the axis of rotation 124 from position to position.

[0291] In this case, it is also possible, for example, to divide the activities from one position to several positions. For instance, at position A, opening and product removal can be grouped together and separated from closing and assembling the tool parts.

[0292] Furthermore, it is conceivable, as in Figure 21 as indicated by the dashed line 126', to insert the support core 24 into the closed bristle field cavity 50 in the first position A.

[0293] In this case, it is advantageous – if no second component needs to be injection-molded onto the handle 16' – to provide two first tool parts 44, each of which is rotated 180° about the axis of rotation 124 into the corresponding positions (A, C). However, if injection of a second component is required, the injection mold 42 preferably has three first tool parts 44.

[0294] Preferably, the first tool parts 44 are arranged in the manner of the blades of a helicopter rotor, evenly distributed in the circumferential direction to the axis of rotation 124 and attached to a central rotating part.

[0295] Possible further processing of the interdental brushes 10 produced as described above will be discussed in connection with Figure 22 received.

[0296] In Figure 22 This section demonstrates how the injection molding process and subsequent manufacturing steps are integrated into the overall production process when an inline solution is used, meaning the manufacturing steps are directly linked. The advantages of this manufacturing method are obvious. For example, they are more economical, no intermediate storage is required, and damage to the bristle field is virtually eliminated.

[0297] For example, it is possible to process the injection-molded interdental brushes 10 in several steps and then package them directly. Furthermore, it is possible to incorporate buffering between the several processing steps. This buffering serves to absorb fluctuations in output between the preceding and subsequent process steps.

[0298] Thus, it is possible that the injection-molded interdental brushes 10 can be further processed after injection molding, for example, by embossing or printing. Post-processing can also affect the bristle field; for instance, the bristle support stem 18 of the interdental brush 10 can be curved. Treating the bristle field 26 with substances such as dental solutions, toothpastes, or disinfectants is also possible. Applying heat to the bristle field 26 is also possible, as is twisting the bristle field 26 to give it a torsional shape.

[0299] The aforementioned processing operations are possible before or after buffering or directly before packaging the interdental brushes 10.

[0300] Further processing is also possible inline before the interdental brushes are packaged.

[0301] It is also conceivable to process the manufactured interdental brushes offline. The individual steps can be completely separate and take place independently of each other. It is possible for each intermediate product to be stored before further processing.

[0302] Besides the option described above, where the product is manufactured entirely in the injection molding tool and is a "stand-alone" product, it is also possible to produce only a part of the product. Instead of the complete 16' handle, an interface geometry can be designed that fits onto a similarly shaped part of a handle. The brush part is replaceable and is either clicked into the handle or attached in another way that allows for easy removal.

[0303] Alternatively, it is also possible to design the interdental brush to be as identical as possible to an existing twisted brush, for example, by injection-molded a plastic handle. This allows existing twisted brushes without a handle to be replaced directly. This is used, for example, in handles into which simple twisted brushes can be inserted, where the brushes are held / clamped by bending the extension of the bristle support shaft.

[0304] It is also possible to use the co-injection process for manufacturing the aforementioned interdental brushes. This would mean that two components are injected into the first cavity of the injection mold. Specifically, a first component is injected, but it does not completely fill the cavity. After partial hardening, a second material component is injected through the same injection point. This second component either displaces the existing component and occupies that space within the existing component, or it penetrates the existing component. In this way, it is possible to produce a two-component part in a single injection mold cavity. For example, the handle and bristles can be different colors, or different materials can be used for the handle and bristles.

[0305] In the Figures 23 to 29A variant of an interdental brush 10 is shown, in which the support core 24 is also made of a plastic using injection molding.

[0306] The interdental brush 10 shown has a bristle field section 12 with a bristle field 26, a neck section 14 with a neck element 32, and a handle section 16 with a handle 16'. A bristle support stem 18, from which the bristles 20 extend, also extends in a straight line over the entire length of the bristle field section 12 in this variant and defines a longitudinal direction 22; the dashed line indicating the longitudinal direction 22 in turn defines the longitudinal axis.

[0307] In this case, the handle 16', the neck element 32, and the support core 24 are integrally injection-molded from a single plastic. The support core 24, which adjoins the neck element 32 on the side facing away from the handle 16', has a smaller diameter than the neck element 32; preferably, the support core 24 tapers with increasing distance from the neck 32. A casing 28 is injection-molded around the support core 24, which, with a cap-like extension 30, encloses the free end of the support core 24 facing away from the neck section 14.

[0308] The handle 16' has a flattened shape for optimal handling. This flattened shape can be in the form of a plate, which may have recessed indentations on its upper and / or lower surface to accommodate fingertips (not shown). These recessed indentations may also contain nubs to further enhance grip. The bristles 20 and the bristle field 26 are injection-molded together with the sheath 28. The sheath 28 and the bristle field 26 are preferably injection-molded from a different plastic material than the handle 16', the neck element 32, and the core 24. The handle 16' may also be provided with an additional plastic component, particularly a soft component, for improved ergonomics and functionality.

[0309] In this case, the bristle field 26 consists of bristles 20 that extend from essentially three sides (or three lateral sections) of the interdental brush 10. One side (or one lateral section) remains bristle-free in this variant. As can be seen, the bristles 20 do not extend radially from the longitudinal axis 22 of the support core 24; rather, the individual rows of bristles 34 running in the longitudinal direction 22 are each arranged at least approximately parallel or at a 90° angle to one another. As, for example, in Figure 27As can be seen, the upper three, approximately parallel, rows of bristles 34 follow the tapering of the supporting core 24 or the sheath 28 (which regularly has a constant thickness and therefore also runs around the supporting core 24 with a corresponding taper) and converge somewhat to a point, while the lateral rows of bristles extend perpendicularly from the supporting core 24 and lie in a common plane. Of course, other angular configurations between the rows of bristles 34 are also conceivable in this variant.

[0310] In Figure 29 is one of the Figures 23-28 An alternative cross-section in the area between the bristle rows is shown. In this view, the supporting core 24 emerges from the sheathing in the area of ​​the bristle field section 12 and thus forms at least part of the actual back side of the bristle field 26. The supporting core 24 is therefore partially surrounded by a sheathing or layer 28, with the exception of the lower side.

[0311] The supporting core 24 is preferably designed in the form of a rounded trapezoid. However, the supporting core can also be triangular and be completely enclosed by the casing 28 on two sides and not at all or only partially enclosed on one side. The supporting core can also have a round cross-section.

[0312] The supporting core 24 can therefore also form a three-dimensional geometry which differs from the previous embodiments, since it is formed together with the handle 16' of the interdental brush 10.

[0313] The manufacture of an interdental brush 10 according to the Figures 23 to 29This embodiment is somewhat simpler than those of the previous embodiments. The support core 24 can, for example, be produced in a cavity of an injection mold in which the bristle field is later also produced using a two- or multi-component injection molding process. As in the previous embodiments, the support core 24 is inserted longitudinally 22 through the bristle field cavity opening 54 into the closed bristle field cavity 50. Alternatively, it is also possible to produce the support core 24 in a separate injection mold and then feed it into the injection mold in which the bristle field is formed, and insert it accordingly into the injection mold cavity.

[0314] The support body 24 is preferably fixed in the injection mold in the area of ​​the handle 16', at points where only a plastic component is present (i.e., not at points where, for example, a soft component is also present). Depending on the design, the fixing can be achieved solely by means of the walls of the injection molding cavity – without the need for separate clamping dies. The fixing element is then formed by the cavity wall. The injection point 51 of the plastic component, which forms the covering 28 as well as the bristles 20, is preferably located at the front end of the handle 16'. In this way, the plastic component of the covering 28 covers a small part of the surface on the handle 16', while on the back of the interdental brush 10, it covers a substantial part of the surface of one side at the neck element 14, before finally completely covering the surface in the bristle field section 26 (see Figure 1). Figure 25 ).

[0315] Furthermore, it is possible to combine the injection-molded bristles 20 with twisted bristles, so that, for example, twisted bristles are present in the front part of the interdental brush 10. For this purpose, a twisted brush is produced in a first step, which has twisted bristles at its front end and is equipped with twisted wire at its rear. This part is placed in the injection molding cavity, clamped, and also clamped in front of the area with the twisted bristles. Subsequently, the twisted wire is overmolded and fitted with injection-molded bristles 20.

[0316] The in the Figures 30-31 The illustrated product group 200 according to the invention comprises several brushes of the type described in the Figs. 23-29The embodiments of the invention are shown. Preferably, a product group consists of five brushes, as shown. As can be seen, the adjacent brushes are connected to each other in the area of ​​their handles 16' by means of two material bridges 128.

[0317] Depending on the design of the handle 16', the material bridges 128 are of the same or different lengths. They can each also have a predetermined breaking point S, for example in the form of a perforation or a notch or material weakening, at which the individual brushes can be easily and cleanly separated from one another.

[0318] According to the invention, the injection point 51" of the second component is located at the front end of the handle 16', facing the neck element 32. In other words, the second plastic component is injection-molded onto the front end of the handle 16', facing the neck element 32, with the second plastic component covering a small part of the surface on the handle 16', while on the rear side of the neck element 32 it covers a substantial part of the surface and completely covers the surface of the supporting core 24, or at least with the exception of a lower side (see Figure 1). Fig. 29 ), covered.

[0319] The second plastic component is injected into the product at a separate injection point 51" for each interdental brush 10. The first plastic component is injected via the injection point 51'. It is possible that there is only one injection point 51' for the first component for a product group, or that there are several injection points 51'. The injection points are preferably arranged regularly or symmetrically with respect to their placement on the products of the product group. Furthermore, the injection point 51' or 51" is always located in the same position within each individual product. Preferably, no more than one injection point per product is ever used for each plastic component.

[0320] The other parts / components correspond to those described in the Figs. 23-29 The components shown are shown. A hot runner system is typically used for this embodiment. The use of a cold runner system is also conceivable.

[0321] In the Figures 32-34 A brush or interdental brush 10 is shown, which in turn has a handle 16' from which the neck element 32 and the core (here concealed by the layer / covering 28) extend. As can be seen, three converging rows of bristles 34 (the middle one of which runs along the longitudinal axis 22) are arranged on the upper side of the bristle stem 18, which, together with the two rows of bristles 34 projecting essentially horizontally from the core (or bristle stem 18), define the bristle field 26.

[0322] The bristles 20 decrease in length towards the end of the bristle stem 18 furthest from the neck element 32. This is particularly evident in... Fig. 34 The two rows of bristles 34, which are arranged in a plane below the longitudinal axis 22 of the supporting core 24, can be seen.

[0323] Due to the fact that the core and the bristle stem 18 taper towards their ends furthest from the neck element 32, the plane in which the essentially horizontally arranged bristle rows lie may not be entirely parallel to the longitudinal axis 22. The handle 16' of the brush is flat. The cap-like extension 30 of the layer / coating 28 encloses the free end of the core furthest from the neck element 32. The injection point 51" for the second plastic component is located either at the free end of the core or at the end of the core furthest from the neck element 32 (i.e., in the bristle field cavity opening). No second plastic component is applied to the handle 16' or the neck element 32 of the individual brushes. In this embodiment, a cold runner system is typically used. The injection point 51" is preferably located at the free end of the core.

[0324] The in the Figures 35 and 36 The product group 200' shown accordingly has only one material bridge 128 between the handles 16' of the adjacent brushes or interdental brushes 10. These material bridges 128 are also formed from the first plastic component and can have a predetermined breaking point S in the form of a perforation, a notch, or a material weakening.

[0325] Accordingly, no second plastic component is applied to the handle 16' and the neck element 32 of the individual brushes. In the frontal view according to Figure 37 The connection of the brushes of product group 200' via the individual material bridges 128 between the handles 16' and the geometry of the bristle field 26 described above can be seen again. The supporting core 24 has a trapezoidal cross-section. Preferably, each product group 200' consists of five brushes.

[0326] During the Figures 38-40In the illustrated brush, two rows of bristles 34 are arranged on the upper side of the support core 24 or bristle stem 18, which converge towards the end of the bristle stem 18 facing away from the neck element 32 (which, like the support core, tapers in this direction) and which, as shown in Figure 41 The bristles are illustrated as projecting outwards (i.e., not essentially vertically but also not radially) from the top of the supporting core 24. Furthermore, two rows of bristles 34 are provided, projecting essentially horizontally from the supporting core 24 or from the bristle stem 18.

[0327] The cap-like extension 30 of the layer / covering 28 also encloses the free end of the supporting core or bristle stem 18 facing away from the neck element 32. In this brush, the second plastic component is injection-molded onto the rear end of the handle 16' facing away from the neck element 32, with the second plastic component covering a large part of the surface of the handle 16' both front and back, while on the back it is located on the neck element 32 (cf. Figure 39 ) covers a substantial part of the surface and completely covers the surface of the supporting core 24.

[0328] However, there is also the possibility that, analogously to Figure 29 The lower side of the support core is not covered with the second plastic component. The handle 16' of the brush has a concave indentation 17 on both the front and back for improved grip, as shown in Fig. 40 to be seen. On the back of the handle 16' (cf. Figure 39 The second material component is guided in an elongated indentation 19 of the neck element 32. Since the injection point 51" is located at the rear end of the handle 16', the second plastic component flows from there through the trough-shaped indentation of the handle 17 and the elongated indentation 19 of the neck element 32 to the supporting core, where it finally forms (in the corresponding bristle field cavity) the layer or coating 28 with the bristles 20. Figure 38 The support points 130 can be identified at which the support elements 74 of the bristle field cavity 50 are attached (cf. analogous). Figure 13 ) and prevent the support core 24 from moving radially and potentially closing the openings for the individual bristles 20 to be formed. A hot runner system is generally used for this variant to prevent the second plastic component from solidifying prematurely on its relatively long flow path.

[0329] A product group of 200" with brushes, which are located in the Figures 38-41 The brushes shown are very similar, and this is explained in the text. Figures 42-43 illustrated. Only the shape of the handles 16' deviates from the oval handle shape according to the Figures 38-40 away.

[0330] The handle shape of the brushes is essentially rectangular and has a lateral indentation 131 on each side. This is because the individual brushes of product group 200" are connected via two material bridges 128, 128', wherein the material bridges 128 are formed from the first plastic component and the material bridges 128' from the second plastic component.

[0331] The material bridges 128 made from the first plastic component are each arranged in the rear region of the handle 16', and the material bridges 128' made from the second plastic component are each arranged in the front region of the handle 16'. With this design, it is not necessary to have a injection point for the second plastic component on every brush.

[0332] The handles 16' (including the neck element and support core), initially injection-molded from the first plastic component, are positioned close together. Furthermore, the handles 16' have transitions 132 on the top and back surfaces in the area of ​​the second material bridge 128' (to be injection-molded later), allowing the second plastic component to be applied. Therefore, a separate injection point for the second plastic component is not required on each product or brush. Preferably, this product group 200" also consists of five brushes each.

[0333] In the Figures 44-46Finally, another variant of an interdental brush is shown, which has a notch 134 at the rear end of the handle 16' for attaching the brush to a corresponding holder 140, or for example a cup or a glass. In the schematically depicted exemplary embodiment, this is an interdental brush with an overmolded wire or support core 24, which projects from the neck element 32 and carries a bristle field 26.

[0334] The material of the at least one plastic component for the handle 16' and the neck element 32 can be selected such that the two lateral flanks 136 (or clamping arms) of the handle 16' surrounding the indentation 134 are resiliently designed and can thus be attached to the holder 140, the glass, the cup, or the like in a form-fit and force-fit manner. The handle 16', or the handle 16' and the neck element 32, can also be injection-molded from two (or more) different plastic components. In the preferred embodiment, the indentation 134 is overmolded with a rim 135 made of a second or further plastic component, which is typically a soft component. This further improves the grip of the brush on the respective holder 140. In this embodiment, the rim 135 is H-shaped, which can be advantageous for handling.The lower ends of the lateral flanks 136 are preferably completely surrounded by the soft component. As shown in the side view according to . Figure 45 As can be seen, the lateral flanks taper towards their lower end (136).

[0335] Such a notch 134 and rim 135 can of course also be used in an interdental brush with a plastic injection-molded core, as is the case in the Figures 23-43 This will be illustrated (as well as in the relevant product groups).

[0336] The injection point for the first plastic component 51' is located, in the embodiments according to the Figures 23 to 46 Preferably located in the handle area. Depending on the design, one or more injection points per product or product group are conceivable. Preferably, one injection point will be provided, with the plastic material distributed within the individual product and across the material bridges.

[0337] The respective brushes according to the Figures 23 to 46 These parts can each be injected in the parting line of a two-part injection mold and easily demolded, enabling particularly cost-effective and efficient production. The injection mold for these designs also typically does not require neck mold components or clamping dies.

[0338] Naturally, the embodiments shown in this document are exemplary. Within the scope of the present invention, some individual features and elements of these embodiments can readily be combined with other embodiments.

[0339] The descriptions given for specific characters can of course also be applied to other characters that show the same or similar characteristics, even if these characteristics are not described in the same level of detail.

Claims

1. Interdental brush comprising a bristle-carrying stem (18) defining a longitudinal direction (22) with an elongated supporting core (24), a bristle field (26) with bristles (20) projecting from the bristle-carrying stem (18), and a neck element (32) connecting the supporting core (24) to a handle (16'), wherein the handle (16'), the support core (24) and the neck element (32) are integrally molded from a first plastic component made of hard material, and wherein a second plastic component made of soft material is applied to the support core (24) in the form of an integral layer (28) with bristles (20) projecting therefrom, wherein the integral layer (28) made of soft material is preferably applied flush with the neck element (32) to the support core (24), and characterized in that the injection point (51, 51") of the second plastic component is located at the front end of the handle (16') facing the neck element (32).

2. Interdental brush according to claim 1, wherein the neck element (32) is partially encased by the second plastic component.

3. Interdental brush according to claim 1 or 2, wherein the second plastic component covers a small part of the surface on the handle (16'), wherein the second plastic component covers a substantial part of the surface on a rear side of the neck element (32), and wherein the second plastic component covers the surface of the support core (24) completely or with the exception of a lower side.

4. Interdental brush according to any one of the preceding claims, wherein the second plastic component is received in recesses (17) or a hole in the handle (16'), where it forms a section with increased grip.

5. Interdental brush according to any one of the preceding claims, wherein the neck element (32) has channels which enable or at least support the flow of the second plastic component.

6. Interdental brush according to any one of the preceding claims, wherein the support core (24) has a plurality of support points (130) spaced apart from each other in the longitudinal direction, which are preferably free of material of the second plastic component.

7. Interdental brush according to claim 6, wherein the support core (24) has a smaller diameter than the neck element (32), wherein the support core (24) tapers toward its end facing away from the neck element (32).

8. Interdental brush according to any one of the preceding claims, wherein the integral layer (28) is designed such that it forms a sheath (28) around the support core (24) in the area of the bristle stem (18), wherein the sheath (28) preferably covers the free end of the support core (24) like a cap.

9. Interdental brush according to claim 8, wherein the thickness of the sheath (28), measured outside the area of the bristles (20) and in the radial direction with respect to the longitudinal direction, is between 0.05 mm and 0.3 mm, preferably between 0.1 mm and 0.2 mm.

10. Interdental brush according to any one of the preceding claims, wherein it has a length of 35 mm to 70 mm, preferably 40 mm to 55 mm, and preferably a height including the bristle field of 0.8 mm to 2.8 mm, preferably from 1 mm to 2 mm, and preferably a width of 3 mm to 12 mm, preferably from 5 mm to 8 mm.

11. Interdental brush according to any one of the preceding claims, wherein the ratio of the bristle diameter to the diameter of the support core (24) is from 1:8 to 3:1, preferably from 1:2 to 3:4.

12. Interdental brush according to any one of the preceding claims, wherein the ratio of the bristle diameter to the diameter of the bristle support stem (18) is from 1:30 to 3:2, preferably from 1:6 to 1:3.

13. Interdental brush according to any one of the preceding claims, wherein the bristles (20) protrude at least approximately radially from the bristle-carrying stem (18) and are arranged in rows of bristles (34) extending in the longitudinal direction (22), wherein the rows of bristles (34) are preferably distributed evenly in the circumferential direction, wherein the bristles (20) are preferably arranged in bristle planes (36) extending at right angles to the longitudinal direction (22) and wherein preferably the bristle planes (36) have a constant spacing in the longitudinal direction.

14. Interdental brush according to any one of the preceding claims, wherein the interdental brush is combined with a flosser, a toothpick, or a tongue cleaner.