INTERDENTALBÜRSTE

Description

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

[0002] US Pat. No. 3,698,405 discloses toothpicks with a plastic or metal rod, with a rubber sponge sheath attached to the rod along its entire length. Stubs may protrude from the surface of the rubber sponge. The rubber sponge should contain at least 70% air. In another embodiment, the rubber or rubber sponge is attached to the rod 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, which is covered in partial areas of its surface by at least one insert or overlay 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 with it. If the first plastic material of the carrier and / or the second plastic material of the insert or overlay contains one or more additives, the cleaning and care effect can be varied and optimized. To produce such an interdental cleaner, the second plastic material of the insert or overlay is sprayed onto the first plastic material of the carrier, whereby the carrier and the insert or overlay can be manufactured using a two-component injection molding process.

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

[0005] Furthermore, document WO 2008 / 146968 A discloses a method and a tool for producing a mascara brush. The tool has an upper mold box and a lower mold box, which together, when closed, form cavities for producing the application heads by casting. For each mascara brush, a wick made of ceramic or plastic is inserted into the lower mold box, and after the upper and lower mold boxes are brought together, a soft material is injected into the cavities. For this purpose, the tool has a compression plate that interacts with the upper mold box, with feed passages leading from the space formed by the compression plate and the upper mold box through the upper mold box into the cavities. Material that is liquefied under pressure is inserted between the compression 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 pressed through the connecting openings into the cavities.

[0006] Document US2011041271A1 discloses an interdental brush comprising a bristle support stem defining a longitudinal direction with an elongated support core, a bristle field with bristles projecting from the bristle support stem, and a neck element connecting the support core to a handle, wherein the handle, the support core, and the neck element are integrally injection-molded from a first plastic component made of hard material, and wherein a second plastic component made of soft material is injection-molded onto the support core in the form of an integral layer with bristles projecting therefrom, wherein the handle and the neck element have recesses, and wherein the integral layer of soft material is injection-molded onto the support core flush with the neck element. T

[0007] The description discloses a particularly simple injection molding process for producing 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 produced brush, in particular an interdental brush, and a product group comprising a plurality of brushes.

[0008] In addition to interdental brushes, the brushes can be, in particular, mascara brushes, medicinal brushes, cosmetic brushes, body care brushes, cleaning brushes, household brushes, etc. This object is achieved by a method according to claim 31, a brush according to claim 1, and a product group according to claim 28 or claim 29.

[0009] Particularly preferred embodiments are specified in the dependent claims.

[0010] The description includes a method for producing a brush, in particular an interdental brush, which has a bristle support stem defining a longitudinal direction with an elongated support core, a bristle field with bristles projecting from the bristle support stem, and a neck element connecting the support core to a handle, comprising the following steps: injection-molding the handle, the neck element, and the support core integrally from a first plastic component, inserting the support core in the longitudinal direction through a bristle field cavity opening of an injection mold into a bristle field cavity, fixing the support core inserted into the bristle field cavity to prevent movement of the support core in the longitudinal direction, and applying a second plastic component from an injection point of the injection mold onto the support core for integrally forming a layer on the support core and the bristles projecting from it; and a brush, in particular an interdental brush,comprising a bristle support stem defining a longitudinal direction with an elongated support core, a bristle field with bristles protruding from the bristle support stem, and a neck element connecting the support core to a handle, wherein the handle, the support core, and the neck element are integrally injection-molded from a first plastic component, and wherein a second plastic component in the form of an integral layer and the bristles protruding from it are applied to the support core. The description also includes a product group comprising a plurality of 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, as well as a product group comprising a plurality of 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.,

[0011] A product group consists of three to eight products arranged in a row, preferably five to six. For simplicity, the figures are shown with only five products each.

[0012] The description further includes a method for producing a brush, in particular an interdental brush, which has a bristle support stem defining a longitudinal direction with an elongated support core, a bristle field with bristles projecting from the bristle support stem and a neck element connecting the support core to a handle, with the following steps: injection molding the handle, the neck element and the support core integrally from a first plastic component in a first injection molding cavity, folding the injected part into a further cavity of an injection molding tool with bristle cavities, fixing the part introduced into the bristle field cavity to prevent movement of the support core in the longitudinal direction, and applying a second plastic component from an injection point of the injection molding tool to the support core for the integral formation of a layer on the support core and the bristles projecting from this.

[0013] The transfer in the injection molding tool preferably takes place with a transport bar, which moves the at least partially manufactured products after a lifting movement from the cavity by a translational displacement or a rotation to another cavity, where they are placed in the cavity by means of a stroke.

[0014] The transport bar is preferably part of the cavity, meaning that the transport bar forms part of the molding geometry, at least during 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 of both.

[0015] The often desired customization of the product can be achieved, for example, through interchangeable shaping parts in the handle or neck. This allows lettering or other surface geometries to be formed. These elements can be arranged both in the transport bar and in the actual cavity.

[0016] After injection molding, the manufacturing process for these products is completed to the extent that usable products are produced. Accordingly, the product can be packaged after injection molding.

[0017] The products are preferably packaged in a box that is presented to the end consumer. The products are arranged horizontally or vertically, directly adjacent to one another.

[0018] The packaging process can be integrated inline, meaning linked, or offline in a separate step. In the inline process, injection molding and packaging are linked. The products are not removed from the machine until they are completely packaged. In the offline process, storage, transport, etc., takes place after injection molding before packaging.

[0019] It is also 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.).

[0020] A hard plastic is preferably used as the first plastic component, from which the handle, the support core, and the holding element are usually integrally formed, and a soft component is preferably used for the second plastic component, from which the layer or the bristles protruding from it are formed. It is of course also possible to use a further, third component, for example, in the area of ​​the handle to increase grip and improve ergonomics, or in the area of ​​the bristle field in the form of additional cleaning elements or other functional elements. Examples of the materials considered in this context are listed further below in the general description.

[0021] With regard to 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. In general, several products are preferably arranged next to one another and the products are connected via material bridges in the handle area. The longitudinal axes of the brushes are preferably arranged parallel. As a rule, one, two or three material bridges are provided (although more are conceivable). These primarily give the product groups stability. The products are also separated at the material bridges for use. Since separating the individual brushes can create edges that could injure delicate tissue such as the oral mucosa, the material bridges are arranged regularly in the handle. The material bridges are preferably each made from the same component.It is also possible to use two different components or several different components, one for each material bridge. However, this depends on the injection points selected, with preferably only one injection point for each component per product group. More preferably, one material bridge is arranged towards the front and the other towards the rear of the handle to ensure sufficient distance between the material bridges. The material bridges can be rectangular or oval in cross-section, the cross-section preferably has a longer and a shorter length and the longer length of the cross-section preferably lies in the direction of the longitudinal axis of the product. The material bridges can also comprise elements to assist the separation process, such as notches or perforations as predetermined breaking points.With regard to 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, different lengths of the cleaning tips, and different overall lengths of the brushes can be provided. Regarding the material, a variation can be made in the second component (i.e., the soft component).

[0022] In a preferred embodiment of the description, the second plastic component surrounds the preferably bristle-free neck element at most partially.

[0023] This depends on the choice of injection points, but designs are also conceivable in which the neck element is completely encased by the second component.

[0024] In a further preferred embodiment of the description, the support 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.

[0025] In this way, the manufacturing process can be made more efficient than if a completely different injection molding tool had to be used.

[0026] In yet another preferred embodiment of the description, the layer is formed in such a way that it forms a sheath of the supporting core in the region of the bristle stem.

[0027] Such a sheathing allows for a particularly good and secure fit on the supporting core. In particular, the second component can be selected with regard to its shrinkage behavior so that it shrinks onto the supporting core.

[0028] 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 in the direction towards the interior of the bristle field cavity, at a plurality of support points spaced apart from one another in the longitudinal direction.

[0029] The support points are preferably arranged between the bristles. This effectively prevents the support core from moving in the radial direction (i.e., away from the longitudinal axis) and potentially closing the openings for the bristles to be formed.

[0030] In yet another preferred embodiment of the description, the fixing of the support core in the region of the handle preferably takes place at locations where only one plastic component is present.

[0031] This is intended to prevent a second, possibly softer plastic component from being damaged by the fixing agents.

[0032] In a further 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.

[0033] The selected material combinations depend on the specific application, and the materials used are specified further below in the general description. For the hard-semi-hard combination, for example, a PE-PE material pairing is suitable, with HDPE being used for the first material component and LLDPE for the second. For the hard-soft combination, a PP-TPE material pairing is suitable.

[0034] The materials used can be water-soluble and edible and can be made, for example, entirely or partially from hydrocoloids, starch, gum arabic, polyvinyl alcohol, polyox.

[0035] It is also possible to spray on a material as an additional component or to dip the existing product in a bath to apply another component, for example, as a coating. Substances that can be used as coatings or as ingredients for the above-mentioned materials include color, flavor, dental cleaning fluid, toothpaste, and active ingredients.

[0036] Further preferably, the support core has a smaller diameter than the neck element.

[0037] This ensures that the supporting core does not become too thick at its front end for use in the interdental area.

[0038] Preferably, the layer is sprayed or applied onto the supporting core flush with the neck element.

[0039] The flush finish of the layer with the neck element is more comfortable to handle and offers a more visually advantageous design.

[0040] In another preferred embodiment of the present invention, the injection point of the second plastic component is located at the front end of the handle facing the neck element.

[0041] The choice of injection point is fundamentally 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 sprue system is not thermally insulated from the rest of the mold. Thus, both the mold and the sprue system within it are kept at temperatures significantly below the processing temperatures of the plastic. This causes the thermoplastic to solidify in the sprue system during the production of a component.

[0042] In a hot runner system, the sprue system is thermally separated from the rest of the mold and heated separately, so that the plastic melt in the sprue system remains permanently flowable. This prevents the plastic from solidifying in the sprue system, and no sprue remains on the part. Furthermore, hot runner systems also allow for longer flow paths because the pressure loss in the sprue system is not increased by the cooling of the melt and the associated increase in viscosity.

[0043] Due to the above-mentioned choice of injection point, the plastic component of the casing covers a small part of the surface on the handle, while on the back of the interdental brush it covers a substantial part of the surface on one side of the neck element before finally completely covering the surface in the bristle field section. According to the invention, the parts injection-molded from the first plastic component (handle, neck element and support core) have corresponding depressions or channels which enable or support the flow of the second plastic component. Correspondingly, opposing injection molding tools are used in each case. In this embodiment, the injection nozzle is arranged in the handle cavity and, due to the flow path, a hot runner system is preferably used.

[0044] In yet another preferred embodiment of the present invention, 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.

[0045] If the injection point is located at the free end of the support core, a separate injection point will be provided for each brush. A cold runner system is typically used in this case, with additional means provided in the mold or during post-processing to separate the product from the sprue. Punches or cutters are generally considered as release agents. The injection nozzles are thus each located in the bristle field cavity, and either a tunnel sprue, a film sprue, or other common sprue types can be used.

[0046] In yet another preferred embodiment of the present invention, the injection point of the second plastic component is located at the rear end of the handle, facing away from the neck element.

[0047] 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 portion of the surface of one side of the interdental brush at the neck element, before completely covering the surface in the bristle area.

[0048] The second plastic component is held in corresponding recesses or a hole in the handle, where it forms a section with increased grip.

[0049] A corresponding recess in the handle can be provided with a structure, such as a structure on the edge or bottom of the recess. The shape of the structure can include knobs, grooves, slats, or similar features, as well as combinations thereof. One or more components can protrude through one another; for example, hard components can protrude through soft components.

[0050] The trough can be designed with a two-component or three-component coating to further improve grip and ergonomics.

[0051] Furthermore, transitions can be provided, in the form of soft transitions from the handle, or hard transitions from the handle, such as with a stepped recess.

[0052] In principle, closed or open troughs can be provided. In the closed version, the edge is continuous throughout the trough, while in the open version, the trough is open on at least one side (for example, guides on the left and right along the longitudinal axis). It is also conceivable for the trough to be open at the front and back.

[0053] With regard to designs with a hole in the handle, various configurations are also conceivable. There may 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 (e.g., with rounded corners) are also conceivable.

[0054] Furthermore, combinations of troughs and holes are also possible, such as holes within a trough.

[0055] Further preferably, the support core has a round, triangular or trapezoidal cross-section.

[0056] The cross-sectional shape of the support core generally depends on the specifically selected bristle field geometry. Furthermore, the support core may be completely or only partially surrounded by the sheath or layer on one side (usually the bottom side). In this case, the support core also has no bristles on this side.

[0057] In another preferred embodiment of the present invention, the support core, and preferably also the bristle stem, taper towards their end facing away from the neck element.

[0058] The tapered design of the supporting core and preferably also of the bristle stem ensures greater variability of the brush and may contribute to the brush being able to be inserted more easily into the interdental area.

[0059] In a preferred embodiment of the present invention, the handle has a notch at its end facing away from the neck element, which notch is preferably provided with a border made of a soft component.

[0060] The notch allows the brush to be attached to a holder, glass, or cup. The soft-edged rim can increase grip and protect against scratches and damage.

[0061] Preferably, the bristles protrude in a non-radial manner from the longitudinal axis of the supporting core.

[0062] Rather, the individual bristles or rows of bristles extend essentially vertically from the longitudinal axis of the core, or they are arranged horizontally within a plane that runs through the longitudinal axis or below the longitudinal axis. This improves the cleaning effect of the brush in the critical areas between the teeth.

[0063] Furthermore, the bristles preferably decrease in length in the direction of the end of the bristle stem facing away from the neck element.

[0064] This measure also serves to improve the cleaning effect in the interdental spaces, as the brush can adapt better in its shape.

[0065] In another preferred embodiment of the present invention, two rows of bristles protrude substantially horizontally from the support core in a plane below the longitudinal axis of the support core.

[0066] In another preferred embodiment of the present invention, three rows of bristles are arranged on the upper side of the support core, which rows converge in the direction of the end of the bristle stem facing away from the neck element and which preferably protrude substantially vertically from the upper side.

[0067] These two measures create an optimally complementary bristle field geometry that allows the interdental spaces to be cleaned completely and evenly. The non-radial arrangement of the bristle rows enhances the cleaning effect compared to a radial arrangement.

[0068] In a further preferred embodiment of the present invention, the second plastic component is injection-molded onto the front end of the handle facing the neck element, wherein the second plastic component covers a small part of the surface on the handle, while on the back side on the neck element it covers a substantial part of the surface and covers the surface of the support core completely, or with the exception of a lower side.

[0069] In yet another preferred embodiment of the present invention, the second plastic component is injection-molded onto the front end of the support core facing away from the neck element, wherein the second plastic component covers the surface of the support core completely, or with the exception of a lower side.

[0070] In a preferred embodiment of the present invention, two rows of bristles are arranged on the upper side of the support core, which rows 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 outward inclination.

[0071] Here, too, the two rows of bristles converge toward the free end of the core, and the length of the individual bristles decreases toward the free end of the core. This variant is somewhat simpler to manufacture than the variant with three rows of bristles on top of the core. It also results in a slightly different cleaning effect. In principle, however, the number of rows of bristles can be chosen freely, with two to nine being preferred, and three to five being even more preferred.

[0072] The angle between the individual rows of bristles is a maximum of 180°, i.e., the angle between the two furthest apart rows of bristles. In another preferred embodiment, the angle is between 0 and 90°. For the rows arranged in the center (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°.

[0073] This product can be combined with other cleaning or polishing elements, as well as other functional elements such as flossers (also called dental floss bows or dental violins), toothpicks, and tongue cleaners. Lamellar elements made of the second material component can also be arranged on the supporting core.

[0074] The lamellae can be integrated into the bristle field in various shapes. For example, the lamellae can run spirally around the supporting core, or they can be arranged in a plate-like pattern around the supporting core, with multiple lamellae arranged one behind the other in this manner. It is also possible to arrange longitudinal lamellae that extend along the longitudinal axis. Lamellae can generally be straight or wave-shaped, and their contours can be closed or open. Furthermore, the lamellae can form a height profile.

[0075] The slats can be arranged in combination with the other cleaning elements mentioned, in particular the slats can be arranged between the bristles.

[0076] With regard to the dimensions of the brush according to the invention, 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 to 2.8 mm, and most preferably between 1 and 2 mm. The width of the brush according to the invention is preferably between 3 and 12 mm, and most preferably between 5 and 8 mm.

[0077] In yet another preferred embodiment of the present invention, the second plastic component is injection-molded onto the rear end of the handle 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 on the neck element it covers a substantial part of the surface and covers the surface of the support core completely, or with the exception of a lower side.

[0078] The interdental brush further comprises a handle, a neck element, and a support core. The neck element connects the handle and the support core, and a bristle array is applied to the support core. The handle has a notch at its end facing away from the neck. Preferably, the notch is surrounded by two lateral flanks of the handle, which are further preferably designed to be flexible or resilient in the form of clamping arms. The flexibility of the two clamping arms can be determined by their geometry and / or by the selected plastic materials or material combinations.

[0079] The base body, which in any case comprises 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.

[0080] The notch is preferably surrounded by a soft component border to ensure better grip. However, the notch can also be designed as a membrane with a soft component layer that forms a lip-like shape around the inserted object.

[0081] In addition, the surface in the area of ​​the notch can be designed in such a way that it includes a recess for holding the brush. Furthermore, surface elements such as slats, knobs, or similar can be arranged in the area of ​​the notch to further improve grip.

[0082] In addition to the aforementioned and described application on interdental brushes, the notch functional element can also be used in manual oral care devices in general. For example, it can also be used on other interdental cleaning devices, toothbrushes, flossers, etc.

[0083] In the invention, the interdental brush, which has a bristle support stem defining a longitudinal direction with a support core running in the longitudinal direction and a bristle field with bristles protruding from the bristle support stem, is produced by injection molding.

[0084] For this purpose, a bristle field cavity, which serves to produce the bristle support stem and the bristles, is closed. This is done by moving the mold parts of the injection mold that define the bristle field cavity into the closed state. The thus closed bristle field cavity has a bristle field cavity opening.

[0085] A support core, arranged with its longitudinal extension in the longitudinal direction, is inserted longitudinally through the bristle field cavity opening into the closed bristle cavity. Preferably, a portion of the inserted support core protrudes from the bristle field cavity beyond the bristle field cavity opening.

[0086] The support core introduced into the closed bristle field cavity is fixed in such a way that it cannot move in the longitudinal direction, i.e. it cannot be displaced.

[0087] By subsequently introducing plastic into the bristle field cavity, a layer of plastic is injected onto the supporting core and at the same time the bristles are manufactured integrally with the layer.

[0088] Fixing the support core prevents it from shifting longitudinally as a result of the force exerted on it by the liquid plastic.

[0089] Inserting the support core into the already closed bristle field cavity has the advantage of preventing damage to both the injection mold and the support core when closing the bristle field cavity. Inserting the support core into the open bristle field cavity could, in the case of even minor deformations of the support core, result in the core becoming jammed in the injection mold when closing the bristle field cavity, thus damaging the mold.

[0090] Preferably, an injection molding tool is provided with at least two bristle field tool parts, which, when closed, delimit 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.

[0091] After the bristle field mold parts have been closed, the support core is inserted longitudinally through the bristle field cavity opening into the bristle field cavity and secured using a fixing element. By injecting plastic into the bristle field cavity, the layer and the bristles are formed on the support core at the same time.

[0092] Preferably, the layer is designed as a sheathing of the support core in such a way that the support core cannot come into contact with the teeth when using the interdental brush. This offers the possibility of using a metallic wire, for example, made of spring steel, as the support core, thereby eliminating the risk of galvanic shock.

[0093] Preferably, the plastic is injected in such a way that it flows through the bristle field cavity opening into the bristle field cavity.

[0094] The end of the support core located in the bristle field cavity is particularly preferably completely overmolded with plastic, so that the sheathing forms a kind of cap around the support core at the free end of the bristle support stem.

[0095] In a preferred embodiment, the support core is held longitudinally outside the bristle field to be formed by means of the fixing element, and the plastic is injected such that it flows through the bristle field cavity opening into the bristle field cavity. The support core is thus held upstream 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.

[0096] For this purpose, the bristle field cavity may have a bristle field section and, in the direction of the bristle field cavity opening, a neck section immediately adjacent to this.

[0097] Preferably, the support core is not completely rigidly fixed, but rather the fixation occurs at a section, particularly the end section of the support core, while the unfixed part can move radially within the bristle field cavity. This ensures fixation only axially.

[0098] The bristle field section contains the part of the interdental brush that has the injected bristles and is intended to be inserted into the interdental spaces when using the interdental brush.

[0099] The neck section can thus be made larger than the diameter for the bristle support stem in the bristle field section.

[0100] Preferably, however, the injection molding tool has at least one neck mold part, and the support core is held in the region 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.

[0101] In a further preferred embodiment, the injection molding tool has a cap tool part with a cap cavity, which serves to form the layer, for example the sheathing at the free end of the bristle support stem.

[0102] Preferably, the cap tool part lies directly on the bristle field tool part.

[0103] The first tool part here refers to the cap tool parts together with the bristle field tool parts and, if applicable, the neck tool parts and fixing element.

[0104] Preferably, two neck mold parts, when closed, form a neck cavity, the neck cavity opening of which, during injection of the plastic, is arranged adjacent to the bristle field cavity opening. This enables the simultaneous and integral production of the layer or casing and the bristles together with a neck casing or neck layer around the support core.

[0105] Preferably, the fixing element is formed by two clamping dies, which are diametrically opposed to each other in the longitudinal direction and can be moved toward each other from a rest position into a clamping position to clamp the support core in the clamping position. Preferably, the direction of movement of the clamping dies runs along a common straight line perpendicular to the longitudinal direction. The direction of movement is preferably parallel to the opening direction of the handle cavity and the neck cavity.

[0106] In their clamping position, the clamping dies preferably engage the interior of the neck cavity and are surrounded by plastic during injection molding. The clamping dies preferably seal against the support core so that the plastic cannot flow into the clamping area when it flows around the die pair.

[0107] This results in the plastic component of the interdental brush having recesses created by the clamping stamps, or a passage created thereby, through which the supporting core runs.

[0108] Preferably, the support core is completely enclosed circumferentially by the clamping dies moved into the clamping position, so that a corresponding fixing section of the support core remains free of plastic. The support core thus lies freely in the passage formed in the plastic component—without being encased by the plastic. Preferably, the support core is positioned so deeply in the passage or recess that the risk of galvanic shock upon tooth contact is eliminated, since the teeth cannot touch it.

[0109] In order to achieve a particularly secure fixation of the support core, the clamping stamps preferably have teeth or tooth gaps in the end regions facing each other, which engage with each other in the clamping position.

[0110] Preferably, the support core is centered in the bristle field cavity—in the bristle field section—by means of the bristle field tool parts at several support points spaced apart in the longitudinal direction. For this purpose, the bristle field tool parts preferably have support elements projecting toward the interior of the bristle field cavity.

[0111] Preferably, the support elements protrude between 0.08 mm and 0.16 mm, particularly preferably between 0.1 mm and 0.14 mm, from the lateral surface of the part of the bristle field cavity defining the bristle support stem.

[0112] Furthermore, the support elements are preferably configured with respect to the support core such that, measured in the radial direction, 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 centric or imaginary centric bristle support stem. This allows the support core to be inserted longitudinally into the bristle field cavity and between the support elements without any obstruction or bending occurring. Furthermore, this enables the formation of a thin plastic skin on the support core at the support elements during injection of the plastic.

[0113] Viewed in the longitudinal direction, the support core is supported by the support elements, preferably at an angular offset in succession. The offset is preferably 90°. As a result, the support elements are spaced apart from one another in the longitudinal direction, and no support elements are located opposite one another in the radial direction. The plastic can thus flow virtually unhindered from the bristle field cavity opening through the bristle field cavity, as its cross-section is restricted at a maximum of one point. In this way, the support elements form support points that are spirally formed around the bristle support stem.

[0114] 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.

[0115] The last support point towards the free end of the supporting core is preferably located directly after the last bristle level or directly in front of the last bristle level.

[0116] The support points are preferably arranged regularly. However, it is also possible that the distance between the support points is not always the same in the longitudinal direction.

[0117] The support elements are preferably designed identically across the entire bristle area. Their number is determined by the length of the bristle support stem and the distance between the support points.

[0118] 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 support core and thus the formation of all bristles is ensured

[0119] Bristle holes are understood to be those parts of the bristle field cavity which originate from the surface area determining the bristle support stem and which serve to form the bristles.

[0120] Preferably - not part of the invention - the supporting core is formed by a metal wire, preferably made of a rust-proof or rust-resistant spring steel.

[0121] Steel 1.4310 is most preferred. The yield strength of the metallic wire should be greater than 2000 N / mm2. This ensures a good restoring torque when bending the bristle support stem in the application and prevents the support core from breaking during repeated bending.

[0122] Alternatively, in the description, the supporting core can also be made of plastic, ceramic, or carbon composite fibers.

[0123] Plastic cores can be manufactured by injection molding or extrusion. A reinforced plastic is preferably used to achieve the necessary stiffness and hardness. Glass fibers or glass beads, for example, can be used to reinforce the plastic.

[0124] The injection molding or extrusion process for a plastic support core precedes the injection molding process for the bristle area and can be separate or integrated into the same injection molding tool (two- or multi-component tool). The plastic support core can have a shape different from a wire and define a significant portion of the handle and, if applicable, its surface.

[0125] Preferably, a handle part of the interdental brush is also produced using the plastic during injection molding of the bristle field.

[0126] The handle part is injected into a handle tool part, which is also referred to here as the second tool part.

[0127] For the above-mentioned purpose, the injection molding tool preferably has two handle tool parts, which, in the closed position, form a handle cavity with a front-end handle cavity opening (second tool part). The bristle field tool parts, moved into the closed state, are moved toward the handle tool parts together with the support core inserted into the bristle field cavity and held by the fixing element, in such a way that the front sides of the bristle field tool parts (or neck tool parts) and the handle tool parts abut one another, and the bristle field cavity opening or further neck cavity opening is located at the handle cavity opening.

[0128] The bristle field cavity, if applicable, with the cap cavity, and the handle cavity, if applicable, together with the neck cavity, thus together form an injection cavity for the entire plastic component of the interdental brush.

[0129] This design allows the plastic to be injected into the handle cavity. It then flows through the adjacent handle cavity opening and bristle cavity opening, interposed by the neck cavity or via the neck cavity openings, into the bristle cavity. This eliminates the need for an injection point in the bristle cavity area.

[0130] It is also possible to inject the plastic directly into the bristle field cavity via a corresponding injection point to produce the layer or coating and the bristles.

[0131] In this case, the bristle cavity opening can serve as a closure for the bristle 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 conventional manner.

[0132] Accordingly, it is also possible for the further neck cavity opening to form the end of the injection cavity and for the support core to protrude through this opening so that the protruding section is not overmolded with plastic.

[0133] The brush, in particular an interdental brush, which is manufactured in accordance with the method according to the further embodiment, whether it has a handle or no handle, has a bristle support stem defining the longitudinal direction, with an elongated, longitudinally extending support core and bristles protruding from the bristle support stem. A layer of plastic is injection-molded onto the support core or it is overmolded with the plastic, with the plastic integrally forming the layer or a sheathing of the support core and the bristles.

[0134] Preferably, a fixing section of the support core is at least partially exposed; at the exposed location, the support core is not covered by the plastic. This fixing section is preferably located outside the area where the bristles are located.

[0135] Preferably, the supporting core is partially exposed at support points or is only covered by a plastic film at the support points, which is thin compared to the remaining plastic areas of the sheath. It should be noted that these support points are defined by the support elements described above.

[0136] 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.

[0137] Preferably, the bristles protrude from the bristle stem in a radial direction.

[0138] Further preferably, the bristles are arranged in rows of bristles extending longitudinally and evenly distributed circumferentially. Furthermore, the bristles are preferably and additionally arranged in bristle planes extending perpendicular to the longitudinal direction and spaced apart from one another in the longitudinal direction. Each bristle in a row of bristles is then also located in a bristle plane.

[0139] Preferably, the support points are located between successive bristle levels.

[0140] At this point it should be mentioned that the above-mentioned arrangement of the bristles also defines the corresponding form of the bristle field cavity.

[0141] The injection molding tool has at least two bristle field tool parts, which can be moved from an open state to a closed state. In the closed state, the bristle field tool 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 tool 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 tool parts. Through this opening, a support core can be inserted longitudinally into the bristle field cavity. Furthermore, a fixing element is provided, which serves to fix the support core inserted into the bristle field cavity.

[0142] Depending on the arrangement of the bristles, it may be necessary to provide more than two bristle field mold parts, which form the bristle field cavity when closed. This can prevent forced demolding.

[0143] The injection molding tool preferably has two handle tool parts that can be moved from an open position to a closed position. In the closed position, the handle tool parts define a handle cavity with a handle cavity opening, wherein this handle cavity serves for the injection molding of a handle part of the brush, in particular the interdental brush. The bristle field tool parts, moved into the closed state, together with the support core inserted into the bristle field cavity and preferably already fixed with the fixing element, can be moved towards the handle tool parts in such a way that the bristle field cavity opening and the handle cavity opening are connected to one another, and the bristle field cavity, together with the handle cavity, optionally with a neck cavity, form an injection cavity.

[0144] Preferably, a hot runner for feeding the liquefied plastic into the injection cavity opens into the handle cavity. The resulting injection point is preferably located in the handle of the interdental brush.

[0145] The bristle field tool parts can define more than one bristle field cavity, each with a bristle field cavity opening. This is especially true when two cooperating bristle field tool parts are sufficient.

[0146] A wire, especially 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 is, depending on the length of the bristle support stem, between 5 mm and 25 mm, preferably 13 mm and 20 mm.

[0147] The length of the support core is preferably chosen so that it ends where the cap-like extension of the bristle support stem begins. However, it is also possible to make the support core long enough to form a uniform surface layer over the entire support core.

[0148] 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, give it a T-shaped or double-T profile, or 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.

[0149] In principle, the support core can also be made curved rather than straight, as long as it can be inserted into the closed bristle field cavity. For example, a banana shape would be possible. However, since inserting the support core becomes more difficult, it is easier to incorporate any curvatures in the bristle support stem after injection molding.

[0150] In the area of ​​the fixation of the supporting core, it is also possible to give the supporting core a structure that improves the fixation.

[0151] For example, a snake shape or a helix, in short shapes that improve the clamping of the supporting core in interaction with the possibly adapted fixing element.

[0152] The sheathing is designed to cap the free end of the supporting core. This way, the preferred steel wire is not exposed to the surface.

[0153] Preferably, the support core, and thus the wire, protrudes 3 mm to 12 mm, preferably 4 mm to 6 mm, above the bristle support stem toward the handle. This preferably extends into the neck section.

[0154] 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.

[0155] In addition to the metal mentioned above, plastic, such as PA or POM, or materials such as Kevlar, can be used for the supporting core. Generally, materials that ensure good restoring torque and do not break under repeated bending are suitable.

[0156] The supporting core can have a special surface structure or surface treatment.

[0157] A smooth surface is good for sliding and can have a negative impact because, depending on the material combination, the supporting core can break away from the sheath due to relative movement between the two elements. For example, if the surface is roughened, the adhesion between the plastic and the supporting core material can be improved. The rough structure can be improved, for example, by etching, introducing nicks, or generally applying a texture.

[0158] To achieve a rough finish, it is also possible to apply a coating to the surface of the supporting core. Suitable materials for this include paints, adhesion promoters, or primers. It is important that the surface coating is not forced away by the spray pressure or damaged by the heat generated during the process.

[0159] The thickness of the sheath (outside the area of ​​the bristles and measured 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.

[0160] Preferably, the diameter of the bristle support stem, ie diameter without bristles, is 0.2 mm to 1.5 mm, preferably 0.35 mm to 0.9 mm.

[0161] The bristle support stem preferably has a length between 6 mm and 16 mm, particularly preferably between 9 mm and 13 mm.

[0162] Particularly preferably, the bristle support stem has a conical outer surface. The diameter of the free end of the support core is preferably 0.35 mm to 0.65 mm, and the handle-side end of the bristle support stem is preferably 0.65 mm to 0.85 mm.

[0163] The bristles preferably have a length of between 0.2 mm and 5 mm, particularly preferably between 0.5 mm and 3 mm, measured from the sheath to the free end.

[0164] 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.

[0165] 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.

[0166] The shell created by the bristle field (at the ends of the bristles) can take on a variety of shapes. For example, the bristles can form a right circular cylinder or a cylinder with a triangular cross-section (pine-tree shape). Shapes are also possible in which the cross-section varies along its length or is irregular at one point. This allows for wave-like or conical shapes. Shapes such as those achieved with twisted brushes can also be realized this way; the degree of complexity offers more possibilities, as the only limits are the injection molding tool.

[0167] 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.

[0168] The bristles are preferably arranged in 2 to 10, particularly preferably 4 to 8, in particular 6 rows of bristles, which run in the longitudinal direction and are evenly distributed in the circumferential direction.

[0169] Furthermore, the bristles are preferably arranged in planes, the so-called bristle planes, which run perpendicular to the longitudinal direction and are preferably spaced at a constant distance in the longitudinal direction. It is also possible to arrange the bristle planes irregularly, i.e., to vary their spacing.

[0170] An angle of preferably 45°, 60°, or 90° is formed between the longitudinal center planes defined by the bristles. Due to the preferably regular arrangement of the bristle rows, this angle is regular across the entire cross-section of the bristle array. An irregular arrangement, i.e., different angles between the bristle rows, is possible.

[0171] The distance between adjacent bristles, measured longitudinally and on the connecting line from center of bristle to center of bristle between the bristles, is preferably between 0.2 mm and 0.8 mm, in particular between 0.4 mm and 0.6 mm.

[0172] Preferably, 10 to 40, in particular 18 to 30, bristles are provided in a bristle row. In this way, between 22 and 400, preferably between 100 and 150, bristles are arranged in the entire bristle array.

[0173] The outer diameter of the bristle field is preferably 1 mm to 6 mm, particularly preferably 1.5 mm to 4 mm.

[0174] The dimensions given for the casing and the bristles naturally also determine the dimensions for the bristle field cavity formed by the bristle field tool parts.

[0175] The parting plane of the bristle field tool parts preferably runs through the bristles of at least one row of bristles. If four rows of bristles are provided, the parting plane preferably runs through the bristles of two diametrically opposed rows of bristles. Particularly preferably, each row of bristles is assigned a parting plane, especially if more than two bristle field tool parts are provided. This simplifies production, provides sufficient venting options for the bristles in the injection molding tool, and finally, the bristle lengths and diameters are not limited by the manufacturing process of the injection molding tool.

[0176] The clamping dies are preferably circular-cylindrical 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 formed by the clamping dies or the passage in the neck area.

[0177] Other alternative cross-sections include oval or n-sided shapes. Round shapes are preferred for plastic flow reasons.

[0178] The clamping dies preferably have teeth or clamping prongs with a height of 0.4 mm to 2 mm, preferably 0.6 mm to 0.9 mm, on their mutually facing end regions (this height is measured from the longitudinal axis 22). With respect to the longitudinal direction, one tooth is preferably provided on one side and two teeth on the other side. The other clamping die is designed in the opposite direction, so that the teeth mesh with each other in the clamping position. There can also be more than three teeth per clamping die.

[0179] It is also conceivable that one clamping die has two opposing teeth which engage in corresponding tooth gaps between two teeth of the other clamping die.

[0180] The length of fixation of the supporting 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.

[0181] This length is preferably evenly distributed among the various elements, such as teeth, meaning they have the same width. Alternatively, it is also possible to vary the widths.

[0182] The position of the fixing elements is preferably selected 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.

[0183] It is also conceivable to use a two- or multi-component injection molding process. For example, it is possible to manufacture the layer or the sheathing and the bristles from one plastic and the handle part from a different plastic. It is also possible to manufacture the sheathing and the bristles, as well as part of the handle, from one plastic and to produce the remaining part of the handle part by overmolding a second plastic. The second plastic can also cover exposed parts of the supporting core.

[0184] Various plastics can be used to make brushes, especially interdental brushes. The materials listed below can be used for a possible plastic core, the bristle area, and the casing or handle. Plastics that form a material bond using multi-component injection molding are preferred.

[0185] A plastic support core is made of a harder plastic than the plastic for the bristle field and the layer or sheath or the handle part.

[0186] Examples of possibilities in the field of thermoplastics are 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 form 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)

[0187] Examples from the field of thermoplastic elastomers (TPEs) are the following soft components: . Thermoplastic polyurethane elastomers (TPE-U) . Thermoplastic styrene elastomers (TPE-S) such as 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)

[0188] Furthermore, the thermoplastics polyethylene (PE) and polyurethane (PU) can be used as hard components as well as soft components.

[0189] Ethylene vinyl acetate (EVA) can be used as a polyolefin.

[0190] PP is particularly suitable as a hard component, with PP having an elastic modulus of 1000–2400 N / mm2, preferably 1300–1800 N / mm2, being the most preferred. TPE-S is preferred as a soft component. The Shore A hardness of the soft component is preferably below 90 Shore A. The soft components form a material bond with the hard component by overmolding in a two- or multi-component injection molding process.

[0191] Example materials for the production of injected bristles: . Polyamide elastomers (e.g., Grilflex ELG 5930 from Ems-Chemie AG). Polyester elastomers (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 MaterialScience or Elastolan 1154 D, 1195 A from BASF).

[0192] The bristle materials have a Shore D hardness of 0 to 100, preferably 30 to 80, particularly preferably 50 to 70.

[0193] So-called bioplastics, plastics made from renewable raw materials, can also be used.

[0194] Using this process and such an injection mold, mascara brushes can also be manufactured. The bristle length for these brushes is 8 mm to 30 mm, preferably 8 mm to 15 mm or 22 mm to 28 mm. The bristles have a length of 1.5 mm to 3 mm. All other dimensions can correspond to those of the interdental brush.

[0195] It is also conceivable to produce 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.

[0196] The support cores are preferably introduced into the bristle field cavity by means of a feed and feeding device. This device can, for example, comprise a magazine with support cores that are separated and then advanced into the bristle field cavity, or a cutting device that separates sections forming support cores from a long supply, which are then fed into the bristle field cavity.

[0197] Alternatively, the support cores are manufactured in an upstream or integrated injection mold. A multi-component injection mold can be used.

[0198] The drawings represent exemplary embodiments.

[0199] They show purely schematically: Fig. 1 in perspective view an interdental brush, which is not part of the invention; Fig. 2 in front view the interdental brush of Fig. 1 ; Fig. 3 in top view the interdental brush of Fig. 1; Fig. 4in view from behind the interdental brush of Fig. 1 ; Fig. 5in bottom view the interdental brush of Fig. 1 ; Fig. 6in side view in the direction of arrow VI of the Fig. 2 the bristle trim of the Fig. 1 to 5 shown interdental brush; Fig. 7 in the same representation as Fig. 2 , but enlarged part of the interdental brush with the bristle; 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 the 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 the line XI - XI of the Fig. 7the interdental brush; Fig. 12 in view and highly simplified a first part of the injection molding tool in the closed state and a second part of the injection molding tool with an open handle cavity and an injection-molded handle of an interdental brush located therein, which is not part of the invention; Fig. 13 a longitudinal section through the injection molding tool along the line XIII - XIII of 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 molding tool in the closed state with an interdental brush in a bristle plane along the line XIV - XIV of 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. 15 the part of the first tool part with an interdental brush injected therein, which is not part of the invention; Fig. 17 in perspective view a part of the first tool part in the opened state in a further embodiment; Fig. 18 in the same view as Fig. 17 the part of the first tool part also in the open state, but with an interdental brush produced therein; Fig. 19a in perspective view a first clamping punch for holding the support core in the injection molding tool; Fig. 19b a second clamping punch, the free end area of ​​which is opposite to that in Fig. 19ashown first clamping die; Fig. 20 in view and schematically the injection molding tool; Fig. 21 a flow diagram for the production of the interdental brush; Fig. 22 simplified flow diagram for possible further processing of the interdental brush produced by injection molding; Fig. 23 in perspective view an embodiment of an interdental brush; Fig. 24 in front view the interdental brush of Fig. 23 ; Fig. 25in view from behind the interdental brush of Fig. 23 ; Fig. 26in side view the interdental brush of Fig. 23 ; Fig. 27in frontal view the interdental brush of Fig. 23 ; Fig. 28in a cross section between bristle planes the interdental brush made of Fig. 23 ; Fig. 29in a cross section between bristle planes the interdental brush made of Fig. 23in a further design variant of the combination of supporting core / sheathing or layer; Fig. 30 in front view a product group of interdental brushes according to Fig. 23-29 ; Fig. 31 in rear view the product group of interdental brushes according to Fig. 23-29 ; Fig. 32 in front view another embodiment of an interdental brush; Fig. 33 in rear view the interdental brush according to Fig. 32 ; Fig. 34in side view the interdental brush according to Fig. 32 ; Fig. 35 in rear view a product group of interdental brushes according to Fig. 32 ; Fig. 36 in front view a product group of interdental brushes according to Fig. 32 ; Fig. 37in frontal view the composite group of interdental brushes according to Fig. 32 ; Fig. 38 in front view another embodiment of an interdental brush; Fig. 39 in rear view the interdental brush according to Fig. 38 ; Fig. 40in side view the interdental brush according to Fig. 38 ; Fig. 41in frontal view the interdental brush according to Fig. 38 ; Fig. 42in rear view a product group of interdental brushes similar to Fig. 38-40 ; Fig. 43in front view the product group of interdental brushes similar to Fig. 38-40 ; Fig. 44 in front view another embodiment of an interdental brush with overmolded wire; Fig. 45 in side view the interdental brush according to Fig. 44 ; Fig. 46 in front view a preferred embodiment of an interdental brush with overmolded wire.

[0200] The Figures 1 to 11The interdental brush 10 shown 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 rectilinearly, over the entire length of the bristle field section 12 and defines a longitudinal direction 22; the dot-dash line indicating the longitudinal direction 22 also defines the longitudinal axis.

[0201] How this particularly affects the Figures 9 to 11can be removed, an elongated support core 24 runs inside the bristle support stem 18 and coaxial with the longitudinal axis 22, which in the illustrated embodiment 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. The support core 24 carries a layer 28 in the area of ​​the bristle field 26, which here forms a casing 28, which, with a cap-like extension 30, encloses the free end of the bristle support core 24 facing away from the neck section 14. The casing 28 is designed in such a way 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 designed to be continuous with the casing 28.

[0202] The sheath 28 and the bristles 20 are injection-molded from the same plastic material from which—in the present case—the handle portion 16 and, in the neck portion 14 connecting the bristle field portion 12 to the handle portion 16, the neck sheath 32 surrounding the support core 24 are also injection-molded. The sheath 28 with the extension 30, the bristles 20, the neck sheath 32, and the handle portion 16 forming the handle 16' are integrally formed with one another and molded in a single injection-molding step.

[0203] Of course, it is possible to form the bristle field section 12 and the neck section 14 in a two-component or multi-component injection molding process, for example with a first plastic component, in order to form the handle section 16 with a second plastic component or, for example, to inject a second component, for example 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.

[0204] The bristle support stem 18 is (slightly) conically widening from the extension 30 to the beginning of the neck section 14.

[0205] The bristles 20 are arranged in bristle rows 34 - in the illustrated embodiment, there are six bristle rows 34 - which run in the longitudinal direction 22 and radially and are evenly distributed in the circumferential direction. Furthermore, the bristles are arranged in bristle planes 36, which run at right angles to the longitudinal direction 22 and are spaced apart from one another in the longitudinal direction 22. In each of the bristle planes 36, there is one bristle 20 of each bristle row 34. For the sake of clarity, the bristle rows are only shown in Figure 6 marked with the reference number 34 and are only available in Figure 8 two bristle levels 36 are shown; in the embodiment shown, twenty-two bristle levels 36 are present.

[0206] The casing 28 has - in the embodiment shown - always centrally between each two adjacent bristle planes 36 straight grooves extending at right angles to the longitudinal direction, defining support points 38, which in cross section are at least approximately semicircular, wherein these support points 38 are arranged offset by 90° from space to space between each two bristle planes 36 in a direction of rotation.

[0207] Between the bottom of these grooves and the supporting core 24, there is at most a thin layer, a film of plastic. However, it is also conceivable that the supporting core 24 is exposed at the bottom of the support points 38. However, due to the sheath 28, it cannot come into contact with the teeth and gums.

[0208] As can be seen further 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.

[0209] In the embodiment shown, the bristles 22 are circular in cross-section and tapered conically outwards in the radial direction, with the ends of the bristles 20 being rounded, here hemispherical.

[0210] The cone angle is between 1° and 2°. Other cross-sections for bristles 20 are, of course, possible; the limits are set by the demoldability of the bristles 20 during the injection molding process.

[0211] Preferred dimensions for the bristle support stem 18, the bristles 20, the support core 24, the sheath 28 and the design of the bristle field 26 are given in the introduction.

[0212] It is also conceivable to design the bristle support stem 18 cylindrically, in particular circularly cylindrically, and / or to arrange the free ends of the bristles 20 in the shell of an imaginary circular cylinder concentric with the longitudinal axis 22, or, as in connection with the Figures 15 to 18 As shown, it is provided in the lateral surfaces of two opposing cones. Other shapes are also possible.

[0213] The sheath 28 continuously transitions into the neck sheath 32 in the neck section 14, where the outer cross-section continuously increases from the neck section 14 toward the handle section 16. Furthermore, the sheath 28 continuously transitions into the cap-like extension 30 in the free end region of the interdental brush 10.

[0214] The neck casing 32 has a passage 40 extending at right angles to the longitudinal direction 22, which in the present case is circular-cylindrical and through which the support core 24 extends centrally. This is visible from the outside. Preferably, the handle-side end of the support core 24 does not lie in the passage 40, but rather an end section of the support core 24 extends from the passage 40 in the direction toward the handle section 16 into the plastic from which the handle 16', the neck casing 32, the casing 28 with the extension 30 and the bristles 20 are made; this is shown in particular Figure 11 .

[0215] In the illustrated embodiment, the grip section 16 or handle 16' is approximately the size of a fingertip, so that it can be easily held by the thumb and index finger. Of course, the grip section 16 or handle 16' can be given any other shape; in particular, it can be made longer.

[0216] The Figures 12 to 14 show a highly simplified embodiment of an injection molding tool 42 for producing the Figures 1 to 11 shown interdental brush 10.

[0217] The injection molding tool 42 has a first tool part 44 for producing the bristle field section 12 and the neck section 14 and a second tool part 46 for producing the handle section 16.

[0218] In the illustrated embodiment, the first tool part 44 is provided with six bristle field tool parts 48, which, when closed, define a bristle field cavity 50 for producing the casing 28, the bristles 20, and the cap-like extension 30. On an 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.

[0219] Furthermore, the first tool part 44 is assigned two bar-like 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 molding tool 42—is arranged near the bristle field cavity opening 54 and is aligned therewith; the neck tool parts 56 rest against 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 facing the second tool part 46.

[0220] Furthermore, each of the neck tool parts 56 is assigned a clamping punch 64. The clamping punches 64 are located radially opposite one another with respect to the longitudinal direction 22, which is defined by the bristle field cavity 50, and are movable along a straight line that runs at right angles to the longitudinal axis 22 and intersects it, from a rest position in which they are spaced apart from one another, towards one another into a position in the Figure 13 shown clamping position movable; this mobility is indicated by double arrows.

[0221] The clamping stamps 64 together form a fixing element 64' for fixing the support core 24.

[0222] The second tool part 46 has two handle tool parts 66, which form a handle cavity 68 in the closed state. For the sake of clarity, Figures 12 and 13 only one of the handle tool parts 66 is shown.

[0223] The handle cavity 68 has a handle cavity opening 70 on a side facing the neck cavity 58, which - in the closed state of the injection mold - is arranged adjacent to the second neck cavity opening 62 and is aligned with it.

[0224] In the closed state of the injection molding tool 42, the bristle field cavity 50, the neck cavity 58 and the handle cavity 68 together form an injection cavity 72.

[0225] As is generally known and also from 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, 68 are thus also derived from the dimensions of the interdental brush 10 stated in the introduction. The shapes of the cavities 50, 58, and 68 result from the interdental brush 10 shown in the figures.

[0226] As this is particularly the case with Figure 13 which, when the second tool part 46 is opened on one side, also shows an interdental brush 10 produced in the injection molding tool 42, the support core 24 is held clamped during the injection molding of the plastic by means of the clamping punches 64 forming the fixing element 64'.

[0227] If the plastic is injected into the handle cavity 68, it flows through the neck cavity 58 into the bristle field cavity 50 without the support core 24 being able to be displaced in the longitudinal direction 22.

[0228] In addition, the Figure 13 Support elements 74 are shown, which are formed on bristle field tool parts 48 and correspond inversely to the support points 38 described in connection with the description of the interdental brush 10. The support elements 74 protrude toward the interior of the bristle field cavity 50 and thus form the support points 38.

[0229] How this continues the Figure 13 can be removed, the bristle field cavity 50, in the closed state of the injection molding tool 42, continuously merges into the neck cavity 58 and this continuously merges into the handle cavity 68, thus forming the injection cavity 72. It is of course conceivable to form steps, grooves or grooves at these transition points.

[0230] As can be seen 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.

[0231] Moreover, Figure 14 the bristles 20 arranged in one of the bristle planes 36, which are manufactured integrally with the casing 28 of the supporting core 24 by injection molding.

[0232] In connection with the Figures 12 to 14 The basic principles of the procedure can already be discussed.

[0233] In the illustrated embodiment, the bristle field tool parts 48 are transferred in the radial direction relative to the longitudinal direction 22 into the closed state of the first tool part 44, after which they form the bristle field cavity 54, which has the bristle field cavity opening 54 on the end face 52. The support core 24 (arranged in the longitudinal direction) is then inserted in the longitudinal direction 22 through the bristle field cavity opening 54 into the bristle field cavity 50 and subsequently held in place by means of the clamping dies 64.

[0234] In this case, either the support core 24 is first inserted into the neck tool part 56 and clamped and then introduced into the bristle field cavity 50 by moving the neck tool part 56 to the end face 52 of the bristle field tool parts 48, or the neck tool part 56 is moved to 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.

[0235] By injecting plastic into the bristle field cavity 50, the sheath 28 and thus the bristles 20 are formed integrally.

[0236] The plastic is introduced into the bristle field cavity 50 through the bristle field cavity opening 54.

[0237] In the embodiment shown, the support 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.

[0238] In the illustrated embodiment, the clamping dies 64 are assigned to the neck tool parts 56, which—in the closed state—delimit the neck cavity 58 connected to the bristle field cavity 50. Thus, the neck casing 32 is also molded simultaneously and integrally with the casing 28 and the bristles 20.

[0239] The clamping stamps 64 are surrounded by the plastic and the passage 40 is formed in the neck jacket 32.

[0240] 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 dies 64, is moved to the second tool part 46 so that the second neck cavity opening 62 is positioned adjacent to the handle cavity opening 70. With the handle tool parts 66 in the closed position and the handle cavity 68 thus closed, the plastic is injected into the latter, which also passes through the neck cavity 58 into the bristle field cavity 50.

[0241] For demolding, the handle cavity 68 is first opened by lifting the handle tool parts 66 apart. 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 die 64 from the clamping position in the radial direction outside the neck cavity 58 and opening the neck cavity 58 by moving the neck tool parts 56 away from each other, as well as opening the bristle field cavity 50 by moving the bristle field tool parts 48 away from each other in the radial direction, the interdental brush 10 is completely demolded.

[0242] The Figures 15 to 18show a perspective view of the first tool part 44 for the production of interdental brushes, as shown in the other figures and described above. The difference in tool construction compared to the figures already shown and described is 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 Figs. 15 and 16 visible, but not shown for clarity.

[0243] The differences on the product side lie in the design of the bristle field 26 and in the shape of the handle 16'. All bristles 20 are again arranged in six circumferentially evenly distributed bristle rows 34, and all bristles 20 are located in bristle planes 36 that are arranged at a constant distance from one another in the longitudinal direction 22. In each bristle plane 36 there is one bristle 20 of each bristle row 34. However, the free ends of the bristles 20 are no longer located on a single conical surface, but rather they end in two oppositely directed conical surfaces, which emanate with their smaller diameter from the axial ends of the bristle field 26 and meet at least approximately in the middle.

[0244] Of course, other designs of the bristle field 26 are also possible with the injection molding tool 42 shown, including those shown in the Figures 1 to 11shown; only the bristle field cavity 50 needs to be formed accordingly.

[0245] Further, how this affects the Figures 16 to 18 The handle 16' is cuboid-shaped 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.

[0246] Figure 15 shows a perspective view of three of the six bristle field tool parts 48, 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 molding tool 42. Furthermore, Figure 15one of the two bar-shaped neck tool parts 56 is shown, which in the closed position of the second tool part 46 lies in the axial direction against the bristle field tool parts 48, ie the front side 52, such that the bristle field cavity opening 54 is located at the first neck cavity opening 60. Furthermore, in Figure 15 One half of the neck cavity 58 is shown, into which the clamping punch 64 associated with this neck tool part 56 projects. The two neck tool parts 56 (with the exception of the clamping punches 64) are shaped in opposite directions, at least at the interface, and delimit the neck cavity 58 when the injection molding tool 42 is closed. The opposite direction of shape is advantageous in order to enable uniform filling during the injection molding process when the plastic is introduced.

[0247] 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 forming 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 and the cap cavity 82 are 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 moved out of the remaining first tool part 44.

[0248] Further in the Figure 15the support core 24 is shown, which has been introduced 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 transferred into the closed state.

[0249] Further in the Figure 16 dovetail-like guide slots 96 for the bristle field tool parts 48 are shown. The corresponding radial guides 84 are formed on a support body 86, the structure of which also Figures 17 and 18 can be removed.

[0250] For the sake of completeness, it should be mentioned that the parting planes 76 are again located in the longitudinal center planes 78 of the bristle rows 34. Furthermore, bristle field tool parts 48 have support elements 74 (see Figure 14 ), which serve to center the support core 24 in the bristle field cavity 50.

[0251] The Figure 16 shows in the same representation as Figure 15an interdental brush 10 produced in the injection molding tool 42. In the passage 40 in the neck casing 32, which is kept free of plastic during injection molding by the two clamping dies 64, on the one hand the exposed fixing section 88 of the supporting core 24 (see also Figures 2 , 4 , 7 , 11 and 14 ) and on the other hand the clamping stamp 64 is visible, which is still shown in the clamping position.

[0252] In the Figure 17The first tool part 44 is shown in the open state. The cylindrical support body 86 has (on the end face 52) a front plane 90 extending at right angles to the longitudinal direction 22 and facing the neck tool parts 56. The support body 86 has six guide grooves 92 extending radially with respect to the longitudinal direction 22 and evenly distributed in the circumferential direction, in the present example, which are open in the front plane 90. A bristle field tool part 48 is inserted into each of these guide grooves 92 and is mounted therein for radial displacement.

[0253] In the Figures 15 and 16(not shown in the figures), the side surfaces of the guide grooves 92, which abut 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 diametrically opposed guide slots 96, into which the radial guides 84 engage. The said guide slots are in Figs. 15 and 16 shown.

[0254] 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 counter-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 the figures.

[0255] 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 position in the axial direction with respect to the longitudinal direction 22 and to guide them in a translationally movable manner in the radial direction.

[0256] The bristle field tool parts 48 are cuboid-shaped, whereby in the Figures 15 to 18In the embodiment shown, two opposite sides (broad sides) are provided with the guide slots 96.

[0257] In the radially inner end region, the bristle field tool parts 48 are shaped like a gable roof, with the gables 100 extending in the longitudinal direction 22 and the roof surfaces 102 forming the parting planes 76. This means that, in the closed state, the roof surfaces 102 of adjacent bristle field tool parts 48 abut one another. 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.

[0258] Corresponding groove-like recesses are formed in the roof surfaces 102, which, when the bristle field tool parts 48 are closed, 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.

[0259] In the radially outer end region, the bristle field tool parts 48 have dovetail-like guide projections 104, which in their imaginary extension form an acute angle with the longitudinal axis 22. The guide projections 104 are guided in opposing sliding grooves of a control ring, which surrounds the support body 68 and is displaceable back and forth in the axial direction by means of a drive element. In one axial end position of the control ring, the bristle field tool parts 48 are in abutting relation in the closed state and form the bristle field cavity 50, as shown in the Figures 15 and 16 In the other end position of the control ring, the bristle field tool parts 48 are in the open position radially outward, as shown in the Figures 17 and 18 is shown.

[0260] As can be seen from the Figures 17 and 18 compared with the Figures 15 and 16As further shown, the neck tool parts 56 are mounted displaceably in the longitudinal direction 22 relative to the bristle field tool parts 48 and also the support body 86; longitudinal bearings are generally known and are not shown for the sake of clarity. Drive elements for moving tool parts are also generally known and are not shown.

[0261] In Figure 18 the first tool part 44 is also in the open position, but in addition, as shown in Figure 16 , an interdental brush 10 produced with the injection molding tool 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.

[0262] The operation of the injection molding tool 42 is described below in connection with the Fig. 21 described.

[0263] The Figures 19a and 19bshow a preferred embodiment of the two clamping stamps 64 forming a fixing element 64'.

[0264] The clamping punches 64 have teeth 112 and oppositely shaped tooth gaps 114 in their mutually facing end regions 110, wherein in the clamping position the teeth 112 engage in the tooth gaps 114 of the respective other clamping punch 64.

[0265] In the embodiment shown, the clamping punches 64 have a circular profile-shaped cross-section, wherein the mutually facing ends are provided with a punch recess 116 which is V-shaped in cross-section and runs in the longitudinal direction 22.

[0266] At the bottom of the punch recess 116, the clamping punches 64 each have a groove 118 running 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 such that in the clamping position of the clamping punches 64, the support core 24 can be held clamped by the grooves 118.

[0267] When in Figure 19a In the clamping punch 64 shown, the flanks 120 formed by the punch recess 116 are divided centrally in the longitudinal direction 22 by a transverse recess 122 into two teeth 112 each. The transverse recesses 122 form tooth gaps 114 in the flanks 120, which are opposite to the Figure 19b shown clamping punch 64 formed teeth 112.

[0268] When in the Figure 19bIn the clamping punch 64 shown, the two flanks 120 formed by the punch recess 116 are each formed into a tooth 112 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 Figure 19a shown clamping stamp 64.

[0269] If the two clamping dies 64, which are located on a common axis, are moved towards each other, the two teeth 112 of the Figure 19b shown clamping punch 64 engages with the tooth gaps 114 of the Figure 19a The four teeth 112 of the clamping die 64 shown in the Figure 19a indicated clamping stamp 64 into the outer tooth gaps 114 of the Figure 19b shown clamping stamp 64 into engagement.

[0270] In the clamping position, the support core 24 is thus completely enclosed by the clamping dies 64 in the fixing section 88. Furthermore, the two clamping dies 64 form a continuous profile in the clamping position, which serves to form the passage 40 during injection molding.

[0271] The Figure 20 shows schematically 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 rotation axis 124 and, after each rotation of 90°, can be moved one after the other to the second tool part 46.

[0272] The second tool part 46 has the two handle tool parts 66, which, when closed, form the handle cavity 68. It should be noted at this point that the first tool parts 44 and the second tool part 46 can each form a plurality of corresponding cavities in order to simultaneously produce a plurality of interdental brushes, as is generally known from toothbrush production.

[0273] Each of the first tool parts 44 has, on the side facing the second tool part 46, the two neck tool parts 56, which, when closed, form the neck cavity 58 or the 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. The bristle field tool parts 48 are located between the neck tool parts 56 and the respective cap tool part 80. The first tool parts 44 are designed as described above and illustrated 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 rotation axis 124 or the longitudinal direction 22.

[0274] The design of the injection mold 42 according to Figure 20enables short cycle times for the production of the interdental brushes 10. Since each first tool part 44 occupies four different positions in which different actions can be carried out, as is the case in connection with the Figure 21 as set out below.

[0275] In a first position A, the bristle field cavity 50 is closed by moving the bristle field tool parts 48 into the closed state. Furthermore, the neck tool parts 56 are moved toward each other into the closed position and in the longitudinal direction 22 into contact with the bristle field tool parts 48. The clamping dies 64 and the fixing element 64' are held spaced apart from one another in the rest position, outside the neck cavity 58.

[0276] Then this first tool part 44 - in the Figure 20shown embodiment by rotating through 90° about the rotation axis 124 - into a second position B. In this second position B, the support core 24 is inserted through the neck cavity 58 and then through the bristle field cavity opening 54 in the longitudinal direction 22 into the closed bristle field cavity 50, after which the clamping punches 64 are moved towards one another or the fixing element 64' is moved into the clamping position.

[0277] The support core 24 can be supplied to the process either as a pre-cut part (e.g., a cut part) or as a continuous part. In the latter case, the support core 24 must be cut to the correct length during the process. It is also possible to mold the support core 24 from a plastic material, for example, in a separate or integrated injection molding process, thus allowing an interdental brush to be manufactured entirely from plastic.

[0278] Then, again by rotation, the first tool part 44, with the support core 24 inserted and held therein, is moved into a third position C, in which the first tool part 44 is located near the second tool part 46. The handle cavity 68 is closed by moving the handle tool parts 66 toward one another. Furthermore, the first tool part 44 and the second tool part 46 are moved toward one another and positioned adjacent to one another, so that the handle cavity 68, together with the neck cavity 58 and the bristle field cavity 50, including the cap cavity 82, form the injection cavity 72.

[0279] The plastic is then injected into the handle cavity 68, whereby the handle 16' is formed in the handle cavity 68, the neck jacket 32 ​​is formed in the neck cavity 58, the jacket 28 is formed in the bristle field cavity 58, and the bristles 20 and the extension 30 are formed in the cap cavity 82.

[0280] Once the plastic has cured at least sufficiently to retain its shape, the handle cavity 68 is opened by moving the handle tool parts 66 away from each other. This demolds the handle 16'. The first tool part 44 and the second tool part 46 are then moved away from each other. The first tool part 44 is then rotated into a fourth position D.

[0281] In this position D, it is possible to inject a second component, for example, a hard or soft component, onto the already manufactured handle 16'. If desired, a third tool part of the injection molding tool 42 is located in this fourth position D, which can be designed identically to the second tool part 46, but only the cavities next to the receptacle for the already manufactured handle 16' are designed for injecting the additional component.

[0282] The already manufactured handle 16' protrudes beyond the neck mold parts 56 and enters the respective cavity in the fourth position D. The mold parts are moved toward one another, the cavity is closed, and then the second component is molded. After this component has at least partially cured, the additional handle cavity is opened, and then the first mold part 44 is returned to the first position, position A. In this position, the bristle field mold parts 48 are moved into the open state, exposing the bristle field section 12 and the handle section 16 of the interdental brush 10.

[0283] By moving the neck tool parts 56, which are in the closed position, away from the bristle field tool parts 48 in the longitudinal direction 22, the interdental brush 10 is removed from the bristle field cavity 50. Subsequently, the neck tool parts 56 and the clamping dies 64 or the fixing elements 64' are moved away from each other, and the clamping dies 64 are moved into their rest position beforehand, simultaneously, or subsequently. The interdental brushes 10 are free and can be removed from the injection molding tool 42, for example, by means of a gripper (e.g., on a robot).

[0284] Depending on the design, the gripper already holds the interdental brushes 10 when the neck tool parts 56 and the clamping punches 64 are opened. Another design option, depending on the design of the injection molding tool, is to simply drop the manufactured parts.

[0285] Subsequently, the first tool part 44 or its parts are closed again as described above and a new production cycle can begin.

[0286] The Figure 20 The embodiment shown with four first tool parts 44 thus has the advantage of large production capacity, whereby while the first component of an interdental brush 10 is being injected, actions are carried out in the remaining positions.

[0287] If it is not intended that a second component is injected onto the handle 16', the fourth position D can be omitted, as shown in the Figure 21 is shown by a dashed line 126. In this case, the injection molding tool 42 advantageously has three first tool parts 44, which are rotated from position to position, preferably by 120° each, about the rotation axis 124.

[0288] In this case, however, it is also possible, for example, to divide the activities from one position into several positions. For example, at position A, the opening and product removal can be grouped together and separated from the closing and merging of the tool parts.

[0289] Furthermore, it is conceivable, as in Figure 21 indicated by the dashed line 126', to insert the support core 24 in the first position A into the closed bristle field cavity 50.

[0290] In this case, if no second component needs to be molded onto the handle 16', it is advantageous to provide two first tool parts 44, each of which is rotated 180° around the rotation axis 124 into the corresponding positions (A, C). However, if the injection of a second component is intended, the injection molding tool 42 preferably has three first tool parts 44.

[0291] Preferably, the respective first tool parts 44 are arranged in the manner of the blades of a helicopter rotor, evenly distributed in the circumferential direction relative to the axis of rotation 124 and fastened to a central rotating part.

[0292] Possible further processing of the interdental brushes 10 produced as described above will be discussed in connection with Figure 22 received.

[0293] In Figure 22 It demonstrates how the injection molding process and the subsequent manufacturing steps are integrated into the overall production process using an inline solution, meaning the manufacturing steps are directly linked. The advantages of this manufacturing method are obvious. For example, they are economical in nature; no intermediate storage is required, and damage to the bristle field can be virtually eliminated.

[0294] For example, it is possible to rework the injected interdental brushes 10 in several steps and then package them directly. Furthermore, it is possible to provide a buffer between the multiple processing steps. The buffer serves to cushion fluctuations in performance between the preceding and subsequent process steps.

[0295] Thus, it is possible for the injected interdental brushes 10 to be provided with a label, for example, by embossing or printing, in a subsequent step after injection molding. Post-processing can also affect the bristle area; for example, the interdental brush 10 can undergo a further curvature of the bristle support stem 18. Treating the bristle area 26 with substances, such as dental solutions, toothpastes, or disinfectants, is also possible. Applying heat to the bristle area 26 is also possible, as is twisting the bristle area 26 to give it a torsion shape.

[0296] The above-mentioned processing operations can be carried out before or after buffering or directly before packaging the interdental brushes 10.

[0297] Further processing is also possible inline before the interdental brushes 10 are packaged.

[0298] It is also conceivable to further process the manufactured interdental brushes 10 offline. For this purpose, the individual steps can be completely separate and take place independently of one another. It is possible for each intermediate product to be stored before further processing.

[0299] In addition to the stated variant, where the product is manufactured entirely in an injection mold and is a "stand-alone" product, it is also possible to manufacture a subset of the product. Instead of the complete 16' handle, it is possible to design an interface geometry that fits onto a similarly shaped part of a handle. The brush part is replaceable and is clicked into the handle or removably attached in another way.

[0300] It is also possible to design the interdental brush as identically as possible to an existing twist-in brush, for example, by injecting a plastic handle into it. This allows existing twist-in brushes without a handle to be replaced 1:1. This is used, for example, in handles into which simple twist-in brushes can be inserted. The twist-in brushes are held / clamped by bending the extension of the bristle stem.

[0301] It is also possible to use the co-injection process to manufacture the interdental brushes mentioned. 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 it has partially hardened, a second material component is injected through the same injection point so that this component either displaces the existing partial component and takes up this space inside the existing component, or the additional component breaks through the existing component. This makes it possible to produce a two-component part in a single injection molding cavity. In this way, for example, the handle and bristles can be different colors, or different materials can be used for the handle and bristles.

[0302] In the Figures 23 to 29a variant of an interdental brush 10 is shown, in which the supporting core 24 is also made of a plastic by injection molding.

[0303] 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 protrude, also extends in this variant in a straight line over the entire length of the bristle field section 12 and defines a longitudinal direction 22; the dot-dash line indicating the longitudinal direction 22 again defines the longitudinal axis.

[0304] In the present case, the handle 16', the neck element 32, and the support core 24 are integrally molded from a 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 sheath 28 is 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.

[0305] The handle 16' has a flattened shape for the most efficient handling possible. The flattened shape can be in the form of a small plate, which optionally has trough-shaped indentations on the top and / or bottom for accommodating fingertips (not shown). Knobs can also be arranged in the trough-shaped indentations to further increase grip. The bristles 20 or the bristle field 26 are injection-molded together with the casing 28. The casing 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 support core 24. The handle 16' can also be provided with another plastic component, in particular a soft component, for better ergonomics / functionality.

[0306] In the present case, the bristle field 26 consists of bristles 20, which protrude essentially from 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 protrude radially from the longitudinal axis 22 of the support core 24; rather, the individual rows 34 of bristles extending in the longitudinal direction 22 are each arranged at least approximately parallel or at a 90° angle to one another. As in Figure 27As can be seen, the upper three, approximately parallel, rows of bristles 34 follow the taper of the support core 24 or the casing 28 (which generally has a constant thickness and therefore also extends with a corresponding taper around the support core 24) and converge somewhat pointedly, while the lateral rows of bristles protrude perpendicularly from the support 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.

[0307] In Figure 29 is one of the Figures 23-28 An alternative cross-section is shown in the area between the rows of bristles. The support core 24 emerges from the sheathing in the area of ​​the bristle field section 12 and thus forms at least part of the actual rear side of the bristle field 26. The support core 24 is thus partially surrounded by a sheathing or layer 28, with the exception of the lower side.

[0308] The support core 24 is preferably designed in the shape of a rounded trapezoid. However, the support core can also be triangular and completely surrounded by the casing 28 on two sides and not at all or only partially on one side. However, the support core can also have a round cross-section.

[0309] The support 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.

[0310] The production of an interdental brush 10 according to the Figures 23 to 29is 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 produced in the two-component or multi-component injection molding process. As in the previous embodiments, the support core 24 is inserted in the longitudinal direction 22 through the bristle field cavity opening 54 into the closed bristle field cavity 50. Furthermore, it is also possible to produce the support core 24 in a separate injection mold and then feed it to the injection mold in which the bristle field is formed and insert it accordingly into the injection molding cavity.

[0311] The support body 24 is preferably fixed in the injection mold in the region of the handle 16', at locations where only one plastic component is present (i.e., in particular, not at locations 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 casing 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 casing 28 covers a small part of the surface on the handle 16', while on the back of the interdental brush 10, on the neck element 14, it covers a substantial part of the surface of one side before finally completely covering the surface in the bristle field section 26 (cf. Figure 25 ).

[0312] It is also possible to combine the molded bristles 20 with twisted bristles, so that, for example, the front part of the interdental brush 10 has twisted bristles. For this purpose, a twisted brush is produced in a first step, if necessary, which has twisted bristles at its front end and is equipped with twisted wire at its rear part. This part is inserted into the injection molding cavity, clamped, and also clamped in front of the area of ​​the twisted bristles. The twisted wire is then overmolded and provided with molded bristles 20.

[0313] The Figures 30-31 The product group 200 shown has several brushes of the type Fig. 23-29shown embodiments of the description. Preferably, a product group consists of five brushes, as shown. As can be seen, the adjacent brushes are connected to one another in the region of their handles 16' by means of two material bridges 128.

[0314] The material bridges 128 are of equal or different lengths, depending on the design of the handle 16'. They can also each have a predetermined breaking point S, for example in the form of a perforation or a notch or a weakened material, at which the individual brushes can be easily and cleanly separated from one another.

[0315] 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, wherein the second plastic component covers a small part of the surface on the handle 16', while on the back side on the neck element 32 it covers a substantial part of the surface and the surface of the support core 24 completely, or with the exception of a lower side (cf. Fig. 29 ), covered.

[0316] The second plastic component is introduced into the product at a separate injection point 51" for each interdental brush 10. The first plastic component is introduced via the injection point 51'. It is possible for a product group to have only one injection point 51' of the first component, or for there to be multiple injection points 51'. The injection points are preferably arranged regularly or symmetrically with respect to the arrangement on the products of the product group. Furthermore, the injection point 51' or 51" is always located at the same position within the individual product. Preferably, no more than one injection point is used per plastic component per product.

[0317] The other components correspond to those described in the Fig. 23-29 The parts / components shown here. A hot runner system is typically used for this embodiment. The use of a cold runner system is also conceivable.

[0318] 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 support core (here concealed by the layer / sheath 28) extend. As can be seen, three converging rows of bristles 34 (of which the middle one 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 substantially horizontally from the support core (or bristle stem 18), define the bristle field 26.

[0319] The bristles 20 decrease in length in the direction of the end of the bristle stem 18 facing away from the neck element 32. As is particularly evident in Fig. 34As can be seen, the two rows of bristles 34, which protrude essentially horizontally from the support core, are arranged in a plane below the longitudinal axis 22 of the support core 24. Due to the fact that in the present case the support core and the bristle stem 18 taper towards their end facing away from the neck element 32, the plane in which the essentially horizontally arranged rows of bristles lie may not be entirely parallel to the longitudinal axis 22. The handle 16' of the brush is flat in the present case. The cap-like extension 30 of the layer / sheath 28, in turn, encloses the free end of the support core facing away from the neck element 32. The injection point 51" for the second plastic component is located either at the free end of the support core or at the end of the support core facing the neck element 32 (i.e., in the bristle field cavity opening).No second plastic component is applied to the handle 16' and the neck element 32 of the individual brushes. A cold runner system is typically used in this embodiment. The injection point 51" is preferably located at the free end of the support core.

[0320] The Figures 35 and 36 The correspondingly illustrated product group 200' 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 or a notch or a material weakening.

[0321] Accordingly, no second plastic component is applied to the handle 16' and the neck element 32 of the individual brushes. In the front view according to Figure 37The connection of the brushes of product group 200' via the individual material bridges 128 between the handles 16', as well as the previously described geometry of the bristle array 26, can be seen again. The support core 24 has a trapezoidal cross-section. Preferably, a product group 200' again consists of five brushes.

[0322] In the Figures 38-40 In the brush shown, two rows of bristles 34 are arranged on the upper side of the support core 24 or bristle stem 18, which rows of bristles converge in the direction of 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 illustrated, project outwardly inclined (ie not substantially vertically but also not radially) from the upper side of the support core 24. In addition, two rows of bristles 34 projecting substantially horizontally from the support core 24 or from the bristle stem 18 are provided.

[0323] The cap-like extension 30 of the layer / sheathing 28 also encloses the free end of the support 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, wherein the second plastic component on the handle 16' covers a large part of the surface both at the front and at the back, while on the rear side it is attached to the neck element 32 (cf. Figure 39 ) covers a substantial part of the surface and completely covers the surface of the support core 24.

[0324] However, there is also the possibility that analogous 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 trough-shaped recess 17 on both the front and back sides for better grip, as shown in Fig. 40can be seen. On the back of the handle 16' (cf. Figure 39 ), the second material component is guided in an elongated recess 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 recess of the handle 17 and the elongated recess 19 of the neck element 32 to the support core, where it finally forms (in the corresponding bristle field cavity) the layer or sheath 28 with the bristles 20. In Figure 38 one recognizes the support points 130 at which the support elements 74 of the bristle field cavity 50 (cf. analog Figure 13 ) and prevent the support core 24 from moving in the radial direction and possibly closing the openings for the individual bristles 20 to be formed. For this variant, a hot runner system is generally provided so that the second plastic component does not solidify prematurely on its relatively long flow path.

[0325] A product group 200" with brushes, which meet the requirements Figures 38-41 are very similar to the brushes shown, is shown in the Figures 42-43 Only the shape of the handles 16' differs from the oval shape according to the Figures 38-40 away.

[0326] The present handle shape of the brushes is essentially rectangular and has a lateral indentation 131 on each side. This is due to the fact that, in this case, the individual brushes of the 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' are formed from the second plastic component.

[0327] The material bridges 128 made of the first plastic component are each arranged in the rear region of the handle 16', and the material bridges 128' made of the second plastic component are each arranged in the front region of the handle 16'. With this configuration, a spray point for the second plastic component does not need to be present on each brush.

[0328] The handles 16' (including the neck element and support core), initially molded from the first plastic component, are positioned close together. Furthermore, the handles 16' have transitions 132 on the top and back sides in the area of ​​the second material bridge 128' (to be molded later), over which the second plastic component can be distributed. Thus, an injection point for the second plastic component does not have to be provided on each product or brush. This product group 200" also preferably consists of five brushes each.

[0329] 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, such as a cup or glass. In the schematically illustrated exemplary embodiment, this is an interdental brush with an overmolded wire or support core 24, which protrudes from the neck element 32 and carries a bristle array 26.

[0330] 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 notch 134 are resilient and can thus be applied to the holder 140, the glass, the cup, or the like in a form-fitting and friction-fitting 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 notch 134 is overmolded with a border 135 made of a second or further plastic component, which is usually a soft component. This can further improve the grip of the brush on the respective holder 140. In the present case, the border 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 lateral view according to . Figure 45 As can be seen, the lateral flanks 136 taper towards their lower end. Such a notch 134 and border 135 can of course also be used in an interdental brush with a plastic injection-molded core, as shown in the Figures 23-43 illustrated (as well as in corresponding product groups).

[0331] The injection point for the first plastic component 51' is located in the embodiments according to the Figures 23 to 46 Preferably in the handle area. Depending on the design, one or more injection points per product or product group are conceivable. Preferably, one injection point is provided, with the plastic material distributed within the individual product and across the material bridges.

[0332] The respective brushes according to the Figures 23 to 46 can be molded and easily demolded in the parting line of a two-part injection mold, enabling particularly cost-effective and efficient production. The injection mold for these designs also typically requires no neck mold parts or clamping dies.

[0333] Of course, the design variants shown in this document are exemplary. The interdental brush of the invention can be combined with some of the features described, provided they are compatible.

[0334] The descriptions given for specific figures can of course also be transferred to other figures that show the same or similar characteristics and in which the characteristics are not described in the same detail.

Claims

1. Interdental brush, comprising a bristle support stem (18) which defines a longitudinal direction (22) and has an elongate support core (24), a bristle field (26) with bristles (20) protruding from the bristle support stem (18) and a neck element (32) connecting the support 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 plastics component consisting of hard material, and wherein a second plastics component consisting of soft material in the form of an integral layer (28) with bristles (20) protruding therefrom is molded onto the support core (24), wherein each of the parts molded from the first plastics component, i.e. the handle (16'), the support core (24) and the neck element (32), has troughs or channels which enable or at least assist a flow of the second plastics component, wherein the integral layer (28) consisting of soft material is molded onto the support core (24) so as to be flush with the neck element (32).

2. Interdental brush according to claim 1, wherein the handle (16') has a notch (134) at its end remote from the neck element (32).

3. Interdental brush according to claim 1 or 2, wherein, between the handle (16') and the neck element (32), transition points are provided at which steps, grooves or flutes are formed in the second plastics component by the injection molding of the second plastics component in an injection cavity (72) of an injection molding tool.

4. Interdental brush according to any of the preceding claims, wherein the handle (16') has a flattened shape, preferably in the form of a plate.

5. Interdental brush according to claim 4, wherein the handle (16') has, on the upper and / or lower side, a trough-shaped indentation (17) and / or one or more holes for accommodating fingertips.

6. Interdental brush according to claim 5, wherein the second plastics component and optionally a further plastics component are introduced into the trough-shaped indentations (17) and / or holes, preferably forming a portion with increased grip.

7. Interdental brush according to claim 5 or 6, wherein the trough-shaped indentations (17) are provided with a structure, wherein the structure is preferably arranged on the edge or on the bottom of the trough-shaped indentation (17) and wherein further preferably the structure is designed in the form of knobs, grooves, lamellae or combinations thereof.

8. Interdental brush according to any of claims 5 to 7, wherein closed and / or open trough-shaped indentations (17) are provided, wherein in the closed version the edge of the trough-shaped indentation (17) is continuous and wherein in the open version the trough-shaped indentation (17) is open on at least one side.

9. Interdental brush according to claim 8, wherein in the open version the trough-shaped indentation (17) is open at the front and back.

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

11. Interdental brush according to claim 10, wherein the thickness of the sheath (28), outside the region of the bristles (20) and measured in the radial direction with respect to the longitudinal direction, is between 0.05 mm to 0.3 mm, preferably 0.1 mm to 0.2 mm.

12. Interdental brush according to any 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 1 mm to 2 mm, and preferably a width of 3 mm to 12 mm, preferably 5 mm to 8 mm.

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

14. Interdental brush according to any 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.

15. Interdental brush according to any of the preceding claims, wherein the bristle material has a Shore D hardness of 0 to 100, preferably 30 to 80, and particularly preferably 50 to 70.

16. Interdental brush according to any of the preceding claims, wherein the hard material is preferably made of polypropylene and has an E-modulus of 1000 N / mm2 to 2400 N / mm2, preferably 1300 N / mm2 to 1800 N / mm2.