Cleaning unit for an oral hygiene device and oral hygiene device

Abstract

The cleaning part for an electric oral hygiene device comprises a carrier attached for driven rotation and / or oscillating rotation around a rotation axis, and at least a plurality of first cleaning elements and a plurality of second cleaning elements, the cleaning elements being attached to the attachment surface of the carrier. The carrier has an outer edge and an inner part. The plurality of first cleaning elements are arranged on the inner part of the carrier, and the plurality of second cleaning elements are arranged on the outer edge of the carrier. The plurality of first cleaning elements have a longitudinal axis and a substantially cross-shaped cross-sectional area extending in a plane substantially perpendicular to the longitudinal axis, the cross-shaped cross-sectional area having four protrusions and four channels, the protrusions and channels being arranged alternately.

Description

Technical Field

[0001] The present disclosure relates to a cleaning part for an electric oral hygiene device, which includes a carrier attached for driven rotation and / or oscillating rotation about a rotation axis, and at least a plurality of first cleaning elements and a plurality of second cleaning elements, wherein the cleaning elements are attached to the attachment surface of the carrier. The present disclosure further relates to an electric oral hygiene device including such a cleaning part and a handle, wherein the cleaning part is repeatedly detachable from the handle.

Background Art

[0002] Bristle tufts composed of a plurality of filaments for oral care appliances such as manual and electric toothbrushes are well known in the art. Generally, the bristle tufts are attached to a bristle carrier of a head intended to be inserted into a user's oral cavity. Usually, a gripping handle is attached to the head, and this handle is grasped by the user during toothbrushing. The head is either permanently connected to the handle or repeatedly detachable from the handle.

[0003] To effectively clean teeth, an appropriate contact pressure must be applied between the free end of the filament and the teeth. Generally, the contact pressure depends on the bending stiffness and displacement of the filament. On the other hand, the bending stiffness of a single filament depends on its length and cross-sectional area. Usually, a longer filament exhibits a lower bending stiffness compared to a shorter filament. However, relatively thin filaments tend to bend and separate easily, and the relatively low bending stiffness reduces the efficiency of plaque removal on the tooth surface. In addition, it deteriorates the interdental penetration characteristics and cleaning performance. To compensate for the decrease in the bending stiffness of longer filaments, the size of the cross-sectional area of the filament can be increased. However, relatively thick filaments may cause an uncomfortable brushing sensation and are particularly likely to damage the gums in the oral cavity, especially when using an electric toothbrush. In addition, thicker filaments may exhibit low bending recovery and may give the impression of wear of the tuft pattern due to the use of the filaments after a relatively short period of use.

[0004] Furthermore, filaments having a contour along their length extension that results in a non-circular cross-sectional area, such as a polygonal or cross-shaped cross-sectional area, are also well-known in the art. Such filaments should improve the cleaning characteristics of oral care appliances during normal use. In particular, the contoured edges should provide a more robust frictional action during the brushing process to improve the removal of plaque and other residues on the tooth surface.

[0005] Toothbrushes with conventional types of tufts are suitable for properly cleaning the buccal surfaces outside the teeth, but they are generally not equally suitable for the proper removal of dental plaque and debris from the interdental areas between adjacent teeth and other hard-to-reach oral areas because penetration into the interdental spaces remains relatively difficult. In particular, they are usually not well-suited for adequately cleaning the gingival margins where dental plaque begins to grow. Therefore, in order to achieve and maintain good oral health and to prevent gingivitis, it is important to clean along the gingival line, and in particular, to clean the gap between the tooth and the periodontal tissue, the so-called gingival sulcus. The lack of good removal of dental plaque in the gingival sulcus is known to cause gingivitis, i.e., inflammation of the gingival tissue. Note that standard tufts do not provide sufficient capillary action to remove dental plaque and debris from the tooth and gingival surfaces during brushing. However, in order to obtain good cleaning results, the tuft / filament must reach the dental plaque, then break down the dental plaque, and finally remove the dental plaque. Furthermore, the tuft should provide a good tactile feel to the gingiva during brushing, especially when an electric / electrically driven toothbrush that performs rotational and / or vibrational movements is used.

[0006] During the brushing process, the mechanical stress generated within the cross-shaped filaments results in a stronger stress at the tip of the cross-shaped filaments compared to circular-shaped filaments. This means that in tufts with similar overall stiffness, the cross-shaped filaments must withstand a higher maximum stress value compared to circular-shaped filaments. This increased stress in individual cross-shaped filaments can lead to an increased wear behavior during use. This wear is characterized by an increased spread outside the tuft and reduces consumer acceptance. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] The object of the present disclosure is to provide a cleaning part for an electric oral hygiene device that overcomes at least one of the above-mentioned drawbacks. Another object of the present disclosure is to provide an electric oral hygiene device provided with such a cleaning part.

Means for Solving the Problems

[0008] According to one aspect, there is provided a cleaning part for an electric oral hygiene device, the cleaning part comprising a carrier attached for driven rotation and / or oscillating rotation around a rotation axis, and at least a plurality of first cleaning elements and a plurality of second cleaning elements, the cleaning elements being attached to the attachment surface of the carrier, the carrier having an outer edge and an inner part, the plurality of first cleaning elements being arranged at the inner part of the carrier, the plurality of second cleaning elements being arranged at the outer edge of the carrier, each of the plurality of first cleaning elements having a longitudinal axis and a substantially cross-shaped cross-sectional area extending in a plane substantially perpendicular to the longitudinal axis, the cross-shaped cross-sectional area having four protrusions and four channels, the protrusions and the channels being arranged alternately.

[0009] According to one aspect, there is provided an electric oral hygiene device, the device comprising such a cleaning part and a handle, the cleaning part being repeatedly detachable from the handle.

Brief Description of the Drawings

[0010] The present invention will be described in more detail below with reference to various embodiments and drawings.

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DETAILED DESCRIPTION OF THE INVENTION

[0011] The electric oral hygiene device (also referred to as an "oral care instrument") according to the present disclosure may be an electric toothbrush having a handle and a cleaning part. Such a cleaning part is also referred to as a "head". The cleaning part extends from the handle and is repeatedly detachable from the handle.

[0012] The cleaning part may include a carrier / brush carrier that may have a substantially circular or oval shape. The carrier has an outer edge and an inner part. Such a carrier can be provided for an electric toothbrush that can perform a rotational vibration motion. The brush carrier of the electric toothbrush can be driven to move axially in a manner that rotates around the axis of motion and vibrates along the axis of motion, and such an axis of motion may extend substantially perpendicular to the plane defined by the upper surface on the upper side of the brush carrier.

[0013] At least a plurality of first cleaning elements and a plurality of second cleaning elements are attached to the attachment surface of the carrier. While a plurality of first cleaning elements are arranged / attached to the inner part of the carrier, a plurality of second cleaning elements are arranged / attached to the outer edge of the carrier, that is, in the vicinity of the outer edge.

[0014] Each of the plurality of first cleaning elements has a longitudinal axis and a substantially cross-shaped cross-sectional area extending in a plane substantially perpendicular to this longitudinal axis. The longitudinal axis of the cleaning element is defined by the main extension of the cleaning element. The cross-shaped cross-sectional area of the first cleaning element has four protrusions and four channels, and the protrusions and channels are arranged alternately.

[0015] The first cleaning element may be an elastomeric element or a filament. Such filaments may be made from a thermoplastic polymer, such as polybutylene terephthalate (PBT). A plurality of such first cleaning elements / filaments may be bundled together to form a tuft of filaments attached to a carrier. Such a tuft of first cleaning elements / filaments may be referred to as a "first type of tuft". Optionally, such a first type of tuft may include not only the first cleaning elements but also a mixture of the first cleaning elements and some other types of cleaning elements / filaments. For example, a number of first cleaning elements / filaments and a number of circular and / or trefoil filaments may be bundled together to form a first type of tuft.

[0016] The second cleaning element disposed at the outer edge of the carrier has a longitudinal axis and a substantial cross-sectional area extending in a plane substantially perpendicular to the longitudinal axis. The cross-sectional area of the second cleaning element is different from the cross-sectional area of the first cleaning element. For example, the cross-sectional area of the second cleaning element may be substantially circular, trefoil, or may have a shape including a plurality of depressions. Such a second cleaning element may be an elastomeric element or may be filaments bundled together to form a tuft of filaments. Such a tuft of second cleaning elements / filaments may sometimes be referred to as a "second type of tuft".

[0017] Such an arrangement of the first and second cleaning elements provides an excellent brushing / washing effect. The first cleaning element disposed inside the carrier can provide a deep cleaning effect by the protrusions scraping against the teeth, thereby removing dental plaque and other residues on the tooth surface. However, the second cleaning element disposed at the outer edge can provide a gentler cleaning action along the more sensitive gum line. Also, the protrusions of the first cleaning element can penetrate more easily into the interdental areas and hard-to-reach areas during the rotational and vibrational movement of the head, which can give further improved cleaning characteristics. The dental plaque and other residues are loosened by the vibrational action of the first cleaning element, while the dental plaque and further residues can be removed by the rotational movement.

[0018] Since the first cleaning element is disposed on the inner portion of the carrier, it has less rotation and movement during the brushing operation compared to the second cleaning element disposed on the outer edge. This has the advantage that the first cleaning element bends and curves less during use. Thus, during the brushing process, the mechanical stress generated within the cross-shaped filaments results in stronger stress at the tips of the cross-shaped filaments (compared to circular-shaped filaments), but this is reduced. The wear of the cross-shaped filaments during use can be significantly reduced. This wear is typically characterized by an increase in the spread of the tufts, which reduces consumer acceptance. Also, thinner cleaning elements can be applied to create a more comfortable brushing sensation / experience. When such thin filaments are disposed on the inner portion of the carrier, such elements create the impression of less wear. For example, each of the first cleaning elements may have a cross-sectional area with an outer diameter, and the outer diameter of at least some of the first cleaning elements may be from about 0.1 mm to about 0.3 mm, or about 0.256 mm. Surprisingly, it has been found that cross-shaped filaments having a diameter of about 0.256 mm provide an improved brushing sensation compared to cross-shaped filaments having a larger diameter.

[0019] In the context of the present disclosure, the outer diameter of the first cleaning element is defined by the length of a straight line passing through the center of the cross-sectional area of the element, and its endpoints are located on the outermost circumference of the cross-sectional area. In other words, the cross-shaped cross-sectional area has a virtual outer circumference (i.e., an outer circumscribing circle) in the shape of a circle, and the outer diameter is defined as the longest straight-line segment of the circle passing through the center of the circle.

[0020] The cross-shaped filaments of the first type of tuft may have a relatively low packing ratio within the range of about 45% to about 57%, or within the range of about 45% to about 55%, or within the range of about 48% to about 50%. In the context of the present disclosure, the term "packing ratio" is defined as the total cross-sectional area of the filaments in the tuft pore divided by the cross-sectional area of the tuft pore. In embodiments where fixtures such as staples are used to attach the tuft within the tuft pore, the fixing means area is excluded from the cross-sectional area of the tuft pore.

[0021] While the cross-sectional shape filaments still have contact with each other along a part of the outer lateral surface, a packing ratio of about 45% to about 57%, or about 45% to about 55%, or about 48% to about 50% maintains a specific interstitial volume within the tuft. The interstitial volume can deliver more dentifrice to the brushing process, allowing the dentifrice to interact with the teeth for a longer time and contributing to an improved brushing effect. In addition, the interstitial volume, i.e., the voids between the filaments, allows for an increased uptake of loosened dental plaque due to improved capillary action. In other words, such a low packing ratio results in more dentifrice / dentifrice being retained on / attached to the filaments for a longer time during the brushing process. Furthermore, a lower tuft density may avoid the possibility that the dentifrice diffuses and results in an improved overall brushing process. When cleaning in contact with the teeth, the dentifrice is better received and directly delivered in the channels, thereby achieving a greater polishing effect, which is desirable especially with respect to the removal of tooth discoloration.

[0022] In other words, a relatively low packing ratio within the range of about 45% to about 57%, or about 45% to about 55%, or about 48% to 50% can provide an improved brushing effect, i.e., better removal of dental plaque and debris from the tooth surface and gum line, due to the improved capillary effect. These capillary effects allow the dentifrice to flow towards the tips / free ends of the filaments, and thus the dentifrice can be more effectively applied to the teeth and gum line during brushing. At the same time, the uptake of dental plaque and debris from the surfaces of the teeth and gum line is improved.

[0023] Note that due to the cross-shaped configuration of the filaments, each individual filament is stiffer than a filament having a circular configuration when manufactured from the same amount of material. However, due to the low packing rate within the range of about 45% to about 57%, or about 45% to about 55%, or about 48% to 50%, the overall stiffness of the tuft manufactured from the cross-shaped filaments is reduced compared to the tuft of circular filaments. Surprisingly, it has been found that such tufts provide an improved cleaning efficiency while providing an improved sensory experience, i.e., a softer feel in the oral cavity during brushing. The projections of the cross-shaped filaments can easily access the gingival sulcus and other difficult-to-reach areas, such as the tooth surfaces between adjacent teeth, scrape over the surface to dislodge plaque, and due to the improved capillary effect of the overall tuft, the plaque can be removed better. Due to the special configuration, the cross-shaped filaments can penetrate deeply into the gingival sulcus and the adjacent interdental areas. Note that the relatively low packing rate of the first type of tuft allows the individual cross-shaped filaments to better conform to the contours of the gingival line and the gingival sulcus.

[0024] Since at least one second type of tooth cleaning element is disposed at the outer edge of the carrier / head, i.e., the outer edge of the bristle area, the aforementioned second tooth cleaning element can provide the first type of tuft with improved stability to prevent a wide spread of the first type of tuft. Thus, the second tooth cleaning element can significantly improve the wear behavior and wear appearance of the first type of tuft, which has a relatively low packing rate and thus low stability while providing improved tooth cleaning efficiency. In particular, over a long period of time, a brush that appears to have been used very little after brushing provides higher consumer acceptance.

[0025] The second cleaning element may be filaments grouped together to form at least one tuft of a second type, and may have a higher bending stiffness / stability than the tufts including the first cleaning element. The aforementioned tufts of the second type may have a packing density of about 70% to about 80%, thereby providing a higher bending stiffness and stability of the whole tuft compared to the tufts of the first type. When the second tooth cleaning element is an elastomeric element, it may be made of a TPE material and / or may have the shape of an elastomeric wall extending along the length extension of the head. Such an elastomeric wall may provide a polishing effect on the outer surface of the teeth and may more completely remove tooth discoloration. Alternatively, the elastomeric element may have the shape of rubber knobs or rubber fingers for stimulating and massaging the tooth roots.

[0026] At least some of the first cleaning elements may be at least partially arranged in a circle around the axis of rotation.

[0027] Furthermore, at least some of the second cleaning elements may be at least partially arranged in a circle around the axis of rotation along the outer edge of the carrier. Such a carrier / head configuration may further enhance the effects and advantages as described above.

[0028] At least some of the first cleaning elements may be circumferentially inclined in the same circumferential direction with respect to the axis of rotation so as to improve the interdental penetration of the cleaning elements and thus the toothbrushing / cleaning effect. Furthermore, at least some of the first cleaning elements may be arranged at the center of the carrier.

[0029] At least some of the first cleaning elements and some of the second cleaning elements may be arranged alternately in the circumferential direction with respect to the axis of rotation.

[0030] Each channel of the cross-shaped first cleaning element may have a concave curvature formed by adjacent converging protrusions. The aforementioned concave curvature may have a radius within the range of about 0.02 mm to about 0.09 mm, or about 0.03 mm to about 0.06 mm. In other words, two adjacent protrusions, i.e., two adjacent lateral transverse edges of the protrusion, may converge at the bottom of the channel and may define a "convergence region". The adjacent protrusions may converge in the aforementioned convergence region in a concave curvature pattern, i.e., in a pattern in which a radius curved inward is formed at the bottom of the channel. The radius within such a range is relatively large compared to a standard cross-shaped filament.

[0031] In the past, it has been observed that conventional cross-shaped filaments have the drawback that these types of filaments may easily become entangled with each other both during manufacturing and during toothbrushing. However, surprisingly, during the so-called "picking process", when multiple filaments are twisted together to form a single tuft, the possibility of the filaments / cleaning elements becoming entangled is significantly reduced. Therefore, it has been found that the specific shape / contour of the outer surface of the first cleaning element according to the present disclosure enables improved manufacturability.

[0032] Furthermore, due to the relatively large radius at the bottom of the channel, the stability of the filament / first cleaning element is increased. Therefore, for example, during stapling or a high-temperature tufting process, when the filament is pushed and fixed onto the mounting surface of the brush head, the damage to the filament occurring during the manufacturing process of the brush is reduced. In the past, it has been observed that a relatively large number of conventional cross-shaped filaments are damaged during the picking process. In particular, the protrusions may be cut off and separated from the filament, or the filaments may be twisted together in the confluence region at the bottom of the channel. The twisted filaments may provide relatively sharp edges, which may damage / hurt oral tissues during toothbrushing.

[0033] Furthermore, surprisingly, due to the specific shape of the radius of the concave curvature, when the gap between two adjacent filaments can be maximized, it has been found that the filaments within the tuft can be better filled within a relatively low packing rate, i.e., in the range of about 45% to about 57%, or about 45% to about 55%, or about 48% to about 50%. It has been found that it is important for the filaments to maintain a gap in a specific void region while still having contact with each other. In order to manufacture a toothbrush that is evaluated by consumers with respect to the overall appearance in accordance with the specified requirements, typically, a high packing rate (about 70% to about 80% for circular filaments, about 80% for diamond-shaped filaments, about 89% for trilobal filaments) is required. For a toothbrush manufactured by the stapling process, a packing rate higher than about 70% will result in filaments that are insufficiently compressed within the tuft holes, and thus the tuft retention will be insufficient. Therefore, when circular filaments have a packing rate lower than about 70%, the specified requirements are not met. For a toothbrush tufted at a high temperature, a packing rate lower than about 70% can allow the plastic melt to enter into the tuft during the molding process when the pressure of the melt pushes the filaments of the tuft to the other side until the filaments contact each other. So-called multi-spines are thereby formed, which may hurt / damage the gum, and thus the product becomes unsafe. In addition to the regulatory and safety perspectives, a low-packed tuft of circular filaments can have a "rough" and broken appearance and may not be acceptable to consumers. However, by using cross-shaped filaments having a radius in the range of about 0.02 mm to about 0.09 mm of the concave curvature of the channel, a low packing rate can be achieved for a product that provides improved cleaning characteristics while having an acceptable overall appearance, meeting the regulations, and being safe.

[0034] Each protrusion of the cross-shaped cross-sectional area has two outer lateral edges along the longitudinal extension of the filament. These outer edges can generate relatively high concentrated stresses on the tooth surface to break and remove dental plaque. The outer edges can provide a frictional effect so that dental plaque and other debris can be more effectively loosened. Due to the relatively large radius of the concave curvature at the bottom of the channel, protrusions with increased rigidity / stability are provided that can more easily / effectively loosen / remove dental plaque from the tooth surface. The channel can then capture the broken dental plaque and remove it from the tooth.

[0035] Surprisingly, it has been found that such a filament shape provides even further improved cleaning performance while maintaining the comfort of the brush in the oral cavity. In addition, such a shape has been found to further help reduce wear of the appearance of the filaments / tufts as the filaments are even less likely to become entangled during brushing. Furthermore, the manufacturability of such filaments during the toothbrush manufacturing process is further improved.

[0036] Each protrusion of the cross-shaped cross-sectional area of the first cleaning element may have a distal end with a rounded tip, thereby forming a curvature with a specific radius. The radius of curvature of the protrusion may be from about 0.01 mm to about 0.02 mm, or about 0.015 mm.

[0037] The ratio of the radius of curvature of the protrusion to the radius of curvature of the channel may be in the range of about 0.1 to about 1.0 or about 0.2 to about 0.5. This ratio is relatively small compared to the standard cross-shaped filaments according to the prior art. In other words, with respect to the diameter of the curvature of the protrusion, i.e., with respect to the width extension portion of the protrusion, the radius of the concave curvature of the channel is relatively large, or in other words, the diameter of the curvature of the protrusion may be relatively thin compared to the radius of the concave curvature of the channel. For example, each protrusion of the first cleaning element may have a maximum thickness, and the maximum thickness of each protrusion may be about 0.025 mm to about 0.045 mm, or about 0.037 to about 0.041 mm. The relatively large radius provides relatively thin protrusions with increased stability. Thus, during the manufacturing process of the brush, especially when the filaments are punched, the filaments / protrusions are less likely to be damaged, or the relatively thin protrusions are less likely to break off. In other words, the manufacturability of such filaments during the manufacturing process of the toothbrush is further improved.

[0038] Furthermore, surprisingly, it has been found that such a filament shape provides even further improved cleaning performance while maintaining the comfort of the brush in the oral cavity. In addition, it has been found that such a shape further promotes a reduction in the wear of the appearance of the filaments / tufts, as the likelihood of the filaments becoming entangled during brushing is further reduced.

[0039] The diameter of the curvature of the protrusion may be in the range of about 5% to about 12% of the outer diameter of the filament. Surprisingly, it has been found that such filaments can better conform to the tooth contour, penetrate more easily into the interdental spaces, and remove plaque and debris more completely.

[0040] The protrusions of the first cleaning element in a cross shape may taper radially in an outward direction, i.e., away from the center of the cross-sectional area and towards the outer circumference. Such tapered protrusions can further ensure access to narrow gaps and other hard-to-reach areas, enabling penetration / entry into deeper and more effective interdental areas. Compared with circular filaments made from the same amount of material, the higher bending rigidity of the cross-shaped filaments / cleaning elements strengthens the protrusions of the filaments, allowing them to slide more easily into the interdental areas.

[0041] The protrusions can taper radially outward at an angle within the range of about 6° to about 25°, or at an angle within the range of about 8° to about 20°. Surprisingly, it has been found that such tapering enables optimal interdental penetration characteristics. Further, such filaments can be more easily bundled into tufts without getting entangled on the contours of adjacent filaments.

[0042] The first cleaning element / filament may be a substantially cylindrical cleaning element / filament, i.e., the filament may have a substantially cylindrical outer lateral surface. In other words, the shape and size of the cross-sectional area of the filament along its longitudinal axis may not substantially change, i.e., the shape and size of the cross-sectional area may be substantially constant over the longitudinal extent of the filament. In the context of the present disclosure, the term "outer lateral surface of the filament" means the outer surface or outer side surface of the filament on its side. This type of filament can provide increased bending rigidity compared to tapered filaments. The higher bending rigidity can further facilitate the penetration of the filament into the interdental gaps / spaces. Further, cylindrical filaments generally wear out slowly and can provide a longer service life of the filaments.

[0043] The cylindrical filament may have a substantially rounded tip / free end and provide gentle cleaning characteristics. The rounded tip can prevent the gingiva from being damaged during brushing. In the context of the present disclosure, a filament with a rounded end may still fall within the definition of a substantially cylindrical filament.

[0044] Alternatively, the first cleaning element / filament may comprise a substantially cylindrical portion and a tapered portion along its longitudinal axis, the tapered portion tapering longitudinally towards the free end of the filament, and the cylindrical portion having a cross-sectional area according to the present disclosure. In other words, the filaments of the first type of tuft may be tapered filaments having a pointed tip. The tapered filaments can optimally penetrate into the area between two teeth and into the periodontal pocket during brushing, and thus may provide improved cleaning characteristics. The tapered filaments may have an overall length extending on the mounting surface of the head within a range of about 8 mm to about 16 mm, optionally about 12.5 mm, and a tapered portion within a range of about 5 mm to about 10 mm measured from the tip of the filament. The pointed tip may be needle-shaped or may have a branched or feathery end. The tapered portion can be manufactured by chemical and / or mechanical tapering processes.

[0045] The first and / or second cleaning elements may be made from polyamide, such as nylon, with or without an abrasive such as kaolin clay, polybutylene terephthalate (PBT) with or without an abrasive such as kaolin clay, and / or a polyamide indicator material, such as a nylon indicator material, colored on the outer surface. The coloring of the polyamide indicator material can gradually wear away as the filament is used over time, indicating the degree to which the filament has worn.

[0046] The first and / or second cleaning element may comprise at least two sections of different materials. At least one section may comprise a thermoplastic elastomer material (TPE), and at least one section may comprise a polyamide, with or without an abrasive such as kaolin clay, e.g., nylon, a polybutylene terephthalate (PBT) with or without an abrasive such as kaolin clay, or a polyamide indicator material, e.g., a nylon indicator material, colored on the outer surface. These at least two sections may be arranged in a parallel structure or in a core-sheath structure, which may result in a reduction in the rigidity of the entire filament. A core-sheath structure with an inner / core section comprising a harder material, e.g., polyamide or PBT, and an outer / sheath section surrounding the core section and comprising a softer material, e.g., TPE, may provide a filament with a relatively soft outer lateral surface that may result in gentle cleaning properties.

[0047] The first and / or second cleaning element may comprise components selected from fluoride, zinc, strontium salts, flavorants, silica, pyrophosphates, hydrogen peroxide, potassium nitrate, or combinations thereof. For example, fluoride may provide a mineralizing effect and thus may prevent tooth decay. Zinc may strengthen the user's immune system. Hydrogen peroxide may bleach / whiten teeth. Silica may have an abrasive effect to more effectively remove dental plaque and debris from teeth. Pyrophosphates may inhibit the formation of new plaque, tartar, and dental calculus along the gum line. A cleaning element / filament containing pyrophosphates may provide continuous protection against gum and oral mucosa inflammation.

[0048] When a plurality of such filaments are bundled together to form a tuft, they may be arranged in such a way that the filaments on the outer lateral surface of the tuft contain pyrophosphates and may inhibit the formation of plaque, tartar, and dental calculus along the gum line, while the filaments arranged in the center of the tuft contain fluoride and may mineralize teeth during the brushing process.

[0049] At least one of the above-described components may be coated on the exterior, i.e., on the outer section of the filament. In other words, the first and / or second cleaning elements / filaments of at least some of the tufts of bristles may have a core-sheath structure where the inner / core section may comprise TPE, polyamide, or PBT, and the outer / sheath section may comprise at least one of the above-described components. Such a core-sheath structure can enable the component(s) to be effective on the teeth at a relatively high concentration, i.e., during toothbrushing, the component(s) can come into direct contact with the teeth.

[0050] Alternatively, at least one of the above-described components may be co-extruded with TPE, polyamide such as nylon, and / or PBT. Such an embodiment can enable the component(s) to gradually become effective on the teeth when the filament material slowly wears away during use.

[0051] The head for an oral care instrument according to the present disclosure may comprise a bristle carrier having tuft holes, such as blind-ended holes. The tufts according to the present disclosure may be fixed / tethered to the aforementioned tuft holes by a stapling process / fixed tufting method. This means that the filaments of the tuft are bent / folded in a substantially U-shaped manner around a fixture, such as a metal fixing wire or a fixing plate. The filament together with the fixture is pushed into the tuft hole, whereby the fixture penetrates into the wall on the opposite side of the tuft hole, thereby tethering / fixing / securing the filament to the bristle carrier. The fixture may be fixed to the opposite wall by positive engagement and frictional engagement. When the tuft hole is a blind-ended hole, the fixture holds the filament against the bottom of the hole. In other words, the fixture may be positioned across the U-shaped bend in a substantially vertical manner. Since the filaments of the tuft curve around the fixture in a substantially U-shaped configuration, the first rim and the second rim of each filament extend from the bristle carrier in the direction of the filament. The type of filament that may be used in the stapling process / suitable for use in the stapling process is also referred to as a "both-end filament". The head for an oral care instrument manufactured by the stapling process can be provided in a relatively low-cost and time-efficient manner. Due to the improved shape of the filaments of at least one first type of tuft according to the present disclosure, during the stapling process, when the filaments are protruded and fixed on the attachment surface of the brush head, for example, cut, only a small number of filaments are damaged. Further, when a plurality of filaments are protruded to form one tuft, only a small number of filaments are entangled on the outer surface of the adjacent filaments.

[0052] Alternatively, the tufts may be attached / fixed to the head by means of a high-temperature tufting process. One method of manufacturing the head of an oral care appliance may include the following steps. First, tufts may be formed by providing a desired amount of filaments according to the present disclosure. Second, the tufts may be positioned within the die cavity such that the ends of the filaments to be attached to the carrier extend into the cavity. Third, the carrier is formed around the ends of the filaments extending into the die cavity by an injection molding process, whereby the tufts can be fixed within the carrier. Prior to initiating the injection molding process, the ends of at least one tuft extending into the die cavity may optionally be melted / fused together to form a molten mass or molten spheres and joined together with the filaments, whereby the molten mass or molten spheres may be disposed within the cavity. The tufts may be held within the die cavity by a die post having blind holes corresponding to the desired positions of the tufts on the finished head of the oral care appliance. In other words, the filaments of the tufts attached to the carrier by means of a high-temperature tufting process need not overlap at an intermediate portion along their length and need not be attached to the head by using fixtures / staples. The tufts may be attached onto the carrier by means of a fixtureless tufting process. The high-temperature tufting manufacturing process allows for complex tuft shapes. For example, the tufts may have a specific topography / shape at their free ends, i.e., on their upper surfaces, and may be shaped to optimally conform to the tooth contour and may also be shaped to further enhance the penetration between teeth. For example, the topography may be angled or rounded in one or two directions, may have a pointed tip, or may be formed linearly, concavely or convexly. Due to the improved shape of the filaments / first cleaning elements according to the present disclosure, during the high-temperature tufting process, when the filaments are pushed and fixed onto the attachment surface of the brush head, for example, by cutting, the filaments are less likely to be damaged. Further, when multiple filaments are pushed to form one tuft, fewer filaments become entangled on the outer surfaces of adjacent filaments.

[0053] The following is a non - limiting discussion of exemplary embodiments of an oral hygiene device and its components according to the present disclosure with reference to the drawings.

[0054] Figure 1 shows a schematic perspective view of an exemplary embodiment of an electric oral hygiene device 10. In this example, the electric oral hygiene device 10 is an electric toothbrush comprising a handle 12 and a cleaning part 14. The cleaning part 14 comprises a toothbrush head or bristle carrier 16 and a shaft 18 that is repeatedly detachable from the handle 12.

[0055] As shown in Figure 2, the carrier 16 of the cleaning part 14 is attached to the head 20 so as to rotate passively and / or swing - rotate about a rotation axis 22. As can be derived from the exemplary embodiment according to Figures 2 - 6, at least a plurality of first cleaning elements 24 and a plurality of second cleaning elements 26 are attached to the attachment surface 28 of the carrier 16. The carrier 16 has an outer edge 30 and an inner part 32. While a plurality of first cleaning elements 24 are arranged in the inner part 32 of the carrier 16, a plurality of second cleaning elements 26 are arranged at the outer edge 30 of the carrier 16. The first and / or second cleaning elements 24, 26 can be filaments bundled in a tuft shape or elastomeric cleaning elements. The first and / or second cleaning elements may be made of a thermoplastic polymer, such as polybutylene terephthalate (PBT).

[0056] As shown in Figure 7, the first cleaning element 24 has a substantially cross - shaped cross - sectional area 34 that extends in a longitudinal axis and in a plane substantially perpendicular to the longitudinal axis. The cross - shaped cross - sectional area 34 has four protrusions 36 and four channels 38, and the protrusions 36 and channels 38 are arranged alternately. Similarly, each of the second cleaning elements 26 has a longitudinal axis. However, the cross - sectional area extending in a plane substantially perpendicular to the longitudinal axis may be, for example, circular.

[0057] The cross - sectional area 34 of the first cleaning element 24 has an outer diameter 40, and the outer diameter of at least some of the first cleaning elements can be from about 0.1 mm to about 0.3 mm, or about 0.256 mm.

[0058] Each protrusion 36 of the first cleaning element 24 has a maximum thickness 42, and the maximum thickness 42 of each protrusion may be from about 0.025 mm to about 0.045 mm, or from about 0.037 to about 0.041 mm. Further, each protrusion 36 of the first cleaning element 24 has a distal end 48. The aforementioned distal end 48 can have its end rounded, thereby forming a curvature 50 having a radius 52 of from about 0.01 mm to about 0.02 mm, or about 0.015 mm.

[0059] Each channel 38 of the first cleaning element 24 has a concave curvature 44 formed by adjacent and converging protrusions 36. The aforementioned concave curvature 44 may have a radius 46 within the range of from about 0.02 mm to about 0.09 mm, or from about 0.03 mm to about 0.06 mm.

[0060] Using such a shape of the first cleaning element 24, a plurality of such first cleaning elements 24 can be bundled together to form a tuft 54 of cleaning elements / filaments 24. The tuft 54 may have a packing ratio within the range of from about 45% to about 57%, or from about 45% to about 55%, or from about 48% to about 50%.

[0061] As shown in FIGS. 2 to 5, at least some of the first cleaning elements 24 bundled into the first type of tuft 54 can be at least partially disposed on a circle around the rotation axis 22. Further, at least some of the first cleaning elements 24 bundled into the first type of tuft 54 can be disposed at the center 58 of the carrier 16 (see FIGS. 5 and 6).

[0062] Further, as shown in FIG. 2, at least some of the first cleaning elements 24 bundled into the first type of tuft 54 can be circumferentially inclined in the same circumferential direction with respect to the rotation axis 22.

[0063] As shown in FIGS. 2 to 6, at least some of the second cleaning elements 26 bundled into the second type of tuft 56 can be at least partially disposed on a circle around the rotation axis 22 along the outer edge 30 of the carrier 16.

[0064] As shown in FIG. 2, the first type of hair bundle 54 and the second type of hair bundle 56 can also be alternately arranged in the circumferential direction with respect to the rotation axis 22.

[0065] In the context of the present disclosure, the term "substantially" means a configuration of an element or mechanism that, while expected to exhibit theoretically exact coincidence or behavior, may in practice be embodied as slightly inexact. As such, the term indicates the degree to which a quantitative value, measurement, or other related expression may vary from the recited standard without causing a change in the basic function of the object in question.

[0066] The dimensions and values disclosed herein should not be understood as being strictly limited to the recited exact numerical values. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as "40 mm" is intended to mean "about 40 mm".

Claims

1. A cleaning part (14) for an electric oral hygiene device (10), wherein the cleaning part (14) comprises: a carrier (16) mounted for driven rotation and / or oscillatory rotation about a rotation axis (22); and at least a plurality of first cleaning elements (24) and a plurality of second cleaning elements (26), which are mounted on a mounting surface (28) of the carrier (16), and the carrier (16) has an outer edge (30) and an inner part (32), the plurality of first cleaning elements (24) and the plurality of second cleaning elements (26). The plurality of first cleaning elements (24) are arranged on the inner part (32) of the carrier (16), the plurality of second cleaning elements (26) are arranged on the outer edge (30) of the carrier (16), and each of the plurality of first cleaning elements (24) has a longitudinal axis and a substantially cross-shaped cross-sectional area (34) extending in a plane substantially perpendicular to the longitudinal axis. The cross-shaped cross-sectional area (34) has four protrusions (36) and four channels (38), and the protrusions (36) and the channels (38) are arranged alternately. The cleaning part (14).

2. Each of the second cleaning elements (26) has a longitudinal axis and a cross-sectional area extending in a plane substantially perpendicular to the longitudinal axis, and the cross-sectional area is different from the cross-sectional area of the first cleaning element, preferably substantially circular, trifoliate, or a shape having a plurality of depressions. The cleaning part (14) according to claim 1.

3. The first and / or second cleaning elements (24, 26) are filaments arranged in tufts (54, 56) or elastomeric cleaning elements. The cleaning part (14) according to claim 1 or 2.

4. The first cleaning element (24) is a filament arranged in a tuft (54) having a filling rate in the range of about 45% to about 57%, preferably about 45% to about 55%, more preferably about 48% to about 50%. The cleaning part (14) according to any one of claims 1 to 3.

5. At least some of the first cleaning elements (24) are at least partially arranged on a circle around the rotation axis (22). The cleaning part (14) according to any one of claims 1 to 4.

6. The cleaning part (14) according to any one of claims 1 to 5, wherein at least some of the first cleaning elements (24) are circumferentially inclined in the same circumferential direction with respect to the rotation axis (22).

7. The cleaning part (14) according to any one of claims 1 to 6, wherein at least some of the second cleaning elements (26) are at least partially arranged on a circle around the rotation axis (22) along the outer edge (30) of the carrier (14).

8. The cleaning part (14) according to any one of claims 1 to 7, wherein at least some of the first cleaning elements (24) are arranged at the center (58) of the carrier (16).

9. The cleaning part (14) according to any one of claims 1 to 8, wherein at least some of the first cleaning elements (24) and some of the second cleaning elements (26) are arranged alternately in the circumferential direction with respect to the rotation axis (22).

10. Each of the first cleaning elements (24) has a cross-sectional area (34) with an outer diameter (40), and the outer diameter (40) of at least some of the first cleaning elements (24) is from about 0.1 mm to about 0.3 mm, preferably about 0.256 mm. The cleaning part (14) according to any one of claims 1 to 9.

11. Each protrusion (36) of the first cleaning element (24) has a maximum thickness (42), and the maximum thickness (42) of each protrusion (36) is from about 0.025 mm to about 0.045 mm, preferably from about 0.037 to about 0.041 mm. The cleaning part (14) according to any one of claims 1 to 10.

12. Each channel (38) of the first cleaning element (24) has a concave curvature (44) formed by being adjacent to and converging on the protrusion (36), the concave curvature (44) has a radius (46), and the radius (46) of the concave curvature (44) of the channel (38) is in the range of about 0.02 mm to about 0.09 mm, preferably about 0.03 mm to about 0.06 mm. The cleaning part (14) according to any one of claims 1 to 11.

13. At least some of the respective protrusions (36) of the first cleaning element (24) have a distal end (48), and the distal end (48) is rounded at its end so as to form a curved portion (50) having a radius (52) of from about 0.01 mm to about 0.02 mm, preferably about 0.015 mm. The cleaning unit (14) according to any one of claims 1 to 12.

14. At least some of the first cleaning elements (24) are made of a thermoplastic polymer, preferably polybutylene terephthalate (PBT). The cleaning unit (14) according to any one of claims 1 to 13.

15. An electric oral hygiene device (10) comprising a handle (12) and a cleaning unit (14) according to any one of claims 1 to 14, wherein the cleaning unit (14) is repeatedly detachable from the handle (12).

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