FIELD OF THE INVENTION
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The present invention relates to a guard tooth for a guard blade of a hair cutting device, a corresponding guard blade, a cutter tooth for a cutter blade of a hair cutting device, a corresponding cutter blade and a corresponding hair cutting device.
BACKGROUND OF THE INVENTION
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In the field of cutting and grooming hair, cutter blades are often used having a plurality of cutter teeth for cutting hair usually via a reciprocal movement of the cutter teeth. The cutter blade captures hair to be cut between adjacent teeth when the cutter blade is moved along a user's skin and sharp edges provided at the cutter teeth shear off or cut the hair via the reciprocal sawing movement perpendicular to the movement of the cutter blade along the skin. Since the sharp cutter teeth are to be brought in the vicinity of a user's skin for haircutting, they must be usually shielded by respective guarding elements for protecting the skin from a direct contact with the sharp cutter teeth. Various guard elements are known in the art, which attempt to space apart the cutter teeth from the skin. However, known guard elements are often bulky and may accordingly adversely impact the hair cut efficiency. Furthermore, the known guard elements may provide only inadequate skin protection and may harm the skin during the haircutting process. That is, users often experience undesirable skin irritation and discomfort during hair cutting, for instance due to suboptimal design of the guard elements.
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Thus, it is an object of the present invention to provide an improved configuration, which addresses the above noted drawbacks of the prior art.
SUMMARY OF THE INVENTION
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The above noted problems are at least partially solved or alleviated by the subject matter of the independent claims of the present disclosure, wherein further preferred embodiments are expressed by the dependent claims.
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The present invention relates to a guard tooth for a guard blade of a hair cutting device, the guard tooth extending in a lateral direction from the guard blade and comprising: a first guard tooth portion connectable to a guard blade base portion, and a second guard tooth portion extending from the first guard tooth portion in the lateral direction, wherein the first guard tooth portion comprises a cutter blade running surface adapted to face a cutter blade arrangeable above the guard blade for at least partially contacting the cutter blade running surface with a cutter blade contact surface, wherein the second guard tooth portion comprises an elevated portion extending in the lateral direction from the cutter blade running surface and in a height direction perpendicular to the lateral direction, wherein a first angle between a first tangent line of a cutter blade top surface opposite to the cutter blade contact surface, representing the slope of the cutter blade top surface, and a second tangent line between an elevated portion top surface and the cutter blade top surface is smaller than 5°.
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Thus, improved protection from skin damages and reduced skin irritation may be achieved, while hair cutting efficiency may be enhanced.
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The guard tooth according to the present invention in particular overcomes the problem of disadvantageous skin deflection during haircutting operation, which may also be referred to as skin bulging. Skin bulging describes the scenario at which skin is first pushed above and beyond the guard tooth, such that the skin may then undesirably bulge downwards and establish a contact with the reciprocally moving cutter blade and/or the cutting blade running surface of the guard blade when the guard blade is pushed against and along the skin during haircutting operation. This may accordingly lead to injuries and irritations of the skin.
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The inventors now surprisingly found that if the first angle between a first tangent line of a cutter blade top surface opposite to the cutter blade contact surface, representing the slope of the cutter blade top surface, and a second tangent line between an elevated portion top surface and the cutter blade top surface is smaller than 5°, the skin is advantageously deflected away from the cutter tooth such downward bulging and establishing of a contact of the skin with the cutter tooth could be prevented or at least minimized. Thus, the skin could be protected during haircutting operation and stress may be reduced to the skin during movement of the guard blade along the skin of a user.
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The first angle may be determined at a point of the cutter blade top surface of the cutter tooth at which the first tangent line and the second tangent line cross.
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Furthermore, the improved deflection of the skin may allow for a smoother movement of guard blade along the skin. That is, the guard blade could be moved faster along the skin without risking skin injuries or irritations. Hence, haircutting efficiency may also be accordingly improved.
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No further elements for protecting the skin may be needed, which may simplify a setup of a respective haircutting device comprising a guard blade having one or more of the guard teeth according to the present invention.
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A haircutting device may be generally understood as any device that is able to cut, groom or trim hair. The haircutting device may comprise a cutter blade that is propellable, e.g. via an electric motor. The cutter blade may perform a reciprocal sawing movement with respect to the guard blade for cutting hair.
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The guard tooth may be manufactured by any suitable mechanically resilient material. The guard tooth may be for instance made of or comprising for instance a metal material, a plastic material and/or a composite material. The guard tooth may be suitably dimensioned and shaped to protect a user from contacting one or more cutter teeth of the cutter blade of the haircutting device. In particular, as will also be described in detail further below, the guard tooth may extend beyond the extension direction of the cutter tooth to contact the skin during use of the haircutting device, thus preventing a contact of the skin with the cutter blade.
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The guard blade may comprise a plurality of guard teeth arranged adjacent to each other in a spaced manner for collecting hair in respective cavities created in between the guard teeth. The respective guard teeth may be equally or non-equally distanced from each other.
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The first guard tooth portion may be arranged to face the oppositely arranged cutter tooth. For instance, the cutter tooth may be arranged above the guard tooth in a height direction. Hence, the cutter tooth may be spaced from the skin to be contacted by the guard tooth in the height direction.
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Generally, it is noted that the terms "top", "above", "bottom" and "below" are merely used herein to explain the relative arrangement of the features with respect to the haircutting device and is not construed to mean absolute arrangements. That is, if the hair cutting device is used in an upside-down manner, e.g. when hair of an underside of the chin is to be cut, a respective bottom surface of the haircutting device may accordingly face upwards to be pressed against the downward facing skin of a user for haircutting operation.
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The second guard tooth portion may also be arranged in the lateral direction beyond the first guard tooth portion. In some configurations, the second guard tooth portion may be distanced from the cutter tooth. The first guard tooth portion may comprise a first guard tooth portion height from a bottom side of the guard tooth in the height direction. This may be the height of a plane at which the cutter blade contact surface may contact the cutter blade running surface.
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A lateral direction may be the direction along which the haircutting device is moved during use. A width direction may be the direction perpendicular to the lateral direction. The lateral direction and the width direction may define a plane in which a bottom side of the guard blade may essentially extend. Perpendicular to the lateral and the width direction, the height direction may be defined. It will be appreciated that the directions defined herein are only exemplarily denoted as "lateral", "width" and "height" directions to explain the relative arrangement and spatial relationships of features and may also be denoted differently, as desired.
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An extension of the guard tooth in the lateral direction is not to be construed to a strict linear extension along a straight axis but may include for instance inclinations of one or more portions of the guard tooth with respect to the lateral direction.
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The elevated portion may be provided at a distal tip of the guard tooth. The elevated portion may extend along the lateral direction. For instance, the elevated portion may extend from a distal end of the guard tooth to the first guard tooth portion. Or the elevated portion may be distanced from the first guard tooth portion. One or more elevated portions comprising different elevations above the height of the first guard tooth portion may be provided along the lateral direction. The elevation or height of the elevated portion may be the same or may vary along the extension along the lateral direction. For instance, the elevation may increase from the distal end of the guard tooth tip toward the first guard tooth portion. Further, the elevated portion may comprise sections being arranged essentially extending in a plane spanned by the lateral direction and the width direction and/or may comprise sections being arranged inclined to said plane.
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The cutter blade running surface may be the surface adapted to face and contact at least partially the cutter blade contact surface of the cutter tooth. That is, the cutter blade, and in particular one or more cutter teeth thereof, may run in an at least partially contacting manner along the cutter blade running surface of the guard tooth. The cutter blade running surface may be provided oppositely to the surface of the guard blade adapted to contact the skin. The cutter blade running surface may comprise a smooth surface which may be accordingly surface treated, e.g. ground, to enable a frictionless movement of the cutter blade.
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The relative movement may be a reciprocal or sawing movement of the cutter blade with respect to the guard blade. Hair may be accordingly cut due to the relative reciprocal movement of the cutter teeth with respect to the guard teeth. Suitable sharp edges may be accordingly provided at the cutter blade contact surface and/or the cutter blade running surface for enhancing the haircutting operation. Hair captured between the cutter tooth and the guard tooth may be accordingly easily sheared off.
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In a preferred embodiment, the first angle is in a range of 0° to 5°, more preferably in a range of 0° to 3° and more preferably, the first angle is about 0°.
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Thus, a particular well deflection of the skin could be achieved, while an unnecessary bulky guard blade could be avoided. The inventors surprisingly found that an angle approaching a tangent condition, which is the case when the angle approaches 0°, leads to an improved guidance of the skin that prevents contact of the skin with the cutter blade and in particular with a tip thereof. Thus, when the cutter blade is moved during haircutting operation in the lateral direction along the skin, a bulging of skin beyond the elevated portion top towards the cutter blade and/or a cutting blade running could be prevented.
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In a preferred embodiment, the elevated portion top surface comprises an elevated portion height above the cutter blade running surface of about 0.01 mm to 0.3 mm, preferably of about 0.1 mm to 0.2 mm, more preferably of about 0.14 mm.
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Thus, a particular well uplift of the skin by the elevated portion could be achieved during haircutting operation. That is, the particular elevated portion height may be sufficient to properly deflect the skin upwards and away from the cutter blade. At the same time, the elevated portion top surface may not be bulky, which may accordingly improve a movement of the guard blade along the skin and may accordingly increase the efficiency of the haircutting operation. Furthermore, skin irritation may be reduced due to only minor friction applied to the skin.
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The elevation may be in the height direction, i.e. perpendicular to the movement direction of the guard blade along the skin, for instance the lateral direction. In some configurations, the second guard tooth portion may comprise a height or thickness of 0.8 mm.
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The invention further relates to a guard blade of a hair cutting device, wherein the guard blade comprises a guard blade base portion and at least one guard tooth extending in a lateral direction therefrom, wherein the guard tooth is a guard tooth according to the present invention.
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The above explanations regarding any features and advantages concerning the guard tooth likewise apply to respective features of the guard blade. Thus, an improved guard blade may be provided which may exhibit an increased skin protection while allowing for an efficient haircutting operation.
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The guard blade may be fixedly arranged in a housing of a haircutting device, such that a relative reciprocal movement of the cutter blade movably arranged in the housing of the haircutting device may accordingly allow for cutting or shearing off hair. However, in other configurations, the guard blade may also be movably arranged in the housing of the cutting device.
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The guard blade may be a plate-shaped element extending essentially in the width direction perpendicular to the lateral direction and having a certain length in the lateral direction while having only a minor extension in the height direction perpendicular to both, the lateral direction and the width direction.
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The guard blade may comprise a base portion, from which the respective guard tooth extends in the lateral direction. The guard blade may be integrally formed, such that the guard tooth is integrally connected with the base portion of the guard blade. However, the base portion and the guard tooth may also be separate parts connected to each other.
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The guard blade may be manufactured by any suitable mechanically resilient material. The guard blade may be for instance made of or comprising for instance a metal material, a plastic material and/or a composite material. The guard blade may be suitably dimensioned and shaped to protect a user from contacting one or more cutter teeth of the cutter blade of the haircutting device. In particular, the guard tooth may extend beyond the extension direction of a cutter tooth in the lateral direction to contact the skin during use of the haircutting device and prevent a contact of the skin with the cutter blade.
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The guard blade may comprise an outer surface being in contact with the skin during the haircutting operation. For instance, the guard blade may be provided at the bottom side of a haircutting device, wherein the bottom side may be pressed against a user's skin during the haircutting operation.
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The guard blade may comprise one or more outer guard teeth or edge guard teeth at one or more outer edges of the guard blade in the width direction and may comprise inner guard teeth arranged between the respective outer guard teeth along the width direction. The guard tooth according to the present invention described herein may be preferably an inner guard tooth of the guard blade.
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In a preferred embodiment, at least one guard tooth of the guard blade protrudes, in the lateral direction, beyond at least one cutter tooth of the cutter blade movably arrangeable with respect to the guard blade.
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Thus, an improved skin protection may be achieved since a contact between the skin and the one or more cutter teeth of the cutter blade may be prevented. The guard blade may be moved in a lateral direction along the skin during a haircutting operation, and the guard blade may accordingly contact the skin first at the distal tips of the guard teeth thus preventing a contact of the skin with the reciprocally moving cutter teeth of the cutter blade. Thus, injuries and irritation of the skin could be efficiently avoided.
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The invention further relates to a cutter tooth for a cutter blade of a hair cutting device, the cutter tooth extending in a lateral direction from the cutter blade, wherein the cutter tooth comprises a cutter blade contact surface adapted to face a guard blade arrangeable below the cutter blade for at least partially contacting a cutter blade running surface of a guard tooth of the guard blade with the cutter blade contact surface, wherein the cutter blade comprises a cutter blade top surface opposite to the cutter blade contact surface, and wherein a first angle between a first tangent line of the cutter blade top surface representing the slope of the cutter blade top surface and a second tangent line between an elevated portion top surface of the guard tooth extending in the lateral direction from the cutter blade running surface and in a height direction perpendicular to the lateral direction and the cutter blade top surface is smaller than 5°.
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Thus, improved protection from skin damages and reduced skin irritation may be achieved, while hair cutting efficiency may be enhanced.
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The cutter tooth according to the present invention in particular overcomes the problem of disadvantageous skin harm and irritation in particular due to skin bulging.
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The inventors surprisingly found that if the first angle between a first tangent line of a cutter blade top surface opposite to the cutter blade contact surface, representing the slope of the cutter blade top surface, and a second tangent line between an elevated portion top surface and the cutter blade top surface is smaller than 5°, the skin is advantageously deflected away from the cutter tooth such that a downward bulging contact of the skin with the cutter tooth and in particular the tip portion thereof could be prevented or at least minimized. Thus, the skin could be protected during haircutting operation and stress may be reduced to the skin during movement of the guard blade along the skin of a user.
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Thus, the provision of the cutter blade according to the present invention may allow the provision of a guard blade that is less bulky and could be moved faster along the skin without risking skin injuries or irritations. Hence, haircutting efficiency may be accordingly improved.
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Furthermore, no further elements for protecting the skin may be needed, which may simplify a setup of a respective haircutting device comprising a cutter blade having one or more cutter teeth according to the present invention.
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As described above, the cutter blade may be propellable, e.g. via an electric motor and may perform a reciprocal sawing movement with respect to the guard blade for cutting hair.
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The cutter tooth may be manufactured by any suitable mechanically resilient material. The cutter tooth may be for instance made of or comprising for instance a metal material, a plastic material and/or a composite material. The cutter tooth may be suitably dimensioned and shaped to achieve a protection of a user via a correspondingly formed guard blade such that one or more cutter teeth of the cutter blade of the haircutting device are prevented from contacting the skin. In particular, as will also be described in detail further below, the cutter tooth may be suitably retracted beyond the guard blade against the lateral direction such that a contact of the skin with the cutter blade in particular due to downward bulging of the skin during use of the haircutting device could be prevented.
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The cutter blade may comprise a plurality of cutter teeth arranged adjacent to each other in a spaced manner for collecting hair in respective cavities created in between the cutter teeth. The respective cutter teeth may be equally or non-equally distanced from each other.
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The cutter tooth may be arranged to face an oppositely arranged guard tooth and in particular a first guard tooth portion thereof. For instance, the cutter tooth may be arranged above the guard tooth in a height direction. Hence, the cutter tooth may be spaced from the skin to be contacted by the guard tooth in the height direction. A second guard tooth portion may be arranged in the lateral direction beyond a first guard tooth portion and the second guard tooth portion may be distanced from the cutter tooth. The first guard tooth portion may comprise a first guard tooth portion height from a bottom side of the guard tooth in the height direction. This may be the height of a plane at which the cutter blade contact surface may contact the cutter blade running surface.
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The lateral direction and the width direction may define a plane in which a bottom side of the cutter blade may essentially extend.
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An extension of the cutter tooth in the lateral direction is not to be construed to a strict linear extension along a straight axis but may include for instance inclinations of one or more portions of the cutter tooth with respect to the lateral direction.
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The cutter blade contact surface may be the surface adapted to face and contact at least partially the cutter blade running surface of the guard tooth. That is, the cutter blade, and in particular one or more cutter teeth thereof, may run in an at least partially contacting manner along the cutter blade running surface of the guard tooth. The cutter blade running surface may be provided oppositely to the surface of the guard blade adapted to contact the skin. The cutter blade contact surface may comprise a smooth surface which may be accordingly surface treated, e.g. ground, to enable a frictionless movement of the cutter blade.
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The relative movement may be a reciprocal or sawing movement of the cutter blade with respect to the guard blade. Hair may be accordingly cut due to the relative reciprocal movement of the cutter teeth with respect to the guard teeth. Suitable sharp edges may be accordingly provided at the cutter blade contact surface and/or the cutter blade running surface for enhancing the haircutting operation. Hair captured between the cutter tooth and the guard tooth may be accordingly easily sheared off.
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In a preferred embodiment, the first angle is in a range of 0° to 5°, more preferably in a range of 0° to 3°, and more preferably the first angle is about 0°.
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Thus, a particular well deflection of the skin could be achieved while an unnecessary bulky guard blade could be avoided. The inventors surprisingly found that an angle approaching a tangent condition, which is the case when the angle approaches 0°, leads to an improved guidance of the skin that prevents contact of the skin with the cutter blade. Thus, when the cutter blade is moved during haircutting operation in the lateral direction along the skin, a bulging of skin beyond the elevated portion top towards the cutter blade and/or a cutting blade running surface could be prevented.
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In a preferred embodiment, the cutter tooth comprises a cutter tooth base portion having a first slope, wherein the first slope is represented by a third tangent line of a cutter tooth base portion top surface of the cutter tooth at the cutter tooth base portion, wherein a second angle between the third tangent line and the cutter blade contact surface is 0° to 35°, preferably of about 5° to 20°, more preferably of about 10°.
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Thus, a particular well shaped cutter tooth may be provided that may prevent contact with skin and accordingly skin harm and irritation during haircutting operation. A first slope may represent the inclination of an upper cutter tooth base portion top surface of the cutter tooth at the cutter tooth base portion. The cutter tooth base portion top surface may be formed in a curved and/or in a linear manner. The cutter tooth base portion may be a portion of the cutter tooth proximal to the cutter blade base portion of the cutter blade. For instance, the cutter tooth base portion may be connected to the cutter blade base portion. Hence, the cutter tooth base portion may extend from the cutter blade base portion in the lateral direction L.
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In a preferred embodiment, the cutter tooth comprises a cutter tooth tip portion extending from the cutter tooth base portion in the lateral direction, wherein the cutter tooth tip portion comprises a second slope different than the first slope, wherein the second slope is represented by a fourth tangent line of a cutter tooth tip portion top surface of the cutter tooth at the cutter tooth tip portion, wherein a third angle between the fourth tangent line and the cutter blade contact surface is 15° to 90°, preferably of about 30° to 60°, more preferably of about 45°.
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Thus, a particular well shaped cutter tooth may be provided that may prevent contact with skin and accordingly skin harm and irritation during haircutting operation. A second slope may represent the inclination of an upper cutter tooth tip portion top surface of the cutter tooth at the cutter tooth tip portion. The cutter tooth tip portion top surface may be formed in a curved and/or in a linear manner. The cutter tooth tip portion may be a portion of the cutter tooth spaced apart from the cutter blade base portion of the cutter blade, e.g. via the cutter tooth base portion. For instance, the cutter tooth tip portion may be connected to the cutter tooth base portion. In other words, the cutter tooth tip portion may extend from the cutter tooth base portion in the lateral direction.
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In some configurations, the cutter tooth tip portion may comprise a steeper slope compared to the cutter tooth base portion. Accordingly, a third angle may be larger than the second angle. However, the present invention is not delimited thereto, and in different configurations the second angle and the third angle may be the same, or the second angle may be larger than the third angle.
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In a preferred embodiment, the cutter tooth tip portion comprises a rounding with a cutter edge rounding curvature radius in a range of 0.05 mm to 0.4 mm, preferably in a range of 0.1 mm to 0.3 mm, more preferably about 0.2 mm.
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Thus, skin that may unintentionally contact the cutter edge may be suitably protected from harm and irritation. The rounding may be provided at the interface between the top surface of the cutter tooth base portion and the top surface of the cutter tooth tip portion. Accordingly, the cutter tooth base portion may comprise a slope that is different to a slope of the cutter tooth tip portion. In particular, the slope of the cutter tooth tip portion may be steeper compared to the slope of the cutter tooth base portion. Accordingly, a cutter tooth that may be particularly well defined with respect to the guard blade as described herein to prevent a contact of skin with the cutter blade during haircutting operation. The respective slopes of the cutter tooth tip portion surface and the cutter tooth base portion surface may be suitably adapted based on the rounded cutter edge provided.
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In a preferred embodiment, the cutter tooth tip portion comprises a cutter tooth tip height of about 0.1 to 0.4 mm, preferably of about 0.15 to 0.3 mm, more preferably of about 0.18 mm.
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Thus, an undesired contact of skin with the cutter tooth tip could be suitably prevented. In particular, the tip height may be adapted, such that skin guided above and beyond the elevated portion of the guard tooth may not come into contact with the cutter tooth, and in particular the cutter to tip portion. Hence, skin may be advantageously prevented from touching the reciprocally moving cutter tooth during haircutting operation.
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In some embodiments, the cutter tooth may comprise a height that is below the height of the elevated portion of the guard tooth. However, the present invention is not limited thereto, and the height of the cutter tooth may also be larger than the height of the elevated portion of the guard tooth. Due to the specific form and alignment of the cutter tooth and the guard tooth as described herein, the skin could be properly deflected such that it may not come into contact with the cutter blade. Thus, flexibility in the arrangement and design of both, the guard tooth and the cutter tooth, could be enhanced.
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The present invention further relates to a cutter blade of a hair cutting device, wherein the cutter blade comprises a cutter blade base portion and at least one cutter tooth extending in a lateral direction therefrom, wherein the cutter tooth is a cutter tooth according to the present invention.
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The above explanations regarding any features and advantages concerning the guard tooth, the guard blade and the cutter tooth likewise apply to respective features of the cutter blade. Thus, an improved cutter blade may be provided which may exhibit an increased skin protection while allowing for an efficient haircutting operation.
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The cutter blade may be movably arranged in a housing of a haircutting device, such that a relative reciprocal movement of the cutter blade movably arranged in the housing with respect to the guard blade of the haircutting device may accordingly allow for cutting or shearing off hair.
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The cutter blade may be a plate-shaped element extending essentially in the width direction perpendicular to the lateral direction and having a certain length in the lateral direction while having only a minor extension in the height direction perpendicular to both, the lateral direction and the width direction.
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The cutter blade may comprise a base portion, from which the respective cutter tooth extends in the lateral direction. The cutter blade may be integrally formed, such that the cutter tooth is integrally connected with the base portion of the cutter blade. However, the base portion and the cutter tooth may also be separate parts connected to each other.
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The cutter blade may be manufactured by any suitable mechanically resilient material. The cutter blade may be for instance made of or comprising for instance a metal material, a plastic material and/or a composite material. The cutter blade may be suitably dimensioned and shaped to protect a user from contacting one or more cutter teeth of the cutter blade of the haircutting device. In particular, the guard tooth may extend beyond the extension direction of the cutter tooth in the lateral direction to contact the skin during use of the haircutting device and thus may prevent a contact of the skin with the cutter blade.
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The present invention further relates to a hair cutting device comprising: a guard blade connected to the hair cutting device, wherein the guard blade is a guard blade according to the present invention, or wherein the guard blade comprises at least one guard tooth according to the present invention. The haircutting device further comprises a cutter blade movably connected to the hair cutting device, wherein the cutter blade is a cutter blade according to the present invention, or wherein the cutter blade comprises at least one cutter tooth according to the present invention.
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The above explanations regarding any features and advantages concerning the guard tooth, the guard blade, the cutter tooth and the cutter blade likewise apply to respective features of the hair cutting device. Accordingly, a haircutting device may be provided, which may allow for an improved skin protection while achieving an enhanced haircutting functionality.
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An improved protection from skin damages and reduced skin irritation may be achieved, while hair cutting efficiency may be enhanced.
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The hair cutting device according to the present invention may in particular overcome the problem of disadvantageous skin bulging, as described above.
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A hair cutting device according to the present invention comprising the guard tooth or the guard blade according to the present invention and the cutter tooth or the cutter blade according to the present invention may accordingly enable that the skin is advantageously deflected away from the cutter tooth such that a contact of the skin with the cutter tooth could be prevented or at least minimized. Thus, the skin is protected during haircutting operation and stress may be reduced to the skin during movement of the guard blade along the skin of a user.
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Furthermore, the improved deflection of the skin leading to less unfavorable skin deformation and bulging may allow for a smoother movement of guard blade along the skin. That is, the guard blade could be moved faster along the skin without risking skin injuries or irritations. Hence, haircutting efficiency may also be accordingly improved.
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Further, no further elements except the guard blade for protecting the skin may be needed, which may simplify a manufacturing and setup of the haircutting device.
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The haircutting device may be an electrically driven handheld haircutting device. The haircutting device may comprise a cutter blade that is propellable, e.g. via an electric motor. The cutter blade may perform a reciprocal movement with respect to the guard blade for cutting hair. However, the present invention is not delimited thereto. Thus, a haircutting device may be generally understood as any device that is able to cut, groom or trim hair.
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The haircutting device may comprise a spring assembly that is fixedly mounted on one side in a housing of the haircutting device. The other side of the spring assembly may be mounted to a driving bridge of the haircutting device, which in turn may be adapted to hold the cutter blade. Thus, a reciprocal movement of the cutter blade may be provided by the restoring forces of the spring assembly and a respective movement provided by an electric motor operatively coupled to the driving bridge.
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The spring assembly may comprise an elastic element made of or comprising for instance an elastic material, such as for instance spring steel, which may enable to hold or press the cutter blade upon the guard blade. The driving bridge may mechanically connect the spring assembly with the cutter blade and may be made of or comprise for instance a plastic material.
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The haircutting device may be moved along the skin e.g. in the lateral direction, and the reciprocal movement may occur perpendicular thereto in a width direction of the haircutting device. The haircutting device may be adapted to contact a skin of a user via a bottom side, which may be formed by an outer surface of the guard blade. The cutter blade may be arranged directly above the guard blade. In another configuration the cutter blade may be arranged at least partially directly below the guard blade. In another configuration, the cutter blade may be arranged at least partially distanced from the guard blade.
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The guard blade may be fixedly arranged in the housing, such that the reciprocal movement may move the cutter teeth relatively to the guard teeth. In other configurations, the guard blade may be arranged in a non-fixedly manner in the housing. When the haircutting device is moved in the lateral direction along the skin, hair to be cut may be captured between the cutter teeth and guard teeth. When the hair arrives at the first guard tooth portion, it may be sheared off or cut by the reciprocal or sawing movement of the cutter teeth relative to the guard teeth.
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During use, the haircutting device may be pushed against the skin of a user and may accordingly contact the skin with an outer contact surface arranged e.g. at a bottom side of the hair cutting device. For performing hair cutting operation, the haircutting device may be moved in the pushed condition along the skin, which may be in the lateral direction. Consequently, during movement of the hair cutting device, the skin may be initially contacted by the distal front surface of the guard teeth.
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The hair cutting device may allow to achieve a proper alignment of the shape and distance of the cutter tooth with respect to the guard tooth, and the skin could still be properly deflected such that it may not come into contact with the cutter blade in particular not due to bulging. Thus, flexibility in the arrangement and design of both, the guard tooth and the cutter tooth could be enhanced.
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In a preferred embodiment, the second guard tooth portion comprises a contact surface for contacting skin and hair, and the cutter blade is arranged with respect to the guard blade such that a distance in the lateral direction between the contact surface of the second guard tooth portion at a distal tip and the cutter blade is about 0.4 mm to 1.0 mm, preferably of about 0.55 mm to 0.85 mm, more preferably of about 0.7 mm.
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Thus, by providing the proper distancing between the contact surface and the cutter blade, an unintended contact of the cutter blade with the skin could be suitably prevented, which may provide an enhanced safety of use of the hair cutting device. In particular, an undesired bulging of the skin towards the cutter blade or the cutter blade running surface could be advantageously prevented.
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The contact surface may include the outermost extension of the guard tooth and may comprise for instance in the lateral direction a distal tip for contacting the skin first during a lateral movement of the guard blade along the skin. A respective front contact surface provided at the distal tip may accordingly extend essentially perpendicular to the lateral direction. The front contact surface may mainly extend in a plane spanned by axes of the width direction and the height direction. However, the front contact surface may also comprise one or more portions or areas that are inclined with respect to this plane.
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The contact surface may comprise rounded areas or roundings, such as rounded edges and/or corners. Rounded edges may extend in any desired direction, e.g. the lateral direction, the width direction and/or the height direction. Thus, the skin may be easily guided with a low friction along a distal tip front surface. The rounded edges and/or corners may also comprise a same or similar curvature radius. Or the curvature radius may be at least partially different.
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In a preferred embodiment, the guard blade comprises a plurality of adjacent guard teeth, wherein an intermediate reception cavity for receiving hair is defined between one or more of the plurality of adjacent guard teeth, and/or wherein the cutter blade comprises a plurality of adjacent cutter teeth, wherein an intermediate reception cavity for receiving hair is defined between one or more of the plurality of adjacent cutter teeth.
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Hence, hair could be advantageously captured in the reception cavity when the guard blade is moved in the lateral direction along the skin. The respective guard teeth may be equally or non-equally distanced from each other.
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One or more reception cavities may be provided between two or more adjacent guard teeth of the guard blade. The reception cavities may be similarly or differently shaped.
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For instance, adjacent guard teeth may form a U-shaped reception cavity or a V-shaped reception cavity. Thus, hair may be suitably guided during the movement of the haircutting device to target portions of the guard teeth and/or cutter teeth, where the cutting should occur.
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Other arbitrary forms are of course also conceivable dependent on the shape and arrangement of the adjacent guard teeth and/or cutter teeth. The reception cavities should be generally large enough to receive one or more hairs.
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Corresponding reception cavities also be provided between adjacent cutter teeth.
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The shapes of the guard teeth and the cutter teeth may also be aligned to each other such that they may form together one or more combined reception cavities. Thus, when the guard plate is moved along the skin in the lateral direction, hair to be cut may be captured by the combined cavities formed by the cutter teeth and the guard teeth and may be collected and guided from a distal end of the guard tooth to the first guard tooth portion, wherein the haircutting could be performed.
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Further features, examples, and advantages will become apparent from the following detailed description of preferred embodiments and the accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
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For a better understanding of the present invention, and to illustrate its practicality, figures are provided in the following and reference is made thereto. It should be understood that the figures represent only exemplary embodiments and thus in no way limit the scope of the claimed invention. Identical or like-acting elements are indicated throughout by the same reference signs. Any reference signs in the claims should not be construed as limiting the scope of the claims. The figures are merely schematic representations and serve only to illustrate examples of the disclosure. Further, as used herein, a hyphenated form of a reference sign refers to a specific embodiment of an element and the unhyphenated form of the reference numeral refers to the collective element. For example, a device "44-2" or "44-3" refers to an instance of a device class that can be collectively referred to as device "44" and each of which can be generically referred to as device "44".
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In the accompanying drawings:
- Fig. 1 schematically illustrates a haircutting device according to an embodiment of the present invention;
- Fig. 2 schematically illustrates a side view of a guard tooth and a cutter tooth according to an embodiment of the present invention;
- Fig. 3 schematically illustrates a side view of a guard tooth and a cutter tooth according to an embodiment of the present invention; and
- Fig. 4 schematically illustrates a side view of a guard tooth and a cutter tooth according to an embodiment of the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
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Fig. 1 illustrates a haircutting device 100 according to an embodiment of the present invention. The figure only shows the relevant parts of a haircutting device 100 for performing hair cutting operation. Further common parts, such as an electric motor to drive the parts, a handle to hold the haircutting device 100 etc. that may be additionally provided with the haircutting device 100 have been omitted from the figures but may of course be readily provided by the skilled person with the haircutting device 100 described herein.
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In the depicted embodiment, the hair cutting device 100 comprises a guard blade 20 connected to the hair cutting device 100, wherein the guard blade 20 is a guard blade 20 according to the present invention, or wherein the guard blade 20 comprises at least one guard tooth 21 according to the present invention. The haircutting device 100 further comprises a cutter blade 10 movably connected to the hair cutting device 100, wherein the cutter blade 10 is a cutter blade 10 according to the present invention, or wherein the cutter blade 10 comprises at least one cutter tooth 11 according to the present invention.
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The haircutting device 100 further comprises a spring assembly 1 that is fixedly mounted on one side in a housing 5 of the haircutting device 100. The other side of the spring assembly 1 is mounted to a driving bridge 3 of the haircutting device 100, which in turn is adapted to hold the cutter blade 10. Thus, a reciprocal movement 70 of the cutter blade 10 could be provided by the restoring forces of the spring assembly 1 and a respective movement provided by an electric motor (not depicted) operatively coupled to the driving bridge 3.
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The spring assembly 1 comprises an elastic element made of spring steel, which holds and presses the cutter blade 10 upon the guard blade 20. The driving bridge 3 mechanically connects the spring assembly 1 with the cutter blade 10 and is made of a plastic material.
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In the depicted embodiment, the haircutting device 100 is moved along the skin in a lateral direction L, and the reciprocal movement 70 occurs perpendicular thereto in a width direction W of the haircutting device 100. The haircutting device 100 is adapted to contact a skin 79 of a user via the bottom side 7 (cf. also Fig. 2).
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In the depicted embodiment, the guard blade 20 is fixedly arranged in the housing 5, such that the reciprocal movement 70 of the cutter teeth 11 relatively to the guard teeth 21 is enabled. When the haircutting device 100 is moved in the lateral direction L along the skin 79, hair to be cut could be captured between the cutter teeth 11 and guard teeth 21 and could be sheared off or cut by the reciprocal movement 70 of the cutter teeth 11 relative to the guard teeth 21.
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On the top surface of the guard blade 20, a cutter blade running surface 23 is provided, at which a bottom side of the cutter blade 10 contacts the guard blade 20 (cf. in detail Figs. 2-4). As depicted, the guard blade 20 comprises a guard blade base portion 27 and at least one guard tooth 21 extending in the lateral direction L therefrom, wherein the guard tooth 21 is a guard tooth 21 according to the present invention.
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As shown in Fig. 1, the guard blade 20 may comprise one or more guard teeth 21 including edge guard teeth 21-2 at one or more outer edges of the guard blade 20 in the width direction W and may comprise inner guard teeth 21-1 arranged between the respective outer or edge guard teeth 21-2 along the width direction W. The guard tooth 21 is an inner guard tooth 21-1 of the guard blade 20.
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The guard blade base portion 27 is a plate-shaped element extending essentially in the width direction W perpendicular to the lateral direction L and having a certain length in the lateral direction L while having only a minor extension in the height direction H perpendicular to both, the lateral direction L and the width direction W. In the depicted embodiment, the guard teeth 21 are integrally connected to the guard blade base portion 27, i.e. they are made of one piece.
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Likewise, the cutter blade 10 comprises a cutter blade base portion 73 and at least one cutter tooth 11 extending in a lateral direction L therefrom, wherein the cutter tooth 11 is a cutter tooth 11 according to the present invention.
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In the embodiment depicted in Fig. 1, the cutter blade base portion 73 is a plate-shaped element extending essentially in the width direction W perpendicular to the lateral direction L and having only a certain length in the lateral direction L while having a minor extension in the height direction H perpendicular to both, the lateral direction L and the width direction W. In the depicted embodiment, the cutter teeth 11 are integrally connected to the cutter blade base portion 73, i.e. they are made of one piece.
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During haircutting operation, the haircutting device 100 is pushed against the skin of a user with the bottom side 7. Then, the haircutting device 100 is moved in a pushed condition along the skin 79, e.g. here in the lateral direction L. Accordingly, the skin 79 contacts first a distal tip front surface 47 (cf. Fig. 2) of the guard teeth 21.
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At least one guard tooth 21 of the guard blade 20 protrudes, in the lateral direction L, beyond at least one cutter tooth 11 of the cutter blade 10 movably arrangeable with respect to the guard blade 20. Thus, an improved skin protection is achieved since a contact between the skin 79 and the one or more cutter teeth 11 of the cutter blade 10 is prevented. Hence, when the guard blade 20 is moved in a lateral direction L along the skin 79 during a haircutting operation, the guard blade 20 accordingly contacts the skin 79 at the distal tips 45 of the guard teeth 23 instead of contacting the reciprocally moving cutter teeth 11 of the cutter blade 10. It is noted that not every single cutter tooth 11 and guard tooth 21 is labeled in Fig. 1 for representability reasons.
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In the depicted embodiment, the guard blade 20 comprises a plurality of adjacent guard teeth 21, wherein an intermediate reception cavity 69 for receiving hair is defined between one or more of the plurality of adjacent guard teeth 21, and the cutter blade 10 comprises a plurality of adjacent cutter teeth 11, wherein an intermediate reception cavity 69 for receiving hair is defined between one or more of the plurality of adjacent cutter teeth 11. It is noted that not every single cavity 69 is labeled in Fig. 1 for representability reasons. Hence, hair to be cut could be captured in the one or more cavities 69 when the guard blade 20 is moved along the lateral direction L along the skin 79. With reference to Fig. 1, it is noted that in case corresponding cavities 69 are formed by adjacent cutter teeth 11, and the cavities of the guard teeth 21 and cutter teeth 11 are aligned to form combined cavities 69 for capturing hair. The guard teeth 21 are further equally distanced, as depicted in Fig. 1. However, in different configurations, they could also be non-equally distanced.
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Detailed aspects of guard blade 20 and the cutter blade10 are described hereinafter the with respect to Figs. 2 to 4. Figs. 2 to 4 schematically illustrate each a side view of a guard tooth 20 and a cutter tooth 10 according to respective embodiments of the present invention. With particular reference to Figs. 3 and 4, it is depicted the guard tooth 21 for the guard blade 20 of the hair cutting device 100, the guard tooth 21 extending in the lateral direction L from the guard blade 20. The guard tooth comprises a first guard tooth portion 25 connectable to the guard blade base portion 27, and a second guard tooth portion 29 extending from the first guard tooth portion 25 in the lateral direction L, wherein the first guard tooth portion 25 comprises a cutter blade running surface 23 adapted to face a cutter blade 10 arrangeable above the guard blade 20 for at least partially contacting the cutter blade running surface 23 with a cutter blade contact surface 13. Further, the second guard tooth portion 29 comprises an elevated portion 63 extending in the lateral direction L from the cutter blade running surface 23 and in a height direction H perpendicular to the lateral direction L. As is particularly visible from Fig. 3, a first angle 37 between a first tangent line 31 of a cutter blade top surface 33 opposite to the cutter blade contact surface 13, representing the slope of the cutter blade top surface 33, and a second tangent line 35 between an elevated portion top surface 39 and the cutter blade top surface 33 is smaller than 5°.
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Hence, the skin 79 is advantageously deflected away from the cutter tooth 11 such that a contact of the skin 79 with the cutter tooth 11 could be prevented or at least minimized. In particular, a disadvantageous skin bulging could be prevented.
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In the depicted embodiment of Fig. 2, the deflection of skin 79 is shown, when the guard tooth 20 is moved in the lateral direction L. It is noted that the skin 79 is not explicitly depicted in Figs. 3 and 4 for representability reasons. However, since the elements shown in Figs. 3 and 4 correspondingly operate, a similar skin deflection as shown in Fig. 2 could be assumed.
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The guard tooth 20 contacts the skin 79 with the contact surface 44 during haircutting operation. To perform haircutting, in the configurations shown in the figures, the guard blade 20 is moved against the height direction H towards skin 79. The skin 79 accordingly contacts the base contact surface 44-4 arranged at the bottom side 7 of the guard blade 20. Due to the pressure applied, the skin 79 forms a compressed flat skin portion 79-1. Now, when the guard blade 20 is moved along the skin 79 in the lateral direction L, the skin is pushed upwards or heaped due to the friction of the skin 79 with a front contact surface 44-2 of the guard blade 20. The respective heaped skin portion 79-2 is deflected essentially upwards in the height direction H and guided along the front contact surface 44-2 and an elevated portion top surface 39 of the elevated portion 63. Since the first angle 37 between the first tangent line 31 of the cutter blade top surface 33 and the second tangent line 35 between the elevated portion top surface 39 and the cutter blade top surface 33 is smaller than 5° (cf. Fig. 3), the heaped skin portion 79-2 is advantageously deflected away from the cutter tooth 11 such that no or only a reduced bulging, as indicated by the downward pointing arrow 81 could occur and thus contact of the skin 79 with the cutter tooth 11 and in particular with the cutter tooth tip portion 55 could be prevented. As depicted, the first angle 37 is determined at a point of the cutter blade top surface 33 of the cutter tooth 11 at which the first tangent line 31 and the second tangent line 35 cross.
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The contact surface 44 of the guard tooth 21 also includes an inner contact surface 44-3 and an outer contact surface (not depicted) oppositely arranged in the width direction W. These contact surfaces 44 may be suitably shaped such that hair to be cut could be guided along said contact surfaces 44.
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The first guard tooth portion 25 extends from the second guard tooth portion 29 with a first tooth portion length 56 against the lateral direction L toward the guard blade base portion 27 (not depicted, cf. Fig. 1) of the guard blade 20. The cutter tooth 11 is arranged essentially above the first guard tooth portion 25 where the cutting of the hair occurs. The first guard tooth portion 25 comprises a first guard tooth portion height 67 from the bottom side 7 of the guard tooth 21, and in particular from the base contact surface 44-4, in the height direction H. As depicted, this may be the height of a plane at which the contact blade contact surface 13 contacts the cutter blade running surface 23.
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The guard tooth 21 is suitable to generally prevent a contact of skin with the cutter tooth 11 arranged in the depicted embodiment above and laterally retracted from the distal tip 45 of the guard tooth 21 (cf. Figs. 2 to 4). In particular, a skin bulging 81 could be prevented.
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The second guard tooth portion 29 has a second tooth portion length 77 along the lateral direction L from a distal tip 45 of the guard tooth 21 to the first guard tooth portion 25 in a range of up to 0.2 mm to 1.2 mm, preferably in a range of up to 0.3 mm to 0.8 mm, more preferably in a range of up to 0.45 mm. In other configurations, the length may however also be larger or smaller, as desired.
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Furthermore, the cutter blade running surface 23 is arranged on a top side of the guard tooth 21. The cutter blade running surface 23 is accordingly formed such that a bottom side of the cutter blade 10 could contact the cutter blade running surface 23 and could be moved in a reciprocal manner parallel to a width direction W. The cutter blade running surface 23 is accordingly surface treated, e.g. ground, to allow a smooth reciprocal movement of the cutter blade 10 thereon. Accordingly, hair captured in the reception cavities 69 could be properly cut or sheared off.
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In particular, the first angle 37 is in a range of 0° to 5°, more preferably in a range of 0° to 3°, and more preferably the first angle 37 is about 0°.
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Thus, a particular well deflection of the skin 79 could be achieved while an unnecessary bulky guard blade 23 could be avoided. The inventors surprisingly found that a first angle 37 approaching a tangent condition, which is the case when the angle approaches 0°, leads to an improved guidance of the skin 79 that prevents contact of the skin 79 with the cutter blade 10. Thus, when the cutter blade 10 is moved during haircutting operation in the lateral direction L along the skin 79, a bulging 81 of skin 79 beyond the elevated portion 63 towards the cutter blade 10 and/or the cutting blade running surface 23 of the guard blade 20 could be prevented.
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As is best visible from Figs. 2 and 4, the elevated portion top surface 39 comprises an elevated portion height 65 above the cutter blade running surface 23 of about 0.01 mm to 0.3 mm, preferably of about 0.1 mm to 0.2 mm, more preferably of about 0.14 mm.
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The elevated portion 63 is provided at a distal tip 45 of the guard tooth 20. The elevated portion 63 extends along the lateral direction L. As depicted, the elevated portion 63 extends from the distal tip 45 of the guard tooth 21 to the first guard tooth portion 25. The elevated portion 63 is distanced from the first guard tooth portion 25. The elevated portion 63 comprises an elevated portion top surface 39 having an extension in the lateral direction L and in the width direction W. However, in different configurations, more than one elevated portion 63 may be provided, which may for instance comprise different elevated portion heights above a height of the first guard tooth portion 25, wherein the height may accordingly vary along the lateral direction L. For instance, the elevated portion height 65 may increase from the distal end of the tip toward the first guard tooth portion 25.
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Furthermore, again with particular reference to Figs. 3 and 4, it is depicted a cutter tooth 11 for a cutter blade 10 of a hair cutting device 100, the cutter tooth 11 extending in a lateral direction L from the cutter blade 10. The cutter tooth 11 comprises a cutter blade contact surface 13 adapted to face a guard blade 20 arrangeable below the cutter blade 10 for at least partially contacting a cutter blade running surface 23 of a guard tooth 21 of the guard blade 20 with the cutter blade contact surface 13. Further, the cutter blade 10 comprises a cutter blade top surface 33 opposite to the cutter blade contact surface 13. As is particularly visible from Fig. 3, a first angle 37 between a first tangent line 31 of the cutter blade top surface 33 representing the slope of the cutter blade top surface 33 and a second tangent line 35 between an elevated portion top surface 39 of the guard tooth 21 extending in the lateral direction L from the cutter blade running surface 23 and in a height direction H perpendicular to the lateral direction L and the cutter blade top surface 33 is smaller than 5°.
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Thus, improved protection from skin damages and reduced skin irritation may be achieved, while hair cutting efficiency may be enhanced. The cutter tooth 11 according to the present invention in particular overcomes the problem of disadvantageous skin harm and irritation due to skin bulging. The inventors surprisingly found that if the first angle 37 between the first tangent line 31 of the cutter blade top surface 33 opposite to the cutter blade contact surface 13, representing the slope of the cutter blade top surface 33, and a second tangent line 35 between an elevated portion top surface 39 and the cutter blade top surface 33 is smaller than 5°, the skin 79 is advantageously deflected away from the cutter tooth 11 such that a contact of the skin 79 with the cutter tooth 11 could be prevented or at least minimized. Thus, the skin 79 is protected during haircutting operation and stress is reduced to the skin 79 during movement of the guard blade 20 along the skin 79 of a user, for instance in the lateral direction L.
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Thus, the provision of the cutter blade 20 according to the present invention may allow the provision of a guard blade 10 that is less bulky and could be moved faster along the skin 79 without risking skin injuries or irritations. Hence, haircutting efficiency may be accordingly improved.
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Furthermore, no further elements for protecting the skin 79 may be needed, which may simplify a setup of a respective haircutting device comprising the cutter blade 10 having one or more of the cutter tooth 11 according to the present invention.
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As described above, the cutter blade 10 that may be propellable, e.g. via an electric motor and may perform a reciprocal sawing movement 70 with respect to the guard blade 20 for cutting hair.
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The cutter tooth 11 may be manufactured by any suitable mechanically resilient material. The cutter tooth 11 may be for instance made of or comprising for instance a metal material, a plastic material and/or a composite material. The cutter tooth 11 may be suitably dimensioned and shaped to achieve a protection of a user via a correspondingly formed guard blade 20 such that one or more cutter teeth 11 of the cutter 10 blade of the haircutting device 100 are prevented from contacting the skin 79. In particular, as depicted in the embodiments of Figs. 2 to 4, the cutter tooth 11 is suitably retracted beyond the guard blade 20 against the lateral direction L, such that a contact of the skin 79 with the cutter blade 11 during use of the haircutting device 100 could be prevented.
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As depicted in Fig. 1, the cutter blade 11 comprises a plurality of cutter teeth 11 arranged adjacent to each other in a spaced manner for collecting hair in respective cavities 69 created in between the cutter teeth 11. The respective cutter teeth 11 may be equally or non-equally distanced from each other.
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The cutter tooth 11 is arranged to face an oppositely arranged guard tooth 21 and in particular a first guard tooth portion 25 thereof. The cutter tooth 11 is arranged above the guard tooth 21 in a height direction H. Hence, the cutter tooth 11 is spaced from the skin 79 to be contacted by the guard tooth 21 in the height direction H. A second guard tooth portion 29 may be arranged in the lateral direction L beyond the first guard tooth portion 25 and the second guard tooth portion 29 may be distanced from the cutter tooth 11.
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The lateral direction L and the width direction W define a plane in which a bottom side of the cutter blade 20 essentially extends.
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The cutter blade contact surface 13 is the surface adapted to face and contact at least partially the cutter blade running surface 23 of the guard tooth 20. That is, the cutter blade 11, and in particular one or more cutter teeth 11 thereof, run in an at least partially contacting manner along the cutter blade running surface 23 of the guard tooth 20. The cutter blade running surface may be provided oppositely to the surface of the guard blade adapted to contact the skin. The cutter blade contact surface 13 comprises a smooth surface to enable a frictionless movement of the cutter blade 10.
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The depicted relative movement 70 is a reciprocal or sawing movement of the cutter blade 10 with respect to the guard blade 21. Hair could be accordingly cut due to the relative reciprocal movement of the cutter teeth 11 with respect to the guard teeth 21. Suitable sharp edges may be accordingly provided at the cutter blade contact surface 13 and/or the cutter blade running surface 23 for enhancing the haircutting operation. Hair captured between the cutter tooth 11 and the guard tooth 21 could be accordingly easily sheared off.
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In particular, the first angle 37 is in a range of 0° to 5°, more preferably in a range of 0° to 3°, and more preferably the first angle 37 is about 0°.
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Thus, a particular well deflection of the skin 79 could be achieved while an unnecessary bulky guard blade 20 could be avoided. The inventors surprisingly found that a first angle 37 approaching a tangent condition, which is the case when the angle approaches 0° leads to an improved guidance of the skin 79 that prevents contact of the skin 79 with the cutter blade 10. Thus, when the cutter blade 10 is moved during haircutting operation in the lateral direction L along the skin 79, a bulging of skin 79 beyond the elevated portion 63 towards the cutter blade 10 and/or the cutting blade running surface 23 of the guard blade 20 could be prevented.
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As is best visible from Fig. 4, the cutter tooth 11 comprises a cutter tooth base portion 49 having a first slope, wherein the first slope is represented by a third tangent line 41 of a cutter tooth base portion top surface 51 of the cutter tooth 11 at the cutter tooth base portion 49. Further, a second angle 83 between the third tangent line 41 and the cutter blade contact surface 13 is 0° to 35°, preferably of about 5° to 20°, more preferably of about 10°.
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Thus, a particular well shaped cutter tooth 11 could be provided that prevents contact with skin 79 and accordingly skin harm and irritation during haircutting operation. A first slope may represent the inclination of an upper cutter tooth base portion top surface 51 of the cutter tooth 11 at the cutter tooth base portion 49. In the embodiment depicted in Fig. 4, the cutter tooth base portion top surface 51 is formed in an essentially linear manner. However, the cutter tooth base portion top surface 51 may also be provided in a curved manner, as depicted for instance in the embodiment shown in Fig. 3.
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The cutter tooth base portion 49 is a portion of the cutter tooth 11 proximal to the cutter blade base portion 73 of the cutter blade 10. As depicted, the cutter tooth base portion 49 is connected to the cutter blade base portion 73. Hence, the cutter tooth base portion 49 extends from the cutter blade base portion 73 in the lateral direction L.
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Furthermore, the cutter tooth 11 comprises a cutter tooth tip portion 55 extending from the cutter tooth base portion 49 in the lateral direction L, wherein the cutter tooth tip portion 55 comprises a second slope different than the first slope. The second slope is represented by a fourth tangent line 57 of a cutter tooth tip portion top surface 59 of the cutter tooth 11 at the cutter tooth tip portion 55. A third angle 61 between the fourth tangent line 57 and the cutter blade contact surface 13 is 15° to 90°, preferably of about 30° to 60°, more preferably of about 45°.
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Thus, a particular well shaped cutter tooth 11 could be provided that prevents contact with skin 79 and accordingly skin harm and irritation during haircutting operation. A second slope may represent the inclination of an upper cutter tooth tip portion top surface 59 of the cutter tooth 11 at the cutter tooth tip portion 55. In the embodiment depicted in Fig. 4, the cutter tooth tip portion top surface 59 is formed in an essentially linear manner. However, cutter tooth tip portion top surface 59 may also be provided in a curved manner, as depicted for instance in the embodiment shown in Fig. 3.
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The cutter tooth tip portion 55 is a portion of the cutter tooth 11 spaced apart from the cutter blade base portion 73 of the cutter blade 10, e.g. in the lateral direction L via the cutter tooth base portion 49. Hence, the cutter tooth tip portion 55 is connected to cutter tooth base portion 49. In other words, the cutter tip portion 55 extends from the cutter tooth base portion 73 in the lateral direction L. In the depicted configuration, the cutter tooth tip portion 55 comprises a steeper slope compared to the cutter tooth base portion 49. Accordingly, the third angle 61 is in the depicted embodiment larger than the second angle 83.
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As is indicated in Figs. 2 and 4, the cutter tooth tip portion 55 comprises a rounding with a cutter edge rounding curvature radius R2 in a range of 0.05 mm to 0.4 mm, preferably in a range of 0.1 mm to 0.3 mm, more preferably about 0.2 mm.
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As is particularly visible from Fig. 4, the rounding is provided at the interface between the cutter tooth base portion top surface 51 and the cutter tooth tip portion top surface 59. Accordingly, a transition between the slopes of the upper surfaces of the cutter tooth base portion 49 and the cutter tooth tip portion 55 is achieved. In the depicted embodiment, the slope of the cutter tooth tip portion 55 is steeper compared to the slope of the cutter tooth base portion 49.
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Further, the cutter tooth tip portion 55 comprises a cutter tooth tip height 71 of about 0.1 to 0.4 mm, preferably of about 0.15 to 0.3 mm, more preferably of about 0.18 mm.
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The cutter tooth tip height 71 is adapted, such that skin 79 guided above and beyond the elevated portion 63 of the guard tooth 21 could not come into contact with the cutter tooth 11, and in particular not with the cutter to tip portion 55. As depicted in Figs. 2 and 4, the cutter tooth tip height 71 could be larger than the elevated portion height 65 of the guard tooth 21. However, due to the specific form and alignment of the cutter tooth 11 and the guard tooth 21 described herein, the skin 79 could be properly deflected such that it essentially does not come into contact with the cutter blade 10. In other configurations, the cutter tooth tip height 71 could be smaller than the elevated portion height 65 of the guard tooth 21.
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With particular reference to Fig. 2, it is shown that the second guard tooth portion 29 comprises a contact surface 44 for contacting skin and hair, wherein the cutter blade 10 is arranged with respect to the guard blade 20 such that a distance D in the lateral direction L between the contact surface 44 of the second guard tooth portion 29 at a distal tip 45 and the cutter blade 10 is about 0.4 mm to 1.0 mm, preferably of about 0.55 mm to 0.85 mm, more preferably of about 0.7 mm.
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As is shown in Fig. 2, the guard tooth 21 comprises at its top surface the cutter blade running surface 23 which contacts the cutter blade contact surface 13 arranged at the bottom surface of the cutter tooth 11. The distal tip 45 of the guard tooth 21 comprises, in a view perpendicular to the lateral direction L, an essentially rectangular cross-sectional shaped distal tip front surface 47. The essentially rectangular cross-sectional shape may include any cross-sectional shape that may comprise four sides essentially rectangularly connected to each other. However, the extensions of respective opposite sides may vary, such that the essentially rectangular shape may be formed for instance as a rectangle comprising two opposing longer sides and two opposing shorter sides. Or the four sides may be equal such that the essentially rectangular cross-sectional shape corresponds to a square.
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The distal tip 45 is essentially rectangularly formed also in a front view and has rounded edges 53. This increases the contact surface of the guard tooth 21 and accordingly reduces irritations and discomfort of the skin when the distal tip 45 contacts the skin.
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Thus, an initial contact of skin with the second guard tooth portion 29 may be advantageously established via the cross-sectional shaped distal tip front surface 47. Accordingly, pressure applied to the skin 79 may be advantageously distributed over a larger area and therefore skin harm and irritation may be reduced. Furthermore, the provision of the essentially rectangular cross-sectional shaped distal tip front surface 47 may allow to efficiently guide hair contacting the distal tip front surface 47 along its sides towards the proximal regions of the guard tooth 21, for instance towards the first tooth portion 25, where the cutting may occur.
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The rounded edges 53 have a rounded edge curvature radius R1, which is exemplarily depicted for the bottom rounded edge 53. It is apparent, that also the upper rounded edge 53 may comprise a corresponding curvature radius that may be the same or different to the rounded edge curvature radius R1 depicted for the bottom rounded edge 53. Generally, rounded edges 53 be provided for respective edges extending in any directions, e.g. the lateral direction L, the width direction W and/or the height direction H. Thus, the skin 79 may be easily guided with a decreased friction along the distal tip front surface. However, in different embodiments, also no rounded edges 53 may be provided.
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The second guard tooth portion 29 comprises a second guard tooth portion height 75 perpendicular to the lateral direction L in the height direction H. The second guard tooth portion height 75 may be in a range of 0.3 mm to 1.2 mm, preferably in a range of 0.4 mm to 1 mm and more preferably in a range of 0.7 mm to 0.8 mm.
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Thus, an improved stability of the guard tooth 21 in the height direction H may achieved while an improved skin protection could be obtained. Accordingly, the guard tooth 21 may be sufficiently stable with respect to external forces potentially deflecting the guard tooth 21 essentially in or against the height direction H. The guard tooth 21 may accordingly not undesirably deform during the haircutting operation. At the same time, the guard tooth 21 may be sufficiently small to avoid a bulky shape in the height direction H. Hence, handling during the haircutting operation may be facilitated. The second guard tooth portion height 75 may vary in the above noted ranges or may be the same along the lateral direction L. In other configurations, the height may also be generally larger or smaller, as desired.
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The second guard tooth portion 29 may have a second guard tooth portion length 77 along the lateral direction L from a distal tip 45 of the guard tooth 21 to the first guard tooth portion 25 in a range of up to 0.2 mm to 1.2 mm, preferably in a range of up to 0.3 mm to 0.8 mm, more preferably in a range of up to 0.45 mm.
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Thus, a proper stability of the guard tooth 21 in the length direction L may be achieved while an improved skin protection may be obtained. The guard tooth 21 may accordingly not undesirably deform during the haircutting operation. The second guard tooth portion length 77 of the second guard tooth portion 29 may be suitably selected to enable a proper skin and hair guidance along the lateral direction L. Furthermore, the second guard tooth portion length 77 may be suitably set to achieve a desired distancing of skin 79 approaching the cutter blade 10 at the distal tip 45, e.g. during use of the hair cutting device 100. In other configurations, the second guard tooth portion length 77 may also be generally larger or smaller, as desired.
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Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed disclosure, from the study of the drawings, the disclosure, and the appended claims. In the claims the word "comprising" or "including" does not exclude other elements or steps and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.
LIST OF REFERENCE SIGNS
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- 1
- spring assembly
- 3
- driving bridge
- 5
- housing
- 7
- bottom side
- 10
- cutter blade
- 11
- cutter tooth
- 13
- cutter blade contact surface
- 20
- guard blade
- 21
- guard tooth
- 21-1
- inner guard tooth
- 21-2
- edge guard tooth
- 23
- cutter blade running surface
- 25
- first guard tooth portion
- 27
- guard blade base portion
- 29
- second guard tooth portion
- 31
- first tangent line
- 33
- cutter blade top surface
- 35
- second tangent line
- 37
- first angle
- 39
- elevated portion top surface
- 41
- third tangent line
- 44
- contact surface
- 44-2
- front contact surface
- 44-3
- inner contact surface
- 44-4
- base contact surface
- 45
- distal tip
- 47
- distal tip front surface
- 49
- cutter tooth base portion
- 51
- cutter tooth base portion top surface
- 53
- rounded edge
- 55
- cutter tooth tip portion
- 56
- first tooth portion length
- 57
- fourth tangent line
- 59
- cutter tooth tip portion top surface
- 61
- third angle
- 63
- elevated portion
- 65
- elevated portion height
- 67
- first guard tooth portion height
- 69
- reception cavity
- 70
- cutter blade movement
- 71
- cutter tooth tip height
- 73
- cutter blade base portion
- 75
- second guard tooth portion height
- 77
- second guard tooth portion length
- 79
- skin
- 79-1
- flat skin portion
- 79-2
- heaped skin portion
- 81
- bulging direction
- 83
- second angle
- 100
- hair cutting device
- L
- lateral direction
- H
- height direction
- W
- width direction
- R1
- rounded edge curvature radius
- R2
- cutter edge rounding curvature radius
- D
- distance