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 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 base portion of the guard blade, and a second guard tooth portion extending from the first guard tooth portion in the lateral direction; wherein, in a view perpendicular to the lateral direction, the first guard tooth portion comprises a first guard tooth portion section having an essentially non-rectangular cross-sectional shape; and the second guard tooth portion comprises a second guard tooth portion section having an essentially rectangular cross-sectional shape.
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Thus, improved protection from skin damages and reduced skin irritation may be achieved, while hair cutting efficiency may be enhanced. In particular, the essentially rectangular cross-sectional shape of the second guard tooth portion section may allow for an increased area for contacting the skin during movement of the guard tooth along the skin. Accordingly, the pressure applied to the skin may be distributed over a larger area, which may accordingly reduce stress to the skin during movement of the guard blade along the skin of a user.
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Furthermore, the essentially non-rectangular cross-sectional shape may allow the provision of sharp edges, which do not contact the skin and enable an efficient interaction between the guard tooth and the cutter tooth and thus may allow for an improved haircutting performance. Safety and efficiency of the haircutting device may be accordingly enhanced due to an advantageous transition from the essentially rectangular cross-sectional shape to the essentially non-rectangular cross-sectional shape. 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 tooth according to the present invention. Furthermore, providing an essentially rectangular cross-sectional shape at the second guard tooth portion may facilitate a manufacturing of the guard tooth and may improve a guidance of hair to be cut along the side surfaces of the essentially rectangular cross-sectional shaped guard tooth portion during the hair cutting operation.
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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 a 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 an 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. 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.
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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, a 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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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 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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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 partial inclinations of one or more portions of the guard tooth with respect to the lateral direction.
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Furthermore, the non-rectangular cross-sectional shape may vary along the first tooth portion, such that for instance its cross-sectional area may increase or decrease or such that the shape may slightly vary, even though its non-rectangular cross-sectional shape should be generally maintained. Likewise, the rectangular cross-sectional shape may vary along the second tooth portion, such that its cross-sectional area may increase or decrease or such that the shape may slightly vary, even though its rectangular cross-sectional shape should be generally maintained.
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The first guard tooth portion section and the second guard tooth portion section may be understood as subsections of the respective first guard tooth portion and the second guard tooth portion. That is, the first guard tooth portion may also comprise further sections that are not in an essentially non-rectangular cross-sectional shape and the second guard tooth portion may also comprise further sections that are not in an essentially rectangular cross-sectional shape.
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An 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. Furthermore, the essentially rectangular cross-sectional shape may further comprise roundings at one or more corners leading to round edges of the second guard tooth portion extending along the lateral direction as described in detail herein further below.
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The essentially non-rectangular cross-sectional shape may include shapes that allow the provision of acute angles at the top side of the first tooth portion, such as a trapezoid described further below in greater detail. Thus, suitably low cutting forces may be achieved, and a potential cutter separation may be prevented. Furthermore, also the essentially non-rectangular cross-sectional surface may also comprise respective roundings at one or more corners, if desired.
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In a preferred embodiment, the second guard tooth portion section is formed by a distal tip of the guard tooth for contacting skin or hair, and the distal tip comprises, in a view perpendicular to the lateral direction, an essentially rectangular cross-sectional shaped distal tip front surface.
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Thus, an initial contact of skin with the second guard tooth may be advantageously established via the cross-sectional shaped distal tip front surface that has a larger surface compared to the non-rectangular cross-sectional surface of the first guard tooth portion. Accordingly, pressure applied to the skin 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 may allow to efficiently guide hair contacting the distal tip front surface along its sides towards the proximal regions of the guard tooth, for instance towards the first tooth portion, where the cutting may occur.
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The distal tip may include the outermost extension of the guard tooth in the lateral direction. The distal tip front surface may accordingly extend essentially perpendicular to the lateral direction. In other words, the distal tip front surface may mainly extend in a plane spanned by axes of the width direction and the height direction. However, the distal tip front surface may also comprise one or more portions or areas that are inclined with respect to this plane. For instance, the surface may comprise rounded areas or roundings as described in detail herein further below. The roundings may include roundings of edges extending in any directions, e.g. the lateral direction, the width direction or the height direction. Thus, the skin may be easily guided with a low friction along the essentially rectangular cross-sectional shaped distal tip front surface.
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In a preferred embodiment, the essentially rectangular cross-sectional shape of the second guard tooth portion section comprises a maximum area in a range of 0.2 mm2 to 1 mm2, preferably in a range of 0.3 mm2 to 0.46 mm2 and more preferably of about 0.39 mm2.
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Thus, an improved skin protection may be obtained while maintaining an efficient guidance of hair to the areas of the guard tooth where the cutting should be performed. If the area of the essentially rectangular cross-sectional shape of the second guard tooth portion is chosen too small, the pressure may not be suitably distributed, and harm or damage of the skin may occur. Simultaneously, if the area of the essentially rectangular cross-sectional shape of the second guard tooth portion is chosen too large, no efficient hair guidance may be achieved, which may impair the overall hair cutting performance. Furthermore, a particular smooth transition of hair from the second guard tooth portion to the first guard tooth portion may be advantageously achieved in the above noted ranges. Even though a certain maximum area may be desirable, the second guard tooth portion section may of course also comprise variations in the cross-sectional area along its extension in the lateral direction. In other configurations, the maximum area may also be generally larger or smaller, as desired.
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In a preferred embodiment, the essentially rectangular cross-sectional shaped distal tip front surface comprises round edges with a curvature radius in a range 0.05 mm to 1 mm, preferably in a range of 0.1 mm to 0.4 mm and more preferably of about 0.3 mm.
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Thus, the pressure distribution to the skin may be further enhanced, and skin safety and comfort of use during haircutting operation may be further improved. In particular, guidance of the skin along the curved surfaces and edges may be facilitated when the haircutting device is moved along the skin, e.g. in the lateral direction. In this respect, if the curvature radius is chosen too small, the advantageous effect of additional skin protection may not be sufficiently achieved. Similarly, if the curvature radius is selected too large, the desired guidance of hair may become difficult. Furthermore, the provision of an extensive curvature radius be may also impair the desired essentially rectangular cross-sectional shape. In other words, a ball or sphere-like appearance of the distal tip of the guard tooth should be prevented. Accordingly, the above noted curvature radius ranges may provide an optimum balance between improved skin protection and efficient hair guidance and cutting.
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One or more edges may comprise the same curvature radius. For instance, all edges may comprise the same curvature radius. Or one or more edges may comprise a different curvature radius, such that a first edge may comprise a first curvature radius and a second edge may comprise a second curvature radius different to the first curvature radius. In other configurations, the curvature radius may also be generally larger or smaller, as desired.
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The round edges may include roundings extending in any directions, e.g. the lateral direction, the width direction or the height direction. Thus, the skin may be easily guided with a decreased friction along the essentially rectangular cross-sectional shaped distal tip front surface.
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In a preferred embodiment, the second guard tooth portion section comprises a width perpendicular to the lateral direction in a range of 0.2 mm to 1 mm, preferably in a range of 0.3 mm to 0.8 mm and more preferably in a range of 0.5 mm to 0.6 mm.
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Thus, an improved stability of the guard tooth in the width direction may achieved while an improved skin protection and haircutting properties of the haircutting device are obtained. Accordingly, the guard tooth may be sufficiently stable with respect to external forces potentially deflecting the tooth essentially in or against the width direction. The tooth may accordingly not undesirably deform during the haircutting operation. At the same time, the guard tooth may be sufficiently small in a width direction such that preferably a suitable number of guard teeth may be provided at the guard blade along the width direction to enable an efficient haircutting operation. The second guard tooth portion section width may vary in the above noted ranges or may be the same along the second guard portion. In other configurations, the width may also be generally larger or smaller, as desired.
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In a preferred embodiment, the second guard tooth portion section comprises a height perpendicular to the lateral direction 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 in the height direction may achieved while an improved skin protection and haircutting properties of the haircutting device are obtained. Accordingly, the guard tooth may be sufficiently stable with respect to external forces potentially deflecting the tooth essentially in or against the height direction. The tooth may accordingly not undesirably deform during the haircutting operation. At the same time, the guard tooth may be sufficiently small to avoid a bulky shape in the height direction. Hence, handling during the haircutting operation may be facilitated. The second guard tooth portion section height may vary in the above noted ranges or may be the same along the second guard portion. In other configurations, the height may also be generally larger or smaller, as desired.
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In a preferred embodiment, the second guard tooth portion has a length along the lateral direction from a distal end of the guard tooth to the first guard tooth portion 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. Thus, a proper stability of the guard tooth in the length direction may be achieved while an improved skin protection and improved haircutting properties of the haircutting device are obtained. The tooth may accordingly not undesirably deform during the haircutting operation. The length of the second guard tooth portion may be suitably selected to enable a proper skin and hair guidance along the lateral direction. Furthermore, the length may be suitably set to achieve a desired distancing of skin approaching the cutter blade from a frontal end, e.g. during use of the hair cutter. In other configurations, the length may also be generally larger or smaller, as desired.
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In a preferred embodiment, the essentially non-rectangular cross-sectional shape of the first guard tooth portion section forms a trapezoid comprising two unevenly long parallel legs and two inclined legs connecting the two unevenly long parallel legs, wherein the first guard tooth portion section comprises a cutter blade running surface formed by the longer one of the unevenly long parallel legs, wherein the cutter blade running surface is adapted to face a cutter blade arrangeable above the guard blade for at least partially contacting the cutter blade running surface.
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Thus, particular low cutting forces may be achieved at the cutter blade running surface. The cutter blade running surface may be the surface adapted to face and contact at least partially a cutter tooth contact surface of a cutter tooth. That is, the cutter tooth 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 to enable a frictionless movement of the above cutter blade.
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An acute angle may be accordingly defined at the top surface of the trapezoid and hair may be accordingly cut when the cutter blade reciprocally moves along the cutter blade running surface. During the sawing movement of the cutter blade, hair may be pushed against the acute edge formed at the top side of the trapezoid and may be accordingly separated. The inclined legs may comprise same length such that the acute angles formed at the top side between the longer one of the two unevenly long parallel legs and the inclined legs are the same. Or the inclined legs may comprise different lengths such that the acute angles formed at the top side between the longer one of the two unevenly long parallel legs and the inclined legs may be different.
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In a preferred embodiment, an angle between the longer one of the parallel legs and one or more of the two inclined legs is between 45 and 80 degrees.
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Thus, particular low cutting forces may be achieved accordingly facilitating the haircutting operation. The essentially non-rectangular cross-sectional shape of the first guard tooth portion section may accordingly provide sufficient mechanical stability while at the same time a proper haircutting functionality may be achieved. One or more cutting features comprising one or more sharp edges may be additionally provided at the top side of the trapezoid. Thus, while the stability of the first guard tooth portion section is maintained based on the trapezoidal cross-sectional surface, the haircutting functionality may be further improved.
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In a preferred embodiment, the second guard tooth portion section comprises an elevated portion, wherein the elevated portion comprises a height extending above a height of the first guard tooth portion such that a cross-sectional area of the second guard tooth portion section is larger than a cross-sectional area of the first guard tooth portion section adjacent to the second guard tooth portion section.
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Accordingly, skin protection could be further enhanced since an even larger contact area may be provided. Thus, forces applied to the skin occurring during movement of the guard blade at haircutting operation may be suitably distributed over a larger contact area of the second guard tooth portion. The elevated portion may be provided at the 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 of the elevated portion may accordingly vary along the extension along the lateral direction. For instance, the elevation may increase from the distal end of the tip toward the first guard tooth portion.
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The invention further relates to a guard blade of a hair cutting device, wherein the guard blade comprises a 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 a cutter blade movably arranged in the housing of the haircutting device may accordingly allow for cutting or shearing off hair.
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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 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. It is noted that "top" and "bottom" are merely used 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, the 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 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 in 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, the guard blade comprises a plurality of adjacent guard teeth, wherein an intermediate reception cavity for receiving hair is defined between each of the plurality of adjacent guard 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. 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. For instance, adjacent guard teeth may form a U-shaped reception cavity or a V-shaped reception cavity. Thus, hair may be suitably guided to target portions of the guard teeth, where the cutting occurs.
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Other arbitrary forms are of course also conceivable dependent on the shape and arrangement of the adjacent guard teeth. The reception cavities should be generally large enough to receive one or more hairs.
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Corresponding reception cavities may also be provided between adjacent cutter teeth. The shapes of the guard teeth and the cutter teeth may 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 should be performed.
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In a preferred embodiment, one or more of the guard teeth of the guard blade protrude, in a lateral direction, beyond one or more cutter teeth of a 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 is prevented. Hence, 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 at the distal tips of the guard teeth instead of contacting the reciprocally moving cutter teeth of the cutter blade. Thus, injuries of the skin could be efficiently prevented.
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The present invention further relates to a hair cutting device comprising: a cutter blade movably connected to the hair cutting device, 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.
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The above explanations regarding any features and advantages concerning the guard tooth and the guard 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. In particular 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 comprising the guard blade having one or more of the guard tooth according to the present invention.
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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 guard blade may be connected to the haircutting device in an immovable manner. In another configuration, the guard blade may be connected to the haircutting device in a movable manner. The guard blade and the cutter blade may be connected to the haircutting device in a manner that a relative movement of the cutter blade and the guard blade could be achieved.
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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. As already explained above, it should be appreciated that the directions defined herein are only exemplarily denoted as "lateral", "width" and "height" to explain the relative arrangement and spatial relationships of the features and may also be denoted differently, as desired. Likewise, "top" and "bottom" are merely used to explain the relative arrangement of the features with respect to the haircutting device and is not construed to mean an absolute arrangements.
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The guard blade may be fixedly arranged in the housing, such that the reciprocal movement moves the cutter teeth relatively to the guard teeth. 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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In a preferred embodiment, the cutter blade comprises at least one cutter tooth extending from the cutter blade in a lateral direction and comprising a cutter tooth contact surface, wherein the cutter tooth contact surface is adapted to at least partially contact the cutter blade running surface during a relative movement of the cutter blade with respect to the guard blade.
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Thus, an efficient hair cutting may be achieved while the skin may be suitably protected during of the haircutting operation.
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The cutter blade running surface may be the surface adapted to face and contact at least partially a cutter tooth contact surface of a cutter tooth. That is, the cutter tooth 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 to enable a frictionless movement of the above 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 tooth contact surface and/or the 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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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 "59-1" or "59-2" refers to an instance of a device class that can be collectively referred to as device "59" and each of which can be generically referred to as device "59".
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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 an enlarged view of a guard blade according to an embodiment of the present invention;
- Fig. 3 schematically illustrates a side view of a guard tooth according to an embodiment of the present invention and a cutter tooth;
- Figs. 4A to 4C schematically illustrate different cross-sectional shapes of a guard tooth according to an embodiment of the present invention; and
- Fig. 5 schematically illustrates a front view of a guard blade 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 cutter blade 10 movably connected to the hair cutting device 100, a guard blade 20 connected to the hair cutting device 100, wherein the guard blade 20 is a guard blade 20 as described in this specification or wherein the guard blade 20 comprises at least one guard tooth 21 as described in this specification.
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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 71 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 the lateral direction L, and the reciprocal movement 71 occurs perpendicular thereto in a width direction W of the haircutting device 100. The haircutting device 100 is adapted to contact a skin of a user via the bottom side 7.
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In the depicted embodiment, the guard blade 20 is fixedly arranged in the housing 5, such that the reciprocal movement 71 of the cutter teeth 11 relatively to the guard teeth 21 is enabled. When the haircutting device 100 is moved in the lateral direction along the skin, hair to be cut could be captured between the cutter teeth and guard teeth and could be sheared off or cut by the reciprocal movement 71 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 the bottom side of the cutter blade 10 contacts the guard blade 20 (cf. Figs. 2-4). The cutter teeth 11 of the cutter blade 10 comprise a corresponding bottom cutter tooth contact surface 13 that contacts an upper surface of the guard teeth 21 during the reciprocal movement. Hair captured between the cutter teeth 11 and the guard teeth 21 could be accordingly sheared off.
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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, e.g. here in the lateral direction L. Accordingly, the skin contacts first a distal tip front surface 47 (cf. Fig. 5) of the guard teeth 21.
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One or more of the guard teeth 21 of the guard blade 20 protrude, in the lateral direction L, beyond one or more cutter teeth 11 of the cutter blade 10 movably arrangeable with respect to the guard blade 20. It is noted that not every single cutter tooth 11 and guard tooth 21 is labeled in the figure for representability reasons.
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The cutter blade 10 comprises at least one cutter tooth 11 extending from the cutter blade 10 in the lateral direction L and comprising the cutter tooth contact surface 13, wherein the cutter tooth contact surface 13 is adapted to at least partially contact the cutter blade running surface 23 during the relative movement 71 of the cutter blade 10 with respect to the guard blade 20. In other words, the cutter blade 10 is adapted to reciprocally move along the cutter blade running surface 23 of the guard blade 20.
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Fig. 2 illustrates an enlarged view of a guard blade 20 according to an embodiment of the present invention. Fig. 2 represents an enlarged excerpt of the guard blade 20 depicted in Fig. 1, however without depicting the further parts of the haircutting device 100. The guard blade 20 is the guard blade 20 of the hair cutting device 100, wherein the guard blade 20 comprises a base portion 27 and at least one guard tooth 21 extending in a lateral direction L therefrom, wherein the guard tooth 21 is a guard tooth 21 as described in this specification. 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 each of the plurality of adjacent guard teeth 21. 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. With reference to Fig. 1, it is noted that corresponding cavities are also formed by adjacent cutter teeth 11, which cavities of the guard teeth 21 and cutter teeth 11 may be aligned to form combined cavities for capturing hair. The guard teeth 21 may be equally distanced, as depicted in Figs. 1 and 2 or may be non-equally distanced in different embodiments. The base portion 27 may be 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 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 base portion 27, i.e. they are made of one piece.
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The guard tooth 21 for the guard blade 20 of the hair cutting device 100 is extending in a lateral direction L from the guard blade 20 and comprising a first guard tooth portion 25 connectable to the base portion 27 of the guard blade 20, and a second guard tooth portion 29 extending from the first guard tooth portion 25 in the lateral direction L. Further, in a view perpendicular to the lateral direction L, the first guard tooth portion 25 comprises a first guard tooth portion section 31 having an essentially non-rectangular cross-sectional shape 35 and the second guard tooth portion 29 comprises a second guard tooth portion section 33 having an essentially rectangular cross-sectional shape 37 (cf. in detail also Figs. 3 and 4). Accordingly, an increased distal contact surface of the guard teeth 21 at the first guard tooth portion section 31 could be provided, which reduces skin discomfort and injuries by distributing a pressure exerted to the skin contacting the guard teeth 21 to an increased area.
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The guard tooth 21 accordingly has a laterally arranged distal tip 45 for contacting skin during use of the haircutting device 100. The distal tip 45 comprises a distal tip front surface 47 having rounded edges 53, as will also be explained in greater detail with respect to Fig. 5. Further, the distal tip 45 comprises an elevated portion 63 extending above the cutter blade running surface 23, as will be explained in greater detail with respect to Fig. 3.
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The guard teeth 21 are suitable to generally prevent a contact of skin with the cutter teeth 11 arranged in the depicted embodiment above and laterally retracted from the distal tips 45 of the guard teeth 21 (cf. Figs. 1 and 3). Each guard tooth 21 includes the second guard tooth portion section 33 for protecting the skin and the first guard tooth portion section 31 at which the haircutting occurs. The second guard tooth portion 29 has a length 57 along the lateral direction L from a distal end 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. As depicted, the first guard tooth portion section 31 accordingly extends against the lateral direction L towards the base portion 27 with a first tooth portion length 56 from the second guard tooth portion 29.
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Furthermore, the cutter blade running surface 23 is arranged on a top side of the guard teeth 21. The cutter blade running surface 23 is accordingly formed such that a bottom side of a 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. Accordingly, hair captured in the reception cavities 69 could be properly cut or sheared off.
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Fig. 3 schematically illustrates a side view of a guard tooth 21 according to an embodiment of the present invention and a corresponding cutter tooth 11 provided above the guard tooth 21. The guard tooth 21 comprises at its top surface the cutter blade running surface 23 which contacts the cutter tooth contact surface 13 arranged at the bottom surface of the cutter tooth 11. The second guard tooth portion section 33 is formed at the distal tip 45 of the guard tooth 21 for contacting skin or hair, and the distal tip 45 comprises, in a view perpendicular to the lateral direction L, the essentially rectangular cross-sectional shaped distal tip front surface 47.
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As depicted, the distal tip 45 of the guard tooth 21 is essentially rectangularly formed and has further rounded edges 53 (cf. also Fig. 5). 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. The rounded edges 53 have a curvature radius R, which is exemplarily depicted for the bottom rounded edge 53. It is apparent, that also the other rounded edges 53 may comprise a corresponding curvature radius R that may be the same or different to the curvature radius R depicted for the bottom rounded edge 53. The rounded edges 53 are provided in the width direction W, the height direction H and the lateral direction L. However, in different embodiments, the rounded edges 53 may only be provided at one, two or three sides. In different embodiments, no rounded edges 53 are provided.
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The second guard tooth portion section 33 comprises an elevated portion 63, wherein the elevated portion 63 comprises a height 65 extending above a height 67 of the first guard tooth portion 25 such that a cross-sectional area of the second guard tooth portion section 33 is larger than a cross-sectional area of the first guard tooth portion section 31 adjacent to the second guard tooth portion section 33. The differences between the respective cross-sectional areas are explained in detail with respect to Figs. 4A to 4C. Generally, a cross-sectional surface of the guard tooth 21 is increased at the second guard tooth portion compared to an adjacently arranged first guard tooth portion 25. The first guard tooth portion 31 may extend from the second guard tooth portion 29 with a first tooth portion length 56 against the lateral direction L toward the base portion 27 (not depicted, cf. Fig. 2) of the guard blade 20. The cutter tooth 11 is arranged essentially at the first guard tooth portion 25, and in particular at the first guard tooth portion section 31, where the cutting occurs.
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Figs. 4A to 4C schematically illustrate different cross-sectional shapes of a guard tooth 21 according to an embodiment of the present invention. An essentially rectangular cross-sectional shape 37 of a second guard tooth portion section 33 is depicted in Fig. 4A. The essentially rectangular cross-sectional shape 37 of the second guard tooth portion section 33 comprises a maximum area in a range of 0.2 mm2 to 1 mm2, preferably in a range of 0.3 mm2 to 0.46 mm2 and more preferably of about 0.39 mm2 In other configurations, the maximum area may however also be larger or smaller, as desired. The essentially rectangular cross-sectional shape 37 comprises four essentially 90° first guard tooth portion section angles 41 forming a rectangle. In the depicted embodiment, the rectangle is formed as a square. However, also different rectangular forms may be provided.
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Figs. 4B and 4C each show an essentially non-rectangular cross-sectional shape 35 provided at the first guard tooth portion section 31. It is apparent, that the area of the essentially rectangular cross-sectional shape 37 depicted in Fig. 4A is larger compared to the area of the essentially non-rectangular cross-sectional shapes shown in Figs. 4B and 4C. In the depicted embodiment, the essentially non-rectangular cross-sectional shape 35 of the first guard tooth portion section 31 forms a trapezoid comprising two unevenly long parallel legs 59 and two inclined legs 61 connecting the two unevenly long parallel legs 59, wherein the first guard tooth portion section 31 comprises the cutter blade running surface 23 formed by the longer one 59-1 of the unevenly long parallel legs 59, wherein the cutter blade running surface 23 is adapted to face the cutter blade 10 arrangeable above the guard blade 20 for at least partially contacting the cutter blade running surface 23. Thus, two acute second guard tooth portion section angles 43 are provided at the top side of the first guard tooth portion section 31, which enables an improved hair cutting at the cutter blade running surface 23.
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The angle 43 between the longer one 59-1 of the parallel legs 59 and one or more of the two inclined legs 61 is between 45 and 80 degrees. A corresponding angle between the shorter one 59-2 of the parallel legs 59 and one or more of the two inclined legs 61 is accordingly larger than 90°.
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Fig. 4C shows another embodiment, wherein the first guard tooth portion section 31 additionally comprises cutting features 39 arranged at the top side of the guard tooth 21 forming part of the cutter blade running surface 23. These cutting features 39 may also be integrally formed with the first guard tooth portion 25 of the guard tooth 21.
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It is noted that in Figs. 4A to 4C only simplified representations of the cross-sectional areas are presented, i.e. without showing the rounded edges 53 depicted for instance in the embodiments shown in Figs. 1 to 3 and 5. However, it will be understood that one or more of the corners and edges of one or more of the depicted cross-sectional shapes may accordingly include respective additional roundings. However, in other configurations, also no roundings may be provided.
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Fig. 5 schematically illustrates a front view of a guard blade 20 according to an embodiment of the present invention. The figure depicts two guard teeth 21, each comprising a distal tip 45 extending from the guard blade in the lateral direction L forming the outermost portions thereof. The distal tip 45 comprises the distal tip front surface 47. The guard teeth 21 are distanced from each other by a tooth pitch 55. Between the guard teeth 21, a reception cavity 69 is formed for capturing hair to be cut.
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As depicted, the essentially rectangular cross-sectional shaped distal tip front surface 47 comprises round edges 53 with a curvature radius R in a range 0.05 mm to 1 mm, preferably in a range of 0.1 mm to 0.4 mm and more preferably of about 0.3 mm. In other configurations, the curvature radius may however also be larger or smaller, as desired. The rounded edges 53 are provided at the corners of the rectangular cross-sectional shape, e.g. the exemplary shape described with respect to Fig. 4A. As already explained above roundings are provided in the width direction W, the height direction H and the lateral direction L. Accordingly, the roundings overlap at the outermost distal portion of the distal tip front surface 47 forming different roundings at the corners, referenced with 53-1, compared to the roundings along the edges, referenced with 53-2. Thus, the distal tip front surface 47 may protrude toward the lateral direction. Roundings with the same or different curvature radii may be provided as desired. In some configurations, the roundings may be only provided at one or certain sides or may be even completely omitted.
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The second guard tooth portion section 33 comprises a width 49 perpendicular to the lateral direction L in a range of 0.2 mm to 1 mm, preferably in a range of 0.3 mm to 0.8 mm and more preferably in a range of 0.5 mm to 0.6 mm. Further, the second guard tooth portion section 33 comprises a height 51 perpendicular to the lateral direction L 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. Thus, a respective mechanical stability of the guard tooth 21 in the height direction H and/or in the width direction W may be achieved. However, in other configurations, the width 49 and/or height 51 may also be 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 tooth contact surface
- 20
- guard blade
- 21
- guard tooth
- 23
- cutter blade running surface
- 25
- first guard tooth portion
- 27
- base portion
- 29
- second guard tooth portion
- 31
- first guard tooth portion section
- 33
- second guard tooth portion section
- 35
- non-rectangular cross-sectional shape
- 37
- rectangular cross-sectional shape
- 39
- cutting features
- 41
- first guard tooth portion section angle
- 43
- second guard tooth portion section angle
- 45
- distal tip
- 47
- distal tip front surface
- 49
- guard tooth width
- 51
- guard tooth height
- 53
- rounded edges
- 55
- tooth pitch
- 56
- first tooth portion length
- 57
- second tooth portion length
- 59
- parallel trapezoid leg
- 61
- inclined trapezoid leg
- 63
- elevated portion
- 65
- elevated portion height
- 67
- first guard tooth portion height
- 69
- reception cavity
- 71
- cutter blade movement
- 100
- hair cutting device
- L
- lateral direction
- H
- height direction
- W
- width direction
- R
- curvature radius