Patent Application
20120210586
The present invention relates to a hair cutting device. Such a hair cutting device is for example a razor, in particular a blade shaver or an electrical shaving device.
US 2005198843 discloses a razor including a linkage mechanism. The linkage mechanism has been configured for a razor having a head carrying at least one razor blade mounted for a large extent of rocking about a virtual pivot axis. The virtual pivot axis remains nearly static during pivoting. The linkage mechanism is attached to a handle and has five links, which include a pair of spaced support arms pivoted to the head at first and second pivot axes. The first and second pivot axes being spaced apart by a first distance. A first transverse link member is pivoted on the body for rotation about a third axis and pivoted on each of the support arms, a fourth and fifth pivot axes are spaced apart by a second distance less than the first distance, and second and third transverse link members are pivoted on the handle at respective first ends thereof and pivoted on respective second ends thereof to respective first ends thereof and pivoted on respective second ends thereof to respective ones of the support arms at sixth and seventh pivot axes spaced apart by a third distance. The first, second, third, fourth, fifth, sixth and seventh axes are mutually parallel.
One drawback of the referred razor is that it has a complex assembly. The complex assembly is vulnerable to damages during use. The mechanism has a lot of pivoting components which may fail due to contamination or wear. Due to the amount of components, the assembly is relatively difficult to manufacture, which leads to undesired high costs.
It would be desirable to at least partially eliminate the above drawbacks and/or to provide a usable alternative. It would also be desirable to provide a hair cutting device having a pivoting mechanism which provides a virtual pivoting axis near or at a user's skin level.
The hair cutting device according to the invention comprises a base portion, a working head and at least one pivoting mechanism. In particular, the hair cutting device is a shaving device. The base portion is configured to be gripped by a user and may include a grip for holding the device by hand. The working head is configured to hold at least one cutter and may e.g. be a razor blade cartridge. The pivoting mechanism is configured to pivotally connect the base portion to the working head and is configured to provide an outer virtual pivot axis.
In particular, the pivoting mechanism may also be called a link mechanism or more in particular a rolling link mechanism. The pivoting mechanism comprises a contact body, a counter body and a holding unit. The contact body is connected to the base portion. The counter body is connected to the working head. The contact body has an outer contact surface. The counter body has an outer running surface. The holding unit guides the contact body over a stroke along the running surface of the counter body. The holding unit is configured to hold the contact surface of the contact body such that, during use, the contact body runs along the running surface of the counter body. The holding unit couples the contact body to the counter body. The contact body may roll or slide along the running surface. The contact surface of the contact body may be directly in contact with the running surface of the counter body. The holding unit is spring-loaded for returning the contact body to an initial position along the running surface. The holding unit comprises at least one elongated connecting component which extends at least partially tangentially along the running surface. At least one end of the connecting component may be fixed to the running surface. By virtue thereof, a compact configuration of the pivoting mechanism may be obtained. During operation, the pivoting mechanism may provide low friction forces which may keep the pivoting mechanism substantially free of hysteresis. Advantageously, the spring load may provide a torque to the pivoting mechanism which may be necessary for the working process corresponding with the hair cutting device, e.g. a shaving process.
Advantageously, the pivoting mechanism provides an outer virtual pivot point, which position may be defined by the running surface of the counter body. Advantageously, the virtual pivot point is positioned external to the pivoting mechanism. For skin care hair cutting devices it may be desired to position a pivot point near or at skin level at a lower region of the working head. To obtain such an arrangement, preferably, the running surface of the counter body which is positioned at an upper region of the working head is convex. By virtue thereof, the virtual pivot point may be positioned below the counter body in a center of the convex running surface. Advantageously, the handheld device according to the invention comprises a pivoting mechanism which may provide a position of the virtual pivot point even outside the working head e.g. at skin level or at least close to skin level, i.e. just above or just below a skin surface. Improved skin contour following properties may be achieved when a working head, e.g. a razor blade cartridge, is connected by the pivoting mechanism according to the invention to the base portion. Additionally, the hair cutting device according to the invention may be less susceptible to wear or damage. Components of the pivoting mechanism advantageously may have a relatively robust configuration.
In an embodiment of the hair cutting device according to the invention the contact body has a cylindrical contact surface including a constant radius and the counter body has a convex running surface also including a constant radius. This may result in a static position of the virtual pivot point in the center of the running surface. During shaving, when the working head contacts the skin, the base portion may make a pivoting movement with respect to the working head. Advantageously, due to the presence of the pivoting mechanism according to the invention, the risk of an unexpected angular translation of the working head with respect to the skin during the pivoting movement may be decreased. Thus, the risk of injuries may be decreased.
In an embodiment of the haircutting device according to the invention, the contact body is a roller including an outer roller surface. The roller is connected to the base portion. In particular, the roller is rotatably connected to the base portion. The roller may have an inner axis of rotation. The counter body has a running surface interacting with the roller surface. The counter body is connected to the working head. In use, the roller may roll and run over the running surface of the counter body. In particular, the roller rolls substantially slip-free along the running surface. Advantageously, the pivoting mechanism including the roller may operate very lightly. The roller may travel over a stroke along the running surface from a start position to an end position. In use, the axis of rotation of the roller may be displaced relative to the counter body. The holding unit connects the roller to the counter body and guides the roller during the displacement over the running surface. The holding unit connects the roller in a radial direction to the counter body.
In an embodiment of the hair cutting device according to the invention, the running surface of the counter body has various radii. The running surface may be subdivided into running surface sections. Each subsequent running surface section may have another radius or another arbitrary contour. A running surface section may have an infinite radius, which may make the running surface section flat. Preferably, the running surface of the counter body has a convex contour. Advantageously, a running surface comprising at least two different running surface sections may define a virtual pivot path. During a rolling movement of the roller over the running surface, the virtual pivot point may move over the virtual pivot path. The pivot point may e.g. translate along a straight line during the pivoting movement. By virtue thereof, advantageously, the running surface may be adapted optimally to requirements of a working process corresponding to the hair cutting device. In particular for a shaving device it may be desired to include a virtual pivot path to obtain improved skin contour properties in a neck zone.
In an embodiment of the hair cutting device according to the invention, at least one of the running surface and the roller surface comprises a groove which extends in a length direction. Advantageously, the groove may collect any contamination which could disturb the proper running of the contact body. Advantageously, one of the running or roller surface is provided with a complementary organ which may fit into the groove. By virtue thereof, the roller may be guided along the running surface. Advantageously, the roller may remain in a transversal position with respect the counter body. Transversal forces acting on the pivoting mechanism may be overcome by enclosing the complementary organs in the groove.
In an embodiment of the hair cutting device according to the invention, the holding unit is a linking bar. The linking bar may be longitudinal having a first and a second end. The first end may be fixed to the contact body, and the second end may be fixed to the counter body. Advantageously, the linking bar guides the contact body along the running surface.
In an embodiment of the hair cutting device according to the invention, the holding unit may e.g. be a wire or a thin strip. The holding unit may be a metal strip. The holding unit may be elongated having a first and a second end. The first end of the holding unit may be fixed to a first position on the running surface and the second end of the holding unit may be fixed to a second position on the running surface. The contact body may be movable in between the first and the second position on the running surface. The holding unit may be flexible in that during use the holding unit may be elastically deformed due to occurring forces. The holding unit may e.g. be flexible in that the holding unit bends during a movement of the roller. Advantageously, the flexible holding unit may keep the roller in contact with the running surface, e.g. by exerting a pressing force.
In a further embodiment of the hair cutting device according to the invention, the holding unit may have a fixation point at an intermediate partition to fix the holding unit to the contact body, in particular the roller. In particular, the holding unit extends along the running surface, wherein the intermediate partition is wound at least partially along the roller surface. The holding unit may be subdivided by the fixation point into a first and a second section. When the roller runs over the running surface, the first section of the holding unit unwinds while the second section winds up to the roller. Advantageously, the fixing of the intermediate partition to the roller may prevent slip of the roller with respect to the running surface. Since the roller is fixed at both sides by the holding unit, slip may be prevented in both directions along the running surface. Advantageously, the roller may be locked to the running surface of the counter body and only a pure rolling movement may be allowed.
In a further embodiment of the hair cutting device according to the invention, the first and the second section of the holding unit may be formed by a first and a second connecting component. Instead of a one-piece holding unit, the holding unit may comprise at least two connecting components. The connecting component may be a wire or a strip. The holding unit may e.g. comprise a pair of wires. The pair of wires may include a first and a second wire. The wires may be fixed at one end to the running surface and at an opposite end to the roller surface. Preferably, from the fixation point on the roller, the second wire may be arranged as a prolongation of the first wire. The first and the second wire may be wound crosswise along the roller surface, such that always one of the wires unwinds during a movement of the roller. Advantageously, the connecting component provides a simple configuration to keep the roller on the running surface and to prevent slip of the roller.
In an embodiment of the hair cutting device according to the invention, the holding unit and the contact body are formed in one piece with each other. The holding unit may be incorporated into the contact body. The holding unit may e.g. be defined by two wires which may be moulded together with the contact body. The assembly of the holding unit and the roller may advantageously be relatively simply manufactured by injection moulding.
In an embodiment of the hair cutting device according to the invention, the pivoting mechanism is spring-loaded. An additional spring member may be provided to return the contact body to an initial position. Advantageously, the spring load may provide a torque which may be necessary for the working process corresponding with the hair cutting device, e.g. a shaving process. Preferably, the spring member is a leaf spring. Advantageously, the leaf spring may impose a mechanical torque on the pivot axis to keep the blade cartridge in position so as to obtain an appropriate contour-following action.
In an advantageous embodiment according to the invention, the spring member may be integrated in the holding unit. By virtue thereof, the holding unit may be resilient. The holding unit may comprise the leaf spring. The leaf spring may be fixed at one end to the running surface and at the other end to the roller surface. During use, a part of the leaf spring may be disposed along the running surface, wherein a remaining part may be wound along the roller surface. As a result, the leaf spring prevents the roller from slipping, in one direction, away from the spring leaf in a length direction along the running surface, and at the same time produces a spring load to return the roller to its initial position. Thus, advantageously, a pretension is incorporated in the holding unit.
In an embodiment of the hair cutting device according to the invention, the spring leaf has a decreasing cross section in a length direction. The spring leaf may be inclined, e.g. conical. Advantageously, the spring leaf includes a constant spring energy when the spring leaf is unwound. During the pivoting movement, the spring leaf may generate a substantially constant force, which may force the contact body back to the initial position.
In an embodiment of the hair cutting device according to the invention, the hair cutting device comprises an assembly of at least three pivoting mechanisms. A first pivoting mechanism may have a first counter body and a first contact body. A second pivoting mechanism may have a second counter body and a second contact body. The first and the second contact body may be rotatably connected to the base portion. The base portion may comprise a grip; the base portion may e.g. be configured as a handle. The handle may be fork-shaped, wherein the first and the second contact body may be connected to the distal end of the handle. The first and the second contact body may be aligned for defining a first pivot axis. The first and the second pivoting mechanism leave two degrees of freedom for moving the base portion with respect to the working head. A first degree of freedom is determined by the first and the second aligned running surfaces. The base portion may translate along the working head. The second degree of freedom of movement is determined by the aligned first and second contact bodies. The base portion may rotate about an axis defined by a center line through the first and the second contact body. The third pivoting mechanism having a third contact body and a third counter body is arranged to compensate the second degree of freedom. The third contact body is staggered with respect to the first and the second contact body. By virtue thereof, a rotation about the pivot axis defined by the first and the second contact body is eliminated. A pivoting mechanism assembly results having one degree of freedom including a pivot axis determined by the aligned running surfaces.
In an embodiment of the hair cutting device according to the invention, the hair cutting device comprises a stacked pair of assemblies of pivoting mechanisms. Each pivoting mechanism assembly has at least three pivoting mechanisms, which are arranged as described above to define one virtual pivot axis. The stacked assemblies together may define two perpendicularly oriented virtual pivot axes. The two axes provide two degrees of freedom to a connected working head. By virtue thereof, advantageously, the working head may be connected by a virtual ball joint defined by the two virtual axes.
In an embodiment of the hair cutting device according to the invention, the hair cutting device is a shaving device. In particular, the working head is a shaving head. The shaving device may be of any kind. The shaving device may be an electrical shaving device, a single-use shaving device, a blade shaver, a vibra-shaver etc.
Further preferred embodiments are defined in the subclaims.
The invention will be explained in more detail with reference to the appended drawings. The drawings show a practical embodiment according to the invention, which may not be interpreted as limiting the scope of the invention. Specific features may also be considered apart from the shown embodiment and may be taken into account in a broader context as a characterizing feature, not only for the shown embodiment but as a common feature for all embodiments falling within the scope of the appended claims, in which:
The pivoting mechanism 10 has a roller 11 which is rotatably connected to the base portion 20. The roller 11 has a roller surface 12. The roller surface may be circular. The roller 11 is movable about a counter body 13 which has a running surface 14. The counter body is arranged aside the roller. Preferably, the running surface is circular. The running surface may have a constant radius. The radius of the running surface determines a fixed pivot point 19 for the rolling movement of the roller 11. In
As further shown in
Thus, according to the invention a hair cutting device is provided including an improved suspension of a working head relative to a base portion. In particular, a more comfortable hair cutting device is provided having improved skin contour following properties.
The terms “a” or “an”, as used herein, are defined as one or more than one. The term “plurality”, as used herein, is defined as two or more than two. The term “another”, as used herein, is defined as at least a second or more. The terms “including” and/or “having”, as used herein, are defined as comprising (i.e., open language, not excluding other elements or steps). Any reference signs in the claims should not be construed as limiting the scope of the claims or the invention. 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.
Although this invention has been shown and described with respect to detailed embodiments thereof, it will be understood by those of skill in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. For example, the shown spring leaf of the holding unit may have a decreasing cross section in a length direction. In another variant, running surfaces may have a non-constant radius. In an embodiment of a hair cutting device having an assembly of pivoting mechanisms, a common centrally located spring may be provided to obtain a spring-loaded assembly. The common spring may be located external to a pivoting mechanism. One pivoting mechanism provided with a spring may be sufficient to achieve also a spring load on other pivoting mechanisms of the hair cutting device. As a result, it may not be necessary to provide an individual spring for each individual pivoting mechanism. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed in the above detailed description, but that the invention will include all embodiments falling within the scope of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 09175748.4 | Nov 2009 | EP | regional |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/IB2010/055030 | 11/5/2010 | WO | 00 | 4/13/2012 |
