BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
FIG. 1 is an external view of a rotary shaver according to one embodiment of the present invention;
FIG. 2 is a perspective view of an inner cutter for a rotary shaver according to one embodiment of the present invention;
FIG. 3 is a front elevational view thereof;
FIG. 4 is an enlarged explanatory diagram of Portion A in FIG. 2;
FIG. 5 is a graph showing the results of durability tests on the inner cutter for a rotary shaver according to the embodiment of the present invention and on the conventional inner cutters for rotary shavers;
FIG. 6A is an explanatory diagram showing the shape of a conventional inner cutter of the samples A and B used in the durability tests, FIG. 6B being a front view thereof;
FIG. 7A is an explanatory diagram showing the shape of a conventional inner cutter in the samples C and D used in the durability tests, FIG. 7B being a front view thereof;
FIG. 8 is an explanatory diagram showing the shape of an inner cutter (blade support and cutter blade) of another embodiment of the present invention;
FIG. 9 is an explanatory diagram showing the shape of an inner cutter (blade support and cutter blade) of still another embodiment of the present invention;
FIG. 10 is an explanatory diagram showing the shape of an inner cutter (blade support and cutter blade) of still another embodiment of the present invention;
FIG. 11 is an explanatory diagram showing the shape of an inner cutter (blade support and cutter blade) of still another embodiment of the present invention;
FIG. 12 is an explanatory diagram showing the shape of an inner cutter (blade support and cutter blade) of still another embodiment of the present invention;
FIG. 13 is an explanatory diagram showing the shape of an inner cutter (blade support and cutter blade) of still another embodiment of the present invention;
FIG. 14 is an explanatory diagram showing the shape of an inner cutter (blade support and cutter blade) of still another embodiment of the present invention; and
FIG. 15 is an explanatory diagram of the condition (relation) of a blackboard and a chalk when drawing a line on a blackboard with a chalk.
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 shows a rotary shaver according to the embodiments of the present invention. FIG. 2 is a perspective view of the inner cutter for a rotary shaver of one embodiment. FIG. 3 is a front view thereof. FIG. 4 is an enlarged explanatory diagram of Portion A in FIG. 2.
As seen from FIG. 1, the rotary shaver 100 is an electrically chargeable type shaver that includes a chargeable battery which is a power supply (power source) and a motor which is a drive unit housed inside the frame body 40 of the shaver (and thus neither the chargeable battery or the motor are shown in FIG. 1). At the top of the shaver frame body 40, three inner cutters 10 (see FIGS. 2 to 4), which are rotationally driven in linkage with the output shaft (not shown) of the motor, and three outer cutters 30, which are for cutting hair in conjunction with the inner cutters 10, are provided such that they, respectively, are detachable with respect to the shaver frame body 40. In the shown embodiment, three pairs of outer and inner cutters are provided in the shaver 100 (or in the shaver frame body 40) so as to be arranged in a triangular shape; and the present invention is applicable to rotary shavers with different number(s) of outer and inner cutters than the shown embodiment.
The inner cutter 10 for the rotary shaver 10 (hereinafter sometimes referred to simply as the “inner cutter 10”) shown in FIGS. 2 to 4 is formed of thin stainless steel sheet. The inner cutter 10 is comprised of an inner cutter main body 12 having underneath an inner cutter guide 13 which is connected to the output shaft of the drive unit housed in the shaver frame body of the rotary shaver 100, a plurality of blade supports 14 raised from the inner cutter main body 12, and a cutter blade 16 formed at the tip end portion (or the upper end portion in the drawings) of each one of the blade supports 14.
The cutter blades 16 in this embodiment are provided in two rows, on the inner circumference side and on the outer circumferential side, in the radial direction of the inner cutter main body 12. The cutter blades 16 slide, with a prescribed frictional force, against inner surface of the outer cutter 30, in inner circumferential side slits 32a and outer circumferential side slit 32b in each one of the outer cutters 30, which are shown in FIG. 1. Hair entered through the slits 32a and 32b into the interior of the outer cutter 30 is cut by the cutter blades 16 (of the rotating inner cutter 10) that slide over the inner surfaces of the portions between the slits 32a and 32b.
The blade supports 14 are formed at equal intervals in the direction of rotation of the inner cutter 10 in the inner cutter main body 12. The blade supports 14 are formed by being cut from the inner cutter main body 12. The blade supports 14, after being cut from the inner cutter main body 12, are bent and raised on the inner cutter main body 12 so as to be inclined in a direction opposite from the direction of rotation of the inner cutter 10 (the rotational direction of the inner cutter 10 is shown by arrow R in FIG. 4).
As shown in FIG. 4, the cutter blades 16 are formed, as described above, at the tip end portions 14b of the blade supports 14. The cutter blades 16 are formed so as to be inclined in a direction opposite from the direction of inclination of the blade supports 14. In other words, the cutter blades 16 are formed so that they are, from the points of the tip end portions 14b of the blade supports 14, inclined forward in the direction of rotation of the inner cutter 10 shown by arrows R in FIG. 3. More specifically, the blade supports 14 are raised so as to incline in the direction opposite from the rotational direction R of the inner cutter 10, and the cutter blades 16 are formed on the blade supports so as to be inclined into the rotational direction R of the inner cutter 10.
In this structure, the blade supports 14 and the cutter blades 16 are formed so as to take a substantially inverted L shape (or in a “>” shape as seen from drawings). Causing the cutter blades 16 to be inclined in the direction of rotation of the inner cutter 10 in this manner allows the feel of the shave to be enhanced, even with a thin-material structure (or even if the inner cutter main body 12, the blade supports 14, and the cutter blades 16 are made of a thin metal material of, for instance, 0.3 mm), and thus it is advantageous. The blade supports 14 and the cutter blades 16 in the shown embodiment are formed integrally, and they can be formed by press machining.
Furthermore, as seen from FIG. 4, the position X of each one of the raised portions 14a of each one of the blade supports 14 that is the portion of the blade support 14 raised up from the inner cutter main body 12 is set to be located forward in the direction of rotation of the inner cutter 10 relative to the position Y of the reverse bent portion 14c which is substantially inverted L shape formed by the cutter blade 16 and (the tip end portion 14b of) the blade support 14. Furthermore, the position X of each one of the raised portions 14a is set to be located forward in the direction of rotation of the inner cutter 10 relative to a position Z where the leading tip end (blade tip end or blade's forward edge) 16a of the cutter blade 16 is located. In other words, the leading edge 16a of each cutter blade 16 is behind the raised portion 14a of the blade support with reference to the rotational direction R of the inner cutter 10.
By providing each of the raised portions 14a, support tip end portions 14b, bent portions 14c, and leading tip ends (blade tip end or blade's forward edge) 16a so that their positional relationships are as described above, an action in which the cutter blades 16 pull away from the outer cutter when the inner cutter 10 is rotated occurs; and as a result, abnormal sliding between the cutter blades 16 and the outer cutter is prevented assuredly. Accordingly, anything that would adversely affect the feel of the shave, such as wear in the cutter blades 16 and outer cutter 30 and/or blade breakage is prevented.
FIG. 5 is a graph representing the results of durability tests on the inner cutter for a rotary shaver in the shown embodiment and inner cutter for rotary shavers of conventional art.
In conducting these durability tests, inner cutters and outer cutters, after being cleaned in a trichloroethylene ultrasonic cleaning machine, and after verification that they had been degreased, were connected to the output shaft (rotating shaft) of rotary shavers having a common configuration. In these durability tests, the inner cutters on rotary shavers are rotated for three minutes and then the rotation is stopped for three minutes, and this action was performed repeatedly. These on-off actions were repeated until the cumulative on time of the on-off actions reached 100 hours.
In the durability tests, when damage to an outer cutter (such as a crack developing in the outer cutter, and the outer cutter breakage) occurred, or when abnormal wear developed in the slide surfaces of the outer cutter and inner cutter, an NG (no good) judgment was made. When, on the other hand, a cumulative on time for the on-off action of 100 hours was reached without any damage occurring in the outer cutter or any abnormal wear occurring in the sliding surfaces of the outer cutter and inner cutter, an OK judgment was made. Outer cutter damage checks were performed every six minutes (after every on-off cycle) by microscopic examination at a magnification power of 20×.
Three of each sample were tested under the same conditions. In cases an NG judgment is made, the average value (in hours) of the cumulative time of three samples is taken and indicated by “ave” (average).
In the inner cutters in samples A and B in FIG. 5, the cutter blades 16 are formed at the tip ends of blade supports 14 that are, as shown in FIGS. 6A and 6B, raised from the inner cutter main body 12 so that the tip end portions of the blade supports 14 are inclined forward in the rotational direction R of the inner cutters. The blade supports 14 and the cutter blades 16 are, as seen from FIGS. 6A and 6B, formed in a straight line. The sheet thicknesses of the blade supports 14 in samples A and B are, respectively, 0.5 mm and 0.3 mm.
Sample A was given an NG judgment, with an average value of cumulative time being 20.2 hours. Sample B was also given an NG judgment, with an average value of cumulative time being 6.3 hours.
In the inner cutters in samples C and D in FIG. 5, the cutter blades 16 are, as shown in FIGS. 7A and 7B, formed at the tip ends of blade supports 14 raised from the inner cutter main body 12 so that the tip end portions are inclined forward in the rotational direction R of the inner cutters. In the inner cutters 10 of samples C and D also, the blade supports 14 and the cutter blades 16 are formed in a straight line. The sheet thicknesses of the blade supports 14 in samples C and D are, respectively, 0.5 mm and 0.3 mm. In the respective inner cutter guides 13 of the sample inner cutters C and D, inner cutter guide swing-prevention members 20 are provided for supporting the lower surface of the inner cutter main body 12.
Sample C was given an OK judgment. Sample D, however, was given an NG judgment, with an average value of cumulative time being 5.8 hours.
The differences between sample A and sample C, and, likewise, between sample B and sample D, are, in both cases, the difference of providing or not providing the inner cutter guide swing-preventing members 20. Looking at the results of the durability tests for sample A and sample C, it can be seen that providing the inner cutter guide swing-preventing members 20 is beneficial; however, looking at the results of the durability tests for sample B and sample D, there is no benefit in providing the inner cutter guide swing-preventing members 20.
As seen from the above, it is evident that, when the sheet thickness of the inner cutter 10 is thin, even when the inner cutter guide swing-preventing members 20 are provided for the inner cutters 10, minute vibrations in the inner cutters 10 are not avoidable.
The inner cutters 10 in samples E and F in FIG. 5 have the same shape as shown in FIG. 2 to 4 and described for the embodiment above. As seen from FIG. 5, the results of the durability tests were that OK judgments were given to both samples E and F.
As seen from the durability test results described above, it is clear that by adopting the inner cutter shape of the present invention, inner cutters have satisfactory durability, even when the sheet thickness of the blade supports 14 (that is, of the inner cutter main body 12 and cutter blades 16) is given a thin-material structure (having a 0.3 mm thickness). In addition, even without inner cutter guide swing-preventing members, the chalk phenomenon between the cutter blade 16 and the outer cutter is prevented, so that the quality of the inner cutter 10 is enhanced at low cost.
The inner cutter for a rotary shaver according to the present invention is not limited to or by the embodiment described above; and, needless to say, such inner cutters as those in which various modifications are made within the scope not altering the characteristics of the invention are within the technical scope of the present invention.
For example, in the shown embodiment, the inner cutter 10 (or the blade support 14 and cutter blade) is in an inverted L (or “>”) shape as shown in, for instance, FIG. 2, but the inner cutter 10 of the present invention is not limited to or by this shape.
More specifically, the inner cutter 10 can be formed so that, as shown in FIG. 8, the blade support 14 is raised or erected perpendicular to the inner cutter main body 12 and bent in the direction opposite from the inner cutter rotating direction R, and then the blade tip end of the cutter blade 16 at the tip end portion 14b of the blade support 14 is oriented in the direction of rotation of the inner cutter 10.
It is also possible, as shown in FIG. 9, that the blade support 14 is raised from the inner cutter main body 12 and inclined backward in the rotational direction R of the inner cutter 10 (or inclined in the opposite direction to the rotational direction R of the inner cutter 10), and then the thickness of the material midway along the blade support 14 is made smaller by press machining or the like so as effect a mode in which the elasticity is adjusted. The blade tip of the cutter blade 16 at the tip end portion 14b of the blade support 14 is of course provided so that it is oriented in the direction of rotation of the inner cutter 10.
In this inner cutter shown in FIG. 9, the (size of the) angle β between the blade support 14 and the cutter blade 16 and the (size of the) angle γ between the blade support 14 and the inner cutter main body 12 are not particularly limited, and such angles can be freely set insofar as it lies within the range that satisfies the present invention.
Furthermore, in the present invention, it is also possible, as shown in FIG. 10 and FIG. 11, to provide bent portions 14c at a plurality of locations in each one of the blade supports 14 that are raised from the inner cutter main body 12 and inclined backward in the direction of rotation of the inner cutter (or in the direction opposite from the rotational direction R of the inner cutter). In these structures, the strength and elasticity of the blade supports 14 is adjusted to a desired condition.
Furthermore, as shown in each of FIGS. 12 and 13, the cutter blade 16 of the inner cutter can be formed in a circular arc shape at the tip end portion of the blade support 14 that is raised from the inner cutter main body 12. This is a mode in which the bent portion 14c is formed midway along the blade support 14 which is raised from the inner cutter main body 12, and then the portion between the bent portion 14c and the cutter blade 16 is formed in a circular arc to form a curved shape. In this inner cutter as well, needless to say, the tip end (blade tip portion) of the cutter blade 16 is oriented in the rotational direction R of the inner cutter 10. The blade support 14 raised from the inner cutter main body 12 needs only to be such that the blade support 14 is not inclined forward in the direction of rotation of the inner cutter 10 (or in the same direction as the inner cutter rotational direction R), and, needless to say, it is also possible to erect the blade support 14 perpendicularly from the inner cutter main body 12 and the curved blade support 14 is formed thereon as shown in FIG. 12.
In the structure of FIG. 14, the entire shape of the blade support 14 is formed in a circular arc, and the cutter blade 16 is provided so as to coincide with the linearity or the curvature of the entire shape of the blade support 14, so that the blade support 14 and the cutter blade 16 assume the same circular arc or curved shape. In this curved blade support and cutter blade structure as well, needless to say, the position of the raised portion 14a of the blade support 14 is set at a position which is more forward in the rotational direction R of the inner cutter 10 than the position of the leading edge (blade tip end or blade's forward edge) of the cutter blade 16.
In the inner cutters 10 described above, the blade supports 14 are raised (or erected) in a plurality of rows in the radial direction in the inner cutter main body 12; however, it is not absolutely necessary that the number of raised portions (blades supports) on the outer circumferential side coincide with the number of raised portions (blades supports) on the inner circumferential side, and thus the number of raised portions on the inner circumferential side and the outer circumferential side can be different.
Moreover, the elements in the inner cutter shapes (blade support and cutter blade shapes) described in the above can be indeed taken and freely combined to form an inner cutter.
Patent Application
20080028618
