JPH0441638B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a reciprocating electric shaver blade.

(Background technology) The inner blade of a reciprocating electric shaver is generally formed into a semicircular cross section, but since the beard enters the blade hole of the outer blade in a lying state, there is a gap between the blade hole and the blade hole. The problem was that it was difficult to catch the beard because it would get stuck on the bar between the two, and it was also difficult to shave under the chin. In response to this, a tool having a tapered inner cutter was proposed as shown in Japanese Patent Application Laid-Open No. 136976/1983.

This is done by reducing the radius of curvature at the tip of the inner cutter.
The tapered inner blade makes it easier to shave under the nose and under the chin. However, in conventional electric shavers with a large radius of curvature, even if the outer blade is flat, it can follow the inner blade, but as the radius of curvature becomes smaller, the outer blade must be curved significantly, and the inner blade It has the disadvantage that it becomes difficult to follow the hair, and there is a gap between the inner and outer blades, which causes the beard to become stretched. Furthermore, if the radius of curvature is simply made smaller, the area for cutting the beard becomes narrower with the semicircular inner blade, which has the disadvantage that the beard cannot be completely shaved without repeated shaving.

(Object of the Invention) The present invention has been proposed in view of the above points, and its purpose is to make it easy to shave even in hard-to-shave areas such as under the nose and under the chin.
By widening the area that can be shaved at one time, you can shave fewer times, and by improving the adhesion between the inner and outer blades, you can avoid pulling your beard, and even remove curly beards and beards. The purpose of the present invention is to provide an electric razor capable of shaving well even with beards.

(Disclosure of the Invention) In order to achieve the above object, the present invention comprises an outer cutter by curving an outer cutter plate and attaching it to an outer cutter mounting frame, and the radius of curvature of the upper end of the inner cutter blade is larger than the radius of curvature of the side surface. A reciprocating electric shaver blade having an inner blade that is small in size, characterized in that a side portion of the inner blade protrudes outward with respect to an extension line of the inner wall surface of the outer blade mounting frame. The gist of the invention is a reciprocating electric shaver blade.

Embodiments of the reciprocating electric shaver blade of the present invention will be described below with reference to the drawings.

FIG. 1 is an exploded perspective view showing the overall structure of a reciprocating electric shaver according to an embodiment of the present invention.
In the figure, the outer cutter 1 is locked to the outer cutter mounting frame 2, and the inner cutter 3 has a plurality of inner cutter blades 4 supported by inner cutter blade support ribs 3c, and the inner cutter 3 has a reciprocating motion provided on the main body 5. It is attached to the drive element 6 that performs the operation. A spring (not shown) is installed inside the driver 6 to press the inner cutter 3 against the outer cutter 1. The outer blade attachment frame 2 is attached to the main body 5 via the locking hook 7 of the main body 5.
will be installed on the 8 is a switch provided on the side of the main body 5. The inner cutter 3 has a tapered shape by making the radius of curvature of the top part 3a smaller than that of the side part 3b, and the circumference of the cutting edge is longer than that of the inner cutter 3, which is simply an arc shape with a small radius. The area to be cut is enlarged.

FIG. 2 is a sectional view showing the shapes of the outer cutter 1 in a free state before being attached to the outer cutter mounting frame 2, and the inner cutter blade 4 constituting the inner cutter 3. The outer cutter 1 has a flat shape and an inner cutter blade 4. The blade 4 is pre-formed to have an intermediate shape. At the top of the outer cutter 1 in this free state, the inner cutter 3
The difference in shape between the two is compared and shown by arranging them so that their vertices are in contact with each other. The distance between the outer cutter 1 in the free state and the cutting edge of the inner cutter blade 4 is g, and the distance from the apex of the outer cutter 1 to the side surface is Y, and the distance g is the highest point. The outer cutter 1 and the inner cutter 3 are overlapped so that the angle is (0,0). The shape of the outer cutter 1 is such that this gap g becomes larger toward the side surface, that is, as the value of Y becomes larger. In other words, from the radius of curvature of the inner cutter 3 at each corresponding part of the inner cutter 3 and the outer cutter 1,
The radius of curvature of the outer cutter 1 is increased. In other words, the top portion 1a of the outer cutter 1, which is formed with a certain radius of curvature, is formed larger than the corresponding radius of curvature of the inner cutter 3, and the side portion 1b of the outer cutter 1 is formed in a straight line or at the top. It is formed with a radius of curvature larger than 1a.

When the outer cutter 1 thus formed is attached to the outer cutter mounting frame 2 by engaging the outer cutter locking plate 1c of the outer cutter 1 with the locking hook 2a of the outer cutter mounting frame 2, the outer cutter 1 Compared to the flat outer cutter, the radius of curvature is smaller at the top portion 1a, and the radius of curvature at the side portion 1b is larger than that of the top portion 1a, resulting in a shape closer to the shape of the inner cutter 3.

Furthermore, to specifically explain the shape of the curved surface of this outer cutter 1 with reference to FIG. 3, (a) shows the flat outer cutter 1.
, and when it is formed in advance into an almost arch-like shape as shown in (B), and further attached to the outer cutter mounting frame 2, the shape of the side part of the outer cutter 1 becomes curved as shown in (C). becomes.

FIG. 4 shows the shape of the outer cutter 1 attached to the outer cutter mounting frame 2. This is done by aligning the inner cutter 3 and the outer cutter 1 at the apex as in FIG. Indicated by a broken line. This figure shows the inner cutter 3 at the top of the outer cutter 1.
No force is applied to the outer cutter 1 and the inner cutter 3 just by temporarily matching them. In the figure, the side surface 1b of the outer cutter 1 to which no external force is applied is located outside the extension line h of the inner wall 2b of the outer cutter mounting frame 2, and similarly from the inner cutter 3 across a gap e. It has a shape that projects outward. In addition, when the inner cutter 3 and the outer cutter 1 are attached from this state and a push-up force P is applied to the inner cutter 3 from below, the contact starts from the top part 3a, and the inner cutter 3 is attached to the outer cutter mounting frame 3. inner wall 2b of
The structure is such that it extends further outward than the extension line h.

FIG. 5 shows a state in which the inner cutter 3 is pressed against the outer cutter 1 mounted on the outer cutter mounting frame 2 by a push-up force P by a spring or the like, and the inner cutter 3 is in close contact with the outer cutter 1.

However, if the inner cutter 3 is made to touch the extension line h of the inner wall 2b of the outer cutter mounting frame 2, and if the inner cutter 3 is formed inside the shape shown in the figure, the present invention In the case of a tapered inner cutter 3 having a larger radius of curvature at the side surface 3b than at the top 3a, a gap easily occurs between the inner cutter 3 and the outer cutter 1 because the side surface 3b has a large inclination. This means that the blade 3 and the outer blade 1 cannot come into close contact with each other.

In other words, in the present invention, even if the shape of the cutting edge of the inner cutter blade 4 changes somewhat, the distance f between the inner wall 2b of the outer cutter mounting frame 2 and the extension line h is increased to compensate for this change. This ensures good adhesion.

In addition, the shape of the outer cutter 1 with respect to the shape of the inner cutter 3 is such that the gap g is zero at the apex and increases toward the side, because the inner cutter 3 and the outer cutter 1 are closely connected. Experiments have shown that if the inner cutter and outer cutter 1 are brought into contact in order from the top to the side as shown in Fig. 4, the push-up force P of the inner cutter 3 is smaller than when the inner cutter and outer cutter 1 are contacted from the side first. It has been confirmed by etc.

Of course, ideally, the inner cutter 3 and the outer cutter 1 should have the same shape, but when forming the outer cutter 1 or the inner cutter 3, the shape always changes. , In that state, outer cutter 1 and inner cutter 3
If the inner cutter 3 and the outer cutter 1 are attached, an inconvenient situation may arise in which the inner cutter 3 and the outer cutter 1 begin to come into close contact from the side surfaces first.

Therefore, in the present invention, the shapes of the inner cutter 3 and the outer cutter 1 are set so that even if the shapes of the inner cutter 3 and the outer cutter 1 are slightly changed during molding, they always come into contact from the top side. be.

FIG. 6 is an explanatory diagram showing the relationship between the two, with the distance from the apex of the outer cutter 1 to the side surface as the Y coordinate, and the gap e between the inner cutter 3 and the outer cutter 1 as the e coordinate. The state where the inner cutter 3 and the outer cutter 1 first come into contact is shown as A, the stage where the inner cutter 3 and the outer cutter 1 are coming into close contact is shown as B, and the state where the inner cutter 3 and the outer cutter 1 are in close contact is shown as C.

Figure 7 shows the distance from the apex of the outer cutter 1 to the side surface as the Y coordinate, and the slope θ of the tangent to the cutting edge of the inner cutter blade 4 as θ.
It is an explanatory diagram showing the relationship between the two in terms of coordinates, and in the present invention, the inclination θ of the tangent to the cutting edge of the inner blade 4 is
is set to continuously and monotonically increase like the curve A shown in FIG. This means that even if the shape of the cutting edge of the outer cutter 1 changes continuously, if the tangent line changes, for example, into the curves shown in B and C in Fig. 7, discontinuous parts as shown in parts A and A of those curves This is because, if there is an inflection point, a corresponding gap will be generated between the outer cutter 1 and the inner cutter 3.

In the present invention, the radius of curvature of the top portion 3a of the inner cutter 3 is made smaller than the radius of curvature of the side surface portion 3b, so that the outer cutter 1 and the skin 9 can be connected to each other as shown in the explanatory view of the usage state in FIG. Since the whiskers 10 enter the surface of the outer cutter 1 at an angle close to perpendicular to the boundary between the contacting portion and the non-contacting portion, the whiskers 10 are easily introduced into the cut hole 1d of the outer cutter 1 efficiently and more deeply. This is the inner blade 3, which is likely to be cut short because it penetrates.
This is because the beard 10 stands more perpendicularly to the skin 9 because the tip of the beard is thin.

Contrary to the configuration of the present invention described above, a case will be described in which the radius of curvature of the top portion 3a of the inner cutter 3 is made larger than the radius of curvature of the side surface portion 3b. In this case, the whiskers 10 enter the surface of the outer cutter 1 at a small angle, and the whiskers 10 often hit the outer cutter crosspiece between the blade holes 1d of the outer cutter 1. This will make it difficult to implement.

Further, in the present invention, the top portion 1a of the outer cutter 1
Since the radius of curvature of the outer cutter 1 is smaller than that of the side surface 1b, the contact pressure between the outer cutter 1 and the skin 9 is greater at the top 1a than when the radius of curvature of the top 1a is larger. It becomes smaller in part 1b. Therefore, in the side surface portion 1b, the cutter hole 1d of the outer cutter 1 can be made larger than in the conventional case. This is because the contact pressure is small, so the amount that the skin 9 penetrates into the blade hole 1d becomes smaller, and the amount that the skin 9 is scraped by the inner cutter 3 becomes smaller, and the blade hole 1d is made larger accordingly. This makes it easier to introduce the hair 10 into the blade hole 1d.

The size of this cutter hole 1d is explained in FIG. 9, in which A is a developed view showing the cutter hole 1d of the outer cutter 1, and B is an enlarged view of the main part of A. As shown in the figure, the cutter hole 1d of the outer cutter 1 is arranged so that the longer diameter L gradually increases from the top portion 1a, and the longer diameter L has a suitable length of 0.8 to 1.2 mm. This is determined by the strength of the outer cutter 1, and generally the upper limit is approximately 1.2
This is because the minimum diameter is about 0.8 mm or more to satisfy the introduction of the whiskers 10.

In this way, by forming the blade hole 1d large in the side surface portion 1b of the outer cutter 1, the beard 10 can be shaved efficiently and in a short time.

FIG. 10A shows the shape of the outer cutter 1' of another embodiment, and FIG. 10B is an enlarged view of the main part thereof. This is because the outer cutter 1' is pre-formed in a shape that protrudes outward at the side surface 1'b, and by forming it in this way, when the inner cutter is pushed up, it comes into closer contact with the outer cutter 1'. be able to.

Further, as an example of embodying the present invention, the cutting edge curve of the inner blade may be selected to have a substantially parabolic shape in which the curvature gradually changes, in addition to the substantially elliptical shape shown in West German Patent No. 932172.

FIG. 11 shows the shape of the inner blade 4 made into a parabola, where the apex is the origin of the X and Y coordinates, and the outer shape of the inner blade 4 is formed by an upwardly convex parabola. Since the slope of the tangent to this curve increases monotonically as shown in A shown in FIG. 7, it has the advantage that when the inner cutter and the outer cutter are attached, they tend to align together.

(Effects of the Invention) The present invention reduces the radius of curvature of the top of the inner blade of a reciprocating electric razor, making it easier to target beards even in hard-to-shave areas such as under the nose and under the chin. A reciprocating type that increases the size of the area that can be shaved, allowing you to shave fewer times, and improves the adhesion between the inner and outer blades, giving you a comfortable shave without pulling your beard. It has the effect of making an electric shaver possible.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view of an embodiment of the present invention, and FIG.
The figure is a cross-sectional view showing the shapes of the outer cutter 1 and the inner cutter 3 in a free state, and FIG. 3 is an explanatory diagram of forming and assembling the outer cutter 1.
Fig. 4 is an explanatory diagram comparing the shapes of the outer cutter 1 and the inner cutter 3, Fig. 5 is a sectional view of the outer cutter 1 and the inner cutter 3 installed, and Fig. 6 is an explanatory diagram comparing the shapes of the outer cutter 1 and the inner cutter 3. FIG. 7 is an explanatory diagram of the change in the gap e, FIG. 7 is an explanatory diagram of the slope θ of the tangent to the cutting edge of the inner cutter blade 4, FIG. 8 is an explanatory diagram of the usage state, and FIG.
Figure A is a developed view of the outer cutter 1, Figure 9B is an enlarged view of the main parts of Figure 10, and Figure 10A is a sectional view of another embodiment of the outer blade.
FIG. 10B is an enlarged view of the main part of A, and FIG. 11 is an explanatory diagram of the shape of the inner blade 4. 1, 1'...Outer blade, 1a...Top part, 1b, 1'b...
Side part, outer blade locking plates 1c, 1d...blade hole, 2...outer blade mounting frame, 2a...locking hook, 2b...inner wall, 3...
Inner blade, 3a... Top part, 3b... Side part, 3c... Inner blade support rib, 4... Inner blade blade, 5... Main body, 6... Drive element, 7... Locking hook, 8... Switch, 9... Skin, 10...beard, e...gap, f...distance,
g...distance, h...extension line, L...major axis, P...pushing force, θ...tangential slope.

Claims (1)

[Scope of Claims] 1. An outer cutter is constructed by curving an outer cutter plate and attaching it to an outer cutter mounting frame, and has an inner cutter blade in which the radius of curvature of the upper end of the inner cutter blade is smaller than the radius of curvature of the side surface. A reciprocating electric shaver blade, characterized in that a side surface of the inner blade protrudes outward from an extension of the inner wall surface of the outer blade mounting frame. 2. The reciprocating electric shaver blade according to claim 1, characterized in that a portion of the outer cutter corresponding to the protruding portion of the inner cutter blade protrudes outward. 3. The radius of curvature of the outer cutter plate is larger than the radius of curvature of the inner cutter blade when the outer cutter plate is attached to the outer cutter mounting frame and the tops of both the outer cutter plate and the inner cutter blade are aligned. A reciprocating electric shaver blade according to claim 1, characterized in that: 4. The blade of a reciprocating electric shaver according to claim 1, wherein the blade hole in the side surface of the outer cutter plate is longer than the blade hole in the top part.