JPS6351036B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an inner cutter of a rotary electric shaver.

[Background technology]

The inner cutter of a rotary electric shaver generally has a tip end of a push-up spring engaged with an opening at the base end of the inner cutter blade to bring the inner cutter blade into contact with the outer cutter. However, in the prior art, for example, Utility Model Publication No. 43-23551, the opening was small, so it was difficult to engage the tip of the push-up spring, and as a result, assembly was troublesome.

In contrast, a conventional example in which assembly is facilitated by making the opening larger is shown in FIGS. 9 and 10. That is, in the figure, 50 is an outer cutter frame, 51 is an outer cutter, 52 is an inner cutter base, 53 is a push-up spring, 54 is an inner cutter blade, and the push-up spring 5
3, the inner cutter blade 54 is pushed up and inscribed in the outer cutter 51, and the hair that has entered the cutter hole of the outer cutter 51 due to the rotation of the inner cutter base 52 is cut.

In this type of rotary electric shaver, openings 55a to 5 are provided at the lower end of the inner blade 54 to engage the push-up spring 53 with the inner blade 54.
5c and a notched opening 55
There were some that had retaining protrusions 56 and 57 formed on the side edges of a and 55c (for example, Utility Model No. 58-190475).
issue). However, in this push-up method, during actual use, a centrifugal force in the radially outward direction N is applied to the push-up spring 53 due to rotation of the inner cutter base 52 about the central axis OO. The push-up spring 53 is fixed to the inner cutter base 52 by heat sealing or the like, but because gaps are likely to occur and the spring itself is elastically deformed, the tip moves slightly outward in the radial direction. Since the inner cutter blade 54 is supported by the slit 58 of the inner cutter base 52 and hardly moves radially outward, the engagement range δ with the push-up spring 53 at the retaining protrusion 57 is small and approaches 0, resulting in When cutting, the push-up spring 53 comes off due to vibrations in the axial direction (vertical direction in the figure) applied to the inner blade 54.
As a result, a predetermined pressure force cannot be obtained, resulting in poor cutting quality.

In addition, since the distance A between the upper edge, which is the push-up point at the opening 55a of the inner blade 54, and the retaining protrusion 56 is relatively large, the inner blade 54 is
When vertical bouncing occurs, the push-up spring 53 vibrates within this distance A, and since it takes a long time to converge, the inner blade 54
However, the sliding contact state of the outer cutter 51 is unstable, resulting in poor cutting quality.

FIG. 11 also shows the opening 5 of the inner blade 54'.
This shows another push-up method using a hole as the push-up spring 53', but in this case, while the push-up spring 53' is difficult to come off,
In order to make it easier to insert the push-up spring 53', the vertical width B of the hole is increased, so that the spring 53' during vibration
The disadvantage is that the convergence time is long and the sharpness is poor.

[Purpose of the invention]

The purpose of this invention is to enable the tip of the push-up spring to easily engage with the opening of the inner cutter blade, to prevent the push-up spring from coming off during shaving, and to prevent the push-up spring from constricting during vibration. To provide an inner blade of a rotary electric shaver that can save time.

[Disclosure of the invention]

The inner blade of the rotary electric shaver of the present invention includes an inner blade base passing through a slit for inserting the inner blade;
A pressing spring whose base end is fixed to the lower surface of the inner cutter base and whose tip faces the lower end of the slit, and an opening that is inserted through the slit and engages the tip of the pressing spring are formed. A retaining protrusion is protruded on the side edge of the opening corresponding to the radially outward side of the inner cutter base, and the distance between the retaining protrusion and the pushed-up position of the opening is set so that the distance between the outer cutter and the above-mentioned an inner cutter blade having a distance smaller than the distance between the inner cutter bases plus the thickness of the push-up spring; This distance is smaller than the distance between the opposite side edge.

According to the configuration of the present invention, the width of the tip of the push-up spring is made smaller than the distance between the retaining protrusion of the opening and the side edge opposite to the retaining protrusion, so that the push-up spring can be easily removed from the opening. can be engaged with. Further, since the retaining projection is provided on the side corresponding to the radially outward side of the opening, it is difficult to come off due to the vibration of the push-up spring, and as a result of experiments, the convergence time can be significantly shortened due to the above-mentioned dimensional relationship.

A blade portion of a rotary electric shaver to which a first embodiment of the present invention is applied will be described with reference to FIGS. 1 to 7. That is, 1 is an outer blade having a cutting hole, 2
is the outer blade frame, 3 is the comb, 4 is the cover, 5 is the inner blade base, 6 is the slit for inserting the inner blade,
7 and 8 are inner cutter blades, 9 and 10 are push-up springs, and the push-up springs 9 and 10 have their base ends fixed to the lower surface of the inner cutter base 5 by heat-sealing parts 11 as shown in FIG. There is.

The inner blade 7 has an opening 12 cut out at its lower end for a push-up spring, and the inner blade 8 has an opening 1 formed in the lower end.
3 holes are formed. Further, a retaining protrusion 14 is integrally formed on the side edge of the openings 12 and 13 on the side corresponding to the radially outward N of the center of rotation. in this case,
As shown in FIG. 5, the width _B1 of the tip of the push-up spring 9 inserted into the opening 12 is as follows:
The tip of the retaining protrusion 14 and the retaining protrusion 14
The push-up position 12 of the upper edge of the opening 12 is smaller than the distance between the side edge of the opening 12 facing the
In a, it is set to engage with the retaining protrusion 14 by a dimension _A1 . Furthermore, the distance G between the push-up positions 12a and 13a of the openings 12 and 13 and the retaining protrusion 14 is added to the distance H between the outer cutter 1 and the inner cutter base 5 and the thickness t of the push-up springs 9 and 10. It is smaller than that.

Even if the push-up springs 9 and 10 move radially outward N by ΔR due to the centrifugal force when the inner cutter base 5 rotates, for example, if they reach the imaginary line, they will further engage with the retaining protrusion 14, and the amount of engagement will change. Since A ₂ > A ₁ , it becomes more difficult to come off. Further, during shaving, the push-up springs 9, 10 are pushed up to the opening 1 due to vibrations in the direction parallel to the axial direction applied to the inner blades 9, 10.
It vibrates within 2,13. This is because when the deflection of the outer cutter 1 is maximized at time 0, the push-up spring 9 is displaced to follow that displacement, and the push-up spring 9 is displaced at the next instant at the push-up position 12a.
It separates from the inner cutter blade 7, collides with the retaining protrusion 14 of the inner cutter blade 7, and gradually converges to a stationary state. The vibration convergence curve is shown in FIG. That is, the horizontal axis is time, and the vertical axis is the openings 12, 1 of the push-up springs 9, 10.
3, where P ₁ is the deflection amount at the time of maximum deformation of the outer blade, P ₂ is the deflection amount of the push-up springs 9 and 10 in a stationary state, and T ₁ and T ₂ are the amplitudes above the opening of the conventional example. The positions of the edge and the retaining protrusion, T ₃ and T ₄ are the push-up position 12a of the opening 12 and the position of the retaining protrusion 14 in this embodiment, and Q ₁ is the convergence curve of the push-up spring of the conventional example, Q ₂ is a convergence curve of the push-up spring 9 of this embodiment. As is clear from this figure, the convergence times τ ₁ and τ ₂ of the push-up springs are shorter in the embodiment than in the conventional example, that is, τ ₁ <τ ₂ .

Next, the convergence time τ of the push-up spring was measured with respect to the distance G between the push-up point and the retaining protrusion. The experimental conditions were a push-up spring constant of 5 gr/mm, a push-up spring thickness of 0.125 mm, a spring width of 0.7 mm, and a maximum blade deflection of 1.1 mm, and the results shown in Figure 7 were obtained. The horizontal axis is the distance between the push-up point 12a and the retaining protrusion 14, which is expressed based on the distance H between the outer cutter 1 and the inner cutter base 5. As is clear from this result, there is an inflection point near the distance X, which is the sum of the distance H and the thickness t of the push-up spring 9, and it can be seen that the convergence time is significantly shortened below this point. That is, this distance
Below this, the sharpness will last longer.

With this configuration, the inner blades 7, 8
The inner cutter blades 7 and 8 are more effectively prevented from coming off without impairing the assemblability of the inner blades 7 and 8, and the cutting quality is improved.

The inner blade 8 shown in FIG. 4 has an opening 13 formed therein, so that even if the push-up spring 10 should come off from the retaining projection 14, it will not come off from the inner blade 8.

A second embodiment of the invention is shown in FIG. That is, the dimension G ₁ corresponding to the dimension G of one of the openings 12 is made larger than the interval H plus the thickness t of the push-up spring 9, but the dimension G 1 of the other opening 1
Since the second protrusion 14 satisfies the above conditions, the first protrusion 14
This embodiment has the following effects.

〔Effect of the invention〕

According to this invention, the push-up spring can be easily engaged with the opening of the inner cutter blade, the push-up spring is difficult to come off from the retaining protrusion, and the cutting quality is maintained well during shaving. .

[Brief explanation of drawings]

Fig. 1 is a half-sectional side view of the blade of a rotary electric shaver to which the first embodiment of the present invention is applied, Fig. 2 is a bottom view of the inner cutter, and Figs. 3 and 4 are the inner cutter blade. Fig. 5 is a partial enlarged view of Fig. 3, Fig. 6 is a convergence curve diagram of the push-up spring during shaving, and Fig. 7 is a convergence time curve with respect to the distance G between the push-up position and the retaining protrusion. Figure 8 is the second
9 is a front view of the inner cutter blade of the embodiment, FIG. 9 is a half-sectional side view of the blade portion of the conventional example, FIG. 10 is a front view of the inner cutter blade, and FIG. 11 is a front view of another embodiment. be. 1... Outer blade, 5... Inner cutter base, 6... Inner cutter blade insertion slit, 7, 8... Inner cutter blade,
9, 10... Push-up spring, 11... Heat seal portion, 12, 13... Opening, 12a... Push-up position, 14... Retaining protrusion, B ₁ ... Width of tip of push-up spring, B ₂ ... Distance between the tip of the retaining protrusion and the side edge opposite the retaining protrusion, H... Distance between the outer cutter and the inner cutter base, G... Between the retaining protrusion and the push-up position distance.

Claims (1)

[Claims] 1. An inner blade base that passes through the slit for inserting the inner blade, a push-up spring whose base end is fixed to the lower surface of the inner blade base and whose tip faces the lower end of the slit, and which is inserted into the slit. and an opening that engages the tip of the push-up spring, and a retaining protrusion protrudes from a side edge of the opening corresponding to the radially outward side of the inner cutter base, and the retaining protrusion and an inner cutter blade having a distance between the push-up position of the opening and the push-up position smaller than the distance between the outer cutter and the inner cutter base plus the thickness of the push-up spring; An inner blade of a rotary electric shaver, wherein the width of the tip is smaller than the distance between the retaining protrusion of the opening and the side edge opposite to the retaining protrusion.