JPS6124220Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drive mechanism for reciprocating small electric appliances, such as reciprocating electric shavers, electric hair clippers, and electric pine surgeons.

For example, in the case of a reciprocating electric shaver, the inner blade is attached to a drive body having flexible legs as the inner blade drive means, and the drive body is vibrated in the left-right direction by the rotational movement of an eccentric cam driven by a motor. A method has been proposed in which the inner cutter is reciprocated along the inner surface of the outer cutter.

FIG. 1 is an exploded perspective view of a well-known electric shaver using this type of drive body.
At the lower end of each leg 3, a mounting portion 4 for attaching to the frame is formed. This leg 3 is
It is made of a flexible material and is extremely thin and long enough to allow sufficient vibration of the substrate 2 in the left-right direction.

A base 5 having an inner hole is formed on the upper center surface of the substrate 2, and an inner cutter 7 is attached to the tip of a driving rod 6 erected on the base 5. In addition, an eccentric cam 9 attached to the output shaft of the motor 8 is provided in the inner hole of the base 5.
Upper pin 10 is inserted. 11 is an outer cutter, 12 is an inner cutter holder, 13 is a spring for elastic contact of the inner cutter, and 14 is a hair stopper plate.

Now, when the pin 10 inserted into the inner hole of the base 5 rotates due to the drive of the motor 8, the base plate 2 of the driver 1 vibrates in the left-right direction, and the inner cutter 12 reciprocates along the inner surface of the outer cutter 11. do. At this time, each leg 3 vibrates about the attachment part at the lower end as a fulcrum and easily shifts from a transient state to a steady state and maintains the steady state, thus continuously generating resonance sound. In this case, as mentioned above, the legs 3 are formed to be very thin (for example, 30 to 50 μm) and long so as not to be loaded with the vibrations of the board 2, so the resonance sound is extremely loud, and the legs 3 are This acts as a diaphragm similar to a speaker, causing discomfort to the user.

Further, as shown in FIG. 2, in order to reduce air resistance and ensure sufficient flexibility of the leg pieces, it is already possible to form a vertically long hole 17 in the leg piece 16 of the drive body 15. However, since this elongated hole was formed exactly in the center of the leg, and the long side of this elongated hole was parallel to the edge of the leg, it would still be in a steady state and produce a large resonance sound. There are some flaws that can easily occur.

Therefore, the present invention was devised for the purpose of preventing the generation of resonance noise due to the legs of this type of driving body, and by forming holes of a certain shape in the legs, the legs can be kept in a steady state. This prevents the state from being maintained and prevents the occurrence of large resonance noise.

Hereinafter, embodiments will be described with reference to the drawings, taking an electric shaver as an example.

3 and 4 are a front view and a side view of the driving body, in which the main driving body 18 is made of flexible synthetic resin such as polyacetal resin or nylon resin, and a thick substrate 19 is shown. It consists of a thin, long rectangular leg portion 20 extending downward from both sides of the board, and a thick mounting portion 21 formed at the lower end of the leg. Further, a substrate 22 is formed on the upper center surface of the substrate 19, and a driving rod 23 is erected on the base 22.

Each leg portion 20 is formed with an isosceles triangular hole 24 with its base facing upward. This triangular hole 2
4 is formed symmetrically with respect to the neutral axis N.Ay of the leg portion 20 in the Y direction so as not to cause lateral wobbling, but it is asymmetrical with respect to the neutral axis N.Ax of the X direction, and its centroid G is above the neutral axis N・Ax. Therefore, each hypotenuse of the triangular hole 24 is non-parallel to the edge of the leg 20, and the distances ₁ , ₂ , ₃ from the edge to each point on the hypotenuse vary. Note that each corner of the triangular hole 24 is rounded to prevent cracks.

Now, the motor 8 rotates at about 5500 to 5800 rpm, and the drive of this motor 8 causes the substrate to
When the leg 9 reciprocates in the left-right direction, each leg 20 vibrates about the mounting part as a fulcrum, but the leg 2
Since the triangular hole 24 is formed in 0, it is not possible to shift to a steady state, and even if the steady state is reached, it immediately returns to the transient state. Therefore, the main leg portion 20 does not generate a water-like resonance sound.

However, since the leg portion 20 vibrates around the attachment portion 21 at the lower end as a fulcrum, the amplitude of the leg portion 20 increases as it moves upward (that is, as it moves away from the attachment portion 21), and reaches its maximum at the boundary with the substrate 19. Therefore, the air resistance against the vibration of the legs is more severe as it moves upward, resulting in a larger load. However, in this embodiment, the triangular hole has its base facing upward, and the centroid G
Since it is formed to be offset above the neutral axis N.Ax, the opening area becomes larger as it goes upward, and therefore air resistance is effectively reduced to a large extent in the upward direction where the amplitude is large.

FIGS. 5 and 6 show other embodiments of the leg 20.
The holes formed in the holes 24' and 24'' are rectangular in shape, and in _{the one} in FIG. Legs 2
0 and the lower edge 33 of _the rectangular hole 24', and are set at the same position in terms of width.

In FIG. 6, the rectangular hole 24'' is divided into two parts, and the upper hole is set larger than the lower hole.By increasing the hole area upward, the resonance point can be shifted.

As explained above, according to the present invention, since the vibration of the legs can be prevented from reaching a steady state, unpleasant resonance noise is not generated, and when using an electric razor, a comfortable shave can be performed. , the vibration frequency range used by small electrical equipment using this type of drive mechanism is approximately 5000 to 6000Hz,
According to the present invention, the resonance point in this range can be easily shifted and set.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of a conventional electric shaver, FIG. 2 is a side view of another conventional electric shaver, FIG. 3 is a front view of the driver of the present invention, and FIG. 4 is a side view of the same.
5 and 6 are side views of other embodiments of the driving body of the present invention. 18...driver, 19...substrate, 20...leg, 24...triangular hole.

Claims (1)

[Scope of utility model registration request] A drive mechanism for a small electrical device, comprising: a substrate having rectangular flexible legs formed at both ends thereof, each of which has a hole formed therein, and the hole has a shape such that the length from the edge of the leg to the periphery of the hole varies.