JPS5850751B2 - Dendo razor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, an inner cutter that rotates in sliding contact with the inner surface of a dome-shaped outer cutter is fitted into an inner cutter insertion hole of an inner cutter holder so as to be movable up and down, and the base of this inner cutter is inserted into the inner cutter of the above-mentioned holder. The present invention relates to an electric shaver that is elastically supported by the free end of a support spring fixed to the electric shaver, and is adapted to reduce friction between the inner cutter and the outer inner surface of the inner cutter insertion hole.

Generally, this type of electric shaver requires the inner cutter to slide into contact with the inner surface of the outer cutter for rotational movement.For this purpose, the inner cutter is biased with a predetermined spring force and is slidably pressed against the outer cutter. There is.

Conventionally, this spring force is used to compensate for the friction loss between the inner cutter and the outer inner surface of the inner cutter insertion hole, which is caused by the centrifugal force caused by the rotation of the inner cutter. It is calculated as the addition of

This friction loss puts an unnecessary load on the motor, which has various drawbacks, such as accelerating battery discharge, especially in battery-powered razors.

The present invention was developed in view of these points, and is designed so that the center of gravity of the inner cutter 5 that rotates while slidingly contacting the inner surface of the dome-shaped outer cutter 7 is located within the inner cutter insertion hole 4a of the inner cutter holder 4. Insert the inner cutter 5 into the inner cutter insertion hole 4a so that it can move up and down,
A spring force for pressing the inner cutter 5 against the outer cutter 7 and a spring force toward the center of the inner cutter holder 4 are applied to the free end 6a of the support spring 6 whose base end is fixed to the inner cutter holder 4. By connecting this free end portion 6a to the inner cutter 5 at a position below the center of gravity of the inner cutter 5, the inner cutter 5 is provided with an inner cutter 5 to the extent that the inner cutter 5 and the outer inner surface of the inner cutter insertion hole do not separate from each other. The centripetal force of the shaver is energized to subtract and reduce the frictional force generated by centrifugal force due to rotation, thereby reducing the load on the motor and providing an electric shaver that consumes less power than conventional shavers. It is something.

Furthermore, the present invention simplifies the structure and improves the followability of vertical movement by exerting the original inner blade pushing spring force and the spring force in the center direction with one support spring. This is what I did.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a partially cutaway sectional view of essential parts showing an example of an electric shaver according to the present invention, in which 1 is a case, 2 is a motor, 3 is a rotating shaft of the motor, and 4 is a rotating shaft 3. The attached inner blade holder, 4a is an inner blade insertion hole, 4b is a square hole for supporting a spring, 5 is an inner blade, 5a is a through hole drilled in the center of the base of the inner blade 5,
6 is a support spring fixed to the square hole 4b, 6a is a free end of the support spring, 7 is a dome-shaped outer cutter with the top at the center, and 8 is an outer cutter holder.

The inner cutter 5 is fitted into the inner cutter insertion hole 4a of the inner cutter holder 4 so as to be vertically movable, and the free end 6a of the support spring 6 fixed to the holder 4 is inserted into the through hole 5a of the inner cutter 5. The inner cutter 5 is supported elastically by the support spring 6, and is slidably held on the inner surface of the outer cutter 7 under the bias of the spring force of the support spring 6.

FIG. 2 is a sectional view taken along the line I--II in FIG. 1, and the same parts as in FIG. 1 are given the same numbers and detailed explanation thereof will be omitted.

Now, in FIG. 2, the spring supporting square hole 4b is set inside the through hole 5a bored in the center of the base of the inner cutter 5, as shown by a chain line extending from this diagonal line.

The inner cutter 5 is inserted into the inner cutter insertion hole 4a of the inner cutter holder 4, and the base of the inner cutter 4 is supported by the free end 6a of the support spring 6 fixed to the square hole 4b. 5 is biased by an upward spring force and a centripetal spring force, which presses the inner cutter 5 against the inner surface of the outer cutter 7 and reduces centrifugal force due to rotation.

Next, its operation will be explained with reference to FIG.

FIG. 3 is an enlarged cross-sectional view illustrating the function of the main parts in FIG.
In the figure, G is the weight of the inner cutter 5 placed in the insertion hole 4a of the inner cutter holder 4, F is the centrifugal force acting on the center of gravity G, F' is the centripetal force exerted by the support spring 6, and C is the inner cutter insertion force. The vertical distance d from the top surface of the hole 4a to the center of gravity G is the vertical distance from the top surface of the insertion hole 4a to the through hole 5a formed in the inner blade 5 inserted into the insertion hole 4a.

First, in the non-driven state, the inner cutter 5 is pressed against the inner inner surface side of the inner cutter insertion hole 4a by the centripetal force F' by the support spring 6.

Next, when the inner cutter holder 4 rotates and enters the driving state, a centrifugal force F acts on the inner cutter 5. This centrifugal force F causes the center of gravity G of the inner cutter 5 to be located within the inner cutter insertion hole 4a. Since the inner blade 5
is moved toward the outer inner surface of the inner blade insertion hole 4a.

On the other hand, the inner cutter 5 has a centripetal force F' in the opposite direction to the centrifugal force F.
is working.

Therefore, next, the influence of the frictional force between the inner cutter 5 and the outer inner surface of the inner cutter insertion hole 4a due to the centrifugal force F in this driving state will be examined.

First, considering a state in which there is no centripetal force F', in this state, the centrifugal force F acts as a pressing force toward the outer inner surface of the inner blade insertion hole 4a with almost the same amount. Therefore, there is a μ between the two.

- A frictional force of F (μ is the coefficient of static friction) will be generated.

However, in the present invention, since the centripetal force F' in the opposite direction to the centrifugal force F is appropriately applied, the frictional force between the inner cutter 5 and the inner cutter insertion hole 4a is μ0·(F-F'). , frictional resistance can be reduced.

Next, let us consider the centripetal force F' at the limit point where the two do not separate.

'The size of F' at this limit point is the inner blade insertion hole 4a.
It is obtained from the equation of moment balance centered on point B at the upper end of the outer surface of .

That is, F-c=F'・d,", F'=F-c/d... (
1).

In this case, since the outer cutter 7 is formed in a dome shape with the top at the center, the inner cutter push-up blade Ft of the support spring 6 is connected to the outer cutter 7 and the inner cutter 5 as shown in FIG. Outer blade 7 between
A component force Ft' toward the center of is generated.
), this center-direction component force Ft' is ignored for the time being.

Therefore, to explain this in consideration of the above-mentioned center component force Ft', the inner cutter 5 has centripetal force F' at the lower part and center-direction component force Ft' at the upper part acting in the same direction as this centripetal force y, both of which are caused by centrifugal force F Therefore, these F' and Ft' work together to reliably reduce the frictional force between the inner cutter 5 and the outer inner surface of the inner cutter insertion hole 4a.

As described above, according to the present invention, the inner cutter 5 is arranged such that the center of gravity of the inner cutter 5 that rotates while slidingly contacting the inner surface of the dome-shaped outer cutter 7 is located within the inner cutter insertion hole 4a of the inner cutter holder 4. is inserted into the inner cutter insertion hole 4a so as to be movable up and down, and a spring that presses the inner cutter 5 against the outer cutter 7 is attached to the free end 6a of the support spring 6 whose base end is fixed to the inner cutter holder 4. By applying a force and a spring force toward the center of the inner cutter holder 4, and connecting the free end 6a at a position below the center of gravity of the inner cutter 5,
The centrifugal force F generated on the inner cutter 5 during high-speed rotation is reduced by utilizing the fact that the centripetal force F' applied in advance to the support spring 6 of the inner cutter 5 acts in the opposite direction to the centrifugal force F. let me,
It is possible to reduce the frictional force between the inner cutter 5 and the inner cutter insertion hole 4a, and to actively make it possible for the pushing-up force Ft of the support spring 6 to generate a center-direction component force Ft' due to the dome shape of the outer cutter 7. In combination with the centripetal force F', it is possible to reliably reduce the frictional force, reduce the load on the motor, and provide an electric shaver that consumes less power than conventional ones. Smooth vertical movement,
Sharpness can be improved.

Furthermore, according to the present invention, the structure for reducing the frictional force can be obtained with a simple structure in which the support spring 6 also serves as the structure, and there is no need to add unnecessary parts to the inner cutter part that rotates at high speed, and the structure is further improved. An electric shaver with low power consumption can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway sectional view of essential parts showing an embodiment of the electric shaver according to the present invention, and FIG.
A line sectional view and FIG. 3 are enlarged sectional views illustrating the functions of the main parts. 4...Inner blade holder, 4a...Holder insertion hole, 5...Inner blade, 5a...Through hole drilled in the inner blade, 5b ...Innermost end of inner cutter slidingly in contact with outer cutter, 6... Support spring, 6a... Free end of support spring, 7... Outer end blade.

Claims (1)

[Claims] 1. The inner cutter 5 can be moved up and down into the inner cutter insertion hole 4a of the inner cutter holder 4 so that the center of gravity of the inner cutter 5, which rotates in sliding contact with the inner surface of the dome-shaped outer cutter 7, is located within the inner cutter insertion hole 4a of the inner cutter holder 4. At the same time, a spring force for pressing the inner cutter 5 against the outer cutter 7 and a spring force toward the center of the inner cutter holder 4 are applied to the free end 6a of the support spring 6 whose base end is fixed to the inner cutter holder 4. The electric shaver is characterized in that the free end portion 6a is connected to the inner cutter at a position below the center of gravity of the inner cutter 5.