JPS607657Y2 - electric razor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric shaver that is configured to notify when the amount of remaining electricity in a battery that supplies power to a razor blade drive motor has decreased to a predetermined value.

With conventional electric razors, when the razor blade drive motor stopped rotating during shaving, the remaining electricity in the battery became zero, so the user had to stop shaving midway through the process. Ta.

Therefore, it is desirable to notify when the amount of remaining electricity in the battery that supplies power to the razor blade drive motor has decreased to a predetermined value, for example, an amount corresponding to one shave.

Further, it is desired that the notification be easily recognized by the shaver.

The present invention has been devised in view of these points, and one embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the electric circuit of an electric shaver.

B is a nickel-cadmium battery, which is charged from a commercial power source via a charging circuit 1.

The charging circuit 1 consists of a step-down transformer T1, a full-wave rectifier circuit RC, and a current-limiting resistor R1, and both ends of the primary coil of the step-down transformer T are respectively connected to plug blades 2, which are connected to a razor case as shown in FIG. It is attached within the case so as to protrude from 3.

Thus, battery B is connected to a motor M that drives the razor blade via an operating switch S, and batteries B are connected to both ends of the motor.
A switch circuit 4 is provided which detects when the remaining amount of electricity in the hair has decreased to a predetermined value, for example, the amount of electricity required for one shave, and makes the switch transistor Q1 conductive.

The switch circuit includes the base of the switch transistor Q□.
Detection transistor Q2 whose collector and emitter are connected to the emitter, and a resistor R that constitutes its base bias circuit.
A negative characteristic resistance element n is connected in series to the resistor R3 to compensate for variations in battery voltage depending on the ambient temperature.

Next, 5 is an oscillation circuit, including PNP transistors, NP
N transistor Q1, resistors R6, R7 and capacitor C
The emitter and collector of the PNP transistors are connected to both ends of the motor M via a lamp P as a notification element and a switch transistor Q, and the collector and emitter of the NPN transistor Q is connected to P via the lamp P.
NP) is connected between the base and collector of transistor Q3, and is connected between the collector of PNP transistor Q3 and the NPN) transistor Q.

A feedback circuit consisting of a resistor R7 and a capacitor C is inserted between the base of the resistor R7 and the base of the resistor R7.

The lamp P is located at the back of the window 6 of the razor case 3, as shown in FIG.

That is, a transparent body 7 is attached to the window 6 of the razor case 3, and a lamp P is attached between opposing pieces 8, 8 provided on the transparent body.

Then, when the operating switch S is closed, the battery B is discharged according to the discharge characteristic X shown in FIG.

Assuming that while the motor M is operating, the battery voltage drops to a voltage V1 that is equivalent to the amount of remaining electricity equivalent to two shaves, at this point the detection transistor Q2 is turned off and the switch transistor Q1 is turned on.

Therefore, the oscillation circuit 5 is supplied with power from now on, and the resistance R
The lamp P blinks according to a time constant determined by 7 and the capacitor C.

This flashing cycle is determined so that the shaver can visually recognize it, so the shaver can notice that the amount of remaining electricity in the battery is low.

Note that the point in time when the remaining amount of electricity in the battery has decreased is defined as shaving 1.
If the voltage V2 is reached at the time when the voltage V2 reaches the amount of remaining electricity corresponding to the battery charge, the voltage V2 in this case is easy to detect because it is greatly different from the voltage in the region W which shows a slow change in the discharge characteristic X.

Characteristic Y in FIG. 3 indicates the applied voltage characteristic of the oscillation circuit 5.

As described above, the present invention includes a battery that supplies power to a motor that drives a razor blade, a switch circuit that includes a switch transistor that becomes conductive when the amount of remaining electricity in the battery decreases to a predetermined value, and an oscillation that occurs when the transistor conducts. The switch circuit includes a detection transistor that controls conduction/non-conduction of the switch transistor, and a bias circuit at the base of the detection transistor. By having a resistance voltage divider circuit and inserting a negative characteristic resistance element in series with one of the resistors constituting the voltage divider circuit to compensate for fluctuations in the voltage of the battery depending on the ambient temperature, Due to the function of the characteristic resistance element, it is not only possible to always accurately detect the battery voltage even if the ambient temperature fluctuates, but also the values of the resistors R2 to R5 connected to the battery and the negative characteristic resistance element are determined according to the voltage characteristics of the battery. Therefore, the time point at which the notification element is detected can be made more accurate.

Also, since the notification element blinks due to the action of the oscillation circuit,
Compared to continuous lighting, battery consumption is lower and the time from when the flashing starts until the motor stops working can be extended, which has the effect of creating more time until the next charge.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is an electric circuit diagram of an electric shaver, FIG. is a diagram of the discharge characteristics of the battery. M...Motor, B...Battery, Q2...
...Transistor, R2, R3, R4, R5...
...Resistance, n...Negative characteristic resistance element, 4...
...Switch circuit, 5...Oscillation circuit, P...
...Notification element (lamp).

Claims (1)

[Scope of utility model registration request] A switch circuit including a battery that supplies power to a motor that drives a razor blade, a switch transistor that conducts when the amount of remaining electricity in the battery decreases to a predetermined value, an oscillation circuit that oscillates when the transistor conducts, and the oscillation circuit that oscillates when the transistor conducts. a notification element operated by the output of the circuit, the switch circuit having a detection transistor that controls conduction/non-conduction of the switch transistor, and a resistive voltage divider circuit forming a base bias circuit of the detection transistor, An electric shaver characterized in that a negative characteristic resistance element is inserted in series with one of the resistors constituting the voltage dividing circuit to compensate for fluctuations in the voltage of the battery depending on the ambient temperature.