JPS62173Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a solenoid control circuit that adjusts the electric power for exciting an alternating current directly driven solenoid and varies the striking force of a driver integrated with the movable core of the solenoid.

Generally, in electric impact tools, a rod-shaped or blade-shaped driver integrated with the movable core of the impact solenoid is reciprocated by energizing or demagnetizing the impact solenoid, and the nails or staples connected in parallel are continuously driven into the material to be driven. I try to type into it.

Two methods have been proposed for exciting the impact solenoid: capacitor drive and alternating current direct drive. AC direct drive electric impact tools are
Extremely lightweight compared to capacitor driven type
In addition, it can be made compact, that is, it has excellent operational performance, only half-wave energization control is required for the two controls of charging and discharging the driving capacitor, and the time constant of the driving capacitor is It has recently become widely used because it has characteristics such as excellent rapid firing performance due to no restrictions.
There is a drawback in that it is difficult to construct a circuit that causes the percussion solenoid to be excited and also makes the intensity of this excitation variable.

An object of the present invention is to provide a solenoid control circuit which causes one solenoid to be energized during one operation of a manual trigger switch, and which can vary the intensity of the solenoid's excitation. To achieve this objective, the present invention consists of a solenoid that is connected to both terminals of an AC power source and is supplied with an alternating current through a bidirectional three-terminal thyristor in series, and a solenoid that is connected to both terminals of an alternating current power supply and that is erected with a variable phase delay in the alternating current. one unidirectional three-terminal thyristor having a rectified output that falls; and a unidirectional three-terminal thyristor that generates a rectified output that falls with a certain phase difference L with respect to the fall of the rectified output, and the above-mentioned phase difference L.
A trigger pulse generation circuit that generates a trigger pulse having a pulse width L corresponding to the phase of the rectified output of one unidirectional three-terminal thyristor, and a manual trigger switch having a common terminal, a normally open terminal, and a normally closed terminal. One terminal of a double excitation prevention capacitor is connected to the common terminal of the double excitation prevention capacitor, the other terminal of this double excitation prevention capacitor is connected to the anode terminal of a discharge prevention diode, and the cathode terminal of this discharge prevention diode is connected to one power supply terminal. Turn-on is controlled by a trigger circuit in which the normally closed terminal of the trigger switch and the anode terminal of the discharge prevention diode are connected, and a trigger pulse from the trigger pulse generation circuit, thereby turning on the bidirectional three-terminal thyristor. The cathode side of the other unidirectional three-terminal thyristor is connected to the normally open terminal of the manual trigger switch, and the common terminal of the manual trigger switch and the normally open terminal are connected to each other. When connected, the other unidirectional three-terminal thyristor is turned on within the pulse width L of the trigger pulse to charge the double excitation prevention capacitor and at the same time the two-way three-terminal thyristor is turned on, thereby The gist is that the solenoid is excited.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. 1 to 3. FIG. 1 shows a solenoid control circuit 1 according to the present invention, and FIGS. 2 and 3 show output voltage waveforms of each thyristor and double excitation prevention capacitor. In FIG. 1, a striking solenoid 2 and a bidirectional three-terminal thyristor 3 are connected in series, and one end 2 of the striking solenoid 2 is not connected to the bidirectional three-terminal thyristor 3.
a is connected to one power supply terminal 4 of the 100V AC power supply, and the first terminal 3a of the bidirectional three-terminal thyristor 3, which is not connected to the striking solenoid 2, is 100V
It is connected to the other power supply terminal 5 of the AC power supply.

On the other hand, the power supply terminal 4 includes the cathode terminal 6c of the first unidirectional three-terminal thyristor 6, the cathode terminal 7c of the second unidirectional three-terminal thyristor 7, one end 8a of the first voltage dividing capacitor 8, and the second terminal 8c. One end 9a of the pressure capacitor 9, a cathode terminal 10c of the diode 10, and a cathode terminal 12c of a discharge prevention diode 12 included in the trigger circuit 11 are connected.

On the other hand, the power supply terminal 5 is connected to the other end 13b of the third voltage dividing variable resistor 13, the other end 14b of the fourth voltage dividing variable resistor 14, and the other end 15b of the current limiting resistor 15.
and the other end 16b of the current limiting resistor 16 are connected. The third voltage dividing variable resistor 13 and the fourth voltage dividing variable resistor 14 are mechanically interlocked with each other.

The third voltage dividing variable resistor 13 is connected to the other end 8b of the first voltage dividing capacitor 8 via the first voltage dividing resistor 17.
The gate terminal 6g of the first unidirectional three-terminal thyristor 6 is connected to the connection point.

The fourth voltage dividing variable resistor 14 is connected to the other end 9b of the second voltage dividing capacitor 9 via a second voltage dividing variable resistor 18, and a second unidirectional three-terminal thyristor 7 is connected to the connection point. The gate terminal 7g of is connected.

The turn-on of the second unidirectional three-terminal thyristor 7 is the turn-on of the first unidirectional three-terminal thyristor 6.
The first voltage dividing capacitor 8 and the first voltage dividing resistor 1 are turned on with a slight phase delay L.
7. The capacitance or resistance value of the second voltage dividing capacitor 9 and the second voltage dividing resistor 18 is determined respectively, and the third voltage dividing variable resistor 13 and the fourth voltage dividing variable resistor 14 are is set so that its resistance value is always the same.

If the resistance values of the third voltage-dividing variable resistor 13 and the fourth voltage-dividing variable resistor 14 are increased, the turn-on phase delay of both the unidirectional three-terminal thyristors 6 and 7 increases.

The anode terminal 6a of the first unidirectional three-terminal thyristor 6 is connected to one end 15a of the current limiting resistor 15 and the switching transistor 19.
is connected to the base terminal 19b of.

The anode terminal 7a of the second unidirectional three-terminal thyristor 7 is connected to one end 16a of the current limiting resistor 16, and the switching transistor 19
is connected to the collector terminal 19c of. A trigger pulse generation circuit is constructed using the second unidirectional three-terminal thyristor 7 and the switching transistor 19 as main components.

The emitter terminal 19e of the switching transistor 19 is connected to the anode terminal 10a of the diode 10.
is connected.

The cathode terminal 20c of the third unidirectional three-terminal thyristor 20 is connected to the normally open terminal 22 of the manual trigger switch 21, and the anode terminal 20a of the third unidirectional three-terminal thyristor 20 is connected to the gate terminal of the bidirectional three-terminal thyristor 3. Connected to 3g.

The cathode terminal 20c and gate terminal 20g of the third unidirectional three-terminal thyristor 20 are connected via a resistor 23. A resistor 24 is connected between this resistor 23 and the collector terminal 19c of the switching transistor 19.

The bidirectional three-terminal thyristor 3 has its anode terminal 2 in the third unidirectional three-terminal thyristor 20.
It turns on when a current of constant voltage actually flows from 0a to cathode terminal 20c.

The trigger circuit 11 is composed of a manual trigger switch 21, a double excitation prevention capacitor 25, a resistor 26, and a discharge prevention diode 12. A common terminal 27 of the manual trigger switch 21 is connected to one terminal 25a of the double excitation prevention capacitor 25. , the normally closed terminal 28 of the manual trigger switch 21 is connected to the anode terminal 12a of the discharge prevention diode 12. Anode terminal 12 of discharge prevention diode 12
a and the other terminal 25 of the double excitation prevention capacitor 25
The resistor 26 is connected between the terminal and the terminal b.

The operation of the solenoid control circuit 1 will be described in detail below. When an AC current of 100V is supplied to the power supply terminals 4 and 5, 100V is applied to the gate terminal 6g of the first unidirectional three-terminal thyristor 6.
A current having a voltage exceeding the turn-on voltage of the first unidirectional three-terminal thyristor 6 is supplied for each cycle of the alternating current of 100 V, so that the first unidirectional three-terminal thyristor 6 receives an alternating current of 100 V. It repeats turn-on and turn-off in synchronization with the cycle. (See Figures 2A and 3A).

Similarly to the first unidirectional three-terminal thyristor 6, the second unidirectional three-terminal thyristor 7 is repeatedly turned on in synchronization with the cycle of the 100V alternating current (Figures 2B and 3). (See B).

The turn-on of the second unidirectional three-terminal thyristor 7 is the turn-on of the first unidirectional three-terminal thyristor 6.
There is a slight delay in time compared to on. During this turn-on phase lag L (see FIGS. 2C and 3C), the switch transistor 19 is in the OFF state, and a turn-on voltage is applied to the gate terminal 20g of the third unidirectional three-terminal thyristor 20. A trigger pulse with a pulse width L corresponding to the phase lag L is applied with a voltage exceeding the phase lag L, allowing the gate current required to turn on the third unidirectional three-terminal thyristor 20 to flow.

However, the common terminal 2 of the manual trigger switch 19
No charging current flows from the gate terminal 3g of the bidirectional three-terminal thyristor 3 to the double excitation prevention capacitor 25 unless the normally open terminal 22 and the normally open terminal 7 are connected by operating the electric impact tool.

The moment the common terminal 27 and the normally open terminal 22 of the manual trigger switch 21 are connected, the second
In Figure C, between the falling edge of the first trigger pulse 29 and the falling edge of the second trigger pulse 30 (i.e.
(within one cycle of alternating current).

After the normally open terminal 22 of the manual trigger switch 19 is closed, the third unidirectional three-terminal thyristor 20 is turned on by the second trigger pulse 30, and in this turn-on state, the other power supply terminal 5 is turned on. , a charging current flows to the double excitation prevention capacitor 25 via the resistors 16, 24 and 23.

Turn of the third unidirectional three-terminal thyristor 20
When turned on, a pulsed current flows from the anode terminal 20a to the cathode terminal 20c from the other power supply terminal to the first terminal 3a of the bidirectional three-terminal thyristor 3.
Double excitation prevention capacitor 2 via gate terminal 3g
5 also flows as a charging current. As a result, the bidirectional three-terminal thyristor 3 is turned on, and an exciting current flows through the striking solenoid 2. By changing the resistance values of the third variable voltage dividing resistor 13 and the fourth variable voltage dividing resistor 14, the phase through which this excitation current flows advances (see FIG. (See Figure D). In the case shown in FIG. 2D, the impact force of the driver integrated with the movable iron core of the impact solenoid 2 is small, and in the case shown in FIG. 3D, the impact force of the driver integrated with the movable iron core of the impact solenoid 2. becomes larger.

Charging of the double excitation prevention capacitor 25 is completed within the pulse width L of the second trigger pulses 30 and 32, as shown in FIGS. 2E and 3E, and the charging state is determined by the discharge prevention diode 12. Maintained by blocking reverse current.

The third trigger pulse 33 or 3 is generated by maintaining the charged state of the double excitation prevention capacitor 25.
4 is supplied to the gate terminal 18g of the third unidirectional three-terminal thyristor 20, no pulsed anode current appears in the third unidirectional three-terminal thyristor 20. As a result, the bidirectional three-terminal thyristor 3
remains off, and the striking solenoid 2 is not energized.

Again, common terminal 27 of manual trigger switch 21
When the gap between and the normally closed terminal 28 is closed, one terminal 25a of the double excitation prevention capacitor 25 → common terminal 27 → normally closed terminal 28 → resistor 26 → the other terminal 25b of the double excitation prevention capacitor 25. As the current flows, the charge in the double excitation prevention capacitor 25 is discharged.

As described above, according to the present invention, by charging the double-excitation prevention capacitor and maintaining its charged state, it is possible to guarantee that the striking solenoid is energized only once during one operation of the manual trigger switch, and also to control the timing of excitation. By controlling the phase, the intensity of excitation of the striking solenoid can be changed.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a solenoid control circuit according to the present invention, and FIGS. 2 and 3 are voltage waveform diagrams showing the operation timing of the main components of the solenoid control circuit. The case where the resistance value of the variable resistor is increased is shown, and FIG. 3 shows the case where the resistance value of the voltage dividing variable resistor is decreased. 1... Solenoid control circuit, 2... Impact solenoid, 3... Bidirectional three-terminal thyristor, 4...
One power supply terminal, 5...The other power supply terminal, 6
...First unidirectional three-terminal thyristor, 7... Second unidirectional three-terminal thyristor, 11... Trigger circuit, 12... Discharge prevention diode, 13... Third voltage dividing variable resistor, 14... ...Fourth voltage dividing variable resistor, 19... Switching transistor, 20...
... Third unidirectional three-terminal thyristor, 21 ... Manual trigger switch, 22 ... Normally open terminal, 25 ... Double excitation prevention capacitor, 27 ... Common terminal, 28
...Normally closed terminal, 29, 30, 31, 32, 33 and 34...Trigger pulse, L...Phase delay.

Claims (1)

[Scope of utility model registration request] A solenoid that is connected to both terminals of an AC power supply and is supplied with alternating current through a bidirectional three-terminal thyristor in series, and one unidirectional three-terminal having a rectified output that falls with a variable phase delay in the alternating current. and a unidirectional three-terminal thyristor that generates a rectified output that falls with a constant phase difference L with respect to the fall of the rectified output and generates a trigger pulse having a pulse width L corresponding to the phase difference L. One terminal of the twice-excitation prevention capacitor is connected to the common terminal of a trigger pulse generation circuit that generates synchronized with the phase of the rectified output of the trigger pulse generator, and a manual trigger switch that has a common terminal, a normally open terminal, and a normally closed terminal. The other terminal of the excitation prevention capacitor was connected to the anode terminal of a discharge prevention diode, and the cathode terminal of this discharge prevention diode was connected to one power supply terminal, and the normally closed terminal of the manual trigger switch and the anode terminal of the discharge prevention diode were connected. It consists of a trigger circuit and another unidirectional three-terminal thyristor whose turn-on is controlled by the trigger pulse of the trigger pulse generating circuit, thereby controlling the turn-on of the bidirectional three-terminal thyristor. The cathode side of the three-terminal thyristor is connected to the normally open terminal of the manual trigger switch, and when the common terminal and normally open terminal of the manual trigger switch are connected, other terminals within the pulse width L of the trigger pulse A solenoid control circuit that turns on a directional three-terminal thyristor to charge a double excitation prevention capacitor and simultaneously turns on the bidirectional three-terminal thyristor, thereby exciting the solenoid.