JPS6133582B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an output control device for a dental handpiece in which the output is adjusted by operating a footswitch.

It is necessary to adjust various outputs of a dental handpiece, such as rotational speed and ultrasonic output, depending on the content of the treatment or procedure. For example, in the case of an ultrasonic scaler, in addition to a foot switch with an on/off function, there are also those that have an output adjustment knob on the control device, or those that have an on/off switch and an output adjustment operation part on the handpiece body. Generally speaking, in the former case, the operator must change his or her treatment posture each time the output is adjusted, which increases the operator's fatigue level and reduces efficiency.
In the case of the latter, the structure is not such that the output can be adjusted with one hand without changing the treatment posture, and therefore, like the former, the operability is poor and inefficient.

In the case of a micromotor that drives a cutting tool, a foot controller incorporating a variable resistor for speed adjustment is used to control the output, that is, the rotational speed of the micromotor, by adjusting the amount of foot pedal depression. There are devices that allow adjustment without changing the treatment posture, but it is necessary to continue the treatment while concentrating not only on the hands but also on the feet, and maintaining the appropriate amount of pressure for a long time can cause fatigue. Therefore, it is not suitable as a means for adjusting the output of a scaler, especially for a scaler whose operating time is longer than that of a micromotor.Furthermore, the foot controller becomes large and expensive due to the built-in variable resistor. There is also a problem.

The present invention has been devised to address these conventional problems and to provide an output control device for a dental handpiece that can easily adjust the output by operating a foot switch. a footswitch operated by a person;
Activated by pressing the footswitch, the output signal changes from the initial value to increase or decrease while the footswitch is pressed, and when the footswitch is released, the output signal is maintained at the current state by square wave oscillation. an output adjustment circuit consisting of a circuit, a chattering prevention circuit, and a control voltage output circuit; an oscillation unit whose driving output is controlled by the output signal of the output adjustment circuit; a driver; a transistor; an output transformer; a current detection circuit; and an electrostrictive circuit. It is characterized by being equipped with a handpiece drive circuit consisting of a vibrator, a phase shifter, a main power supply circuit, and a control power supply circuit. As the foot switch mentioned above, an on/off switch with a simple structure that only has an on/off function can be used. For example, the output can be adjusted to an arbitrary level by adjusting the length of the on time when the foot is pressed. The operator only needs to pay attention to the feet while adjusting the output.
After the desired output is obtained, it is possible to release the pressure and concentrate on the hands, and there is no need to change the treatment posture to adjust the output, allowing for efficient treatment with less fatigue. It is.

Next, a few embodiments of the present invention will be described with reference to the drawings. In all of these examples, the present invention is implemented in an ultrasonic scaler.

In FIG. 1, 1 is a foot switch, 2 is an output adjustment circuit, 3 is a handpiece drive circuit, 4 is a square wave oscillation circuit, 6 is a chattering prevention circuit, 5 is a control voltage output circuit, and 7 is an indicator circuit. In the embodiment, the handpiece drive circuit 3 is a drive circuit for driving an electrostrictive vibrator for generating ultrasonic waves. The foot switch 1 is a normal on/off switch that is turned on by pressing the foot switch.
The output adjustment circuit 2 is composed of a square wave oscillation circuit 4, a chattering prevention circuit 6, a control voltage output circuit 5, etc. The control voltage output circuit 5 is a counter IC element.
IC ₅ , operational amplifier IC ₂ , IC ₃ , resistor r ₁₂ ~ r ₁₆ , r ₂₂ ~
r ₂₄ , variable resistor VR ₂ , diodes D ₆ to D ₁₀ , etc. In the counter IC element IC ₅ , in the clear state, only the output terminal A ₀ is at a high potential, and the other output terminals A _{1 to A 1} are at a high potential.
_A4 is at a low potential, and every time a square wave is input from the square wave oscillation circuit 4, the high potential output point changes to _A0.
→A ₁ →A ₂ →A ₃ →A ₄ . The output of this counter IC element IC ₅ is a resistor connected through diodes D ₆ to _{D 10} for blocking reverse current.
The voltage is divided by r ₁₂ to _{r 16} and sent to the handpiece drive circuit 3 via the operational amplifier IC ₂ forming a buffer amplifier.

The handpiece drive circuit 3 includes an oscillator 31, a driver 32, transistors _Tr1 to _Tr3 , an output transformer _T1 , a current detection circuit 33, an electrostrictive vibrator P, a phase shifter 34, a main power circuit 38, and a control power circuit 39. By alternately switching the output of the oscillator 31 with the transistors Tr ₁ and Tr ₂ via the driver 32, the electrostrictive resonator P connected to the output side of the output transformer T ₁ is driven. be. In the oscillation section 31, a voltage controlled oscillator 37 is controlled by a phase detector 35 via an amplifier circuit 36, and a driving voltage of the electrostrictive vibrator P is extracted via a current detection circuit 33. returns a control signal corresponding to the drive current to the phase detector 35;
It is configured such that the driving frequency and the resonant frequency of the electrostrictive vibrator P always match. The phase shifter 34 is for adjusting the phase between the control signal corresponding to voltage and the control signal corresponding to current to an optimum value.
Transistor Tr ₃ adjusts its base current to increase its collector current, that is, main power circuit 3
Output transformer T ₁ from 8 through relay contact RSW
It is for output control to adjust the current supplied to the primary winding, and the output signal of the output adjustment circuit 2 is supplied to the base via resistor _R25 and variable resistor _VR1 for output level adjustment. There is. 39 is a control power supply circuit. Square wave oscillation circuit 4 is an operational amplifier
Consisting of IC ₁ , capacitor C ₁ , and resistors R ₈ to R ₁₁ , when transistor Tr ₅ in the previous stage is inactive, resistors r ₈ to r ₁₁
A square wave is oscillated at a period determined by the capacitor C ₁ and the output thereof is input to the counter IC element IC ₅ of the control voltage output circuit 5 in the next stage. The chattering prevention circuit 6 is composed of a time constant circuit consisting of a resistor _r17 and a capacitor _C3 , and a hysteresis comparator consisting of resistors _r18 to _r20 and an operational amplifier _IC4 .
This functions to absorb chattering when the foot switch 1 is opened and closed, thereby preventing malfunctions.
The indicator circuit 7 displays the level of output of the scaler by emitting LED light, and LED ₁
~ _LED5 is a light emitting diode, _r1 ~ _r5 are resistors for current limiting, _D1 ~ _D5 are diodes for reverse current blocking,
INV ₁ to INV ₅ are buffer inverters provided to allow sufficient current to flow through the light emitting diodes LED ₁ to _{LED 5} , Tr ₄ is a transistor, and r ₀ is a resistor.
Each inverter INV ₁ to INV ₅ is a control voltage output circuit 5
are connected to the output terminals A ₀ to _{A 4} of the counter IC element IC ₅ , respectively. IC ₆ is a flip-flop IC
element, Tr ₆ is a transistor, RL is a relay, r ₆ ,
r ₇ , r ₂₁ , r ₂₆ are resistors, and C ₂ is a capacitor.

Next, the overall operation will be explained. Now, when the power switch (not shown) is turned on, the capacitor
The flip-flop IC element IC ₆ is reset by the time constant circuit of C ₂ and resistor r ₂₆ , and the transistor Tr ₆
and the relay RL inserted in its collector circuit
becomes inactive and the relay contacts of relay RL
RSW is open and handpiece drive circuit 3 is not driven. Further, by resetting the IC element _IC6 , the clear input of the counter IC element _IC5 becomes active, and only the output terminal _A0 of the IC element _IC5 is set to a high potential. On the other hand, the transistor Tr ₅ has a resistance r ₆ ,
Conductive via _r7 , the capacitor _C1 of the square wave oscillation circuit 4 is always at a low potential, and oscillation is stopped.

Here, when the foot switch 1 is depressed and turned on, the signal is inputted to the flip-flop IC element IC ₆ via the chattering prevention circuit 6, and the output Q is inverted. This allows the transistor
Tr ₆ and relay RL are now active and the relay contacts
The RSW closes, the handpiece drive circuit 3 operates, and the electrostrictive vibrator P is driven. At the same time, the counter IC element IC ₅ is cleared, and the base of the transistor Tr ₅ becomes ground potential due to the foot switch 1 being turned on, so that the transistor Tr ₅ becomes non-conductive, and the square wave oscillation circuit 4 connects the resistors r ₈ to _{r 11} ,
Starts oscillation at a period determined by capacitor _C1 . The output potential of the operational amplifier IC ₂ connected to the base circuit of the output control transistor Tr ₃ of the handpiece drive circuit 3 via the variable resistor VR ₁ and the resistor R ₂₅ is the same as that of the IC element IC ₅ when the foot switch 1 is first depressed.
Since the output terminal A ₀ of is at a high potential, if this potential is V, then r ₁₆ / (r ₁₂ + r ₁₃ + r ₁₄ + r ₁₅ +
r ₁₆ )×V, but each time a signal is input from the square wave oscillation circuit 4 to the IC element IC ₅ as time passes, the high potential point of the output terminal changes from A ₀ →A ₁ →A ₂ ……→
As _a result, the output potential of operational amplifier IC ₂ is r ₁₆ / (r ₁₂ + r ₁₃ + r ₁₄ + r ₁₅ + r ₁₆ ) × V →
r ₁₆ / (r ₁₃ + r ₁₄ + r ₁₅ + r ₁₆ ) × V → r ₁₆ / (r ₁₄ + r ₁₅
+r ₁₆ )×V...→V. Therefore, the collector current of the transistor _Tr3 also increases stepwise, and the output of the electrostrictive vibrator P increases stepwise as shown in FIG. 5a. The pitch of this increase corresponds to the oscillation cycle of the square wave oscillation circuit 4. In this embodiment, the output is changed in five steps.

When foot switch 1 is pressed in this way, the resistance
The output of the electrostrictive vibrator P increases at a rate determined by the resistance values of r ₁₂ to _{r 16} and at a speed determined by the oscillation period of the square wave oscillation circuit 4, but in the middle of this, the pedal is released and the foot switch 1 is When opened, the transistor Tr ₅ becomes conductive and the square wave oscillation circuit 4 stops oscillating. Then, the counter IC element IC ₅ maintains the output state at that time, the output signal of the output adjustment circuit 2 stops changing, and the output of the handpiece drive circuit 3 has the magnitude when the foot switch 1 is released. It will be maintained. Therefore,
By adjusting the depression time of the foot switch 1, an arbitrary handpiece output can be obtained, and the operator can control the treatment area in the oral cavity or the object to be removed, i.e., dental calculus, by simply operating the foot without changing the treatment posture. The output of the ultrasonic scaler can be selected depending on the type and amount of plaque, gunk, etc. As mentioned above, the pitch at which the output increases stepwise is determined by the oscillation period of the square wave, so this oscillation period must be selected at a value that allows the operator to easily adjust the output. For example, approximately 0.5 seconds is appropriate. It is believed that there is.

Next, when the foot switch 1 is depressed again, the signal is input to the flip-flop IC element IC ₆ via the anti-chattering circuit 6, the output Q of IC ₆ is inverted again, the relay RL becomes inactive, and at the same time the counter IC The element IC ₅ is also cleared and only the output terminal A ₀ is reset to a high potential state, the relay contact RSW is opened, the operation of the handpiece drive circuit 3 is stopped, and the device returns to the initial standby state. The circuit composed of the operational amplifier IC ₃ , the resistors _r22 to _r24 , and the variable resistor _VR2 of the control voltage output circuit 5 is for determining the upper limit of the output, and the inverting input potential of the operational amplifier _IC3 is connected to the resistor. r ₂₂ ,
r ₂₃ is adjusted by the variable resistor VR ₂ , and when the output potential of the operational amplifier IC ₂ applied to the non-inverting input becomes larger than this potential, the output of the operational amplifier IC ₃ is inverted, and the transistor Tr ₅ is activated to generate a square wave. The oscillation of the oscillation circuit 4 is stopped so that the output stage does not proceed any further. The values of the resistors r ₂₂ and r ₂₃ are determined by the fact that when the variable resistor VR ₂ is fully adjusted to the ground side, the output of the operational amplifier IC ₃ is inverted in the first stage.
The value is selected so that output reversal does not occur until the fifth stage when the power supply side is fully adjusted.

FIG. 2 shows a modification of the above-described embodiment in which the output is reduced in stages.
The output terminals A ₀ to _{A 4} of the counter IC element IC ₅ of the control voltage output circuit 5 are connected in the reverse order from that in FIG. Therefore, in this case, the output of the electrostrictive vibrator P decreases stepwise as shown in FIG. 5b, but other operations are the same as in the case of FIG. 1.

The output adjustment can not only be changed stepwise as in each of the above-mentioned embodiments, but also be changed continuously. FIG. 3 shows the main part of an embodiment in which the output is changed continuously in this way.

In this example, the control voltage output circuit 5 is an operational amplifier.
It is composed of IC ₇ , IC ₈ , and variable resistor VR ₃ , and a circuit including transistors Tr ₇ , Tr ₈ , resistors r ₂₇ to r ₂₉ , capacitor C ₄ , Zener diode ZD, etc. is provided at the front stage.

When the power switch (not shown) is turned on, the flip-flop IC is connected by capacitor C ₂ and resistor r ₂₆ .
Element IC ₆ is reset, relay L becomes inactive, transistor Tr ₈ becomes active, and the non-inverting input, ie, the output, of operational amplifier IC ₇ having a buffer amplifier configuration is maintained at approximately zero. Next, when foot switch 1 is depressed and turned on,
The signal is passed through the chattering prevention circuit 6 to the IC.
It is input to element IC ₆ , output Q is inverted, and relay RL becomes active, and at the same time transistor Tr ₈
becomes inactive. As a result, the resistances r ₂₇ , r ₂₈ ,
Capacitor C ₄ is charged by a constant current circuit composed of Zener diode ZD and transistor Tr ₇ , and the charging potential of capacitor C ₄ , that is, the output of operational amplifier IC ₇ increases continuously and linearly with the passage of time.

Furthermore, when the foot switch 1 is released, charging of the capacitor C ₄ is stopped, and the capacitor potential, that is, the output of the operational amplifier IC ₇ , is maintained at the value at that time, and when the foot switch 1 is pressed again, the capacitor C 4 stops charging.
The output Q of IC element IC ₆ is inverted again, and relay RL
At the same time as becomes inactive, transistor Tr ₈ becomes active, and capacitor C ₄ is discharged and reset to the initial standby state. Therefore, if the output of the operational amplifier IC ₈ of the control voltage output circuit 5 is connected to the variable resistor VR ₁ shown in FIG.
As shown in Figure c, the output increases continuously and linearly, and by releasing the foot switch 1 and opening the foot switch 1, the output is maintained at the current value.

The control voltage output circuit 5 in Figure 3 is an operational amplifier IC ₇
The output is outputted through an operational amplifier IC ₈ having a buffer amplifier configuration, but as shown in Figure 4, the output is output from an operational amplifier through an inverting amplifier consisting of resistors r ₃₂ to r ₃₅ , variable resistor VR ₃ , and operational amplifier IC ₈ . It is also possible to extract the output of IC ₇ . In this case, the maximum output is obtained when the foot switch 1 is depressed, and the output decreases continuously as the depression time elapses, so the control voltage output circuit 5 in Fig. 3 can be replaced with the one in Fig. 4. As a result, output characteristics as shown in FIG. 5d can be realized.

As is clear from the description of each example above,
The present invention provides an output adjustment circuit configured such that when the footswitch is depressed, the output signal changes from an initial value to an increasing direction or a decreasing direction, and when the footswitch is released, the output signal is maintained at the current state. The operator can adjust the output of the handpiece as desired by simply operating the foot switch with his or her foot without changing his or her treatment posture, and the foot switch can be simply an on/off switch, so the structure is simple and easy to operate. and
It has the advantage of reducing fatigue and enabling efficient treatment, and can be applied to the output adjustment of various dental handpieces, not just the ultrasonic scaler shown in the example, with great effects. be. That is, it goes without saying that if a micromotor drive circuit is used in the handpiece drive circuit 3 of the embodiment, it can be used to control the output of the micromotor.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of one embodiment of the present invention, Fig. 2 is a circuit diagram of a main part of another embodiment, Fig. 3 is a circuit diagram of a main part of another embodiment, and Fig. 4 is a circuit diagram of a main part of another embodiment. FIGS. 5a to 5d are circuit diagrams of main parts of the embodiments, and FIGS. 5a to 5d are output characteristic diagrams of each embodiment. [Explanation of symbols], 1...foot switch, 2...
...output adjustment circuit, 3...handpiece drive circuit,
P...Electrostrictive vibrator, RL...Relay, RSW...Relay contact.

Claims (1)

[Claims] 1 Footswitch 1 operated by the operator
It is activated by depressing foot switch 1,
A square wave oscillation circuit 4 and a chattering prevention circuit 6 are provided so that the output signal changes from an initial value to an increasing direction or a decreasing direction while the foot switch 1 is being depressed, and the output signal is maintained at the current state when the foot switch 1 is released. , an output adjustment circuit 2 consisting of a control voltage output circuit 5, an oscillation section 31 whose driving output is controlled by the output signal of the output adjustment circuit 2, a driver 32, and a transistor _Tr1.
~ A dental clinic characterized by comprising a handpiece drive circuit 3 consisting of Tr ₃ , an output transformer T ₁ , a current detection circuit 33 , an electrostrictive vibrator P, a phase shifter 34 , a main power supply circuit 38 , and a control power supply circuit 39 handpiece output control device.