JPH1057328A - Exhauster for hemomanometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out rapid and constant exhaust by using only one exhausting mechanism by using a frequency modulation signal as a regulating signal for regulating an exhausting rate of compressed air in a cuff. SOLUTION: A display 2 is connected to a CPU 1 storing a measuring program of a hemomanometer and the CPU 1 receives a pressure value signal from AD converting circuit 3 and then sends a code signal to a frequency modulation circuit 7 and a pressure signal to a pressurizing apparatus 6. An pressure sensor 4 detects the pressure of a gas in the cuff 5 and sends the sensor signal to the AD converting circuit 3, while the frequency modulation circuit 7 sends a frequency modulation signal and a control signal corresponding to the code signal to an electromagnetic valve driving circuit 8 to drive the electromagnetic valve 9. The electromagnetic valve 9 is driven by the frequency modulation signal and the code signal. The frequency modulation circuit 7 sends the frequency modulation signal and controlling signal according to the code signal output from CPU 1 to drive the electromagnetic valve 9 and to rapidly exhaust at a constant rate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for evacuating a compressed gas at a constant speed and at a high speed, and more particularly to a control of an evacuating device which can be used for a blood pressure monitor.

[0002]

2. Description of the Related Art As one of constant-pressure exhaust mechanisms of a blood pressure monitor in the prior art, there is an apparatus of a mechanism for performing constant-rate exhaust by balancing the pressure of a pressurized cuff and the elasticity of a rubber cylinder. However, this constant speed exhaust mechanism has the following problems. Since the balance between the elasticity of the rubber material and the pressure of the gas is balanced, there is a problem that the adjustment operation is difficult, and the exhaust speed is not stable due to the variation in parts. In addition to such a problem, due to the structure of the exhaust mechanism, a rapid exhaust mechanism is provided separately from the constant-speed exhaust mechanism, so that the apparatus is expensive.

[0003]

To solve the above-mentioned problems of the mechanism described above, Japanese Patent Application Laid-Open No.
As disclosed in Japanese Patent Publication No. 11121, there has been proposed a device for constant-speed rapid exhaust using a piezoelectric element. FIG. 5 shows a constant speed rapid exhaust device using a piezoelectric element. In FIG. 5, piezoelectric elements 53 and 54 are attached so as to sandwich a metal plate 52, thereby forming a piezoelectric element operating member 51. The piezoelectric element operating member 51 is held in a cantilevered state, and can be bent vertically by a drive circuit (not shown). On the other hand, the pressurized gas flows out to the exhaust pipe 56. When the discharge of the gas flowing out to the exhaust pipe 56 is stopped, the piezoelectric element operating member 51 bends downward so that the valve 55 comes into close contact with the exhaust pipe 56 to stop the gas flow. When operating as a constant speed exhaust mechanism, the piezoelectric element operating member 51 is driven at a constant frequency and performs a fine movement operation in the vertical direction. Due to this fine movement, a very small gap is formed between the valve 55 and the exhaust pipe 56, so that a small amount of pressurized gas can be exhausted and constant-speed exhaust can be performed. Further, when operating as a rapid exhaust mechanism, the piezoelectric element operating member 51 bends only in the upward direction, a certain gap is formed between the valve 55 and the exhaust pipe 56, and the gas flowing out of the exhaust pipe 56 is rapidly discharged. Exhausted. Therefore, constant speed and rapid exhaust are possible with this device, and a constant speed rapid exhaust device has been proposed.
However, the piezoelectric element actuating member used in this device is a bonded part of the metal and the piezoelectric element, so that the manufacturing is complicated and expensive.

Accordingly, an object of the present invention is to provide an inexpensive exhaust device which can perform constant-speed rapid exhaust and is inexpensive.

[0005]

In order to achieve the above object, the exhaust system of the present invention employs the following means. An exhaust device of the present invention includes a solenoid valve for exhausting a compressed gas in a cuff at a predetermined speed, a unit for detecting an exhaust speed, and a unit for outputting a signal for controlling the exhaust speed. Wherein a frequency modulation signal is used as a signal for controlling the exhaust speed. Further, the frequency modulation signal is characterized by comprising a plurality of different frequency modulation signals. Furthermore, a plurality of different frequency modulation signals are configured to switch based on a predetermined time.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an exhaust system according to an embodiment of the present invention. FIG. 1 is a block diagram of a sphygmomanometer in which the exhaust device of the present invention is implemented. FIG. 2 is a circuit diagram of a frequency modulation circuit that generates a frequency modulation signal. Table 1 is a truth table of the decoder circuit in the frequency modulation circuit. FIG. 3 is a graph showing a state in which the pressure of the compressed gas passing through the solenoid valve is reduced when the solenoid valve is continuously driven at several frequencies. FIG. 4 is a graph showing a state where the pressure of the compressed gas is reduced by the electromagnetic valve controlled by the frequency modulation signal.

Next, the configuration of a sphygmomanometer in which the exhaust device of the present invention is implemented will be described with reference to FIGS.

FIG. 1 is a block diagram of a sphygmomanometer according to the present invention. As shown in FIG. 1, a display 2 for displaying a blood pressure measurement result and the like is connected to a CPU 1 in which a measurement program of a sphygmomanometer is stored. The CPU 1 receives a pressure value signal from the AD conversion circuit 3, and outputs a code signal to the frequency modulation circuit 7 and a pressure signal to the pressure device 6 from the CPU 1. The AD conversion circuit 3 receives a sensor signal from the pressure sensor 4 and outputs a pressure value signal. The cuff 5, the pressure sensor 4, the pressurizing device 6, and the solenoid valve 9 are connected by an air hose 10. The pressure sensor 4 detects the pressure of the gas in the cuff 5 and sends a sensor signal to the AD conversion circuit 3. The frequency modulation circuit 7 outputs a frequency modulation signal and a control signal corresponding to the code signal and sends them to the solenoid valve driving circuit 8. The solenoid valve driving circuit 8 drives the solenoid valve 9. Solenoid valve 9
Can stop outflow of the compressed gas flowing into the air hose 10 in the ON state. The solenoid valve 9 is driven by a frequency modulation signal and a control signal.

FIG. 2 is a circuit diagram of the frequency modulation circuit 7.
Code input terminals 21 (C1), 22 (C2), 23 (C
3) receives a code signal from the CPU 1. The code signals C1, C2, and C3 are input to the decoder 20, and the decoder 20 outputs Q0, Q1, Q2, and Q corresponding to the code signals.
3. Output a signal to Q4. The truth table of the input / output signals of the decoder 20 is shown in Table 1.

[0010]

[Table 1] The control input of the semiconductor switch 24 is the decoder 20
Of the semiconductor switches 25, 2
The control inputs 6 and 27 are connected to Q3 of the decoder 20,
Connected to Q4 and Q0. Each semiconductor switch 24, 2
The input signal lines 5 and 26 are connected and connected to the output of the inverter 36. The input signal line of the semiconductor switch 27 is connected to the power supply potential (VDD). The resistors 28, 29 and 30 are connected in series. And the semiconductor switch 24
Is connected to one end of the resistor 28, and the output signal line of the semiconductor switch 25 is connected between the resistors 28 and 29. The output signal line of the semiconductor switch 26 is a resistor 29
The output signal line of the semiconductor switch 27 is connected to one end of the resistor 30 and the input of the inverter 34.

The output of inverter 34 is connected to the input of inverter 35, and the output of inverter 35 is connected to inverter 36.
Connected to the input. The output of the inverter 36 is connected to the first input of the OR gate 37. Q of decoder 20
One output is connected to the second input of the OR gate 37. O
The output of the R gate 37 is connected to a control output terminal 38. The capacitor 31 is connected to the input of the inverter 34, and the capacitor 3 is connected to the input terminal of the inverter 35.
2 is connected, and a capacitor 33 is connected to the input terminal of the inverter 36. The other end of each capacitor is connected to GND potential.

The above-mentioned inverters 34, 35, 36, resistors 28, 29, 30, capacitors 31, 32, 33 and semiconductor switches 24, 25, 26 constitute a CR oscillation circuit. When the semiconductor switch 27 is off and any of the semiconductor switches 24, 25, 26 is on,
This CR oscillation circuit enters an oscillating operation state and the inverter 36
An oscillation signal appears at the output of. The frequency of the oscillation signal becomes the highest when the semiconductor switch 24 is turned on, and then becomes lower when the semiconductor switches 25 and 26 are turned on in this order. When Q0 of the decoder 20 is turned on, the input of the inverter 34 is connected to the power supply potential.

Next, the operation of FIGS. 1 and 2 will be described with reference to FIGS.

In a state before the blood pressure measurement is started in this sphygmomanometer, the CPU 1 outputs code signals C1 = L, C2 = L,
C3 = L is output. Upon receiving this code signal, the decoder 20 in the frequency modulation circuit 7 outputs the output Q according to the truth table of Table 1.
Only 0 is set to the logic level H, and only the semiconductor switch 27 is turned on. When the semiconductor switch 27 is turned on, the input of the inverter 34 becomes the logic level H, and the inverter 34 outputs the logic level L. Since the output of the inverter 34 is at the logical level L, the logical level L passes through the inverter 35 and outputs the logical level L to the output of the inverter 36. At this time, since the output Q1 of the decoder circuit 20 is at the logical level L, both inputs of the OR gate 37 are at the logical level L, and the output of the OR gate 37 is also at the logical level L. Then, the control output terminal 38 becomes a control signal of a logical level L, and this control signal turns off (opens) the electromagnetic valve 9 via the electromagnetic valve drive circuit 8. Therefore, the pressure in the cuff 5 is the same as that in the atmosphere.

When the blood pressure measurement of the sphygmomanometer is started, the blood pressure measurement program stored in the CPU 1 is started, and the CPU 1 outputs a pressure signal to the pressure device 6.
The pressurizing device 6 starts to operate and supplies the compressed gas to the air hose 1.
Start feeding into cuff 5 via 0. At this time, CPU
1 outputs code signals C1 = H, C2 = L, C3 = L. Similarly, according to the truth table of Table 1, Q1 of the decoder circuit 20
Only the logic level H is attained, and one input of the OR gate 37 is at logic level H, so that the control output terminal 38 becomes a control signal of logic level H, and the solenoid valve 9 is turned on (closed state).
become. When the solenoid valve 9 is turned on, the gas in the air hose 10 is cut off from the atmosphere, and the gas in the cuff 5 cannot enter the atmosphere. Therefore, the pressure in the cuff 5 increases.

The pressurizing device 6 continues to send the compressed gas to the cuff 5, the pressure sensor 4 detects the pressure of the compressed gas, sends a sensor signal to the AD conversion circuit 3, and the AD conversion circuit 3 converts the sensor signal into a pressure signal. And sent to the CPU 1. The CPU 1 obtains the pressure value of the compressed gas and monitors that the pressure value reaches a set value. When the pressure of the compressed gas increases and the pressure value reaches the set value, the CPU 1 stops the pressurization signal. Accordingly, the pressurizing device 6 stops its operation, and stops sending compressed gas to the cuff 5. The CPU 1 performs the blood pressure measurement process based on the information on the pressure value in a parallel process.

When the CPU 1 stops applying the pressure signal, the frequency modulation circuit 7 supplies the code signals C1 = L, C2 = H, C3 =
Send L. At the time of this code signal, only the Q2 output of the decoder 20 becomes the logic level H according to the truth table of Table 1. Q2
Becomes H, only the semiconductor switch 24 is turned on, and the output of the inverter 36 and one end of the resistor 28 are connected.

From this time, the CR oscillator constituted by the inverters 34, 35, 36 and the like starts oscillating. The resistors 28, 29, and 30 that determine the oscillation time constant resistance of the CR oscillator oscillate in a series connection state, and the oscillation signal has the highest frequency f1 (500 Hz). This frequency f1 (500
Hz) signal from the output of the inverter 36 to the OR gate 3
7, and is output to the control output terminal 38. Then, the electromagnetic valve 9 is driven by the frequency f1 (500 Hz) signal.

Here, if the solenoid valve 9 is set to f1 (500H
When the driving is continued at the frequency of z), the pressure of the compressed gas exhausted by the solenoid valve 9 decreases with the elapse of time according to the curve represented by f1 in FIG. Also, the solenoid valve 9 is set to f2 (3
00 Hz), the frequency f of FIG.
2 (300 Hz), and when it continues to be driven at the frequency of f3 (200 Hz),
It goes down along the curve represented by f3 (200 Hz) in FIG.

Therefore, when the CPU 1 sends the code signals C1 = L, C2 = H, and C3 = L to the frequency modulation circuit 7 for a fixed time T1, the frequency modulation circuit 7 transmits the code f1 (500 Hz) only during the time T1. An oscillation signal is output to the control output terminal 38. Therefore, this oscillation signal drives the solenoid valve 9 from the control output terminal 38 via the solenoid valve drive circuit 8. As a result, the pressure change of the compressed gas exhausted by the solenoid valve 9 is shown in FIG.
T1 time.

During the blood pressure measurement, the CPU 1 sets a predetermined time T
1 is completed, the CPU 1 then outputs the code signal C
1 = H, C2 = H and C3 = L are sent to the frequency modulation circuit 7. The decoder 20 receiving this code signal sets only the Q3 output to the logic level H, and only the semiconductor switch 25 is turned on. The time constant resistance of the CR oscillator at this time is represented by resistors 29 and 3
It becomes a series resistance of 0 and the oscillation frequency is modulated to f2 (300 Hz). From this point on, the solenoid valve 9 starts operating at the frequency f2 (30
0 Hz) and enters a certain time T2 in FIG. As a result, the pressure change of the compressed gas exhausted by the solenoid valve 9 corresponds to the time T2 in FIG.

Next, when the CPU 1 terminates the predetermined time T2, the CPU 1 sets the code signals C1 = L, C2 = L, C3
= H to the frequency modulation circuit 7. Similarly, the decoder 20 turns on only the Q4 output, and the time constant resistance of the CR oscillator becomes only the resistance 30, and the oscillation frequency is f3 (200 Hz).
Is modulated. From this point on, the solenoid valve 9 starts operating at the frequency f3 (2
00 Hz) and enters a certain time T3 in FIG. As a result, the pressure change of the compressed gas exhausted by the solenoid valve 9 is shown in FIG.
T3.

When the blood pressure measurement is completed, the CPU 1 terminates the predetermined time T3. As described above, from time T1 to time T2 and time T3 in FIG. 4, the CPU 1 sets the solenoid valve 9 to the frequency f1 (500 Hz), f2 (300 Hz), f3
By driving with a (200 Hz) frequency modulation signal, constant-speed exhaust shown in FIG. 4 can be performed.

When the blood pressure measurement is completed, the CPU 1 sends the code signals C1 = L, C2 = L and C3 = L to the frequency modulation circuit 7 to return to the same state as before the blood pressure measurement. Then, only the Q0 output of the decoder 20 is turned on, the CR oscillator stops oscillating, and a logical level L is output to the control output terminal 38. Therefore, the solenoid valve 9 is turned off, and the compressed gas in the cuff 5 is rapidly exhausted.

[0025]

As described above, in the embodiment of the present invention, the solenoid valve which has been conventionally used only for rapid exhaust can be used also as a constant-speed exhaust valve by controlling it with a frequency modulation signal. done. The frequency modulation circuit outputs the frequency modulation signal and the control signal in response to the code signal output from the CPU 1 to drive the solenoid valve, thereby enabling constant speed and rapid exhaust. In the present invention, the oscillation frequency of the CR oscillator is from 200 Hz to 500 Hz, but it is from 10 Hz to 10 KHz depending on the response characteristics of the solenoid valve, and control may be performed by a frequency modulation signal in this range. Further, as shown in FIG. 4, three divisions from T1 to T3 are performed for constant-speed exhaust, but it is easy to make three or more divisions for more accurate constant-speed exhaust. The CR oscillator is an example of an oscillation circuit, and may be any circuit that emits an oscillation signal.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a frequency conversion circuit diagram according to an embodiment of the present invention.

FIG. 3 is a graph for explaining an exhaust state when the solenoid valve is driven at a constant frequency in the embodiment.

FIG. 4 is a graph when the solenoid valve exhausts at a constant speed in the embodiment.

FIG. 5 is a conventional constant-speed rapid exhaust device for a blood pressure monitor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 CPU 5 Cuff 6 Pressurizing device 7 Frequency modulation circuit 9 Solenoid valve 10 Air hose 20 Decoder 24 Semiconductor switch 25 Semiconductor switch 26 Semiconductor switch 27 Semiconductor switch

Claims (3)

[Claims] 1. A sphygmomanometer comprising: an electromagnetic valve for exhausting a compressed gas in a cuff at a predetermined speed; means for detecting an exhaust speed; and means for outputting a signal for controlling the exhaust speed. An exhaust device for a sphygmomanometer, wherein a frequency modulation signal is used as a signal for controlling an exhaust speed. 2. The exhaust device for a sphygmomanometer according to claim 1, wherein the frequency modulation signal comprises a plurality of different frequency modulation signals. 3. The exhaust device for a sphygmomanometer according to claim 2, wherein the plurality of different frequency modulation signals are switched based on a predetermined time.