JPH0363373B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention measures blood pressure by pumping gas into the cuff to close the artery, then switching to the exhaust state and exhausting the gas pumped into the cuff. The present invention relates to a constant-speed evacuation device for an automatic blood pressure monitor that lowers cuff pressure at a preset constant rate when performing a blood pressure monitor.

(Prior art) Conventionally, the so-called Riva measures systolic and diastolic blood pressure by wrapping a cuff around the upper arm, pumping air, and detecting Korotkoff sounds generated by arteries.
When using the Rocci method, air is first pumped into the cuff until the artery is occluded, and then the cuff pressure is increased by 2 to 3
A microphone installed in the cuff detects the Korotkoff sound that occurs as the cuff pressure decreases when deflating gradually at a rate of mmHg/sec., and when the Korotkoff sound first occurs, the cuff pressure is adjusted to the systolic pressure. In addition, the cuff pressure when the last Korotkoff sound that occurred during the process of continuous evacuation disappears is measured as the diastolic blood pressure value, and each measured value is displayed on a display device, such as an LED display. An automatic blood pressure measuring device was used.

A normal exhaust valve is generally used as a means to gradually exhaust the cuff pressure at a rate of 2 to 3 mmHg/sec. A method is to apply a predetermined driving current to the exhaust valve and open the exhaust valve to a constant opening. He had been hired.

(Problems to be Solved by the Invention) According to the above-mentioned conventional evacuation means, since the opening degree of the evacuation valve is constant, the evacuation speed is usually fast when the cuff pressure is high, and as the cuff pressure becomes low. Due to the characteristic that the evacuation speed is slow, it has been difficult to reduce the cuff pressure linearly. However, there is a close relationship between the decreasing state of cuff pressure and the systolic and diastolic blood pressure values measured during the cuff pressure decreasing process, and if the pumping speed is too fast, the systolic blood pressure value will be low
The diastolic blood pressure value will be measured too high, and conversely, if the pumping speed is too slow, biological reactions such as depressed blood will occur in the blood pressure measurement artery, which will not only make the blood pressure measurement inaccurate but also interfere with the blood pressure measurement itself. This results in Therefore, when measuring blood pressure, it is an important requirement to decrease the cuff pressure in a linear manner, and the accuracy of the blood pressure measurement value is extremely unstable when measuring blood pressure using the conventional exhaust means, which lacks linearity in the rate of decrease in the cuff pressure. There was a problem that the measured values were not necessarily accurate.

Therefore, in the present invention, in order to reduce the cuff pressure linearly at a preset speed, the cam that drives the valve of the exhaust section is shaped so that the cuff pressure falls linearly, and the cam is By providing a constant speed evacuation device that controls the rotational speed of a rotating motor in accordance with the cuff pressure drop rate, the problems of conventional evacuation means are solved.

(Means for solving the problem) The technical means for solving the above problem is to force gas into the cuff wrapped around the upper arm, etc., close the artery, and then automatically switch to the evacuation state and release the gas into the cuff. An automatic blood pressure measuring device that measures systolic blood pressure and diastolic blood pressure during the process of exhausting the pumped gas is equipped with a pressure section that communicates with the cuff and is formed to obtain a gas pressure equal to the cuff pressure, and a pressure chamber section that communicates with the cuff. an exhaust section having an exhaust valve for exhausting the gas in the cuff at a predetermined speed through the cuff and lowering the cuff pressure at a preset cuff pressure drop rate; a cam that drives the cam; a motor that rotates the cam in accordance with the set cuff pressure lowering speed; a drive control section that outputs a drive signal corresponding to the set cuff pressure lowering speed to the motor; and a setting section that outputs a setting signal corresponding to the set cuff pressure drop rate.

(Function) When the setting section sets the evacuation speed at which gas is evacuated from the cuff, that is, the rate of decrease in cuff pressure, when gas is forced into the cuff to close the artery, the pressure chamber section Pressure equals cuff pressure. When the automatic blood pressure measuring device is automatically switched to the exhaust state in this state, a drive signal corresponding to the set cuff pressure lowering speed is outputted from the drive control section to the motor. The motor rotates the cam, and the cam also drives the exhaust valve of the exhaust section, and controls the exhaust valve to an opening degree corresponding to the set cuff pressure lowering speed. Therefore, the constant speed exhaust system is
By operating the motor and cam, the gas from the cuff is exhausted to the atmosphere from the exhaust valve through the pressure section and the exhaust section at a predetermined exhaust speed, so that the cuff pressure linearly decreases. The systolic blood pressure value and the diastolic blood pressure value are measured in the process of linearly decreasing the cuff pressure.

(Example) Next, an example of the present invention will be described in detail with reference to the drawings.

Figure 1 shows the gas (e.g. air) pumped into the cuff.
FIG. 2 is a front panel installation diagram of an embodiment of an automatic blood pressure measuring device including a constant-speed evacuation device for evacuating the cuff at a predetermined evacuation speed and lowering the cuff pressure at a preset speed.

For example, on the front panel 2 of the automatic blood pressure measuring device 1,
An illuminated push button type power switch 3 for turning on AC100V commercial power is installed, and when the power switch 3 is turned on, the required power is supplied to the electric circuit shown in FIG. 2, which will be described later. When measuring the systolic blood pressure, diastolic blood pressure, and pulse rate of the subject, a measurement number setting switch 4 is used to select how many times to measure the same subject and whether or not to calculate and display the average value of the measured values.
is installed and set to OFF position, measure once, set to 2 position, measure twice, and set to 3 position, measure three times, and then calculate each measured value or The measured average value is displayed on LED indicators 7, 8, 9 and a printer 36 capable of graphical display, which will be described later. The printer 36 may be provided separately from the main body of the automatic blood pressure measuring device 1, or may be built-in. In addition, as shown in the overall system diagram of FIG. 3, a cuff 32 is wrapped around the upper arm 31 and the artery 3
Blood vessel sounds generated from the blood pressure measuring device 1 can be detected by the microphone 34, and gas can be pumped into the cuff 32 through the pipe 35 from a pressurizing pump 41, which will be described later, built into the automatic blood pressure measuring device 1. A start switch 5 is provided which is turned on when starting automatic blood pressure measurement. When the start switch 5 is turned on, gas is pumped into the cuff 32 and to the constant speed exhaust device 51 (described later) until the cuff pressure reaches the set pressure set by the upper limit pressure setting switch 11 (described later), and thereafter, the gas is automatically pumped to a predetermined level. Blood pressure measurements are taken. In addition, if it is necessary to clear the previous measurement data and display data, such as when measuring the blood pressure of another subject or the same subject again,
A reset switch 6 that is turned on is provided. In addition, the systolic blood pressure value displayed on the LED display 7,
The diastolic blood pressure value displayed on the LED display 8, and
If you do not want the patient to see the pulse rate displayed on the LED display 9, turn on the LED display 7,
A blind switch 10 is provided for disabling the display function of the switches 8 and 9. blind switch 1
When 0 is turned on, each measurement value is displayed on the LED display 7,
8 and 9, it is possible to prevent psychological agitation when measuring blood pressure or pulse rate of the subject. The upper limit pressure setting switch 11 is for setting the maximum pressure value of the gas to be pumped to the cuff 32 as described above, and the setting value is, for example,
120mmHg, 150mmHg, 180mmHg, 210mmHg, 240
Each can be set to mmHg. As an operation switch related to the printer 36 for printing out each measurement data of the subject, when the printer 36 prints out the measurement data, it is used to select whether to display it in digital form or in analog form, that is, in graphic form. A display mode changeover switch 12 for selecting a display mode, a copy switch 13 for causing a printer 36 to print a copy, and a paper feed switch 14 for feeding paper to the printer 36 are provided.

In addition, a level meter 15 displays the level of Korotkoff sounds generated from the artery 33 when measuring the blood pressure of the subject, and displays an abnormal state when the timing of the pulse rate generated from the artery 33 is irregular, that is, when an arrhythmia occurs. Irregular indicator light 1
6. An error indicator light 17 for displaying an error when any measurement error occurs during blood pressure measurement; and a voice notification of the systolic blood pressure value, diastolic blood pressure value, pulse rate, and occurrence of arrhythmia when necessary. A speaker SP is provided.
The audio output from the same speaker SP is
When the blind switch 10 is turned on, it is shut off. Cuff pressure drop rate setting switch 1
8 is for setting the speed at which the cuff pressure is lowered when the gas pumped into the cuff 32 is exhausted; for example, the cuff pressure lowering speed is set to 2, 4, 6, 8,
The cuff pressure drop rate can be set to an arbitrary value such as 10 mmHg/sec. In addition to unit time, the cuff pressure drop rate can be set to any value such as 10 mmHg/sec.
It is also possible to use biological information such as rate.

Next, FIG. 2 shows an arithmetic control block diagram of this embodiment, in which a microcomputer CPU, such as a manufacturer's type Z-80, is used as the central part of the arithmetic control function.
The following circuits are connected to the CPU. That is, a real-time clock circuit 20 for supplying clock signals required by the microcomputer CPU, an A/D converter circuit 21,
That is, the output signal of the amplification circuit 22 that amplifies the electrical signal when the microphone 34 detects the blood vessel sound generated from the artery 33 is converted into a digital signal, and the pressure inside the cuff 32 is detected and converted into an electrical signal. A pressure sensor 23 is provided which converts the electrical signal into a signal and outputs it, and a pressure sensor amplification circuit 24 which amplifies the electrical signal output from the pressure sensor 23 is provided to convert the analog signal corresponding to the cuff pressure output from the pressure sensor amplification circuit 24 into an analog signal corresponding to the cuff pressure. An A/D converter circuit 21 equipped with an IC (manufacturer's model ADC0808, for example) that converts into a digital signal and outputs it is connected.
Furthermore, the measurement calculation program necessary for blood pressure measurement,
A storage circuit 25 equipped with a programmable read-only memory P-ROM for storing predetermined data etc. and a storage circuit 26 equipped with a random access memory RAM for temporarily storing measurement calculation data etc. are connected. .

Furthermore, the microcomputer CPU has the manufacturer's model number,
An output interface 27 using 8279IC is provided, and the LED display 7 for displaying the systolic blood pressure value;
It is connected to an LED display 8 for displaying diastolic blood pressure and an LED display 9 for displaying pulse rate, and outputs a display signal outputted from the microcomputer CPU. Further, a voice synthesis circuit AME is connected to the microcomputer CPU to notify the systolic blood pressure value, diastolic blood pressure value, pulse rate, and occurrence of arrhythmia by voice when necessary. This speech synthesis circuit
For example, the AME uses a ROM memory, outputs a digital signal corresponding to the audio from the ROM memory according to the address specification of the microcomputer CPU, and converts the digital signal into an analog signal using a D/A converter circuit DAC. The circuit is configured such that the analog signal is amplified by the next amplifier circuit AMP, and then the speaker SP is energized to output the sound from the speaker SP.

Furthermore, an input/output interface 28 equipped with, for example, a manufacturer's model 8255IC is connected to the microcomputer CPU for signal communication between the printer 36 and the microcomputer CPU;
A printer interface 29 is provided between the input/output interface 28 and the printer 36 to serially transmit printer signals.

Another input/output interface 30 equipped with an 8255 IC of the same type as described above is further connected to the microcomputer CPU, and the input/output interface 30 can set the number of measurements according to the address command and input/output command of the microcomputer CPU. The microcontroller receives signals output from each of the switch 4, start switch 5, reset switch 6, blind switch 10, upper limit pressure setting switch 11, display mode changeover switch 12, copy switch 13, and cuff pressure lowering speed setting switch 18. Along with transmitting to the computer CPU,
The display signal output from the microcomputer CPU is received and relayed to the irregular indicator light 16 and error indicator light 17.

The input/output interface 30 also includes a pressurizing pump 41 that pumps gas into the cuff 32.
A pressurizing pump drive circuit 42 for driving the pressurizing pump 41 is connected thereto, and a quick exhaust valve driving circuit for driving a quick exhaust valve 43 for rapidly exhausting the gas pumped by the pressurizing pump 41 from within the cuff 32. 44
and a stepping motor drive circuit 46 that drives a stepping motor 45, which will be described later, forming a constant speed exhaust device for exhausting the pressurized gas from inside the cuff 32 at a predetermined exhaust speed.

The programmable read-only memory P-ROM of the memory circuit 25 stores the pulse rate of the subject and the respective lowering speeds of 2, 4, 6, 8, and 10 mm set by the cuff pressure lowering speed setting switch 18.
A program table for determining the frequency of the drive signal for the stepping motor 45 determined by Hg/sec. is stored.

FIG. 3 shows the entire system of this embodiment as described above, in which the cuff 32 is wrapped around the upper arm 31 of the subject, and gas is pumped into the cuff 32 from the pressurizing pump 41 to blood the artery 33. A printer 36 detects blood vessel sounds generated from the artery 33 with a microphone 34 from a state in which the flow is stopped, starts measurement, and types out various measurement data including systolic blood pressure values and diastolic blood pressure values after completion of a predetermined measurement. This figure shows the state in which the device is connected to the automatic blood pressure measuring device 1.

Next, gas is pumped into the cuff wrapped around the upper arm, etc. to close the artery, and then the state is switched to the exhaust state, and the gas pumped into the cuff is controlled by the cuff pressure lowering speed setting switch 18.
The configuration of the constant-speed exhaust device 51 for performing constant-speed exhaust at a preset cuff pressure drop rate will be explained with reference to FIGS. 4 and 5.

As shown in the figure, the gas pumped from the pressure pump 41 is connected to the pipe 5 so that it can be pumped to the pressure chamber 52 of the constant speed exhaust device 51 via the four-cylinder manifold 48.
3 to an inlet 54 of the pressure chamber 52. As shown in FIG. 5, the gas introduced from the inlet port 54 passes through a tube 55 made of a flexible and airtight material, accumulates pressure in an inner cylinder 56 made of aluminum, for example, and is discharged inside the inner cylinder 56. Gradually increase the atmospheric pressure.

One end of the tube 55 is airtightly attached to the inner step of the lower lid 57 to which the introduction port 54 is attached, while the other end is airtightly attached to the lower end of the inner cylinder 56. The tube 55 is folded back to the outside of the inner tube 56 over almost the entire length of the inner tube 56 with both ends attached in an airtight manner as described above, and then the outer tube 58 is attached to the outside of the tube 55. Further, the lower lid 57 is fitted and fixed to the lower end of the outer cylinder 58.

A first spring 59, one end of which is attached to the lower lid 57, is inserted into the inner cylinder 56, and the other end of the spring 59 is in contact with the inner diameter surface of the inner cylinder 56 at the center in the axial direction. It is attached to the center of a disk-shaped movable plate 60 that is attached in a semi-fixed state to. The movable plate 60
A plurality of holes 60H for allowing gas to flow are arbitrarily formed in the spring 59, and a central axis 60S is formed at the center of the end surface opposite to the end surface to which one end of the first spring 59 is attached. Concentric axis 60S
A small diameter hole 60C is bored through the axial center of the shaft. The same small diameter hole 60C has a conical valve 6 in the middle part.
The proximal shaft 61SB of the needle valve 61 having a voltage of 1V is slidably inserted therein.

Further, one end of a second spring 62 is attached to the center shaft 60S, and the other end of the second spring 62 is connected to the valve 60 through a washer 63.
1V, and the second spring 62
When the tip of the valve 61V comes into close contact with a small-diameter exhaust hole 64H formed in the center of the exhaust cover 64 and communicating with the atmosphere due to the repulsive force, the pressurized gas in the inner cylinder 56 is discharged into the atmosphere. to prevent Also,
The tip end shaft 61ST of the needle valve 61 is always projected outside the exhaust hole 64H. Note that the exhaust lid 64 is fixed to the inner diameter portion of the upper end of the inner cylinder 56.

As the gas pressure-fed from the pressure pump 41 is accumulated in the pressure chamber 52, the tube 55 expands and pushes the inner cylinder 56 upward. At this time, the inner cylinder 56 is pushed up to a position where the air pressure in the pressure chamber 52 and the tensile force of the first spring 59 are balanced, and the tip position of the tip side shaft 61ST of the needle valve 61 also moves up by the same distance. .

On the other hand, the cam 65 is attached to the output shaft of the stepping motor 45, and when a driving current is applied to the stepping motor 45 from the stepping motor drive circuit 46 and the motor 45 rotates, the cam 65 is attached to the tip of the needle valve 61. It rotates in contact with the shaft 61ST to linearly move the needle valve 61. When the cam 65 linearly moves the needle valve 61 against the repulsive force of the second spring 62, that is, as the shaft 61ST is pressed inward of the exhaust lid 64 by the cam 65, the valve 61
V gradually increases the exhaust area of the exhaust hole 64H and exhausts the gas in the cuff at a predetermined speed.
Decrease cuff pressure at a constant rate.

Note that the outer cylinder 58 and the stepping motor 45
In order to integrally assemble the two, a mounting bracket 66 made of, for example, an aluminum angle and plate is used. The bracket 66 is also used as a fixing aid for fixing the constant speed exhaust device 51 at a predetermined position within the automatic blood pressure measuring device 1.

Next, the operation of this embodiment will be explained according to the flow chart shown in FIGS. 6-1 to 6-3.

Wrap the cuff 32 around the upper arm 31 of the subject, and further,
By inserting the power plug etc. of the automatic blood pressure measuring device 1 into a commercial power outlet and turning on the power switch 3, the state of each circuit including the microcomputer CPU is initialized. Next, as a preparatory operation for blood pressure measurement, the number of measurements is set with the measurement number setting switch 4, the upper limit cuff pressure of the cuff 32 is set with the upper limit pressure setting switch 11, and the blood pressure measurement value is set with the blind switch 10. and setting whether or not the occurrence of arrhythmia is to be displayed on the LED indicators 7, 8, 9 and irregular indicator light 16, or whether or not the above measurement value and the occurrence of arrhythmia are to be notified by voice, and further,
The cuff pressure fall rate is set by the cuff pressure fall rate setting switch 18. After the above preparation operations are completed, by turning on the start switch 5, the microcomputer CPU reads the set values and setting status signals. Next, the microcomputer CPU reverses the stepping motor 45 to release the contact between the cam 65 and the needle valve 61, closes the constant speed exhaust device 51 and the rapid exhaust valve 43, and then drives the pressurizing pump 41. do. When gas is pumped from the pressure pump 41 into the cuff 32 via the pipe 35 and into the pressure chamber 52 via the pipe 53, the pressure sensor 23 sequentially detects the cuff pressure, and A/ An analog signal corresponding to the cuff pressure is output to the D converter circuit 21. The A/D converter circuit 21 converts an analog signal corresponding to the cuff pressure into a digital signal and outputs it to the microcomputer CPU. The microcomputer CPU inputs a digital signal corresponding to the cuff pressure, converts it into a display signal, and causes the LED display 7 to sequentially display the cuff pressure value.

Next, the microcomputer CPU
In order to determine whether the cuff pressure of No. 2 is increasing normally, it is determined whether it has reached 100 mmHg within, for example, 5 seconds from the start of pressurization of the cuff 32,
If the value has not been reached, the error indicator light 17 is turned on, the rapid exhaust valve 43 is opened and the exhaust is rapidly exhausted, and an error message is typed out using the printer 36. On the other hand, within 5 seconds from the start of pressurizing the cuff 32, 100 mmHg
If it is determined that the pressure has been reached, the pressurizing pump 41 is stopped. Next, depending on whether the blind switch 10 is set to ON or OFF in the preparatory operation, the LED displays 7, 8, and 9 may or may not display the systolic blood pressure value, diastolic blood pressure value, and pulse rate. After determining whether or not to notify the measured value and the occurrence of arrhythmia by voice, the microcomputer CPU moves from the microphone 34 to the amplifier circuit 22 to the A/C without operating the constant speed exhaust device 51 for 2 seconds. D converter circuit 2
The blood vessel sounds of the subject inputted via step 1 are recognized, and it is determined whether the blood vessel sounds include Korotkoff sounds. After this, the flowchart continues from 1-A in FIG. 6 to 2-A in FIG.

In 2 of Fig. 6, in order to avoid the influence of extraneous noise, etc., even if the microcomputer CPU determines that Korotkoff sounds are included in blood vessel sounds, the microcomputer CPU ignores the Korotkoff sounds for one second, and then proceeds to the next decision step. If it is determined that the Korotkoff sound K has occurred during STA, it is determined that the subject's artery 33 is not occluded, and the
In order to pressurize the cuff 32, the rapid exhaust valve 43 is once opened to cause rapid exhaust. micro computer
The CPU determines whether the cuff pressure of the cuff 32 has reached, for example, 10 mmHg, and when determining that it has decreased to 10 mmHg, if the upper limit pressure is set to 210 mmHg by the upper limit pressure setting switch 11 in the preparation operation, Further, the value obtained by adding 30 mmHg is set in the RAM of the memory circuit 26 as the upper limit pressure. Furthermore, it is determined whether the new upper limit pressure value obtained by adding 30 mmHg to this pressure value 210 mmHg does not exceed a preset absolute upper limit pressure, for example, 270 mmHg, and if it is within 270 mmHg, then Make it return. If the upper limit pressure value + 30 mmHg set by the upper limit pressure setting switch 11 exceeds the absolute upper limit pressure, the error indicator light 17 will light up, the quick exhaust valve 43 will be opened to cause rapid exhaust, and a voice will be displayed. The occurrence of an error is notified, and then an error message is printed out from a printer 36.

If it is determined in the determination step STA that the Korotkoff sound is not observed, the microcomputer CPU determines that the condition for blood pressure measurement has been reached, searches the program table stored in the memory circuit 25, and performs stepping. motor 4
After determining the frequency of the drive signal for the stepping motor drive circuit 46, a drive signal of the same frequency is output to the stepping motor drive circuit 46. Stepping motor drive circuit 4
6 drives the stepping motor 45 by applying a drive current corresponding to the same drive signal, rotates the cam 65 to press the needle valve 61, and sets the constant speed exhaust device 51 to the exhaust state to maintain the cuff pressure at a predetermined level. descend at speed. During this constant-speed evacuation process, the microcomputer CPU recognizes blood vessel sounds, and when the first Korotkoff sound is detected, it recognizes the cuff pressure detected by the pressure sensor 23 as the systolic blood pressure value, and displays the LED display. 7 is displayed as the systolic blood pressure value (SYSTOLIC). after that,
Continue to recognize vascular sounds and confirm the occurrence of Korotkoff sounds. After confirming that the Korotkoff sounds that had been occurring until now have disappeared from the blood vessel sounds, and also confirming that the blood vessel sounds without Korotkoff sounds continued for three beats, the microcomputer CPU , the cuff pressure detected by the pressure sensor 23 is recognized as the diastolic blood pressure value. The value recognized as the diastolic blood pressure value is displayed on the LED display 8 as the diastolic blood pressure value (DIASTOLIC), and the pulse rate is further displayed on the LED display 9.

After this, the flow chart continues from 2 in 2 in FIG. 6 to 2 in 3 in FIG. 6, and the systolic blood pressure value measured for the speech synthesis circuit AME,
Outputs a voice output command signal for outputting the diastolic blood pressure value and pulse rate in voice. After recognizing the systolic blood pressure value, the diastolic blood pressure value, and the pulse rate as described above, it is determined whether or not there is an arrhythmia (IRREGULAR). If the occurrence of an arrhythmia is recognized, the irregular indicator light 16 is turned on, and , outputs a voice output command signal to the voice synthesis circuit AME to cause it to output a voice indicating that an arrhythmia has occurred. If no arrhythmia is observed,
If the number of measurements set by the measurement number setting switch 4 is 1, the current measurement information is sent to the printer 36.
Print out in digital display format or analog display format, that is, numbers or graphs. If the number of measurements set by the number of measurements setting switch 4 is 2 or 3, return to step 1B in FIG. The value is calculated and displayed on the LED display.

(Effects of the Invention) As described above, according to the present invention, gas is forced into the cuff wrapped around the upper arm, etc. to close the artery, and then automatically switched to the exhaust state to exhaust the gas forced into the cuff. When measuring systolic blood pressure and diastolic blood pressure during the process, the constant-speed exhaust device is activated to exhaust gas from within the cuff at a predetermined rate, allowing the cuff pressure to drop linearly. This has the effect that the blood pressure value and the diastolic blood pressure value can be accurately measured.

[Brief explanation of drawings]

FIG. 1 is a front panel instrument layout diagram of an automatic blood pressure measuring device according to an embodiment of the present invention, FIG. 2 is a calculation control block diagram of this embodiment, FIG. 3 is an overall system diagram of this embodiment, and FIG. The figure is an overall external view of the exhaust system, Figure 5 is a detailed view of its part, and Figure 6 1 to Figure 6 3.
is a flowchart diagram showing the operation of this embodiment. 1... Automatic blood pressure measuring device, CPU... Microcomputer, 18... Cuff pressure drop setting switch, 23... Pressure sensor, 25, 26... Memory circuit, 31... Upper arm, 32... Cuff, 33... Artery, 34... Microphone, 41... Pressure pump, 45... Stepping motor, 46... Stepping motor drive circuit, 61... Needle valve,
65...cam.

Claims (1)

[Scope of Claims] 1. When gas is forced into a cuff wrapped around the upper arm or the like to close an artery, the system automatically switches to the exhaust state and measures the systolic blood pressure and diastolic blood pressure in the process of exhausting the gas in the cuff, A constant speed evacuation device for an automatic blood pressure monitor for evacuation of gas in the cuff at a preset constant rate, the device being pressurized to the same pressure as the cuff pressure by the gas pumped from the pressurizing pump. A pressure chamber communicating with the cuff, an exhaust valve that exhausts the gas fed to the pressure chamber, a cam that drives the exhaust valve to exhaust the gas from the pressure chamber, and a cam that rotates the cam. a variable speed motor, a drive circuit for supplying a drive current to the motor, setting an evacuation speed for evacuation of the gas in the cuff, and outputting a signal corresponding to the set evacuation speed to the drive circuit; A constant speed exhaust device for an automatic blood pressure monitor, comprising: a setting unit that rotates the motor at a rotational speed such that gas in the cuff is exhausted at the set exhaust speed.