Apparatus for driving medical appliances

Abstract

A self-propelled wheelchair type artificial heart driving apparatus for giving freedom of movement to those patients who require an auxiliary artificial heart. Various safety devices are provided to avoid danger due to erroneous running of the wheelchair at the time when the patients board on or alight from the wheelchair and after alighting therefrom. For the purpose of enlarging a sphere of movement of the patients and preventing possible dangers, a motor-operated tube taking-up mechanism is provided and the wheelchair is permitted to run only when the tubes are in the orderly housed condition. A pressure compensating solenoid valve is provided in parallel to a pressure adjusting solenoid valve and a tank is dispensed with so as to make reduction in size of the artificial heart driving apparatus.

Description

The solid state relay SSR9 for controlling the solenoid valve 135 is turned when the output level of TM1 is L and the output level of TM2 is H, i.e., only in a period of T3=(T2-T3). The solid state relay SSR9 for controlling the solenoid valve 135 is turned on when the output level of TM1 is L and the output level of TM2 is H, i.e., only in a period of T3=(T2-T1). Timing of T3 is within the period where the SSR5 is turned OFF, i.e., the solenoid valve 132 is closed, so that the higher pressure from the compressor 71 will never be directly applied to the artificial heart. Although the pressure at the output terminal of the solenoid valve 131 becomes somewhat higher than the set pressure after opening of the solenoid valve 135, the pressure on the artificial heart side will never become higher than the set pressure because the output terminal pressure of the solenoid 131 is lowered below the predetermined pressure immediately after subsequent opening of the solenoid valve 132. In this embodiment, there is provided to accumulator there is not provided an accumulator at the pressure output terminals of the pressure adjusting valves 131, 137, 133 and 139. As an alternative, the solenoid valves 135, 141, 136 and 142 are opened at a predetermined timing during the closed period of the solenoid valves 132, 138, 134 and 140, respectively, whereby the pressure waveform having the sharp rising as shown in FIG. 12c appears in the artificial heart. If the pressure compensating solenoid valves 135, 141, 136 and 142 are not opened, the rising of the pressure waveform will be delayed as seen from a one-dot chain line. Although the pressure compensating solenoid valves are provided in both positive and negative system in the illustrated embodiment, it is found that the satisfactory result can be attained in practice even in case where those solenoid valves are provided in the positive pressure system only.

The microcomputer units CPU1 and CPU2 used in this embodiment are of single board microcomputer units H62SCO1 manufactured by Hitachi Ltd. The summary configuration of H62SCO1 is shown in FIG. 13. Refering to FIG. 13, each unit comprises a microprocessor 6802, I/O ports, timer, RAM, ROM, etc.

FIG. 14 shows the configuration of the control board 600. Referring now to FIG. 14, switches SW1, SW2, SW3, SW4, SW5, SW6, SW7 and SW8 serve to issue instructions for pressure setting and are switches for instructing lefthand positive pressure up, lefthand positive pressure down, lefthand negative pressure up, lefthand negative pressure down, righthand positive pressure up, righthand positive pressure down, righthand negative pressure up and righthand negative pressure down, respectively. Switches SW9, SW10, SW11 and SW12 serve to set the duty ratio of the positive pressure to the negative pressure applied to the artificial heart, and are switches for instructing lefthand duty ratio up, lefthand duty ratio down, righthand duty ratio up and righthand duty ratio down, respectively. Designated at SW13 and SW14 are switches for instructing up and down in heart rate, respectively.

FIG. 15 shows the details of the wheelchair driving motor control unit 75 in FIG. 10. Referring now to FIG. 15, the wheelchair driving motors M1 and M2 are connected to independent driving circuits MD1 and MD2, respectively. The driving circuits MD1 and MD2 are each of a H-type driving circuit and, when either one of switching elements locating on a diagonal line, electrical current is caused to flow into an armature of the motor in a predetermined direction so as to rotate it in a predetermined direction.

The contact of a relay RL1 is connected in parallel to an armature of the motor M1. This contact is a normally closed type. Thus, the contact is opened when the relay RL1 is in the ON state, but closed when it is turned OFF to effect the dynamic brake. The motor M2 also includes a similar brake circuit.

Both motor driving circuits MD1 and MD2 are controlled by a microcomputer CPU3. The motor driving circuit MD1 is connected to output ports 01, 02 and 03 of the CPU3 through a buffer BF3, while the motor driving circuit MD2 is connected to output ports 04, 05 and 06 of the CPU3 through a buffer BF3. Power source Vcc for the microcomputer CPU3 is supplied from a stabilized power supply circuit RPS. A battery of 24 V is connected to an input terminal of the stabilized power supply circuit RPS through a relay RL3. The relay RL3 is controlled by the system control unit 200.

Sliders of two potentiometers 121 and 122 connected to the control lever 58 are connected to first and second channels CH1 and CH2 of an analog/digital converter AD2, respectively, and output terminals D0 through D7 of the AD2 are connected to input ports of the microcomputer CPU3. The predetermined constnat voltage is applied to both potentiometers 121 and 122 from the stabilized power supply circuit RPS.

FIG. 16 shows the detail configuration of the system control unit 200 in FIG. 10. Referring now to FIG. 16, the system control unit 200 is controlled by a microcomputer CPU4. To input ports of the CPU4 are connected various switches SW1L, SW1R, SW3L, SW3R, SW4 and 102 through a buffer BF4.

The reel taking-up instruction switch SW2 is connected to a pulse motor driver PMD and a solenoid driver SD1 through the buffer BF4. The PMD drives a reel taking-up motor M3, while the SD1 drives a solenoid SL3 of the electromagnetic actuator 97. A circuit comprising solid state relays SSR13, SSR17, etc. connected to an output port of the CPU4 serves to drive the power supply relay RL3 shown in FIG. 15. Solid state relays SSR14 and SSR15 connected to output ports of the CPU4 serve to energize solenoids of the electromagnetic actuators 114 for locking the left and right armrests.

Designated at BZ is a warning buzzer. LE1 and LE2 denote light emitting diodes for indicating an alarm in the artificial heart system and provided in the alarm display 59 shown in FIG. 2a. LE3 and LE4 denote light emitting diodes for indicating an alarm in the wheelchair system and are provided in the alarm display 60. The light emitting diodes LE1 and LE4 emit a red color light, while the diodes LE2 and LE4 emit a green color light.

A solid state relay SSR16 connected to an output port of the CPU4 makes the ON/OFF control of power source for the monitor television TV. A switch SW5 is a manual switch for turning ON/OFF the monitor television TV. Designated at IF1, IF2, IF3 and IF4 are interface circuits for transmitting signals to other circuits. The IF1 and IF2 are connected to the CPU1, while the IF3 and IF4 are connected to the CPU3. Those interface circuits IF1, IF2, IF3 and IF4 are each composed of an inverter, photo coupler PC1, etc.

FIGS. 17a, 17b and 17c show summary operation of the microcomputer CPU3 in FIG. 15, and FIG. 17d shows one example of the operating timing. FIG. 17a denotes a main routine, FIG. 17b denotes a voltage sampling subroutine and FIG. 17c denotes an interrupt processing routine.

The summary operation thereof will be now described. In this embodiment, to make small loss of the power, both direct current motors M1 and M2 are subjected to the switching control and a pulse width of the switching pulses is modulated in accordance with the positions of the potentiometers 121 and 122 connected to the control lever 58, thereby to set a motor speed.

When positive pulses are applied to the output ports of the CPU3, both motors M1 and M2 are driven forwards, and when positive pulses are applied to the output ports 03 and 06 thereof, both motors M1 and M2 are driven backwards. In this embodiment, the wheelchair moves forwards when both M1 and M2 are driven forwards at the same speed, moves rearwards when both are driven backwards at the same speed, and curves or turns forwards or rearwards in cases other than the aboves. When both motors M1 and M2 are not driven, the relays RL1, etc. are turned OFF and the armatures of the motors M1 and M2 are short-circuited to effect the brake.

By referring to FIGS. 17a, 17b, 17c and 17d, the operation of the CPU3 will be now described in order. First, when the power supply is turned ON, i.e., when the relay RL3 shown in FIG. 15 is turned ON, the CPU3 set the individual output ports at their levels, clears the content of the random access memory (RAM) and stores initial parameters having been previously stored in the read-only memory (ROM) into registers (memories) allocated to the individual parameters. In the initial state, the output ports 01 and 04 of the CPU3 are set at L, thus coming into the braking mode. Also, interrupt is inhibited in this state.

When the CPU is set interruptible, the timer issues an interrupt demand for each predetermined period of time. If interrupt is effected, the CPU3 executes the processing as shown in FIG. 17c. This proccessing will be described later in detail.

Then, the CPU3 reads the slider potentials of the potentiometers 121 and 122 connected to the running control lever 58. The detailed of this sampling processing is shown in FIG. 17b. As a result of the sampling, when the present potential is different from the previously sampled value, i.e., when the control lever 58 has been moved, the CPU5 updates the speed instruction data for the motors and then operates as follows.

By comparing the speed instruction data with predetermined values, it is judged whether driving or braking. More specifically, in the illustrated embodiment the constant voltage of 12 V is applied to one ends of the potentiometers 121 and 122, and the slider potential assumes about 6 V when the control lever 58 is in its neutral position (stoppage position). Therefore, since a range of about 6±0.2 V is assumed as a stoppage region, it is arranged that the speed instruction data is compared with the data representing the upper and lower limits of that stoppage region (i.e. predetermined values). The voltage higher than the values corresponding to the stoppage region represents the forward driving, while the voltage lower than those values represent the backward driving.

When the speed instruction data is at a stoppage level (i.e., below the predetermined values), interrupt is inhibited, a low level L is set to the output ports 02, 03, 05 and 06 to inhibit driving of the motors, and a low level L is set to the output ports 01 and 04, thus setting the braking mode and setting the braking flag to "1".

On the other hand, when the speed instruction data is at a driving level (i.e., above the predetermined values), widths (time period) LD and RD of pulses for driving the motors M1 and M2 are calculated based on the speed instruction data. If the braking flag is set to "1", the braking mode is released as follows. More specifically, the value of the counter COT is cleared to 0, the output ports 01 and 04 are set to H (the relay RL1 ON) and the braking flag is cleared to "0" so as to allow the interrupt demand.

The voltage sampling processing (FIG. 17b) will be now described. First, the input channel designation for the A/D converter AD2 is set to CH1 (output voltage of the potentiometer 121), the A/D conversion start instruction (TRIG) is issued and then it waits for the end A/D conversion (EOC), i.e., until EOC will be output. Upon the end of conversion, the converted data is read and stored in the predetermined register. Subsequently, the input channel designation is set to CH2 (output voltage of 122), the A/D conversion start instruction is issued and then it waits for the end of A/D conversion. Upon the end of conversion, the converted data is read and stored in the predetermined register.

The interrupt processing of FIG. 17c will be now described by referring to the operating timing of FIG. 17d. The counter COT serves to count a time and, more concretely, is formed of an N-notation counter which counts as follows; 0, 1, 2, . . . N--1, N, 0, 1 . . . , which is counted up one by one every when the interrupt processing is executed. The time corresponding to the value N represents one period of the motor driving pulses.

When the value of the counter COT becomes 0, the output port determined in accordance with the driving directions of the motors is set to a high level H. In other words, in case of the lefthand motor M1, the output port 02 is set to H for its forward rotation and the output port 03 is set to H for its backward rotation. In case of the righthand motor M2, the output ports 05 or 06 is set to H for its forward or backward rotation, respectively. The pulses for driving the M1 and those for driving the M2 have the same timing.

When the value of the counter COT equals to the lefthand motor energizing pulse width LD, both output ports 02 and 03 are set to L, and when the value of the counter COT equals to the righthand motor energization pulse width RD, both output ports 05 and 06 are set to L.

Therefore, the pulses for energizing the motor M1 are set to H during the time the value of the COT assumes 0 through LD, and are set to L (i.e., M1 is deenergized) during the time except for the above. The pulses for energizing the motor M2 are set to H during the time the value of the COT assumes 0 through RD, and are set to L during the time except for the above. Since both motors M1 and M2 are rotated at a speed in accordance with the power applied thereto, namely, the duty ratio of the time period for energization to that for deenergization, the motor speed can be varied by changing the values of LD and RD.

FIGS. 18a and 18b show summary operation of the microcomputer CPU1 in FIG. 12a. FIG. 18a denotes a main routine and FIG. 18b denotes an interrupt processing routine. The description will be now made by referring to FIGS. 18a and 18b.

First, when the power supply is turned ON, the individual output ports are set at their initial levels, the content of the random access memory (RAM) is cleared and the data having been previously stored in the read-only memory (ROM) is read out therefrom to set the initial values to the parameters. The parameters for the CPU1 are a righthand positive pressure target value P1, righthand negative pressure target value P2, lefthand positive pressure target value P3, lefthand negative pressure target value P4, etc. In this embodiment, the initial values of those pressures P1, P2, P3 and P4 are set at +30, -30, +100 and -50 (mmHg), respectively.

After the above processing, interrupt becomes allowable. In this embodiment, interrupts are periodically occurred by the internal timer at a period of 4 msec. After it waits for the interrupt demand, sampling of the pressure data is performed. This sampling processing is similar to that shown in FIG. 17b. The difference are in that there are four parameters to be sampled, outputs RPP, RNP, LPP and LNP from the four pressure sensors, and that since the bit number of the data is 12 bits, the read processing is performed two times for each sampling.

The sampled pressure data is checked to judge the presence or absence of anomaly data. In other words, when the detected pressure is abnormally different from the target value, this is regarded as anomaly. It is to be noted that, in this embodiment, the pressure compensating solenoid valves 135, 141, 136 and 142 are provided, thus resulting in a possibility the pressure becomes relatively so large temporarily, but this possibility is masked by making sampling several times and then averaging the plural pressure data thus sampled.

Should there occur any anomaly, the anomaly data is converted to the numeral code data. Then, the anomaly display data indicating that numeral code data and the part where the anomaly has occurred, is output to the display control unit 500 so as to display them on the monitor television TV. Also, the anomaly occurrence code data is transferred in the form of serial data to the microcomputer CPU4 in the system control unit.

If there is no anomaly, the last m pressure data having been stored in the random access memory are averaged. The averaged data is converted to the numeral code, which is sent to the display control unit 500. When the microcomputer CPU4 in the system control unit is transmitting data, the data is received and this received data is also sent to the display control unit 500. With the control board 600 being connected, the states of keys are read. If there is any key-in operation, the value of the righthand positive target pressure P1, righthand negative target pressure P2, lefthand positive target pressure P3 or the lefthand negative target pressure P4 is updated stepwisely by a predetermined amount for each time in accordance with the key operated. Incidentally, since the upper and lower limit is preset, it is impossible to make pressure setting out of such a limit range.

The interrupt processing shown in FIG. 18b will be now described. First, the positive pressure RPP in the righthand artificial heart driving system is checked. When it is lower than the predetermined pressure P1, the pressure adjusting valve 131 is set open, and in the case except for the above, the valve 131 is set closed. Subsequently, the negative pressure RNP in the righthand artificial heart driving system is checked. When the (absolute) value of RNP is lower than P2, the pressure adjusting valve 133 is set open, and if not so, the valve 133 is set closed. Next, the positive pressure LPP and the negative pressure LNP in the lefthand artificial heart driving system are compared with P3 and P4, respectively, and the pressure adjusting valve 137 or 139 is set open or closed. Differently stated, it is so arranged in this embodiment that the pressure adjusting valve is opened only when the detected pressure (absolute value) is lower than the target pressure.

Summary operation of the microcomputer CPU2 in FIG. 12b is shown in FIGS. 19a and 19b. FIG. 19a denotes a main routine and FIG. 19b denotes an interrupt processing routine. The description will be now made by referring to FIGS. 19a and 19b.

First, when the power supply is turned ON, the microcomputer CPU2 sets the output ports at their initial levels, clears the content of the random access memory (RAM) and reads out the values having been previously stored in the read-only memory (ROM) to set the parameters at their initial values.

The parameters for the CPU2 are a heart rate PR, duty of the lefthand artificial heart DL, duty of the righthand artificial heart DR, etc. In this embodiment, the initial values of those parameters PR, DL and DR are set at 100 rpm, 45% (duration time 270 ms) and 55% (duration time 330 ms), respectively.

Subsequently, the CPU2 executes the processing loop including such processings as interrupt waiting, check of a key input from the control board, parameter display, etc. If there occurs any key input, the kind of the input key is judged, comparison of the desired value of the parameter to be changed with the upper and lower limit values as well as calculation thereof is performed, and arithmetic processing of those parameters in association with the changed parameter is carried out. These processings are progressed under execution of the related various subroutines.

The interrupt processing will be now described. The value of both counters COR and COL are each counted up for each interrupt processing. When the counted value reaches PR (parameter of time determined by the heart rate), it is cleared to "0". When the value of the counter COR becomes 0, the valves 132 and 134 are set open and closed (positive pressure applying mode), respectively. When the value of the counter COR becomes equal to the value DR of the duty parameter, the valves 132 and 134 are set closed and open (negative pressure applying mode), respectively. After the above processing, the counter COR is counted up.

Likewise, when the value of the counter COL becomes 0, the valves 138 and 140 are set open and closed (positive pressure applying mode), respectively, and when the value of the counter COL beocmes equal to the value DL of the duty parameter, the valves 138 and 140 are set closed and open (negative pressure applying mode), respectively.

Summary operation of the microcomputer CPU4 in FIG. 16 is shown in FIG. 20. Referring now to FIG. 20, when the power supply is turned ON, the output ports are set at their initial levels, the content of the random access memory (RAM) is cleared, and the apparatus is set in the initial state in accordance with the program data stored in the read-only memory. This causes the light emitting diodes LE1 and LE3 to be set into deenergization and the light emitting diodes LE2 and LE4 to be set into energization, whereby green color (normal state) is indicated on both anomaly displays 59 and 60 of the wheelchair.

Thereafter, the CPU4 periodically checks the states of various switches and then operates in accordance with the checked states. When the armrest unlocking switches SW1L and SW1R are turned ON, the solenoids SL1 and SL2 of the electromagnetic actuators 114 and set into energization, and when those switches are turned OFF, the solenoids SL1 and SL2 are set into deenergization. Since energization of the solenoid SL1 or SL2 releases the armrest from its locked state, the lefthand or righthand armrest becomes rotatable in a range of 90 degrees. On the other hand, when the armrest is set in the running position with the solenoid being deenergized, it is locked.

Next, the CPU4 checks the states of the lefthand armrest position detecting switch SW3L, righthand armrest position detecting switch SW3R, artificial heart driving tube position detecting switch 102 and the running control lever presence/absence detecting switch SW4.

When the lefthand and righthand armrests 52L and 52R are in the running positions (both SW3L and SW4R ON), the artificial heart driving tubes 57L and 57R are both in the housed condition (102 ON) and the running control lever 58 is fitted in the predetermined position (SW4 ON), it is assumed that the user sits on the wheelchair and wishes to run. Thus, the relay RL3 is turned ON to set ON the power for the wheelchair driving motor control unit 75. At the same time, the data for displaying that the apparatus is in the ready state, is sent to the CPU1 through the interface circuit IF1. The CPU1 transfers the received data to the display control unit.

When the lefthand armrest is in the unlocked position, the righthand armrest is in the unlocked position, the artificial heart driving tubes are in the drawn-out condition, or the running control lever is absent, the relay RL3 is turned OFF to set OFF the power for the wheelchair driving motor control unit 75. As a result, the output ports 01, 02, 03, 04, 05 and 06 of the CPU3 assume a low level L and both motors M1 and M2 are not supplied with the power from the outside, so that operation of the wheelchair is inhibited. At the same time, since the relay RL1 is turned OFF and the contact of RL1 is closed, the armatures of both motors M1 and M2 are short-circuited and the dynamic braking mode is set.

Subsequently, the data for displaying the operating instruction such as "Please set the running control lever", etc. is sent to the CPU1 so as to display it on the monitor television TV. Also, the light emitting diode LE3 is lit up and the LE4 is put out, thereby to indicate red color on the anomaly display 60 for the wheelchair system.

When receiving the data sent from the CPU1, the CPU3 undergoes interrupt and executes the interrupt processing. In this interrupt processing, the CPU3 receives the data through the interface circuit IF2 and sets the receipt flag to "1" upon the completion of receipt. When the receipt flag becomes "1", the received data is judged by the main routine. In the event the anomaly code has been sent, the anomaly processing operation will be performed as follows.

That is, the light emitting diode LE1 is lit up and the LE2 is put out so as to indicate red color (occurrence of anomaly) on the artificial anomaly display 59. At the same time, the warning buzzer BZ is buzzed, the power for the monitor television TV is set ON (SSR16 ON) and the receipt flag is cleared to "0".

Having now fully set forth both structure and operation of preferred embodiment of the concept underlying the present invention, various other embodiments as well as certain variations and modifications of the embodiment herein shown and described will obviously occur to those skilled in the art upon becoming familiar with the underlying concept. It is to be understood, therefore, that with the scope of the appended claims, the invention may be practiced otherwise than as specifically set force herein.

Claims

1. A mobile apparatus for transporting a patient connected to a medical appliance comprising:

a wheelchair;

medical appliance driving means mounted on said wheelchair and comprising; a positive pressure source; a first solenoid valve having an input terminal connected to an output terminal of said positive pressure source; first pressure detecting means for detecting the pressure at an output terminal of said first solenoid valve; a second solenoid valve having an input terminal connected to the output terminal of said first solenoid valve and an output terminal adapted to be connected to said medical appliance; a negative pressure source; a third solenoid valve having an input terminal connected to said negative pressure source; second pressure detecting means for detecting the pressure at an output terminal of said third solenoid valve; a fourth solenoid valve having an input terminal connected to the output terminal of said third solenoid valve and an output terminal adapted to be connected to said medical appliance; and first electronic control means adapted to control opening and closing of said first solenoid valve in response to an output signal from said first pressure detecting means, control opening and closing of said third solenoid valve in response to an output signal from said second pressure detecting means, and to control opening and closing of said second and fourth solenoid valves at predetermined timings, respectively;

electric motor means for driving said wheelchair;

instruction means for controlling energization of said electric motor means;

state detecting means for detecting at least one state of at least one part moveable on said wheel chair, the state of a moveable part of said medical appliance driving means and the state of said instruction means and providing signals indicative of said states; and

second electronic control means connected to said state detecting means for energizing said electric motor means in response to operation of said instruction means, and for inhibiting energization of said electric motor means when said state detecting means detects a dangerous state.

2. An apparatus according to claim 1, wherein said instruction means comprises a control lever and a lever supporting means for supporting said lever in a detachable manner, and said state detecting means provides a signal indicative of the state of attachment of said control lever with respect to said lever supporting means.

3. An apparatus for driving a medical appliance according to claim 1, wherein said wheelchair comprises at least one armrest moveable on said wheelchair and lock means for locking said armrest in a predetermined position, and said state detecting means provides a signal indicative of the state of said lock means.

4. An apparatus for driving a medical appliance according to claim 3, wherein said armrest is constructed to be moveable horizontally about a support shaft, and said lock means includes engagement means engaged with said support shaft and an electromagnetic actuator for moving said engagement means out of engagement with said shaft.

5. An apparatus for driving a medical appliance according to claim 1, wherein said medical appliance driving means comprises; flexible tubes connected at one end to said second solenoid valve and said fourth solenoid valve respectively and adapted to be connected at the other ends thereof to said medical appliance; and tube taking-up means for retracting said flexible tubes and wherein said state detecting means provides a signal indicative of the state of retraction of said flexible tubes.

6. An apparatus for driving a medical appliance according to claim 5, wherein said tube taking-up means comprises; a first fixed member having a first bore axially penetrating through the central part thereof and a groove in a position of the outer periphery thereof; a second fixed member having first and second passages formed at positions opposite to said groove of said first fixed member, and fitted to said outer periphery of said first fixed member; a moveable member provided with a third passage formed at a position opposite to said first bore and with a fourth passage formed at a position opposite to said second passage, and fitted to the outer periphery of said second fixed member rotatably relative to the same; and a tube reel rotatable together with said moveable member, the pressure output terminals of said second and fourth solenoid valves being connected to at least one of said first bore and said first passage, and said flexible tubes being connected to at least one of said third and fourth passages.

7. An apparatus for driving a medical appliance according to claim 5, wherein said tube taking-up means includes electric motor means for rotating said tube reel and switch means for controlling energization of said motor.

8. An apparatus for driving a medical appliance according to claim 1, wherein, when energization of said electric motor is inhibited, said second electronic control means short circuits an armature of said electric motor means for braking movement of said wheelchair.

9. An apparatus for driving a medical appliance according to claim 1, wherein said medical appliance driving means includes a fifth solenoid valve connected in parallel to said first solenoid valve connected in parallel to said third solenoid valve and a sixth solenoid valve, and said first electronic control means controls opening and closing or said fifth and sixth solenoid valves according to predetermined timing in synchronous relation with operation of said second and fourth solenoid valve.

10. An apparatus for driving a medical appliance according to claim 9, wherein said first electronic control means comprises means for setting said fifth solenoid valve in the opened state according to a predetermined timing during the time said second solenoid is closed, and means for setting said sixth solenoid valve in the opened state according to a predetermined timing during the time said fourth solenoid valve is closed.

11. An apparatus for driving a medical appliance according to claim 10, wherein said first electronic control means comprises means for setting said fifth solenoid valve in the opened state for a predetermined time shorter than the closing time of said second solenoid valve after the lapse of a predetermined time from closing of said second solenoid valve, and means for setting said sixth solenoid valve in the opened state for a predetermined time shorter than the closing time of said fourth solenoid valve after the lapse of a predetermined time from closing of said fourth solenoid valve.

12. A mobile apparatus for transporting a patient connected to a medical appliance comprising:

a wheelchair;

medical appliance driving means mounted on said wheelchair and comprising; a positive pressure source; a first solenoid valve having an input terminal connected to an output terminal of said positive pressure source; first pressure detecting means for detecting the pressure at an output terminal of said first solenoid valve; a second solenoid valve having an input terminal connected to the output terminal of said first solenoid valve and an output terminal adapted to be connected to said medical appliance through a flexible tube; a negative pressure source; a third solenoid valve having an input terminal connected to said negative pressure source; a fourth solenoid valve having an input terminal connected to an output terminal of said third solenoid valve and an output terminal adapted to be connected to said medical appliance through a flexible tube; and first electronic control means adapted to control opening and closing of said first solenoid valve in response to an output signal from said first pressure detecting means, control opening and closing of said third solenoid valve in response to an output signal from said second pressure detecting means, and to control opening and closing of said second and fourth solenoid valve at predetermined times, respectively;

electric motor means for driving said wheelchair;

instruction means for controlling energization of said electric motor means;

first state detecting means for detecting the state of at least one part moveable on said wheelchair;

second state detecting means for detecting the state of said flexible tube of said medical appliance driving means;

third state detecting means for detecting the state of said instruction means; and

second electronic control means connected to said state detecting means for energizing said electric motor in response to operation of said instruction means, and for inhibiting energization of said electric motor when at least one of said first, second and third state detecting means detects a dangerous state.

13. An apparatus for driving a medical appliance according to claim 12, wherein said instruction means comprises a control lever and a lever supporting means for supporting said lever in a detachable manner, and said third state detecting means provides a signal indicative of the state of attachment of said control lever to said lever supporting means.

14. An apparatus for driving a medical appliance according to claim 12, wherein said wheelchair comprises at least one armrest moveable on said wheelchair and lock means for locking said armrest in a predetermined position, and said first state detecting means provides a signal indicative of the state of said lock means.

15. An apparatus for driving a medical appliance according claim 14, wherein said armrest is constructed to be moveable horizontally about a support shaft, and said lock means includes engagement means engaged with said support shaft and an electromagnetic actuator for moving said engagement means out of engagement with said shaft.

16. An apparatus for driving a medical appliance according to claim 12, wherein said medical appliance driving means comprises tube taking-up means for rolling up said flexible tubes, and said second state detecting means generates a signal in accordance with the rolled-up condition of said flexible tubes.

17. An apparatus for driving a medical appliance according to claim 16, wherein said tube taking-up means comprises; a first fixed member having a first bore axially penetrating through the central part thereof and a groove in a portion of the outer periphery thereof; a second fixed member having a first and second passage formed at positions opposite to said groove of said first fixed member, and fitted to said outer periphery of said first fixed member; a moveable member provided with a third passage formed at a position opposite to said first bore and with a fourth passage formed at a position opposite to said second passage, and fitted to the outer periphery of said second fixed member rotatably relative to the same; and a tube reel rotatable together with said moveable member, the pressure output terminals of said second and fourth solenoid valves being connected to at least one of said first bore and said first passage, and said flexible tubes being connected to at least one of said third and fourth passages.

18. An apparatus for driving a medical appliance according to claim 16, wherein said tube taking-up means includes electric motor means for rotating said tube reel and switch means for controlling energization of said motor.

19. An apparatus for driving a medical appliance according to claim 12 wherein said medical appliance driving means comprises tube taking-up means for rolling up said flexible tubes, and said second state detecting means generates a signal in accordance with the rolled-up condition of said flexible tubes.

20. A mobile apparatus for transporting a patient connected to a medical appliance comprising:

a wheelchair;

medical appliance driving means mounted on said wheelchair and comprising; a positive pressure source; a first solenoid valve having an input terminal connected to an output terminal of said positive pressure source; first pressure detecting means for detecting the pressure at an output terminal of said first solenoid valve; a second solenoid valve having an input terminal connected to the output terminal of said first solenoid valve and an output terminal adapted to be connected to said medical appliance through a flexible tube, a negative pressure source; a third solenoid valve having an input terminal connected to said negative pressure source; a fourth solenoid valve having an input terminal connected to an output terminal of said third solenoid valve and an output terminal adapted to be connected to said medical appliance through a flexible tube; and first electronic control means adapted to control opening and closing of said first solenoid valve in response to an output signal from said first pressure detecting means, control opening and closing of said third solenoid valve in response to an output signal from said second pressure detecting means, and to control opening and closing of said second and fourth solenoid valves at predetermined timings, respectively; and a tube taking-up means for rolling up said flexible tubes;

electric motor means for rotating said wheelchair;

instruction means for controlling energization of said electric motor means;

first state detecting means for detecting the state of at least one part moveable on said wheelchair;

second state detecting means for detecting the rolled up state of said flexible tubes of said medical appliance driving means;

third state detecting means for detecting the state of said instruction means; and

second electronic control means connected to said state detecting means for energizing said electric motor in response to operation of said instruction means, and for inhibiting energization of said electric motor when at least one of said first, second and third state detecting means detects a dangerous state.

21. A mobile apparatus for transporting a patient connected to a medical appliance comprising:

a wheelchair;

medical appliance driving means mounted on said wheelchair and comprising; a positive pressure source; a first solenoid valve having an input terminal connected to an output terminal of said positive pressure source; first pressure detecting means for detecting the pressure at an output terminal of said first solenoid valve; a second solenoid valve having an input terminal connected to the output terminal of said first solenoid valve and an output terminal adapted to be connected to said medical appliance through a flexible tube; a negative pressure source; a third solenoid valve having an input terminal connected to said negative pressure source; a fourth solenoid valve having an iput terminal connected to an output terminal of said third solenoid valve and an output terminal adapted to be connected to said medical appliance through a flexible tube; a fifth solenoid valve connected in parallel to said first solenoid valve and a sixth solenoid valve connected in parallel to said third solenoid valve; and first electronic control means adapted to control opening and closing of said first solenoid valve in response to an output signal from said first pressure detecting means, control opening and closing of said third solenoid valve in response to an output signal from said second pressure detecting means, control opening and closing of said second and fourth solenoid valves at predetermined timings, respectively, and to control said fifth and sixth solenoid valves at the predetermined timing in synchronous relation with operation of said second and fourth solenoid valve;

electric motor means for driving said wheelchair;

instruction means for instructing energization of said electric motor;

first state detecting means for detecting the state of at least one part moveable on said wheelchair;

second state detecting means for detecting the state of said flexible tube of said medical appliance driving means;

third state detecting means for detecting the state of said running instruction means; and

second electronic control means connected to said state detecting means for energizing said electric motor in response to operation of said instruction means, and for inhibiting energization of said electric motor means when at least one of said first, second and third state detecting means detects a dangerous state.

22. An apparatus for driving a medical appliance comprising:

a positive pressure source;

a first solenoid valve having an input terminal connected to an output terminal of said positive pressure source;

a first pressure detecting means for detecting the pressure at an output terminal of said first solenoid valve;

a second solenoid valve having an input terminal connected to the output terminal of said first solenoid valve and an output terminal adapted to be connected to said medical appliance;

a negative pressure source;

a third solenoid valve having an input terminal connected to an output terminal of said negative pressure source;

a second pressure detecting means for detecting the pressure at an output terminal of said third solenoid valve;

a fourth solenoid valve having an input terminal connected to the output terminal of said third solenoid valve and an output terminal adapted to be connected to said medical appliance;

a fifth solenoid valve having an input terminal connected to said positive pressure source and an output terminal connected to the output terminal of said first solenoid valve; and

first electronic control means adapted to control opening and closing of said first solenoid valve in response to an output signal from said first pressure detecting means, control opening and closing of said third solenoid valve in response to an output signal from said second pressure detecting means, control opening and closing of said second and fourth solenoid valves at predetermined timings, respectively, and to control opening and closing of said fifth solenoid valve according to predetermined timing in synchronous relation with operation of said second solenoid valve.

23. An apparatus for driving a medical appliance according to claim 22, wherein said apparatus includes a sixth solenoid valve having an input terminal connected to said negative pressure source and an output terminal connected to the output terminal of said third solenoid valve and said medical appliance; and said first electronic control means controls opening and closing of said sixth solenoid valve according to predetermined timing in synchronous relation with operation of said fourth solenoid valve. 24. An apparatus for driving a medical appliance according to claim 23, wherein said first electronic control means comprises means for setting said fifth solenoid valve in the opened state according to a predetermined timing during the time said second solenoid is closed, and means for setting said sixth solenoid valve in the opened state according to a predetermined timing during the time said fourth solenoid valve is closed. 25. An apparatus for driving a medical appliance according to claim 24, wherein said first electronic control means comprises means for setting said fifth solenoid valve in the opened state for a predetermined time shorter than the closing time of said second solenoid valve after the lapse of a predetermined time from closing of said second solenoid valve, and means for setting said sixth solenoid valve in the opened state for a predetermined time shorter than the closing time of said fourth solenoid valve after the lapse of a predetermined time from closing of said fourth solenoid valve. 26. A driving method for a medical appliance which is driven by applying to a driving portion of a medical appliance positive and negative pressures alternatively from a positive pressure source connected through a positive pressure adjusting valve and s negative pressure source connected through a negative pressure adjusting valve, wherein when the positive pressure is applied to said driving portion, compensating pressure for pressure drop in said driving portion is applied to said driving portion of said medical appliance through circuit means parallel to said positive pressure adjusting valve in synchronous relation therewith and when the negative pressure is applied to said driving portion, compensating pressure for pressure rise in said driving portion is applied to said driving portion of said medical appliance through circuit means parallel to said negative pressure adjusting valve in synchronous relation therewith. 27. An apparatus for driving a medical appliance comprising:

a positive pressure source;

a positive pressure adjusting valve means connected to said positive pressure source for adjusting the pressure from said positive pressure source to a predetermined positive pressure;

a negative pressure source;

a negative pressure adjusting valve means connected to said negative pressure source for adjusting the pressure from said negative pressure source to a predetermined negative pressure;

a pressure changing valve means for applying said predetermined positive and negative pressure alternately to said medical appliance; and

a positive pressure branch having an inlet between said positive pressure source and said positive pressure adjusting valve means and an outlet between said positive pressure adjusting valve means and said pressure changing valve means for applying a pressure higher than that from the positive pressure adjusting valve means when the latter is being applied to said medical appliance; and

a negative pressure branch having an inlet between said negative pressure source and negative pressure adjusting valve means and an outlet between said negative pressure adjusting valve means and said pressure changing valve means for applying a pressure lower than that from the negative pressure adjusting valve means when the latter is applied upon said

medical appliance. 28. A driving method for a medical appliance which is driven by applying to a driving portion of a medical appliance positive and negative pressures alternatively from a positive pressure source connected through a positive pressure adjusting valve and a negative pressure source connected through a negative pressure adjusting valve, wherein when the positive pressure is applied to said driving portion, compensating pressure for pressure drop in said driving portion is applied to said driving portion of said medical appliance in synchronous relation with said positive pressure adjusting valve and when the negative pressure is applied to said driving portion, compensating pressure for pressure rise in said driving portion is applied to said driving portion of said medical appliance in synchronous relation with

said negative pressure adjusting valve. 29. An apparatus for driving a medical appliance comprising:

a positive pressure source;

a positive pressure adjusting valve means connected to said positive pressure source for adjusting the pressure from said positive pressure source to a predetermined positive pressure;

a negative pressure source;

a negative pressure adjusting valve means connected to said negative pressure source for adjusting the pressure from the negative pressure source to a predetermined negative pressure;

a pressure changing valve means for applying said predetermined positive and negative pressure alternately to said medical appliance;

positive pressure compensating means including control valve means having an outlet connected between said positive pressure adjusting valve means and said medical appliance; and

negative pressure compensating means including control valve means having an outlet connected between said negative pressure adjusting valve means and said medical appliance.