Electronic circuit for a dynamic pressure wave pneumatic control system

• US 4,419,988 A
• Filed: 08/03/1981
• Issued: 12/13/1983
• Est. Priority Date: 08/03/1981
• Status: Expired due to Fees

• Current Assignee: Jobst Institute Incorporated
• Original Assignee: Jobst Institute Incorporated
• Inventors: Mummert, Thomas A.
• Primary Examiner(s): Howell, Kyle L.
• Assistant Examiner(s): Fukushima, Christine A.
• Application Number:
  US06/289,267
• Time in Patent Office: 862 Days
• Field of Search: 128/1 R, 128/24 R, 128/30, 128/30.2, 128/204.21, 128/204.23, 128/299
• US Class Current: 601/152
• CPC Class Codes: A61H 2201/5074 using electric pressure transducers with proportional output
• CPC Class Codes: A61H 9/0078 with intermittent or alternately inflated bladders or cuffs mattresses for preventing bed-sores with alternated pressurized chambers A61G7/05776

Abstract

The electronic circuit includes switch means responsive to the pressure within a first chamber of a dynamic pressure wave appliance for generating an enabling signal when a predetermined pressure level in the first chamber has been reached. A transducer is provided to generate a signal representative of the pressure within a second chamber of the appliance. The electronic circuit includes means for generating a signal representing a first predetermined pressure level and a second predetermined pressure level in the second chamber when the enabling signal is generated. A comparator is responsive to the predetermined pressure level signals and the transducer signal for generating control signals to a solenoid. The solenoid is connected to appropriate valves for regulating the pneumatic control circuit. The electronic control circuit will cause a dynamic pressure wave appliance to apply a pressure to a human or animal extremity which begins at the most distant end and travels up the extremity in the nature of a pressure wave.

Claims

1. In an apparatus intended for use in applying compressive pressure to a mammal extremity including a first inflatable chamber, a second inflatable chamber, and pneumatic control means responsive to control signals and pneumatically connected to the first and second chambers for inflating and deflating the chambers from a source of pressurized gas such that the chambers apply compressive pressure to the extremity, an electronic circuit for regulating a pneumatic control means comprising:

means responsive to the pressure within a first chamber for generating an enabling signal when a first predetermined pressure level has been reached;

means connected to said pressure responsive means and responsive to the absence of said enabling signal for generating a first control signal to the pneumatic control means to connect a source of pressurized gas to the first chamber, and responsive to the presence of said enabling signal for generating a second control signal to disconnect the first chamber from the source of pressurized gas and connect a second chamber to the source of pressurized gas;

means for generating a reference signal representing a second predetermined pressure level;

means responsive to the pressure within the second chamber for generating a signal representative thereof;

means responsive to said reference and second chamber pressure signals for generating a third control signal to vent the first chamber when the pressure in the second chamber equals or exceeds said second predetermined pressure level;

means for generating a reference signal representing a third predetermined pressure level; and

means responsive to said third pressure level reference signal and said second chamber pressure signal for generating a fourth control signal to disconnect the second chamber from the source of pressurized gas.

2. An electronic circuit in accordance with claim 1 wherein said means for generating a third predetermined pressure level is enabled by said enabling signal.

3. An electronic circuit in accordance with claim 1 wherein said third predetermined pressure level is greater than said second predetermined pressure level.

4. An electronic circuit in accordance with claim 1 further including enabling means connected to said means for generating said enabling signal and manually operable for continuously generating said enabling signal whether or not the predetermined pressure level in the first chamber has been reached.

5. An electronic circuit in accordance with claim 1 including display means responsive to said second chamber pressure signal for visually displaying the amount of pressure within the second chamber.

6. In an apparatus intended for use in applying compressive pressure to a mammal extremity including a first inflatable chamber surrounding the extremity, a second inflatable chamber enclosing the first chamber, and pneumatic control means responsive to control signals and pneumatically connected to the first and second chambers for inflating and deflating the chambers from a source of pressurized gas such that the chambers apply compressive pressure to the extremity, an electronic circuit for regulating a pneumatic control means comprising:

switch means responsive to the pressure within a first chamber for generating an enabling signal when a first predetermined pressure level in the first chamber has been reached;

means for generating a signal representing a second predetermined pressure level in a second chamber;

means responsive to said enabling signal for generating a signal representing a third predetermined pressure level in the second chamber when said enabling signal is generated;

transducer means responsive to the pressure within the second chamber for generating a signal representative thereof; and

means responsive to said second chamber predetermined pressure level signals and said transducer signal for generating a first control signal to the pneumatic control means to connect a source of pressurized gas to the first chamber and responsive to the presence of said enabling signal for generating a second control signal to disconnect the first chamber and connect the second chamber to the source of pressurized gas.

7. An electronic circuit in accordance with claim 6 including means for generating a reference input signal and amplifier means connected between said transducer means and a comparator means for amplifying the difference of said transducer signal over the reference input signal.

8. An electronic circuit in accordance with claim 7 wherein said amplifier means includes means for adjusting said reference input signal whereby the output of said amplifier means is zero when the pressure within the second chamber is equal to the ambient pressure of the surroundings.

9. An electronic circuit in accordance with claim 8 including feedback means for shifting said reference input signal in accordance with said control signals.

10. An electronic circuit in accordance with claim 7 including timer control means responsive to said compartor means and connected to a solenoid means for generating timing signals to control the operation of said solenoid means.

11. An electronic circuit in accordance with claim 10 wherein said timer control means controls said solenoid means such that the second chamber applies compressive pressure against the extremity for a predetermined length of time.

12. An electronic circuit in accordance with claim 11 wherein said timer control means includes means for adjusting the length of time during which the second chamber applies compressive pressure against the extremity.

13. An electronic circuit in accordance with claim 10 wherein said timer control means controls said solenoid means such that the second chamber does not apply compressive pressure against the extremity for a predetermined length of time.

14. An electronic circuit in accordance with claim 13 wherein said timer control means includes means for adjusting the length of time during which the second chamber does not apply compressive pressure against the extremity.

15. In an apparatus intended for use in applying a dynamic pressure wave to a mammal extremity including an inflatable cylindrical tapered cone chamber surrounding the extremity, an inflatable cylindrical sleeve chamber enclosing the cone chamber, and pneumatic control means pneumatically connected to the cone chamber and the sleeve chamber for inflating and deflating the chambers from a source of pressurized gas according to a predetermined sequence such that the chambers apply a dynamic pressure wave against the extremity, an electronic circuit for regulating a pneumatic control means comprising:

switch means responsive to the pressure within a cone chamber for generating an enabling signal when a first predetermined pressure level has been reached;

means for generating a signal representing a predetermined wave pressure level;

means responsive to said enabling signal for generating a signal representing a predetermined final pressure level when said enabling signal is generated;

transducer means responsive to the pressure within a sleeve chamber for generating a signal representative thereof;

comparator means responsive to said predetermined wave and final pressure level signals and said sleeve pressure transducer signal for generating control signals according to a predetermined sequence; and

solenoid means connected to the pneumatic control means and responsive to said control signals for regulating the pneumatic control means according to the predetermined sequence.

16. An electronic circuit in accordance with claim 15 including enabling means connected to said switch means manually operable for continuously generating said enabling signal whether or not the predetermined cone pressure level has been reached.

17. An electronic circuit in accordance with claim 15 including display means responsive to said transducer signal for visually displaying the amount of pressure within the sleeve chamber.

18. An electronic circuit in accordance with claim 15 including means responsive to said enabling signal for generating a signal representing a predetermined high pressure level when said enabling signal is generated and said comparator means is further responsive to said high pressure level signal for generating one of said control signals.

19. An electronic circuit in accordance with claim 15 including means for generating a reference input signal and amplifier means connected between said transducer means and said comparator means for amplifying the difference of said transducer signal over said reference input signal.

20. An electronic circuit in accordance with claim 19 wherein said amplifier means includes means for adjusting said reference input signal whereby the output of said amplifier means is zero when the pressure within the sleeve chamber is equal to the ambient air pressure.

21. An electronic circuit in accordance with claim 20 including feedback means connected between said comparator means and said amplifier means for shifting said reference input signal in accordance with said control signals.

22. An electronic circuit in accordance with claim 15 including timer control means responsive to said comparator means and connected to said solenoid means for generating timing signals to control the operation of said solenoid means.

23. An electronic circuit in accordance with claim 22 wherein said timer control means controls said solenoid means such that the sleeve chamber applies the final pressure level against the extremity for a predetermined length of time.

24. An electronic circuit in accordance with claim 23 wherein said timer control means includes means for adjusting the length of said time during which the sleeve chamber applies the final pressure level against the extremity.

25. An electronic circuit in accordance with claim 22 wherein said timer control means controls said solenoid means such that the sleeve chamber does not apply any pressure against the extremity for a predetermined length of time.

26. An electronic circuit in accordance with claim 25 wherein said timer control means includes means for adjusting the length of time during which the sleeve chamber does not apply any pressure against the extremity.

27. An apparatus for applying compressive pressure to a mammal extremity comprising the combination of:

a first inflatable chamber surrounding the extremity;

a second inflatable chamber enclosing the first chamber;

pneumatic control means responsive to control signals and pneumatically connected to the first and second chambers for inflating and deflating the chambers from a source of pressurized gas such that the chambers apply compressive pressure to the extremity;

means responsive to the pressure within the first chamber for generating an enabling signal when a first predetermined pressure level has been reached; and

means connected to said pressure responsive means and responsive to the absence of said enabling signal for generating one of the control signals to the pneumatic control means to connect the source of pressurized gas to the first chamber, and responsive to the presence of said enabling signal for generating a second one of the control signals to disconnect the first chamber and connect the second chamber to the source of pressurized gas.

28. An apparatus in accordance with claim 27 further including means for generating a reference signal representing a second predetermined pressure level, means responsive to the pressure within the second chamber for generating a signal representative thereof, and means responsive to said reference and second chamber pressure signals for generating a third one of the control signals to vent the first chamber when the pressure in the second chamber equals or exceeds said second predetermined pressure level.

29. An apparatus in accordance with claim 28 further including means for generating a reference signal representing a third predetermined pressure level and means responsive to said third pressure level reference signal and said second chamber pressure signal for generating a fourth one of the control signals to disconnect the second chamber from the source of pressurized gas.