EP4082501A1 - Système hydraulique pour un brancard de sauvetage mobile et brancard de sauvetage mobile - Google Patents

Système hydraulique pour un brancard de sauvetage mobile et brancard de sauvetage mobile Download PDF

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Publication number
EP4082501A1
EP4082501A1 EP22162064.4A EP22162064A EP4082501A1 EP 4082501 A1 EP4082501 A1 EP 4082501A1 EP 22162064 A EP22162064 A EP 22162064A EP 4082501 A1 EP4082501 A1 EP 4082501A1
Authority
EP
European Patent Office
Prior art keywords
working chamber
line
pressure
line arrangement
check valve
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP22162064.4A
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German (de)
English (en)
Inventor
Christian Hart
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hawe Hydraulik SE
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Hawe Hydraulik SE
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Filing date
Publication date
Application filed by Hawe Hydraulik SE filed Critical Hawe Hydraulik SE
Publication of EP4082501A1 publication Critical patent/EP4082501A1/fr
Pending legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B7/00—Systems in which the movement produced is definitely related to the output of a volumetric pump; Telemotors
    • F15B7/005—With rotary or crank input
    • F15B7/006—Rotary pump input
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61G—TRANSPORT, PERSONAL CONVEYANCES, OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
    • A61G1/00—Stretchers
    • A61G1/04—Parts, details or accessories, e.g. head-, foot-, or like rests specially adapted for stretchers
    • A61G1/052—Struts, spars or legs
    • A61G1/056—Swivelling legs
    • A61G1/0565—Swivelling legs simultaneously folding, e.g. parallelogram structures
    • A61G1/0567—Swivelling legs simultaneously folding, e.g. parallelogram structures folding in x-shape
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/08—Servomotor systems without provision for follow-up action; Circuits therefor with only one servomotor
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61G—TRANSPORT, PERSONAL CONVEYANCES, OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
    • A61G1/00—Stretchers
    • A61G1/02—Stretchers with wheels
    • A61G1/0237—Stretchers with wheels having at least one swivelling wheel, e.g. castors
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61G—TRANSPORT, PERSONAL CONVEYANCES, OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
    • A61G1/00—Stretchers
    • A61G1/04—Parts, details or accessories, e.g. head-, foot-, or like rests specially adapted for stretchers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
    • F15B13/025—Pressure reducing valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
    • F15B13/027—Check valves
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61G—TRANSPORT, PERSONAL CONVEYANCES, OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
    • A61G1/00—Stretchers
    • A61G1/02—Stretchers with wheels
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/20507—Type of prime mover
    • F15B2211/20515—Electric motor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/2053—Type of pump
    • F15B2211/20561—Type of pump reversible
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/27—Directional control by means of the pressure source
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30505—Non-return valves, i.e. check valves
    • F15B2211/3051—Cross-check valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/505—Pressure control characterised by the type of pressure control means
    • F15B2211/50509—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means
    • F15B2211/50518—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means using pressure relief valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/515—Pressure control characterised by the connections of the pressure control means in the circuit
    • F15B2211/5159—Pressure control characterised by the connections of the pressure control means in the circuit being connected to an output member and a return line
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
    • F15B2211/7051—Linear output members
    • F15B2211/7053—Double-acting output members
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/76—Control of force or torque of the output member
    • F15B2211/761—Control of a negative load, i.e. of a load generating hydraulic energy
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/785—Compensation of the difference in flow rate in closed fluid circuits using differential actuators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/80—Other types of control related to particular problems or conditions
    • F15B2211/895—Manual override

Definitions

  • the present invention relates to a hydraulic system for a mobile rescue bed with a hydraulic cylinder, a tank and a pump. Furthermore, the invention relates to a mobile rescue bed with such a hydraulic system.
  • the hydraulic cylinder regularly has a piston with at least one piston rod, a first working chamber and a second working chamber which is separated from the first working chamber by the piston.
  • the first work space is usually the piston work space and the second work space is usually the rod work space.
  • the first working space is connected to the pump via a first line arrangement and the second working space is connected to the pump via a second line arrangement.
  • the pump can optionally pressurize the first working chamber via the first line arrangement or the second working chamber via the second line arrangement.
  • hydraulic fluid can flow out of the first working chamber via the first line arrangement, in that the first line arrangement has a first check valve that can be opened when pressure is applied to the second line arrangement.
  • hydraulic fluid flows out of the second working chamber via the second line arrangement. The hydraulic fluid flowing out of the working chambers flows to the tank or is sucked in again directly by the pump.
  • the first check valve can “stutter” if an additional force acts in the retraction direction of the hydraulic cylinder. This condition is referred to below as a pulling load and can be caused, for example, by a patient lying on the patient couch.
  • the control pressure for opening the first check valve is increased by pressurizing the second line arrangement and thus the second working space (ie the bar working space) is generated.
  • the hydraulic fluid volume displaced from the first working chamber ie from the piston working chamber
  • the excess volume fraction must be taken from the circuit and fed into the tank. Due to a pulling load, however, it can happen that the pump volume flow then generated by the pump is no longer sufficient to subsequently deliver the hydraulic fluid volume required for the second working chamber. As a result, the control pressure applied to the first check valve collapses and the first check valve closes.
  • This stuttering of the first check valve can damage the seat of the valve and cause the entire hydraulic system to vibrate. Furthermore, this also results in an uncomfortable situation for the operator and the patient.
  • a nozzle can be integrated in the first line arrangement in order to reduce the retraction speed of the hydraulic cylinder.
  • An example hydraulic circuit diagram is in here 1 shown.
  • the hydraulic system 101 has a hydraulic cylinder 102 , a tank 103 and a pump 104 .
  • the hydraulic cylinder 102 has a piston 105 with a piston rod 106 which separates a first working chamber 107 from a second working chamber 108 .
  • the first working space 107 is the piston working space and the second working space 108 is the rod working space.
  • the piston rod 106 is connected to the patient bed (not shown) in order to change its height in relation to the chassis (not shown).
  • the piston working chamber 107 can be optionally connected to the pump 104 or the tank 103 via a first line arrangement 109 .
  • the rod working space 108 can also be connected to the pump 104 or the tank 103 via a second line arrangement 110 .
  • the connection between the line arrangements 109, 110 and the tank 103 or the pump 104 takes place via appropriate valves, although other solutions are also conceivable, such as those from FIG WO 2019/ 201579 A1 known.
  • a first check valve 111 is arranged in the first line arrangement 109 and a second check valve 112 is arranged in the second line arrangement 110 .
  • the first check valve 111 is connected via a first control line 113 to the second line arrangement 110 and the second check valve 112 is connected via a second control line 114 to the first Line arrangement 109 connected, so that the respective check valve 111, 112 is turned on when pressure is applied to the respective line arrangement 109, 110. If, for example, the second line arrangement 110 is pressurized in order to retract the hydraulic cylinder 102, the pressure in the second line arrangement 110 is reported to the first check valve 111 via the first control line 113 and this is consequently opened.
  • the hydraulic fluid volume from the piston working chamber 107 can thus flow off to the tank 103 via the first line arrangement 109 . Furthermore, a nozzle 115 is arranged in the first line arrangement 109 between the first check valve 111 and the piston working chamber 107 . The volume flow is limited via this nozzle 115, so that the retraction speed of the hydraulic cylinder 102 is limited.
  • the regarding 1 The solution described effectively prevents the first check valve from stuttering.
  • the nozzle 115 is active both when retracting and when extending the hydraulic cylinder 102 .
  • the nozzle active is the nozzle active. This consumes unnecessary energy, generates heat and reduces retraction speed.
  • the hydraulic system according to the invention is particularly distinguished from the solutions known from the prior art in that the second line arrangement has a first branch line and a second branch line.
  • the first branch line is connected to the pump and the second branch line is connected to the tank.
  • a pressure valve is arranged in the second branch line, which opens when pressure is applied to the second line arrangement via the pump, so that the pressure in the second line arrangement is limited to a pressure sufficient to open the first check valve.
  • the pressure valve is preferably a pressure-limiting valve and preferably opens at a pressure of at most 100 bar, in particular at most 75 bar.
  • the pressure in the second line arrangement is thus limited to the pressure set at the pressure valve, which is below the pump pressure. This limited pressure is sufficient to open the first check valve. At the same time, the excess volume flow can be routed to the tank via the pressure valve and thus removed from the circuit. Thus, even with a pulling load, the control pressure present at the first check valve does not collapse and consequently the first check valve also does not stutter. Sufficient speed can also be achieved in this way both with the retract and with the lower load.
  • a second check valve is preferably arranged in the first branch line, with the second branch line branching off from the second line arrangement downstream of the second check valve, viewed in the direction of flow from the pump to the hydraulic cylinder.
  • the second check valve causes the piston rod working chamber to be relieved via the pressure valve to the tank when the hydraulic cylinder is extended.
  • the second line arrangement preferably has a third branch line, the third branch line being connected to the tank and branching off from the first branch line.
  • a nozzle is arranged in the third branch line. This nozzle can be used to ensure that the control pressure for opening the first check valve is reliably reduced when the retraction of the cylinder is stopped and the first check valve is reliably closed. This effectively prevents the patient couch from sagging.
  • the third branch line expediently has a bypass line bypassing the nozzle and having a fourth non-return valve.
  • the first line arrangement has a fourth branch line connected to the tank, with a fourth check valve being arranged in the fourth branch line, which can be opened when pressure is applied to the second line arrangement. It is particularly advantageous here if a hydraulic resistance is arranged in the fourth branch line in the direction of flow from the first working chamber to the tank upstream of the fourth check valve in the fourth branch line, the hydraulic resistance being in particular a nozzle. In this way it can be ensured that a partial volume flow of the excess volume flow is diverted directly into the tank. In this way, the power loss can be reduced overall, since the entire excess volume flow does not have to flow off to the tank via the pressure valve.
  • the object is achieved with a mobile rescue bed according to claim 10.
  • the rescue bed has a hydraulic system as described above.
  • FIG 2 a hydraulic circuit diagram of a hydraulic system 1 according to the invention for a mobile rescue bed 50 is shown.
  • the rescue bed 50 is described below with reference to FIG 3 described in more detail.
  • the hydraulic system 1 has a hydraulic cylinder 2 , a tank 3 and a pump 4 .
  • the tank 3 is designed as a hydraulic accumulator, although other designs are also conceivable, for example as in FIG 1 shown.
  • the hydraulic cylinder 2 has a piston 5 with a piston rod 6 which separates a first working space 7 and a second working space 8 .
  • the first working space 7 is the piston working space and the second working space 8 is the rod working space.
  • the piston working chamber 7 is connected to the pump 4 via a first line arrangement 9 and the rod working chamber 8 is connected to the pump 4 via a second line arrangement 10 .
  • the pump 4 is designed in such a way that either the piston working chamber 7 can be pressurized via the first line arrangement 9 or the rod working chamber 8 can be pressurized via the second line arrangement 10 .
  • the hydraulic fluid of the respective other working chamber 7, 8 that is not pressurized flows out via the respective line arrangement 9, 10.
  • the hydraulic system 1 has a first check valve 11 arranged in the first line arrangement.
  • the first check valve 11 is designed as a spring-loaded check valve and is connected to the second line arrangement 10 via a first control line 23 in such a way that the first check valve 11 is opened when the second line arrangement 10 or the rod working chamber 8 is pressurized to retract the hydraulic cylinder 2.
  • the hydraulic fluid displaced from the piston working chamber 7 can thus be sucked in directly, at least partially, via the first line arrangement 9 and the pump 4 .
  • the second line arrangement 10 can be seen to have a first branch line 13 and a second branch line 14 .
  • the first branch pipe 13 is connected to the pump 4 and a second check valve 12 is arranged in the first branch pipe 13 .
  • the second check valve 12 is also designed as a spring-loaded check valve in this embodiment.
  • the second branch line 14 branches off downstream of the second check valve 12 in the direction of flow from the pump 4 to the rod working chamber 8 .
  • the first control line 23 branches off upstream of the second check valve 12 .
  • the second branch line 14 is connected to the tank and a pressure valve 15 designed as a pressure relief valve is arranged in the second branch line 14 .
  • the pressure-limiting valve 15 limits the pressure in the second line arrangement 10 to a maximum of 100 bar, in particular a maximum of 75 bar. This pressure is sufficient to open the first check valve 11 via the first control line 23 .
  • the hydraulic cylinder 2 is retracted, the excess volume of hydraulic fluid is drained off via the pressure-limiting valve 15 to the tank. This prevents the first check valve 11 from stuttering due to a collapsing control pressure in the first control line 23 .
  • the second line arrangement 10 has a third branch line 16 which branches off from the first branch line 13 between the pump 3 and the second check valve 12 and is connected to the tank 3 .
  • a nozzle 17 is arranged in the third branch line 16 . This nozzle 17 is chosen to be very small.
  • the third branch line 16 has a bypass line 18 bypassing the nozzle 17 and having a third check valve 19, which is also designed as a spring-loaded check valve.
  • the first line arrangement 9 has a fourth branch line 20 which is connected to the tank 3 .
  • the fourth branch line 18 branches off in the direction of flow from the pump 3 to the piston working chamber 7 downstream of the first check valve 11 .
  • a fourth, likewise spring-loaded check valve 21 is arranged in the fourth branch line 20 and is connected to the second line arrangement 10 via a second control line 24 in such a way that it is opened when the second line arrangement 10 is pressurized.
  • the second control line 24 branches off between the pump 3 and the second check valve 12 from the second line arrangement 10 or the first branch line 13 .
  • a hydraulic resistance 22 designed as a nozzle is arranged in front of the fourth check valve 21 . In this way, when the hydraulic cylinder 2 is retracted, a defined partial volume of the hydraulic fluid volume displaced from the piston working chamber 7 can be removed from the circuit. Overall, this enables the hydraulic cylinder 2 to be retracted more quickly.
  • the hydraulic system 1 has a manually operable emergency valve 25 which connects the piston working chamber 7 and the rod working chamber 8 directly to the tank 3 .
  • a nozzle 26 is arranged between the rod working chamber 8 and the emergency valve 25 .
  • the hydraulic system 1 also has an emergency pressure relief valve 27 which connects the first line arrangement 9 to the tank 3 .
  • the emergency pressure relief valve 27 is set to a pressure of more than 200 bar and prevents damage to the hydraulic system 1 that could otherwise occur if the hydraulic cylinder 2 is blocked from the outside or if the hydraulic cylinder 2 moves to the end stop. Furthermore, also due to the fact that, for example, temperature or solar radiation-related pressure increases could occur.
  • the hydraulic system 1 also has an optional external connection 28 and an optional pressure gauge 29 .
  • the hydraulic system 1 also has an after-suction arrangement 30 via which the pump 4 can suck hydraulic fluid directly from the tank 3 .
  • An after-suction arrangement 30 via which the pump 4 can suck hydraulic fluid directly from the tank 3 .
  • a variant with two spring-loaded check valves is shown, although other variants are also conceivable, for example with a shuttle valve.
  • FIG. 1 is a side view of a mobile rescue stretcher 50 according to the invention.
  • the rescue stretcher 50 has a patient stretcher 51, a chassis 52, a scissor lift structure 53 and a hydraulic system 1 as described above.
  • the hydraulic cylinder 2 is attached to the scissor lift construction 53 and the chassis 52 in such a way that a pressurization of the first line arrangement 9 and consequently of the piston working chamber 7 raises the patient bed 51 relative to the chassis 52 .
  • the patient bed 51 is lowered relative to the chassis 52 when pressure is applied to the second line arrangement 10 and consequently to the rod working space 8 .
  • the pump 4 is controlled in such a way that the first line arrangement 9 is pressurized.
  • the first check valve 11 is opened and hydraulic fluid flows into the piston working chamber 7 and the hydraulic cylinder 2 moves out.
  • the displaced from the rod working chamber 8 hydraulic fluid can flow through the second line arrangement 10 and the second branch line 14 to the tank 3, since the Pressure exceeds the pressure set at the pressure relief valve 15 and the pressure relief valve 15 therefore opens.
  • the pump 3 sucks in hydraulic fluid from the tank 3 via the fourth branch line 16 and the bypass line 18 as well as via the suction arrangement 30 .
  • the pump 3 is switched off and the position of the hydraulic cylinder 2 is held via the first check valve 11 and the fourth check valve 21 .
  • the pump 4 is controlled in such a way that the second line arrangement 10 is pressurized.
  • the first check valve 11 and the fourth check valve 21 are opened via the control pressure reported through the first and second control lines 23 , 24 .
  • the hydraulic fluid displaced from the piston working chamber 7 can thus be sucked in again directly via the pump 4 or partially flow off via the fourth branch line 20 to the tank 3 .
  • the pressure in the second line arrangement 10 or in the first branch line 13 opens the second check valve 12 and hydraulic fluid can flow into the rod working chamber 8 .
  • the excess volume fraction of the hydraulic fluid flowing out of the piston working chamber 7 is diverted to the tank 3 via the pressure-limiting valve 15 and the pressure in the second line arrangement 9 is limited to the pressure set at the pressure-limiting valve 15 .
  • the pump 4 is stopped.
  • the second check valve 12 closes and control pressure in the first control line 23 and in the second control line 24 is relieved via the third branch line 16 and the nozzle 17 to the tank 3 .
  • the first check valve 11 and the fourth check valve 21 close and the position of the patient bed 51 is held.
  • the above functional descriptions of the mobile rescue bed 50 also apply accordingly to rapid retraction or extension (the so-called “extend”) of the chassis 51, i.e. to a situation in which no patient is accommodated on the patient bed 51. This is necessary, for example, when the rescue couch 51 is to be hung in an ambulance or is to be removed from the ambulance.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Invalid Beds And Related Equipment (AREA)
EP22162064.4A 2021-04-29 2022-03-15 Système hydraulique pour un brancard de sauvetage mobile et brancard de sauvetage mobile Pending EP4082501A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE102021204291.0A DE102021204291B3 (de) 2021-04-29 2021-04-29 Hydrauliksystem für eine fahrbare Rettungsliege und fahrbare Rettungsliege

Publications (1)

Publication Number Publication Date
EP4082501A1 true EP4082501A1 (fr) 2022-11-02

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Family Applications (1)

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EP22162064.4A Pending EP4082501A1 (fr) 2021-04-29 2022-03-15 Système hydraulique pour un brancard de sauvetage mobile et brancard de sauvetage mobile

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US (1) US11679043B2 (fr)
EP (1) EP4082501A1 (fr)
CN (1) CN115263829A (fr)
DE (1) DE102021204291B3 (fr)

Citations (5)

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US20060075558A1 (en) * 2004-09-24 2006-04-13 Lambarth Clifford E Ambulance cot and hydraulic elevating mechanism therefor
US20090172883A1 (en) * 2004-06-14 2009-07-09 Ferno-Washington, Inc. Electro-hydraulically powered lift ambulance cot
US20150260204A1 (en) * 2012-10-10 2015-09-17 Kayaba Industry Co., Ltd. Cylinder driving apparatus
US20180303685A1 (en) * 2017-04-21 2018-10-25 Stryker Corporation Patient handling apparatus with hydraulic control system
WO2019201579A1 (fr) 2018-04-19 2019-10-24 HAWE Altenstadt Holding GmbH Brancard de sauvetage mobile

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AT409656B (de) * 1999-10-18 2002-10-25 Hoerbiger Hydraulik Hydraulische betätigungsanordnung
US7254945B1 (en) * 2006-02-27 2007-08-14 Kayaba Industry Co., Ltd. Operate check valve and hydraulic driving unit
US11896531B2 (en) * 2019-10-28 2024-02-13 Stryker Corporation Hydraulic circuit for a patient handling apparatus

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090172883A1 (en) * 2004-06-14 2009-07-09 Ferno-Washington, Inc. Electro-hydraulically powered lift ambulance cot
US20060075558A1 (en) * 2004-09-24 2006-04-13 Lambarth Clifford E Ambulance cot and hydraulic elevating mechanism therefor
US20150260204A1 (en) * 2012-10-10 2015-09-17 Kayaba Industry Co., Ltd. Cylinder driving apparatus
US20180303685A1 (en) * 2017-04-21 2018-10-25 Stryker Corporation Patient handling apparatus with hydraulic control system
WO2019201579A1 (fr) 2018-04-19 2019-10-24 HAWE Altenstadt Holding GmbH Brancard de sauvetage mobile

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Publication number Publication date
US20220347023A1 (en) 2022-11-03
US11679043B2 (en) 2023-06-20
DE102021204291B3 (de) 2022-06-15
CN115263829A (zh) 2022-11-01

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