EP0684388A2 - Load-sensing active hydraulic control device - Google Patents
Load-sensing active hydraulic control device Download PDFInfo
- Publication number
- EP0684388A2 EP0684388A2 EP95202288A EP95202288A EP0684388A2 EP 0684388 A2 EP0684388 A2 EP 0684388A2 EP 95202288 A EP95202288 A EP 95202288A EP 95202288 A EP95202288 A EP 95202288A EP 0684388 A2 EP0684388 A2 EP 0684388A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- pressure
- load
- valve
- actuator
- valves
- 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.)
- Granted
Links
Images
Classifications
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/22—Hydraulic or pneumatic drives
- E02F9/2221—Control of flow rate; Load sensing arrangements
- E02F9/2232—Control of flow rate; Load sensing arrangements using one or more variable displacement pumps
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/22—Hydraulic or pneumatic drives
- E02F9/2221—Control of flow rate; Load sensing arrangements
- E02F9/2225—Control of flow rate; Load sensing arrangements using pressure-compensating valves
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/22—Hydraulic or pneumatic drives
- E02F9/2278—Hydraulic circuits
- E02F9/2296—Systems with a variable displacement pump
-
- 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
- F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
- F15B11/161—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load
- F15B11/162—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load for giving priority to particular servomotors or users
-
- 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
- F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
- F15B11/161—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load
- F15B11/163—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load for sharing the pump output equally amongst users or groups of users, e.g. using anti-saturation, pressure compensation
-
- 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
- F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
- F15B11/161—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load
- F15B11/166—Controlling a pilot pressure in response to the load, i.e. supply to at least one user is regulated by adjusting either the system pilot pressure or one or more of the individual pilot command pressures
-
- 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
- F15B2211/20546—Type of pump variable capacity
- F15B2211/20553—Type of pump variable capacity with pilot circuit, e.g. for controlling a swash plate
-
- 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
- F15B2211/25—Pressure control functions
-
- 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
- F15B2211/30525—Directional control valves, e.g. 4/3-directional control valve
- F15B2211/3053—In combination with a pressure compensating valve
- F15B2211/30555—Inlet and outlet of the pressure compensating valve being connected to the directional control valve
-
- 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
- F15B2211/32—Directional control characterised by the type of actuation
- F15B2211/329—Directional control characterised by the type of actuation actuated by fluid pressure
-
- 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
- F15B2211/40—Flow control
- F15B2211/405—Flow control characterised by the type of flow control means or valve
- F15B2211/40576—Assemblies of multiple valves
- F15B2211/40584—Assemblies of multiple valves the flow control means arranged in parallel with a check valve
-
- 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
- F15B2211/40—Flow control
- F15B2211/46—Control of flow in the return line, i.e. meter-out control
-
- 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
- F15B2211/40—Flow control
- F15B2211/47—Flow control in one direction only
- F15B2211/473—Flow control in one direction only without restriction in the reverse direction
-
- 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
- F15B2211/5153—Pressure control characterised by the connections of the pressure control means in the circuit being connected to an output member and a directional control valve
-
- 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
- F15B2211/55—Pressure control for limiting a pressure up to a maximum pressure, e.g. by using a pressure relief valve
-
- 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
- F15B2211/575—Pilot pressure control
-
- 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
- F15B2211/60—Circuit components or control therefor
- F15B2211/605—Load sensing circuits
- F15B2211/6051—Load sensing circuits having valve means between output member and the load sensing circuit
- F15B2211/6054—Load sensing circuits having valve means between output member and the load sensing circuit using shuttle 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
- F15B2211/60—Circuit components or control therefor
- F15B2211/635—Circuits providing pilot pressure to pilot pressure-controlled fluid circuit elements
- F15B2211/6355—Circuits providing pilot pressure to pilot pressure-controlled fluid circuit elements having valve means
-
- 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
- F15B2211/60—Circuit components or control therefor
- F15B2211/65—Methods of control of the load sensing pressure
- F15B2211/654—Methods of control of the load sensing pressure the load sensing pressure being lower than the load pressure
-
- 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
- F15B2211/71—Multiple output members, e.g. multiple hydraulic motors or cylinders
Definitions
- This invention relates to a load-sensing active hydraulic control device which is suitable for use for a power shovel or the like and includes a service port which permits a specific actuator as well as a main actuator constantly used to be connected thereto.
- a load-sensing active hydraulic control device which comprises a variable discharge pump, a plurality of actuators provided with change-over valves, respectively, which are connected in parallel to each other with respect to the variable discharge pump, a variable orifice of which a degree of opening is controlled depending on the amount of changing-over of each of the change-over valves, pressure compensating valves each arranged on a downstream side of the variable orifice for keeping a pressure difference between a load pressure and a pressure on the downstream side of the variable orifice constant, a load detecting passage for detecting a load pressure of each of the actuators, and shuttle valves each connected to the load detecting passage, whereby a maximum pressure selected by the shuttle valves is introduced into a regulator of the variable discharge pump to keep an output of the pump constant.
- the load-sensing active hydraulic control device of the present invention generally constructed as described above is characterized in that the load detecting passage communicating directly with the shuttle valve positioned on the most downstream side is provided with an on-off valve which is closed when a pressure on an upstream side of the shuttle on the most downstream side is equal to or exceeds a set pressure.
- the on-off valve when a pressure on the upstream side of the shuttle valve positioned on the most downstream side is equal to or exceeds a set pressure, the on-off valve is closed. Closing of the on-off valve prevents, even when a load pressure of the actuator connected to the shuttle valve on the most downstream side is increased, the load pressure from being introduced into the regulator of the variable discharge pump. Therefore, after the on-off valve is closed, the pressure compensating valve is caused to operate to exhibit a load-sensing function.
- a conventional load-sensing active hydraulic control device includes a main actuator 20 connected to normal actuator ports 17a and 18a and a specific sub-actuator 19 connected to service ports 17b and 18b.
- an actual power shovel includes in addition to the main actuator 20, a plurality of additional main actuators connected thereto, which are not shown in Figure 3 for the sake of brevity.
- the conventional control device further includes a variable discharge pump 1 provided with a main passage 2 to which a change-over valve 4 of the main actuator 20 and a change-over valve 3 of the sub-actuator 19 are connected in parallel.
- the change-over valves 3 and 4 are constructed in substantially the same manner, therefore, corresponding parts of the valves 4 and 3 are designated by like reference numerals.
- pressure compensating valves 8 respectively connected to the valves 3 and 4 are constructed in substantially the same manner, therefore, corresponding parts of the pressure compensating valves 8 are designated by the same reference numerals.
- the above-described change-over valves 3 and 4 are constructed into a seven-port and three- position structure. More particularly, the change-over valves 3 and 4 each include a first port 5 connected to the main passage 2, a second port 40, a third port 9 connected through the pressure compensating valve 8 to the second port 40, and a fourth port 41 connected to a return passage 12 connected to a tank T1.
- the change-over valves 3 and 4 each include fifth and sixth ports 10 and 11 connected to the main actuator 20 or sub-actuator 19 through the actuator ports 17a and 18a or service ports 17b and 18b. Further, the change-over valves 3 and 4 each include a seventh port 13 connected to shuttle valves 30, 31 and 32.
- the shuttle valves 30-32 are connected to all the change-over valves 3 and 4 one by one and adapted to select a high pressure from the change-over valves.
- the shuttle valve 30 positioned on the right side in Figure 3 is defined as being an upstream side of the system.
- reference character V designates a pilot valve, which functions to control a pilot pressure for changing over the change-over valve 4.
- a control cylinder 16 and a valve 15 co-operate with each other to constitute a regulator. Also, changing-over of each of the change-over valves 3 and 4 causes communication of the first port 5 and a second port 40 and a degree of opening of each of the ports 5 and 40 is determined depending on the amount of changing-over of the change-over valves 4 and 3. The communication of the first and second ports 5 and 40 forms a variable orifice.
- variable discharge pump 1 is adapted to control its tilting angle which is proportional to its discharge quantity depending on operation of the control cylinder 16.
- the control cylinder 16 is controlled depending on a change-over position of the valve 15.
- the valve 15 includes a first pilot chamber 15a connected to the shuttle valve 32 on the most downstream side and a second pilot chamber 15b connected to a discharge side of the variable discharge pump 1.
- the valve 15 thus constructed is kept at a normal position shown in Figure 3 by the action of a spring 42.
- the valve causes the control cylinder 16 to communicate with the tank T1 to keep the discharge quantity minimum when it is at the normal position.
- valve 15 When a discharge pressure or the pump 1 is increased to cause a build up of a pressure at the pilot chamber 15b to overcome the pressure at the pilot chamber 15a and the spring 42, the valve 15 is changed over (i.e. moved down in Figure 3) to a position so that its upper side in Figure 3 is operative, thereby to introduce the discharge pressure of the pump into the control cylinder 16.
- Such an action of the pressure on the control cylinder 16 causes the tilting angle of the variable discharge pump 1 to be reduced, resulting in the discharge quantity of the pump 1 being decreased.
- changing-over of each of the change-over valves 3 and 4 to a left side position causes communication of the first and second ports 5 and 40 through the variable discharge orifice.
- the degree of opening of the orifices, and hence of the communication depends on the amount of changing-over of each of the change-over valves 3 and 4.
- ports 5 and 40 Such communication between ports 5 and 40 causes hydraulic fluid to flow from the main passage 2 through the pressure compensating valves 8 (which are moved to the right) and then through the third port 9 to the fifth port 10. Also, on the side of the main actuator 20, the hydraulic fluid thus flowing to the fifth port 10 is then fed through the actuator port 17a to the main actuator 20. At this time, the fifth port 10 is caused to communicate with the seventh port 13 as well, so that a load pressure of the main actuator 20 is introduced through the seventh port 13 into the shuttle valve 31.
- the shuttle valve 31 compares the load pressure of the main actuator 20 with a load pressure selected by the shuttle valve 30 positioned on an upstream side of the shuttle valve 31, selecting higher one of both load pressures, which is then introduced into the shuttle valve 32 positioned on a downstream side of the shuttle valve 31.
- the shuttle valve 32 connected to the seventh port 13 of the change-over valve 3 on the side of the sub-actuator 19 is positioned on the most downstream side of the system, so that a maximum pressure of the system selected by the shuttle valve 32 is introduced into the pilot chamber 15a of the valve 15 functioning to control the tilting angle and hence the output of the variable discharge pump 1.
- the maximum pressure of the system and the discharge pressure of the variable discharge pump 1 are compared with each other to cause the discharge pressure of the variable discharge pump 1 to be kept increased in an amount of a corresponding to elastic force of the spring 42 as compared with the maximum pressure of the system. Also, the variable discharge pump 1 is controlled in such a manner that the power thereof is kept constant.
- the sub-actuator 19 is connected to the service ports 17b and 18b may typically comprise a breaker or scissors in the case of a shovel.
- the conventional control device constructed as described above exhibits the following disadvantages, for example, when a required maximum pressure or the sub-actuator 19 connected to the service ports 17b and 18b is lower than a required maximum pressure of the main actuator 20.
- the load pressure on the side of the sub-actuator 19 is increased to a level exceeding the required maximum pressure.
- the load pressure on the side of the sub-actuator 19 is caused to increase to a set maximum pressure of the system or the required maximum pressure of the main actuator 20.
- a load detecting passage 33 through which the seventh port 13 of the change-over valve 3 is connected to the shuttle valve 32 is provided with an on-off valve 34.
- the on-off valve 34 is kept an open position shown in Figure 1 by an action of a spring 35 and changed over to a closed position when a pilot pressure acting on a pilot chamber 34a overcomes elastic force of the spring 35.
- the pilot chamber 34a is connected through a passage 43 to an upstream side of the shuttle valve 32.
- P F is equal to or below P s p (P F ⁇ -_ P s p)
- the on-off valve 34 is kept open, so that the pressures P t and P F are compared with each other in the shuttle valve 32, resulting in higher one of the pressures P t and P F being selected, which is then fed back to the regulator.
- a maximum value of a load pressure of each of all the actuators is selected.
- a pressure fed back to the regulator depends on the pressure P F on the upstream side of the shuttle valve 32 irrespective of a value of the load pressure P t of the sub-actuator 19.
- the load pressure P t of the sub-actuator 19 is P F + a which is a discharge pressure of the pump or is fixed to a load pressure of the sub-actuator 19 which is a pressure within the discharge pressure of the pump 1.
- a pressure compensating valve 8 functions to carry out load-sensing control.
- the load-sensing active hydraulic control device of the present invention effectively prevents excessive consumption of energy when an additional actuator is used at a pressure lower than a maximum circuit pressure of the system, resulting in improving economical efficiency.
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Mechanical Engineering (AREA)
- Mining & Mineral Resources (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Fluid-Pressure Circuits (AREA)
- Operation Control Of Excavators (AREA)
Abstract
Description
- This invention relates to a load-sensing active hydraulic control device which is suitable for use for a power shovel or the like and includes a service port which permits a specific actuator as well as a main actuator constantly used to be connected thereto.
- It is an object of the present invention to provide a load-sensing active hydraulic control device which is capable of preventing excessive energy loss when an additional actuator is used under a pressure lower than a maximum circuit pressure of the system.
- In accordance with the present invention, there is provided a load-sensing active hydraulic control device which comprises a variable discharge pump, a plurality of actuators provided with change-over valves, respectively, which are connected in parallel to each other with respect to the variable discharge pump, a variable orifice of which a degree of opening is controlled depending on the amount of changing-over of each of the change-over valves, pressure compensating valves each arranged on a downstream side of the variable orifice for keeping a pressure difference between a load pressure and a pressure on the downstream side of the variable orifice constant, a load detecting passage for detecting a load pressure of each of the actuators, and shuttle valves each connected to the load detecting passage, whereby a maximum pressure selected by the shuttle valves is introduced into a regulator of the variable discharge pump to keep an output of the pump constant.
- The load-sensing active hydraulic control device of the present invention generally constructed as described above is characterized in that the load detecting passage communicating directly with the shuttle valve positioned on the most downstream side is provided with an on-off valve which is closed when a pressure on an upstream side of the shuttle on the most downstream side is equal to or exceeds a set pressure.
- In the load-sensing active hydraulic control device of the present invention constructed as described above, when a pressure on the upstream side of the shuttle valve positioned on the most downstream side is equal to or exceeds a set pressure, the on-off valve is closed. Closing of the on-off valve prevents, even when a load pressure of the actuator connected to the shuttle valve on the most downstream side is increased, the load pressure from being introduced into the regulator of the variable discharge pump. Therefore, after the on-off valve is closed, the pressure compensating valve is caused to operate to exhibit a load-sensing function.
- These and other objects and many of the attendant advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings in which like reference numerals designate like or corresponding parts throughout, wherein:-
- FIGURE 1 is a circuit diagram showing an embodiment of a load-sensing active hydraulic control device according to the present invention;
- FIGURE 2 is a graphical representation showing control characteristics of keeping an output of a variable discharge pump constant; and
- FIGURE 3 is a circuit diagram showing a conventional load-sensing active hydraulic control device.
- Referring first to Figure 3, a conventional load-sensing active hydraulic control device includes a
main actuator 20 connected tonormal actuator ports 17a and 18a and a specific sub-actuator 19 connected toservice ports 17b and 18b. Also, an actual power shovel includes in addition to themain actuator 20, a plurality of additional main actuators connected thereto, which are not shown in Figure 3 for the sake of brevity. - The conventional control device further includes a
variable discharge pump 1 provided with amain passage 2 to which a change-overvalve 4 of themain actuator 20 and a change-overvalve 3 of the sub-actuator 19 are connected in parallel. The change-overvalves valves pressure compensating valves 8 respectively connected to thevalves pressure compensating valves 8 are designated by the same reference numerals. - The above-described change-over
valves valves first port 5 connected to themain passage 2, asecond port 40, athird port 9 connected through thepressure compensating valve 8 to thesecond port 40, and afourth port 41 connected to areturn passage 12 connected to a tank T1. - The change-over
valves sixth ports 10 and 11 connected to themain actuator 20 or sub-actuator 19 through theactuator ports 17a and 18a orservice ports 17b and 18b. Further, the change-overvalves seventh port 13 connected toshuttle valves valves shuttle valve 30 positioned on the right side in Figure 3 is defined as being an upstream side of the system. - In Figure 3, reference character V designates a pilot valve, which functions to control a pilot pressure for changing over the change-over
valve 4. - A
control cylinder 16 and avalve 15 co-operate with each other to constitute a regulator. Also, changing-over of each of the change-overvalves first port 5 and asecond port 40 and a degree of opening of each of theports valves second ports - The above-described
variable discharge pump 1 is adapted to control its tilting angle which is proportional to its discharge quantity depending on operation of thecontrol cylinder 16. Thecontrol cylinder 16 is controlled depending on a change-over position of thevalve 15. Thevalve 15 includes afirst pilot chamber 15a connected to theshuttle valve 32 on the most downstream side and a second pilot chamber 15b connected to a discharge side of thevariable discharge pump 1. - The
valve 15 thus constructed is kept at a normal position shown in Figure 3 by the action of aspring 42. The valve causes thecontrol cylinder 16 to communicate with the tank T1 to keep the discharge quantity minimum when it is at the normal position. - When a discharge pressure or the
pump 1 is increased to cause a build up of a pressure at the pilot chamber 15b to overcome the pressure at thepilot chamber 15a and thespring 42, thevalve 15 is changed over (i.e. moved down in Figure 3) to a position so that its upper side in Figure 3 is operative, thereby to introduce the discharge pressure of the pump into thecontrol cylinder 16. Such an action of the pressure on thecontrol cylinder 16 causes the tilting angle of thevariable discharge pump 1 to be reduced, resulting in the discharge quantity of thepump 1 being decreased. - Then, changing-over of each of the change-over
valves second ports valves - Such communication between
ports main passage 2 through the pressure compensating valves 8 (which are moved to the right) and then through thethird port 9 to thefifth port 10. Also, on the side of themain actuator 20, the hydraulic fluid thus flowing to thefifth port 10 is then fed through the actuator port 17a to themain actuator 20. At this time, thefifth port 10 is caused to communicate with theseventh port 13 as well, so that a load pressure of themain actuator 20 is introduced through theseventh port 13 into theshuttle valve 31. - The
shuttle valve 31 compares the load pressure of themain actuator 20 with a load pressure selected by theshuttle valve 30 positioned on an upstream side of theshuttle valve 31, selecting higher one of both load pressures, which is then introduced into theshuttle valve 32 positioned on a downstream side of theshuttle valve 31. - Likewise, on the side of the sub-actuator 19, hydraulic fluid flowing through the
fifth port 10 is fed through the service port 17b to the sub-actuator 19. At this time, thefifth port 10 is caused to communicate with theseventh port 13 as well, therefore a load pressure of the sub-actuator 19 is introduced from theseventh port 13 into theshuttle valve 32. - The
shuttle valve 32 connected to theseventh port 13 of the change-overvalve 3 on the side of the sub-actuator 19 is positioned on the most downstream side of the system, so that a maximum pressure of the system selected by theshuttle valve 32 is introduced into thepilot chamber 15a of thevalve 15 functioning to control the tilting angle and hence the output of thevariable discharge pump 1. - Therefore, in the conventional device, the maximum pressure of the system and the discharge pressure of the
variable discharge pump 1 are compared with each other to cause the discharge pressure of thevariable discharge pump 1 to be kept increased in an amount of a corresponding to elastic force of thespring 42 as compared with the maximum pressure of the system. Also, thevariable discharge pump 1 is controlled in such a manner that the power thereof is kept constant. - The hydraulic fluid fed to the
actuator 20 and sub-actuator 19 as described above is then returned through the sixth port 11 andfourth port 41 to the tank T1. - Also, the sub-actuator 19 is connected to the
service ports 17b and 18b may typically comprise a breaker or scissors in the case of a shovel. - The conventional control device constructed as described above exhibits the following disadvantages, for example, when a required maximum pressure or the sub-actuator 19 connected to the
service ports 17b and 18b is lower than a required maximum pressure of themain actuator 20. - For example, when the sub-actuator 19 reaches a stroke end during use of the
main actuator 20 within a range of the required maximum pressure of the sub-actuator 19, the load pressure on the side of the sub-actuator 19 is increased to a level exceeding the required maximum pressure. Concurrently, the load pressure on the side of the sub-actuator 19 is caused to increase to a set maximum pressure of the system or the required maximum pressure of themain actuator 20. - Thus, in the conventional control device, when the load pressure of the sub-actuator is increased due to accidental arriving of the sub-actuator at the stroke end or the like, a circuit pressure of the system is excessively increased, resulting in energy loss being increased correspondingly.
- The present invention has been made in view of the foregoing disadvantage of the prior art, and is illustrated in Figure 1.
- Referring now to Figure 1, a
load detecting passage 33 through which theseventh port 13 of the change-overvalve 3 is connected to theshuttle valve 32 is provided with an on-offvalve 34. The on-offvalve 34 is kept an open position shown in Figure 1 by an action of aspring 35 and changed over to a closed position when a pilot pressure acting on a pilot chamber 34a overcomes elastic force of thespring 35. The pilot chamber 34a is connected through apassage 43 to an upstream side of theshuttle valve 32. - Thus, when a load pressure of a
main actuator 20 other than a sub-actuator 19 is equal to or exceeds a set pressure determined by thespring 35 of the on-offvalve 34, the on-offvalve 34 is closed. Such closing of the on-offvalve 34 prevents a load pressure of the sub-actuator 19 from affecting a discharge quantity of avariable discharge pump 1. - When the set pressure of the on-off
valve 34, as shown in Figure 2, is set at a position x which is defined immediately before a pump output control area in which an output of thevariable discharge pump 1 is kept constant, it is effectively prevented that a load pressure of the sub-actuator 19 is increased to an excessively high level to decrease a discharge quantity of thevariable discharge pump 1 when themain actuator 20 and sub-actuator 19 are concurrently operated. - Now, the manner of operation of the load-sensing active hydraulic control device of the illustrated embodiment thus constructed will be described hereinafter.
- The description will be made on the assumption that a pressure in the
load detecting passage 33, a pressure on an upstream side of theshuttle valve 32, a set pressure of the on-offvalve 34 and a final feedback pressure are indicated at Pf. PF, psp and P1max, respectively. - First, PF is equal to or below Psp (PF <-_Psp), the on-off
valve 34 is kept open, so that the pressures Pt and PF are compared with each other in theshuttle valve 32, resulting in higher one of the pressures Pt and PF being selected, which is then fed back to the regulator. Thus, under such circumstances, a maximum value of a load pressure of each of all the actuators is selected. - Then, PF is above Psp (PF> Psp), the on-off
valve 34 is kept closed, so that the pressure PF is selected in theshuttle valve 32 and then fed back to the regulator. - Under the circumstances, a pressure fed back to the regulator depends on the pressure PF on the upstream side of the
shuttle valve 32 irrespective of a value of the load pressure Pt of the sub-actuator 19. Thus, in a situation that, for example, even when the sub-actuator 19 reaches a stroke end, resulting in Pt being larger than PF, the load pressure Pt of the sub-actuator 19 is PF + a which is a discharge pressure of the pump or is fixed to a load pressure of the sub-actuator 19 which is a pressure within the discharge pressure of thepump 1. - When the sub-actuator 19 is solely used, the on-off
valve 34 is not changed over. Therefore, in this instance, apressure compensating valve 8 functions to carry out load-sensing control. Thus, when it is required to use the sub-actuator 19 at a high pressure, sole operation of the sub-actuator 19 permits it to be used at a maximum pressure of the system. - As can be seen from the foregoing, the load-sensing active hydraulic control device of the present invention effectively prevents excessive consumption of energy when an additional actuator is used at a pressure lower than a maximum circuit pressure of the system, resulting in improving economical efficiency.
- While a preferred embodiment of the invention has been described with a certain degree of particularity with reference to the drawings, obvious modifications and variations are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practised otherwise than as specifically described.
Claims (1)
Applications Claiming Priority (7)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP03357128A JP3124094B2 (en) | 1991-12-25 | 1991-12-25 | Control device for multiple actuators |
JP357128/91 | 1991-12-25 | ||
JP21224492A JPH0633904A (en) | 1992-07-16 | 1992-07-16 | Load sensitive control device |
JP212244/92 | 1992-07-16 | ||
JP250517/92 | 1992-08-26 | ||
JP04250517A JP3128775B2 (en) | 1992-08-26 | 1992-08-26 | Load-sensitive control device |
EP19920311770 EP0550257B1 (en) | 1991-12-25 | 1992-12-23 | Device for controlling multiple hydraulic actuators |
Related Parent Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP92311770.9 Division | 1992-12-23 | ||
EP19920311770 Division EP0550257B1 (en) | 1991-12-25 | 1992-12-23 | Device for controlling multiple hydraulic actuators |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0684388A2 true EP0684388A2 (en) | 1995-11-29 |
EP0684388A3 EP0684388A3 (en) | 1996-11-06 |
EP0684388B1 EP0684388B1 (en) | 1999-02-24 |
Family
ID=27329339
Family Applications (4)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP95202288A Expired - Lifetime EP0684388B1 (en) | 1991-12-25 | 1992-12-23 | Load-sensing active hydraulic control device |
EP95202286A Expired - Lifetime EP0684387B1 (en) | 1991-12-25 | 1992-12-23 | Load-sensing active hydraulic control device |
EP19920311770 Expired - Lifetime EP0550257B1 (en) | 1991-12-25 | 1992-12-23 | Device for controlling multiple hydraulic actuators |
EP95202287A Expired - Lifetime EP0684389B1 (en) | 1991-12-25 | 1992-12-23 | Control device for multiple hydraulic apparatus |
Family Applications After (3)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP95202286A Expired - Lifetime EP0684387B1 (en) | 1991-12-25 | 1992-12-23 | Load-sensing active hydraulic control device |
EP19920311770 Expired - Lifetime EP0550257B1 (en) | 1991-12-25 | 1992-12-23 | Device for controlling multiple hydraulic actuators |
EP95202287A Expired - Lifetime EP0684389B1 (en) | 1991-12-25 | 1992-12-23 | Control device for multiple hydraulic apparatus |
Country Status (2)
Country | Link |
---|---|
EP (4) | EP0684388B1 (en) |
DE (4) | DE69229966T2 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2012060742A1 (en) * | 2010-11-01 | 2012-05-10 | Volvo Construction Equipment Ab | A method for controlling a hydraulic system of a working machine |
CN104627880A (en) * | 2014-12-31 | 2015-05-20 | 中联重科股份有限公司 | Closed system, control method, hoisting system and crawler vehicle traveling system |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19719228A1 (en) * | 1997-05-07 | 1998-11-12 | Bosch Gmbh Robert | Hydraulic control device for load-independent control of a double-acting engine |
DE19831595B4 (en) * | 1998-07-14 | 2007-02-01 | Bosch Rexroth Aktiengesellschaft | Hydraulic circuit |
FR2807118B1 (en) * | 2000-03-28 | 2002-07-05 | Mannesmann Rexroth Sa | HYDRAULIC CIRCUIT FOR OPERATING MULTIPLE HYDRAULIC RECEIVERS |
CN110671376B (en) * | 2019-09-29 | 2021-03-12 | 中国矿业大学 | Engineering machinery load sensitive-inlet-outlet independent hydraulic system and control method thereof |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3710699C1 (en) * | 1987-03-31 | 1988-08-18 | Heilmeier & Weinlein | Hydraulic control device for a consumer group |
SE8803181D0 (en) * | 1988-09-09 | 1988-09-09 | Atlas Copco Ab | HYDRAULIC DRIVING SYSTEM WITH A PRIORITY FUNCTION FOR HYDRAULIC MOTORS |
WO1990014519A1 (en) * | 1989-05-24 | 1990-11-29 | Kabushiki Kaisha Komatsu Seisakusho | Hydraulic circuit apparatus |
-
1992
- 1992-12-23 DE DE1992629966 patent/DE69229966T2/en not_active Expired - Fee Related
- 1992-12-23 EP EP95202288A patent/EP0684388B1/en not_active Expired - Lifetime
- 1992-12-23 DE DE1992628489 patent/DE69228489T2/en not_active Expired - Fee Related
- 1992-12-23 EP EP95202286A patent/EP0684387B1/en not_active Expired - Lifetime
- 1992-12-23 EP EP19920311770 patent/EP0550257B1/en not_active Expired - Lifetime
- 1992-12-23 EP EP95202287A patent/EP0684389B1/en not_active Expired - Lifetime
- 1992-12-23 DE DE1992629968 patent/DE69229968T2/en not_active Expired - Fee Related
- 1992-12-23 DE DE1992625392 patent/DE69225392T2/en not_active Expired - Fee Related
Non-Patent Citations (1)
Title |
---|
None |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2012060742A1 (en) * | 2010-11-01 | 2012-05-10 | Volvo Construction Equipment Ab | A method for controlling a hydraulic system of a working machine |
CN103221617A (en) * | 2010-11-01 | 2013-07-24 | 沃尔沃建筑设备公司 | A method for controlling a hydraulic system of a working machine |
CN103221617B (en) * | 2010-11-01 | 2015-09-16 | 沃尔沃建筑设备公司 | For the method for the hydraulic system of Control Engineering machinery |
CN104627880A (en) * | 2014-12-31 | 2015-05-20 | 中联重科股份有限公司 | Closed system, control method, hoisting system and crawler vehicle traveling system |
Also Published As
Publication number | Publication date |
---|---|
EP0684388B1 (en) | 1999-02-24 |
DE69225392D1 (en) | 1998-06-10 |
EP0550257A1 (en) | 1993-07-07 |
DE69228489T2 (en) | 1999-09-30 |
DE69229966D1 (en) | 1999-10-14 |
EP0684389A3 (en) | 1996-10-30 |
DE69229968D1 (en) | 1999-10-14 |
EP0684387A3 (en) | 1996-10-30 |
DE69225392T2 (en) | 1998-09-03 |
EP0684388A3 (en) | 1996-11-06 |
EP0550257B1 (en) | 1998-05-06 |
DE69229968T2 (en) | 2000-03-09 |
DE69228489D1 (en) | 1999-04-01 |
EP0684387A2 (en) | 1995-11-29 |
EP0684387B1 (en) | 1999-09-08 |
DE69229966T2 (en) | 2000-03-09 |
EP0684389A2 (en) | 1995-11-29 |
EP0684389B1 (en) | 1999-09-08 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US5347811A (en) | Load-sensing active hydraulic control device for multiple actuators | |
US5209063A (en) | Hydraulic circuit utilizing a compensator pressure selecting value | |
US5571226A (en) | Hydraulic device for construction machinery | |
US6901754B2 (en) | Power conserving hydraulic pump bypass compensator circuit | |
US6241212B1 (en) | Hose rupture control valve unit | |
US4938022A (en) | Flow control system for hydraulic motors | |
US4518321A (en) | Power regulation device for a hydraulic pump | |
EP0684388B1 (en) | Load-sensing active hydraulic control device | |
US5433077A (en) | Actuator control device with meter-out valve | |
US7017470B2 (en) | Flow control apparatus for construction heavy equipment | |
US5212950A (en) | Hydraulic circuit with pilot pressure controlled bypass | |
JP3708711B2 (en) | Hydraulic control device | |
KR100212645B1 (en) | Discharge flow controlling unit in hydraulic pump | |
EP0586214B1 (en) | Control device for actuator | |
JPH11311204A (en) | Hydraulic control device | |
US4418709A (en) | Unloading valve for hi-lo-hydraulic system | |
JP3195095B2 (en) | 2-pump type load-sensitive circuit | |
JP3128775B2 (en) | Load-sensitive control device | |
JP3703308B2 (en) | Hydraulic control device | |
JP2652791B2 (en) | Flow control device | |
JP2652792B2 (en) | Flow control device | |
JPH11173304A (en) | Pressure oil control device | |
JPS6234961B2 (en) | ||
JPH06123303A (en) | Oil pressure controller | |
JPH0633904A (en) | Load sensitive control device |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
AC | Divisional application: reference to earlier application |
Ref document number: 550257 Country of ref document: EP |
|
AK | Designated contracting states |
Kind code of ref document: A2 Designated state(s): DE FR GB |
|
PUAL | Search report despatched |
Free format text: ORIGINAL CODE: 0009013 |
|
AK | Designated contracting states |
Kind code of ref document: A3 Designated state(s): DE FR GB |
|
17P | Request for examination filed |
Effective date: 19970411 |
|
GRAG | Despatch of communication of intention to grant |
Free format text: ORIGINAL CODE: EPIDOS AGRA |
|
17Q | First examination report despatched |
Effective date: 19980313 |
|
GRAG | Despatch of communication of intention to grant |
Free format text: ORIGINAL CODE: EPIDOS AGRA |
|
GRAG | Despatch of communication of intention to grant |
Free format text: ORIGINAL CODE: EPIDOS AGRA |
|
GRAH | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOS IGRA |
|
GRAH | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOS IGRA |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AC | Divisional application: reference to earlier application |
Ref document number: 550257 Country of ref document: EP |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): DE FR GB |
|
REF | Corresponds to: |
Ref document number: 69228489 Country of ref document: DE Date of ref document: 19990401 |
|
ET | Fr: translation filed | ||
PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
26N | No opposition filed | ||
REG | Reference to a national code |
Ref country code: GB Ref legal event code: IF02 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FR Payment date: 20061208 Year of fee payment: 15 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 20061220 Year of fee payment: 15 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 20061221 Year of fee payment: 15 |
|
GBPC | Gb: european patent ceased through non-payment of renewal fee |
Effective date: 20071223 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: DE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20080701 |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: ST Effective date: 20081020 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: GB Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20071223 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: FR Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20071231 |