EP1528262A1 - Kran und Methode zur Steuerung des Krans - Google Patents

Kran und Methode zur Steuerung des Krans Download PDF

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Publication number
EP1528262A1
EP1528262A1 EP03024717A EP03024717A EP1528262A1 EP 1528262 A1 EP1528262 A1 EP 1528262A1 EP 03024717 A EP03024717 A EP 03024717A EP 03024717 A EP03024717 A EP 03024717A EP 1528262 A1 EP1528262 A1 EP 1528262A1
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EP
European Patent Office
Prior art keywords
pressure
side chamber
piston rod
conduit
cylinder
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.)
Withdrawn
Application number
EP03024717A
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English (en)
French (fr)
Inventor
Peter ASTRÖM
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.)
Hiab AB
Original Assignee
Hiab AB
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Hiab AB filed Critical Hiab AB
Priority to EP03024717A priority Critical patent/EP1528262A1/de
Publication of EP1528262A1 publication Critical patent/EP1528262A1/de
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66C—CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
    • B66C23/00—Cranes comprising essentially a beam, boom, or triangular structure acting as a cantilever and mounted for translatory of swinging movements in vertical or horizontal planes or a combination of such movements, e.g. jib-cranes, derricks, tower cranes
    • B66C23/54—Cranes comprising essentially a beam, boom, or triangular structure acting as a cantilever and mounted for translatory of swinging movements in vertical or horizontal planes or a combination of such movements, e.g. jib-cranes, derricks, tower cranes with pneumatic or hydraulic motors, e.g. for actuating jib-cranes on tractors
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66C—CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
    • B66C13/00—Other constructional features or details
    • B66C13/18—Control systems or devices
    • 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
    • F15B11/02—Systems essentially incorporating special features for controlling the speed or the actuating force of an output member
    • F15B11/024—Systems essentially incorporating special features for controlling the speed or the actuating force of an output member by means of differential connection of the servomotor lines, e.g. regenerative circuits
    • 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
    • F15B11/02—Systems essentially incorporating special features for controlling the speed or the actuating force of an output member
    • F15B11/024—Systems essentially incorporating special features for controlling the speed or the actuating force of an output member by means of differential connection of the servomotor lines, e.g. regenerative circuits
    • F15B2011/0243—Systems essentially incorporating special features for controlling the speed or the actuating force of an output member by means of differential connection of the servomotor lines, e.g. regenerative circuits the regenerative circuit being activated or deactivated automatically
    • 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
    • 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
    • F15B2211/3056—Assemblies of multiple valves
    • F15B2211/30565—Assemblies of multiple valves having multiple valves for a single output member, e.g. for creating higher valve function by use of multiple valves like two 2/2-valves replacing a 5/3-valve
    • F15B2211/3058—Assemblies of multiple valves having multiple valves for a single output member, e.g. for creating higher valve function by use of multiple valves like two 2/2-valves replacing a 5/3-valve having additional valves for interconnecting the fluid chambers of a double-acting actuator, e.g. for regeneration mode or for floating mode
    • 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
    • F15B2211/505—Pressure control characterised by the type of pressure control means
    • F15B2211/50563—Pressure control characterised by the type of pressure control means the pressure control means controlling a differential pressure
    • F15B2211/50581—Pressure control characterised by the type of pressure control means the pressure control means controlling a differential pressure using counterbalance 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
    • F15B2211/70—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
    • F15B2211/7057—Linear output members being of the telescopic type
    • 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
    • F15B2211/7114—Multiple output members, e.g. multiple hydraulic motors or cylinders with direct connection between the chambers of different actuators
    • F15B2211/7128—Multiple output members, e.g. multiple hydraulic motors or cylinders with direct connection between the chambers of different actuators the chambers being connected in parallel
    • 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
    • F15B2211/75—Control of speed of the output member

Definitions

  • the present invention relates to a crane, comprising at least one hydraulic cylinder/ piston unit in which a piston rod is displaceable in a cylinder and in which a piston that is connected to the piston rod separates the cylinder chamber in a cylinder side chamber and a piston rod side chamber that is provided with an opening in the cylinder gable in order to permit a displacement of the piston rod out of and into the cylinder, a first conduit for conducting a pressure fluid between a pressure fluid source and the cylinder side chamber, a second conduit for conducting pressure fluid between the piston rod side chamber and a pressure fluid reservoir that has a lower pressure than the pressure fluid source, a third conduit for regenerative conduction of a pressure fluid from the piston rod side chamber to the cylinder side chamber when pressure fluid is delivered from the pressure fluid source to the cylinder side chamber for the purpose of ejecting the piston rod out of the cylinder, and means for breaking the regenerative conduction of pressure fluid at a pre-determined moment.
  • the present invention also relates to a method of controlling such a crane, wherein, upon a predetermined condition during ejection of the piston rod in connection to delivery of the pressure fluid to the cylinder side chamber, the regenerative flow through the third conduit is reduced and the pressure fluid is permitted to flow through the second conduit towards the reservoir.
  • the invention is applicable to all types of cranes, but is particularly applicable to cranes for lifting piece goods, presenting a considerable overhang when in an extended position.
  • the invention will therefore be described by way of example with reference to such an application.
  • hydraulic unit according to the invention can be utilized for the purpose of imparting swinging movements as well as longitudinal movements of any beam that forms a part of the crane.
  • the invention is particularly suitable for cranes that comprise a plurality of beams that are arranged in a telescopic way.
  • the beams are displaced in relation to each other by means of a plurality of hydraulic cylinder/piston units.
  • the object of the present invention is achieved by means of a crane as initially defined, characterised in that, in at least one of the first and the second conduit, there is arranged a pressure delimiting member for delimiting or reducing the pressure in the cylinder side chamber and the piston rod side chamber respectively.
  • a relatively high pressure (higher than otherwise) can be applied to the cylinder side chamber up to the moment when regenerative operation is ended.
  • the individual piston rod is designed to stand a maximum power or force.
  • regenerative operation is performed up to an absolute pressure on the cylinder side that is substantially above said maximum value. This is possible thanks to the maintained, i.e. delimited, pressure on the piston rod side instead.
  • the pressure in the cylinder side chamber can remain high if the pressure delimiting member is provided in the second conduit between the piston rod side chamber and the low pressure reservoir. If, on the other hand, the pressure delimiting member is arranged in the first conduit, it should be of a controllable type that is actuated upon the change to non-regenerative operation in order to permit a reduction of the pressure in the cylinder side chamber while the pressure in the piston rod side chamber is reduced, by means of free flow, to generally the same pressure as the one in the reservoir, which is preferably equal to the atmospheric pressure.
  • the object of the invention is also achieved by means of the inventive method as initially defined, which is characterised in that, upon the reaching of said condition, the pressure in the piston rod side chamber is delimited to a pressure that is higher than the pressure in the reservoir but lower than the pressure in the cylinder side chamber, or that the pressure in the cylinder side chamber is reduced while the pressure in the piston rod side chamber is reduced generally to the pressure of the reservoir.
  • Fig. 1 shows a crane according to the invention.
  • the crane comprises a plurality of beams 1 that are telescopically arranged in relation to each other in order to permit adjustment of its length from a shortest length, in which the beams are inserted into each other, to a maximum length when they are fully extended.
  • the crane comprises a plurality of hydraulic units 2 for driving the beams 1 in way known per se.
  • each hydraulic unit 2 comprises a cylinder 3 and a piston 4 with a piston rod 5.
  • the piston divides the cylinder chamber into a cylinder side chamber 6 and a piston rod side chamber 7.
  • the piston area is larger on the cylinder side than on the piston rod side.
  • the piston rod 5 is arranged to perform a reciprocating movement through an opening 8 in a gable 9 of the cylinder 3 for its operation.
  • the hydraulic system or circuit can be divided into a cylinder side and a piston rod side.
  • the crane for the actuation of the hydraulic unit the crane comprises a first conduit 10 that connects the cylinder side chambers 6 of the hydraulic units 2 with a pressure fluid source 11 via a direction valve 12 in a way known per se.
  • the cylinder side chambers 6 are connected in parallel with each other in relation to the source 11.
  • the first conduit can, as here, be divided in a plurality of intermediate conduits, each of which leads from the cylinder side chamber of one hydraulic unit to a cylinder side chamber of another hydraulic unit in a bus-type arrangement. Therefore, the cylinder side chambers 6 may be regarded as an integrated part of the first conduit 10.
  • the fluid pressure in the pressure fluid source may, for example, be 28 MPa.
  • the crane On the piston rod side the crane comprises a second conduit 13 that connects the piston rod side chamber 7 of a first one of the hydraulic units 2 with a low pressure reservoir 14 for drainage of pressure fluid from the chamber 7 to the reservoir 14.
  • the fluid pressure in the reservoir 14 may, as here, be equal to atmospheric pressure.
  • the second conduit 13 can, as here, be divided in a plurality of intermediate conduits, each of which leads from the piston rod side chamber 7 of one hydraulic unit 2 to a piston rod side chamber 7 of another hydraulic unit 2 in a bus-type arrangement. Therefore, the piston rod side chambers 6 may be regarded as an integrated part of the second conduit 13.
  • the third conduit 15 is also provided a third conduit 15 that in one end is connected to the first conduit 10 and in another end is connected the second conduit 13.
  • the third conduit 15 is arranged for controlled regenerative pressure fluid flow from the piston rod side chamber 7 to the cylinder side chamber 6 during extension of the crane.
  • the third conduit 15 may be connected directly to the cylinder side chamber 6, since the latter may be regarded as an integral part of the first conduit 10, and directly to the piston rod side chamber 7 since the latter may be regarded as an integral part of the second conduit 13.
  • a pressure delimiting member 16 in the second conduit 13 for the purpose of reducing the pressure on the piston rod chamber side upon a given pressure condition in the first conduit 10.
  • valve 17 a pilot-controlled non return valve 17 in the second conduit 13.
  • valve 17 Upon activation of valve 17, it will permit a flow throughthe second conduit 13 towards the reservoir.
  • the regenerative flow through the third conduit 15 is stopped, or at least substantially reduced, as valve 17 is actuated in order to permit a flow of fluid from the piston rod side chamber 7 to the reservoir 14.
  • full extension of the hydraulic unit 2 in question can be attained with a remaining high or even further increased pressure on the cylinder side and a reduced, but still substantial, pressure on the piston rod side thanks to the pressure delimiting member 16.
  • the pressure delimiting member 16 should comprise a counter pressure valve and may comprise any kind of throttle or constriction. It only opens for passage when the pressure in the piston rod side chamber exceeds a given value, in this example 24 MPa, thereby delimiting the pressure in the piston rod side chamber 7 to that pressure.
  • the pressure delimiting member 16 is arranged so as to delimit the pressure in the piston rod side chamber 7 to approximately 24 MPa while the pressure in the cylinder side chamber reaches approximately 28 MPa during the continued piston rod displacement without aid of regenerative flow.
  • the maximum pressure drop over the pressure delimiting member 16 is equal to the minimum pressure accepted in the piston rod side chamber 7 upon ending of the regenerative operation.
  • a second embodiment according to which there is provided a pressure delimiting member 18 in the first conduit 10 between the direction valve 12 and the cylinder side chamber 6, instead of having a pressure delimiting member corresponding to member 16 in the second conduit 13.
  • the pressure delimiting member 18 is actuated at the moment when the pressure on the cylinder side has reached a value by which a pilot controlled valve 17 in the second conduit is opened for passage without pressure drop over it 13 and regenerative operation is ended.
  • the pressure in the cylinder side chamber 6 is reduced to a given value while the pressure in the piston rod side chamber 7 is reduced to generally the same pressure as in the reservoir 14 through activation of valve 17.
  • the pressure delimiting member 18 in fig. 3 is arranged in a fourth conduit 19 that in one end is connected to the first conduit 10 and in the other end is connected to low pressure reservoir 14, here via second conduit 13.
  • Pressure delimiting member 18 is arranged in series with a pilot-controlled valve 20, here an electrically controlled non-return valve arranged in the fourth conduit 19.
  • Valve 20 is actuated on for the opening thereof at the moment when a given pressure value has been reached on the cylinder side, regenerative operation is stopped, and when valve 17 in second conduit 13 is opened. There is no pressure drop over pilot controlled valve 20 when in its open state.
  • pressure fluid is drained via the fourth conduit 19 for the purpose of reducing the pressure in the cylinder side chamber 6.
  • the maximum pressure drop (in this example 14 MPa as indicated in the fig. 3) over the pressure delimiting member is equal to the maximum pressure accepted in the cylinder side chamber 6 upon opening of valve 17.
  • a delimited pressure difference between cylinder side and piston side is thereby guaranteed, and even though regenerative operation has been performed up to a high pressure on the cylinder side, full reduction or elimination of the pressure on piston rod side can be permitted without the risk of having a piston rod breakage.
  • Valves 17 and 20 in fig. 3 are both electrically controlled and activated upon receipt of a control signal emitted, upon a given pressure in cylinder side chamber 6, by a pressure gauge or sensor 21 arranged in the first conduit 10.
  • Pressure gauge 21 could deliver the control signal by wire or wireless and, possibly, via a control unit (not shown).
  • valves corresponding to valves 17 and 20 are hydraulically controlled and operated, are also within the scope of the invention.
  • a pressure delimiting member 22 is arranged in the first conduit 10 and comprises a counter pressure valve arranged for reduction of the pressure in the cylinder side chamber 6.
  • Pressure delimiting member 22 is arranged in parallel with an electrically operated non-return valve 28 which opens fully for flow towards the cylinder side chamber 6, without pressure drop over it, during regenerative operation.
  • Valve 28 is closed upon receipt of a control signal from a pressure gauge 21, as described for the embodiment offig. 3, once the pressure in the first conduit 10, or in the cylinder side chamber 6, has reached a predetermined value. Simultaneously, regenerative flow is ended, as valve 17 is or has just been opened for passage in second conduit 13 upon receipt of a control signal from said pressure gauge 21.
  • a pilot-controlled valve 23 here a non-return valve in the third conduit 15 for regenerative flow.
  • Said pilot controlled valve 23 upon actuation thereof, opens for regenerative flow of pressure fluid from piston rod side chamber 7 to cylinder side chamber 6.
  • a non-return valve 24 that prevents flow in the opposite direction, that is fromcylinder side chamber 6 to piston rod side chamber 7.
  • Valve 23 defines a means for breaking the regenerative operation, but all valves, that are essential for transition from regenerative to non-regenerative operation contribute to breaking the regenerative operation in one way or another.
  • the inventive device is still equipped with means for breaking the regenerative operation as this is a crucial feature of the device for the purpose of its functionality.
  • the third conduit 15 could be directly connected with, for example, the direction valve 12, and that the latter could then be equipped with a slide valve that would take the place and function of the regeneration valve 23 and the non-return valve in series therewith.
  • said sensing means includes a counter pressure valve 25 arranged in a forth conduit 26 that extends from the first conduit 10 to the reservoir via the second conduit 13.
  • the valve 25, which is a non-return valve, opens for flow towards the reservoir when the pressure in the first conduit 10 reaches a value (here 27 MPa) slightly lower than the maximum pressure that is still to be reached in the first conduit during regenerative operation (here 28 MPa).
  • Pilot controlled valve 17 is arranged to open fully, with no pressure drop thereover, as soon as a certain pressure (here1 MPa) has been reached in leakage conduit 27.
  • the opening of valve 17 is continuously, i.e. in a delayed mode, effectuated during pressure build up in conduit 27.
  • valve member 17 also defines a member for delaying thepressure transition from higher to lower pressure in the piston rod side chamber 7 upon termination of regenerative operation, which has proved itself to be an advantageous feature for the operation as a whole.
  • pilot controlled valve 17 in second conduit 13 and pilot controlled valve 18 in the fourth conduit 19 are controlled based on the pressure value measured by the pressure gauge 21.
  • pilot controlled valve 17 in second conduit 13 and pilot-controlled valve 22 in the first conduit 10 are controlled based on the pressure value measured or sensed by the pressure gauge 21.
  • the individual piston rod side chambers 7 are connected via a plurality of fifth conduits 30 that form part of the second conduit 13 and each of which is provided between two consecutive piston rod side chambers in the row of hydraulic units 2.
  • a piston rod side chamber 7 of a first hydraulic unit is connected via the second conduit 13 to the low pressure reservoir 14.
  • a sixth conduit 31 for regenerative conduction of pressure fluid from the piston rod side chamber 7 of one of the hydraulic units 2 to the cylinder side chamber 6 thereof.
  • a first end of the sixth conduit 31 is connected to the first conduit 10 and a second end thereof is connected to said fifth conduit 30.
  • the crane comprises means for controlling a flow of pressure fluid from the piston rod side chamber 7 via the fifth conduit 30 to the piston rod side chamber 7 of the adjacent hydraulic unit 2 or via the sixth conduit 31 to the cylinder side chamber 6 of the hydraulic unit 2 in question.
  • Said means comprises a valve member 32, 33 that is arranged to open for a flow through the sixth conduit 31 when a threshold value of the cylinder side chamber pressure is exceeded.
  • Valve member 32 comprises a pilot-controlled valve 32, here a non-return valve, that upon actuation will permit a regenerative flow towards the cylinder side chamber 6 in question. Actuation of valve 32 may be effected by, for example, the previously mentioned means 25, 26 for measuring and sensing the pressure in the first conduit 10.
  • Valve member 32 is arranged to open when the pressure difference between the cylinder side (conduit 10 or 31) and atmospheric pressure exceeds a pre-determined low value, here 1 MPa.
  • Valve member 32 may be a spring loaded valve, the spring of which is loaded by a leak flow of pressure fluid from the first conduit 10. Once the spring force is exceeded by the pressure fluid force, valve member 32 opens for regenerative flow through six conduit 31.
  • Means 34 defines a pressure delimiting member and comprises a restriction or throttle that upon sensing a pressure fall in the direction from the adjacent piston rod side chamber (which is closer to the low pressure reservoir in the row of piston rod side chamber in series) towards the rod side piston chamber 7 in question, actuates valve member 35 for permission of regenerative flow towards cylinder side chamber 6.
  • valve member 32 in order to permit regenerative flow, also valve member 32 must permit regenerative flow towards cylinder side chamber 6.
  • the crane comprises a number of elements the function of which are important for a reliable and effective operation of the crane. Accordingly there is a non-return valve 36 provided in parallel with the pressure delimiting member 17 in the second conduit, for allowing a flow of pressure fluid from the reservoir 14 towards the piston rod chambers 7 without throttling caused by the pressure delimiting member 17.
  • a non-return valve 37 is arranged in a corresponding way and for a corresponding purpose, in parallel with the sensing means 34.
  • non-return valves that normally permit the regenerative flow towards the cylinder side chamber 6 but prevent a flow in the opposite direction, are a natural part of any embodiment of the invention, in order to further improve the operation of the crane.
  • the invention comprises embodiments in which there is a pressure delimiting member in both the first and second conduit in order to permit an alternative in which the pressure is reduced in the first conduit as well asin the second conduit simultaneously.
  • pilot controlled valves can be used and that combinations of electrically controlled valves and hydraulically controlled valves are all within the scope of the invention, and that, therefore, combinations of the embodiments shown are within the scope of the invention.
  • the pressure in the reservoir 14 has been regarded as a reference pressure with the value zero (0), and all pressures mentioned in the pressure circuits presented above are given in relation to said reference value. In reality the pressure in the reservoir will most probably be equal to atmospheric pressure. Moreover the circuits described have been regarded as ideal in the meaning that no pressure drops along conduits etc. have been regarded. In reality, there will be such pressure drops.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Automation & Control Theory (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • General Engineering & Computer Science (AREA)
  • Fluid-Pressure Circuits (AREA)
EP03024717A 2003-10-29 2003-10-29 Kran und Methode zur Steuerung des Krans Withdrawn EP1528262A1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP03024717A EP1528262A1 (de) 2003-10-29 2003-10-29 Kran und Methode zur Steuerung des Krans

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP03024717A EP1528262A1 (de) 2003-10-29 2003-10-29 Kran und Methode zur Steuerung des Krans

Publications (1)

Publication Number Publication Date
EP1528262A1 true EP1528262A1 (de) 2005-05-04

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EP03024717A Withdrawn EP1528262A1 (de) 2003-10-29 2003-10-29 Kran und Methode zur Steuerung des Krans

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1406784A1 (de) * 1963-08-02 1969-04-17 Crede & Co Gmbh Geb Hubstapler mit hydraulischem Hubwerk
US4359931A (en) * 1981-01-19 1982-11-23 The Warner & Swasey Company Regenerative and anticavitation hydraulic system for an excavator
GB2159605A (en) * 1984-06-01 1985-12-04 Ming Chuan Shieh Regenerating reflux valve
DE3801007A1 (de) * 1988-01-15 1989-07-27 Joh Tirre Ohg Maschf Eilgangschaltung fuer einen schubzylinder, insbesondere fuer einen schubzylinder eines ladekranes
EP0481120A1 (de) * 1989-04-21 1992-04-22 KABUSHIKI KAISHA KOBE SEIKO SHO also known as Kobe Steel Ltd. Vorrichtung zur Unterdrückung von zitternden Bewegungen bei beweglichen Kränen
EP0482237A1 (de) * 1989-10-14 1992-04-29 KABUSHIKI KAISHA KOBE SEIKO SHO also known as Kobe Steel Ltd. Mechanismus zur Unterdrückung von Schwingungen bei beweglichen Kränen

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1406784A1 (de) * 1963-08-02 1969-04-17 Crede & Co Gmbh Geb Hubstapler mit hydraulischem Hubwerk
US4359931A (en) * 1981-01-19 1982-11-23 The Warner & Swasey Company Regenerative and anticavitation hydraulic system for an excavator
GB2159605A (en) * 1984-06-01 1985-12-04 Ming Chuan Shieh Regenerating reflux valve
DE3801007A1 (de) * 1988-01-15 1989-07-27 Joh Tirre Ohg Maschf Eilgangschaltung fuer einen schubzylinder, insbesondere fuer einen schubzylinder eines ladekranes
EP0481120A1 (de) * 1989-04-21 1992-04-22 KABUSHIKI KAISHA KOBE SEIKO SHO also known as Kobe Steel Ltd. Vorrichtung zur Unterdrückung von zitternden Bewegungen bei beweglichen Kränen
EP0482237A1 (de) * 1989-10-14 1992-04-29 KABUSHIKI KAISHA KOBE SEIKO SHO also known as Kobe Steel Ltd. Mechanismus zur Unterdrückung von Schwingungen bei beweglichen Kränen

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