EP2620405A1 - Structure de levage de grue à tour, système hydraulique de structure de levage et procédé de levage - Google Patents

Structure de levage de grue à tour, système hydraulique de structure de levage et procédé de levage Download PDF

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Publication number
EP2620405A1
EP2620405A1 EP11859735.0A EP11859735A EP2620405A1 EP 2620405 A1 EP2620405 A1 EP 2620405A1 EP 11859735 A EP11859735 A EP 11859735A EP 2620405 A1 EP2620405 A1 EP 2620405A1
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EP
European Patent Office
Prior art keywords
cylinders
working oil
lifting
hydraulic system
reversed
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
Application number
EP11859735.0A
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German (de)
English (en)
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EP2620405A4 (fr
EP2620405B1 (fr
Inventor
Yiliang Zhang
Shenglei HU
Sha LIANG
Bai LI
Kuai MAO
Mao WU
Yuli Li
Longjian CHEN
Hanlin ZHOU
Lekang YU
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Zoomlion Heavy Industry Science and Technology Co Ltd
Original Assignee
China Railway Major Bridge Engineering Co Ltd
Changsha Zoomlion Heavy Industry Science and Technology Development Co Ltd
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Publication of EP2620405A1 publication Critical patent/EP2620405A1/fr
Publication of EP2620405A4 publication Critical patent/EP2620405A4/fr
Application granted granted Critical
Publication of EP2620405B1 publication Critical patent/EP2620405B1/fr
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    • 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
    • B66C23/18—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 specially adapted for use in particular purposes
    • B66C23/26—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 specially adapted for use in particular purposes for use on building sites; constructed, e.g. with separable parts, to facilitate rapid assembly or dismantling, for operation at successively higher levels, for transport by road or rail
    • B66C23/28—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 specially adapted for use in particular purposes for use on building sites; constructed, e.g. with separable parts, to facilitate rapid assembly or dismantling, for operation at successively higher levels, for transport by road or rail constructed to operate at successively higher levels
    • B66C23/32—Self-hoisting cranes
    • 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
    • B66C23/18—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 specially adapted for use in particular purposes
    • B66C23/26—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 specially adapted for use in particular purposes for use on building sites; constructed, e.g. with separable parts, to facilitate rapid assembly or dismantling, for operation at successively higher levels, for transport by road or rail
    • B66C23/28—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 specially adapted for use in particular purposes for use on building sites; constructed, e.g. with separable parts, to facilitate rapid assembly or dismantling, for operation at successively higher levels, for transport by road or rail constructed to operate at successively higher levels
    • B66C23/283—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 specially adapted for use in particular purposes for use on building sites; constructed, e.g. with separable parts, to facilitate rapid assembly or dismantling, for operation at successively higher levels, for transport by road or rail constructed to operate at successively higher levels with frameworks composed of assembled elements

Definitions

  • the present invention relates to the crane domain, in particular to a lifting structure of tower crane, a hydraulic system for the lifting structure, and a lifting method of tower crane.
  • the object of the present invention is to provide a lifting structure of tower crane, a hydraulic system of the lifting structure, and a lifting method of tower crane, so as to solve the problem of out-of-sync lifting of tower cranes that employs two or more cylinders in the prior art.
  • the present invention provides a hydraulic system for lifting structure of tower crane, used to drive a climbing frame of the tower crane to ascend or descend on the tower body of tower crane, comprising a plurality of cylinders that are connected to lifting beams and upper beams of the tower crane respectively; wherein, each of the cylinders has a forward branch working oil circuit and a reversed branch working oil circuit; the forward branch working oil circuit of each cylinder has a forward speed regulator valve used to regulate the flow rate of hydraulic oil in the forward direction, and the reversed branch working oil circuit of each cylinder has a reversed speed regulator valve used to regulate the flow rate of hydraulic oil in the reversed direction.
  • the hydraulic system for lifting structure further comprises balancing valves arranged in each of the forward branch working oil circuits.
  • each of the balancing valves comprises an oil inlet, an oil outlet, and a control port, wherein, the oil inlet communicates with the forward branch working oil circuit, the oil outlet communicates with one of the rodless cavity and rod cavity of the cylinder, and the control port communicates with the reversed branch working oil circuit and another one of the rodless cavity and rod cavity of the cylinder.
  • the hydraulic system further comprises a main working oil circuit communicating with the forward branch working oil circuits and reversed branch working oil circuits respectively, and which has a pilot check valve communicating with the forward branch working oil circuits of the cylinders respectively, the pilot check valve has an opening ratio smaller than the opening ratio of each balancing valve.
  • the forward branch working oil circuit and reversed branch working oil circuit of each cylinder have a stop valve respectively.
  • the plurality of cylinders are connected in parallel to an oil tank, and the hydraulic system further comprises a main working oil circuit connected between the oil tank and the cylinders, which communicates with the forward branch working oil circuits and reversed branch working oil circuits, and the main working oil circuit has a combined valve comprising a combined reversing valve and a combined overflow valve, which communicate with each other.
  • the main working oil circuit has a back pressure valve connected in series to the oil tank, and which communicates with the reversed branch working oil circuits.
  • the main working oil circuit has an overflow valve, which communicates with the reversed branch working oil circuits.
  • the quantities of cylinders are six
  • the tower body has two sides, and one front and one back connected to the two sides, and two cylinders connected between the climbing frame and the lifting beams are arranged on each of the sides and the back of the tower body respectively.
  • the present invention further provides a lifting structure of tower crane, which comprises a tower body and a climbing frame arranged on the top of the tower body, wherein, the tower body has a step, the lifting beams are connected at the bottom to the upper beams, and the step support the lifting beams; the lifting structure further comprises a hydraulic system for lifting structure described above.
  • the present invention further provides a lifting method of tower crane, which is characterized in:arranging a plurality of cylinders connected between the upper beams and the lifting beams of the tower crane, controlling the forward and reversed flow rates of hydraulic oil in the branch working oil circuits of each cylinder and the accuracy of synchronization among the cylinders by means of a forward speed regulator valve and a reversed speed regulator valve on each of the cylinders, and controlling the cylinders to lift synchronously by maintaining the forward and reversed flow rates of hydraulic oil in the branch working oil circuits at the same value among the cylinders and controlling the cylinders to act synchronously.
  • two cylinders are arranged on two sides and a back of the climbing frame of tower crane, and each of the cylinders is connected between the upper beams and the lifting beams; the forward and reversed flow rates of hydraulic oil in the branch working oil circuits are maintained at the same value among the cylinders and the cylinders are controlled to act synchronously with the forward speed regulator valve and reversed speed regulator valve on each of the cylinders.
  • the weight of the lifting beams is balanced by means of a back pressure valve connected in series to an oil tank.
  • the climbing frame is prevented from falling in case of pressure loss in the cylinder by arranging a balancing valve on each of the cylinders to control the rodless cavity of the cylinder.
  • arranging a pilot check valve in the main working oil circuit of the hydraulic system and the opening ratio of the pilot check valve is smaller than the opening ratio of each of the balancing valves.
  • the forward and reversed flow rates of hydraulic oil in the branch working oil circuits of each cylinder and the accuracy of synchronization among the cylinders are controlled by means of the forward speed regulator valve and reversed speed regulator valve on each cylinder, and the cylinders are controlled to lift synchronously by maintaining the flow rates in the branch working oil circuits at the same value among the cylinders; in that way, the problem of out-of-sync lifting of cylinders on tower cranes in the prior art is solved, and the poor efficacy of synchronizing valves on tower cranes in the prior art can be solved.
  • hydraulic system of lifting structure drives a climbing frame 31 of tower crane to ascend and descend on the tower body 39 of the tower crane, for example, the climbing frame 31 is supported and driven by the hydraulic system to ascend and descend on the tower body 39 via guide pulleys 32 arranged on the tower body 39.
  • the hydraulic system comprises a plurality of cylinders 15; for example, two, three, four, six, or eight cylinders can be used, the cylinders 15 in such a quantity can be arranged more easily.
  • the hydraulic system comprises two cylinders 15, the two cylinders 15 can be arranged on one side or both sides of the climbing frame 31.
  • each cylinder 15 are connected to lifting beams 35 and upper beams 34 of the tower crane respectively, wherein, the upper beams 34 are fixed to the climbing frame 31, and the lifting beams 35 are fixed to the standard mast sections in a detachable manner, i.e., when the climbing frame 31 climbs, the lifting beams 35 are connected to the topmost standard mast section; when new standard mast section is added, the lifting beams 35 can be disconnected from the original standard mast section and then connected to the added standard mast section.
  • a clevis 33 can be utilized to support and locate the climbing frame 31, and thereby the position of the lifting beams 35 can be adjusted.
  • a step 37 are arranged on the tower body 39 of the tower crane. At the end of the lifting process, the step 37 will support and stop the lifting beams 35 to prevent the lifting beams 35 from moving again, and thereby ensure the safety of the tower crane.
  • the hydraulic system comprises six cylinders 15, which can have the same model and same structure.
  • each cylinder has a forward branch working oil circuit and a reversed branch working oil circuit, which are used to control the movement of rodless cavity and rod cavity of the cylinder 15 respectively.
  • the hydraulic system further comprises a main working oil circuit 21 that communicates with the forward branch working oil circuits and the reversed branch working oil circuits respectively.
  • the main working oil circuit 21 comprises a first main working oil circuit communicating with the forward branch working oil circuits and a second main working oil circuit communicating with the reversed branch working oil circuits.
  • each forward branch working oil circuit communicates with the rodless cavity of cylinder 15, and another one end of the forward branch working oil circuit communicates with an oil tank 1 of the hydraulic system via the first main working oil circuit;
  • one end of each reversed branch working oil circuit communicates with the rod cavity of cylinder 15, and another one end of the reversed branch working oil circuit communicates with the oil tank 1 of the hydraulic system via the second main working oil circuit.
  • a speed regulator valve 14 is arranged in the forward branch working oil circuit and reversed branch working oil circuit of each cylinder 15 respectively, wherein, the speed regulator valve 14 arranged in the forward branch working oil circuit is a forward speed regulator valve used to regulate the flow rate in the forward branch working oil circuit; the speed regulator valve 14 arranged in the reversed branch working oil circuit is a reversed speed regulator valve used to regulate the flow rate in the reversed branch working oil circuit.
  • the speed regulator valve 14 has precise scale, so as to control the flow rate of hydraulic oil in the working oil circuits accurately. It is understood that the forward branch working oil circuit will communicate with the rod cavity and the reversed branch working oil circuit will communicate with the rodless cavity when the piston rod of cylinder 15 is connected to the head beam 34 and the cylinder body is connected to the lifting beam 35.
  • the hydraulic system further comprises an oil pump 6 and a motor 7 driving the oil pump 6, wherein, the oil pump 6 is arranged in the main working oil circuit 21, one end of the oil pump 6 communicates with the oil tank 1, and anther end of the oil pump 6 communicates with both the forward branch working oil circuit and the reversed branch working oil circuit simultaneously.
  • the forward speed regulator valves on the six cylinders 15 are A11, A12, A13, A14, A15, and A16 respectively; the reversed speed regulator valves on the six cylinders 15 are B11, B12, B 13, B 14, B 15, and B16 respectively.
  • the extending and retracting speeds of each cylinder and the synchronization accuracy of the cylinders can be controlled respectively by controlling the opening of the speed regulator valve 14 in each branch to the same scale.
  • the forward branch working oil circuit of each cylinder 15 meets the first main working oil circuit of the main working oil circuit 21 at point A
  • the reversed branch working oil circuit of each cylinder 15 meets the second main working oil circuit of the main working oil circuit 21 at point B.
  • the speed regulator valve 14 has high speed rigidity, i.e., the flow rate is essentially immune to the impact of the load and the pressure fluctuation in the pump station once it is regulated to a specified value, the controlled flow rate will have no fluctuation essentially, and thereby the accuracy of synchronization among the cylinders 15 will be increased highly.
  • the forward and reversed flow rates of hydraulic oil in the branch working oil circuits of each cylinder 15 and the accuracy of synchronization among the cylinders 15 are controlled by means of the forward speed regulator valve and reversed speed regulator valve on each cylinder 15, and the cylinders 15 are controlled to lift synchronously by maintaining the synchronization of the working oil in eachbranch working oil circuits.
  • the problem of out-of-sync lifting of cylinders on tower cranes in the prior art is solved, and the poor efficacy of utilization of synchronizing valves in the prior art can be solved.
  • each cylinder 15 Owing to the fact that the ascending speed of the cylinders is different to the descending speed of the cylinders, a bridge rectifier synchronization circuit composed of a speed regulator valve and four check valves is not used; instead, each cylinder 15 employs two speed regulator valves to control the ascending speed and descending speed thereof respectively, so as to achieve the synchronization, i.e., six cylinders 15 employ 12 speed regulator valves altogether to achieve speed regulation and synchronization control.
  • the accumulative synchronous error during synchronous operation of the cylinders 15 can be eliminated by that the piston rods of the cylinders reach to the target positions.
  • the hydraulic system further comprises balancing valves 13 arranged in the forward branch working oil circuits.
  • Each of the balancing valves 13 comprises an oil inlet, an oil outlet, and a control port, wherein, the oil inlet communicates with the forward branch working oil circuit, the oil outlet communicates with one of the rodless cavity and rod cavity of the cylinder, and the control port communicates with the reversed branch working oil circuit and another one of the rodless cavity and rod cavity of the cylinder.
  • the oil inlet communicates with the forward branch working oil circuit
  • the oil outlet communicates with the rodless cavity of the cylinder
  • the control port communicates with the reversed branch working oil circuit and a rod control port in the rod cavity correspondingly.
  • the rod control port is arranged in the rod cavity of cylinder, and controls the pressure in the rodless cavity by means of the communication with the balancing valve 13, so as to reduce the idle work.
  • the six balancing valves 13 are arranged.
  • the balancing valve 13 will be closed, and thereby keep the cylinders at its position, so as to ensure safe operation of the tower crane.
  • the control port of balancing valve 13 communicates with the rod control port in the rod cavity, so as to regulate the working pressure in the rod cavity and reduce energy consumption.
  • a plurality of cylinders 15 are connection in parallel to one oil tank 1; in that way, the space can be save, and the weight of the tower crane can be reduced.
  • a back pressure valve 11 connected in series to the cylinders 15 is arranged in the second main working oil circuit of the main working oil circuit 21 of the hydraulic system, and the back pressure valve 11 communicates with each of the reversed branch working oil circuits and an oil pump 6 as well.
  • the back pressure valve 11 is mainly used to balance the weight of the lifting beams 35 on the end of the piston rods of the cylinders. Since the lifting beams 35 are connected on the piston rods of the cylinders 15, the heavy lifting beams 35 will tend to drive the piston rods to descend further due to inertia effect, and therefore have impact on the position accuracy of the pistons when the piston rods descend to a position and try to stop thereon. In this case, the system weight can be balanced, owing to the existence of the back pressure valve 11.
  • the hydraulic system further comprises a main working oil circuit 21, which communicates with the forward branch working oil circuits and the reversed branch working oil circuits respectively, and the main working oil circuit 21 has a combined valve 9 comprising a combined reversing valve and a combined overflow valve which communicate with each other.
  • the oil inlet of the combined valve 9 communicates with the oil pump 6, and the oil outlet of the combined valve 9 communicates with the forward branch working oil circuits and the reversed branch working oil circuits.
  • the hydraulic system further comprises an oil return circuit, through which the oil outlet of the combined valve 9, the forward branch working oil circuits and the reversed branch working oil circuits may communicate with the oil tank 1 directly.
  • the combined valve 9 is a group valve that integrates a plurality of valves.
  • the combined valve 9 is used to control the flow, reversal, and overflow of hydraulic oil in the main working oil circuit 21.
  • the combined reversing valve comprises check valves and reversing valves
  • the combined overflow valve comprises overflow valves.
  • the combined valve can be an off-the-shelf product, or can be assembled from check valves, reversing valves and overflow valves or other valves in the field. An off-the-shelf combined valve is preferred, so as to save installation time, furthermore, it is widely available in the market.
  • the hydraulic system further comprises a main working oil circuit 21, which communicates with the forward branch working oil circuits and the reversed branch working oil circuits respectively, and the main working oil has a pilot check valve 12 communicating with the forward branch working oil circuit of each cylinder 15 respectively, and which has an opening ratio smaller than the opening ratio of each balancing valve 13.
  • the pilot check valve 12 arranged in the first main working oil circuit communicating with the forward branch working oil circuit of each cylinder 15, thus, the hydraulic oil can only flow into the forward branch working oil circuits, but can't flow back when the tower crane lifts.
  • the opening ratio of the pilot check valve 12 is smaller than the opening ratio of each balancing valve 13, which is to say, the balancing valves 13 will open prior to the pilot check valve 12; thus, the startup error of the cylinders 15 can be reduced.
  • the pilot check valve 12 is arranged between the combined valve 9 and the forward branch working oil circuits.
  • pilot check valve 12 and balancing valves 13 another purpose of the pilot check valve 12 and balancing valves 13 is to force the oil to fill up all the pipelines extending from the pump station to the cylinders 15 (i.e., from the back pressure valve 11, pilot check valve 12, to the cylinders 15), so as to avoid air entrapment in the pipelines and thereby ensure stable and synchronous operation of the cylinders.
  • the forward branch working oil circuit and the reversed branch working oil circuit of each cylinder have a stop valve 16 respectively.
  • 12 stop valves 16 are arranged in the oil circuits of six cylinders 15.
  • the individual cylinders can be controlled to act separately, or several cylinders among the cylinders can be controlled in any combination to act in a coordinated manner.
  • the stop valves 16 can be closed, so that there will be no leakage in the working pipelines in that state.
  • the main working oil circuit 21 has an overflow valve, which communicates with the reversed branch working oil circuits and the oil tank 1.
  • the overflow valve 10 communicates with the rod cavity 15 of each cylinder 15 through the reversed branch working oil circuit, so as to reduce the pressure in the rod cavity of each cylinder 15, thus, the idle work and improve the energy efficiency of the entire system can be reduced.
  • the tower body has two sides, and one front and one back connected with the two sides, i.e., the tower body 39 has left side 391, right side 392, front introduction face 393, and back face 394; two cylinders 15 connected between the climbing frame 31 and the lifting beams 35 are arranged on each sides and the back face, but no cylinder 15 is arranged on the front introduction face 393 of the tower body, so that a preparation work for lifting can be done on the front introduction face 393 of the tower body; for example, some parts required for the lifting work can be introduced through the front introduction face 393.
  • Such arrangement is a three-face and six-cylinder lifting structure of tower crane.
  • such lifting structure comprises three lifting beams 35, six lifting cylinders 15, one hydraulic pump station 50, and hydraulic rubber tubes 17, etc.
  • Each two lifting cylinders 15 are connected to one lifting beam 35 and climbing frame 31 via pins, and each lifting cylinder 15 is connected to the hydraulic pump station 50 by hydraulic rubber tubes 17.
  • the three lifting beams 35 are arranged on the opposite face and sides face of the standard mast section introduction face respectively.
  • the cylinders 15 Under the control of the lifting hydraulic system, the cylinders 15 will operate synchronously and bear the same pressure in the lifting process of the tower crane, and operate stably, safely, and reliably in the mast section addition process for lifting and the mast section subtraction process for descending; moreover, every two cylinders 15 share a lifting beam 35, and the lifting force required in the lifting process is provided by six cylinders 15 respectively, which is to say, each lifting cylinder 15 only has to provide very low lifting force; thus, a common small-size lifting cylinders can be used, and therefore the cost and space can be reduced.
  • the present invention is not limited to the three-face and six-cylinder arrangement; for example, two cylinders or four cylinders can be arranged on the two sides, or three cylinders can be arranged on three sides.
  • the six cylinders 15 are controlled to ascend synchronously and bear the same pressure under the control of the hydraulic system.
  • the reversing lever When the cylinders lift synchronously to the target position, the reversing lever is switched to the right position of the combined valve 9, the hydraulic oil will flow freely through the back pressure valve 11, and be regulated by the speed regulator valves 14, and then flow into the respective rod cavities; at the same time, the control oil from the second main working oil circuit will open the pilot check valve 12 arranged in the first main working oil circuit; thus, the cylinders will support the climbing frame 31 to descend; in this process, the weight of the upper part of the tower crane is balanced by regulating the balancing valves 13, so that the climbing frame 31 will descend smoothly and steadily; after the clevis 33 are fit, the weight of the upper part of the tower crane will be supported by the clevis 33. Then, the piston rods of cylinders 15 will retract and carry the lifting beams 35 to release from the step on the tower body synchronously; then, the lifting beams 35 will ascend.
  • a vacant position for a standard mast section will occur between the lower support of the tower crane and the top of the standard mast sections, and the upper revolving part will be supported completely by the climbing frame 31.
  • a new standard mast section can be added between the top of the standard mast sections and the lower support, with the upper part of the added standard mast section connected to the lower support, and the lower part of the added standard mast section connected to the existing standard mast sections. The above procedure can be executed in the reversed sequence to reduce the mast height of the tower crane.
  • the hydraulic oil will be filtered by filter 2 and then transferred by high pressure pump 6 to the combined valve; after the control lever is switched to the left position, the hydraulic oil will flow freely through the check valve 12 and balancing valves 13 into the rodless cavities of the cylinders 15, and therefore the piston rods of the cylinders will extend and set the lifting beams connected to the top of the piston rods of cylinders synchronously into the step for the lower mast section of tower body; after the cylinders lift synchronously to the target position and the standard mast section subtraction operation is completed, the reversing lever is switched to the right position of the combined valve 9, and the hydraulic oil will flow freely through the back pressure valve 11, and be regulated by the speed regulator valves 14 synchronously, and then flow into the respective rod cavities; at the same time, the control oil from the right oil circuit will open the check valve 12 in the left oil circuit, and the cylinders will carry the climbing frame 31 to descend smoothly and steadily; then
  • the outlet pressure of the oil pump 50 is regulated by the combined valve 9, and is usually set to 1.15 times of the actual lifting pressure.
  • the working pressure of rod cavities of the cylinders is regulated by the overflow valve 10, which is lower than the set value of outlet pressure of the pump, so as to reduce energy consumption.
  • the present invention can maintain synchronization for multi-cylinders essentially.
  • the accuracy of synchronization for multi-cylinders mainly depends on the control accuracy of the speed regulator valves, and which is essentially immune to the impact of the balancing valves.

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  • Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Jib Cranes (AREA)
  • Fluid-Pressure Circuits (AREA)
EP11859735.0A 2011-03-02 2011-08-17 Structure de levage de grue à tour, système hydraulique de structure de levage et procédé de levage Not-in-force EP2620405B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN 201110050632 CN102173363B (zh) 2011-03-02 2011-03-02 塔式起重机的顶升结构及其液压系统和顶升方法
PCT/CN2011/078540 WO2012116537A1 (fr) 2011-03-02 2011-08-17 Structure de levage de grue à tour, système hydraulique de structure de levage et procédé de levage

Publications (3)

Publication Number Publication Date
EP2620405A1 true EP2620405A1 (fr) 2013-07-31
EP2620405A4 EP2620405A4 (fr) 2014-04-16
EP2620405B1 EP2620405B1 (fr) 2015-10-14

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EP11859735.0A Not-in-force EP2620405B1 (fr) 2011-03-02 2011-08-17 Structure de levage de grue à tour, système hydraulique de structure de levage et procédé de levage

Country Status (3)

Country Link
EP (1) EP2620405B1 (fr)
CN (1) CN102173363B (fr)
WO (1) WO2012116537A1 (fr)

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CN103626047A (zh) * 2013-09-09 2014-03-12 胡江 船用伸缩起重机
CN103663183A (zh) * 2013-11-29 2014-03-26 江苏大通重工有限公司 快速自安装塔式起重机
CN105417429A (zh) * 2015-12-22 2016-03-23 中联重科股份有限公司 配重提升装置及具有其的起重机

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CN102505630A (zh) * 2011-11-17 2012-06-20 廊坊凯博建设机械科技有限公司 桥梁检测作业车双油缸同步系统
CN102491186A (zh) * 2011-12-19 2012-06-13 中联重科股份有限公司 塔式起重机
CN103303811A (zh) * 2013-06-13 2013-09-18 山东丰汇设备技术有限公司 内爬塔机自动顶升系统
CN105438989B (zh) * 2014-12-19 2018-02-16 徐州重型机械有限公司 起重机上下车供油系统
CN104528582A (zh) * 2014-12-26 2015-04-22 柳州欧维姆机械股份有限公司 智能分控式液压同步顶升系统及其用于桥梁支座更换的方法
CN105129608A (zh) * 2015-06-12 2015-12-09 焦作大学 一种集装箱起重机加高装置
CN105271014A (zh) * 2015-09-30 2016-01-27 徐州建机工程机械有限公司 一种塔机可拆式套架结构
CN105174062B (zh) * 2015-10-19 2017-04-19 中联重科股份有限公司 一种多油缸顶升同步控制系统、方法、装置及塔式起重机
CN105480876A (zh) * 2016-01-04 2016-04-13 徐州建机工程机械有限公司 一种塔式起重机内顶升机构
CN106762883B (zh) * 2016-12-30 2018-07-13 中联重科股份有限公司 液压系统及塔机
CN109368498B (zh) * 2018-08-09 2020-06-09 青岛理工大学 一种基于bim智能装配式节点构造与建造的自动化系统
CN110206155B (zh) * 2019-05-31 2021-06-15 浙江精工钢结构集团有限公司 一种底部加节液压顶升系统及施工方法
CN113264459A (zh) * 2021-05-31 2021-08-17 湖南三一塔式起重机械有限公司 塔式起重机及其顶升配平方法
CN113955653A (zh) * 2021-10-11 2022-01-21 中联重科建筑机械(江苏)有限责任公司 自爬升式塔机及其多缸顶升系统
CN115490164A (zh) * 2022-09-22 2022-12-20 徐州建机工程机械有限公司 一种塔机爬升过程防脱结构、防脱方法及塔机

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2253201A1 (de) * 1972-10-30 1974-05-09 Jul Wolff & Co Gmbh Vorrichtung zum hochheben des oberteils eines turmkranes oder dergleichen kranes von seinem unterteil
EP0516938A1 (fr) * 1991-06-04 1992-12-09 Liebherr-Werk Biberach GmbH Dispositif pour soulever par étapes des charges lourdes pour grues pivotantes sur pylone ou plateformes de travail
DE202005009236U1 (de) * 2005-05-09 2006-09-21 Liebherr-Werk Biberach Gmbh Kletteinrichtung für einen Turmdrehkran

Family Cites Families (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4274542A (en) * 1979-02-26 1981-06-23 Fmc Corporation Method for transfer of crane from tower
JP2809308B2 (ja) * 1988-05-09 1998-10-08 越原 良忠 建設用タワークレーンのジブ起伏速度制御装置
JP3504369B2 (ja) * 1995-03-13 2004-03-08 石川島播磨重工業株式会社 タワークレーン
CN2333687Y (zh) * 1998-06-03 1999-08-18 胡建锋 内爬塔式起重机爬升机构
CN2466125Y (zh) * 2001-02-28 2001-12-19 长沙中联重工科技发展股份有限公司 自升式内爬顶升系统
CN2488893Y (zh) * 2001-08-10 2002-05-01 王震山 塔机液压顶升装置
CN2679123Y (zh) * 2002-12-19 2005-02-16 胡建锋 新型内爬塔式起重机
CN2658453Y (zh) * 2003-11-21 2004-11-24 谢彬 新型塔式起重机液压顶升泵站
CN201225344Y (zh) * 2008-05-20 2009-04-22 上海建工（集团）总公司 建筑施工爬模顶升同步控制系统
CN201288033Y (zh) * 2008-08-28 2009-08-12 中国二十冶建设有限公司 八点液压同步顶升设备的控制装置
CN201334318Y (zh) * 2008-12-25 2009-10-28 张恕铭 一种塔机升降装置
CN201495049U (zh) * 2009-09-29 2010-06-02 四川建设机械（集团）股份有限公司 塔式起重机顶升动力机构
CN101759106B (zh) * 2009-12-29 2012-07-25 中联重科股份有限公司 塔式起重机顶升油缸和上横梁的连接结构及连接方法
CN202016806U (zh) * 2011-03-02 2011-10-26 长沙中联重工科技发展股份有限公司 塔式起重机的顶升结构及其液压系统

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2253201A1 (de) * 1972-10-30 1974-05-09 Jul Wolff & Co Gmbh Vorrichtung zum hochheben des oberteils eines turmkranes oder dergleichen kranes von seinem unterteil
EP0516938A1 (fr) * 1991-06-04 1992-12-09 Liebherr-Werk Biberach GmbH Dispositif pour soulever par étapes des charges lourdes pour grues pivotantes sur pylone ou plateformes de travail
DE202005009236U1 (de) * 2005-05-09 2006-09-21 Liebherr-Werk Biberach Gmbh Kletteinrichtung für einen Turmdrehkran

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of WO2012116537A1 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103626047A (zh) * 2013-09-09 2014-03-12 胡江 船用伸缩起重机
CN103663183A (zh) * 2013-11-29 2014-03-26 江苏大通重工有限公司 快速自安装塔式起重机
CN105417429A (zh) * 2015-12-22 2016-03-23 中联重科股份有限公司 配重提升装置及具有其的起重机

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CN102173363B (zh) 2013-09-18
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EP2620405A4 (fr) 2014-04-16
EP2620405B1 (fr) 2015-10-14

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