Tower crane jacking device and hydraulic control system

Abstract

This invention belongs to the technical field of tower cranes, specifically relating to a tower crane lifting device and hydraulic control system. The tower crane lifting device includes a lifting frame, a lifting cylinder, and an auxiliary cylinder. One end of the lifting cylinder is hinged to the middle of the frame beam on the lifting frame, and the other end is hinged to the middle of the lifting beam. Both ends of the lifting beam are equipped with lifting beam pawls. One end of the auxiliary cylinder is hinged to the cylinder barrel of the lifting cylinder, and the other end is hinged to the middle of an auxiliary tilting beam. Both ends of the auxiliary tilting beam are equipped with frame beam pawls, which are rotatably connected to the lifting frame. This invention employs a hydraulically controlled auxiliary positioning system, which is structurally and hydraulically integrated with the tower crane's lifting hydraulic system, meeting the operational requirements for tower crane lifting and lowering, as well as the auxiliary positioning of the lifting beam pawls, frame beam pawls, and standard section steps.

Description

Technical Field

[0001] This invention belongs to the field of tower crane technology, specifically relating to a tower crane lifting device and hydraulic control system. Background Technology

[0002] Tower cranes involve continuously adding or removing standard sections during their self-lifting process. This requires the lifting beam and its pawls connected below the lifting cylinder, and the sleeve beam and its pawls connected above the lifting cylinder, to be alternately engaged with the standard section steps, forming a load-bearing structure to complete the gradual ascent or descent of the tower crane's lifting frame. In the industry, the engagement of the lifting beam pawls and sleeve beam pawls with the standard section steps is generally done manually, either by direct manual pushing or by converting mechanical structures into manual pushing. This is quite laborious, and the lifting beam pawls on the lifting beam are located below the lifting system's working platform, while the sleeve beam pawls or outriggers on the sleeve beam are located above the platform and are separate, requiring multiple operators. Especially for large-tonnage tower cranes, the lifting beams and their pawls, as well as the sleeve beams and their pawls, are larger and heavier, requiring more operators and more frequent operations.

[0003] Existing technologies also include adding auxiliary mechanisms to achieve the lifting beam pawl and the attachment of the frame beam pawl to the standard section steps. For example, Chinese patent document CN216129250U discloses a hydraulic cylinder moving auxiliary structure and a tower crane. The hydraulic cylinder moving auxiliary structure includes a support assembly; a thrust plate with a connecting hole, through which the thrust plate is rotatably connected to the support assembly; a thrust rod assembly connected to the first end of the thrust plate; and a roller assembly connected to the second end of the thrust plate, which abuts against the hydraulic cylinder. The distance between the end of the thrust rod assembly furthest from the thrust plate and the center of the connecting hole is greater than the distance between the roller assembly and the center of the connecting hole. This device utilizes the lever principle in designing the hydraulic cylinder moving auxiliary structure, making operation easier for the operator. Furthermore, the rollers create rolling friction between the rollers and the hydraulic cylinder, reducing friction and further reducing operator effort. It also minimizes damage to the hydraulic cylinder caused by the pushing component.

[0004] The technical solutions disclosed in the aforementioned Chinese patent documents have the following drawbacks or deficiencies:

[0005] (1) The structure uses the lever principle and is manually driven to push the auxiliary structure, which in turn drives the tower crane lifting hydraulic cylinder and the lifting beam connected to the rodless chamber of the lifting hydraulic cylinder to move horizontally together. This patented structure is manually operated, which is labor-intensive and has limited output force.

[0006] (2) It can be seen that its structure is a moving auxiliary structure for the lifting beam, and does not involve the frame beam, nor does it integrate the lifting beam and the frame beam design.

[0007] (3) Its auxiliary structure is located near the end of the piston rod of the lifting cylinder. The closer it is to the end of the piston rod, the greater the rotation radius of the lifting cylinder, and the less effort is required. However, as can be seen from the industry tower cranes, the end near the piston rod is definitely not on the same platform as the lifting system operating platform. Therefore, the auxiliary structure is not convenient enough. Summary of the Invention

[0008] To overcome the shortcomings of the prior art, the present invention provides a tower crane jacking device and hydraulic control system, which adopts a hydraulically controlled auxiliary positioning system. This auxiliary positioning system is integrated with the tower crane's jacking hydraulic system in terms of structure and hydraulic principle, meeting the working requirements of tower crane jacking and lowering, as well as the auxiliary positioning of the jacking beam pawl, the sleeve beam pawl and the standard section steps.

[0009] This invention is achieved through the following technical solution: a tower crane lifting device, comprising:

[0010] Lifting frame;

[0011] The lifting cylinder has one end hinged to the middle of the upper frame crossbeam of the lifting sleeve, and the other end hinged to the middle of the lifting crossbeam. Both ends of the lifting crossbeam are equipped with lifting crossbeam pawls.

[0012] An auxiliary hydraulic cylinder is hinged at one end to the cylinder of the lifting hydraulic cylinder and at the other end to the middle of the auxiliary tilting crossbeam. Both ends of the auxiliary tilting crossbeam are respectively provided with a sleeve crossbeam pawl, and the sleeve crossbeam pawl is rotatably connected to the lifting sleeve.

[0013] In some embodiments, the bottom of the lifting cylinder is hinged to the sleeve crossbeam, and the piston rod of the lifting cylinder is hinged to the lifting crossbeam.

[0014] In some embodiments, the auxiliary flipping beam and the pawl of the sleeve beam are fixed by bolts.

[0015] In some embodiments, the frame beam is provided with a lifting beam guardrail to protect the lifting beam.

[0016] The present invention also provides a hydraulic control system, including an operating control valve group and a tower crane lifting device as described above;

[0017] The operation control valve group includes a first reversing valve, a second reversing valve, and a third reversing valve;

[0018] The oil inlet of the first directional valve is connected to the oil supply circuit, the first working oil port of the first directional valve is connected to the oil inlet of the second directional valve, and the second working oil port of the first directional valve is connected to the oil inlet of the third directional valve.

[0019] The first working port of the second reversing valve is connected to the rodless chamber of the lifting cylinder in the tower crane lifting device, and the second working port of the second reversing valve is connected to the rod chamber of the lifting cylinder.

[0020] The first working port of the third directional valve is connected to the rodless chamber of the auxiliary cylinder in the tower crane lifting device, and the second working port of the third directional valve is connected to the rod chamber of the auxiliary cylinder.

[0021] In some embodiments, a bidirectional balance valve is provided between the first working port of the second directional valve, the second working port of the second directional valve, and the lifting cylinder.

[0022] In some embodiments, a superimposed one-way throttle valve is provided between the third directional valve and the auxiliary cylinder.

[0023] In some embodiments, the first reversing valve, the second reversing valve, and the third reversing valve are all manually operated valves.

[0024] The beneficial effects of the present invention are: (1) The lifting cylinder and the auxiliary cylinder are integrated into a telescopic and flipping hybrid linkage mechanism composed of the lifting cylinder, the lifting beam, the auxiliary cylinder and the auxiliary flipping beam, so as to realize the flipping of the auxiliary flipping beam and the flipping of the lifting beam, as well as the up and down movement of the lifting beam.

[0025] (2) The hydraulic system is integrated with jacking and auxiliary positioning control circuits to achieve integrated control of the jacking cylinder and auxiliary cylinder. The hydraulic system consists of a jacking hydraulic system pump station, an operating control valve group, jacking cylinders, and auxiliary cylinders. The operating control valve group consists of a relief valve, a check valve, a pressure gauge, a first directional valve, a second directional valve, a third directional valve, a stacked relief valve, and a stacked one-way throttle valve. It realizes the hydraulic integrated control principle of tower crane jacking and descent, assisted positioning of the frame beam and frame beam pawl, and assisted positioning of the jacking beam and jacking beam pawl, and has the functions of load balancing and locking, auxiliary positioning speed control, and auxiliary locking.

[0026] (3) The operation of the jacking hydraulic system pump station and auxiliary cylinder is located on the same working platform, making operation observation and installation and maintenance more convenient. Attached Figure Description

[0027] Figure 1 This is a simplified structural diagram of the present invention;

[0028] Figure 2 This is a schematic diagram of the invention applied to a tower crane;

[0029] Figure 3 This is a schematic diagram of the hydraulic control system of the present invention;

[0030] In the diagram, 1. Tower crane standard section; 2. Lifting frame; 3. Lifting beam; 4. Lifting cylinder; 5. Auxiliary cylinder; 6. Lifting hydraulic system pump station; 7. Auxiliary tilting beam; 8. Frame beam pawl; 9. Lifting beam pawl; 10. Standard section steps; 11. Lifting beam guardrail; 12. Frame beam; 100. Operating control valve group; 2.1. Relief valve; 2.2. Check valve; 2.3. Pressure gauge; 2.4. First directional valve; 2.5. Second directional valve; 2.6. Third directional valve; 2.7. Stacked relief valve; 2.8. Stacked one-way throttle valve. Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] like Figure 1 and Figure 2 As shown, a tower crane lifting device includes a lifting frame 2, a lifting cylinder 4, and an auxiliary cylinder 5. The lifting frame 2 serves as the basic component of the lifting device.

[0033] The bottom of the lifting cylinder 4 is hinged to the middle of the frame beam 12 on the lifting sleeve 2 via a pin. The piston rod of the lifting cylinder 4 is hinged to the middle of the lifting beam 3 via a pin. Lifting beam pawls 9 are respectively provided at both ends of the lifting beam 3.

[0034] The cylinder of the lifting cylinder 4 is provided with a lug plate for connecting the auxiliary cylinder 5. The bottom of the auxiliary cylinder 5 is hinged to the cylinder of the lifting cylinder 4 by a pin. The piston rod of the lifting cylinder 4 is hinged to the middle of the auxiliary tilting beam 7 by a pin. The two ends of the auxiliary tilting beam 7 are respectively provided with a sleeve beam pawl 8. The auxiliary tilting beam 7 and the sleeve beam pawl 8 are fixed by bolts. The sleeve beam pawl 8 is rotatably connected to the lifting sleeve 2 by a pin.

[0035] The above technical solution consists of a telescopic and tilting hybrid linkage mechanism composed of a lifting cylinder 4, a lifting crossbeam 3, an auxiliary cylinder 5, and an auxiliary tilting crossbeam 7, which realizes the tilting of the auxiliary tilting crossbeam 7 and the tilting of the lifting crossbeam 3, as well as the up and down movement of the lifting crossbeam 3.

[0036] Auxiliary tilting beam 7 tilting: When the lifting beam pawls 9 on both sides of the lifting beam 3 are engaged with the standard section steps 10 on the standard section 1 of the tower crane, and the sleeve beam pawls 8 on both sides of the auxiliary tilting beam 7 are misaligned with the standard section steps 10 (the standard section steps 10 are long blocks, vertically welded to the standard section 1 of the tower crane, and both the upper and lower ends of the standard section steps 10 are equipped with U-shaped slots; the sleeve beam pawls 9 are engaged in the slots of the standard section steps 10 to achieve the desired tilting effect). When step 10 is engaged, the auxiliary hydraulic cylinder 5, during its extension and retraction, cannot drive the auxiliary tilting beam 7 to rotate the sleeve beam pawl 9. Only when the sleeve beam pawl 9 is disengaged from the standard section step 10 can the auxiliary hydraulic cylinder 5 drive the sleeve beam pawl 9 to rotate along with the auxiliary tilting beam 7. When the auxiliary hydraulic cylinder 5 extends and retracts, the auxiliary tilting beam 7 and the sleeve beam pawl 8 will rotate around the hinge point between the auxiliary hydraulic cylinder 5 and the auxiliary tilting beam 7. The auxiliary hydraulic cylinder 5 and the auxiliary tilting beam 7 form an upper tilting mechanism, which enables the sleeve beam pawl 8 to engage or disengage from the standard section step 10.

[0037] Lifting beam 3 tilting: When the pawls 8 of the auxiliary tilting beam 7 on both sides are engaged with the standard section steps 10 on the standard section 1 of the tower crane, and the pawls 9 of the lifting beam 3 on both sides are misaligned with the standard section steps 10 (the working principle of this misalignment is the same as that of the pawls 8 of the auxiliary tilting beam and the standard section steps 10), the auxiliary cylinder 5 performs a telescopic action, and the lifting cylinder 4 and the lifting beam 3 will rotate around the hinge point between the lifting cylinder 4 and the auxiliary tilting beam 12. The lifting cylinder 4 and the lifting beam 3 form a downward tilting mechanism, which enables the pawls 9 of the lifting beam to engage or disengage from the standard section steps 10.

[0038] Based on the above technical solution, the working principle of this invention is as follows: When the lifting frame 2 needs to be lifted (i.e., when the tower crane adds a standard tower crane section), the piston rod of the lifting cylinder 4 before lifting is in a retracted state, and the lifting beam pawl 9 and the standard section step 10 are in an engaged state, while the frame crossbeam pawl 8 and the standard section step 10 are in a disengaged state. The piston rod of the lifting cylinder 4 extends, using the lifting beam pawl 9 and the lifting beam 3 as support points to lift the lifting frame 2 upwards. After the lifting frame 2 is lifted into place, the auxiliary cylinder 5 is operated to make the frame crossbeam pawl 8 and the standard section step 10 enter the engaged state. Then, through the action of the auxiliary cylinder 5, the lifting beam pawl 9 and the standard section step 10 are disengaged. Retract the piston rod of the lifting cylinder 4, and operate the auxiliary cylinder 5 again to engage the lifting beam pawl 9 with the standard section step 10, while disengaging the sleeve beam pawl 8 from the standard section step 10. Await the next lifting operation.

[0039] When the lifting frame 2 needs to be lowered (i.e., when the tower crane is being lowered by removing a standard section), before lowering, the control frame crossbeam pawl 8 and standard section step 10 are engaged, while the lifting crossbeam pawl 9 and standard section step 10 are disengaged. The piston rod of the retracted lifting cylinder 4 is then extended. Once the piston rod of the lifting cylinder 4 is fully extended, the lifting crossbeam pawl 9 and standard section step 10 are engaged. Then, the frame crossbeam pawl 8 and standard section step 10 are disengaged, and the piston rod of the lifting cylinder 4 is retracted to lower the lifting frame 2. Repeating the above actions completes the tower crane dismantling operation.

[0040] The lifting beam 3 moves up and down: the piston rod of the lifting cylinder 4 extends and retracts, driving the lifting beam 3 to move up and down.

[0041] In some embodiments, the frame beam 12 is provided with a lifting beam guardrail 11 to protect the lifting beam 3.

[0042] like Figure 3 As shown, the present invention also provides a hydraulic control system, including an operating control valve group 100 and a tower crane lifting device as described above.

[0043] The operation control valve group 100 includes a first reversing valve 2.4, a second reversing valve 2.5, and a third reversing valve 2.6, all of which are three-position four-way manual operation valves.

[0044] The inlet of the first directional valve 2.4 is connected to the oil supply circuit, and the return port of the first directional valve 2.4 is connected to the oil return circuit. Specifically, the inlet and return ports of the first directional valve 2.4 are connected to the lifting hydraulic system pump station 6 installed on the platform. The first working port of the first directional valve 2.4 is connected to the inlet of the second directional valve 2.5, and the second working port of the first directional valve 2.4 is connected to the inlet of the third directional valve 2.6.

[0045] The first working port of the second reversing valve 2.5 is connected to the rodless chamber of the lifting cylinder 4 in the tower crane lifting device, and the second working port of the second reversing valve 2.5 is connected to the rod chamber of the lifting cylinder 4.

[0046] The first working port of the third directional valve 2.6 is connected to the rodless chamber of the auxiliary cylinder 5 in the tower crane lifting device, and the second working port of the third directional valve 2.6 is connected to the rod chamber of the auxiliary cylinder 5.

[0047] When the first directional valve 2.4 is in the left position, the hydraulic control system is used to lift the cylinder 4; when the first directional valve 2.4 is in the right position, the hydraulic control system is used to assist the cylinder 5.

[0048] When the second directional valve 2.5 is in the left position, its inlet port is connected to its first working port, and its second working port is connected to its return port. When the second directional valve 2.5 is in the right position, its inlet port is connected to its second working port, and its first working port is connected to its return port.

[0049] When the third directional valve 2.6 is in the left position, its inlet port is connected to its first working port, and its second working port is connected to its return port. When the third directional valve 2.6 is in the right position, its inlet port is connected to its second working port, and its first working port is connected to its return port.

[0050] Based on the above hydraulic control system, the control principle of this invention is as follows:

[0051] Assisted positioning of the frame beam 12: With the lifting beam pawls 9 on both sides of the lifting beam 3 engaged in the standard section step 10 on the tower crane's standard section 1, the following steps are performed: 1. Operate the first directional valve 2.4 to the right position, then operate the third directional valve 2.6 to the left position. Hydraulic oil enters the rodless chamber of the auxiliary cylinder 5, extending the auxiliary cylinder 5. This causes the auxiliary tilting beam 7 and the frame beam pawls 8 to rotate around the hinge point between the auxiliary cylinder 5 and the auxiliary tilting beam 7 towards the inside of the lifting frame 2, until the frame beam pawls 8 are pressed against the standard section step 10. 2. Operate the first directional valve 2.4 to the left position, then operate the second directional valve 2.5 to the right position. Hydraulic oil enters the rod chamber of the lifting cylinder 4, causing the piston rod of the lifting cylinder 4 to retract, until the frame beam pawls 8 are engaged in the standard section step 10, completing the assisted positioning of the frame beam 12.

[0052] When the lifting frame 2 needs to be lifted, the lifting beam 3 assists in positioning: With the pawls 8 of the lifting frame beam on both sides of the auxiliary tilting beam 7 engaged with the standard section steps 10 on the tower crane standard section 1, the following steps are performed: 1. Operate the first reversing valve 2.4 to the left position and operate the second reversing valve 2.5 to the right position to retract the piston rod of the lifting cylinder 4 a certain distance, thereby disengaging the lifting beam pawls 9 from the standard section steps 10. 2. Switch the first reversing valve 2.4 to the right position and operate the third reversing valve 2.6 to the right position to retract the auxiliary cylinder 5. At this time, since the pawls 8 of the lifting frame beam are engaged within the standard section steps 10, the lifting cylinder 4 drives the lifting beam 3 and the lifting beam pawls 9 to tilt outwards around the hinge point between the lifting beam 3 and the lifting frame beam 12, completely disengaging the lifting beam pawls 9 from the standard section steps 10. III. Switch the first directional valve 2.4 to the left position and operate the second directional valve 2.5 to the right position to retract the piston rod of the lifting cylinder 4 until the lifting beam 3 and the lifting beam pawl 9 reach the next standard section step 10. IV. Switch the first directional valve 2.4 to the right position and operate the third directional valve 2.6 to the left position to extend the auxiliary cylinder 5. Since the sleeve beam pawl 8 is engaged in the standard section step 10, the lifting cylinder 4 drives the lifting beam 3 and the lifting beam pawl 9 to rotate around the hinge point between the lifting beam 3 and the sleeve beam 12 towards the inside of the lifting sleeve 2, so that the lifting beam pawl 9 is close to the standard section step 10. V. Switch the first directional valve 2.4 to the left position and operate the second directional valve 2.5 to extend the piston rod of the lifting cylinder 4 until the lifting beam pawl 9 is fully engaged in the standard section step 10, completing the auxiliary positioning of the lifting beam 3.

[0053] When the lifting frame 2 needs to be lowered, the basic working principle of the lifting beam 3 assisting in positioning is similar to the working principle of the lifting beam 3 assisting in positioning when the lifting frame 2 needs to be lifted. Those skilled in the art can implement this operation by combining the above technical solutions, and it will not be described here.

[0054] To ensure the stable operation of the hydraulic control system, in some embodiments, a two-way balance valve is provided between the first working port of the second directional valve 2.5, the second working port of the second directional valve 2.5, and the lifting cylinder 4. The design of the two-way balance valve realizes load balance and locking during the heavy-load lifting of the frame 2 and the unloaded lifting of the lifting beam 3, preventing stalling or cylinder slippage, ensuring safety and reliability. A superimposed one-way throttle valve 2.8 is provided between the third directional valve 2.6 and the auxiliary cylinder 5. The design of the superimposed one-way throttle valve 2.8 has two functions: First, it can adjust the inlet and outlet oil flow of the auxiliary cylinder 5 and control the operating speed of the auxiliary cylinder 5. Second, when the lifting cylinder 4 is activated, the auxiliary cylinder 5 is not activated. At this time, the superimposed one-way throttle valve 2.8 is closed, realizing the locking of the auxiliary cylinder 5, preventing the auxiliary cylinder 5 from sliding down due to leakage in the middle position of the directional valve, and meeting the requirements of the auxiliary tilting beam positioning operation. The operating control valve group 100 also includes a relief valve 2.1, a check valve 2.2 that unidirectionally connects the lifting hydraulic system pump station 6 to the oil inlet of the first directional valve 2.4, a pressure gauge 2.3 that monitors the pressure of the hydraulic control system, and a stacked relief valve 2.7 located at the first working oil port of the third directional valve 2.6 and the second working oil port of the third directional valve 2.6. The stacked relief valve 2.7 provides safety protection during lifting and auxiliary operations.

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall fall within the scope of the technical solution of the present invention.

Claims

1. A tower crane lifting device, characterized in that, include: Lifting frame (2); The lifting cylinder (4) has one end hinged to the middle of the upper frame crossbeam (12) of the lifting sleeve (2), and the other end hinged to the middle of the lifting crossbeam (3). Both ends of the lifting crossbeam (3) are respectively equipped with lifting crossbeam pawls (9); and The auxiliary cylinder (5) is hinged at one end to the cylinder of the lifting cylinder (4) and at the other end to the middle of the auxiliary tilting beam (7). The two ends of the auxiliary tilting beam (7) are respectively provided with a frame beam pawl (8), and the frame beam pawl (8) is rotatably connected to the lifting frame (2). When the lifting beam pawls (9) on both sides of the lifting beam (3) are engaged with the standard section steps (10) on the standard section (1) of the tower crane, and the pawls (8) on both sides of the auxiliary tilting beam (7) are misaligned with the standard section steps (10), the auxiliary cylinder (5) performs a telescopic action, and the auxiliary tilting beam (7) and the pawls (8) on the pawls will rotate around the hinge point between the auxiliary cylinder (5) and the auxiliary tilting beam (7). When the pawls (8) of the frame beam on both sides of the auxiliary tilting beam (7) are engaged with the standard section steps (10) on the standard section (1) of the tower crane, and the pawls (9) of the lifting beam on both sides of the lifting beam (3) are misaligned with the standard section steps (10), the auxiliary cylinder 5 performs a telescopic action, and the lifting cylinder (4) and the lifting beam (3) will rotate around the hinge point between the lifting cylinder (4) and the frame beam (12).

2. The tower crane lifting device according to claim 1, characterized in that: The bottom of the lifting cylinder (4) is hinged to the frame beam (12), and the piston rod of the lifting cylinder (4) is hinged to the lifting beam (3).

3. The tower crane lifting device according to claim 1, characterized in that: The auxiliary flipping beam (7) and the pawl (8) of the sleeve beam are fixed by bolts.

4. The tower crane lifting device according to claim 1, characterized in that: The frame beam (12) is provided with a lifting beam guardrail (11) to protect the lifting beam (3).

5. A hydraulic control system, characterized in that: Includes an operating control valve assembly (100) and a tower crane lifting device as described in any one of claims 1 to 4; The operation control valve group (100) includes a first directional valve (2.4), a second directional valve (2.5), and a third directional valve (2.6). The oil inlet of the first directional valve (2.4) is connected to the oil supply circuit, the first working oil port of the first directional valve (2.4) is connected to the oil inlet of the second directional valve (2.5), and the second working oil port of the first directional valve (2.4) is connected to the oil inlet of the third directional valve (2.6). The first working port of the second reversing valve (2.5) is connected to the rodless chamber of the lifting cylinder (4) in the tower crane lifting device, and the second working port of the second reversing valve (2.5) is connected to the rod chamber of the lifting cylinder (4). The first working port of the third directional valve (2.6) is connected to the rodless chamber of the auxiliary cylinder (5) in the tower crane lifting device, and the second working port of the third directional valve (2.6) is connected to the rod chamber of the auxiliary cylinder (5).

6. The hydraulic control system according to claim 5, characterized in that: A two-way balance valve is provided between the first working port of the second reversing valve (2.5), the second working port of the second reversing valve (2.5), and the lifting cylinder (4).

7. The hydraulic control system according to claim 5, characterized in that: A superimposed one-way throttle valve (2.8) is provided between the third reversing valve (2.6) and the auxiliary oil cylinder (5).

8. The hydraulic control system according to claim 5, characterized in that: The first reversing valve (2.4), the second reversing valve (2.5), and the third reversing valve (2.6) are all manually operated valves.

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