(19)
(11)EP 4 053 068 A1

(12)EUROPEAN PATENT APPLICATION
published in accordance with Art. 153(4) EPC

(43)Date of publication:
07.09.2022 Bulletin 2022/36

(21)Application number: 20909257.6

(22)Date of filing:  14.12.2020
(51)International Patent Classification (IPC): 
B66C 23/62(2006.01)
B66C 9/08(2006.01)
B66C 23/53(2006.01)
B66C 23/80(2006.01)
(52)Cooperative Patent Classification (CPC):
B66C 23/62; B66C 23/53; B66C 23/80; B66C 9/08
(86)International application number:
PCT/CN2020/136066
(87)International publication number:
WO 2021/135902 (08.07.2021 Gazette  2021/27)
(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
Designated Extension States:
BA ME
Designated Validation States:
KH MA MD TN

(30)Priority: 30.12.2019 CN 201911394243
30.12.2019 CN 201922439338 U

(71)Applicants:
  • Shandong Marine Energy Co., Ltd.
    Qingdao, Shandong 266000 (CN)
  • Shandong Offshore Equipment Co., Ltd.
    Qingdao, Shandong 266000 (CN)
  • Shandong Offshore Research Institute Co., Ltd.
    Qingdao, Shandong 266000 (CN)

(72)Inventors:
  • LI, Yadong
    Qingdao, Shandong 266000 (CN)
  • LIU, Xiquan
    Qingdao, Shandong 266000 (CN)
  • LI, Yunfeng
    Qingdao, Shandong 266000 (CN)
  • SUN, Yuanhui
    Qingdao, Shandong 266000 (CN)
  • XIN, Peng
    Qingdao, Shandong 266000 (CN)
  • LV, Tao
    Qingdao, Shandong 266000 (CN)
  • LV, Xiaohui
    Qingdao, Shandong 266000 (CN)
  • LIU, Peng
    Qingdao, Shandong 266000 (CN)
  • LI, Jianwen
    Qingdao, Shandong 266000 (CN)
  • SUN, Tao
    Qingdao, Shandong 266000 (CN)
  • SONG, Yongjie
    Qingdao, Shandong 266000 (CN)

(74)Representative: Bayramoglu et al. 
Mira Office Kanuni Sultan Süleyman Boulevard 5387 Street Beytepe, floor 12, no:50
06800 Cankaya, Ankara
06800 Cankaya, Ankara (TR)

  


(54)LIFTING SYSTEM WITH THREE-WAY MOTION COMPENSATION FUNCTION


(57) Disclosed is a lifting system with a three-way motion compensation function, including a main arm (1), a mobile cart I (5), a mobile cart II (2), a support II (3), a support I (4), a lifting mechanism (6), and a vessel body (7), where a front end of the main arm (1) is mounted at an upper end of the mobile cart I (5); a rear end of the main arm (1) is mounted at an upper end of the mobile cart II (2); a lower end of the mobile cart I (5) is mounted on the support I (4); a lower end of the mobile cart II (2) is mounted on the support II (3); the support I (3) and the support II (4) are separately fixed on the vessel body (7); rails I (11) are mounted on two sides of a bottom of the front end of the main arm (1); concave rails II (12) are mounted on two sides of the rear end of the main arm (1); the main arm (1) is driven to move front and back when the mobile cart I (5) and the mobile cart II (2) act synchronously; and the lifting mechanism (6) for driving a lifted object to move up and down is hinged to the front end of the main arm (1). The lifting system can perform a three-way motion compensation function, and can effectively avoid mechanical collision, position deviation, or the like caused by rolling, pitching, or heaving of the vessel body (7), thereby having high lifting efficiency, low comprehensive costs, and wide applicability.




Description

TECHNICAL FIELD



[0001] The present disclosure relates to a lifting system with a three-way motion compensation function, and belongs to the technical field of ocean engineering.

BACKGROUND



[0002] In an offshore operation, a vessel body moves with a wave in a sea condition, and devices on the vessel body also move with the wave, causing phenomena such as imbalance of stress on a lifting device, mechanical collision, and constant change of a lifting position. In addition, a synchronous lifting process is hard to guarantee; or even, a marine accident is caused. Heave compensation in a vertical direction is generally used in the prior art, but heave compensation has an unsatisfactory compensation effect and a complex structure. In a double-vessel hoisting method proposed recently, based on the lever principle, a boom is provided with a ballast buoy at a front end and a counterweight tank at a rear end. In a lifting operation, water is discharged from the buoy, and the counterweight tank is filled with water, thereby jointly increasing a lifting force. However, the double-vessel hoisting method has the following defects: (1) It requires a complex structure, and takes a long time to fill and discharge water. (2) In this operation, a lifted object may collide with the vessel body because of shaking of the vessel body. (3) Lifting efficiency is low.

SUMMARY



[0003] To overcome the above defects in the prior art, the present disclosure provides a lifting system with a three-way motion compensation function to implement three-way motion compensation that avoids an impact of a wave on a lifting device and implements synchronous lifting of a plurality of lifting systems.

[0004] The lifting system with a three-way motion compensation function in the present disclosure includes a main arm, a mobile cart II, a support I, a support II, a mobile cart I, a lifting mechanism, and a vessel body. The front end of the main arm is mounted at an upper end of the mobile cart I. A rear end of the main arm is mounted at an upper end of the mobile cart II. A lower end of the mobile cart I is mounted on the support I. A lower end of the mobile cart II is mounted on the support II. The support I and the support II are separately fixed on the vessel body. Rails I are mounted on two sides of a bottom of the front end of the main arm. Road wheel sets I are mounted at the upper end of the mobile cart I. The rails I are mounted on the road wheel sets I. Concave rails II are mounted on two sides of the rear end of the main arm. Road wheel sets II are mounted at the upper end of the mobile cart II and in the concave rails II that are used for limiting up-down motion of the main arm. The main arm moves left and right through the road wheel sets I and the road wheel sets II. Road wheels III are mounted at the lower end of the mobile cart I. Rails IV are symmetrically mounted on two sides of the support I. The road wheels III are mounted on the rails IV and move along the rails IV, thereby enabling the mobile cart I to move front and back relative to the support I. Road wheels IV are mounted at the lower end of the mobile cart II. U-shaped rails IV are mounted on two sides of the support II. The road wheels IV are mounted on the rails IV having a vertical positioning function and move along the rails III, thereby enabling the mobile cart II to move front and back relative to the support II. The main arm is driven to move front and back when the mobile cart I and the mobile cart II act synchronously. The lifting mechanism for driving a lifted object to move up and down is hinged to the front end of the main arm.

[0005] Preferably, two racks I are symmetrically mounted on two sides of the main arm.

[0006] Preferably, racks III are symmetrically mounted on a left side and a right side of the support I.

[0007] Preferably, a pair of hydraulic motors I symmetrically disposed about the main arm are mounted at the upper end of the mobile cart I. A gear is mounted on each of the hydraulic motors I and meshed with the racks I on the main arm, thereby driving the main arm to move. A pair of locking mechanisms I used for locking the main arm and symmetrically disposed about the main arm are mounted at the upper end of the mobile cart I, such that the main arm can be static relative to the mobile cart I. Two road wheel sets I are symmetrically disposed in each of a front side and a rear side of the upper end of the mobile cart I. Four road wheels III are symmetrically disposed on each of a left side and a right side of the lower end of the mobile cart I. A pair of hydraulic motors II symmetrically disposed about the main arm are mounted at the lower end of the mobile cart I. A gear is mounted on each of the hydraulic motors II and meshed with the racks III on the support I, thereby driving the mobile cart I to move. A pair of locking mechanisms II used for locking the mobile cart I and symmetrically disposed about the support I are mounted at the lower end of the mobile cart I, such that the mobile cart I can be static relative to the support I.

[0008] Preferably, each of the locking mechanisms I and the locking mechanisms II includes a locking apparatus mounted on the mobile cart I, as well as the racks I of the main arm and the racks III of the support I, which are meshed with the locking apparatus. Each of the locking apparatuses includes a locking rack whose section takes the shape of an inverted trapezoid. The locking rack is disposed on one side of the racks I/racks III. Two adjustment hydraulic cylinders are hinged to a bottom of the locking rack. A structure defined by the adjustment hydraulic cylinders has a certain included angle and takes the shape of inverted V. Two locking sliders capable of moving left and right are disposed on the locking rack. Each of the locking sliders slides uni-directionally along a slide rail and is provided with an inclined surface matched with the locking rack. The adjustment hydraulic cylinders push the locking rack into the racks I/racks III. The locking rack and the racks I/racks III are meshed with each other. The two locking sliders approach the locking rack. The inclined surfaces of the two locking sliders are fitted with inclined surfaces of the locking rack.

[0009] Preferably, the support II is formed by welding plates together, and a rack II is mounted in a middle of the support II.

[0010] Preferably, the mobile cart II is formed by welding a plate and rectangular tubes together. A hydraulic motor III is mounted in a middle of the mobile cart II. A gear is mounted on the hydraulic motor III and meshed with the rack II on the support II, thereby driving the mobile cart II to move. Guide wheels I are mounted on a left side and a right side of the lower end of the mobile cart II, and are in contact with side walls of the U-shaped rails III, thereby implementing left-right positioning and guiding for the mobile cart II. Four guide wheels II are mounted on a support frame of the mobile cart II, symmetrically disposed about the main arm, and mounted in the concave rails II, thereby performing a front-back guiding function on left-right motion of the main arm.

[0011] Preferably, the lifting mechanism includes a connecting rod, a driving rod, a lifting bracket, and a hydraulic cylinder. One end of the connecting rod is hinged to the lifting bracket, and the other end thereof is hinged to the main arm. One end of the driving rod is hinged to the lifting bracket, and the other end thereof is hinged to the main arm. A rod end of the hydraulic cylinder is hinged to the driving rod, and a barrel end thereof is hinged to the main arm. The lifting bracket moves up and down under the action of stretching of the hydraulic cylinder.

[0012] The present disclosure has the following beneficial effects:
  1. (1) The lifting system can perform a three-way motion compensation function, and can effectively avoid mechanical collision, position deviation, or the like caused by rolling, pitching, or heaving of the vessel body.
  2. (2) The locking systems are disposed in two motion directions of the main arm, such that the main arm can be effectively and reliably locked when there is no need for compensation.
  3. (3) The drive motors, the road wheels, the guide wheels, the guide wheels, the locking mechanisms, and the like are all disposed symmetrically, thereby ensuring that stress is balanced and no extra torque is generated.
  4. (4) The lifting bracket in the lifting mechanism may be further provided with tooling, such as a clamping mechanism, thereby lifting objects of various structures.
  5. (5) A plurality of the lifting systems can be used jointly, thereby having wide applicability. Because hydraulic pressure is used for lifting, the lifting system has high lifting efficiency and low comprehensive costs.

BRIEF DESCRIPTION OF THE DRAWINGS



[0013] 

FIG. 1 is a three-dimensional diagram of a lifting system;

FIG. 2 is a three-dimensional diagram of a main arm;

FIG. 3 is a three-dimensional diagram of an upper portion of a mobile cart I;

FIG. 4 is a three-dimensional diagram of a bottom of a mobile cart I;

FIG. 5 is a three-dimensional diagram of a support I;

FIG. 6 is a three-dimensional diagram of a mobile cart II;

FIG. 7 is a three-dimensional diagram of a support II;

FIG. 8 is a main view of a lifting mechanism; and

FIG. 9 is a main view of a locking mechanism.



[0014] Reference numerals in the accompanying drawings are as follows:

1-main arm, 11-rail I, 12-rail II, and 13-rack I;

2-mobile cart II, 21-road wheel set II, 22-road wheel IV, 23-hydraulic motor III, 24-guide wheel I, and 25-guide wheel II;

3-support II, 31-rail III, and 32-rack II;

4-support I, 41-rail IV, and 42-rack III;

5-mobile cart I, 51-road wheel set I, 52-road wheel III, 53-hydraulic motor I, 54-locking mechanism I, 55-hydraulic motor II, and 56-locking mechanism II;

6-lifting mechanism, 61-connecting rod, 62-driving rod, 63-lifting bracket, and 64-hydraulic cylinder;

7-vessel body; and

8-locking apparatus, 81-locking rack, 82-adjustment hydraulic cylinder, 83-locking slider, and 84-slide rail.


DETAILED DESCRIPTION OF THE EMBODIMENTS



[0015] The technical solutions in the embodiments of the present disclosure will be described below clearly and completely with reference to the accompanying drawings in the embodiments of the present disclosure. It will become apparent that the described embodiments are merely some, rather than, all of the embodiments of the present disclosure. All other examples obtained by a person of ordinary skill in the art based on the examples of the present disclosure without creative efforts shall fall within the protection scope of the present disclosure.

[0016] As shown in FIG. 1, the present disclosure provides a lifting system with a three-way motion compensation function including a main arm 1, a mobile cart I 5, a mobile cart II 2, a support II 3, a support I 4, a lifting mechanism 6, and a vessel body 7. A front end of the main arm 1 is mounted at an upper end of the mobile cart I 5. A rear end of the main arm 1 is mounted at an upper end of the mobile cart II 2 A lower end of the mobile cart I 5 is mounted on the support I 4. A lower end of the mobile cart II 2 is mounted on the support II 3. The lifting mechanism 6 is mounted at the front end of the main arm 1. The support II 3 and the support I 4 are separately fixed on the vessel body 7.

[0017] As shown in FIG. 2 to FIG. 7, rails I 11 are mounted on two sides of a bottom of the front end of the main arm 1. Road wheel sets I 51 are mounted at the upper end of the mobile cart I 5. The rails I 11 are mounted on the road wheel sets I 51. Concave rails II 12 are mounted on two sides of the rear end of the main arm 1. Road wheel sets II 21 are mounted at the upper end of the mobile cart II 2 and in the concave rails II 12 that are used for limiting up-down motion of the main arm 1. The main arm 1 can move left and right through the road wheel sets I 51 and the road wheel sets II 21. Road wheels III 52 are mounted at the lower end of the mobile cart I 5. Rails IV 41 are symmetrically mounted on two sides of the support I 4. The road wheels III 52 are mounted on the rails IV 41 and can move along the rails IV 41, thereby enabling the mobile cart I 5 to move front and back relative to the support II 3. Road wheels IV 22 are mounted at the lower end of the mobile cart II 2. U-shaped rails III 31 are mounted on two sides of the support II 3. The road wheels IV 22 are mounted in the rails III 31 having a vertical positioning function and can move along the rails III 31, thereby enabling the mobile cart II 2 to move front and back relative to the support II 3. The main arm 1 can be driven to move front and back when the mobile cart I 5, and the mobile cart II 2 act synchronously.

[0018] As shown in FIG. 1 and FIG. 8, the lifting mechanism 6 capable of driving a lifted object to move up and down is hinged to the front end of the main arm 1.

[0019] As shown in FIG. 9, each of locking mechanisms I 54 and locking mechanisms II 56 includes a locking apparatus 8 mounted on the mobile cart I 5, as well as racks I 13 of the main arm and racks III 42 of the support I, which are meshed with the locking apparatus 8. Each of the locking apparatuses 8 includes a locking rack 81 whose section takes the shape of an inverted trapezoid. The locking rack 81 is disposed on one side of the racks I 13/racks III 42. Two adjustment hydraulic cylinders 82 are hinged to a bottom of the locking rack 81; a structure defined by the adjustment hydraulic cylinders 82 has a certain included angle and takes the shape of inverted V. Two locking sliders 83 capable of moving left and right are disposed on the locking rack 81. Each of the locking sliders 83 slides uni-directionally along a slide rail 84 and is provided with an inclined surface matched with the locking rack 81. The adjustment hydraulic cylinders push the locking rack 81 into the racks I 13/racks III 42. The locking rack 81 and the racks I 13/racks III 42 are meshed with each other. The two locking sliders 83 approach the locking rack 81, and the inclined surfaces of the two locking sliders 83 are fitted with inclined surfaces of the locking rack 81.

[0020] When an object is lifted, hydraulic motors II 55 and hydraulic motor III 23 act synchronously to adjust a position of the main arm 1 in a front-back direction. Then, hydraulic motors I 53 act to adjust the position of the main arm 1 in a left-right direction; the hydraulic cylinder 64 in the lifting mechanism 6 acts to enable a lifting bracket 63 to approach the lifted object. Cooperating with an accumulator, the lifting mechanism 6 controls stretching of the hydraulic cylinder 64 by detecting stress on the lifting bracket 63, and keeps stress on the lifting bracket 63 unchanged, thereby preforming a passive compensation function. The hydraulic motors I 53, the hydraulic motors II 55, and the hydraulic motor III 23 are controlled by detecting a position offset of the vessel body relative to the lifted object, thereby compensating position deviation of the main arm 1 in the left-right direction and the front-back direction. Finally, the lifting bracket 63 is static relative to the lifted object, and the stress is constant.

[0021] In addition, a plurality of the lifting systems may be used to work jointly based on weight of the lifted object.

[0022] The lifting system can perform a three-way motion compensation function, and can effectively avoid mechanical collision, position deviation, or the like caused by rolling, pitching, or heaving of the vessel body. The locking mechanisms provided in the present disclosure can effectively and reliably lock the main arm when there is no need for compensation. Moreover, the plurality of the lifting systems can be used jointly. The lifting system has wide applicability, and uses hydraulic pressure for lifting, thereby having high lifting efficiency and low comprehensive costs.

[0023] The lifting system can be widely applied to scenarios of ocean engineering.

[0024] A circuit, an electronic component, and a module used in the lifting system are all belong to the prior art, and can be implemented by a person skilled in the art. Description of details is not required. Content provided by the present disclosure does not include improvement on software and a method.

[0025] It should be noted that in this specification, relational terms such as first and second are used only to differentiate an entity or operation from another entity or operation, and do not require or imply that any actual relationship or sequence exists between these entities or operations. In addition, terms "include", "comprise", or any other variants thereof are intended to cover a non-exclusive inclusion, such that a process, a method, an article, or a device that includes a list of elements not only includes those elements, but also includes other elements that are not explicitly listed, or further includes elements inherent to the process, the method, the article, or the device.

[0026] Although the embodiments of the present disclosure have been illustrated and described, it should be understood that those of ordinary skill in the art may make various changes, modifications, replacements, and variations to the above embodiments without departing from the principle and spirit of the present disclosure, and the scope of the present disclosure is limited by the appended claims and their equivalents.


Claims

1. A lifting system with a three-way motion compensation function, comprising

a main arm (1),

a mobile cart II (2),

a support I (4),

a support II (3),

a mobile cart I (5),

a lifting mechanism (6), and

a vessel body (7),

wherein a front end of the main arm (1) is mounted at an upper end of the mobile cart I (5);

a rear end of the main arm (1) is mounted at an upper end of the mobile cart II (2);

a lower end of the mobile cart I (5) is mounted on the support I (4);

a lower end of the mobile cart II (2) is mounted on the support II (3);

the support I (4) and the support II (3) are separately fixed on the vessel body (7); characterized in that

rails I (11) are mounted on two sides of a bottom of the front end of the main arm (1);

road wheel sets I (51) are mounted at the upper end of the mobile cart I (5);

the rails I (11) are mounted on the road wheel sets I (51);

concave rails II (12) are mounted on two sides of the rear end of the main arm (1);

road wheel sets II (21) are mounted at the upper end of the mobile cart II (2) and the road wheel sets II (21) are mounted in the concave rails II (12) configured for limiting up-down motion of the main arm (1);

the main arm (1) moves left and right through the road wheel sets I (51) and the road wheel sets II (21);

road wheels III (52) are mounted at the lower end of the mobile cart I (5);

rails IV (41) are symmetrically mounted on two sides of the support I (4);

the road wheels III (52) are mounted on the rails IV (41) and move along the rails IV (41), to drive the mobile cart I (5) to move front and back relative to the support I (4);

road wheels IV (22) are mounted at the lower end of the mobile cart II (2);

U-shaped rails IV (41) are mounted on two sides of the support II (3);

the road wheels IV (22) are mounted on the rails IV (41) having a vertical positioning function and configured to move along the rails III (31) to drive the mobile cart II (2) to move front and back relative to the support II (3);

the main arm (1) is driven to move front and back when the mobile cart I (5) and the mobile cart II (2) act synchronously; and

the lifting mechanism (6) for driving a lifted object to move up and down is hinged to the front end of the main arm (1).


 
2. The lifting system with a three-way motion compensation function according to claim 1, characterized in that two racks I (13) are symmetrically mounted on two sides of the main arm (1).
 
3. The lifting system having a three-way motion compensation function according to claim 2, characterized in that racks III (42) are symmetrically mounted on a left side and a right side of the support I (4).
 
4. The lifting system having a three-way motion compensation function according to claim 3, characterized in that a pair of hydraulic motors I (53) symmetrically disposed about the main arm (1) are mounted at the upper end of the mobile cart I (5);

a gear is mounted on each of the hydraulic motors I (53) and meshed with the racks I (13) on the main arm (1) to drive the main arm (1) to move;

a pair of locking mechanisms I (54) symmetrically disposed about the main arm (1) are mounted at the upper end of the mobile cart I (5), and the pair of locking mechanisms I (54) are configured for locking the main arm (1) to make the main arm (1) static relative to the mobile cart 1(5);

two road wheel sets I (51) are symmetrically disposed in each of a front side and a rear side of the upper end of the mobile cart I (5); four road wheels III (52) are symmetrically disposed on each of a left side and a right side of the lower end of the mobile cart I (5);

a pair of hydraulic motors II (55) symmetrically disposed about the main arm (1) are mounted at the lower end of the mobile cart I (5);

a gear is mounted on each of the hydraulic motors II (55) and meshed with the racks III (42) on the support I (4) to drive the mobile cart I (5) to move; and

a pair of locking mechanisms symmetrically disposed about the support I (4) are mounted at the lower end of the mobile cart I (5), and the pair of locking mechanisms are configured for locking the mobile cart I (5) to make the mobile cart I (5) static relative to the support I (4).


 
5. The lifting system with a three-way motion compensation function according to claim 4, characterized in that each of the locking mechanisms I (54) and the locking mechanisms II (56) comprises a locking apparatus (8) mounted on the mobile cart I (5); the racks I (13) of the main arm and the racks III (42) of the support I are meshed with the locking apparatus (8); each of the locking apparatuses (8) comprises a locking rack (81) having a section in a shape of an inverted trapezoid;

the locking rack (81) is disposed on a side of the racks I (13)/racks III (42);

two adjustment hydraulic cylinders (82) are hinged to a bottom of the locking rack (81);

a structure defined by the adjustment hydraulic cylinders (82) has a certain included angle and takes the shape of inverted V;

two locking sliders (83) are movably disposed on a left side and a right side of the locking rack (81);

each of the locking sliders (83) slides uni-directionally along a slide rail (84), and is provided with an inclined surface matched with the locking rack (81);

the adjustment hydraulic cylinders (82) push the locking rack (81) into the racks I (13)/racks III (42);

the locking rack (81) and the racks I (13)/racks III (42) are meshed with each other;

the two locking sliders (83) approach the locking rack (81);

and the inclined surfaces of the two locking sliders (83) are fitted with inclined surfaces of the locking rack (81).


 
6. The lifting system with a three-way motion compensation function according to claim 1, characterized in that the support II (3) is formed by welding plates together; and a rack II (32) is mounted in a middle of the support II (3).
 
7. The lifting system with a three-way motion compensation function according to claim 6, characterized in that the mobile cart II (2) is formed by welding a plate and rectangular tubes together;

a hydraulic motor III (23) is mounted in a middle of the mobile cart II (2);

a gear is mounted on the hydraulic motor III (23) and meshed with the rack II (32) on the support II (3), to drive the mobile cart II (2) to move;

guide wheels I (24) are mounted on a left side and a right side of the lower end of the mobile cart II (2), and are in contact with side walls of the U-shaped rails III (31) to implement left-right positioning and guiding for the mobile cart II (2); and

four guide wheels II (25) are mounted on a support frame of the mobile cart II (2), symmetrically disposed about the main arm (1), and mounted in the concave rails II (12) to perform a front-back guiding function on left-right motion of the main arm (1).


 
8. The lifting system with a three-way motion compensation function according to claim 1, characterized in that the lifting mechanism (6) comprises a connecting rod (61), a driving rod (62), a lifting bracket (63), and a hydraulic cylinder (64);

one end of the connecting rod (61) is hinged to the lifting bracket (63), and the other end of the connecting rod (61) is hinged to the main arm (1);

one end of the driving rod (62) is hinged to the lifting bracket (63), and the other end of the driving rod (62) is hinged to the main arm (1);

a rod end of the hydraulic cylinder (64) is hinged to the driving rod (62), and a barrel end of the hydraulic cylinder (64) is hinged to the main arm (1); and

the lifting bracket (63) moves up and down under the action of stretching of the hydraulic cylinder (64).


 




Drawing
















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