A spreader for a port crane

Abstract

A kind of spreader for port crane, it is related to spreader device field, including rectangular frame, rectangular frame is equipped with hook box, connecting rod type transmission assembly is installed in rectangular frame, load-bearing separate type anti-misoperation hook is equipped in hook box, load-bearing separate type anti-misoperation hook includes inverted T hook, rotating load-bearing assembly, locking assembly and indicating component, inverted T hook is located in hook box, inverted T hook is clearance fit with hook box, rotating load-bearing assembly is located in hook box, rotating load-bearing assembly is rotatably connected with hook box, rotating load-bearing assembly is fixedly connected with inverted T hook, connecting rod type transmission assembly is drivingly connected with rotating load-bearing assembly, locking assembly is connected with hook box, locking assembly is connected with inverted T hook, indicating component is fixedly connected with inverted T hook, indicating component is rotatably connected with hook box, beneficial effect: avoid container after being hoisted in unstable three-point load-bearing state, improve the safety of hoisting.

Description

Technical Field

[0001] This utility model relates to the field of lifting device technology, and in particular to a lifting device for port cranes. Background Technology

[0002] As is well known, in port container lifting operations, there are various types of spreaders, including fully automatic, semi-automatic, and manual spreaders, depending on the degree of automation and cost. Among them, semi-automatic spreaders are widely used in multi-purpose gantry cranes and ship cranes due to their good balance of cost, reliability, and operational flexibility.

[0003] Chinese patent CN214031382U describes a container spreader for securing containers on a port crane. It includes a spreader frame, lugs, a turntable, a counterweight, gears, and a toothed plate. The counterweight drives the turntable to rotate, which in turn causes the gears and toothed plate to rotate the locking mechanism 90 degrees, improving ease of operation. However, in practical use, the following problems still exist:

[0004] Traditional semi-automatic spreader systems connect to the crane's main lifting mechanism via rigid ropes to bear the entire weight of the container. Simultaneously, an elastic rope drives a transmission assembly. During operation, the operator remotely positions and lowers the spreader, inserting the hooks into the holes in the container's corner fittings. Then, the elastic ropes are retracted to drive the transmission assembly, causing all hooks to rotate 90 degrees synchronously for locking. Finally, the crane lifts the container via the rigid ropes. However, because the operator is far from the spreader, it is difficult to ensure that all four hooks are accurately inserted into the container's corner holes. Two situations may occur during actual operations: First, a hook may not be inserted into the corner hole but may be held in place by the top of the container or other structures. In this case, if the rotation locking action is completed, the hook may not actually be effectively locked in. Second, a hook may be completely suspended in the air and not in contact with the container. Both of these situations will cause the container to be in an unstable three-point load dangerous state during lifting. During the vertical lifting stage, this off-center load is not obvious and is not easily detected. However, when the horizontal movement begins or when encountering wind or swaying, the off-center load moment will increase sharply, which may easily lead to serious safety accidents such as container slippage and falling.

[0005] Therefore, a lifting device for port cranes is proposed. Utility Model Content

[0006] The purpose of this utility model is to overcome the shortcomings of the prior art, solve the problems mentioned in the background art, and provide a lifting device for port cranes.

[0007] To achieve the aforementioned objective, this utility model adopts the following technical solution:

[0008] A lifting device for a port crane includes a rectangular frame, with hook boxes fixedly installed at each of the four corners of the rectangular frame. A linkage-type transmission assembly for controlling the synchronous rotation of the hooks by 90 degrees is installed within the rectangular frame. The hook boxes contain a load-bearing, separable anti-misoperation hook, which includes an inverted T-shaped hook, a rotating load-bearing assembly, a locking assembly, and an indicating assembly. The inverted T-shaped hook is located within the hook box, with its bottom end passing through and fitting a clearance fit with the hook box. The rotating load-bearing assembly is located within the hook box. The component is fitted onto the inverted T-shaped hook. The bottom end of the rotating load-bearing component is rotatably connected to the inner bottom wall of the hook box, and the top end of the rotating load-bearing component is fixedly connected to the inverted T-shaped hook. The driving end of the linkage transmission component is drively connected to the outer wall of the rotating load-bearing component. The top end of the locking component is connected to the lower surface of the hook box, and the bottom end of the locking component is connected to the bottom end of the inverted T-shaped hook. The bottom end of the indicating component is fixedly connected to the upper end face of the inverted T-shaped hook, and the top end of the indicating component passes through the hook box and is rotatably connected to the upper surface of the hook box.

[0009] The inverted T-shaped hook includes a lifting rod and a lifting block. The lifting rod is located inside the hook box. The bottom end of the lifting rod passes through the hook box and is fixedly connected to the upper surface of the lifting block. The lifting rod and the hook box are clearance-fitted. The rotating load-bearing component is sleeved on the lifting rod and is fixedly connected to the top end of the lifting rod. The bottom end of the indicating component is fixedly connected to the upper end face of the lifting rod. The bottom end of the locking component is connected to the upper surface of the lifting block.

[0010] The rotating load-bearing assembly includes a rotating tube, a limiting tube, a return spring, and a driving component. The rotating tube is sleeved on the boom, and the inner wall of the rotating tube is connected to the outer wall of the boom via the driving component. The bottom end of the rotating tube is rotatably connected to the inner bottom wall of the hook box. The driving end of the linkage transmission assembly is hinged to the outer wall of the rotating tube via a pin. The limiting tube is located above the rotating tube and is fixedly sleeved on the top end of the boom. The return spring is sleeved on the outside of the indicating component, and the bottom end of the return spring is fixedly connected to the upper end face of the limiting tube. The top end of the return spring is fixedly connected to the inner top wall of the hook box.

[0011] The driving component includes a number of connecting keys, which are evenly distributed circumferentially along the axis of the boom. An axial sliding groove is provided on the inner wall of the rotating tube. One end of the connecting key is fixedly connected to the outer wall of the boom, and the other end of the connecting key is located in the axial sliding groove and is slidably connected to the inner wall of the axial sliding groove.

[0012] The locking assembly is provided in at least two parts, and the number of the locking assemblies is even, and the locking assemblies are symmetrically distributed on both sides of the boom.

[0013] The locking assembly includes a locking pin and a stress spring. The lower surface of the hook box is provided with a lock cylinder sliding groove. The top end of the locking pin extends into the lock cylinder sliding groove and is slidably connected to the inner wall of the lock cylinder sliding groove. The stress spring is located in the lock cylinder sliding groove. The bottom end of the stress spring is fixedly connected to the upper end face of the locking pin. The top end of the stress spring is fixedly connected to the inner top wall of the lock cylinder sliding groove. The upper surface of the lifting block is provided with a locking groove, and the position of the locking groove corresponds to the position of the bottom end of the locking pin.

[0014] The indicating assembly includes a push rod, an indicating tube, a slider, and an indicating needle. The bottom end of the push rod is fixedly connected to the upper end face of the boom. The top end of the push rod passes through the hook box and is clearance-fitted with the hook box. The indicating tube is sleeved on the push rod and is clearance-fitted with the push rod. The bottom end of the indicating tube is rotatably connected to the upper surface of the hook box. The indicating needle is fixedly installed on the outer wall of the indicating tube. An inclined sliding groove is provided on the inner wall of the indicating tube. One end of the slider is fixedly connected to the outer wall of the push rod, and the other end of the slider is located in the inclined sliding groove and is slidably connected to the inner wall of the inclined sliding groove.

[0015] Compared with the prior art, this utility model has the following advantages: By using the locking pin and locking groove to achieve mechanical locking when the hook is abnormally lifted, it avoids the container being in an unstable three-point load-bearing state after lifting due to the single hook not being inserted but being forced to complete the rotation locking, thereby preventing possible accidents such as uneven loading, slippage or overturning, and improving the safety of lifting operations; By using a purely mechanical status indicator composed of a push rod, an inclined sliding groove and an indicating rotary tube, it avoids the container being dangerously lifted and moved in an uneven load-bearing state due to the failure to detect the hidden fault of the single hook being completely suspended in time, allowing the operator to visually identify the fault point from a distance and intervene immediately, preventing potential safety risks and further improving the safety of lifting operations. Attached Figure Description

[0016] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0017] Figure 2 This is a top view of the structure of this utility model;

[0018] Figure 3 This is a structural schematic diagram of the present invention viewed from below;

[0019] Figure 4 This is a cross-sectional structural diagram of the hook box of this utility model;

[0020] Figure 5 This is a cross-sectional structural diagram of the connector of this utility model;

[0021] Figure 6 This utility model Figure 1 A magnified structural diagram of point A is shown below;

[0022] Figure 7 This utility model Figure 4 A magnified structural diagram of point B is shown below;

[0023] Figure 8 This utility model Figure 5 A magnified structural diagram of point C is shown below;

[0024] Figure 9 This utility model Figure 5 A magnified structural diagram of point D is shown.

[0025] 1. Rectangular frame; 2. Hook box; 3. Linkage transmission assembly; 4. Inverted T-shaped hook; 5. Lifting rod; 6. Lifting block; 7. Rotating tube; 8. Limiting tube; 9. Return spring; 10. Connecting key; 11. Axial sliding groove; 12. Locking pin; 13. Stress spring; 14. Lock core sliding groove; 15. Lock groove; 16. Push rod; 17. Indicating rotating tube; 18. Slider; 19. Indicating needle; 20. Inclined sliding groove. Detailed Implementation

[0026] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood through the specific circumstances.

[0027] Additional aspects and advantages of this invention will be further set forth in the description which follows in conjunction with the accompanying drawings, and in part will be obvious from the description or may be learned by practice of the invention.

[0028] like Figure 1-5As shown, a lifting device for a port crane includes a rectangular frame 1. Hook boxes 2 are fixedly installed at each of the four corners of the rectangular frame 1. A linkage-type transmission assembly 3, controlling the synchronous rotation of the hooks by 90 degrees, is installed inside the rectangular frame 1. The hook box 2 contains a load-bearing-separated anti-misoperation hook, which includes an inverted T-shaped hook 4, a rotating load-bearing assembly, a locking assembly, and an indicating assembly. The inverted T-shaped hook 4 is located inside the hook box 2, with its bottom end passing through the hook box 2 and fitting with it in a clearance fit. The rotating load-bearing assembly is located within the hook box. Inside 2, the rotating load-bearing component is sleeved on the inverted T-shaped hook 4. The bottom end of the rotating load-bearing component is rotatably connected to the inner bottom wall of the hook box 2, and the top end of the rotating load-bearing component is fixedly connected to the inverted T-shaped hook 4. The driving end of the linkage transmission component 3 is connected to the outer wall of the rotating load-bearing component. The top end of the locking component is connected to the lower surface of the hook box 2, and the bottom end of the locking component is connected to the bottom end of the inverted T-shaped hook 4. The bottom end of the indicating component is fixedly connected to the upper surface of the inverted T-shaped hook 4, and the top end of the indicating component passes through the hook box 2 and is rotatably connected to the upper surface of the hook box 2.

[0029] like Figure 7 and Figure 8 As shown, the inverted T-shaped hook 4 includes a lifting rod 5 and a lifting block 6. The lifting rod 5 is located inside the hook box 2. The bottom end of the lifting rod 5 passes through the hook box 2 and is fixedly connected to the upper surface of the lifting block 6. The lifting rod 5 and the hook box 2 are fitted with a clearance. The rotating load-bearing component is sleeved on the lifting rod 5 and is fixedly connected to the top end of the lifting rod 5. The bottom end of the indicating component is fixedly connected to the upper end face of the lifting rod 5. The bottom end of the locking component is connected to the upper surface of the lifting block 6.

[0030] like Figure 4 , Figure 5 , Figure 7 , Figure 8 and Figure 9 As shown, the rotating load-bearing assembly includes a rotating tube 7, a limiting tube 8, a return spring 9, and a driving component. The rotating tube 7 is sleeved on the boom 5. The inner wall of the rotating tube 7 is connected to the outer wall of the boom 5 via the driving component. The bottom end of the rotating tube 7 is rotatably connected to the inner bottom wall of the hook box 2. The driving end of the linkage transmission assembly 3 is hinged to the outer wall of the rotating tube 7 via a pin. The limiting tube 8 is located above the rotating tube 7 and is fixedly sleeved on the top end of the boom 5. The return spring 9 is sleeved on the outside of the indicating assembly. The bottom end of the return spring 9 is fixedly connected to the upper end face of the limiting tube 8, and the top end of the return spring 9 is fixedly connected to the inner top wall of the hook box 2.

[0031] like Figure 5 and Figure 8As shown, the driving component includes a connecting key 10. Several connecting keys 10 are provided and are evenly distributed circumferentially along the axis of the rod 5. An axial sliding groove 11 is provided on the inner wall of the rotating tube 7. One end of the connecting key 10 is fixedly connected to the outer wall of the rod 5, and the other end of the connecting key 10 is located in the axial sliding groove 11 and is slidably connected to the inner wall of the axial sliding groove 11.

[0032] like Figure 4 , Figure 5 , Figure 7 and Figure 8 As shown, there are at least two locking components, and the number of locking components is even. The locking components are symmetrically distributed on both sides of the boom 5.

[0033] like Figure 4 , Figure 5 , Figure 7 and Figure 8 As shown, the locking assembly includes a locking pin 12 and a stress spring 13. The lower surface of the hook box 2 is provided with a lock cylinder sliding groove 14. The top end of the locking pin 12 extends into the lock cylinder sliding groove 14 and is slidably connected to the inner wall of the lock cylinder sliding groove 14. The stress spring 13 is located in the lock cylinder sliding groove 14. The bottom end of the stress spring 13 is fixedly connected to the upper end face of the locking pin 12, and the top end of the stress spring 13 is fixedly connected to the inner top wall of the lock cylinder sliding groove 14. The upper surface of the lifting block 6 is provided with a locking groove 15, and the position of the locking groove 15 corresponds to the position of the bottom end of the locking pin 12.

[0034] like Figure 4 , Figure 5 , Figure 6 and Figure 9 As shown, the indicating assembly includes a push rod 16, an indicating tube 17, a slider 18, and an indicating needle 19. The bottom end of the push rod 16 is fixedly connected to the upper end face of the lifting rod 5. The top end of the push rod 16 passes through the hook box 2 and is clearance-fitted with the hook box 2. The indicating tube 17 is sleeved on the push rod 16 and is clearance-fitted with the push rod 16. The bottom end of the indicating tube 17 is rotatably connected to the upper surface of the hook box 2. The indicating needle 19 is fixedly installed on the outer wall of the indicating tube 17. An inclined sliding groove 20 is provided on the inner wall of the indicating tube 17. One end of the slider 18 is fixedly connected to the outer wall of the push rod 16, and the other end of the slider 18 is located in the inclined sliding groove 20 and is slidably connected to the inner wall of the inclined sliding groove 20.

[0035] The work process is as follows:

[0036] S1, In use, the rectangular frame 1 is connected to the lifting end of the crane via a rigid pull rope, and the linkage transmission assembly 3 is connected to the lifting end of the crane via an elastic pull rope. The crane operator manipulates the spreader to align the four hook boxes 2 with the four corner holes on the top of the container. After the spreader is lowered, the lifting blocks 6 of each inverted T-shaped hook 4 are inserted into the corresponding corner holes. The operator controls the crane to pull up the elastic pull rope, which drives the main shaft of the linkage transmission assembly 3 to rotate. The connecting rod of the linkage transmission assembly 3 synchronously pushes the four rotating tubes 7, causing the rotating tubes 7 to rotate 90 degrees synchronously within the hook box 2. The rotating tubes 7 drive the crane through a spline pair composed of a connecting key 10 and an axial sliding groove 11. As boom 5 rotates, the lifting block 6, which is fixedly connected to boom 5, rotates 90 degrees synchronously, causing the lifting block 6 to enter the locking position inside the corner hole of the container. Subsequently, the crane lifts the rectangular frame 1 through the rigid rope to begin lifting. The weight of the container is transferred to boom 5 through the lifting block 6. Boom 5 overcomes the elastic force of the return spring 9 and slides downward relative to the stationary rotating tube 7. The downward movement of boom 5 causes the limiting tube 8 fixed on boom 5 to move downward, eventually making the limiting tube 8 in close contact with the upper end face of the rotating tube 7. Thus, the entire weight of the container is transferred to the rigid rope through the rigid path of boom 5, limiting tube 8, rotating tube 7, hook box 2, and rectangular frame 1, completing the safe lifting.

[0037] S2, During the lifting process, if one of the inverted T-shaped hooks 4 is misaligned and the lifting block 6 fails to insert into the corner hole, but is instead lifted upwards by the top surface of the container, the lifting block 6 will cause the lifting rod 5 to move upwards within the hook box 2. The upward movement of the lifting rod 5 and the lifting block 6 will cause the locking groove 15 on the upper surface of the lifting block 6 to approach the bottom end of the locking pin 12. Continued upward movement will cause the bottom end of the locking pin 12 to fully enter the locking groove 15. At this point, the locking pin 12 is connected to the hook box 2 through the lock core sliding groove 14 and the stress spring 13, preventing relative rotation between the lifting block 6 and the hook box 2. When the operator pulls the elastic rope according to the normal procedure and attempts to drive the linkage transmission assembly 3... The rotating pipe 7 and the boom 5 at the fault point are locked and cannot rotate. The movement of the linkage transmission assembly 3 is blocked, and the entire rotation cannot be completed. Since the rotation is not completed, the crane can only lift the rectangular frame 1 by the rigid rope, thus avoiding lifting the container in a dangerous three-point load-bearing state. The mechanical locking is achieved by the cooperation of the locking pin 12 and the locking groove 15 when the hook is abnormally lifted. This avoids the container being in an unstable three-point load-bearing state after lifting because the single hook is not inserted but is pushed up and forced to complete the rotation lock. This prevents the possible accidents of uneven loading, slippage or overturning, and improves the safety of the lifting operation.

[0038] S3, during hoisting, if one of the inverted T-shaped hooks 4 is in a free-hanging state due to misalignment, when the elastic rope is pulled, the linkage transmission assembly 3 can still drive all the rotating tubes 7 and the boom 5 to rotate 90 degrees. This is because the inverted T-shaped hook 4 is not lifted, the locking pin 12 is not triggered, and the rotation process is unimpeded. After the crane starts hoisting the rectangular frame 1 by lifting it with the rigid rope, the booms 5 of the three locked inverted T-shaped hooks 4 will slide downwards due to the load. The boom 5 drives the push rod 16 to move downwards, and the slider 18 fixed to the outer wall of the push rod 16 slides in the inclined sliding groove 20 on the inner wall of the indicating rotating tube 17. Since the bottom end of the indicating rotating tube 17 is rotatably connected to the upper surface of the hook box 2, the linear motion of the slider 18 is converted into the rotation of the indicating rotating tube 17 through the inclined sliding groove 20. The indicator needle 19 fixed to the outer wall of the indicating rotating tube 17 rotates accordingly. At the same time, the inverted T-shaped hook 4 in the suspended state... Because the T-shaped hook 4 does not bear weight, the boom 5 remains in the upper position under the action of the return spring 9, and the push rod 16 does not move downward. Therefore, the slider 18 corresponding to the hook does not move within the inclined sliding groove 20, and the indicator tube 17 and indicator needle 19 remain stationary. The operator above can clearly see from a distance that one of the four indicator needles 19 is in an abnormal state, and immediately determine that the inverted T-shaped hook 4 at that corner is not working properly. The operator then stops lifting and readjusts the alignment of the spreader. Through the purely mechanical status indicator composed of the push rod 16, the inclined sliding groove 20, and the indicator tube 17, the hidden fault of a single hook being completely suspended and not being detected in time is avoided, which could lead to the container being dangerously lifted and moved under a three-point load-bearing unbalanced state. This allows the operator to visually identify the fault point from a distance and intervene immediately, preventing potential safety risks and further improving the safety of the lifting operation.

[0039] The parts of this utility model not described in detail are prior art. Although this utility model has been specifically shown and introduced in conjunction with preferred embodiments, there are many methods and approaches to implement this technical solution. The above description is only a preferred embodiment of this utility model. However, those skilled in the art should understand that various changes in form and detail can be made to this utility model without departing from the spirit and scope of this utility model as defined by the appended claims, and all such changes shall be within the protection scope of this utility model.

Claims

1. A lifting device for a port crane, comprising a rectangular frame (1), wherein hook boxes (2) are fixedly installed at each of the four corners of the rectangular frame (1), and a linkage-type transmission assembly (3) for controlling the synchronous rotation of the hooks by 90 degrees is installed inside the rectangular frame (1), characterized in that: The hook box (2) is equipped with a load-bearing, separable anti-misoperation hook. The load-bearing, separable anti-misoperation hook includes an inverted T-shaped hook (4), a rotating load-bearing component, a locking component, and an indicating component. The inverted T-shaped hook (4) is located inside the hook box (2), and its bottom end passes through the hook box (2) and is clearance-fitted with it. The rotating load-bearing component is located inside the hook box (2) and is sleeved on the inverted T-shaped hook (4). The bottom end of the rotating load-bearing component is flush with the hook box (2). The inner bottom wall is rotatably connected, the top end of the rotating load-bearing component is fixedly connected to the inverted T-shaped hook (4), the driving end of the linkage transmission component (3) is rotatably connected to the outer wall of the rotating load-bearing component, the top end of the locking component is connected to the lower surface of the hook box (2), the bottom end of the locking component is connected to the bottom end of the inverted T-shaped hook (4), the bottom end of the indicating component is fixedly connected to the upper end face of the inverted T-shaped hook (4), and the top end of the indicating component passes through the hook box (2) and is rotatably connected to the upper surface of the hook box (2).

2. A lifting device for a port crane according to claim 1, characterized in that: The inverted T-shaped hook (4) includes a lifting rod (5) and a lifting block (6). The lifting rod (5) is located inside the hook box (2). The bottom end of the lifting rod (5) passes through the hook box (2) and is fixedly connected to the upper surface of the lifting block (6). The lifting rod (5) and the hook box (2) are in clearance fit. The rotating load-bearing component is sleeved on the lifting rod (5) and is fixedly connected to the top end of the lifting rod (5). The bottom end of the indicating component is fixedly connected to the upper end face of the lifting rod (5). The bottom end of the locking component is connected to the upper surface of the lifting block (6).

3. A lifting device for a port crane according to claim 2, characterized in that: The rotating load-bearing assembly includes a rotating tube (7), a limiting tube (8), a return spring (9), and a driving component. The rotating tube (7) is sleeved on the boom (5). The inner wall of the rotating tube (7) is connected to the outer wall of the boom (5) through the driving component. The bottom end of the rotating tube (7) is rotatably connected to the inner bottom wall of the hook box (2). The driving end of the linkage transmission assembly (3) is hinged to the outer wall of the rotating tube (7) through a pin. The limiting tube (8) is located above the rotating tube (7). The limiting tube (8) is fixedly sleeved on the top end of the boom (5). The return spring (9) is sleeved on the outside of the indicator assembly. The bottom end of the return spring (9) is fixedly connected to the upper end face of the limiting tube (8). The top end of the return spring (9) is fixedly connected to the inner top wall of the hook box (2).

4. A lifting device for a port crane according to claim 3, characterized in that: The driving component includes a connecting key (10), and there are several connecting keys (10), which are evenly distributed circumferentially along the axis of the rod (5). An axial sliding groove (11) is provided on the inner wall of the rotating tube (7). One end of the connecting key (10) is fixedly connected to the outer wall of the rod (5), and the other end of the connecting key (10) is located in the axial sliding groove (11) and is slidably connected to the inner wall of the axial sliding groove (11).

5. A lifting device for a port crane according to claim 4, characterized in that: The locking components are provided in at least two, and the number of locking components is even, and the locking components are symmetrically distributed on both sides of the boom (5).

6. A lifting device for a port crane according to claim 5, characterized in that: The locking assembly includes a locking pin (12) and a stress spring (13). The lower surface of the hook box (2) is provided with a lock cylinder sliding groove (14). The top end of the locking pin (12) extends into the lock cylinder sliding groove (14) and is slidably connected to the inner wall of the lock cylinder sliding groove (14). The stress spring (13) is located in the lock cylinder sliding groove (14). The bottom end of the stress spring (13) is fixedly connected to the upper end face of the locking pin (12). The top end of the stress spring (13) is fixedly connected to the inner top wall of the lock cylinder sliding groove (14). The upper surface of the lifting block (6) is provided with a locking groove (15), and the position of the locking groove (15) corresponds to the position of the bottom end of the locking pin (12).

7. A lifting device for a port crane according to claim 6, characterized in that: The indicating assembly includes a push rod (16), an indicating tube (17), a slider (18), and an indicating needle (19). The bottom end of the push rod (16) is fixedly connected to the upper end face of the boom (5). The top end of the push rod (16) passes through the hook box (2) and is clearance-fitted with the hook box (2). The indicating tube (17) is sleeved on the push rod (16) and is clearance-fitted with the push rod (16). The bottom end of the indicating tube (17) is rotatably connected to the upper surface of the hook box (2). The indicating needle (19) is fixedly installed on the outer wall of the indicating tube (17). An inclined sliding groove (20) is provided on the inner wall of the indicating tube (17). One end of the slider (18) is fixedly connected to the outer wall of the push rod (16). The other end of the slider (18) is located in the inclined sliding groove (20) and is slidably connected to the inner wall of the inclined sliding groove (20).

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