An adjustable counterweight balancing mechanism for a fixed rotating crane

Abstract

This utility model relates to the field of counterweight adjustment technology for tower cranes, specifically, to an adjustable counterweight balancing mechanism for a fixed rotating crane. It includes a counterweight arm horizontally fixedly installed at the upper end of the tower body of the tower crane. In this utility model, when the traction mechanism moves the counterweight block to the target position, aligning both ends of the gantry frame with the selected slots on their corresponding mounting strips, a stepper motor drives the extension shaft and elliptical roller to rotate, moving the contact point between the elliptical roller and the gantry frame to the short axis end of the elliptical roller. During this process, the spring's rebound force pushes the gantry frame vertically downward, causing both ends of the gantry frame to insert into the corresponding slots. Simultaneously, the gantry frame, through the cooperation of its slider and the counterweight block's groove, as well as the action of the sliding rod, jointly restricts the horizontal movement of the counterweight block. Thus, the counterweight block is firmly locked in its current position, preventing the first and second steel cables from bearing tension for extended periods to prevent the counterweight block from moving, thereby extending the service life of the first and second steel cables.

Description

Technical Field

[0001] This utility model relates to the field of counterweight adjustment technology for tower cranes, and more specifically, to an adjustable counterweight balancing mechanism for a fixed rotating crane. Background Technology

[0002] Fixed rotating cranes include tower cranes (or simply tower cranes). A tower crane mainly consists of a tower body, a boom, and a counterweight boom, with counterweights mounted on the counterweight boom. During tower crane operations, when there are significant changes in the load (such as lifting extremely heavy or light materials), increases or decreases in the tower height (adding or lowering sections), or changes in the weight of major components due to maintenance, it is necessary to adjust the counterweights on the counterweight boom to rebalance the overturning moment generated at the boom end and ensure the overall stability of the tower crane. There are two main adjustment methods: one is to increase or decrease the number of counterweights (adding or removing standard counterweights from the counterweight frame); the other is to adjust the position of the movable counterweights (sliding the counterweights along the counterweight boom track using a mechanical device to change their lever arm length).

[0003] In existing technologies, adjusting the position of a movable counterweight is usually done by using a winch to pull it with a steel cable. However, once the counterweight reaches the target position, its initial fixation mainly relies on the tension of the steel cable. To distribute the load and enhance safety, workers need to climb onto a narrow, high-altitude balance arm for additional reinforcement (such as inserting positioning pins, activating locking devices, or adding stop wedges). This operation is difficult and carries the risk of falling from heights or being struck by objects. Even so, if the fixation ultimately still relies mainly on the tension of the steel cable, the steel cable must bear the tension for a long time to prevent the counterweight from moving, which can shorten its lifespan. Once the steel cable breaks due to metal fatigue and the auxiliary fixation fails or is improperly applied, the counterweight can easily move unexpectedly, causing serious safety hazards. Utility Model Content

[0004] The purpose of this invention is to provide an adjustable counterweight balancing mechanism for a fixed rotating crane, in order to solve the problems mentioned in the background art.

[0005] The counterweight is fixed solely by the tension of the steel cable, which means that the steel cable must withstand tension for a long time to prevent the counterweight from moving, which can easily shorten the service life of the steel cable.

[0006] To address the above problems, the present invention aims to provide an adjustable counterweight balancing mechanism for a fixed rotating crane, comprising a counterweight arm horizontally fixedly installed on the upper part of the tower crane's tower body. A counterweight block is disposed above the counterweight arm at a position away from the tower body. A traction mechanism is disposed on the side of the counterweight block closer to the tower body, the traction mechanism being used to drive the counterweight block to move horizontally closer to or away from the tower body. A locking mechanism is disposed on the counterweight block, the locking mechanism comprising a gantry frame straddling the counterweight block and a height adjustment component for driving the gantry frame to move vertically. Mounting strips are fixedly installed at positions corresponding to both ends of the sidewall and the gantry frame. Several slots are horizontally arrayed on the upper sidewall of the mounting strip. When the traction mechanism drives the counterweight to move horizontally, the counterweight drives the gantry frame to move synchronously, so that both ends of the gantry frame pass directly above several slots on the corresponding mounting strip. When the traction mechanism moves the counterweight to the target position, so that both ends of the gantry frame are directly above the selected slots on their corresponding mounting strips, the height adjustment component drives the gantry frame to move vertically downward, so that the lower end of the gantry frame is inserted into the corresponding slot, locking the counterweight in the current position.

[0007] As a further improvement to this technical solution, several steel wheels are horizontally arrayed and rotatably connected to the lower side wall of the counterweight near both sides. The bottom of the steel wheels contacts the upper side wall of the balance arm. Two guide rails are symmetrically fixedly installed on the upper side wall of the balance arm, and the bottoms of the several steel wheels are respectively located inside the two guide rails.

[0008] As a further improvement to this technical solution, a lifting frame is fixedly connected to the upper side wall of the balance arm, and the traction mechanism includes a first take-up roller rotatably disposed on the upper side wall of the lifting frame. A first servo motor is fixedly installed on the upper side wall of the lifting frame through a bracket. The output shaft of the first servo motor is coaxially and fixedly connected to the first take-up roller through a coupling. A first steel cable is wound and fixedly connected on the first take-up roller, and the other end of the first steel cable is fixedly connected to the side of the counterweight block near the tower body.

[0009] As a further improvement to this technical solution, the traction mechanism further includes a second take-up roller rotatably disposed on the upper side wall of the balance arm, a second servo motor is fixedly mounted on the balance arm, the output shaft of the second servo motor is coaxially and fixedly connected to the second take-up roller through a coupling, and a second steel cable is wound and fixedly connected to the second take-up roller.

[0010] As a further improvement to this technical solution, a wheel frame is fixedly installed on the upper side wall of the counterweight block on the side away from the tower body. Two fixed pulleys are rotatably arranged inside the wheel frame. The end of the second steel cable away from the second winding roller passes around the two fixed pulleys and is fixedly connected to the side of the counterweight block away from the tower body.

[0011] As a further improvement to this technical solution, the height adjustment component includes two slide rods that are vertically fixed on the upper side wall of the counterweight. The upper end of the slide rod slides through the upper side wall of the portal frame and is fixedly connected to an end cap. A spring sleeved on the slide rod is provided between the end cap and the upper side wall of the portal frame. The spring pushes the portal frame away from the end cap.

[0012] As a further improvement to this technical solution, a top frame is fixedly installed on the upper side wall of the lifting frame, and the height adjustment component also includes a stepper motor fixedly installed on the upper side wall of the top frame. The output shaft of the stepper motor is coaxially fixedly connected to an extension shaft through a coupling. A support frame is fixedly installed on the upper side wall of the balance arm on the side of the counterweight away from the tower body, and the other end of the extension shaft is rotatably connected to the support frame.

[0013] As a further improvement to this technical solution, the height adjustment component also includes an elliptical roller fixedly connected to the extension shaft, the circumferential surface of which contacts the top side inside the portal frame.

[0014] As a further improvement to this technical solution, the counterweight is provided with grooves on both sides, and a slider is slidably arranged inside the groove, and the slider is integrally fixed to the inner wall of the gantry frame.

[0015] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0016] 1. The adjustable counterweight balancing mechanism of this fixed rotary crane, when the traction mechanism moves the counterweight to the target position, so that the two ends of the gantry frame are respectively aligned with the selected slots on their corresponding mounting strips, the stepper motor drives the extension shaft and the elliptical roller to rotate, moving the contact point between the elliptical roller and the gantry frame to the short axis end of the elliptical roller. During this process, the spring's rebound force pushes the gantry frame to move vertically downward, so that the two ends of the gantry frame are inserted into the corresponding slots. The slots restrict the horizontal movement of the gantry frame. At the same time, the gantry frame, through the cooperation of its slider and the counterweight's groove and the action of the sliding rod, jointly restricts the horizontal movement of the counterweight. Thus, the counterweight is firmly locked in the current position, avoiding the first and second steel cables from bearing tension for a long time to prevent the counterweight from moving, thereby extending the service life of the first and second steel cables. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall device of this utility model after being combined with a tower crane;

[0018] Figure 2 This is a schematic diagram of the overall device of this utility model combined with the rain cover;

[0019] Figure 3 This is a schematic diagram of the overall structure of this utility model;

[0020] Figure 4This is a cross-sectional view of the overall structure of this utility model;

[0021] Figure 5 This is a partial structural schematic diagram of the present invention;

[0022] Figure 6 For the present utility model Figure 5 Exploded view.

[0023] The meanings of the labels in the diagram are as follows:

[0024] 1. Counterweight arm; 11. Guide rail; 12. Lifting frame; 13. Top frame;

[0025] 2. Counterweight; 21. Steel wheel; 22. Slide groove;

[0026] 3. Locking mechanism; 31. Stepper motor; 32. Extension shaft; 33. Elliptical roller; 34. Portal frame; 35. Slide rod; 36. End cap; 37. Spring; 38. Mounting strip; 381. Slot; 39. Support frame;

[0027] 4. Traction mechanism; 41. First take-up roller; 42. First steel cable; 43. Second take-up roller; 44. Second steel cable; 45. Wheel frame; 46. Fixed pulley. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] Example 1

[0030] Please see Figure 1 and Figure 2 As shown, the purpose of this embodiment is to provide an adjustable counterweight balancing mechanism for a fixed rotating crane, including a counterweight arm 1 horizontally fixedly installed at the upper end of the tower body of the tower crane, a counterweight block 2 disposed above the counterweight arm 1 at a position away from the tower body, and a traction mechanism 4 disposed on the side of the counterweight block 2 close to the tower body, the traction mechanism 4 being used to drive the counterweight block 2 to move closer to or away from the tower body in the horizontal direction.

[0031] Since a tower crane is essentially a giant lever system with the tower body as its fulcrum, the counterweight 1 is the lever arm. The torque generated by the counterweight 2 suspended at its end (counterweight force × distance from counterweight 2 to the tower body) is used to balance the overturning moment (load weight × distance from the load to the tower body) generated by the load lifted on the boom (located opposite the counterweight 1). The counterweight 2 is driven to move horizontally along the counterweight 1 by the traction mechanism 4, which can change the distance (i.e., lever arm) from the counterweight 2 to the fulcrum of the tower body. When the counterweight 2 moves away from the tower body, its lever arm increases. With the weight of the counterweight itself remaining unchanged, the balancing torque it generates increases, thus balancing heavier lifting loads or offsetting larger overturning moments. Conversely, when the counterweight 2 moves closer to the tower body, its lever arm decreases, and the balancing torque generated decreases, which is suitable for balancing lighter loads. This dynamic adjustment mechanism ensures that the tower crane can maintain overall stability under various load conditions and effectively prevents overturning.

[0032] Reference Figure 5 Several steel wheels 21 are horizontally arrayed and rotatably connected to the lower side wall of the counterweight 2 near both sides. The bottom of the steel wheels 21 contacts the upper side wall of the balance arm 1. The steel wheels 21 reduce the frictional resistance between the counterweight 2 and the balance arm 1, thereby facilitating the movement of the counterweight 2 by the traction mechanism 4. (Refer to...) Figure 3 Two guide rails 11 are symmetrically fixedly installed on the upper side wall of the counterweight arm 1. The bottom of several steel wheels 21 are located inside the two guide rails 11 respectively. The guide rails 11 constrain the steel wheels 21 to move only in the direction close to or away from the tower body, thereby limiting the counterweight block 2 from shifting during the movement.

[0033] A lifting frame 12 is fixedly connected to the upper side wall of the counterweight arm 1. The structure of the traction mechanism 4 is detailed below, referring to... Figure 3 and Figure 4The traction mechanism 4 includes a first take-up roller 41 rotatably mounted on the upper side wall of the lifting frame 12. A first servo motor is fixedly mounted on the upper side wall of the lifting frame 12 via a bracket. The output shaft of the first servo motor is coaxially and fixedly connected to the first take-up roller 41 via a coupling. A first steel cable 42 is wound and fixedly connected to the first take-up roller 41. The other end of the first steel cable 42 is fixedly connected to the side of the counterweight 2 near the tower body. The traction mechanism 4 also includes a second take-up roller 43 rotatably mounted on the upper side wall of the counterweight arm 1. A second servo motor is fixedly mounted on the counterweight arm 1. The output shaft is coaxially and fixedly connected to the second take-up roller 43 via a coupling. The second take-up roller 43 is wound and fixedly connected to the second steel cable 44. The counterweight 2 is provided with a wheel frame 45 fixedly installed on the upper side wall of the balance arm 1 on the side away from the tower body. The wheel frame 45 is rotatably provided with two fixed pulleys 46. The end of the second steel cable 44 away from the second take-up roller 43 passes around the two fixed pulleys 46 and is fixedly connected to the side of the counterweight 2 away from the tower body. The path of the second steel cable 44 passes between the counterweight 2 and the balance arm 1. The first steel cable 42 and the second steel cable 44 are always kept taut.

[0034] When it is necessary to drive the counterweight 2 closer to the tower body, the first servo motor drives the first winding roller 41 to rotate, and the first winding roller 41 winds up the first steel cable 42, thereby causing the first steel cable 42 to pull the counterweight 2 towards the tower body. At the same time, the second servo motor drives the second winding roller 43 to rotate, and the second winding roller 43 unwinds the second steel cable 44 by an equal amount to avoid the second steel cable 44 from obstructing the movement of the counterweight 2.

[0035] When it is necessary to drive the counterweight 2 away from the tower body, the second servo motor drives the second take-up roller 43 to rotate in the opposite direction. The second take-up roller 43 winds up the second steel cable 44. The second steel cable 44 pulls the counterweight 2 towards the wheel frame 45 (i.e. away from the tower body) through the fixed pulley 46. At the same time, the first servo motor drives the first take-up roller 41 to rotate in the opposite direction. The first take-up roller 41 unwinds the first steel cable 42 by an equal amount to avoid the first steel cable 42 from obstructing the movement of the counterweight 2.

[0036] To improve the stability of the counterweight 2 after it moves to the target position, a locking mechanism 3 is provided on the counterweight 2. The locking mechanism 3 includes a gantry frame 34 spanning the counterweight 2 and a height adjustment component for driving the gantry frame 34 to move vertically. Mounting strips 38 are fixedly installed on the upper side wall of the balance arm 1 at positions corresponding to both ends of the gantry frame 34. Several slots 381 are horizontally arrayed on the upper side wall of the mounting strips 38. When the traction mechanism 4 drives the counterweight 2 to move horizontally, the counterweight 2 drives the gantry frame 34 to move synchronously, so that both ends of the gantry frame 34 move from their corresponding mounting positions. The counterweight 2 passes directly above several slots 381 on the strip 38. When the traction mechanism 4 moves the counterweight 2 to the target position, so that the two ends of the gantry frame 34 are directly above the selected slots 381 on their corresponding mounting strips 38, the height adjustment component drives the gantry frame 34 to move vertically downward, so that the lower end of the gantry frame 34 is inserted into the corresponding slots 381, locking the counterweight 2 in the current position. This locking mechanism avoids the first steel cable 42 and the second steel cable 44 from bearing tension for a long time to prevent the counterweight 2 from moving, thereby extending the service life of the first steel cable 42 and the second steel cable 44.

[0037] It should be noted that both the first and second servo motors are centrally controlled by a control device installed inside the tower crane's cab. With the help of this control device, the synchronous operation of the two servo motors can be precisely coordinated and controlled. The control device precisely controls the rotation angle of the output shafts of the first and second servo motors through a preset program, thereby achieving precise positioning of the counterweight 2 at the target position. When the traction mechanism 4 moves the counterweight 2 to the target position, this precise control ensures that both ends of the gantry frame 34 are precisely positioned directly above the selected slot 381, thus ensuring that the lower end of the vertically descending gantry frame 34 can be accurately inserted into the selected slot 381. After locking is completed, as long as the final total counterweight torque (weight of counterweight 2 × distance between counterweight 2 and the tower body rotation center) is equal to or slightly greater than the overturning torque generated by the load (load weight × load amplitude), the overall balance and stability of the tower crane can be ensured.

[0038] The principle of this control device precisely controlling the rotation angle of the output shafts of the first and second servo motors through a preset program is existing technology, so it will not be elaborated here.

[0039] Reference Figure 6 Slide grooves 22 are provided on both sides of the counterweight 2. A slider is slidably arranged inside the slide groove 22. The slider is integrally fixed with the inner wall of the gantry frame 34. The cooperation between the slider and the slide groove 22 restricts the gantry frame 34 to only move vertically. On the other hand, it also prevents the relative displacement between the gantry frame 34 and the counterweight 2 in the horizontal direction, thereby ensuring that the gantry frame 34 can effectively lock the position of the counterweight 2 by cooperating with the slot 381.

[0040] The structure of locking mechanism 3 is described in detail below, with reference to... Figure 3 The height adjustment assembly includes two vertically fixed sliding rods 35 mounted on the upper sidewall of the counterweight 2. The upper ends of the sliding rods 35 slide through the upper sidewall of the portal frame 34 and are fixedly connected to end caps 36. A spring 37 is sleeved on the sliding rods 35 between the end caps 36 and the upper sidewall of the portal frame 34. The springs 37 push the portal frame 34 away from the end caps 36. A top frame 13 is fixedly installed on the upper sidewall of the lifting frame 12. The height adjustment assembly also includes a stepper motor 31 fixedly installed on the upper sidewall of the top frame 13. The output shaft is coaxially fixedly connected to the extension shaft 32 via a coupling. The counterweight 2 is provided with a support frame 39 fixedly installed on the upper side wall of the counterweight arm 1 on the side away from the tower body. The other end of the extension shaft 32 is rotatably connected to the support frame 39. The height adjustment component also includes an elliptical roller 33 fixedly connected to the extension shaft 32. During the process of the traction mechanism 4 driving the counterweight 2 and the portal frame 34 to move and stop at any position, the circumferential surface of the elliptical roller 33 always keeps in contact with the top side inside the portal frame 34.

[0041] In the initial state, the end of the elliptical roller 33 corresponding to the long axis is in contact with the top side inside the portal frame 34. At this time, the portal frame 34 is at its highest position of travel, and the distance between it and the end cap 36 is the smallest. The spring 37 is in a compressed state, and at the same time, both ends of the portal frame 34 are suspended above the corresponding mounting strip 38 to avoid the mounting strip 38 from obstructing the movement of the portal frame 34 and the counterweight 2. When the traction mechanism 4 moves the counterweight 2 to the target position, so that both ends of the portal frame 34 are directly above the selected slot 381 on its corresponding mounting strip 38, the stepper motor 31 starts, and its output shaft drives the extension shaft 32 to rotate 90 degrees. The extension shaft 32 drives the elliptical roller 33 to rotate synchronously. After rotation, the contact point between the elliptical roller 33 and the gantry frame 34 becomes the end corresponding to the short axis of the elliptical roller 33. During this process, the rebound force of the spring 37 pushes the gantry frame 34 downward away from the end cap 36, causing the gantry frame 34 to move vertically downward. This shortens the distance between the top side inside the gantry frame 34 and the extension shaft 32. Finally, both ends of the gantry frame 34 are inserted into the corresponding two slots 381. The slots 381 restrict the horizontal movement of the gantry frame 34. The gantry frame 34, through the cooperation of its slider and the groove 22 on the counterweight 2 (and the guiding effect of the slide rod 35), restricts the horizontal movement of the counterweight 2, thereby firmly locking the counterweight 2 in the current position.

[0042] It should be noted that the stepper motor 31 is also controlled by the control equipment installed inside the tower crane cab. After the traction mechanism 4 moves the counterweight 2 to the target position and makes the two ends of the gantry frame 34 precisely positioned above the selected slot 381, the operator can control the stepper motor 31 through the control equipment to accurately insert the lower end of the gantry frame 34 into the selected slot 381, thereby locking the position of the counterweight 2.

[0043] Furthermore, the first servo motor, the second servo motor, and the stepper motor 31 are all waterproof motors, as shown in the reference. Figure 2 As can be seen, rain covers are installed on both the lifting frame 12 and the top frame 13. The first servo motor, the second servo motor and the stepper motor 31 are all located inside the rain cover. The rain cover can prevent rainwater from contacting the above-mentioned electrical appliances, further reducing the risk of damage to the electrical appliances due to water ingress.

[0044] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A fixed slewing crane adjustable counterweight balancing mechanism comprising a balance arm (1) horizontally fixedly mounted on the upper end of the tower of a tower crane, characterized in that: A counterweight (2) is provided above the counterweight arm (1) at a position away from the tower body. A traction mechanism (4) is provided on the side of the counterweight (2) near the tower body. The traction mechanism (4) is used to drive the counterweight (2) to move horizontally closer to or away from the tower body. A locking mechanism (3) is provided on the counterweight (2). The locking mechanism (3) includes a gantry frame (34) straddling the counterweight (2) and a height adjustment component for driving the gantry frame (34) to move vertically. Mounting strips (38) are fixedly installed on the upper side wall of the counterweight arm (1) at positions corresponding to both ends of the gantry frame (34). The upper side wall of the mounting strips (38) is horizontally arrayed with... There are several slots (381). When the traction mechanism (4) drives the counterweight (2) to move horizontally, the counterweight (2) drives the gantry frame (34) to move synchronously, so that the two ends of the gantry frame (34) pass directly above the several slots (381) on the corresponding mounting strip (38). When the traction mechanism (4) moves the counterweight (2) to the target position, so that the two ends of the gantry frame (34) are directly above the selected slots (381) on their corresponding mounting strips (38), the height adjustment component drives the gantry frame (34) to move vertically downward, so that the lower end of the gantry frame (34) is inserted into the corresponding slot (381), locking the counterweight (2) in the current position.

2. A fixed rotation crane adjustable counterweight balancing mechanism according to claim 1, characterized in that: The counterweight (2) has several steel wheels (21) arranged in a horizontal array near both sides on its lower side wall. The bottom of the steel wheels (21) contacts the upper side wall of the balance arm (1). The upper side wall of the balance arm (1) is symmetrically fixed with two guide rails (11), and the bottom of the steel wheels (21) is located inside the two guide rails (11).

3. A fixed rotation crane adjustable counterweight balancing mechanism according to claim 1, characterized in that: The upper side wall of the balance arm (1) is fixedly connected to a lifting frame (12). The traction mechanism (4) includes a first take-up roller (41) rotatably mounted on the upper side wall of the lifting frame (12). A first servo motor is fixedly installed on the upper side wall of the lifting frame (12) by a bracket. The output shaft of the first servo motor is coaxially fixedly connected to the first take-up roller (41) through a coupling. A first steel cable (42) is wound and fixedly connected on the first take-up roller (41). The other end of the first steel cable (42) is fixedly connected to the counterweight (2) on the side close to the tower body.

4. A fixed rotation crane adjustable counterweight balancing mechanism according to claim 3, characterised in that: The traction mechanism (4) further includes a second take-up roller (43) rotatably mounted on the upper side wall of the balance arm (1). A second servo motor is fixedly mounted on the balance arm (1). The output shaft of the second servo motor is coaxially fixedly connected to the second take-up roller (43) via a coupling. A second steel cable (44) is wound and fixedly connected on the second take-up roller (43).

5. A fixed rotation crane adjustable counterweight balancing mechanism according to claim 4, characterised in that: The counterweight (2) is provided with a wheel frame (45) fixedly installed on the upper side wall of the balance arm (1) on the side away from the tower body. The wheel frame (45) is provided with two fixed pulleys (46) inside. The end of the second steel cable (44) away from the second winding roller (43) passes around the two fixed pulleys (46) and is fixedly connected to the side of the counterweight (2) away from the tower body.

6. A fixed rotation crane adjustable counterweight balancing mechanism according to claim 1, characterized in that: The height adjustment component includes two vertically fixed sliding rods (35) on the upper side wall of the counterweight (2). The upper end of the sliding rod (35) slides through the upper side wall of the portal frame (34) and is fixedly connected to an end cap (36). A spring (37) sleeved on the sliding rod (35) is provided between the end cap (36) and the upper side wall of the portal frame (34). The spring (37) pushes the portal frame (34) away from the end cap (36).

7. The adjustable counterweight balancing mechanism for a fixed rotating crane according to claim 3, characterized in that: The upper side wall of the lifting frame (12) is fixedly installed with a top frame (13). The height adjustment component also includes a stepper motor (31) fixedly installed on the upper side wall of the top frame (13). The output shaft of the stepper motor (31) is coaxially fixedly connected to an extension shaft (32) via a coupling. The counterweight (2) is provided with a support frame (39) fixedly installed on the upper side wall of the counterweight arm (1) on the side away from the tower body. The other end of the extension shaft (32) is rotatably connected to the support frame (39).

8. The adjustable counterweight balancing mechanism for a fixed rotating crane according to claim 7, characterized in that: The height adjustment assembly also includes an elliptical roller (33) fixedly connected to the extension shaft (32), the circumferential surface of which contacts the top side inside the gantry frame (34).

9. The adjustable counterweight balancing mechanism for a fixed rotating crane according to claim 1, characterized in that: The counterweight (2) has grooves (22) on both sides, and a slider is slidably arranged inside the groove (22). The slider is integrally fixed with the inner wall of the gantry frame (34).

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