Self-unloading device and method for cargo boom of flat-head tower crane

Abstract

The invention relates to the field of tower cranes, and discloses a flat head type tower crane boom dumping device which comprises a lifting device installed on a balance arm, a luffing device and a crane carriage, the luffing device and the crane carriage are installed on a crane boom, a hoisting platform is installed on the crane carriage and stretches across the crane boom, and a suspension arm is installed at the top of the hoisting platform; the cargo boom at the front end of the main machine is dismantled section by section through the self-discharging device so as to achieve the boom reducing effect, and therefore the roof crane only needs to stand for dismantling the main machine at a time. According to the method, one-time roof crane station is reduced, that is, one-time roof crane dismounting and mounting are reduced, reinforcement of a building structure at the roof crane station is reduced, the economic cost and the time cost are saved, and the safety risk of mounting and dismounting the roof crane is also reduced.

Description

Technical Field

[0001] The present invention relates to the field of tower cranes, and particularly to a self-unloading device and method for the boom of a flat-top tower crane. Background Art

[0002] For the demolition of internal climbing and external hanging tower cranes (hereinafter referred to as the main machine), a roof crane is usually used as an auxiliary demolition tool. However, for large floor areas, as Figure 1 shown, the boom of the main machine a is relatively long, while the boom length of the roof crane b is not sufficient to demolish the main machine a at one time. Therefore, in the prior art, the roof crane b needs to be repositioned twice. The roof crane b positions for the first time to demolish the front boom of the main machine a. After completion, it is demolished and reinstalled. The roof crane b positions for the second time to demolish the remaining components of the main machine a. Such a technology requires the repeated disassembly and assembly of the roof crane b at the top of the building. Each time the roof crane b is installed, the building structure needs to be reinforced at the positioning point. This results in high economic costs and time costs, and there are also certain safety risks in the installation and demolition of the roof crane b.

[0003] The prior art CN202323457612.7 discloses a self-unloading device for the boom of a tower crane, including a lifting derrick. A rotating part is installed at the bottom end of the lifting derrick, and a moving base is installed at the bottom end of the rotating part. The moving base is installed on both sides of the boom section. An adjusting handle is installed inside the moving base. A clamping member a is installed inside the moving base, and the clamping member a is connected to the adjusting handle. A clamping member b is installed inside the moving base, and the clamping member b is connected to the adjusting handle. Pulleys are installed at both the upper and lower ends inside the moving base. This technology can move the self-unloading device by using the pulleys installed inside the moving base, so as to adjust the position of the lifting derrick on the boom section, and control the movement of the clamping member a and the clamping member b by rotating the adjusting handle. Although the boom of the tower crane can be disassembled, only by manually operating two independent moving bases to move on the lower chord of the boom section, the position adjustment operation of the moving base is troublesome. And the adopted lifting derrick is directly supported on the lower chord of the boom section, and then a tie rod is used to connect the top end of the lifting derrick and the lower chord of the boom section to make the lifting derrick tilt at a fixed angle. In this way, the angle and lifting range of the lifting derrick are limited, and to meet the lifting requirements of the boom section, the lifting derrick needs to have a large length, and a large length will make it difficult for the flexural strength of the lifting derrick to stably support the lifting of the boom section, and there are relatively large safety risks.

[0004] The present invention gradually disassembles the boom at the front end of the main machine through a self-unloading device to achieve the effect of reducing the boom. Thus, the roof crane only needs to be positioned once for demolishing the main machine. The present invention reduces one positioning of the roof crane, that is, reduces one disassembly and assembly of the roof crane, reduces the reinforcement of the building structure at the positioning point of the roof crane, saves economic costs and time costs, and also reduces the safety risks in the installation and demolition of the roof crane. Summary of the Invention

[0005] The present invention aims to provide a flat-top tower crane boom self-dumping device and method to reduce the cost and safety risks during the self-dumping process of the tower crane boom.

[0006] To achieve the above object, the present invention adopts the following technical solutions: A flat-top tower crane boom self-dumping device includes a hoisting device installed on the counter jib, a luffing device and a trolley hoist installed on the boom. A lifting platform is installed on the trolley hoist, and the lifting platform spans above the boom. A boom is installed on the top of the lifting platform. The hoisting device includes the tower crane's own hoisting mechanism, as well as rope supporting pulleys at the top of the boom and the root of the boom. A pulley is provided at the top of the boom, and a wire rope clamping device is provided on the boom. The hoisting wire rope passes through the rope supporting pulleys and the pulley in sequence from the hoisting mechanism and is connected with a hook. The luffing device includes the tower crane's own luffing mechanism, as well as a rope supporting pulley and a pulley guiding device provided on the previous boom section to be demolished. The luffing wire rope winds from the luffing mechanism through the original rope supporting pulley on the first boom section, the added rope supporting pulley, and the pulley guiding device and is connected to the trolley hoist. The lifting platform includes two trapezoidal platform frames, which are trapezoidally arranged above the boom. A plurality of connecting lugs are provided at the top ends of the two platform frames, and ear seats are provided at the bottom ends of the two platform frames. Bolts are connected between the connecting lugs of the two platform frames, and the boom is also connected to the connecting lugs. The ear seats and the trolley hoist are connected by a pin shaft. The boom is an 8m-long lattice regular triangular cross-section member. Ear seats are provided at the front and rear ends of the bottom of the boom. The front ear seat is rotatably connected to the connecting lug of the lifting platform, and the rear ear seat is connected to the connecting lug of the lifting platform through an adjusting bolt. The adjusting bolt is used to adjust the boom elevation angle between 37° and 55°.

[0007] Preferably, as an improvement, an anti-lifting device is installed on the trolley hoist. The anti-lifting device includes a limit wheel set located at the front and rear ends of the trolley hoist. The limit wheel set includes rollers and two structural plates. The two structural plates are attached to the cross bar of the trolley hoist from the inside and outside, and are fixedly connected by fasteners. The rollers are rotatably connected to the outside of the structural plates, and the rollers are in contact with the bottom of the lower chord of the boom.

[0008] Preferably, as an improvement, the pulley guiding device includes a support rod located below the boom. The two ends of the support rod are connected to the lower chord of the boom, and a guiding pulley is fixedly connected to the middle of the support rod.

[0009] Preferably, as an improvement, the wire rope clamping device is used to fix the hoisting wire rope when the luffing trolley of the crane changes its amplitude. The wire rope clamping device includes a base connected to the main chord of the boom by fasteners. A plurality of clamping seats are arranged side by side on the base. The clamping seat includes an upper groove seat and a lower groove seat that are fastened and connected by fasteners.

[0010] The self-unloading method of the boom of a flat-top tower crane is realized by using a self-unloading device for the boom of a flat-top tower crane, and includes: Step 1: Luff the luffing trolley of the crane to the previous boom section of the section to be demolished through the luffing device, so that the boom hook is located at the center of gravity position of the section to be demolished; Step 2: Tie the section to be demolished with a hoisting wire rope, start the hoisting mechanism to make it bear the force, remove the connecting pin or bolt between the section to be demolished and the previous boom section, and start the hoisting mechanism to lift the section to be demolished; Step 3: Fix the hoisting wire rope with the wire rope clamping device on the boom, and move the luffing trolley towards the root of the boom through the luffing device, and the hoisting wire rope is recovered synchronously; Step 4: Move the trolley to the interior of the building, recover the hoisting wire rope until it is in a taut state, loosen the wire rope clamping device, make the hoisting wire rope in an available state, and start the hoisting mechanism to place the section to be demolished on the roof; Step 5: At this time, the demolition of one boom section is completed, and the section to be demolished becomes the remaining boom section that is the farthest from the root of the boom; Step 6: Repeat the above steps 1 to 5.

[0011] Preferably, as an improvement, between steps 2 and 4, the roller of the anti-lifting device abuts against the lower chord of the boom to prevent the luffing trolley from lifting and tilting.

[0012] The self-unloading technical solution of the present invention breaks through the dependence on the secondary positioning of traditional roof cranes. The core principle is to utilize the hoisting / luffing mechanism of the tower crane main body and combine it with a modular self-unloading device to achieve a closed-loop process of "section-by-section self-disassembly - inward movement - lowering" of the boom. The hoisting wire rope forms a transmission chain of "main engine hoisting mechanism → boom → jib pulley → hook" through the rope-supporting pulleys at the top of the boom and the root of the jib, reusing the original power source of the tower crane and avoiding additional power equipment. The pulley at the top of the jib cooperates with the wire rope clamping device to fix the wire rope during the luffing process, ensuring that the hook always aligns with the center of gravity of the section to be disassembled, and solving the problem of hoisting point deviation caused by the fixed angle of the traditional gin pole. The luffing wire rope winds around the original rope-supporting pulleys + additional rope-supporting pulleys + guiding pulleys on the boom, and synchronously luffs and pulls the hoisting trolley during the disassembly process, making the movement and positioning of the hoisting trolley more automated and accurate. The rope-supporting pulleys move backward section by section with the progress of the demolition, dynamically adapting to the remaining length of the boom, and realizing "one wire for multiple uses" without disassembling the main engine luffing system. The hoisting platform adopts a stable support method of rigid-flexible coupling. The trapezoidal platform frame is connected to the hoisting trolley through a pin shaft, forming a trapezoidal structure straddling above the boom, evenly transferring the jib load to the lower chord of the boom and avoiding single-point stress. The jib elevation angle (37° - 55°) is dynamically adjusted by adjusting bolts. Combined with the 8m lattice equilateral triangle cross-section design, on the premise of ensuring the flexural strength (the stiffness is increased by 40% compared with the traditional gin pole), the hoisting range is maximized (covering the entire section of the boom). The rollers of the limit wheel group contact the bottom surface of the lower chord of the boom, forming a reverse support force during hoisting, offsetting the forward-tilting moment of the trolley, compensating in real time to ensure mechanical balance and avoiding the risk of tipping. Adopting relay lowering in a limited space, after the section to be demolished is moved to the interior of the building, it is lowered by the roof crane in relay (supplementary step four). The self-unloading device is only responsible for "inward movement" rather than the whole process of hoisting, unloading the weight of the wire rope (about reducing the load by 1.2t), making the device lightweight (total weight ≤ 3.2t), and adapting to the narrow space of the internal climbing tower crane.

[0013] The prior art requires secondary positioning. The reinforcement cost for each positioning is approximately 80,000 - 150,000 yuan (calculated based on a 200 m² roof), which takes 48 - 72 hours and there is a risk of high-altitude disassembly and installation. The technical solution of the present invention subverts and reduces the roof crane positioning. By self-unloading section by section (the disassembly time for a single section ≤ 2 hours), the roof crane only needs one positioning, directly saving 50% of the single-time reinforcement cost + construction period, and eliminating the risk of falling / collision during secondary disassembly. Compared with prior arts such as CN202323457612.7, the lattice-type equilateral triangle cross-section + angle-adjustable boom adopted by the present invention has higher flexural strength, and the sectional moment of inertia is increased by more than 60% compared with the prior art, which can support a larger load. The angle adjustment can be accurately controlled by adjusting bolts, and the hoisting horizontal range can reach 4.4 m - 6.2 m, and the hoisting height can reach 4.9 m - 6.5 m, which can meet the greater space requirements for hoisting the boom sections. And it has a lightweight effect, being lighter than the gin pole with the same bearing capacity, reducing the load of the trolley. The luffing device is guided by a rope-supporting pulley, and the moving speed of the trolley can be increased to 0.8 m / s (the traditional manual movement is only 0.15 m / s), and there is no need to stop the machine to adjust the clamping parts (the traditional method requires stopping the machine to tighten every 5 m). The hoisting trolley effectively reduces the risk of the hoisting trolley tipping over during the hoisting process through an anti-lifting device, and the tension fluctuation range of the hoisting wire rope is reduced by more than 65%, which can effectively guarantee the hoisting safety during the disassembly of the boom sections. In the technical solution of the present invention, a large number of components reuse the original hoisting / luffing system of the tower crane, and the equipment transformation cost is lower. Description of the Drawings

[0014] Figure 1 Schematic diagram of the prior art tower crane main engine and roof crane positioning.

[0015] Figure 2 Schematic diagram of the structure of hoisting and luffing in Embodiment 1 of the present invention (in the figure, ① - ⑩ divide the boom to be disassembled into 10 boom sections in this embodiment. During disassembly, they are removed in the order of ⑩ - ⑨ - ⑧ - ⑦ - ⑥ - ⑤ - ④ - ③ - ② - ①).

[0016] Figure 3 Schematic diagram of the structure of the hoisting platform in Embodiment 1 of the present invention.

[0017] Figure 4 Schematic diagram of the structure of the boom in Embodiment 1 of the present invention.

[0018] Figure 5 Schematic diagram of the structure of the wire rope clamping device in Embodiment 1 of the present invention.

[0019] Figure 6 Schematic diagram of the structure of the anti-lifting device in Embodiment 1 of the present invention.

[0020] Figure 7 Schematic diagram of the structure of the pulley guiding device in Embodiment 1 of the present invention.

[0021] The figure marks in the drawings of the specification include: main machine a, roof crane b, lifting mechanism 1, luffing mechanism 2, crane arm 3, lifting platform 4, crane arm 5, lifting trolley 6, rope supporting wheel 7, guide pulley 8, adjusting bolt 9, wire rope clamping device 10, lifting wire rope 11, platform frame 12, connecting lifting ear 13, leveling bolt 14, horizontal ear plate 15, pulley 16, base 17, upper groove seat 18, lower groove seat 19, crane arm lower chord 20, cross bar 21, roller 22, structural plate 23, support rod 24, vertical ear plate 25. DETAILED DESCRIPTION

[0022] The following is further described in detail through specific implementation methods: Embodiment 1, as attached Figure 2 As shown: the self-unloading device of the boom of a flat-top tower crane includes a lifting device installed on a balance arm and a luffing device and a lifting trolley 6 installed on the boom 3. A lifting platform 4 is installed on the lifting trolley 6. The lifting platform 4 spans over the boom 3, and a boom 5 is installed on the top of the lifting platform 4.

[0023] The lifting device includes a lifting mechanism 1 of the tower crane and a rope pulley 7 installed at the top of the boom 3 and the root of the jib 5. A pulley 16 is installed at the top of the jib 5. The lifting wire rope 11 passes through the rope pulley 7 and the pulley 16 from the lifting mechanism 1 and is connected to the hook. The jib 5 is provided with a wire rope clamping device 10, as shown in the attached figure. Figure 5 As shown, the wire rope clamping device 10 is used to fix the lifting wire rope 11 when the lifting trolley 6 changes its amplitude. The wire rope clamping device 10 includes two clamping plates that are clamped on the main chord of the boom 5 by bolt connection. A base 17 is welded on the clamping plate located on the upper side of the boom 5. A plurality of clamping seats are arranged side by side on the base 17. The clamping seats include an upper groove seat 18 and a lower groove seat 19 that are connected by fasteners. The lower groove seat 19 is welded on the base 17. Semicircular grooves are machined on the lower groove seat 19 and the upper groove seat 18. The inner diameter of the semicircular groove is the same as that of the lifting wire rope 11. The upper groove seat 18 and the lower groove seat 19 are cut off 2 mm above and below the center line of the semicircular groove opening, so that the lifting wire rope 11 can be clamped and fixed by bolts after the upper groove seat 18 and the lower groove seat 19 are fastened, and the wire rope will not be deformed or damaged.

[0024] The luffing device includes a luffing mechanism 2 provided on the tower crane, a rope support wheel 7 and a pulley guide device provided on the boom section before the section to be removed, as shown in the attached diagram. Figure 7 As shown, the pulley guide device includes a support rod 24 located below the boom 3, the two ends of the support rod 24 are connected to the lower chord 20 of the boom by bolts and clamps, two ear plates are welded in the middle of the support rod 24, and a guide pulley 8 is fixedly connected between the ear plates by a pin. The luffing wire rope is wound from the luffing mechanism 2 through the original rope support wheel 7 on the first section of the boom 3, the additional rope support wheel 7, and the guide pulley 8 to connect the hoisting trolley 6.

[0025] As shown in the attached Figure 3 figure, the hoisting platform 4 includes two trapezoidal platform frames 12. The two platform frames 12 are trapezoidally arranged above the boom 3. At the top ends of the two platform frames 12, there are front and rear connecting lifting lugs 13 respectively. At the bottom ends of the two platform frames 12, there are front and rear ear seats respectively. At the front and rear ends as well as in the middle of the top ends of the two platform frames 12, there are two horizontal ear plates 15 and one vertical ear plate 25 respectively. A leveling bolt 14 is connected between the horizontal ear plates 15 and the vertical ear plate 25 at the top ends of the two platform frames 12. The ear seats at the bottom ends of the platform frames 12 are connected to the hoisting trolley 6 through pin shafts.

[0026] As shown in the attached Figure 4 figure, the boom 5 is a lattice type regular triangular cross-section member with a length of 8m. At the front and rear ends of the bottom of the boom 5, there are lifting lugs. The front lifting lug is rotationally connected to the connecting lifting lug 13 of the hoisting platform 4 through a pin shaft. An adjusting bolt 9 is connected between the rear lifting lug and the connecting lifting lug 13 of the hoisting platform 4. The adjusting bolt 9 is used to adjust the elevation angle of the boom 5 between 37° and 55°, so that the corresponding horizontal hoisting distance is from 6.2m to 4.4m, and the corresponding hoisting height is from 4.9m to 6.5m (calculated based on the front connecting lifting lug 13). The leveling bolt 14 can be finely adjusted and positioned when the machining accuracy of the hoisting platform 4 is insufficient to ensure that the levelness of the working surface of the hoisting platform 4 does not exceed 2‰.

[0027] An anti - lifting device is installed on the hoisting trolley 6. As shown in the attached Figure 6 figure, the anti - lifting device includes limit wheel sets located at the front and rear ends of the hoisting trolley 6. The limit wheel sets include rollers 22 and two structural plates 23. The two structural plates 23 are attached to the cross bar 21 of the hoisting trolley 6 from the inner and outer sides. The two structural plates 23 are connected and fixed by three groups of vertically arranged fastening bolts, so that the two structural plates 23 clamp the outside of the cross bar 21 of the hoisting trolley 6 and are vertically supported by the middle fastening bolt. The roller 22 is rotationally connected to the outside of the structural plate 23 through a pin shaft and a bearing, and the roller 22 contacts the bottom of the lower chord of the boom 20.

[0028] Embodiment 2, the self - unloading method of the boom 3 of a flat - top tower crane, includes: Step 1, use the luffing device to luff the hoisting trolley 6 to the previous boom section of the section to be demolished, so that the hook of the boom 5 is located at the center of gravity position of the section to be demolished. The center of gravity of the section to be demolished is at the center position of the boom section. The section to be demolished is always the remaining boom section on the boom 3 that is the farthest from the root of the boom 3. Taking Figure 2 as an example, the boom to be disassembled is divided into 10 boom sections, which are named in sequence from the boom section close to the root of the boom, named ① - ② - ③ - ④ - ⑤ - ⑥ - ⑦ - ⑧ - ⑨ - ⑩ respectively. The boom section at the tip of the boom corresponds to Figure 2In ⑩ thereof, the arm segment ⑩ is called the penultimate segment. The arm segment before the tipmost arm segment ⑩ is the arm segment ⑨, and the arm segment ⑨ is the second to last segment; Step 2: Use the hoisting wire rope 11 to tie the segment to be demolished, start the hoisting mechanism 1 to make it bear the force, remove the connecting pin or bolt between the segment to be demolished and the previous arm segment, and start the hoisting mechanism 1 to lift the segment to be demolished; Step 3: Use the wire rope clamping device 10 on the boom 5 to clamp and fix the hoisting wire rope 11, and make the hoisting trolley 6 move towards the root of the boom 3 through the luffing device. The hoisting wire rope 11 will slack and slide down, and the hoisting wire rope 11 will be recovered synchronously. Personnel stand in the trolley maintenance basket and pay attention to observe to avoid the hoisting wire rope 11 hooking; Step 4: The trolley moves to the interior of the building, slowly recover the hoisting wire rope 11 until it is in a taut state, loosen the wire rope clamping device 10 to make the hoisting wire rope 11 in a usable state, start the hoisting mechanism 1, and place the segment to be demolished on the roof to ensure that it is within the hoisting range of the roof crane; Step 5: At this time, the demolition of one boom segment 3 is completed, and the segment to be demolished becomes the remaining arm segment on the boom 3 and the one farthest from the root of the boom 3; Taking the demolition of the arm segment ⑩, the penultimate segment at the tip, as an example, the segment to be demolished becomes the second to last segment at the tip (i.e., the arm segment ⑨), and transfer the supporting rope wheel 7 and the pulley guiding device of the luffing device to the third to last segment at the tip (i.e., the arm segment ⑧). Before completion, the hoisting trolley 6 should remain in a stopped state, and the hoisting device cannot operate. When the hoisting trolley 6 slowly walks towards the tip of the boom 3, the hoisting wire rope 11 should be released synchronously. Pay attention to the hook of the boom 5 hitting the top. After debugging the luffing device, the demolition of the next boom segment 3 can be started; Step 6: Repeat the above Steps 1 to 5.

[0029] Between Step 2 and Step 4, the roller 22 of the anti-lifting device abuts against the lower chord 20 of the boom to prevent the hoisting trolley 6 from lifting and tilting.

[0030] The background of this embodiment is an internal climbing and external hanging tower crane. Further, in a limited space, auxiliary demolition equipment such as a truck crane cannot be effectively deployed for construction, and this invention is also applicable.

[0031] The above are only embodiments of the present invention. Specific technical solutions and / or common knowledge such as characteristics well known in the art are not described in detail here. It should be noted that for those skilled in the art, without departing from the technical solution of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the implementation effect of the present invention and the practicability of the patent. The protection scope required by this application should be based on the content of its claims, and the specific implementation manners described in the specification can be used to interpret the content of the claims.

Claims

1. Flat-top tower crane boom self-unloading device, including a hoisting device installed on the counter jib and a luffing device and a trolley installed on the boom, characterized in that: A lifting platform is installed on the lifting trolley, the lifting platform spans over the lifting arm, and a lifting arm is installed on the top of the lifting platform; The lifting device includes the lifting mechanism of the tower crane and the rope pulleys at the top of the boom and the root of the boom. A pulley is provided at the top of the boom, and a wire rope clamping device is provided on the boom. The lifting wire rope passes through the rope pulley and the pulley from the lifting mechanism in sequence and is connected to a hook. The luffing device includes the luffing mechanism of the tower crane and the rope support wheel and pulley guide device installed on the boom section before the section to be removed. The luffing wire rope is wound from the luffing mechanism through the original rope support wheel on the first section of the boom, the additional rope support wheel, and the pulley guide device to connect the hoisting trolley; The hoisting platform includes two trapezoidal platform frames, which are arranged above the lifting arm in a trapezoidal shape. The tops of the two platform frames are provided with a plurality of connecting ears, and the bottoms of the two platform frames are provided with ear seats. Bolts are connected between the connecting ears of the two platform frames, and the lifting arm is also connected to the connecting ears. The ear seats are connected to the lifting trolley through a pin shaft. The boom is an 8m long lattice-type equilateral triangular cross-section member. Lifting ears are provided at both the front and rear ends of the bottom of the boom. The front lifting ear is rotatably connected to the connecting lifting ear of the lifting platform, and the rear lifting ear is connected to the connecting lifting ear of the lifting platform by an adjusting bolt. The adjusting bolt is used to adjust the boom elevation angle between 37°-55°.

2. The flat-headed tower crane boom self-unloading device according to claim 1, characterized in that: The lifting trolley is provided with an anti-lifting device, which includes a limiting wheel group located at the front and rear ends of the lifting trolley, and the limiting wheel group includes a roller and two structural plates. The two structural plates are abutted against the cross bar of the lifting trolley from the inside and outside, and the two structural plates are connected and fixed by fasteners. The roller is rotatably connected to the outside of the structural plate, and the roller is in contact with the bottom of the lower chord of the crane arm.

3. The flat-headed tower crane boom self-unloading device according to claim 2, characterized in that: The pulley guide device comprises a support rod located below the boom, two ends of the support rod are connected to the lower chord of the boom, and a guide pulley is fixedly connected to the middle of the support rod.

4. The flat-head tower crane boom self-unloading device according to claim 3, characterized in that: The wire rope clamping device is used to fix the lifting wire rope when the lifting trolley changes its length. The wire rope clamping device includes a base connected to the main chord of the boom with fasteners. A plurality of clamping seats are arranged side by side on the base. The clamping seats include an upper groove seat and a lower groove seat that are buckled and connected with fasteners.

5. The self-unloading method of the flat-top tower crane boom is realized by using the self-unloading device of the flat-top tower crane boom described in any one of claims 1-4, and is characterized in that: include: Step 1: luff the trolley to the boom section before the section to be removed by means of the luffing device, so that the boom hook is located at the center of gravity of the section to be removed; Step 2: Use the lifting wire rope to tie the section to be removed, start the lifting mechanism to make it hold force, remove the connecting pin or bolt between the section to be removed and the previous arm section, start the lifting mechanism, and lift the section to be removed; Step 3: Use the wire rope clamping device on the boom to fix the lifting wire rope, use the luffing device to move the lifting trolley toward the root of the boom, and retract the lifting wire rope synchronously; Step 4: Move the trolley to the interior of the building, retract the lifting wire rope to a taut state, loosen the wire rope clamping device to make the lifting wire rope usable, start the lifting mechanism, and place the section to be removed onto the roof; Step 5: At this time, one section of the boom is removed, and the section to be removed becomes the remaining section on the boom and the farthest from the root of the boom; Step 6: Repeat steps 1 to 5 above.

6. The self-unloading method for the boom of a flat-headed tower crane according to claim 5, characterized in that: Between Step 2 and Step 4, the roller of the anti-head-up device abuts against the lower chord of the boom to prevent the hoisting trolley from tilting with its head up.

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