JP5331539B2 - Derrick for steel tower assembly and dismantling - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily raise and fall a boom without increasing a winding load when the boom is raised in the lifted state of a hoisted cargo. <P>SOLUTION: In this derrick, the boom having one end mounted to a mast vertically and temporarily fixed to an upper end of an iron tower is provided so as to be freely raised and fallen, a lifting wire rope having a hook at a lower end is drawn down from a pulley at a tip of the boom, the other end of the lifting wire rope is laid on a pulley in an upper part of the mast, and the hoisted cargo is lifted up and lifted down by operating the lifting wire rope on a lower side of the mast. The mast 2 is formed into a cylindrical shape and supported to a member of the iron tower 20 to be rotatable in a peripheral direction, and a top pulley 23 is provided in an upper part of the mast 2. A tip pulley 22 is journaled to a bearing frame 22a provided at a tip of the boom 3. One end of the lifting wire rope 8 is laid over each of the tip pulley 22 and the top pulley 23. A stopper 7a lockable to the bearing frame 22a is provided on a hook at the other end of the lifting wire rope 8. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a derrick for assembling and dismantling a steel tower for use in assembling and dismantling a steel tower.

  An apparatus and method for assembling / disassembling a steel tower is disclosed in Patent Document 1. This apparatus attaches a pedestal to a steel tower, removes it after assembly, and sequentially moves the pedestal above the steel tower. However, in the apparatus of Patent Document 1, it is troublesome to attach and remove the pedestal to the steel tower, and it is difficult to perform the operation quickly.

  Therefore, as shown in FIG. 9, the applicant of the present application has a cylindrical mast 2, a rod-like boom 3 having one end rotatably attached to the mast 2 in the circumferential direction, and the mast 2. Ring-shaped mast guides 4 and 5 that can be inserted through the outer side of the mast 2, and a mast base 6 that continuously protrudes from the outer peripheral side of the mast 2. The mast 2 is cut at the position of the turning member 14, the upper mast 2 a can be rotated together with the turning member 14, and a lifting wire rope 8 is attached to the tip of the boom 3. The lifting wire rope 8 is passed through the guide roller 9 provided on the upper side of the swiveling member 14 into the mast 2, and the lifting wire rope 8 is operated from the lower side of the mast 2. You Thus, the hook 7 can move up and down, and one end of the undulation wire 11 is attached near the tip of the boom 3, and the undulation wire 11 is provided on the upper end of the mast 2. The other end of the undulation wire 11 is fixed to the mast 2 so as to be rotatable in the circumferential direction, and the boom 3 is adjusted by adjusting the length of the undulation wire 11. The mast guides 4, 5, and the mast base 6 have fixed ropes 16, 17, 18 for fixing to the main material 19 of the tower 20. The steel tower assembly / disassembly derrick 1 was developed in which the mast base 6 is connected to the mast base 6 and fixed to the main material 19 of the steel tower 20 and connected to a hoisting tool 21 that can be rolled up.

  The derrick 1 for assembling / disassembling the steel tower uses two wires, a boom hoisting wire 11 for changing the position of the suspended load and a lifting wire rope 8 for lifting and lowering the suspended load. The hoisting wire rope 8 is lowered to the ground through the mast and wound with a winch. However, the hoisting wire 11 is entangled with the hoisting wire rope 8 when the boom 3 is turned and cannot be turned. It was.

JP 2005-68864 A

  However, in the steel tower assembly / disassembly derrick 1 of FIG. 9, when the boom 3 is raised in a state where a suspended load such as a steel tower member is lifted, the winding load of the undulating wire 11 becomes large, so that it takes time to operate the winding device. And labor was required. Further, when the boom 3 is raised by winding the hoisting wire 11, as shown in FIG. 10A, when the boom 3 approaches an upright state, the load in the direction to raise the boom 3 becomes larger than the suspended load. The boom 3 was suddenly raised, and the mast 2 and the like were shocked by the suspended load, which was dangerous. Further, as shown in FIG. 10B, when there is no suspended load in the upright boom 3, even if the hoisting wire 11 is loosened, the boom 3 cannot be lowered by its own weight. It was necessary to pull down the operation rope 10 from the ground, and the operation was troublesome.

  The present invention is based on such a prior art, and provides a derrick for assembling and dismantling a steel tower in which the winding load does not increase when the boom is raised with a suspended load lifted, and the boom can be easily raised and lowered. It is for the purpose.

Accordingly, the invention of claim 1 provides a mast that is temporarily fixed to the upper end of a steel tower that is being assembled or dismantled, and has a boom that has one end that can be raised and lowered, and is hooked from the pulley at the tip of the boom to the lower end. In a derrick that lowers a lifting wire rope having the other end, hangs the other end of the lifting wire rope on a pulley at the top of the mast, and operates the lifting wire rope below the mast to lift or suspend the load. As a temporary fixing to the member of the upper end of the steel tower to enable circumferential rotation, a top pulley is provided at the top of the mast, a tip pulley supported by a bearing frame provided at the tip of the boom is provided, One end of the lifting wire rope is hung on the tip pulley in the bearing frame at the tip of the boom and the top pulley of the mast, and is passed through the mast. Is guided downwards, the lifting of the stopper provided at the base end of the hook provided at the other end of the wire rope, the stopper is to freely engaging said lifting and pulling the wire rope to the bearing frame of the tip pulley, of the boom The other end of the undulation lock linear body having one end fixed to the intermediate portion is hung down on the undulation lock pulley provided on the mast below the top pulley, and a number of engagements provided in the vertical direction on the mast. It is possible to lock to one of the stops, adjust the length of the undulation lock linear body from the boom to the undulation lock pulley, and set up a derrick for steel tower assembly / disassembly with a undulation lock device that can be fixed .

According to a second aspect of the present invention , there is provided a boom having one end that is undulated and attached to a mast that is temporarily fixed vertically to an upper end of a steel tower that is being assembled or disassembled, and a hook that is hooked at a lower end from a pulley at the tip of the boom. In a derrick that lowers a lifting wire rope having the other end, hangs the other end of the lifting wire rope on a pulley at the top of the mast, and operates the lifting wire rope below the mast to lift or suspend the load. Temporarily fixed to the member at the upper end of the steel tower to enable circumferential rotation, provided with a top pulley at the top of the mast, provided with a tip pulley supported by a bearing frame provided at the tip of the boom, One end of the lifting wire rope is hung on the tip pulley in the bearing frame at the tip of the boom and the top pulley of the mast, and is passed through the mast and under the mast. Is derived, the lifting of the stopper provided at the base end of the hook provided at the other end of the wire rope, the stopper, the lifting and freely engaging the bearing frame of the tip sheaves and pulling a wire rope, an intermediate of the boom The other end of the undulation lock linear body with one end fixed to the part is hung down on the undulation lock pulley provided on the mast below the top pulley, and the hoist with a ratchet claw provided on the mast The steel tower assembly / disassembly derrick is provided with a undulating lock device that can be fixed by adjusting the length of the undulating lock wire from the boom to the undulating lock pulley.

According to a third aspect of the present invention, there is provided a boom holding pipe that covers a lifting wire rope between the top pulley of the mast and the tip pulley of the boom, and the boom holding pipe has a butt end of each of the plurality of short pipes. The other short pipe is inserted into one short pipe and is connected to be stretchable in the length direction, and one end of the short pipe close to the top pulley of these short pipes is perpendicular to the bearing of the top pulley. The end of the short pipe close to the tip pulley of the boom is attached to the bearing frame of the tip pulley so as to be freely rotatable in the vertical direction so that the boom holding pipe composed of these short pipes always extends in the longitudinal direction. The derrick for steel tower assembly / disassembly according to claim 1 or 2 , wherein an urged spring spring is provided in the boom holding pipe .

According to the first and second aspects of the present invention, in the state where the suspended load is lifted up to the tip of the boom by the lifting wire rope suspended from the tip of the boom, the stopper at the base of the hook of the lifting wire rope is engaged with the bearing frame of the tip pulley. When it is stopped and the hoisting wire rope is wound up from the ground with a winch or the like, the boom rises with respect to the mast. Therefore, it is possible to lift and suspend a suspended load and raise and lower a boom with a single lifting wire rope. Also, when raising the boom with respect to the mast, it is only necessary to wind up the wire rope from the ground with a winch or the like, and the winding load does not increase, and the boom can be easily raised and lowered.

Further, in addition to the effect of the invention of the above-mentioned claim , since the hoisting lock device is provided, when the boom is raised or lowered with respect to the mast by winding or unwinding the lifting wire rope, the hoisting lock wire of the hoisting lock device is used. It is necessary to remove the latch or ratchet pawl, but when the boom is stopped at any undulation location, if the undulation lock filament is loosened by the undulation, the undulation lock filament is tensioned. In this state, it can be easily and reliably locked and is safe.

  Further, in the invention of claim 3, in addition to the effect of the invention of the above-mentioned claim, when the boom is raised while hanging the suspended load, the load in the direction of raising the boom by the lifting wire rope increases when the boom is close to the upright position. The boom suddenly rises and a large impact occurs, which is dangerous, but the boom can be prevented from rising suddenly by the repulsive load of the spring spring provided on the outer periphery of the boom holding pipe. In addition, since an empty boom that is occurring near the upright can be lowered with the force of the spring spring of the boom holding pipe, the boom can be easily lowered without using an operation rope from the ground as in the past. So it is efficient.

  The present invention provides a lifting wire rope having a boom that is temporarily fixed to the upper end of a steel tower in the middle of assembly or dismantling, with a boom attached at one end to be raised and lowered, and a hook at the lower end from the pulley at the tip of the boom. In the derrick, the other end of the lifting wire rope is hung on the pulley at the upper part of the mast and the lifting wire rope is operated below the mast to lift or suspend the suspended load. Temporarily fixed to the member of the part so as to be able to rotate in the circumferential direction, provided with a top pulley at the top of the mast, provided with a tip pulley supported by a bearing frame provided at the tip of the boom, One end is hung on the tip pulley in the bearing frame of the boom tip and the top pulley of the mast, and is passed through the mast and led out below the mast. A steel tower assembly / disassembly derrick is provided with a stopper at the base end of the hook provided at the other end of the lifting wire rope, and the stopper can be locked to the bearing frame of the tip pulley when the lifting wire rope is pulled up. It was.

Embodiment 1 of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic front view of a derrick for steel tower assembly / disassembly according to the present invention, and FIG. 2 is an enlarged front view of a main part of the present invention.

  As shown in the figure, a derrick 1 for assembling and dismantling a steel tower according to the present invention includes a mast 2, a boom 3, mast guides 4 and 5, and a mast base 6. The mast 2 has a cylindrical shape, and the upper end and the lower end communicate with each other. The boom 3 has a rod shape, and is attached to the mast 2 so as to be rotatable in the vertical direction at a base end portion 3a which is one end portion. The mast guides 4 and 5 are ring-shaped and are provided through the mast 2. The mast base 6 is provided at the lower end of the mast 2 and is continuously projected from the outer peripheral side of the mast 2. The outer shape of the mast base 6 is substantially the same as the mast guides 4 and 5.

  The boom 3 is attached to the mast 2 so as to be rotatable in the vertical direction at the base end portion 3a. A bearing frame 22a is attached to the tip of the boom 3, and a tip pulley 22 is pivotally supported on the bearing frame 22a. Then, the lifting wire rope 8 is passed through the bearing frame 22 a and hooked to the tip pulley 22, and one end thereof is led out from the bearing frame 22 a and connected to the hook 7. A stopper 7a is formed at the base of the hook 7, and when the lifting wire rope 8 is pulled upward, the stopper 7a is hooked on the bearing frame 22a. Therefore, when the lifting wire rope 8 is pulled up further, the boom 3 rotates vertically around the base end portion 3a, and the boom 3 is raised.

  A top pulley 23 is provided at the top of the mast 2, and the other end of the lifting wire rope 8 is hooked on the top pulley 23 and passed through the mast 2. The lifting wire rope 8 passed through the mast 2 is exposed from the lower end of the mast 2 and fixed to a drum of a winch (not shown) provided on the ground, and the winding wire rope 8 is wound and fed out by this winch. Is possible. If the hoisting wire rope 8 is wound up, the hook 7 rises, and if it is drawn out, the hook 7 descends. When the lifting wire rope 8 is wound up and the stopper 7a of the hook 7 is hooked on the bearing frame 22a, the boom 3 rises as it is, and when the lifting wire rope 8 is unwound, the boom 3 has a base end 3a. Rotate downwards around the center and lie down.

  The mast guides 4 and 5 and the mast base 6 are fixed to the four main members 19 of the steel tower 20 via fixed ropes 16, 17 and 18, respectively. In this way, the mast base 6 at the lower end of the mast 2 is fixed to the steel tower 20, and the mast 2 is fixed to the steel tower 20 while being supported by the mast guides 4, 5. The shaft is securely held without shaking. Therefore, when assembling the steel tower by operating the boom 3, it is possible to work safely.

  Further, according to the assembly of the steel tower 20, the mast 2 is moved to the upper end portion of the mast 2 being assembled. In this case, four main ropes of each fixed rope 18 supporting the mast base 6 are used. Unfastening the material 19, fixing one end of each lifting tool 21 to the mast base 6, fixing the other end to the upper part of the main material 19, and even operating the winch provided for each lifting tool 21 Then, the mast base 6 is moved upward.

  FIG. 3 is a schematic view of the boom 3. As shown in the figure, the boom 3 is formed by overlapping two plate members 3c and 3c having a step portion 3b symmetrically. Therefore, one end of the boom 3 is divided into two forks, and this end becomes the base end 3a, and the mast 2 is sandwiched and supported by the base end 3a. The other end is provided with the bearing frame 22a and the tip pulley 22. Further, a support 24 is provided between the middle plate 2c and 3c in the middle of the boom 3, and a bottom-type cover frame 25 is provided from the tip of the boom 3 to the middle. Yes.

  The distance L between the base end portion 3a and the stepped portion 3b is substantially the same as the distance between the mounting position of the boom 3 in the mast 2 and the upper end of the mast 2 including the top pulley 23. Thereby, the boom 3 can be raised until the axis of the boom 3 and the axis of the mast 2 are matched.

  Further, the lower end of the mast 2 is attached to the mast base 6. However, as shown in FIG. 4, a bearing is provided on the mast base 6 so that the mast 2 can be rotated in the circumferential direction of the mast 2. Yes. Accordingly, the swiveling lever 26 fixed to the outer periphery of the mast 2 is raised, and the mast 2 is rotated in the circumferential direction by placing the hand on the lever 26, so that the horizontal position of the boom 3 can be changed.

  Further, the lifting wire rope 8 between the tip pulley 22 and the top pulley 23 is covered with a boom holding pipe 27 as shown in FIG. The boom holding pipe 27 is urged so as to extend in the longitudinal direction by a spring spring 28 provided on the outer periphery thereof. Therefore, the boom 3 is always pressed to be in a substantially horizontal position shown in FIGS. .

  As shown in FIG. 5, the boom holding pipe 27 is telescopic in the length direction by inserting the butted ends of the three short pipes 27a and inserting the other short pipe 27a into one short pipe 27a. One end of the short pipe 27 close to the top pulley 23 of these short pipes 27a is bifurcated and attached to the axis of the top pulley 23 so as to be vertically rotatable, and attached to the tip pulley 22 of the boom 3 One end of the near short pipe 27a is attached to the bearing frame 22a of the tip pulley 22 so as to be rotatable in the vertical direction, and each end is fixed to the outer periphery of the two short pipes 27a located at both ends thereof, and is attached to extend in the longitudinal direction. A biased spring spring 28 is provided.

  As described above, the lifting wire rope 8 is wound from the ground with a winch or the like, the stopper 7a of the hook 7 hits the bearing frame 22a, and the tip of the boom 3 rotates upward. At this time, the boom holding pipe 27 is Shrinks against the force of the spring spring 28. When the boom 3 is rotated so as to be lowered, the boom holding pipe 27 extends in the longitudinal direction by the force of the spring spring 28.

  Therefore, when the lifting wire rope 8 is pulled from below the mast 2, the boom 3 is raised. However, when the tip approaches the mast 2 and approaches the upright state, the load in the direction in which the boom 3 is raised by the lifting wire rope 8 increases and suddenly increases. The boom 3 can be prevented from abruptly rising due to the repulsive load of the spring spring 28 provided on the outer periphery of the boom holding pipe 27. In addition, when the empty boom 3 that is standing upright is lowered, the force of the boom holding pipe 28 is extended in the longitudinal direction by the force of the spring spring 28 of the boom holding pipe 27, and the boom 3 can be easily lowered. Can do.

  Further, the steel tower assembly / disassembly derrick 1 is provided with a hoisting lock device 30 for locking the boom 3 at an arbitrary position of the hoisting of the boom 3. As shown in FIG. 6, the undulation locking device 30 includes a vertically long rectangular tube case 30 a and is provided on the mast 2 below the top pulley 23. A fixed sprocket 31 is pivotally supported on the mast 2 above the undulating lock device 30. A movable sprocket 32 that moves up and down in a substantially vertical direction inside the case 30a of the undulation lock device 30 below the fixed sprocket 31 is provided, and the other end of the stopper chain 33 having one end fixed to the support 24 of the boom 3 is The fixed sprocket 31 is hung from above and lowered downward, and is hung on the lower part of the movable sprocket 32 and directed upward, and fixed to the mast 2 below the fixed sprocket 31.

  The movable sprocket 32 is rotatably supported on an upper portion of a movable frame 34 that is movable only in the vertical direction within the case 30a. A shaft 35 is provided at the lower portion of the movable frame 34, and two links 36 with claws having claws at one end intersect with each other at the shaft 35, and are supported symmetrically around the shaft 35. . The upper portions of the links 37, 37 are pivotally supported at the lower ends of the links 36 with the claws, the lower ends of the links 37 are pivotally supported by the shaft 38, and one end of the operation rope 39 is fixed to the shaft 38, The other end of the operation rope 39 is fixed to a lever lock 40 provided on the outer periphery of the lower mast 2.

  Further, springs 41 are respectively provided between the lower portions of the links 36 with the claws and the movable frame 34, and the tips of the links 36 with the claws are always urged to open in the left-right direction. On the other hand, in the case 30a, as shown in FIG. 8, a large number of locking holes 42 are regularly provided in opposite side plates, and the claw of each of the two clawed links 36 has these locking holes 42. The claw at the tip of each claw link 36 is always fitted into one of the locking holes 42 by the force of the spring 41.

  Then, when the lever block 40 provided on the mast 2 is unwound and the operating rope 39 is pulled downward against the force of the spring 41 as shown in FIG. The claw is disengaged from the left and right engaging holes 42 of the case 30a, and the movable frame 34 can be moved downward in the case 30a while pulling the operation rope 29 downward in this state. When the boom 3 is tilted, the stopper chain 33 is fed out by the force of the boom holding pipe 27 extending in the longitudinal direction and the weight of the boom 3, and the movable frame 34 pulls the operation rope 29 downward. Can move upward in the state. The movable frame 34 is restricted from moving upward by a stopper body 43 provided at the upper end of the case 30a.

  With the hoisting and locking device 30, the operation chain 39 is operated at the position where the hoisting operation of the boom 3 is stopped, and the stopper chain 33 between the boom 3 and the mast 2 is tensioned and locked.

  The undulating lock device 30 and the stopper chain 33 are not limited to those in the above embodiment. For example, instead of the stopper chain, an appropriate undulation locking wire body may be used. Further, the other end of the undulation-locking linear body having one end fixed to the middle of the boom 3 is fixed to a hoisting machine with a ratchet claw provided on the mast 2, and the undulation-locking linear body is fixed by a hoisting machine. It is good also as an undulation | locking device of the structure wound up.

It is a schematic front view of Example 1 of this invention. It is a principal part enlarged front view of Example 1 of this invention. It is an enlarged view of the boom of Example 1 of this invention, (A) A figure is a top view, (B) A figure is a front view. It is an enlarged front view of the mast base of Example 1 of this invention. It is an exploded view of the boom pressing pipe of Example 1 of this invention. It is a longitudinal cross-sectional view of the locked state of the undulation locking device of Example 1 of this invention. It is a longitudinal cross-sectional view of the state which canceled the lock | rock of the undulation locking apparatus of Example 1 of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing of the case of the raising / lowering locking apparatus of Example 1 of this invention, (A) A figure is a side view, (B) is a front view, (C) is a top view. It is a front view of a prior art example. FIGS. 2A and 2B are explanatory diagrams for use in the conventional example.

DESCRIPTION OF SYMBOLS 1 Derrick for steel tower assembly and dismantling 2 Mast 3 Boom 3a Base end part 3b Step part 3c Plate material 4 Mast guide 5 Mast guide 6 Mast base 7 Hook 7a Stopper 8 Lifting wire rope
DESCRIPTION OF SYMBOLS 16 Fixed rope 17 Cottage rope 18 Fixed rope 19 Main material 20 Steel tower 21 Lifting tool 22 Tip pulley 22a Bearing frame 23 Top pulley 24 Support body 25 Cover frame 26 Swivel lever 27 Boom holding pipe 28 Spring spring 30 Undulating lock device 31 Fixed sprocket 32 Movable sprocket 33 Stopper chain 34 Movable frame 35 Shaft 36 Lick with tab 37 Link 38 Shaft 39 Operation rope 40 Lever lock 41 Spring 42 Locking hole 45 Stopper body

Claims (3)

A boom with one end attached to the mast that is temporarily fixed vertically to the upper end of the steel tower during assembly or disassembly is provided, and a lifting wire rope having a hook at the lower end is lowered from the pulley at the tip of the boom. In the derrick where the other end of the lifting wire rope is hung on the pulley at the top of the mast, and the lifting wire rope is lifted or suspended by operating the lifting wire rope below the mast.
Temporarily fixing the mast as a cylinder to the member at the upper end of the steel tower, allowing circumferential rotation,
A top pulley is provided at the top of the mast,
A tip pulley supported by a bearing frame provided at the tip of the boom is provided;
One end of the hoisting wire rope is hung on the top pulley in the bearing frame at the tip of the boom and the top pulley of the mast, respectively, passed through the mast and led to the lower side of the mast,
A stopper is provided at the proximal end of the hook provided at the other end of the lifting wire rope, and the stopper can be locked to the bearing frame of the tip pulley when the lifting wire rope is pulled up,
The other end of the hoisting lock linear body having one end fixed to the middle part of the boom is hung down on the hoisting lock pulley provided on the mast below the top pulley, and is provided vertically on the mast. It is possible to engage with one of a large number of engaging parts, and adjust the length of the undulation lock linear member from the boom to the undulation lock pulley, and a fixed undulation lock device is provided. , Derrick for steel tower assembly and dismantling. A boom with one end attached to the mast that is temporarily fixed vertically to the upper end of the steel tower during assembly or disassembly is provided, and a lifting wire rope having a hook at the lower end is lowered from the pulley at the tip of the boom. In the derrick where the other end of the lifting wire rope is hung on the pulley at the top of the mast, and the lifting wire rope is lifted or suspended by operating the lifting wire rope below the mast.
Temporarily fixing the mast as a cylinder to the member at the upper end of the steel tower, allowing circumferential rotation,
A top pulley is provided at the top of the mast,
A tip pulley supported by a bearing frame provided at the tip of the boom is provided;
One end of the hoisting wire rope is hung on the top pulley in the bearing frame at the tip of the boom and the top pulley of the mast, respectively, passed through the mast and led to the lower side of the mast,
A stopper is provided at the proximal end of the hook provided at the other end of the lifting wire rope, and the stopper can be locked to the bearing frame of the tip pulley when the lifting wire rope is pulled up,
With the ratchet pawl provided on the mast, the other end of the undulation locking linear body fixed at one end to the middle part of the boom is hung down on the hoisting lock pulley provided on the mast below the top pulley. A derrick for assembling and dismantling steel towers, characterized in that it is fixed to a hoisting machine, adjusts the length of the wire rod for hoisting lock from the boom to the pulley for hoisting lock, and is provided with a hoisting lock device that can be fixed freely . A boom holding pipe covering a lifting wire rope between the top pulley of the mast and the tip pulley of the boom is provided, and the boom holding pipe has a butt end of each of the plurality of short pipes in one short pipe. Insert short pipes and connect them in such a way that they can be stretched in the length direction, and attach the ends of the short pipes close to the top pulley of these short pipes to the bearings of the top pulley so that they can rotate in the vertical direction. One end of a short pipe close to the pulley is rotatably attached to the bearing frame of the tip pulley in the vertical direction, and a spring spring that is biased so that a boom holding pipe composed of these short pipes always extends in the longitudinal direction is attached to the boom. The derrick for steel tower assembling / disassembling according to any one of claims 1 and 2 , wherein the derrick is provided on a holding pipe .

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