Self-balancing A-frame pole

Abstract

This application discloses a self-balancing A-frame derrick, including a derrick head, a pair of derrick arms, a pair of guy lines, and a pair of derrick feet. The derrick head includes a hinged lifting lug for lifting heavy objects and connecting the guy lines. The top ends of the derrick arms are hinged to the derrick head, and the bottom ends of the derrick arms are hinged to the derrick feet. During drop-lifting, the derrick arms are adapted to deflect around the hinged position of the derrick feet, thereby driving the lifting lugs to deflect around the hinged position, and thus balancing the overturning force generated by the weight of the lifted object through the tension of the guy lines. The beneficial effect of this application is that force balance can be automatically achieved through the self-deflection of the derrick arms and the lifting lugs, ensuring that the derrick arms are only subjected to compressive forces along their own axis, thereby preventing the derrick arms from overturning or bending, and thus effectively improving the safety of using the A-frame derrick.

Description

Technical Field

[0001] This application relates to the field of engineering construction technology, and in particular to a type of A-frame derrick. Background Technology

[0002] A-frame derrick, also known as an A-frame boom, is a simple lifting device commonly used in lifting operations. It is mainly used for lifting lightweight objects or as an accessory to erect large components by falling.

[0003] Existing A-frame derricks mainly consist of a derrick head, a pair of derrick arms, a pair of guy lines, and a pair of derrick feet. The two derrick arms are hinged to the sides of the derrick head at their top ends, and the derrick feet are fixed to the bottom of their respective derrick arms. When lifting objects, the two derrick arms are fixed to the ground in an A-shape via the derrick feet, and the guy lines are also fixed to the sides of the derrick head at their top ends, ensuring that the plane formed by the two guy lines is perpendicular to the plane formed by the two derrick arms. The object is then lifted directly below the derrick head. However, in drop-lift installations, since the center of gravity of the object is not necessarily directly below the derrick head, the derrick arms may shift and experience bending moments under the component of the object's weight, potentially causing the derrick arms to overturn or bend, leading to an accident. Summary of the Invention

[0004] One of the objectives of this application is to provide an A-frame derrick capable of automatically balancing the bending moment of the derrick arm.

[0005] To achieve the above objectives, the technical solution adopted in this application is as follows: a self-balancing A-frame derrick, comprising a derrick head, a pair of derrick arms, a pair of guy lines, and a pair of derrick feet; the derrick head includes a hinged lifting lug for lifting objects and connecting the guy lines; the top end of each derrick arm is hinged to the derrick head, and the bottom end of each derrick arm is hinged to the derrick feet; during drop-lifting, the derrick arms are adapted to deflect around the hinged position of the derrick feet, thereby driving the lifting lugs to deflect around the hinged position, and thus balancing the overturning force generated by the weight of the lifted object through the tension of the guy lines. This ensures that the derrick arms are only subjected to axial compressive force.

[0006] Preferably, the derrick head includes a connecting assembly and a lifting lug, the two derrick arms are respectively hinged to both sides of the connecting assembly, the lifting lug is hinged to the middle of the connecting assembly, and the rotation plane of the lifting lug is perpendicular to the rotation plane of the derrick arm around the connecting assembly.

[0007] Preferably, the connecting assembly includes a pair of ear plates, which are detachably connected by a plurality of fasteners to facilitate the installation of the lifting lug; the lifting lug is hinged between the ear plates by fasteners; the derrick arm is correspondingly hinged to the side of the ear plates.

[0008] Preferably, the ear plate includes a vertical plate and a hinge ear; the two ear plates are detachably connected by the vertical plate; the hinge ear is fixed to the opposite side of the vertical plate, and the top end of the lever arm is hinged to the hinge ear.

[0009] Preferably, the lifting lug includes a weight lug and a pair of mooring lugs; the upper part of the weight lug is hinged to the connecting assembly, and the lower part of the weight lug is used for lifting objects; the mooring lugs are fixedly disposed on both sides of the weight lug for attaching the pull wire.

[0010] Preferably, the midpoint between the top of the boom arm and the hinge position of the connecting component and the midpoint between the lifting lug and the hinge position of the connecting component are collinear in the horizontal direction.

[0011] Preferably, the derrick foot includes a balance beam and a boot seat; the balance beam is hinged to the bottom end of the derrick arm; the boot seat is suitable for fixed installation on the ground, the boot seat is hinged to the balance beam, and the hinge direction of the boot seat and the balance beam is perpendicular to the hinge direction of the balance beam and the bottom end of the derrick arm; thus, the boot seat can maintain stable installation on the ground when the derrick arm is extended and deflected.

[0012] Preferably, the boot base includes a mounting plate and a rotating sleeve fixed to the mounting plate; the balance beam includes a third hinge plate and a support shaft; the boot base is fixedly installed to the ground via the mounting plate, the boot base is hinged to the support shaft via the rotating sleeve, and the balance beam is hinged to the bottom end of the boom arm via the third hinge plate.

[0013] Preferably, the derrick head further includes a pair of upper hinges, and the derrick foot further includes a lower hinge; the upper hinges are respectively hinged to both sides of the connecting assembly, and the lower hinges are hinged to the balance beam; the top end of the derrick arm is fixedly connected to the upper hinges, and the bottom end of the derrick arm is fixedly connected to the lower hinges.

[0014] Preferably, the boom arm includes at least one boom tube, and adjacent boom tubes are detachably fixedly connected by boom sections.

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

[0016] When lifting objects, this application can automatically achieve force balance through the self-deflection of the boom arm and the lifting lug, so as to ensure that the boom arm is only subjected to compressive force along its own axis, thereby avoiding the boom arm from overturning or bending, and thus effectively improving the safety of A-frame boom operation. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0018] Figure 2 This is a schematic diagram of the structure of the pole head in this invention.

[0019] Figure 3 This is a schematic diagram showing the disassembled state of the pole head in this invention.

[0020] Figure 4 This is a schematic diagram of the ear plate in this invention.

[0021] Figure 5 This is a schematic diagram of the upper hinge structure in this invention.

[0022] Figure 6 This is a schematic diagram of the lifting lug structure in this invention.

[0023] Figure 7 This is a schematic diagram of the disassembled state of the boom arm in this invention.

[0024] Figure 8 This is a schematic diagram showing the disassembled state of the pole foot in this invention.

[0025] Figure 9 This is a schematic diagram of the installation state when the present invention is in operation.

[0026] Figure 10 This is a schematic diagram of the force analysis during the initial hoisting of the present invention.

[0027] Figure 11 This is a schematic diagram of the force analysis during the self-balancing process of hoisting according to the present invention.

[0028] In the diagram: 1. Drill head, 11. Ear plate, 111. Hinge ear, 112. Upper support hinge, 121. First hinge plate, 122. Upper connecting sleeve, 13. Lifting ear, 131. Mooring ear, 132. Helmet remover, 14. Drill arm, 21. Drill tube, 22. Drill section, 3. Drill foot, 31. Lower support hinge, 311. Lower connecting sleeve, 312. Second hinge plate, 32. Balance beam, 321. Third hinge plate, 322. Support shaft, 322. Shoe seat, 33. Rotating sleeve, 331. Mounting plate, 332. Guy wire, 4. Detailed Implementation

[0029] The present application will be further described below with reference to specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0030] In the description of this application, it should be noted that the directional terms such as "center", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limiting the specific protection scope of this application.

[0031] It should be noted that the terms "first," "second," etc., in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0032] One preferred embodiment of this application, such as Figures 1 to 11 As shown, a self-balancing A-frame derrick includes a derrick head 1, a pair of derrick arms 2, a pair of guy lines 4, and a pair of derrick feet 3. The top ends of the two derrick arms 2 are hinged to the two sides of the derrick head 1, and the two derrick feet 3 are hinged to the bottom ends of the corresponding derrick arms 2. The derrick head 1 includes hinged lifting lugs 13, and the two guy lines 4 are bolted to the two sides of the lifting lugs 13 through their top ends, so that the plane formed by the two guy lines 4 is perpendicular to the plane formed by the two derrick arms 2; at the same time, the lifting lugs 13 can also be used to lift objects.

[0033] During the drop-lifting operation, the two boom arms 2 are extended in a V-shape and fixed to the ground via boom feet 3; simultaneously, the two guy lines 4 are also taut in a V-shape and fixed to the ground. Then, one end of the rope is secured to the fallen object, and the other end of the rope is passed through the lifting lug 13 to pull the object; as the rope is pulled, the object gradually stands up from its fallen state.

[0034] Furthermore, during the process of erecting the object, the deflection of the boom arm 2 around the hinge position of the boom foot 3 towards the center of gravity of the object drives the lifting lug 13 to deflect around the hinge position. In turn, the tension of the pull line 4 balances the overturning force generated by the weight of the object being lifted, so that the boom arm 2 is only subjected to axial compressive force, thereby preventing the boom arm 2 from overturning or bending, thus effectively improving the safety of the A-frame boom of this application.

[0035] Understandably, due to the drop-lifting method, the center of gravity of the object cannot be directly below the boom arm 2. Therefore, the object's weight can be decomposed into a vertical component and a horizontal component. The vertical component can be decomposed into the axial compressive force of the two boom arms 2, which can then be balanced by the boom feet 3 on the vertical component of the supporting force of the boom arms 2. The horizontal component of the object will exert an overturning force on the boom arms 2 towards the guy wire 4.

[0036] In traditional A-frame derricks, the position of the guy wire 4 is always fixed, and the derrick arm 2 is rigidly connected towards the guy wire 4. This ensures that the horizontal component of the force on the two guy wires 4 is always balanced, which in turn prevents the horizontal component of the force on the object from being balanced. That is, during a drop-lift operation, the derrick arm 2 is always subjected to an overturning moment, and the fulcrum of this moment is located at the derrick foot 3. If the anchoring force between the derrick foot 3 and the ground is sufficient, an excessive overturning moment may cause the derrick arm 2 to bend; if the anchoring force between the derrick foot 3 and the ground is insufficient, an excessive overturning moment may cause the derrick foot 3 to detach from the ground, leading to the overturning of the A-frame derrick.

[0037] Regarding the self-balancing A-frame derrick of this application, self-balancing can occur when the derrick arm 2 is subjected to an overturning force. The specific self-balancing process is as follows: the derrick arm 2 deflects around the derrick foot 3 towards the center of gravity of the object. During this deflection, the lifting lug 13 deflects around its hinged position with the derrick head 1 simultaneously with the derrick arm 2, thus balancing the change in distance between the two guy wires 4 and the lifting lug 13. At this time, because the positions of the two guy wires 4 have changed, the horizontal components of the two guy wires 4 are unequal. That is, the difference in the horizontal components of the two guy wires 4 exactly cancels out the horizontal component of the object, ensuring that the derrick arm 2 is only subjected to compressive force along its own axial direction.

[0038] In this embodiment, as Figure 2 and Figure 3 As shown, the derrick head 1 includes a connecting assembly and a lifting lug 13. Two derrick arms 2 are hinged to both sides of the connecting assembly, and the lifting lug 13 is hinged to the middle of the connecting assembly. This ensures that during hoisting, the vertical component of the object's weight is equal in magnitude to the axial compressive force generated by the two derrick arms 2. The rotation plane of the lifting lug 13 is perpendicular to the rotation plane of the derrick arm 2 around the connecting assembly, ensuring that the deflection of the lifting lug 13 meets the aforementioned self-balancing requirements.

[0039] In this embodiment, there are various structures for the connecting component, one of which is a preferred embodiment, such as... Figure 2 and Figure 3As shown, the connecting assembly includes a pair of ear plates 11, which are detachably connected by multiple fasteners. Therefore, when installing the lifting lug 13, the two ear plates 11 can be disassembled first, and then the lifting lug 13 can be hinged and installed between the ear plates 11 using fasteners. Simultaneously, the boom arm 2 is also hinged to the side of the ear plates 11 using corresponding fasteners.

[0040] Understandably, the number of fasteners can be set according to actual needs, such as 2 and... Figure 3 As shown, the two ear plates 11 are installed in a triangular structure by three fasteners, and the lifting ear 13 is hinged to the lowest fastener.

[0041] Specifically, such as Figure 4 As shown, the ear plate 11 includes a vertical plate 111 and a hinge ear 112. The two ear plates 11 are detachably connected by fasteners through the vertical plate 111. The hinge ear 112 is fixed to the opposite sides of the two vertical plates 111, so that the top end of the derrick arm 2 is hinged through the hinge ear 112.

[0042] Understandably, the fasteners are existing technology, generally bolts. Therefore, when installing the ear plate 11, the bolts can pass through the two upright plates 111, and a pin sleeve is fitted onto the smooth section between the two upright plates 111. This allows the two upright plates 111 to abut against the two ends of the pin sleeve when the bolts are fixed, thus ensuring that a gap is created between the two upright plates 111 for the installation and deflection of the lifting lug 13.

[0043] In this embodiment, as Figure 6 As shown, the lifting lug 13 includes a lifting lug 131 and a pair of mooring lugs 132; the upper part of the lifting lug 131 is hinged to the connecting assembly, and the lower part of the lifting lug 131 is used for lifting objects; the mooring lugs 132 are fixedly installed on both sides of the lifting lug 131 for attaching the pull wire 4.

[0044] Specifically, such as Figure 2 , Figure 3 and Figure 6 As shown, the lifting lug 131 and the mooring lug 132 of the lifting lug 13 are integrally formed. The upper part of the lifting lug 131 has a hinge hole, allowing the lifting lug 13 to be hinged to the fasteners at the bottom between the two upright plates 111 via a pin sleeve through the hinge hole in the upper part of the lifting lug 131. The lower part of the lifting lug 131 has a through hole, allowing for the descent of objects by suspending hooks and using ropes for securing them. The ends of the mooring lugs 132 on both sides away from the lifting lug 131 also have through holes, allowing the top of the pull wire 4 to be secured by passing through the through holes of the mooring lugs 132.

[0045] In this embodiment, as Figure 2 , Figure 10 and Figure 11 As shown, the midpoint between the top of the boom arm 2 and the hinge position of the connecting component, and the midpoint between the lifting lug 13 and the hinge position of the connecting component are collinear in the horizontal direction. This ensures that the combined force of the tension of the pull line 4 and the weight of the object will not exert a torque on the boom head 1.

[0046] Specifically, the lifting lug 131 is hinged to the fastener located at the lower part between the lug plates 11, and the top of the derrick arm 2 is also hinged to the hinge lug 112 via a fastener; thus, the hinge positions corresponding to the lifting lug 13 and the derrick arm 2 are both rod segments, and the axis of the rod segment at the hinge position of the lifting lug 13 intersects the midpoint of the rod segment at the hinge position of the derrick arm 2 in the extending direction. Therefore, when balancing the horizontal component of the object's weight, the horizontal component of the supporting force of the derrick arm 2 and the horizontal component of the tension of the pull line 4 intersect exactly at the midpoint of the corresponding hinge position of the lifting lug 13, ensuring that the derrick head 1 is not subjected to torque along the horizontal circumferential direction on the horizontal plane; thereby reducing the wear at the hinge positions of the derrick head 1 and the derrick arm 2, thus extending the service life of the A-frame derrick.

[0047] In this embodiment, as Figure 8 As shown, the derrick foot 3 includes a balance beam 32 and a shoe base 33. The balance beam 32 is hinged to the bottom end of the derrick arm 2, and the shoe base 33 is used for fixed installation to the ground. The shoe base 33 is hinged to the balance beam 32, and the hinge direction of the shoe base 33 and the balance beam 32 is perpendicular to the hinge direction of the balance beam 32 and the bottom end of the derrick arm 2. This ensures that the derrick arm 2 can deflect in four directions while the shoe base 33 remains in a fixed position, for the deployment and self-balancing deflection of the derrick arm 2, respectively; and that the shoe base 33 can maintain stable installation with the ground during both deployment and deflection of the derrick arm 2.

[0048] It is understandable that during the installation of A-frame derricks, the ground is not always flat due to geographical factors. Since the derrick feet 3 of traditional A-frame derricks are typically fixed to the bottom of the derrick arm 2, manual leveling is required when encountering uneven ground. Furthermore, during drop-lifting operations, the rigid connection between the derrick arm 2 and the derrick feet 3 causes the derrick arm 2 to be subjected to an overturning moment with the derrick feet 3 as the fulcrum, easily leading to overturning or bending. In this application, by multi-directionally hinged the bottom of the derrick arm 2 to the derrick feet 3, when the derrick arm 2 is subjected to an overturning moment, it can achieve self-balancing by deflecting around the derrick feet 3 in conjunction with the aforementioned lifting lugs 13. Simultaneously, due to the multi-directional hinge between the shoe base 33 and the bottom of the derrick arm 2, the installation of the shoe base 33 in any orientation will not affect the erection and deployment of the derrick arm 2.

[0049] Specifically, such as Figure 8As shown, the boot base 33 includes a mounting plate 332 and a rotating sleeve 331 fixed to the mounting plate 332; the balance beam 32 includes a third hinge plate 321 and a support shaft 322. The boot base 33 can be fixedly installed to the ground via the mounting plate 332, and the boot base 33 can be hinged to the support shaft 322 of the balance beam 32 via the rotating sleeve 331. The balance beam 32 can be hinged to the bottom end of the boom arm 2 via the third hinge plate 321.

[0050] It is understandable that the number of boot holders 33 is at least one, for example Figure 8 As shown, there is a pair of shoe seats 33. The two shoe seats 33 are respectively hinged to both sides of the support shaft 322 by rotating sleeves 331, so that the third hinge plate 321 is set in the middle of the support shaft 322 to ensure that the two shoe seats 33 provide equal support force to the derrick arm 2.

[0051] One embodiment of this application, such as Figure 2 , Figure 3 , Figure 7 and Figure 8 As shown, the derrick head 1 also includes a pair of upper hinges 12, and the derrick foot 3 also includes a lower hinge 31. The upper hinges 12 are hinged to both sides of the connecting assembly, and the lower hinge 31 is hinged to the balance beam 32. Thus, during the assembly of the A-frame derrick, the top end of the derrick arm 2 can be fixedly connected to the upper hinges 12, and the bottom end of the derrick arm 2 can be fixedly connected to the lower hinge 31, so that the top and bottom ends of the derrick arm 2 are respectively hinged to the derrick head 1 and the derrick foot 3.

[0052] Specifically, such as Figures 2 to 5 As shown, the upper hinge 12 includes a first hinge plate 121 and an upper connecting sleeve 122, with the first ends of the first hinge plate 121 and the upper connecting sleeve 122 being fixedly connected. The first hinge plate 121 can be hinged to the hinge ear 112 of the ear plate 11 by fasteners. The top end of the lever arm 2 can be inserted into the interior along the second end of the upper connecting sleeve 122 and fixedly connected to the upper connecting sleeve 122 by fasteners, so that the top end of the lever arm 2 is hinged to the ear plate 11.

[0053] At the same time, such as Figure 8 As shown, the lower hinge 31 includes a second hinge plate 312 and a lower connecting sleeve 311, with the first ends of the second hinge plate 312 and the lower connecting sleeve 311 fixedly connected. The second hinge plate 312 can be hinged to the third hinge plate 321 of the balance beam 32 by fasteners. The bottom end of the derrick arm 2 can be inserted into the lower connecting sleeve 311 along the second end and fixedly connected to the lower connecting sleeve 311 by fasteners, so that the bottom end of the derrick arm 2 is hinged to the balance beam 32.

[0054] It should be noted that during the drop hoisting process, the length of the object is not always the same each time. Therefore, when hoisting objects of different lengths, it may be necessary to adjust the length of the boom arm 2.

[0055] To facilitate the adjustment of the length of the boom arm 2, such as Figure 7 As shown, the boom arm 2 includes at least one boom tube 21, and adjacent boom tubes 21 can be detachably and fixedly connected by boom sections 22.

[0056] Understandably, when hoisting shorter objects, the boom arm 2 can be lifted using a single boom tube 21. However, when hoisting longer objects, the length of a single boom arm 21 is insufficient. In this case, an appropriate number of boom tubes 21 can be selected based on the length of the object. The ends of two adjacent boom tubes 21 can be connected by boom sections 22. After the connection is completed, the boom sections 22 and boom segments 21 are fixed with multiple fasteners, so that multiple boom tubes 21 are connected into a rigid whole.

[0057] To facilitate understanding of the self-balancing process of the A-frame derrick in this application, a more detailed explanation will be provided below, combining force analysis and relevant parameters.

[0058] (1) As Figure 9 As shown, the A-frame derrick of this application is erected on the ground, and after erection, a rope to which the object is attached is suspended by a hook. At this time, as... Figure 10 As shown, the tension F of the two pull wires 4 a and F b By decomposing the forces, we can obtain the vertical component F. a1 and F b1 Horizontal component F a2 and F b2 Among them, F a1 and F a2 Equal and opposite forces can cancel each other out; similarly, the horizontal components of the supporting forces of the two boom arms 2 are also equal and opposite, canceling each other out. Meanwhile, the two vertical components F of the two guy wires 4... b1 and F b2 Since the forces are equal in magnitude and direction, their resultant force is exactly equal in magnitude and opposite in direction to the resultant force of the vertical components of the supporting forces of the two boom arms 2, thus canceling each other out. That is, at this point, the boom arms 2 and the guy lines 4 are in a state of force equilibrium. We can assume the angle between the left guy line 4 and the ground is α, and the angle between the right guy line 4 and the ground is β, where α = β.

[0059] (2) The object is lifted upright by pulling it with ropes. At this time, the A-frame pole needs to bear the weight of the object. At the initial moment of the object being lifted, such as... Figure 10As shown, based on the principle of inverted hoisting, the center of gravity of the object can be shifted to the left side of the plane formed by the two boom arms 2. The weight G of the object can be decomposed into a vertical component G1 and a horizontal component G2. Among them, the direction of G2 is at an angle with the plane formed by the two boom arms 2, so that the boom arms 2 generate an overturning moment in the direction of the center of gravity of the object.

[0060] (3) Figure 11 As shown, under the action of the overturning moment, the boom arm 2 can deflect to the left of the pull line 4 via the lower hinge 31 around the balance beam 32. At this time, the eccentric gravity G of the object can be decomposed according to the triangle rule to obtain the component force G1 parallel to the plane formed by the two boom arms 2 and the component force G2 perpendicular to G1. Furthermore, during the deflection of the boom arm 2, the distance from the left pull line 4 to the hinge position of the traction lug 13 shortens, while the distance from the right pull line 4 to the hinge position of the traction lug 13 increases. Thus, the traction lug 13 deflects clockwise around the hinge position, so that the positional change of the traction lug 13 on both sides of the cable lug 132 balances the change in the distance of the pull line 4 caused by the deflection of the boom arm 2. During the deflection of the traction lug 13, the angle α between the left pull line 4 and the ground increases, while the angle β between the right pull line 4 and the ground decreases, thus increasing the component force F of the left pull line 4 parallel to the component force G2. a2 =F a cosα is less than the component force F of the right-side string 4 parallel to the component force G2. b2 =F b cosβ; and F a2 If the direction of the component force G2 of the object is the same, then F can be obtained. b cosβ=F a If cosα+G2, meaning the component force G2 of the eccentric gravity G of the object is balanced, then the two boom arms 2 can precisely balance and cancel out the component force G1 of the eccentric gravity G of the object through the resultant force of the axial support force. That is, the two boom arms 2 are only subjected to axial compressive force during the process of erecting the object.

[0061] The basic principles, main features, and advantages of this application have been described above. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely the principles of this application. Various changes and modifications can be made to this application without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection claimed by this application is defined by the appended claims and their equivalents.

Claims

1. A self-balancing A-frame boom, comprising a boom head, a pair of boom arms, a pair of guy lines, and a pair of boom legs, characterized in that: The boom head includes a hinged lifting lug for lifting objects and connecting the guy wire; the top end of the boom arm is hinged to the boom head, and the bottom end of the boom arm is hinged to the boom foot; when performing a drop-lifting operation, the boom arm is adapted to drive the lifting lug to deflect around the hinged position of the boom foot, thereby balancing the overturning force generated by the weight of the lifted object through the tension of the guy wire; The derrick head includes a connecting assembly and a lifting lug. Two derrick arms are respectively hinged to both sides of the connecting assembly, and the lifting lug is hinged to the middle of the connecting assembly. The rotation plane of the lifting lug is perpendicular to the rotation plane of the derrick arm around the connecting assembly. The hinge rotation plane of the derrick arm around the derrick foot is parallel to the hinge rotation plane of the lifting lug. The midpoint of the hinge position between the top of the derrick arm and the connecting assembly, and the midpoint of the hinge position between the lifting lug and the connecting assembly are collinear in the horizontal direction. The lifting lug includes a weight lug and a pair of mooring lugs; the upper part of the weight lug is hinged to the connecting assembly, and the lower part of the weight lug is used for lifting objects; the mooring lugs are fixedly disposed on both sides of the weight lug for attaching the pull wire. The derrick foot includes a balance beam and a boot seat; the balance beam is hinged to the bottom end of the derrick arm; the boot seat is suitable for fixed installation on the ground, the boot seat is hinged to the balance beam, and the hinge direction of the boot seat and the balance beam is perpendicular to the hinge direction of the balance beam and the bottom end of the derrick arm.

2. The self-balancing A-frame derrick as described in claim 1, characterized in that: The connecting assembly includes a pair of lugs, which are detachably connected by a plurality of fasteners. The lifting lug is hinged between the lugs by fasteners. The derrick arm is correspondingly hinged to the side of the lugs.

3. The self-balancing A-frame derrick as described in claim 2, characterized in that: The ear plate includes a vertical plate and a hinge ear; the two ear plates are detachably connected by the vertical plate; the hinge ear is fixed to the opposite side of the vertical plate, and the top of the lever arm is hinged to the hinge ear.

4. The self-balancing A-frame derrick as described in claim 1, characterized in that: The boot base includes a mounting plate and a rotating sleeve fixed to the mounting plate; the balance beam includes a third hinge plate and a support shaft; the boot base is fixedly installed to the ground via the mounting plate, the boot base is hinged to the support shaft via the rotating sleeve, and the balance beam is hinged to the bottom end of the boom arm via the third hinge plate.

5. The self-balancing A-frame derrick as described in claim 1, characterized in that: The derrick head also includes a pair of upper hinges, and the derrick foot also includes a lower hinge; the upper hinges are respectively hinged to both sides of the connecting assembly, and the lower hinges are hinged to the balance beam; the top end of the derrick arm is fixedly connected to the upper hinges, and the bottom end of the derrick arm is fixedly connected to the lower hinges.

6. The self-balancing A-frame derrick as described in claim 1, characterized in that: The boom arm includes at least one boom tube, and adjacent boom tubes are detachably and fixedly connected by boom sections.

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