CN116730225A - Anti-backward tilting device for arm support, arm support system and crane - Google Patents

Abstract

The application discloses a backward tilting prevention device for an arm support, an arm support system and a crane, and relates to the field of crane hoisting. The arm support anti-backward tilting device comprises a sleeve, a core tube and a limiting assembly. The sleeve comprises mutually communicated sliding holes and positioning holes; the locating hole penetrates through the wall body of the sleeve. One end of the core tube can be slidably inserted into the sliding hole of the reinforcing tube. The limiting component is rotatably arranged on the outer wall of the reinforcing pipe; in the process of changing the included angle of the sleeve relative to the ground, the included angle of the limiting assembly relative to the ground is unchanged, so that the positioning hole of the sleeve automatically rotates to a position clamped by the limiting assembly. According to the technical scheme, the arm support anti-backward tilting device has different working performances by setting two different states, so that requirements of the arm support on the arm connection and the working under the two different states are met. And effectively reduce the degree of difficulty of preventing the backward tilting, simple to operate, strong adaptability, reliability are high.

Description

Anti-backward tilting device for arm support, arm support system and crane

Technical Field

The application relates to the field of crane hoisting, in particular to a backward tilting prevention device for an arm support, an arm support system and a crane.

Background

The common backward tilting prevention device of the crane comprises a hydraulic (pneumatic) cylinder type, a heavy hammer type and a sleeve type. The hydraulic (pneumatic) cylinder type has better effect but high price, high manufacturing cost and sometimes leakage problem, so that heavy hammer type backward tilting prevention and sleeve type backward tilting prevention are mostly adopted in small tonnage.

The existing heavy hammer type anti-backward tilting device has the problem that high-altitude groove entering (or rail entering) is difficult due to the influence of machining precision and assembly errors of the two front and rear connected arm frames. In order to ensure that the anti-backward tilting smoothly enters the groove (or the rail), the prior art reduces deviation by improving the machining precision of the structural part, but the manufacturing cost is increased.

The sleeve type backward tilting prevention device has the problem that the negative angle exists between the auxiliary arm and the main arm in the process of connecting the auxiliary arm, so that the backward tilting prevention device of the sleeve type can not limit the backward tilting angle of the arm support within a reasonable range.

The inventors found that at least the following problems exist in the prior art: in the prior art, the problem of overlarge backward turning angle of the arm support is needed to be reliably solved.

Disclosure of Invention

The application provides a backward tilting prevention device for an arm support, an arm support system and a crane, which are used for reliably preventing the arm support from backward tilting.

The embodiment of the application provides a backward tilting prevention device for an arm support, which comprises the following components:

the sleeve comprises mutually communicated sliding holes and positioning holes; the positioning hole penetrates through the wall body of the sleeve;

one end of the core tube can be slidably inserted into the sliding hole of the reinforcing tube; and

the limiting component is rotatably arranged on the outer wall of the reinforcing pipe; and in the process of changing the included angle of the sleeve relative to the ground, the included angle of the limiting assembly relative to the ground is unchanged, so that the positioning hole of the sleeve automatically rotates to a position clamped by the limiting assembly.

In some embodiments, the spacing assembly comprises:

the mounting part is rotatably connected with the outer wall of the sleeve;

the limiting hook is rotatably connected with the mounting part; and

the heavy hammer is integrated with the limit hook or fixedly connected with the limit hook; the weight of the heavy hammer is matched with the weight of the limiting hook, so that the limiting hook is kept at a set position in the boom amplitude changing process.

In some embodiments, the spacing assembly further comprises:

the limiting plate is fixed in the groove of the limiting hook, and is propped against the outer wall of the sleeve when the positioning hole of the sleeve automatically rotates to a position clamped by the limiting assembly, so that the limiting hook is prevented from continuously rotating relative to the sleeve.

In some embodiments, the boom anti-recline device further comprises:

the wedge-shaped block is fixed at one end of the core tube extending into the sleeve; and when the positioning hole of the sleeve automatically rotates to a position clamped by the limiting assembly, the limiting hook hooks the wedge block.

In some embodiments, the boom anti-recline device further comprises:

a reinforcing tube fixed to an outer wall of the sleeve; the reinforcing pipe is provided with an opening; the opening is communicated with the positioning hole.

In some embodiments, a plurality of hinged mounting points are fixed to the outer wall of the sleeve, and the limiting assembly is alternatively mounted to one of the hinged mounting points.

In some embodiments, when the arm support is in the arm-receiving state, the limiting component is far away from the positioning hole of the sleeve, the sleeve and the core tube slide relatively and freely, and the length of the arm support anti-backward tilting device is a first length; when the arm support is in a working state, the limiting component is inserted into the positioning hole of the sleeve, and the length of the arm support backward tilting prevention device is a second length; wherein the first length is less than the second length.

The embodiment of the application also provides a boom system, which comprises:

a first arm support;

a second arm support; and

according to the arm support backward tilting prevention device provided by any one of the technical schemes, the other end of the sleeve pipe, which is far away from the core pipe, is rotatably connected with the first arm support, and the other end of the core pipe, which is far away from the sleeve pipe, is rotatably connected with the second arm support.

In some embodiments, the stop assembly is clamped to the sleeve when the first arm is at a 10 ° angle relative to the second arm.

In some embodiments, the stop assembly is clamped to the sleeve when the first arm is rotated 30 ° relative to the second arm.

The embodiment of the application also provides a crane, which comprises the boom system provided by any technical scheme of the application.

The arm support backward tilting prevention device provided by the technical scheme comprises a sleeve, a core tube and a limiting assembly. The sleeve and core tube may be free to slide relative to each other when the stop assembly is not inserted into the locating hole of the sleeve. After the spacing assembly is inserted into the locating hole of the sleeve, the sliding range of the sleeve and the core tube is limited. According to the technical scheme, the arm support anti-backward tilting device has different working performances by arranging two different states (the limiting assembly is inserted into the positioning hole and the limiting assembly is not inserted into the positioning hole), so that the requirements of the arm support under two different states of arm connection and work are met. And the sleeve and the core pipe can not be separated from each other all the time, the difficulty of backward tilting prevention is effectively reduced, the core pipe and the sleeve are not required to be butted in space, and the core pipe or the sleeve is not required to be inserted into a certain guide rail chute, so that the installation is convenient, the adaptability is strong, and the reliability is high.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application and do not constitute a limitation on the application. In the drawings:

fig. 1 is a schematic structural diagram of a limiting assembly of an arm support anti-backward tilting device far away from a positioning hole of a sleeve according to an embodiment of the present application.

Fig. 2 is a schematic structural diagram of a limiting assembly of a cantilever crane anti-backward tilting device according to an embodiment of the present application clamped into a positioning hole of a sleeve.

Fig. 3 is a schematic structural diagram of a limiting component of the arm support anti-backward tilting device provided by the embodiment of the application clamped into a positioning hole of a sleeve and propped against an end part of a core tube.

Fig. 4 is a schematic partial structural view of a sleeve and a reinforcing pipe of the arm support anti-backward tilting device according to an embodiment of the present application.

Fig. 5 is a schematic diagram illustrating an installation state of an anti-recline device for a boom according to an embodiment of the present application.

Fig. 6 is a schematic structural diagram of an arm support anti-backward tilting device according to an embodiment of the present application.

Fig. 7 is an enlarged schematic view at a of fig. 8.

Fig. 8 is a schematic structural diagram of a limiting hook of the arm support anti-backward tilting device entering a positioning hole of a sleeve according to an embodiment of the present application.

Fig. 9 is an enlarged schematic view at B of fig. 8.

Fig. 10 is a schematic structural diagram of the arm support anti-recline device according to the embodiment of the present application when the arm support anti-recline device is fully functional.

Fig. 11 is an enlarged schematic view at C of fig. 10.

Reference numerals:

1. a sleeve; 2. a core tube; 3. a limit component; 4. wedge blocks; 5. a reinforcing tube; 6. a hinged mounting point; 7. a first arm support; 8. a second arm support;

11. a slip hole; 12. positioning holes;

31. a mounting part; 32. a limit hook; 33. a heavy hammer; 34. a limiting plate; 321. a groove.

Detailed Description

The technical scheme provided by the application is described in more detail below with reference to fig. 1 to 11.

The crane is used for lifting heavy objects and comprises a plurality of components such as a first arm support 7, a second arm support 8 and the like. Due to the special construction of the crane itself, there may be a backward tilting of the second boom 8 relative to the first boom 7 during use. If the backward tilting angle is too large, risks and hidden danger are brought to the crane. The inventor carefully researches the phenomenon and the mechanism of the backward tilting of the second arm support 8 relative to the first arm support 7 in the prior art, and innovatively proposes to pertinently limit the backward tilting amplitude of the second arm support 8 according to the motion track of the second arm support 8 in the backward tilting process.

The embodiment of the application provides an arm support backward tilting prevention device which comprises a sleeve 1, a core tube 2 and a limiting assembly 3. The sleeve 1 comprises mutually communicated sliding holes 11 and positioning holes 12; the positioning hole 12 penetrates the wall of the sleeve 1. One end of the core tube 2 is slidably inserted into the slide hole 11 of the reinforcing tube 5. The spacing assembly 3 is rotatably mounted to the outer wall of the stiffening tube 5. Wherein, in the process that the sleeve 1 changes the included angle relative to the ground, the limiting component 3 is configured to be unchanged relative to the ground, so that the positioning hole 12 of the sleeve 1 automatically rotates to a position clamped by the limiting component 3.

When the telescopic pipe is used, one end of the sleeve pipe 1, which is far away from the core pipe 2, is rotatably connected with the first arm support 7, and one end of the core pipe 2, which is far away from the sleeve pipe 1, is rotatably connected with the second arm support 8. The angle alpha of the core tube 2 and the sleeve 1 relative to the horizontal plane can be changed along with the change of the included angles of the first arm support 7 and the second arm support 8. However, the included angle β of the limiting assembly 3 relative to the horizontal plane is always unchanged, so that the included angle between the center line of the sleeve 1 and the limiting assembly 3 can be changed, and when the sleeve 1 reaches a certain position relative to the limiting assembly 3, the positioning hole 12 of the sleeve 1 can be clamped by the limiting assembly 3, so that the sleeve 1 can not rotate relative to the limiting assembly 3 any more.

The included angle between the first arm support 7 and the second arm support 8 which are connected during arm connection is a negative angle, namely the second arm support 8 rises a certain angle relative to the first arm support 7, at the moment, the length of the backward tilting prevention device is required to be shortest, namely the part of the core tube 2 inserted into the sleeve 1 is longest, and the length of the whole arm support backward tilting prevention device is shortest. The limiting component 3 is rotatably connected with the sleeve 1, and the included angle of the limiting component 3 relative to the ground is unchanged all the time under the action of self gravity of the limiting component 3. When the arm is connected, the limiting component 3 is completely separated from the positioning hole 12 of the sleeve 1.

Along with the increase of the boom lifting angle, the included angle between the first boom 7 and the second boom 8 starts to increase, the sleeve 1 and the core pipe 2 slide relatively, the core pipe 2 is gradually pulled out of the sleeve 1, and the sleeve 2 and the core pipe are far away from each other until the first boom 7 and the second boom 8 rotate to a specified included angle, and at the moment, the boom backward tilting prevention device is located at the longest distance designed under the working condition. Before the limiting component 3 is clamped into the positioning hole 12 of the sleeve 1 in the arm lifting process, the center of gravity of the limiting component 3 is always located at the same set position with the hinge point under the action of self gravity, so that the limiting component 3 is always kept motionless in the arm lifting process. The sleeve 1 and the core tube 2 are respectively hinged on the first arm support 7 and the second arm support 8, so that the angle of the sleeve 1 and the core tube relative to the ground changes along with the arm lifting process in the continuous extension process, the limiting assembly 3 and the sleeve 1 relatively rotate, and the final effect is that the limiting assembly 3 enters the sleeve 1 through the positioning hole 12 of the sleeve 1 so as to lock the relative positions of the sleeve 1 and the limiting assembly 3.

When the arm support tilts backward, the arm support is prevented from entering a working state, as shown in fig. 3, the arm support tilts backward to drive the core tube 2 to move in the sleeve 1, but due to the existence of the limiting component 3, the travel of the core tube 2 in the arm support tilting backward process is limited, the first arm support 7 and the second arm support 8 are further limited to tilt backward, and the second arm support 8 cannot tilt backward at a larger angle relative to the first arm support 7 by limiting the locking positions of the limiting component 3 and the positioning hole 12.

Aiming at the working conditions of different arm support included angles, a plurality of hinging installation points 6 are arranged in the embodiment of the application, and as shown in fig. 1 to 3, the limiting component 3 is alternatively arranged at one hinging installation point 6. The position of the limiting component 3 can be adjusted according to different angles of the first arm support 7 and the second arm support 8, so that the working condition that one arm support anti-backward tilting device corresponds to various arm support connecting angles is realized, the problem that the backward tilting angle of the second arm support 8 is overlarge under the condition that the arm support anti-backward tilting device completely abuts against a dead state when different installation angles are solved, the limiting component can be limited in an ideal range, and the designability is realized. In addition, according to the technical scheme, only one set of arm support backward tilting prevention device is needed, the cost is increased slightly, the backward tilting prevention effect is obviously improved, and the product safety and reliability are extremely high; compared with the prior cylinder type, heavy hammer type and compression spring type backward tilting prevention device, the backward tilting prevention device for the arm support provided by the embodiment of the application has the advantages of simple structural form, low manufacturing cost, convenience in installation, strong adaptability and high reliability (the heavy hammer type structure in the prior art is radically eradicated that the heavy hammer type structure is difficult to enter a rail and the risk of unhooking possibly exists), and the disassembly and assembly efficiency is obviously improved. Because the number of the parts is small, the device has the advantages of low failure rate, easy disassembly and assembly, easy inspection and low later maintenance cost.

In some embodiments, the boom mounting angle delta is exemplified as 10 degrees and 30 degrees, but multiple groups or different angles can be set in actual engineering. The first position shown in fig. 2 is the position of the limiting component 3 when the boom installation angle is 10 degrees, and the second position is the position of the limiting component 3 when the boom included angle is 30 degrees. Wherein, spacing subassembly 3 is through round pin axle and sleeve pipe 1 detachably articulated, easy dismouting.

In some embodiments, the spacing assembly 3 includes a mounting portion 31, a spacing hook 32, and a weight 33. The mounting part 31 is rotatably connected with the outer wall of the sleeve 1; the stopper hook 32 is rotatably connected to the mounting portion 31. The weight 33 and the limit hook 32 are integrated or fixedly connected; wherein the weight of the weight 33 matches the weight of the limit hook 32, so that the limit hook 32 is kept at a set position during boom luffing.

In some embodiments, the limiting assembly 3 further includes a limiting plate 34, where the limiting plate 34 is fixed in the groove 321 of the limiting hook 32, so as to abut against the outer wall of the sleeve 1 when the positioning hole 12 of the sleeve 1 rotates to a position clamped by the limiting assembly 3 automatically, so as to prevent the limiting hook 32 from rotating continuously relative to the sleeve 1.

The mounting portion 31 is provided with a pin hole through which the pin shaft passes to rotatably connect the mounting portion 31 and the outer wall of the sleeve 1. After rotatable connection, the whole limiting component 3 can freely and automatically rotate around the pin shaft, namely, the rotation of the sleeve 1 can not drive the limiting component 3 to synchronously rotate. The limiting component 3 is always kept in the balance state of the limiting hook 32 and the heavy hammer 33 under the action of self gravity.

Referring to fig. 6 and 7, when the crawler crane is connected to the arm, the included angle between the first arm support 7 and the second arm support 8 is 180 ° and is horizontal, and further the included angle between the two is a negative angle, that is, the second arm support 8 is raised by a certain angle relative to the first arm support 7. This maximizes the travel of the core tube 2 within the sleeve 1 during arm attachment, and maximizes the length of insertion of the core tube 2 into the sleeve 1, i.e., minimizes the length of the arm rest anti-recline device. At this time, the limiting assembly 3 makes the limiting hook 32 far away from the positioning hole 12 of the sleeve 1 due to the gravity center position, and the heavy hammer 33 is close to the sleeve 1.

In the arm connecting process, as each part of the limiting component 3 is completely positioned on the outer side of the sleeve 1, the core pipe 2 can slide along the sleeve 1 in an unobstructed manner, so that the arm support anti-backward tilting device is retracted to the shortest length required in the arm connecting state, and the mounting problem of the arm support anti-backward tilting device caused by the fact that negative angles possibly exist between the first arm support 7 and the second arm support 8 when the auxiliary arm of the crane is connected with the arm is effectively solved.

Referring to fig. 8 and 9, in the subsequent boom lifting process, as the first boom 7 is lifted continuously, the angle between the first boom 7 and the second boom 8 is increased continuously. The sleeve 1 is hinged with the first arm support 7, and the core tube 2 is hinged with the second arm support 8, so that the core tube 2 continuously slides out of the sleeve 1 along with the continuous increase of the angle between the first arm support 7 and the second arm support 8, namely the length of the arm support backward tilting prevention device is continuously increased. The second arm support 8 then leaves the ground, the angle between the first arm support 7 and the second arm support 8 is fixed, and thus the length between the sleeve 1 and the core tube 2 is fixed. However, in the above process, as the length and the position of the sleeve 1 are continuously changed, the relative angle between the limiting component 3 hinged with the sleeve 1 and the sleeve 1 is also changed along with the change of the inclination angle of the sleeve 1, that is, the included angle between the limiting component 3 and the sleeve 1 is changed in the process of changing the position and the length of the sleeve 1. In this process, the stopper hook 32 starts to enter the inside of the sleeve 1 through the positioning hole 12 of the sleeve 1, and finally stops moving under the action of a stopper plate 34 described later, but at this time the stopper hook 32 has completely entered the inside of the sleeve 1, as shown in fig. 9.

Since the angle between the first arm support 7 and the second arm support 8 is not changed after the second arm support 8 leaves the ground, the length between the sleeve 1 and the core tube 2 is fixed in the subsequent arm lifting process until the arm support is lifted to the working angle.

Referring to fig. 10 and 11, in the subsequent working process, if sudden emergency such as strong wind and sudden unloading is suddenly encountered, the second arm support 8 has a tendency or possibility of backward tilting, and when the second arm support 8 is backward tilted, the angle between the first arm support 7 and the second arm support 8 becomes smaller, so that the core tube 2 moves in the sleeve 1 under the action of the movement of the second arm support 8, and along with the continuous backward tilting of the second arm support 8, the backward tilting prevention length starts to be continuously reduced until the end part of the core tube 2 is limited by the limiting hook 32, the core tube 2 cannot continue to move relative to the sleeve 1, and further the backward tilting behavior of the second arm support 8 is limited, thereby realizing the backward tilting prevention function of the crawler crane arm support, as shown in fig. 11.

As can be seen from fig. 6 and 7, when the anti-backward tilting length is the shortest, the portion of the core tube 2 inserted into the sleeve 1 is the longest, the core tube 2 has the greatest displacement inside the sleeve 1, and at this time, the angle between the first arm support 7 and the second arm support 8 is the smallest. As can be seen from fig. 10 and 11, when the arm support anti-recline device is fully functional, the core tube 2 does not reach the maximum travel inside the sleeve 1 due to the limiting effect of the limiting hook 32, i.e. the length of the arm support anti-recline device for preventing recline is greater than the length of the arm support anti-recline device for receiving arm when the arm support anti-recline device is fully functional, which can prevent the first arm support 7 and the second arm support 8 from reaching the minimum angle, thereby realizing the arm support anti-recline function. The anti-backward tilting device of the arm support has different strokes under different working states, so that the sleeve 1 and the core tube 2 can be directly connected with the first arm support 7 and the second arm support 8, the difficulty in backward tilting of the crane into a rail and the risk of derailment are radically eliminated, and meanwhile, the problem that the backward tilting angle of the second arm support 8 is overlarge still when the anti-backward tilting is fully effective is solved.

In some embodiments, the arm support anti-backward tilting device further comprises a wedge block 4, wherein the wedge block 4 is fixed at one end of the core tube 2 extending into the sleeve 1; wherein, when the positioning hole 12 of the sleeve 1 automatically rotates to a position clamped by the limiting component 3, the limiting hook 32 hooks the wedge block 4.

The arm support anti-backward tilting device has two lengths: the length in the arm connection state and the length in the working state. The first length in the arm-receiving state is defined by the stop hooks 32 of the stop assembly 3 being remote from the positioning holes 12 of the sleeve 1, i.e. in this state the sleeve 1 and the core tube 2 are relatively free to rotate and the core tube 2 can be fully inserted into the sleeve 1. The first length in the arm-receiving state refers to the shortest length of the arm-rest anti-backward tilting device in this state.

The second length in the working state is achieved by the stop hook 32 of the stop assembly 3 entering the positioning hole 12 of the sleeve 1. The second length in the working state refers to the shortest length of the backward tilting prevention device of the arm frame in the state.

Wherein the first length in the arm-connecting state is smaller than the second length in the working state. The length of the working state can be multiple according to the different installation angles of the arm support, and the working state is realized by setting different installation points of the limiting assembly 3.

In some embodiments, the boom anti-recline device further comprises a stiffening tube 5, the stiffening tube 5 being fixed to the outer wall of the sleeve 1, such as in particular welded. The reinforcing tube 5 is provided with an opening; the opening communicates with the positioning hole 12.

The embodiment of the application also provides a boom system, which comprises the first boom 7 and the second boom 8 provided by any technical scheme of the application and the boom backward tilting prevention device provided by any technical scheme of the application. The other end of the sleeve 1 far away from the core tube 2 is rotatably connected with the first arm support 7, and the other end of the core tube 2 far away from the sleeve 1 is rotatably connected with the second arm support 8.

In some embodiments, the stop assembly 3 is clamped to the sleeve 1 when the angle of rotation of the first arm 7 relative to the second arm 8 is 10 °.

In some embodiments, the stop assembly 3 is clamped to the sleeve 1 when the angle of rotation of the first arm 7 relative to the second arm 8 is 30 °.

According to the arm support anti-backward tilting device provided by the technical scheme, the sleeve 1 and the core tube 2 are directly hinged with the first arm support 7 and the second arm support 8, the sleeve 1 and the core tube 2 are not separated all the time, the sleeve 1 and the core tube 2 can slide relatively, the link that the arm support anti-backward tilting device slides into the track of the first arm support 7 or the track of the second arm support 8 in high air is not needed, the reliability of the arm support anti-backward tilting device is not influenced by the manufacturing and assembling precision of the first arm support 7 and the second arm support 8, the reliability of the arm support anti-backward tilting device is only dependent on the reliability of the arm support anti-backward tilting device, the reliability of the arm support anti-backward tilting device is easy to guarantee, the ground can be verified, the derailment risk does not exist, and the reliability of the arm support anti-backward tilting device is greatly improved.

The embodiment of the application also provides a crane, which comprises the boom system provided by any technical scheme of the application.

In the description of the present application, it should be understood that the terms "center," "longitudinal," "lateral," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, merely to facilitate description of the present application and simplify the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the protection of the present application.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and are not limiting; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may be modified or some technical features may be replaced with others, which may not depart from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims (11)

1. The utility model provides a cantilever crane prevents backward tilting device which characterized in that includes:

the sleeve (1) comprises mutually communicated sliding holes (11) and positioning holes (12); the positioning hole (12) penetrates through the wall body of the sleeve (1);

a core tube (2), one end of which can be slidably inserted into a sliding hole (11) of the reinforcing tube (5); and

the limiting component (3) is rotatably arranged on the outer wall of the reinforcing pipe (5); wherein, in the process that the included angle of the sleeve (1) is changed relative to the ground, the included angle of the limiting component (3) is unchanged relative to the ground, so that the positioning hole (12) of the sleeve (1) automatically rotates to a position clamped by the limiting component (3).

2. The boom anti-recline device according to claim 1, wherein the limit assembly (3) comprises:

a mounting part (31) rotatably connected with the outer wall of the sleeve (1);

a limit hook (32) rotatably connected with the mounting part (31); and

the heavy hammer (33) is integrated with the limit hook (32) or fixedly connected with the limit hook; wherein the weight of the heavy hammer (33) is matched with the weight of the limit hook (32) so that the limit hook (32) is kept at a set position in the boom amplitude variation process.

3. The boom anti-recline device according to claim 1, wherein the limit assembly (3) further comprises:

the limiting plate (34) is fixed in the groove (321) of the limiting hook (32) so as to abut against the outer wall of the sleeve (1) when the positioning hole (12) of the sleeve (1) automatically rotates to a position clamped by the limiting assembly (3), so that the limiting hook (32) is prevented from continuing to rotate relative to the sleeve (1).

4. The boom anti-roll apparatus of claim 1, further comprising:

the wedge-shaped block (4) is fixed at one end of the core tube (2) extending into the sleeve (1); when the positioning hole (12) of the sleeve (1) automatically rotates to a position clamped by the limiting assembly (3), the limiting hook (32) hooks the wedge-shaped block (4).

5. The boom anti-roll apparatus of claim 1, further comprising:

a reinforcing tube (5) fixed to the outer wall of the sleeve (1); the reinforcing tube (5) is provided with an opening; the opening communicates with the positioning hole (12).

6. The arm support anti-backward tilting device according to claim 1, wherein a plurality of hinge mounting points (6) are fixed on the outer wall of the sleeve (1), and the limiting assembly (3) is alternatively arranged on one of the hinge mounting points (6).

7. The boom anti-recline device of claim 1, wherein,

when the arm support is in an arm connection state, the limiting assembly (3) is far away from the positioning hole (12) of the sleeve (1), the sleeve (1) and the core tube (2) slide relatively and freely, and the length of the arm support backward tilting prevention device is a first length;

when the arm support is in a working state, the limiting component (3) is inserted into the positioning hole (12) of the sleeve (1), and the length of the arm support backward tilting prevention device is a second length;

wherein the first length is less than the second length.

8. A boom system, comprising:

a first arm support (7);

a second arm support (8); and

the arm support backward tilting prevention device according to any one of claims 1 to 7, wherein the other end of the sleeve (1) away from the core tube (2) is rotatably connected with the first arm support (7), and the other end of the core tube (2) away from the sleeve (1) is rotatably connected with the second arm support (8).

9. Boom system according to claim 8, characterized in that the limit assembly (3) is clamped with the sleeve (1) when the angle of rotation of the first boom (7) relative to the second boom (8) is 10 °.

10. Boom system according to claim 8, characterized in that the limit assembly (3) is clamped with the sleeve (1) when the angle of rotation of the first boom (7) with respect to the second boom (8) is 30 °.

11. Crane, characterized by comprising a boom system according to any of claims 8-10.