Crane telescopic arm limiting mechanism

Abstract

The utility model discloses a crane telescopic arm limiting mechanism which comprises a sleeve, a telescopic pipe is arranged in the sleeve in a sliding mode, a limiting device is arranged in the sleeve, the limiting device comprises a center rod, a fixing sleeve, a limiting sleeve, a sliding hole, an arc-shaped rod, a push plate, a clamping block and a clamping groove, the center rod is installed in the sleeve, and the limiting sleeve is installed in the arc-shaped rod. The fixing sleeve is installed on the center rod, the limiting sleeve is installed in the telescopic pipe, the multiple sets of sliding holes are distributed in the outer side of the limiting sleeve, the arc-shaped rods are installed in the multiple sets of sliding holes in a sliding mode, the push plate is arranged in the limiting sleeve, and the clamping blocks are installed at the bottom ends of the multiple sets of arc-shaped rods. A plurality of clamping grooves are formed in the outer wall of the fixing sleeve, guide wheels are installed at the two ends of the sleeve, and therefore the technical problems that in the background technology, a telescopic arm without a limiting device is prone to excessively stretching or contracting, and the risk of equipment damage and safety accidents is increased are solved.

Description

Technical Field

[0001] The utility model relates to the technical field of cranes, and more particularly to a telescopic arm limiting mechanism of a crane. Background Art

[0002] In existing technologies, precise control of the telescopic boom length is crucial for safety and efficiency in modern crane operations, especially in complex working environments such as high-rise building construction or operations in confined spaces. Operators need to be able to quickly and accurately adjust the telescopic boom length while ensuring it is securely locked in the desired position. However, traditional telescopic boom designs often lack effective limiter mechanisms, leading to a series of potential problems. Telescopic booms without limiters are prone to over-extension or over-contraction, increasing the risk of equipment damage and safety accidents. Operators need to rely on experience and visual judgment to control the position of the telescopic boom, which not only increases operational difficulty but can also reduce work efficiency due to human error.

[0003] In lifting operations that require precise positioning, such as the installation of precision equipment or the lifting of large components, telescopic arms without limiting devices are even more difficult to meet the requirements. Without a reliable limiting mechanism, the telescopic arm may slip slightly when bearing the load, affecting the lifting accuracy. In addition, in operations that require maintaining a fixed position for a long time, such as high-altitude maintenance or long-term support operations, traditional telescopic arms are difficult to ensure long-term stability. Operators may need to frequently check and adjust the position of the telescopic arm, which not only increases the workload but also may distract attention and ignore other important safety factors. These problems not only reduce the working efficiency of the crane, but also increase operational risks, highlighting the urgent need to develop a reliable and precise telescopic arm limiting mechanism. Utility Model Content

[0004] (1) Technical problems solved

[0005] In response to the problems existing in the prior art, the utility model provides a crane telescopic arm limiting mechanism to solve the technical problem mentioned in the background technology that the telescopic arm without a limiting device is prone to over-extension or contraction, increasing the risk of equipment damage and safety accidents.

[0006] (2) Technical solution

[0007] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a crane telescopic arm limiting mechanism, comprising a sleeve, a telescopic tube slidingly provided in the sleeve, a limiting device provided in the sleeve, the limiting device comprising a center rod, a fixed sleeve, a limiting sleeve, a sliding hole, an arc rod, a push plate, a clamping block and a clamping slot, the center rod is installed in the sleeve, the fixed sleeve is installed on the center rod, the limiting sleeve is installed in the telescopic tube, the sliding holes are provided with multiple groups distributed on the outside of the limiting sleeve, the arc rod is slidably installed in multiple groups of the sliding holes, the push plate is provided in the limiting sleeve, the clamping block is installed at the bottom end of multiple groups of the arc rods, the clamping slot is provided with multiple groups distributed on the outer wall of the fixed sleeve, guide wheels are installed at both ends of the sleeve, guide cables are provided on multiple groups of the guide wheels, and multiple groups of the guide cables are connected to the side walls of the telescopic tube.

[0008] The utility model is further configured as follows: the outer wall of the limit sleeve is provided with a locking device, and the locking device includes a rotating sleeve, an inner gear ring, a support block, a screw, a gear, a locking sleeve, a locking block and a locking hole, the rotating sleeve is rotatably mounted on the bottom end of the limit sleeve, the inner gear ring is mounted on the top surface of the rotating sleeve, the support block is provided with multiple groups mounted on the outer wall of the limit sleeve, the screw is provided with multiple groups and respectively rotatably mounted on multiple groups of support blocks, the gear is mounted on the bottom ends of multiple groups of screws and meshes with the inner gear ring, the locking sleeve slides on the outer wall of the limit sleeve and is threadedly connected with multiple groups of screws, the locking block is provided with multiple groups and mounted on the top surface of the locking sleeve, and the locking hole is provided on multiple groups of arc rods. This design not only enhances the limiting effect, but also provides additional safety when it is necessary to maintain a fixed position for a long time. The adjustability of the locking device enables the operator to flexibly control the locking strength according to actual needs.

[0009] The utility model is further configured such that the inner wall of the limiting sleeve is provided with a positioning strip, and the outer wall of the fixing sleeve is provided with a strip groove. The positioning strips and the strip grooves are provided in multiple groups and are all slidably connected. This design ensures the relative position stability between the limiting sleeve and the fixing sleeve, improves the stability of the entire limiting mechanism, and ensures that the arc rod and the card block can be accurately aligned with the card slot, thereby enhancing the reliability of the limiting effect.

[0010] The utility model is further configured such that sliding grooves are provided in multiple groups of sliding holes, sliding strips are provided on the outer walls of multiple groups of arc-shaped rods, and multiple groups of sliding strips are respectively slidably connected to the multiple groups of sliding grooves. This design provides precise guidance of the arc-shaped rods, improves the accuracy of the limiting operation, reduces the wear between the arc-shaped rods and the sliding holes, and extends the service life of the entire mechanism.

[0011] The utility model is further configured such that push blocks are installed at the top ends of the multiple groups of arc-shaped rods, and resistance springs are connected between the multiple groups of push blocks and the inner walls of the limit sleeves. This design provides the arc-shaped rods with an automatic reset function. This automatic reset mechanism not only simplifies the operation, but also improves the response speed and reliability of the limit mechanism.

[0012] The utility model is further configured such that a compression spring is connected between the push plate and the inner top surface of the limit sleeve, and the compression spring is provided in multiple groups. The setting of the compression spring ensures that the push plate maintains continuous contact with the inner wall of the telescopic tube. The use of multiple groups of compression springs disperses the pressure, avoids local stress concentration, and also provides a more uniform thrust, ensuring that the push plate can smoothly and effectively activate all arc rods.

[0013] The utility model is further configured such that a connecting plate is installed inside the telescopic tube, and the connecting plate is slidably connected to the center rod. The design of the connecting plate provides a stable connection between the telescopic tube and the center rod. The connecting plate can also serve as a support point for the internal structure of the telescopic tube, thereby improving the rigidity and load-bearing capacity of the entire telescopic arm.

[0014] The present invention is further configured as follows: the rotating sleeve is provided with a positioning device, the positioning device includes a positioning groove, a positioning block and a push spring, the positioning grooves are provided with multiple groups distributed on the outer wall of the limit sleeve, the positioning blocks are provided with multiple groups and are all slidably installed on the rotating sleeve, the push springs are provided with multiple groups and the two ends are respectively connected to the outer wall of the rotating sleeve and the top ends of the multiple groups of positioning blocks. This design enables the rotating sleeve to stop at a preset position and remain stable during the rotation process, which not only improves the accuracy of the locking operation, but also reduces the workload of the operator.

[0015] (3) Beneficial effects

[0016] Compared with the prior art, the present invention provides a crane telescopic arm limiting mechanism, which has the following beneficial effects:

[0017] 1. Beneficial effects of the limit device: The device achieves precise limitation of the position of the telescopic tube through the ingenious cooperation of the center rod, fixed sleeve, limit sleeve, sliding hole, curved rod, push plate, block and slot. When the telescopic tube reaches the preset position, the limit sleeve moves accordingly, and the push plate pushes the curved rod to move outward through the sliding hole, so that the block is inserted into the slot on the outer wall of the fixed sleeve, thereby effectively preventing the telescopic tube from continuing to move. This design can not only accurately control the length of the telescopic arm, but also prevent accidental sliding, greatly improving the safety of crane operation. The design of multiple sets of curved rods and blocks further enhances the reliability of the limit, ensuring that the limit function can be maintained even if one component fails. The sliding groove in the sliding hole cooperates with the sliding strip on the outer wall of the curved rod to ensure the smooth and accurate movement of the curved rod. The spring design between the push block and the inner wall of the limit sleeve provides appropriate resistance to prevent the curved rod from moving too easily and causing misoperation, while also facilitating the release of the limit when needed.

[0018] 2. Beneficial effects of the locking device: The device consists of a rotating sleeve, an inner gear ring, a support block, a screw, a gear, a locking sleeve, a locking block and a locking hole, providing a reliable secondary locking mechanism. By rotating the rotating sleeve, the inner gear ring drives the gear to rotate, and then drives the screw to rotate, so that the locking sleeve moves up and down on the outer wall of the limit sleeve. When the locking sleeve moves up, the locking block enters the locking hole on the arc rod to further fix the position of the arc rod. This design not only enhances the limiting effect, but also provides additional safety when it needs to maintain a fixed position for a long time. The adjustability of the locking device enables the operator to flexibly control the locking strength according to actual needs. The setting of the support block ensures the stability of the screw to prevent it from deflecting or loosening during use. The design of multiple sets of screws and locking blocks provides evenly distributed locking force, avoids local stress concentration, and extends the service life of the device.

[0019] 3. Beneficial effects of the positioning device: The device includes a positioning groove, a positioning block and a push spring, which provides precise position control for the locking device. The positioning grooves are distributed on the outer wall of the limit sleeve, and the positioning block is slidably installed on the rotating sleeve. The two are connected by a push spring. This design enables the rotating sleeve to stop at a preset position and remain stable during rotation. The positioning block automatically finds and enters the positioning groove under the action of the push spring, thereby realizing precise control of the position of the rotating sleeve. This not only improves the accuracy of the locking operation, but also reduces the workload of the operator. The setting of multiple groups of positioning blocks and positioning grooves increases the positioning points, allowing the operator to select a suitable locking position according to different work requirements. The use of push springs not only ensures the reliability of positioning, but also allows position adjustment by overcoming the push spring pressure with appropriate force when needed. This flexibility enables the device to adapt to various working conditions and improves the practicality and efficiency of the entire limiting mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1This is a schematic diagram of the overall structure of a crane telescopic arm limiting mechanism in the utility model;

[0021] Figure 2 This is a schematic cross-sectional view of the sleeve and the telescopic tube in the utility model;

[0022] Figure 3 This is a schematic cross-sectional view of the limiting mechanism of the present invention;

[0023] Figure 4 This is a schematic cross-sectional view of the locking device in the present invention;

[0024] Figure 5 It is a schematic cross-sectional structural diagram of the positioning device in the present utility model.

[0025] In the figure: 1. sleeve; 2. telescopic tube; 3. center rod; 4. fixing sleeve; 5. limiting sleeve; 6. sliding hole; 7. arc rod; 8. push plate; 9. clamping block; 10. clamping slot; 11. guide wheel; 12. guide cable; 13. rotating sleeve; 14. inner gear ring; 15. support block; 16. screw; 17. gear; 18. locking sleeve; 19. locking block; 20. locking hole; 21. positioning strip; 22. strip groove; 23. sliding slot; 24. sliding strip; 25. pushing block; 26. resisting spring; 27. compression spring; 28. connecting plate; 29. ​​positioning slot; 30. positioning block; 31. pushing spring. DETAILED DESCRIPTION

[0026] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0027] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by ordinary technicians in the technical field to which this application belongs.

[0028] In the present invention, unless otherwise specified, directions such as "up" and "down" are usually relative to the directions shown in the drawings, or relative to the vertical, perpendicular or gravity direction; similarly, for ease of understanding and description, "left" and "right" are usually relative to the left and right shown in the drawings; "inside" and "outside" refer to the inside and outside relative to the outline of each component itself, but the above-mentioned direction words are not used to limit the present invention.

[0029] See also Figure 1-Figure 5A telescopic arm limiting mechanism of a crane comprises a sleeve 1, a telescopic tube 2 is slidingly provided in the sleeve 1, a limiting device is provided in the sleeve 1, the limiting device comprises a center rod 3, a fixed sleeve 4, a limiting sleeve 5, a sliding hole 6, an arc rod 7, a push plate 8, a block 9 and a slot 10, the center rod 3 is installed in the sleeve 1, the fixed sleeve 4 is installed on the center rod 3, the limiting sleeve 5 is installed in the telescopic tube 2, the sliding holes 6 are provided with multiple groups distributed on the outside of the limiting sleeve 5, the arc rod 7 is slidably installed in the multiple groups of sliding holes 6, the push plate 8 is provided in the limiting sleeve 5, the block 9 is installed at the bottom end of the multiple groups of arc rods 7, the slot 10 is provided with multiple groups distributed on the outer wall of the fixed sleeve 4, guide wheels 11 are installed at both ends of the sleeve 1, guide cables 12 are provided on the multiple groups of guide wheels 11, and the multiple groups of guide cables 12 are connected to the side walls of the telescopic tube 2.

[0030] A locking device is provided on the outer wall of the limit sleeve 5, which includes a rotating sleeve 13, an inner gear ring 14, a support block 15, a screw 16, a gear 17, a locking sleeve 18, a locking block 19 and a lock hole 20. The rotating sleeve 13 is rotatably installed at the bottom end of the limit sleeve 5, the inner gear ring 14 is installed on the top surface of the rotating sleeve 13, the support block 15 is provided with multiple groups installed on the outer wall of the limit sleeve 5, the screw 16 is provided with multiple groups and is rotatably installed on multiple groups of support blocks 15, the gear 17 is installed at the bottom end of multiple groups of screws 16 and meshes with the inner gear ring 14, the locking sleeve 18 slides on the outer wall of the limit sleeve 5 and is threadedly connected with multiple groups of screws 16, the locking block 19 is provided with multiple groups and is installed on the top surface of the locking sleeve 18, and the lock hole 20 is provided on multiple groups of arc rods 7.

[0031] A positioning strip 21 is provided on the inner wall of the limiting sleeve 5, and a strip groove 22 is provided on the outer wall of the fixing sleeve 4. There are multiple groups of positioning strips 21 and strip grooves 22, and they are all slidably connected. The sliding connection of multiple groups of positioning strips 21 and strip grooves 22 allows the limiting sleeve 5 to move axially on the fixing sleeve 4 while preventing the two from rotating relative to each other.

[0032] A sliding groove 23 is provided in each of the multiple sets of sliding holes 6, and a sliding bar 24 is provided on the outer wall of each of the multiple sets of arc rods 7. The multiple sets of sliding bars 24 are respectively slidably connected to the multiple sets of sliding grooves 23. The sliding of the sliding bars 24 in the sliding grooves 23 ensures that the arc rods 7 maintain a stable trajectory during radial movement, preventing the arc rods 7 from tilting or rotating.

[0033] Push blocks 25 are installed at the top of multiple groups of arc rods 7, and resistance springs 26 are connected between multiple groups of push blocks 25 and the inner wall of the limit sleeve 5. The resistance springs 26 keep the arc rods 7 in the retracted position under normal conditions. When limiting is required, the push plate 8 presses down the push blocks 25, overcomes the force of the resistance springs 26 and moves the arc rods 7 outward. When the limit is released, the elastic force of the resistance springs 26 can automatically restore the arc rods 7 to their initial position.

[0034] A compression spring 27 is connected between the push plate 8 and the inner top surface of the limit sleeve 5. Multiple groups of compression springs 27 are provided. This elastic connection enables the push plate 8 to adapt to slight deformation or unevenness of the inner wall of the telescopic tube 2, ensuring the sensitivity and reliability of the limit trigger.

[0035] A connecting disc 28 is installed in the telescopic tube 2, and the connecting disc 28 is slidably connected to the center rod 3. The sliding connection allows the telescopic tube 2 to move axially relative to the center rod 3 while maintaining a stable radial position. This design not only ensures the movement accuracy of the telescopic tube 2, but also reduces friction and wear during the telescopic process.

[0036] In this embodiment, when the crane needs to adjust the length of the telescopic arm, the telescopic tube 2 slides in the sleeve 1, and the guide wheel 11 and the guide cable 12 ensure the smooth movement of the telescopic tube 2. When the telescopic tube 2 reaches the preset position, the limit sleeve 5 moves to the preset position. At this time, the fixed sleeve 4 provided on the center rod 3 is inserted into the limit sleeve 5, and the top of the fixed sleeve 4 abuts the push plate 8. The push plate 8 pushes the multiple groups of push blocks 25. The push blocks 25 drive the multiple groups of arc rods 7 to slide outward along the multiple groups of sliding holes 6. The block 9 at the bottom end of the arc rod 7 is inserted into the card groove 10 on the outer wall of the fixed sleeve 4, thereby limiting the extension. Further movement of the telescopic tube 2, when it is necessary to lock the position of the telescopic tube 2 for a long time, the operator rotates the rotating sleeve 13, and the internal gear ring 14 on the rotating sleeve 13 drives the gear 17 engaged therewith to rotate, and the gear 17 drives the screw 16 to rotate. Since the screw 16 is threadedly connected to the locking sleeve 18, the locking sleeve 18 will move up and down along the outer wall of the limiting sleeve 5. When the locking sleeve 18 moves up, the locking block 19 will enter the locking hole 20 on the arc rod 7, further fixing the position of the arc rod 7 and enhancing the limiting effect. Conversely, when the locking sleeve 18 moves down, the locking block 19 disengages from the locking hole 20, releasing the locked state.

[0037] See also Figure 5 As an implementation method of the positioning device: a positioning device is provided on the rotating sleeve 13, and the positioning device includes a positioning groove 29, a positioning block 30 and a push spring 31. There are multiple groups of positioning grooves 29 distributed on the outer wall of the limit sleeve 5, and there are multiple groups of positioning blocks 30 that are all slidably installed on the rotating sleeve 13. There are multiple groups of push springs 31 and their two ends are respectively connected to the outer wall of the rotating sleeve 13 and the top of the multiple groups of positioning blocks 30.

[0038] More specifically, when the rotating sleeve 13 rotates, the positioning block 30 will try to enter the positioning groove 29 on the outer wall of the limiting sleeve 5 under the action of the push spring 31. When the positioning block 30 enters the positioning groove 29, the position of the rotating sleeve 13 is fixed, thereby achieving precise control of the locking device. If the position needs to be adjusted, it is only necessary to apply sufficient force to overcome the pressure of the push spring 31 to disengage the positioning block 30 from the positioning groove 29, and then the position of the rotating sleeve 13 can be readjusted.

[0039] In summary, when the entire device is in use or running: when the crane needs to adjust the length of the telescopic arm, the telescopic tube 2 slides in the sleeve 1, and the guide wheel 11 and the guide cable 12 ensure the smooth movement of the telescopic tube 2. When the telescopic tube 2 reaches the preset position, the limit sleeve 5 moves to the preset position accordingly. At this time, the fixed sleeve 4 provided on the center rod 3 is inserted into the limit sleeve 5, and the top of the fixed sleeve 4 abuts the push plate 8. The push plate 8 will push the multiple groups of push blocks 25. The push blocks 25 drive the multiple groups of arc rods 7 to slide outward along the multiple groups of sliding holes 6. The block 9 at the bottom end of the arc rod 7 will be inserted into the slot 10 on the outer wall of the fixed sleeve 4. To limit further movement of the telescopic tube 2, when it is necessary to lock the position of the telescopic tube 2 for a long time, the operator rotates the rotating sleeve 13, and the internal gear ring 14 on the rotating sleeve 13 drives the gear 17 meshing with it to rotate, and the gear 17 drives the screw 16 to rotate. Since the screw 16 is threadedly connected to the locking sleeve 18, the locking sleeve 18 will move up and down along the outer wall of the limiting sleeve 5. When the locking sleeve 18 moves up, the locking block 19 will enter the locking hole 20 on the arc rod 7, further fixing the position of the arc rod 7 and enhancing the limiting effect. Conversely, when the locking sleeve 18 moves down, the locking block 19 disengages from the locking hole 20, and the locked state is released.

[0040] When the rotating sleeve 13 rotates, the positioning block 30 will try to enter the positioning groove 29 on the outer wall of the limiting sleeve 5 under the action of the push spring 31. When the positioning block 30 enters the positioning groove 29, the position of the rotating sleeve 13 is fixed, thereby achieving precise control of the locking device. If the position needs to be adjusted, it is only necessary to apply sufficient force to overcome the pressure of the push spring 31 to disengage the positioning block 30 from the positioning groove 29, and then the position of the rotating sleeve 13 can be readjusted.

[0041] In all the schemes mentioned above, the connection between the two components can be selected according to actual conditions by welding, bolt and nut connection, bolt or screw connection or other well-known connection methods, which will not be listed here one by one. In the above, all fixed connections are preferably welded. Although the embodiments of the present invention have been shown and described, it can be understood by ordinary technicians in this field that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the attached claims and their equivalents.

Claims

1. A crane telescopic arm limiting mechanism, comprising a sleeve (1), characterized in that: A telescopic tube (2) is slidably provided in the sleeve (1), and a limiting device is provided in the sleeve (1), the limiting device comprising a center rod (3), a fixing sleeve (4), a limiting sleeve (5), a sliding hole (6), an arc rod (7), a push plate (8), a clamping block (9) and a clamping groove (10), the center rod (3) is installed in the sleeve (1), the fixing sleeve (4) is installed on the center rod (3), the limiting sleeve (5) is installed in the telescopic tube (2), and the sliding hole (6) is provided with a plurality of groups of On the outside of the limiting sleeve (5), the arc rod (7) is slidably installed in multiple groups of the sliding holes (6), the push plate (8) is set in the limiting sleeve (5), the clamping block (9) is installed at the bottom end of multiple groups of the arc rods (7), and multiple groups of the clamping grooves (10) are distributed on the outer wall of the fixed sleeve (4). Guide wheels (11) are installed at both ends of the sleeve (1), and guide cables (12) are provided on multiple groups of the guide wheels (11). Multiple groups of the guide cables (12) are connected to the side wall of the telescopic tube (2).

2. The crane telescopic arm limiting mechanism according to claim 1, characterized in that: The outer wall of the limiting sleeve (5) is provided with a locking device, and the locking device comprises a rotating sleeve (13), an inner gear ring (14), a support block (15), a screw (16), a gear (17), a locking sleeve (18), a locking block (19) and a locking hole (20). The rotating sleeve (13) is rotatably mounted on the bottom end of the limiting sleeve (5), the inner gear ring (14) is mounted on the top surface of the rotating sleeve (13), and the support block (15) is provided with a plurality of groups of locking members mounted on the outer surface of the limiting sleeve (5). The screw rod (16) is provided with multiple groups and is respectively rotatably mounted on multiple groups of the support blocks (15); the gear (17) is installed at the bottom end of the multiple groups of the screw rod (16) and meshes with the inner gear ring (14); the locking sleeve (18) slides on the outer wall of the limiting sleeve (5) and is threadedly connected with the multiple groups of the screw rod (16); the locking block (19) is provided with multiple groups and is installed on the top surface of the locking sleeve (18); and the locking hole (20) is provided on the multiple groups of the arc rod (7).

3. The crane telescopic arm limiting mechanism according to claim 2, characterized in that: The inner wall of the limiting sleeve (5) is provided with a positioning strip (21), and the outer wall of the fixing sleeve (4) is provided with a strip groove (22). The positioning strips (21) and the strip grooves (22) are both provided in multiple groups and are slidably connected.

4. A crane telescopic arm limiting mechanism according to claim 3, characterized in that: multiple groups The sliding holes (6) are each provided with a sliding groove (23), and the outer walls of the plurality of groups of arc-shaped rods (7) are each provided with a sliding bar (24), and the plurality of groups of sliding bars (24) are respectively slidably connected to the plurality of groups of sliding grooves (23).

5. A crane telescopic arm limiting mechanism according to claim 4, characterized in that: multiple groups The top ends of the arc-shaped rods (7) are all provided with push blocks (25), and a plurality of groups of push blocks (25) are connected to the inner wall of the limiting sleeve (5) with a resisting spring (26).

6. The crane telescopic arm limiting mechanism according to claim 5, characterized in that: A compression spring (27) is connected between the push plate (8) and the inner top surface of the limiting sleeve (5), and multiple groups of the compression springs (27) are provided.

7. The crane telescopic arm limiting mechanism according to claim 6, characterized in that: A connecting disk (28) is installed in the telescopic tube (2), and the connecting disk (28) is slidably connected to the center rod (3).

8. The crane telescopic arm limiting mechanism according to claim 7, characterized in that: The rotating sleeve (13) is provided with a positioning device, which includes a positioning groove (29), a positioning block (30) and a push spring (31). The positioning groove (29) is provided with multiple groups distributed on the outer wall of the limiting sleeve (5), the positioning block (30) is provided with multiple groups and is slidably installed on the rotating sleeve (13), and the push spring (31) is provided with multiple groups and its two ends are respectively connected to the outer wall of the rotating sleeve (13) and the top of the multiple groups of positioning blocks (30).

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