Three-section movable outrigger system, telescoping control method and wheel crane

Abstract

The application discloses a three-section movable supporting leg system, a control method and a wheel type crane, and relates to the technical field of cranes.The three-section movable supporting leg system comprises a fixed supporting leg, a horizontal telescopic cylinder and a three-section movable supporting leg mechanism, the three-section movable supporting leg mechanism comprises a first movable supporting leg, a second movable supporting leg and a third movable supporting leg, the cylinder barrels of the horizontal telescopic cylinder are arranged on the first movable supporting leg, the horizontal telescopic cylinder comprises a first telescopic cylinder and a second telescopic cylinder, the first telescopic cylinder is used to push out the three-section movable supporting leg mechanism, and the second telescopic cylinder is used to push out the second movable supporting leg and the third movable supporting leg.The three-section movable supporting leg system has the advantages that control is simple, stability is good, weight is relatively light, manufacturing cost is relatively low, the lateral span of the whole vehicle can be increased on the basis of ensuring the width of the vehicle, and the lifting stability of the crane is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of movable outrigger technology for large machinery, and in particular to a three-section movable outrigger system, control method, and wheeled crane. Background Technology

[0002] Large construction machinery, such as wheeled cranes, are typically equipped with four outriggers. During lifting operations, these four outriggers extend to support the entire crane and bear the full weight of the load. As the tonnage of a wheeled crane increases, the required outrigger span for overall stability also increases. To improve the crane's stability during lifting, it is necessary to maximize the outrigger span, which necessitates increasing the extended length of the outriggers. Previously, wheeled cranes mostly used single-section or double-section outriggers; however, their maximum lateral span is no longer sufficient to meet operational requirements. Therefore, three-section outrigger structures have emerged in the industry. However, current three-section outriggers suffer from problems such as complex control systems, lower stability, greater weight, and higher cost.

[0003] For example, Chinese utility model patent CN215946580U (published on March 4, 2022) discloses a three-section movable outrigger whose telescopic system uses three independent horizontal cylinders to achieve the telescopic operation of the outrigger. However, this telescopic system has a complex structure and high cost. The three-section movable outrigger telescopic system, composed of three independent horizontal cylinders, requires three media—liquid, gas, and electricity—to provide power, controlling the telescopic operation of the horizontal cylinders in sequence. This telescopic system is not only heavy and costly, but also difficult to control sequentially and has low reliability. Furthermore, this telescopic system occupies a significant amount of internal space within the box-shaped structure, which is detrimental to pipeline layout, easily causing pipeline wear and increasing the probability of oil leakage. In addition, the connection between the three independent horizontal cylinders and between them and the outrigger structure, as well as the pipeline assembly process, are poor and costly.

[0004] For example, the three-section horizontal telescopic outrigger telescopic system disclosed in European Patent Office Patent Publication No. EP4001199A1 (published on May 25, 2022) uses a combination of multi-stage horizontal telescopic cylinders and rope mechanisms to achieve outrigger telescopic operation. However, in a three-section movable outrigger telescopic system composed of multi-stage horizontal telescopic cylinders and rope mechanisms, the multi-stage telescopic cylinders require high machining precision for the cylinder barrel and cylinder rod, making it difficult to guarantee dimensional and positional tolerances. When the telescopic cylinder extends or retracts, if the support ring of the upper cylinder barrel and the lower cylinder rod are too tightly fitted and the friction is too great, it can easily cause disordered extension and retraction of the hydraulic cylinder. Moreover, the stability of the multi-stage telescopic cylinder cylinder rod is poor, mainly used in applications with low power requirements and short strokes, and is not suitable for heavy machinery. At the same time, the rope mechanism compresses the height of the two-section and three-section movable outrigger box, reducing the load-bearing capacity of the outrigger structure. In addition, the rope mechanism is relatively complex, difficult to install, has a high failure rate, and is inconvenient for disassembly and maintenance, increasing the reliability risks of the telescopic system. Summary of the Invention

[0005] Purpose of the invention: The first purpose of the invention is to provide a three-section movable outrigger system that is simple to control, has good stability, is lightweight, and has low manufacturing cost. The second purpose of the invention is to provide a telescopic control method for the three-section movable outrigger system. The third purpose of the invention is to provide a wheeled crane that uses the above-mentioned three-section movable outrigger system.

[0006] Technical Solution: The present invention provides a three-section movable outrigger system, comprising a fixed outrigger, a horizontal telescopic cylinder, and a three-section movable outrigger mechanism. The three-section movable outrigger mechanism includes a first movable outrigger, a second movable outrigger, and a third movable outrigger. The cylinders of the horizontal telescopic cylinder are all disposed on the first movable outrigger. The horizontal telescopic cylinder includes a first telescopic cylinder and a second telescopic cylinder. The first telescopic cylinder is used to extend the three-section movable outrigger mechanism, and the second telescopic cylinder is used to extend the second and third movable outriggers. A support portion is provided on the outer side of the third movable outrigger.

[0007] The horizontal telescopic cylinder can be any type of electric cylinder, pneumatic cylinder, hydraulic cylinder, etc.

[0008] Furthermore, the first telescopic cylinder and the second telescopic cylinder are arranged vertically, the cylinder rod of the first telescopic cylinder is fixedly connected to the fixed support leg, the cylinder rod of the second telescopic cylinder is fixedly connected to the third movable support leg, and the second movable support leg is provided with a horizontal telescopic cylinder wheel.

[0009] Furthermore, the second movable leg is provided with an inner stop block on one side and a front stop block at the front end. The front stop block cooperates with the top protrusion of the support part. The third movable leg is provided with an outer stop block on one side that cooperates with the inner stop block.

[0010] The inner and outer blocks can be respectively installed on the upper cover plates of the second and third movable legs, or on the left and right web plates of the second and third movable legs.

[0011] Furthermore, the fixed support leg, the first movable support leg, the second movable support leg, and the third movable support leg are all box-shaped structures; the fixed support leg includes a fixed support leg body, and the fixed support leg body is provided with a first door panel assembly and a lower overlapping block for supporting the first movable support leg; the second movable support leg includes a second movable support leg body, and the third movable support leg includes a third movable support leg body, and the second movable support leg body is provided with a second door panel assembly and a lower pad block for supporting the third movable support leg body, the second door panel assembly includes two symmetrical second door panels and a connecting plate, the front stop is disposed on the connecting plate, and the top of the third movable support leg body is provided with a stop corresponding to the second door panel.

[0012] Furthermore, the second movable leg is provided with second door panels on both sides, and the third movable leg is provided with a stop block on the outer side of the main body that cooperates with the second door panels.

[0013] Furthermore, the inner and / or outer blocks are provided with vibration damping blocks.

[0014] Furthermore, the stroke of the second telescopic cylinder is L, and when the three-section movable outrigger mechanism is not extended, the horizontal distance between the inner block and the outer block is L1, and when the three-section movable outrigger mechanism is fully extended, the horizontal distance between the front block and the support is L2, where L1=L2=L / 2.

[0015] Furthermore, the first telescopic cylinder and the second telescopic cylinder are hydraulic cylinders; the large chamber of the first telescopic cylinder and the large chamber of the second telescopic cylinder are connected, and a first sequence valve is provided on the connecting oil line; the small chamber of the first telescopic cylinder and the small chamber of the second telescopic cylinder are connected, and a second sequence valve is provided on the connecting oil line; a first oil inlet is provided on the large chamber of the first telescopic cylinder, and a second oil inlet is provided on the small chamber of the second telescopic cylinder.

[0016] Furthermore, the support portion is a vertical telescopic cylinder.

[0017] The present invention provides a control method for a three-section movable outrigger, applied to the three-section movable outrigger system described above. The first telescopic cylinder rod extends, driving the three-section movable outrigger mechanism to extend; the second telescopic cylinder rod extends, sequentially driving the third movable outrigger and the second movable outrigger to extend; the second telescopic cylinder rod retracts, sequentially driving the third movable outrigger and the second movable outrigger to retract; the first telescopic cylinder rod retracts, driving the three-section movable outrigger mechanism to retract.

[0018] Furthermore, the first telescopic cylinder and the second telescopic cylinder are hydraulic cylinders;

[0019] The first telescopic cylinder rod extends, driving the three-section movable outrigger mechanism to extend, including: during the extension of the first telescopic cylinder rod, the pressure in the large chamber of the first telescopic cylinder is lower than the opening value of the first sequence valve, no pressure oil enters the second telescopic cylinder, and the three-section movable outrigger mechanism is in the fully retracted state, and the first telescopic cylinder rod pushes the three-section movable outrigger mechanism to extend outward as a whole.

[0020] The second telescopic cylinder rod extends, sequentially driving the third movable leg and the second movable leg to extend. This includes: when the first telescopic cylinder rod extends to its maximum stroke, oil continues to flow into the first oil inlet. When the pressure value of the first sequence valve opening is reached, the pressurized oil added from the first oil inlet enters the large chamber of the upper horizontal second telescopic cylinder, and the piston of the second telescopic cylinder extends outward, driving the third movable leg to extend. When the second telescopic cylinder extends halfway, the outer stop on the third movable leg abuts against the inner stop on the second movable leg, and the second telescopic cylinder rod continues to extend outward, driving the second and third movable legs to extend together until the three-section movable leg mechanism is in a fully extended state, reaching the maximum lateral span.

[0021] The second telescopic cylinder rod retracts, which in turn drives the third movable leg and the second movable leg to retract in sequence. This includes: the second telescopic cylinder rod retracts, which drives the third movable leg to retract. When the second telescopic cylinder retracts half of its stroke, the support part contacts the front stop block on the second movable leg. When the second telescopic cylinder continues to retract inward, it drives the second movable leg and the third movable leg to retract together until the three-section movable leg mechanism is in a fully retracted state.

[0022] The retraction of the first telescopic cylinder rod causes the three-section movable outrigger mechanism to retract. This includes: during the retraction of the second telescopic cylinder rod, the pressure in the small chamber of the second telescopic cylinder is lower than the opening value of the second sequence valve, so no pressurized oil enters the first telescopic cylinder, which is in a fully extended state. When the second telescopic cylinder rod is fully retracted, oil continues to enter through the second oil inlet. When the pressure reaches the opening pressure value of the second sequence valve, the pressurized oil added from the second oil inlet enters the small chamber of the first telescopic cylinder, causing the first telescopic cylinder to retract inward. The fully retracted three-section movable outrigger mechanism retracts together to the starting position.

[0023] The present invention provides a wheeled crane in which the movable outriggers adopt a three-section movable outrigger system as described above.

[0024] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) The present invention further increases the lateral span of the outriggers and effectively improves the stability of the entire machine while the overall weight is lighter and the manufacturing cost is lower; (2) The setting of each stop block in the present invention does not occupy the space of the movable outrigger box, which maximizes the height of the movable outrigger box and improves the load-bearing capacity and reliability of the outrigger structure; (3) The horizontal telescopic system of the present invention has a simple structure, increases the space for the arrangement of pipelines / wiring harnesses inside the outrigger box, and improves the reliability of pipelines and lines; (4) The horizontal telescopic cylinder of the present invention is assembled from two conventional single-cylinder rod telescopic cylinders. Compared with multi-stage cylinders, it is simple to process, has strong cylinder rod stability, can meet the long outrigger span stroke requirements, and has a lower cost. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of the three-section movable support leg system of the present invention;

[0026] Figure 2 This is a schematic diagram of the fixed support leg structure of the present invention;

[0027] Figure 3 This is a schematic diagram of the second and third legs of the present invention in their fully retracted state.

[0028] Figure 4 This is a schematic diagram of the second and third legs of the present invention in their fully extended states.

[0029] Figure 5 This is a schematic diagram of the overall structure of the present invention in its fully extended state;

[0030] Figure 6 This is a schematic diagram of the overall structure of the present invention in its fully collapsed state;

[0031] Figure 7 This is a schematic diagram of the overall structure of the present invention in its non-extended state;

[0032] Figure 8 This is a schematic diagram of the overall structure of the present invention in its first extended state;

[0033] Figure 9 This is a schematic diagram of the second extended state of the overall structure of the present invention;

[0034] Figure 10 This is a schematic diagram of the overall structure of the present invention in its third extended state;

[0035] Figure 11 This is a schematic diagram of the system when the horizontal telescopic cylinder of the present invention is a hydraulic cylinder;

[0036] Figure 12 This is a schematic diagram of the structure of the horizontal telescopic cylinder of the present invention when it is a hydraulic cylinder. Detailed Implementation

[0037] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0038] The three-section movable outrigger system and its control method of the present invention are described in reference. Figure 1-6 It includes a fixed support leg 1, a horizontal telescopic cylinder 2, and a three-section movable support leg mechanism. The three-section movable support leg mechanism includes a first movable support leg 3, a second movable support leg 4, and a third movable support leg 5. The cylinders of the horizontal telescopic cylinder 2 are all mounted on the first movable support leg 3. The horizontal telescopic cylinder 2 includes a first telescopic cylinder 21 and a second telescopic cylinder 22. The first telescopic cylinder 21 is used to extend the three-section movable support leg mechanism, and the second telescopic cylinder is used to extend the second movable support leg 4 and the third movable support leg 5. A support part 6 is provided on the outer side of the three movable support legs 5.

[0039] refer to Figure 7-10The first telescopic cylinder 21 is controlled to extend, thereby extending the three-section movable outrigger mechanism; the second telescopic cylinder 22 is controlled to extend, thereby extending the third movable outrigger 5 and the second movable outrigger 4 in sequence; the second telescopic cylinder 22 is controlled to retract, thereby retracting the third movable outrigger 5 and the second movable outrigger 4 in sequence; the first telescopic cylinder 21 is controlled to retract, thereby retracting the three-section movable outrigger mechanism.

[0040] In some embodiments, the horizontal telescopic cylinder 2 is mounted on the first movable support leg 3 via a fixing pin 8. The first telescopic cylinder 21 and the second telescopic cylinder 22 are arranged vertically, with the cylinder barrel of the first telescopic cylinder 21 positioned directly below the cylinder barrel of the second telescopic cylinder 22. The fixed support leg 1 is provided with a horizontal telescopic cylinder seat 12. The cylinder rod of the first telescopic cylinder 21 is fixedly connected to the horizontal telescopic cylinder seat 12 via a rear pin 7. The third movable support leg 5 is provided with a telescopic cylinder front mounting hole 53. The cylinder rod of the second telescopic cylinder 22 is fixedly connected to the third movable support leg 5 via a front pin 9 and the telescopic cylinder front mounting hole 53. The second movable support leg 4 is provided with a drag wheel 10 for the horizontal telescopic cylinder 2. The second movable support leg 4 has an inner stop block 42 on one side and a front stop block 45 at the front end, with the front stop block 45 cooperating with the support part 6. The third movable support leg 5 has an outer stop block 52 on one side that cooperates with the inner stop block 42. The fixed support leg 1, the first movable support leg 3, the second movable support leg 4, and the third movable support leg 5 are all box-type structures. The fixed support leg 1 includes a fixed support leg body 11, on which a first door panel assembly 14 and a lower overlapping block 13 are provided for supporting the first movable support leg 3. The second movable support leg 4 includes a second movable support leg body 41, and the third movable support leg 5 includes a third movable support leg body 51. The second movable support leg body 41 is provided with a second door panel assembly and a lower pad block 47 for supporting the third movable support leg body 51. The second door panel assembly includes two symmetrical second door panels 43 and a connecting plate 44. A front stop block 45 is provided on the connecting plate 44. The second movable support leg body 41 is also provided with a drag cylinder wheel mounting hole 46. The inner stop block 42 and / or the outer stop block 52 are provided with vibration damping blocks. The support part 6 is a vertical telescopic cylinder. The stroke of the second telescopic cylinder is L. When the three-section movable outrigger mechanism is not extended, the horizontal distance between the inner block and the outer block is L1. When the three-section movable outrigger mechanism is fully extended, the horizontal distance between the front block and the support part is L2. L1=L2=L / 2.

[0041] In some embodiments, reference Figure 1-12 The first telescopic cylinder 21 and the second telescopic cylinder 22 are hydraulic cylinders; the large chamber of the first telescopic cylinder 21 and the large chamber of the second telescopic cylinder 22 are connected, and a first sequence valve 231 is provided on the connecting oil line; the small chamber of the first telescopic cylinder 21 and the small chamber of the second telescopic cylinder 22 are connected, and a second sequence valve 232 is provided on the connecting oil line; a first oil inlet 211 is provided on the large chamber of the first telescopic cylinder 21, and a second oil inlet 221 is provided on the small chamber of the second telescopic cylinder 22.

[0042] The telescopic control method is as follows: During the extension of the first telescopic cylinder 21, the pressure in the large chamber of the first telescopic cylinder 21 is lower than the opening value of the first sequence valve 231, and no pressurized oil enters the second telescopic cylinder 22, which is in the fully retracted state of the three-section movable outrigger mechanism. The cylinder rod of the first telescopic cylinder 21 pushes the three-section movable outrigger mechanism to extend outward as a whole. When the cylinder rod of the first telescopic cylinder 21 extends to the maximum stroke, oil continues to enter through the first oil inlet 211. When the opening pressure value of the first sequence valve 231 is reached, the pressurized oil added from the first oil inlet 211 enters the large chamber of the upper horizontal second telescopic cylinder 22, and the piston of the second telescopic cylinder 22 extends outward, driving the third movable outrigger 5 to extend. When the second telescopic cylinder 22 extends halfway, the outer stop 52 on the third movable outrigger 5 abuts against the inner stop 42 on the second movable outrigger 4, and the cylinder rod of the second telescopic cylinder 22 continues to extend outward, driving the second movable outrigger 4 and the third movable outrigger 5 to extend together until the three-section movable outrigger mechanism is in the fully extended state. The second telescopic cylinder 22 retracts, causing the third movable outrigger 5 to retract. When the second telescopic cylinder 22 retracts halfway, the support part 6 contacts the front stop 45 on the second movable outrigger 4. As the second telescopic cylinder 22 continues to retract inward, it causes the second movable outrigger 4 and the third movable outrigger 5 to retract together until the three-section movable outrigger mechanism is in a fully retracted state. During the retraction of the second telescopic cylinder 22, the pressure in the small chamber of the second telescopic cylinder 22 is lower than the opening value of the second sequence valve 232. No pressure oil enters the first telescopic cylinder 21, which is in a fully extended state. When the second telescopic cylinder 22 retracts completely, oil continues to enter through the second oil inlet 221. When the pressure value of the second sequence valve 232 is reached, the pressure oil added from the second oil inlet 221 enters the small chamber of the first telescopic cylinder 21, and the first telescopic cylinder 21 retracts inward. The fully retracted three-section movable outrigger mechanism retracts together to the starting position. At this time, the outermost part of the third movable outrigger 5 does not extend beyond the outermost end of the vehicle.

[0043] The present invention provides a wheeled crane with four movable outriggers, all of which adopt the above-mentioned three-section movable outrigger system.

Claims

1. A three-section movable outrigger system, characterized in that, It includes a fixed support leg (1), a horizontal telescopic cylinder (2) and a three-section movable support leg mechanism. The three-section movable support leg mechanism includes a first movable support leg (3), a second movable support leg (4) and a third movable support leg (5). The cylinder of the horizontal telescopic cylinder (2) is mounted on the first movable support leg (3). The horizontal telescopic cylinder (2) includes a first telescopic cylinder (21) and a second telescopic cylinder (22). The first telescopic cylinder (21) is used to push out the three-section movable support leg mechanism, and the second telescopic cylinder is used to push out the second movable support leg (4) and the third movable support leg (5). The third movable support leg (5) has a support part (6) on its outer side. The first telescopic cylinder (21) and the second telescopic cylinder (22) are arranged vertically. The cylinder rod of the first telescopic cylinder (21) is fixedly connected to the fixed support leg (1), and the cylinder rod of the second telescopic cylinder (22) is fixedly connected to the third movable support leg (5). The second movable support leg (4) is provided with the drag wheel (10) of the horizontal telescopic cylinder (2). The second movable support leg (4) has an inner stop block (42) on one side and a front stop block (45) at the front end. The front stop block (45) cooperates with the top protrusion of the support part (6). The third movable support leg (5) has an outer stop block (52) on one side that cooperates with the inner stop block (42). The fixed support leg (1), the first movable support leg (3), the second movable support leg (4), and the third movable support leg (5) are all box-shaped structures. The fixed support leg (1) includes a fixed support leg body (11), and the fixed support leg body (11) is provided with a first door panel assembly (14) for supporting the first movable support leg (3) and a lower overlapping block (13). The second movable support leg (4) includes a second movable support leg body (41), and the third movable support leg (5) includes a third movable support leg body (51). The second movable support leg body (41) is provided with a second door panel assembly for supporting the third movable support leg body (51) and a lower pad block (47). The second door panel assembly includes two symmetrical second door panels (43) and a connecting plate (44). The front stop block (45) is set on the connecting plate (44), and the top of the third movable support leg body (51) is provided with a stop block corresponding to the second door panel (43).

2. The three-section movable outrigger system according to claim 1, characterized in that, The second movable support leg (4) has a second door panel (43) on both sides, and the third movable support leg body (51) has a stop block on the outside that cooperates with the second door panel (43).

3. The three-section movable outrigger system according to claim 1, characterized in that, The inner stop block (42) and / or the outer stop block (52) are provided with vibration damping blocks.

4. The three-section movable outrigger system according to claim 1, characterized in that, The stroke of the second telescopic cylinder (22) is L. When the three-section movable support leg mechanism is not extended, the horizontal distance between the inner stop block (42) and the outer stop block (52) is L1. When the three-section movable support leg mechanism is fully extended, the horizontal distance between the front stop block (45) and the support part (6) is L2. L1=L2=L / 2.

5. The three-section movable outrigger system according to claim 1, characterized in that, The first telescopic cylinder (21) and the second telescopic cylinder (22) are hydraulic cylinders; the large cavity of the first telescopic cylinder (21) and the large cavity of the second telescopic cylinder (22) are connected, and a first sequence valve (231) is provided on the connecting oil line; the small cavity of the first telescopic cylinder (21) and the small cavity of the second telescopic cylinder (22) are connected, and a second sequence valve (232) is provided on the connecting oil line; a first oil inlet (211) is provided on the large cavity of the first telescopic cylinder (21), and a second oil inlet (221) is provided on the small cavity of the second telescopic cylinder (22).

6. The three-section movable outrigger system according to claim 1, characterized in that, The support part (6) is a vertical telescopic cylinder.

7. A telescopic control method for a three-section movable outrigger system according to any one of claims 1-6, characterized in that, include: The first telescopic cylinder (21) extends its rod, driving the three-section movable support leg mechanism to extend; The second telescopic cylinder (22) extends its cylinder rod, which in turn drives the third movable leg (5) and the second movable leg (4) to extend in sequence; the second telescopic cylinder (22) retracts its cylinder rod, which in turn drives the third movable leg (5) and the second movable leg (4) to retract in sequence; the first telescopic cylinder (21) retracts its cylinder rod, which drives the three-section movable leg mechanism to retract.

8. The telescopic control method for the three-section movable outrigger system according to claim 7, characterized in that, The first telescopic cylinder (21) and the second telescopic cylinder (22) are hydraulic cylinders; The first telescopic cylinder (21) extends its cylinder rod, driving the three-section movable outrigger mechanism to extend, including: during the extension process of the first telescopic cylinder (21), the pressure in the large chamber of the first telescopic cylinder (21) is lower than the opening value of the first sequence valve (231), the second telescopic cylinder (22) has no pressure oil entering, and is in the fully retracted state of the three-section movable outrigger mechanism, and the cylinder rod of the first telescopic cylinder (21) pushes the three-section movable outrigger mechanism to extend outward as a whole; The piston rod of the second telescopic cylinder (22) extends, which in turn drives the third movable leg (5) and the second movable leg (4) to extend in sequence. This includes: when the piston rod of the first telescopic cylinder (21) extends to the maximum stroke, oil continues to enter the first oil inlet (211). When the opening pressure value of the first sequence valve (231) is reached, the pressure oil added from the first oil inlet (211) enters the large chamber of the upper horizontal second telescopic cylinder (22), and the piston of the second telescopic cylinder (22) extends outward, driving the third movable leg (5) to extend. When the second telescopic cylinder (22) extends half of its stroke, the outer stop (52) on the third movable leg (5) abuts against the inner stop (42) on the second movable leg (4), and the piston rod of the second telescopic cylinder (22) continues to extend outward, driving the second movable leg (4) and the third movable leg (5) to extend together until the three movable leg mechanism is in the fully extended state, reaching the maximum lateral span. The second telescopic cylinder (22) retracts, which in turn drives the third movable support leg (5) and the second movable support leg (4) to retract in sequence. This includes: the second telescopic cylinder (22) retracts, which drives the third movable support leg (5) to retract. When the second telescopic cylinder (22) retracts half of its stroke, the support part (6) contacts the front stop block (45) on the second movable support leg (4). When the second telescopic cylinder (22) continues to retract inward, it drives the second movable support leg (4) and the third movable support leg (5) to retract together until the three-section movable support leg mechanism is in a fully retracted state. The first telescopic cylinder (21) retracts its cylinder rod, causing the three-section movable outrigger mechanism to retract. This includes: during the retraction of the cylinder rod of the second telescopic cylinder (22), the pressure in the small chamber of the second telescopic cylinder (22) is lower than the opening value of the second sequence valve (232). No pressure oil enters the first telescopic cylinder (21), which is in a fully extended state. When the cylinder rod of the second telescopic cylinder (22) is fully retracted, oil continues to enter through the second oil inlet (221). When the opening pressure value of the second sequence valve (232) is reached, the pressure oil added from the second oil inlet (221) enters the small chamber of the first telescopic cylinder (21), and the first telescopic cylinder (21) retracts inward. The fully retracted three-section movable outrigger mechanism retracts together to the starting position.

9. A wheeled crane, comprising movable outriggers, characterized in that, The movable outrigger adopts a three-section movable outrigger system as described in any one of claims 1-4.

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