A boom for a working machine

Abstract

The application discloses a kind of for the hoist arm on working machine, including main arm and vice arm;Main arm includes main base arm and main telescopic arm, main telescopic arm can retract inside main base arm or extend outside main base arm;Vice arm is used to hoist heavy object, vice arm can rotate relative to main arm, vice arm includes vice base arm and vice telescopic arm, vice telescopic arm can retract inside vice base arm or extend outside vice base arm.The application can be supported using main arm, vice arm is used as working arm to hoist work, to adjust the overall position of hoist arm using vice arm;And main arm and vice arm can be telescopic, on the one hand, main telescopic arm and / or vice telescopic arm can be adjusted according to actual demand, in turn, the length of hoist arm is adjusted, to adapt to different working height and distance requirement, provide better flexibility and greater working range in different working environment.

Description

Technical Field

[0001] This invention belongs to the field of engineering machinery technology, specifically a lifting boom used in operating machinery. Background Technology

[0002] Construction machinery, such as cranes and hoists, is widely used in various fields such as construction, bridges, power, and ports, mainly for lifting and moving heavy objects. As the core component of construction machinery, the performance of the boom directly affects the machine's operating efficiency and safety. Traditional booms typically consist of a main boom and a jib, with the boom's extension and retraction achieved through hydraulic cylinders to adapt to different operational needs and environments.

[0003] Existing crane boom designs typically employ a main boom and a secondary boom structure, with the secondary boom usually featuring a truss structure that serves only as auxiliary support, primarily enhancing the stability of the crane boom under load. This design introduces limitations in terms of operating range and lifting flexibility.

[0004] Furthermore, with the increasing complexity and diversification of engineering projects, existing crane booms are difficult to design in a way that balances a large operating range with high flexibility, especially when precise operation is required in space-constrained environments. This not only limits the application scope of the machinery but also increases safety hazards during operation.

[0005] Furthermore, although the main boom and auxiliary boom of a traditional crane can be retracted when not in use, the auxiliary boom only has an auxiliary support function and its extension and rotation capabilities are limited, which makes it impossible to achieve efficient adjustment and flexible operation when it is necessary to expand the working range. Summary of the Invention

[0006] The purpose of this invention is to provide a lifting boom with a larger operating range and better flexibility for use on operating machinery.

[0007] The crane boom provided by this invention for use in operating machinery includes a main boom and a secondary boom; the main boom includes a main base boom and a main telescopic boom, the main telescopic boom being able to retract into the main base boom or extend out of the main base boom; the secondary boom is used for lifting heavy objects, the secondary boom being able to rotate relative to the main boom, the secondary boom including a secondary base boom and a secondary telescopic boom, the secondary telescopic boom being able to retract into the secondary base boom or extend out of the secondary base boom.

[0008] In one embodiment of the above-mentioned crane boom, the main telescopic boom includes multiple main boom sections. Among two adjacent main boom sections, the main boom section farther from the main base boom can extend or retract to the main boom section closest to the main base boom. The main boom section farthest from the main base boom among the multiple main boom sections is rotatably connected to the auxiliary base boom.

[0009] In an embodiment of the above crane boom, the auxiliary boom has a parallel position and an extended position along a rotation direction of the auxiliary boom; when the auxiliary boom is in the parallel position, the main boom and the auxiliary boom are arranged side by side along a second direction in a projection along a first direction; when the auxiliary boom is in the extended position, the main boom and the auxiliary boom are arranged in extension along a third direction in the projection along the first direction, the first direction, the second direction and the third direction being perpendicular to each other.

[0010] In an embodiment of the above crane boom, the crane boom comprises an ear plate, a swing seat and a pin shaft; one of the ear plate and the swing seat is arranged on the main telescopic boom, and the other of the ear plate and the swing seat is arranged on the auxiliary base boom; the ear plate is formed with a slot and a first pin hole communicating with the slot, the swing seat is formed with a plug-in block, the plug-in block is formed with a second pin hole, and the plug-in block is inserted into the slot; the pin shaft is arranged through the first pin hole and the second pin hole to enable the auxiliary boom to rotate around the pin shaft.

[0011] In an embodiment of the above crane boom, the crane boom comprises a slewing reducer arranged on the main telescopic boom and configured to drive the auxiliary boom to rotate around the pin shaft.

[0012] In an embodiment of the above crane boom, the ear plate is formed with a clamping groove on a side thereof away from the slot along the second direction, the swing seat is formed with a clamping buckle on a side thereof away from the plug-in block along the second direction, and the clamping groove is in clamping engagement with the clamping buckle when the auxiliary boom is in the extended position.

[0013] In an embodiment of the above crane boom, the crane boom comprises a pin insertion oil cylinder arranged on the ear plate, a slot wall of the clamping groove is formed with a first insertion hole penetrating through along the first direction, the clamping buckle is formed with a second insertion hole penetrating through along the first direction, and a telescopic rod of the pin insertion oil cylinder is arranged through the first insertion hole and the second insertion hole in a state where the clamping buckle is located in the clamping groove.

[0014] In an embodiment of the above crane boom, the crane boom comprises a controller and a sensor, the controller is electrically connected with the sensor, the pin insertion oil cylinder and the slewing reducer, the controller is configured to control the slewing reducer to drive the swing seat to switch between the parallel position and the extended position, and the sensor is arranged in the clamping groove and configured to detect the clamping buckle, and the controller controls the pin insertion oil cylinder to insert or pull out the pin when the clamping buckle is detected to be located in the clamping groove.

[0015] In an embodiment of the above crane boom, a peripheral edge of the second insertion hole is formed with a guide groove, and the clamping buckle is arranged through the second insertion hole via the guide groove.

[0016] In an embodiment of the above crane boom, the crane boom comprises an auxiliary luffing oil cylinder telescopically supported on the auxiliary base boom.

[0017] The beneficial effects of the present application are:

[0018] The main arm can be used for support, and the auxiliary arm can be used as a working arm for hoisting work, so as to adjust the overall position of the hoisting arm by the auxiliary arm; and the main arm and the auxiliary arm can be telescopic, on the one hand, the main telescopic arm and / or the auxiliary telescopic arm can be adjusted according to actual needs, and then the length of the hoisting arm is adjusted to adapt to different working heights and distance requirements, to provide better flexibility and larger working range in different working environments; on the other hand, the main arm and the auxiliary arm can be retracted when not in use, reducing the occupied space of the hoisting arm, facilitating transportation and placement, which is particularly important for operation in a space-limited environment; at the same time, the auxiliary arm can rotate relative to the main arm, and the flexibility is further improved. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 A structural schematic diagram of a hoisting arm provided by an embodiment of the present application, wherein the auxiliary arm is in a parallel position, and the main telescopic arm and the auxiliary telescopic arm are in a retracted state;

[0020] Figure 2 A structural schematic diagram of the hoisting arm from another perspective; Figure 1

[0021] Figure 3 A structural schematic diagram of the hoisting arm from another perspective; Figure 1

[0022] Figure 4 A structural schematic diagram of a hoisting arm provided by another embodiment of the present application, wherein the auxiliary arm is in an unfolded position, and the main telescopic arm and the auxiliary telescopic arm are in a retracted state;

[0023] Figure 5 A structural schematic diagram of the hoisting arm from another perspective; Figure 4

[0024] Figure 6 A structural schematic diagram of a hoisting arm provided by another embodiment of the present application, wherein the auxiliary arm is in an unfolded position, and the main telescopic arm and the auxiliary telescopic arm are in an extended state.

[0025] REFERENCE SIGNS:

[0026] ​​​100, jib; 1, main arm; 11, main base arm; 12, main telescopic arm; 121, main joint arm; 2, auxiliary arm; 21, auxiliary base arm; 22, auxiliary telescopic arm; 221, auxiliary joint arm; 3, main luffing cylinder; 31, cylinder barrel of main luffing cylinder; 32, telescopic rod of main luffing cylinder; 4, ear plate; 41, insertion slot; 43, plate body; 44, rotating plate; 441, first plate; 442, second plate; 45, clamping slot; 45a, first insertion hole; 46, insertion plate; 461, third plate; 462, fourth plate; 5, swing seat; 51, insertion block; 53, seat body; 54, connecting ear; 55, clamping buckle; 55a, second insertion hole; 55b, guide slot; 56, buckling ear; 6, pin shaft; 7, slewing reducer; 8, auxiliary luffing cylinder; 81, cylinder barrel of auxiliary luffing cylinder; 82, telescopic rod of auxiliary luffing cylinder; 9, insertion pin cylinder; 91, cylinder barrel of insertion pin cylinder; 92, telescopic rod of insertion pin cylinder;

[0027] Figure 1 R1 in the formula (1) is a first direction; Figure 2 R2 in the formula (2) is a second direction; Figure 1 R3 in the formula (3) is a third direction; wherein the first direction, the second direction and the third direction are perpendicular to each other. DETAILED DESCRIPTION

[0028] The related technical solutions will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0029] With reference to Figures 1 to 6 The jib for the working machine disclosed in the embodiments comprises a main arm 1 and an auxiliary arm 2.

[0030] The main arm 1 comprises a main base arm 11 and a main telescopic arm 12, and the main telescopic arm can be retracted into the main base arm or extended out of the main base arm; the auxiliary arm 2 is used for hoisting heavy objects, and the auxiliary arm can rotate relative to the main arm, and the auxiliary arm comprises an auxiliary base arm 21 and an auxiliary telescopic arm 22, and the auxiliary telescopic arm can be retracted into the auxiliary base arm or extended out of the auxiliary base arm.

[0031] Therefore, the main arm 1 can be used for support, and the auxiliary arm 2 can be used as a working arm for hoisting work, so that the overall position of the jib can be adjusted by the auxiliary arm.

[0032] The main arm 1 and the auxiliary arm 2 are both capable of telescoping, so on the one hand, the main telescopic arm 12 and / or the auxiliary telescopic arm 22 can be adjusted according to actual needs, and then the length of the crane arm is adjusted to adapt to different working heights and distance requirements, so as to provide better flexibility and greater working range in different working environments; on the other hand, the main arm and the auxiliary arm can be retracted when not in use, so as to reduce the occupied space of the crane arm, facilitating transportation and placement, which is particularly important for operation in space-limited environments.

[0033] The auxiliary arm 2 is capable of rotating relative to the main arm 1, further improving flexibility.

[0034] The working machine of the embodiment can be a crane or a hoist.

[0035] In an embodiment, the working machine comprises a base and a turntable, the turntable is arranged on the base, the turntable is capable of rotating along a rotation center, and the telescopic arm can be arranged on the turntable. The telescopic arm can rotate with the turntable, improving the working range of the working machine.

[0036] In an embodiment, please refer to Figure 1 , Figure 5 and Figure 6 , the crane arm comprises a main luffing oil cylinder 3, which is telescopically supported between the main base arm 11 and the turntable.

[0037] For example, the cylinder barrel 31 of the main luffing oil cylinder can be rotatably connected with the turntable, and the telescopic rod 32 of the main luffing oil cylinder can be rotatably connected with the main base arm 11.

[0038] In this way, the angle between the main arm 1 and the turntable is adjusted by the telescoping of the main luffing oil cylinder 3, further improving the working range and flexibility of the crane arm.

[0039] In an embodiment, please refer to Figure 6 , the main telescopic arm 12 comprises a plurality of main section arms 121, the main section arm farther away from the main base arm 11 among two adjacent main section arms can be extended or retracted to the main section arm closer to the main base arm, and the main section arm farthest from the main base arm among the plurality of main section arms is rotatably connected with the auxiliary base arm 21.

[0040] For example, the main telescopic arm 12 can comprise five main section arms 121, the main section arm closest to the main base arm 11 among the five main section arms can be retracted into the main base arm or extended out of the main base arm, the main section arm farthest from the main base arm among the five main section arms is rotatably connected with the auxiliary base arm 21, and the main section arm farther away from the main base arm among two adjacent main section arms can be extended or retracted to the main section arm closer to the main base arm.

[0041] In this way, the plurality of main section arms 121 can be retracted or extended in sequence, further improving the extension length of the crane arm and the working range of the working machine.

[0042] In an embodiment, referring to Figure 6 , the auxiliary telescopic arm 22 can include at least one auxiliary section arm 221, which is telescopically arranged in the auxiliary base arm 21,

[0043] In this way, on the basis of the adjustment of the main arm 1, the working range of the crane arm 100 can be further improved by the extension or retraction of the auxiliary section arm 221, and the flexibility is strong.

[0044] In an embodiment, referring to Figure 2 and Figure 5 , the auxiliary arm 2 has a parallel position and an unfolded position along its rotation direction. When the auxiliary arm 2 is in the parallel position, the main arm 1 and the auxiliary arm 2 are arranged side by side along the second direction in the projection along the first direction. When the auxiliary arm 2 is in the unfolded position, the main arm 1 and the auxiliary arm 2 are arranged in extension along the third direction in the projection along the first direction.

[0045] It can be understood that the arrangement of the main arm 1 and the auxiliary arm 2 in extension along the third direction in the projection along the first direction means that the extension directions of the main arm 1 and the auxiliary arm 2 are the same, both extending in the third direction, and the main arm 1 is connected to one side of the auxiliary arm 2 along the third direction, so that the main arm 1 and the auxiliary arm 2 are coaxially arranged along the third direction.

[0046] When the crane arm is not working, the auxiliary arm 2 can be rotated to the parallel position, so that the main arm 1 and the auxiliary arm can be arranged side by side along the second direction in the projection along the second direction, that is, the auxiliary arm can be folded and arranged side by side with the main arm. In this way, the occupied space can be reduced, and transportation and placement are facilitated.

[0047] When the crane arm is working, the auxiliary arm can be rotated to the unfolded position, so that the main arm and the auxiliary arm can be arranged in extension along the third direction in the projection along the first direction, that is, the auxiliary arm can be unfolded and arranged in extension with the main arm. In this way, the extension length of the crane arm can be lengthened, the working range is wider, and the flexibility is strong.

[0048] In an embodiment, referring to Figures 1 to 3 , the crane arm includes an ear plate 4, a swing seat 5, a pin shaft 6 and a slewing reducer 7, one of the ear plate and the swing seat is arranged on the main telescopic arm 12, and the other of the ear plate and the swing seat is arranged on the auxiliary base arm 21, the ear plate is formed with a slot 41 and a first pin hole communicating with the slot, the swing seat is formed with an insertion block 51, the insertion block is formed with a second pin hole, and the insertion block is inserted in the slot. The pin shaft is arranged in the first pin hole and the second pin hole, so that the auxiliary arm 2 can rotate around the pin shaft.

[0049] For example, the swing seat 5 can be arranged on the auxiliary base arm 21 and rotationally connected thereto, and the ear plate 4 can be arranged on the main section arm farthest from the main base arm 11.

[0050] Specifically, the swing seat 5 comprises a seat body 53 and a connecting lug 54, the seat body is rotatably connected with the auxiliary base arm 21, the connecting lug is connected at one end of the seat body along the second direction, the other end of the connecting lug is protruded along the third direction away from the auxiliary base arm 21 and is inclined along the second direction away from the seat body, and the end of the connecting lug away from the seat body forms a plug 51, and the plug is formed with a second pin hole penetrating along the first direction.

[0051] The lug plate 4 comprises a plate body 43 and a rotating plate 44, the plate body can be connected on the main joint arm farthest from the main base arm 11 among the plurality of main joint arms 121, the rotating plate is arranged at one end of the plate body along the first direction, the rotating plate comprises a first plate 441 and a second plate 442, the first plate and the second plate are arranged at intervals along the first direction to define a plug slot 41, the first plate and the second plate are both formed with a first pin hole penetrating along the first direction, the plug 51 is inserted in the plug slot, and the pin shaft 6 is arranged in the second pin hole and the two first pin holes.

[0052] In this way, the auxiliary arm 2 can be supported by the swing seat 5, the pin shaft 6 and the lug plate 4 to rotate around the pin shaft, so that the auxiliary arm can be folded and unfolded, facilitating storage and transportation.

[0053] In an embodiment, as shown in Figures 1 to 3 , the number of the connecting lug 54, the rotating plate 44 and the pin shaft 6 can be two, the two connecting lugs are arranged at intervals along the first direction on both sides of the seat body 53, the two rotating plates are arranged at intervals along the first direction on both sides of the plate body 43, each plug 51 is inserted in the corresponding plug slot 41, and each pin shaft is arranged in the corresponding first pin hole and the second pin hole.

[0054] In this way, the stress and support of the auxiliary arm 2 can be enhanced, and the rotation stability is good.

[0055] In an embodiment, as shown in Figures 1 to 3 , the lifting arm comprises a slewing reducer 7, and the slewing reducer is arranged on the main telescopic arm 12 to drive the auxiliary arm 2 to rotate around the pin shaft 6.

[0056] For example, the slewing reducer 7 can be connected on the lug plate 4 of the main telescopic arm 12 to drive the auxiliary arm 2 to rotate around the pin shaft 6.

[0057] In this way, by arranging the slewing reducer 7 to drive the auxiliary arm 2 to rotate around the pin shaft 6, on the one hand, the slewing reducer can provide high torque output, ensuring that the auxiliary arm can rotate smoothly under heavy load; on the other hand, the slewing reducer has a high reduction ratio, so that the rotation of the auxiliary arm can be accurately controlled, improving the accuracy of operation; on the other hand, compared with the related art which drives the auxiliary arm to rotate by using a hydraulic motor and a connecting rod mechanism, the embodiment of the present application drives the auxiliary arm to rotate by using a slewing reducer, which has a compact structure and occupies a small space.

[0058] In an embodiment, please refer to Figure 1 , Figure 5 and Figure 6 , the jib includes a sub-luffing oil cylinder 8 which is telescopically supported on a sub-base arm 21.

[0059] Illustratively, the cylinder barrel 81 of the sub-luffing oil cylinder is rotatably arranged on a swing seat 5 on the sub-base arm 21, and the telescopic rod 82 of the sub-luffing oil cylinder is rotatably arranged on the sub-base arm. By the telescoping of the sub-luffing oil cylinder 8, the angle between the sub-arm 2 and the main arm 1 can be adjusted to achieve stepless adjustment.

[0060] In this way, not only can the operation range and flexibility of the jib be further improved, but also the adjustment of the angle can be accurately realized.

[0061] In an embodiment, the first direction can be the extension direction of the rotation axis of the pin shaft 6, and the third direction can be the telescoping direction of the main arm 1 or the telescoping direction of the sub-arm 2.

[0062] In an embodiment, please refer to Figure 3 and Figure 5 , the ear plate 4 is formed with a clamping groove 45 on the side thereof away from the slot 41 along the second direction, and the swing seat 5 is formed with a clamping buckle 55 on the side thereof away from the connecting ear 54 along the second direction. When the sub-arm 2 is in the unfolded position, the clamping groove and the clamping buckle are in clamping engagement.

[0063] Illustratively, the ear plate 4 includes a plug-in plate 46 which can be connected to the end of the plate body 43 away from the rotating plate 44 along the second direction. The plug-in plate includes a third plate 461 and a fourth plate 462 which are arranged in a spaced apart manner along the first direction to define the clamping groove 45.

[0064] The swing seat 5 includes a buckling ear 56 which can be connected to the end of the seat body 53 away from the connecting ear 54 along the second direction. The other end of the buckling ear extends away from the seat body along the third direction and is arranged in an inclined manner away from the seat body along the second direction, so that the projection shape of the swing seat 5 along the first direction is substantially in the shape of “〔”. The end of the buckling ear away from the seat body along the third direction is formed with the clamping buckle 55.

[0065] In this way, when the sub-arm 2 is in the unfolded position, the connecting ear 54 and the buckling ear 56 of the swing seat 5 can avoid the ear plate 4, so that the clamping buckle 55 can be inserted into the clamping groove 45, reducing the rotation of the sub-arm 2 during the operation of the jib, and the operation stability is good.

[0066] In an embodiment, please refer to Figure 3 and Figure 5The number of the insertion plates 46 and the number of the buckling ears 56 can be two, two insertion plates can be arranged at two sides of the plate body 43 along the first direction, and two buckling ears can be arranged at two sides of the seat body 53 along the first direction, and each buckle 55 can be inserted into the corresponding clamping groove 45.

[0067] In this way, the stress and support of the auxiliary arm 2 during work can be enhanced, and the work stability is good.

[0068] In an embodiment, referring to Figure 1 , Figure 3 and Figure 5 , the crane arm includes a latch oil cylinder 9 arranged on the lug plate 4, the slot wall of the clamping groove 45 is formed with a first insertion hole 45a penetrating along the first direction, the buckle 55 is formed with a second insertion hole 55a penetrating along the first direction, and the extension rod 92 of the latch oil cylinder is inserted into the first insertion hole and the second insertion hole in the state that the buckle is located in the clamping groove.

[0069] For example, the cylinder barrel 91 of the latch oil cylinder can be arranged at the middle of the two insertion plates 46 along the first direction. The third plate 461 and the fourth plate 462 are both formed with a first insertion hole 45a penetrating along the first direction, and the buckle 55 is formed with a second insertion hole 55a penetrating along the first direction.

[0070] In this way, in the state that the buckle 55 is located in the clamping groove 45, the extension rod 92 of the latch oil cylinder can be inserted into the first insertion hole 45a and the second insertion hole 55a to lock the auxiliary arm 2, further improve the stability of the auxiliary arm in the unfolded position, reduce the rotation of the auxiliary arm during the work of the crane arm, and further improve the work stability.

[0071] In an embodiment, referring to Figure 2 , the periphery of the second insertion hole 55a is formed with a guide groove 55b, and the buckle 55 is inserted into the second insertion hole through the guide groove.

[0072] For example, the periphery of the second insertion hole 55a is formed with a circular guide groove 55b.

[0073] In this way, since the caliber of the guide groove 55b is larger than the caliber of the second insertion hole 55a, when the buckle 55 is not inserted into the clamping groove 45 and the extension rod 92 of the latch oil cylinder is not aligned with the second pin hole, the extension rod of the latch oil cylinder can still be inserted into the second insertion hole through the guide of the guide groove; the guide groove helps to guide the extension rod of the latch oil cylinder to accurately correspond to the second insertion hole, ensures that the extension rod can be smoothly inserted into the pin hole, makes the installation process more easy, and improves the work efficiency.

[0074] In an embodiment, the crane boom comprises a controller and a sensor, the controller is electrically connected with the sensor, the pin oil cylinder 9 and the slewing reducer 7 respectively, the controller is used to control the slewing reducer to drive the swing base 5 to switch between the parallel position and the unfolded position; the sensor is arranged in the clamping groove 45 and is used to detect whether the buckle 55 is inserted into the clamping groove 45; when it is detected that the buckle is located in the clamping groove, the controller controls the pin oil cylinder to insert or pull out the pin.

[0075] In this way, when the crane boom needs to be lifted, whether the buckle 55 is inserted into the clamping groove 45 can be detected by the sensor; if the buckle is not inserted into the clamping groove, the sensor sends a first instruction to the controller, the controller receives the first instruction and sends a second instruction to the slewing reducer 7; the slewing reducer receives the second instruction to drive the auxiliary boom 2 to rotate from the parallel position to the unfolded position around the pin shaft 6; after the sensor detects the buckle in the clamping groove, the sensor sends a third instruction to the controller; the controller receives the third instruction and sends a fourth instruction to the pin oil cylinder 9; the pin oil cylinder receives the fourth instruction and drives the telescopic rod to insert into the first insertion hole 45a and the second insertion hole 55a to lock the auxiliary boom 2.

[0076] When the crane boom needs to be folded for transportation, the controller sends a fifth instruction to the pin oil cylinder 9; the pin oil cylinder receives the fifth instruction and drives the telescopic rod to retract, and then the controller sends a sixth instruction to the slewing reducer 7; the slewing reducer receives the sixth instruction and drives the auxiliary boom 2 to rotate from the unfolded position to the parallel position.

[0077] By arranging the sensor and the controller, the switching between the parallel position and the unfolded position of the auxiliary boom 2 and the automatic locking of the auxiliary boom 2 by the pin oil cylinder 9 are automatically realized, and the degree of automation is high.

[0078] Finally, it should be noted that: the above only describes the preferred embodiments of the present application and is not used to limit the present application, although the foregoing embodiments are described in detail, for those skilled in the art, the technical solutions recorded in the foregoing embodiments can be modified or some technical features can be replaced equivalently. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A boom for a work machine, characterized by: It comprises a main arm and a sub-arm; The main arm comprises a main base arm and a main telescopic arm, the main telescopic arm can be retracted into or extended out of the main base arm; The sub-arm is used for hoisting heavy objects, the sub-arm can rotate relative to the main arm, the sub-arm comprises a sub-base arm and a sub-telescopic arm, the sub-telescopic arm can be retracted into or extended out of the sub-base arm; The main telescopic arm comprises a plurality of main joint arms, a main joint arm far away from the main base arm among the adjacent two main joint arms can be extended or retracted to a main joint arm close to the main base arm, and a main joint arm farthest away from the main base arm among the plurality of main joint arms is rotatably connected with the sub-base arm; The sub-arm has a parallel position and an unfolded position along its rotating direction; when the sub-arm is in the parallel position, the main arm and the sub-arm are arranged side by side along a second direction in the projection along a first direction; when the sub-arm is in the unfolded position, the main arm and the sub-arm are arranged in extension along a third direction in the projection along the first direction, the first direction, the second direction and the third direction are perpendicular to each other; The crane arm comprises an ear plate, a swing seat and a pin shaft; one of the ear plate and the swing seat is arranged on the main telescopic arm, the other of the ear plate and the swing seat is arranged on the sub-base arm, the ear plate is formed with a slot and a first pin hole communicating with the slot, the swing seat is formed with an insertion block, the insertion block is formed with a second pin hole, and the insertion block is inserted into the slot; the pin shaft is arranged through the first pin hole and the second pin hole, so that the sub-arm can rotate around the pin shaft.

2. A load arm for a work machine as claimed in claim 1, characterised in that: The crane arm comprises a slewing reducer, the slewing reducer is arranged on the main telescopic arm and is used to drive the sub-arm to rotate around the pin shaft.

3. A load arm for a work machine as set forth in claim 2, characterized in that: A clamping groove is formed on one side of the ear plate away from the slot along the second direction, a clamping buckle is formed on one side of the swing seat away from the insertion block along the second direction, and the clamping groove and the clamping buckle are in clamping cooperation when the sub-arm is in the unfolded position.

4. A load arm for a work machine as set forth in claim 3, characterized in that: The crane arm comprises a pin insertion oil cylinder, the pin insertion oil cylinder is arranged on the ear plate, a slot wall of the clamping groove is formed with a first insertion hole penetrating along the first direction, the clamping buckle is formed with a second insertion hole penetrating along the first direction, and the extension rod of the pin insertion oil cylinder is arranged through the first insertion hole and the second insertion hole in the state that the clamping buckle is located in the clamping groove.

5. A load arm for a metering device as defined in claim 4, wherein: The crane arm comprises a controller and a sensor, the controller is electrically connected with the sensor, the pin insertion oil cylinder and the slewing reducer respectively, the controller is used to control the slewing reducer to drive the swing seat to switch between the parallel position and the unfolded position, and the sensor is arranged in the clamping groove and is used to detect the clamping buckle; when the clamping buckle is detected to be located in the clamping groove, the controller controls the pin insertion oil cylinder to insert or pull out the pin.

6. A load arm for a metering device as defined in claim 4, wherein: A guide groove is formed around the second insertion hole, and the extension rod of the pin insertion oil cylinder is arranged through the second insertion hole through the guide groove.

7. The lift arm for use on a work machine of claim 1, wherein: The crane arm comprises a sub-amplitude change oil cylinder, the sub-amplitude change oil cylinder is supported in the sub-base arm in an extendable and retractable manner.

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