System and method for driving telescopic boom of crane to stretch out and draw back

Abstract

The invention relates to the technical field of hydraulic driving, in particular to a system for driving a telescopic boom of a crane to stretch, which comprises a first boom section, a second boom section and a third boom section, a first driving device is arranged at the bottom of a first insertion cavity, and a second driving device is arranged on the side surface of the top of the second boom section; the first driving device and the second driving device are the same in structure and each comprise a hydraulic cylinder and two piston rods, a circle of limiting ring dividing the hydraulic cylinder into two driving cavities is arranged in the middle of the interior of the hydraulic cylinder along the side wall, and the two piston rods are arranged in the two driving cavities respectively. The two driving devices are arranged, oil is conveyed inwards from the middle of the hydraulic cylinder, the two piston rods extend out of the hydraulic cylinder so as to drive the arm sections connected with the piston rods to extend, and the original structure that one piston rod drives extension is converted into the structure that the two piston rods drive extension; in other words, force borne by one piston rod is shared by the two piston rods during original lifting, the risk that the hydraulic device is damaged is reduced, and the service life of the hydraulic device is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic drive, and particularly relates to a system and method for driving the telescopic boom of a crane to extend and retract. Background Art

[0002] During hoisting, a crane often extends and retracts its robotic arm as needed to improve hoisting flexibility and adaptability. In the prior art, the telescopic boom of a crane is driven by a cylinder or a hydraulic cylinder. Driving the telescopic boom through a hydraulic drive has high power transmission efficiency: the hydraulic system transmits power through hydraulic oil, and can achieve the purpose of adapting to complex working environments, being easy to operate, and being safe and reliable.

[0003] In the prior art, when driving the telescopic boom to extend and retract through a hydraulic cylinder, a hydraulic device with a long piston rod is required for driving. When hoisting heavy objects, the long piston rod is easily damaged. Moreover, when the existing hydraulic device is used to drive the telescopic boom, generally all hydraulic devices are placed outside, and it is easy for dust to accumulate and enter the oil cylinder, which affects the use quality and efficiency of the hydraulic device, and also reduces the service life of the hydraulic device. Summary of the Invention

[0004] The present invention provides a system and method for driving the telescopic boom of a crane to extend and retract, so as to drive the telescopic boom to extend and retract through a hydraulic device with two piston rods, so as to reduce the force on each piston rod and avoid the piston rod breaking or the hydraulic device being damaged during hoisting.

[0005] To achieve the above object, the technical solution of the present invention is: to provide a system for driving the telescopic boom of a crane to extend and retract, including a first boom section, a second boom section, and a third boom section. A first insertion cavity and a second insertion cavity are respectively arranged inside the first boom section and the second boom section, and the second boom section and the third boom section are respectively slidably inserted into the first insertion cavity and the second insertion cavity; the innovation lies in: a first driving device is arranged at the bottom of the first insertion cavity, and a second driving device is arranged on the side surface of the top of the second boom section;

[0006] The first driving device and the second driving device have the same structure, and both include a hydraulic cylinder and two piston rods. A limiting ring is arranged along the side wall in the middle of the hydraulic cylinder, and the limiting ring divides the hydraulic cylinder into two driving cavities. The two piston rods are respectively arranged in the two driving cavities, and the driving ends respectively penetrate through the bottom and the top of the hydraulic cylinder; the driving ends of the piston rods below the first driving device and the second driving device are respectively connected to the bottom inside the first insertion cavity and the second boom section, and the driving ends of the piston rods above the first driving device and the second driving device are respectively connected to the bottom of the first boom section and the top of the third boom section; the hydraulic cylinders of the first driving device and the second driving device are respectively slidably connected to the first boom section and the second boom section;

[0007] The first driving device drives the second arm section and its third arm section to telescopically move in the first insertion cavity, and the second driving device drives the third arm section to telescopically move in the second insertion cavity.

[0008] Further, it further includes six oil delivery hoses. Each hydraulic cylinder is provided with three oil inlet ports communicating with the hydraulic cylinder. One of the oil inlet ports is arranged on the limit ring of the hydraulic cylinder, and the other two oil inlet ports are respectively arranged on the side surfaces of the two driving cavities of the hydraulic cylinder away from each other. The six oil delivery hoses are respectively connected to the six oil inlet ports; on the side surface of the first arm section corresponding to the first driving device, an operation door is detachably provided. The operation door is provided with an oil delivery channel, and the three oil delivery hoses corresponding to the first driving device are connected to the corresponding oil inlet ports through the oil delivery channel; the oil inlet port on the second driving device is located on the side surface away from the second arm section;

[0009] At the position where each driving cavity is provided with an oil inlet port, a limit block is further provided. The limit block is arranged on the side of the oil inlet port close to the limit ring.

[0010] Further, the structure of the detachable connection between the operation door and the first arm section is: the outer end of the operation door extends outwards in all directions to form a connecting plate, and the first arm section is provided with a connecting groove corresponding to the connecting plate. When the operation door is closed, the connecting plate is placed in the connecting groove and is connected to the first arm section through bolts passing through the connecting plate.

[0011] Further, the two piston rods on the first driving device and the second driving device respectively penetrate through the top end and the bottom end of the corresponding hydraulic cylinder. Two annular sealing grooves are respectively arranged inside the top end and the bottom end of the hydraulic cylinder. Each of the annular sealing grooves is provided with a sealing ring, and the sealing ring is tightly sleeved on the corresponding piston rod in a close-fitting manner; on the outer end of each sealing ring away from the piston rod, several sealing springs are evenly connected along the circumference, and the sealing springs are fixed in the annular sealing groove.

[0012] Further, the horizontal cross-section of the sealing ring is in an M shape, and the part of the M-shaped sealing ring with three ends is the inner end. The inner end of the sealing ring is in close contact with the piston rod, and the outer end is connected to the sealing spring.

[0013] Further, on the driving end of the piston rod of the first driving device located below, a first lower top plate is provided. The first lower top plate is fixed to the bottom inside the first insertion cavity through bolts; on the driving end of the piston rod of the first driving device located above, a first upper top plate is provided. The first upper top plate is fixed to the bottom end of the second arm section through bolts; a clamping groove is further provided at the center of the bottom end of the second arm section, and the driving end of the piston rod of the first driving device located above extends upwards and is placed in the clamping groove.

[0014] Further, the structure of the hydraulic cylinder of the first driving device slidingly connected to the first arm section is as follows: Two slide bars are respectively arranged on opposite sides of the hydraulic cylinder. Two sliding assemblies are respectively arranged in the first insertion cavity corresponding to the two slide bars. The sliding assembly includes two parallel sliders, and a chute for inserting the slide bar is formed between the two sliders. The hydraulic cylinder is slidingly connected to the first arm section by sliding the slide bar in the chute.

[0015] Further, a receiving port is provided at the top of the first arm section corresponding to the second driving device, and the second driving device is placed in the receiving port; a second lower top plate is provided at the driving end of the piston rod located below the second driving device, and a fixing plate extends outward corresponding to the second lower top plate on the second arm section. When the second arm section is not extended, the fixing plate is placed at the bottom of the receiving port; the second lower top plate and the fixing plate are bolted and fixed; a second upper top plate is provided at the driving end of the piston rod located above the second driving device close to the side of the third arm section. A reverse L-shaped connecting member is further included. The vertical end of the connecting member is connected to the upper end of the third arm section, and a fixing groove is provided corresponding to the second upper top plate at the horizontal end. The second upper top plate is placed in the fixing groove and fixed to the connecting member by bolts.

[0016] Further, the structure of the second driving device slidingly connected to the second arm section is as follows: A rod groove is provided inward corresponding to the second driving device on the outer side of the top of the second arm section. A slide rod is arranged along the axial direction of the second arm section in the rod groove. A sliding sleeve is provided corresponding to the slide rod on the outer side of the lower part of the hydraulic cylinder. The hydraulic cylinder is slidingly connected to the second arm section by slidingly sleeving the sliding sleeve on the slide rod.

[0017] To achieve the above object, the present invention further provides a method for driving the telescopic boom of a crane to extend and retract. The innovation lies in that: The method is realized through a system for driving the telescopic boom of a crane to extend and retract. The specific steps are as follows:

[0018] S1. Extension preparation: The second arm section is placed in the first insertion cavity, the third arm section is placed in the first insertion cavity, the two piston rods of the first driving device and the second driving device are both located at the limit ring. Connect the oil delivery hose to the corresponding oil inlet pipe opening. The first lower top plate is fixed at the bottom of the first insertion cavity. The first upper top plate is fixed to the bottom of the second arm section. Close and fix the operation door; Fix the second lower top plate and the fixing plate, and fix the second upper top plate and the connecting member;

[0019] S2. Elongation of the second arm section: In the hydraulic cylinder of the first driving device, oil is pumped into the oil delivery hose connected to the connecting limit ring. Through the oil delivery hose, oil enters the space enclosed by the corresponding limit ring. The oil entering pushes the two piston rods towards both ends. The piston rod located above pushes the second arm section to slide upward and extend in the first insertion cavity. At the same time, since the end of the piston rod located below is fixed, the oil entering causes the hydraulic cylinder to slide upward, further driving the second arm section to slide upward and extend until the two piston rods respectively move to the limit blocks at the upper and lower ends of the hydraulic cylinder due to the oil entering; the elongation of the second arm section drives the third arm section and the second driving device to move upward as a whole;

[0020] S3. Elongation of the third arm section: In the hydraulic cylinder of the second driving device, oil is pumped into the oil delivery hose connected to the connecting limit ring. Through the oil delivery hose, oil enters the space enclosed by the corresponding limit ring. The oil entering pushes the two piston rods towards both ends. The piston rod located above drives the third arm section to slide upward and extend in the second insertion cavity through the connecting piece. At the same time, since the end of the piston rod located below is fixed, the oil entering causes the hydraulic cylinder to slide upward, further driving the third arm section to slide upward and extend until the two piston rods respectively move to the limit blocks at the upper and lower ends of the hydraulic cylinder due to the oil entering;

[0021] S4. Retraction of the telescopic arm: When it is necessary to retract the telescopic arm, oil is pumped into the driving cavities of the two hydraulic cylinders through the oil delivery hoses located at both ends successively or simultaneously, so that the two piston rods discharge the oil between them, move the piston rod located above down to the limit ring, and at the same time move the hydraulic cylinder down until the limit ring contacts the piston rod below, thereby retracting the third arm section into the second insertion cavity and retracting the second arm section into the first insertion cavity, completing the retraction process of the telescopic arm.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] A system for driving the telescopic arm of a crane according to the present invention is provided with two driving devices. When in use, by pumping oil inward from the middle of the hydraulic cylinder, the two piston rods are extended out of the hydraulic cylinder to drive the arm section of the crane connected to the piston rod to elongate. By converting the original structure of driving elongation by one piston rod into driving elongation by two piston rods, that is, sharing the force originally borne by one piston rod during lifting by two piston rods, the risk of damage to the hydraulic device is reduced and its service life is improved.

[0024] A method for driving the telescopic arm of a crane according to the present invention describes the process of operating the system for driving the telescopic arm of the crane. While ensuring the telescopic arm can be driven to perform lifting, the telescopic efficiency is improved and the risk of damage to the driving device is reduced. Description of the Drawings

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings required for the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments recorded in the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0026] Figure 1 It is a cross-sectional view of a system for driving the telescopic boom of a crane according to the present invention.

[0027] Figure 2 For the present invention Figure 1 Schematic structural diagram of the first driving device in

[0028] Figure 3 For the present invention Figure 2 Enlarged view at A in

[0029] Figure 4 It is a cross-sectional view of the seal ring and seal spring of the present invention placed in the annular seal groove.

[0030] Figure 5 It is a perspective view of the sliding connection structure between the first driving device and the first boom section of the present invention.

[0031] Figure 6 For the present invention Figure 1 Schematic structural diagram of the second driving device in

[0032] Figure 7 For the present invention Figure 1 Schematic structural diagram of the first driving device driving the second boom section to extend in

[0033] Figure 8 For the present invention Figure 7 Schematic structural diagram of the second driving device driving the third boom section to extend in

[0034] Figure 9 It is a flowchart of a method for driving the telescopic boom of a crane according to the present invention.

[0035] Among them, 1. the first arm section; 2. the second arm section; 3. the third arm section; 4. the first insertion cavity; 5. the second insertion cavity; 6. the first driving device; 7. the second driving device; 8. the hydraulic cylinder; 9. the piston rod; 10. the limit ring; 11. the driving cavity; 12. the oil delivery hose; 13. the oil inlet pipe opening; 14. the operation door; 15. the oil delivery channel; 16. the limit block; 17. the connecting plate; 18. the connecting groove; 19. the annular sealing groove; 21. the sealing ring; 22. the sealing spring; 23. the first lower top plate; 25. the first upper top plate; 26. the clamping groove; 27. the sliding strip; 28. the sliding block; 29. the sliding groove; 30. the accommodating opening; 31. the second lower top plate; 32. the fixing plate; 33. the second upper top plate; 34. the connecting member; 35. the fixing groove; 36. the rod groove; 37. the sliding rod; 38. the sliding sleeve. Detailed implementation manners

[0036] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0037] In this embodiment, the orientation words "top end", "top", "above", "below", "bottom" and "bottom end" are respectively equivalent to "tilted top end", "tilted top", "tilted above", "tilted below", "tilted bottom" and "tilted bottom end" on the basis of the telescopic arm of the present invention being tilted.

[0038] Embodiment 1

[0039] This embodiment provides a system for driving the telescopic movement of the telescopic arm of a crane, including a first arm section 1, a second arm section 2 and a third arm section 3. A first insertion cavity 4 and a second insertion cavity 5 are respectively provided in the first arm section 1 and the second arm section 2. The second arm section 2 and the third arm section 3 are respectively slidably inserted into the first insertion cavity 4 and the second insertion cavity 5. Its specific structure is as Figure 1 、 2 shown in and 6. A first driving device 6 is provided at the bottom of the first insertion cavity 4, and a second driving device 7 is provided on the side of the top of the second arm section 2.

[0040] The first driving device 6 and the second driving device 7 have the same structure, and both include a hydraulic cylinder 8 and two piston rods 9. In the middle of the hydraulic cylinder 8, a limiting ring 10 is provided along the side wall. The limiting ring 10 divides the hydraulic cylinder 8 into two driving chambers 11. The two piston rods 9 are respectively arranged in the two driving chambers 11, and the driving ends respectively penetrate through the bottom and the top of the hydraulic cylinder 8. The driving ends of the piston rods 9 below the first driving device 6 and the second driving device 7 are respectively connected to the inner bottom of the first insertion cavity 4 and the second arm section 2. The driving ends of the piston rods 9 above the first driving device 6 and the second driving device 7 are respectively connected to the bottom of the first arm section 1 and the top of the third arm section 3. The hydraulic cylinders 8 of the first driving device 6 and the second driving device 7 are respectively slidably connected to the first arm section 1 and the second arm section 2. The piston rod 9 is in a T shape, the horizontal part is located inside the hydraulic cylinder 8, and the vertical part penetrates through the hydraulic cylinder and is connected to the structure to be driven outward. The driving end in this embodiment refers to the vertical end of the piston rod 9, that is, the end connected to the structure to be driven.

[0041] The first driving device 6 drives the second arm section 2 and its third arm section 3 to expand and contract in the first insertion cavity 4, and the second driving device 7 drives the third arm section 3 to expand and contract in the second insertion cavity 5.

[0042] In this embodiment, by providing the first driving device 6 and the second driving device 7, when in use, the two piston rods 9 extend out of the hydraulic cylinder 8, and the arm sections of the crane connected to the piston rods 9 can be driven to extend. By converting the structure of driving the extension by one original piston rod 9 into driving the extension by two piston rods 9, that is, when extending the telescopic arm, the force originally borne by one piston rod 9 during lifting is shared by the two piston rods 9, reducing the risk of damage to the hydraulic device due to the overlong piston rod 9 and improving its service life.

[0043] Embodiment 2

[0044] Based on the above embodiment, this embodiment further includes six oil delivery hoses 12. Each hydraulic cylinder 8 is provided with three oil inlet ports 13 communicated with the hydraulic cylinder 8. One of the oil inlet ports 13 is arranged on the limiting ring 10 of the hydraulic cylinder 8, and the other two oil inlet ports 13 are respectively arranged on the side surfaces of the two driving chambers 11 of the hydraulic cylinder 8 away from each other. The six oil delivery hoses 12 are respectively connected to the six oil inlet ports 13. A service door 14 is detachably arranged on the side surface of the first arm section 1 corresponding to the first driving device 6. An oil delivery channel 15 is arranged on the service door 14. The three oil delivery hoses 12 corresponding to the first driving device 6 are connected to the corresponding oil inlet ports 13 through the oil delivery channel 15. The oil inlet ports 13 on the second driving device 7 are located on the side surface away from the second arm section 2.

[0045] At the position where the oil inlet port 13 is arranged in each driving chamber 11, a limiting block 16 is also arranged. The limiting block 16 is arranged on the side of the oil inlet port 13 close to the limiting ring 10.

[0046] In this embodiment, when the telescopic arm needs to be extended, oil is transported through the oil delivery hose 12 into the oil inlet pipe opening 13 located on the limit ring 10, driving the piston rod 9 to move in a direction away from each other. That is, the piston rod 9 located above extends upward (eventually reaching the limit block 16 located above), driving the telescopic arm part connected to it to extend. Since the piston rod 9 located below is fixed, the oil inlet in the hydraulic cylinder 8 drives the hydraulic cylinder 8 to move upward relative to the piston rod 9 below until the piston rod 9 below reaches the limit block 16. Further driving the telescopic arm part connected to the piston rod 9 above to extend.

[0047] The arrangement of the oil delivery hose 12 in this embodiment enables the oil delivery hose 12 to move with the first driving device 6 or the second driving device 7 during use.

[0048] Embodiment 3

[0049] Based on the above embodiment, the detachable connection structure between the operation door 14 and the first arm section 1 in this embodiment is as Figure 2 shown. The outer end of the operation door 14 extends outwards in all directions to form a connecting plate 17. A connecting groove 18 is provided on the side surface of the first arm section 1 corresponding to the connecting plate 17. When the operation door 14 is closed, the connecting plate 17 is placed in the connecting groove 18 and is connected to the first arm section 1 through bolts penetrating the connecting plate 17.

[0050] The detachable connection between the operation door 14 and the first arm section 1 in this embodiment facilitates the maintenance of the first driving device 6 and also facilitates the connection of the oil delivery hose 12 and the oil inlet hose.

[0051] Embodiment 4

[0052] Based on the above embodiment, the two piston rods 9 on the first driving device 6 and the second driving device 7 in this embodiment respectively penetrate through the top and bottom ends of the corresponding hydraulic cylinders 8. Two annular sealing grooves 19 are respectively provided inside the top and bottom ends of the hydraulic cylinder 8, as Figure 3 and 4 shown. A sealing ring 21 is provided in each annular sealing groove 19. The sealing ring 21 is tightly sleeved on the corresponding piston rod 9; several sealing springs 22 are evenly connected along the circumference at the outer end of each sealing ring 21 away from the piston rod 9, and the sealing springs 22 are fixed in the annular sealing groove 19.

[0053] In this embodiment, the sealing ring 21 and the sealing spring 22 provided in the sealing groove are used to fit and seal the piston rod 9 (the sealing ring 21 is elastic). Through the setting of the sealing spring 22, the sealing ring 21 can always be tightly attached to the piston rod 9. Even if the sealing ring 21 is worn due to use, it will be pressed inward by the elastic force of the sealing spring 22 to fit the piston rod 9, ensuring the sealing performance inside the hydraulic cylinder 8. At the same time, it can also extend the service life of the sealing ring 21, with flexible use and good sealing effect.

[0054] Example 5

[0055] Based on the above embodiments, the horizontal cross-section of the sealing ring 21 in this embodiment is in an M shape, as Figure 3 shown, and the part of the M-shaped sealing ring 21 with three ends is the inner end. The inner end of the sealing ring 21 is attached to the piston rod 9, and the outer end is connected to the sealing spring 22.

[0056] In this embodiment, the sealing ring 21 is set in an M shape, and the side with three ends is attached to the piston rod 9. It can be connected to the piston rod 9 through multiple parts at the end, increasing the comprehensiveness of sealing. Even if one of the ends is worn due to the piston rod 9, it can still be sealed by other ends fitting, providing multi-dimensional sealing for the piston rod 9. Coupled with the elastic force of the sealing spring 22, the sealing effect of the sealing ring 21 is further improved.

[0057] Example 6

[0058] Based on the above embodiments, a first lower top plate 23 is provided at the driving end of the piston rod 9 below the first driving device 6 in this embodiment. The first lower top plate 23 is fixed to the inner bottom of the first insertion cavity 4 by bolts; a first upper top plate 25 is provided at the driving end of the piston rod 9 above the first driving device 6. The first upper top plate 25 is fixed to the bottom end of the second arm section 2 by bolts; a clamping groove 26 is further provided at the center of the bottom end of the second arm section 2. The driving end of the piston rod 9 above the first driving device 6 extends upward and is placed in the clamping groove 26.

[0059] In this embodiment, the piston rod 9 below the first driving device 6 is fixed to the inner bottom of the first insertion cavity 4 through the first lower top plate 23, and the piston rod 9 above is fixed to the bottom of the second arm section 2 through the first upper top plate 25. Driven by the first driving device 6, the second arm section 2 is driven to extend upward in the way of driving the piston rod 9 to extend out of the hydraulic cylinder 8. When retracting, only need to feed oil into both ends of the hydraulic cylinder 8 through the oil delivery hose 12 respectively, and move the two piston rods 9 to the limiting ring 10 to complete the retraction of the second arm section 2.

[0060] Example 7

[0061] Based on the above embodiments, the structure of the hydraulic cylinder 8 of the first driving device 6 slidingly connected to the first arm section 1 in this embodiment is as Figure 5 shown. Two slide bars 27 are respectively provided on the opposite sides of the hydraulic cylinder 8. Two sliding components are respectively provided in the first insertion cavity 4 corresponding to the two slide bars 27. The sliding component includes two parallel sliders 28. A sliding groove 29 for inserting the slide bar 27 is formed between the two sliders 28. The hydraulic cylinder 8 is slidingly connected to the first arm section 1 by sliding the slide bar 27 in the sliding groove 29.

[0062] The hydraulic cylinder 8 of the first driving device 6 is slidably connected to the first arm section 1, which can ensure that on the basis that the piston rod 9 below is fixed, when oil is fed into the middle of the hydraulic cylinder 8, the hydraulic cylinder 8 can tilt and move upward until the piston rod 9 below is located at the lower limit block 16, that is, the piston rod 9 below is indirectly extended in the way of the upward sliding of the hydraulic cylinder 8 to achieve the purpose of further extending the second arm section 2.

[0063] Embodiment 8

[0064] Based on the above embodiment, a receiving port 30 is provided corresponding to the second driving device 7 at the top of the first arm section 1 in this embodiment, and the second driving device 7 is placed in the receiving port 30. As Figure 6 shown, a second lower top plate 31 is provided at the driving end of the piston rod 9 below the second driving device 7, and a fixing plate 32 extends outward from the second arm section 2 corresponding to the second lower top plate 31. When the second arm section 2 is not extended, the fixing plate 32 is placed at the bottom of the receiving port 30; the second lower top plate 31 and the fixing plate 32 are bolt-fixed; a second upper top plate 33 is provided at the driving end of the piston rod 9 above the second driving device 7 close to the side of the third arm section 3. A reverse L-shaped connecting member 34 is further included. The vertical end of the connecting member 34 is connected to the upper end of the third arm section 3, and a fixing groove 35 is provided on the horizontal end corresponding to the second upper top plate 33. The second upper top plate 33 is placed in the fixing groove 35 and fixed to the connecting member 34 by bolts.

[0065] In this embodiment, the second driving device 7 is placed at the receiving port 30. Similarly, the piston rod 9 below is fixed to the second arm section 2, and the hydraulic cylinder 8 is slidably connected to the second arm section 2. Its driving method is the same as that of the first driving device 6. By extending the piston rod 9 above out of the hydraulic cylinder 8 and the way that the hydraulic cylinder 8 moves upward relative to the first piston rod 9, the purpose of driving the third arm section 3 to extend is achieved. It is convenient and efficient to use, and the risk of damage to the hydraulic device during lifting is small.

[0066] Embodiment 9

[0067] Based on the above embodiment, the structure of the second driving device 7 slidably connected to the second arm section 2 in this embodiment is as follows: a rod groove 36 is provided inward corresponding to the second driving device 7 on the outer side of the top of the second arm section 2. A sliding rod 37 is provided in the rod groove 36 along the axial direction of the second arm section 2. A sliding sleeve 38 is provided on the outer side of the lower part of the hydraulic cylinder 8 corresponding to the sliding rod 37. The hydraulic cylinder 8 is slidably sleeved on the sliding rod 37 through the sliding sleeve 38 and is slidably connected to the second arm section 2.

[0068] The specific structure of the hydraulic cylinder 8 of the second driving device 7 slidably connected to the second arm section 2 in this embodiment facilitates the upward movement of the hydraulic cylinder 8 of the second driving device 7 relative to the piston rod 9 below to drive the third arm section 3 to extend.

[0069] Embodiment 10

[0070] This embodiment provides a method for driving the telescopic boom of a crane. This method is implemented through the above-mentioned system for driving the telescopic boom of a crane, and the specific steps are as follows: Figure 9 as shown:

[0071] S1. Elongation preparation: The second boom section 2 is placed in the first insertion cavity 4, the third boom section 3 is placed in the first insertion cavity 4, the two piston rods 9 of the first driving device 6 and the second driving device 7 are both located at the limit ring 10, the oil delivery hose 12 is connected to the corresponding oil inlet pipe opening 13, the first lower top plate 23 is fixed at the inner bottom of the first insertion cavity 4, the first upper top plate 25 is fixed to the bottom of the second boom section 2, and the operation door 14 is closed and fixed; the second lower top plate 31 and the fixing plate 32 are fixed, and the second upper top plate 33 and the connecting member 34 are fixed;

[0072] S2. Elongation of the second boom section 2: In the hydraulic cylinder 8 of the first driving device 6, oil is delivered into the oil delivery hose 12 connected to the limit ring 10, and oil is introduced into the space enclosed by the corresponding limit ring 10 through the oil delivery hose 12. The oil pushes the two piston rods 9 towards both ends. The piston rod 9 located above pushes the second boom section 2 to slide upward in the first insertion cavity 4. At the same time, since the end of the piston rod 9 located below is fixed, the oil inlet causes the hydraulic cylinder 8 to slide upward, further driving the second boom section 2 to slide upward until the two piston rods 9 respectively move to the limit blocks 16 at the upper and lower ends in the hydraulic cylinder 8 due to the oil inlet; the elongation of the second boom section 2 drives the third boom section 3 and the second driving device 7 to move upward as a whole. The structure after the upward movement is as follows: Figure 7 as shown.

[0073] S3. Elongation of the third boom section 3: In the hydraulic cylinder 8 of the second driving device 7, oil is delivered into the oil delivery hose 12 connected to the limit ring 10, and oil is introduced into the space enclosed by the corresponding limit ring 10 through the oil delivery hose 12. The oil pushes the two piston rods 9 towards both ends. The piston rod 9 located above drives the third boom section 3 to slide upward in the second insertion cavity 5 through the connecting member 34. At the same time, since the end of the piston rod 9 located below is fixed, the oil inlet causes the hydraulic cylinder 8 to slide upward, further driving the third boom section 3 to slide upward until the two piston rods 9 respectively move to the limit blocks 16 at the upper and lower ends in the hydraulic cylinder 8 due to the oil inlet. The structure after the movement is as follows: Figure 8 as shown.

[0074] S4. Retraction of the telescopic boom: When it is necessary to retract the telescopic boom, oil is introduced into the driving chambers 11 in the two hydraulic cylinders 8 through the oil delivery hoses 12 located at both ends successively or simultaneously, so that the two piston rods 9 discharge the oil between them through the corresponding oil delivery hoses 12, move the piston rod 9 located above down to the limit ring 10, and at the same time cause the hydraulic cylinder 8 to move down until the limit ring 10 contacts the piston rod 9 below, thereby retracting the third boom section 3 into the second insertion cavity 5 and the second boom section 2 into the first insertion cavity 4, completing the retraction process of the telescopic boom.

[0075] In the present embodiment, when retracting in sequence, the two piston rods 9 of the second driving device 7 or the first driving device 6 can be first retracted to the limiting ring 10 in the hydraulic cylinder 8, that is, the third arm section 3 or the second arm section 2 is retracted, and then the second arm section 2 or the third arm section 3 is retracted by the first driving device 6 or the second driving device 7.

[0076] The above-described embodiments are only descriptions of the preferred embodiments of the present invention, and do not limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made by ordinary engineering and technical personnel in the art to the technical solutions of the present invention should fall within the protection scope of the present invention. The technical content for which the present invention requests protection has been fully recorded in the claims.

Claims

1. A system for driving a telescopic boom of a crane to extend and retract, comprising a first boom section, a second boom section and a third boom section, wherein a first insertion cavity and a second insertion cavity are respectively provided in the first boom section and the second boom section, and the second boom section and the third boom section are respectively slidably inserted in the first insertion cavity and the second insertion cavity; characterized in that: A first driving device is provided at the bottom of the first insertion cavity, and a second driving device is provided on the top side of the second arm section; The first drive device and the second drive device have the same structure, both of which include a hydraulic cylinder and two piston rods. A circle of limiting rings is provided along the side wall in the middle of the hydraulic cylinder. The limiting ring divides the hydraulic cylinder into two driving chambers. The two piston rods are respectively provided in the two driving chambers, and the driving ends respectively penetrate the bottom and top of the hydraulic cylinder; the driving ends of the piston rods below the first drive device and the second drive device are respectively connected to the bottom of the first insertion chamber and the second arm section, and the driving ends of the piston rods above the first drive device and the second drive device are respectively connected to the bottom of the first arm section and the top of the third arm section; the hydraulic cylinders of the first drive device and the second drive device are respectively slidably connected to the first arm section and the second arm section; The first driving device drives the second arm section and the third arm section to extend and retract in the first insertion cavity, and the second driving device drives the third arm section to extend and retract in the second insertion cavity.

2. The system for driving the telescopic arm of a crane to extend and retract according to claim 1, characterized in that: It also includes six oil delivery hoses, each hydraulic cylinder is provided with three oil inlet ports connected to the hydraulic cylinder, one of the oil inlet ports is provided on the limit ring of the hydraulic cylinder, and the other two oil inlet ports are respectively provided on the side of the ends of the two driving chambers of the hydraulic cylinder that are away from each other, and the six oil delivery hoses are respectively connected to the six oil inlet ports; the first arm section is provided with a detachable operating door on the side corresponding to the first driving device, and the operating door is provided with an oil delivery channel, and the three oil delivery hoses corresponding to the first driving device are connected to the corresponding oil inlet ports through the oil delivery channel; the oil inlet port on the second driving device is located on the side away from the second arm section; A limiting block is also provided at the position where the oil inlet is provided in each driving cavity, and the limiting block is provided on one side of the oil inlet close to the limiting ring.

3. The system for driving the telescopic arm of a crane to extend and retract according to claim 2, characterized in that: The structure of the detachable connection between the operating door and the first arm section is as follows: a connecting plate extends outwardly from the outer end of the operating door, and a connecting groove is provided on the side of the first arm section corresponding to the connecting plate. When the operating door is closed, the connecting plate is placed in the connecting groove and is connected to the first arm section by bolts penetrating the connecting plate.

4. The system for driving the telescopic arm of a crane to extend and retract according to claim 2, characterized in that: The two piston rods on the first drive device and the second drive device are respectively arranged through the top and bottom ends of the corresponding hydraulic cylinders. Two annular sealing grooves are respectively arranged in the top and bottom ends of the hydraulic cylinders. A sealing ring is arranged in each of the annular sealing grooves. The sealing ring is tightly fitted on the corresponding piston rod. The outer end of each sealing ring away from the piston rod is also evenly connected with several sealing springs along the circumference. The sealing springs are fixed in the annular sealing groove.

5. The system for driving the telescopic arm of a crane to extend and retract according to claim 4, characterized in that: The horizontal cross section of the sealing ring is M-shaped, and the portion of the M-shaped sealing ring with three ends is the inner end, the inner end of the sealing ring is arranged in contact with the piston rod, and the outer end is connected to the sealing spring.

6. The system for driving the telescopic arm of a crane to extend and retract according to claim 1, characterized in that: The driving end of the piston rod of the first driving device located at the bottom is provided with a first lower top plate, and the first lower top plate is fixed to the bottom of the first insertion cavity by bolts; the driving end of the piston rod of the first driving device located at the top is provided with a first upper top plate, and the first upper top plate is fixed to the bottom end of the second arm section by bolts; a slot is also provided at the center of the bottom end of the second arm section, and the driving end of the piston rod of the first driving device located at the top extends upward and is placed in the slot.

7. The system for driving the telescopic arm of a crane to extend and retract according to claim 6, characterized in that: The structure of the sliding connection between the hydraulic cylinder and the first arm section of the first driving device is as follows: two sliding bars are respectively provided on the opposite sides of the hydraulic cylinder, and two sliding components are respectively provided in the first insertion cavity corresponding to the two sliding bars. The sliding component includes two parallel sliders, and a sliding groove is formed between the two sliders for inserting the sliding bar. The hydraulic cylinder slides in the sliding groove through the sliding bar and is slidingly connected to the first arm section.

8. The system for driving the telescopic arm of a crane to extend and retract according to claim 1, characterized in that: A accommodating opening is provided at the top of the first arm section corresponding to the second driving device, and the second driving device is placed in the accommodating opening; a second lower top plate is provided at the driving end of the piston rod of the second driving device located below, and a fixing plate extends outward from the second arm section corresponding to the second lower top plate, and when the second arm section is not extended, the fixing plate is placed at the bottom of the accommodating opening; the second lower top plate and the fixing plate are fixed by bolts; a second upper top plate is provided at the side of the driving end of the piston rod of the second driving device located above, close to the third arm section, and also includes an inverted L-shaped connecting piece, the vertical end of the connecting piece is connected to the upper end of the third arm section, and the horizontal end is provided with a fixing groove corresponding to the second upper top plate, the second upper top plate is placed in the fixing groove, and is fixed by bolts and the connecting piece.

9. The system for driving the telescopic arm of a crane to extend and retract according to claim 8, characterized in that: The structure of the sliding connection between the second driving device and the second arm section is as follows: a rod groove is provided inwardly on the outer side of the top of the second arm section corresponding to the second driving device, a sliding rod is provided in the rod groove along the axial direction of the second arm section, a sliding sleeve is provided on the outer side of the lower part of the hydraulic cylinder corresponding to the sliding rod, and the hydraulic cylinder is slidingly connected to the sliding rod through the sliding sleeve.

10. A method for driving a crane telescopic arm to extend and retract, characterized in that: The method is implemented by a system that drives the telescopic arm of the crane to extend and retract, and the specific steps are: S1. Preparation for extension: The second arm section is placed in the first insertion cavity, the third arm section is placed in the first insertion cavity, the two piston rods of the first drive device and the second drive device are both located at the limit ring, the oil delivery hose is connected to the corresponding oil inlet port, the first lower top plate is fixed to the bottom of the first insertion cavity, the first upper top plate is fixed to the bottom of the second arm section, the operating door is closed and fixed; the second lower top plate is fixed to the fixing plate, and the second upper top plate is fixed to the connecting piece; S2. The second arm section extends: oil is delivered from the hydraulic cylinder of the first drive device to the oil delivery hose connected to the limit ring, and oil is delivered to the space surrounded by the corresponding limit ring through the oil delivery hose. The delivered oil pushes the two piston rods to the two ends, and the piston rod located at the top pushes the second arm section to slide upward in the first insertion cavity and extend. At the same time, since the end of the piston rod located at the bottom is fixed, the delivered oil causes the hydraulic cylinder to slide upward, further driving the second arm section to slide upward and extend, until the two piston rods are moved to the limit blocks at the upper and lower ends of the hydraulic cylinder respectively due to the delivered oil; the extension of the second arm section drives the third arm section and the second drive device to move upward as a whole; S3. The third boom section extends: oil is delivered from the hydraulic cylinder of the second driving device to the oil delivery hose connected to the limit ring, and oil is delivered to the space surrounded by the corresponding limit ring through the oil delivery hose. The delivered oil pushes the two piston rods to the two ends, and the piston rod located at the top drives the third boom section to slide upward in the second insertion cavity through the connecting piece. At the same time, since the end of the piston rod located at the bottom is fixed, the delivered oil causes the hydraulic cylinder to slide upward, further driving the third boom section to slide upward and extend, until the two piston rods are moved to the limit blocks at the upper and lower ends of the hydraulic cylinder respectively due to the delivered oil. S4. Telescopic arm retraction: When the telescopic arm needs to be retracted, oil is supplied to the driving chambers in the two hydraulic cylinders through the oil delivery hoses at both ends in sequence or simultaneously, so that the two piston rods discharge the oil between them, and the piston rod located above is moved down to the limit ring. At the same time, the hydraulic cylinder is moved down until the limit ring contacts the piston rod below, and then the third arm section is retracted into the second insertion chamber, and the second arm section is retracted into the first insertion chamber, completing the retraction process of the telescopic arm.

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