Telescopic boom frame and crane

Abstract

The invention provides a telescopic boom frame and a crane, the telescopic boom frame comprises a first section of boom, a second section of boom... an Nth section of boom which are sequentially sleeved from outside to inside, and N is greater than or equal to 3; one of a first piston rod and a first cylinder barrel of the first oil cylinder is connected with the first knuckle arm, and the other one of the first piston rod and the first cylinder barrel is connected with the second knuckle arm; one of a second piston rod and a second cylinder barrel of the second oil cylinder is connected with the second section arm, and the other one of the second piston rod and the second cylinder barrel is connected with the third section arm; one of an (N-1) th piston rod and an (N-1) th cylinder barrel of the (N-1) th oil cylinder is connected with the (N-1) th section of arm, and the other one of the (N-1) th piston rod and the (N-1) th cylinder barrel is connected with the Nth section of arm; the arrangement positions of the first oil cylinder, the second oil cylinder... the (N-1) th oil cylinder are mutually independent and do not interfere with each other in telescopic movement. In this way, the use of a rope row is omitted, and the shock resistance of the telescopic boom frame is enhanced; all the oil cylinders do not need to stretch out and draw back in sequence, and then all the knuckle arms are driven to stretch out and draw back freely and independently, so that the crane has higher working efficiency.

Description

Technical Field

[0001] The present application relates to the technical field of lifting equipment, and in particular to a telescopic boom, and also to a crane including the telescopic boom. Background Art

[0002] The main construction condition of the existing telescopic boom crawler crane is hoisting, which is difficult to expand to complex construction conditions such as vibration and impact construction. Since the telescopic structure of the current telescopic boom frame is mainly composed of a cylinder and a rope row, the telescopic boom frame has poor rigidity and poor impact resistance, which limits the applicable construction conditions of the telescopic boom crawler crane. In addition, the multi-section arms of the telescopic boom frame can only be telescopically moved synchronously, and the degree of freedom of telescopic movement of each section arm is poor. Summary of the invention

[0003] In view of this, the purpose of the present application is to provide a telescopic boom and a crane, which solve the problem that the telescopic boom has poor rigidity and that the multi-section boom can only telescope and move synchronously.

[0004] In order to achieve the above objectives, this application provides the following technical solutions:

[0005] A telescopic boom frame, comprising a first boom section, a second boom section, ... an Nth boom section, which are sequentially sleeved from the outside to the inside, N ≥ 3; the telescopic boom frame also includes:

[0006] A first oil cylinder, at least part of which along its axial direction is located inside the Nth section arm, and one of its first piston rod and first cylinder barrel is connected to the first section arm, and the other is connected to the second section arm;

[0007] A second oil cylinder, at least part of which along its axial direction is located inside the Nth section arm, and one of its second piston rod and second cylinder barrel is connected to the second section arm, and the other is connected to the third section arm;

[0008] …

[0009] The N-1 oil cylinder is located inside the N-1 arm along at least a portion of its axial direction, and one of its N-1 piston rod and its N-1 cylinder barrel is connected to the N-1 arm, and the other is connected to the N-1 arm;

[0010] Among them, the first oil cylinder, the second oil cylinder ... the N-1th oil cylinder are arranged at positions independently of each other, and their telescopic movements do not interfere with each other.

[0011] Optionally, in the above-mentioned telescopic arm boom, when the telescopic arm boom is placed horizontally, the first cylinder, the second cylinder...the N-1th cylinder are arranged in parallel from bottom to top.

[0012] Optionally, in the above-mentioned telescopic boom frame, N=4, and the telescopic boom frame includes a first boom section, a second boom section, a third boom section, a fourth boom section, and a first oil cylinder, a second oil cylinder, and a third oil cylinder.

[0013] Optionally, in the above-mentioned telescopic arm bracket, one end of the first piston rod away from the first cylinder is connected to the arm end of the first section arm, and one end of the first cylinder close to the first piston rod is connected to the arm end of the second section arm.

[0014] Optionally, in the above-mentioned telescopic arm bracket, the end of the first cylinder away from the first piston rod is connected to a first guide wheel, and the first guide wheel can be guided and rolled inside the fourth arm.

[0015] Optionally, in the above-mentioned telescopic arm bracket, one end of the second piston rod away from the second cylinder is connected to the arm tail of the second section arm, and one end of the second cylinder close to the second piston rod is connected to the arm tail of the third section arm.

[0016] Optionally, in the above-mentioned telescopic arm bracket, the end of the second cylinder away from the second piston rod is connected to a second guide wheel, and the second guide wheel can be guided and rolled inside the fourth arm.

[0017] Optionally, in the above-mentioned telescopic arm bracket, one end of the third piston rod of the third cylinder away from the third cylinder barrel of the third cylinder is connected to the arm tail of the third section arm, and one end of the third cylinder barrel away from the third piston rod is connected to the arm head of the fourth section arm.

[0018] Optionally, in the above-mentioned telescopic arm bracket, each cylinder is connected to the oil tank through a switching valve.

[0019] A crane comprises the telescopic boom as described above.

[0020] In the telescopic boom frame and crane of the present application, two adjacent boom sections that are nested with each other are connected by oil cylinders, which eliminates the use of rope racks, enhances the impact resistance of the telescopic boom frame, and enhances the structural rigidity. Therefore, the telescopic boom crawler crane using the telescopic boom frame is not only suitable for lifting conditions, but also can be expanded to complex conditions of vibration and impact such as down-the-hole drilling, pile pulling, and vibratory hammer operations; further, the oil cylinders of the telescopic boom frame are independent of each other, and the telescopic movement of each cylinder does not interfere with each other, so the oil cylinders do not need to be telescoped in sequence, thereby driving the arbitrary telescopic movement of each boom section independently of each other; in specific circumstances, only one or several boom sections can be extended, which not only improves the degree of freedom of telescopic movement of each boom section, making the crane have higher working efficiency, but also avoids the energy consumption caused by synchronously driving all boom sections. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0022] Figure 1 This is a schematic structural diagram of a telescopic arm support according to an embodiment of the present application;

[0023] Figure 2 This is a structural schematic diagram of the telescopic arm frame of the embodiment of the present application in a tilted state;

[0024] Figure 3 This is a structural schematic diagram of the telescopic arm frame of the embodiment of the present application in a horizontal state;

[0025] Figure 4 This is a schematic diagram of the structure in which all the arms of the embodiment of the present application are in a retracted state;

[0026] Figure 5 This is a schematic diagram of the structure in which all the arms of the embodiment of the present application are in an extended state;

[0027] Figure 6 A connection diagram of each oil cylinder and a switching valve in an embodiment of the present application;

[0028] Figure 7 It is a schematic diagram of the structure of a rope-type telescopic boom in the prior art.

[0029] superior Figure 1-6 middle:

[0030] 1. First boom; 2. Second boom; 3. Third boom; 4. Fourth boom; 5. First oil cylinder; 6. Second oil cylinder; 7. Third oil cylinder; 8. First guide wheel; 9. Second guide wheel; 10. First switching valve; 11. Second switching valve; 12. Third switching valve;

[0031] 51. a first piston rod; 52. a first cylinder;

[0032] 61. second piston rod; 62. second cylinder barrel;

[0033] 71. third piston rod; 72. third cylinder barrel;

[0034] 511, first connection point;

[0035] 521, second connection point;

[0036] 611, the third connection point;

[0037] 621, the fourth connection point;

[0038] 711, fifth connection point;

[0039] 721. The sixth connection point. DETAILED DESCRIPTION

[0040] The present application provides a telescopic boom and a crane.

[0041] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0042] Please see attached Figure 7 , showing a rope-row telescopic boom in the prior art, which is a five-section rope-row telescopic boom, which needs to arrange five sets of rope-row components inside, and realize the synchronous extension of the five-section boom through the second traction rope group B, the third traction rope group C, and the fifth traction rope group E, and realize the synchronous retraction of the boom through the first traction rope group A, the second traction rope group B, and the fourth traction rope group D; Obviously, the multi-section arms of the above rope-row telescopic boom can only be telescopically moved synchronously, and the degree of freedom of telescopic movement of each section of the boom is poor. In addition, due to the structural characteristics of the rope-row components, it has poor rigidity and poor impact resistance. When the telescopic boom is under strong vibration conditions, the telescopic boom controlled by the rope-row components is easily damaged.

[0043] like Figure 1-Figure 3 As shown, an embodiment of the present application provides a telescopic boom frame, which is arranged on a crane; preferably, the telescopic boom frame is arranged on a telescopic crawler crane. The telescopic boom frame includes a first boom section 1, a second boom section 2, ... an N-th boom section, which are sequentially sleeved from the outside to the inside; N is a positive integer, and N≥3. The telescopic boom frame also includes a first cylinder 5, a second cylinder 6, ... an N-1-th cylinder; the number of cylinders arranged on the telescopic boom frame is 1 less than the number of boom sections; the first cylinder 5 includes a first piston rod 51 and a first cylinder barrel 52; the second cylinder 6 includes a second piston rod 61 and a second cylinder barrel 62; the third cylinder 7 includes a third piston rod 71 and a third cylinder barrel 72... The N-1-th cylinder includes an N-1-th piston rod and an N-1-th cylinder barrel.

[0044] At least part of the first oil cylinder 5 is located inside the Nth arm along the axial direction of the telescopic boom frame. One of the first piston rod 51 and the first cylinder barrel 52 is connected to the first arm 1, and the other is connected to the second arm 2, so that the extension or retraction movement of the second arm 2 relative to the first arm 1 can be achieved through the relative telescopic movement of the first piston rod 51 and the first cylinder barrel 52.

[0045] At least part of the second oil cylinder 6 is located inside the Nth arm along the axial direction of the telescopic boom frame, and one of the second piston rod 61 and the second cylinder 62 is connected to the second arm 2, and the other is connected to the third arm 3, so that the extension or retraction movement of the third arm 3 relative to the second arm 2 can be achieved through the relative telescopic movement of the second piston rod 61 and the second cylinder 62.

[0046] According to the above rule, oil cylinders are sequentially arranged between two adjacent arms that are nested with each other, until the N-1th oil cylinder: at least part of the N-1th oil cylinder along the axial direction of the telescopic arm frame is located inside the N-1th arm, and one of its N-1th piston rod and N-1th cylinder barrel is connected to the N-1th arm, and the other is connected to the N-1th arm, so that the extension or retraction movement of the N-1th arm relative to the N-1th arm can be achieved through the relative telescopic movement of the N-1th piston rod and the N-1th cylinder barrel.

[0047] The first oil cylinder 5, the second oil cylinder 6 ... the N-1 oil cylinder are arranged at positions independently of each other, and their telescopic movements do not interfere with each other.

[0048] It should be noted that when the second boom 2 telescopes relative to the first boom 1, the other booms sleeved in the second boom 2 move synchronously with the second boom 2; when the third boom 3 telescopes relative to the second boom 2, the other booms sleeved in the third boom 3 move synchronously with the third boom 3... and so on. The telescopic movement of the second boom 2 specifically refers to the telescopic movement of the second boom 2 relative to the first boom 1; the telescopic movement of the third boom 3 specifically refers to the telescopic movement of the third boom 3 relative to the second boom 2;... and so on; the telescopic movement of the Nth boom specifically refers to the telescopic movement of the Nth boom relative to the N-1th boom.

[0049] The two adjacent arms that are nested with each other in the telescopic boom frame of the present application are connected by an oil cylinder, which eliminates the use of rope racks, enhances the impact resistance of the telescopic boom frame, and enhances the overall structural rigidity of the telescopic boom frame. Therefore, the telescopic boom crawler crane using the telescopic boom frame is not only suitable for lifting conditions, but also can be expanded to complex conditions of vibration and impact such as down-the-hole drilling, pile pulling, and vibratory hammer operation.

[0050] Furthermore, the cylinders of the telescopic boom are independent of each other, and their telescopic movements do not interfere with each other. Therefore, the cylinders do not need to be extended or retracted in sequence, thereby driving the independent and arbitrary telescopic movements of each boom section. Under certain circumstances, only one or several boom sections can be extended, which not only improves the degree of freedom of telescopic movement of each boom section, making the crane more efficient, but also avoids the energy consumption caused by synchronously driving all boom sections.

[0051] In certain embodiments of the present application, when the telescopic boom is placed horizontally, the first cylinder 5, the second cylinder 6, ... the N-1 cylinder are arranged in parallel from bottom to top. Figure 1 Direction indicated by the arrow.

[0052] It should be noted that the first oil cylinder 5 is arranged at a position closer to the construction ground.

[0053] Please refer to the attached Figure 2 , taking the four-section arm and three-cylinder as an example for force analysis, when the telescopic arm frame tilts upward When: the axial force of the first oil cylinder 5 is The axial force of the second oil cylinder 6 is The axial force of the third oil cylinder 7 is The tilt angle Attached Figure 2 The angle marked in the figure; the axial force is along the length direction of the piston rod and cylinder barrel of each cylinder, that is, Figure 2 The direction is indicated by the arrow. G is the hoisting weight, F1 is the weight of the first boom 1, F2 is the weight of the second boom 2, F3 is the weight of the third boom 3, F4 is the weight of the fourth boom 4, FⅠ is the weight of the first cylinder 5, FⅡ is the weight of the second cylinder 6, and FⅢ is the weight of the third cylinder 7; G total is the combined weight of the hoisting weight, each boom, and each cylinder, G total = G + F4 + F3 + F2 + FⅢ + FⅡ + FⅠ; Appendix Figure 2 The axial force decomposition diagram of the first oil cylinder 5 is given as an example.

[0054] As can be seen from the above, the first oil cylinder 5 is subjected to the worst force (i.e., the greatest force), so it is arranged in a position closer to the construction ground in the Nth boom, and the vibration impact is transmitted from bottom to top. The first oil cylinder 5, which is subjected to the worst force, is arranged at a lower position, which has good stability, thereby making the telescopic boom crawler crane more reliable in anti-impact when it is in complex working conditions on the construction site such as down-the-hole drilling, pile pulling, and vibration hammer operation. Furthermore, since the first oil cylinder 5 is subjected to the greatest force, in order for the telescopic boom to be able to perform telescopic movements normally, the cylinder diameter of the first oil cylinder 5 is made the largest. In combination with the cylinder diameter size and the vibration impact, the first oil cylinder 5 is arranged at a lower position, which has a good buffering effect and better stability.

[0055] In certain embodiments of the present application, N=4, and the telescopic boom frame includes a first boom 1 , a second boom 2 , a third boom 3 , a fourth boom 4 , and a first oil cylinder 5 , a second oil cylinder 6 , and a third oil cylinder 7 .

[0056] Furthermore, one end of the first piston rod 51 away from the first cylinder 52 is connected to the arm tail of the first section arm 1 , and one end of the first cylinder 52 close to the first piston rod 51 is connected to the arm tail of the second section arm 2 .

[0057] Please refer to the attached Figure 1 , 3 , the first piston rod 51 is connected to the first section arm 1 at the first connection point 511; the first cylinder 52 is connected to the second section arm 2 at the second connection point 521. As described above, the connection between the first section arm 1 and the second section arm 2 is realized, which is convenient for connection operations at various connection points, saving time and effort.

[0058] In certain embodiments of the present application, one end of the first cylinder 52 away from the first piston rod 51 is connected to the first guide wheel 8 , and the first guide wheel 8 can be guided and rolled inside the fourth section arm 4 .

[0059] The first guide wheel 8 provides a support point for the end of the first cylinder 52 away from the first piston rod 51, ensuring the support setting strength of the first cylinder 52; and when the first cylinder 52 telescopes relative to the first piston rod 51, the first guide wheel 8 provides a supporting and guiding function for the telescopic movement of the first cylinder 52, ensuring that the telescopic movement of the first cylinder 52 is more stable and reliable.

[0060] In certain embodiments of the present application, one end of the second piston rod 61 away from the second cylinder 62 is connected to the arm tail of the second section arm 2 , and one end of the second cylinder 62 close to the second piston rod 61 is connected to the arm tail of the third section arm 3 .

[0061] Please refer to the attached Figure 1 , 3 , the second piston rod 61 is connected to the second section arm 2 at the third connection point 611; the second cylinder 62 is connected to the third section arm 3 at the fourth connection point 621. As described above, the connection between the second section arm 2 and the third section arm 3 is realized, which is convenient for connection operations at various connection points, saving time and effort.

[0062] Furthermore, the second connection point 521 and the third connection point 611 are both located at the end of the second boom 2. Therefore, when the second boom 2 is telescopically moved relative to the first boom 1, the second boom 2 can drive the second cylinder 6 and the third boom 3 connected to the second cylinder 6 to move synchronously.

[0063] In certain embodiments of the present application, one end of the second cylinder 62 away from the second piston rod 61 is connected to the second guide wheel 9 , and the second guide wheel 9 can be guided and rolled inside the fourth section arm 4 .

[0064] The second guide wheel 9 provides a support point for the end of the second cylinder 62 away from the second piston rod 61, ensuring the support setting strength of the second cylinder 62; and when the second cylinder 62 telescopically moves relative to the second piston rod 61, the second guide wheel 9 provides a supporting and guiding function for the telescopic movement of the second cylinder 62, ensuring that the telescopic movement of the second cylinder 62 is more stable and reliable.

[0065] In certain embodiments of the present application, one end of the third piston rod 71 away from the third cylinder 72 is connected to the arm tail of the third section arm 3, and one end of the third cylinder 72 away from the third piston rod 71 is connected to the arm head of the fourth section arm 4.

[0066] Please refer to the attached Figure 1 , 3 , the third piston rod 71 is connected to the third boom 3 at the fifth connection point 711; the third cylinder 72 is connected to the fourth boom 4 at the sixth connection point 721. As described above, the connection between the third cylinder 7 and the fourth boom 4 is realized, which is convenient for connection operation at each connection point, saving time and effort.

[0067] Furthermore, the fourth connection point 621 and the fifth connection point 711 are both located at the end of the third boom 3. Therefore, when the third boom 3 is telescopically moved relative to the second boom 2, the third boom 3 can drive the third cylinder 7 and the fourth boom 4 connected to the third cylinder 7 to move synchronously.

[0068] Furthermore, the fifth connection point 711 and the sixth connection point 721 are respectively located at two ends of the third piston rod 71 and the third cylinder 72 that are far away from each other, thereby ensuring that there are connection points at both ends of the third oil cylinder 7 that are relatively located. There is no need to provide a guide wheel on the third cylinder 72, so that the reliability of the connection of the third oil cylinder 7 and the reliability of the telescopic movement of the third cylinder 72 can be guaranteed.

[0069] Please refer to the accompanying drawings. In some embodiments of the present application, each oil cylinder is connected to the oil tank through a switching valve. Take a four-section arm with three oil cylinders as an example, that is, the first oil cylinder 5, the second oil cylinder 6, and the third oil cylinder 7 are all connected to the oil tank through a switching valve.

[0070] As mentioned above, by controlling the switching valve, it is possible to realize the delivery of hydraulic oil to the first cylinder 5 and / or the second cylinder 6 and / or the third cylinder 7, thereby accurately and reliably selectively controlling the arbitrary telescopic movement of one or several cylinders out of sequence, thereby driving the arbitrary telescopic movement of each boom section independently of each other, which not only improves the degree of freedom of telescopic movement of each boom section, making the crane more efficient, but also avoids the energy consumption caused by synchronously driving all the boom sections.

[0071] Specifically, the switching valve includes a first switching valve 10, a second switching valve 11, and a third switching valve 12; the first switching valve 10, the second switching valve 11, and the third switching valve 12 are all electrically controlled valves. The first oil cylinder 5, the second oil cylinder 6, and the third oil cylinder 7 are connected in parallel, the first oil cylinder 5 is connected to the oil tank through the first switching valve 10, the second oil cylinder 6 is connected to the oil tank through the second switching valve 11, and the third oil cylinder 7 is connected to the oil tank through the third switching valve 12; when a certain section arm needs to be telescopically moved, the switching valve under the oil cylinder corresponding to the section arm is controlled to work, and the oil inlet or outlet of the rod chamber and the rodless chamber of the corresponding oil cylinder are controlled by the corresponding switching valve, so that the telescopic movement of the corresponding oil cylinder can be controlled, and then the telescopic movement of the corresponding section arm can be controlled.

[0072] In summary, the present application also provides a crane, which comprises a telescopic boom as described above.

[0073] Optionally, the crane is a telescopic boom crawler crane.

[0074] Since the crane of the present application includes the telescopic arm jib described above, the beneficial effects brought about by the telescopic arm jib of the crane can be found above and will not be described in detail here.

[0075] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be pointed out that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. must be possessed by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation. The above details do not limit the present application to the use of the above specific details to be implemented.

[0076] The block diagrams of the devices, apparatuses, equipment, and systems involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagram. As will be appreciated by those skilled in the art, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, referring to "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The words "such as" used here refer to the phrase "such as but not limited to", and can be used interchangeably with them.

[0077] It should also be noted that in the apparatus, device and method of the present application, each component or each step can be decomposed and / or recombined. Such decomposition and / or recombination should be regarded as equivalent solutions of the present application.

[0078] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

[0079] It should be understood that the qualifiers "first", "second", "third", "fourth", "fifth" and "sixth" used in the description of the embodiments of the present application are only used to more clearly explain the technical solutions and cannot be used to limit the scope of protection of the present application.

[0080] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A telescopic boom, characterized in that: It includes a first boom, a second boom, ... an Nth boom which are sequentially sleeved from the outside to the inside, N ≥ 3; the telescopic boom frame also includes: A first oil cylinder, at least part of which along its axial direction is located inside the Nth section arm, and one of its first piston rod and first cylinder barrel is connected to the first section arm, and the other is connected to the second section arm; A second oil cylinder, at least part of which along its axial direction is located inside the Nth section arm, and one of its second piston rod and second cylinder barrel is connected to the second section arm, and the other is connected to the third section arm; …… The N-1 oil cylinder is located inside the N-1 arm along at least a portion of its axial direction, and one of its N-1 piston rod and its N-1 cylinder barrel is connected to the N-1 arm, and the other is connected to the N-1 arm; Among them, the first oil cylinder, the second oil cylinder ... the N-1th oil cylinder are arranged at positions independently of each other, and their telescopic movements do not interfere with each other.

2. The telescopic boom according to claim 1, characterized in that: When the telescopic boom is placed horizontally, the first cylinder, the second cylinder ... the N-1 cylinder are arranged in parallel from bottom to top.

3. The telescopic boom according to claim 1, characterized in that: N=4, the telescopic boom frame includes a first boom section, a second boom section, a third boom section, a fourth boom section, and a first oil cylinder, a second oil cylinder, and a third oil cylinder.

4. The telescopic boom according to claim 3, characterized in that: One end of the first piston rod away from the first cylinder is connected to the arm end of the first section arm, and one end of the first cylinder close to the first piston rod is connected to the arm end of the second section arm.

5. The telescopic boom according to claim 4, characterized in that: A first guide wheel is connected to one end of the first cylinder away from the first piston rod, and the first guide wheel can be guided and rolled inside the fourth arm.

6. The telescopic boom according to claim 3, characterized in that: One end of the second piston rod away from the second cylinder is connected to the arm tail of the second section arm, and one end of the second cylinder close to the second piston rod is connected to the arm tail of the third section arm.

7. The telescopic boom according to claim 6, characterized in that: A second guide wheel is connected to one end of the second cylinder away from the second piston rod, and the second guide wheel can be guided and rolled inside the fourth arm.

8. The telescopic boom according to claim 3, characterized in that: One end of the third piston rod of the third oil cylinder away from the third cylinder barrel of the third oil cylinder is connected to the arm tail of the third section arm, and one end of the third cylinder barrel away from the third piston rod is connected to the arm head of the fourth section arm.

9. The telescopic boom according to any one of claims 1 to 8, characterized in that: Each oil cylinder is connected to the oil tank through a switching valve.

10. A crane, characterized in that: It comprises a telescopic boom as claimed in any one of claims 1 to 9.

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