Crane telescopic system cylinder arm pin control device and method thereof

Abstract

The invention discloses a crane telescopic system cylinder arm pin control device and method, the crane telescopic system cylinder arm pin control device comprises a controller, an arm position detection device and a cylinder pin fixed point detection device, and the arm position detection device and the cylinder pin fixed point detection device are both installed on a telescopic arm (7); wherein the arm position detection device comprises a first proximity switch (1), a second proximity switch (2) and an arm position detection metal strip (12), the first proximity switch (1) and the second proximity switch (2) are installed on a telescopic oil cylinder head (13), the arm position detection metal strip (12) is installed on each section of suspension arm of a telescopic arm (7), and the controller is electrically connected with the first proximity switch (1) and the second proximity switch (2). The invention mainly aims to solve the problems of low cylinder pin insertion and extraction efficiency and incapability of accurate control in the existing telescopic system, realize accurate control of cylinder pin insertion and extraction, and improve the telescopic efficiency of the crane.

Description

Technical Field

[0001] The invention relates to a crane telescopic system cylinder arm pin control device and method thereof, belonging to the technical field of single-cylinder latch-type telescopic systems in the field of engineering machinery. Background Art

[0002] Cranes are important equipment widely used in engineering construction. Their main functions include lifting, telescoping, luffing and slewing. Telescoping refers to the change of the arm length of the crane boom driven by the oil cylinder. With the fierce market competition, users have higher and higher requirements for the arm length of cranes. Products with 6 booms and above mostly use the telescopic method of single cylinder pins. Compared with the rope-type telescopic mechanism, it has the advantages of the number of boom sections not being restricted by the arrangement of the telescopic mechanism and light weight, which can meet the needs of long arm length and improve the stability of the whole machine.

[0003] The single-cylinder latch telescopic mechanism includes a lifting arm and a telescopic cylinder. The arm pin is located at the tail of each section of the telescopic arm. The arm pin is locked in the arm hole of the outer section arm under the action of spring force, and the arms can be rigidly locked by the arm pin. The cylinder pin can move in the left and right directions on both sides of the telescopic cylinder head, and extend into the pin holes on both sides of the boom to be rigidly locked with the arm. At this time, the cylinder and the boom are locked as one. The extension process of the single-cylinder latch telescopic system is that the telescopic cylinder moves to the position of a certain section of the boom and releases the cylinder pin to the cylinder pin hole to achieve rigid locking between the cylinder and the boom, and then pulls out the arm pin to release the rigid locking between the two sections of the boom. The cylinder drives the boom to extend to a predetermined position, and releases the arm pin to the arm pin hole of the previous section of the boom to achieve rigid locking of the two sections of the boom; the cylinder pin is pulled out to release the rigid locking between the telescopic cylinder and the boom, and the telescopic cylinder moves to the next section of the boom, and so on to achieve the extension and retraction of multiple sections of the boom.

[0004] The single-cylinder latch telescopic mechanism is based on the arm position detection device, the cylinder arm pin detection device and the cylinder length detection device, which controls the switching back and forth of the cylinder pin mechanism and the arm pin mechanism on the telescopic cylinder head, and cooperates with the extension and retraction of the telescopic cylinder to realize the extension and retraction of the boom section by section. The telescopic cylinder piston rod is fixed to the basic arm, and the cylinder head is fixed to the cylinder barrel. Due to the complexity of the cylinder arm pin mechanism control, the single-cylinder latch telescopic system has problems such as low telescopic efficiency, inability to telescope, and shaking due to the lack of precise control. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a crane telescopic system cylinder arm pin control device and method. Based on the prior art, the present invention improves the arm position detection device to more accurately judge the positions of the cylinder pin and the cylinder pin hole, thereby achieving precise control of the insertion and extraction of the cylinder pin and improving the telescopic efficiency of the crane; reducing abnormal noise during the arm pin insertion process and improving the control performance.

[0006] Preferably, the present invention provides a crane telescopic system cylinder arm pin control device, comprising a controller, an arm position detection device and a cylinder pin fixed point detection device, wherein the arm position detection device and the cylinder pin fixed point detection device are both installed on the telescopic arm; Among them, the arm position detection device includes a first proximity switch, a second proximity switch and an arm position detection metal strip, the first proximity switch and the second proximity switch are installed on the cylinder head of the telescopic cylinder, the arm position detection metal strip is installed on each boom section of the telescopic arm, and the controller is electrically connected to the first proximity switch and the second proximity switch.

[0007] Preferably, a cylinder pin detection plate is included, and the cylinder pin detection plate is installed at the arm tail of each boom section of the telescopic arm.

[0008] Preferably, the cylinder pin fixed-point detection device includes a fixed-point release proximity switch, which is installed between the first proximity switch and the second proximity switch, and the fixed-point release proximity switch is electrically connected to the controller.

[0009] Preferably, the cylinder pin fixed-point detection device includes a fixed-point release cylinder pin detection metal bar and a fourth proximity switch. The fixed-point release cylinder pin detection metal bar is installed on each boom section of the telescopic arm, and the fourth proximity switch is installed on the other side of the cylinder pin. The fourth proximity switch is electrically connected to the controller.

[0010] Preferably, a crane telescopic system cylinder arm pin control method is based on any one of the crane telescopic system cylinder arm pin control devices described above, and performs the following steps: Step 1, extending the boom of the telescopic arm; Step 2, determining whether the first proximity switch or the second proximity switch detects the arm position detection metal bar, if the first proximity switch or the second proximity switch detects the arm position detection metal bar, the boom of the telescopic arm extends the boom at a first preset speed; Step 3, determining whether the fixed-point release proximity switch or the fourth proximity switch detects the fixed-point release cylinder pin detection metal strip, if the fixed-point release proximity switch or the fourth proximity switch detects the fixed-point release cylinder pin detection metal strip, the oil cylinder stops moving; Step 4, determine whether the fixed-point release proximity switch or the fourth proximity switch detects the fixed-point release cylinder pin detection metal bar. If the fixed-point release proximity switch or the fourth proximity switch detects the fixed-point release cylinder pin detection metal bar, release the cylinder pin and lock the telescopic arm.

[0011] Preferably, in step 2, if the first proximity switch or the second proximity switch does not detect the arm position detection metal bar, step 1 is executed.

[0012] Preferably, in step three, if the fixed-point release proximity switch or the fourth proximity switch does not detect the fixed-point release cylinder pin detection metal bar, the boom of the telescopic arm extends the boom at the first preset speed, and this step is repeated.

[0013] Preferably, in step four, if the fixed-point release proximity switch or the fourth proximity switch does not detect the fixed-point release cylinder pin detection metal bar, the telescopic arm is extended in the reverse direction at the second preset speed, and this step is repeated.

[0014] The beneficial effects achieved by the present invention are: The present invention changes the existing arm pin hole position to a delayed release, inserts the arm pin by retracting the arm, and when the arm pin is released, the arm pin is directly buckled due to the inertia of the retracted arm. This solution can avoid the collision sound between the cylinder pin and the cylinder pin hole when the arm is extended to be retracted in the prior art, and at the same time reduce the sound of the buckle and improve the control performance. The present invention improves the arm position detection device to more accurately judge the position of the cylinder pin and the cylinder pin hole, realize accurate control of inserting and pulling the cylinder pin, and improve the telescopic efficiency of the crane. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solution of the present application, the drawings required for use in the embodiments are briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0016] Figure 1 is a structural diagram of cylinder arm pin control in some embodiments of the present application; Figure 2 is a structural diagram of a fixed-point release cylinder pin detection strip in some embodiments of the present application; Figure 3 is a cylinder pin control logic diagram in some embodiments of the present application; Figure 4 is a front view of a staggered cylinder pin fixed-point detection arrangement in some embodiments of the present application; Figure 5 is a rear view of a staggered cylinder pin fixed-point detection arrangement in some embodiments of the present application; Figure 6 It is a structural diagram of the arm pin release in some embodiments of the present application.

[0017] The meaning of the reference numerals are as follows: 1-first proximity switch; 2-second proximity switch; 3-fixed-point release proximity switch; 4-fixed-point release cylinder pin detection metal strip; 5-fourth proximity switch; 6-cylinder pin; 7-telescopic arm; 8-first arm position hole; 9-second arm position hole; 10-third arm position hole; 11-front release arm position hole; 12-arm position detection metal strip. DETAILED DESCRIPTION

[0018] If the descriptions of "first" and "second" etc. are involved in the present invention, they are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0019] The current mainstream single-cylinder latch uses 4 proximity switches to detect the arm position. Each arm section is equipped with an arm position detection metal strip at the position corresponding to the four proximity switches, that is, each arm section corresponds to the signal of a different proximity switch. The locking control of the cylinder pin is through arm position detection and early release. That is, the arm position detection metal strip on the boom is longer, and the cylinder pin is released when the proximity switch on the cylinder head of the telescopic cylinder detects the arm position. At this time, the cylinder pin is not in the position of the cylinder pin hole, and is attached to the outside of the cylinder pin hole under the action of the spring reset force. Continue to extend or retract the arm until the cylinder pin is aligned with the cylinder pin hole. The cylinder pin automatically pops out and enters the cylinder pin hole to achieve locking of the cylinder and the boom.

[0020] The cylinder pin is unlocked by pulling out the cylinder pin while extending or retracting it at a low speed. Generally, there are no problems. If the cylinder pin is too tight to the cylinder pin hole of the boom, it may sometimes be difficult to pull it out, and the cylinder pin needs to be extended and retracted back and forth to pull it out.

[0021] The arm position detection metal bar on the boom is long. When the proximity switch touches the metal bar and detects the arm position, the cylinder pin is released. At this time, the cylinder pin hole is not in the corresponding position, and it is necessary to find the cylinder pin hole position at a low speed, which wastes time. If the deceleration effect is not good, it may overextend. At this time, the cylinder continues to move and cannot lock the cylinder pin in the cylinder pin hole. It is not until the cylinder moves to the arm position signal and the program allows the telescopic cylinder to move back and continue to release the cylinder pin.

[0022] Moreover, the cylinder pin is released in advance, and the cylinder pin is tightly attached to the outer wall of the cylinder pin hole under the action of the spring return force. There is friction between the oil cylinder and the boom, which can easily cause the oil cylinder to shake and make abnormal noise when moving at low speed. It is also possible that the front few sections of the arm are pulled out due to the friction, causing the boom to retract and make abnormal noise when it is subsequently inverted.

[0023] Based on the existing technical solution, if the detection strip is directly shortened and aligned with the cylinder pin when the arm position is detected, it is very easy to cause the vehicle to fail to stop accurately due to inertia when the arm position is detected, resulting in over-positioning.

[0024] At present, the control of arm pin locking adopts early release, that is, if you want to lock the arm pin hole at 92%, the arm pin is released when the cylinder length line is detected at about 90%, and the cylinder is switched to low-speed movement. At this time, the arm pin is half released on the inner surface of the boom, and it moves forward at a low speed to the arm pin hole. The arm pin pops out and the arm is extended and retracted. The arm pin is released at a position about 2%~3% in front of the arm pin hole, and the speed is switched to low speed. At this time, the arm pin is half released on the inner surface of the boom and moves forward at a low speed. Due to friction, the low-speed movement of the cylinder is prone to jitter, and the friction can easily bring out the front few sections of the arm. Wait until the arm pin hole position is released and then buckled. As the cylinder changes from extension to contraction, the cylinder pin and the cylinder pin hole change from front contact to back contact. The cylinder hits the boom and makes a sound, and the boom changes from static to retracted, which will also have a large impact sound, causing noise pollution.

[0025] The disadvantages of the prior art 1 and 2 are as follows: 1. There are accuracy problems in measuring the length, which requires calibration testing and a long debugging time; 2. There is still a collision sound between the cylinder pin and the cylinder pin hole.

[0026] In view of the shortcomings of the prior art, the present invention proposes a method and device for controlling the cylinder arm pin of a crane telescopic system, which includes an arm position detection device and a controller, and also includes a cylinder pin fixed point detection device. The cylinder pin fixed point detection device includes a proximity switch for detecting the addition of a fixed point release cylinder pin, and a cylinder pin detection plate for detecting the fixed point release cylinder pin signal is added to the tail of each arm on the arm detection plate of the boom.

[0027] The main purpose of the present invention is to solve the problems of low efficiency and inability to accurately control the insertion and extraction of cylinder pins in existing telescopic systems, to achieve accurate control of the insertion and extraction of cylinder pins, and to improve the telescopic efficiency of cranes. Figure 1 , the present application provides a crane telescopic system cylinder arm pin control device, characterized in that it includes a controller, an arm position detection device and a cylinder pin fixed point detection device, the arm position detection device and the cylinder pin fixed point detection device are both installed on the telescopic arm 7; The arm position detection device includes a first proximity switch 1, a second proximity switch 2 and an arm position detection metal strip 12. The first proximity switch 1 and the second proximity switch 2 are installed on the telescopic cylinder head 13. The arm position detection metal strip 12 is installed on each boom section of the telescopic boom 7. The controller is electrically connected to the first proximity switch 1 and the second proximity switch 2. The cylinder pin fixed point detection device includes a proximity switch for detecting the addition of a fixed point release cylinder pin, and a cylinder pin detection piece for detecting the fixed point release cylinder pin signal is added to the boom detection piece of the boom at the end of each boom section.

[0028] The present invention designs a control device for a single-cylinder latch and retractable system of a crane and a cylinder pin control method. By improving an arm position detection device to realize a method for delaying arm pin control, the positions of the cylinder pin and the cylinder pin hole can be judged more accurately, precise control of inserting and pulling the cylinder pin can be achieved, abnormal noise during the arm pin insertion process can be reduced, and the telescopic efficiency and control performance of the crane can be improved.

[0029] The present invention designs a control device for a single-cylinder latch and retractable system of a crane and a cylinder pin control method. By improving an arm position detection device to realize a method for delaying arm pin control, the positions of the cylinder pin and the cylinder pin hole can be judged more accurately, precise control of inserting and pulling the cylinder pin can be achieved, abnormal noise during the arm pin insertion process can be reduced, and the telescopic efficiency and control performance of the crane can be improved.

[0030] A control method for a crane single cylinder latch extension system includes the following points, as shown in the logic diagram When the arm position is found by extending the arm, the first proximity switch and the second proximity switch of the arm position detection detect the arm position signal, the telescopic cylinder switches to low-speed mode, and continues to extend the arm at low speed. When the third proximity switch signal of fixed-point release is detected, the cylinder stops moving. If the fixed-point release signal is still maintained after the cylinder stops, it means that the cylinder pin is facing the cylinder pin hole. At this time, the cylinder pin can be directly released to lock the cylinder pin. If the fixed-point release signal is lost after the cylinder stops, the cylinder needs to move in the opposite direction at low speed until the fixed-point release signal is detected, then the cylinder pin is released to lock the cylinder pin.

[0031] Furthermore, the cylinder length line signal can be used to assist in detection, that is, when the arm position is found by extending the arm, when the first proximity switch and the second proximity switch of the arm position detection detect the arm position signal, the distance L from the arm position detection metal bar to the third proximity switch of the fixed-point release can be calculated, and the cylinder moves at a low speed to the position where the cylinder length line changes by L and stops, to prevent the third proximity switch of the fixed-point release from failing and affecting this function.

[0032] Furthermore, a fifth and seventh fixed-point release proximity switch can be added to each of the two arm position detection sliders of the telescopic cylinder, that is, there are two fixed-point release proximity switches, so that redundant detection is achieved. Even if one proximity switch is broken, it will not affect the function.

[0033] Further, according to the above-mentioned scheme of adding two fixed-point proximity switches, the two proximity switches correspond to the seventh proximity switch on the front side of the cylinder pin and the fifth proximity switch on the rear side of the cylinder pin, respectively. As shown in one of the implementation schemes in the figure below, the left side corresponds to the cylinder pin contacting the front of the cylinder pin hole and being located in the middle of the arm pin hole, and the right side corresponds to the cylinder pin contacting the back of the cylinder pin hole and being located in the middle. The positions are staggered, which can better control the arm position. In this way, not only can the fixed-point release of the cylinder pin be achieved, but also the position of the cylinder pin in the cylinder pin hole can be judged at other times, that is, the left and right proximity switches have signals at the same time, indicating that the cylinder pin is in the middle of the cylinder pin hole, the seventh proximity switch on the left has a signal, and the fifth proximity switch on the right has no signal, indicating that the cylinder pin is in front of the cylinder pin hole, the seventh proximity switch on the left has no signal, and the fifth proximity switch on the right has a signal, indicating that the cylinder pin is behind the cylinder pin hole. In this way, more precise control can be achieved when the cylinder is looking for the arm position at a low speed. When unlocking the cylinder pin, operations can be performed according to the state of the cylinder pin. If the cylinder pin is in the middle, it can be unlocked directly. If the cylinder pin is in the front or back, the cylinder pin can be moved to the center of the cylinder pin hole by controlling the oil cylinder to move at a low speed, thereby unlocking the cylinder pin while extending it or unlocking it while retracting it, which can greatly improve the success rate of unlocking the cylinder pin.

[0034] Furthermore, the existence of the fixed-point release proximity switch can make up for the failure of the original arm position detection proximity switch. The fixed-point release proximity switch can be used as a backup proximity switch for arm position detection, thereby improving the reliability of the telescopic system.

[0035] A control method for a crane single-cylinder latch telescopic system also includes a delayed release method for an arm pin. The prior art solution has three arm pin hole positions, and the arm extension control program is to perform early release at the 2% to 3% advance position. The present invention changes the existing arm pin hole position to a delayed release, that is, a 1% to 3% delay in release, and then inserts the arm pin by retracting the arm. While releasing the arm pin, the inertia of the retracted arm directly completes the undercut. This solution can avoid the impact sound between the cylinder pin and the cylinder pin hole when the arm extension is changed to retraction in the prior art, and reduce the sound of the undercut.

[0036] The invention includes the structure, the improvement of the boom detection metal strip, the improvement of the oil cylinder head proximity switch and the control program. Telescopic oil cylinder: telescopically drives the boom to extend and retract.

[0037] Arm pin: located at the tail of each section of the telescopic arm, it mainly consists of an arm pin, a spring and an arm pin bolt. The arm pin has three states: unlocked state, locked state and intermediate state. Arm pin unlocking means that the arm pin is fully retracted (the state is identified by the proximity switch). At this time, there is no rigid lock between the two sections of the boom. Arm pin locking means that the arm pin is fully extended (the state is identified by the proximity switch) to the arm pin hole of the upper arm. At this time, the two sections of the boom are rigidly locked. The intermediate state of the arm pin is the state where the arm pin is not fully extended (this state is not identified by the proximity switch).

[0038] Cylinder pin: There are pins on both sides of the telescopic cylinder head that can move in the left and right directions. Because they are installed on the telescopic cylinder, they are called cylinder pins. The cylinder pin has three states: unlocked state, locked state and intermediate state. Cylinder pin unlocking means that the cylinder pin is fully retracted to the cylinder head (the state is identified by the proximity switch). At this time, the cylinder and the boom are directly non-rigidly locked. Cylinder pin locking means that the cylinder pin is fully extended (the state is identified by the proximity switch) to the cylinder pin hole. At this time, the cylinder and the boom are directly rigidly locked. The intermediate state of the cylinder pin is the state where the cylinder pin is not fully extended (this state is not identified by the proximity switch).

[0039] Boom position detection: Detection strips are installed on both sides of the tail of each section of the telescopic boom, and proximity switches are fixedly installed on both sides of the telescopic cylinder head to form an arm position detection device to detect whether the arm position has been reached.

[0040] Arm pin detection: Detects whether the arm pin is fully extended or retracted.

[0041] Cylinder pin detection: Detect whether the cylinder pin is fully extended or retracted.

[0042] Cylinder length detection: detect the extended length of the telescopic cylinder.

[0043] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0044] Those skilled in the art will readily appreciate other embodiments of the invention after considering the specification and practicing the invention invented herein. This application is intended to cover any variations, uses or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art that are not invented by the present invention. The specification and examples are intended to be exemplary only, and the true scope and spirit of the invention are indicated by the claims.

[0045] Finally, a few points should be explained: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installed", "connected", "connected", and "matched" should be understood in a broad sense, which may refer to mechanical connection or electrical connection, or internal communication between two elements, or direct connection. "upper", "lower", "left", "right", etc. are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may change; Secondly: In the drawings of the embodiments of the present invention, only the structures involved in the embodiments of the present invention are involved, and other structures can refer to the general design; the above specific implementation methods further explain the purpose, technical solutions and beneficial effects of the present application in detail. It should be understood that the above are only specific implementation methods of the present application and are not used to limit the protection scope of the present application. Any modifications, equivalent substitutions, improvements, etc. made on the basis of the technical solutions of the present application should be included in the protection scope of the present application.

Claims

1. A crane telescopic system cylinder arm pin control device, characterized in that: It comprises a controller, an arm position detection device and a cylinder pin fixed point detection device, wherein the arm position detection device and the cylinder pin fixed point detection device are both mounted on the telescopic arm (7); The arm position detection device comprises a first proximity switch (1), a second proximity switch (2) and an arm position detection metal strip (12); the first proximity switch (1) and the second proximity switch (2) are mounted on a telescopic oil cylinder head (13); the arm position detection metal strip (12) is mounted on each boom section of the telescopic arm (7); and a controller is electrically connected to the first proximity switch (1) and the second proximity switch (2).

2. A crane telescopic system cylinder arm pin control device according to claim 1, characterized in that: It comprises a cylinder pin detection piece, which is installed at the arm tail of each boom section of the telescopic arm (7).

3. The crane telescopic system cylinder arm pin control device according to claim 1, characterized in that: The cylinder pin fixed-point detection device comprises a fixed-point release proximity switch (3), wherein the fixed-point release proximity switch (3) is installed between a first proximity switch (1) and a second proximity switch (2), and the fixed-point release proximity switch (3) is electrically connected to a controller.

4. The crane telescopic system cylinder arm pin control device according to claim 1, characterized in that: The cylinder pin fixed-point detection device comprises a fixed-point release cylinder pin detection metal strip (4) and a fourth proximity switch (5), wherein the fixed-point release cylinder pin detection metal strip (4) is mounted on each boom section of the telescopic arm (7), and the fourth proximity switch (5) is mounted on the other side of the cylinder pin (6), and the fourth proximity switch (5) is electrically connected to a controller.

5. A crane telescopic system cylinder arm pin control method, characterized in that: Based on the crane telescopic system cylinder arm pin control device according to any one of claims 1 to 4, the following steps are performed: Step 1, extending the boom of the telescopic arm (7); Step 2, determining whether the first proximity switch (1) or the second proximity switch (2) detects the arm position detection metal bar (12); if the first proximity switch (1) or the second proximity switch (2) detects the arm position detection metal bar (12), the boom of the telescopic arm (7) is extended at a first preset speed; Step 3, determining whether the fixed-point release proximity switch (3) or the fourth proximity switch (5) detects the fixed-point release cylinder pin detection metal strip (4); if the fixed-point release proximity switch (3) or the fourth proximity switch (5) detects the fixed-point release cylinder pin detection metal strip (4), the oil cylinder stops moving; Step 4, determining whether the fixed-point release proximity switch (3) or the fourth proximity switch (5) detects the fixed-point release cylinder pin detection metal strip (4); if the fixed-point release proximity switch (3) or the fourth proximity switch (5) detects the fixed-point release cylinder pin detection metal strip (4), the cylinder pin (6) is released and the telescopic arm (7) is locked.

6. A crane telescopic system cylinder arm pin control method according to claim 5, characterized in that: In step 2, if the first proximity switch (1) or the second proximity switch (2) does not detect the arm position detection metal strip (12), step 1 is executed.

7. A crane telescopic system cylinder arm pin control method according to claim 6, characterized in that: Step three, if the fixed-point release proximity switch (3) or the fourth proximity switch (5) does not detect the fixed-point release cylinder pin detection metal strip (4), the boom of the telescopic arm (7) is extended at a first preset speed, and this step is repeated.

8. The method for controlling the cylinder arm pin of a crane telescopic system according to claim 6, characterized in that: Step 4: If the fixed-point release proximity switch (3) or the fourth proximity switch (5) does not detect the fixed-point release cylinder pin detection metal strip (4), the telescopic arm (7) is extended in the reverse direction at a second preset speed, and this step is repeated.

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