Laser cutting method for beveling plastic pipes

Abstract

The invention discloses a laser cutting method for beveling of plastic pipes, and relates to the technical field of beveling cutting of plastic pipes. The laser cutting method comprises the following steps: clamping and lifting one end of the pipe by a clamping head, and supporting the other end of the pipe on a side support roller; adjusting the height of the bottom support roller; driving the internal pressure mechanism to translate into the inside of the pipe; adjusting the height of the bottom pressure roller of the internal pressure mechanism; adjusting the side pressure roller to press against the inner wall of the pipe; setting the data of the pulse adjustment module, and programming through the cutting trajectory control module of the laser cutter; moving the laser cutter; and spraying coolant to the cutting position during the cutting process. The advantages of the present invention are: the two ends of the pipe are respectively fixed by clamping and supporting, the pipe is not easy to bend and deform, the pipe will not shake during beveling cutting, and the cutting trajectory accuracy can be guaranteed; the debris generated during the cutting process is removed by spraying coolant, and the coolant can cool the pipe to avoid thermal damage to the pipe.

Description

Technical Field

[0001] The invention relates to the technical field of plastic pipe groove cutting, in particular to a laser cutting method for plastic pipe groove processing. Background Art

[0002] With the gradual development of laser cutting technology, the traditional manually controlled cutting position can no longer meet the demand. Currently, the emerging robot intelligent manufacturing technology is gradually combined with laser cutting to accurately cut the bevel of plastic pipes.

[0003] At present, before the laser cutting of the bevel of the pipe, the pipe will be clamped first, so that the position of the pipe is limited during the bevel cutting. However, in the prior art, the pipe is usually clamped at both ends or one end is clamped and the other end is supported. When the pipe is clamped at both ends, the pipe can only be subjected to the clamping force. When the pipe is long, it is easy to bend and deform. When one end is clamped and the other end is supported, the pipe is subjected to the bottom support force and is not easy to bend and deform. However, the end of the pipe is not fixed during the support. The pipe will shake to a certain extent during the bevel cutting. The cutting trajectory accuracy of the pipe is difficult to guarantee, which will result in low cutting accuracy and it is difficult to meet the requirements of the subsequent welding process. In addition, the pipe will produce slag and quickly generate heat during the laser bevel cutting process. The slag is usually removed by blowing auxiliary gas into the laser and material action area, but the cooling effect on the pipe is not significant. The heat will cause thermal damage to the pipe, change the microstructure of the pipe, and make the surface quality of the pipe poor. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a laser cutting method for beveling plastic pipes, which can solve the problems in the prior art of laser cutting the bevel of the pipe, such as the two ends of the pipe are clamped and fixed, the pipe is prone to bending deformation when it is long, one end of the pipe is clamped and the other end is used for bottom support, which causes a certain amount of shaking of the pipe when the pipe is cut, the accuracy of the cutting trajectory of the pipe is difficult to ensure, and the heat generated during the cutting of the pipe can cause thermal damage to the pipe, resulting in poor surface quality of the pipe.

[0005] In order to solve the above technical problems, the technical solution of the present invention is: comprising the following steps:

[0006] S1. Clamp one end of the pipe with the electric clamp on the clamping head, and drive the clamping head to rise and fall through the lifting seat, so as to drive the pipe to rise and fall to adjust the processing height of the pipe, so that the bottom of the other end of the pipe is supported on two symmetrically arranged side support rollers of the support mechanism;

[0007] S2. Adjust the height of the bottom support roller of the support mechanism to support the bottom of the other end of the pipe through the bottom support roller;

[0008] S3, driving the internal pressure mechanism to move horizontally to the inside of the other end of the pipe;

[0009] S4. Adjust the height of the bottom pressing roller of the internal pressure mechanism so that the bottom of the bottom pressing roller presses the inner bottom of the pipe. The bottom pressing roller and the bottom supporting roller correspond to the inner and outer sides of the bottom of the pipe and work together to press and fix the bottom of the pipe.

[0010] S5. Adjust the installation angles of the two side pressure rollers and the installation block of the internal pressure mechanism so that the two side pressure rollers correspond to the positions of the two side support rollers respectively, and adjust the positions of the side pressure rollers so that the side pressure rollers are against the inner wall of the pipe. The corresponding side pressure rollers and the side support rollers act on the same position of the pipe at the same time. The side pressure rollers and the side support rollers work together to press and fix the side lower part of the pipe, so that the pipe is supported and pressed and fixed at multiple points.

[0011] S6, connecting the pulse adjustment module of the laser cutter to the laser cutting head, setting the data of the pulse adjustment module by operating on the display end and sending corresponding instructions to the laser cutting head, and programming the cutting trajectory control module of the laser cutter to determine the groove cutting trajectory of the pipe;

[0012] S7, moving the laser cutter to the groove cutting position of the pipe, so that the laser cutting head is located at the initial cutting position of the groove cutting track, and the laser cutter drives the coolant injection mechanism to move simultaneously;

[0013] S8. The laser cutting head performs groove cutting on the pipe according to the groove cutting track of the pipe. During the cutting process, coolant is sprayed to the cutting position to clean up the debris generated by the cutting, and the pipe is cooled at the same time to prevent thermal damage to the pipe. The sprayed coolant is collected by a collection tank provided at the bottom of the pipe;

[0014] S9. After the laser cutting of the groove of the pipe is completed, the laser cutter is removed, the pressing and fixing of the end of the pipe is cancelled, the clamping of the end of the pipe is released, and the pipe is transported to the next processing step.

[0015] Furthermore, the cutting trajectory control module is implemented by ROBOTMASTER off-line programming software to control the cutting trajectory of the laser cutting head, and the pulse adjustment module is implemented by PLC to control the laser pulse period and laser pulse width of the laser cutting head.

[0016] Furthermore, the structure of the support mechanism is as follows: the support mechanism comprises a bottom support roller and a side support roller, the bottom support roller is driven to rise and fall by a lifting rod, and the side support rollers on both sides of the bottom support roller are fixedly arranged;

[0017] The structure of the internal pressure mechanism is as follows: the internal pressure mechanism comprises a bottom pressure roller and a side pressure roller, and the bottom pressure roller and the side pressure roller are respectively arranged corresponding to the bottom support roller and the side support roller;

[0018] The bottom pressure roller and the side pressure rollers are both driven by a telescopic mechanism to adjust their positions;

[0019] The bottom pressing roller and the side pressing roller are installed at the bottom of the moving frame, and the moving frame is driven to move in translation by a hydraulic cylinder.

[0020] Furthermore, the bottom support roller is sleeved on a first support shaft, and both ends of the first support shaft are respectively connected to the top of the lifting rod; the side support roller is sleeved on a second support shaft, and both ends of the second support shaft are respectively mounted and fixed on support columns.

[0021] Further, the telescopic mechanism comprises a first electric telescopic rod and a second electric telescopic rod;

[0022] The bottom pressure roller is sleeved on the first mounting shaft, the two ends of the first mounting shaft are fixed to the bottom of the first electric telescopic rod, the first electric telescopic rod is vertically mounted on the bottom of the bracket, the bracket is an inverted U-shaped structure, the bracket is fixedly connected to the bottom of the mobile frame, the mobile frame is an inverted L-shaped structure, one side of the mobile frame is fixedly connected to the top of the mobile column, and the mobile column is driven to translate by a hydraulic cylinder;

[0023] Inclined second electric telescopic rods are respectively arranged on both sides of the bracket, the side pressure rollers are sleeved on the second mounting shaft, and the two ends of the second mounting shaft are fixed to the bottom of the second electric telescopic rod.

[0024] Furthermore, the second electric telescopic rod is mounted on the side of the bracket through a mounting block, and the mounting block is a trapezoidal structure.

[0025] Furthermore, the second electric telescopic rod is rotatably connected to the mounting block via a pin shaft, and the second electric telescopic rod and the mounting block are locked via a bolt after rotation adjustment.

[0026] The advantages of the present invention are that the two ends of the pipe are fixed by clamping and supporting respectively, and the longer pipe is not easy to bend and deform when the groove is cut, and the position of the pipe is fixed, and the pipe will not shake during the groove cutting. The pipe is cut according to a pre-set cutting trajectory, which can ensure the accuracy of the cutting trajectory, and the cutting accuracy of the plastic pipe groove is improved to meet the requirements of the subsequent welding process.

[0027] The laser cutter drives the coolant injection mechanism to move simultaneously. The debris generated during the laser bevel cutting process of the pipe is removed by the injected coolant, and the coolant can cool down the heat generated during the pipe cutting. The pipe cooling effect is significant, avoiding thermal damage to the pipe and improving the surface quality of the pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1It is a schematic diagram of the mechanism structure for fixing the pipe cut by bevel laser according to the present invention;

[0029] Figure 2 This is a schematic diagram of the structure of the internal pressure mechanism for pressing and fixing the pipe in the present invention;

[0030] Figure 3 It is a side view of the supporting mechanism and internal pressure mechanism of the present invention supporting and pressing the pipe. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. The following embodiments can enable technicians in this field to understand the present invention more comprehensively, but the present invention is not limited to the scope of the embodiments.

[0032] This specific implementation adopts the following technical solutions: Figure 1-Figure 3 , the laser cutting method for plastic pipe beveling processing includes the following steps:

[0033] S1. Clamp one end of the pipe 10 by the electric clamp 11 on the clamping head 1, and drive the clamping head 1 to rise and fall by the lifting seat, thereby driving the pipe 10 to rise and fall to adjust the processing height of the pipe 10, so that the bottom of the other end of the pipe 10 is supported on two symmetrically arranged side support rollers 32 of the support mechanism 3.

[0034] S2. Adjust the height of the bottom support roller 31 of the support mechanism 3 to support the bottom of the other end of the pipe 10 through the bottom support roller 31.

[0035] S3, driving the internal pressure mechanism 4 to translate to the inside of the other end of the pipe 10, and the internal pressure mechanism 4 presses and fixes the pipe 10 inside the pipe 10.

[0036] S4. Adjust the height of the bottom pressing roller 41 of the internal pressure mechanism 4 so that the bottom of the bottom pressing roller 41 presses the inner bottom of the pipe 10. The bottom pressing roller 41 and the bottom supporting roller 31 correspond to the inner and outer sides of the bottom of the pipe 10, and work together to press and fix the bottom of the pipe 10.

[0037] S5. Adjust the installation angles of the two side pressing rollers 42 of the internal pressure mechanism 4 and the mounting block 15 so that the two side pressing rollers 42 correspond to the positions of the two side supporting rollers 32 respectively. Adjust the positions of the side pressing rollers 42 so that the side pressing rollers 42 press against the inner wall of the pipe 10. The corresponding side pressing rollers 42 and the side supporting rollers 32 act on the same position of the pipe 10 at the same time. The side pressing rollers 42 and the side supporting rollers 32 work together to press and fix the lower side of the pipe 10. The pipe 10 is supported and pressed and fixed at multiple points. The end of the pipe 10 can be effectively fixed. The pipe 10 will not shake or bend during groove cutting.

[0038] S6. Connect the pulse adjustment module of the laser cutter 16 to the laser cutting head, set the data of the pulse adjustment module by operating on the display end and send corresponding instructions to the laser cutting head. The pulse adjustment module is implemented by PLC and is used to control the laser pulse period and laser pulse width of the laser cutting head; program the cutting trajectory control module of the laser cutter 16 to determine the groove cutting trajectory of the pipe 10. The cutting trajectory control module is implemented by ROBOTMASTER offline programming software to control the cutting trajectory of the laser cutting head. The cutting trajectory control module and the pulse adjustment module can be directly set through the display device and then input into the laser cutter 16.

[0039] S7. Move the laser cutter 16 to the groove cutting position of the pipe 10 so that the laser cutting head is located at the initial cutting position of the groove cutting trajectory. The laser cutter 16 drives the coolant injection mechanism 17 to move at the same time. The injection pipe of the coolant injection mechanism 17 is fixed to the side of the laser cutter 16 through a fixed frame. When the laser cutter 16 moves along the frame, it drives the injection pipe of the coolant injection mechanism 17 to move horizontally at the same time. The injection pipe is tilted toward the laser cutting head. A nozzle is installed at one end of the injection pipe, and the other end of the injection pipe is connected to a liquid pump. The liquid pump is arranged in a coolant storage barrel.

[0040] S8. The laser cutting head performs bevel cutting on the pipe 10 according to the bevel cutting trajectory of the pipe 10. During the cutting process, the spray pipe sprays coolant to the cutting position of the pipe 10 to clean up the debris generated by the cutting, and cools the pipe 10 at the same time to prevent thermal damage to the pipe 10. The sprayed coolant is collected by a collection tank provided at the bottom of the pipe 10, and the collection tank is not shown in the figure.

[0041] S9. After the laser cutting of the groove of the tube 10 is completed, the laser cutter 16 is removed, the pressing and fixing of the end of the tube 10 is cancelled, the clamping of the end of the tube 10 is released, and the tube 10 is transported to the next processing step.

[0042] like Figure 1-Figure 3As shown, the installation structure of the clamping head 1 used in the above method is: the clamping head 1 is installed on one side of the mounting seat 2, and the mounting seat 2 is installed on the base. Six electric clamping claws 11 are evenly arranged on the side of the clamping head 1 away from the mounting seat 2. An electric slider is arranged in the clamping head 1, which is not shown in the figure. The six electric clamping claws 11 can be controlled to move synchronously respectively. The six electric clamping claws 11 are respectively in contact with the outer periphery of the pipe 10, so that the end of the pipe 10 can be effectively clamped and fixed, and pipes 10 of different specifications can be clamped. A lifting seat is installed in the mounting seat 2, which is not shown in the figure. The side of the clamping head 1 close to the mounting seat 2 is installed on the lifting seat through a fixed block. The side of the mounting seat 2 is provided with a vertical moving groove for moving the fixed block. The lifting seat can drive the clamping head 1 to rise and fall to adjust the height. The specific structure and principle of the electric clamping claws 11 and the lifting seat are the existing technology well known to those skilled in the art and will not be elaborated.

[0043] The structure of the support mechanism 3 is as follows: the support mechanism 3 has a bottom support roller 31 and a side support roller 32, the bottom support roller 31 and the side support roller 32 respectively support the bottom and the lower outer side of the pipe 10, the bottom support roller 31 is sleeved on the first support shaft 33, the two ends of the first support shaft 33 are respectively connected to the upper part of the lifting rod 5, the bottom support roller 31 is driven to rise and fall by the lifting rod 5 to achieve height adjustment, when supporting pipes 10 of different specifications, the bottom position of the pipe 10 will change, and the bottom support roller 31 can be adjusted in height accordingly.

[0044] The side support rollers 32 are sleeved on the second support shaft 34, and the two ends of the second support shaft 34 are respectively mounted and fixed on the support column 6. The height of the support column 6 is fixed, and the side support rollers 32 on both sides are fixedly arranged. There is no need to adjust the height during support. The side support rollers 32 on both sides can support pipes 10 of different specifications. The bottom support rollers 31 can be adjusted according to the bottom height of the pipe 10 to provide multi-point support for the pipe 10.

[0045] The structure of the internal pressure mechanism 4 is as follows: the internal pressure mechanism 4 has a bottom pressing roller 41 and a side pressing roller 42, the bottom pressing roller 41 and the side pressing roller 42 respectively press the inner bottom and the inner lower side of the tube 10, and the bottom pressing roller 41 and the side pressing roller 42 are respectively arranged corresponding to the bottom support roller 31 and the side support roller 32.

[0046] The bottom pressure roller 41 and the side pressure roller 42 are both driven by a telescopic mechanism for position adjustment. The telescopic mechanism includes a first electric telescopic rod 7 and a second electric telescopic rod 8. The first electric telescopic rod 7 and the second electric telescopic rod 8 respectively drive the bottom pressure roller 41 and the side pressure roller 42 for position adjustment.

[0047] The installation structure of the bottom pressure roller 41 and the side pressure roller 42 is as follows: the bottom pressure roller 41 is sleeved on the first installation shaft 43, and the two ends of the first installation shaft 43 are fixed to the bottom of the first electric telescopic rod 7. The first electric telescopic rod 7 is vertically installed at the bottom of the bracket 9. The bracket 9 is an inverted U-shaped structure. The bottom pressure roller 41 and the side pressure roller 42 can enter the interior of the pipe 10. The bottom pressure roller 41 presses the inner bottom of the pipe 10 to fix the pipe 10. When the pipes 10 of different specifications are fixed, the height of the bottom support roller 31 is adjusted accordingly. Similarly, the bottom pressure roller 41 is also adjusted in height accordingly through the drive of the first electric telescopic rod 7, so that the bottom pressure roller 41 and the bottom support roller 31 are in contact with the outer bottom and inner bottom of the pipe 10, and work together to support and press the bottom of the pipe 10 to fix it.

[0048] An inclined second electric telescopic rod 8 is provided on both sides of the bracket 9, and a side pressure roller 42 is sleeved on the second mounting shaft 44. Both ends of the second mounting shaft 44 are fixed to the bottom of the second electric telescopic rod 8. The second electric telescopic rod 8 is installed on the side of the bracket 9. The extension and retraction of the second electric telescopic rod 8 can drive the side pressure roller 42 to adjust the position to adapt to pipes 10 of different specifications. After adjustment, the side pressure roller 42 presses the inner lower side of the pipe 10. The side pressure roller 42 and the side support roller 32 press and support the pipe 10 from the inside and outside of the pipe 10 respectively, so as to realize multi-point support and pressing of the pipe 10, and the fixing effect of the end of the pipe 10 is good.

[0049] The bracket 9 is fixedly connected to the bottom of the mobile frame 12. The mobile frame 12 is an inverted L-shaped structure. One side of the mobile frame 12 is fixedly connected to the top of the mobile column 13. The mobile column 13 is driven to translate by the hydraulic cylinder 14. The movement of the mobile column 13 can drive the mobile frame 12 to translate. The mobile frame 12 drives the bracket 9 and the bottom pressure roller 41 and the side pressure roller 42 to move toward the pipe 10 and enter the interior of the pipe 10. The distance from the top of the mobile frame 12 to the bottom of the bottom pressure roller 41 is less than the diameter of the pipe 10.

[0050] The second electric telescopic rod 8 is installed on the side of the bracket 9 through the mounting block 15. The mounting block 15 is a trapezoidal structure. The second electric telescopic rod 8 and the mounting block 15 are rotatably connected through a pin shaft. The second electric telescopic rod 8 and the mounting block 15 are locked by bolts after rotation adjustment.

[0051] The angle between the second electric telescopic rod 8 and the mounting block 15 is adjustable, and the pressing point of the side pressing roller 42 on the pipe 10 can be changed accordingly with the supporting point of the side supporting roller 32 on the pipe 10, so that the pressing and supporting points of the side pressing roller 42 and the side supporting roller 32 on the pipe 10 are the same point on the pipe 10, that is, the supporting pressing point of the pipe 10 is just located between the side pressing roller 42 and the side supporting roller 32, which has a better fixing effect on the pipe 10, and pipes 10 of different specifications can be well fixed when cut.

[0052] The electric clamp 11, lifting rod 5, first electric telescopic rod 7, second electric telescopic rod 8, hydraulic cylinder 14 and other components described above are all universal standard parts or components known to those skilled in the art. Their structures and principles can be known to those skilled in the art through technical manuals or through conventional experimental methods and will not be elaborated on.

[0053] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A laser cutting method for beveling plastic pipes, characterized in that: A pipe cutting and clamping machine is used to assist the cutting process. The pipe cutting and clamping machine includes a clamping head, a supporting mechanism and an internal pressure mechanism; The structure of the support mechanism is as follows: the support mechanism comprises a bottom support roller and a side support roller, the bottom support roller is driven to rise and fall by a lifting rod, and the side support rollers on both sides of the bottom support roller are fixedly arranged; The structure of the internal pressure mechanism is as follows: the internal pressure mechanism comprises a bottom pressure roller and a side pressure roller, and the bottom pressure roller and the side pressure roller are respectively arranged corresponding to the bottom support roller and the side support roller; The bottom pressure roller and the side pressure rollers are both driven by a telescopic mechanism to adjust their positions; The bottom pressure roller and the side pressure roller are installed at the bottom of the moving frame, and the moving frame is driven to move in translation by a hydraulic cylinder; The bottom support roller is sleeved on the first support shaft, and the two ends of the first support shaft are respectively connected to the upper part of the lifting rod; the side support roller is sleeved on the second support shaft, and the two ends of the second support shaft are respectively mounted and fixed on the support column; The telescopic mechanism comprises a first electric telescopic rod and a second electric telescopic rod; The bottom pressure roller is sleeved on the first mounting shaft, the two ends of the first mounting shaft are fixed to the bottom of the first electric telescopic rod, the first electric telescopic rod is vertically mounted on the bottom of the bracket, the bracket is an inverted U-shaped structure, the bracket is fixedly connected to the bottom of the mobile frame, the mobile frame is an inverted L-shaped structure, one side of the mobile frame is fixedly connected to the top of the mobile column, and the mobile column is driven to translate by a hydraulic cylinder; The two sides of the bracket are respectively provided with inclined second electric telescopic rods, the side pressure rollers are sleeved on the second mounting shaft, and the two ends of the second mounting shaft are fixed to the bottom of the second electric telescopic rod; The laser cutting method includes the following steps: S1. Clamp one end of the pipe with the electric clamp on the clamping head, and drive the clamping head to rise and fall through the lifting seat, so as to drive the pipe to rise and fall to adjust the processing height of the pipe, so that the bottom of the other end of the pipe is supported on two symmetrically arranged side support rollers of the support mechanism; S2. Adjust the height of the bottom support roller of the support mechanism to support the bottom of the other end of the pipe through the bottom support roller; S3, driving the internal pressure mechanism to move horizontally to the inside of the other end of the pipe; S4. Adjust the height of the bottom pressing roller of the internal pressure mechanism so that the bottom of the bottom pressing roller presses the inner bottom of the pipe. The bottom pressing roller and the bottom supporting roller correspond to the inner and outer sides of the bottom of the pipe and work together to press and fix the bottom of the pipe. S5. Adjust the installation angles of the two side pressure rollers and the installation block of the internal pressure mechanism so that the two side pressure rollers correspond to the positions of the two side support rollers respectively, and adjust the positions of the side pressure rollers so that the side pressure rollers are against the inner wall of the pipe. The corresponding side pressure rollers and the side support rollers act on the same position of the pipe at the same time. The side pressure rollers and the side support rollers work together to press and fix the side and lower part of the pipe, so that the pipe is supported and pressed and fixed at multiple points. S6, connecting the pulse adjustment module of the laser cutter to the laser cutting head, setting the data of the pulse adjustment module by operating on the display end and sending corresponding instructions to the laser cutting head, and programming the cutting trajectory control module of the laser cutter to determine the groove cutting trajectory of the pipe; S7, moving the laser cutter to the groove cutting position of the pipe, so that the laser cutting head is located at the initial cutting position of the groove cutting track, and the laser cutter drives the coolant injection mechanism to move simultaneously; S8. The laser cutting head performs groove cutting on the pipe according to the groove cutting track of the pipe. During the cutting process, coolant is sprayed to the cutting position to clean up the debris generated by the cutting, and the pipe is cooled at the same time to prevent thermal damage to the pipe. The sprayed coolant is collected by a collection tank provided at the bottom of the pipe; S9. After the laser cutting of the groove of the pipe is completed, the laser cutter is removed, the pressing and fixing of the end of the pipe is cancelled, the clamping of the end of the pipe is released, and the pipe is transported to the next processing step.

2. The laser cutting method for beveling plastic pipes according to claim 1, characterized in that: The cutting trajectory control module is implemented by ROBOTMASTER off-line programming software and is used to control the cutting trajectory of the laser cutting head. The pulse adjustment module is implemented by PLC and is used to control the laser pulse period and laser pulse width of the laser cutting head.

3. The laser cutting method for beveling plastic pipes according to claim 1, characterized in that: The second electric telescopic rod is installed on the side of the bracket through a mounting block, and the mounting block is a trapezoidal structure.

4. The laser cutting method for beveling plastic pipes according to claim 1, characterized in that: The second electric telescopic rod is rotatably connected to the mounting block via a pin shaft, and the second electric telescopic rod and the mounting block are locked via a bolt after rotation adjustment.

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