Overload protection device of crane

Abstract

The invention relates to the technical field of crane maintenance equipment, and particularly discloses a crane overload protection device which comprises a base fixedly mounted at the top of a standard knot, a disc-shaped mounting table is arranged above the base, and a crane is fixedly mounted on the upper surface of the mounting table. The reinforcing mechanism is fixedly mounted in the base; and the auxiliary mechanism is fixedly mounted in the reinforcing mechanism. Through cooperation of a bearing ring and a rotating column, a rotating cover can rotate in the downward moving process, and meanwhile three rotating discs fixedly connected with a supporting column are arranged, so that the rotating discs synchronously rotate on a stable disc along with rotation of the rotating cover; through the double-layer stable structure, the gravity center of the crane is always kept vertical during working, so that the working stability of the crane is greatly improved, and the safety of a working environment is effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of crane maintenance equipment, in particular to an overload protection device for a crane. Background Art

[0002] In the field of lifting machinery, overload protection devices are core equipment to ensure the safe operation of cranes. Its main function is to monitor the load status of the crane in real time, trigger the protection mechanism when overloaded, and prevent safety hazards such as structural damage and overturning accidents caused by overload. This device is widely used in construction, logistics and warehousing, etc. It uses mechanical, electronic or hydraulic technical means to dynamically monitor the lifting capacity, center of gravity balance and other parameters of the crane to ensure that the operation process complies with safety regulations, which is of great significance to protecting personnel life safety and reducing economic losses.

[0003] Traditional crane overload protection devices have significant defects. In terms of stability control, most devices rely on a single support structure, which makes it difficult to cope with the problem of center of gravity offset under complex working conditions, causing the crane to easily tilt or overturn during operation, especially when lifting heavy goods or turning at high speed, the safety risk increases significantly. The monitoring and early warning mechanism is imperfect. Some equipment only uses simple weight sensors for overload alarms. There is a lack of real-time dynamic center of gravity balance monitoring and visual prompts, making it difficult to accurately judge the degree of overload and potential risks. In addition, traditional devices lack intelligent active protection capabilities. When overload occurs, they cannot automatically limit dangerous operations of the crane (such as turning), and still rely on manual intervention. The response speed is slow and accidents are prone to human errors. The adaptability and reliability of the equipment are insufficient, and it is difficult to adapt to the structural differences of different types of cranes. After long-term use, mechanical wear or sensor failure is prone to occur, and the maintenance cost is high. It cannot meet the needs of modern engineering for efficient and safe lifting operations. Summary of the invention

[0004] 1. Technical issues to be resolved The present invention provides an overload protection device for a crane, which solves the problems mentioned in the above background technology.

[0005] (II) Technical solution To achieve the above objectives, the present invention is implemented through the following technical solutions: an overload protection device for a crane, comprising a base, the base is fixedly mounted on the top of a standard section, a mounting platform is arranged above the base, wherein the mounting platform is arranged in a disc shape, and the crane is fixedly mounted on the upper surface of the mounting platform, and further comprising: A reinforcing mechanism, wherein the reinforcing mechanism is fixedly mounted inside the base; An auxiliary mechanism, wherein the auxiliary mechanism is fixedly installed inside the reinforcing mechanism; The reinforcing mechanism comprises a No. 1 slide groove, which is opened at the bottom of the base, a rotating cover is slidably engaged on the upper part of the No. 1 slide groove, a carrying ring is pressed and fitted on the bottom surface of the rotating cover, a telescopic rod is fixedly connected to the bottom surface of the carrying ring, the bottom of the telescopic rod is fixedly embedded in the bottom of the No. 1 slide groove, four telescopic rods are arranged at fixed intervals around the central axis of the carrying ring, a rotating column is rotatably connected to the side surface of the rotating cover, a rotating shaft is slidably connected to the inside of the rotating column, the rotating shaft passes through and is rotatably connected to the bottom of the base, and the rotating shaft is driven to rotate by a motor.

[0006] Preferably, a support column is fixedly connected to the middle upper surface of the rotating cover, the top of the support column is fixedly connected to the bottom surface of the mounting platform, and a second slide groove is opened inside the base, and the second slide groove is arranged above the first slide groove.

[0007] Preferably, a sliding ring is slidably connected up and down inside the No. 2 slide groove, a stabilizing disk is fixedly connected to the inner surface of the sliding ring, three stabilizing disks are arranged at fixed intervals along the inner surface of the sliding ring, and the stabilizing disk is slidably sleeved on the outer surface of the support column.

[0008] Preferably, a rotating roller is rotatably connected to the upper surface of the stabilizing disk, and six rotating rollers are arranged at fixed intervals along the central axis of the same stabilizing disk. A rotating disk is fitted on the upper surface of the rotating roller, and the rotating disk is fixedly sleeved on the outer surface of the supporting column. The outer surface of the rotating roller is evenly and fixedly connected with a plug-in strip in an annular shape, and the bottom surface of the rotating disk is evenly and annularly provided with plug-in grooves, and the plug-in strips are plugged into the plug-in grooves.

[0009] Preferably, the auxiliary mechanism includes a connecting groove, the connecting groove is opened through the bottom of the supporting column, the interior of the supporting column is configured to be hollow, and the connecting groove is arranged at the bottom of the No. 2 slide groove.

[0010] Preferably, a mounting groove is provided inside the mounting platform, the mounting groove is arranged in a circular shape, a connecting pipe is fixedly connected through the middle bottom surface of the mounting groove, a baffle is fixedly connected to the outer surface of the connecting pipe, and the end of the baffle away from the connecting pipe is fixedly connected to the inner surface of the mounting groove.

[0011] Preferably, an elastic connecting rod is fixedly connected to the outer surface of the baffle bar, an end of the elastic connecting rod away from the baffle bar is fixedly connected to a rotating plate, an inner end of the rotating plate is rotatably connected to the outer surface of the connecting tube, a through hole is penetrated through the outer surface of the connecting tube close to the elastic connecting rod, a reminder window is penetrated through the side surface of the mounting platform, and a reminder sticker is posted on the side surface of the rotating plate.

[0012] Preferably, an auxiliary groove is provided on the upper surface of the support column, and the auxiliary groove is arranged in a tubular shape. A connecting port is provided on the bottom surface of the mounting platform, and the mounting groove and the auxiliary groove are connected through the connecting port, wherein the connecting port is arranged on the opposite side of the elastic connecting rod.

[0013] Preferably, a driving groove is provided on the inner side of the stabilizing plate, the driving groove is connected with the auxiliary groove, and a No. 1 plug-in rod is slidably connected to the inside of the driving groove, and the No. 1 plug-in rod is arranged on the inner side of the rotating roller, and a No. 2 plug-in rod is elastically slidably plugged with the two ends of the No. 1 plug-in rod, and the No. 2 plug-in rod and the No. 1 plug-in rod are combined into a circular ring shape, and a locking rod is fixedly connected to the surface of the No. 1 plug-in rod close to the rotating roller, wherein the locking rod and the rotating roller can be engaged with each other, and the device can be installed as a whole on the top of the standard section, and then the crane is installed on the upper surface of the mounting platform. Under normal conditions, when the crane lifts the cargo, the motor is started to drive the rotating shaft to work, and the rotating cover can be driven to rotate through the rotating shaft and the rotating column, and then the mounting platform is driven to rotate through the supporting column, thereby realizing the steering operation of the crane, and when the crane lifts the cargo, the gravity will increase, and then the downward extrusion force on the mounting platform will be greatly increased, that is, the rotating cover is squeezed by the supporting column to move downward in the No. 1 slide groove.

[0014] (III) Beneficial effects The present invention provides an overload protection device for a crane, which has the following beneficial effects: (I) The overload protection device of the crane can rotate the rotating cover during the downward movement through the cooperation of the load ring and the rotating column. At the same time, three rotating disks fixedly connected to the support column are arranged so that the rotating disks rotate synchronously on the stabilizing disk as the rotating cover rotates. The double-level stabilizing structure allows the center of gravity of the crane to always remain vertical during operation, which greatly improves the stability of the crane during operation and effectively improves the safety of the working environment.

[0015] (ii) The overload protection device of the crane increases with the increase of the cargo lifted by the crane, and the downward pressure on the mounting platform will further increase, thereby further increasing the downward distance of the rotating cover in the No. 1 slide groove, and synchronously driving the sliding ring to move downward in the No. 2 slide groove, that is, the cavity at the bottom of the No. 2 slide groove is squeezed by the stabilizing plate, so that the air pressure at the bottom of the No. 2 slide groove is input into the interior of the supporting column through the connecting groove, and then input into the mounting groove on one side of the elastic connecting rod through the connecting pipe through the top of the supporting column. Under the action of the air pressure, the rotating plate begins to slide along the mounting groove, so that the reminder sticker posted on the side surface of the rotating plate is displayed to the outside through the reminder window, so that the staff can always check whether the weight of the cargo lifted by the crane meets the lifting standards, thereby improving the purpose of standardized operation on the construction site, and can also remind outside staff when the crane is overloaded to avoid safety hazards.

[0016] (III) The overload protection device of the crane is designed such that if the crane is overloaded and the rotation angle of the rotating plate reaches the maximum value, the connecting port at the bottom of the mounting platform will be opened. At this time, the air pressure in the mounting slot will enter the auxiliary slot of the support column through the connecting port, and then enter the driving slot through the auxiliary slot. Under the action of pressure, the No. 1 plug-in rod and the No. 2 plug-in rod will be pushed to expand outward, so that the locking rod on the outer surface of the No. 1 plug-in rod will be connected with the rotating roller, and the rotating roller will be fixed so that it cannot continue to rotate, thereby locking the rotating disk, so that the steering function of the crane is automatically locked when the crane is overloaded, avoiding the problem of safety hazards caused by the continued operation of the crane. After the safety hazard is eliminated, the air pressure in the auxiliary slot only needs to be released to allow the equipment to continue working. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 It is a schematic diagram of the internal structure of the base of the present invention; Figure 3 It is a structural schematic diagram of the carrier ring of the present invention; Figure 4 It is a structural schematic diagram of the rotating column of the present invention; Figure 5 It is a structural schematic diagram of the rotating disk of the present invention; Figure 6 It is a structural schematic diagram of the support column of the present invention; Figure 7 It is a schematic diagram of the structure of the driving slot of the present invention; Figure 8 It is a schematic diagram of the internal structure of the mounting platform of the present invention.

[0018] In the figure: 1. base; 2. mounting table; 3. reinforcing mechanism; 31. slide slot No. 1; 32. rotating cover; 33. bearing ring; 34. telescopic rod; 35. rotating column; 36. rotating shaft; 37. supporting column; 38. slide slot No. 2; 39. sliding ring; 310. stabilizing disk; 311. rotating roller; 312. rotating disk; 313. plug-in strip; 314. plug-in slot; 4. auxiliary mechanism; 41. connecting slot; 42. mounting slot; 43. connecting pipe; 44. blocking strip; 45. elastic connecting rod; 46. rotating plate; 47. prompt window; 48. auxiliary slot; 49. driving slot; 410. plug-in rod No. 1; 411. plug-in rod No. 2; 412. locking rod. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] First embodiment: Figures 1 to 8 As shown, the present invention provides a technical solution: an overload protection device for a crane, comprising a base 1, the base 1 is fixedly mounted on the top of a standard section, a mounting platform 2 is arranged above the base 1, wherein the mounting platform 2 is arranged in a disc shape, and the crane is fixedly mounted on the upper surface of the mounting platform 2, and further comprising: A reinforcing mechanism 3, wherein the reinforcing mechanism 3 is fixedly mounted inside the base 1; Auxiliary mechanism 4, the auxiliary mechanism 4 is fixedly installed inside the reinforcing mechanism 3; The reinforcing mechanism 3 includes a No. 1 slide groove 31, which is opened at the bottom of the base 1, and a rotating cover 32 is slidably engaged on the upper part of the No. 1 slide groove 31, and a carrying ring 33 is pressed and fitted on the bottom surface of the rotating cover 32, and a telescopic rod 34 is fixedly connected to the bottom surface of the carrying ring 33, and the bottom of the telescopic rod 34 is fixedly embedded in the bottom of the No. 1 slide groove 31, wherein four telescopic rods 34 are arranged at fixed intervals around the central axis of the carrying ring 33, and a rotating column 35 is rotatably connected to the side surface of the rotating cover 32, and a rotating shaft 36 is slidably connected to the inside of the rotating column 35, and the rotating shaft 36 passes through and is rotatably connected to the bottom of the base 1, wherein the rotating shaft 36 is driven to rotate by a motor.

[0021] A support column 37 is fixedly connected to the middle upper surface of the rotating cover 32 , and the top of the support column 37 is fixedly connected to the bottom surface of the mounting platform 2 . A second slide groove 38 is opened inside the base 1 , and the second slide groove 38 is arranged above the first slide groove 31 .

[0022] A sliding ring 39 is slidably connected to the interior of the No. 2 slide groove 38, and a stabilizing disk 310 is fixedly connected to the inner surface of the sliding ring 39. Three stabilizing disks 310 are arranged at fixed intervals along the inner surface of the sliding ring 39, and the stabilizing disks 310 are slidably sleeved on the outer surface of the support column 37.

[0023] The upper surface of the stabilizing disk 310 is rotatably connected to a rotating roller 311. Six rotating rollers 311 are arranged at fixed intervals along the central axis of the same stabilizing disk 310. A rotating disk 312 is fitted on the upper surface of the rotating roller 311. The rotating disk 312 is fixedly sleeved on the outer surface of the support column 37. The outer surface of the rotating roller 311 is evenly and fixedly connected to a plug-in strip 313 in an annular shape. The bottom surface of the rotating disk 312 is evenly and annularly provided with plug-in grooves 314, and the plug-in strips 313 are plugged into the plug-in grooves 314.

[0024] Second embodiment: Figures 1 to 8 As shown, the auxiliary mechanism 4 includes a connecting groove 41 , which is opened through the bottom of the support column 37 , the interior of the support column 37 is configured to be hollow, and the connecting groove 41 is arranged at the bottom of the No. 2 slide groove 38 .

[0025] An installation groove 42 is provided inside the installation platform 2. The installation groove 42 is set to be circular. A connecting pipe 43 is fixedly connected to the middle bottom surface of the installation groove 42. A retaining bar 44 is fixedly connected to the outer surface of the connecting pipe 43. The end of the retaining bar 44 away from the connecting pipe 43 is fixedly connected to the inner surface of the installation groove 42.

[0026] An elastic connecting rod 45 is fixedly connected to the outer surface of the baffle bar 44, and a rotating plate 46 is fixedly connected to the end of the elastic connecting rod 45 away from the baffle bar 44. The inner end of the rotating plate 46 is rotatably connected to the outer surface of the connecting tube 43. A through hole is penetrated through the outer surface of the connecting tube 43 on the side close to the elastic connecting rod 45, a reminder window 47 is penetrated through the side surface of the mounting platform 2, and a reminder sticker is posted on the side surface of the rotating plate 46.

[0027] An auxiliary groove 48 is provided on the upper surface of the support column 37 , and the auxiliary groove 48 is arranged in a tubular shape. A connecting port is provided on the bottom surface of the mounting platform 2 , and the mounting groove 42 is connected to the auxiliary groove 48 through the connecting port, wherein the connecting port is arranged on the opposite side of the elastic connecting rod 45 .

[0028] A driving groove 49 is provided on the inner side of the stabilizing disk 310, and the driving groove 49 is connected to the auxiliary groove 48. A No. 1 plug-in rod 410 is slidably connected inside the driving groove 49. The No. 1 plug-in rod 410 is arranged just inside the rotating roller 311. A No. 2 plug-in rod 411 is elastically slidably connected to both ends of the No. 1 plug-in rod 410. The No. 2 plug-in rod 411 and the No. 1 plug-in rod 410 are combined into a circular ring shape. A locking rod 412 is fixedly connected to the surface of the No. 1 plug-in rod 410 close to the rotating roller 311, and the locking rod 412 and the rotating roller 311 can be clamped with each other.

[0029] When working, the device can be installed as a whole on the top of the standard section, and then the crane is installed on the upper surface of the mounting platform 2. Under normal conditions, when the crane lifts goods, the motor is started to drive the rotating shaft 36 to work, and the rotating cover 32 can be driven to rotate through the rotating shaft 36 and the rotating column 35, and then the mounting platform 2 can be driven to rotate through the supporting column 37, so as to realize the steering operation of the crane. When the crane lifts the goods, the gravity will increase, and then the downward squeezing force on the mounting platform 2 will be greatly increased, that is, the rotating cover 32 is squeezed by the supporting column 37 to move downward in the No. 1 slide groove 31, and the rotating cover 32 can also rotate during the downward movement process through the cooperation of the carrying ring 33 and the rotating column 35. At the same time, by setting The three rotating disks 312 fixedly connected to the column 37 allow the rotating disk 312 to rotate synchronously on the stabilizing disk 310 as the rotating cover 32 rotates. The double-level stabilizing structure allows the center of gravity of the crane to always remain vertical during operation, greatly improving the stability of the crane during operation and effectively improving the safety of the working environment. As the amount of cargo lifted by the crane increases, the downward pressure on the mounting platform 2 will further increase, thereby further increasing the downward distance of the rotating cover 32 in the No. 1 slide groove 31, and synchronously driving the sliding ring 39 to move downward in the No. 2 slide groove 38, that is, the cavity at the bottom of the No. 2 slide groove 38 is squeezed by the stabilizing disk 310, causing the air pressure at the bottom of the No. 2 slide groove 38 to pass through the connecting groove 41 is input into the interior of the support column 37, and is input into the installation groove 42 on one side of the elastic connecting rod 45 through the top of the support column 37 through the connecting pipe 43. Under the action of air pressure, the rotating plate 46 begins to slide along the installation groove 42, so that the reminder sticker posted on the side surface of the rotating plate 46 is displayed to the outside through the reminder window 47, so that the staff can always check whether the weight of the goods lifted by the crane meets the lifting standards, thereby improving the purpose of standardized operation on the construction site, and can also remind outside staff when the crane is overloaded to avoid safety hazards. If the crane is overloaded, the rotation angle of the rotating plate 46 reaches the maximum value, and the connecting port at the bottom of the mounting platform 2 is about to be opened. At this time The air pressure in the mounting groove 42 will enter the auxiliary groove 48 of the support column 37 through the connecting port, and enter the driving groove 49 through the auxiliary groove 48, and begin to push the No. 1 plug-in rod 410 and the No. 2 plug-in rod 411 to expand outward under the action of pressure, that is, finally the locking rod 412 on the outer surface of the No. 1 plug-in rod 410 is connected with the rotating roller 311, and the rotating roller 311 is fixed so that it cannot continue to rotate, and then the rotating disk 312 is locked, so that the steering function of the crane is automatically locked when the crane is overloaded, so as to avoid the problem of safety hazards caused by the continued operation of the crane. After the safety hazard is avoided, the air pressure in the auxiliary groove 48 only needs to be released to allow the equipment to continue working.

[0030] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0031] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An overload protection device for a crane, comprising a base (1), characterized in that: The base (1) is fixedly mounted on the top of the standard section, a mounting platform (2) is arranged above the base (1), and further comprises: A reinforcing mechanism (3), wherein the reinforcing mechanism (3) is fixedly mounted inside the base (1); An auxiliary mechanism (4), wherein the auxiliary mechanism (4) is fixedly installed inside the reinforcing mechanism (3); The reinforcing mechanism (3) comprises a No. 1 slide groove (31), wherein the No. 1 slide groove (31) is provided at the bottom of the base (1), a rotating cover (32) is slidably engaged on the upper part of the No. 1 slide groove (31), a bearing ring (33) is pressed and fitted on the bottom surface of the rotating cover (32), a telescopic rod (34) is fixedly connected to the bottom surface of the bearing ring (33), the bottom of the telescopic rod (34) is fixedly embedded in the bottom of the No. 1 slide groove (31), a rotating column (35) is rotatably connected to the side surface of the rotating cover (32), a rotating shaft (36) is slidably connected to the inside of the rotating column (35), and the rotating shaft (36) is rotatably connected to the bottom of the base (1).

2. The overload protection device for a crane according to claim 1, characterized in that: A support column (37) is fixedly connected to the middle upper surface of the rotating cover (32), and the top of the support column (37) is fixedly connected to the bottom surface of the mounting platform (2). A second slide groove (38) is provided inside the base (1), and the second slide groove (38) is arranged above the first slide groove (31).

3. The overload protection device for a crane according to claim 2, characterized in that: A sliding ring (39) is slidably connected to the interior of the second slide groove (38) in an upward and downward manner, and a stabilizing disk (310) is fixedly connected to the inner surface of the sliding ring (39). Three stabilizing disks (310) are arranged at fixed intervals along the inner surface of the sliding ring (39), and the stabilizing disks (310) are slidably sleeved on the outer surface of the support column (37).

4. The overload protection device for a crane according to claim 3, characterized in that: The upper surface of the stabilizing disk (310) is rotatably connected to a rotating roller (311), six rotating rollers (311) are arranged at fixed intervals along the central axis of the same stabilizing disk (310), a rotating disk (312) is fitted on the upper surface of the rotating roller (311), the rotating disk (312) is fixedly sleeved on the outer surface of the support column (37), the outer surface of the rotating roller (311) is evenly and fixedly connected to a plug-in strip (313) in an annular shape, the bottom surface of the rotating disk (312) is evenly and annularly provided with plug-in grooves (314), and the plug-in strips (313) are plugged into the plug-in grooves (314).

5. The overload protection device for a crane according to claim 4, characterized in that: The auxiliary mechanism (4) comprises a connecting groove (41), the connecting groove (41) is opened through the bottom of the support column (37), the interior of the support column (37) is arranged to be hollow, and the connecting groove (41) is arranged at the bottom of the second slide groove (38).

6. The overload protection device for a crane according to claim 5, characterized in that: A mounting groove (42) is provided inside the mounting platform (2), the mounting groove (42) being arranged in a circular shape, a connecting pipe (43) passing through and fixedly connected to the middle bottom surface of the mounting groove (42), a retaining bar (44) being fixedly connected to the outer surface of the connecting pipe (43), and an end of the retaining bar (44) away from the connecting pipe (43) being fixedly connected to the inner surface of the mounting groove (42).

7. The overload protection device for a crane according to claim 6, characterized in that: The outer surface of the baffle (44) is fixedly connected to an elastic connecting rod (45), one end of the elastic connecting rod (45) away from the baffle (44) is fixedly connected to a rotating plate (46), the inner end of the rotating plate (46) is rotatably connected to the outer surface of the connecting tube (43), a through hole is penetrated through the outer surface of the connecting tube (43) on the side close to the elastic connecting rod (45), a prompt window (47) is penetrated through the side surface of the mounting platform (2), and a prompt sticker is posted on the side surface of the rotating plate (46).

8. The overload protection device for a crane according to claim 7, characterized in that: An auxiliary groove (48) is provided on the upper surface of the support column (37), and the auxiliary groove (48) is arranged in a tubular shape. A communication port is provided on the bottom surface of the mounting platform (2), and the mounting groove (42) is connected to the auxiliary groove (48) through the communication port.

9. The overload protection device for a crane according to claim 8, characterized in that: A driving groove (49) is formed through the inner side of the stabilizing disk (310), the driving groove (49) being in communication with the auxiliary groove (48), a first plug-in rod (410) being slidably connected inside the driving groove (49), the first plug-in rod (410) being arranged just inside the rotating roller (311), a second plug-in rod (411) being elastically slidably plugged at both ends of the first plug-in rod (410), the second plug-in rod (411) and the first plug-in rod (410) being combined into a circular ring shape, and a locking rod (412) being fixedly connected to the surface of the first plug-in rod (410) on a side close to the rotating roller (311).

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