CN220943921U - Welding device for steel components - Google Patents

Abstract

The application relates to the field of welding of steel components, in particular to welding equipment for the steel components, which comprises a workbench and a welding device, wherein the welding device comprises a mounting seat and a welding head, and a pair of fixing devices are oppositely arranged on the workbench relative to the welding head; the fixing device comprises a clamping mechanism and a rotating mechanism, wherein the rotating mechanism comprises a toothed ring, a gear and a unidirectional self-locking assembly for limiting unidirectional rotation of the gear, a connecting shaft is fixedly connected to the workbench, the gear is coaxially and rotatably connected with the connecting shaft, and the toothed ring is meshed and matched with the gear; the toothed ring is arranged around the clamping mechanism and fixedly connected with the clamping mechanism. The clamping mechanism and the rotating mechanism are matched, so that the welding head can be used for welding around the joint part of the steel member while the steel member is stably fixed, the production efficiency is improved, and time and labor are saved.

Description

Welding device for steel components

Technical Field

The application relates to the field of welding of steel components, in particular to welding equipment for steel components.

Background

The steel member is a combined member which is formed by connecting steel plates, angle steel, channel steel, I-steel and the like and can bear or transfer load, and is widely applied to the fields of building construction, bridge construction and the like; after the steel member is produced, the steel member is required to be welded, cut, spliced and the like according to specific use environments. In the traditional technology, a manual handheld welding gun is used for welding steel members, and the welding efficiency and the welding precision are low; the existing welding operation is generally completed by welding equipment.

The Chinese patent with the publication number of CN217493136U discloses a steel member welding device, which clamps a steel member through a fixing assembly and then performs welding operation on the steel member; meanwhile, the device gathers the piece clearance that produces when welding through electric putter, clean push pedal and piece guide way cooperation, compares in the prior art, has both increased welding efficiency, has increased the cleanliness factor when welding again.

In view of the above-mentioned related art, the inventor believes that when the requirement for the supporting strength of the steel member is high, it is often necessary to perform welding operation around the joint portion of the two steel members, and after the welding operation of one surface is completed by fixing the steel member by the fixing assembly, if welding is performed on the other surface, it is necessary to manually unscrew the fixing assembly and turn over the steel member so that the welded portion is opposite to the welding head, and then the fixing of the steel member by the fixing assembly is completed, which is time-consuming and labor-consuming, and inconvenient for continuous welding operation.

Disclosure of utility model

In order to optimize the problem that the welding operation of the welding equipment in the related art is complicated when surrounding the welding part of the steel member, the application provides the welding equipment for the steel member.

The application provides a steel member welding device which adopts the following technical scheme:

The welding equipment for the steel components comprises a workbench and a welding device, wherein the welding device comprises a mounting seat and a welding head, and a pair of fixing devices are oppositely arranged on the workbench relative to the welding head; the fixing device comprises a clamping mechanism and a rotating mechanism, wherein the rotating mechanism comprises a toothed ring, a gear and a unidirectional self-locking assembly for limiting unidirectional rotation of the gear, a connecting shaft is fixedly connected to the workbench, the gear is coaxially and rotatably connected with the connecting shaft, and the toothed ring is meshed and matched with the gear; the toothed ring is arranged around the clamping mechanism and fixedly connected with the clamping mechanism.

By adopting the technical scheme, when welding, a constructor firstly places two steel components which are required to be welded into a whole into two clamping mechanisms respectively, and completes fixation; welding and forming the two steel members by utilizing a welding head; if the two steel members are required to have larger supporting strength after being welded, the gear is rotated, the gear drives the toothed ring to rotate, the clamping mechanism and the steel members synchronously rotate along with the toothed ring, and in the rotating process, the welding head surrounds the joint part of the steel members to finish welding operation; the unidirectional self-locking assembly avoids reverse rotation of the gear by constructors, thereby reducing the possibility that the welded part is welded again; the clamping mechanism and the rotating mechanism are matched, so that the welding head can be used for welding around the joint part of the steel member while the steel member is stably fixed, the production efficiency is improved, and time and labor are saved.

In a specific implementation, the unidirectional self-locking assembly comprises a rotary disc, a pawl and an elastic reset piece, wherein the rotary disc is coaxially and rotatably connected with a connecting shaft; one surface of the rotary table is fixedly connected with the gear, a plurality of ratchets are arranged on one surface of the rotary table, which is opposite to the gear, around the connecting shaft, and the ratchets are connected end to end; one end of the pawl is in butt fit with the ratchet, and the other end of the pawl is connected to the connecting shaft through an elastic reset piece.

Through adopting above-mentioned technical scheme, pawl, ratchet and elasticity return piece cooperation for the operator can only rotate carousel and gear along a direction, thereby makes the steel member can not gyration when encircling the joint portion welding, has reduced the inhomogeneous probability of welding.

In a specific embodiment, the unidirectional self-locking assembly further comprises a mounting ring, and one end of the pawl away from the ratchet is fixedly connected with the peripheral wall of the mounting ring; the elastic resetting piece comprises a plurality of elastic pieces, and the elastic pieces are distributed on the inner wall of the mounting ring in an annular array; one end of the elastic sheet is fixedly connected with the inner wall of the mounting ring, and the other end of the elastic sheet is fixedly connected with the connecting shaft.

By adopting the technical scheme, when the turntable rotates, the pawl is abutted by the ratchet and slides along the inclined plane of the ratchet, and at the moment, the elastic reset piece contracts; when the pawl slides out of the inclined plane of the ratchet teeth, the pawl is abutted against the joint of the two adjacent ratchet teeth under the reset action of the elastic reset piece, and at the moment, if the pawl reversely rotates, the pawl is abutted against the straight wall of the ratchet teeth, so that the reverse rotation is prevented.

In a specific embodiment, a gripping rod is eccentrically arranged on the side of the gear facing away from the turntable, and the gripping rod is vertically and rotatably connected with the gear.

By adopting the technical scheme, an operator can conveniently rotate the rotary table by means of the gripping rod, so that the gear is driven to rotate.

In a specific embodiment, the clamping mechanism comprises a fixed plate, a clamping plate and a tightening assembly, wherein the clamping plate is arranged opposite to the fixed plate and is in clamping fit with the fixed plate through the tightening assembly; the side wall of the fixed plate far away from the clamping plate is fixedly connected with a connecting rod, and one end of the connecting rod far away from the fixed plate is fixedly connected with the inner wall of the toothed ring.

Through adopting above-mentioned technical scheme, fixed plate, splint and tightening assembly cooperation can firmly the centre gripping fixed with the steel member, the welding operation of being convenient for.

In a specific embodiment, the tightening assembly comprises a "匚" type mounting frame and tightening bolts, wherein the opposite side walls of the "匚" type mounting frame are fixedly connected with the fixing plate, and the clamping plate is slidingly connected between the opposite side walls of the "匚" type mounting frame; the tightening bolt penetrates through the 匚 type mounting frame and is in threaded connection with the 匚 type mounting frame; the end part of the tightening bolt is rotationally connected to one surface of the clamping plate, which is far away from the fixing plate.

Through adopting above-mentioned technical scheme, constructor only need twist and tighten up the bolt and can make splint and fixed plate be close to each other to finally press from both sides tight steel member, convenient and fast.

In a specific implementation, the connecting rod comprises a telescopic rod and a telescopic cylinder, one end of the telescopic rod is fixed on the fixed plate, and the other end of the telescopic rod is connected in the telescopic cylinder in a sliding manner; one end of the telescopic cylinder, which is far away from the telescopic rod, is fixedly connected to the inner wall of the toothed ring; the telescopic cylinder is provided with a tight supporting bolt and a first threaded hole, and the tight supporting bolt is in threaded connection with the first threaded hole and is in tight fit with the telescopic rod.

Through adopting above-mentioned technical scheme, through supporting tight bolt, telescopic cylinder and telescopic link cooperation, constructor can adjust the distance of fixed plate to the ring gear to make the axis of steel member and the axis coincidence of ring gear, the steel member rotates along self axis when rotating along with the ring gear this moment, makes welding operation more convenient.

In summary, the present application includes at least one of the following beneficial technical effects:

the clamping mechanism and the rotating mechanism are matched, so that the welding head can be used for welding around the joint part of the steel member while the steel member is stably fixed, the production efficiency is improved, and time and labor are saved;

The pawl, the ratchet and the elastic reset piece are matched, so that an operator can only rotate the rotary table and the gear in one direction, the steel member cannot rotate when being welded around the joint part, and the probability of uneven welding is reduced;

The clamping plate, the fixing plate and the tightening assembly are matched, so that the steel member can be firmly clamped and fixed;

According to the '匚' type mounting frame and the tightening bolt, the constructor can enable the clamping plate and the fixing plate to be close to each other only by screwing the tightening bolt, and finally the steel member is clamped, so that the steel member is convenient and quick;

the connecting rod adopts the telescopic structure of the telescopic rod and the telescopic cylinder, so that the distance between the fixing plate and the inner wall of the toothed ring is adjustable, the axial direction of the steel member is overlapped with the axial line of the toothed ring as much as possible, and the welding operation is convenient.

Drawings

FIG. 1 is a schematic view showing the overall structure of a welding apparatus for steel members according to an embodiment of the present application;

FIG. 2 is an exploded view showing the relationship of the gear meshing with the ring gear and the relationship of the ring gear coupling with the mounting bracket;

FIG. 3 is a schematic view of a partial structure for embodying the connection relationship between gears, connecting shafts and single-wire self-locking assemblies;

FIG. 4 is a schematic diagram of a structure for embodying the connection of the clamping mechanism and the toothed ring;

FIG. 5 is an exploded view of a connecting rod used to embody the connection between the connecting rod and the fixed plate, tightening assembly and clamping plate;

fig. 6 is an enlarged schematic view of the portion a in fig. 5.

Reference numerals illustrate: 1. a work table; 11. a mounting frame; 111. rotating ball; 2. a welding device; 21. a mounting base; 22. a welding head; 3. a fixing device; 4. a clamping mechanism; 41. a fixing plate; 42. a clamping plate; 421. a rotary groove; 422. a turning hole; 43. a tightening assembly; 431. a '匚' type mounting frame; 432. tightening the bolts; 433. a second threaded hole; 434. a rotating piece; 44. a connecting rod; 441. a telescopic rod; 442. a telescopic cylinder; 443. abutting the bolt; 444. a first threaded hole; 5. a rotating mechanism; 51. a gear; 52. a toothed ring; 521. a ring groove; 53. a connecting shaft; 54. a unidirectional self-locking assembly; 541. a turntable; 542. a pawl; 543. a spring plate; 544. a ratchet; 545. a mounting ring; 546. a round groove is arranged; 547. gripping the rod.

Detailed Description

The application is described in further detail below with reference to fig. 1-6.

In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present application and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present application.

The embodiment of the application discloses welding equipment for steel components. Referring to fig. 1, a welding apparatus for steel members includes a table 1, on which a welding device 2 and a pair of fixing devices 3 are provided on the table 1; the welding device 2 comprises a mounting seat 21 and a welding head 22, wherein the mounting seat 21 is arranged on the workbench 1, and the welding head 22 is arranged at the bottom of the mounting seat 21; a pair of fixing devices 3 are respectively and oppositely arranged at two sides of the welding head 22 and are used for clamping and fixing two steel components to be welded and formed and assisting the welding of the steel components tightly.

Referring to fig. 1, the fixing device 3 includes a clamping mechanism 4 and a rotating mechanism 5, wherein the clamping mechanism 4 is used for clamping and fixing the steel member, and the rotating mechanism 5 is used for driving the clamping mechanism 4 and the steel member to synchronously rotate, so that the steel member can be uniformly welded under the condition that the welding head 22 is not moved.

Referring to fig. 1 and 2, in order to facilitate the installation of the components of the rotating mechanism 5, a pair of shaft seats 12 are provided on the workbench 1 opposite to the installation seat 21, a connecting shaft 53 is fixedly connected between the two shaft seats 12, and the length direction of the connecting shaft 53 is the same as the length direction of the steel member during welding; the rotating mechanism 5 comprises a toothed ring 52 and a gear 51, wherein the gear 51 is coaxially and rotatably connected to a connecting shaft 53 and is meshed and matched with the outer wall of the toothed ring 52; the straight side wall of the toothed ring 52 is provided with a rotary groove 421 in a surrounding mode, five pairs of rotary balls 111 are uniformly connected to the mounting frame 11 in a rotary mode, and each pair of rotary balls 111 clamps the toothed ring 52 and is in rolling fit with the rotary groove 421; the clamping mechanism 4 is built in the toothed ring 52 and fixedly connected with the inner wall of the toothed ring 52 so as to ensure that the steel member can rotate synchronously with the toothed ring 52.

It should be noted that, the present application drives the clamping mechanism 4 and the steel member to rotate by means of the cooperation rotation of the gear 51 and the toothed ring 52, so that the welding head 22 welds the steel member uniformly, thus being suitable for long strip-shaped, axial and relatively regular steel members, such as steel pipes, channel steels, I-steel, angle steels, etc.; if the welding operation of steel plates, irregular non-axial deformed steel and other steel components is to be completed, the welding mode in the traditional technology can be selected for welding.

Referring to fig. 2 and 3, in order to avoid the phenomenon that the constructor reversely rotates the gear 51 to cause uneven welding of the welding part of the steel member, the rotating mechanism 5 in the embodiment further comprises a unidirectional self-locking assembly 54 to ensure that the gear 51 and the toothed ring 52 can rotate in one direction; the unidirectional self-locking assembly 54 comprises a turntable 541, a pawl 542 and an elastic reset piece, the turntable 541 is rotatably connected to the connecting shaft 53, and the axis of the turntable 541 is coincident with the axis of the connecting shaft 53; one side of the turntable 541 is fixedly connected with the straight wall of the gear 51, the other side of the turntable 541 is provided with a yielding circular groove 546, a plurality of ratchets 544 are annularly arranged on the circular groove wall of the yielding circular groove 546 in an array, the ratchets 544 are connected end to end, one end of each pawl 542 is fixedly connected to the connecting shaft 53 through an elastic reset piece, and the other end of each pawl 542 points to the ratchets 544 and is in abutting fit with the ratchets 544; in order to facilitate the operator to rotate the turntable 541 and the gear 51, a grip lever 547 is rotatably connected to a straight wall of the turntable 541 away from the gear 51, and the grip lever 547 is eccentrically disposed.

The elastic reset piece of the application can be a torsion spring, and the connection relation is as follows: the torsion spring is arranged on the connecting shaft 53 in a penetrating way, one end of the torsion spring is fixedly connected with the connecting shaft 53, and the other end of the torsion spring is fixedly connected to the pawl 542; considering the requirements of actual construction on elastic deformation and compression reset time, the elastic reset piece of the application adopts a plurality of elastic sheets 543; the bottom of pawl 542 is equipped with collar 545, and collar 545 overlaps and establishes on connecting axle 53, and the inner wall of collar 545 leaves the space with connecting axle 53, and shell fragment 543 one end fixed connection is on the inner wall of collar 545, and the other end and connecting axle 53 fixed connection, a plurality of shell fragments 543 annular array distribute in the space that collar 545 and connecting axle 53 set up the formation.

Referring to fig. 3, before the turntable 541 rotates, the ends of the pawls 542 abut at the end-to-end connection of two adjacent ratchet teeth 544; during the process that the operator rotates the rotary table 541, the ratchet 544 rotates synchronously with the rotary table 541, and the pawl 542 is relatively fixed on the connecting shaft 53, so that the end of the pawl 542 slides along the inclined wall of the ratchet 544 and gradually compresses the elastic sheet 543; when the end of the pawl 542 slides away from the inclined wall of the ratchet 544, the pawl 542 is abutted against the joint of the ratchet 544 at the next position under the reset action of the elastic piece 543, and when the rotary plate 541 is reversed, the pawl 542 is abutted against the straight wall of the ratchet 544 to play a limiting role and prevent the reverse rotation, so that the rotary plate 541 and the gear 51 can be rotated only in a single direction by an operator, the problem of uneven welding or uneven welding parts caused by the fact that the welded parts are welded again is avoided, and the subsequent operations of polishing and polishing the welded parts are simplified.

Referring to fig. 4 and 5, the clamping mechanism 4 includes a fixing plate 41, a clamping plate 42, and a tightening assembly 43, the tightening assembly 43 being used to push the clamping plate 42 close to the fixing plate 41, so as to clamp and fix the steel member between the clamping plate 42 and the fixing plate 41; three connecting rods 44 are vertically and fixedly connected to the inner wall of the toothed ring 52, and the length directions of the three connecting rods 44 are all the radial directions of the toothed ring 52; one end of the connecting rod 44 far away from the toothed ring 52 extends to the axle center of the toothed ring 52 and is fixedly connected with the fixed plate 41; the three connecting rods 44 are uniformly connected to the fixed plate 41; the side of the fixed plate 41 facing away from the link 44 faces the clamping plate 42, and the clamping plate 42 is connected to the fixed plate 41 by a tightening assembly 43.

Referring to fig. 4 and 5, the tightening assembly 43 includes a "匚" type mounting frame 431 and a tightening bolt 432, two mutually parallel straight walls of the "匚" type mounting frame 431 are fixedly mounted on the fixing plate 41, and the clamping plate 42 is located between the two straight walls of the "匚" type mounting frame 431; the side wall of the 匚' type mounting frame 431 parallel to the clamping plate 42 is provided with a second threaded hole 433, the tightening bolt 432 is in threaded fit with the second threaded hole 433, and the end part of the tightening bolt 432 extends to the clamping plate 42; the side wall of the clamping plate 42, which is close to the tightening bolt 432, is provided with a rotary hole 422 and a rotary groove 421, the rotary hole 422 is communicated with the rotary groove 421, and the rotary groove 421 is positioned at one side of the rotary hole 422, which is far away from the tightening bolt 432; the rotary slot 421 is rotatably connected with a rotary piece 434, and the end of the tightening bolt 432 is arranged in the rotary hole 422 in a penetrating manner and fixedly connected with the rotary piece 434.

By tightening the screw-fit of the bolt 432 and the second screw hole 433, the constructor can clamp and fix the steel member by the clamping plate 42 and the fixing plate 41 conveniently; after the welding operation is finished, the constructor unscrews the tightening bolt 432, and at this time, under the cooperation of the rotary piece 434 and the rotary groove 421, the constructor does not need to manually stir, and the clamping plate 42 can automatically slide in a direction away from the fixed plate 41, so that the welding operation is more convenient.

Referring to fig. 5 and 6, the link 44 includes a telescopic rod 441 and a telescopic cylinder 442, one end of the telescopic rod 441 is fixedly connected to the fixed plate 41, the other end of the telescopic rod 441 extends into the telescopic cylinder 442 and is slidably matched with the telescopic cylinder 442, and the telescopic cylinder 442 is fixedly connected to the inner wall of the toothed ring 52; the circumferential wall of the telescopic cylinder 442 is provided with a first threaded hole 444 in a penetrating manner, a tightening bolt 443 is connected in the first threaded hole 444 in a threaded manner, and the end wall of the tightening bolt 443 is in tight fit with the side wall of the telescopic rod 441.

The implementation principle of the welding equipment for the steel member provided by the embodiment of the application is as follows: during welding, a constructor firstly correspondingly places two steel members to be welded into a whole between the two clamping mechanisms 4, and the steel members are positioned between the clamping plates 42 and the fixing plates 41; when the joint of the two steel members is located right below the welding head 22, the tightening bolt 432 is screwed, and the rotary piece 434 on the tightening bolt 432 and the rotary groove 421 are in running fit, so that the clamping plate 42 gradually approaches the fixed plate 41 and abuts against the steel members; after the clamping of the steel member is completed, an operator adjusts the sliding distance of the telescopic rod 441 into the telescopic cylinder 442 through the abutting bolt 443 so that the axis of the steel member coincides with the axis of the toothed ring 52 as much as possible, and then the abutting bolt 443 is screwed down; at this time, all the clamping and fixing processes of the steel member are completed; starting the welding head 22, and welding the joint part of the two steel members by the welding head 22, wherein at the moment, a constructor rotates the rotary table 541 through the grip rod 547, the rotary table 541 drives the gear 51 to rotate, the toothed ring 52 rotates under the meshing action of the gear 51, and the steel members and the clamping mechanism 4 synchronously rotate along with the toothed ring 52, so that the welding head 22 surrounds the joint part of the two steel members to weld, and the welded steel members have larger supporting strength; in the process of rotating the turntable 541 by a constructor, the pawl 542 and the ratchet 544 are matched, so that the constructor cannot reversely rotate the turntable 541, the welded part is ensured not to be welded again in the rotating process, the uniformity of welding is improved, and the support strength of the two welded steel members is further improved.

The above embodiments are not intended to limit the scope of the present application, so: all equivalent changes in structure, shape and principle of the application should be covered in the scope of protection of the application.

Claims (7)

1. Welding equipment for steel components, comprising a workbench (1) and a welding device (2), wherein the welding device (2) comprises a mounting seat (21) and a welding head (22), and is characterized in that: a pair of fixing devices (3) are oppositely arranged on the workbench (1) relative to the welding head (22); the fixing device (3) comprises a clamping mechanism (4) and a rotating mechanism (5), the rotating mechanism (5) comprises a toothed ring (52), a gear (51) and a unidirectional self-locking assembly (54) for limiting unidirectional rotation of the gear (51), a connecting shaft (53) is fixedly connected to the workbench (1), the gear (51) is coaxially and rotatably connected with the connecting shaft (53), and the toothed ring (52) is meshed and matched with the gear (51); the toothed ring (52) is arranged around the clamping mechanism (4) and is fixedly connected with the clamping mechanism (4).

2. The welding apparatus for steel members according to claim 1, wherein: the unidirectional self-locking assembly (54) comprises a rotary disc (541), a pawl (542) and an elastic reset piece, and the rotary disc (541) is coaxially and rotatably connected with the connecting shaft (53); one surface of the rotary table (541) is fixedly connected with the gear (51), a plurality of ratchets (544) are arranged on one surface of the rotary table (541) facing away from the gear (51) around the connecting shaft (53), and the ratchets (544) are connected end to end; one end of the pawl (542) is in abutting fit with the ratchet (544), and the other end of the pawl is connected to the connecting shaft (53) through an elastic reset piece.

3. The welding apparatus for steel members according to claim 2, wherein: the unidirectional self-locking assembly (54) further comprises a mounting ring (545), and one end of the pawl (542) far away from the ratchet (544) is fixedly connected with the peripheral wall of the mounting ring (545); the elastic reset piece comprises a plurality of elastic pieces (543), and the elastic pieces (543) are distributed on the inner wall of the mounting ring (545) in a ring-shaped array; one end of the elastic sheet (543) is fixedly connected with the inner wall of the mounting ring (545), and the other end of the elastic sheet is fixedly connected with the connecting shaft (53).

4. The welding apparatus for steel members according to claim 2, wherein: one surface of the gear (51) facing away from the turntable (541) is eccentrically provided with a gripping rod (547), and the gripping rod (547) is vertically and rotatably connected with the gear (51).

5. The welding apparatus for steel members according to claim 1, wherein: the clamping mechanism (4) comprises a fixed plate (41), a clamping plate (42) and a tightening assembly (43), wherein the clamping plate (42) is arranged opposite to the fixed plate (41) and is in clamping fit with the fixed plate (41) through the tightening assembly (43); the side wall of the fixed plate (41) far away from the clamping plate (42) is fixedly connected with a connecting rod (44), and one end of the connecting rod (44) far away from the fixed plate (41) is fixedly connected with the inner wall of the toothed ring (52).

6. The welding apparatus for steel members according to claim 5, wherein: the tightening assembly (43) comprises a '匚' type mounting frame (431) and tightening bolts (432), opposite side walls of the '匚' type mounting frame (431) are fixedly connected with the fixing plate (41), and the clamping plate (42) is slidingly connected between opposite side walls of the '匚' type mounting frame (431); the tightening bolt (432) is arranged on the 匚 mounting frame (431) in a penetrating mode and is in threaded connection with the 匚 mounting frame (431); the end of the tightening bolt (432) is rotatably connected to the side of the clamping plate (42) away from the fixed plate (41).

7. The welding apparatus for steel members according to claim 5, wherein: the connecting rod (44) comprises a telescopic rod (441) and a telescopic cylinder (442), one end of the telescopic rod (441) is fixed on the fixed plate (41), and the other end of the telescopic rod is connected in the telescopic cylinder (442) in a sliding manner; one end of the telescopic cylinder (442) far away from the telescopic rod (441) is fixedly connected to the inner wall of the toothed ring (52); the telescopic cylinder (442) is provided with a tightening bolt (443) and a first threaded hole (444), and the tightening bolt (443) is in threaded connection with the first threaded hole (444) and is in tight fit with the telescopic rod (441).