Fixing tool
By designing adjustable pressure plates and fixed arm assemblies, the problem of low compatibility of existing fixed tooling with aerospace parts has been solved, enabling stable fixation and efficient welding of complex workpieces.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-24
- Publication Date
- 2026-03-31
AI Technical Summary
Existing fixed tooling has low adaptability to pre-welding assembly and positioning of complex structural parts such as thin-walled and skin-covered stringers in aerospace components, and is difficult to meet the needs of various welding processes.
A fixed fixture was designed, including a vertically movable pressure plate and multiple fixed arm assemblies. By sliding and adjusting the position and height of the pressure component, it can adapt to complex workpieces with different fixing points and enhance the adaptability to the workpieces to be welded.
It improves the adaptability of fixed fixtures to workpieces with complex structures, ensures welding accuracy and reliability, reduces the need for fixed fixtures for different workpiece types, and improves reliability and efficiency.
Smart Images
Figure CN224058910U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to welding technical field especially relates to a fixed frock. BACKGROUND
[0002] Friction stir welding mainly generates a large amount of friction heat through the high-speed rotation of the stir head and the constant friction of the base material, so that the material around the weld is softened, the stir head is further extruded and rotated to promote the flow of plastic metal, so that the solid-phase connection of the material is realized. In the manufacturing process of aerospace parts, a fixed frock is often used to fix the workpiece to be welded, and then the friction stir welding is carried out.
[0003] However, there are a large number of thin-walled, skin stringer and other complex structure parts in aerospace parts, and these complex structure parts generally include two or more than two welding processes, which puts higher demands on the pre-weld assembly and positioning of the friction stir welding technology. The fixed frock in the prior art is often only suitable for the lap joint and butt joint between thin plates, and cannot meet the lap joint and butt joint of thin plates and long stringers and other complex components. Therefore, it is urgent to provide a fixed frock to solve the above problems. SUMMARY
[0004] The first purpose of the utility model is to provide a fixed frock to solve the technical problem of low adaptability of the fixed frock in the prior art to the workpiece to be welded.
[0005] As conceived above, the technical scheme adopted by the utility model is:
[0006] A fixed frock, comprising a fixed seat, the fixed frock comprising a pressing plate and a fixed arm assembly, the pressing plate being movably mounted on the upper end face of the fixed seat to press the workpiece to be welded, the fixed arm assembly being provided with a plurality of fixed arm assemblies and being respectively mounted on the fixed seat;
[0007] The fixed arm assembly comprises a supporting arm and a pressing piece, the first end of the supporting arm is mounted on the fixed seat, the second end of the supporting arm extends in the horizontal direction, the pressing piece is slidably mounted on the supporting arm along the length direction of the supporting arm, and the pressing piece can move up and down to press the workpiece to be welded.
[0008] Optionally, the pressing piece comprises a horizontal adjusting part and a pressing part movably connected, the supporting arm is provided with a sliding groove along its extending direction, and the horizontal adjusting part is slidably mounted in the sliding groove.
[0009] Optionally, the pressing part is located below the horizontal adjusting part, one of the horizontal adjusting part and the pressing part is provided with a threaded rod, and the other is provided with a threaded hole, the threaded rod extends vertically and cooperates with the threaded hole.
[0010] Optionally, the pressing part has a conical structure, and the small end of the pressing part faces downward.
[0011] Optionally, a set of fixing arm assemblies is provided on opposite sides of the fixing base along the first direction, and each set of fixing arm assemblies includes multiple fixing arm assemblies spaced apart along the second direction, with the fixing arm assemblies on both sides of the fixing base extending toward each other.
[0012] Optionally, the fixed base has raised steps protruding upwards on both sides, and the first end of the support arm is installed on the upper side of the raised steps.
[0013] Optionally, the fixed arm assembly further includes a mounting member, which is mounted on the fixed base, and the first end of the support arm is connected to the mounting member. The mounting member is rotatably mounted on the fixed base with its rotation axis vertically arranged.
[0014] Alternatively, the support arm extends along the first direction.
[0015] Optionally, the pressure plate is characterized by having two plates arranged horizontally at intervals.
[0016] Optionally, the fixing fixture further includes a support block, which is used to cooperate with the pressing member to clamp the workpiece to be welded;
[0017] And / or, the fixing fixture includes a plurality of auxiliary limiting members, one end of which is rotatably mounted on the fixing base, and the other end of which can abut against the upper side of the pressure plate.
[0018] Optionally, the fixing fixture includes multiple limiting sliders, which are slidably mounted on the periphery of the fixing seat to horizontally press against the workpiece to be welded;
[0019] And / or, the fixing fixture further includes a plurality of threaded clamping members, which are threadedly installed on the periphery of the fixing seat and located below the pressure plate to horizontally press against the workpiece to be welded.
[0020] The beneficial effect of the fixing fixture proposed in this utility model is that by setting a pressure plate to press against the plate-shaped part of the workpiece to be welded, and by setting a fixing arm assembly, the mounting part of the fixing arm assembly is installed on the fixing base, the support arm is connected to the mounting part, and the pressing part is slidably installed on the support arm along the length direction of the support arm. The pressing part can move up and down to press against the workpiece to be welded, so that the pressing part slides along the support arm to reach different fixing positions. The up and down movement of the pressing part can also adapt to the height of different fixing points. Finally, when facing a workpiece with a complex structure to be welded, multiple fixing arm assemblies can reach fixing points at different positions and heights for reliable fixing, thereby improving the adaptability of the fixing fixture to the workpiece to be welded. Attached Figure Description
[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of this utility model and these drawings without creative effort.
[0022] Fig. 1 This is a schematic diagram of the structure of a fixing fixture provided in an embodiment of this utility model;
[0023] Fig. 2 This is another structural schematic diagram of a fixing fixture provided in an embodiment of this utility model.
[0024] In the picture:
[0025] 1. Fixed base; 11. Heightening step; 2. Pressure plate; 3. Fixed arm assembly; 31. Mounting component; 32. Support arm; 33. Pressing component; 331. Horizontal adjustment part; 332. Pressing part; 4. Auxiliary limiting component; 5. Limiting slider; 6. Threaded tightening component; 7. Support block. Detailed Implementation
[0026] To make the technical problem solved by this utility model, the technical solution adopted, and the technical effect achieved clearer, the technical solution of this utility model will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely for explaining this utility model and not for limiting it. Furthermore, it should be noted that, for ease of description, only the parts related to this utility model are shown in the accompanying drawings, not all of them.
[0027] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0028] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0029] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature. In the description of this embodiment, unless otherwise specified, "multiple" specifically refers to two or more.
[0030] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.
[0031] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on the other component or it can be located in between the component.
[0032] The technical solution of this utility model will be further described below with reference to the accompanying drawings and specific embodiments.
[0033] This embodiment provides a fixed fixture to solve the technical problem of low adaptability of existing fixed fixtures to the workpiece to be welded.
[0034] like Figs. 1-2 As shown in the figure, this embodiment proposes a fixing fixture for fixing parts to be welded, wherein the parts to be welded include a first part to be welded and a second part to be welded. The fixing fixture includes a fixing base 1, a pressure plate 2, and a fixing arm assembly 3. The pressure plate 2 is movably mounted on the upper end face of the fixing base 1 to press against the workpiece to be welded. Multiple fixing arm assemblies 3 are provided and respectively mounted on the fixing base 1. The fixing arm assembly 3 includes a support arm 32 and a pressing member 33. The first end of the support arm 32 is mounted on the fixing base 1, and the second end of the support arm 32 extends in the horizontal direction. The pressing member 33 is slidably mounted on the support arm 32 along the length direction of the support arm 32 and can move up and down to press against the workpiece to be welded.
[0035] Specifically, the workpiece to be welded pressed by the pressure plate 2 is the first workpiece to be welded, which is generally a plate-shaped workpiece and serves as the base for overlapping the second workpiece to be welded; the workpiece to be welded pressed by the pressure member 33 is the second workpiece to be welded, which is generally a long stringer with a more complex structure.
[0036] Understandably, the structures and types of workpieces to be welded are diverse, and existing fixing methods are relatively simple. When faced with workpieces with complex structures, they are often difficult to fix effectively, or when there are various types of workpieces to be welded, different fixing tools need to be produced, which is very time-consuming and labor-intensive. In this embodiment, in order to improve the adaptability of the fixing tool to the workpieces to be welded, a vertically movable pressure plate 2 is set to initially fix the workpieces to be welded. Multiple fixing arm assemblies 3 are set, and their pressing members 33 can slide along the length of the support arm 32 to reach different positions. The pressing members 33 themselves can also move up and down to adapt to different heights of the fixing position. Therefore, when facing workpieces with complex structures, multiple pressing members 33 can be slid to selectively fix any position and any height. In addition, when facing different types of workpieces to be welded, since the position and height of the pressing members 33 are adjustable, there is no need to design additional fixing tools, thereby improving the adaptability to fixing different types of workpieces to be welded.
[0037] Taking the overlapping of two workpieces to be welded, a thin plate and a Z-shaped stringer, as an example, the first workpiece to be welded is the thin plate, and the second workpiece to be welded is the Z-shaped stringer. The pressure plate 2 moves up and down to press the thin plate and the bottom plate of the Z-shaped stringer together. Then, the pressing member 33 moves downwards to press against the pressure plate 2, further fixing the thin plate and the bottom plate of the Z-shaped stringer. At this time, the top plate of the Z-shaped stringer is not fixed. The top plate of the Z-shaped stringer is located on the other side of its bottom plate in the horizontal direction. If it is not effectively fixed, displacement is very likely to occur during welding, thus affecting the welding accuracy. Part of the fixing arm assembly 3 can extend to the top plate of the Z-shaped stringer. Through the pressing member 33, different positions of the top plate of the Z-shaped stringer are pressed and fixed, ultimately firmly fixing the Z-shaped stringer above the thin plate, completing the positioning.
[0038] In this embodiment, the length direction of the second component to be welded is the second direction, and the first direction is horizontal and perpendicular to the second direction.
[0039] Optionally, a set of fixing arm assemblies 3 are respectively provided on opposite sides of the fixing base 1 along the first direction. Each set of fixing arm assemblies 3 includes multiple fixing arm assemblies 3 spaced apart along the second direction, with the fixing arm assemblies 3 on both sides of the fixing base 1 extending towards each other. This arrangement allows multiple fixing arm assemblies 3 to be arranged on both sides of the workpiece to be welded, which not only facilitates multi-point comprehensive fixing of the workpiece to be welded, but also helps to maintain the balance on both sides of the workpiece to be welded, making it less prone to tipping over, thereby improving the reliability of the fixing fixture.
[0040] Optionally, the fixed arm assembly 3 also includes a mounting member 31, which is mounted on the fixed base 1, and the first end of the support arm 32 is connected to the mounting member 31. The mounting member 31 provides an installation position for the support arm 32, improving the overall structural rationality.
[0041] Furthermore, in this embodiment, the mounting component 31 is fixedly disposed on the fixing base 1, and the support arm 32 extends along the first direction. This arrangement improves the structural strength of the fixing arm assembly 3, thereby enhancing the reliability of the fixing fixture.
[0042] In other embodiments, the mounting component 31 can also be rotatably mounted on the fixed base 1, with the axis of rotation vertically arranged. This arrangement enables the fixed arm assembly 3 to have a rotation function, allowing the support arm 32 to reach different directions of the workpiece to be welded, thereby selecting more fixed positions and adapting to more types of workpieces to be welded, thus expanding the application scenarios of the fixed fixture.
[0043] Optionally, the pressing member 33 includes a horizontal adjustment part 331 and a pressing part 332 that are movably connected to each other. The support arm 32 has a groove along its extension direction, and the horizontal adjustment part 331 is slidably installed in the groove. This arrangement provides installation space for the horizontal adjustment part 331 in the support arm 32, improves the smoothness of sliding of the pressing member 33, and enhances the structural rationality of the fixing fixture.
[0044] Optionally, the pressing part 332 is located below the horizontal adjustment part 331. One of the horizontal adjustment part 331 and the pressing part 332 is provided with a threaded rod, and the other is provided with a threaded hole. The threaded rod extends vertically and mates with the threaded hole. This arrangement allows the pressing part 332 to move closer to or further away from the horizontal adjustment part 331 in the vertical direction by screwing the threaded rod in the threaded hole, thereby enabling the pressing part 332 to abut against the workpiece to be welded. The structure is simple and the operation is reliable.
[0045] To prevent the threaded rod from dislodging downwards from the groove, the upper end of the threaded rod has a head, the lower end of which abuts against the support arm 32. This design prevents the pressing member 33 from moving downwards and dislodging from the support arm 32, thus improving the reliability of the fixture.
[0046] Furthermore, the fixed arm assembly 3 also includes a locking ring. The locking ring has a threaded hole and is threaded onto the outer periphery of the threaded rod, and the locking ring is located between the horizontal adjustment part 331 and the pressing part 332. Understandably, when the pressing part 33 slides to the required pressing position, in order to prevent the pressing part 33 from sliding during the welding process and thus deviating from the pressing position, the locking ring can be rotated to move closer to the horizontal adjustment part 331 until the locking ring presses against the support arm 32, that is, the locking ring and the end of the threaded rod together clamp the support arm 32, and the horizontal adjustment part 331 cannot move, thus entering a locked state.
[0047] Optionally, the support arm 32 can be movably connected to the mounting member 31. This arrangement can further increase the range of vertical movement of the movable member, thereby increasing the adaptability of the fixed arm assembly 3 to different workpiece heights to be welded.
[0048] For example, a multi-stage telescopic sleeve is provided between the mounting component 31 and the first end of the support arm 32. When the range of vertical movement of the pressing component 33 still does not meet the height range of the workpiece to be welded, it is necessary to adjust the height of the support arm 32. At this time, controlling the extension and retraction of the multi-stage telescopic sleeve can realize the lifting and lowering of the support arm, thereby improving the adaptability of the fixed fixture to different workpieces to be welded.
[0049] Furthermore, one of the two adjacent sleeves is equipped with a gear, and the other with a rack, which mesh with each other. The sleeve with the gear is also equipped with a locking pin, which can prevent the gear from rotating. When the support arm 32 reaches the specified height, pressing the locking pin on the sleeve prevents the gear from rotating, and at the same time, the rack cannot move. The multi-stage telescopic sleeve enters a locked state, preventing the height of the support arm 32 from changing.
[0050] It should be noted that the above-described multi-stage telescopic sleeve structure is only an exemplary structure. Existing multi-stage telescopic sleeve structures can be applied to this embodiment, but this embodiment does not limit or elaborate on them.
[0051] To enhance the pressing effect of the pressing member 33 on the workpiece to be welded, the pressing part 332 may optionally have a conical structure, with the smaller end of the pressing part 332 facing downwards. This arrangement can increase the pressure of the pressing member 33 against the workpiece to be welded, thereby making the workpiece to be welded more firmly positioned on the fixing seat 1 and improving the reliability of the fixing fixture.
[0052] To avoid interference between the fixed arm assembly 3 and the workpiece to be welded in the height direction, and to reduce the height adjustment range of the fixed arm assembly 3, optionally, the fixed base 1 is provided with raising steps 11 protruding upwards on opposite sides along the first direction, and the mounting part 31 is installed on the upper side of the raising steps 11. The pressure plate 2 is disposed between the two raising steps 11.
[0053] To further improve the reliability of the fixture, optionally, two pressure plates 2 are horizontally spaced. This arrangement enhances the fixing strength of the workpiece to be welded, thereby increasing the reliability of the fixture.
[0054] To prevent the pressure plate 2 from shifting, the fixing fixture optionally includes multiple auxiliary limiting members 4, one end of which is installed on the fixing base 1, and the other end of which can abut against the upper side of the pressure plate 2. This arrangement can prevent the pressure plate 2 from shifting and affecting the welding accuracy, and improve the fixing effect of the fixing fixture.
[0055] Optionally, multiple auxiliary limiting members 4 are provided and located at the edge of the fixed base 1. This arrangement can prevent the auxiliary limiting members 4 from interfering with other components on the fixed base 1, optimize the space utilization of the fixed base 1, and thus improve the reliability of the fixed tooling.
[0056] Optionally, the fixing fixture includes multiple limiting sliders 5, which are slidably mounted on the periphery of the fixing base 1 to horizontally press against the workpiece to be welded. This arrangement, by using the limiting sliders 5 to abut and fix the workpiece from the circumference, increases the positioning strength of the workpiece to be welded and improves the positioning effect.
[0057] For example, the fixing base 1 is provided with grooves on opposite sides along the second direction, and the limiting slider 5 is slidably disposed on the groove wall. This configuration provides a reasonable installation position for the limiting slider 5 and improves the structural rationality of the fixing fixture.
[0058] Optionally, the fixing fixture also includes multiple threaded clamping elements 6, which are threadedly installed on the periphery of the fixing seat 1 and located below the pressure plate 2 to horizontally press against the workpiece to be welded. This arrangement increases the fixing strength of the workpiece to be welded, and the location of the threaded clamping elements 6 below the pressure plate 2 also avoids interference with the pressure plate 2, improving the structural rationality of the fixing fixture.
[0059] In this embodiment, the limiting slider 5 is slidably installed on both sides of the fixed base 1 along the second direction, and presses and fixes the workpiece to be welded from the second direction. The threaded clamping member 6 is located below the pressure plate 2, and presses and fixes the workpiece to be welded from the first direction. This arrangement effectively fixes both sides of the workpiece to be welded in the first direction and the second direction, thereby improving the positioning reliability of the workpiece to be welded.
[0060] Optionally, the fixing fixture also includes a support block 7, which cooperates with the pressing member 33 to clamp the workpiece to be welded. This arrangement enables the fixing fixture to prevent the workpiece from being bent when facing a workpiece with a complex structure, such as one with a certain gap, thereby protecting the workpiece. Taking a Z-shaped stringer as an example, there is a gap between the top plate and the thin plate of the Z-shaped stringer. Using the support block 7 to support the top plate of the Z-shaped stringer in this gap can prevent the top plate of the Z-shaped stringer from being bent, and at the same time prevent the Z-shaped stringer from tilting due to uneven force on both sides.
[0061] Taking the overlapping of two workpieces to be welded, a thin plate and a Z-shaped stringer, as an example, the working process of the fixing fixture in this embodiment is as follows:
[0062] First, place the thin plate on the upper surface of the fixed base 1, place the Z-shaped stringer on top of the thin plate, and lower the pressure plate 2 to press down the thin plate and the bottom plate of the Z-shaped stringer.
[0063] Place the support block 7 between the top plate of the Z-shaped stringer and the upper surface of the thin plate. Rotate the auxiliary limiting piece 4 to press down the upper end of the pressure plate 2. Then rotate part of the fixed arm assembly 3 so that multiple pressing pieces 33 press against different positions of the pressure plate 2. Rotate another part of the fixed arm assembly 3 so that multiple pressing pieces 33 press against the top plate of the Z-shaped stringer to complete the overlap of the thin plate and the Z-shaped stringer.
[0064] Spot weld the two ends of the Z-shaped stringer for initial fixation;
[0065] Move the pressure plate 2 a preset distance away from the workpiece to be welded, exposing the bottom plate of the Z-shaped stringer, and perform multi-point welding on the bottom plate and thin plate of the Z-shaped stringer.
[0066] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention. The scope of the present invention is determined by the scope of the appended claims.
Claims
1. A fixing tool comprising a fixing seat (1), characterized in that, The fixing tool comprises a pressing plate (2) and a plurality of fixing arm assemblies (3), the pressing plate (2) is movably arranged on the upper end face of the fixing base (1) to press the workpiece to be welded, and the fixing arm assemblies (3) are arranged on the fixing base (1); The fixing arm assembly (3) comprises a supporting arm (32) and a pressing piece (33), the first end of the supporting arm (32) is arranged on the fixing base (1), the second end of the supporting arm (32) extends in the horizontal direction, and the pressing piece (33) is slidably arranged on the supporting arm (32) along the length direction of the supporting arm (32), and the pressing piece (33) is movable to press the workpiece to be welded.
2. The fixture of claim 1, wherein The pressing piece (33) comprises a horizontal adjusting part (331) and a pressing part (332) movably connected, and the supporting arm (32) is provided with a sliding groove along the extending direction of the supporting arm (32), and the horizontal adjusting part (331) is slidably arranged in the sliding groove.
3. The fixture of claim 2, wherein The pressing part (332) is located below the horizontal adjusting part (331), one of the horizontal adjusting part (331) and the pressing part (332) is provided with a threaded rod, and the other is provided with a threaded hole, and the threaded rod extends vertically and cooperates with the threaded hole.
4. The fixture of claim 2, wherein The pressing part (332) is in a tapered structure, and the small end of the pressing part (332) faces downward.
5. The fixture of claim 1, wherein The fixing base (1) is provided with a group of fixing arm assemblies (3) on the opposite sides in the first direction, each group of the fixing arm assemblies (3) comprises a plurality of fixing arm assemblies (3) arranged in the second direction, and the fixing arm assemblies (3) on the opposite sides of the fixing base (1) extend towards each other.
6. The fixture of claim 5, wherein The fixing base (1) is provided with a raised step (11) on the opposite sides upward, and the first end of the supporting arm (32) is arranged on the upper side of the raised step (11).
7. The fixture of claim 5, wherein The fixing arm assembly (3) further comprises a mounting piece (31), the mounting piece (31) is arranged on the fixing base (1), the first end of the supporting arm (32) is connected to the mounting piece (31), and the mounting piece (31) is rotatably arranged on the fixing base (1) and the rotating axis is vertically arranged. Alternatively, the supporting arm (32) extends in the first direction.
8. The fixture of any one of claims 1-6, wherein, The pressing plate (2) is horizontally and spacedly provided with two.
9. The fixture of any one of claims 1-6, wherein, The fixing tool further comprises a supporting block (7) for clamping the workpiece to be welded in cooperation with the pressing piece (33); And / or, the fixing tool comprises a plurality of auxiliary limiting pieces (4), one end of the auxiliary limiting piece (4) is rotatably arranged on the fixing base (1), and the other end can abut the upper side of the pressing plate (2).
10. The fixture of any one of claims 1-6, wherein, The fixing tool comprises a plurality of limiting sliding blocks (5), and the plurality of limiting sliding blocks (5) are slidably arranged on the circumferential side of the fixing base (1) to horizontally press the workpiece to be welded. And / or, the fixing tool further comprises a plurality of threaded jacking pieces (6), the threaded jacking pieces (6) are threadedly arranged on the circumferential side of the fixing base (1) and located below the pressing plate (2) to horizontally press the workpiece to be welded.