A casing positioning welding fixture structure and use method

Abstract

The present application discloses a casing welding fixture and a method of using the same. The welding fixture comprises a base plate, a casing end positioning mechanism, a first positioning mechanism, a second positioning mechanism, a third positioning mechanism, a riser positioning mechanism, a clamp positioning and clamping mechanism, and a bracket. The present application utilizes the basic principle of integrated design. In view of the current difficulty of welding two or more catheter assemblies with different diameters, the small-diameter catheter must be positioned, clamped and welded on a set of tooling, and then the large-diameter pipe must be positioned and pressed on another set of tooling to weld the large-diameter catheter outside. This requires the design and manufacture of two sets of tooling. A set of tooling is designed to weld such catheter assemblies, thereby improving work efficiency. During welding, only the pins and positioning shafts need to be loaded and unloaded on a set of tooling to realize the separate welding of the small-diameter catheter inside and the large-diameter catheter outside. The casings of different diameters can be welded at one time on a set of tooling, thereby reducing the manufacturing cycle, saving costs, and improving efficiency.

Description

Technical Field

[0001] The present application relates to the field of welding technology, and specifically to a sleeve positioning welding fixture structure and a use method. Background Art

[0002] At present, when welding two or more catheter assemblies with different diameters, the existing technology is to design and manufacture two sets of tooling, one set is a special tooling designed for small diameter catheter assemblies, and the other set is a special tooling designed for larger diameter catheter assemblies. In the face of multiple catheter assemblies with different diameters, it is necessary to design many sets of special welding tools with different diameters to meet the use requirements. The welding process is cumbersome, the labor intensity of workers is high, and the product delivery cycle is long.

[0003] In the past, when used on site, the small-diameter catheter could only be positioned, assembled, clamped and welded on a set of tooling. Then the welded small-diameter catheter assembly was removed and repositioned and clamped on another set of tooling to weld the outer large-diameter sleeve catheter. The construction site was occupied by a large number of special clamps, which greatly reduced the welding efficiency. In addition, the designers and manufacturing personnel had to design and manufacture two sets of tooling respectively, and the workers had to clamp multiple times and carry the products back and forth, which was inconvenient to operate and inefficient. Now it is necessary to design a set of tooling that only requires one clamping and welding of such sleeve assemblies in one set of tooling to improve work efficiency, reduce manufacturing cycle and save costs. Summary of the invention

[0004] The purpose of the present application is to design a sleeve positioning welding fixture structure and a use method, wherein the fixture can realize welding of sleeve assemblies of different diameters on a set of tooling.

[0005] In order to achieve the above objectives, this application adopts the following technical solutions:

[0006] A sleeve positioning welding fixture comprises a base plate, a sleeve end positioning mechanism, a first positioning mechanism, a second positioning mechanism, a third positioning mechanism, a riser positioning mechanism, and a tube clamp positioning and clamping mechanism. An angle seat and a sleeve end mechanism are arranged at one end of the base plate. The ends of catheters of different specifications to be welded are fixed on the sleeve end mechanism. The first positioning mechanism, the second positioning mechanism, and the third positioning mechanism are arranged on the base plate in sequence according to the final welding shape of the catheter. The riser positioning mechanism is fixed on the base plate to position the riser part in the catheter. The tube clamp positioning and clamping mechanism clamps the catheter during the catheter welding process. The angle seat supports the other end of the catheter. The third positioning mechanism is supported on the bottom of the catheter during the catheter welding to prevent the catheter from deformation.

[0007] Furthermore, the sleeve end positioning mechanism includes a T-shaped support, a positioning pin, a limit block, and a slot pin. A positioning pin passing hole is provided above the T-shaped support. The limit block is fixed on the positioning pin to support the catheter. The slot pin is fixed on the upper part of the limit block, and its axis is parallel to the axis of the positioning pin. A slot is provided on the outer circle of the top of the slot pin to cooperate with the flange structure on the catheter.

[0008] Furthermore, the first positioning mechanism includes an L-shaped bracket, a first positioning shaft, a semicircular positioning block, two positioning pins, and a small semicircular positioning block. The upper part of the L-shaped bracket is provided with a large semicircular surface matching the shape of the large diameter catheter to be welded, and a through groove is provided in the middle of the surface. The positioning shaft is vertically fixed at the center of the positioning groove, and a small semicircular positioning block is fixed on the top of the positioning shaft. The small semicircular surface matches the shape of the small diameter catheter, and the large and small semicircular surfaces are concentric. One end of the L-shaped bracket vertical plate is provided with a pin matching the flange hole position of the large diameter catheter.

[0009] Furthermore, the second positioning mechanism includes a T-shaped bracket, a second positioning shaft, a semicircular positioning block, a positioning pin, a pressure plate, a clamping nut, and a small semicircular positioning block. The upper part of the T-shaped bracket is provided with a large semicircular surface matching the shape of the large diameter catheter to be welded, and a through groove is provided in the middle of the surface. The positioning shaft is vertically fixed at the center of the positioning groove, and a small semicircular positioning block is fixed on the top of the positioning shaft. The small semicircular surface matches the shape of the small diameter catheter, and the large and small semicircular surfaces are concentric. The upper part of the T-shaped bracket is provided with a supporting plane parallel to the bottom plate, and the supporting plane is provided with bolt holes matching the clamping nut. The pressure plate is supported on the supporting plane and the positioned catheter is clamped by the clamping nut.

[0010] Furthermore, the third positioning mechanism includes a positioning bracket, a third positioning shaft, a small tube positioning block, and a positioning pin. The small tube positioning block is provided with a profile matching the shape of the catheter and is fixed to one end of the third positioning shaft. A third positioning shaft passing hole is provided on the upper part of the positioning bracket. The third positioning shaft is fixedly connected to the T-shaped bracket by a positioning pin.

[0011] Furthermore, the riser positioning mechanism includes a riser support, a fourth positioning axis, a fifth positioning axis, a large conduit positioning block, a branch pipe clamp block, and two positioning pins. The upper and middle parts of the riser support are respectively provided with through holes for the positioning axis. The large conduit positioning block and the branch pipe clamp block are respectively fixed on the same end of the two positioning axes. The semicircular surface of the large conduit positioning block is consistent with the shape of the large conduit, and the semicircular surface of the branch pipe clamp block is consistent with the shape of the riser, and the axes are perpendicular to each other.

[0012] Furthermore, the positioning and clamping mechanism of the tube clamp includes a tube clamp bracket, two cylindrical pins, an upper semicircular pressure plate, a live bolt, and a handle nut. Holes for installing two cylindrical pins are respectively provided on both sides of the vertical plate of the tube clamp bracket. One side of the upper semicircular pressure plate can be flipped on the upper part of the tube clamp bracket through the cylindrical pin. A live bolt is installed on the cylindrical pin at the other end of the tube clamp bracket. The live bolt cooperates with the handle nut to achieve the tightening of the upper semicircular pressure plate.

[0013] Furthermore, a semicircular profile matching the outer shape of the small diameter conduit is formed on the upper portion of the angle seat, and an outer surface of a right angle surface perpendicular to the bottom plate is a reference surface for installing the small diameter conduit.

[0014] The method for using the sleeve positioning welding fixture comprises the following steps:

[0015] 1. First, position the small diameter catheter joint parts on the limit block of the sleeve end positioning mechanism and press against the small diameter catheter end. The first small diameter catheter part is positioned on the small semicircular positioning block of the first positioning mechanism. The second small diameter catheter part is positioned on the semicircular surface of the small semicircular positioning block of the second positioning mechanism and the semicircular surface of the small tube positioning block of the third positioning mechanism and the semicircular surface of the angle seat. The catheter ear piece is sleeved on the first small diameter catheter part. The end face of the catheter ear piece is clamped and positioned on the first small diameter catheter part through the end face of the small semicircular positioning block of the first positioning shaft. After all the small catheter parts are assembled on the fixture, the small diameter catheter is pressed with the upper pressure plate and the clamping nut of the second positioning mechanism, and then welding is started to weld the three sections of small diameter catheter into a small diameter catheter assembly;

[0016] 2 After the welding of the small diameter catheter assembly is completed, remove the small diameter catheter assembly, remove the first positioning shaft and the second positioning shaft of the first positioning mechanism and the second positioning mechanism, put the large diameter catheter part on the welded small diameter catheter assembly, and position the small diameter catheter assembly on the small tube positioning block on the third positioning mechanism. One end face of the small diameter catheter assembly is aligned with the outer surface of the right angle surface of the angle seat perpendicular to the base plate. Use the large diameter semicircular surface of the semicircular positioning block on the first positioning mechanism and the second positioning mechanism to position the large diameter catheter, and position the branch pipe on the large diameter catheter perpendicular to the base plate on the branch pipe block of the riser positioning mechanism, and position the branch pipe on the large diameter catheter parallel to the base plate on the semicircular surface of the clamp holder of the clamp positioning clamping mechanism, so that the assembly positioning of the sleeve assembly on the fixture is accurate, turn over the upper semicircular pressure plate of the clamp positioning clamping mechanism and tighten the nut to compress the large diameter catheter assembly, and then start to weld the large diameter catheter and the small diameter catheter assembly into one.

[0017] The beneficial effect of the present application is that in the past, when used on site, the small-diameter catheter could only be positioned, assembled, clamped and welded on a set of tooling, and then the welded small-diameter catheter assembly could be removed and repositioned and clamped on another set of tooling to weld the outer large-diameter sleeve catheter. The construction site was occupied by a large number of special clamps, which greatly reduced the welding efficiency. In addition, the designers and manufacturers had to design and manufacture two sets of tooling respectively, and the workers had to clamp multiple times and carry the products back and forth, which was inconvenient to operate and inefficient. The present clamp is designed with a set of universal tooling based on the principle of integrated design. Such sleeve assemblies can be clamped and welded only once in a set of tooling, thereby improving the use efficiency, reducing the manufacturing cycle and saving costs. The present device has been actually applied in actual production with good results and good versatility.

[0018] The present application is further described in detail below in conjunction with the accompanying drawings of the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A jacketed conduit positioning welding fixture structure

[0020] Figure 2 End positioning mechanism

[0021] Figure 3 Product image for small diameter catheter

[0022] Figure 4 Casing product assembly diagram

[0023] Figure 5 The first positioning mechanism

[0024] Figure 6 The second positioning mechanism

[0025] Figure 7 The third positioning mechanism

[0026] Figure 8 For the riser positioning mechanism

[0027] Fig. 9 Positioning the clamping mechanism for the tube gripper

[0028] Fig.10 Working diagram of the fixture for welding small diameter pipes

[0029] Fig.11 Working diagram of the fixture for welding large diameter pipes

[0030] Explanation of the numbers in the figure: 1 small diameter conduit joint parts, 2 first small diameter conduit parts, 3 conduit ear pieces, 4 second small diameter conduit parts, 5 large diameter conduit flange joint parts, 6 large diameter conduit, 7 branch pipe on the large diameter conduit perpendicular to the bottom plate, 8 branch pipe on the large diameter conduit parallel to the bottom plate, 9 T-type support, 10 positioning pin, 12 limit block, 13 slot pin, 14 L-type bracket, 15 latch, 16 first positioning shaft, 17 positioning latch, 18 T-type bracket, 19 second positioning shaft, 20 pressure plate, 21 compression nut, 23 The third positioning axis, 24 positioning bracket, 25 small tube positioning block, 27 vertical tube bracket, 28 fourth positioning axis, 29 fourth positioning axis, 30 large conduit positioning block, 31 branch pipe clamp, 32 tube clamp bracket, 33 live bolt, 34 handle nut, 35 cylindrical pin, 36 small semicircular positioning block, 37 upper semicircular pressure plate, 38 casing end positioning mechanism, 39 first positioning mechanism, 40 second positioning mechanism, 41 third positioning mechanism, 42 vertical tube positioning mechanism, 43 tube clamp positioning clamping mechanism, 44 angle seat, 45 bottom plate, 46 semicircular positioning block DETAILED DESCRIPTION

[0031] like Figure 1 As shown in Figure 11, a sleeve positioning welding fixture comprises a base plate 45, a sleeve end positioning mechanism 38, a first positioning mechanism 39, a second positioning mechanism 40, a third positioning mechanism 41, a riser positioning mechanism 42, a tube clamp positioning and clamping mechanism 43, an angle seat 44, and the sleeve end mechanism 38 are arranged at one end of the base plate, and the catheter ends of different specifications to be welded are fixed on the sleeve end mechanism, the first positioning mechanism 39, the second positioning mechanism 40, and the third positioning mechanism 41 are arranged on the base plate in sequence according to the final welding shape of the catheter, the riser positioning mechanism 42 is fixed on the base plate to position the riser part in the catheter, the tube clamp positioning and clamping mechanism 43 clamps the catheter during the catheter welding process, the angle seat 44 supports the other end of the catheter, and the third positioning mechanism 41 is supported on the bottom of the catheter during the catheter welding to prevent the catheter from deformation.

[0032] Furthermore, the sleeve end positioning mechanism 38 includes a T-shaped support 9, a positioning pin 10, a limit block 12, and a slot pin 13. A positioning pin through hole is provided above the T-shaped support 9. The limit block 12 is fixed on the positioning pin 10 to support the small diameter catheter joint part 1. The slot pin 13 is fixed on the upper part of the limit block 12, and its axis is parallel to the axis of the positioning pin 10. A slot that cooperates with the structure of the small diameter catheter joint part 1 is provided on the outer circle of the top of the slot pin 13.

[0033] Furthermore, the first positioning mechanism 39 includes an L-shaped bracket 14, a first positioning shaft 16, a semicircular positioning block 46, a positioning pin 17, a pin 15, and a small semicircular positioning block 36. A large semicircular positioning block 46 matching the shape of the large diameter conduit to be welded is provided on the upper portion of the L-shaped bracket 14, a through groove is provided in the middle portion of the positioning block, the first positioning shaft 16 is vertically fixed at the center of the positioning groove, a small semicircular positioning block 36 is fixed on the top of the first positioning shaft 16, the small semicircular surface matches the shape of the small diameter conduit 2, and the large and small semicircular surfaces are concentric, and a pin 15 matching the hole position of the large diameter conduit flange 5 is provided at one end of the vertical plate of the L-shaped bracket 14.

[0034] Furthermore, the second positioning mechanism 40 includes a T-shaped bracket 18, a second positioning shaft 19, a semicircular positioning block 46, a pressure plate 20, a clamping nut 21, and a small semicircular positioning block 36. A large semicircular positioning block matching the shape of the large diameter conduit to be welded is provided on the upper portion of the T-shaped bracket 18, a through groove is provided in the middle portion of the positioning block, the second positioning shaft 19 is vertically fixed at the center of the positioning groove, a small semicircular positioning block is fixed on the top of the second positioning shaft 19, the profile of the small semicircular positioning block matches the shape of the small diameter conduit, and the large and small semicircular profiles are concentric, a supporting plane parallel to the bottom plate is provided on the upper portion of the T-shaped bracket 18, bolt holes matching the clamping nut 21 are provided on the supporting plane, and the pressure plate 20 is supported on the supporting plane to clamp the positioned conduit through the clamping nut 21.

[0035] Furthermore, the third positioning mechanism 41 includes a positioning bracket 24, a third positioning shaft 23, a small tube positioning block 25, and a positioning pin 17. The small tube positioning block 25 is provided with a profile matching the outer shape of the second small diameter catheter part 4 and is fixed to one end of the third positioning shaft 23. A hole through which the third positioning shaft 23 passes is provided on the upper portion of the positioning bracket 24. The third positioning shaft 23 is fixedly connected to the positioning bracket 24 via the positioning pin 17.

[0036] Furthermore, the riser positioning mechanism 42 includes a riser support 27, a fourth positioning shaft 28, a fifth positioning shaft 29, a large conduit positioning block 30, a branch pipe clamp block 31, and two positioning pins 17. The middle portion of the riser support 27 is provided with a through hole for the fourth positioning shaft 28, and the upper portion of the riser support 27 is provided with a through hole for the fifth positioning shaft 29. The large conduit positioning block 30 and the branch pipe clamp block 31 are respectively fixed at the same end of the two positioning shafts. The semicircular surface of the large conduit positioning block 30 is consistent with the shape of the large conduit, and the semicircular surface of the branch pipe clamp block 31 is consistent with the shape of the riser, and the axes are perpendicular to each other.

[0037] Furthermore, the tube clamp positioning and clamping mechanism 43 includes a tube clamp bracket 32, two cylindrical pins 35, an upper semicircular pressure plate 37, a hinge bolt 33, and a handle nut 34. Holes for installing the two cylindrical pins 35 are respectively provided on both sides of the vertical plate of the tube clamp bracket 32. One side of the upper semicircular pressure plate 37 can be flipped on the upper part of the tube clamp bracket 32 ​​through the cylindrical pin 35. The hinge bolt 33 is installed on the cylindrical pin 35 at the other end of the tube clamp bracket 32. The hinge bolt 33 cooperates with the handle nut 34 to achieve the clamping of the upper semicircular pressure plate 37.

[0038] Furthermore, a semicircular profile matching the outer shape of the second small-diameter conduit part 4 is formed on the upper portion of the angle seat 44 , and an outer surface of a right-angled surface perpendicular to the bottom plate is a mounting reference surface for the second small-diameter conduit part 4 .

[0039] The method for using the sleeve positioning welding fixture comprises the following steps:

[0040] First, position the small diameter conduit joint part 1 on the limit block 12 of the sleeve end positioning mechanism 38 and press the small diameter conduit joint part 1 tightly. The first small diameter conduit part 2 is positioned on the small semicircular positioning block 36 of the first positioning mechanism 39. The second small diameter conduit part 4 is positioned on the semicircular surface of the small semicircular positioning block 36 of the second positioning mechanism 40 and the semicircular surface of the small tube positioning block 25 and the semicircular surface of the angle seat 44 of the third positioning mechanism 41. The conduit ear piece 3 is sleeved on the first small diameter conduit part 2. The end face of the conduit ear piece 3 is clamped and positioned on the first small diameter conduit part 2 through the end face of the small semicircular positioning block 36 of the first positioning shaft 16. After all the small conduit parts are assembled on the fixture, the small diameter conduit is pressed by the upper pressing plate 20 and the clamping nut 21 of the second positioning mechanism 40, and then welding is started to weld the three sections of small diameter conduits into a small diameter conduit assembly;

[0041] After the welding of the small diameter conduit assembly is completed, the small diameter conduit assembly is removed, the first positioning shaft 16 and the second positioning shaft 19 of the first positioning mechanism 39 and the second positioning mechanism 40 are removed, and the large diameter conduit parts are sleeved on the welded small diameter conduit assembly. The small diameter conduit assembly is positioned on the small tube positioning block 25 on the third positioning mechanism 41, and one end face of the small diameter conduit assembly is aligned with the outer surface of the right angle surface of the angle seat perpendicular to the bottom plate, and the large diameter semicircular positioning block 46 on the first positioning mechanism 39 and the second positioning mechanism 40 is used to position the small diameter conduit assembly on the small tube positioning block 25 on the third positioning mechanism 41. The large diameter conduit is positioned by the circular surface, and the branch pipe 7 on the large diameter conduit perpendicular to the base plate is positioned on the branch pipe block 31 of the riser positioning mechanism 42, and the branch pipe 8 on the large diameter conduit parallel to the base plate is positioned on the semicircular surface of the clamp holder 32 of the clamp positioning clamp mechanism 43, so that the sleeve assembly is accurately assembled and positioned on the fixture, the upper semicircular pressure plate 37 of the clamp positioning clamp mechanism 43 is turned over and the handle nut 34 is tightened to compress the large diameter conduit assembly, and then the large diameter conduit and the small diameter conduit assembly are welded together.

[0042] In the past, when using it on site, the small-diameter catheter could only be positioned, assembled, clamped and welded on a set of tooling, and then the welded small-diameter catheter assembly could be removed and repositioned and clamped on another set of tooling to weld the outer large-diameter sleeve catheter. The construction site was occupied by a large number of special clamps, which greatly reduced the welding efficiency. In addition, the designers and manufacturing personnel had to design and manufacture two sets of tooling respectively, and the workers had to clamp many times and carry the products back and forth, which was inconvenient to operate and inefficient. This fixture is designed with a set of universal tooling based on the principle of integrated design. This type of sleeve assembly only needs one clamping and welding in one set of tooling, which improves the use efficiency, reduces the manufacturing cycle and saves costs. This device has been actually applied in actual production with good results and good versatility.

Claims

1. A sleeve positioning welding fixture, characterized in that: It includes a base plate, a casing end positioning mechanism, a first positioning mechanism, a second positioning mechanism, a third positioning mechanism, a riser positioning mechanism, a tube clamp positioning and clamping mechanism, an angle seat and a casing end mechanism are arranged at one end of the base plate, and the catheter ends of different specifications to be welded are fixed on the casing end mechanism. The first positioning mechanism, the second positioning mechanism, and the third positioning mechanism are arranged on the base plate in sequence according to the final welding shape of the catheter. The riser positioning mechanism is fixed on the base plate to position the riser part of the catheter. The tube clamp positioning and clamping mechanism clamps the catheter during the catheter welding process. The angle seat supports the other end of the catheter. The third positioning mechanism is supported on the bottom of the catheter during the catheter welding to prevent the catheter from deforming. The riser positioning mechanism includes a riser support seat, a fourth positioning shaft, a fifth positioning shaft, a large catheter positioning block, a branch pipe clamping block, and two positioning pins. The upper and middle parts of the riser support seat are respectively A through hole for the positioning shaft is provided, and the large catheter positioning block and the branch pipe clamping block are respectively fixed on the same end of the two positioning shafts. The semicircular surface of the large catheter positioning block is consistent with the shape of the large catheter, and the semicircular surface of the branch pipe clamping block is consistent with the shape of the vertical pipe, and the axes are perpendicular to each other. The tube clamp positioning and clamping mechanism comprises a tube clamp bracket, two cylindrical pins, an upper semicircular pressure plate, a live bolt, and a handle nut. Holes for installing two cylindrical pins are respectively provided on both sides of the vertical plate of the tube clamp bracket. One side of the upper semicircular pressure plate can be turned over on the upper part of the tube clamp bracket through the cylindrical pin, and a live bolt is installed on the cylindrical pin at the other end of the tube clamp bracket. The live bolt cooperates with the handle nut to realize the tightening of the upper semicircular pressure plate. A semicircular surface matching the shape of the small diameter catheter is opened on the upper part of the angle seat, and the outer surface of a right-angle surface perpendicular to the bottom plate is the small diameter catheter installation reference surface.

2. A sleeve positioning welding fixture according to claim 1, characterized in that The sleeve end positioning mechanism includes a T-shaped support, a positioning pin, a limit block, and a slot pin. A positioning pin through hole is provided above the T-shaped support. The limit block is fixed on the positioning pin to support the catheter. The slot pin is fixed on the upper part of the limit block, and its axis is parallel to the axis of the positioning pin. A slot is provided on the outer circle of the top of the slot pin to cooperate with the flange structure on the catheter.

3. A sleeve positioning welding fixture according to claim 1, characterized in that The first positioning mechanism comprises an L-shaped bracket, a first positioning shaft, a semicircular positioning block, two positioning pins, and a small semicircular positioning block. A large semicircular surface matching the shape of a large diameter conduit to be welded is provided on the upper portion of the L-shaped bracket, a through groove is provided in the middle of the surface, the positioning shaft is vertically fixed at the center of the positioning groove, a small semicircular positioning block is fixed on the top of the positioning shaft, the small semicircular surface matching the shape of the small diameter conduit, and the large and small semicircular surfaces are concentric, and a pin matching the flange hole position of the large diameter conduit is provided at one end of the L-shaped bracket vertical plate.

4. The sleeve positioning welding fixture according to claim 1 is characterized in that The second positioning mechanism comprises a T-shaped bracket, a second positioning shaft, a semicircular positioning block, a positioning pin, a pressure plate, a clamping nut, and a small semicircular positioning block. A large semicircular profile matching the shape of the large-diameter conduit to be welded is provided on the upper portion of the T-shaped bracket, a through groove is provided in the middle of the profile, the positioning shaft is vertically fixed at the center of the positioning groove, a small semicircular positioning block is fixed on the top of the positioning shaft, the small semicircular profile matching the shape of the small-diameter conduit, and the large and small semicircular profiles are concentric, a supporting plane parallel to the bottom plate is provided on the upper portion of the T-shaped bracket, bolt holes matching the clamping nuts are provided on the supporting plane, and the pressure plate is supported on the supporting plane to clamp the positioned conduit through the clamping nut.

5. The sleeve positioning welding fixture according to claim 1 is characterized in that The third positioning mechanism includes a positioning bracket, a third positioning shaft, a small tube positioning block, and a positioning pin. The small tube positioning block is provided with a profile matching the shape of the catheter and is fixed to one end of the third positioning shaft. A third positioning shaft passing hole is provided on the upper part of the positioning bracket. The third positioning shaft is fixedly connected to the T-shaped bracket by a positioning pin.

6. A method for using a sleeve positioning welding fixture, characterized in that The welding is performed using the fixture described in any one of claims 1 to 5, and the specific process is as follows: 6-1 First, position the small diameter conduit joint parts on the limit block of the sleeve end positioning mechanism and press the small diameter conduit end tightly. The first small diameter conduit part is positioned on the small semicircular positioning block of the first positioning mechanism. The second small diameter conduit part is positioned on the semicircular surface of the small semicircular positioning block of the second positioning mechanism and the semicircular surface of the small tube positioning block and the semicircular surface of the angle seat of the third positioning mechanism. The conduit ear piece is sleeved on the first small diameter conduit part. The end face of the conduit ear piece is clamped and positioned on the first small diameter conduit part through the end face of the small semicircular positioning block of the first positioning shaft. After all the small conduit parts are assembled on the fixture, the small diameter conduit is pressed by the upper pressing plate and the clamping nut of the second positioning mechanism, and then welding is started to weld the three sections of small diameter conduits into a small diameter conduit assembly. 6-2 After the welding of the small diameter catheter assembly is completed, remove the small diameter catheter assembly, remove the first positioning shaft and the second positioning shaft of the first positioning mechanism and the second positioning mechanism, put the large diameter catheter parts on the welded small diameter catheter assembly, and position the small diameter catheter assembly on the small tube positioning block on the third positioning mechanism. One end face of the small diameter catheter assembly is aligned with the outer surface of the right angle surface of the angle seat perpendicular to the base plate. Use the large diameter semicircular surface of the semicircular positioning block on the first positioning mechanism and the second positioning mechanism to position the large diameter catheter, and position the branch pipe on the large diameter catheter perpendicular to the base plate on the branch pipe block of the riser positioning mechanism, and position the branch pipe on the large diameter catheter parallel to the base plate on the semicircular surface of the clamp holder of the clamp positioning clamping mechanism, so that the assembly positioning of the sleeve assembly on the fixture is accurate, flip the upper semicircular pressure plate of the clamp positioning clamping mechanism and tighten the nut to compress the large diameter catheter assembly, and then start to weld the large diameter catheter and the small diameter catheter assembly into one.

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