Device for installing support ring in bladder skin and method for installing support ring in bladder skin

Abstract

The present invention provides a device for installing a support ring in a bladder skin and a method for installing a support ring in a bladder skin. The installation device is composed of a first bladder skin retaining device and a flanging reset device. The first bladder skin retaining device is coaxially provided with a first opening claw plate and a bladder skin pressing mechanism. The first bladder skin retaining device is used to fix a flanging bladder skin with a double-layer flanging at the front end. The first opening claw plate is provided with a support ring slot. The flanging bladder skin with a double-layer flanging at the front end is placed on a first expansion block, and the rear end of the flanging bladder skin is pressed and fixed by the bladder skin pressing mechanism. The flanging reset device is provided with a second claw plate, and the second claw plate is provided with a plurality of radially retractable second claw blocks. A pull hook is axially fixed on the second claw block, and the pull hook is used to pull out the flanging of the flanging bladder skin with a hard support ring installed inside. The present invention realizes the installation of the support ring into the bladder skin through mechanization, which greatly improves production efficiency and product quality and reduces labor costs.

Description

Technical Field

[0001] The invention relates to air bag processing of an air shock absorber, and in particular to a device for installing a support ring in a bag skin and a method for installing the support ring in the bag skin. Background Art

[0002] Figure 1 The schematic diagram of the existing air shock absorber is shown in FIG. 1 . According to the process requirements, the metal support ring 2 needs to be coaxially installed in the bladder skin 1. The finished product is shown in FIG. Figure 2 In the prior art, the installation of the support ring in the automobile air shock absorber is basically done manually, and the usual operation method is to expand the flat bag and then insert the support ring into the flat bag. This method is not only time-consuming and labor-intensive, but also the manual installation accuracy is not high, which affects the product quality.

[0003] At the same time, since the diameter of the support ring is larger than the inner diameter of the bladder skin, when the difference between the two diameters is relatively large, a large hydraulic pressure is required to expand the bladder skin to successfully install the support ring, which causes relatively large damage to the bladder.

[0004] Therefore, the manufacturer is eager to have a device that can fully automatically install the support ring into the bladder skin. Summary of the invention

[0005] The present invention provides a device for installing a support ring in a bladder skin, the device being used for installing a hard support ring whose outer diameter is larger than the inner diameter of the bladder skin in the bladder skin, the device being composed of a first bladder skin retaining device and a flanging reset device, the first bladder skin retaining device and the flanging reset device being coaxial and relatively sliding;

[0006] The first bladder skin retaining device is used to fix the flanged bladder skin with a double-layer flange at the front end. The first bladder skin retaining device is coaxially provided with a first opening claw disk and a bladder skin pressing mechanism. The first opening claw disk is provided with a plurality of radially retractable first claw blocks. A first expansion block is fixed on the end surface of each first claw block. A supporting ring groove is provided on the outer diameter of the end of the first expansion block along the circumference of the first opening claw disk. The flanged bladder skin with a double-layer flange at the front end is sleeved on the first expansion block, and the rear end of the flanged bladder skin is pressed and fixed by the bladder skin pressing mechanism.

[0007] A second claw plate coaxial with the first expansion block is provided at one end of the flange resetting device close to the first bladder skin retaining device. The second claw plate is provided with a plurality of radially retractable second claw blocks. A pull hook is axially fixed on the second claw block, and the pull hook is used to pull down the flange of the flanged bladder skin with a hard support ring installed inside.

[0008] Furthermore, the bladder skin inner support ring installation device also includes a second bladder skin retaining device with relative sliding movement and a bladder skin extrusion and flanging device, which is used to flanging one end of the stretched bladder skin without flanging to form the flanging bladder skin;

[0009] The second bladder skin retaining device and the bladder skin extrusion flanging device are respectively provided with a coaxial third opening claw plate and a fourth claw plate, the third opening claw plate is provided with a plurality of radially telescopic third claw blocks, a second expansion block is fixed on the end surface of the third claw block, the fourth claw plate is provided with a bladder skin support column and a plurality of radially telescopic fourth claw blocks arranged around the periphery of the bladder skin support column, and a splint is provided on the fourth claw block;

[0010] After the fourth claw plate clamps the unflanged bladder skin and moves it so that the unflanged bladder skin is completely inserted into the second expansion block, the second expansion block expands the aperture of the unflanged bladder skin, and then the fourth claw plate continues to move toward the third expansion claw plate, so that the front end of the unflanged bladder skin is squeezed by the end face of the third claw block and then flanged to form the flanged bladder skin.

[0011] Furthermore, the flanged bag skin is transported by a transport device and inserted into the first opening claw plate.

[0012] Furthermore, a ball or a roller is provided at the front end of the second expansion block.

[0013] Furthermore, the first bladder skin retaining device is also provided with a flanged pushing mechanism, which includes a push rod fixed on each first claw block and axially retractable, a gap is left between the push rod and the first expansion block in the radial direction, and the push rod extends between the two layers of the flanged bladder skin sleeved on the first expansion block;

[0014] A ball or roller is arranged at the front end of the push rod.

[0015] Furthermore, the bladder skin pressing mechanism includes a plurality of pressing blocks arranged around the periphery of the first expansion block, and the pressing blocks are provided with grooves for the flanging pushing mechanism to pass axially.

[0016] A method for installing a support ring in a capsule skin comprises the following steps:

[0017] Take the unflanged bladder skin, and flanging one end of the unflanged bladder skin to form the flanged bladder skin;

[0018] Insert the flanged bladder skin onto the first expansion block, and place the support ring onto the support ring slot of the first expansion block;

[0019] The first expansion block moves radially away from the axis until the inner ring of the support ring contacts the inner side of the support ring groove of each first expansion block, and at the same time expands the aperture of the flanged bladder skin;

[0020] The first capsule skin retaining device slides toward the flange resetting device, and the second claw block contracts radially, so that the draw hook is stuck on the edge of the outer flange;

[0021] The draw hook is axially away from the first bladder skin retaining device to pull down the outer flanging of the flanging bladder skin.

[0022] The above method further comprises:

[0023] A push rod is inserted between the two layers of the flanged bladder skin on the first expansion block. When the hook pulls the outer flange, the push rod slides axially toward the hook to push the outer flange toward the hook.

[0024] A method for installing a support ring in a bladder skin, the method comprising the steps of flanging the bladder skin and installing the support ring in the flanging bladder skin,

[0025] The steps for flanging the capsule skin are as follows:

[0026] S11, take the unflagged bladder skin and insert it on the bladder skin support column and fix it with a clamp;

[0027] S12, the fourth claw plate drives the unflanged bag leather cover onto the second expansion block;

[0028] S13, the second expansion block expands to open the unflanged bladder skin outward, and then the fourth claw plate continues to move toward the third opening claw plate, so that the front end of the unflanged bladder skin is squeezed by the end surface of the third claw block and then flanging to form the flanging bladder skin;

[0029] To install the support ring in the flanged bladder, follow these steps:

[0030] S21, inserting the flanged bladder skin onto the first expansion block, and placing the support ring onto the support ring slot of the first expansion block;

[0031] S22, the first expansion blocks move radially away from the axis until the inner ring of the support ring contacts the inner side of the support ring groove of each first expansion block, and at the same time, the aperture of the flanged bladder skin is expanded;

[0032] S23, the first bag skin retaining device slides toward the flange resetting device, and the second claw block contracts radially, so that the draw hook is stuck on the edge of the outer flange;

[0033] S24, the retractor moves away from the first bladder skin retaining device in the axial direction, and pulls down the outer flange of the flanged bladder skin.

[0034] The beneficial effects of the present invention are as follows:

[0035] 1) The support ring is installed into the bladder skin through mechanization, which greatly improves production efficiency and product quality and reduces labor costs;

[0036] 2) A new method of flanging, installing a support ring, and straightening the flanging is proposed, and the bladder skin is expanded twice in the process of flanging and installing the support ring, which is convenient for flanging and installing the support ring. At the same time, the flanging is performed first and then the support ring is installed. The axial installation depth of the support ring in the bladder skin is deeper, which prevents the support ring from being too close to the bladder skin opening and causing it to fall out;

[0037] 3) Install the support ring after flanging, so that the bladder can be installed with minimal deformation. For products where the inner support ring is much larger than the inner diameter of the bladder, a mechanized installation solution is provided;

[0038] 4) After the first expansion block is expanded, the support ring is fixed by the support ring slot at the front end, and after being inserted, it is contracted to ensure the installation position accuracy of the support ring in the bladder skin;

[0039] 5) The flange can be pulled down only with the help of a pull hook. In addition, the push rod of the flange pushing mechanism can be further used to provide assistance to the pull hook, thereby pulling down the flange more effortlessly. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0041] Figure 1 A schematic diagram of a bladder skin and a support ring that needs to be installed in the bladder skin;

[0042] Figure 2 The finished product diagram is to install the support ring into the bladder skin;

[0043] Figure 3a-Figure 7 This is a flow chart of flanging the capsule skin according to the present invention, wherein:

[0044] Figure 3a It is a schematic diagram of the second bladder skin retaining device and the bladder skin extrusion and flanging device when the bladder skin is not clamped, and the structure of the second bladder skin retaining device is emphasized;

[0045] Figure 3b It is a partial structural schematic diagram of the second capsule skin retention device;

[0046] Figure 3c for Figure 3a A schematic diagram from another perspective, emphasizing the structure of the bag skin extrusion and flanging device;

[0047] Figure 4a A schematic diagram of a bladder skin extrusion and flanging device clamping a bladder skin without flanging;

[0048] Figure 4b for Figure 4a A schematic diagram of a bladder skin extrusion and flanging device holding an unflanged bladder skin from another perspective;

[0049] Figure 5A schematic diagram of the bladder skin extrusion and flanging device driving the unflanged bladder skin to move toward the second bladder skin retaining device;

[0050] Figure 6 This is a schematic diagram of the bag skin after flanging;

[0051] Figure 7 A schematic diagram of the bladder skin extrusion and flanging device driving the flanging bladder skin to exit;

[0052] Figure 8 It is a schematic diagram of the turned-edge bag skin;

[0053] Figure 9-13 This is a flow chart of installing the support ring into the bladder skin according to the present invention, wherein:

[0054] Fig. 9 It is a schematic diagram of the first bladder skin retaining device and the flanging resetting device, emphasizing the structure of the first bladder skin retaining device;

[0055] Fig.10 for Fig. 9 An enlarged schematic diagram of the dashed box in the middle;

[0056] Fig.11 A schematic diagram of the flap skin and the support ring on the first skin retention device;

[0057] Fig.12 This is a schematic diagram of the first expansion block of the first bladder skin retaining device expanding the flap bladder skin;

[0058] Fig.13 A schematic diagram of a draw hook of a flange reset device being stuck on the edge of an outer flange;

[0059] Fig.14 for Fig.13 An enlarged schematic diagram of the dashed box in the middle;

[0060] Fig.15 This is a schematic diagram of the flanged bladder skin after being expanded by the first expansion block. DETAILED DESCRIPTION

[0061] In the following description, a large number of specific details are provided to provide a more thorough understanding of the present invention. However, it is apparent to those skilled in the art that the present invention can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present invention, some technical features well known in the art are not described.

[0062] In order to fully understand the present invention, detailed steps and detailed structures will be proposed in the following description to illustrate the technical solution of the present invention. The preferred embodiments of the present invention are described in detail below, but in addition to these detailed descriptions, the present invention may also have other implementations.

[0063] The present invention provides a device for installing a support ring inside a bladder skin. After flanging one end of the bladder skin at a bladder skin flanging station, the flanging bladder skin is transferred to a support ring installation station to complete the installation of a metal ring inside the bladder skin.

[0064] The following is an explanation of the structure and workflow of the bladder skin flanging station and the support ring installation station:

[0065] Bag flanging station

[0066] like Figure 3a-Figure 7 As shown, the skin flanging station includes a second skin retaining device 100 and a skin extrusion flanging device 200 that slide relative to each other. The second skin retaining device 100 and the skin extrusion flanging device 200 slide relative to each other. As shown in the figure, the second skin retaining device 100 is fixed on the track, while the skin extrusion flanging device 200 can be moved closer to or away from the second skin retaining device 100 on the track. Of course, it can also be set that the skin extrusion flanging device 200 is fixed and the second skin retaining device 100 is slidably arranged on the track.

[0067] The second bladder skin retaining device 100 and the bladder skin extrusion and flanging device 200 are respectively provided with a coaxial third opening claw plate 110 and a fourth claw plate 210, and the third opening claw plate 110 is provided with a plurality of radially telescopic third claw blocks 111 (such as Figure 3a and Figure 3b ), a second expansion block 112 is fixed on the end surface of the third claw block 111, a fourth claw plate 210 is provided with a bladder skin support column 213 and a plurality of radially telescopic fourth claw blocks 211 arranged around the outer periphery of the bladder skin support column 213, and a clamping plate 212 (such as Figure 3c ).

[0068] The steps for flanging the capsule skin are as follows:

[0069] S11, take the unflanged bladder skin 10 and insert it on the bladder skin support column 213, then the fourth claw block 211 contracts to clamp the unflanged bladder skin 10. Figure 4a and Figure 4b shown.

[0070] S12, the bladder skin extrusion and flanging device 200 slides toward the second bladder skin retaining device 100, so that the unflanged bladder skin 10 is completely covered with the second expansion block 112, as shown in FIG. Figure 5 shown.

[0071] S13, the second expansion block 112 expands the inner diameter of the front end of the unflanged bladder skin 10 close to the second bladder skin retaining device 100 outward, and then the bladder skin extrusion flanging device 200 continues to move toward the second bladder skin retaining device 100. Since the inner diameter of the front end of the unflanged bladder skin 10 is expanded by the second expansion block 112 while the rear end is not expanded, when the bladder skin extrusion flanging device 200 drives the unflanged bladder skin 10 to continue forward, the front end of the unflanged bladder skin 10 is squeezed by the end face of the third claw block 111 to flanging backward to form Figure 8 The cuff skin 20 is shown.

[0072] It should be noted that in order to ensure that the bladder skin can be smoothly flanged, the length of the bladder skin needs to be greater than the length of the second expansion block 112, otherwise the bladder skin cannot be flanged even if the second bladder skin retaining device 100 collides with the bladder skin extrusion and flanging device 200.

[0073] In an optional embodiment, a ball or roller 113 is provided at the front end of the second expansion block 112 to make the sliding cooperation between the bladder skin and the second expansion block 112 smoother.

[0074] After processing the flanged bladder skin 20, we transfer the flanged bladder skin 20 on the second bladder skin retaining device 100 through a transfer device (such as a robot) or manually and insert it into the first opening claw plate 310 to perform the subsequent operation of installing the support ring in the bladder skin.

[0075] Inner bladder support ring installation device

[0076] Reference Figure 9-13 As shown, the inner support ring of the bladder skin is composed of a first bladder skin retaining device 300 and a flanging resetting device 400. The first bladder skin retaining device 300 and the flanging resetting device 400 are coaxial and slide relative to each other.

[0077] The first bladder skin retaining device 300 is coaxially provided with a first opening claw plate 310 and a bladder skin pressing mechanism 330. The first opening claw plate 310 is provided with a plurality of radially retractable first claw blocks, and a first expansion block 311 is fixed on the end surface of each first claw block. A support ring clamping groove 312 is provided at the outer diameter of the end of the first expansion block 311 along the circumference of the first opening claw plate 310. The flanged bladder skin 20 with a double-layer flange at the front end is sleeved on the first expansion block 311, and the bladder skin pressing mechanism 330 presses and fixes the single-layer bladder skin at the rear end of the flanged bladder skin 20.

[0078] A second claw plate coaxial with the first expansion block 311 is provided at one end of the flange resetting device 400 close to the first bladder skin retaining device 300, and the second claw plate is provided with a plurality of radially retractable second claw blocks, on which a pull hook 411 is axially fixed, for pulling down the flange of the flanged bladder skin 20 with a hard support ring 30 installed inside.

[0079] In an optional embodiment, the first capsule skin retaining device 300 is further provided with a flange pushing mechanism 320, such as Fig.10 As shown, the flanging pushing mechanism 320 includes a push rod 321 fixed on each first claw block and axially retractable, and a gap is left between the push rod 321 and the first expansion block 311 in the radial direction. The push rod 321 extends between the two layers of the flanging bladder skin 20 sleeved on the first expansion block 311.

[0080] Fig.15 This is a schematic diagram of the flanged bladder skin 20 after being stretched open by the first expansion block 311. The function of the flanged bladder pushing mechanism 320 is: by inserting the push rod 321 between the outer flange 21 of the flanged bladder skin 20 and the lower bladder skin, on the one hand, the contact area of ​​the two layers of bladder skin is reduced, thereby reducing the friction force on the outer flange 21 when being pulled, making it easier for the outer flange 21 to be pulled down; on the other hand, the push rod 321 can slide toward the direction of the pull hook 411, thereby pushing the outer flange 21 to move toward the pull hook, further allowing the outer flange 21 to be easily pulled down.

[0081] In an optional embodiment, the bladder skin clamping mechanism 330 includes a plurality of clamping blocks 331 arranged around the periphery of the first opening claw plate 310. The clamping blocks 331 are used to clamp the inner side of the flanged bladder skin 20 and are provided with a groove 332 for the flanged pushing mechanism 320 to pass axially to avoid interference.

[0082] In an optional embodiment, a ball or roller 323 is provided at the front end of the push rod 321 to make the sliding cooperation between the bladder skin and the push rod 321 smoother.

[0083] The steps to install the support ring in the bladder are as follows:

[0084] S1. First, Figure 8 The flanged bladder skin 20 with flanged edges is inserted into the first expansion block 311, and the push rod 321 extends into the gap between the two layers of bladder skins, and then the support ring 30 is hung on the support ring slot 312 of the first expansion block 311, as shown in FIG. Fig.11 It should be noted that, when the push rod 32 is not extended, the push rod 32 does not protrude from the first expansion block 311 , so as to avoid interference between the push rod 32 and the support ring 30 .

[0085] S2, the first expansion block 311 radially expands away from the axis until the inner ring of the support ring 30 contacts the inner side of the support ring groove 312 of each first expansion block 311, so that the inner ring of the support ring 30 is tightly combined with each first expansion block 311, and the aperture of the flanged bladder skin 20 is expanded. Fig.12 shown.

[0086] S3, the first bladder skin retaining device 300 and the flange reset device 400 slide relative to each other, and then the second claw block of the flange reset device 400 contracts radially, so that the draw hook 411 is stuck at the outer flange edge 22 of the flanged bladder skin 20 (see Figure 8 ),like Figure 13-14 shown.

[0087] S4, the first bag skin retaining device 300 slides in opposite directions to the flange reset device 400, and at the same time the push rod 321 is pushed toward the flange reset device 400, so that the outer flange 21 of the flanged bag skin 20 can be easily pulled off under the dual force of the pull hook 411 and the push rod 321.

[0088] Finally, the first capsule skin retaining device 300 and the flanged edge restoring device 400 are reset, and the flanged edge capsule skin 20 loses its expansion force and begins to shrink under the action of its own elasticity, and then is removed. Figure 2 The finished product flanged bladder skin 2 is shown.

[0089] The above describes the preferred embodiments of the present invention. It should be understood that the present invention is not limited to the above-mentioned specific embodiments, and the devices and structures that are not described in detail should be understood to be implemented in a common manner in the art; any technician familiar with the art can use the above-disclosed methods and technical contents to make many possible changes and modifications to the technical solutions of the present invention without departing from the scope of the technical solutions of the present invention, or modify them into equivalent embodiments of equivalent changes, which does not affect the essential content of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention are still within the scope of protection of the technical solutions of the present invention.

Claims

1. A device for installing a support ring in a bladder skin, the device being used to install a hard support ring having an outer diameter greater than an inner diameter of the bladder skin in the bladder skin, characterized in that: The installation device is composed of a first bladder skin retaining device (300) and a flanged edge resetting device (400), wherein the first bladder skin retaining device (300) and the flanged edge resetting device (400) are coaxial and relatively slidable; The first bladder skin retaining device (300) is used to fix the flanged bladder skin (20). The first bladder skin retaining device (300) is coaxially provided with a first opening claw plate (310) and a bladder skin pressing mechanism (330). The first opening claw plate (310) is provided with a plurality of radially retractable first claw blocks. A first expansion block (311) is fixed on the end surface of each first claw block. A supporting ring groove (312) is provided on the outer diameter of the end of the first expansion block (311) along the circumference of the first opening claw plate (310). The flanged bladder skin (20) with a double-layer flange at the front end is sleeved on the first expansion block (311), and the rear end of the flanged bladder skin (20) is pressed and fixed by the bladder skin pressing mechanism (330). A second claw plate is provided at one end of the flanged bladder skin (400) close to the first bladder skin retaining device (300), and the second claw plate is provided with a plurality of radially retractable second claw blocks, and a draw hook (411) is axially fixed on the second claw block, and the draw hook (411) is used to pull down the flanged bladder skin (20) with the support ring (30) installed therein; The installation device further comprises a second bladder skin retaining device (100) that slides relatively and a bladder skin extrusion and flanging device (200) that is used to flanging one end of the stretched bladder skin (10) without flanging to form the flanging bladder skin (20); The second bladder skin retaining device (100) and the bladder skin extrusion and flanging device (200) are respectively provided with a coaxial third opening claw plate (110) and a fourth claw plate (210); The third spreading claw plate (110) is provided with a plurality of radially retractable third claw blocks (111), and a second expansion block (112) is fixed on the end surface of the third claw block (111). The fourth claw plate (210) is provided with a bladder skin support column (213) and a plurality of radially retractable fourth claw blocks (211) arranged around the periphery of the bladder skin support column (213), and a clamping plate (212) is provided on the fourth claw block (211).

2. The device for installing the support ring in the bladder skin as claimed in claim 1, characterized in that: The flanged bag skin (20) is transported by a transport device and inserted onto the first opening claw plate (310).

3. The device for installing the support ring in the bladder skin as claimed in claim 2, characterized in that: A ball or a roller is provided at the front end of the second expansion block (112).

4. The device for installing a support ring in a bladder skin as claimed in claim 1, characterized in that: The first bladder skin retaining device (300) is also provided with a flanged pushing mechanism (320), the flanged pushing mechanism (320) comprising a push rod (321) fixed on each first claw block and axially retractable, a gap being left between the push rod (321) and the first expansion block (311) in the radial direction, and the push rod (321) extending between two layers of the bladder skin (20) sleeved on the first expansion block (311); A ball or a roller is provided at the front end of the push rod (321).

5. The device for installing the support ring in the bladder skin as claimed in claim 4, characterized in that: The bladder skin pressing mechanism (330) comprises a plurality of pressing blocks (331) arranged in a ring around the periphery of the first expansion block (311), and the pressing blocks (331) are provided with grooves (332) for the flanging pushing mechanism (320) to pass axially.

6. A method for installing a support ring in a bladder skin based on the device for installing a support ring in a bladder skin according to any one of claims 1 to 5, characterized in that: The steps include: Take an unflanged bladder skin (10), and flanging one end of the unflanged bladder skin (10) to form the flanged bladder skin (20), and the steps of flanging the bladder skin are as follows: S11, take the unflanged bladder skin (10), insert it on the bladder skin support column (213), and press and fix it with the clamping plate (212); S12, the fourth claw plate (210) drives the unflanged bladder skin (10) to be sleeved on the second expansion block (112); S13, the second expansion block (112) expands to open the unflanged bladder skin (10) outward, and then the fourth claw plate continues to move toward the third opening claw plate (110), so that the front end of the unflanged bladder skin (10) is squeezed by the end surface of the third claw block (111) and then flanging to form the flanged bladder skin (20); Inserting the flanged bladder skin (20) onto the first expansion block (311), and placing the support ring (30) onto the support ring slot (312) of the first expansion block (311); The first expansion block (311) moves radially away from the axis until the inner ring of the support ring (30) contacts the inner side of the support ring groove (312) of each first expansion block (311), and at the same time expands the aperture of the flanged bladder skin (20); The first capsule skin retaining device (300) slides toward the flange resetting device (400), and the second claw block contracts radially, so that the draw hook (411) is stuck on the edge (22) of the outer flange; The pull hook (411) moves away from the first bladder skin retaining device (300) in the axial direction, and pulls down the outer flange (21) of the flanged bladder skin (20).

7. The method according to claim 6, characterized in that The method further comprises: A push rod (321) is inserted between two layers of the flanged bladder skin (20) on the first expansion block (311), and while the pull hook (411) pulls the outer flange (21), the push rod (321) slides axially toward the pull hook (411) to push the outer flange toward the pull hook (411).

Images