A lengthening tool for a bending tail of a seamless tube

Abstract

The utility model relates to the technical field of seamless pipe processing, specifically to a kind of extension tooling for the insufficient length of seamless pipe bending tail part, including internal thread filling column, extension column, clamping block and locking part, and the filling portion of internal thread filling column is equipped with the external thread matched with the internal thread of seamless pipe, and the connecting portion is equipped with non-circular boss;Extension column one end is equipped with the installation slot matched with boss, and the other end is equipped with the second positioning slot with the width of 4mm;Clamping block is embedded in the clamping slot of filling portion, for preventing rotation;Locking part is M12 bolt, and the through hole of extension column is connected with internal thread hole by screw thread connection.The utility model tooling effectively extends clamping length, prevents internal thread deformation, and ensures bending positioning consistent.

Description

Technical Field

[0001] This utility model relates to the field of seamless tube processing technology, and in particular to an extension tooling for seamless tubes with insufficient bending tail length. Background Technology

[0002] In industrial manufacturing sectors such as automotive parts and fluid transport pipelines, seamless metal tubes often require multiple bending processes to meet complex spatial layouts and connection requirements. During these processes, the chucks of the bending equipment need to stably clamp the ends of the tube to provide sufficient torque and feed force to complete the bending action.

[0003] In existing technologies, bending can be performed directly on seamless tubes with sufficient tail length. However, when product design requires the final bend to be very close to the tube end, the remaining tail length of the tube after bending is too short. As shown in the specific product addressed in this application, the tail length after the final bend is only 87mm. This excessively short tail length presents two interrelated technical challenges that urgently need to be addressed in actual production:

[0004] First, there is the issue of clamping and positioning failure: Since the length of 87mm is lower than the minimum effective clamping length of the standard bending machine chuck, the chuck cannot firmly grip the end of the pipe fitting. During the bending process, slippage or loose clamping is very likely to occur, resulting in the inability to effectively transmit bending force. This not only makes it impossible to guarantee the bending angle, but may also cause equipment downtime or safety accidents, seriously restricting the continuity of production and the consistency of products.

[0005] Secondly, there is the issue of internal thread deformation: the short-tail seamless tube has pre-machined M33×1.5 precision threads inside. The wall in this area is relatively thin, resulting in lower mechanical strength. When the bending machine chuck applies direct force to the short tail end for bending, the enormous radial force and bending moment act directly on the threaded area, causing irreversible extrusion deformation, tearing, or even collapse of the internal threads. The direct consequence is that during subsequent assembly, bolts cannot be easily screwed in or are difficult to tighten, rendering the product unusable and resulting in an extremely high scrap rate.

[0006] Currently, the industry lacks a dedicated and effective solution for bending such short-tailed seamless tubes with internal threads. Conventional tooling fixtures can only solve the clamping problem but cannot prevent internal thread deformation; while simple internal fillers often cannot simultaneously meet the rigidity requirements of the force transmission extension.

[0007] Publication No.: CN207252324U. A horticultural support post is described, comprising a female and a male end of a metal tube at its first and second ends. The female end includes a hollow cylindrical first connecting portion, coaxial with the metal tube and having internal threads on its inner wall. The male end includes a cylindrical second connecting portion, coaxial with the metal tube and having external threads on its outer wall that match the internal threads. However, in this technical solution, the threaded connection between the male and female ends is only used to extend the post length to accommodate planting height requirements, not for positioning and transmission with the chuck of a bending device, and does not address the protection of the internal threads.

[0008] Publication No.: CN217153780U A type of stainless steel shaped cold-drawn steel pipe includes a steel pipe body, a positioning kit, and a reinforcing core. The reinforcing core is disposed inside the steel pipe body and is fixedly connected to the steel pipe body via a reinforcing support arm. The positioning kit is threaded onto one end of the steel pipe body, and an annular positioning groove is formed at the other end of the steel pipe body. The positioning kit is engaged with the annular positioning groove. However, while the reinforcing core and support arm inside the steel pipe in this technical solution aim to improve the rigidity of the pipe itself, they cannot solve the problem of the pipe's tail being too short to be clamped.

[0009] Therefore, there is an urgent need for an innovative tooling solution that can solve the two major problems of insufficient tail clamping length and internal thread protection during seamless tube bending, ensuring the smooth completion of the bending process and the functional integrity of the final product. Summary of the Invention

[0010] In view of this, the present invention aims to provide an extension tooling for the insufficient tail length when bending seamless tubes, thereby solving the problems of insufficient tail clamping length and internal thread protection during seamless tube bending.

[0011] The invention addresses the specific technological challenge of effectively clamping thin-walled seamless tubes with insufficient tail length and internal threads during bending, and the tendency for internal threads to deform. It proposes a cleverly designed, detachable, and reusable temporary extension fixture. By incorporating an internally threaded filler post precisely matched to the seamless tube's internal threads, the tube is fully screwed into the pipe. This not only ensures a reliable connection but also acts as a rigid inner core during bending, providing full support to the tube wall and effectively preventing internal thread collapse, deformation, or failure due to bending stress concentration. This ensures proper subsequent assembly. A second positioning groove, identical in size to the original tube, at the end of the extension post ensures perfect alignment with the bending chuck's positioning reference, guaranteeing the cumulative accuracy of multiple bending angles. The fixture consists of an internally threaded filler post, an extension post, a clamping block, and locking bolts. Rapid assembly and disassembly are achieved through axial bolt clamping and mechanical engagement. This design effectively extends the clamping length from less than 87mm to over 150mm, meeting the minimum clamping requirements of bending equipment without damaging the product itself. It is suitable for mass production and can be removed after use without affecting the final product shape.

[0012] The technical solution of this utility model is implemented as follows:

[0013] This utility model discloses an extension tooling for seamless tube bending with insufficient tail length, comprising:

[0014] An internal thread filler post includes a filler portion and a connecting portion connected in sequence, wherein the filler portion is provided with an external thread for engaging with the internal thread of a seamless pipe;

[0015] An extension column, one end of which is provided with a mounting groove adapted to the connecting part for connection with the internal thread filling column, and the other end of which forms a clamping part for clamping by a bending device;

[0016] A locking element is used to securely connect the extension post to the internally threaded filler post.

[0017] Furthermore, the connecting part is provided with a boss with a non-circular cross-section.

[0018] Furthermore, the cross-section of the boss is one of a regular polygon, an ellipse, or a circle with a flat key.

[0019] Furthermore, it also includes two locking blocks, which are respectively adapted to the locking slots opened on both sides of the filling part, and the locking blocks are detachably embedded in the locking slots.

[0020] Furthermore, the card block is one of a rectangular block, a trapezoidal block, or a semi-circular block.

[0021] Furthermore, the clamping part is a second positioning groove formed on the outer wall of the extension column, and the width of the second positioning groove is the same as the width of the first positioning groove on the seamless tube body.

[0022] Furthermore, the shape of the mounting groove is adapted to the boss to prevent relative rotation between the extension post and the internal thread filling post.

[0023] Furthermore, the internally threaded filler post has an internally threaded hole along its axial direction.

[0024] Furthermore, the locking element is a bolt, which passes through a through hole on the extension post and is threadedly connected to the internal threaded hole.

[0025] Furthermore, the external thread of the filling part matches the internal thread specification of the seamless tube, and after being screwed in, its end face is flush with or located inside the end of the seamless tube.

[0026] Compared with existing technologies, the extension tooling for seamless tube bending with insufficient tail length according to this utility model has the following advantages:

[0027] 1. This utility model solves the two core problems of inability to clamp and thread deformation when bending short-tail seamless tubes by integrating the dual functions of internal filling support and external clamping extension. It improves protection and operational effectiveness. Compared with traditional single-function fixtures or simple filling solutions, this tooling achieves full-process quality assurance for the workpiece from internal structure to external forming, significantly improving the first-pass yield and product reliability of high-requirement bending processes.

[0028] 2. This utility model achieves rapid clamping and precise positioning between the tooling and the workpiece through the coordinated operation of the internal thread filling column, anti-rotation block, extension column, and locking bolt. The internal thread filling column is directly screwed into the internal thread of the product to achieve precise filling and anti-deformation. The anti-rotation structure formed by its boss and the block ensures the stability of force transmission. The positioning groove of the extension column is consistent with the positioning groove of the product body, ensuring the uniformity of the bending reference. This makes the tooling structure compact, rigid, and more adaptable, and shortens the changeover adjustment time.

[0029] 3. This utility model can complete the tooling installation through standardized steps of screwing in the filling column, embedding the card block, installing the extension column, and tightening the bolt. The process is clear, which greatly reduces the dependence on the operator's skills and shortens the preparation and bending time of a single workpiece, thereby improving the yield rate of the workpiece bending process. Attached Figure Description

[0030] The accompanying drawings, which form part of this utility model, are used to provide a further understanding of the utility model. The illustrative embodiments of the utility model and their descriptions are used to explain the utility model and do not constitute an undue limitation of the utility model. In the drawings:

[0031] Figure 1 This is a front view of the extended tooling assembly structure of this utility model;

[0032] Figure 2 This is a top view of the extended tooling assembly structure of this utility model;

[0033] Figure 3 This is a front view of the internal thread filling post of this utility model;

[0034] Figure 4 This is a top view of the internal thread filling column of this utility model;

[0035] Figure 5 This is a front view of the card block of this utility model;

[0036] Figure 6 This is a top view of the card block of this utility model;

[0037] Figure 7 This is a front view of the extension column of this utility model;

[0038] Figure 8 This is a cross-sectional view of the extension column of this utility model;

[0039] Figure 9 This is a schematic diagram of the structure of the locking component of this utility model;

[0040] Figure 10 This is a front view of the seamless tube of this utility model;

[0041] Figure 11 This is a top view of the seamless tube of this utility model;

[0042] Figure 12 This is a schematic diagram of the structure of the seamless tube after bending according to this utility model.

[0043] Figure label:

[0044] 1. Internal thread filler post; 101. Filler part; 102. Connecting part; 103. Slot; 104. Boss; 105. Internal thread hole; 2. Locking block; 3. Extension post; 301. Mounting groove; 302. Through hole; 303. Second positioning groove; 4. Locking element; 5. Seamless tube; 501. First positioning groove. Detailed Implementation

[0045] To make the technical means and objectives and effects of this utility model easier to understand, the embodiments of this utility model will be described in detail below with reference to specific figures.

[0046] It should be noted that all directional and positional terms used in this utility model, such as "up," "down," "left," "right," "front," "back," "vertical," "horizontal," "inner," "outer," "top," "lower," "lateral," "longitudinal," and "center," are only used to explain the relative positional relationships and connection arrangements between components in a specific state. They are merely for the convenience of describing this utility model and do not require that this utility model be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this utility model. Furthermore, descriptions involving "first," "second," etc., in this utility model are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated.

[0047] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of 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.

[0048] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0049] like Figures 1 to 12 As shown, this utility model provides an extended tooling for solving the problem of ineffective bending when the tail length of a seamless tube is insufficient and it has internal threads. This tooling is particularly suitable for multi-pass bending processes of thin-walled seamless tubes 5 whose tail length is less than the minimum clamping length of the bending equipment chuck. In addition, the tail of the seamless tube 5 has two symmetrically arranged first positioning grooves 501 for positioning the bending chuck of the seamless tube 5.

[0050] Preferably, the internal thread at the tail of the seamless tube 5 is M33×1.5, the length of the tail of the seamless tube 5 that can be used for clamping is 87mm, and the external thread of the internal thread filler post 1 is M33×1.5.

[0051] The extension fixture mainly includes: internal thread filling post 1, extension post 3, locking block 2, and locking element 4.

[0052] The internally threaded filler post 1 has an external thread at one end that matches the internal thread at the tail of the seamless tube 5, allowing it to be completely screwed into the tube. This structure not only achieves a reliable connection with the seamless tube, but more importantly, it acts as a rigid inner core during bending, providing support to the tube wall and effectively preventing collapse or deformation of the internally threaded area due to stress concentration during bending.

[0053] Preferably, the internally threaded filler post 1 includes a filler portion 101 and a connecting portion 102. The filler portion 101 is provided with external threads, and a relief groove is provided between the filler portion 101 and the connecting portion 102 to ensure that the filler portion is completely screwed into the tube. After the filler portion 101 is screwed in, its end face is flush with or slightly inside the end of the seamless tube 5 to ensure continuous and stepless internal cavity support, further improving the thread protection effect.

[0054] The filling part 101 of the internal thread filling column 1 is provided with two symmetrical slots 103. The slots 103 correspond to the first positioning groove 501 at the tail of the seamless tube 5. The slots 103 and the first positioning groove 501 are embedded in the locking block 2 to protect the first positioning groove 501 at the tail of the seamless tube 5 and prevent deformation during bending. Specifically, the locking block 2 can be a rectangular block, a trapezoidal block, or a semi-circular block. Preferably, two rectangular locking blocks are symmetrically arranged on opposite sides of the internal thread filling column 1.

[0055] The connecting part 102 is provided with a boss 104. The cross-section of the boss 104 is designed as a non-circular structure, such as a regular polygon, an ellipse, or a circle with a flat key. Its purpose is to form a circumferential limit with the extension column 3 to prevent the two from rotating relative to each other under the action of bending torque.

[0056] One end of the extension column 3 is provided with a mounting groove 301 that is adapted to the connecting part 102. Its shape perfectly matches the contour of the boss 104 of the connecting part 102, allowing for smooth connection and precise alignment. The other end of the extension column 3 forms a clamping part for clamping by the bending equipment. This clamping part is preferably a second positioning groove 303 opened on the outer wall, with a width of 4mm, which is consistent with the size of the original first positioning groove 501 of the bending chuck on the seamless tube 5 body. This ensures that the tooling and the product are completely consistent in terms of clamping reference, avoiding the cumulative angle error of multiple bends due to positioning deviation.

[0057] To securely connect the extension post 3 to the internally threaded filler post 1, this invention employs a locking component 4 for axial clamping. Specifically, the locking component 4 is an M12 bolt. The internally threaded filler post 1 has an internally threaded hole 105 along the axial direction, and the extension post 3 has a corresponding through hole 302. During assembly, the bolt passes through the through hole 302 and is screwed into the internally threaded hole 105. By tightening, the end face of the extension post 3 is pressed against the end face of the boss 104, forming a rigid integral structure that ensures that no components loosen or shift during high-torque bending.

[0058] In terms of material selection, both the extension column 3 and the internal thread filling column 1 are made of high-strength alloy steel and undergo heat treatment to balance strength, wear resistance, and fatigue resistance, making them suitable for mass production environments. The length of the extension column 3 is determined according to the minimum clamping requirements of the bending machine chuck, and can usually extend the effective clamping length to more than 150mm to meet the clamping needs of various bending machines.

[0059] This invention can also constitute a bending system, including a bending machine, a seamless tube 5 to be bent, and the aforementioned extension fixture. The chuck of the bending machine directly clamps the second positioning groove 303 on the extension column 3, and the bending torque is reliably transmitted to the body of the seamless tube 5 through the fixture.

[0060] Based on the above structure, the specific method of using this utility model is as follows:

[0061] Screw the internal thread filler 1 into the internal thread at the tail of the seamless tube 5, and control the screwing torque within a reasonable range, such as using a torque wrench, to ensure that the end face of the filler 1 is flush with the end of the tube and does not damage the thread.

[0062] Insert the card block 2 into the slot 103 on the internal thread filling post 1;

[0063] The mounting groove 301 of the extension column 3 is fitted onto the boss 104;

[0064] Insert and tighten the locking bolt 4 to complete the tooling assembly;

[0065] Use the bending equipment chuck to clamp the 4mm positioning groove 33 on the extension column 3, and check the axial alignment of the positioning groove with the original positioning groove of the seamless tube body before bending to ensure that the bending center line is consistent.

[0066] Start the bending machine to complete one or more bending operations;

[0067] After bending is completed, loosen bolt 4, and disassemble extension post 3, clamp 2 and internal thread filler post 1 in sequence to obtain a product with intact threads and qualified bending accuracy.

[0068] Furthermore, the extended tooling of this invention is particularly suitable for seamless tube workpieces with a tail length less than the minimum clamping length of the bending machine chuck and internal threads, solving the scrap problem caused by the inability to clamp or thread deformation in traditional processes.

[0069] In summary, this utility model, through its integrated design of internal thread filling support, non-circular boss anti-rotation, extension column clamping, and bolt locking, not only effectively extends the operable length of short-tail seamless tubes but also achieves full protection of the internal thread, while ensuring consistency and repeatability of bending positioning. This tooling structure is simple, easy to assemble and disassemble, and highly versatile, possessing significant practical value and promising prospects for widespread application.

[0070] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. An extension tooling for seamless tubes with insufficient tail length during bending, characterized in that, include: The internal thread filler post (1) includes a filling part (101) and a connecting part (102) connected in sequence. The filling part (101) is provided with an external thread for engaging with the internal thread of the seamless tube (5). An extension column (3) is provided at one end with an installation groove (301) that is adapted to the connecting part (102) for connecting with the internal thread filling column (1), and the other end of the extension column (3) forms a clamping part for clamping the bending equipment. Locking element (4) is used to fix the extension post (3) to the internal thread filling post (1).

2. The extension tooling for insufficient tail length when bending seamless tubes according to claim 1, characterized in that, The connecting part (102) is provided with a boss (104) with a non-circular cross-section.

3. The extension tooling for insufficient tail length when bending seamless tubes according to claim 2, characterized in that, The cross-section of the boss (104) is one of a regular polygon, an ellipse, or a circle with a flat key.

4. The extension tooling for insufficient tail length when bending seamless tubes according to claim 1, characterized in that, It also includes two card blocks (2), which are adapted to the card slots (103) opened on both sides of the filling part (101), and the card blocks (2) are detachably embedded in the card slots (103).

5. The extension tooling for insufficient tail length when bending seamless tubes according to claim 4, characterized in that, The card block (2) is one of a rectangular block, a trapezoidal block, or a semi-circular block.

6. The extension tooling for insufficient tail length when bending seamless tubes according to claim 1, characterized in that, The clamping part is a second positioning groove (303) opened on the outer wall of the extension column (3), and the width of the second positioning groove (303) is the same as the width of the first positioning groove (501) on the body of the seamless tube (5).

7. The extension tooling for insufficient tail length when bending seamless tubes according to claim 2, characterized in that, The shape of the mounting groove (301) is adapted to the boss (104) to prevent relative rotation between the extension post (3) and the internal thread filling post (1).

8. The extension fixture for insufficient tail length of seamless tube bending according to claim 1, characterized in that, The internally threaded filler post (1) has an internally threaded hole (105) along its axial direction.

9. The extension tooling for insufficient tail length when bending seamless tubes according to claim 8, characterized in that, The locking element (4) is a bolt, which passes through the through hole (302) on the extension post (3) and is threadedly connected to the internal threaded hole (105).

10. The extension tooling for insufficient tail length of seamless tube bending according to claim 1, characterized in that, The external thread of the filling part (101) matches the internal thread specification of the seamless tube (5), and after being screwed in, its end face is flush with or located inside the end of the seamless tube (5).

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