Mandrel for bending pipe

Abstract

The present invention discloses a mandrel for bending pipes, belonging to the technical field of round pipe bending equipment, comprising a draw rod and a plurality of supporting units connected in sequence, wherein the supporting unit at the end is connected to the draw rod, and the supporting unit comprises an outer ring body and an inner ring body, wherein the outer ring body is rotatably mounted on the inner ring body, and the inner ring bodies of two adjacent supporting units are hinged by a hinge seat, and an adjusting mechanism for adjusting the angle of the outer ring body on the inner ring body is arranged in the inner ring body. The plurality of supporting units arranged in the present invention are connected by a hinge seat, so that the adjacent supporting units can rotate around the pin of the hinge seat, so that the outer ring body of the supporting unit can adapt to the bending curvature of the round pipe and support the inner wall of the round pipe at the bend, and the present invention is provided with an adjusting mechanism for adjusting the angle of the outer ring body on the inner ring body, so that when pulling the core, the outer ring body can be rotated by a certain angle, so that most of the spherical surface of the outer ring body is out of contact with the inner wall of the round pipe, thereby greatly reducing the resistance during pulling the core.

Description

Technical Field

[0001] The invention relates to the technical field of round tube bending equipment, and in particular to a mandrel for tube bending. Background Art

[0002] Pipe bending is a common form of processing for round pipes, which refers to bending the round pipe to a certain arc. At present, pipe bending machines are often used to bend round pipes. In order to avoid the concave wrinkles and deformation of the round pipe during the bending process, a mandrel is often used to support the inner wall of the round pipe when bending the pipe. The common mandrel is composed of a plurality of round balls hinged in sequence. In order to facilitate the insertion and extraction of the mandrel, the existing round balls are generally smaller than the inner wall of the round pipe, which makes the round balls unable to effectively support the inner wall of the round pipe, and the round pipe will still have a small amount of deformation at the bend; if the diameter of the ball is set to the same as the diameter of the inner wall of the round pipe, there will be greater resistance when inserting and pulling the core.

[0003] To this end, the present invention provides a mandrel for bending a pipe. Summary of the invention

[0004] In view of the above-mentioned technical deficiencies, an object of the present invention is to provide a mandrel for bending pipes, which can reduce the core pulling resistance during core pulling.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solution: The present invention provides a mandrel for bending a pipe, comprising:

[0006] draw rod; and

[0007] A plurality of support units, wherein the plurality of support units are connected in sequence, and the support unit at the end is connected to the draw rod, wherein the support unit comprises an outer ring body and an inner ring body, wherein the outer ring body is rotatably mounted on the inner ring body, and the inner ring bodies of two adjacent support units are hingedly connected through a hinge seat, and an adjustment mechanism for adjusting the angle of the outer ring body on the inner ring body is arranged in the inner ring body;

[0008] During the pipe bending process, the axis of the outer ring body is tangent to the center line of the corresponding position of the round tube; when the core shaft is pulled out, the axis of the outer ring body and the center line of the corresponding position of the round tube are out of the tangent state.

[0009] Preferably, the adjustment mechanism comprises:

[0010] A ball, the ball is rotatably mounted in the inner ring, a slide groove is provided on the ball, and a first tooth is provided on the groove wall of the slide groove;

[0011] A limiting post is fixedly connected to the outer ring body and passes through the inner ring body, and a second tooth meshing with the first tooth is arranged at one end of the limiting post close to the sphere.

[0012] Preferably, the adjustment mechanism further comprises a drive shaft, the balls in two adjacent support units are connected via a coupling joint, the drive shaft is rotatably mounted in the draw rod and connected to the adjacent balls via a coupling joint;

[0013] When the driving shaft rotates in the draw rod, the driving shaft drives all the balls to rotate.

[0014] Preferably, the inner ring body comprises two fixedly connected half rings, and opposite sides of the two half rings are each provided with a concave spherical surface cooperating with the sphere.

[0015] Preferably, the hinge seat includes two connecting plates, the two connecting plates are respectively fixedly connected to the half rings on two adjacent supporting units, and the two connecting plates are hinged by a pin.

[0016] Preferably, a fixing plate is provided at one end of the draw rod close to the support unit, a clearance hole is opened on the fixing plate, one connecting plate of the hinge seat is fixed on the fixing plate, and the other connecting plate is fixed on the half ring of the adjacent support unit.

[0017] Preferably, the outer side wall of the outer ring body is a spherical surface, and grooves are provided on the spherical surface at positions corresponding to the two ends of the limiting pillars. A support roller is rotatably installed in the groove, and the curvature of the roller surface of the support roller is adapted to the curvature of the spherical surface.

[0018] Preferably, when the mandrel is pulled out, the axis of the support roller is perpendicular to the center line of the corresponding position of the circular tube.

[0019] The beneficial effects of the present invention are as follows: the multiple support units provided in the present invention are connected by a hinge seat, so that adjacent support units can rotate around the pin shaft of the hinge seat, so that the outer ring body of the support unit can adapt to the bending curvature of the circular tube and support the inner wall of the circular tube at the bend. The present invention is provided with an adjustment mechanism that can adjust the angle of the outer ring body on the inner ring body, so that when pulling the core, the outer ring body can be rotated by a certain angle so that most of the spherical surface of the outer ring body is out of contact with the inner wall of the circular tube, thereby greatly reducing the resistance during core pulling; the support rollers further provided on the outer ring body of the present invention can convert the sliding friction between the outer ring body and the inner wall of the circular tube during core pulling into rolling friction, further reducing the friction and reducing the resistance to core pulling. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, 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 work.

[0021] Figure 1A schematic diagram of the structure of a mandrel for bending a pipe when straightened provided in an embodiment of the present invention.

[0022] Figure 2 It is a schematic diagram of supporting the inner wall of a round tube during the round tube bending process of the present invention.

[0023] Figure 3 It is a schematic diagram of the outer ring body rotating to a certain angle under the action of the adjustment mechanism when the core shaft is pulled out of the present invention.

[0024] Figure 4 It is a stereoscopic diagram of the core shaft of the present invention when the outer ring body rotates a certain angle in a bent state.

[0025] Figure 5 It is a schematic diagram of the top view of a single support unit of the present invention cooperating with a circular tube when its outer ring body rotates a certain angle.

[0026] Figure 6 It is a schematic diagram of the coordination between the outer ring body of a single support unit of the present invention and the front view angle of the inner wall of the circular tube when the outer ring body rotates a certain angle.

[0027] Figure 7 for Figure 5 Cross-sectional view at AA in the middle.

[0028] Figure 8 It is a three-dimensional diagram of the support unit of the present invention.

[0029] Fig. 9 It is a schematic diagram from a top view showing that the outer ring body of a single support unit of the present invention abuts against the inner wall of a circular tube.

[0030] Fig.10 It is a schematic diagram from a front view showing that the outer ring body of a single support unit of the present invention abuts against the inner wall of a circular tube.

[0031] Fig.11 for Fig. 9 Cross-sectional view at the middle BB.

[0032] Description of reference numerals:

[0033] 1. draw rod, 11. drive shaft, 12. coupling joint, 13. fixed plate, 2. support unit, 21. outer ring body, 211. groove, 212. support roller, 22. inner ring body, 221. half ring, 23. sphere, 231. slide groove, 232. first tooth, 233. limit column, 234. second tooth, 3. hinge seat, 31. connecting plate, 32. pin shaft. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] Embodiment 1:

[0036] like Figure 1 and Figure 2 As shown, the first embodiment of the present invention provides a mandrel for bending pipes, comprising a draw rod 1 and six support units 2, the six support units 2 are hinged in sequence through a hinge seat 3, and the support unit 2 at the end is hinged to the draw rod 1 through the hinge seat 3. Since the adjacent support units 2 can rotate through the hinge seat 3, the support units 2 can be rotated like Figure 2 As shown in the figure, the tube is bent one by one in a circular tube.

[0037] like Figure 8 and Fig.11 As shown, the support unit 2 includes an outer ring body 21 and an inner ring body 22, the inner ring body 22 is located inside the outer ring body 21, and a limiting column 233 is fixed to the inner wall of the outer ring body 21, and the limiting column 233 passes through the inner ring body 22. The outer ring body 21 can rotate on the inner ring body 22 with the limiting column 233 as the center. The outer side wall of the outer ring body 21 is a spherical surface, and the diameter of the spherical surface matches the inner diameter of the circular tube to be bent.

[0038] like Figure 2 As shown, during the pipe bending process, the spherical surface of the outer ring body 21 is tangent to the inner wall of the round pipe, and the axis of the outer ring body 21 is tangent to the center line of the corresponding position of the round pipe. In this way, under the support of the outer ring body 21, the round pipe can be prevented from sinking and deforming inward during the pipe bending process.

[0039] like Figure 3 As shown, when the mandrel needs to be pulled out, the adjustment mechanism provided on the inner ring body 22 drives the outer ring body 21 to rotate 45 degrees around the limit column 233, so that the axis of the outer ring body 21 is out of tangency with the center line of the corresponding position of the circular tube. Figure 3 As can be seen from the figure, due to the rotation of the outer ring body 21, most of the spherical surface of its outer wall is out of contact with the inner wall of the circular tube. Figure 6 As shown, when the outer ring body 21 rotates 45 degrees, only the top and bottom of the outer ring body 21 are still in contact with the inner wall of the circular tube, while the remaining parts are out of contact with the inner wall of the circular tube, which greatly reduces the resistance when the core shaft is pulled out, and the core shaft is easily pulled out.

[0040] When in use, the angle of the outer ring body 21 on the inner ring body 22 can be changed through the adjustment mechanism, thereby changing the contact surface between the outer ring body 21 and the inner wall of the circular tube, so that the outer ring body 21 can fully support the inner wall of the circular tube during the bending process, and during the core pulling process, the contact with the inner wall of the circular tube can be reduced, thereby reducing friction and making it easier for the core shaft to be pulled out.

[0041] Embodiment 2:

[0042] On the basis of the first embodiment, the adjustment mechanism designed by the present invention includes a ball 23 rotatably mounted in the inner ring body 22 and a drive shaft 11 rotatably mounted on the draw rod 1. In order to facilitate disassembly and installation, the inner ring body 22 of the present invention includes two half rings 221 fixedly connected by bolts, and the opposite sides of the two half rings 221 are provided with concave spherical surfaces for mounting the ball 23, so that when the bolts lock the two half rings 221, the ball 23 can be limited in the inner ring body 22, and the ball 23 can rotate in the concave spherical surface.

[0043] The hinge seat 3 of the present invention includes two connecting plates 31, and the two connecting plates 31 are hinged by a pin 32. Figure 1 As shown, two connecting plates 31 on the hinge seat 3 between two adjacent support units 2 are respectively fixedly connected to the semi-rings 221 on the two adjacent support units 2. A fixing plate 13 is fixed to one end of the draw rod 1 close to the support unit 2, and a clearance hole for the drive shaft 11 to pass through is opened on the fixing plate 13. One connecting plate 31 of the hinge seat 3 is fixed to the fixing plate 13, and the other connecting plate 31 is fixed to the semi-ring 221 of the support unit 2 adjacent to the draw rod 1.

[0044] like Fig.11 As shown, a slide groove 231 is provided on the sphere 23, and a first tooth 232 is provided on the groove wall of the slide groove 231, and a second tooth 234 meshing with the first tooth 232 is provided on one end of the limiting column 233 that passes through the inner ring body 22 and is located in the slide groove 231. Therefore, when the limiting column 233 is displaced in the slide groove 231, the first tooth 232 cooperates with the second tooth 234 to drive the limiting column 233 to rotate relative to the sphere 23.

[0045] The balls 23 in two adjacent support units 2 are connected by a coupling 12, which is a universal joint that can transmit torque, and can also be called a coupling. At the same time, the drive shaft 11 is also connected to the adjacent balls 23 by a coupling 12. Therefore, when the drive shaft 11 is rotated, all the balls 23 can be driven to rotate through multiple couplings 12, while the inner ring body 22 cannot be driven to rotate by the drive shaft 11 under the action of the hinge seat 3, so that the balls 23 can drive the limit column 233 to rotate through the meshing of the first teeth 232 and the second teeth 234, so as to achieve Figures 2 to 3The outer ring body 21 shown rotates at a certain angle, so that the state of the outer ring body 21 changes from supporting the inner wall of the round tube to reducing the friction with the inner wall of the round tube, thereby facilitating core pulling.

[0046] Embodiment three:

[0047] On the basis of the first and second embodiments, the present invention further improves the outer ring body 21. Through the technical solutions of the first and second embodiments, the rotation angle of the outer ring body 21 can be adjusted. However, since the diameter of the spherical surface of the outer wall of the outer ring body 21 is the same as the diameter of the inner wall of the circular tube, the spherical surface positions corresponding to the two ends of the limit column 233 may still conflict with the inner wall of the circular tube during the core pulling process. In order to further reduce the contact resistance with the inner wall of the circular tube during the core pulling process, as shown in FIG. Figures 4 to 11 As shown, the present invention provides a groove 211 at the position corresponding to the two ends of the limiting column 233 on the spherical surface, and a support roller 212 is rotatably installed in the groove 211. Figure 7 and Fig.11 As shown, the roller surface of the support roller 212 is adapted to the spherical surface. In the process of bending the tube, the support roller 212 can also play a role in supporting the inner wall of the round tube. Figure 3 , Figure 5 and Figure 7 As shown, the axis of the support roller 212 will turn into a center line perpendicular to the corresponding position of the round tube, and at this time, only the upper and lower support rollers 212 on the support unit 2 are in contact with the inner wall of the round tube. Since the support rollers 212 are rotatable, rolling friction is mainly manifested during the core pulling process, which greatly reduces the resistance during core pulling and makes the core shaft easier to be pulled out.

[0048] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A mandrel for bending a pipe, characterized in that: include: Pull rod (1); as well as A plurality of support units (2), wherein the plurality of support units (2) are connected in sequence, and the support unit (2) at the end is connected to the draw rod (1), wherein the support unit (2) comprises an outer ring body (21) and an inner ring body (22), wherein the outer ring body (21) is rotatably mounted on the inner ring body (22), and the inner ring bodies (22) of two adjacent support units (2) are hingedly connected via a hinge seat (3), and an adjustment mechanism for adjusting the angle of the outer ring body (21) on the inner ring body (22) is provided in the inner ring body (22); During the pipe bending process, the axis of the outer ring body (21) is tangent to the center line of the corresponding position of the round pipe; when the mandrel is withdrawn, the axis of the outer ring body (21) is out of tangency with the center line of the corresponding position of the round pipe; The regulating mechanism comprises: A spherical body (23), the spherical body (23) being rotatably mounted in the inner ring body (22), the spherical body (23) being provided with a slide groove (231), and a first tooth (232) being provided on a groove wall of the slide groove (231); A limiting column (233) is fixedly connected to the outer ring body (21) and passes through the inner ring body (22); one end of the limiting column (233) close to the spherical body (23) is provided with a second tooth (234) meshing with the first tooth (232).

2. A pipe bending mandrel according to claim 1, characterized in that: The adjustment mechanism further comprises a drive shaft (11), the balls (23) in two adjacent support units (2) are connected via a coupling joint (12), the drive shaft (11) is rotatably mounted in the draw rod (1) and is connected to the adjacent balls (23) via the coupling joint (12); When the drive shaft (11) rotates inside the draw rod (1), the drive shaft (11) drives all the balls (23) to rotate.

3. A pipe bending mandrel according to claim 1, characterized in that: The inner ring body (22) comprises two fixedly connected half rings (221), and opposite sides of the two half rings (221) are each provided with a concave spherical surface that matches the spherical body (23).

4. A pipe bending mandrel as claimed in claim 3, characterized in that: The hinge seat (3) comprises two connecting plates (31), the two connecting plates (31) being fixedly connected to the half rings (221) on two adjacent support units (2) respectively, and the two connecting plates (31) being hinged via a pin shaft (32).

5. A pipe bending mandrel as claimed in claim 4, characterized in that: A fixing plate (13) is provided at one end of the draw rod (1) close to the support unit (2), and a clearance hole is provided on the fixing plate (13). One connecting plate (31) of the hinge seat (3) is fixed on the fixing plate (13), and the other connecting plate (31) is fixed on the half ring (221) of the adjacent support unit (2).

6. A pipe bending mandrel according to claim 1, characterized in that: The outer wall of the outer ring body (21) is a spherical surface, and grooves (211) are provided on the spherical surface at positions corresponding to the two ends of the limiting pillars (233). A support roller (212) is rotatably mounted in the groove (211), and the curvature of the roller surface of the support roller (212) matches the curvature of the spherical surface.

7. A pipe bending mandrel as claimed in claim 6, characterized in that: When the mandrel is pulled out, the axis center line of the support roller (212) is perpendicular to the center line of the corresponding position of the circular tube.

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