Mandrel assembly for pipe bending machine

Abstract

To provide a mandrel assembly capable of improving lubrication of an inside of a tube.SOLUTION: A mandrel assembly for pipe bending machine includes: a mandrel body (21); a mandrel rod; a series of joint elements (24 to 26) connected to each other and to the mandrel body (21) via respective cylindrical or spherical hinges (27 to 28); and a network of lubricant transportation channels (31 to 36) formed so as to penetrate the mandrel body (21) and communicating with a lubricant supply passage formed along the mandrel rod. A plurality of through holes (37) extending along a longitudinal direction of the joint elements (24 to 26) are formed. The through holes (37) are configured to send a lubricant to a front side of the farthest joint element (26) among the series of joint elements (24 to 26). The farthest joint element (26) includes a deflector element (38).SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a mandrel assembly for a pipe bending machine, the mandrel assembly comprising: a mandrel body configured to be inserted inside a tubing to be bent, the mandrel body having a proximal end and a distal end; a mandrel rod rigidly connected to a proximal end of the mandrel body and configured to support and move the mandrel body; a series of articulation elements disposed at a distal end of the mandrel body, each articulation element of the series being connected to an adjacent articulation element of the series via a respective cylindrical or spherical hinge, the series including a proximal-most articulation element connected to the distal end of the mandrel body via a cylindrical or spherical hinge; a network of lubricant transport channels formed through the mandrel body and in communication with the lubricant supply passages formed along the mandrel rod, the network of lubricant transport channels including a plurality of lubricant outlet ports located on at least one of the distal end and the outer circumferential surface of the mandrel body; Equipped with A plurality of through holes are formed through each of the articular elements extending along the length of the articular elements, the through holes being configured to deliver lubricant to a front side of the most distal articular element in the series of articular elements. [Background technology]

[0002] In pipe bending machines, the use of a mandrel assembly is well known as the mandrel assembly serves to internally support the pipe profile during the deformation process and prevent the pipe from wrinkling or ovalizing.

[0003] The fundamental aspect is the formation of a substantial lubricating film in the gap between the mandrel assembly and the inner surface of the piping. Typically, the lubricant (which may have different viscosities) is pumped from a supply system onboard the machine. Summary of the Invention [Problem to be solved by the invention]

[0004] A supply system pumps lubricant through the mandrel rod. The task of distributing the lubricant inside the tube is assigned to lubricant outlet ports in the mandrel body. In more demanding applications, the lubricant dispensed by these ports is insufficient, requiring manual pre-lubrication of the inside of the tubing by the operator.

[0005] Insufficient lubrication can cause parts to overheat and processes to malfunction, putting pipes at risk of bursting.

[0006] The object of the present invention is to provide a solution that allows for improved lubrication of the inside of the tube by the mandrel assembly. [Means for solving the problem]

[0007] This and other objects are fully achieved according to the present invention by virtue of a mandrel assembly having the characteristics defined in the attached independent claim 1.

[0008] Advantageous embodiments of the invention are the subject matter of the dependent claims, the content of which is to be understood as an integral and integral part of the following description.

[0009] In summary, the invention is based on the fact that the most distal articular element comprises a deflector element fixed to the front side of the most distal articular element opposite the respective through-hole, said deflector element being configured to deflect the lubricant exiting the through-hole radially outwards.

[0010] Such a mandrel assembly allows the lubricant from the mandrel body to pass through the through holes formed in the articulation elements, through the space between the mandrel body and the most proximal articulation element, and through the spaces between successive articulation elements until it reaches the front side of the most distal articulation element, thereby improving the distribution of the lubricant.

[0011] This makes the bending process more reliable. Furthermore, the process is more reproducible and the required amount of lubricant is always available. Furthermore, it is a safer process by preventing breakage. Furthermore, it is more economical by eliminating waste. Finally, the process is more economical as manual pre-lubrication is no longer necessary.

[0012] Preferably, each joint element includes a hinge portion at which each joint element of the series of joint elements is connected to an adjacent joint element of the series of joint elements, and a blanket portion attached to and arranged around the hinge portion, the through hole being formed entirely through the blanket portion.

[0013] According to one embodiment, the aforementioned through-holes have a minimum diameter of 4 mm or more, which is recommended when using a high-viscosity lubricating seat, such as a lubricating gel. [Brief explanation of the drawings]

[0014] Further characteristics and advantages of the invention will become apparent from the following detailed description, given purely by way of non-limiting example with reference to the accompanying drawings, in which: [Figure 1] FIG. 1 is a schematic diagram of a pipe bending machine with a mandrel assembly. [Figure 2] FIG. 2 is a perspective view of a mandrel assembly according to the present invention. [Figure 3] 3 is a cross-sectional view of the mandrel assembly of FIG. 2 inserted into a pipe. [Figure 4] FIG. 4 is a cross-sectional view of the mandrel assembly of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] FIG. 1 shows a schematic diagram of an example of a pipe bending machine for processing a pipe T. This pipe bending machine essentially includes a die 10 having a groove on its side surface with a curved path of a predetermined radius about a z-axis perpendicular to the longitudinal axis of the pipe T, a pair of clamp blocks 14, and a bending slide 16 rotatable about the z-axis. Initially, the pipe T is clamped between the clamp blocks 14 and extends forward beyond the die 10 and the bending slide 16. Next, with the pipe T clamped not only between the clamp blocks 14 but also between the die 10 and the bending slide 16, the bending slide 16 is rotated about the z-axis to wrap the pipe T around the die 10, generating a bend in the tube with a mid-radius that substantially corresponds to the mid-radius of the groove in the die 10.

[0016] It will be understood that the present invention is applicable to different types of tube bending machines, and the machines described above are provided as non-limiting examples only.

[0017] The pipe bending machine includes a mandrel assembly, generally designated 20, configured to be inserted inside the pipe T and to internally support the pipe profile during the bending process.

[0018] Mandrel assembly 20 includes a mandrel body 21 configured to be inserted into the interior of piping T. Mandrel body 21 has a proximal end 21 a and a distal end 21 b and is laterally bounded by a circumferential surface 21 c that faces the interior surface of piping T. As used herein, the terms "proximal" and "distal" refer to "nearer" and "farther," respectively, relative to control system A of mandrel assembly 20, which is represented schematically in FIG.

[0019] Mandrel assembly 20 further includes a mandrel rod 23 rigidly connected to proximal end 21 a of mandrel body 21 and configured to support and move mandrel body 21. To this end, mandrel rod 23 is supported by a machine-mounted control system A operable to move the rod along the longitudinal axis of piping T.

[0020] The mandrel assembly 20 further includes a series of articulation elements 24, 25, 26 disposed at the distal end 21b of the mandrel body 21, which are articulated to one another and to the mandrel body 21. These articulation elements 24, 25, 26, commonly known as "balls," are articulated to accommodate deformations of the piping T during the bending process and provide support to the walls of the piping T. While the illustrated example includes three articulation elements, it is understood that the number of articulation elements may vary, e.g., two or more than three. Each articulation element in the series 24-26 is connected to an adjacent articulation element in the series via a respective cylindrical or spherical hinge 28, 29. The most proximal articulation element 24 of the series 24-26 is also connected to the distal end 21b of the mandrel body 21 via a cylindrical or spherical hinge 27.

[0021] More precisely, each articulation element 24-26 comprises a central portion 24a-26a, to which it is connected to the adjacent articulation element 24-26 (forming hinges 28 and 29), and blanket portions 24b-26b attached to and arranged around the central portion 24a-26a. The central portion 24a of the most proximal articulation element 24 is also connected at its distal end 21b to a central insert 21d fixed to the mandrel body 21, thereby forming a hinge 27. Advantageously, the blanket portions 24b-26b may be made of a material different from that of the central portions 24a-26a. For example, the blanket portions 24b-26b may be made of a material having a low coefficient of friction compared to the material of the piping.

[0022] The control system for mandrel assembly 20 includes a lubricant supply system B configured to supply a lubricant, such as a lubricating gel, to mandrel assembly 20 to lubricate the surfaces of mandrel assembly 20 that contact the interior of piping T. To this end, lubricant supply system B includes a pump connected to a lubricant supply passage 23a formed along mandrel rod 23.

[0023] As shown in FIGS. 2 to 4, a network of lubricant transport channels is formed that penetrates the mandrel body 21 and communicates with the lubricant supply passage 23a.

[0024] In the illustrated embodiment, the channel network includes a central manifold 31 formed in the center of the mandrel body 21 and directly communicating with the lubricant supply passage 23a. From the central manifold 31, a plurality of radial channels 32 extend radially toward the circumferential surface 21c of the mandrel body 21. From each radial channel 32, a respective longitudinal channel 33 extends longitudinally toward the distal end 21b of the mandrel body 21, where it opens to the exterior of the mandrel body 21 through a respective lubricant outlet port 34. Furthermore, the radial channels 32 have respective lubricant outlet ports 36 in the circumferential surface 21c, which open to the exterior of the mandrel body 21. These lubricant outlet ports 36 open into at least one surface groove 35 formed in the circumferential surface 21c of the mandrel body 21. In the illustrated example, the surface groove 35 is part of a network of surface grooves formed in the circumferential surface 21c of the mandrel body 21. Some grooves of this network extend in the circumferential direction, while others extend in the longitudinal direction of the peripheral surface 21 .

[0025] A plurality of through holes 37 are formed through each of the joint elements 24 to 26 and extend along the longitudinal direction of each of the joint elements 24 to 26. The through holes 37 are configured to supply lubricant to the front side of the distal-most joint element 26 of the series of joint elements 24 to 26.

[0026] More precisely, the through holes 37 are formed so as to penetrate entirely through the blanket portions 24b to 26b of each of the joint elements 24 to 26. In other words, each of the through holes 37 is completely surrounded by the blanket portions 24b to 26b and does not contact the central portions 24a to 26a. In this way, the through holes 37 can be manufactured in a very simple manner.

[0027] The through-hole 37 may have a minimum diameter of 4 mm or more. Such dimensions are recommended when using a high viscosity lubricant, such as a lubricating gel. However, it is understood that the invention is not limited to this type of lubricant, and that a lower viscosity lubricant, such as oil, may also be used, and therefore the through-hole in the articulation element may have a smaller diameter.

[0028] Advantageously, the most distal articulation element 26 includes a deflector element 38, which includes a surface of revolution 38a with a curved profile fixed to the front side of the most distal articulation element 26 and arranged opposite the respective through-hole 37. The deflector element 38 is configured to deflect the lubricant exiting the through-hole 37 of the most distal articulation element 26 radially outward, which improves the distribution of the lubricant on the inner surface of the pipe T.

Claims

1. 1. A mandrel assembly for a pipe bender, comprising: a mandrel body (21) configured to be inserted inside a pipe (T) to be bent, the mandrel body (21) having a proximal end (21a) and a distal end (21b); a mandrel rod (23) rigidly connected to the proximal end (21a) of the mandrel body (21) and configured to support and move the mandrel body (21); a series of articulation elements (24-26) arranged at the distal end (21b) of the mandrel body (21), each articulation element of the series (24-26) connecting with adjacent articulation elements of the series via respective cylindrical or spherical hinges (28, 29); a series of articulation elements (24-26) connected to the distal end (21b) of the mandrel body (21), the series of articulation elements (24-26) including a proximal-most articulation element (24) connected to the distal end (21b) of the mandrel body (21) via a cylindrical or spherical hinge (27); a network (31-36) of lubricant transport channels formed through the mandrel body (21) and communicating with a lubricant supply passage (23a) formed along the mandrel rod (23), the network (31-36) of lubricant transport channels including a plurality of lubricant outlet ports (34, 36) disposed on at least one of a distal end (21b) and a circumferential surface (21c) of the mandrel body (21); Equipped with a plurality of through holes (37) extending along the longitudinal direction of each of the joint elements (24-26) are formed through each of the joint elements (24-26), the through holes (37) being configured to deliver lubricant to a front side of the distal-most joint element (26) of the series of joint elements (24-26); the most distal articulation element (26) includes a deflector element (38) fixed to a front side of the most distal articulation element (26) opposite each through hole (37), the deflector element (38) being configured to deflect the lubricant exiting each through hole (37) radially outward.

2. each joint element includes a central portion (24a-26a) through which each joint element of the series of joint elements (24-26) is connected to an adjacent joint element of the series of joint elements (24-26), and a blanket portion (24b-26b) attached to the central portion (24a-26a) and arranged around the central portion (24a-26a), and the through-hole (37) is formed entirely through the blanket portion (24b-26b); The mandrel assembly of claim 1 .

3. The through hole (37) has a minimum diameter of 4 mm or more.

3. The mandrel assembly according to claim 1 or 2.

4. the network of lubricant transport channels (31-36) includes a central manifold (31) formed centrally within the mandrel body (21) and in direct communication with the lubricant supply passage (23a), from which branch a plurality of radial channels (32) extending radially toward the circumferential surface (21c) of the mandrel body (21); A mandrel assembly according to any one of claims 1 to 3.

5. a longitudinal channel (33) extending longitudinally toward the distal end (21b) of the mandrel body branches off from each of the radial channels (32) to reach the outside of the mandrel body (21) at the distal end (21b), and has a lubricant outlet port (34) of each of the plurality of lubricant outlet ports (34, 36); The mandrel assembly of claim 4.

6. The radial channel (32) has a lubricant outlet port (36) of each of the plurality of lubricant outlet ports (34, 36) on the circumferential surface (21c) of the mandrel body (21) and leads to the outside of the mandrel body (21).

6. A mandrel assembly according to claim 4 or 5.

7. Each of the lubricant outlet ports (36) leads to at least one surface groove (35) formed in the circumferential surface (21c) of the mandrel body (21). The mandrel assembly of claim 6.

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