Method and apparatus for perforating a pipe wall - Patents.com

Abstract

A method and apparatus for perforating a tube wall, comprising: moving the tube longitudinally to a punching position comprising a cutting punch inside the tube and a three-part die. The die is elongated in the direction of movement of the cutting punch by moving the wedge in a first direction of movement towards the free end of the die by a wedge face of the wedge between the die parts. The cutting punch is used to perforate the tube wall, the hole of which is supported by the elongated die during punching, and the pieces punched from the tube fall into the hole in the upper die part. The die is retracted by moving the wedge in a second direction of movement a first distance. The die parts pivot relative to each other in an articulated manner and out of contact with the inner surface of the tube. The perforated tube is moved longitudinally away from the punching position and the tube is moved to a position for finishing the edge of the hole. The lower die part and the wedge are moved together in a second direction of movement a second distance to open the base of the hole and allow the pieces to fall out of the hole.

Description

[Technical Field]

[0001] The present invention relates to a method and apparatus for perforating a pipe wall. Summary of the Invention

[0002] 1. A method for perforating a tube wall with a punch comprising a body, a cutting punch, and a three-piece die having an upper die section, a lower die section, and a wedge between the die sections, the method comprising: moving the die into a punching position inside the tube with the tube longitudinally aligned; extending the die in the direction of movement of a cutting punch by moving a wedge in a first direction of movement toward an end of the die; a step of punching the tube wall with a cutting punch while supporting the tube wall with an extended die, and punched pieces from the tube falling into holes in the upper die portion; retracting the die by moving the wedge in a second direction of movement opposite the first direction of movement; moving the perforated tube longitudinally away from the punching location; and moving the tube into position to finish the edge of the hole.

[0003] An apparatus for perforating a pipe wall, comprising: a body; a cutting punch configured to reciprocate relative to the body and having a desired hole shape and size; an elongated die supported on the body by a support bushing and having a free end, the die comprising an upper die section having a hole corresponding to the shape and size of the cutting punch; a lower die section; and a wedge between the two die sections, the wedge being reciprocable by a first power device to extend and retract the die.

[0004] From US Patent No. 6,128,991 a method and device for punching rectangular cross-section tubes is known, in which the tube is positioned centerline relative to the cutting punch by moving the die part of a two-part die to extend the die laterally relative to the side wall of the tube.

[0005] Japanese Patent Publication No. 11-244957 also discloses a method and apparatus for punching a rectangular tube. A three-part die is extended relative to the inner surface of the tube in the direction of movement of the cutting punch by moving the intermediate die section, with the wedge surface on its lower surface cooperating with the wedge surface on the upper surface of the lowermost die section. The uppermost die section is attached to a body, and the lowermost die section is pivotally supported on the base of the uppermost die section. Below the die, the underside of the tube is supported by the body to receive the punching force of the cutting punch. The reciprocating motion of the intermediate die section serves to extend the die, and the movement distance is limited by the operating range of the wedge surface. Fragments punched from the tube first strike the inner surface of the tube and can damage it when the tube is withdrawn. Furthermore, the die section is dragged along the inner surface of the tube as the tube is pushed into and withdrawn from the punching position. This can also damage the inner surface of the tube.

[0006] When a pipe wall material is to be stretched to create a cylinder or collar within the pipe that branches off from the pipe wall, a suitable pilot hole must first be drilled in the wall from the edge along which the desired cylinder or collar can be stretched. The hole must be of such quality that its edge can withstand the stretching (so-called collaring) required to form the desired collar.

[0007] The quickest known method of creating holes in relatively thin walls is by punching. However, punching does not produce a high enough quality to stretch the branch cylinders and collars. When the material is stretched, it tears at the edges of the holes made by punching.

[0008] Another known method for producing high quality holes for coloring purposes is to machine the holes by milling, which from a manufacturing standpoint is a time-consuming method for producing holes of the desired shape due to the large amount of material that needs to be removed.

[0009] The present invention combines these two known methods of drilling holes by first forming the pilot hole by punching and then finishing the pilot hole by milling. To this end, the present invention has developed a fast and efficient method and apparatus for forming holes by piercing or punching.

[0010] It is an object of the present invention to provide a method and apparatus for efficiently forming pilot holes that meet collaring requirements as an initial process step in the collaring process. The method and apparatus of the present invention should be particularly applicable to piercing round tubes without deforming, scratching, or otherwise damaging the tube.

[0011] This object is achieved by a method according to the appended claim 1. This object is also achieved by an apparatus according to claim 4. The dependent claims disclose preferred embodiments of the invention. [Brief explanation of the drawings]

[0012] [Figure 1] 1 shows a top view of a drilling device according to the present invention; [Figure 2] 2 shows a cross-sectional view taken along line II-II in FIG. [Figure 3] 3 shows a side view of the device according to FIGS. 1 and 2. FIG. [Figure 4] 1 shows a top-view angle of the same device. [Figure 5] 1 shows a diagonal top view of the wedge. [Figure 6A] FIG. [Figure 6B] FIG. 10 is a view of the upper die portion as seen from diagonally below. [Figure 7A] FIG. 2 is a view of the lower die portion viewed from diagonally below. [Figure 7B] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] Embodiments of the present invention will now be described with reference to the accompanying drawings.

[0014] The apparatus includes a body 1 and a cutting punch 2 configured for reciprocating movement relative to the body, the cutting punch having a blade having the desired hole shape and size. Elongated dies 3, 5, 8 are supported on a support bushing 14 attached to the body 1, from which the dies 3, 5, 8 protrude. The dies 3, 5, 8 have free ends from which the tube to be perforated can be forced around the die. The dies 3, 5, 8 include an upper die section 3 having a hole 16 corresponding to the shape and size of the cutting punch, a lower die section 5, and a wedge 8 between the die sections. The wedge 8 is reciprocable in the longitudinal direction of the die by a first power unit 9 to extend or retract the die.

[0015] The tube to be pierced is moved longitudinally into the punching position so that the three-part die 3, 5, 8 is pressed into the tube. The upper die part 3 is the die part on the side of the cutting punch 2. It is attached to a support bush 14 by a swivel joint 4. The swivel joint 4 allows the upper die part 3 to rotate in the direction of movement of the cutting punch 2 within permissible limits by means of the support bush 14 and the wedge 8. Due to this articulation, the cutting punch side of the upper die part 3 is located inside the inner surface of the tube that moves during the pressing phase, without coming into contact with the inner surface of the tube.

[0016] As shown in Figures 6A and 6B, the upper die section 3 comprises an arm 3a having a hole 4a. The swivel joint 4 consists of a cotter bolt passing through the hole 4a. This means that the die section 3 can be easily replaced with another section having a similar arm 3a, but with the actual die section 3 sized to the desired pipe diameter and hole size.

[0017] The lower die part 5 is attached by a swivel joint 6 to a carriage 10 which is moved by a second power unit 12. The swivel joint 6 allows the lower die part 5 to rotate in the direction of movement of the cutting punch 2 within the permissible limits by means of a support bush 14 and a wedge 8.

[0018] As shown in Figures 7A and 7B, the lower die section 5 includes an arm 5a having a hole 6a. The swivel joint 6 consists of a cotter bolt that passes through the hole 6a. The die 6 can therefore be easily replaced with another part having a similar arm 6a, but with the actual die section 5 sized for the desired pipe diameter and hole size.

[0019] As shown in FIG. 5, the wedge 8 has wedge surfaces 8a, 8b on either side. When the first power unit 9 moves the wedge 8 toward the free ends of the dies 3, 5, 8, the wedge surfaces 8a, 8b articulate to move the die sections 3, 5 away from each other, thereby extending the dies. The wedge 8 includes an arm 18 having a hole 7b through which a cotter bolt 7a is inserted, through which a movable section 7 of the power unit 9 (e.g., a piston rod 7 of a piston-cylinder device) is attached to the arm 8a of the wedge 8. Again, the wedge 8 can be easily replaced in conjunction with replacement of the dies 3, 5. The support bushing 14 does not need to be replaced if the size and shape of the die section arms 3a, 5a, 18 and the wedge remain constant.

[0020] The first power unit 9 is configured to move the wedge 8 a first distance in the contraction direction. The second power unit 12 is configured to move the lower die section 5 and the wedge 8 together a second distance, which is an extension of the first distance. The second distance opens the base of the hole 16 in the upper die section 3, allowing the punched pieces to fall. Prior to this, the die was contracted to remove the tube from around the die, so the falling pieces did not damage the inner surface of the tube.

[0021] Arrow 17 indicates a power device, such as a spring, that rotates lower die section 5 upward about the swivel axis formed by swivel joint 6 as wedge 8 moves rearward, i.e., in the retracting direction. Therefore, the lower die section is not dragged along the inner surface of the perforated tube as it is pulled away from the punching position. Upper die section 3 rotates downward due to gravity as the die sections retract.

[0022] The underside of the lower die part 5 has a threshold 15 which is configured to rest against the support bushing 14 at the beginning of the second travel distance and either pivot the lower die part 5 upward or support the lower die part 5 in an already pivoted upward position where the spring 17 is pivoting the die part 5.

[0023] The first power unit 9 is a piston-type cylinder unit. The cylinder is attached to the carriage 10, and the piston rod 7 is attached to the wedge 8 by a cotter bolt 7a. The piston rod 7 and cotter bolt 7a are movable through an opening in the carriage 10. Preferably, the second power unit 12 is also a piston-type cylinder unit. The cylinder is attached to the body 1, and the piston rod is attached to the carriage 10.

[0024] In the illustrated embodiment, the lower surface of the upper die section 3 has a wedge surface that slopes downward toward the free end of the die, where the upper die section 3 thickens toward that end. The upper surface of the lower die section 5 slopes upward, where the lower die section 5 thickens toward its free end. The wedge angle of the wedge surfaces of the die sections 3 and 5 is the same as the wedge angle of the wedge surface of wedge 8. This provides as large a wear surface as possible and a solid die.

[0025] The direction of movement of the carriage 10, and correspondingly of the wedge 8 and lower die section 5, is the same as the direction of tube movement and axial direction. The wedge 8 is on the centerline of the die, and as the power unit 9 moves the wedge 8 towards the free end of the die, it extends the dies 3, 5, 8 symmetrically in the direction of movement of the cutting punch.

[0026] The cutting punch 2 is used to punch holes in the tube wall and is supported by the extended dies 3, 5, and 8 during punching. The broken pieces punched out of the tube fall into the hole 16 in the upper die section 3. When the perforated tube moves to the next processing stage, the broken pieces must not fall into the tube and be dragged along the tube's inner surface or follow the tube. The perforated tube is then moved longitudinally away from the punching position. The tube is then moved to the hole edge finishing position. In this position, the edges of the holes cut by the cutting punch are finished (by chipping) with a rotating blade. The movement of the rotating blade follows the shape of the punched hole. When forming holes in the wall of a round tube to create a branch collar, the shape of the hole is more or less elliptical. In this case, the curvature of the cross sections of the upper and lower surfaces of the dies 3, 5, and 8 also matches the curvature of the inner surface of the round tube. The die width is slightly smaller than the cross section of the tube.

[0027] Before punching a hole, the wedge 8 is moved in a first direction of movement (toward the free end of the die) relative to the die section 3, 5, so that the dies 3, 5, 8 are extended in the direction of movement of the cutting punch 2 by the wedge surfaces 8a, 8b of the wedge 8. During the movement of the wedge 8 and the extension of the dies 3, 5, 8, the dies 3, 5, 8 are supported by the support bush 14. From the support bush 14, the dies 3, 5, 8 extend. At the end of the wedge movement, the wedge surfaces 8a, 8b extend the dies by rotating the upper and lower parts of the dies into contact with the inner surface of the tube. During punching, the punching force is transmitted by the dies 3, 5, 8 to a support structure (not shown) on the opposite side of the tube without flattening the tube.

[0028] After punching, the wedge 8 moves a first distance in a second direction of travel, allowing the die sections 3 and 5 to pivot toward each other in an articulated manner, thereby retracting the die. As the upper die section pivots downward and the spring 17 pivots the lower die section 5 upward, the die is no longer pressed against the tube wall, and the die sections 3 and 5 are no longer in contact with the tube's inner wall. As the tube is pulled away from the punching position, the die no longer contacts the tube's inner surface. A threshold 15 on the underside of the lower die section 5 is configured to rest against the support bushing 14 and to keep the lower die section 5 pivoted upward as the lower die section 5 and the wedge 8 move a second distance. The base of the hole 16 then opens, allowing the punched pieces to fall out of the tube.

[0029] After this, the lower die part 5 and wedge 8 are moved back a second distance by the power unit 12 and carriage 10 towards the free end of the die and the device is ready to receive the next tube to be perforated. The hole 16 is the same size as the cutting punch and the hole formed in the tube for a distance, after which the hole 16 extends conically downwards towards the wedge 8 and lower die part 5, i.e. in the direction of the working movement of the cutting punch 2.

[0030] The first travel distance is preferably shorter than the second travel distance. The carriage 10 is supported on a body (not shown) external to the apparatus by linear bearings 11, to which the body 1 of the apparatus is also attached by a body flange 1a.

Claims

1. A method for perforating a tube wall using a body (1), a cutting punch (2), and a three-part die (3, 5, 8) having an upper die part (3), a lower die part (5) and a wedge (8) between the die parts (3, 5), comprising: moving the tube longitudinally to a punching position where the die (3, 5, 8) is within the tube; extending the die (3, 5, 8) in the direction of movement of the cutting punch by moving the wedge (8) in a first direction of movement towards the end of the die; piercing the tube wall with the cutting punch (2) while supporting the wall with the extended dies (3, 5, 8) during punching, so that pieces punched out of the tube fall into the holes (16) in the upper die section (3); contracting the dies (3, 5, 8) by moving the wedge (8) in a second direction of movement opposite to the first direction of movement; moving the perforated tube longitudinally away from a punching location; and moving the tube into position to finish the edge of the hole; the dies (3, 5, 8) are supported by support bushes (14) attached to the body (1), and the dies (3, 5, 8) are kept out of contact with the inner surface of the tube surrounding the dies during the tube movement; the movement of the wedges in the first direction of movement results in the upper wedge portion pivoting upward and the lower wedge portion pivoting downward, bringing them into contact during extension; after punching, the wedge (8) moves a first distance in the second direction of movement, whereby the die portions (3, 5) are articulated and pivotable towards each other, thereby contracting the dies and moving the perforated tube away from the punching position; the lower die portion (5) and the wedge (8) move together in the second direction of movement a second distance, opening the base of the hole (16) in the upper die portion and allowing the pieces punched out of the tube to fall through the hole (16).

2. 2. The method according to claim 1, wherein at the beginning of the second movement distance in the second direction of movement of the lower die part (5) and the wedge (8), the lower die part (5) is pivoted upward or supported in an upwardly pivoted position by supporting the lower die part on a support bush (14) at a threshold (15) provided on the underside of the lower die part.

3. 3. The method of claim 1 or 2, wherein elliptical holes are formed in the tube wall, which has a circular cross section.

4. 1. An apparatus for perforating a pipe wall, comprising: The cutting punch (2) is configured to reciprocate relative to the body and has a desired hole shape and size; and an elongated die (3, 5, 8) having a free end and supported on the body (1) by a support bush (14), the die (3, 5, 8) comprising an upper die section (3) having a hole (16) corresponding to the shape and size of the cutting punch, a lower die section (5) and a wedge (8) between the die sections, the die sections being reciprocated by a first power unit (9) for extension and contraction, the upper die section (3) being attached to the support bush (14) by a swivel joint (4) which allows the upper die section (3) to rotate in the direction of movement of the cutting punch (2) within allowable limits by the support bush (14) and the wedge (8), and the lower die section (5) being attached to the support bush (14) by a swivel joint (4) which allows the upper die section (3) to rotate in the direction of movement of the cutting punch (2) within allowable limits by the support bush (14) and the wedge (8). the wedge (8) has wedge surfaces (8a, 8b) on either side of the wedge (8) that articulately rotate both die sections (3, 5) away from each other to extend the dies when the first power unit (9) moves the wedge (8) towards the free ends of the dies (3, 5, 8), the first power unit (9) is configured to move the wedge (8) in a contracting direction by a first moving distance, and the second power unit (12) is configured to move the lower die section (5) and the wedge (8) together by a second moving distance that is an extension of the first moving distance, thereby opening the base of the hole (16) in the upper die section (3).

5. 5. The device according to claim 4, wherein the lower surface of the lower die part (5) has a threshold (15) configured to rest against the support bush (14) and to pivot the lower die part (5) upward or to support the lower die part (5) in an upwardly pivoted position at the beginning of the second travel distance.

6. 6. Device according to claim 4 or 5, wherein said first power device (9) is a piston-type cylinder device, the cylinder of which is attached to the carriage (10) and the piston rod of which is attached to said wedge (8).

7. 7. Apparatus according to any one of claims 4, 5 or 6, wherein the second power unit (12) is a piston-cylinder unit, the cylinder of which is attached to the body (1) and the piston rod of which is attached to the carriage (10).

8. 8. Apparatus according to any one of claims 4 to 7, wherein the lower surface of the upper die part (3) has a wedge surface sloping downwards towards the free end of the die, the upper die part (3) thickening towards its end, and the upper surface of the lower die part (5) slopes upwards, the lower die part (5) thickening towards its free end.

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