US20060090531A1

US20060090531A1 - Split die tube bending apparatus

Info

Publication number: US20060090531A1
Application number: US11/263,112
Authority: US
Inventors: Carl Owens
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-11-01
Filing date: 2005-10-31
Publication date: 2006-05-04

Abstract

A tube bending apparatus having an interior bending die about which a tubular segment having fittings on each end that would normally preclude bending to approximately 180 degrees is bent, the interior bending die being separable into two portions along the bending plane, such that the die can be split to release the bent tubular member.

Description

This application claims the benefit of U.S. Provisional Patent Serial No. 60/624,045, filed Nov. 1, 2004, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

This invention relates generally to the field of tube bending apparatuses and the dies used therein, and more particularly to such apparatuses and dies that are used in bending thin-walled, small diameter metal tubes, and to the methodology used in accomplishing the bending of the tubes.
Apparatuses for bending metal tubes without crimping or deforming the circular cross-section of the tubes are well known. For the bending of thin-walled, small diameter metal tubes made of aluminum or similar metal, relatively small apparatuses have been developed and are often powered hydraulically. An example of such an apparatus is shown in my U.S. Pat. No. 5,237,847, issued on Aug. 24, 1993, the disclosure of which is hereby incorporated by reference. With this type of tube bending apparatus, a generally semi-circular bending shoe or die is advanced by a hydraulic cylinder between a pair of circular bending rollers or dies, with the tube to be bent disposed there between. In other types of tube bending apparatuses, one end of the tube is abutted against a stop member and the bending dies are pivoted in a curved path to accomplish the bending of the tube, or one bending die is pivoted about a fixed die.
A drawback to these known tube bending apparatuses is that a minimum length of unobstructed tube must be present in order to accomplish a chosen bend, since the dies must be free to traverse the tube. Furthermore, for short tubes where fittings, connectors, beads, flares or the like that extend outwardly from the tube are already connected or formed on each end of the tube, bends close to 180 degrees cannot be accomplished because the fittings, etc. preclude removal of the tube from the bending die located on the interior of the bend after the bend is imparted in the tube. Because of this, short tubes with fittings or the like are manufactured by first bending the short tube section, then attaching the fittings using braising, welding, mechanical interlocking or similar techniques. The final products so manufactured are more susceptible to failure because of the inherent weaknesses in the joining methods.
It is an object of this invention to provide an apparatus and method that enables the bending to and beyond 180 degrees of a short segment of thin-walled, small diameter tubing upon which fittings, connectors, beads, flares or the like that extend outwardly from the tube are already connected or formed on each end. It is an object to provide such an apparatus and method whereby a short tube segment can be machined or formed such that the tube and the fittings, connectors, beads, flares, etc. are an integral, one-piece member.

SUMMARY OF THE INVENTION

Manual or powered apparatuses using dies, also known as rollers or shoes, to receive or retain a portion of a tube and which impart a bend or curve in the tube are generally known in the art. The invention is a tube-bending split die and an apparatus and method for bending short segments of metal tubing utilizing such split die, suitable but not limited to the bending of thin-walled, small diameter, metal tubing, wherein the bending is accomplished by utilizing an interior bending die about which the tube is bent to form a permanent curve or bend in the tube. In a preferred embodiment, an exterior bending die is disposed in tandem with the interior bending die, such that the tube is disposed between the two dies and the entire cross-sectional circumference of the tube is completely enclosed within the combined generally semi-circular channels of the two dies. The dies are preferably annular and are preferably mounted on shafts that allow both dies to rotate during the bending operation, such that the tube-receiving channels are completely annular in the plane perpendicular to the rotational axis.
The interior bending die is a split die constructed such that it is separable into two halves along the bending plane, i.e., the plane perpendicular to the rotational axis disposed at the mid-point of the tube-receiving channel. In this manner, when a short tube is bent to such a degree that the fittings or other obstructions on the ends of the tube preclude withdrawal of the interior bending die from the tube in a linear manner, the interior split die can be separated in the axial direction to release the bent tube.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration showing a straight, one-piece tube and fitting combination disposed between an interior bending die and an exterior bending die incorporated as part of a representative tube bending apparatus.
FIG. 2 is a view taken along line II-II of FIG. 1 along the tube axis, with the tube shown in cross-section.
FIG. 3 shows the tube now having a bend of 180 degrees, such that the interior bending die is entrapped by the fittings.
FIG. 4 is a lateral view showing the interior bending die entrapped by the fittings.
FIG. 5 is a view similar to FIG. 4, showing the interior bending die separated into halves for release of the bent tube.

DETAILED DESCRIPTION OF THE INVENTION

With reference to the drawings the invention will now be described in detail with regard for the best mode and the preferred embodiments. In general, the invention comprises a split tube-bending die, and in particular a split interior tube-bending die, and the tube bending apparatus and method incorporating such a split interior tube-bending die.
As represented in the figures, the work piece to be bent is a relatively short, tubular member 10 that as shown comprises a short, thin-walled, tube segment 11 that is linear or only slightly curved in the pre-working state. Obstructive members shown generally as fittings or connectors 12 are disposed on each end of the tube segment, it being understood that the fittings 12, as the term is used and illustrated herein, is intended to represent and include any fittings, connectors, beads, flanges or similar obstructive devices that extend outwardly from the surface of the tube segment 11, i.e., any obstructive member that has a increased radius or any extensions that extend radially above the tube outer surface. The apparatus and methodology are capable of working a tubular member 10 wherein the fittings 12 are joined to the tube segment 12 by any known connecting techniques, such as braising, welding, bonding, mechanical interlocking or the like, or wherein the fittings 12 and tube segment 11 are formed or machined as a one-piece, integral tubular member 10.
Bending dies 20 and 30 are disposed in cooperating or mating manner such that the dies 20 and 30 encompass a portion of the tube segment 11 at the point where bending is to be imparted. The bending dies 20 and 30 are mounted to frames, blocks or the like that form part of a tube bending apparatus, which may be of any known type, manual or powered, suitable for bending tubular members. Use of an interior bending die 20 and an exterior bending die 30 in this configuration is well known within the field of tube bending apparatuses, such that as exterior bending die 30 is manipulated about the interior bending die 20 relative to the tubular member 10, one of the ends of the tubular member 10 remaining fixed, the tube segment 11 will be bent about interior bending die 20. As illustrated in FIGS. 1 and 3, a representative tube bending apparatus 100 is shown, the apparatus 100 comprising a base member 101, a locking arm 102 and a bending arm 103. The interior bending die 20 is mounted onto the base 101 on a shaft 21 such that rotation of the bending die 20 is allowed. The bending arm 103 is pivotally mounted to the base 101 on shaft 21, such that bending arm 102 pivots about the longitudinal axis of shaft 21 and bending die 20. The exterior bending die 30 is connected by shaft 31 to the end of locking arm 102, which pivots relative to the bending arm 103, such that with a tube 11 disposed in the interior bending die 20 the exterior bending die 30 can be pivoted into abutting relation with the interior bending die 20 to encircle the tube 11. To bend the tube 11, the bending arm 103 is rotated relative to the base member 101, such that the exterior bending die 30 rotates about the interior bending die 20, as seen in FIG. 3.
The bending dies 20 and 30 as shown are of essentially similar configuration, but it is contemplated that the dies could vary in configuration without exceeding the bounds of the invention. For example, one or both of dies 20 and 30 could be only partially annular, such that the channels 22 and/or 32 do not extend a full 360 degrees. Likewise, the dies 20 and 30 could be non-annular such that channels 22 and 32 are non-annular. Exterior bending die 30 as shown preferably comprises an annular member having a tube-receiving channel 32, substantially semi-circular in the direction perpendicular to the bending plane, bounded by a pair of flanges 33 mounted on a s shaft 31 such that the exterior bending die 30 will rotate about the longitudinal axis of shaft 31, the longitudinal axis being perpendicular to the bending plane.
Interior bending die 20 as shown is similar in configuration to exterior bending die 30, preferably comprising an annular member having a tube-receiving channel 22, substantially semi-circular in the direction perpendicular to the bending plane, bounded by a pair of flanges 23. Interior bending die 20 is a split die, separable in the direction perpendicular to the bending plane, i.e., a plane perpendicular to the longitudinal axis of shaft 21, into a first divided portion or half 24 comprising a portion of tube-receiving channel 22 and one flange 23 and a second divided portion or half 25 comprising the remaining portion of tube-receiving channel 22 and the other flange 23, such that interface surfaces 26 are created in the middle of the annular channel 22 between the flanges 23, as seen in FIG. 5. The divided portions 25 and 26 are mounted on shaft 21, such that the interior bending die 20 will rotate about the longitudinal axis of shaft 21, the longitudinal axis being perpendicular to the bending plane and parallel to the longitudinal axis of the exterior bending die 3. Alternatively, the shaft 21 may be divided, with the shaft portions sharing a common longitudinal axis. Preferably, split die securing means, such as an insert member 27, such as a pin, post, key or the like, constructed to mate with an insert cavity 27 of corresponding configuration, are provided to better secure and align the first and second divided portions 24 and 25 during the bending operation. As shown in the drawings, the divided portion 24 is separable from divided portion 25 in the axial direction, either such that the divided portion 24 is completely removable from shaft 21, is able to be moved axially along shaft 21 a sufficient distance to free tube 11 after bending, or, in the case of a divided shaft 21, the divided portion 24 and its shaft portion is separable.
To bend the tubular member 10, the tube segment 11 is disposed between the bending dies 20 and 30, as shown in FIG. 1, and the tube segment 11 is bent to the desired configuration, shown as a bend of 180 degrees about the interior die member 20 in FIG. 3, by pivoting the bending arm 103 relative to the base member 101 and interior bending die 20. As shown in FIGS. 3 and 4, even if exterior bending die 30 is removed, the fittings 12 prevent removal of the tubular member 10 from the interior bending die 20, since the flanges 23 cannot pass between the fittings 12 as they are now disposed adjacent to each other in the bent configuration. To release the bent tubular member 10, the first and second divided portions 24 and 25 of interior bending die 20 are separated in the axial direction, as shown in FIG. 5. This allows the bent tube member 10 to be released from the remaining divided portion 24 or 25 since the fittings 12 are no longer restricted by the combination of flanges 23.
It is understood that equivalents and substitutions for certain elements and components set forth above may be obvious to those skilled in the art, and thus the true scope and definition of the invention is to be as set forth in the following claims.

Claims

1. In a tube bending apparatus comprising an interior bending die about which a tube is bent within a bending plane, the improvement comprising said interior bending die being a split die, such that said interior bending die can be separated in the direction perpendicular to said bending plane to release said tube.

2. The apparatus of claim 1, wherein said interior bending die comprises divided portions, each said divided portion mounted onto a shaft.

3. The apparatus of claim 2, wherein said interior bending die further comprises a tube-receiving channel substantially semi-circular in the direction perpendicular to said bending plane.

4. The apparatus of claim 3, wherein said tube-receiving channel is annular.

5. The apparatus of claim 2, said tube bending apparatus further comprising an exterior bending die, wherein said interior bending die cooperates with said exterior bending die during the bending operation.

6. The apparatus of claim 3, said tube bending apparatus further comprising an exterior bending die comprising a tube-receiving channel substantially semi-circular in the direction perpendicular to said bending plane, wherein said interior bending die cooperates with said exterior bending die during the bending operation such that the combination of said exterior bending die tube-receiving channel and said interior bending die tube-receiving channel completely encircles said tube.

7. The apparatus of claim 2, further comprising means to secure and align said divided portions of said interior bending die to each other.

8. The apparatus of claim 7, wherein said securing and aligning means comprises an insert member disposed in one of said divided portions and an insert cavity disposed in the other of said divided portions, said insert member being received by said insert cavity when said divided portions are adjoining.

9. A tube bending apparatus comprising an interior bending die about which a tube is bent within a bending plane, said interior bending die comprising a tube-receiving channel, the improvement comprising said interior bending die being a split die, such that said interior bending die can be separated into divided portions in the direction perpendicular to said bending plane to release said tube.

10. The apparatus of claim 9, wherein each said divided portion is mounted onto a shaft.

11. The apparatus of claim 9, wherein said tube-receiving channel is substantially semi-circular in the direction perpendicular to said bending plane.

12. The apparatus of claim 9, wherein each said divided portion comprises a portion of said tube-receiving channel.

13. The apparatus of claim 9, wherein said tube-receiving channel is annular.

14. The apparatus of claim 9, said tube bending apparatus further comprising an exterior bending die, wherein said interior bending die cooperates with said exterior bending die during the bending operation.

15. The apparatus of claim 14, said tube bending apparatus further comprising an exterior bending die comprising a tube-receiving channel substantially semi-circular in the direction perpendicular to said bending plane, said interior bending die further comprising a tube-receiving channel substantially semi-circular in the direction perpendicular to said bending plane, wherein said interior bending die cooperates with said exterior bending die during the bending operation such that the combination of said exterior bending die tube-receiving channel and said interior bending die tube-receiving channel completely encircles said tube.

16. The apparatus of claim 9, further comprising means to secure and align said divided portions of said interior bending die to each other.

17. The apparatus of claim 16, wherein said securing and aligning means comprises an insert member disposed in one of said divided portions and an insert cavity disposed in the other of said divided portions, said insert member being received by said insert cavity when said divided portions are adjoining.

18. A tube-bending die comprising a tube-receiving channel and a pair of flanges, wherein said tube-bending die can be separated into two divided portions, each divided portion comprising one of said flanges and a portion of said tube-receiving channel, wherein said tube-bending die is mounted onto a shaft, and wherein at least one of said divided portions can be moved axially on said shaft to release a tube.

19. The apparatus of claim 18, wherein said tube-receiving channel is substantially semi-circular in the direction perpendicular to said bending plane.

20. The apparatus of claim 18, further comprising means to secure and align said divided portions of said tube-bending die to each other, said securing and aligning means comprising an insert member disposed in one of said divided portions and an insert cavity disposed in the other of said divided portions, said insert member being received by said insert cavity when said divided portions are adjoining.