Center shifted roll forming

Abstract

A roll forming machine capable of forming the corrugated metal web of a sinusoidal structural member is provided. The preferred embodiment includes a material feeding means, a material guiding means, and at least two forming cylinders. The material feeding means receives a sheet of material, and is in material communication with the material guiding means. The material guiding means receives the sheet of material, guiding the sheet of material into the forming cylinders and preventing significant movement or buckling of the sheet of material. The forming cylinders are a set of at least two substantially aligned and parallel cylinders, having a separation between sufficient to receive the sheet of material. The forming cylinders can alternately orbit one around the other, one forming cylinder axis being held substantially stationary while the other forming cylinder orbits the stationary cylinder, bending the sheet of material and forming the desired web geometry.

Description

BACKGROUND

1. Field of Invention

This invention relates generally to an improved roll forming mechanism. And, more particularly, this invention relates to an improved roll forming mechanism for the manufacture of the corrugated webbing of structural members for the aerospace industry.

2. Description of Prior Art

In the aircraft industry, it is common to utilize I-beam like structural members having a sinusoidal web extending normally between a top and bottom flange. The generally sinusoidal shape of the web provides increased strength to weight performance, improved stiffness, and decreased volume. In order to accommodate the aircraft wiring harness, hydraulic and fuel lines, as well as immediate strength and volume requirements, the geometry of the web may vary from sinusoidal to planar, creating a potentially non-repeating web corrugation pattern.

Currently, structural members are generally constructed from metal or composite materials. With either choice of material, the construction of a structural member with a sinusoidal web is a challenge, in maintaining quality, tolerances, and minimizing costs. With the high cost of manufacturing composite structural members, due to the labor intensive techniques utilized, it is at times more economical and practical to use metals, such as titanium and aluminum, to construct sinusoidal structural members, when the design allows for it.

To construct the sinusoidal web, it is common to use a roll former or other similar device to create the desired corrugated pattern. Certain materials, such as titanium alloy 6-4, have considerable spring-back properties, making them relatively difficult to roll form to the tight tolerances required in the aerospace industry. It was found that the titanium alloy, when bent to a known angle in a bending jig with a 0.75 inch mandrel, would return to an angle that was approximately 50% of the angle induced in the bending jig. For example, if the angle induced in the bending jig is 240 degrees, when removed from the bending jig the titanium alloy will return to an angle approximately equal to 120 degrees.

One method presently being used to form corrugated webbing is an intermeshing gear type former. The titanium alloy sheet is fed between two intermeshing gears to form the corrugated pattern. This method lends itself to very rapid production however it is not adjustable to accommotade for slight variations in metal spring back nor is it capable of producing variations in shape.

What is needed is a mechanism that can quickly and economically produce corrugated titanium webbing for a structural member. What is also needed is a mechanism that can induce a bending angle ranging approximately between 0 and 240 degrees, in any desired combination of alternating planar and curvilinear cross-sectional patterns.

SUMMARY OF THE INVENTION

In accordance of the present invention, a roll forming machine capable of forming the corrugated metal web of a sinusoidal structural member is provided. The preferred embodiment includes a material feeding means, a material guiding means, and at least two forming cylinders. The material feeding means receives a sheet of material, and is in material communication with the material guiding means. The material guiding means receives the sheet of material, guiding the sheet of material into the forming cylinders and preventing significant movement or buckling of the sheet of material. The forming cylinders are an assembly of at least two substantially aligned and parallel cylinders, having a separation between sufficient to receive the sheet of material. The forming cylinders can alternately orbit one around the other, one forming cylinder axis being held substantially stationary while the other forming cylinder orbits the stationary cylinder, bending the sheet of material and forming the desired web geometry.

The sheet of material is first fed into the forming rollers assembly when the assembly is in the home position, when the separation between the forming cylinders is aligned and able to receive the sheet of material from the guiding means. The sheet of material is advanced into the forming roller assembly, the length of the advancement being equivalent to the length of material needed to complete the desired arc. The first forming cylinder remains stationary in the home position, while the opposing second forming cylinder orbits around the first forming cylinder. The sheet of material is wrapped around the first forming cylinder as the orbiting second forming cylinder completes its partial orbit.

After the arc has been formed in the sheet of material, the orbiting forming cylinder returns to the home position, next to the stationary forming roller. In this home position, the sheet of material can once again be advanced a discrete distance sufficient to form the successive arc. In a opposite fashion, the second forming cylinder remains stationary in the home position, while the opposing first forming cylinder orbits around the stationary forming cylinder, both actions resulting in the formation of a sine like geometry.

During the forming of the metal web, the sinusoidal pattern of the web can be altered, creating various curves or planar sections. To produce a planar section, the sheet of material is advance while the forming cylinders are both in the home position. The length of the advancement corresponds to the designed planar section length. Additionally, various curves can be produced by reducing or increasing the angle of travel of the orbiting forming cylinder, effectively changing the sector of the arc.

If varying amplitudes of arcs in a sinusoidal webbing are desired, the forming cylinders can be removed and replaced with forming cylinders of the required diameter. Additionally, the separation between the forming cylinders can be adjusted to match the needed gap distance.

In an alternate embodiment, the present invention includes a material feeding means and at least two forming cylinders. The material feeding means receives a sheet of material, and is in material communication with the forming cylinder. The material feeding means can both feed and guide the material to the separation between the forming cylinders.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of an alternate embodiment of the present invention. is a top plan view of the preferred embodiment of the present invention.

FIG. 2 is a top plan view of the preferred embodiment of the present invention.

FIG. 3A-G are top plan views of the roll forming mechanism progressing through the forming process.

FIG. 4A-B are top plan views of the roll forming mechanism progressing through a planar section of the forming process.

FIG. 5A-C are perspective views of some potential webbing configurations manufactured by the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The detailed description set forth below in connection with the appended drawings is intended as a description of presently-preferred embodiments of the invention and is not intended to represent the only forms in which the present invention may be constructed and/or utilized. The description sets forth the functions and the sequence of steps for constructing and operating the invention in connection with the illustrated embodiments. However, it is to be understood that the same or equivalent functions and sequences may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the invention.

An alternate embodiment of the present invention can be seen in FIG. 1. The sheet of material (18) is received by the feeding means (12) through the material inlet (24). The material inlet is aligned with the clearance (28) between the first forming cylinder (14) and the second forming cylinder (16). The aligned components allow the sheet of material (18) to be fed through the system from the material inlet (24) to the forming cylinder assembly (32), where the sheet of material (18) can be formed. The feeding means (12) and the forming cylinder assembly (32) are fastened to a base (26).

The preferred embodiment of the present invention can be seen in FIG. 2. The sheet of material (18) is received by the feeding means (12) through the material inlet (24). The material inlet is aligned with the guiding gap (22) of the guiding means (20). The guiding gap (22) is aligned with the clearance (28) between the first forming cylinder (14) and the second forming cylinder (16). The aligned components allow the sheet of material (18) to be fed through the system from the material inlet (24) to the forming cylinder assembly (32), where the sheet of material (18) can be formed. The feeding means (12), guiding means (20), and the forming cylinder assembly (32) are fastened to a base (26).

As can be seen in FIG. 3A, a sheet of material (18), such as titanium alloy, is fed into the material inlet (24) of the feeding means (12). Upon exiting the feeding means (12), the sheet of material (18) is fed into the guiding gap (22) of the guiding means (20). And upon exiting the guiding means (20), the sheet of material (18) is fed into the clearance (28) between first forming roller (14) and second forming roller (16), while both are in the home position. The length of sheet of material (18) required to form one bend is advanced beyond first forming roller (14) and second forming roller (16). In FIG. 3B, the second forming roller (16) is held stationary, while first forming roller (14) orbits around the circumference of second forming roller (16), forming the designed curve in the sheet of material (18).

As can be seen in FIG. 3C, the second curve in the corrugation pattern is being formed. The length of sheet of material (18) required to form the second bend is advanced beyond first forming roller (14) and second forming roller (16). The first forming roller (14) is held stationary, while second forming roller (16) orbits around the circumference of first forming roller (14), forming the second designed curve in the sheet of material (18).

The continuation of this alternating orbit pattern can be seen clearly in FIGS. 3D-3G, demonstrating the formation of the successive curves in the corrugation pattern. The previously corrugated section of the sheet of material (18) is allowed to swing back and forth in the manner of a pendulum, while the corrugation bending is in process.

At times, designs may require a mixture of sinusoidal and planar sections in resulting web. In FIG. 4A, the forming of a planar section following a corrugation pattern can be seen. When in the home position, the sheet of material (18) is advanced the length required to create the planar section. After the sheet of material (18) has been advanced, a second series of corrugation can be formed, as seen in FIG. 4B. This alternation between linear and curvilinear geometries can be repeated as required.

This process of sheet of material (18) advancement and bending is repeated, with variations in feed rate and feed advancement distance to achieve the desired corrugation and planar geometry. While the sheet of material (18) is formed, the previously formed corrugations can be inspected for variation from the intended design; then, the feed rate and feed advancement distance can be adjusted to bring the overall corrugated web into design compliance.

A few of the many possible patterns of webbing for structural members can be seen in FIGS. 5A-C, to more clearly demonstrate the capabilities of the present invention. FIG. 5A demonstrates a planar section (30) at each end of the web, with a sinusoidal pattern in between. As can be seen in FIG. 5B, the planar section (30) is in the middle and each end of the web, with a corrugation pattern between. And in FIG. 5C, a less complex corrugation pattern is demonstrated. Although the above figures demonstrated by example some of the possible variations of patterns made possible by the present invention, there are numerous possible configurations not shown.

The present invention allows for the economical and rapid manufacture of metal webbing for corrugated structural members commonly used in the aerospace industry. Additionally, the present invention allows for the forming of a precise bending angle of 120 degrees in metals such as titanium alloy 6-4. Any angle between 0 and 120 degrees can be formed with the present invention. And additionally, the formation of a combination of linear and curvilinear geometries for webbing is made possible by the present invention. The present invention allows for a wide variety of patterns and separate webbing designs to be manufactured using a substantially similar setup, reducing manufacturing time and setup costs.

While the present invention has been described with regards to particular embodiments, it is recognized that additional variations of the present invention may be devised without departing from the inventive concept.

Claims

1. A roll forming machine adapted to facilitate the formation of either a sinusoidal corrugation or a combination of planar and sinusoidal corrugation from a sheet of material comprising: a material feeding means, having a material receiving means and a material exit; and a material guiding means, having a first face and a second face, said first face being opposite of said second face, a gap being formed through said material guiding means from said first face to said second face, said gap being of sufficient size to accommodate said sheet of material; and a first forming cylinder with a first central rotation axis and a first outer circumference; and a second forming cylinder with a second central rotation axis and a second outer circumference, said second central rotation axis being substantially parallel and coplanar to said first central rotation axis, said first forming cylinder having a separation from said second forming cylinder, said separation being of sufficient size to accommodate said sheet of material; wherein said sheet of material is received into said material receiving means, said material exit of said material feeding means being in material communication with said first face of said material guiding means and said material exit being substantially aligned with said gap of said material guiding means, said second face of said material guiding means being substantially aligned and in material communication with said separation between said first forming cylinder and said second forming cylinder when in an initial position; and wherein said first forming cylinder and said second forming cylinder form a alternating orbital roll forming station, said first and second central rotation axes alternately orbit one around the other following said outer circumferences forming a sinusoidal pattern in said sheet of material.

2. The roll forming machine of claim 1 wherein said material feeding means is a plurality of opposing parallel cylinders.

3. The material feeding means of claim 2 wherein said opposing parallel cylinders having a gap between to allow simultaneous tangential contact with said sheet of material.

4. The roll forming machine of claim 1 wherein said material feeding means feeds said sheet of material in discrete incremental lengths corresponding to the length needed to form a first arc in said sinusoidal pattern.

5. The roll forming machine of claim 1 wherein said first forming cylinder and said second forming cylinder in said initial position, forming a planar length of said sheet of material.

6. The roll forming machine of claim 1 wherein said first forming cylinder and said second forming cylinder have a diameter corresponding to said sinusoidal corrugation wavelength.

7. The roll forming machine of claim 1 wherein said first forming cylinder and said second forming cylinder are interchangeable with a third and fourth forming cylinder having a different diameter.

8. The roll forming machine of claim 1 wherein said first forming cylinder orbits around said second circumference of stationary said second forming cylinder, forming an orbital path angle sufficient to form a required arc.

9. The roll forming machine of claim 1 wherein said second forming cylinder orbits around said first circumference of stationary said first forming cylinder, forming an orbital path angle sufficient to form a required arc.

10. The roll forming machine of claim 1 wherein said material guiding means is in sufficient proximity of said first forming cylinder and said second forming cylinder to insure proper formation of a required arc.

11. The roll forming machine of claim 1 wherein said material guiding means has sufficient clearance to allow said roll forming cylinders to complete alternating orbits.

12. A roll forming machine adapted to facilitate the formation of either a sinusoidal corrugation or a combination of planar and sinusoidal corrugation from a sheet of material comprising: a material feeding means, having a material receiving means and a material exit; and a first forming cylinder with a first central rotation axis and a first outer circumference; and a second forming cylinder with a second central rotation axis and a second outer circumference, said second central rotation axis being substantially parallel and coplanar to said first central rotation axis, said first forming cylinder having a separation from said second forming cylinder, said separation being of sufficient size to accommodate said sheet of material; wherein said sheet of material is received into said material receiving means, said material exit of said material feeding means being in material communication with said separation between said first forming cylinder and said second forming cylinder when in an initial position; and wherein said first forming cylinder and said second forming cylinder form a alternating orbital roll forming station, said first and second central rotation axes alternately orbit one around the other following said outer circumferences forming a sinusoidal pattern in said sheet of material.