WO2001041949A2

WO2001041949A2 - Blank shaping tool

Info

Publication number: WO2001041949A2
Application number: PCT/US2000/033322
Authority: WO
Inventors: Maurilio J. Udave
Original assignee: R.J. Tower Corporation
Priority date: 1999-12-10
Filing date: 2000-12-08
Publication date: 2001-06-14
Also published as: WO2001041949A3

Abstract

A system for shaping a blank (20) of stock material into a shaped product includes a base guide (12), a forming tool (16) and a mandrel (14). The blank (20) is placed between the mandrel and the forming tool and the mandrel is then moved toward the base guide. As the forming tool engages the base guide, the forming tool closes around the mandrel, causing the blank to bend and conform to the interior of the forming tool and the exterior of the mandrel. The shape of the base guide is chosen to correspond with the forming tool, while the shape of the forming tool and mandrel are chosen to correspond with the desired shape of the final product.

Description

BLANK SHAPING TOOL Background of the Invention Field of the Invention

The present invention relates generally to tools for shaping blanks. More specifically, the present invention provides a system of tools for forming stock material into a wide variety of open shapes. The open shapes may then be welded or joined, thus closing the shape to form a product having an enclosed constant or tapered cross-section. Description of the Related Art

It is quite common to form a unitary component from a blank of stock material such as sheet metal. The blank is bent or stamped into the desired configuration and the material will maintain the shape it was formed into, depending on its mechanical properties. The shaping of such stock material is often done by large, powerful presses. The blank is clamped or otherwise secured in such a press. A portion of the blank is aligned with a rigid, moving member which bends the blank to the desired angle. This is usually done by straight line presses, which as their name implies, form a single bend in a straight line.

Various stamping processes are known, which some allow a moderately curved product to be formed. The presses have a single direction of travel which limits the type of product that can be manufactured. Further, the press must be provided with an exit, thus requiring an open channel of some type.

It is known to use a die to force a blank of material through a pair of wiping steels. As this occurs, the sides of the blank are caused to bend, to a maximum of 90°. This allows U-shaped or similar products to be formed, however, no practical mechanism exists to bend beyond 90° with the single press stroke.

In order to form more complex shapes, small segments are typically bent one at a time. The blank must then be moved between each bend. This is a very tedious and time consuming process and can only produce a very limited number of different shapes. It is often desirable to form even more complex three-dimensional shapes, such as tubular structures having circular or non-circular cross sections, from the same type of stock material. Various processes do exist to accomplish this task. For example, raw material may be extruded into the desired shape. However, this is an expensive process and severely limits the choice of materials available for use. The difficulty with the previous methods for forming shaped objects is that none offer the ability to form a complete, complex object having an enclosed or substantially enclosed cross section with a single press stroke. It is an inherent drawback of using linearly driven presses, that a single press stroke can only bend a blank so far. No mechanism exists to conform the bending process to the whole shape of the die or mandrel being utilized. That is, a die can force a blank into a channel causing the blank tc partially match the channel, however, the channel cannot continue to conform the blank to the whole shape of the die. The channel cannot cause the blank to completely wrap around the whole of the die. Due to this limitation, there does not presently exist a tool which can form a blank into a complex shape having an enclosed or substantially enclosed cross section.

As such, there exists a need to provide a tool capable of quickly and easily forming a blank of raw material into a complex shape having an enclosed or substantially enclosed cross section.

Summary of the Invention The present invention includes a base guide and a mandrel which are shaped to mate with one another. The base guide and mandrel are specifically designed so they can be moved with a great degree of force towards one another. A forming tool is also provided that has an interior similar in shape to the desired shape of the completed product. For example, when forming tubes from blanks, the forming tool is configured to specifically accommodate the formation of a tubular structure. The shape of the base guide is also chosen to have an interior similar in shape so that an interaction between the two causes the forming tool to close as it is accepted into the base guide.

In use, the forming tool is aligned with the base guide while a blank of stock material is positioned between the mandrel and the forming tool. The mandrel is then driven towards the base guide. As the forming tool is forced to engage an opening in the solid base guide, the forming tool is caused to close in on itself. This movement is aided by a medially disposed hinge on the forming tool. The forming tool then engages the blank and causes it to bend around the mandrel. As such, the shape of the mandrel is chosen to correspond to the interior of the completed component. As the mandrel continues to be driven, the forming tool is forced farther into the base guide thus causing the forming tool to close tightly around the mandrel. As a result, the blank is bent into the shape of the mandrel and forming tool. The forming tool is particularly advantageous because it can surround the mandrel.

For example, to form a part having a circular cross-section, a base guide that has a semi- cylindrical or prismatic channel is selected. Simply forcing the blank into this channel will cause the blank to be bent into a "U" shape. The forming tool has the ability to close behind or around the mandrel. The closing motion of the forming tool allows an enclosed shape to be formed with a single press stroke.

Generally, opposite ends of the blank will be moved into close proximity with one another, however, a gap will usually remain between them. The bending process does not couple the two ends together, although as a variation, they could be caused to overlap. An appropriate fastening process may then be completed.

After the blank has been bent into the appropriate shape, it is removed and may be inserted into a welding cell. The welding cell is shaped to correspond to the bent blank. The bent blank can be moved along the welding cell by the rotation of shaped welding fixtures. The welding fixtures serve to clamp the blank so that the proper gap is achieved. This gap is then welded via an appropriate welding method. At this point, the blank has been formed into a shaped, unitary component.

The tool system of the present invention can be configured to quickly, easily and accurately form a wide variety of shaped products from virtually any type of malleable stock material.

It is an object of the present invention to provide a system of tools to quickly and easily form a blank of stock material into a shaped component.

It is a further object of the present invention to provide a shaped mandrel which cooperates with a forming tool and base guide so as to shape a material in a single press stroke.

It is yet another object of the present invention to provide a forming tool that is moveable from an open position to a closed position, wherein the closed position partially or totally encases the mandrel.

Brief Description of the Drawings Figure 1 is a schematic, side sectional view of a blank shaping tool with a blank in position to be formed.

Figure 2 is a schematic, side sectional view of a blank shaping tool illustrating a blank after it has been substantially shaped.

Figure 3 is a schematic, side sectional view of a welding cell containing a bent blank. Figure 4 is a top planar, view of a welding cell containing a bent blank.

Detailed Description of the Preferred Embodiment Referring to Figure 1, the blank shaping tool of the present invention is illustrated in cross section and generally referred to as 10. Blank shaping tool 10 as shown in this embodiment is configured to form a tube from a blank 20 of malleable material. It is to be understood that virtually any shape could be formed, as explained below, however the components must be reconfigured to form these structures. Base guide 12 is formed from a material which is suitably strong in relation to the chosen stock material. Base guide 12 includes a channel area 15. To manipulate blank 20 into a tubular shape, the lower portion of the channel area 15 is chosen to have a semi-cylindrical or prismatic configuration that arcuately tapers to the corners. The length of the components and the stock material will be chosen to provide an end product having the desired length.

Mandrel 14 has a structure having a constant or tapered cross-section with any geometrical shape that has dimensions that are similar to the semi-cylindrical or prismatic portion of channel area 15. Mandrel 14 is formed from a suitably strong material. In general, the blank 20 is forced into channel area 15 by mandrel 14 moving downwards (as illustrated). A suitable fixture is provided to support mandrel 14 and allow its vertical movement. Likewise, an appropriate press is provided to drive mandrel 14, such as a hydraulic, mechanical or pneumatic actuator. However, this action in and of itself would only form the blank into the shape of a U, rather than the desired tubular configuration. Therefore a forming tool 16 is disposed between base guide 12 and blank 20. Forming tool 16 is a rigid member having a hinge 18 that allows forming tool 16 to move from an open position (Fig. 1) to a closed position (Fig. 2). In the open position, forming tool 16 has two side-by-side semi- cylindrical or prismatic areas. In the closed position, forming tool 16 as illustrated has a nearly internal cross-section. When closed, forming tool 16 partially encases mandrel 14.

As downward pressure is applied by mandrel 14, blank 20 is forced against forming tool 16. Forming tool 16 is consequently forced against base guide 12. As mandrel 14 continues its downward (as illustrated) movement, the arcuate portions of base guide 12 cause the forming tool to begin to close. This movement then bends blank 20 around mandrel 14. Alternatively, mandrel 14 could be a static fixture and base guide 12 (or a variation thereof) could be the moving, driven element. Essentially, a downward force is translated, through the closing of the forming tool into an inwardly directed force. This translation of force causes the blank to wrap around mandrel 14. The final selected shape of mandrel 14 can vary. For example, by selecting mandrel

14 to be longer than the desired coupled product, the extreme ends of mandrel 14 can be driven, leaving the area between them unobstructed. In other words forming tool 16 could completely surround a section of mandrel 14, and even overlap itself, if desired. In some cases, this may not be necessary. If the final shape requires or permits a gap, that gap can accommodate a similarly shaped portion extending upwardly (as illustrated) from mandrel 14. This portion could then be used to control and drive mandrel 14. Essentially, this simply means that only the lower portion of mandrel 14 needs to correspond to the final desired product shape, so long as a sufficient channel or curvature is provided on the upper portion to accommodate forming tool 16. This allows for more flexibility in designing the various components to produce a particularly shaped product.

Figure 2 illustrates how the closed forming tool 16 has bent blank 20 into a circular cross sectional shape, rather than a U shaped cross section. This occurs because the outer prongs 17 of forming tool 16 are able to close "behind" mandrel 14, whereas a stationary block, such as base guide 12 cannot. As shown, forming tool 16 does not close completely around mandrel 14 and blank 20, thus a gap 22 is formed between opposite ends of blank 20. Alternatively, forming tool 16 could be configured so that no gap 22 existed or so that an overlap is created. As discussed, blank 20 can be formed into any closed or open shape desired, including shapes having circular, oval, rectangular or virtually any other constant or tapered cross section. Base guide 12, forming tool 16 and mandrel 14 are simply selected to form the appropriate interior and exterior configuration for blank 20. It should be noted that the shape of mandrel 14 really dictates the final shape of the blank. That is, the circular or tubular forming tool 16 illustrated will close appropriately around almost any shape of mandrel 14. For example, assuming mandrel 14 had a square cross section, the closing action of a circular forming tool 16 would still shape the blank 20 into a tube having a square cross section. However, forming tool 16 can have a shape similar to the desired final shape in order to uniformly compress the entire (or a substantial portion) outer perimeter of blank 20. Once blank shaping tool 10 has bent blank 20 into the appropriate shape, blank 20 is removed. In some instances, this will complete the processing of blank 20, as it is now in a useable configuration. Often, it may be desirable to bond the edges 23 of the blank 20 that have been brought together during the shaping process. In other words, gap 22 is welded or otherwise closed. Figure 3 illustrates a welding cell 24. The bent blank 20 is placed between a pair

(more or less as needed) of rotating welding fixtures 26. Welding fixtures 26 closely approximate the shape of the formed blank 20. Rotation of the welding fixtures 26 causes blank 20 to move longitudinally between them. The welding fixtures 26 are positioned to clamp blank 20 and close gap 22, as desired.

An appropriate welding tool 28 is positioned near gap 22 in blank 20. As the bent blank 20 is moved longitudinally between welding fixtures 26, welding tool 28 welds the opposite ends 23 of blank 20, forming a closed component. Alternatively, the part could be held stationary as the welding head is moved along the seam. Any type of appropriate welding process 28 may be chosen, including : MIG, TIG, LASER, EBW, MASH, Friction Stir Welding, or any other desired type of welding suitable for the material used in the blank 20. Alternatively, other types of joining processes can be utilized such as riveting, screwing, bolting or the like, as appropriate for the material chosen.

The present invention is advantageous in that a piece of stock material can be formed into a complex shape having an enclosed or partially enclosed cross section, in a single press stroke. The unique configuration of the present components allow forming tool 16 to surround or close behind the driving mandrel 14. Essentially, this combination allows for a utilization of simple linear motion in a two dimensional plane. Thus, with one linear press stroke, a component having an enclosed or partially enclosed cross section may be formed around a shaped mandrel 14.

Those skilled in the art will further appreciate that the present invention may be embodied in other specific forms without departing from the spirit or central attributes thereof. In that the foregoing description of the present invention discloses only exemplary embodiments thereof, it is to be understood that other variations are contemplated as being within the scope of the present invention. Accordingly, the present invention is not limited in the particular embodiments which have been described in detail therein. Rather, reference should be made to the appended claims as indicative of the scope and content of the present invention.

Claims

I claim: 1. A blank shaping tool for fabricating parts having a substantially enclosed cross- section comprising: a base guide having a shaped channel area; a moveable fomiing tool having an outer shape that is cooperative with the shaped channel area; and a mandrel having a shape similar to a desired final shape, wherein a blank positioned between the mandrel and the forming tool will be formed into a product having a shape similar to the mandrel after the mandrel is caused to force the blank and the forming tool into the channel area of the base guide, consequently causing the forming tool to partially surround the mandrel.

2. The blank shaping tool of claim 1 wherein the formmg tool is hinged.

3. The blank shaping tool of claim 1, further comprising: a welding station including at least one welding fixture having a shape similar to a bent blank, which guides and moves the shaped blank through the welding station; and a welder positioned near the welding fixture to weld the blank into a unitary component.

4. The blank shaping tool of claim 1 , further comprising: a welding station including at least one welding fixture having a shape similar to a bent blank, which moves along the shaped blank as the shaped blank is held stationery in the welding station; and a welder positioned near the welding fixture to weld the blank into a unitary component.

5. A method of shaping a blank of stock material, comprising: placing a blank between a mandrel and a forming tool wherein the forming tool is positioned adjacent a base guide; and forcing the mandrel to press the blank against the forming tool, which in turn moves the forming tool into engagement with the base guide, causing the fomiing tool to close around the mandrel, bending the blank.

6. The method of claim 5, further comprising: clamping the shaped blank within a welding station; and welding the shaped blank to form a unitary member.

7. A blank shaping tool comprising: a base guide having a shaped channel area; a moveable forming tool having an outer shape that is cooperative with the shaped channel area, wherein movement of the forming tool into the shaped channel area causes the forming tool to move to a closed position; and a mandrel wherein at least a portion of the mandrel has a shape similar to a desired final shape, wherein a blank positioned between the mandrel and the forming tool will be formed into a product having a shape similar to the portion of the mandrel after the blank is forced against the portion of the mandrel at least in part by the forming tool moving into the channel area of the base guide, consequently causing the forming tool to substantially surround the mandrel.

8. The blank shaping tool of claim 7 wherein the forming tool is hinged.

9. The blank shaping tool of claim 7, further comprising: a welding station including; at least one welding fixture having a shape similar to a bent blank, which guides and moves the shaped blank through the welding station; and a welder positioned near the welding fixture to weld the blank into a unitary component.

10. The blank shaping tool of claim 7, further comprising: a welding station including; a moveable welder; and at least one welding fixture having a shape similar to a bent blank, which holds the shaped blank while the welder moves along and welds the seam.