WO2007077582A1

WO2007077582A1 - Method for making soft bends in sheet metal

Info

Publication number: WO2007077582A1
Application number: PCT/IS2006/000001
Authority: WO
Inventors: Kristjan Arnason
Original assignee: Verkfraedistofa Kristjans Arnasonar
Priority date: 2006-01-05
Filing date: 2006-01-05
Publication date: 2007-07-12

Abstract

A method to bend sheet material (1), where bars (2) are clamped to the edges of the sheet material (1) , or at equal distance from the bend line (5) and a loop is formed by straps (3). The loop pf sheet material (1) is then clamped together with beams (6) aligned with markings (4), which positions on the sheet material (1) depend on the bend radius (R) and the material thickness. There is also disclosed a method to bend a sheet material (1), where beams (6) are spaced a certain distance apart and a round bar is used to draw the sheet material (1) into a U-shape between the beams (6). Then the side of the beams are aligned with the markings (4) and the beams (6) are clamped around the sheet material (1) to form the bend.

Description

Method for making soft bends in sheet metal.

Background of the invention.

In the past soft bends or large radius bends have been made with form blocks or bending brakes around large radius bar. In these cases a special form block or a radius bar has to be made for each size of radius. Male form blocks have been used in connection with rubber blocks or a bag with fluid under pressure. In patent

EP 0 834 389 A2 a strap is wound around a sheet metal and tension on the strap used to form soft radius bend.

Brief description of the drawings. Figure 1 shows cross section of a sheet with bars clamped to the edges and straps in place.

Figure 2 shows cross section of the sheet with a loop formed.

Figure 3 shows where the loop has been clamped between rectangular bars.

Figure 4 shows the clamped sheet with strap and bars removed. Figure 5 shows the sheet clamped between bars when the sheet faces touches.

Figure 6 shows the sheet formed when removed from the clamps.

Figure 7 shows a typical section of a wing leading edge.

Figure 8 shows a typical graph showing bend radius for different material thicknesses and distances between clamping points. Figure 9 shows how the clamping bars can be placed on shaw horses for the simplest application of the bending method.

Figure 10 shows how the clamping bars can be made for added strength and reduced deflection.

Figure 11 shows how bars can be arranged where relatively long sheet are to be formed.

Figure 12 shows how a space block can be arranged to form different bend radiuses and different bend angles.

Detailed description of preferred embodiments. Figure 1. shows section through a sheet metal to be bent. A wood bars (2) slightly longer then the sheet metal are clamped to the sheet metal edges, with C-clamps, or equal distance from intended centerline of bend (5). Straps (3) are placed at each end of the sheet of metal and thightened around the wooden bar (2) ends until a loop of the sheet metal is formed as shown in figure 2. The loop of sheet metal is placed between two rectangular tubes or bars (6) with round corners and the loop is clamped between these bars as shown in figure 3. Now the wooden bars (2) can be removed and the sheet moved such that the markings (4) on the sheet metal are aligned with the upper surface of the rectangular bars (6). The rectangular bars are then clamped around the sheets until the faces of the sheet touches as shown in figure 6. When the clamps are removed the sheet metals looks like what is shown in figure 6. The radius formed will depend on the distance between markings on sheet metal. A graph shown in figure 8. would be made before by experimental data obtained by bending strips of sheet metal of different thicknesses and with different distances between markings. It may be necessary to make two curves for each thickness of sheet. One for bending along grain and another for bending across the grain of sheet metal. A sheet of metal can easily be adopted to leading edge of a wing as shown in figure 7. for riveting or glueing. By this method it is quite easy to bend skin for leading edge of a tapered wing by simply having the distance between the clamping points different at each end of the sheet. For long sheets bending it may be necessary to strengthen the rectangular bars (6) as shown in figure 10 or use vertical beams (7) outside the sheet metal loop and clamping together above and below sheet metal loop.

Individual bending can be done even though experimental data is not obtained beforehand. The marking is done with a distance long enough to be on the safe side. After the first test bend a measurement is made of the bend radius. If the radius is too large an new marking is done with slightly less spacing and the sheet is clamped again. This process is then repeated until the correct radius is obtained. To obtain different bend angles a space block (8) of different thickness can be between the sheet metal at clamping point as shown in figure 12. It will be necessary to obtain experimental data for different material thicknesses and different thickness of space block.

The invention being thus described, it will be obvious that the same may be varied in many ways. The bending can be done by hand, by simple machinery og by automated machinery for different materials and different bending angle. Such variations are not to be regarded as departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art as intended to be included within the scope of the following claims.

Claims

Claims.

1. Claim is made for a method to bend sheet material, where bars (2) are clamped to the edges of the sheet, or equal distance from the bend line and a loop is formed with straps (3). The loop of sheet is then clamped together with beams (6) and with the markings (4), which depend on bend radius and material thickness, at the side of beams (6).

2. Claim is made for a method to bend a sheet material, where beams (6) are spaced a certain distance apart and a round bar is used to draw the sheet material into a U-shape between the beams (6). Then the markings (4) are aligned to the side of beams (6), which are then clamped around the sheet material to form the bend.

3. Claim is made for bending skin for leading edge of aircraft wings as defined in claims 1 and 2, whether straight or tapered.

4. Claim is made for bending skin for leading edges of wind turbine blades as defined in claims 1 and 2. whether straight or tapered.

5. Claim is made for the method to form smooth bends in sheet material or bars of any cross section done manually, by machinery or any automated machinery as defined in claims 1 and 2.

6. Claim is made for forming smooth bends in sheet of different bend radius and different bend angles using space block (8) as characterized by claims 1 and 2.

7. Claim is made for the method of forming smooth bends in bars of any cross section characterized by claims 1 and 2.