Method Of Shaping Ductile Sheet Material And Apparatus Therefor

Abstract

A method of and apparatus for shaping ductile sheet material to three-dimensional shapes having curved surfaces. The sheet material is bent to have a curved surface and is thereafter bent to have a further curved surface intersecting the first curved surface such that the bend takes place along a bend zone in in which the curved surfaces meet. The apparatus comprises a former shaped to have at least two curved surfaces intersecting in a former bend zone. Clamping means is provided and is adapted to clamp a length of ductile sheet material in curved shape against a first one of said curved surfaces of the former such that a a predetermined portion of the sheet material projects beyond the former bend zone. The former is displaceable towards an anvil having a curved shape complementary to the second curved surface of the former. The former and anvil are capable of shaping the sheet material between them upon displacement of the former and anvil towards each other, thereby causing the sheet material to bend around the former bend zone.

Description

This invention relates to a method of shaping ductile sheet material and apparatus therefor.

According to the invention there is provided a method of shaping ductile sheet material to three-dimensional shapes having curved surfaces, which includes the steps of bending such sheet material to have a curved surface and of thereafter bending the material to have a further curved surface intersecting the first curved surface such that the bend takes place along a bend zone in which the curved surfaces meet, the radii of curvature of the surfaces being equal to each other in the bend zone.

According to the method, the bending of the sheet material may take place about a former shaped to have at least two curved surfaces intersecting in a former bend zone, the sheet material may be clamped in curved shape against a first one of the curved surfaces of the former such that a predetermined portion of sheet material projects beyond the former bend zone. The former may be displaced towards an anvil having a curved shape complementary to the second curved surface of the former, the sheet material being thereby shaped between the anvil and the second curved surface of the former to have a shape corresponding to the two intersecting curved surfaces of the former.

The former and the anvil may be pivotally connected.

Furthermore, the bend zone in the sheet material may be initiated on the portion projecting beyond the former bend zone and may be progressively displaced along the said portion to the former bend zone by progressively displacing the former towards the anvil.

The radius of curvature of at least one of the curved surfaces of the sheet material may vary progressively in magnitude away from or along the bend zone. The sheet material may also have at least one further bend zone spaced from the first and defining the intersection of a third curved surface with the first curved surface.

At least one of the curved surfaces may furthermore have a zone of inflection.

The invention furthermore extends to an article of ductile sheet material whenever produced by the method as described above.

Still further according to the invention there is provided an apparatus for shaping ductile sheet material to three dimensional shapes having intersecting curved surfaces and comprising a former shaped to have at least two curved surfaces intersecting in a former bend zone; clamping means adapted to clamp a length of ductile sheet material in curved shape against a first one of the said curved surfaces such that a predetermined portion of the sheet material projects beyond the former bend zone; and an anvil having a curved shape complementary to the second curved surface of the former; the former and anvil being capable of shaping the sheet material between them upon displacement of the former and anvil towards each other, thereby causing the sheet material to bend around the former bend zone.

The former may be pivotally mounted relatively to the anvil. The apparatus may furthermore include displacing means for displacing the former and anvil towards each other. The former bend zone may furthermore have a zone of inflection.

The invention also extends to an article of ductile sheet material whenever produced with the apparatus as described above.

The invention is now described by way of example with reference to the accompanying drawings in which:

FIG. 1 shows a partly exploded three-dimensional view of an apparatus for shaping ductile sheet material to three-dimensional shapes, having intersecting curved surfaces;

FIG. 2 shows a three-dimensional view of an article in three-dimensionally shaped ductile sheet material having curved surfaces;

FIG. 3 shows a three-dimensional view of another article in three-dimensionally shaped ductile sheet material having curved surfaces;

FIG. 4 shows a three-dimensional view of yet another article in three-dimensionally shaped ductile sheet material having curved surfaces; and

FIGS. 5 to 7 show a three-dimensional view of still another article in three-dimensionally shaped ductile sheet material showing progreesive displacement of an initial bend zone towards a former bend zone.

Referring to FIG. 1, apparatus for shaping ductile sheet material to three-dimensional shapes having intersecting curved surfaces is generally indicated by reference numeral 10.

The apparatus shown in FIG. 1 is a demonstration model to demonstrate the steps involved in shaping ductile sheet material to three dimensional shapes having intersecting curved surfaces.

The apparatus 10 comprises a former 12 and an anvil 14. The anvil 14 is mounted on a frame 16, and the former 12 is removably mounted on displacing means in the form of a former holder 18 by clamping means in the form of nuts and studs 20 and 22 respectively. The former holder 18 is in turn pivotally mounted on frame 16 about a pivot axis 24 to permit pivotal displacement of the former holder 18 about the pivot axis 24 in the directions of arrows 26. The frame 16 is mounted on a base 17.

The former holder 18 is provided with a seat in the form of a curved clamping surface 28, and the lower surface 30 of the former 12 is correspondingly curved to present a first curved surface of the former 12. Two further curved surfaces 32 and 32.1 are provided on the former to intersect the first curved surface 30 in former bend zones 34 and 34.1. The former bend zones 34 and 34.1 extend along the length of the curved surfaces 32 and 32.1.

The anvil 14 has a curved shape to present a curved surface 36, complementary to the curved surfaces 32 and 32.1.

In use, ductile sheet material 38 is clamped between the seat or clamping surface 28 and the surface 30 of the former by clamping the former down onto the clamping surface 28 by means of the nuts 20 and studs 22, thereby bending the sheet material to have a first curved surface corresponding to that of the surfaces 28 and 30, such that a predetermined portion 38.1 of the sheet material projects beyond the former bend zone 34. The former frame is then displaced in the direction of arrow 40 about the pivotal azis 24, to displace the former 12 towards the anvil 14 for the portion 38.1 of the sheet material to bear upon the surface 36 of anvil 14. Progressive displacement of the former 12 towards the anvil 14 causes the portion 38.1 of the sheet material to bend to assume the shape of the surface 36 of anvil 14, and in the closest position of the former 30 to the anvil 14 to be clamped between the surfaces 36 of the anvil 14 and 32 of the former 12, thereby presenting a further curved surface intersecting the first curved surface such that the bend takes place along a bend zone corresponding to bend zone 34. The radii of curvature of the surfaces 30 and 32 of the former 12 being equal to each other in the bend zone 34.

Progressive bending of the sheet material 38 in apparatus 10 is shown in FIGS. 5 to 7. Upon displacement of the former 12 towards the anvil 14, the projecting portion 38.1 of sheet material 38 bears against surface 36 of anvil 14 to initiate bend zone 42 (FIG. 5) on the portion 38.1. Progressive displacement of the former 12 towards the anvil 14 causes the bend zone 42 to be displaced progressively as shown in FIGS. 6 and 7 until the portion 38.1 shown in FIG. 7, is clamped between surfaces 32 of the former 12 and 36 of the anvil 14 to present a further curved surface 44 intersecting the first curved surface 43 along the bend zone 42.

Referring to FIG. 2, reference numeral 46 generally indicates an article of a ductile sheet material 48 shaped to three dimensional shapes having curved surfaces. In this embodiment the sheet material is bent to have a curved surface 50, and is thereafter bent to have further curved surfaces 52 and 52.1 to intersect the curved surface 50 such that the bends takes place along bend zones 54 and 54.1 in which the curved surfaces meet. The radii of curvature of surfaces 52 and 52.1 and the surface 50 are equal to each other in the bend zones 54 and 54.1.

Referring to FIG. 3, reference numeral 56 generally indicates a further article of shaped ductile sheet material 58 having three dimensional curved surfaces. The sheet material 58 is provided with first curved surfaces 60 and 62, and the sheet material is bent to have further curved surfaces 60.1 and 62.1 respectively to intersect the surfaces 60 and 62 respectively along bend zones 60.2 and 62.2 respectively. Although the curved surface 60 is shown having a constant radius of curvature, the radius of curvature may progressively increase or decrease away from the bend zone.

Referring to FIG. 4, yet a further article of ductile sheet material 66 shaped to a three-dimensional shape having curved surfaces is generally indicated by reference numeral 64. The sheet material 66 is provided with a first curved surface 68, and thereafter the material is bent to have further curved surfaces 70 and 72 intersecting the surface 68 such that the bend takes place along bend zones 70.1 and 72.1 in which the curved surfaces meet. As shown in FIG. 4 the radius of curvature of the surfaces 70 and 72 vary progressively in magnitude along the bend zones 70.1 and 72.1. The surfaces 70 and 72 furthermore have zones of inflection in the region of 74 and 76 respectively.

A former 78 in FIG. 4 for shaping the surface 72 accordingly has a former bend zone generally indicated by reference numeral 80 and which has a zone of inflection in the region of 82.

Claims

I claim:

1. A method of shaping ductile sheet material to three-dimensional shapes having curved surfaces, which includes the steps of shaping a first portion of such sheet material to have a curved surface and of thereafter bending and shaping a further portion of the material to have a further curved surface intersecting the first curved surface such that the bend takes place along a bend zone in which the curved surfaces meet, the radii of curvature of the surfaces being equal to each other in bend zone.

2. A method of shaping ductile sheet material to three-dimensional shapes having curved surfaces in which the shaping of the sheet material takes place about a former shaped to have at least two curved surfaces intersecting in a former bend zone, which method includes the steps of clamping the sheet material in curved shape against a first one of the curved surfaces of the former such that a predetermined portion of sheet material projects beyond the former bend zone, of displacing the former towards an anvil having a curved shape complementary to the second curved surface of the former thereby bending and shaping the sheet material between the anvil and the second curved surface of the former to have a shape corresponding to the two intersecting curved surfaces of the former.

3. A method as claimed in claim 2, in which the former and the anvil are pivotally connected.

4. A method as claimed in claim 3, in which the bend zone in the sheet material is initiated on that portion projecting beyond the former bend zone and is progressively displaced along the said portion to the former bend zone by progressively displacing the former towards the anvil.

5. A method as claimed in claim 2, in which the radius of curvature of at least one of the curved surfaces of the sheet material varies progressively in magnitude away from or along the bend zone.

6. A method as claimed in claim 1, in which the sheet material has at least one further bend zone spaced from the first and defining the intersection of a third curved surface with the first curved surface.

7. A method as claimed in claim 1, in which at least one of the curved surfaces has a zone of inflection.

8. Apparatus for shaping ductile sheet material to three-dimensional shapes having intersecting curved surfaces and comprising a former shaped to have at least two curved surfaces intersecting in a former bend zone; clamping means adapted to clamp a length of ductile sheet material in curved shape against a first one of the said curved surfaces such that a predetermined portion of the sheet material projects beyond the former bend zone; and an anvil having a curved shape complementary to the second curved surface of the former; the former and anvil being capable of bending and shaping the sheet material between them upon displacement of the former and anvil towards each other, thereby causing the sheet material to bend around the former bend zone.

9. Apparatus as claimed in claim 8, in which the former is pivotally mounted relatively to the anvil.

10. Apparatus as claimed in claim 8 and which includes displacing means for displacing the former and anvil towards each other.

11. Apparatus as claimed in claim 8, in which the former bend zone has a zone of inflection.