GB2406810A

GB2406810A - Method of pressing a corner

Info

Publication number: GB2406810A
Application number: GB0323589A
Authority: GB
Inventors: Peter James Andrew Diamond
Original assignee: Pudsey Diamond Engineering Ltd
Current assignee: Pudsey Diamond Engineering Ltd
Priority date: 2003-10-09
Filing date: 2003-10-09
Publication date: 2005-04-13
Anticipated expiration: 2023-10-09
Also published as: GB2406810B; IE20040409A1; GB0323589D0

Abstract

A method of pressing a shaped corner from two sheet metal pieces 5 depending from a common body 6, the pieces 5 each having at least one substantially straight end 9, the method comprising deforming the metal pieces 6 such that the substantially straight end 9 of one metal piece 5 is adjacent, and extends parallel with, the substantially straight end 9 of the other metal piece 5, placing the adjacent ends 9 of the two metal pieces 5 between inner and outer press tools 15, 17, and causing relative movement between the press tools 15, 17 such that the inner and outer tools 15, 17 press the adjacent ends 9 of the metal pieces 5 into a shaped tool corner that is defined between the two press tools 15, 17, the relative movement of the press tools 15, 17 deforming the metal pieces 5 to produce a joint between the adjacent ends 9 of the metal pieces 5. A component incorporating a shaped corner produced by the above method.

Description

METHOD OF PRESSING A CORNER

The present invention relates to a method of pressing a corner and particularly but not exclusively relates to a method of pressing a curved corner from two adjacent pieces of sheet metal depending from a common body.

It can be desirable to produce a shaped corner to a body from two adjacent pieces of sheet metal depending from the body to create a pleasing appearance to the corner and to remove any sharp edges as are typically produced at metal corners by folding operations. It is desirable to be able to produce such shaped corners without the expense of welding or the like, which can then require machining to provide an acceptable finish.

According to a first aspect of the invention there is provided a method of pressing a shaped corner from two sheet metal pieces depending from a common body, the pieces each having at least one substantially straight end, the method comprising deforming the metal pieces such that the substantially straight end of one metal piece is adjacent, and extends parallel with, the substantially straight end of the other metal piece, placing the adjacent ends of the two metal pieces between inner and outer press tools, and causing relative movement between the press tools such that the inner and outer tools press the adjacent ends of the metal pieces into a shaped tool corner that is defined between the two press tools, the relative movement of the press tools deforming the metal pieces to produce a joint between the adjacent ends of the metal pieces.

Preferably the method produces a shaped corner that is curved when viewed in plan, that is when viewed generally on the axis of the corner.

Preferably the method produces a corner that curves smoothly from the local plane of one metal piece to the local plane of the other metal piece.

Preferably the method produces a curve that is of constant radius.

Preferably the method produces a shaped corner that is curved when viewed from the side, that is when viewed generally perpendicularly to the axis of the corner.

Preferably the sheet metal pieces are positioned such that there is an angle of between 0 and 180 between the local planes of the metal sheet pieces. Most preferably the sheet metal pieces are positioned such that there is an angle of substantially 90 between the local planes of the sheet metal pieces.

Preferably the method comprises an initial step of punching or cutting a plate to define a body and depending flaps, and a further step of folding the flaps through 90 , adjacent flaps of the plate comprising the two adjacent metal pieces.

Preferably the plate comprises a quadrilateral. Preferably the plate comprises four corners, each defined by respective adjacent folded flaps.

Preferably the punching or cutting step punches a substantially rectangular plate.

Most preferably the punching or cutting step produces a substantially rectangular plate and a quadrilateral cut-out from each corner of the rectangular plate. Preferably the punching or cutting of the plate is simultaneous with the punching or cutting of the cut-outs from each corner of the plate.

Preferably the punching or cutting step produces a square cut-out. Each flap is defined between two respective cut-outs.

Preferably the folding step folds each flap of the plate along a respective fold line that is aligned with an inner margin of a respective cut-out.

The fold lines, between them, define a rectangle on the plate, the margins of which are aligned with the inner margins of the cut outs.

Preferably, the folding step produces a curve at the lower margin of each flap, the curve extending from the respective fold line of each flap into the local plane of the respective flap. Preferably the local plane of each flap is outwardly spaced from the respective fold line by the curve at the lower margin of the flap.

Preferably the method further comprises a chamfering step wherein the straight ends of each flap are chamfered prior to the pressing step, such that the joint is formed between adjacent chamfered ends of the flaps.

Preferably the method further comprises a step after the pressing step, wherein the metal pieces are coated using a dip process. This improves the joint between the metal pieces.

According to a second aspect of the invention there is provided a component comprising a shaped corner produced by the method of the first aspect of the invention.

Preferably the component comprises a cabinet, panel, lid or door.

Preferably the component is substantially quadrilateral, at least one of the corners of the quadrilateral comprising a shaped corner produced by the method of the first aspect of the invention.

Preferably the quadrilateral comprises four such shaped corners.

Other aspects of the present invention may include any combination of the features or limitations referred to herein.

The present invention may be carried into practice in various ways, but embodiments will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 is a plan view of a blank used in the method of the current invention; Figure 2 is a an expanded view of part of the blank of Figure 1; Figure 3 is a side view of the expanded part of the blank of Figure 2; Figure 4 is a plan view of the blank of Figures 1 to 3 in a press with the press tools in a first condition; Figure 5 is a view corresponding to Figure 4 but showing the press tools in a second condition; Figure 6 is a plan view of a shaped corner produced in accordance with the method of the present invention; Figure 7 is an end view of the shaped corner of Figure 6; and Figure 8 is a sectional view through line A-A of Figure 6.

Referring initially to Figures 1 to 3 a substantially rectangular blank 1 of a steel material comprises a cut-out 3 at each corner of the blank 1. The blank 1 and the cut-outs 3 are formed from a single punching or cutting operation using, for example, a CNC turret punch. The blank could be formed from any suitable metal material.

The cut-outs 3 are of square shape and serve to define two pairs of opposed oblong flaps 5, each flap 5 being located between two respective adjacent cut-outs 3. Each flap 5 comprises two opposed ends 9. The flaps 5 of one pair are shorter than the flaps 5 of the other pair due to the plate 1 being of rectangular shape. The ends 9 of the flaps 5 are substantially straight. By substantially straight we include a slightly curved or serrated end 9 provided that the ends 9 of adjacent flaps 5 mesh together when pressed as described below.

As can best be seen from Figure 2, the ends 9 of each flap 5 are chamfered 11. This chamfering is achieved in known manner using the same punching or cutting operation as set out above to produce the plate 1 and cut-outs 3.

The flaps 5 are then folded through 90 along fold lines 13 using a pressing operation as is well known in the art but using a tool having a lower edge that is curved rather than sharp edged. The fold lines 13 together define a rectangle on the plate 1, the margins of the rectangle forming the inner margins of the flaps 5 themselves. Because the lower edge of the folding tool is curved, the part of each flap 5 adjacent the inner margin of the respective flap 5, where each flap 5 joins the plate 1, curves outwardly from the plate 1 to define a smooth curve between each flap 5 and the plate 1 rather than a sharp edge between each flap 5 and the plate 1.

When the folding operation is complete, the plate 1 comprises a rectangular body 6 and four outer upturned flaps 5 the local planes of which are substantially perpendicular to the plane of the plate body 6.

The local plane of each flap 5 is outwardly spaced from the periphery of the plate body 6 by the curved fold between the plate body 6 and the respective flap 5.

Each substantially straight end 9 of the flaps 5 is adjacent and, parallel with the end 9 of the adjacent flap 5 but spaced a small distance therefrom to define a space 14. The space 14 is formed between adjacent ends 9 partly because of the chamfer 11 on each end 9, and partly because the local plane of each flap 5 is outwardly spaced from the respective fold line 13 by virtue of the curved fold. It will be appreciated that, during the folding process, the curved fold between the plate body 6 and each flap 5 has the effect that the adjacent ends 9 of adjacent flaps 5 close together to a greater extent than would be the case if the each flap 5 were not folded to define a curve between the plate body 6 and the respective flap 5. The plate 1 thus comprises four corners 7 each defined by two adjacent ends 9.

One corner 7 of the plate 1 is then placed in a press between an inner press tool 15 and an outer press tool 17 so that the adjacent ends 9 of that corner 7 are centrally located between the press tools 15, 17 as shown in Figure 4. The inner press tool 15 has a curved face 19 to engage the inside of the two adjacent flaps 5, and the outer press tool 17 has a curved face 21 to engage the outside of the two adjacent flaps 5.

The tools 15, 17 comprise part of a press that is operable to cause relative movement between the tools 15, 17 such that the space between the curved faces 19, 21 can be made to increase and decrease as required. This can be achieved by each tool 15, 17 being movable and controlled, for example, by a respective hydraulic ram (not shown). It would, however, be possible for one of the tools 15, 17 to be fixed, whilst the other tool 15, 17 was movable.

The relative movement between the press tools 15 and 17 is such that when the press tools 15, 17 are at their closest position, there is a curved channel of uniform cross section defined between the curved faces 19, 21, the channel being approximately the thickness of each upturned flap 5.

When a corner of the plate 1 has been placed between the inner and outer press tool 15, 17, as shown in Figure 4, the press is operated such that the press tools 15, 17 move towards one another in the direction of arrows 23, 25 so that the width of the channel defined between the curved faces 19, 21 decreases. The corner 7 of the plate 1 is thus sandwiched between the tools 15, 17.

The outer tool 21 causes local deformation of the ends 9 of the two flaps 5 so that the radially outermost part of the ends 9 begin to take on the curved shape of the outer tool 21. The deformed material deforms into the space 14 between the adjacent ends 9 so as to gradually fill the space 14.

Further movement of the tools 15, 19 further deforms the ends 9 and deforms the region of the flaps 5 adjacent the ends 9 so that the space 14 is filled. The outer tool 21 then deforms the flaps 5 further to push the flaps 5 into engagement with the inner tool 15.

The tools 15, 17 continue moving towards one another and continue to deform the flaps 5 until the tools 15, 17 reach the end position shown in Figure 5 wherein the channel of uniform width is defined between the tools 15, 17. The regions of the flaps 5 adjacent the ends 9 completely fill the channel between the tools 15, 17 so that the corner 7 has taken on the curved shape of the radially inner and outer curves of the channel.

The corner 7 of the plate 1 thus comprises a smooth, constant radius curve between one flap 5 and the adjacent flap 5 when viewed in plan as shown in Figure 6. The chamfered ends 9 of the adjacent flaps 5 have been forced together under such pressure that a tight, rigid joint 26 has been formed between the ends 9 of the adjacent flaps 5. This joint 26 has sufficient strength that no further processing steps, such as fabrication using welding or the like, need be taken to otherwise join the flaps 5 together.

The remaining three corners 7 of the plate 1 can be pressed in the same way as described above in relation to the first corner 7. When this has been completed, finishing steps can be taken which may include a dip coating of the plate 1, or painting of the plate 1.

It is envisaged that the plate 1 having the four smooth, curved, joined corners 7 would be used on lamp post pillars to form lids or doors.

However, it will be appreciated that other components may also be formed using the above described method.

It would also be possible to vary the shape of the tools 15, 17 so as to press the corners 7 of the plate into different shapes. Such shapes may be non-constant radius curves or a number of joined, angled straight lines, or a mixture of curves and straight lines. Furthermore, the angle between the planes of adjacent flaps 5, whilst described above as being substantially 90 , could theoretically range between 0 and 180 . This would enable different shaped components to be manufactured as required. For example the component could be manufactured from a triangular or hexagonal plate.

Claims

1. A method of pressing a shaped corner from two sheet metal pieces depending from a common body, the pieces each having at least one substantially straight end, the method comprising deforming the metal pieces such that the substantially straight end of one metal piece is adjacent, and extends parallel with, the substantially straight end of the other metal piece, placing the adjacent ends of the two metal pieces between inner and outer press tools, and causing relative movement between the press tools such that the inner and outer tools press the adjacent ends of the metal pieces into a shaped tool corner that is defined between the two press tools, the relative movement of the press tools deforming the metal pieces to produce a joint between the adjacent ends of the metal pieces.

2. The method of claim I wherein the method produces a shaped corner that is curved when viewed in plan, that is when viewed generally on the axis of the corner.

3. The method of claim 2 wherein the method produces a corner that curves smoothly from the local plane of one metal piece to the local plane of the other metal piece.

4. The method of claim 3 wherein the method produces a curve that is of constant radius.

5. The method of any one of the preceding claims wherein the method produces a shaped corner that is curved when viewed from the side, that is when viewed generally perpendicularly to the axis of the corner.

6. The method of any one of the preceding claims wherein the sheet metal pieces are positioned such that there is an angle of between 0 and 180 between the local planes of the metal sheet pieces.

7. The method of claim 6 wherein the sheet metal pieces are positioned such that there is an angle of substantially 90 between the local planes of the sheet metal pieces.

8. The method of any one of the preceding claims comprising an initial step of punching or cutting a plate to define a body and depending flaps, and a further step of folding the flaps through 90 , adjacent flaps of the plate comprising the two adjacent metal pieces.

9. The method of claim 8 wherein the plate is punched or cut so as to comprise a quadrilateral.

10. The method of claim 9 wherein the plate is punched or cut so as to comprise four corners, each defined by respective adjacent folded flaps.

11. The method of claim 9 or claim 10 wherein the punching or cutting step punches a substantially rectangular plate.

12. The method of claim 11 wherein the punching or cutting step produces a substantially rectangular plate and a quadrilateral cut-out from each corner of the rectangular plate.

13. The method of claim 12 wherein the punching or cutting of the plate is simultaneous with the punching or cutting of the cut-outs from each corner of the plate.

14. The method of claim 12 or claim 13 wherein the punching or cutting step produces a square cut-out.

15. The method of any one of claims 12 to 14 wherein each flap is defined between two respective cut-outs.

16. The method of any one of claims 8 to 15 wherein the folding step folds each flap of the plate along a respective fold line that is aligned with an inner margin of a respective cut-out.

17. The method of any one of claims 8 to 16 wherein the folding step produces a curve at the lower margin of each flap, the curve extending from the respective fold line of each flap into the local plane of the respective flap.

18. The method of claim 16 or claim 17 wherein the local plane of each flap is outwardly spaced from the respective fold line by the curve at the lower margin of the flap.

19. The method of any one of claims 8 to 18 further comprising a chamfering step wherein the straight ends of each flap are chamfered prior to the pressing step, such that the joint is formed between adjacent chamfered ends of the flaps.

20. The method of any one of the preceding claims further comprising a step after the pressing step, wherein the metal pieces are coated using a dip process.

21. A component comprising a shaped corner produced by the method of any one claims 1 to 20.

22. The component of claim 21 comprising a cabinet, panel, lid or door.

23. The component of claim 21 or claim 22 wherein the component is substantially quadrilateral, at least one of the corners of the quadrilateral comprising a shaped corner produced by the method of any one of claims 1 to 20.

24. The component of claim 23 wherein the quadrilateral comprises four such shaped corners.

25. A method substantially as described herein with reference to the accompanying drawings.

26. A component substantially as described herein with reference to the accompanying drawings.