WO1989006210A1

WO1989006210A1 - Corner construction of thin plate

Info

Publication number: WO1989006210A1
Application number: PCT/DK1988/000223
Authority: WO
Inventors: Jørgen LØGSTRUP
Original assignee: Loegstrup Joergen
Priority date: 1988-01-07
Filing date: 1988-12-28
Publication date: 1989-07-13
Also published as: AU3032089A; DK6188D0; DK6188A

Abstract

Corner construction (1) of mitred profile elements (2), each with bent plate parts (4, 5, 6) and an additional bent end-flap (7). An angle piece (9) is inserted in each corner and fastened with rivets to the bent plate part (4). The profiled plate elements (2) and the angle pieces (9) are configured in such a manner that the angle pieces can be inserted from the inside when the plate elements (2) have been brought together.

Description

CORNER CONSTRUCTION OF THIN PLATE

The invention relates to a corner construction of the kind disclosed in the preamble to claim 1.

There are known innumerable corner constructions which can be used when plate material is to be utilized in the production of, for example, a quadrangular frame or a box of relatively thin plate material, e.g. thin sheet metal. In order for such frames or boxes to be given sufficient stiffness and strength, when heavy components are to be mounted in the frame or box, stiffening elements must be inserted in the corners, and these stiffening elements must be fastened to the plate material so that the desired stiffness is achieved.

The object of the invention is to present a new corner construction with very great stiffness, and which in a simple manner can be assembled at the place in which it is to be used. The very great stiffness shall be able to be achieved even though a relatively thin sheet metal plate is to be used as the initial material for the formation of the parts. Moreover, it is desired that the construction be configured in such a way that those sides of the plate which, after the assembly, become outer sides, can remain as completely smooth and unbroken sur¬ faces, while still allowing heavy components, a heavy gate, etc., to be solidly mounted in a simple manner. Furthermore, the parts which are to form the corner construction's assembly elements shall be identical in the abutting end portions, so that faulty assembly is excluded. Finally, the corner construction shall be configured in such a way that any working of the metal plates can be carried out before the parts are bent, hereby enabling a rational and inexpensive production to be achieved by means of automatic and possibly programme-controlled sheet metal working machines.

This is achieved by configuring the corner con¬ struction according to the invention as presented and characterized in claim 1. The angle pieces fit precisely into the worked and bent plate profiles and sit in an immovably firm manner. Mechanical in¬ fluences on the plate items are transferred to the angle pieces as forces which extend in the flat planes of the plate-formed angle pieces, and attack along the rectilinear inner and outer edges, and the stiffness achieved hereby is incredibly great. The angle pieces are secured to the first edge surface of the plate items, e.g. with rivets, so that after having been positioned and rivetted they can neither rock nor tip. The bent long sides form a solid basis for the assembly of components, doors, backplate, etc.

By configuring the corner construction according to the invention as presented and characterized in claim 2, it becomes possible to insert the angle pieces after the plate-profile items have been brought together. Thus it is possible for the whole of the assembly to be carried out "from the inside", which is of great practical significance when a box or a frame is to be assembled on site between parts which have been fixedly mounted beforehand, e.g. between two cupboards or between a cupboard and a wall. It also becomes possible herewith to erect a box or a cupboard around equipment already mounted.

If further mechanical rigidity or more possibilities of mounting of components is desired, the corner according to the invention is configured as presented and characterized in claim 3. An additional longi¬ tudinal bending increases the rigidity without giving rise to problems in the assembly, in that the parts of the corner construction can still be assembled as described above. In addition to the increased rigidi¬ ty and strength, the possibility is also increased for the provision of additional mounting holes for that equipment which is to be located in the space defined by the construction.

Suitable leg lengths of the angle pieces can be obtained by configuring the corner construction according to the invention as presented and characterized in claim 4, so that the desired strength and rigidity can always be achieved.

Sealing of the corner assembly can be achieved, if the corner construction according to the invention is configured as presented and characterized in claim 5. Moreover, it strengthens the construction further that the two end-flaps rest against each other.

By configuring the corner construction according to the invention as presented and characterized in claim 6, the angle pieces can be given further functions without reducing the effects and advantages mentioned above. The holes can be used for securing a bottom plate and/or a lid, hinges or the like for a door. None of the further functions thus require holes in the plate parts which subsequent to the assembly become outer sides of a box or a frame.

If the corner construction according to the invention is to be used in connection with comparatively broad plate items, so as for instance to constitue a deep cupboard or frame, it can advantageously be con¬ figured as presented and characterized in claim 7. The bended end-flaps are held together, thus avoiding the risk of the corner opening on the outside due to bending impacts. It is obvious that the joining together of the end-flaps also increases the strength and rigidity of the corner construction.

For certain applications, a greater degree of sealing is desired than that which can be achieved by the bent edges abutting together. A greater degree of sealing can be achieved by configuring the corner construction according to the invention as presented and characterized in claim 8. The jointing material can also be used to compensate for production tolerances or to achieve a given apperance, e.g. a marking of the abutting side surfaces should this be desirable.

The corner construction according to the invention is particularly suitable for the manufacture of a frame which comprises the four plane outer sides in a quadrangular metal box, as disclosed in more detail and as characterized in claim 9, especially if completely smooth outer sides without holes, rivet heads, screw heads, welding marks, etc., are desired. The corner construction according to the invention has been developed especially for the manufacture of frames or boxes for smaller electrical panel in¬ stallations, as disclosed in more detail in claim 10.

The invention will now be described in more detail with reference to the drawing, which shows a pre¬ ferred embodiment of the corner construction according to the invention, and where

fig. 1 shows a corner seen from inside and during assembly,

fig. 2 shows an assembled corner, also seen from inside, but where the parts of the one side are omitted but marked,

fig. 3 shows the corner seen from outside,

fig. 4 shows an angle piece on a larger scale, and

fig. 5 shows a part of a corner construction seen towards the end of one plate item, but with angle pieces inserted.

In a preferred embodiment, the corner construction is produced from a thin metal plate, e.g. an iron plate 0.5-2.0 mm thick, in the form of profile-bent items 2, which are bent after all of the shearing and blanking operations have been carried out. The profile-bent items 2 have three longitudinal edge surfaces or plate parts 4,5,6 in each side, and all bending lines are parallel and all bends are of 90° and effected towards each other, the result being a smooth and plane basic part 3 which forms the outer wall of, for example, a frame or a box, see especially fig. 3.

The end portions of the items 2 are also sheared beforehand and bent to provide a bent end-flap 7 and angle-sheared edges 8 on the plate part 4, so that two identical plate elements can be joined to form a mitred corner.

The end-flaps 7 have corners 17 cut off at an angle (see fig. 5), and the flap 7 is bent in the perpendicular direction to the remaining bends, and the end-flap is usually bent 135°, so that the flap 7 after bending forms an angle of 45° at the plate side 3, coresponding to the cut-off side 8 of the mitred corner, see fig. 1,2 and 3.

Fig. 4 shows on a larger scale and in more detail an angle piece 9 which, together with the longitudinal, bent edges 4,5 and 6, forms part of the strength- giving element in each side of a plate corner. The angle piece 9 is sheared or blanked from metal plate, e.g. iron plate with a thickness of 0.5-4 mm. Each angle piece has two legs, the outer edges of which are rectilinear and form an angle V, preferably of 90°, corresponding to the desired corner angle. The abutting edges 10 have a cut-off corner 12, so that the angle piece can easily be inserted in the corner, and so that it does not abut against the end-flaps 7 (see fig. 1) during the insertion. The angle piece 9 is provided internally with inner edges 13 parallel with the outer edges 10 and at a distance b from said edges 10. The distance b is equal to the distance between the plate parts 3 and the bent plate edge 5, see fig. 5. The internal plate edges 13 extend from the corner and can be rounded, as shown in the drawing, in that the edge continues stepwise over to the remaining inner edge 11 of each leg. The edges 10 and 13 are executed with precise tolerances, since the distance between the edges, together with the distance between the bent edge surface 5 and the plate part 3, is decisive for the rigidity of the corner construction. The angle piece 9 also has holes 14 for assembly elements, e.g. rivets 16, and can have raised tapped holes 15 for the mounting of, e.g. door hinges, said holes corresponding to similar holes 14 and 15 in the edge 4.

The first edge surface 4 can have additional holes 21, the second edge surface 5 can have holes 20, and in the third edge surface 6 or in the transition between the second and the third edge surface there can also be provided holes 22. The holes in the edge surfaces are intended for the mounting of parts, electrical components or support rails for such components.

The corner construction can be further stiffened by means of locking clamps 19 or other assembly elements or assembly methods, for example spot welding of the abutting flaps 7. Normally, this is necessary only with broader plate profiles and possibly if packing or a jointing material is placed between the abutting outer edges.

In fig. 1 is seen a corner construction according to the invention during the assembly operation. For the reason that the third edge surface 6 is shortened at the corner assemblies, in that an area 18 in each end is removed, an angle piece 9 can be inserted in the manner shown. The angle piece is introduced at an angle as shown and is tipped down into place, after which the rivets 16 (see fig. 2) are inserted and the corner is assembled and finished when an angle piece has been inserted in each side.

In the drawing is shown a corner according to the invention. It will be obvious to those familiar with the art that the ends of the profile parts 2 which are not shown must also be configured in an identical manner to those shown, in order to produce a frame or a box.

It will be obvious to those familiar with the art that the bent plate profiles 2 can be produced in any length and in any breadth, so that frames of any size can be produced, normally merely by re-setting or re- programming the automatic shearing, blanking and bending machines which are used for the sheet metal working.

Except for the edges at the side cut-offs 8, all sheared edges turn inwards in the space defind by the frames. This contributes greatly towards reducing the possibility of rust or corrosion attack, which usually starts at the sheared edges, regardless of whether they are protected by subsequent surface treatment. However, the sheared edges 8 are often covered by a door or a frontplate, so that all sheared edges can be protected against direct influences from the surrounding environment, e.g. moisture, dirt, residue, aggressive gases, mechanical influences, etc., which can contribute towards the beginning of rust or corrosion on the least protected parts, namely the sheared edges.

It is similarly obvious that instead of using an ordinary iron plate, the corner construction and herewith the subsequent frames or cabinets can be made of galvanized, laquered or other surface-treated iron or metal plate. The surface treatment can be effected before the working of the plate profiles is undertaken, or after the working, possibly before the bending operations are carried out.

Claims

C L A I M S

1. Corner construction of thin plate and of abutting plate elements (2) held together by a number of identical angle pieces (9) which are shaped with an angle (V) corresponding to the desired angle between the plane parts (3) of the plate elements, c h a r a c t e r i z e d in that

a) the plate elements (2) on each long side have two bends to the same side, each of approximately 90°, the result being a first edge surface (4) and a second edge surface (5) disposed at a distance from the plane part (3).

b) the plate edge lying between the bends is provided with a bend, thus giving rise to an end- flap (7) between the said two pairs of bands, said flap (7) having cut-off corners (17), and in that the end edge (8) of the first edge surface (4) is sheared at an angle.

c) a number of angle pieces (9) are configured in plane material and with rectilinear outer edges (10) and herewith parallel inner edges (13) at a distance (b), corresponding to the distance between the second edge surface (5) and the plane part (3), and in that

d) holes (14) are provided in the angle piece (9), and holes (14 ) corresponding hereto in the first edge surface, said holes being arranged to receive a joining element (16).

2. Corner construction according to claim 1, c h a r a c t e r i z e d in that the abutting outer edges (10) of the angle pieces (9) have a corner (12) cut-off at an angle.

3. Corner construction according to claim 1 or 2, c h a r a c t e r i z e d in that

a) the second edge surface (5) of the plate elements (2) are provided with a further bend, the result being a third edge surface (6) which is narrower than the other surfaces, said surface (6) being removed in a small area (18) at the corner, and in that

b) the inner edge parts (13) of the angle pieces (9) have an extent which is less than that area (18) which is removed from the third edge surface (6).

4. Corner construction according to claim 3, c h a r a c t e r i z e d in that the insides of the legs on the angle pieces have a rectilinear area (11) at a smaller distance from the outer edge (10) than the inner edge parts (13), and that the inner edge parts (13) constitute in the order of a third of the length of each leg.

5. Corner construction according to claim 1 or 3, c h a r a c t e r i z e d in that the end-flap (7) is bent in such a manner that it forms an angle with that plane part (3) which corresponds the half-part of the desired corner angle (V), preferably 45° so that a corner of 90° is obtained.

6. Corner construction according to any of the claims 1-4, c h a r a c t e r i z e d in that the angle pieces (9) have holes (15), preferably holes raised to the same side and provided with threads, and that there are corresponding unraised holes without threads in the first edge surface (4).

7. Corner construction according to claim 5, c h a r a c t e r i z e d in that the abutting edge- flaps (7) in a corner are held together with at least one flexible metal clamp (19), by riveting, spot welding or other sheet metal joining means.

8. Corner construction according to any of the claims 1-7, c h a r a c t e r i z e d in that a jointing material or an oblong packing of an elastic material, such as rubber or plastic is placed between the abutting bended flap-ends (7).

9. Use of the corner according to any of the claims 1-8 in the formation of a quadrangular metal box with right-angle corners, in that the plane parts (3) of the plate elements (2) constitute the sides of the box, and that the bent surfaces (4,5) constitute positions at which a possible bottom, lid or door is mounted.

10. Use of the metal box according to claim 9 for electrical installations, particularly smaller panel installations and so-called plate-encapsulated installations.