FIELD OF THE INVENTION

The invention relates to the method defined in the preamble of claim 1. Furthermore, the invention relates to the press brake defined in the preamble of claim 2. BACKGROUND OF THE INVENTION

It is known from the prior art that generally the bodywork, ie. the upper beam, the lower beam and the faces, of a press brake are each conventionally made as a monolithic structure welded from steel sheets.

Especially in the case of very large press brakes, such as press brakes having a press force greater than 600tn and those which are very large in size, it becomes problematic that the welded seams are large, and the large and heavy pieces are difficult to handle and transport. Oversize transports have been necessary to deliver the items. The sheet dimensions are special dimensions, and there are only few manufacturers therefor, so parts for press brakes become expensive and the delivery time months.

OBJECTIVE OF THE INVENTION

An objective of the invention is to eliminate the drawbacks referred to above.

Especially, an objective of the invention is to disclose a method and a press brake that make it possible to avoid or at least reduce the amount of welding necessary for assembling, and reduce the size and mass of individual pieces, in which case their handling, storage, packing for transportation, transportation to in- stallation site and assembling at the installation site become easier and the costs are reduced.

SUMMARY OF THE INVENTION

The method according to the invention is characterized by what has been presented in claim 1. The press brake according to the invention is characterized by what has been presented in claim 2. According to the invention the faces, the lower beam and the upper beam are assembled in the method from separate plate, plate pile and/or bar parts including tensile elements mainly receiving tensile load, press elements receiving press loads, and transmission ele- ments between tensile elements and press elements in order to transmit forces therebetween. The .tensile elements, the press elements and the transmission elements are connected to each other by mechanical connection elements without welding.

Respectively, according to the invention, it is characteristic of the press brake that the faces, the lower beam and the upper beam are each assembled from separate plate, plate pile and/or bar parts including tensile elements receiving tensile loads, press elements receiving press loads and transmission elements between tensile elements and press elements in order to transmit forces therebetween. The tensile elements, the press elements and the transmission elements are connected to each other by mechanical connection elements without welded connections.

In one embodiment of the press brake the mechanical connection elements are clip connections, mortise and tenon connections, locking piece connections and/or screw connections. In one embodiment of the press brake a locking piece connection includes a rectangular aperture on the plate, plate pile and/or bar part and an elongated parallelepiped piece having a rectangular cross section and fitted in the aperture.

In one embodiment of the press brake the length of any plate, plate pile and/or bar part included in the body of the press brake is smaller than the length of the largest standard freight container.

In one embodiment of the press brake the length of any plate, plate pile and/or bar part included in the body of the press brake is smaller than 45FT h/c - the length of a freight container (13.56m).

In one embodiment of the press brake the press brake has a press force on the order of 600tn or more.

In one embodiment of the press brake the face includes a vertical tensile bar fitted as close to the lower beam and the upper beam as possible in order to receive the tensional loads during edging. Furthermore, the face includes a vertical back post spaced apart from the tensile bar and adapted to receive the press loads during edging. In addition, the face includes an upper lever connected to the upper end of the tensile bar and the back post in order to transmit forces be- tween the tensile bar and the back post. Additionally, the face includes a lower lever connected to the lower end of the tensile bar and the back post in order to transmit forces between the tensile bar and the back post . In one embodiment of the press brake the tensile bar is assembled from a pile of steel sheets disposed one on the other. The tensile bar may also be a bar formed by one monolithic material.

In one embodiment of the press brake the tensile bar includes upper clip connection elements at the upper end of the tensile bar on opposed sides of the tensile bar and lower clip connection elements at the lower end of the tensile bar on opposed sides of the tensile bar .

In one embodiment of the press brake the upper lever is formed by two identical upper lever plate halves on opposed sides of the tensile bar, each upper lever plate half including first apertures adapted to receive the upper clip connection elements therein.

In one embodiment of the press brake the lower lever is formed by two identical lower lever plate halves on opposed sides of the tensile bar, each lower lever plate half including second apertures adapted to receive the lower clip connection elements therein. In one embodiment of the press brake the face includes a pair of side plates provided on both sides of the back post and mounted to the back post, the tensile bar and the lower lever for sideward support of the back post. The side plates also act as covers in order to hide the back post, the tensile bar and the lower and upper lever.

In one embodiment of the press brake the face includes a body element that is supported against a base. The body element includes a vertical column to which a mounting element is mounted. The mounting element in- eludes a first tenon part that extends from the column horizontally in a first direction and can be fitted in a hole at the lower end of the tensile bar, and a second tenon part that extends from the column horizon- tally in a second direction opposed relative to the first direction, on which second tenon part the lower beam can be supported.

In one embodiment of the press brake the lower beam includes a pair of lower frame plates, each having an upper edge and a lower edge in parallel to each other with holes being disposed in the vicinity of the ends of the lower frame plates in order to receive the second tenon part in the holes. Furthermore, the lower beam includes a table mounted on the upper edges of the lower frame plates, so that the lower edging tool can be supported on the table. In addition, the lower beam includes a pair of lower oblique reaction bars in an upwards opening V-shape to each other, both being pivotally bearing-mounted at the upper end on the second tenon part. Furthermore, the lower beam includes a lower reaction lever, the ends of which are rigidly connected by locking piece connections to the lower ends of the lower oblique reaction bars in order to couple the lower ends of the oblique reaction bars to each other, wherein the lower reaction lever is formed by two planar lower reaction lever halves, the lower ends of the lower oblique reaction bars being fitted therebetween.

In one embodiment of the press brake the lower beam includes two vertical reaction levers supported on the upper edge of the lower reaction lever halves at a distance from each other and from the holes. In addi- tion, the lower beam includes wedge pieces which can be disposed between the vertical reaction levers and the lower edges of the lower frame plates. The bend compensation of the lower beam may be provided by prestressing the lower beam by the wedge pieces of a suitable size to an arc which is straightened by the effect of edging force.

In one embodiment of the press brake the lower beam includes two crowning cylinders supported on the upper edge of the lower reaction lever halves at a distance from each other and from the holes, in which case the bend compensation of the lower beam can be provided by prestressing the lower beam by the crowning cylinders.

In one embodiment of the press brake the upper beam includes an upper frame plate having a long upper edge and a long lower edge in parallel to each other, the upper edging tool being mountable on the lower edge and mounting tenons being disposed in the vicinity of the ends of the upper frame plate and protruding from the upper frame plate on both sides thereof. Furthermore, the upper beam includes an upper reaction plate on the upper edge of the upper frame plate. In addition, the upper beam includes a pair of upper oblique reaction bars in a downwards opening V-shape to each other, both being pivotally bearing-mounted at the lower end to the mounting tenons, wherein the oblique reaction bars are formed by two planar upper reaction bar halves. Additionally, the upper beam includes an upper reaction lever rigidly mounted by locking piece connections to the upper ends of the oblique reaction bars in order to couple the upper ends of the oblique reaction bars to each other.

In one embodiment of the press brake the upper beam includes two hydraulic crowning cylinders in order to provide the bend compensation of the upper beam, the cylinders being provided between the upper reaction plate and the upper reaction lever at a distance from each other and from the mounting tenons of the upper frame plate. The bend compensation of the upper beam can be provided by stressing the upper beam by the crowning cylinders to an arc which is straightened by the effect of edging force.

In one embodiment of the press brake the upper beam includes two vertical reaction levers supported between the upper reaction plate and the upper reaction lever at a distance from each other and from the mounting tenons of the upper frame plate. Wedge pieces can be disposed between the upper edge, of the upper reaction plate of the vertical reaction levers, in which case the bend compensation of the upper beam can be provided by prestressing the upper beam with the wedge pieces of a suitable size to an arc which is straightened by the effect of edging force.

LIST OF FIGURES

In the following the invention will be described in detail by means of exemplifying embodiments, with reference to the accompanying drawing in which

Fig. 1 and la axonome.trically present a front view of a first embodiment of the press brake according to the invention as seen obliquely from above, assembled in Fig. 1 and the lower beam and the upper beam detached from the faces in Fig. la,

Fig. 2 axonometrically presents a front view of the face of the press brake according to the invention as seen obliquely from above, Fig. 3 schematically presents operation of the parts of the face in the press brake during edging,

Fig. 4 presents an exploded view of the face of Fig. 2,

Fig. 5 axonometrically presents a front view of the lower beam of the press brake according to the invention as seen obliquely from above,

Fig. 5a presents a modification of the lower beam of Fig. 5 where the vertical reaction levers and the wedges of Fig. 5 have been replaced by crowning cylinders,

Fig. 6 presents an exploded view of the lower beam of Fig. 5,

Fig. 7 axonometrically presents a front view of the upper beam of the press brake according to the inven- tion as seen obliquely from above,

Fig. 7a presents a modification of the upper beam of

Fig. 7 where the crowning cylinders of Fig. 7 have been replaced by vertical reaction levers and wedges, and

Fig. 8 presents an exploded view of the upper beam of Fig. 7.

DETAILED DESCRIPTION OF THE INVENTION

Fig. 1 shows an example of a large-sized press brake wherein the bodywork can preferably be implemented by the manner according to the invention. The figure presents a press brake having a press force of 1200tn wherein the dimensions include the height of the faces of approximately 6m and the length of the lower and the upper beam of approximately 10. The longest individual plate parts are found on the lower and the upper beam and they have a length of approximately 10m, so they fit in a 40 feet freight container and are then transportable as standard size cargo. The measures are presented ^' herein as examples only to elucidate the large size of the press brake, and the invention is not bound thereto in any manner. If cargo ac- ceptability is considered as a limiting factor in dimensioning the press brake, then the largest parts may be as long as to still fit in a 45FT h/c freight container. The body of the press brake includes a pair of faces 1 at the ends of the press brake, a lower beam 2 supported to be stationary on the faces, and an upper beam 3 supported on the faces to be moved by hydraulic cylinders S vertically relative to the lower beam 2.

As described with reference to Fig. 2 to 8, the faces 1, the lower beam 2 and the upper beam 3 are each assembled from separate plate, plate pile and/or bar parts including tensile elements 4, 25, 36 receiving tensional loads, press elements 5, 20, 24, 31 receiving press loads, and transmission elements 6, 7, 26, 28, 29, 35, 37 between tensile elements and press elements in order to transmit forces therebetween. The tensile elements, the press elements and the transmis- sion elements are connected to each other by mechanical connection elements 8, 9, 10, 11, 19, 23, 27, 34, 38 without welded connections. The mechanical connection elements for connecting the parts of the body to each other may be for example clip connections 8, 9, 10, 11, mortise and tenon connections 19, 23, 34, locking piece connections 27, 38 and/or screw connec- tions. A locking piece connection 27, 38 includes a rectangular aperture on the plate, plate pile and/or bar part and an elongated parallelepiped piece having a rectangular cross section and fitted in the aper- ture.

Fig. 2 to 4 present the face 1. The face 1 includes a vertical tensile bar 4 fitted as close to the lower beam 2 and the upper beam 3 as possible. The purpose of the tensile bar 4 is to receive the tensional loads during edging. A vertical back post 5 is spaced apart from the tensile bar 4 and adapted to receive the press loads during edging, as illustrated by arrows in Fig. 3. The face has an upper lever 6 connected to the upper end of the tensile bar and the back post in order to transmit forces between the tensile bar 4 and the back post 5 and a lower lever 7 connected to the end of the back post 5 of the tensile bar 4 in order to transmit forces between the tensile bar and the back post.

Fig. 4 shows that the tensile bar 4 is assembled from a pile of elongated steel sheets 4 ¹ ...4 ⁴ disposed one on the other. The tensile bar 4 includes upper clip con- nection elements 8 at the upper end of the tensile bar on opposed sides of the tensile bar and lower clip connection elements 9 at the lower end of the tensile bar on opposed sides of the tensile bar. Fig. 4 shows further that the upper lever 6 is formed by two identical upper lever plate halves 6 ¹ , 6 ² on opposed sides of the tensile bar 4, each upper lever plate half including first apertures 10 adapted to receive the upper clip connection elements 8 therein. The lower lever 7 is formed by two identical lower lever plate halves 7 ¹ , I ² on opposed sides of the tensile bar 4, each lower lever plate half including second apertures 11 adapted to receive the lower clip connection elements 9 therein.

The face 1 additionally includes a pair of side plates 12, 13 provided on both sides of the back post 5 for sideward support of the back post. The side plates 12, 13 are mounted on the back post 5, the tensile bar 4 and the lower lever 7 for sideward support of the back post. The side plates 12, 13 also act as cover plates in order to hide the structures therebetween. The face 1 also includes a body element 14 to be supported against a base. The body element 14 includes a vertical column 15 on which a mounting element 16 is mounted, the mounting element including a first tenon part 17 that extends from the column 15 horizontally in a first direction and can be fitted in a hole 18 at the lower end of the tensile bar 4. The mounting element additionally includes a second tenon part 19 that extends from the column 15 horizontally in a second direction opposed to the first direction, on which second tenon part the lower beam 2 can be supported as shown in Fig. la and 6.

Fig. 5 and 6 show the lower beam 2 including a pair of lower frame plates 20, each having an upper edge 21 and a lower edge 22 in parallel to each other. Holes 23 have been disposed in the vicinity of the ends of the lower frame plates in order to receive the second tenon part 19 in the holes. A table 24 is mounted on the upper edges 21 of the lower frame plates 20. The lower edging tool can be installed on the table 24. In addition, the lower beam 2 has a pair of lower oblique reaction bars 25 in an upwards opening V-shape to each other. Each oblique reaction bar 25 is pivo- tally bearing-mounted at the upper end to the second tenon part 19.

Furthermore, the lower beam includes a lower reaction lever 26, the ends of which are rigidly connected by locking piece connections 27 to the lower ends of the lower oblique reaction bars 25 in order to connect the lower edges of the oblique reaction bars to each other. The lower reaction lever 26 is formed by two planar lower reaction lever halves 26 ¹ , 26 ² , the lower ends of the oblique reaction bars 25 being fitted therebetween.

The embodiment of Fig. 5 and 6 has two vertical reaction levers 28 supported on the upper edge of the lower reaction lever halves 26 ¹ , 26 ² at a distance from each other and from the holes 23. Wedge pieces 29 can be disposed between the vertical reaction levers 28 and the lower edges 22 of the lower frame plates, in which case the bend compensation of the lower beam can be provided by prestressing the lower beam by the wedge pieces 29 of a suitable size to an arc which is straightened by the effect of edging force.

In the embodiment of Fig. 5a the vertical reaction levers 28 and the wedge pieces 29 of Fig. 5 have been replaced by crowning cylinders 30 supported on the upper edge of the lower reaction lever halves 26 ¹ , 26 ² at a distance from each other and from the holes 23, in which case the bend compensation of the lower beam can be provided by prestressing the lower beam by the crowning cylinders. Fig. 7 and 8 present the upper beam 3. The upper beam 3 includes an upper frame plate 31 having a long upper edge 32 and a long lower edge 33 in parallel to each other. The upper edging tool is mountable on the lower edge 33. Mounting tenons 34 are disposed in the vicinity of the ends of the upper frame plate 31 and protrude from the upper frame plate on both sides thereof. An upper reaction plate 35 is disposed on the upper edge 32 of the upper frame plate. A pair of up- per oblique reaction bars 36 is disposed in a downwards opening V-shape to each other. Each oblique reaction bar 36 is pivotally bearing-mounted at the lower end to the mounting tenons 34. The oblique reaction bars 36 are formed by two planar upper reaction bar halves 36 ¹ , 36 ² . An upper reaction lever 37 is rigidly mounted by locking piece connections 38 to the upper ends of the oblique reaction bars 36 in order to couple the upper ends of the oblique reaction bars 36 to each other. The upper reaction lever 37 is also formed by a number of uniform plate parts. Two hydraulic crowning cylinders 39 are provided between the upper reaction plate 35 and the upper reaction lever 37 at a distance from each other and from the mounting tenons 34 of the upper frame plate. The crowning cyl- inders 39 also apply pressure on the oblique reaction bars 35. By the crowning cylinders it is possible to provide the bend compensation of the upper beam during edging. During edging, as the hydraulic cylinders press on the ends of the upper frame plate 31, the up- per frame plate 31 tends vertically to bend to an arc, in which case the bending applies a tensional force on the oblique reaction bars 36, via which the force is transmitted via the crowning cylinders 39 and the upper reaction lever 37 to the upper frame plate 31, providing a force that tends to straighten the bend. This way, the upper frame plate 31 and the upper edg- ing tool mounted on the lower edge thereof can be made to remain straight.

In the embodiment of Fig. 7a the crowning cylinders 39 have been replaced by vertical reaction levers 40 and wedge pieces 41. Two vertical reaction levers 40 are supported between the upper reaction plate 35 and the upper reaction lever 37 at a distance from each other and from the mounting tenons 34 of the upper frame plate. Wedge pieces 41 can be disposed between the vertical reaction levers 40 and the upper edge of the upper reaction plate 35, in which case the bend compensation of the upper beam can be provided by pre- stressing the upper beam with the wedge pieces of a suitable size to an arc which is straightened by the effect of edging force.

The invention is not limited merely to the exemplifying embodiments referred to above; instead, many va- riations are possible within the scope of the inven ^¬ tive idea defined by the claims.