A PRESS

Abstract: A press for bending plates, comprising a frame and tools which are connected to the frame and between which the plate to be bent is inserted. In the press, the frame consists of frame parts (1a, 1b) parallel to the tools (3a, 3b), these frame parts being equal in length with the tools (3a, 3b) and each frame part being essentially constant in its cross-section over its entire length. Furthermore, the frame parts (1a, 1b) are connected so as to move in relation to each other, and the press comprises several hydraulic cylinders (5) over the length of the frame parts, these hydraulic cylinders being connected to act between the frame parts (1a, 1b) in such a manner that the tools (3a, 3b) can be pressed towards each other and correspondingly moved away from each other by means of these hydraulic cylinders.

Description: A press A press for bending plate-like objects, said press comprising a frame, elongated tools, which are connected to the frame and between which the plate to be bent is inserted, the plate being bent by pressing the tools against each other, whereby the tools and the frame form between them a gap into which the plate to be bent can be pushed; and several power units successively in the longitudinal direction of the tools for pressing the tools against each other. Different presses are typically used for bending plates, these presses being basically implemented with two different constructions. Presses typically comprise a heavy frame, which can weigh as much as tens of tons, and which is situated on the hall floor and works in the vertical direction. In this case, the lower press tool is immovably connected to the frame, and the upper tool is connected in the vertical direction to a broad and heavy steel plate, which is moved by means of hydraulic cylinders located at its ends, these cylinders being connected to two C-shaped frame parts. Irrespective of the fact that the steel plate is quite broad in the direction of the press force, the result however is that the tools bend during the pressing operation, which deteriorates the produced quality of work. Further, the construction is extremely heavy and expensive, and takes up a lot of space. Furthermore, presses are known in which the press force is produced with several power units parallel to the direction of the tool, whereby the press force is distributed more evenly and bending can be avoided to some extent. These presses typically also comprise two larger C-shaped frame parts on which the supporting element of the upper tool is mounted, whereby the upper tool is bound to bend in spite of the several presses. The problem with these solutions is still, however, that the frame structure is heavy and difficult to implement, and also expensive to manufacture. The known presses also take up a lot of space. These types of presses are known for instance from U.S. Patents 4,445,357, 4,509,357 and 5,092,151, and from German Offenlegungsschrift 1,957,052. Another disadvantage of these solutions is that when plates to be bent are treated, these plates have to be turned in different ways, which requires a lot of space, and especially when automated plate treatment is concerned, highly extensive treatment equipment or robots, which adds to the produced costs. The object of the present invention is to provide a press which is simple and easy to implement, and which is better than earlier solutions both in structural and functional characteristics. The press of the invention is characterized in that the frame is essentially similar in structure over its entire length in such a manner that the elasticity of the frame is essentially constant over its entire length, so that the bend of the frame under load is essentially the same over the length of the entire press, the tools thus remaining essentially straight. The essential idea of the invention is that such frame parts are used in the frame of the press that the elasticity of the frame is essentially constant over its entire length, so that for instance the elasticity effects and bending which a conventional press equipped with one pair of tools is subjected to, and which are caused by the load, are the same over the entire breadth of the press. Even if the frame parts connected with the different tools of the pair of tools were different from each other as far as elasticity is concerned, the elasticity effects in the longitudinal direction of the press are, however, constant, and thus the tools remain straight. According to a preferred embodiment of the invention, the cross section of the frame part of the press is similarly plate-like over its entire length. Further, an essential idea of another preferred embodiment of the invention is that the press is assembled so as to pivot on its longitudinal shaft. Thus, especially as far as automated plate treatment is concerned, it is not necessary for the dirigibility and extensiveness of plate treatment equipment and robots to be particularly high, because the press can be turned not only in relation to the press but also in relation to the plate to be bent. Furthermore, according to a third preferred embodiment of the invention, the frame of the press is formed so as to be tubular, two frame parts being connected to each other either so as to pivot on the longitudinal shaft or so as to move towards each other or correspondingly away from each other in linear motion. This type of construction is simple to manufacture, and it also constitutes a compact unit which does not require a lot of space, and to which the entire dirigibility of the press can be applied. Still, according to yet another preferred embodiment, the frame consists of successive, structurally similar C-shaped frame parts that are open on one side and short in the longitudinal direction of the press, a desired amount of these frames being secured to each other according to the required press length; and the tools of the press are connected to the ends of the C-shaped frame parts in such a manner that they can be pressed against each other by power units. This type of construction is easy to use as a modular construction as well as simple to implement, and the required press length is also easy to provide by using frame parts of a standard structure. The invention will be described in more detail in the appended drawings, in which Figure 1 is a schematic front representation of an embodiment of the press of the invention as seen from the end of the press, Figure 2 is a schematic representation of another embodiment of the press of the invention as seen from the end, Figure 3 is a schematic representation of a third embodiment of the press of the invention as seen from the end, Figure 4 is a schematic representation of a fourth embodiment of the press of the invention as seen from the end, Figure 5 is a schematic representation of a further developed embodiment of the invention, Figure 6 is a schematic representation of the embodiment of the invention shown in Figure 2 as a perspective view, Figures 7a and 7b show a C-shaped frame part used in manufacturing the frame of the press of the invention, and the cross-section of the C-shaped frame part along the line A - A indicated in Figure 7a, Figures 8a and 8b show an embodiment for implementing the power units of the press shown in Figures 7a and 7b. Figure 1 shows a press the frame of which is composed of two frame parts la and lb. The frame parts la and lb are of an arched and semi-tubular cross- section. The frame parts la and lb are connected so as to pivot in relation to each other by means of a shaft 2, whereby tools 3a and 3b located at the other edges of the frame parts la and lb, respectively, can be moved towards each other in order to bend the plate placed between them, and correspondingly away from each other. Further, press arms 4a and 4b are connected to the frame parts la and lb, a hydraulic cylinder 5 being connected between these arms so as to function as a power unit. Several press arms 4a and 4b are connected successively to both frame parts la and lb. Between these arms are correspondingly connected hydraulic cylinders, so that the pivotal power produced by the hydraulic cylinders around the shaft 2 is essentially evenly distributed over the entire length of the press. By pressing the frame parts la and lb at the side of the tools 3a and 3b towards each other in this manner, the elasticity of the frame parts la and lb due to the press force is the same over the length of the frame part. If the structure and cross-section of both frame parts are the same, the elasticity effects are also the same on both sides of the press. If the cross-section and structure of the frame parts la and lb differ from each other, the elasticity effects in the frame parts la and lb may be different, but in the same frame part they are however the same over the entire length of the press, the tools 3a and 3b thus retaining their shape in spite of the press force; thus, if they are originally straight, they also remain straight. The press according to Figure 1 can be mounted on a floor or some other bed in different ways, as long as the mounting will not affect unevenly the elasticity of the frame parts la and lb. Accordingly, it is possible for instance to secure the press to the floor by means of supporting elements attached to the swinging arms 4a and 4b when the press is to be mounted fixedly. The press can also be mounted in the vertical direction, whereby it can be supported for instance by a mounting element or a base constructed in association with the shaft 2 either solely at the floor end or also at the upper end. The frame parts la and lb are preferably manufactured of a solid material either by casting and machining or by some other method, for instance by bending from a suitable plate material. They can also be constructed in another manner by using a suitably dense ribbing, provided that the elasticity is essentially constant over the entire length of the frame part. Figure 2 shows another embodiment of the press of the invention as also seen from the end. In this embodiment, frame parts la and lb are formed to be parts which are essentially of a rectangular shape, and between which hydraulic cylinders 5 functioning as power units are connected so as to operate through press arms 4a and 4b. The frame parts la and lb are mounted so as to move in linear motion in relation to each other between supporting rolls 6. Furthermore, between tools 3a and 3b, this embodiment comprises a double tool 3c, which can be mounted for instance in the manner indicated by arrow A so as to pivot in the transverse direction of the press either by means of a separate supporting arm or other supporting structures. It is thus for instance easier to push a pre-formed piece of plate into the press by turning the double tool 3c aside and turning it back after the thicker part has been pushed through. In this embodiment, it is possible to use pairs of tools that are different in their bending effects, so that different bendings required in plate bending can be performed simply by moving the plate from between one pair of tools to between another pair of tools. When a plate is bent, one pair of tools forms a supporting structure which holds the double tool 3c in its place in such a manner that it rests against one frame part, as the tool in the other frame part bends the plate in conjunction with it. Figure 3 shows a third embodiment of the press of the invention, wherein both frame parts are formed to be essentially of a U-shape, and hydraulic cylinders 5 functioning as power units are mounted on the centre line between the frame parts la and lb. Tools 3a and 3b are connected to the ends of both claws of both frame parts la and lb, respectively, in such a manner that both edges of the frame parts form a pair of tools with each other. The frame parts can thus be moved in linear motion towards each other and away from each other, and it is possible to bend two plates simultaneously. Figure 4 shows a fourth embodiment of the press of the invention, wherein the press comprises several frame parts la - lh. The frame parts are basically plate-like or otherwise similarly straight, rigid structures, which are connected at their other ends to a central shaft 12 so as to pivot on it. Between two frame parts la and lh are connected hydraulic cylinders 5 functioning as power units, which can be used to rotate these frame parts around the central shaft 12 within the limits of the motion of the hydraulic cylinder. To the frame parts la and lh, between which the hydraulic cylinders 5 are located, is connected only one tool on the side opposite to the hydraulic cylinders, whereas two tools are connected to all the other frame parts, one tool on each side in such a manner that a pair of tools is formed between all frame parts. In this embodiment, it is possible, if desired, to mount a different pair of tools in each gap between the different frames for complicated plate bending. The pair of tools is changed simply by turning the pair of tools suitable for the bending stage close to the plate to be bent, and then by pressing the frame parts against each other with the hydraulic cylinders 5, whereby the pairs of tools rest against each other and form a supported press circle around the central shaft 12 so that the tools on both sides of the plate to be bent can have a desired effect on the plate. The simplest way to articulate this embodiment is to pivot it on the central shaft 12, whereby it is easy to control and implement. Figure 5 shows an embodiment of the press corresponding to Figure 1 mounted in such a manner that the press can be turned in order to bend a plate especially in automated plate bending. As distinct from known solutions, the press can be turned so as to adapt to the bending stage in addition to changing the paths of the robots which are treating the plate, whereby the paths and operating space required by the plate treatment robots or equipment are smaller than in the known solutions. In this figure, the press is mounted so as to pivot on a shaft 2 in such a manner that to the shaft 2 is connected a swinging arm 2a, which is turned by a separate power unit, preferably a hydraulic cylinder 7. The shaft 2 and the hydraulic cylinder 7 are connected at their one end to a support frame 8, which is secured to a base 9. Other mounting and turning methods known per se can also be applied to the invention, if so desired. Figure 6 is a schematic representation of an embodiment of the press according to Figure 2 as a perspective view. As shown in the figure, frame parts la and lb are elongated and plate-like structures, or other structures implemented in such a manner that the elasticity of each frame part is essentially constant over its entire length. The figure also shows how tools 3a and 3b and double tool 3c extend over the length of the frame parts la and lb. The figure further shows how several hydraulic cylinders 5 are connected successively by means of press arms 4a and 4b over the length of the frame parts la and lb of the press in such a manner that the produced force is essentially evenly distributed, and no significant transformations occur in the tools 3a - 3c in the pressing direction. The figure also shows supporting rolls 6 schematically as roll-like rods, which can be mounted in different ways without this having a significant effect on the invention. The supporting rolls 6 can be mounted and supported against each other for instance by means of bolts or other supporting structures extending through openings formed at appropriate intervals in the walls of the frame parts la and lb moving in the vertical direction. It is also possible to mount elongated supporting structures so as to extend through openings formed in the frame parts la and lb at suitable intervals without this having a significant effect on the elasticity of the frame parts and the operation of the press. Figures 7a and 7b show yet another embodiment of the press of the invention, which is simple and easy to implement, and by which many types of presses suited for different purposes can easily be constructed. In this embodiment, the press is constituted of C-shaped frame parts lc shown in Figure 7a as seen in the longitudinal direction of the press. This type of frame part can be structurally implemented for instance in the form of a flanged beam shown in Figure 7b as a cross- section taken along the line A - A in Figure 7a. This type of C-shaped frame part lc can easily be formed so as to be sufficiently constant in its bending properties, so that its width in the longitudinal direction of the press is quite small, for instance 10 - 40 cm. When this type of C-shaped frame parts are connected to each other adjacently, i.e. successively in the longitudinal direction of the press, a continuous press frame is thus formed, the elasticity and the bends of which under load are essentially constant. In plate bending, no significant difference can be observed in bending with widths this small. Figure 7a further shows tools 3a and 3b attached to the edges of the C-shaped frame parts lc, and a separate tool unit 13 located between them. The tool unit 13 comprises separate tools 13a and 13b directed towards the tools 3a and 3b, respectively, and power units shown in more detail in Figures 8a and 8b for moving the tools 13a and 13b between the ends of the C-shaped frame parts towards the tools 3a and 3b and, correspondingly, away from them. The tool unit 13 can be mounted in different ways in relation to the frame or the base of the press, so that it can for instance be turned away from between the tools 3a and 3b to allow the bent plate to be removed. This type of frame constructions and their use are generally known per se, wherefore they are not described in more detail here. Figure 8a is a schematic, partly sectional representation of the tool unit 13 shown in Figure 7a. The tool unit thus comprises tools 13a and 13b, and located on their both sides, frame plates 13c, between which the tools 13a and 13b are able to move in the vertical direction as seen in the figure. To the tools 13a and 13b are connected or formed separate wedge parts 14, in which wedge surfaces 14a are correspondingly connected to or formed on both of the tools 13a and 13b or solely one of them. Correspondingly, for each wedge surface or pair of wedge surfaces 14a there is a separate wedge 15, which is in contact with the wedge surfaces 14a, whereby the relative amount of wedge surfaces and wedges is always appropriate, and the pairs are in the same position in relation to each other. The wedges 15 are connected to each other by a draw arm 16, or the like, in such a manner that the position of the wedges and wedge surfaces in the longitudinal direction of the tool unit 13 is always constant, and thus the effect of the wedges 15 to the tools 13a and 13b is constant over their entire length. All the wedges are further connected to a hydraulic cylinder 17, which is located at the one end of the tool unit and is connected by means of the draw arm 16 or the like so as to pull the wedges in the longitudinal direction of the tool unit, whereby the tools 13a and 13b move outwards in the lateral direction of the tool unit and bend the plates between the formed pairs of tools 3a and 13a and correspondingly 3b and 13b, as shown in the situation of Figure 7a. The tools 13a and 13b can be restored inside the tool unit by pushing the wedges away from the hydraulic cylinder 17, whereby the springs or similar elements located between the tools 13a and 13b pull the tools towards each other. As for Figure 8b, it is a schematic representation of the tool unit shown in Figure 8a as a cross-section taken along the line B - B in Figure 8a. The invention has been illustrated in the description above and the drawings only by way of example, and it is by no means so restricted. The frame parts can be implemented in different ways, provided that their elasticity is essentially constant over the entire length of the tool connected to them. The simplest way is to use a frame part which is throughout entirely similar in its cross-section, but also lattice structures supported in different ways can be used, if necessary, provided that the produced elasticity is essentially constant. The press of the invention can be applied particularly well to automated plate bending carried out by means of robots, because the use of robots allows the plates to be held very close to the frame of the press and to be treated not only by means of the paths of the robots but also by means of the swinging motion around the longitudinal shaft of the press, if so desired. Two robots can thus be working by one press, each of which can be treating either its own plate or different bending stages of one plate in sequence, so that after certain bending stages the plate is transferred to be treated by the other robot.

Claims: Claims 1. A press for bending plate-like objects, said press comprising a frame, elongated tools (3a, 3b), which are connected to the frame and between which the plate to be bent is inserted, the plate being bent by pressing the tools (3a, 3b) against each other, whereby the tools (3a, 3b) and the frame form between them a gap into which the plate to be bent can be pushed; and several power units (5; 14, 15) successively in the longitudinal direction of the tools (3a, 3b) for pressing the tools against each other, c h a r a c ¬ t e r i z e d in that the frame is essentially similar in structure over its entire length in such a manner that the elasticity of the frame is essentially constant over its entire length, so that the bend of the frame under load is essentially the same over the length of the entire press, the tools (3a, 3b) thus remaining essentially straight. 2. A press according to claim 1, c h a r a c ¬ t e r i z e d in that the frame is of an essentially tubular cross-section. 3. A press according to claim 1 or 2, c h a r a c t e r i z e d in that the frame is composed of at least two frame parts (la, lb) in such a manner that to one frame part (la, lb) is connected at least one tool; that the frame parts (la, lb) are mounted so as to move in relation to each other so that the tools (3a, 3b) can move towards each other and away from each other; and that the elasticity of each frame part (la, lb) connected with a tool (3a, 3b) is essentially the same over its entire length. 4. A press according to claim 3, c h a r - a c t e r i z e d in that the frame of the press is composed of two frame parts (la, lb), which are essentially identical in cross-section. 5. A press according to claim 4, c h a r - a c t e r i z e d in that the frame parts (la, lb) are connected to each other at their one edge so as to pivot on a longitudinal shaft (2) of the frame; that to both frame parts (la, lb) are connected in their longitudinal direction several swinging arms (4a, 4b) in the opposite direction of the shaft (2) between them in relation to the tools (3a, 3b); and that the power units (5) are connected so as to act between two swinging arms (4a, 4b) at a time. 6. A press according to claim 4, c h a r - a c t e r i z e d in that the frame parts (la, lb) are connected so as to move in relation to each other in linear motion. 7. A press according to claim 6, c h a r ¬ a c t e r i z e d in that the frame parts (la, lb) are essentially of a U-shape and mounted symmetrically in relation to each other; that to each frame part (la, lb) are connected tools (3a, 3b) at both its U-claws; and that the power units (5) are connected to act between the frame parts (la, lb) in such a manner that the tools (3a, 3b) at both edges press against each other essentially at the same time. 8. A press according to claim 1 or 2, c h a r a c t e r i z e d in that the frame (la, lb) of the press is composed of C-shaped frame parts (lc), which are open on one side and short in the longitudinal direction of the press, several of these parts being connected successively to each other in the longitudinal direction of the frame; and that tools (3a, 3b) directed towards each other are connected to both ends of the C- shaped frame parts (lc). 9. A press according to claim 8, c h a r ¬ a c t e r i z e d in that between the tools (3a, 3b) is mounted a separate tool unit (13), which comprises other tools (13a, 13b) facing the tools (3a, 3b) secured to the C-shaped frame parts (lc), these other tools being mounted so as to move in relation to the tool unit (13), whereby the tools (3a, 3b, 13a, 13b) form two pairs of tools, between both of which a plate can be bent; and that power units are mounted to the tool unit (13) so as to act between said other tools (13a, 13b) in such a manner that these tools can be pressed towards the tools (3a, 3b) secured to the C-shaped frame parts (lc). 10. A press according to claim 9, c h a r - a c t e r i z e d in that the tool unit (13) can be turned away from between the C-shaped frame parts (lc) in order to insert or remove a plate to be bent. 11. A press according to claim 1, c h a r ¬ a c t e r i z e d in that the press comprises one central shaft (12); that several frame parts (la, lb) are connected to the central shaft (12) around it so as to pivot on the central shaft (12); that the power units (5) are connected so as to act between two of these frame parts (la, lb); and that tools (3a, 3b) are connected to the frame parts (la, lb) in such a manner that except for the gap including the power units (5), all gaps between the frame parts (la, lb) comprise a pair of tools (3a, 3b), whereby all pairs of tools (3a, 3b) can be made to press against each other simultaneously by the power units (5) . 12. A press according to claim 11, c h a r ¬ a c t e r i z e d in that all the frame parts (la, lb) are essentially similar in cross-section. 13. A press according to any one of the preceding claims, c h a r a c t e r i z e d in that the power units (5) are hydraulic cylinders. 14. A press according to claim 9 or 10, c h a r a c t e r i z e d in that the power units comprise wedge surfaces (14a) successively ' in the longitudinal direction of the tool unit (13), and successive wedges (15) in the longitudinal direction of the tool unit (13), these wedges being in contact with the wedge surfaces (14) and being connected in relation to the tool unit (13) so as to move in its longitudinal direction, and said wedges being connected so as to be immovable in relation to one another; and a hydraulic cylinder (17), which is connected so as to move the wedges (15) in relation to the tool unit (13). 15. A press according to any one of the preceding claims, c h a r a c t e r i z e d in that the press is mounted in such a manner that it can be turned around a shaft parallel to its longitudinal axis in order that the press could be turned into different positions in relation to the plate to be bent.

Inventors: ALITALO HANNU, ALITALO, HANNU
Applicants: ALITALO HANNU, ALITALO, HANNU
Application year: 1995
Main classification: B21D5
IPC codes: B21D5