DEVICE FOR WORKING PLATE-SHAPED MATERIAL

Abstract: The invention relates to a device for working plate-shaped material, said device being provided with a frame (1) and a pair of cooperating elongated working means (2, 3). One of these working means has a stationary arrangement in the frame, whilst the other is movable in the frame, transversely to its longitudinal direction, towards and away from the working means having a stationary arrangement in the frame. Both the frame (1) and the movable means (3, 4) are each provided with a plurality of guide means (5, 9) which, when seen in the longitudinal direction of the working means, are arranged one behind the other. An endless flexible pulling means (11, 12) is passed over said guide means, such that two parts of the pulling means extend from a guide means connected with the frame or the movable means, as the case may be, towards and are passed over a pair of opposite guide means, which are connected with the movable means or with the frame, as the case may be. Furthermore the pulling means (11, 12) is fixed at one end and is at its other end connected with a driving means (14, 15), by which the pulling means can be moved in its longitudinal direction.

Description: The invention relates to a device for working plate-shaped material, said device being provided with a frame and a pair of cooperating elongated working means, one of said working means having a stationary arrangement in the frame and the other being movable in the frame, transversely to its longitudinal direction, towards and away from the working means having a stationary arrangement in the frame. Such devices are e.g. known in the shape of press brakes and guillotine shears, whereby the elongated means are respectively formed by cooperating stamps, by means of which the plate to be worked can be folded, or deflected, in the desired manner or by cooperating knives by means of which the plate can be sheared. Usually the elongated working means, which is movable transversely to its longitudinal direction, is thereby mounted on a beam, whereby driving means, usually in the shape of hydraulic setting cylinders, act on both ends of said beam. Such a beam must have a particularly heavy construction in practice, in order to oppose undesirable deformations as well as possible. Particularly with press brakes this is very important, because undesired deformations not only may have an adverse effect on the life of the working means, but also may lead to undesirable dimensional variations in the product formed. From the British Patent Specification No. 1,028,868 there is known a press whereby a working means having a movable arrangement in the frame can be moved by means of an inflatable bag extending along the length of said working means. Such a flexible bag is vulnerable, whilst besides the movement effected by means of such a bag is difficult to control accurately. The German Patent Application 3,419,123 illustrates the principle of a press wherein the two working means are movable by means of a cable wound on the two working means. One of the disadvantages of this known construction is the bad accessibility of the space between the working means. The object of the invention is to obtain a device of the above kind, wherein the above disadvantages of the known devices can be met. According to the invention this can be achieved By the characterizing features of claim 1. By using the construction according to the invention a construction can be obtained wherein the force required for moving the movable elongated working means can be transferred, distributed over the longitudinal direction of said working means, to the frame part supporting the movable working means, as a result of which undesired deformations can be avoided to a large extent. According to a further aspect of the invention use is made of electric brushless servo motors for driving the movable elongated working means. In this manner it becomes possible to control the large mechanical power required for moving the elongated working means during operation directly by electronic means. This provides a considerable simplification compared with the conventional constructions, with hydraulic drive whereby the fluid must be pressurized by means of pumps driven by electromotors or the like and must be supplied to the setting cylinders driving the elongated working means. The invention will be further explained hereinafter with reference to possible embodiments of the construction according to the invention diagrammatically illustrated in the accompanying figures. Figure 1 shows an embodiment of the device according to the invention in the shape of a press brake, partly in elevational view and partly in section, along the line A - A in Figure 2. Figure 2 shows a section of the device illustrated in Figure 1, along the line B - B in Figure 1. Figure 3 shows an elevational view of a second possible embodiment of a device according to the invention. Figure 4 shows a cross-section of Figure 3. The press brake illustrated in Figure 1 comprises a frame 1 with a lower beam 2 fixed thereto. Said lower beam 2 co-operates with an upper beam 3 extending parallel thereto for folding plates or the like, said upper beam 3 being supported by a frame part 4 which can move up and down with respect to the frame 1. To said frame part 4 there are connected, a plurality of guide means in the shape of rolls 5, which are freely rotatably and arranged one behind the other when seen in the longitudinal direction of the upper beam 3, by means of shafts 6 being secured to said frame part 4 and extending horizontally and perpendicularly to the longitudinal direction of said upper beam 3. From the Figure it will be apparent that the central axes of the shafts 6 are located one behind the other and in a horizontal plane extending parallel to said upper beam 3, when seen in the longitudinal direction of the upper beam 3. The shafts 6 are thereby provided regularly spaced along the length of the frame part 4 supporting the upper beam 3. In a similar manner a plurality of shafts 8, extending parallel to the shafts 6, are secured to a plate 7 extending parallel to the frame part 4, guide means formed by rolls 9 being freely rotatable about said shafts 8. The rolls 9 are thereby arranged in two groups, which are located on both sides of an anchoring block 10 mounted near the centre of the plate 7 and at the same level as the shafts 8. As will furthermore be apparent from Figure 1 a roll 9 connected with the frame 1 is located centrally between two rolls 5 located opposite said roll 9, when seen in plan view, and which are mounted on the frame 4 supporting the movable beam 3. To the anchoring block 10 there are secured the ends of a pair of flexible pulling means formed by belts 11 and 12. As is illustrated in Figure 1 said pulling means are alternately passed over a roll 5 and a roll 9 respectively, in such a manner that two belt parts extend from a roll 5 or a roll 9, as the case may be, in the direction of rolls 9 and 5 respectively, which are arranged opposite thereto. The end of each belt 11, 12 remote from the anchoring block is passed, by means of a pair of guide rolls 13, over a driving pulley 15 mounted on the outgoing shaft of a motor 14. The free end of each belt is furthermore wound on a drum 16. Preferably an electric, so-called brushless servo motor is used for a driving motor. To the frame plate 7 there is furthermore secured a case-shaped means 17, in which a case-shaped means 18 secured to the frame part 4 supporting the upper beam 3 can move up and down. The design of the case-shaped parts 17 and 18 with the frame parts supporting said parts is thereby such that the case-shaped parts 17 and 18 form a closed space. In said closed space there are arranged a plurality of compression springs 19, which are supported with their bottom ends on the bottom of the case-shaped part 17, and which abut with their upper ends against the upper wall of the case-shaped part 18. It will be apparent that the arrangement is thereby such that the springs tend to press the case-shaped part 18 with the frame part 4 secured thereto and the upper beam 4 upwards to a raised final position. For moving the upper beam 3 downwards in order to effect that said upper beam 3 co-operates with the lower beam 2 in the intended manner, for deflecting or folding a plate placed between the two beams 2 and 3, the two motors 14 can be put into operation, in such a manner that the belts 11 and 12 are wound on the drums 15. It will be apparent that the rolls 5 will thereby be pulled in the direction of the rolls 8 by means of the belts, as a result of which the frame part 4 with the upper beam 3 supported by said frame part 4, will be moved downwards, when seen in the Figures 1 and 2, against the action of the springs 19. Because of the arrangement of the rolls 5, evenly distributed over the length of the frame part supporting the upper beam 3, the force exerted on the plate-shaped material to be worked will be evenly applied along the entire length of the upper beam 3, as a result of which undesirable deformations of said upper beam 3 can be opposed to a large extent. When the force is released or in case the belts 11 and 12 break the springs 19 will always make sure that the frame part 4 with the upper beam 3 supported by said frame part 4 will be moved upwards, which constitutes an important safety feature, as this prevents the upper beam 3 from falling down in case of failure of the drive or the like. As already said before, a very simple drive, which can be very well electronically controlled, can be obtained when for a driving means for driving the belts 11 and 12 use is made of an electric brushless servo motor. It will be apparent, however, that also other driving means for moving the belts 11 may be used, both rotating driving motors and driving motors making a linear movement, e.g. setting cylinders. Furthermore it is also possible to use cables or chains, or similar endless means, instead of belts. Furthermore it is not necessary to make use of two belts 11 and 12 or the like, which are secured near the centre of the upper beam 3 with their ends. Possibly a single belt will do, said belt being fixed near one side of the device and being connected with a driving source near the other side of said device. In the illustrated embodiment a device has been proceeded from wherein the upper elongated working means, or folding beam 3, is arranged to be vertically movable. It will be apparent that the invention can just as well be used with a device wherein the upper working means has a stationary arrangement and wherein the lower working means can move up and down. In such a case it is also possible not to use the springs 19, which will result in a very simple construction. Figures 3 and 4 illustrate an embodiment wherein a plurality of guide means formed by rolls 20 are provided on the up-and-down movable frame part 4 of the device supporting the upper beam, said guide means being freely rotatable about their aligned central axes. Said frame part 4 can thereby move up and down between a pair of plates 7′ fixed to the stationary frame of the device. To said plates 7′ there are secured guide means formed by rolls 21, in such a manner that said rolls are freely rotatable about the axes of rotation perpendicularly crossing the axes of rotation of the rolls 20. The rolls 21 located on both sides of the up-and-down movable frame part 4 are slightly staggered with respect to each other, when seen in the longitudinal direction of the axes of rotation of the rolls 21. As will be seen in particular from Figure 3 it is possible with such an arrangement to arrange the various guide means formed by the rolls 20 and 21 which are connected with the stationary frame part and with the movable frame part closer to each other than with the embodiment according to Figures 1 and 2. In this manner an even more uniform axial distribution of the forces exerted over the frame parts in question will be obtained, by means of the flexible pulling means 22 passed over said rolls, than with the application according to Figures 1 and 2.

Claims: Device for working plate-shaped material, said device being provided with a frame (1) and a pair of co-operating elongated working means (2, 3) one of said working means (2) having a stationary arrangement in the frame (1) and the other (3) being movable in the frame (1), transversely to its longitudinal direction, towards and away from the working means (2) having a stationary arrangement in the frame (1), chararacterized in that the frame (1) and the movable means (3) are each provided with a plurality of guide means (5, 9) which, when seen in the longitudinal direction of the working means (2, 3), are arranged one behind the other, whilst an flexible pulling means (11) is passed over said guide means (5, 9), such that two parts of the pulling means extend from a guide means (9; 5) connected with the frame (1) or the movable means (3), as the case may be, towards and are passed over a pair of opposite guide means (5; 9), which are connected with the movable means (3) or with the frame (1), as the case may be, and the longitudinal axis of the pulling means (11) is situated in a plane substantially parallel to the longitudinal direction of the working means (2, 3), whilst the pulling means (11) is fixed (10) at one end and is at its other end connected with a driving means (16), by which the pulling means (11) can be moved in its longitudinal direction. Device according to claim 1, characterized in that said guide means are formed by freely rotatable rolls (5, 9; 20, 21). Device according to claim 2, characterized in that the axes of rotation of the group of rolls (21) secured to the frame (1) cross the axes of rotation of the group of rolls (20) secured to the movable means (3) perpendicularly, whereby the axes of rotation of one group (21) extend at least substantially perpendicularly to the longitudinal direction of the elongated working means (2,3). Device according to claim 3, characterized in that the axes of rotation of one group (20) extend in the longitudinal direction of the elongated working means (2, 3), said axes being in line. Device according to claim 3 or 4, characterized in that the group of rolls (20) whose axes of rotation are in line are arranged near a boundary edge of the movable means (3, 4), whilst the rolls (21) of the other group are arranged on both sides of said movable means (3, 4). Device according to any one of the preceding claims, characterized in that use is made of a pair of pulling means (11, 12), which are secured near the centre (10) of the device and which are each connected with a driving means (16) near a side of the device. Device in particular according to any one of the preceding claims, characterized in that a driving means (16) is formed by a brushless servo motor

Inventors: SLOT, TEUNIS
Applicants: SAFAN B.V.
Application year: 1990
Main classification: B30B1
IPC codes: B30B1, B21D5