Abstract: The invention provides a method of bending a sheet metal piece by means of a bending apparatus. The bending apparatus comprises a bending bar, a bending bar holder, a bottom die comprising an adjustable die bottom and a bending bottom die holder. The method of the invention is particularly suitable for bending sheet metal pieces which are shorter than the bending bar and the bending bottom die. In order to compensate for irregularities during the bending, the regions of the bending bar and bending die, respectivley, which are not influenced by the reactive forces of the sheet metal piece to be bent, are under the influence of compensating members bridging the air gap resulting between bending bar and bending die. Thus, the bending press is evenly loaded and the sheet metal work piece can be bent into an exactly predetermined bending angle.

Abstract: The invention provides a method of bending a workpiece to a predetermined bending angle, in which, in a first step, the workpiece is bent to a somewhat greater bending angle and then released. Thereafter, the amount of resilient back motion occurring after the first bending operation is measured. The adjustable die bottom is readjusted such that a bending angle would result in the next bending operation which corresponds to the desired final bending angle minus the amount of resilient back motion. After the second bending operation, the workpiece is released and the legs thereof will resiliently move back to enclose the final predetermined bending angle.

Abstract: A method of bending sheet metal pieces by means of a bending apparatus having a bending bar and a bottom die with adjustable die bottom. In a first step, the practical bending behavior of a sample sheet metal piece having a certain thickness and a certain material quality is determined and stored as a reference curve trace. In a second step, when bending further sheet metal pieces with the same thickness and having equal material quality, the effective bending behavior of each sheet metal piece is determined and compared with the stored reference curve trace. Then, the position of the adjustable die bottom is corrected on the basis of the calculated difference.

Abstract: The manipulator for sheet-metal pieces is used in conjunction with a sheet-metal working machine and has two rotatable holding members (20) displaceable in three dimensions. The holding members (20) each have both clamping tongs (22), which act on the surface of the sheet-metal piece (24) to be worked, and a clamping strip (23) exerting pressure parallel to the sheet surface. It thereby becomes possible for the sheet-metal piece to be worked, in a first working phase when it is still plane, to be grasped along two parallel edges by means of tongs and, after the first working, to be held only by means of the clamping strips.

Abstract: A bending tool for a bending press comprising an upper die member detachably secured to a vertically reciprocable ram for bending a flat metal workpiece to a predetermined depth in a lower female bending die. The bottom surface of the female bending die cavity is formed by a plurality of flat headed pins in side by side slots or bores. The heads of the pins form the bottom flat surface of a longitudinal groove which forms the bottom die cavity surface. The vertical adjustment of the pins is provided by the interfitting combination of a left side wedge assembly, a middle wedge assembly and a right side wedge assembly. The interfitting prevents displacement of any one of the supporting assemblies for the pins to assure improved bending precision.

Abstract: Bending presses equipped with the tool arrangement permit sheet blanks or metal plating to be bent in series in accordance with predetermined programs without having to perform time consuming tool exchange operations after each single operative or working step. The tool arrangement comprises a first tool and a second two-piece auxiliary tool. Both parts of the auxiliary second tool are subdivided into segments as is the case also for the first tool and the tool holding fixture or support and are supported at a hydraulic cushion. The segmental matching design of the tool holding fixture, the first tool, the auxiliary second tool and the bottom dies additionally enables the two types of tools and their associated bottom dies to be simultaneously controllably directed into a respective operative position over part of the length of the bending press.

Abstract: An easily releasable hydraulically pressurized clamping block assembly for attaching the bending tool to the ram of a folding press. A first clamping block having a recess to receive the tool abuts a bearing block at the rear thereof and is fitted with pins engaging in bores in the clamping block and in the bearing block while within the bearing block a longitudinal groove is provided which receives a hose which can be pressurized from a fluid pressure source through a control valve. Along the longitudinal groove between the above bores are holes which are fitted with springs which compress the hose when in a non-pressurized state. A modification provides pins with widened heads. Another modification uses straight pins and an intermediate block within the groove to press against the hose. Still another modification provides a groove in the ram itself rather than in a separate block.

Abstract: A bending device comprising a bar for connection at one end to a ram of a bending press, the bar having a tapered end fitting into a bending matrix fitted with a displaceable jaw. A sheet of metal placed on the matrix is bent by the bar which is forced down by the ram into a longitudinal groove of the matrix. Means are provided at the side of the matrix to determine the limiting plane of the groove and thereby control the angle and further means vary the depth of the groove.

Abstract: A machine for processing metal in sheet or plate form, especially for bending metal sheets. The machine comprises a frame with a table base on the frame and a ram which is vertically displaceable in relation to the table base. The ram has an upper tool, while a lower tool is disposed on the table base, these two tools cooperating to process the metal therebetween. The lower tool is elastically supported on the table base by means of a plurality of individual resilient supports which are arranged in a row on the table base. A plurality of intermediate parts are inserted between the table base and the supports and said parts are displaceable groupwise out of the effective region of selected supports into a neutral position, so that only the supports lying directly under the metal sheet workpiece to be processed are effective.