Abstract: In bending angle detection, a linear projected light image formed on the surface of a workpiece is photographed by a photographing device; the actual inclination angle of a specimen is stored as data in correspondence with the inclination angle and position of the specimen in an image; and the bending angle of the workpiece is obtained by accessing the data, with the inclination angle and position of the linear projected light image in an image produced by photographing. In main straight line extraction, main pixels are obtained from the distribution of the brightness of pixels aligned on specified axes and a main straight line is obtained from a plurality of main pixels. For extracting only a necessary straight line from an image including unnecessary straight lines, the photographing device is so disposed as to photograph a lower bender and a second straight line from the bottom end of the image is extracted.

Abstract: For starting bending of a workpiece, a provisional drive end for a ram is computed from information such as processing conditions for the workpiece input through a processing (condition input section and the relationship between the target bending angle for the workpiece and the springback angle of the workpiece stored in a springback data section. The ram is driven to the provisional drive end and then the bending angle of the workpiece is measured thereat by an angle measuring unit. Thereafter, a final drive end for the ram is obtained from (i) the measured bending angle, (ii) the relationship between the bending angle of the workpiece and the amount of driving the ram stored in a bending angle vs. driving amount data section, and (iii) the relationship between the target bending angle for the workpiece and the springback angle of the workpiece stored in a springback data section. The ram is driven to the final drive end thus obtained to complete the bending operation.

Abstract: During the process of bending a workpiece, actual load exerted on the workpiece and displacement are sampled and the bending stress to displacement relationship is obtained from the sampling data and data on the actual thickness of the workpiece. From the bending stress to displacement relationship, a material characteristic value (e.g., yield stress) which indicates the condition of the material of the workpiece is obtained. Then, a bending angle correction amount is obtained from the material characteristic value, using a data table concerning the material characteristic value to bending angle relationship. From the bending angle correction amount thus obtained, a correction depth amount is obtained. The correction depth amount is added to a preset reference depth amount to obtain a final depth amount according to which bending is performed.

Abstract: According to data from an NC device 10, a processing factor specifying section 13 specifies processing factors having effect on the bending angle. A tolerance setting section 14 sets a tolerance for each specified processing factor and a bend grouping section 15 classifies bends into groups using the tolerances. Then, a correcting condition setting section 16 establishes correcting conditions and a correction data computing section 17 computes correction data for depth according to data representative of the actual depth of an acceptable bend so as to meet the correcting conditions. Based on the correction data, a process data modifying section 18 modifies data representative of the processes of a bending operation. In this way, depth for a bend the angle of which has not been measured can be corrected based on the correction value for depth for another bend the angle of which has been measured.

Abstract: In bending angle detection, a linear projected light image formed on the surface of a workpiece is photographed by a photographing device; the actual inclination angle of a specimen is stored as data in correspondence with the inclination angle and position of the specimen in an image; and the bending angle of the workpiece is obtained by accessing the data, with the inclination angle and position of the linear projected light image in an image produced by photographing. In main straight line extraction, main pixels are obtained from the distribution of the brightness of pixels aligned on specified axes and a main straight line is obtained from a plurality of main pixels. For extracting only a necessary straight line from an image including unnecessary straight lines, the photographing device is so disposed as to photograph a lower bender and a second straight line from the bottom end of the image is extracted.

Abstract: In bending angle detection, a linear projected light image formed on the surface of a workpiece is photographed by a photographing device; the actual inclination angle of a specimen is stored as data in correspondence with the inclination angle and position of the specimen in an image; and the bending angle of the workpiece is obtained by accessing the data, with the inclination angle and position of the linear projected light image in an image produced by photographing. In main straight line extraction, main pixels are obtained from the distribution of the brightness of pixels aligned on specified axes and a main straight line is obtained from a plurality of main pixels. For extracting only a necessary straight line from an image including unnecessary straight lines, the photographing device is so disposed as to photograph a lower bender and a second straight line from the bottom end of the image is extracted.

Abstract: It is an object to provide a bending angle detecting system for a press brake which can perform high precision bending process without employing a special die, The bending angle detecting system includes a sensor (20) provided on a back stop (8) for determining a bending position of a workpiece (7) to be subject to the bending process, and means for controlling a lower limit position of a punch (6) based on an angle signal detected by the sensor (20).

Abstract: An apparatus for controlling a press brake is advantageously employable for a press brake for which a high operational efficiency and a high working accuracy are required. In response to inputting of working conditions inclusive of a target bending angle for a plate, the apparatus calculates displacement of a load active on a stationary table and a movable table, automatically calculates a quantity of crowning to be adjusted based on results derived from the foregoing calculation and then calculates the present position assumed by the movable in additional consideration of the quantity of crowning to be adjusted, based on results derived from the aforementioned calculations. The press brake accurately bends the plate based on the thus derived quantity of crowing to be adjusted and the present position assumed by the movable table without an occurrence of malfunction of so-called intermediate opening of the bent plate.

Abstract: This invention relates to a tool position controller of a bending machine which can control a bending angle at an arbitrary portion during a bending work. The upper part of this controller is divided into two plates (5a,5a) by groove in a longitudinal direction. The controller includes a die (5) which has a reversed plate support (9) fitted inside a groove (5b) defined between these two plates, die push-up means (10, 11, 12) disposed at at least one position in the longitudinal direction of the die below the die, and feed quantity control means (13, 14, 15) for controlling the feed quantity of the die push-up means on the basis of a machining condition that has been in advance inputted. A work (40) is held under pressure between a punch (8) fitted to the tip of a ram (7) moved vertically by a pressure holding cylinder (6) and the reversed plate support (9) described above and is subjected to the bending work when the die is pushed up through the push-up means.

Abstract: A press brake adapted to apply bending on metal blanks in the form of a sheet or plate includes a plurality of die assemblies located on a die holder at intervals of a predetermined distance in the direction perpendicular to the logitudinal direction of a bed of the press brake. The die holder is mounted on the bed movably in the direction perpendicular to the longitudinal direction of the bed. Each of the die assemblies is provided with an upper die and a lower die which are associated with each other and movable vertically towards and away from each other. The press brake further includes a pair of front and inside stoppers located on the front side and the inner side of the press brake body, respectively, so as to be movable freely towards and away from each other and pass through a space between the upper and lower dies.