Kabushiki Kaisha Komatsu Seisakusho

Komatsu Corporation

Toshiro Otani

Toshiyuki Ooenoki

Shigeru Tokai

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. In setting a bending angle detecting position, a potential bending step where the bending angle detection of the workpiece might be performed is calculated from simulation data on the bending state of the workpiece in each bending step.

Bending angle detector and straight line extracting device for use

Bending machine

Bending angle detecting position setting device

A springback angle measuring instrument for V-bending designed to detect the springback angle of a workpiece in such a way: A bending angle .theta..sub.1 of the workpiece is detected when an upper bender is lowered to an unloading starting position, and the instantaneous position of the upper bender and pressure imposed on the workpiece are detected while the upper bender being lifted at a very slow speed. The increment of the bending force per unit lifting distance of the upper bender is calculated and the bending angle of the workpiece at a point at which the increments of the bending force converge on a certain value is detected. Based on data on the bending angle and bending force obtained after this point, the relationship between the bending angle and the position of the upper bender and the relationship between the bending force and the position of the upper bender are respectively, approximated to a linear expression. The position of the upper bender where the bending force is zero is calculated from the linear approximate expression, and a bending angle .theta..sub.4 of the workpiece for this position is estimated. The bending angle .theta..sub. 1 for the unloading starting position is subtracted from the bending angle .theta..sub.4 to obtain the springback angle of the workpiece.

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Hirakata, Japan

Toshiro Otani