ANGLE DETECTION METHOD FOR BENDING MACHINE, ANGLE DETECTION APPARATUS AND ANGLE SENSOR

摘要

An angle detection method for a bending machine for detecting the angle of bend of a bent work. Detection light from a light source (9) is projected to a work (W) while an angle sensor (3) is being rotated in both forward and reverse directions, and a plurality of optical sensors (11 and 13) disposed symmetrically with respect to the light source (9) receive reflected light from the work (W). The quantity of light so received is held in correlation with the rotating angle of the angle sensor (3) detected by a rotating angle detector (33), and the angle of the work (W) is calculated by an angle calculation section (35) on the basis of the peak value of the quantity of received light and the rotating angle of the angle sensor (3) corresponding to this peak value. Alternatively, the rotating angle detector (3) detects the rotating angle of the angle sensor (3) when the quantities of received light of a pair of optical sensors (11 and 13) become equal, and the angle calculation section (33) calculates the angle of the work (W) on the basis of this rotating angle. An angle detection apparatus and an angle sensor are also disclosed.