Abstract: A bending apparatus reciprocates at least one of an upper table to which a punch is mounted and a lower table to which a corresponding plurality of adjacent divided dies are mounted. At least one bending angle detector is provided between the dies to detect a bending angle of the workpiece. A main body inserts the bending angle detector into a gap between the dies and withdraws the bending angle detector from the gap between the dies. A lift is biased upward by a first elastic body and is configured to be pressed downward by the workpiece at approximately a center of a groove portion of the dies. The lift includes a first engagement member. A rotor support is biased upward by two second elastic bodies having smaller biasing forces than the first elastic body. The rotor support includes second engagement members. Two rotors are provided on opposite sides of the groove portion at an upper portion of the rotor support. The two rotors include workpiece contacts that contact the workpiece.

Abstract: An angle detecting head provided with an emitter and a pair of receivers is rocked, and a bent surface of a workpiece bent by a punch and a die of a bending machine is irradiated with a measurement light from the emitter, a reflected light is received by the pair of receivers, and a bending angle of the workpiece is obtained from a peak value of the light received by the respective receivers. The angle detecting head is movable parallel to the die, is movable in a direction close to and away from the workpiece, and is movable in a direction in which the die is raised/lowered. The angle detecting head is positioned in an optimum angle measurement position of the workpiece and the bending angle is measured.

Abstract: In a detecting device main body 29 of a bending angle detecting device, a pin shaft 35 having a first engagement member 39 is normally biased upward by a first spring 41 in an approximately center position of a groove portion of a die D. In the detecting device main body 29, a rotor supporting member 47 having second engagement members 61 and 63 is normally biased by two second elastic bodies 49 having weaker biasing force smaller than that of the first spring 41. Two rotors 51 are positioned and borne to both sides of a groove widthwise direction of the die D at the upper portion of the rotor supporting member 47. A forward end of the pin shaft 35 is stopped in a lower position than the upper surface of the die by rotatively link members 43 which are engaged with the first engagement member 39 and second engagement members 61 and 63, and the two rotors 51 are positioned below the upper surface of the die.

Abstract: When a workpiece W whose bend angle is to be measured is slid and pressed on to a rotor (9) in a state where the workpiece has been caused to abut on a first supporting member (7) which is a reference face, the rotor (9) rotates about a rotation center shaft (31) provided on a second supporting member (29), so that the bend angle is measured by reading the rotation angle of the rotor 9 by a detector (39). At this time, the height position of the first supporting member (7) relative to the rotation center of the rotor (9) is adjusted so that the rotation center is positioned within a contacting range R of the workpiece W and the rotor (9). Incidentally, prior to bend angle measurement, the rotor (9) is rotated such that a projection (33) is caused to abut on a stopper (35) provided on the second supporting member (29), thereby performing a calibration. A bend angle measurement can be performed easily, quickly and accurately using a small-sized and light apparatus.