Bending angle detection device and plate bending method

Abstract

Labor required for knowing what extent of bending of a plate corresponds to what degree of angle of the bent portion is reduced. A bending angle detection apparatus ( 50 ) has a sensor ring L ( 64 ), a holder ( 62 ), bearings ( 70 ), the motor body of a servomotor ( 60 ), and a rotation angle sensor ( 102 ). The sensor ring L ( 64 ) produces a signal corresponding to whether the apparatus is contacted with a blade member plate or not. The holder ( 62 ) and the bearings ( 70 ) rotatably connect the sensor ring L ( 64 ) to a bending machine. The motor body of the servomotor ( 60 ) drives the sensor ring L ( 64 ) so that it is rotated. The rotation angle sensor ( 102 ) detects the rotation angle of the sensor ring L ( 64 ). In addition, the holder ( 62 ) and the bearings ( 70 ) connect the sensor ring L ( 64 ) to the bending machine so that the rotation axis of the blade member plate in the case where the bending machine bends the blade member plate coincides with that of the sensor ring L ( 64 ).

1 . A bending angle detection apparatus which is a bending angle detection apparatus ( 50 ) for detecting an angle of a bent portion of a plate which is bent by a bending machine ( 80 ), wherein said apparatus detects the angle in a state where the plate is attached to the bending machine. 
     
     
         2 . A bending angle detection apparatus according to  claim 1 , wherein said bending angle detection apparatus measures a direction of the plate before said bending machine bends the plate, and a direction of the plate after said bending machine bends the plate. 
     
     
         3 . A bending angle detection apparatus according to  claim 2 , wherein said bending angle detection apparatus is contacted with the plate to measure the direction of the plate before the bending machine bends the plate, and a direction of the plate after said bending machine bends the plate. 
     
     
         4 . A bending angle detection apparatus according to  claim 3 , wherein
 said bending angle detection apparatus comprises:   a signal production device ( 64 ,  66 ) which produces a signal corresponding to whether said apparatus is contacted with the plate or not;   a connecting portion ( 62 ,  70 ) which rotatably connects said signal production device to said bending machine;   a drive device ( 100 ) which drives said signal production device so that said signal production device is rotated; and   a rotation angle detection device ( 102 ) which detects a rotation angle of said signal production device, and   said connecting portion connects said signal production device to said bending machine so that a rotation axis of the plate in a case where said bending machine bends the plate coincides with a rotation axis of said signal production device.   
     
     
         5 . A bending angle detection apparatus according to  claim 4 , wherein
 said drive device has a motor ( 100 ), and   said rotation angle detection device has a sensor ( 102 ) which detects a rotation angle of a rotor of said motor, to indirectly detect the rotation angle of said signal production device.   
     
     
         6 . A bending angle detection apparatus according to  claim 4 , wherein
 said drive device has:   a motor ( 100 ); and   a buffer member ( 112 ,  116 ) which is connected between said motor and said signal production device, which transmits a torque supplied by said motor to said signal production device, and which is elastically deformed by the torque supplied by said motor.   
     
     
         7 . A method of bending a plate in which a plate ( 300 ) is bent by a bending machine ( 80 ), wherein
 springback which is produced when the plate is bent is previously measured (S 202  to S 226 ) in a state where the plate is attached to said bending machine, by a bending angle detection device ( 50 ) which is connected to said bending machine, the bending angle of the plate in the case where the plate is bent is corrected (S 260 ) based on a result of the measurement, and the plate is bent (S 262 ) based on the corrected bending angle.