Bending angle measuring apparatus and method for measuring a bending angle by means of the bending angle measuring apparatus

A method for determining a bending angle of a sheet metal part comprising:

• providing a bending angle measuring device comprising an illumination device comprising at least one light source, an optical detector comprising a light-detecting surface, and an axisymmetric body comprising a central axis and an axisymmetric reflecting surface;
• deforming the sheet metal part using a bending machine to form a bending edge on the sheet metal part between a first flank and a second flank of the sheet metal part;
• aligning the central axis of the axisymmetric body parallel to the bending edge;
• and
• determining the bending angle of the first flank and the second flank relative to one another by at least the following steps:
• emitting a first light beam from the illumination device;
• reflecting the first light beam on a surface of the sheet metal part in a right angle as viewed in a frontal view to the central axis to form a second light beam;
• reflecting the second light beam on the axisymmetric reflecting surface of the axisymmetric body to form a third light beam aligned parallel to the central axis of the axisymmetric body and thus parallel to the bending edge;
• deflecting the third light beam either directly or by way of further deflection onto the light-detecting surface of the optical detector;
• recording of the third light beam by the optical detector;
• evaluating the third light beam recorded by the optical detector;
• and
• calculating the bending angle of the first flank and/or the second flank of the sheet metal part.

A bending angle measuring device for a bending machine for bending a sheet metal part, the sheet metal part having a first and a second flank and a bending edge located between the first and the second flanks, wherein the bending angle measuring device comprises:

• an illumination device comprising at least one light source,
• an optical detector comprising a light-detecting surface, and
• at least one axisymmetric body comprising an axisymmetric reflecting surface and a central axis, wherein the central axis of the axisymmetric body is aligned parallel to the bending edge,
• wherein a first light beam transmitted by the illumination device is reflected from a first flank of the sheet metal part, and is directed onto the axisymmetric reflecting surface of the axisymmetric body in the form of a second light beam, and is directed onto the optical detector in the form of a third light beam, and
• wherein another first light beam transmitted by the illumination device is reflected from a second flank of the sheet metal part, and is directed onto the axisymmetric reflecting surface of the axisymmetric body in the form of another second light beam, and is directed onto the optical detector in the form of another third light beam, and
• wherein the optical detector and the axisymmetric body are configured such that the bending angle of the first and the second flank of the sheet metal part is calculable by evaluation of the third light beam corresponding to the first flank and the other third light beam corresponding to the second flank recorded by the optical detector.