A tool storage device is disposed on a side of a press brake. In the tool storage device, a lower tool holder is lifted up from lower tool holder support members, is moved forward or backward, and both end sides in a left-and-right direction of the lower tool holder are lowered after being passed through recessed portions formed on the lower tool holder support members (step (a)). The lowered lower tool holder is conveyed forward, and is positioned to a same height as a height of a lower tool mounting portion in a lower table (step (b)). The lower tool held in the lower tool holder is transferred to the lower tool mounting portion by a tool replacement device, and is mounted on the lower table (step (c)). The lower tool mounted on the lower table is returned into the tool storage device (step (d)).

A machine tool for bending a workpiece by clamping the workpiece with a die and a punch is configured to: distinguish a material characteristic of the workpiece as an actual value and a nominal value; determine an actual material characteristic during an machining operation and re-calculate an operation target value suitable for the workpiece; and bend the workpiece by operating the punch in accordance with the suitable operation target value thus re-calculated.

A machine tool for bending a workpiece by clamping the workpiece with a die and a punch is configured to: distinguish a material characteristic of the workpiece as an actual value and a nominal value; determine an actual material characteristic during an machining operation and re-calculate an operation target value suitable for the workpiece; and bend the workpiece by operating the punch in accordance with the suitable operation target value thus re-calculated.

Provided are a highly-versatile plate-like-workpiece twisting and retaining apparatus, plate-like-workpiece twisting and retaining method, and plate-like-workpiece twisting and shaping method that can give a freely-chosen twisted shape or curved shape to a plate-like workpiece with a simple, highly-versatile configuration without having to prepare a die member and that can also be applied to an integral skin. A twisting and retaining apparatus includes at least two support points that are contactable with a first surface in a twisting range of a plate-like workpiece; a plurality of pressing points that are similarly contactable with a second surface in the twisting range and that flank a line connecting the at least two support points in plan view of the plate-like workpiece; and an advance-retract driving apparatus (support unit, pressing unit) that causes at least the support points or the pressing points to advance and retract in a thickness direction of the plate-like workpiece.

A bending machine for metal sheets includes a punch arrangement that supports a set of upper bending tools, a die arrangement that supports at least one set of lower bending tools, a tool magazine of bending tools, a replacing apparatus arranged to take bending tools from the tool magazine and mount them on the punch arrangement and/or the die arrangement and vice versa, and a gripping device configured to simultaneously clasp and move a whole set of bending tools. The tool magazine comprises a plurality of supporting guides that house respective sets of bending tools and a transfer carriage arranged to house a set of bending tools and movable between an exchange position to receive from, or provide to, the gripping device a set of bending tools and a plurality of loading positions to transfer to, or receive from, a supporting guide a set of bending tools.

A press brake is provided with a hydraulic cylinder configured to move an upper table and a lower table relative to each other in a vertical direction, and a control unit configured to control a hydraulic circuit of the hydraulic cylinder, in which the control unit manages a predictor of an occurrence of an abnormality in the hydraulic circuit including a first pressure control valve configured to control a back pressure of hydraulic oil on a first port side of the hydraulic cylinder.

A press brake is provided with a hydraulic cylinder configured to move an upper table and a lower table relative to each other in a vertical direction, and a control unit configured to control a hydraulic circuit of the hydraulic cylinder, in which the control unit manages a predictor of an occurrence of an abnormality in the hydraulic circuit including a first pressure control valve configured to control a back pressure of hydraulic oil on a first port side of the hydraulic cylinder.

The invention relates to a bending angle measuring method for a bending machine (1), in particular a bending press or brake press, and the bending machine (1) has a bending tool arrangement (2) with at least one upper (3) and lower tool (4). A sheet to be formed (5) is placed in the bending tool arrangement (2). A light pattern (13) is emitted onto a section by means of a lighting device (11) of a bending angle measuring device (7), the section being a single part and surrounding a sub-region on a lateral surface of the lower tool (4) and of the sheet (5) placed in the bending tool arrangement. The light pattern (13) on the lower tool (4) and on the sheet (5) is detected by an image detecting device (10) of the bending angle measuring device (7), and a bending angle is ascertained from detected light pattern (13) by an analysis module. Furthermore, a transition portion (9) between the lower tool (4) and the sheet (5) is ascertained and, based thereon, a sub-detection region (19) in the detection range (8) of the image detecting device (10) is ascertained. The sub-detection region (19) is detected by the image detecting device (10) and the currently produced bending angle is ascertained while carrying out the bending process.

The invention relates to a bending angle measuring method for a bending machine (1), in particular a bending press or brake press, and the bending machine (1) has a bending tool arrangement (2) with at least one upper (3) and lower tool (4). A sheet to be formed (5) is placed in the bending tool arrangement (2). A light pattern (13) is emitted onto a section by means of a lighting device (11) of a bending angle measuring device (7), the section being a single part and surrounding a sub-region on a lateral surface of the lower tool (4) and of the sheet (5) placed in the bending tool arrangement. The light pattern (13) on the lower tool (4) and on the sheet (5) is detected by an image detecting device (10) of the bending angle measuring device (7), and a bending angle is ascertained from detected light pattern (13) by an analysis module. Furthermore, a transition portion (9) between the lower tool (4) and the sheet (5) is ascertained and, based thereon, a sub-detection region (19) in the detection range (8) of the image detecting device (10) is ascertained. The sub-detection region (19) is detected by the image detecting device (10) and the currently produced bending angle is ascertained while carrying out the bending process.

The invention relates to a tool handling system (1) for removing or inserting a bending tool (2) in a tool mounting (3), comprising a bending tool (2) having a gripping recess (16) and a locking device (7) that cooperates with the tool mounting (3), the locking device being deactivatable by an actuating element (10) which is arranged in the gripping recess (16) and is accessible therein, and further comprising a gripper (11) with a gripper base body (12), comprising a first gripper finger (14) arranged on the gripper base body and at least a second gripper finger (15) which is adjustable on the gripper base body (12) by means of an articulation (20). The invention is characterized in that the first gripper finger (14), when positioned in the gripping recess (16), and the adjustable second gripper finger (15), when positioned in a release position, do not contact the actuating element (10) and that the adjustable second gripper finger (15) contacts the actuating element (10) in a gripping position.