The invention relates to a lower tool (1) having a longitudinal-offset measuring device (2), which lower tool (1) is part of a bending tool arrangement for use in a bending press. The lower tool (1) has a tool body (3) having a longitudinal extension (4), in which longitudinal extension (4) a bending recess (5) is provided. The bending recess (5) extends from an upper flat side (6) of the tool body (3) into the latter and is formed at least by two contact surfaces (7). The transition from the upper flat side (6) into the bending recess (5) forms a contact edge (8), which contact edge (8) forms a contact line (9) in the longitudinal extension (4). A sensor (10) for determining a longitudinal offset (18) is arranged in the region of the contact line (9), wherein a sensing portion (11) of the sensor (10) is oriented in the direction of a metal sheet (16) to be bent.

A metal plate bending device, including a lower die having a main body including a pair of arc-shaped cross-sectional recesses formed on an upper surface in a symmetric design with respect to a center line, and swingable members swingably received in said recesses respectively. An upper die is arranged above said lower die movably along said center line relative to said lower die, wherein said upper die is moved toward a metal plate mounted on said lower die causing a press-push force to said metal plate to, causing said swingable members to swing and bend said metal plate along said center line. A movable plate is slideably in planar contact with a flat upper surface of the swingable members and is a flat supporting surface. During bending, said movable plate is slideable with respect to said swingable member, and is moved together with said metal plate.

A bending tool includes movable dies having a bending line of a punch and a workpiece therebetween. A support member supports the movable dies in a manner rotatable into directions opposite to each other in accordance with bending of the workpiece by the punch. A body supports the support member in a manner reciprocatable in a movement direction of the punch in accordance with bending of the workpiece by the punch. The movable dies have respective reception faces for the workpiece, respective bending side end portions, and respective convex circular faces. The support member has respective concave circular faces which slidably fit respectively with the convex circular faces. The bending side end portions engage with each other in accordance with bending of the workpiece by the punch. A sliding portion moves in a pressing direction of the punch relative to the body in accordance with bending of the workpiece.

The invention relates to method for estimating a shortening length of a sheet metal workpiece which is bent about n bending axes and by n bending angles alpha, comprising the following method steps, wherein

the bent sheet metal workpiece comprises n+1 limbs extending along a straight extension line and n curved regions which are produced by bending the sheet metal workpiece and extend between two adjacent limbs.

The invention relates to a lower tool (1) having a longitudinal-offset measuring device (2), which lower tool (1) is part of a bending tool arrangement for use in a bending press. The lower tool (1) has a tool body (3) having a longitudinal extension (4), in which longitudinal extension (4) a bending recess (5) is provided. The bending recess (5) extends from an upper flat side (6) of the tool body (3) into the latter and is formed at least by two contact surfaces (7). The transition from the upper flat side (6) into the bending recess (5) forms a contact edge (8), which contact edge (8) forms a contact line (9) in the longitudinal extension (4). A sensor (10) for determining a longitudinal offset (18) is arranged in the region of the contact line (9), wherein a sensing portion (11) of the sensor (10) is oriented in the direction of a metal sheet (16) to be bent.

A metal plate bending device, including a lower die having a main body including a pair of arc-shaped cross-sectional recesses formed on an upper surface in a symmetric design with respect to a center line, and swingable members swingably received in said recesses respectively. An upper die is arranged above said lower die movably along said center line relative to said lower die, wherein said upper die is moved toward a metal plate mounted on said lower die causing a press-push force to said metal plate to, causing said swingable members to swing and bend said metal plate along said center line. A movable plate is slideably in planar contact with a flat upper surface of the swingable members and is a flat supporting surface. During bending, said movable plate is slideable with respect to said swingable member, and is moved together with said metal plate.

Two press brake machines each using a single, central hydraulic actuator are provided. The press brake machines are configured to operate separately or in tandem, depending upon a size of a sheet metal workpiece to be deformed. A locking device that may include an upper connecting block and a lower connecting block is provided on each of the at least two press brake machines to allow the machines to interlock when the machines are adjacent to one another and are operating in tandem. The upper connecting block may be L shaped to help provide the interlocking. Interlocking of the press brake machines during tandem operation helps prevent distortion that can occur in the upper and lower portions of the ram due to the press brake machine's use of a single, central hydraulic actuator.

[Problem] To provide a bending device with a novel structure capable of efficiently bending a metallic plate without scratching or denting the plate. [Solution] A device (10) for bending a metallic plate (W) mounted on a pair of movable plates (35, 35) by applying pressing force to the metallic plate by an upper die (20) along a central axis (X), wherein against the biasing force of a coil spring (45), the movable plates move with the extension of the metallic plate during bending, and therefore the metallic plate is not scratched. The upper surface of each of the movable plates is a perfect flat surface, and therefore does not dent the metallic plate being subjected to the pressing force by the upper die. When the pressing force and the load of the metallic plate are removed after the completion of bending, swing members return to the original position thereof, and the movable plates are also returned to the original position thereof by the biasing force of the coil spring, with top parts (42) of fastening members (41) coupling the movable plates to fixed plates (38) functioning as a stopper and holding the movable plates at the original position.

A die for a bending or folding device includes a base; at least one pair of bending beams mounted therein, symmetrical to a central plane, so as to pivot passively about axes, which form a flat rest surface in the base position and a V-shaped base cavity in the folding position; at least one return element for each beam acting on the beam towards base position; at least one slide for each beam. Two slides in each case rest on the beams in base position symmetrically to the central plane and form a flat rest surface for a workpiece with flat rest sections, which can slide transversely to the axis with a workpiece to be processed. A support is fixed on the slide, in base position and the slide rests on a base stationary support point and is free of force and lifted off the point in folding position.