| 摘要 |
The movable blank-holder (16) of a bending press comprises a series of segments (26, 28) and a pair of motor-driven carriages (42) each of which has an entraining member (44) which can selectively engage and release the segments (26, 28) in order to move them for re-arrangement purposes. Each of two segments (28) situated at opposite ends of the series comprises a shoe-holder body (48) which supports a respective shoe (50) by means of inclined guides. Each shoe-holder body (48) carries a respective slide (56) having a driving portion (60) and each shoe (50) has a driven portion (64). These driving and driven portions have facing cooperating pressure and sliding faces (62, 68) arranged in a manner such that a movement of the slide (56) towards the centre of the press is converted into an oblique movement of the respective shoe (50) such that is is released from a lateral channel-shaped bend already formed in a metal sheet, without sliding on the sheet. Each carriage (42) comprises an entraining member (44) and each slide (56) comprises an entrained member (58) which can be engaged by the entraining member (44) in order to move the slide (56) selectively towards the centre of the press. The two carriages (42) are movable simultaneously in opposite directions upon command in order to simultaneously bring about the aforementioned movements of the shoes (50), by means of the slides (56), in directions such as to release them from the respective lateral bends. The shoes (50) have respective resilient means for biasing them in directions such as to return each shoe (50) to a working position to which it is moved away from the centre of the press and from the movable blank-holder.
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