| 摘要 |
To bend sheet metal through a wide angle into an acute angle, this bending brake has a foundation carrying a stationary workpiece-clamping structure including multiple J-shaped stationary workpiece-clamping jaw supports disposed in spaced parallel relationship and carrying an elongated stationary workpiece-clamping jaw. The upper portion of each such support terminates in a U-shaped cam thrust abutment engaged by an eccentric movable-jaw-operating cam operatively secured to a common composite cam shaft journaled in multiple movable workpiece-clamping jaw arms with downwardly-curved rearward end portions pivotally mounted at their rearward ends upon pivot bolts carried by the upwardly-curved rearward end portions of the stationary supports. Secured to and extending between the forward ends of these arms is a movable workpiece-clamping jaw of wedge-shaped cross-section and having a forward bending edge disposed immediately above the stationary workpiece-clamping jaw and also immediately above a so-called piano hinge which pivotally supports an elongated workpiece-bending structure movable upward and downward by one or more handles. Operatively connected to the composite cam shaft adjacent the stationary supports are the inner ends of handle arms disposed in spaced parallel relationship and connected at their outer ends to a common cam-operating handle bar which, when swung forward and rearward, rotates the cams against their respective thrust abutments to move the clamping arms upward and downward so as to move the movable clamping jaw toward and away from the stationary workpiece-clamping jaw.
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