| 摘要 |
Apparatus for trimming perfect bound books is disclosed including a clamping assembly and a shearing assembly, preferably powered by electric motors. The clamping assembly includes a fixed anvil and a clamp member movable along a clamp track toward and away from the anvil. The shear assembly includes a shear blade movable along a shear track toward and away from the anvil. Load members are mounted on the clamp track and on the shear track. The clamp assembly and the shear assembly each has an electric motor driving a linear actuator (e.g., a drive screw) which is operatively coupled to its respective load member. A spring or a pair of springs is interposed between the clamp load member and the clamp member and another spring or a pair of springs is interposed between the shear blade and the shear load member. Thus, as the clamp member engages the book and as the shear blade shears through the book and engages the anvil, further movement of the clamp member and the shear blade is prevented. Continued operation of the motors causes these springs to compress and to thus result in differential movement (lost motion) between the clamp member and the clamp load member and between the shear blade and the shear load member. Operation of the motors is terminated upon this differential motion of a predetermined magnitude being sensed. |
