| 摘要 |
The hole punching machine comprises a revolving drum with a series of slits corresponding to the number of lines of punched holes required. Fixed to the central drive shaft of the drum are electromagnets (3, 4) having hammer-shaped pole-pieces (5) with curved outer edges (6). Immediately under each pole-piece are swivel armatures positioned in slots in the drum (18). Energising the magnet draws the arm inwards, causing its striker head to protrude through the slit (11) and at each revolution, to engage a cam face (13) below the drum. the cam has a second notch (15) which depresses the spring-loaded punch pin (25) forcing it downwards trough the guide (22). |
