| 摘要 |
<p>A counter mechanism for a postage meter includes a number of sections each having a number wheel (14) representing the respective order of accounted value, transfer mechanisms in the form of Geneva gears connecting the number wheels (14) to provide carry-over movements between adjacent sections. A ratchet mechanism is provided in the number wheel (14) to allow rotation of the number drum (16) as a result of an account input from the postage meter, even when a carry movement gear (18) of the number wheel (14) is locked by the Geneva gear. The ratchet mechanism includes an internally-profiled surface on one part (16) having ratchet steps (70) separated by portions (76) of relatively low gradient. Projections (74) are provided on a central member (72) of another part (18), the projections extending substantially tangential to the internally-profiled surface so as to engage in the ratchet steps (70) in the event of attempted rotation in one direction and to stop such rotation. Rotation in the other direction can take place.</p><p>The counter mechanism may also include thumbwheels for resetting the lower order number wheels (14), the thumbwheels including similar ratchet mechanisms. </p> |
