| 摘要 |
<p>DRIVE MECHANISM FOR COMPUTER FORM FEEDER APPARATUS A mechanism for driving a computer form web along a predetermined path includes a ratchet wheel having two sets Or oppositely facing teeth, mounted on a support shaft for rotation. The wheel is driven in both clockwise and counter-clockwise directions. A drive gear in meshing engagement with a plurality of gears for driving the sprocket mechanism transporting the computer form web is also mounted on the support shaft for rotation. The gear is joined to a coupling plate also mounted on the support shaft for rotation thereon. The coupling plate includes first and second pawls which extend therefrom for cooperative engagement with the ratchet teeth sets, respectively. Pawl actuator arms also mounted on the coupling plate are movable to first and second positions and when in a first position engage the pawls to maintain the latter out of engagement with respective ratchet teeth sets. Pawl actuator arm engaging levers are mounted adjacent the pawl actuator arms and are movable to first and second positions. When in the first position the levers engage the pawl actuator arms to maintain them in the first position. Movement of the lever arms to the second position permits the pawls to be moved toward the ratchet wheel. Depending upon the direction of rotation of the ratchet wheel, one or the other of the pawls engages a tooth of a corresponding ratchet teeth set, thereby coupling the rotating ratchet wheel to the drive gear. Returning the levers to their first position permits engagement therewith by the actuator arms revolving on the rotating coupling plate, to urge the actuator arms to the first position, thereby moving the pawls away from the ratchet teeth for disengagement of the engaged pawl and ratchet tooth. This action discontinues the rotation of the gear member and stops the driving of the computer form web. Control of movement of the lever arms in turn control the number of revolutions of the drive gear and thus the extent of movement of the computer web along its path. A manually operated gear selector for providing a change in gear ratios controls the length of movement of the computer web for each revolution of the drive gear. Continual rotation of the drive gear can be achieved by maintaining the lever arms in the second position.</p> |
