| 摘要 |
The invention relates to apparatus for incorporation in new typewriters or for attachment to existing typewriters for signalling a preset line, paragraph, or page length. The device attaches to the platen and platen support frame and permits the operator to index, from a starting or home position, the number of lines or amount of platen rotation desired. As typing proceeds and the platen rotates, relative motion is established between a bell ringer structure and a bell so that upon reaching the indexed position, the signal is sounded. Typing may be continued without damaging the device through the provision of a clutch or slipping mechanism. The device can be easily reset through the provision of an operator knob for disengaging the drive from the platen to permit a return spring, which has been tensioned by platen movement, to return the mechanism to home position.
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