Electrical stenographic machine

摘要

A stenographic machine having electrically powered paper advance and permitting control of key stroke length independent of the paper feed length. The print hammers are mechanically actuated by depression of the associated keys, as in a conventional mechanical stenographic machine. Operation of one or more of the keys actuates an optical switch to trigger a monostable multivibrator, the output of which energizes an actuator to rotate the platen, advancing the paper. The rest position of the keys can be controlled to control the key stroke length, without affecting the paper feed length. The paper advance is initiated on the return stroke of the keys, and so each printed word is visible to the operator immediately after the stroke for that word. In one embodiment the multivibrator energizes a solenoid to rotate the platen, while in a second embodiment the multivibrator energizes an electric motor. If desired, the duration of the multivibrator output pulse can be controlled to control the extent of movement of the solenoid plunger or of the electric motor and thus to control the paper advance length.