Including Plural Ratchet Wheels Patents (Class 400/331)
  • Patent number: 4285605
    Abstract: A mechanism which will function to allow the escapement of the carriage of a typewriter in one of two predetermined escapement pitches and be capable of backspace operation from a single backspace input for both pitches regardless of which escapement pitch is selected. Escapement ratchets for the two selected pitches are combined, together with a backspace ratchet. Each of the escapement ratchets are engageable by an escapement pawl and the engagement of a pawl with a particular ratchet will determine the pitch within which the escapement system will function. A backspace ratchet is combined with the escapement ratchets and fixedly attached thereto to provide the backspace drive. The backspace ratchet is selectably engageable by the backspace pawl for causing rotation in the opposite direction of that normally utilized for escapement.
    Type: Grant
    Filed: July 2, 1979
    Date of Patent: August 25, 1981
    Assignee: International Business Machines Corporation
    Inventors: Edward R. Lloyd, Raymond M. Marowski