Escapement mechanism and backspace mechanism for a moving paper carriage typewriter having dual pitch capability

摘要

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. All motion of the escapement ratchets or backspace ratchet is transmitted through a pinion mounted to the ratchet assembly and, in turn, is transmitted to the paper carriage rack.