Typewriter carriage jam precluding and action jam release mechanisms

Abstract

A typewriter is provided with carriage control mechanisms such that more than one carriage control function can be initiated at one time. The arrangement of carriage function controls permit a dominant carriage movement to prevail, and less dominant carriage movement function controls will either give way or, in case of tabulation, give way and await completion of the dominant function while yet remaining in active position to arrest tabulating movement. No interlocking of carriage functions is necessary. More particularly, if a dominant carriage return is initiated, carriage return movement of the carriage will cause a backspace pawl, controlled by initiation of a backspace function, either immediately before or after carriage return movement begins, to move out of engagement from the escapement rack. If either a carriage or a backspace function is in progress, i.e., the carriage is moving to effect a carriage return or backspace, a tabulation function can still be initiated. If however, a set tab stop on the carriage, during movement of the carriage in return or backspace direction, encounters the tabular stop blade placed and latched in readiness to arrest a set tab stop during tabulation movement, it will cause the tab blade to be rocked out of the way yet remain latched whereby, on completion of carriage return movement, tabulation movement will begin and the first set tab stop encountered will be arrested by the positioned tab blade to terminate tabulating movement. Also provided is a tab set blade which, if operated during any carriage movement as would jam the carriage, will give way on encounter with set tab stops. Other features of the invention reside in a novel carriage construction, power roll construction, and power roll jam release controls.