Line spacing mechanism for printing machine.

摘要

The line spacing mechanism for a typewriter comprises an electric motor (19) which is operable to rotate selectively in either direction. A worm (16) on the shaft (26) of the motor meshes with a helicoidally toothed wheel (14) to cause a platen roller (12) to rotate in the clockwise direction or the anticlockwise direction. The motor is support pivotally by trunions (42) and urged by a spring (52) to eliminate radial play between the worm and toothed wheel. Another spring (67), lever (62) and ball (64) apply thrust to the motor shaft to take up axial play in its bearing (21, 22), i.e. between the worm and the motor.