Abstract: Two arms carry two pawls each. One pawl of each arm engages one ratchet wheel and, alternately, the other pawl of each arm engages another ratchet wheel when the arms are moved at the end of the travel of a ribbon. The ratchet wheels carry ribbon spools. One arm carries push pawls. The other carries pull pawls. The push pawls act as no-backs, but they also drive the ratchet wheels. Each ratchet wheel is thus positively driven more or less continuously when it is driven. The ratchet wheels are driven alternately. An over-center transfer mechanism places a desired pair of pawls in position for ratchet wheel engagement and the other pair for disengagement at each end of the ribbon travel.

Abstract: A plastic laminate including a wedge having sides with a large radius and one or two grooved plates, flat when unstressed, and stressed when clamped to the wedge to conform to the radii thereof. The grooves then are three-dimensional and easily guide the print wires of a mosaic printer. Another advantage is achieved in that both wedge and plates can be molded with little or no difficulty in that the wedge mold surfaces are simple to machine, and the plates are initially flat and thus easy to mold. Close solenoid spacing is also made possible.

Abstract: A plastic laminate including a wedge having sides with a large radius and one or two grooved plates, flat when unstressed, and stressed when clamped to the wedge to conform to the radii thereof. The grooves then are three-dimensional and easily guide the print wires of a mosaic printer. Another advantage is achieved in that both wedge and plates can be molded with little or no difficulty in that the wedge mold surfaces are simple to machine, and the plates are initially flat and thus easy to mold. Close solenoid spacing is also made possible.