Print ribbon driving mechanism

Mechanism for driving a pair of spools having a print ribbon wound thereon and extending therebetween and including:

• a pair of rotatably mounted, fixedly positioned spindles each adapted to carry a print ribbon spool,
• a reciprocatively mounted support carrying a printhead which is movable between said spindles, toward one of said pair of spindles and away from the other of said spindles,
• a switching bail swingably mounted on said reciprocatively mounted support and having two pawl portions on opposite ends formed as an integral part of said bail, one of which is adapted to contact and rotate one of said spindles during the final portion of reciprocative motion of said support toward said one spindle in the first principal swung position of the switching bail, and the other of which is adapted to contact and rotate the other of said spindles during the final portion of reciprocative motion of said support toward such other spindle in the second principal swung position of the switching bail,
• a trigger lever swingably mounted on each of said spindles and adapted to swing into an operative position as the last convolution of ribbon is unwound from the spool mounted on this spindle, and
• a pair of camming surfaces on opposite ends of said switching bail for engaing the associated one of said trigger levers in the said operative position as said support moves toward the spindle carrying said one trigger lever so that the switching bail is swung from one principal swung position to the other principal swung position to be effective to drivingly rotate said spindle carrying said one trigger lever on successive reciprocative movements of said support toward this spindle for thereby causing the spool on such spindle to wind the print ribbon thereon;
• said switching bail in one principal swung position engaging one spindle with said pawl portion at one end of a reciprocative stroke and having the camming surface at the opposite end of the bail positioned to contact the trigger lever of the other spindle, when in said operative position, at the end of the opposite reciprocative stroke to pivot said switching bail to the other of said principal swung positions, whereby during a reversing action said pawl portions are disengaged from said spindles.