Ribbon lifting mechanism for selectively placing a printing ribbon and a correction ribbon at a printing position of a typewriter

A ribbon lifting mechanism for a typewriter comprising:

• a frame;
• a holder supported rotatably on said frame for holding a printing ribbon and a correction tape;
• a first means for normally urging said holder toward a predetermined direction;
• a ribbon lifting cam having a plurality of cam sections formed thereon, said cam sections allowing the holder to turn so as to selectively assume an operative state where the printing ribbon is located at a printing position, an operative state where the correction tape is located at said printing position and an inoperative state where both the printing ribbon and the correction tape are located out of the printing position;
• a first cam follower connected to said holder and controlled by said cam sections;
• driving means for rotating the ribbon lifting cam in both normal and reverse directions in response to actuation of a key such as a letter key or the like;
• a movable stoper member engageable with and disengageable from the holder, said stopper member and a means for restricting an extent of turning movement serving to restrict an extent of turning movement of the holder within a predetermined range of movement when said stopper member is engaged with the holder;
• and
• means for displacing the stopper member to selectively assume the engagement position where the stopper member is engaged with the holder and the disengagement position where the stopper is disengaged from the holder when the ribbon lifting cam is rotated;
• the means for displacing the stopper member comprising a support shaft for supporting the stopper member in such a manner as to turn thereabout and move in the axial direction, second urging means for normally turning the stopper member in a predetermined direction, a limiting member for limiting turning movement of the stopper member within a predetermined extent of turning movement, third urging means for thrusting the stopper member toward the ribbon lifting cam in the axial direction of the support shaft and a projection disposed on the ribbon lifting cam to come in engagement with the stopper member.

A ribbon lifting mechanism for a typewriter essentially comprising;

• a frame;
• a holder supported rotatably on said frame for holding a printinq ribbon and a correction tape and serving to allow said printing ribbon and said correction tape to selectively assume a printing position;
• a first means for normally urging said holder toward the printing position;
• a ribbon lifting cam having a plurality of cam sections formed on the one face thereof, said cam sections comprising a first cam section for allowing the printing ribbon to assume the printing position by turning movement of the holder, a second cam section formed in continuation from said first cam section so as to allow the correction tape to assume the printing position and a relieving section formed in continuation from the first cam section, said relieving section extending in parallel with said second cam section;
• driving means for rotating the ribbon lifting cam in both normal and reverse direction;
• a single cam follower connected to the holder to be moved by following the relative rotational movement of the ribbon lifting cam;
• a stopper member for holding the holder so as to allow the printing ribbon to be located at the printing position by introducing into the relieving section the cam follower which is actuated in accordance with the first cam section by rotation of the ribbon lifting cam in the normal direction during normal printing operation, and
• a second cam follower disposed on the stopper member and
• a groove-shaped means for displacing said stopper member for engaging said second cam follower, said displacing means being disposing on th eother face of the ribbon lifting cam in order to assure that the stopper member is released from the holding state of the holder during a corrective print operation so that the single cam follower which is actuated in accordance with the first cam section is caused to move in accordance with the second cam section and thereby the correction tape is located at the printing position and said stopper member including an annular third cam section for guiding relative movement of the second cam follower during printing operation as well as during non-printing operation, a arch-shaped fourth cam section formed co-axial relative to said third cam section to guide relative movement of the second cam follower during a corrective printing operation and two introduction cam grooves for establishing a connection between the third and fourth cam sections to guide relative movement of the second cam follower during a corrective printing operation.

A ribbon lifting mechanism for a typewriter essentially comprising;

• a frame;
• a holder supported rotatably on said frame, for holding a printing ribbon and a correction tape and serving to allow said printing ribbon and said correction tape to selectively assume a printing position;
• a first means for normally urging said holder toward the printing position;
• a ribbon lifting cam having a plurality of cam sections formed on the one face thereof, said plurality of cam sections comprising a first cam section for allowing the printing ribbon to assume the printing position by turning movement of the holder, a second cam section formed in continuation from said first cam section so as to allow the correction tape to assume the printing position and a relieving section formed in continuation from the first cam section, said relieving section extending in parallel with said second cam section;
• driving means for rotating the ribbon lifting cam in both a normal and a reverse direction;
• a single cam follower connected to the holder to be moved by following the relative rotational movement of the ribbon lifting cam;
• a stopper member for holding the holder so as to allow the printing ribbon to be located at the printing position by introducing into the relieving section the single cam follower which is actuated in accordance with the first section by rotation of the ribbon lifing cam in the normal direction during normal printing operation;
• and
• means for displacing said stopper member, said displacing means being disposed on the other face of the ribbon lifting cam in order to assure that the stopper member is released from the holding state of the holder during a corrective printing operation by introducing the cam follower into the relieving section by rotation of the ribbon lifting cam in the normal direction in the same manner as during the normal printing operation and thereafter rotating the ribbon lifting cam in the reverse direction by a predetermined angle, said means for displacing the stopper member comprising a support shaft for supporting the stopper member in such a manner as to turn thereabout and move in the axial direction, second urging means for normally turning the stopper memeber in a predetermined direction, a limiting member for limiting turning movement of the stopper member within a predetermined extent of turing movement, third urging means for thrusting the stopper member toward the ribbon lifting cam in the axial direction of the support shaft and a projection disposed on the ribbon lifting cam to come into engagement with the stopper memeber.