Ink ribbon feeder
AssigneeStar Seimitsu Kabushiki Kaisha
InventorKatsumi Maeda
Life of this patent
Estimating the term…
Abstract
An ink ribbon feeder having a pair of rotatable ratchet wheels for driving ribbon spools. A control member rockable toward either ratchet wheel carries a ratchet wheel drive member movable on the control member for driving a respective one of the ratchet wheels to which the control member has been rocked. When ribbon from a spool has run out so that ribbon tension prevents further driving of a particular ratchet wheel, the control member rocks toward the other ratchet wheel to bring the ratchet wheel drive member into position to drive the other ratchet wheel and feed the ribbon in a reverse direction.
Claims4
An ink ribbon feeder for causing a reciprocating movement of an ink ribbon between a pair of spools;
- comprising
- a baseplate;
- a pair of ratchet wheels rotatably mounted on the baseplate for driving the spools;
- a control member located intermediate the pair of ratchet wheels and supported on the baseplate so as to be movable in a direction perpendicular to a line joining the axes of the pair of ratchet wheels and so as to permit one end thereof to be rockable toward either ratchet wheel;
- a ratchet wheel drive member carried by one end of the control member, the ratchet wheel drive member having one end which is disposed centrally in one end of the control member so as to be rockable and so as to be movable in a direction toward the other end of the control member, the other end of the ratchet wheel drive member selectively engaging with a tooth on a respective one of the ratchet wheels and being formed with an engaging portion which causes said one ratchet wheel to rotate when the control member rocks toward said one ratchet wheel;
- a resilient member having its one end connected to a central portion of the other end of the ratchet wheel drive member and its other end connected to a central portion of the other end of the control member, thereby urging the ratchet wheel drive member toward the other end of the control member;
- a switching lever having a pair of anti-reversing pawls on one end thereof which selectively engage a tooth on a respective one of the pair of ratchet wheels to prevent a reverse rotation of the engaged ratchet wheel, the switching lever being pivotally mounted on the baseplate intermediate its ends, one end of the switching lever carrying said one end of the control member so as to be movable in said perpendicular direction and so as to be rockable whenever the control member rocks in the same direction as the rocking motion of the control member;
- means on the other end of the switching lever for selectively urging said one end of the switching lever toward one of the ratchet wheels said urging means acting, whenever the center of said one end of the switching lever has rocked toward either ratchet wheel from a line which perpendicularly intersects with said first mentioned line at a point midway between the pair of ratchet wheels, to cause said one end of the switching lever to rock toward the ratchet wheel;
- a drive member for moving the control member in said perpendicular direction;
- means for driving the drive member to urge the control member in one direction, the engaging element of the ratchet wheel drive member being engaged with one of the ratchet wheels when the urging means urges the control member in said one direction;
- and wherein the other end of the ratchet wheel drive member is provided with a projection on its bottom surface, and the control member has a guide slot in which the projection on the ratchet wheel drive member bottom surface loosely fits, the guide slot including a rectilinear slot portion which guides the drive member for movement in said direction, and the guide slot including an arcuate slot portion having a central portion connected with one end of the rectilinear slot portion for guiding the drive member for rocking motion.
Dependencies are inferred from the claim text.