Ribbon reversal mechanism for an office machine

Claim 2

A mechanism for reversing the movement of an inked ribbon in a printing machine, the mechanism comprising: first and second rotors each for effecting the rotation of one of two ribbon spools on which the ribbon is mounted; a driving element for alternately imparting a driving force to one of said first and second rotors; and reversing means for alternately selectively coupling said driving element to one of said first and second rotors to effect the reversal of the movement of the ribbon, said reversing means comprising a reversing member shiftable between a first position wherein said driving element is coupled to said first rotor and a second position wherein said driving element is coupled to said second rotor, detent means resiliently coupling said reversing member to said driving element for rotating said reversing member by said driving element when said reversing member is loaded up to or below a predetermined torque and for interrupting said coupling between said reversing member and said driving element when said reversing member is loaded more than said predetermined torque causing a reciprocal rotation between said driving element and said reversing member, means for shifting said reversing member from one to the other of said first and second positions in response to said reciprocal rotation; and ribbon sensing means for sensing that a predetermined amount of ribbon is on one ribbon spool indicating that reversal is required and including means for effecting application of said predetermined torque on said reversing member when the reversal is required to shift said reversing member whereby said driving element is coupled to the other rotor and reversal is effected.

Claim 3

A mechanism according to claim 1, wherein the detent means include a click-stop mechanism for causing the reversing member to be shiftable with a snap-action between the first and second positions and wherein the click-stop mechanism includes a cam structure which biases the reversing member in the direction of the first position in alternate stable settings of the click-stop mechanism and biases the reversing member in the direction of the second position in the intervening stable settings of the click-stop mechanism.

Claim 4

A mechanism according to claim 2, wherein the first and second positions of the reversing member are defined by two respective stops against which the reversing member is biased by the action of the cam structure.

Claim 5

A mechanism according to claim 1, wherein the reversing means includes a drive train including said reversing member for coupling rotary movement from the driving element to the first or second rotor, depending upon the position of the reversing member.

Claim 6

A mechanism according to claim 3, wherein the reversing member and driving element are two concentric parts of which one is a sleeve having the cam structure on its inner periphery and the other is a cylindrical body rotatable within the sleeve subject to the constraint of the click-stop mechanism, the concentric parts being axially shiftable relative to one another under the action of the cam structure.

Claim 7

A mechanism according to claim 5, wherein each rotor includes a bevel gear and one of the concentric parts which constitutes the reversing member has bevel gears on its two ends which engage with either of the bevel gears of the rotors depending upon the position of the reversing member, and the other of the concentric parts is axially fixed.

Claim 8

A mechanism according to claim 1, wherein the ribbon sensing means comprises a pair of sensing elements each biased against the ribbon on one of the two ribbon spools.

Claim 9

A mechanism according to claim 7, wherein the means for effecting the predetermined torque includes means mounting each sensing element to arrest the rotation of the driven rotor when said each sensing element respectively senses that the ribbon spool acting as feed spool has said predetermined amount of ribbon thereon.

Claim 10

A mechanism according to claim 8, wherein said means for effecting the predetermined torque includes a stop on each rotor and wherein each sensing element, when said each sensing element respectively senses that a ribbon reversal is required, moves into the path of the stop on the rotor which is driven from the driving element to arrest said driven rotor and therefore said reversing member.

Claim 11

A mechanism for reversing the movement of an inked ribbon in an office printing machine or the like, the mechanism comprising: first and second rotors each for effecting the rotation of one of two ribbon spools on which the ribbon is mounted; a driving element for alternately imparting a driving force to one of said first and second rotors; and reversing means for alternately selectively coupling said driving element to one of said first and second rotors to effect the reversal of the movement of the ribbon, said reversing means comprising a reversing member shiftable between a first position wherein said driving element is coupled to said first rotor and a second position wherein said driving element is coupled to said second rotor, detent means for resiliently coupling said reversing member to said driving element for rotational movement therewith while maintaining said reversing member in one of said two positions and effecting the shifting thereof to the other of said two positions in response to the application of a predetermined torque, and ribbon sensing means for sensing that a predetermined amount of ribbon is on one ribbon spool indicating that reversal is required and including means for effecting application of said predetermined torque when the reversal is required to shift said reversing member whereby said driving element is coupled to the other rotor and reversal is effected, wherein said driving element is a sleeve axially fixed, said reversing member is a cylindrical body rotatable concentrically and shiftable axially within said sleeve, wherein said detent means includes a click-stop mechanism for causing said cylindrical body to be shiftable with a snap-action between said first and second positions, said click-stop mechanism including a cam structure on the inner periphery of said sleeve which axially biases said cylindrical body in the direction of said first position in alternate stable settings of said click-stop mechanism and biases said cylindrical body in the direction of said second position in the intervening stable settings of said click-stop mechanism wherein said first and second positions of said cylindrical body are defined by two respective stops against which said cylindrical body is biased by the action of said cam structure, and wherein said cylindrical body is rotatable within said sleeve subject to the constraint of said click-stop mechanism and said cylindrical body is axially shiftable relative to said sleeve under the action of said cam structure.

Claim 12

A mechanism for reversing the movement of an inked ribbon in an office printing machine or the like, the mechanism comprising: first and second rotors each for effecting the rotation of one of two ribbon spools on which the ribbon is mounted; a driving element for alternately imparting a driving force to one of said first and second rotors; and reversing means for alternately selectively coupling said driving element to one of said first and second rotors to effect the reversal of the movement of the ribbon, said reversing means comprising a reversing member shiftable between a first position wherein said driving element is coupled to said first rotor and a second position wherein said driving element is coupled to said second rotor, detent means for resiliently coupling said reversing member to said driving element for rotational movement therewith while maintaining said reversing member in one of said two positions and effecting the shifting thereof to the other of said two positions in response to the application of a predetermined torque, and ribbon sensing means for sensing that a predetermined amount of ribbon is on one ribbon spool indicating that reversal is required and including means for effecting application of said predetermined torque when the reversal is required to shift said reversing member whereby said driving element is coupled to the other rotor and reversal is effected, wherein said driving element is a sleeve axially fixed, said reversing member is a cylindrical body rotatable concentrically and shiftable axially within said sleeve, wherein said detent means includes a click-stop mechanism for causing said cylindrical body to be shiftable with a snap-action between said first and second positions, said click-stop mechanism including a cam structure on the inner periphery of said sleeve which axially biases said cylindrical body in the direction of said first position in alternate stable settings of said click-stop mechanism and biases said cylindrical body in the direction of said second position in the intervening stable settings of said click-stop mechanism wherein said first and second positions of said cylindrical body are defined by two respective stops against which said cylindrical body is biased by the action of said cam structure, and wherein said cylindrical body is rotatable within said sleeve subject to the constraint of said click-stop mechanism and said cylindrical body is axially shiftable relative to said sleeve under the action of said cam structure.

Claim 13

A mechanism for reversing the movement of an inked ribbon in an office printing machine or the like, the mechanism comprising: first and second rotors each for effecting the rotation of one of two ribbon spools on which the ribbon is mounted; a driving element for alternately imparting a driving force to one of said first and second rotors; and reversing means for alternately selectively coupling said driving element to one of said first and second rotors to effect the reversal of the movement of the ribbon, said reversing means comprising a reversing member shiftable between a first position wherein said driving element is coupled to said first rotor and a second position wherein said driving element is coupled to said second rotor, detent means for resiliently coupling said reversing member to said driving element for rotational movement therewith while maintaining said reversing member in one of said two positions and effecting the shifting thereof to the other of said two positions in response to the application of a predetermined torque, and ribbon sensing means for sensing that a predetermined amount of ribbon is on one ribbon spool indicating that reversal is required and including means for effecting application of said predetermined torque when the reversal is required to shift said reversing member whereby said driving element is coupled to the other rotor and reversal is effected, wherein said detent means includes a click-stop mechanism for causing the reversing member to be shiftable with a snap-action between said first and second positions, said click-stop mechanism having a cam structure which biases said reversing member in the direction of said first position in alternate stable settings of said click-stop mechanism and biases said reversing member in the direction of said second position in the intervening stable settings of said click-stop mechanism, wherein said first and second positions of said reversing member are defined by two respective stops against which said reversing member is biased by the action of said cam structure, wherein said reversing member and said driving element are two concentric parts of which one is a sleeve having said cam structure on its inner periphery and the other is a cylindrical body rotatable within said sleeve subject to the constraint of said click-stop mechanism, said concentric parts being axially shiftable relative to one another under the action of said cam structure, and wherein said cam structure comprises click-stop recesses in said click-stop mechanism around an annular region of an inner periphery of said sleeve, said recesses having bottoms inclined axially of said sleeve in alternate directions around said annular region, and said recesses being engaged by a resiliently acting detent member of said cylindrical body so as both to provide the snap action and the biasing towards said two positions by engagement of said detent member with said inclined bottoms of said recesses.

Claim 14

A mechanism for reversing the movement of an inked ribbon in an office printing machine or the like, the mechanism comprising: first and second rotors each for effecting the rotation of one of two ribbon spools on which the ribbon is mounted; a driving element for alternately imparting a driving force to one of said first and second rotors; and reversing means for alternately selectively coupling said driving element to one of said first and second rotors to effect the reversal of the movement of the ribbon, said reversing means comprising a reversing member shiftable between a first position wherein said driving element is coupled to said first rotor and a second position wherein said driving element is coupled to said second rotor, detent means for resiliently coupling said reversing member to said driving element for rotational movement therewith while maintaining said reversing member in one of said two positions and effecting the shifting thereof to the other of said two positions in response to the application of a predetermined torque, and ribbon sensing means for sensing that a predetermined amount of ribbon is on one ribbon spool indicating that reversal is required and including means for effecting application of said predetermined torque when the reversal is required to shift said reversing member whereby said driving element is coupled to the other rotor and reversal is effected, wherein said detent means includes a click-stop mechanism for causing the reversing member to be shiftable with a snap-action between said first and second positions, said click-stop mechanism having a cam structure which biases said reversing member in the direction of said first position in alternate stable settings of said click-stop mechanism and biases said reversing member in the direction of said second position in the intervening stable settings of said click-stop mechanism, wherein said first and second positions of said reversing member are defined by two respective stops against which said reversing member is biased by the action of said cam structure, wherein said reversing member and said driving element are two concentric parts of which one is a sleeve having said cam structure on its inner periphery and the other is a cylindrical body rotatable within said sleeve subject to the constraint of said click-stop mechanism, said concentric parts being axially shiftable relative to one another under the action of said cam structure, and wherein said cam structure comprises click-stop recesses in said click-stop mechanism around an annular region of an inner periphery of said sleeve, said recesses having bottoms inclined axially of said sleeve in alternate directions around said annular region, and said recesses being engaged by a resiliently acting detent member of said cylindrical body so as both to provide the snap action and the biasing towards said two positions by engagement of said detent member with said inclined bottoms of said recesses.

Claim 15

A mechanism according to claim 11, wherein the recesses comprise two sets of grooves having ends interdigitated in the annular region, the grooves of one set extending in one axial direction away from the annular region, the grooves of the other set extending in the other axial direction away from the annular region, and the interdigitated ends tapering out to form the inclined bottoms.

Claim 16

A mechanism according to claim 17, wherein the detent means further comprises a plunger protruding from a hole in the cylindrical body and a spring housed in the cylindrical body and biasing the plunger into the protruding position.

Claim 17

A mechanism according to claim 11, wherein the detent means comprises two plungers protruding from opposite ends of a diametral hole through the cylindrical body and a spring compressed between the plungers.

Claim 18

A mechanism for reversing the movement of an inked ribbon in an office printing machine or the like, the mechanism comprising: first and second rotors each for effecting the rotation of one of two ribbon spools on which the ribbon is mounted; a driving element for alternately imparting a driving force to one of said first and second rotors; and reversing means for alternately selectively coupling said driving element to one of said first and second rotors to effect the reversal of the movement of the ribbon, said reversing means comprising a reversing member shiftable between a first position wherein said driving element is coupled to said first rotor and a second position wherein said driving element is coupled to said second rotor, detent means for resiliently coupling said reversing member to said driving element for rotational movement therewith while maintaining said reversing member in one of said two positions and effecting the shifting thereof to the other of said two positions in response to the application of a predetermined torque, and ribbon sensing means for sensing that a predetermined amount of ribbon is on one ribbon spool indicating that reversal is required and including means for effecting application of said predetermined torque when the reversal is required to shift said reversing member whereby said driving element is coupled to the other rotor and reversal is effected, wherein said ribbon sensing means comprises a pair of sensing elements each biased against the ribbon on one of said two ribbon spools, and said means for effecting the application of said predetermined torque include a stop on each rotor and means mounting each sensing element such that each sensing element moves into the path of said stop on the rotor which is being driven from said driving element to arrest the rotation of said driven rotor when said each sensing element respectively senses that the ribbon spool acting as feed spool has said predetermined amount of ribbon thereon and that a ribbon reversal is required; and wherein each said sensing element comprises two levers fixed together, one of said levers being biased against the ribbon on the ribbon spool on one rotor and the other of said two levers moving into the path of said stop on the other rotor when the ribbon spool on said one rotor has the predetermined amount of ribbon thereon.

Claim 19

A mechanism for reversing the movement of an inked ribbon in an office printing machine or the like, the mechanism comprising: first and second rotors each for effecting the rotation of one of two ribbon spools on which the ribbon is mounted; a driving element for alternately imparting a driving force to one of said first and second rotors; and reversing means for alternately selectively coupling said driving element to one of said first and second rotors to effect the reversal of the movement of the ribbon, said reversing means comprising a reversing member shiftable between a first position wherein said driving element is coupled to said first rotor and a second position wherein said driving element is coupled to said second rotor, detent means for resiliently coupling said reversing member to said driving element for rotational movement therewith while maintaining said reversing member in one of said two positions and effecting the shifting thereof to the other of said two positions in response to the application of a predetermined torque, and ribbon sensing means for sensing that a predetermined amount of ribbon is on one ribbon spool indicating that reversal is required and including means for effecting application of said predetermined torque when the reversal is required to shift said reversing member whereby said driving element is coupled to the other rotor and reversal is effected, wherein said ribbon sensing means comprises a pair of sensing elements each biased against the ribbon on one of said two ribbon spools, and said means for effecting the application of said predetermined torque include a stop on each rotor and means mounting each sensing element such that each sensing element moves into the path of said stop on the rotor which is being driven from said driving element to arrest the rotation of said driven rotor when said each sensing element respectively senses that the ribbon spool acting as feed spool has said predetermined amount of ribbon thereon and that a ribbon reversal is required; and wherein each said sensing element comprises two levers fixed together, one of said levers being biased against the ribbon on the ribbon spool on one rotor and the other of said two levers moving into the path of said stop on the other rotor when the ribbon spool on said one rotor has the predetermined amount of ribbon thereon.

Claim 20

A mechanism for reversing the movement of an inked ribbon in an office printing machine or the like, the mechanism comprising: first and second rotors each for effecting the rotation of one of two ribbon spools on which the ribbon is mounted; a driving element for alternately imparting a driving force to one of said first and second rotors; and reversing means for alternatively selectively coupling said driving element to one of said first and second rotors to effect the reversal of the movement of the ribbon, said reversing means comprising a reversing member shiftable between a first position wherein said driving element is coupled to said first rotor and a second position wherein said driving element is coupled to said second rotor, detent means for resiliently coupling said reversing member to said driving element for rotational movement therewith while maintaining said reversing member in one of said two positions and effecting the shifting thereof to the other of said two positions in response to the application of a predetermined torque, and ribbon sensing means for sensing that a predetermined amount of ribbon is on one ribbon spool indicating that reversal is required and including means for effecting application of said predetermined torque when the reversal is required to shift said reversing member whereby said driving element is coupled to the other rotor and reversal is effected, and further comprising means for frictionally restraining the rotation of each rotor including a spring, a plunger for each rotor engageable in a hole in a ribbon spool located on said rotor and a fixed plate and wherein said plunger is biased by the spring against a surface of said fixed plate.

Claim 21

A mechanism for reversing the movement of an inked ribbon in an office printing machine or the like, the mechanism comprising: first and second rotors each for effecting the rotation of one of two ribbon spools on which the ribbon is mounted; a driving element for alternately imparting a driving force to one of said first and second rotors; and reversing means for alternatively selectively coupling said driving element to one of said first and second rotors to effect the reversal of the movement of the ribbon, said reversing means comprising a reversing member shiftable between a first position wherein said driving element is coupled to said first rotor and a second position wherein said driving element is coupled to said second rotor, detent means for resiliently coupling said reversing member to said driving element for rotational movement therewith while maintaining said reversing member in one of said two positions and effecting the shifting thereof to the other of said two positions in response to the application of a predetermined torque, and ribbon sensing means for sensing that a predetermined amount of ribbon is on one ribbon spool indicating that reversal is required and including means for effecting application of said predetermined torque when the reversal is required to shift said reversing member whereby said driving element is coupled to the other rotor and reversal is effected, and further comprising means for frictionally restraining the rotation of each rotor including a spring, a plunger for each rotor engageable in a hole in a ribbon spool located on said rotor and a fixed plate and wherein said plunger is biased by the spring against a surface of said fixed plate.

Claim 22

A mechanism for reversing the movement of an inked ribbon in a printing machine comprising: two spools carrying the ribbon; a pair of sensing elements for sensing the amount of the ribbon on said two spools and indicating that a ribbon reversal is required; a driving element; a rotatable reversing member shiftable between a first and a second position in response to the indication of said sensing elements to drive alternatively said two spools to move the ribbon in opposite directions; means coupling said driving element to said reversing member for the rotation thereof, said coupling means including means for maintaining said reversing member in one of said first or said second positions coupled with said driving element to be rotated thereby when said reversing member is loaded up to or below a predetermined torque to drive one of said two spools, means for causing each of said sensing elements to apply more than said predetermined torque to said reversing member when the ribbon reversal is required thereby releasing said coupling means and causing a reciprocal rotation of said driving element with respect to said reversing member, said coupling means further including means for shifting said reversing member to the other of said first or said second positions in response to said reciprocal rotation thereby coupling said reversing member to the other of said two spools to effect the reversal of movement of said ribbon.

Claim 23

A mechanism for reversing the movement of an inked ribbon in a printing machine comprising: two spools carrying the ribbon; a pair of sensing elements for sensing the amount of the ribbon on said two spools and indicating that a ribbon reversal is required; a driving element; a rotatable reversing member shiftable between a first and a second position in response to the indication of said sensing elements to drive alternatively said two spools to move the ribbon in opposite directions; means coupling said driving element to said reversing member for the rotation thereof, said coupling means including means for maintaining said reversing member in one of said first or said second positions coupled with said driving element to be rotated thereby when said reversing member is loaded up to or below a predetermined torque to drive one of said two spools, means for causing each of said sensing elements to apply more than said predetermined torque to said reversing member when the ribbon reversal is required thereby releasing said coupling means and causing a reciprocal rotation of said driving element with respect to said reversing member, said coupling means further including means for shifting said reversing member to the other of said first or said second positions in response to said reciprocal rotation thereby coupling said reversing member to the other of said two spools to effect the reversal of movement of said ribbon.

Claim 24

A mechanism for reversing the movement of an inked ribbon in a printing machine comprising: first and second rotors for effecting the rotation of first and second spools respectively on which the ribbon is mounted; a rotatable driving element axially fixed out of engagement with said first and second rotors; an axially shiftable reversing member movable between a first position having a driving engagement with said first rotor and a second position having a driving engagement with said second rotor; releaseable detent means for providing a resilient coupling between said reversing member and said driving element when said reversing member is in said first and second positions to thereby effect rotation of said reversing member and said first and second rotors, means for releasing said detent means to interrupt said coupling when ribbon reversal is required; and said detent means further including means for shifting said reversing member between said first and second positions to effect ribbon reversal when said coupling is interrupted.

Claim 25

A mechanism for reversing the movement of an inked ribbon in a printing machine comprising: first and second rotors for effecting the rotation of first and second spools respectively on which the ribbon is mounted; a rotatable driving element axially fixed out of engagement with said first and second rotors; an axially shiftable reversing member movable between a first position having a driving engagement with said first rotor and a second position having a driving engagement with said second rotor; releaseable detent means for providing a resilient coupling between said reversing member and said driving element when said reversing member is in said first and second positions to thereby effect rotation of said reversing member and said first and second rotors, means for releasing said detent means to interrupt said coupling when ribbon reversal is required; and said detent means further including means for shifting said reversing member between said first and second positions to effect ribbon reversal when said coupling is interrupted.