Arrangements relating to the printing ribbon in printing machines

Claim 1

IN A SYSTEM FOR MOVING AN INKED RIBBON IN A PRINTING MECHANISM, IN EITHER OF TWO OPPOSITE DIRECTIONS, OR WHERE NECESSARY IN ONLY ONE DIRECTION, THE COMBINATION COMPRISING A FIRST AND A SECOND DRIVING ROLLER, AN INKED RIBBON WHOSE TWO ENDS ARE EACH FIXED TO ONE OF THE SAID ROLLERS, DRIVING MEANS FOR DRIVING EACH ROLLER SEPARATELY IN ONE DIRECTION AND COMPRISING FOR EACH ROLLER AN ELECTRIC INDUCTION MOTRO MECHANICALLY COUPLED TO THE SAID ROLLER THROUGH AN ELECTROMAGNETIC CLUTCH, A SPEED-CHANGING DEVICE DISPOSE BETWEEN THE MOTOR FOR DRIVING THE FIRST ROLLER AND THE CLUTCH ASSOCIATED WITH THE SAID ROLLER FOR EFFECTING THE DRIVE OF THE SAID ROLLER AT ONE OF TWO DIFFERENT SPEEDS, IN DEPENDENCE UPON A PREVIOUS MANUAL POSITIONING OF THE SAID DEVICE, AND ALTERNATING-CURRENT SOURCE, A DIRECTCURRENT SOURCE, AND SWITCHING MEANS FOR CONTROLLING THE SUPPLY OF CURRENT TO THE MOTORS AND TO THE CLUTHES, THE SAID SWITCHING MEANS BEING CONTROLLED IN DEPENDENCE UPON THE MANUAL POSITIONING OF THE SPEED-CHANGING DEVICE IN SUCH MANNER THAT, WHEN THE SAID DEVICE IS BROUGHT INTO A FIRST POSITION, THE CLUTCH OF THE FIRST ROLLER IN CONNECTED TO THE DIRECT-CURRENT SOURCE FOR TRANSMITTING A MAXIMUM TORQUE, THE INDUCTOR OF THE MOTOR OF THE FIRST ROLLER IS CONNECTED TO THE ALTERNATING-CURRENT SOURCE FOR DRIVING THE SAID ROLLER AT HIGH SPEED THROUGH THE ASSOCIATED CLUTCH, THE CLUTCH OF THE SECOND ROLLER IS SUPPLIED WITH DIRECT CURRENT OF LOWER STRENGTH PERMITTING SLIPPING OF THE SAID CLUTCH, AND THE INDUCTOR OF THE SECOND ROLLER IS CONNECTED TO THE DIRECT-CURRENT SOURCE FOR CREATING A MAGNECTIC BRAKING FIELD ON THE ARMATURE OF THE SAID MOTOR AND ENSURING TENSIONING OF THE RIBBON, WHILE, WHEN THE SAID SPEED-CHANGING DEVICE IS BROUGHT TO A SECOND POSITION, THE CLUTCH OF THE FIRST ROLLER IS CONNECTED TO THE DIRECTCURRENT SOURCE FOR TRANSMITTING A MAXIMUM TORQUE, THE INDUCTOR OF THE MOTOR OF THE FIRST ROLLER IS CONNECTED TO THE ALTERNATING-CURRENT SOURCE FOR DRIVING THE SAID ROLLER AT REDUCED SPEED THROUGH THE ASSOCIATED CLUTCH, AND THE CLUTCH OF THE SECOND ROLLER IS CONNECTED TO THE DIRECTCURRENT SOURCE FOR PERMITTING MAXIMUM MECHANICAL COUPLING BETWEEN THE SECOND ROLLER AND THE MOTOR ASSOCIATED THEREWITH IN ORDER TO CREATE ON THE SECOND ROLLER DRIVEN BY THE RIBBON AN OPPOSED TORQUE WHICH ENSURES THE TENSIONING OF THE SAID RIBBON.