Patent GB-278959-A (GB)
Title: Ribbon-reversing means for typewriters
IPC: B41J33/40
Filed: 1927-03-21
Abstract: 278,959. Triumph-Werke N³rnberg Akt.-Ces., and Kupfer, C. March 21, 1927. Ink-ribbon mechanism. - Automatic ribbonreversing mechanism comprises reversing-levers which are controlled by the ribbon and actuate suspension arms carrying a bar for reversing the drive, each reversing-lever being associated with a locking-lever adapted to lock the reversing- lever after the latter has been actuated by the ribbon and returned to normal position; the ribbon mechanism may be driven by the spring drum through a one-way clutch adapted to be automatically released if the ribbon mechanism jams. arrest of the carriage by the jamming of the ribbon mechanism being thereby prevented. In the mechanism shown in Figs. 1 and 4, the shafts 3, 4 of the spools 1, 2 have bevel-wheels 5, 6 co-operating alternately with bevel-wheels 8, 9 on driving-shaft 7, provided in the known manner with a hroad pinion 10 engaging a crownwheel 11 on the shaft 12 of the spring drum. The driving-shaft is moved longitudinally to reverse the feed by means of a bar 13 carried by rocking arms 16, 17, a lug 14 on the bar being arranged between adjustable collars 15 on the shaft. The arm 17 is formed with inclines 18 engaging a roller 19 on a yoke 20 pivoted on a spindle 21 and urged upwards by a spring 22. The shaft is retained by means of a spring-urged lever 25 which engages either of two grooves in a collar 29 on the shaft, the lever being pivoted on the spindle 21 and having a lug 24 engaging the yoke 20. Each spool is associated with a ribbon-guiding roller 31 carried by a reversing- lever consisting of a bent frame 30 mounted on a vertical pivot 35 and having a finger 30<d> cooperating with a lug 17<a> on the associated arm 16 or 17. The finger co-operates also with an arm 37 on a locking-lever 36 which is pivoted on a spindle 38 and has a second arm 39 co-operating with the associated lever 16 or 17. When, as shown in Figs. 1 and 4, the ribbon is being wound on to and off the spools 1, 2, respectively. (1) the locking-lever 36 associated with the spool 1 is in depressed position, the arm 39 being out of engagement with the arm 16, and the arm 37 locking the associated reversing-lever 30 by engagement with the firger 30d thereof, whilst (2) the locking-lever 36 associated with the spool 2 is in raised position, the arm 39 engaging the arm 17, and the arm 37 being released from the finger 30<d> of the associated reversing-lever 30. When the ribbon has been wound off the spool 2, the associated reversing-lever is swung by the tension of the ribbon and the arm 17 is rocked by the finger 30<d>, aided by the roller 19, the driving- shaft being thereby moved longitudinally to reverse the feed. Thereupon (1) the lever 16 raises the locking-lever associated with the spool 1 and releases the associated reversing-lever, and (2) the lever 17 permits the associated locking- lever to fall, and the associated reversing-lever is returned to normal position by a spring and is locked by engagement of the finger 30<d> with the locking-lever. When the ribbon has been wound off the spool 1, the reversing-lever associated therewith is rocked and the arm 16 is rocked to reverse the feed in a manner similar to that described above. The above-described mechanism is supported on two brackets 42 which are connected by a yoke 40 and are attached to the top plate 34. The arms 37, 39 of the locking-levers may as shown in Fig. 9 consist of two independently pivoted members connected by a blade spring 45. If the ircreased tension of ribbon during reversal causes excessive pressure of the finger 30<d> on the member 37, the member 39 is moved independently by the associated arm 16 or 17, and the member 37 is raised by the spring when the tension of the ribbon is reduced after reversal. The spring drum 48, Fig. 13, drives the shaft 12 through a one-way clutch comprising fast and loose toothed-members 50, 51 on the hub 49 of the drum, the member 51 driving a pinion 47 on the shaft and being normally held in engagement with the member 50 by means of a spring 53. The meshing teeth of the member 51 and the pinion are arranged obliquely so as to urge the member outwards, the movement being normally resisted by the spring. When, however, the ribbon mechanism jams, the member 51 is moved axially out of engagement with the member 50, and the ribbon mechanism is thereby prevented from arresting the carriage.