Patent GB-1178908-A (GB)
Title: Ink ribbon cartridge for a typewriter, teleprinter or similar office machine
IPC: B41J33/518
Filed: 1967-09-20
Abstract: 1,178,908. Ink-ribbon mechanism. ING. C. OLIVETTI & C. S.p.A. 20 Sept., 1967 [20 Sept., 1966], No. 42720/67. Heading B6F. Ink-ribbon cartridges.-An ink ribbon cartridge adapted to be removably mounted on a typewriter or like machine comprises a box 45 open at its lower side, a ribbon guide 48 being secured to the box 45 and being vibrated bodily therewith, spools 49 being mounted for rotation about pins 50 secured to the box 45 and being locked into the box by a pair of levers 54 pivoted at 52 and urged apart by a spring (55), Fig. 3 (not shown), each lever contacting the ribbon on a spool, and the levers having lugs 56 whereby the levers may be closed together manually to unlock the spools from the box 45. The box is removably attached to a plate 8 of the machine by a bayonet joint comprising slots 79 in an element 78, which slots accommodate pins 81 formed on a pillar 37 secured to the plate 8. A snap-operating knob 71 operates the bayonet joint. The ribbon may be changed by removing the box 45 from the machine and disengaging the levers 54 from the spools 49. The cartridge may be made of transparent plastics material. Vibrator mechanism.-The ink ribbon in the guide 48 is vibrated into and out of the space between type wheels 6 and a platen 7 by a cam 13 rotated by a mainshaft 4 and acting through an arm 11 to rock the ink-ribbon mechanism as a whole about a pivot 10. The shaft 4 makes a half revolution counterclockwise for each printing cycle. Ink-ribbon feed.-A cam 31 mounted on the shaft 4 acts through a lever 28, link 27 and crank 26 to rock a shaft 24. Two cranks 23 are fixed to the shaft 24, each being pivoted at 22 to one of two pawls 19, each having a lug 18 which is thereby reciprocated by the crank 23 and acts to rotate a ratchet wheel 16. The spools 49 are each mounted on a ratchet wheel 16 and fixed with respect thereto by eccentric pins (17), Fig. 2 (not shown), engaging holes (51, Fig. 3) in the spools. Reversal mechanism.-Each pin 50 pivotally bears a three-armed lever 58, each lever being provided with a roller (62), Fig. 3) and pin (63) on one arm, and a pin 64 on a second arm, the third arms being interconnected by a spring (59). The ink ribbon passes between each roller (62) and its associated pin (63) and tends to turn the levers 58 by its tension. When the feed spool carries sufficient ribbon, a lug 65 formed on the associated lever 54 engages the pin 64 on the corresponding lever 58, thus preventing rotation thereof. When the thickness of the ribbon on the feed spool becomes less than a predetermined amount, the pin 64 is disengaged from the lug 65 and rotation of the lever 58 is permitted, whereupon the pin 64 engages a lug 66 formed on a lever 36 pivoted about the pillar 37, and rocks the lever 36. Pins (34, Fig. 2) formed on the lever 36 then act to disengage one pawl 19 from its associated ratchet wheel 16, and permit the other pawl to engage the other ratchet wheel, under the influence of a spring (32) urging the pawls apart, thus reversing the ink-ribbon feed. In case the tension of the ribbon fails to rock the lever, a clip is attached to each end of the ribbon, the clips being unable to pass between a roller (63) and pin (62), and thereby being effective to turn the levers 58 to reverse the ink-ribbon feed.