Patent GB-947131-A (GB)
Title: Ribbon mechanism for typewriter
Inventor: MORRIS JOHN CHARLES
IPC: B41J35/23
Filed: 1961-01-31
Abstract: 947,131. Typewriters &c. SPERRY RAND CORPORATION. Jan. 31, 1961, No. 3631/61. Heading B6F. A typewriter or similar machine has means for mounting both fabric and paper carbon ribbon spools. The fabric ribbon is driven from a shaft which can be engaged with one of two reels to feed the ribbon in either direction and means are provided to disengage both reels and to hold the shaft thus by detent means to allow manual operation of the reels. An alternative paper feed mechanism in an alternative mounting gives a unidirectional feed. A fabric ribbon 20, Fig. 1, wound and unwound from reels 25, 26 mounted on shafts 16, 17 is driven alternately through gearing 21, 23 or 22, 24 from a shaft 11 in turn driven through a friction clutch 14 and a step by step clutch 47  actuated through an arm 48 from a ribbon actuator bar. Automatic reversal means of the feed is effected by cams 27, 28 while manual reversal or disabling of the drive can be effected by a single knob 38. Raising a cover 30 allows a slide 50 to rise so that the knob 38 can operate its arm 34 which by a toggle arrangement and a lever 42 can shift the shaft 11 to engage either shaft 16, 17 or shift it to an intermediate position in which neither shaft is engaged and in which position the mechanism is locked by a pin 37 entering a slot 60. According to which end of the slot 60 the pin 37 is positioned so upon replacement of the cover 30 a corresponding shaft 16 or 17 will be engaged and driven by the shaft 11. Alternatively, a paper carbon ribbon 65, Fig. 7, is employed which is fed from a spool mounted vertically on the external face of a frame member to a take-up spool 73 mounted in shoots 82, 83 of the frame member 12. The feed comprises an extension 127 of a power roll 15 which engages an elliptical wheel 126 to actuate a link 131 to cause feed movement of friction wheels 102, 107 between which the ribbon 65 passes. The wheel 126 is normally held out of contact with the extension 127 by a nose 122 of a slide governor 115 but this slide is withdrawn, to allow an intermittent feed movement, by a nose 137 of an actuator bar engaging a hook 138. The feed movement is controlled by a lever 110 which in the position shown allows, on actuation of a character key, half a revolution of the wheel 126 before nose 122 cams it out of contact with the extension 127. If the lever 110 is moved so that its indentation 135 engages the other cleat 134 the slide 115 is moved so that the nose 137 no longer engages the hook 138 and no feed movement can be initiated. On further movement of the lever 110 the slide 115 is moved until its nose no longer engages the wheel 126 and continuous feeding occurs to complete winding from the supply reel. A roll 161 of a pivoted lever 158 extends through a hole 162 to engage the ribbon wound on to the take-up reel and when it is nearly full through a link 157 rotates a drum 153 so that a mark 154 appears through a slot 155 to indicate that the reel is full. A similar indicating device shows when the supply roll is nearly empty. Specification 947,132 is referred to.