Patent GB-145658-A (GB)
Title: Improvements in ribbon reversing mechanism for typewriters
IPC: B41J33/40
Filed: 1920-06-30
Abstract: 145,658. Victor Typewriter Co., (Assignees of Hagerstrom, J. A.). May 16, 1918, [Convention date]. Ink-ribbon mechanism.-In automatic feed-reversing mechanism comprising an interponentlever for moving into and out of mesh gears on a driving-shaft and a countershaft, the interponentlever is normally held in inoperative position by a holding-lever which, when moved to release the interponent-lever is locked until the feed has been reversed. In the mechanism shown in Figs. 2, 3, 4, and 8, a driving-shaft 1 is provided with bevelwheels 3, 4 in alternate engagement with bevelwheel 9, 10 on countershafts 11, 12 geared to the shafts 15 of the ribbon-spools 16. Each spool is associated with the following reversing-devices. An arm or holding-lever 22, formed on a U-lever 20, pivoted on a pin 21, Figs. 3 and 4, is held by a spring 28 in engagement with the arm 23 of an interponent lever or bail 24 mounted on the associated shaft 11 or 12, a roller 26 being mounted on the arm 25 of the bail and being normally above and out of engagement with a cam 5 or 6 on the driving-shaft. A rocking plate 35, Fig. 4, mounted by pins or trunnions 36 on the framework, is formed with a finger 37, normally resting on the arm 22, and carries a dog 32 which co-operates with a star-wheel 31, Fig. 3, on the spool shaft 15. The dog is pivoted on a pin 33 on the plate and is held by gravity in contact with a stop on the plate. The dog and plate are preferably made of non-magnetic material. The ribbon 17 passes between a stationary post 18 and a movable guide 19 consisting of an arm on the lever 20. When the ribbon has been wound-off one spool, the end buckle 38, Fig. 4, rocks the arm 19 and causes the arm 22 to release the bail 24. The roller 26 then drops and oo-operates with the associated cam to move the driving-shaft longitudinally; or, if the roller is caught by the periphery of the cam, a varying idle period occurs before the roller drops, the idle periods causing the ribbon to be struck at different points during successive runs. When the arm 22 is rocked in the above-described manner, the plate 35 is released and the finger 37 locks the arm. Upon reversal of the feed, a tooth of the star-wheel rides over the bevelled top of the dog, which is then prevented from rocking by the stop, and causes the finger 37 to release the arm 22, the spring 28 then returning the parts to the normal position. The arms 25 of the bails 24 are formed with stop-fingers 27 which engage the driving-shalt when the rollers drop. To prevent both pairs of bevel-wheels from being left in gear and thereby locking the machine, the cams 5, 6 are arranged to form stops which oo-operate with the peripheries of the bevel-wheels 9, 10 respectively. The cams 5, 6 are each formed with two or more lobes 7, 8 respectively, the lobes 7, 8 being staggered relatively to prevent the driving-shaft from being left in a position in which neither pair of bevel-wheels is in engagement. The following device is provided for retaining the driving-shaft in the set position and for assisting the cams to move the driving-shaft. A bell-crank 47, Fig. 8, is provided with a pin 44 engaging a collar 42 on the driving-shaft and is formed with V-notches 48 engaging a lug 49 on a lever 50 which is urged towards the bell-crank by a spring 52.