Patent GB-596685-A (GB)
Title: Improvements in and relating to typewriting and like machines
IPC: B41J3/24
Filed: 1945-06-07
Abstract: 596,685. Typewriters &c. BRUMHILL, C. W. June 7, 1945, No. 14351. [Class 100 (iv)] Ink-ribbon mechanism.-A typewriter or like machine, particularly for typing mirrorscript master sheets, comprises a carriage which traverses in typing and in the reverse movement a take-up device having a stationary location, for taking up used ribbon discharged from the carriage, ribbon-guiding devices for traversing a length of the ribbon with the carriage during letter-spacing to present successive areas of the ribbon at the typing station and to discharge used ribbon to the take-up device, the ribbon-guiding. devices including two guides for a final straight lap of the ribbon, one guide having a stationary location towards one end of the machine, and the other guide being mounted on the carriage beyond the centre line thereof towards the other end of the machine, and the length of the lap when the carriage occupies its extreme position at the other end of the machine being at least equal to the length of traverse. A ribbon 13 is drawn from a supply spool 128, Figs. 6 and 15, passes over vertical guide rollers 33, 34, 35, then under an horizontal roller at the front of the machine, over an inclined guide to the typing station, then over an inclined guide and horizontal roller to vertical guide rollers 40, 41, and then via a roller 42 to a take-up spool 30. The guide rollers engage the untreated side of the ribbon and are of a length greater than the width of the ribbon to avoid removal of the coating from and scraping the edges of the ribbon. The spools 128, 30, and the rollers 33, 42, are mounted on a stationary frame 32 fixed to the back of the machine, and the remaining guide rollers and guides are mounted on the usual paper carriage 4 whereby as the carriage travels for letter-spacing the ribbon is pulled off the spool 128 and released to the spool 30, the latter being driven by a spring drum 43, see also Fig. 8, wound up during reverse traverse of the carriage 4 by means of a cord 44 anchored to the latter at 45. A clamp 66, Fig. 14, for securing the ribbon to the carriage during letter spacing comprises a fixed part 66a, and a movable part 66b actuated by a spring- pressed lever 67. When the carriage rack is raised for reverse traverse or tabulating, a lever 70 one end of which rests on the usual carriage rack is rocked and through a lever 71 and rod 72 rocks the lever 67 to open the clamp and release the ribbon. The clamp is also opened on reverse movement of the carriage other than by working the release lever or the tabulator, by means of a bar 74, Fig. 6, which is fixed to the carriage, is connected to the lever 71 and passes through a stationary guide 75, a spring-pressed ball working between the bar 74 and an inclined surface on the guide serving to lock the bar to the carriage during reverse movement only of the latter. The drum 43, Fig. 8, drives the spool 30 through a ratchet disc 46 on the drum, a disc 47 carrying a pawl 48 engaging the ratchet, and a slip drive being provided consisting of a spring washer 50 between the disc 47 and a disc 49 connected to the spool. As the diameter of the roll of ribbon increases, the drive slips and an even rewind is provided. The spool 128 is connected by a spring-pressed lever 63, Fig. 6, to a disc 62 braked by a spring washer. Both spools are locked during reverse movement of the carriage by pawls 56, 64 engaging teeth on the discs 49, 62 respectively, the pawls being actuated from a lever 57 one end of which overlies the carriage rack. The main-carriage motor spring can be let down when the hectograph ribbon is in use, by means of an escapement 83, a Geneva stop device 82 preventing over-release. Specifications 596,682 and 596,684 are referred to.