Patent GB-777844-A (GB)
Title: Improvements relating to typewriters
IPC: B41J3/36
Filed: 1954-07-01
Abstract: 777,844. Typewriters. SUIF, F. A. July 1, 1954 [July 3, 1953], No. 19373/54. Class 100(4) In a typewriter consisting wholly or chiefly of moulded plastic parts and chiefly intended to be a toy, the platen or cylinder carriage is lifted as a body to effect case shift while a frame like member slidable in the case is actuated by the type bar control levers to effect letter spacing, ribbon feed and ribbon vibrating. The framework: comprises two half shells 1, 2, Fig. 1, of moulded plastic connected by two crosspieces and an apron 5, defining a notch 8 at the printing position, supporting side plates 9, 10 to which the ends of a cord 12 of steel wire are attached on which identical moulded type bars 14 are pivoted. A circlip 15 connected to lugs 16, 17 supports the type bars in a rest position and the type levers 20 are pivoted on axles 19 which pass through sleeves 18 on the shells, 1, 2. The free ends of the, levers 20 are connected by rods 24 directly to the type bars 14 and are disposed directly in front of crosspieces 30 of a frame member 29 the sides 27, 28 of which slide in guides in the shells 1, 2. Case shift: The cvlinder carriage 40, Fig. 5, is guided on a table 33 which has a support 32 bearing against a bar (not shown) connected to a cam 37 which by a rod 38 connected to a key raises or lowers the whole table and carriage to effect case shift. Letter spacing: The carriage 40 is urged in a letter spacing direction f3 by a spring 63 and is held for escapement by a pawl 56 engaging a rack 61. The pawl 56 is freely mounted on a tubular element 51 in the support 32 and is held by a spring 52, acting in tension and torsion, to the left in Fig. 7 and against a stop 57 on the table 33. The pawl has two teeth 58, 59 offset by a distance greater than the thickness of a tooth 60 of the rack 61 and spaced widthwise less than the width of a tooth 60. When a key 21 is depressed a lever 20 acts on a crosspiece 30 to move the frame 29 in the direction f4 so that a yoke 67 moves the pawl 56 to the right, Fig. 7, so that, after the tooth 59 has entered the rack 61, the tooth 58 disengages allowing the carriage to be moved by the spring 63 until the tooth 59 is contacted. The torsion effect of the spring 52 keeps the pawl against the stop 57 and on release of a key the spring restores the pawl 56 and the frame 29 the tooth 59 disengaging after the tooth 58 has re-entered the rack 61 to allow the carriage to move further in a letter spacing direction until the tooth 58 is again engaged by a tooth 60. Ink ribbon mechanism: A pawl 83 fixed to the frame 29 engages one or other of the tooth crowns 82 of the spools 81 to effect ribbon feed. Alternatively the spools may be mounted vertically. A ribbon vibrating lever 77 is pivoted at 78 and has a nose which normally engages a cylindrical part 56a of the pawl 56 but when this is moved by the frame 29 it is forced against a frusto-conical part 56b which pivots the lever 77 and the ribbon into the printing position. Line spacing: The cylinder 42 is mounted by axles 43, 44, Fig. 1, in a deflection guide 41 and is provided with notches 47 at one end and with a spring 48 at the other which holds the notches engaged with a finger 46. A knurled knob 45 allows the cylinder to be rotated to the next notch for line spacing .