Patent GB-103510-A (GB)
Title: Apparatus for Writing and Projecting the Writing on to a Screen.
Inventor: COOKE GEORGE FREDERICK
IPC: G03B21/26
Filed: 1916-01-26
Abstract: 103,510. Cooke, G. F. Jan. 26, 1916. Record-controlled electric type-lever machines: papersupports. - In an apparatus for projecting typewritten matter on a screen, comprising a typewriter adapted to print on a strip t passing over a transparent or semi-transparent platen B arranged between the screen and a source of light, the typewriter may be operated by an adjacent or a distant keyboard through mechanical or, as shown, electric connexions. The electric connexions may be actuated independently of the keyboard by a controlling-strip. For this purpose, there is provided a row of contacts pressed by supporting-springs towards a conducting-roller, round which a perforated strip is fed, the blank parts of the strip separating the contacts from the roller and the perforations permitting selected contacts to touch the roller periodically. Or the perforated strip may be replaced by a roll or strip of metal, which is fed round the couducting-roller and is formed with contacts which periodically engage the first set of contacts. As shown, the type-members consist of levers F mounted in a carriage C which is traversed on rails D for letter-spacing, the types G printing on the strip t, which passes over the transparent platen B and is moved downwards for line-spacing by means of rollers U, V. The typelevers are connected to armatures H arranged in solenoids Z and carried by returning-springs y provided with contacts 2 adapted to engage contacts 1, 3. On depressing a key or contact x, one of the solenoids is energized, and its core H is lifted to operate the associated type-lever. The movement of the armature breads the contacts 2. 3 and closes the contacts 1, 2, thus energizing a solenoid S which is secured to the carriage C and operates the following letter-spacing mechanism. Electric letter-spacing mechanism; carriage-releasing arrangements; carriage-returning mechanism: line-spacing mechanism.-A rack N, on the base Z supporting the rails D, co-operates with an escapement K consisting of two toothed disks journaled in a frame I which is pivoted at J to the carriage C. The armature R of the solenoid carries a pawl P for operating a ratchet-wheel secured to the disks. The notches in one disk are opposite the teeth of the other disk, and the pitch of the teeth is equal to, or a fraction of, a letter-space. The carriage C is propelled by a chain or cable 10, which is driven in one direction, for letter-spacing, by a weight 4, and in the other direction, for carriage-return, by the armature of a solenoid 9 in the circuit of a key. The cable passes over guide-pulleys 5 .. 8 arranged so that the frame is pressed towards the rack N during the letter-spacing movement, and is rocked away from the rack to release the carriage at the beginning of the return movement. The escapement K may be replaced by a positive feeding-device consisting of a screw. For differential spacing, the solenoid S may be provided with a number of windings arranged to cause the armature R to move different distances into the solenoid, the windings being in the circuits of keys associated with letters of different widths. The strip t is line-spaced by means of a pawl carried by the lever W engaging an inclined slot c in the carriage C, the pawl being operative when the carriage is returned by the solenoid 9; or the lever may be operated by a separate solenoid.