Patent GB-233407-A (GB)
Title: Electric type wheel actions for typewriting machine
IPC: B41J1/32
Filed: 1924-02-05
Abstract: 233,407. Marks, E. C. R., (Scherbius & Ritter). Feb. 5, 1924. Electric type-wheel actions. - In electric actions of the type in which a rotating typewheed is mounted to swing about a shaft approximately parallel to its axis and strikes the platen by momentum after its arrest in predetermined positions for character selection by means of a stop device and of a toothed wheel on the typewheel shaft, the stop point coincides approximat,ely with the swinging point of the typewheel. The type-wheel 2, Figs. 1 and 2, and the toothed wheel 11 may be mounted on a shaft 3 continuously driven from an electric motor 4 through a friction clutch 26 and elastic connection or cardan joint 5, the shaft 3 swinging about a parallel shaft 9 by means of a link 7 loosely embracing the shaft 3. A spring 10 normally maintains the type-wheel out of contact with the platen 1 and is adjustable to vary the impression by means of a toothed wheel 27 co-operating with a stop-lever 29 and connected to one end of the spring. A brush 17 on the shaft 3 and co-operating fixed commutator segments 18 are connected through key-switches 20 to a battery 22 and an electromagnet 15, the armature 14 of the magnet 15 being carried by a stop-lever 13. The arrangement is such that, on the depression of any key 20, the magnet 15 is operated when the shaft 3 has rotated to bring the brush 17 into contact with the corresponding segment 18, and the end 12 of the lever 13 then engages the wheel 11 and stops the type-wheel 2 with the corresponding character opposite the platen, the wheel 2 then swinging against the platen by momentum about an axis through the points 5 and 9. The motor 4 may be key-controlled instead of continuously driven, and the friction clutch 26 may be omitted and the motor stopped with the wheel 11. To ensure that the type strikes the paper perpendicularly, the stop point 12 may be arranged on the axis of the shaft 9 and both in the tangent plane to the platen at the impression point, the wheel 11 being then larger than the wheel 2. In a modification, Fig. 4, avoiding too sudden stoppages of the wheel 2, the toothed wheel 31 on the shaft 3 gears with a toothed wheel 30 on a parallel shaft 32 and the shaft 3 is connected to the shaft 32 by a swinging link 40. The key-controlled electromagnet 38 operates a brake for the shaft 32, the type-wheel striking the platen by momentum_on the stoppage of the wheel 30. The brake may comprise a band brake, or an iron plate 35 at the lower end of the shaft 32 and co-operating with pole-pieces 39, the plate 35 being connected to the shaft 32 by a spring 36 and spaeed from the pieces 39 or being rigidly mounted on the shaft 32 and continuously in contact with the pieces 39. The power drive may act on the shaft 32 as well as on the shaft 3, being uncoupled from the shaft 32 on movement of the plate 35. The shaft 3 may be flexible and the joint 5 omitted. The joint 5 may comprise a membrane 91, Fig. 7, clamped at its edge to a dished plate 90 on one part 3a of the shaft 3, and at its centre to a flange on the other part 3b of the shaft, so that the part 3b can rock about the part 3a through a small angle.