Patent GB-191195-A (GB)
Title: Improvements in electrical actuating means for operating the type bars of typewriters and other key-controlled devices
IPC: B41J3/44
Filed: 1921-10-18
Abstract: 191,195. White, A. E., (Magnetic Power Transmitter Co.). Oct. 18, 1921. Electric driving-mechanism.- In electric driving- mechanism for typewriters and other key-controlled machines such as tyre-setting, type-casting, adding, or calculating-machines, of the kind in which the keys are associated with individual electromagnets, the keys move individual contact-members into engagement with a universal contact-bar without closing a circuit and then move the universal contact-bar to close the circuit of the selected electromagnet and in some cases, the circuit of a driving electromagnet. Since sparking occurs only at the contacts on the universal contact-bar, only a few contacts need be provided with platinum points, such points being omitted from the key-controlled contact-members. As illustrated in Figs. 3, 4, and 5, type-levers 3 are each connected to a lever 8 carrying a hook-link 12 connected to the rocking armature 21 of an electromagnet 20. The hook-links 12 co-operate with a common driving- member 24 secured to a rock-shaft 26 connected to the rocking armature 29 of one or more driving electromagnets 30. The key-levers .40 have blocks 53 for depressing contact-levers 50 into engagement with a universal contact-bar 45 secured to rocking arms 44 and adapted to engage a contact-spring 54 in circuit with the electromagnets 20, and a contact spring 60 in circuit with the electromagnets 30. The contact - springs 54, 60 may be each split longitudinally into two parts which are held at slightly different levels by screws 57, 61. On depressing any of the key-levers, its contact-lever moves the contact-bar into engagement with the contact-spring 54, and the circuit of the selected electromagnet 20 is closed, the associated hook-link 12 being thereby moved into the path of the driving-member 24. Thereupon, the contact-bar by engaging the contact-spring 60 closes the current of the driving electromagnets 30, and the driving-member lifts the selected hook-link and operates the associated type-lever. The rock-shaft 26 operates escapement mechanism for the paper carriage, the levers 40<1> of the spacing-bar 41<1> being arranged to close the circuit of the driving electromagnets. In some cases the selecting and driving electromagnets are arranged in the same circuit, the heavy driving electromagnets lagging behind the selecting electromagnets. When two or more driving electromagnets are employed they may be associated with contacts or armature stops arranged so that the driving-member is operated initially by all the electromagnets, and finally by only one of the electromagnets. In the preferred form of this device, the electromagnets 30, 30<1>, Fig. 11, have sliding cores 29, 29<1> provided with pins 33 engaging a fork 27<1> and a finger 28<1> on the rock-shaft 26 of the driving-member 24, stops 31, 31<1> being arranged in the paths of the cores. In operation, both cores are operative until the core 29<1> is arrested, whereupon only the core 29 is operative, the finger 28<1> rocking idly.