Patent GB-982764-A (GB)
Title: An electric typewriting machine
IPC: B41J23/34
Filed: 1962-02-28
Abstract: 982,764. Typewriters. OLYMPIA WERKE A.G. Feb. 28, 1962 [April 10, 1961], No.7799/62. Heading B6F. Type lever actions; electromagnetic key actions. In an electric typewriter key-lever contacts T 1 -T 45  select their associated type-bar control magnets Stl to St 45 , the armatures of which couple their associated type-bar mechanisms to a common operating rail (not shown), which in turn is displaced through a short operating stroke by a main operating magnet H 1  . . . H 4 , the circuit arrangement being characterized in that the main operating magnet is not energized directly by a cut-in relay A, but indirectly through a control relay D, the current path of which can be interrupted either by break contacts h 1 , h 2  on actuation of the main operating magnet H 1  . . . H 4 , or by a break contact C 1  of a single stroke relay C, or through a contact C 1  of a single safety relay B, so as to make the operation of the type-bar control magnets dependent on the release of the first actuated key. On the depression of the contact T 1  the relay A is energized to close its contact a, whereupon the relay D is actuated, via contacts a, b, h 2 , closing contacts d 1 , d 2 , d 3  and changing over a contact d 4 , whereby the relay C is energized and becomes self-holding by changing over its change-over contact c. The make contact d 1  acts as sealing contact for the relay D and contact d 3  energizes the main operating magnet H 1  . . . H 4  to effect impression of the type bar (not shown). Key interlocks.-On simultaneous depression of two or more contacts T the excessive current is caused to flow through the shunted relay B and resistance R, whereupon the contact b is opened and relay D is not actuated and the impression of the type-bars does not take place as the main operating magnet H 1  . . . H 4  is disabled. Repeat mechanism.-To facilitate repetitive type impression, a key lever contact T 47 , having a normally closed contact is depressed in conjunction with one of the contacts T 1  to T 45 , so that the single-stroke relay C is disabled and the relay D and main operating magnet H 1  ... H 4  are intermittently operative as the contacts d 1  and h 2  are alternatively closed and opened, due to alternate operation of the relay and main magnet. Letter-spacing mechanism; key actions.-On energization of the relay D the contact d 4  is changed over to actuate the escapement mechanism relay E, which closes its contact e and a capacitor C 1  becomes charged. When the main operating magnet H 1 . . . H 4  is energized through closed contact d 3  and the type impression takes place, the relay D is deenergized through contact h 1 , and contact d 4  is returned to the position shown in the Figure, but relay E is maintained in operative position by the discharging capacitor C 1  and the closed contact e renders a transistor Tr 3  conductive to actuate a magnet S which operates the carriage escapement mechanism. A make-contact key T 46 , acting as a space-bar enables the relay contacts d 4  and e to be bridged over to obtain a letter-spacing by direct actuation of the carriage escapement magnet S. Margin stop devices.-Connected in the circuit of relays A and B is a break contact f,  which is opened on actuation of the carriage return device (not shown) to prevent a type impression during this operation.