| 摘要 |
1,077,522. Typewriters etc. G. MANUS. Feb. 19, 1965 [Feb. 29, 1964], No. 7382/65. Heading B6F. [Also in Division G4] A type-bar is selected by closing the appropriate key switch to energize the associated type-bar-selecting solenoid, all the solenoids being connected to a common current-limiting device which can only provide sufficient current to actuate one type-selecting-solenoid at a time, and after the type selection a common striking mechanism is actuated to effect printing. Selection of type bars in too rapid a succession may be avoided by delaying the triggering of a monostable circuit which supplies the solenoidenergizing pulse, until a given interval has elapsed since the preceding type selection operation. Where selection of a type bar is controlled through a catch attracted by a type selecting solenoid, residual current in the solenoid may be sufficient to hold a catch which has rebounded into contact with the solenoid after a type selecting operation, and to prevent this, an RC circuit may be provided in series with the solenoid to effectively cancel the residual current and return the catch to its inoperative position. |
