GB1173230A - Improvements in or relating to Typewriters and Similar Writing Machines - Google Patents

Abstract

1,173,230. Selective printing. OPTIMA BUEROMASCHINENWERK ERFURT VEB. 22 July, 1967, No. 33808/87. Heading B6F. A mechanism for the axial selection of a particular row of characters on a set of typewheels on a carriage 1, itself moving in letterspace direction, comprises a known letter-space device, 2-5, for effecting single steps, but superimposed on this is a positive movement derived from a pair of electromagnets 22, 28 and a differential gear mechanism so that different letter-spacing such as zero, single and double steps may be effected. The carriage with its two or more type-wheels 1,2, Fig. 4, is tensioned to the right by a spring drum 3 under control of the wheel 4, and a hammer, shown by shaded area, Fig. 4, moves also one step at a time. When a character next to be printed is in the same wheel one step of the carriage occurs, when the next character is in a row to the left two steps of carriage are required (position II to position III) and if the next character is on a wheel to the right of the wheel being used no step of the carriage is required (position IV to position V). The different spacing is arranged by the operation of the electromagnets 22, 28 which by the differential gear mechanism 6-9 cause an extra space to be added or subtracted to the normal spacing. When a space is to be subtracted the carriage is held stationary by a pawl 30 to prevent unnecessary forward and backward movement of the carriage.