Patent GB-1208287-A (GB)
Title: A character-spacing mechanism
Inventor: VERMES PETER
IPC: B41J19/58
Filed: 1967-11-20
Abstract: 1,208,287. Typewriters &c. IRODAGEPIPARI ES FINOMMECHANIKAI VALLALAT. 20 Nov., 1967, No. 52692/67. Heading  B6F.  A letter-spacing mechanism for a power  operated typewriter having a carriage which is  spaced proportionally in accordance with the  width of type characters is provided with an escapement wheel 1, Fig. 1, which is biased by the carriage spring (not shown) in a clockwise direction and which following depression of a key and impact of a type character is imparted an initial angular displacement corresponding to one or two elementary letter-spacing units of the carriage by a first segment 3, depending on the disposition of a member 14 and a further displacement corresponding to a number of even elementary spacing units by a second toothed segment 2 co-operating with a slidable and rotatable stop 4, which when a slide 9 is disposed between its annular segment and a stop pin 20 on a lever 5 is rotated by an amount corresponding to a single elementary unit, whereby an odd number of elementary units may be imparted to the escapement wheel 1 when the stop 4 is actuated slidably and rotatably. In operation and following the depression of a key a bellcrank lever 6 is pivoted about a pin 21 to rock the segment 3 into a meshing engagement with the escapement wheel 1, the free arm of the bellcrank rocking a spring biased bellcrank 5 anticlockwise to disengage the second segment 2 from the escapement wheel 1. The escapement wheel 1 which was thus far held in an arrested position by the segment 2, whose rotation under the bias of the carriage spring was prevented by the pin 20, is rotated by the carriage spring in a clockwise direction and arrested in an angular position corresponding to  two elementary space units when the segment 3 abuts the member 14. Meanwhile the segment 2 has been rotated anticlockwise by the bias of a torsion spring 8, Fig. 2, to abut one of a number of teeth on the stop 4. When the segment 3 is disengaged from the escapement wheel 1 on anticlockwise restoration of the bellcrank 6, the segment 2 is re-engaged with the escapement wheel 1, which is enabled to resume its clockwise rotation until the segment is arrested by the stop pin 20. The additional angular displacement of the escapement wheel corresponds to a number of even elementary space units, the number depending on the extent of the axial displacement of the stop 4 by a shaft 25 which is actuated by a toothed bail 30, Fig. 4, through a link 33 and a bellcrank 29. The height of the teeth, which are disposed opposite respective key levers, corresponding to the even number of elementary space units. Should a letter-spacing corresponding to an uneven number of elementary space units be called for by a type face associated with a particular key then a further bail 31, having teeth of identical height, is actuated to rock a bellcrank 11 which displaces a blade 9, Fig. 1, be tween the stop pin 20 and the annular segment on the stop 4 so as to rotate the latter by an angular amount corresponding to a single elementary space unit the axial and rotary displacement of the stop 4 being cumulative. Letter spacing mechanism permits carriage to be spaced by a distance corresponding to any number of elementary space units from one to nine.  Sound deadening arrangements.-To prevent chattering of escapement wheel and segment teeth during carriage return a spring biased arm 17, Fig. 1, is inserted between the teeth of the escapement wheel 1 and segment 2, the arm 17 being restored by a strip 17a and spring 17b on completion of carriage return.