Patent GB-217982-A (GB)
Title: Improvements in or relating to letter-spacing mechanism for typewriters
IPC: B41J19/32
Filed: 1923-03-24
Abstract: 217,982. Farina, D. March 24, 1923. Letter-spacing mechanism.-In variable and differential letter-spacing mechanism for typewriters, the universal bar co-operating with the key-levers and the escapement is mounted to be capable of turning about its own longitudinal axis, and is provided with angularly displaced stops which project to different extents from this axis, and any one of which can be brought at will into co-operation with the key-levers. The extent to which the universal bar is rocked can thus be increased in order to obtain a free spaco after every type when required, or increased spacing for series of larger type.. To produce differential spacing according to the width of the characters printed, projections may be provided on the universal bar beneath the key-levers corresponding to characters of greater width. The escapement operated by the universal bar produces spacing of one, two, or more units according to the extent of oscillation of the bar. The universal bar 10, Fig. 2, pivotally mounted at 4, Fig. 6, in rocking arms 5, and depressed by the key-levers 2 operating the type-levers, is provided with two or more stops at different distances from the axis, two stops 31, 32 at 90‹ apart being shown, and one stop 32 being provided with projections under certain of the keylevers 2. A spring 15 normally retains the bar 10 with the stop 32 beneath the key-levers, so that a single or double spacing results according to the key-lever operated. The bar 10 is turned temporarily, to position the stop 31 beneath the key-levers, by means of a rod 13 and crank lever 14 controlled from a double-space key or from other parts of the typewriter, for example, from mechanism bringing a set of large type into printing positon, a double space then being produced at each type impression. An arm 6 on the shaft of the arms 5 is connected by a link 7, Fig. 8, to a bell-crank lever 17, Figs. 8, 16, and 17. The lever 17 carries a stationary abutment 19, a stop 12 normally engaging a tooth 11 of the sprocket-wheel 13 of the carriage feed, and an intermediate stop 12<1>. The stops 12<1>, 12, are pivoted to the lever 17 at 21<1>, 21, and are urged by springs 22, 20 towards the position shown in Figs. 16 and 17, in which the stop 12 is clear of the teeth of the sprocket 13, and in which the stops 12, 12' are retained by a heel 23 and a lug 24 on the stop 12<1>. Normally the tooth 11 under the action of the carriage spring holds the stop 12 against the lever 17, a lug 25 on the stop 12 holding the stop 12<1> also against the lever 17. The stop 12 is rigidly connected to an arc-shaped sub-stop 26. A single carriage feed is produced when the lever 17 is rocked so that the tooth 11 moves off the stop 12 on to the stop 12<1>, the stop 12 then being pressed into engagement with the lug 24 by the spring 22. On return of the lever 17 to its normal position under the action of a spring 18, the tooth 11 passes behind the stop 12 and engages the edge 26<11>, Fig. 17, of the substop 26, the tooth 11 being then urged forward by the carriage spring and moving the sub-stop 26 so that the stop 12 engages the next tooth of the sprocket-wheel 13. A double-space feed is produced when the lever 17 is rocked so that the tooth 11 passes off the stop 12, over the stop 12' and on to the abutment 19, the stops 12, 12' then moving into the position shown in Fig. 16. On the return movement of the lever 17, the tooth 11 engages the side 26<1> of the sub-stop 26 and prevents complete return of the lever 17 until the tooth 11 has passed beyond the sub-stop 26. The next tooth 11<1> passes the stop 12 whilst the tooth 11 is in engagement with the sub-stop 26, and then passes behind the stop 12 and clear of the stop 12<1> and engages the edge 26" of the sub-stop 26. The tooth 11<1> then moves forward without having engaged either of the, stops 12, 12' and operates the sub-stop so that the stop 12 engages the third tooth 11<11>.