Patent GB-1029481-A (GB)
Title: A typewriter with a proportional-step letter-spacing control arrangement
IPC: B41J19/58
Filed: 1963-01-16
Abstract: 1,029,481. Typewriters. OLYMPIA WERKE A.G. Jan. 16, 1963 [Jan 18, 1962], No. 1965/63. Heading B6F. Mechanism for controlling the movement of the typewriter carriage so that letter-spacing movements corresponding to the widths of characters is obtained comprises stops 45 1  to 45 8  Fig. 6 (not shown) for engaging the teeth of the escapement member 43 of the carriage and the number of which corresponds to the fractions of the teeth pitch required for spacing, a number of consecutive stops corresponding to the spacing required being withdrawn by electromagnets 31 1 -31 8  controlled by a step-selection twitch 20 movable proportional to the carriage movement and to which a pulse is fed from one of a number of lines 2. 7, the particular line 2... 7 being selected by the type key operated. Operation of a type-key 10, Fig. 1a (not shown), closes a switch 10<SP>1</SP> to connect an electromagnet 32 between a negative line 11 and the collector of a power transistor 15. A second switch 10<SP>11</SP> is also closed by the key preferably with slight delay and connects a positive line 12 to the transistor emitter via a diode 13<SP>1</SP>. The transistor 15 is connected through a delay device 34, Fig. lb (not shown), and a transistor 35 to electromagnets 33 to cause operation of a drive rocker 36 common to all the type-bar mechanisms. The rocker 36 causes actuation of the type-bar corresponding to the key actuated, through a coupling member moved into its path by the selected electromagnet 32. Each switch 10<SP>11</SP> is also connected through a diode 13<SP>11</SP>, a shift-key operated switch 17, and a switch 18 for altering the spacing to one of the lines 19 2 - 19 7  so that a pulse corresponding to the desired spacing is fed to the switch 20. Each line 19 is connected to a corresponding fixed contact 21<SP>1</SP> 2  . . . 21<SP>1</SP> 7  of the switch 20 which also has two unconnected contacts 21<SP>1</SP> 1 <SP> </SP>and 21<SP>1</SP> 8 , the number of fixed contacts, viz., eight, corresponding to the units of subdivision of the pitch of the teeth on the escapement member 43. The fixed contacts are connected by diodes 22 so that a pulse to one of the fixed contacts passes also to the other contacts of lower number, e.g. a pulse to contact 21<SP>1</SP> 3  also passes to contacts 21<SP>1</SP> 2  and 21<SP>1</SP> 1 . A rotatable part 11 of the switch 20 is driven by gearing from the typewriter carriage and carries eight contacts 23<SP>1</SP> 1  ... 23<SP>1</SP> 8  which engage the fixed contacts 21<SP>1</SP> in turn and have connections 27 to eight slip rings 26 1 ...26 8  engaged by fixed contacts 21<SP>11</SP> 1 ...21<SP>11</SP> 8 . Each of the contacts 21<SP>11</SP> is connected through a transistor 30 1  ... 30 8  to an electromagnet 31 1  ... 31 8  and each electromagnet 31 operates to withdraw one of the stops 45 1  ... 45 8 . Assuming that the switch contacts are initially in the position shown in Fig. 1b and the stop 45 1  is abutting against a tooth, if depression of a key causes a pulse to be applied to line 19 3 , for example, the pulse passes to contacts 21<SP>1</SP> 1  ... 21<SP>1</SP> 3 , electromagnets 31<SP>1</SP> 1  ... 31<SP>1</SP> 3  are energized, stops 45 1  . . . 45 3  are withdrawn and the member 43 and carriage move until the tooth abuts against stop 45 4 , i.e. a spacing of three units has occurred. Similarly, subsequent depression of another key causes a pulse along one of the lines 19 2  ... 19 7  to effect withdrawal of consecutive stops 45 following the stops 45 1  ... 45 3  so that the required spacing is achieved. In order to make the switch 20 sufficiently large for a satisfactory drive to be provided, a number of sets of contacts 23<SP>1</SP> 1  ... 23<SP>1</SP> 8  in parallel are provided on the rotary part 11. For carriage-return or tabulating, operation of a switch 41, Fig. 1b (not shown), causes all the stops 45 to be withdrawn. The electromagnets 31 instead of operating directly on the stops 45 may act to displace members 46 &c., Fig. 7 (not shown), into the path of a single electromagnet 37 which effects withdrawal of the selected stops indirectly through the members 46 &c.