Patent GB-313734-A (GB)
Title: Improvements in typewriters having type-carriages
IPC: B41J3/28
Filed: 1928-05-29
Abstract: 313,734. Marks, E. C. R., (Elliott-Fisher Co.). May 29, 1928. Type-carriages; type-lever machines.-A type-carriage is supported for letter-spacing movement by means arranged entirely at the rear of the type-carriage and comprising upper and lower members co-operating with the stationary framework, the arrangement preventing the support from interfering with the visibility of the writing. The printing-mechanism may comprise type-levers mounted in a horizontal segment and arranged to strike forwards and downwards on a flat platen 1, the keyboard being arranged in elevated position to render visible the writing. 'The machine may comprise also the letter-spacing, back-spacing, carriage - releasing, tabulating, and ink-ribbon mechanisms described below, the inkribbon mechanism being so arranged as to prevent the inkribbon from interfering with the visibility of the writing. The typecarriage A, Figs. 1 and 2, comprises side plates 1, front and rear bars 2, 3, a tie-rod 7, and superposed plates 14, 16 supporting action bell-cranks 31 and typelevers 27 respectively, the plate 16 being suspended from the plate 14 by means of brackets 17, 18. The carriage is provided at the rear with a three-point support consisting of a top roller 10 and two bottom rollers 20 engaging top and bottom tracks 11, 22. The roller 10 is mounted in a projection 8 at the middle of the bar 3, and the rollers 20 are mounted in blocks 21 depending from the rear corners of the plate 14. Each block 21 carries also a pair of rollers 24 engaging opposite faces of the track 22. The track 22 forms part of a stationary frame 12, and the track 11 is carried by a bar 149 which is secured to standards 150 on the frame and has a flange 152 arranged over the roller 10. The flange is tapered towards the ends, and on moving the carriage out of the central position it can be tilted rearward and then lifted out of the machine. The bar 149 carries a scale 151. The frame 12 may support also a platen 12<a> associated with line-spacing mechanism. The key-levers 35 are pivoted in a comb on the bar 3 and are connected by links 34 to the bell-cranks 31, these being connected by links 30 to the heels of the typelevers 27. The bell-cranks are pivoted in an arcuate comb 15 at the front of the plate 14, and the type-levers are pivoted in an arcuate comb 28 on the plate 16. The type-levers are normally vertical and are held in contact with an arcuate cushion 29 by means of springs 32<a>. The springs are disposed radially and are connected to the bell-cranks and hooks on an arcuate bar 32<c> under the plate 14. 'The action imparts accelerated movement to the type-levers, since the paths of the pivotal connections 27b, 27<a> of the links 30 are initially in approximate alignment with the ment during the stroke of the type-levers. Rebound of the type-levers from the cushion 29 is prevented, since the pivots b of the bell-cranks are initially at right-angles, and approach alignpivotal connections 27<a>, 27b. To ensure an easy start, the links 34 are so arranged that they are initially, at right-angles to the arms 33 of the bell-cranks. Aligning for impression.-An aligning-guide 36, Fig. 2, projecting from the plate 16 is formed with a converging throat 37 for receiving lugs 38 on the type-levers 27. Letter-spacing mechanism.-The type-carriage A, Figs. 2 and 5, is provided with escapement mechanism 40 which is mounted between the bracket 18 and a bracket 41 and comprises an escapement wheel co-operating with dogs 40<a>, 40b, and a pinion 39 gearing with a rack 38 on the frame 12. The type-carriage is propelled by a tape 90 connected to a spring drum 89. A universal bail 49, operated by lugs 50 on the action links 30, is pivotally suspended by means of arms 48 from arms 47 on a rock-shaft 42 provided with an arm 43, Fig, 5, engaging a bellcrank 44 which is connected by a link 46<a> to the dog 40b. Space-key actions.-The space-key 51, Fig. 2, is carried by arms 52 which are pivoted on studs 53 and have pins 55 engaging the arms 47 that carry the universal bail 49. Tabulating-mechanism.-A tabulating-stop 73, Figs. 2 and 5, is pivoted on a block 74 on the type-carriage A and engages a lever 70 which is connected by a link 69 to a tabulating-key lever 66. Upon depression of the tabulating-key 65, the tabulating-stop is projected for co-operation with one of a series of stops 76 mounted on a bar 77 on the frame 12. The tabulating-stop is connected to a returning-spring 75. Carriage-releasing arrangements.-A key-lever 57, Figs. 2 and 5, for releasing the type-carriage A has pin-and-slot connection 81 with a link 59 engaging a lever 61 which is provided with a hook 64 co-operating with the escapement dog 40<a>. For releasing the type-carriage when the tabulating key is depressed, the tabulating key lever is connected by a link 78 to a lever 79 which engages a collar 80 on the link 59. Back-spacing mechanism.-A back-spacing keylever 83, Figs. 2 and 5, is connected by linkage 84, 85, 87, 88 to a back-spacing pawl co-operating with the escapement mechanism 40. Ink-ribbon mechanism.-The ink-ribbon spools 112,113, Figs. 2 and 7, are mounted accessibly at the front of the above-described type-carriage A, the ribbon 116 passing directly between the spools and all guides excepting a vibrator 117 being dispensed with. A small area only of the work is obscured, since the ribbon descends from the spools to the vibrator. The spools and vibrator are associated with the automatic feedreversal and colour-change devices described below. The spool shafts 93 extend rearwardly and have bevel-wheels 101 meshing with bevelwheels 99, 100 mounted loosely on a driving-shaft 97 and adapted to be alternatively coupled thereto by means comprising connected clutch-levers 102, 103. The shafts are mounted in bearings 94, 96 above the plate 16 of the type-carriage. Feelers 110, 111 engaging the ribbon are secured to spring-urged rock-shafts 109 having cranks 108 engaging pins 107 on bell-cranks 106 which are formed with cams 104, 105 for engaging the clutch-levers. When the ribbon is becoming exhausted from either spool, the associated cam 104 or 105 is positioned to engage its clutchlever 102 or 103. and thereafter the clutch-levers are moved and the feed is reversed. The vibrator 117 has guide-lugs 119 engaging the aligning- guide 36, and a guide-slot 121 engaging a screw 120 The vibrator engages a forked lever 122 connected by a link 127 to a bell-crank 128 which is connected by a link 133, Fig. 22, to an arm 134 on the shaft 42 of the universal-bar mechanism. The link has a pin 132 engaging a slot 131 in the bell-crank, and a slot 143 in a slide 141 movable in a stationary guide 142. The slide engages a bell-crank 138 connected to a ribbon-key lever 136 by a link 137. On depression of the ribbon-key the pin 132 is moved towards the pivot 129 of the bell-crank and the throw of the vibrator is increased to render effective the red stripe of the ribbon. A pivoted locking-catch is provided for the ribbon-key lever.