Patent GB-190221008-A (GB)
Title: Improvements in Typewriting Machines.
Inventor: MILLS BENJAMIN JOSEPH BARNARD
Filed: 1902-09-26
Granted: 1903-02-05
Abstract: 21,008. Mills, B. J. B., [Adams, H. C.]. Sept. 26. Type-writers. - Re. lates to improvements in the construction of front-strike type-bar machines. The key levers 4 are pivoted on a fixed fulcrum rod 5, and their upstanding rear portions 7 are connected by links 8, Figs. 3 and 4, with the cranks 9, which serve to rock the type-bars 11 about their vertical shafts 10. For the cranks 9 may be substituted elongated pinions engaged by racks formed on the rear ends of the links 8. Fig. 1 shows the type-bars 11 of one half of the keyboard with their cover removed. The bars are of successively-increasing length from the innermost outwards, and each moves in a lower plane than the preceding one, as shown in Fig. 3. The blocks 12 on which the types are carried are all in the same plane, so as to strike at the common impression point. The shafts 10 are journalled in one vertical plane in a holder 25, Fig. 3, which can be raised and lowered for change of case, and for this purpose the cranks 9 are adapted to slide freely up and down in the apertures in the rear ends of the links 8, which are maintained in fixed planes by means of guide-bars 13. Springs 14 resist depression of the key levers, and their action is supplemented by coiled springs 59, Fig. 4, which tend to draw back the type-bars from the impression point. Fig. 11 shows a modification in the form of the connecting-link 8, which is forked. There is lost motion at the point 79, so that the link 75 first transmits the key pressure at a considerable leverage, and the link 78 takes it up when the type-bar has been well accelerated. The holder 25 is raised or lowered for change of case by means of a three-armed lever 48, Fig. 3. A pin on the forwardly-pointing arm normally presses upwards against the rear end of one of the two shift-key levers. When this lever is depressed, the pin is able to rise, and the holder 25 falls. If the other shiftkey lever is depressed, a cam-surface 56 pushes back the pin 57, and the holder rises. The notch 55 limits its upward movement by locking the pin 57. Springs 52 balance part of the weight of the holder 25. A shift locking device is provided, consisting of a pivoted finger normally situated between the two closely-adjacent shift-key levers and adapted to be rocked over the depressed one so as to prevent it from rising. Each key lever is provided with a cam like portion 63 bearing against the back of a universal bar or plate 61 extending transversely of the machine. The spacebar frame 65 actuates the universal bar in the same manner. Arms 67, Fig. 5, connect the universal bar with a yoke or frame 68, which has a pin-andslot connection with an arm 71 depending from the escapement dog rocker 72. The dog rocker carries two pivoted dogs 105, 106, which co-operate with the carriage feed rack 115 in the usual manner. The dogs have rounded hubs, which are notched to engage with leaf springs, one of which extends partly round the hub. Both dogs yield to allow of the return movement of the carriage, and one of them is held by its controlling spring away from its limiting stop except when the said spring is opposed by the more powerful carriagedriving spring. A spring 76 resists movement of the escapement dog rocker. The main frame of the carriage is formed of a single piece of stamped sheet metal, which includes the feed-rack as well as the end plates, and is bent to the required form. The line - spacing mechanism is of the following character :-To the shaft 17 of the platen roller 16 is secured a ratchet-wheel 125, Fig. 20, and a line-spacing lever 126 bearing a gravity pawl 128 turns freely on the shaft. The rearward movement of the line-spacing lever when the thumb-piece 127 is pressed is limited by an adjustable stop 131, which can be engaged with any one of the holes 18<k> according to the line space required. A spring 135 returns the line-spacing lever after use, and a round-ended detent pawl 136 maintains the ratchet-wheel and platen in the newly-adjusted position. The paper is guided by a plate 110, Fig. 3, formed with spring fingers, in which the rubber-faced feed-roll 142 is journalled. Leaf springs 144 engage beneath the plate 140, and hold the roil 142 against the platen. The rear side of the carriage slides on a rail 19, and the front edge is provided with a roller 148, Fig. 5, which runs on a track 151. A cord or spring drum tensions the carriage towards the left in the usual way. The scale bar 157, Fig. 3, is carried by fingers 157<a> on a rock-shaft 158, and is spring- tensioned towards the platen. The keyboard is automatically locked in the following manner to prevent the over-running of a line :-A bell-crank lever 167 pivoted at 166 is provided with a hook 168 adapted to engage beneath the rearwardlypointing finger 169 of the escapement dog rocker and thus lock the escapement dogs, universal bar, and keyboard against further movement. The arm 171 is normally prevented from rising by the bail 172, against which it presses, but when the carriage has nearly reached the left-hand limit of its movement the arm 171 rises into a recess or cut-away portion of the bail 172, and the hook 168 locks the feed-mechanism. An auxiliary bail 175, Figs. 3 and 5, is mounted on the rock-shaft 173 and can be lifted by means of a finger plunger 225 and lever 176 (pivoted at 177) so as to depress the bail 172 and free the carriage for writing a few more characters. The bail 172 may be formed with an adjustable plate for varying the length of the cutaway portion referred to above. The bail 172 carries a rearwardly-projecting lug, which co-operates with an adjustable margin stop mounted on the machine frame, to determine the left-hand margin on the paper. By depressing the bail 172, the margin stop can be passed, and words can be written on the margin. A key is provided which lifts a detent having a limited sliding movement into engagement with the carriage rack. When this is done, the carriage can be pushed towards the right through one tooth only, and this enables the re-printing of a character imperfectly struck to be effected without special care in adjusting the carriage. Devices for facilitating the writing of tabular matter comprise finger plungers 225 placed at intervals behind the keyboard and serving to operate levers 228, which lift stop-bars 231 guided in bosses 232. An adjustable stop-lug 240, Fig. 5, depends from the paper carriage, and co-operates with the stop-bars 231. When a stop-bar is lifted, its upper end forms an abutment to stop the released carriage, the release being effected by a bail 234, Fig. 3, which is raised by the pin 233 and serves to lift the arm 78, Fig. 5, and rock the escapement dogs out of engagement with the carriage feed-rack. The inking-ribbon mechanism comprises two spools mounted loosely side by side on a short horizontal shaft, each being provided with a ratchet-wheel. A retaining-pawl engages each ratchet-wheel, and each is also adapted to be engaged by a gravity pawl pivoted to a rocking lever, which is linked to the yoke or frame 68, Fig. 5. A sliding bar, forced with wedge-like or cam surfaces, is adapted to lift either pair of pawls and put the other pair in action, reversal of the ribbon being effected by sliding this bar. The inking-ribbon extends upwards from the spools in a vertical plane, or passes through an oscillating yoke, which is thrown up against the platen at the moment of impression, being connected with the frame 68 for that purpose. To assist in aligning the type at the impression point, each type-block may bear a conical pin 12", Fig. 3, which enters a hole in a bar extending vertically upwards from the holder 25 which carries the type-bars. The bar also carries lugs 229, Fig. 1, between which the type strike.