Patent GB-190702254-A (GB)
Title: Improvements in Typewriters.
Filed: 1907-01-29
Granted: 1908-01-23
Abstract: 2254. Lake, H. H., [Imperial Writing Machine Co.]. Jan, 29. Typewriters.-Relates to (1) carriage supports, (2) the paper-feed pressure roller, (3) platen-shift mechanism, (4) shift-key lock, (5) margin stop mechanism, (6) escapement-feed and release mechanism, (7) line-spacing mechanism, (8) backspacing mechanism, and (9) tabulating-mechanism. (1) The carriage comprises a main frame formed by rails o, p, Figs. 2 and 47, and end pieces 56, 57, and a vibratory platen-shift frame s, t, and is supported on a frame-consisting of angular pieces h connected by bars j, k and detachably secured on the main frame b by latch screws. Raceways for antifriction balls 35, 36 are formed by the rails o,p, and by rails m, n secured to the bars j, k, the rails being disposed to the front and rear relatively to the centre of gravity of the carriage, so that the carriage tends to cant to the rear. A pair of balls is provided in each raceway, and the longitudinal movement of the balls is restricted by means of a movable cage arrested or moved by stops on the' rails m, n, o, p to rectify any displacement. The cage consist of a pair of arms connected by a crosspiece 38 and formed at the ends with square openings and transverse lugs to confine the balls. (2) The paper table 125, Fig. 2, is secured rigidly on bearings 126 carrying the paper-feed pressure roller 127, Fig. 35, and fixed on a shaft 128 fitted on tenons on screws 130. The beariogs 126 are supported by springs 131 connected to ratchet-wheels 132 loose on the shaft 128 and retained by pawls 133, so that either end of the roller 127 can be adjusted by rotation of the ratchet-wheel at that end, in order to obtain uniform feed of the paper. (3) The platen-shift frame s, t, Figs. 2 and 47, is pivoted to arms 5 provided on the usual bar 2 fitted with a balancing-spring 4 and ratchets 3. The platen 71 is guided vertically by means of flattened trunnions u, Fig. 35, projecting through vertical slots w in the end plates 56, 57. The bar, t is of channel section, and faces rearwardly to form a bearing-rail and dust guard for the trundle roll 15<a> of the shift mechanism. The trundle roll 15<a> is carried by a lever 19, Figs. 2 and 6, fast on a rockshaft 16 connected by a universal joint 14 to an arm 1400 of a rock-shaft 12 operated by shift-keys, 9, 10. The keys 9, 10 are pivoted on the shaft 12, and operate the shaft by contact with lugs 13b, 13<c> on an arm 13 fast on the shaft. The lever 19 is arrested in its upward movement by an adjustable stop 20, and two limits to the downward movement, corresponding to the keys 9, 10, are determined by an adjustable abutment 24 on the main frame and a movable stop 23, normally located over the abutment 24. The stop 23 is carried by a spring-returned lever 21 connected by a link 26 to the key 10. The spring 4 effects return of the arm 13 and key 9. A spring of less strength than the spring 4 connects the key 9 to the arm 13, and retains the key 9 in its raised position even when the arm 13 is depressed by the key 10. In order to facilitate assembly of the shift mechanism, the shaft 12 fits at one end in a bearing 451 and is bored at the other end to receive a tenon 452 on a removable shaft 301, extending through a bearing 450 and secured by a screw 450<a> ; the shaft 16 extends at one end through a bearing 472 and is mounted at the other end in a bushing 470 secured in a bearing by a screw 480. (4) The shift-key lock comprises a spring-retained sliding bar 900, Fig. 6, operated by a key 915, Fig. 2, and provided with a notched offset 905 to engage over shoulders corresponding to the keys 9, 10 on an adjustable bolt 910 on the arm 13. The lock is released by again touching the locked key. (5) The margin stop 1900, Figs. 2 and 17, and write-over margin stop 1901 are arranged in different angular positions on a rocking bar 1902 connected by a forked arm to a push-rod 1904 retained by a spring 1905. These stops are formed on sleeves adjustable along a rack on the bar 1902. (6) The universal bar 50, Fig. 2, is hold in normal position by means of a spring 61 connected at one end to one arm of a T-piece 60 on the universal bar, and at the other end to an adjusting-device in the form of a bell-crank lever 62 and screw 64. The other arm of the T-piece 60 extends into line with the loose escapement pawl 69<a>, Fig. 30, and is connected to this pawl by a spring 70, which returns the pawl to working position after displacement to either side. The escapement pawls 69a, 71 are arranged in separate recesses 74, 73 in an arm 72<a> on the universal bar, and co-operate with an escapement wheel 72, which holds the loose pawl in line with the fixed pawl. The pawl 71 is fixed by a screw 75. The pawl 69<a> is pivoted on a pin 76 and is provided with an adjustable stop. The escapement mechanism is arranged under the usual type guide-plate 82 for protection from dust &c. The escapement wheel 72 is mounted on a shaft 84 provided with a pinion 83 engaging with a rack 85 on the carriage. The rack 85 is carried by bellcrank levers 86 pivoted on the carriage and normally retained against the rail p by springs 88. A release key 69<a> is connected to one lever 86 by a bent lever formed with a cam-slot engaging a projection on the carriage. (7) The line-spacing pawl 103, Figs. 34 and 35, co-operating with the ratchetwheel 100 on the platen shaft, is pivoted on a bell-crank lever 107, and is normally held by a spring 109 out of engagement with the ratchetwheel 100 and in contact with an eccentric 108 adjustable to vary the spacing. The eccentric 108 is carried by a spring-retained spindle provided with a milled head 115 notched for engagement by a catch 119. A combined brake and locking-device for the ratchet-wheel 100 is provided in the form of a spring-pressed arm 110, pivoted on a stud 112 and carrying a locking-roller 113 and a pivoted throwout device 114 bearing against the ratchet-wheel. (8) Back-spacing mechanism is shown in Fig. 23. A bell-crank key-lever 300 is connected by a link 307 to a bell-crank lever 308, to which is pivoted a short arm 311 of an angular pawl having a long arm 310 extending parallel to the escapement rack 85. The pawl is supported upon a boss 312 provided with a stop-pin 313 engaging in a cam-slot in the pawl. The parts are returned by a spring 315 connected to the pawl. The key-lever 300 is bent at 302, 303, and both limbs 300,303 are pivoted on the shaft 301, Figs. 6, 17, and 23, which is provided with a groove 305 receiving a screw 306 in the piece 302. (9) Tabulating-mechanism is shown in Figs. 2 and 17. A stop 420 on the carriage co-operates with stops 412 carried by a notched bar 410 on arms 408, one of which is engaged in a notched end 403 of a pushbar 402 pivoted to a bell-crank key-lever 400 pivoted on the shaft 301. The stop 420 is in the form of a pivoted spring pawl, so that it moves beyond the stop 412 last engaged immediately it is released therefrom, leaving the carriage free to be moved to the next stop. A brake-head 417, carried on a rockshaft 416 connected by an arm 415 and link 1400 to the key-lever 400, co-operates with a brake rail 418 on the levers 86 carrying the rack 85, and effects carriage release. The key-lever 400 and connected parts are returned by a spring 1450 connecting the parts 402, 1400.