Patent GB-190200174-A (GB)
Title: Improvements in Typewriting Machines
Filed: 1902-01-02
Granted: 1902-05-15
Abstract: 174. Fisher, R. J., and Fisher Book Typewriter Co. Jan. 2. Type-writers.-Relates to improvements in typewriters, applicable more particularly to the Fisher book type-writing machine. The type-carriage 3, Fig. 2, runs on the transverse rails 48, 49, which can be moved to and fro on the main track rails 50 by means of the usual line-spacing mechanism 53. Fig. 6 shows the carriage in horizontal sectional view. The carriage body is dropped between the rails 48, 49 so as to bring the rock-shafts 13 of the type-bars 14 as near as possible to the writing plane. At the rear side of the carriage is a reentrant crescent-shaped type-basket opening 6, the rearwardly-striking type-bars being thus arranged below, and clear of, the line of writing. The opening 6 is bounded by a curved plate 7, drilled with numerous holes so as to constitute a single bearing- member for all the rock-shafts 13. Fig. 8 shows a complete type-bar, rook-shaft, and key stem. The type-bars are welded to, or otherwise formed integral with, the rock-shafts, which carry at their other ends cranks 18 pivoted to the key stems 15. Coiled springs 20 return the type-bars to their positions in the basket when the keys are released. The front bearing-brackets 22 of the rock-shafts are secured to the floor 2 of the type-carriage. The type-bars are secured obliquely to the rock-shafts, with the result that they incline outwards or towards the rear in the basket, and leave a V-shaped opening in front through which the line of writing is visible. In order to preside for the crossing of the rock-shafts and for the accommodation of a large number of bearings in the plate 7, the rock-shafts are arranged in four distinct horizontal planes. All the shafts intersect the plate 7 at the same angle. Pivoted at the ends of the type-bars are the type-blocks 25, each of which bears two types 24, disposed at an angle to one another. A trigger or latch 27, engaging behind the heel 26 of the type-block, normally holds the upper type in the printing position. When, however, the latch is released by downward pressure on the finger 27<a>, the type-block flies upwards under centrifugal force when struck, and the lower type makes the impression. The latches are released by the downward movement of a segmental trip-bar 28, Fig. 2, which works in guide-slots in the supporting- brackets of the cushion or rest-ring 31. The tripbar is lowered to reach the latches by depressing the ‹‹ Cap " key 47, thus actuating the levers 44, 37, and depressing the sleeves 32 which carry the tripbar. The transverse rails 48, 49 on which the typecarriage moves are provided with plain tracks on which run the wheels of the carriage, and also with racks to receive pinions 57 (shown in the fragmentary plan view, Fig. 7), mounted at the ends of a shaft 58, controlled by the carriage feed escapement mechanism. At the extreme righthand end of each track 48, 49 is mounted a spring drum 64<a> connected by suitable tapes or bands to the type-carriage. The escapement mechanism is of the following character :-The shaft 58 bears a double-crown escapement-wheel 65 with which co-operate the dogs 67, 68, disposed in scissors-like fashion about a common pivot 70. The shoulders of the scissors joint are such that a limited relative play of the dogs is allowed. When the dog 67 moves forward into engagement with the escapement-wheel, the dog 68 disengages from it, and conversely, but the dog 68 can be disengaged from the wheel by means of the carriage releasekey without moving the dog 67, the carriage being then free to move in either direction. The movements of the dog 67 are effected by means of a reciprocating bar 81 actuated by arms depending from the rock-shafts 88 of universal bars 86. The bars 86 are depressed by pins 85, Fig. 8, projecting from the key-stems 15. The space-bar 91, Fig. 2, actuates the front universal bar 86. The inking- ribbon 100 extends transversely across the typebasket opening 6, and is designed to wind and unwind upon spools 101, Fig. 2, slidably mounted or feathered on spindles 102 journalled in bearings 103 on the type-carriage. Each spool is embraced by a shifting yoke, also sliding on the spindle 102, and terminating in a curved ribbon guide 105. The ribbon guides are supported on tracks 107 by means of wheels 106, and the complete system of spools, guides, and ribbon can be shifted by means of bars 108, levers 109, 113, and key 115, so as to expose the line being written. Loosely mounted on the spindles 102 are pinions 117 meshing with the rack on the bar 49. One or other of the pinions is always in engagement with the ratchetwheel 118 on the corresponding spindle 102, by means of a pawl 119, and the reversal of the ribbon is effected by the movement of a pivoted bar which throws one of the bevelled release discs 121 forwards so as to disengage the corresponding pawl 119 from its ratchet-wheel, and throws the other disc back so as to allow the other pawl to re-engage.