Patent GB-190108823-A (GB)
Title: Improvements relating to Typewriters
Inventor: HAMMOND JAMES B
Filed: 1901-04-29
Granted: 1902-04-29
Abstract: 8823. Hammond, J. B. April 29. Type-writers.-Relates to improvements in the Hammond machine, to adapt it for writing the Braille system for the blind, and for writing Arabic, Turkish, and other oriental languages as well as English. For this purpose the carriage is constructed to feed either from right to left or conversely, and the impression hammer, the shuttle, and the exposed characters on the keyboard, are all adapted to he readily changed. The shuttle a, Fig. 1, is of the usual form, and moves about a ring- shaped anvil b ; it is operated from the keyboard through a driving- lever k, and is controlled by a stop arm d and stop pins d'. The anvil is fixed to its post e, which is inserted loosely in the front standard f of a U-shaped frame, the rear standard of which serves as a support for the hammer. The anvil is prevented from turning by means of its crossarms h, Fig. 5, which rest against the ends of adjustable screws passing through extensions i of the post f. The screws guide the anvil when it is removed from or replaced in the machine, and also serve to support it against the blows of the hammer. For change of case, the anvil is lifted, carrying the type shuttle with it. This is effected by means of two shift keys s, the rear ends of which work in slots in bell-crank levers p. The upwardly-inclined arms of the bell-crank levers act as cam surfaces on an antifriction wheel mounted in the lower end of the anvil post e, and the cam surfaces end in hooks which positively grip and lock the antifriction wheel in the raised position. A shaft x can be rocked by means of the lever y so as to throw a stop-pin v into the path of the shift key. By this means a character can be raised to a limited extent when it is to be written as an exponent &c. The hammer z is carried by a horizontally-moving slide 1 guided at the top of the rear standard of the U shaped frame. The slide is operated by link and lever mechanism 4, 3, 5, from a lever 6 loose on the shaft of the escapement-wheel 8. The lever 6 has a depending pawl normally engaged with the escapement-wheel so as to hold down the rod 5 and keep the hammer in the retracted position. When a key is depressed, the space frame 19 is rocked on its shaft 20 so as to depress one end of a frame 22 and engage a detent pawl at its opposite end with the escapement-wheel. At the same time the pawl which depends from the lever 6 is released from the escapement-wheel, and the lever is rapidly thrown upwards by a spring, the hammer z being thus caused to strike. When the key is released, the carriage is fed forward, and the lever 6 is again drawn downwards, the hammer spring being thus tensioned for the next stroke. In adjusting the tension of the carriage-driving spring the hammer spring is also adjusted, for it is connected to a rack-bar provided with a gear connection with the shaft of the spring drum. A stop mechanism is provided to limit the movement of the winding-mechanism in either direction. In Fig. 2, the [machine is shown in plan view with the carriage and other parts omitted. The toothed wheel 42, Figs. 1, 2, and 16, which engages with the carriage rack 48, is made of large diameter in order to secure a powerful leverage on the pawl carried by the lever 6. The hammer z is designed to give a short pressing stroke rather than a swinging blow. It is of turret form, as shown in Figs. 7 and 8, being provided with a hard metal face 26 for manifolding, another 28 for mimeograph or stencil work, and another 27 pitted for Braille writing The remaining faces are covered by a rubber band 29 provided with a slot or opening for the faces 26, 27, 28. The band may be of different thicknesses opposite the various faces. A spring detent 31 holds the hammer in the selected position. In order to prevent the hammer from striking when the space-key is depressed, a slide rod 33 is projected over the end of the lever 6 by means of a bell-crank lever 34. The hammer spring is thus prevented from acting. The paper carriage 36 is driven from the main spring drum by a cord &c. which passes up between a pair of guiding-pulleys at the centre of the machine, and is attached to a clip which can be secured to the carriage at either end. The carriage can thus be driven in either direction by the same drum. The same escapement mechanism is made to serve for both directions of movement For this purpose a change gear mechanism is interposed between the escapement-wheel 8 and the carriage rack. The gear-wheel 42, which normally engages with the carriage rack, is adapted to slide on its shaft 7, Figs. 2 and 16, while always preserving its connection with the ratchet and pawl device 44, 45 which connects it with the escapement-wheel. The gear-wheel 42 is always in mesh with another sliding gear-wheel 47, and by means of a lever 52 the gear 42 can be withdraws from the rack and the gear 47 substituted for it, thus maintaining the escapement motion unchanged with a reverse movement of the carriage. A disengaging-sleeve 54 of the form usually employed in the Hammond machine is actuated by means of a suitable rod or lever to release the carriage from the escapement control, irrespective of its direction of movement. Back-spacing can be effected by means of a key 64, which actuates a pawl engaging with a ratchet-wheel on the shaft of a wide pinion placed beneath and constantly engaging with the gear 42. The pawl only engages with the ratchet-wheel when the key is depressed. In order to enable the widch of a letter space to be varied, the carriage is capable of a limited movement relatively to the rack-bar. The movement is effected by means of a shaft 69, Fig. 1, extending from end to end of the carriage and provided with short screws on worms near its ends. The shaft is turned, when required, by means of suitable buttons. For Braille printing the pitted face of the hammer is brought to the front, and a shuttle provided with indenting. points is used. The paper is turned face rearwards, and the carriage caused to feed from left to right. A pivoted carriage scale 79 is provided for the use of the blind, and also a pointer 74, Fig. 5, to which is pivoted an erasing-shield 78. The pointer can be swung aside on the anvil post e, and is held in its operative position by a spring catch 76. The erasing-plate 86 is carried by pivoted arms 80. Fingers 83 carried by a shaft 84 hold the paper or card to be printed against the edge of the erasing- plate 86. The fingers are pressed against the plate by means of a finger lever 88, the end of which works in a cam slot 87. The paper roller 96 is carried by downwardly-directed arms pivoted to the carriage frame. The line-spacing mechanism comprises a ratchet-wheel on the right-hand end of the platen adapted to be engaged by a pawl which is normally disengaged therefrom. The pawl is actuated by a pivoted and slotted plate engaged by the line-spacing lever, and its movement is limited by an adjustable stop. At the other end of the platen is a ratchet-wheel engaged by a spring-pressed detent roller. The keys are made adjustable so that different faces are exposed according to the nature of the work to be done. Fig. 26 shows the construction of a box-shaped key 114 supported by a two-armed frame 116, which is bolted to the key lever by means of a split stem 117. A slight projection from the box engages a recess in the frame 116, so as to prevent accidental turning of the box. Fig. 27 shows a key consisting of a metal plate 122 covered with rubber. It has two faces, and is sprung into place in the supporting-arms 126. The plate 122 may be cut out in the centre, so as to give an elastic touch to the key. The two-armed frame 126 is itself sprung into place on the fixed post 131. In the Provisional Specification a ribbon guide-plate and shield are described. In one form, the ribbon can be moved downwards to expose the printing point by depressing the space key ; in the other, it is raised to the printing point when a character key is depressed.