Patent GB-190117876-A (GB)
Title: Improvements in Typewriting Machines.
Inventor: MILLS BENJAMIN JOSEPH BARNARD
Filed: 1901-09-06
Granted: 1901-11-02
Abstract: 17,876. Mills, B. J. B., [Beam, W. de M.]. Sept. 6. Type-writers.-Relates to a type-bar machine in which nine types are carried by each bar. Fig. 2 shows the machine in side elevation, and Fig. 9 in rear elevation. The platen 12 is mounted in a carriage 9 guided in a bar 7 extending transversely of the machine. At its left-hand end, the bar 7 is secured to a plunger 5 adapted to move from front to rear in guides 2. At its right-hand end, the bar 7 rests freely on the flat surface of a lug 3 cast on the base of the machine. The plunger 5 is tensioned towards the front by a spring 6, but can be shifted rearwardly (carrying the platen with it), by means of a shift key lever 20, which has a pin-and-slot connection with the plunger. A depending finger 24 of the double-headed key 23 abuts against one or other of the stops 25, 26 according to which head is struck, and the platen can thus be shifted rearwardly so as to bring either the central gronp of three types 29, or the rearmost group of three, into action. The carriage 9 is drawn to the left by a flexible strap passing over a spring drum 18 loosely mounted on the plunger 5. The rear edge of the basebar of the carriage is formed as a feed-rack, some of the teeth 10 of which are exposed, as shown in Fig. 9, by cutting away the rear central portion of the bar 7. The type-bars 27 are pivoted to vertical arms 34 and the free ends of the bars are embraced by a yoke or guide 30 formed with an aligning- channel 31, Fig. 9. Fingers 32, secured to the type-bars, are guided in a comb 33, and assist in guiding the bars to the channel 31, and in returning them to the normal position. Offset plates 35, termed "fulcrum cams," are secured to the vertical vibrating arms 34, Figs. 2 and 5, which are pivoted on a common transverse rod 38, and are guided in slots formed in the plates 40, 41. There is one such arm and fulcrum cam to each group of three key levers 43. With each fulcrum cam are associated three slides 42, guided in the plates 40, 41, and formed with shoulders 42<1>, Fig. 5, adapted, when the slide is depressed, to engage with one of the converging cam surfaces 36 and enter the locking-notch 37, as shown in Fig. 6. The three key levers 43 in each group pass through slots in the three slides 42, and the depression of a key therefore actuates a slide, and locks the fulcrum cam in that one of its three positions which corresponds with the slide actuated. The fulcrum cam has no definite normal position, but remains in its previous position until shifted by the depression of another key. A bail 50 tensioned upwards by a spring 51 passes beneath each group of three key levers, and is connected by a link 49 to the typebar, which is thus brought to the impression-point when a key is depressed. The key levers are tensioned upwards by springs 47. The escapement device which controls the carriage feed is shown in Fig. 9. A bell-crank lever 52 is pivoted at 55 to the bar 7, and its shorter arm 52<a> is formed as a locking-pawl which is normally out of engagement with the rack 10. To the longer arm is loosely pivoted a pawl 54, which is adapted to move between stops 56, and is normally in engagement with the rack. As a type-bar approaches the impression-point, it strikes an arm 59 and depresses the arms 60, 52, so as to bring the pawl 52<a> into engagement with the rack, and release the pawl 54. The pawl 54 springs back under the tension of a spring 53, and re-engages with the rack in the next tooth when the type-bar returns from the impression point. The carriage-driving spring is then able to advance the carriage one step in the usual way. The pawl 54 yields to allow the rack teeth to slip over it when the carriage is returned to the starting point. The spacing-key 62, Fig. 2, actuates a rock-shaft 63 which carries at its rear end a finger 64, adapted to depress the arm 59 and thus operate the escapement mechanism. A release key 70, Fig. 9, is adapted to throw the pawl 54 laterally out of engagement with the carriage rack by means of a pivoted lever 69. The carriage is then free to move in either direction.