Patent GB-211966-A (GB)
Title: Improvements in or relating to power-operated typewriting machines
IPC: B41J7/02
Filed: 1922-11-30
Abstract: 211,966. Brougham, F. J., (Addograph Co.). Nov. 30, 1922. Relay type-lever actions; letter-spacing mechanism.-In power-operated type-lever machines of the kind described in Specification 25038/13, the letter-spacing mechanism is actuated by means connected to the type-lever actuator, a half-step of the feed being made on the forward stroke of the actuator and the remaining half-step on the return stroke. The type-lever actuator 41, Fig. 3, is similar to that described in Specification 210,894, comprising a curved bar adapted to swing forward under spring action when released and to be returned by an electric motor, which also drives a shaft geared to the lower end of a shaft 20 carrying a pinion 22 to feed the carriage in either direction, as described in Specification 211,954. The pinion shaft 20 has secured to it a notched wheel 24, Fig. 6, engaged by one of two pawls 27, 28, which are pivoted on arms 25, 26 loosely pivoted on, and radially projecting from, the shaft 20. Springs 29 connecting the ends of the pawls with the ends of arms 25, 26 tend to engage the pawls with the notched wheel. The arms 25, 26 are linked to a lug 35 at the rear of the type-lever actuator 41 through a pair of converging arms 30 connected to a lever 31, the connecting bolts 32 - - 34 being pivotal. The pawl 27 is normallv held in engagement with a notch in the wheel 24, the pawl 28 being held out of engagement by one of a pair of cam-lugs 56 on a plate 47 pivoted on the shaft 20. Upon the forward stroke, of the actuator the pawl 27 pushes the feed wheel 24 around until it is lifted out of engagement by its companion cam-lug 56, as shown in Fig. 6. The carriage has then moved half a step and in the meantime pawl 28 has slipped off its cam-lug 56 into the next succeeding notch in the wheel 24. The impression is made at the instantaneous stopping of the notched wheel. On the return stroke of the actuator the pawl 28 pushes the feed wheel the remaining half-step while pawl 27 makes an idle backward stroke. The pivot 32 on the arm 25 is normally held at the forward end of a slot 40 in the link 30 by a spring 39 connected between the lever 31 and the end of arm 25. The spring 39 is slightly extended at the commencement of the forward stroke and prevents straining and jarring of the levers. A spring 36 between the end of the lever 31 and the actuator cushions the return stroke. Back-spacing mechanism.-The rear end of the cam plate 47 on the shaft is connected by a transverse link 48 and a pivoted plate 49 to a link 51 which is pivoted at its lower end to the backspace key-lever 53. Depression of the back-space key 55 reverses the relative positions of the camlugs 56 and the pawls 27, 28, by raising pawl 27 out of engagement with the wheel 24 and positioning pawl 28 to push the wheel around on the forward swing of the type-lever actuator 41. The back-space key-lever 53 and the space-key levers 63 are so arranged that when lever 55 is depressed it strikes a laterally projecting lug 82 on one of the space-key levers 63 and depresses that also. Space-key actions. - The space-key levers 63, Fig. 3, operate the release bar 46 by raising a cam hook 61 to bear against it, the end of the hook being met by the actuator as it swings forward. The cam hook is mounted on a pivot carried by a piston which slides within a dash-pot 68 secured to the frame, a spring 80 normally holding the hook out of the operative position and holding the piston at the bottom of the dash-pot. The forward swing of the actuator is retarded by the dash-pot which introduces a load to correspond as nearly as possible with a working stroke when a type-lever is actuated.