Arrangement for effecting the shifting from small to capital letters in power operated typewriters

摘要

1,016,183. Typewriters &c. SOC. DE MECANOGRAPHIE JOPY. Aug. 31, 1962 [Sept. 5, 1961], No. 33538/62. Heading B6F. Depression of a ease-shift key 35, Fig. 1, causes half a revolution of an eccentric 5, Fig. 3, which operates a member 6 connected by a bell-crank 4 to the type-segment 1 to effect case shift, the connection between the member 6 and the eccentric 5 being such that the member 6 is not driven by the eccentric during the final part of the segment movement which is effected by an over-centre spring 13. Upon release of the key 35, a further half-revolution of the eccentric 5 takes place to restore the type segment 1 to its original position. At the diametral ends of its points of maximum and minimum eccentricity, the eccentric 5 is formed with notches 18 joined by circular arcs, and the eye 19 of the member 6 is formed with similar notches 20 which are in line with the notches 18 at the positions of rest of the eccentric, e.g. at the lower case position, Fig. 3, but spaced therefrom as shown. Depression of the key 35 causes the eccentric 5 to rotate anticlockwise for half a revolution, during the first part of which the member 6 is moved and raises the segment 1 despite play between the eccentric and the eye, the spring 13 urging the member 6 against the eccentric. Near the end of the half revolution, however, the raised parts 21 adjacent to the notches 18 contact the inside of the eye 19 to effect a positive engagement thus slowing down the segment due to the harmonic motion of the member 6. Finally, the parts move into the position similar to that of Fig. 3 but spaced 180 degrees therefrom where there is play between the eye and the eccentric and the segment 1 moves to its final position under the action of spring 13 only. The second half revolution of the eccentric effects the return of the parts to their initial position in a similar manner. Rotation of the eccentric 5 is effected from a constantly rotating shaft 15 having fixed thereto a ratchet wheel 14. A cam disc 22 fixed to the eccentric 5 has pivoted thereto at 29 a pawl 28 with a tooth 24 for engaging the wheel 14. In the lower case position, Fig. 1, a hook 30 engages a pin 26 on the pawl 28 to hold the tooth 24 away from the wheel 14. The hook 30 is part of a lever 27 which when operated by the depression of the key 35 withdraws the hook so that the tooth 24 engages the wheel 14 so as to rotate the eccentric counterclockwise. After half a revolution and with the key 35 still depressed, the pin 26 engages a stop 31 on the lever 27 so as to effect disengagement of the tooth 24 and thus of the drive to the eccentric 5. Upon release of the key 35, the stop 31 moves to inoperative position and the hook 30 to operative position so that the second half-revolution of the eccentric 5 can take place. A leaf-spring 40 on the pawl 28 is adapted to engage the wheel 14 before the tooth 24 so that the connection of the pawl to the wheel is effected without shock. The cam disc 22 has two lobes which have spiral forms joined by steps 38 inclined to the radius. A pivoted spring-urged lever 39 rests against the cam disc 22 and its engagement with the steps 38 causes a small anticlockwise movement of tooth 24 relative to wheel 14 to facilitate disengagement, and also prevents reverse movement of the eccentric. The segment 1 has an abutment 17 which engages damping washers 11, 12 cushioning the movement of the segment as the abutment moves towards stop-nuts 9, 10.