Patent GB-303188-A (GB)
Title: Improvements in power operated typewriting machines
IPC: B41J23/12
Filed: 1927-08-29
Abstract: 303,188. Degener, G. O., and Royal Typewriter Co., Inc. Aug. 29, 1927. Relay type-lever actions.-The type-levers are constantly urged towards the printing point by means such as springs or electromagnets and are in direct engagement with holding-means which on being released permit movement of the type-levers, power means being provided for returning the type-levers. The mechanism may be driven by a motor having controlling-means for maintaining the motor in operation so long as the interval between the return of one type-lever and operation of the next lies within a predetermined limit. In the machine shown in Fig. 1, each key-lever 3 is provided with pivoted arms 7, 8 which are drawn together by a spring 11 and have shoulders 17, 18 for engaging a lug 16 on the associated type-lever 12, the shoulder 18 being lower than the shoulder 17. A slot 19 in the heel of the type-lever engages a pin 21 on a sub-lever 22 connected by a link 24 to a bell-crank 28 which is urged forward by a spring 30, movement being prevented by engagement of the lug 16 with the shoulder 17. The group of springs 30 is connected to a plate 31 on a shaft 32 which can be turned to adjust the tension of the springs by means of a knob having a worm engaging a worm-wheel 33 on the shaft. The bell-cranks are provided with rotary cams 43 for engaging a friction-surface on a shaft 44 driven by an electromotor G. The shaft is geared to a centrifugal governor 60. The depression of a key lever releases the lug 16 from the shoulder 17, and the spring 30 is permitted to swing the type-lever until it approaches the printing point. The cam then engages the shaft and arrests the sub-lever and bell-crank, an enlargement 20 of the slot 19 permitting the type-lever to move independently of the sub-lever and complete the impression movement by momentum. The cam on engaging the shaft is rotated to return the type-lever and sub-lever, and re-tension the spring 30. Overthrow of the cam is prevented by a spring blade 52. If the key-lever has not been released, the lug 16 is caught by the shoulder 18, and on release of the key-lever, the lug is released from the shoulder 18 and caught by the shoulder 17. To prevent clashing of the type-levers, an interlock, described below, is provided for the key-levers, and arms 40 on the key-levers co-operate with arms 41 on the sub-levers to prevent return of the operative key-lever until the type-lever has performed a substantial return movement. The links 24 have projections 53 for operating a universal bar 54. The electromotor is controlled by the switch shown in Figs. 8, 10 and 11 and constructed in the following manner :-The shaft 44 is coupled by a cross-pin 83 to one end of a worm-shaft 82 which is mounted at the other end in a rocking arm 88 and co-operates with a worm-wheel 71. The arm 88 is secured to a rock-shaft 89 provided with an arm 96 having pin-and-slot connection with a link 99 connected to the universal bar 54. A spring-urged member 64 pivoted on a stud 63 is formed with a short arm 65 carrying an insulated contact-spring 80, and a long arm 66 which normally abuts on a nose 76 on a spring-urged lever 72. The lever 72 engages a lever 92 which engages a lug on the arm 88. The arm 66 carries a spring-urged pivoted arm 112 having a tooth 115 in the path of a pin 116 on the worm-wheel. The motor leads are connected to a contact 78 on the spring 80. and a contact 102 on an insulated plate 101, the spring normally resting on an insulated block 105 on the plate. The plate is provided with curved contact-springs 107, 110 directed towards the back and front of the block. On operating any key-lever, the lever 88 is depressed thereby releasing the worm 82, and the lever 72 also is depressed thereby permitting the spring 80 to move along the spring 107 to the position a Fig. 10, and close the circuit of the motor. During return of the type-lever. the lever 88 is lifted by a spring and causes the worm 82 to engage and turn the worm-wheel, so that the pin 116 co-operates with the tooth 115 and causes the spring 80 to move along the spring 110 to tho position c and maintain the circuit of the motor. Thereupon the pin 116 rides off the tooth 115 and the spring 80 returns into contact with the block 105 and opens the circuit of the motor. If, however, a second key-lever is depressed during the period of about three seconds required for the above-described movements of the spring 80, the worm is again depressed and the spring returns to the position a and closes the circuit of the motor. When the key-levers are rapidly operated, the spring remains in the position a since the period of engagement of the worm is too short to produce an appreciable movement of the spring. Key interlocks. To prevent operation of more than one key-lever 3, Fig. 1, at a time, the keylevers are provided with lugs 50, Fig. 1, which co-operate with laterally movable balls or rollers 49 mounted in an opening 48 in a support 47.