Patent GB-302243-A (GB)
Title: Improvements in power operated shift mechanism for typewriting machines
IPC: B41J11/14
Filed: 1928-12-11
Abstract: 302,243. Royal Typewriter Co., Inc., (Assignees of Degener, G. 0.). Dec. 12, 1927, [Convention date]. Driving-mechanism; shift-key actions; platenshift mechanism.-A typewriter provided with the usual platen-shift frame is provided with a spring to move the frame into the upper case position, a key-controlled latch to control such movement, and power-operated means for returning the shift frame to its lower position against the spring action. The invention is particularly applicable to the power-actuated machine described in Specification 303,109. A pivoted latch 9, Fig. 1, with a hook 10 at its upper end to engage a lug 11 on the shift frame A, normally holds the latter in its lower position, the release being effected by a key lever 1 with an upward extension 7 connected to the upper end of the latch by a link 8 The shift frame is normally urged to its upper position by a spring 12 connected between a portion 13 thereof and a member 14, the position of which can be adjusted. The latch 9 is pivoted on a fixed axis 23 upon which is also pivoted a latch 22 provided with a cut-out shoulder 24 adapted to engage beneath the shift-frame lug 11 when the frame is moved to its upper position. The lower end of the latch 22 is connected by a link 21 to a lever 18 pivoted at 19 to the arm 7 of the shiftkey lever, and a spring 20 connected between a lug on the arm 7 and the upper end of the lever 18 causes those members to possess a certain amount of common movement. During the first part of the depression of the shift key the hook 10 slides off the lug 11; subsequently the spring 20 is tensioned and the shoulder 24 of the latch 22 snaps under the lug 11 as the released shift frame is pulled upwardly. The reverse takes place on the return movement of the shift frame, the latch 22 being moved first to enable the power mechanism to return the platen to its lower position. During the upward movement of the shift frame an arm 28 thereon, Fig. 2 (not shown) engages and swings a lever linked to means for starting an electric motor, as described in the Specification referred to above. To co-operate with the means for returning the shift-frame a resilient plate 33 carried near the lower bend of the key lever 1 has a horizontal heel 34 which encloses a recess 32 in the key lever. A power-controlled actuating-lever 35 pivoted at 36 to a lug on a transverse frame-bar 27 is urged upwardly by a spring 37 connected to a plate 26 on the bar 27, a projection 38 on the lever forming a stop to limit its upward movement. The connection between the lever 35 and the shift frame comprises a link 40 connecting an offset arm 39 on the lever to the arm 41 of a bell-crank pivoted on the machine frame, the other arm 41<1> of the bell-crank being connected by a spring 45 to a lug 46 on the link a of the shift frame and guided between the flat body of the link and a lug 43 offset therefrom. The spring 45 is made stronger than the spring 12, so that when the actuating lever 35 is moved anti-clockwise the pull upon the link 40 returns the shift frame to lower position, the movement being also cushioned by the spring 45. When the key lever 1 is depressed for case-shift an offset extension 54 on the lever 35 engages a part 55 of the underside of the key lever and, on the return movement of the key lever, engages the edge of the resilient part 34, which thereupon flexes, allowing the extension 54 to enter the recess 32 and causing the rear end of the lever 35 to drop. This causes a star-wheel 47 pivoted at the rear end of the lever 35 to be engaged by one of the fingers 52 on a motor-driven shaft 51, described in the Specification referred to above, the star-wheel being held against the lever by a spring plate 49 which causes them to be moved together. An upward movement of the rear end of lever 35 thus follows, and the shift frame is pulled to its lower position; this movement also withdraws the front end of the lever from the recess 32, and the parts return to normal position.