GB154087A - Improvements in typewriting machines - Google Patents

Abstract

154,087. Fairweather, W. C., (Underwood Typewriter Co.). Dec. 29, 1919. Carriage-shift mechanism; shift-key actions.- A carriage-shift mechanism of the double-shift type comprises a sheet-metal shift frame having turned-over edges 36, 71, Fig. 1, for co-operation with three pairs of adjustable stops, one pair 70 for the normal position, another pair 37 for the single-shift position, and a third pair 57 for the double-shift position, the second pair 37 being normally in effective position and being swung aside to render the third pair effective when the double-shift key 30 is depressed. The shift frame is detachable, the upper guide links 21 being attached to the shift frame by pivot screws 20, the lower guide links 24 on a rock-shaft 27 being provided with stub-shafts 25 loosely engaged by yokes 26 on the shift frame, and the stops 57, 70 being carried by brackets 58 detachably secured to the main frame by screws 59. The shift-key levers have extensions 33,. 56 underlying an elbowed end 34 of a rock-arm 35 fast on the shaft 27. The single-shift stops 37 are carried by arms 39 forming part of a pivoted bail 62, which is held by a spring 65 so that the stops 37 are normally effective, and is swung aside by engagement of a lateral projection 69 on the double-shift key-lever against a bracket 67 attached to the bail. The single-shift key-lever is returned by a spring 73. Projections 75, 77 on the shift-key levers engage against the transverse member 54a of the main frame to limit the return movement under the action of the springs 65, 73. Key locks.-The shift-key levers are provided with pins 44, 69<a>, Fig. 2, for engagement by locking-arms 43, 54 on a rock-shaft 48 operable by a key 46. One arm 54 is provided with a pin 53 engaged by a spring 52 to return the parts. The ends of the arms engaging-over the pins are so shaped that a slight depression of the locked key is sufficient to allow the spring 52 to become effective and withdraw the arms. The front edges 78 of the arms are shaped for engagement by the pins on the shift-key levers so that depression of either key-lever withdraws the lock from the other.