25,290. Fairweather, W., [Underwood Typewriter Co.]. Nov. 24. Typewriters.- A pneumatic strip-controlled attachment for operating a typewriter comprises plungers for striking the usual keys for characters, spacing, platen - shift, tabulating, and ribbon-field change; special means are provided for operating the usual carriage - returning and line - spacing lever. Two endless controlling-strips 'are employed, one for writing say the body of a letter, and the other for writing variable matter such as addresses and insets. The endless strips C, D, only one of which is in action at a time, pass respectively over tracker-boards 91, 9 and rolls 101, 401, the slack dropping into a box. The character &c. keys 52 of the typewriter are operated by striking - rods 50 each connected to a pneumatic 61, which is collapsed by the controlling-pneumatic shown in Fig. 6. The chambers 71 of the controlling-pneumatics are connected by a pipe 7 to a set of bellows 3, 4, which is driven by a connecting- rod 5 from a wheel 1 and constantly exhausts air from the chambers 71. The operative strip in passing over its tracker-board periodically opens up communication between the atmosphere and the chamber 8 of the selected pneumatic, lifting the diaphragm 82 and thereby closing the aperture 85 by the valve 84 and opening the aperture 88 by the valve 86. Atmospheric air then passes through the pipe 89 to the chamber 8, thereby lifting the diaphragm 72 closing the aperture 79 by the valve 78 and opening the aperture 77 by the valve 76, thus connecting, through the pipe 75, the chamber 71 and the pneumatic 61, which is collapsed and operates its striking-rod. The paper-carriage is fed by the usual escapement controlled by the keys and is returned by mechanism of the following character. A screw 20, rotated constantly from the driving-wheel 1 by bevel-gear 11, 15, is caused to engage at therequired point in the line with a half-nut 21 provided with an arm 22 which is connected to the usual line-spacing and carriage-return lever. The nut is thrown in by a pneumatic 63, Fig. 4, controlled by perforations in the strips and connected by a bellcrank lever 64 to a plunger 66 adapted to engage the rod 68 of a pivoted frame 69 bearing on a pivoted sliding arm carrying the nut 21. When the plunger 66 is moved forwards, it rocks the frame 69 and throws in the nut 21, the frame releasing a spring bolt 900 formed with a shoulder 91, which engages behind the frame and locks it in the thrown - over position with the nut 21 in engagement with the returning-screw 20. The movement of the frame 69 is utilized to arrest the feed of the active strip C or D in the following manner. The roll 101 is driven by a pinion 102 on the same shaft as a disk 103 driven from the bevel-gear 15 by a friction roll 104, which may be shifted to vary the speed. The roll 401 is driven by a pinion 202 on the same shaft as a disk 203 belted to the disk 103. The frame 69 is connected by a link 94 to a bell-crank lever 96 engaging an arm carrying a pressure roll 30 and connected by a link 90 to a lever engaging an arm carrying a pressure roll 301. When the frame 69 is rocked, it lifts both pressure rolls 30, 301, and thereby arrests the operative strip C or D. The pneumatic 63 remains collapsed until the nut 21 reaches the spring bolt 900, which is pushed back and permits the frame 69 to swing to normal position, thereby disengaging the nut 21 and allowing the pressure rolls to drop back and re-start the feed of the operative strip. The means for controlling the typewriter by alternate action of the strips C, D are as follows. The pneumatics for striking the keys and the pneumatic for returning the carriage are all connected by pipes with Y-joints to both tracker-boards 9, 91, but there are two pneumatics each-connected only to one of the tracker-boards. These pneumatics engage on opposite sides of its pivot a rocking rod, which engages with its ends beneath the arms carrying the pressure rolls 30, 301. When it is necessary to change from one strip to the other, the perforation in the active strip, say C, comes over a duct in the tracker-board 91 and collapses the pneumatic for the rocking rod, thereby lifting the feed-roll 30 to arrest the strip C and dropping the feed-roll 301 to start the strip D.