Patent GB-191114816-A (GB)
Title: Improvements in Combined Adding and Typewriting Machines.
Inventor: FAIRWEATHER WALLACE CRANSTON
Filed: 1911-06-26
Granted: 1912-03-21
Abstract: 14,816. Fairweather, W. C., [Underwood Computing Machine Co.]. June 26. Adding-apparatus; attachments and connexions to typewriters. -A combined typewriting and adding machine of the type described in Specifications 6647/08, 8740/09, 8981/10, and 3281/11, in which the computing-mechanism is power - driven and operated by an escapement or differential mechanism under the control of the numeral keys, is provided with means whereby the computing- mechanism is disengaged from the typewriter numeral keys, the simultaneous depression of two keys is prevented, and complete depression of a key ensured before it is returned to its normal position. Keyboards; interlocking; differential mechanism.-The numeral keys 3 are connected to links 45 by means of bell-crank levers 39 and links 6. The links 6 pass through slots in a sliding bar 5, Fig. 2, which is adapted to slide longitudinally to disconnect the numeral keys from said links. The links 6 are hooked at their lower ends to engage jaws 8, 9, formed on the key - levers, which jaws are provided with extensions to ensure the action of the links. The sliding bar 5 is connected by means of a pin 11 thereon to a double-armed lever 13, the upper end of which engages a pin 18 on an arm of a four-armed lever 19. Upon the pin 18 a hub is mounted which carries a lever 24 and handle 25 adapted to engage a pin 35, thereby holding the four-armed lever in the position shown in Fig. 2. To effect the movement of the bar 5, a key 33<a> is depressed and, by means of a lever 33 actuated thereby, a link 32 is pulled down and the four-armed lever, to which the link is pivoted, is rocked. To disconnect the computing mechanism when the machine is typing capital letters, the platen frame 3<c>, Fig. 16, is connected by means of a lever 38 to a link 36 pivoted to the pin 35. The depression of a key 3 by means of the link 45 rocks a lever 46 which throws a corresponding segmental blade 75 into a slot 77, Fig. 14, in a fixed disk 52 so as to intercept any of the remaining blades thus ensuring that only one key shall be depressed at a time. At the same time the lever 46 thrusts an arm 50 through a slot in the disk 52 in order to project one of the stop pins 53 of the escapement-wheel 54 to the right into the path of a stop-wheel 55. The stop-wheel is mounted on a spindle 56 which is provided with a four-toothed escapement-wheel 57 engaging a disk or dog 58, which locks the stopwheel to prevent actuation of the escapement-wheel 54. The disk 58 is mounted on a spindle 59 adapted to be oscillated when a key is depressed by means of levers 60, 61, and 62; the lever 62 is engaged at one end by disks 65, 66 which are moved longitudinally by the lever 46. When the dog 58 is rocked the wheel 57 rotates until it is engaged by another disk or dog 116 and is held thereby until nearing the end of the return of the spindle 59, that is, when the key has nearly completed its return movement. the wheel 57 then escapes and frees the escapement-wheel 54 which rotates until the last projected pin is arrested by the stop-wheel 55. The key-levers are connected by means of bell-crank levers 103 to type-levers 104 which are adapted to strike against the platen 3<b> and press a universal-bar frame 107 rearwards to actuate the fast and loose dogs of the carriage escapement-wheel 111. The wheel III is attached to a pinion which engages a rack mounted on the paper carriage. To ensure the movement of the carriage before the actuation escapement-wheel 54 is freed, a latch 117 is provided to engage a notch in the arm 60. This latch is actuated through levers 122, 123, 124 by means of a pallet 121 engaging the teeth of the carriage escapement-wheel. Keyboard interlocks; full-stroke mechanism.- On the spindle 59 is mounted an arm 79, Fig. 9, operatively connected by a link 82 to a rod 84 which is pivoted to a bell crank lever 86 adapted to rock an arm 88 and thereby move a locking-bar 80 beneath the hooks 81 of the key levers 3. At the same time a latch 92 snaps into a notch 94 in the link 82 and holds the locking-bar in position. The bar is released near the end of an operation by means of an arm 95 adapted to be rocked by the escapementwheel 57. To prevent a key from returning to its normal position before being fully depressed, the bell-crank levers 39 are provided with toothed segments 40 with which engage spring-controlled pawls 41. Operating by motors.-The escapement-wheel 54 is under the control of a constantly rotating motor, which drives the computing-wheel spindle through a friction clutch and gearing, the transfer spindle being also constantly rotated by means of gearing which connects it directly to the motor. The clutch and gear-wheels are mounted in a closed box containing lubricating- oil or the like.