Patent GB-190408976-A (GB)
Title: Improvements in Adding and Subtracting Mechanism adapted for use with Typewriters
Inventor: MARTIN JOSEPH HARRY
Filed: 1904-04-19
Granted: 1905-03-16
Abstract: 8976. Martin, J. H. April 19. Calculating- apparatus ; counting - apparatus. - Keyboard adding and subtracting machines in which one group of ten keys is employed, the item wheels moving automatically upon a carriage as the digits of successive orders are depressed, are shown in Figs. 1, 2, and 4. The totalizing - wheels are capable of two positions, one for addition, the other for subtraction, and are moved by a lever into gear with the set item wheels, which are then released to operate the totalizing- wheels. The items, sums, and differences are also printed, and the machine is so designed that its keys may be coupled to the numeral keys of a type-writer. When one of the keys 1 shown in the plan view, Fig. 1, and side elevation, Fig. 2, is depressed, the pin 22 thereon depresses the setting-bar 3,which is carried by arms 5 on the shaft 7, and carries down with it the forks 21, roller 20, and U-shaped frame 18, pivoted on studs 17 concentric with the spindle 10, mounted in posts 11 upon the carriage 8, which can slide transversely in the guides 12. Loose upon this spindle are the item wheels 9, each having a circumference divided into toothed and type-bearing segments 13, 9<1>, and normally held by a ratchet 23, but rotated by the spring pawl 19 on the frame 18 when a key is depressed, the extent of the motion being determined by the position of the pin on the key rod. Previously to this, the foot of the key has depressed the spacing-bar 4, held by arms 6 also journalled in the rear shaft, and by means of the linkwork 31, 30 has forced the lever 29 to move transversely across the machine and to allow a pin at its extremity to move one tooth along the rack-bar 28 attached to the carriage, so that, on the return of the parts effected by the spring 27, the rack-bar and carriage will be moved transversely by that amount against the tension of spring 107, and held in position by the detent lever 34, spring-pivoted at 105. Over-running of the item wheels is prevented by a projecting finger 35 on the spacing-bar, which, at the end of the down-stroke, rocks the lever 36 and brings its extremity 38 into engagement with the item wheel. The bar 83 is next operated to put the item on to the totalizer, the first step being to draw the bar 86, and the totalizing-carriage 39 with which it is spring-connected, horizontally forward in the guide-posts 40 until the total wheels 45 or the subtracting wheels 49', Fig. 4, are in gear with the item wheels. Upon the carriage are posts 43 with a cross spindle 44<1> for two U-shaped frames, an upper one 57, and a lower carrying on a spindle 46 the subtracting wheels 49<1>, which gear with and resemble the total wheels on the spindle 44<1> in being formed of a disc, with numerals to be read through the slot 56 in the upper frame, and a toothed wheel, fixed together. 13y means of the detent 48 and handle 77, both hinged to the lower frame on the rod 52, the wheels can be rotated about the upper spindle into either of the two positions defined by the projection 76 and recesses 78, 79, corresponding to subtraction and addition respectively. The carriage moves forward until engagement with the item wheels occurs, when the end of the bar 86 leaves it, and allows the tooth 91, Fig. 6, to snap in under the pressure of the spring 93', whereupon the detent 92 locks in one of the slots 94, 95 according to the position of the handle 77. The final downward motion of the bar 83 then operates the rod 97 and swinging frame 98 to throw all the item-wheel detents out of gear and allow coiled springs to return these wheels to zero, simultaneously driving the wheels on the totalizing-carriage with which they are in gear, a pin 102 and stop 101 determining the zero position for each item wheel. Transferring on the total wheels is thus effected.-As the wheel moves from " 9 " to " 0 " a pin 55, Fig. 4, thereon presses back the arm 49, which is pivoted on the rod 52, and moves its arm 58 into such a position that the spring 62, normally in the notch 64, falls into the notch 63, and, as the carriage comes back owing to a spring return of the rod 86, a pinion 71 engages with the fixed rack-bar 42 and causes suitably-staggered fingers 72, 73, 74 upon its spindle to engage with the swells of the levers 49, restoring them to their normal forward position, the arm 58 feeding 'the next higher total wheel during the movement. Similar means are used for transferring on the subtracting wheels. During the return of the totalizing-carriage, the pin 103, lever 104, and bell-crank lever 34 co-operate to free the rack-bar 28 and to allow the item carriage to return, spring- controlled link work being provided to prevent the detent 34 again dropping into place until the carriage reaches its normal position. The printing- mechanism inks the type on the item wheels, takes an impression, and feeds the paper, motion being derived from the bar 83 and links 116, 113, 117. As the item wheels move round for setting, the types touch the inking-roller 126, which is swung horizontally by the descent of the rod 127 on the arm bearing the feed and impression rollers 119, 118, of which the latter now prints, the paper being fed on the return stroke by rotation of the ratchet-wheel 120 by the spring 121. All the keys are carried in a frame consisting of plates 122, 123, 124, which is hung from pins 129 in the posts 130, and it is thus possible, when the keys of the machine are coupled to or operated by those of a type-writer, for the whole of the adding-machine keys to be swung out of the operating-position when it is required to use the numeral keys of the typewriter without actuating the adding-mechanism.