Patent GB-303775-A (GB)
Title: Improvements in or relating to calculating machines
IPC: G06C11/04
Filed: 1927-09-08
Abstract: 303,775. Percy, H. Sept. 8, 1927. Adding and subtracting apparatus; with printing-mechanism.-A multiple-bank machine operated by the value keys is adapted to add on a visible counter and print the items while by operation of a zeroizing-handle the total may be printed and the machine cleared. Key operation. The keys of each bank give differential movements to a rotatable shaft 5 by means of a rack 10 and pinion 7, Figs. 1 and 6, and these movements are conveyed to the corresponding numeral wheel 100 through a train of gears 88 provided with a non-return pawl and a one-way ratchet drive. The shaft is locked against untoward movement by a full-stroke mechanism consisting of a pair of oppositelydirected ratchet-wheels 12, 13, engaged by pawls 14, 15 linked to sectors 23, 24 gearing with a pinion 22 on a shaft 16 rocked by an arm 17 oscillated by a pin 21 on the key. As the latter is depressed the sector 23 raises the pawl 15 to permit the movement and at the end of the down stroke the pawl is again allowed to engage owing to a cam 32 on the shaft 16 freeing a coupling- pawl in the sleeve 27 from the link 31 to let this descend. Moreover owing to a slotted link connection 34 the pawl 14 is lifted to permit the return stroke of the key, the consequent movement of the shaft 16 and sector 24 further lifting this pawl to permit the unimpeded ascent of the key. Item-printing. Each differential shaft 5 positions an item-type bar 37 by means of spur gearing 42, 43, bevel gears 45 and rack and pinion. Beneath the keys is a lever 53 adapted to operate a hammer 39 through an arm 52. To throw out the item-printing a rod 103 may be shifted to displace the spur wheel 43 and thus break the type-positioning train. The paper 40 is linespaced by the gearing shown in Fig. 1, and including a ratchet wheel 69 rocked by a lever 72 operated by the lever 53 through a bell-crank 79. A rod 176 may be depressed to disable the lever 53 and thus the impression and line-spacing mechanisms. Subtracting. Subtraction may be performed by the usual complementary method and in order to prevent undesired transfers to the higher denominations a rod 122 may be pressed in to rock the transfer bar 113, Fig. 3, to the rear to throw its transfer-effecting tooth 114 out of engagement with the ratchet-wheel 115. The bar 113 is normally operated at transfer by means of a cam 112 geared with the lower denomination train, while the ratchet wheel engages wheel 118 of the higher train. Total-printing and clearing mechanism. Geared with each numeral wheel 100 is a drum 124 containing spring-controlled radially-slidable typebars 127, Fig. 10. Loose on but clutch-connected to a shaft 138 is a frame 137 adapted normally to close an opening in a casing 125 surrounding the drum. When the shaft is rocked counter clockwise the type-bar adjacent the paper is free to be projected by its spring and is then urged against the paper by a lug 139 on the frame. To prevent the printing of unwanted zeros the clutchcouplings between the frames 137 and the shaft 138 may be disabled by means of finger-levers 143, Fig. 3. The rotation of the shaft is effected by operation of the clearing bar 145 forming part of a frame pivoted at 144, Fig. 4, and geared with a shaft 147 through a slidable pinion 146 helically grooved to engage a pin 150. As the frame is swung the shaft 147 is shifted axially so as, through pinions 162, to operate mutilated gears 163 rigid with the numeral wheels, the zero positions of the wheels being finally determined by arms supported by toothed quadrants 154 rocked by pinions 153 on the shaft 147. The shaft 138 is operated from these quadrants by means of one-way pawls 159, bell-cranks 157 and links 158. To disengage the transfer-mechanism during zeroizing, cams 169 on the quadrants rock a bar 173 having arms bearing on the transfer slides.