Patent GB-207858-A (GB)
Abstract: 207,858. Friden, C. M. F. Sept. 4, 1922. Multiplying and dividing apparatus; keyboards; differential mechnism. - In a machine of the multiple bank, key set, and independently operated type for the four rules, the key board mechanism comprises a plurality of units of nine keys numbered 1-9 and the differential mechanism associated therewith which is similar to that described in Specification 185,852 comprises setting elements adjustablv mounted on a main shaft and positioned on depression of the keys, and a corresponding number of totalizer-actuating elements fixed on the shaft and having toothed members movable outwardly to engage differentially the intermediate gearwheels of the tctalizer. Means are provided for locking the setting elements during the operation of the main shaft, for releasing the setting elements at the end of one rotation of the main shaft or holding them in adjusted position during repeated revolutions, and for releasing the depressed keys after one or a plurality of revolutions. Each key section is formed by a top plate 9 and a guiding element 12 and has nine numeral keys 5 and an error key 6 normally held in the raised position by springs 14 and a spring controlled detent bar 15 co-operating with projections 17 on the keys to hold them in depressed position. The key stems 13 are disposed above a duplex lever consisting of a main lever 21 pivoted at its forward end to a tongue 22 and a lever 24 pivoted on a tongue 23 and connected by a pivot pin 234 to the main lever 21. The levers are offset so that the main portion of the lever 24 is aligned with the rear part of the lever 21. The stems of the keys numbered 1 - - 6 act directly on the lever 24 and those of the keys numbered 7-9 on the main lever 21. The rear end of each lever 21 is pin- and-slot connected to a bell-crank lever 26 pivoted on a shaft 25, the vertical arm 29 having a toothed sector 31 engaging a pinion 32 on a differential setting element 36, Fig. 3, loose on the main shaft 33. The element 36 is provided with a cam-race 48, 53, an arcuate toothed sector 61 for holding it in adjusted position, and an indicating plate 56, visible through an aperture in the casing. Associated with each element 36 is a totalizer actuating element 35 which is fixed to the main shaft and is provided with a slide 45 having nine teeth 46 and a pin 49 which engages the cam-race 48, 53. The teeth 46 are normally held in the retracted position and are projected during the rotation of the main shaft to bring the selected number into engagement with the intermediate gear wheel 76 of the totalizing-counter 72 mounted on a laterally movable carriage 71. The main shaft is rotatable in either direction from an initial position by means of a crank 38 normally held by a retractible pin 42 which engages a hollow boss 43. The shaft 33 is provided with additional wheels 37 carrying the usual transfer pins associated with the totalizing counter. The totalixing-counter which is of ordinary construction is provided with escapement latches 78 to prevent overthrow and with any usual form of zeroizing-mechanism which upon operation effects the release of the latches. To lock the setting elements 36 against rotation upon the movement of the crank 38 the toothed sectors 61 are engaged by fingers 62 mounted on a sleeve on a shaft 63 to which is also secured an arm 64, Fig. 8, engaging a cam 65 on the main shaft. To permit the elements 36 to retain their setting during successive rotations of the crank when performing multiplication and division an arm 66<1> on the sleeve to which the fingers are secured is prevented from falling to disengage the fingers by means of a disc 67 secured to a spring pressed rod 68, Fig. 5, which extends into the hollow boss 43 and is free to move when the crank is operated. The arm 66<1> normally lies at the side of the disc 67. Special control keys 151, 152, 153 marked " clear," " + ", " X ", respectively are provided which on depression raise all depressed numeral keys, set the machine for addition and subtraction, and restore the machine to condition for performing multiplication and division. The stem of the key 151 is arranged to rock a lever 157 provided with a cam face 158 in contact with a pivoted plate 155 disposed in front of lips 154 on the detent slides 15 which are moved therebv on depression of the key to release the numeral keys. Depression of the key 152 rocks a lever 165 pivoted on the post 156 and raises a projection 164 thereon to lift the free end 163 of a bar 162 into engaging position with respect to the plate 155. The bar 162 which is pivoted to a gear wheel on a shaft operated by the main shaft is rocked to release the keys at each rotation of the main shaft. The bar 165 is effective to release the differential setting elements 36 by means of an extension thereon engaging an angular stop 168 pivoted to the shaft 25 which is raised, on depression of the key 152, to prevent the lateral movement of the disc 67 and rod 68 which controls the withdrawal of the fingers 62. The key 152 is held depressed by means of a spring- pressed slide 159 and is released to allow tho parts to return to normal positions for perform. ing multiplication and division on depression of the key 153. Specifications 212,206 and 212,207 are referred' to.