Patent GB-727100-A (GB)
Abstract: 727,100. Calculating-apparatus. FELT & TARRANT MANUFACTURING CO. April 9, 1953 [May 16, 1952], No. 9649/53. Class 106 (1). In a calculating-machine provided with error control mechanism for locking the amount keys upon mis-manipulation (incomplete depression) of a key, the error control mechanism is adapted then also to prevent zeroizing of the accumulator. The invention has primary application in a machine with a split accumulator enabling the operator to transfer sub-totals, accumulated in the lower half, to the upper half and then to clear the lower half. Known mechanism locks the amount keys in the event of mismanipulating of a key, and the invention extends the action of this mechanism, when the accumulator is conditioned for split operation, also to lock the zeroizing lever, so that the operator is made aware of faulty key action in transferring a subtotal when he attempts to operate the zeroizing lever immediately following the transfer. The machine shown is of known key-responsive type comprising, for each column of amount keys 25 (Fig. 2), a parallel-motion linkage, the upper keyoperated bar 41 of which carries a dog 59 adapted to engage a hook 51 with a toothed wheel 62 on a motor-driven shaft 27, and the hook then drawing a link 52 rearwardly to lower a sector 29. Movement of the sector is restricted differentially by engagement of a connected stop-bar 55 with the stem of a depressed key and return movement under spring action is transmitted to the corresponding accumulator wheel 38 through a uni-direction train of gears including the pinions 31 and 36. A forwardly-biased latch 58 on thelowerparallel-motion bar 47 engages over the dog 59 to hold it lowered, and is not released until, by full key depression, the hook 51 is engaged with and driven by the wheel 62; a pin 63 moving with the link 52 then trips the latch to permit return of the parallel-motion linkage. The known mechanism for locking the amount keys, in the event of a partial key stroke, comprises a set of spring-actuated stops 152 (Fig. 2), adapted to engage under and lock the upper parallelmotion bars 41, but normally held clear by arms 156 on a universal bar 157 held effective by a detent arm on a touch-off shaft 161. Upon release of a partially-depressed key, a dog 106 (Fig. 4) on its lower paralell-motion link 47 picks up a ratchet tooth 107 on a lever 108, thrusting a link 117 rearwardly. The link 117, through an arm 162 (Fig. 2), rocks the touch-off shaft 161 counter-clockwise, and this releases the stops 152 to block the bars 41, so preventing further key action except in the order concerned where the stop 152 abuts the end of bar 41. With a full key depression and during the ensuing power stroke, a lug 125 on the link 52 strikes the tail 124 of a bracket 111 carrying the lever 108, so lifting the lever and its tooth 107 clear of the dog 106 which is, therefore, ineffective to actuate the touch-off shaft 161 and set the stops 152. Zeroizing mechanism and split accumulator arrangements. Forward movement of a zeroizing lever 71 (Fig. 1), through linkage 73-77, rocks a transordinal shaft 78 clockwise, arms 81 (Fig. 2) on this shaft moving links 82 forwardly to detrain the gears connecting the driving pinions 31 with their numeral wheels 38, so permitting the latter to be zeroized by their transfer springs. Coacting with the pinions 36 of the upper numeral wheels are a series of detents 315 (Fig. 3) adapted to lock the upper wheels when the accumulator is in split operation and the lower half only is to be zeroized. The engaging springs 323 of these detents are normally relaxed (Fig. 2) but are tensioned (Fig. 3) when the zeroizing lever 71 is operated, this being effected by downward movement of a yoke 177 connected by linkage 176, 172 and 171 with the links 82 above mentioned. In normal operation of the machine, a shaft 311 blocks movement of the detents by their springs, so that the whole of the accumulator is zeroized when the zeroizing lever 71 is operated. The machine is set for split accumulator operation by depressing a key 306 and hooking it on to the shaft 311 to retain it depressed. An arm 309 on the shaft 311 bears on a shelf 308 formed in the stem of the key 306 so that, when the key is depressed, a spring 367 rocks the shaft 311 counterclockwise to present a flat to the detents 315 enabling their springs 323 to engage them with the pinions 36 so that the upper accumulator wheels are locked against movement when the zeroizing lever 71 is operated. For locking the zeroizing lever 71, in the event of faulty incomplete key action when the key 306 is operative, a link 131 (Fig. 1), supported by an arm 133 and connected with the zeroizing lever, bears a stud 132 adapted to be engaged by a detent 341 controlled by a rockable anglebar 347 supported by end pivots 351 and extending across the rear of the machine. This bar 347 has three positions. In its normal or inactive position (Fig. 1) an arm 356 at one end lies above a cam lug 345 on the detent 341 and a spring 346 is able to hold the detent clear of the stud 132 so that the zeroizing lever 71 is free for operation. Depression of the key 306 rocks the bar clockwise into its second or operable position (broken lines, Figs. 3 and 4), an arm 365 on shaft 311 releasing a lever 358 to its spring 364, and a claw 359 on the lever rocking the bar. In its operable position, the arm 356 of the bar lies below the cam lug 345 of the detent 341, and the detent remains clear of the stud 132 so that the zeroizing lever is still operable. However, in this second or operable position of the angle-bar 347, forwardlyextending arms 348 thereon are lowered (see broken-line position, Fig. 4) for engagement by lifter arms 368, provided in the higher orders and each adapted to be raised by the corresponding link 117 when faulty key action occurs. In that event, the lifter arm 368 in the order affected rises and rocks the angle-bar to an intermediate or operated position in which the arm 356 engages fully on the cam lug 345, so rocking the detent 341 into engagement with the stud 132 and locking the zeroizing lever 71 against operation. The lifter arm 368 is held raised by engagement of a hook 375 thereon over the associated stop-bar 55. Full depression of the mismanipulated key results in forward movement of the stop-bar, release of the hook, downward movement of the lifter arm 368 and return of the angle-bar 347 to its second position in which the zeroizing lever is released. The zeroizing lever can also be released by restoring the accumulator split key 306 and thereby returning the angle-bar 347 to its first position. The hooks 375 are simultaneously released by means of rockers 377 actuated by the angle-bar. The invention is applicable also to key-driven machines, e.g. the machine described in Specification 633,957.