Patent GB-729820-A (GB)
Abstract: 729,820. Calculating-apparatus; zeroizing mechanism. FELT & TARRANT MANUFACTURING CO. Jan. 29, 1952, No. 2386/52. Class 106 (1). A calculating-machine with a multi-denominational accumulator having numeral wheel gears that are separable from their actuators to allow associated springs to return the numeral wheels to their zero position, comprises additional means movable from an inoperative to an operative position whereby the numeral wheels of certain denominational orders are then prevented from returning to their zero position when the numeral wheel gears are separated from their actuators. General structure. The various parts of the calculating-machine, Fig. 5, are housed in a frame mounted on a base 21 and supported therein by side-plates 22, with intermediate plates 23, Fig. 3, disposed between the various mechanisms of. the several denominational orders of the machine. Nine digit keys 25, Fig. 5, are provided in each column of the machine at the forward end of which the accumulator mechanism is mounted. The keys 25 actuate the numeral wheel 38 in the associated denominational order through their stems 27 co-operating with a column actuator 26 in each denominational order. Accumulator mechanism. Each numeral wheel driving gear train in the accumulator mechanism includes a spring winding gear 32, Fig. 7, normally in mesh with a transmitting gear 31 actuated by a rack 28 on the associated actuator 26. Each gear 32 drives a numeral wheel gear 36 through an intermediate gear 34. Each numeral wheel gear 36 is thus operable by its associated keys 25. A numeral wheel 38, Figs. 5 and 7, is secured to each numeral wheel gear 36. Zeroizing-mechanism. The spring winding gears 32 are on a shaft 33 in a frame 64 that is pivotally mounted on a transverse shaft 35, Fig. 6, the spring winding gears 32 being thereby disengageable from the transmitting gears 31, to allow the numeral wheels to be returned to zero by the spring-tensioned gears 32. Such detraining movement of the swinging frame is accomplished by forward movement of a zeroizing lever 71, Fig. 5, linked to the swinging frame, the frame remaining in its displaced position following the release of the zeroizing handle 71 until a digit key 25 is subsequently actuated. Preventing zeroizing of selected numeral wheels. The calculating-machine, has means selectively operable to prevent clearing of some of the numeral wheels 38 upon operation of the zeroizing handle 71, the other numeral wheels being returned to zero position. This means includes a zeroizing control key 201, Figs. 5 and 9, coupled through linkages with a flatted shaft 211 extending across the front of the machine. The key 201 is normally held in an upper position, Fig. 5, by a spring 203 coupled to a pin 204 on the side plate 22. The pin 204 normally engages a lip 205 on the key 201 as shown in Fig. 5 to limit the upward movement of the key. A number of detent levers 215, Figs. 3, 5 and 7, are mounted on a shaft 24 parallel with the flatted control shaft 211, there being a detent lever 215 for each of the numeral wheel gears 36 that may be lockable as a whole against rotation when the remainder of the machine is zeroized. With each detent lever 215 is a spring 221 urging the detent lever against the control shaft 211. With the control key 201 in its upper inoperative position, the flatted shaft 211 is in the position shown in Fig. 7 so that the detent levers 215 are urged forwardly by their springs 221. Each detent lever 215 has a rearwardly-extending finger 222 adapted, when the flatted shaft 211 is in the position shown in Fig. 7, to engage the teeth of the corresponding numeral wheel gear 32 when this is swung forwardly on the frame 64 on operation of the zeroizing lever 71. As a result, only those numeral wheels 38 that are not associated with detent levers 215 are zeroized on operating the lever 71. When the control key 201 is depressed, the pin 204 maintains the control key 201 in its depressed position by engaging in a recess 207 in the key 201, as shown in Fig. 9. On depressing the control key 201, the flatted shaft 211 is rotated in a manner turning its flatted surface 223 away from the detent levers 215 so that these levers are cammed forwardly to the position shown by broken lines in Fig. 7. If the zeroizing lever 71 is now operated the numeral wheel gears, on swinging forward on their frames 64, fail to be engaged by the fingers 222 of the detent levers and as a result all the numeral wheels are now zeroized. Indicating denominational orders that will not be cleared on operation of zeroizing lever. Bars are mounted on the keyboard between any two adjacent columns of digit keys 25 to indicate the lines of division within the accumulator occasioned by the provision of detent levers 215 in some of the denominational orders thereof. Specifications 556,239, 633,957 and 640,347 are referred to.