Patent GB-826425-A (GB)
Abstract: 826,425. Calculating-apparatus. MARCHANT CALCULATORS Inc. March 19, 1957 [Oct. 22, 1956], No. 8961/57. Class 106 (1). A full keyboard calculating machine has ordinally arranged decimal-point keys, depression of any one of which sets a corresponding decimal point indicator for the register and causes the latter to be shifted to a corresponding denominational position. The invention is embodied in a machine basically similar to that described in U.S.A. Specification 2,271,240, for multiplying by repeated addition and having a product register mounted in a laterally movable carriage together with a revolution counter. The present machine has in addition a multiplier factor store and indicator settable under the control of the keyboard and a multiplicand indicator settable by the keyboard. On depression of an amount key 100, Figs. 1 and 2, a selection bar 120 is differentially moved and sets a corresponding (multiplicand) indicator drum 140 and " cams " 146 which during a main cycle of the machine are sensed to control the actuating mechanism for the corresponding product register wheel 279 in the carriage 250. The multiplier indicator drums 3000 are set during multiplication. Clearing product register and counter.-The product register is cleared by the operation of a special clutch, Fig. 3 (not shown), engaged by depression of a key 373 or, in certain circumstances, automatically. The control mechanism is restored after one cycle of the clutch even if the key is held depressed. A Lock key 3025 disables a coupling in the mechanism for automatically initiating a clearing operation. This key is held depressed until the key 373 is depressed. Keys 1910, 3042 control a similar clearing mechanism for the counter. Clearing the keyboard.-Depression of a key 300, Fig. 54, rocks a bail 319 which rocks release levers 320 to shift keyboard detent bars 117 so as to release any depressed keys. Ears 323 on the bars 117 latch the levers 320 in operated positions. Consequently, if the key 300 is held depressed while amount keys are operated, its further operation will not release those keys. A second key 350 directly actuates the detent bars 117 and so invariably releases all depressed keys. A lock key 3045, which is latched on depression until the key 300 is operated, rocks a pawl 3053 so that when a lever 3051 is rocked automatically as described below, at the end of multiplication or under the control of the Dividend key, the pawl 3053 will not, as normally, rock the lever 312 and actuate the keyrelease bail 319. Control clutches.-In addition to the clutches for driving the product register and counter clearing mechanisms referred to above and a shift clutch for driving the carriage as described below, the machine comprises a setting clutch, a main clutch and a master clutch. The latter operates during multiplication as described below. The setting clutch normally operates through a first half revolution (setting cycle) which is followed by operation of the main clutch, after which the setting clutch is reengaged for a second half revolution (restore cycle). A control bail 3146, Fig. 21, is rocked to engage the setting clutch by releasing a lever 1950 which raises a pawl 1952 into the path of a motor-driven ratchet wheel 1957 which shifts the pawl 1952 to the left to raise a dog, Fig. 22 (not shown), for the setting clutch. The lever 1950 is restored, when the carriage is rocked in known manner, to prevent a repeat cycle. A cam on the shaft 431, Fig. 51, driven by the setting clutch rocks a dog 395 for the main clutch 415 near the end of its first half revolution, and a further cam 3475 on the shaft 431 frees a lever 3477 which, however, is blocked by the clutch dog 395 until the end of the main clutch cycle. Then the lever 3477 rocks upwardly and raises the dog 394 for the setting clutch once more to initiate the restore half revolution of the latter. When engagement of the main clutch is not required, a bail 3147, Fig. 21, is rocked to cause a continuous complete revolution or " blank " cycle of the setting clutch. The bail 3147 rocks the control bail 3146 to engage the setting clutch, but also rocks a lever 3485 which releases a follower to the action of a cam on the setting clutch shaft 431 The follower then breaks the connection for operating the main clutch dog 395 which thus remains in the position shown so that the lever 3477 is released at the end of the first half revolution of the setting clutch to initiate an immediately following half revolution. Decimal point indicators.-Decimal point keys 3070, Figs. 1 and 2, are arranged at the bottom of the keyboard in line with the spaces between the columns of amount keys. Depression of a key 3070 rocks a lever 3174 to shift an indicator bar 3180 longitudinally so. as (a) to project its upper end 4000 to serve as a decimal point indicator for the product register, (b) to reveal a portion 3183 through an associated window 3186 between adjacent multiplier indicator drums 3000, and (c) to move portions marked in a distinguishing colour beneath a corresponding row of slots 3181 arranged between the adjacent columns of keys. The end 4000 and portion 3183 are also marked in a distinguishing colour. Depression of one of keys 3070 releases the previously depressed key and also initiates a shift of the carriage as described below. Multiplication operation.-Initially, the decimal point is set where required in the keyboard end the carriage is moved automatically to a corresponding " home " position. The multiplier is then set in correct relation to the decimal point and, on depression of an " X " key 3006, the value is transferred to the multiplier factor store and indicators 3000, the keyboard is cleared, and the carriage is automatically shifted to a position depending on that of the highest significant digit of the multiplier. The multiplicand is then set in correct relation to the decimal point and an " Equals " key 3200 (or a " Negative Equals" " key 3201) is depressed, whereupon the product register (normally) and the counter are cleared and the multiplication operation proceeds, starting with the highest multiplier digit and finishing with the lowest. The carriage is then automatically returned to the " home " position determined by the depressed Decimal point key, in which position, the result in the product register is correctly pointed by the decimal point indicator 4000. Carriage driving mechanism.-A rack on the carriage is engaged by a pinion driven through reversible gearing by a shift clutch 10, Fig. 10. When a control bail 3076 is lowered, the end 1390 of a lever 1378 enters the path of an ear 1386 which is reciprocated by the setting clutch. An interponent 1383 is coupled to move with the lever 1378 and under the control of a lever 3152 engages either an ear 1384 of a link 1374 or an ear 1217 of a lever 1219 coupled by an arm 1375 with the link 1374. Thus, when the lever 1378 is operated by the ear 1386, the link 1374 is moved in one direction or the other and cams 62, 63 of a lever 60 set the reversible gearing of the carriage drive in one sense or the other and the lever 60 rocks a trip member 50 always in the same sense to initiate a cycle of the shift clutch 10. Carriage shift under control of the Decimal point keys.-The keys 3070 have sub-stems 3102, Fig. 12, co-operating with a detent slide 3106. On depression of a key, a lug 3112 on its stem acts on adjacent ones of a series of bell-cranks 3107 interconnected by links 3110 so that all the bell-cranks to the left of the depressed key are rocked clockwise and those to the right, counterclockwise. Balls 3115 carried by the bell-cranks co-operate with a member 3116, Fig. 13, carried by a nut on a worm shaft 3097 driven synchronously with the carriage. The member 3116 is normally aligned with the depressed decimal point key, the balls 3115 being positioned relatively to the member as shown in Fig. 15. When another key is depressed, the movement of one of the balls 3115 due to the new arrangement of the bell-cranks 3107, shifts the member 3116 upwardly or downwardly according to whether the newly depressed key is to the right or left of the previously depressed one. A ball 3123 fast with the member 3116 moves in a channel-shaped member 3124 which is thus rocked correspondingly to move a roller 3128, Fig. 17, carried thereby to position 3128a or 3128b. A lever 3130 is thus able to rock through one or two steps of movement and with it a lever 3139 which allows a lever 3145 to rock the bails 3146, 3147, which as described above, initiate a complete " blank " cycle of the setting clutch. The lever 3130 has a slot receiving a stud 3148 of a link 3149 and, on rocking of the lever 3130, the link 3149 (see also Fig. 10) lowers the bail 3076 to cause operation of the carriage shift clutch 10. The shift mechanism is normally conditioned for a left shift, but when the lever 3130 is permitted two steps of movement, a stud 3151 carried by the bail 3076 rocks the direction-control lever 3152 to cause a right shift. When the member 3116, Figs. 13 and 15, reaches its new " home '' position, it contacts the first ball 3115 of the oppositely-set group and is cammed thereby back to the position of Fig. 15. The lever 3130, stud 3148 and bail 3076 are thus restored. As the stud 3148 is restored, it rocks a latch, Fig. 43 (not shown), for the arm 1375 to release the carriage drive initiating mechanism, and the carriage comes to rest in its new " home " position. Entering the multiplier.-The selection bars 120, Fig. 2, differentially positioned by the depressed keys rock levers 3001 correspondingly, and on depression of the " X " key 3006, a bail 3007 is lowered to free stepped plates 3005 for differential rocking movement into contact with ears 3004 of the levers 3001. Further stepped plates 3204 follow the plates 3005 under the action of springs and are coupled by links 3208 to segments 32