Patent GB-821054-A (GB)
Title: Accumulator for accumulating fractions
IPC: G06F7/46
Filed: 1956-03-12
Abstract: 821,054. Digital-electric-calculating apparatus. INTERNATIONAL BUSINESS MACHINES CORPORATION. March 12, 1956 [March 15, 1955], No. 7609/56. Class 106 (1). In a cyclically operable accumulator for accumulating fractions, the numerator of the fraction is treated as a normal digit value for entry into the accumulator during normal entry time and the denominator is used to derive a correction value, the tens complement of the denominator, which is entered into the accumulator-following a carry operation, the correction entry being terminated in the normal entry time of the next cycle, but before entry of the next numerator value. These operations are repeated for each numerator value entered into the accumulator. The accumulator used is of the kind in which zero setting is indicated by a nine in each decimal order position and, in addition to the normal carry between adjacent order positions, a round carry means is provided between the highest and lowest order positions. When the first numerator value is entered the carry means are set up and become effective immediately after completion of the numerator entry to effect the carry operation and immediately thereafter the correction value is entered. If the fraction is positive the entries are additive; if they are negative the numeral value is entered in complement form. The accumulator.-The accumulator, Fig. 3, comprises an adding magnet AM and a stop magnet SM adapted to control a pivoted armature 45 connected to the control lever 21 of a clutch. The armature 45 is biased against the core of magnet SM, but on energization of magnet AM the armature is displaced to rock the control lever 21 downwards. A latch 35 holds the lever in either position. In the downward position it releases a disc 20 for counter-clockwise movement so that a spring 31 is enabled to rock clutch pawl 30 into engagement with a constantly rotating ratchet-wheel 16 to start an accumulator element 24 rotating. The rotation is ended by energization of the stop magnet SM during a subtractive entry or by the usual knock-off lever 50 associated with the accumulator. Spaced pins (e.g. 52) on this lever engage lever 21 to terminate entries at 155 degrees and carry operations at 336 degrees. Carry means are provided to give a signal when the accumulator reaches 9 and also when it passes from 9 to 0. These consist of a follower 24a which co-operates with accumulator element 24 and is shaped so that at " 9 " position a contact blade 239 makes contact with the " nines " contact 241 and when passing from 9 to 0 the blade 239 transfers to make contact with " tens contact 240. These contacts control carry operations from one order position to the next higher position. Card sensing.-A well-known type of card feed is used which feeds the cards in succession past brushes adapted to sense the perforations in the usual way. The cards are sensed twice, the first sensing serving to set the machine for additive or subtractive entries. First and second sensing stations for card columns 1, 2 and 80 are shown in Fig. 1a. The sensing brushes are connected to control the operation of the accumulator by plug connectors. Each card position is associated with a commutator 164, the segments of which are energized in turn by a brush 165. The circuit is completed through the particular brush which passes through the card perforation. Read in.-Two relays R149, R371, Fig. 1b, are energized to prepare the accumulator for additive operations. When relay R371 is picked contacts R371c (lower right hand corner, Fig. 1b) close to allow the signal read from the card to pass from plug connection 975a, through plug 976, contacts R445e normally closed (n/c), R223c (n/c), R149e normally open (n/o), R371c to the adding magnet AM. The value read from the card at the second sensing station is thereby entered into the accumulator. All accumulator orders normally stand at " 9 " so that if a 5 is to be added the accumulator advances through positions 0, 1, 2, 3 and stops in position 4. The tens contact 240 is closed when transferring from 9 to 0 and initiates a carry which changes each higher order to 0 and the round carry changes the value 4 to the correct 5. Read out.-Each order position has an associated read-out brush 1044 which makes contact with a common contact 1045 and with the digit points 1049 representing the value in the accumulator order. The digit points 1049 receive digit impulses transmitted by No. 1 Total Print emitter and, according to the digit position of each order selected impulses are transmitted to the printer control magnets. If the value in the accumulator is negative the accumulator value will be read out as a nines complement. Under this condition relay R75 would transfer all the associated contacts and cause the impulses from the emitter to be applied to the digit points in the opposite order so that a 9 value will be read out as 0 and so on. Relay R75 is picked automatically when 9 is sensed in the highest order position, this indicating a negative total. Fractional operations.-The operation is described in respect of sixths although provision is made for accumulating fractions of any selected denomination by plugging relays RE, RF, RG, RH as shown in Fig. 1c. These relays carry the values 1, 2, 4, 8 so that for sixths relays RF and RG are connected as shown. Further relays RA, RB, RC, RD are arranged to be picked through contacts REa, RFa, RGa, RHa. This circuit is completed through contacts R75a n/c, Fig. 1b. Contacts of relays RE, RF, RG and RH are arranged in two pyramids connected to the No. 1 Total Print Emitter (Fig. 1b) and a No. 2 emitter (Fig. 1c). The outputs from the pyramids are connected to control add magnet AM and subtract magnet SM of the units order of the accumulator. The contacts of relays RA, RB, RC, RD are arranged in ten networks between the units order read-out segment 1045 and ten lines 0-9, Fig. 1d. The line 1045a from the read-out segment is connected to contacts R445c, Fig. 1c, which, when transferred, connects the read-out line to the accumulator exit plug. This plug is normally connected to a printer for printing the value read-out. Entry of correction value.-The setting up of the relays RE-RH presets the accumulator with a correction value corresponding to the fraction being processed. The pyramid of relay contacts connected to the No. 1 emitter select one of the emitter points 0-9. Where the fractions are sixths, relays RF and RG are energized so the circuit is completed to the " 7 " point. If the accumulator is standing at zero with 9 in each order and 5 is entered, the units order passes through 0, closing tens carry contact 2401, Fig. 1c, to position 4. This contact is also used to initiate entry of the correction value, i.e. the difference between the numerator and ten. Normal carry is effected towards the close of the machine cycle, the carry advancing all orders by one position as described above. Simultaneously, a presetting latching relay RJ (Fig. 1c) is picked through contact 2401. A cycle point later when cam contacts CR210 make the add magnet AM is energized and the correction value begins to be entered into the units order of the accumulator and continues till stop magnet SM is energized. This is effected through the contacts RJa n/o, RHc n/c, RGc n/o, RFd n/o, REd n/c to 7 wire (Fig. 1b) and 7 spot on No. 1 emitter. Cam contacts CR210 closed one index point before the end of the cycle (Fig. 2, not shown) and 7 spot of the No. 1 emitter is energized in the third cycle point of the next cycle. This allows the units accumulator to advance 4 positions, the corrections entry required for sixths. In the next cycle point the relay RJ is released by energization of the latch trip coil LT, Fig. 1c. Coil LT is energized through a pyramid of contacts of relays RE-RH connected to the 6 spot on the No. 1 emitter. Subtraction.-For subtraction the numerator is entered subtractively by energizing the magnet AM (Fig. 1c) with an impulse the time value of which is one less than the denominator of the fraction. For sixths it is energized at " 5 " time. The subtract magnet is energized when the numerator value is sensed. Towards the end of the cycle the correction operation is effected to enter a value of 4 in the units order. If 3/6 is to be subtracted the numerator 3 is perforated in the card as a digit value 3 and the relays RF, RG are plugged to represent 6. The contact pyramid to magnet AM connects it to the 5 segment of No. 2 emitter so that AM is energized at 5 time in the cycle and the units order wheel advances until a pulse initiated by the 3 perforation in the card is directed through the entry plug to energize the subtract magnet SM after two cycle points. Since the wheel originally stood at 9 the advance is to position 1 the tens carry then advancing all orders one position so that 2 is registered in the units order. The correction value of 4 is now entered so that the value is increased to 6. This, being negative, is read out as a nines complement, i.e. 3 sixths. Read-out correction.-The relays RA-RD serve to correct the over valued contents of the accumulator when reading out. The line 1045a is connected to the exit plug, Fig. 1c, and thence to a printer. The read-out points 0-9 are connected by labyrinths of relay contacts to the ten lines 0-9 of the print emitter so that according to the denominator plugging of relays RE-RH a correction is made in the connection between read-out points and the No. 1 emitter lines. Thus if there is a value 8 in the accumulator and the relays RF, RG are plugged to indicate sixths, relays RB and RC will be picked so the circuit will be completed from 8 point through contacts RDh n/c, RCn n/o, RBv n/o and RAm<SP>1</SP> n/c to 4 line so that the value 4 will be printed. This is correct since the number in the accumulator is over-valued by the tens complement of the denominator, i.e. 4. Denominators more than ten.-Where