Patent GB-673937-A (GB)
Title: Improvements in or relating to apparatus for finding recorded data
IPC: G06F7/46
Filed: 1948-08-06
Abstract: 673,937. Digited electric calculating-apparatus. BRITISH TABULATING MACHINE CO., Ltd. Aug. 6, 1948 [Aug. 14, 1947], No. 20802/48. Class 106 (i). In apparatus for selecting or " looking-up " values of a table recorded on one or more members, e.g. tapes, one of which has argument values consecutively represented thereon while the same and/or other member(s) carries corresponding functional values, comprising sensing- stations, each including means for feeding a record member and means adapted for sensing argument and/or functional values, means (controlled by a registered argument value, e.g. from associated computing apparatus), and argument-sensing means feed the record member(s) to a position whereat sensing means can read out functional values corresponding to a recorded argument value having a predetermined mathematical relation to the registered value. The look-up apparatus described comprises 36 stations each comprising a rotatable drum carrying a removable perforated record tape, the tapes bearing representations of ordered values and functions as in mathematical tables. The apparatus is designed to be controlled by computing apparatus such as that described in Specification 600,896. Computed values entered in binary code form as voltage impulses are registered and compared with record tape argument values, similarly coded, sensed by electric contact brushes. A tape value corresponding to, though not necessarily equal to, the computed value is selected and may be read out in the form of other voltage impulses, together with the associated functional value or values, by a second set of sensing brushes. The controlling circuits of the apparatus, consisting primarily of relays and tetrode valves, are designed to deal with up to six different mathematical tables of values at a time, each table comprising one or more tapes for functions. The selecting operation involves selecting the correct station within a table and then selecting the required value on the tape at that station. Record tapes and stations. Each record tape has transverse lines of 78 perforation positions, Fig. 2, which are divided into groups of four to represent numerals according to a binary code, Fig. 3. As shown, the first 22 positions are used to represent a 5-digit argument value and its sign, and the remaining positions for one or more functions of that value. Other tapes may be used to record functions only. Each tape forms a continuous loop and has feed-holes 10 which are engaged by pins 11p on a station drum 11, Fig. 6. The drum is clutched to a continuously rotating shaft 20 upon energization of station clutch magnet SCM, Fig. 4. A ratchet 23 is fixed to the shaft and coacts with a dog 30 pivoted to a toothed disc 28 carried by a sleeve freely rotatable on the shaft and geared to the drum. A toothed disc 29, freely mounted on the sleeve between disc 28 and ratchet 23, has an elongated slot for the pivot of the dog which has a tail 30c pivotally engaging part of the disc 29. Springs 31, 32, connecting studs on the disc 29 to the dog 30 and a stud on disc 28 respectively; urge disc 29 clockwise relative to disc 28. The armature 33 of the magnet SCM normally engages the teeth on the disc to prevent this relative movement, which, however, occurs when the magnet is energized, thus rocking the dog into engagement with the ratchet 23. The discs, sleeve and drum then rotate until, upon de-energization of the magnet, the armature 33 causes re-alignment of the teeth of discs 28, 29 to disengage the clutch. The drum comprises a contact cylinder continuously engaged by a brush CB, Fig. 6, and the perforations are sensed by two sets of brushes SB, RB spaced two lines apart. The 22 brushes SB are used for sensing values while the tape is continuously moving to select the required data. The 78 brushes RB are used for reading out values and functions while the tape is at rest. The tape is held taut by pressure fingers 48 fixed to shafts 63. When it is desired to remove or insert a record tape, the brushes SB, RB are moved away from the drum by manually rotating an eccentric shaft. One end portion 50a, Fig. 4, of the shaft carries a one-way ratchet 57 and a disc 58 having two diametrically opposed notches which are engaged by a detent 60 to hold the shaft in both its normal and brush-retracting positions. Cams 66 on the portion 50a engage arms 64 on the shafts 63 so that the fingers 48 are also moved away from the drum. Storing station values. Each station is represented for selection purposes by the last value on the record tape at that station. The value is stored by selectively energizing a set of 22 relays S-TA, Fig. 13h. When a tape is first installed at a station, the station magnet SCM, Figs. 4 and 131, is energized by closing a switch SMK to rotate the drum 11 until the perforations representing the last or station value lie under brushes RB, Figs. 6 and 13j. Switches (not shown) are closed according to the number of digits in the value, to energize relays CTSM1-CTSM5, Fig. 13h, and double-pole switches MTS1-MTS3 are set according to whether the sign of the station value is to be stored as recorded or in reverse or whether a fixed sign is to be stored. A station storage switch MSK, Fig. 6, is then closed which energizes a corresponding relay MSS, Fig. 13h, and also momentarily energizes relays (not shown) whose armatures normally latch the attracted armature of the storage relays S-TA, to clear those relays of the previously-stored value. The relay MSS closes contacts (not shown) to energize a relay CSS, Fig. 13j, which directs the RB brush circuits to the control grids of tetrodes RV3-RV22 for the numeral value and RV1X, RV2X via switches MTS1- MTS3 for the sign. Whenever there is a perforation in the RB position the corresponding tetrode will conduct to energize the relay S-TA. Comparing tape values with entered values. A comparison device is provided for comparing each station value with an entered value which may be sent from associated computing apparatus. Further comparison devices are provided for comparing the entered or computed value with that sensed by the RB and SB brushes at a selected station and with the value on the tape between the two sets of brushes. Each device comprises relays TA, Fig. 9, energized according to the tape value (or " argument ") and relays CA energized according to the computed value. Potential is applied to line 80 and appears on one of the five lines shown at the right of Fig. 9 as the result of a successive comparison of first the signs and then the binary numeral positions (four for each digit or " group ") of the two values. If the signs differ, potential appears on line TSH or CSH. If the two values have the same sign but differ in magnitude, potential appears on line TAH or CAH according to which value is the greater. If the values are equal potential appears on line CET. Each comparison device also comprises a terminal portion which for a station device is as shown in Fig. 10. Each of these terminal portions comprises contacts of relays TA+, TA-, to take into account the sign where this is the same for the two values, and of relays SA, SD corresponding to an ascending and descending table of values, respectively, and directs potential to one of the output lines such as A and B. Entry of values and commencement of operations. The values for which a " look-up " operation is required are entered in the binary code form of Fig. 3 by selectively applying potential to 22 conductors (not shown) either from computing apparatus or by selectively operating key-operated switches. When power is first applied to the main voltage lines of the circuits a relay R37, Fig. 13k, is momentarily energized through a capacitor (not shown), thereby applying potential to the control grids of tetrodes V232, V231 which then conduct and energize relays R40, R41 which are held through contacts R40b. This causes energization through manually or automatically controlled contacts of a pick-up relay R11, Fig. 13e, and thus, successively, of a series of relays including R13, Figs. 13e and 13k, which thereupon opens contacts R13a, to de-energize relays R40, R41. The relay R13 controls the energization of relays CA, Fig. 9, in accordance with the entered value. The table to be looked up is selected by energization of a relay TL, Fig. 13e either automatically by programme-controlled circuits or by key-operated switches, thus energizing corresponding relays TLD, TLF. These relays are held until relay R40 is again energized at the completion of a look-up operation, as described below, thus opening contacts R40c. Station selection. The comparison devices for stations containing the record tapes or a table, e.g. stations 1, 2 and 3 for table 1, Fig. 14, are previously connected up by plugging, indicated by broken lines in Fig. 13f, so that if, e.g. table 1 is selected, and relay 1TLF, Fig. 13e, is energized, potential is applied through contacts 1TLFg to the input line 80 of the station 1 comparison device. If this station is not selected, potential is applied to output line B and sent to the station 2 comparison device, and so on until a station is selected. Potential is then applied via an output line A to the control grid of a tetrode ST which thereupon conducts and energizes a corresponding relay SS. This relay closes contacts (not shown) to energize the relay CSS, which closes contacts in the circuits of the station clutch magnet SCM, Fig. 13L, and relay DSS, Fig. 13j, which relay closes contacts in the circuits of the brushes SB for the selected station. A relay SQ, Fig. 13k, is also energized momentarily. Selecting recorded values in a station. Suppose that station 1 is selected, Fig. 14, so that relay 1SS and thus relay 1SQ, Fig. 13k, is energized. Potential is then applied via line W101 to the control grids of tetrodes T228, T233, thus energizing a relay IS1. This initiates energization of a