Patent GB-392965-A (GB)
Title: Improvements in or relating to subtracting mechanisms
IPC: B01J13/00
Filed: 1931-11-27
Abstract: 392,965. Subtracting-mechanism ; statistical machines. BRITISH TABULATING MACHINE CO., Ltd., Victoria House, Vernon Place, Southampton Row, London, and KEEN, H. H., 27, Norton Road, Letchworth, Hertfordshire. Nov. 27, 1931, No. 32938. [Class 106 (i).] Adding and subtractig; total-taking.-Subtracting - mechanism comprises, for each denomination, two set-up devices (counterwheels) to represent minuend and subtrahend two differentially-movable subtracting members (48M, 68 and 48S, B1), which are individually set by the set-up devices so that the relative displacement of these members represents the difference (or complement) between minuend and subtrahend, and a device controlled by the two subtracting members for indicating, registering or recording the difference for that denomination. The invention is applied to a machine generally similar to that set out in Specification 247,200, [Class 106 (i), Calculating &c.] : preferably each minuend subtraction member carries conducting segments which co-act with brushes on the corresponding subtrahend member, the two members being rotated in the same direction. The counter includes counter-magnets 17, Fig. 7, which when energized, clutch the counterwheels to a countershaft to add the amounts in the usual manner The cards pass upper and lower brushes UB, LB, Fig. 6, and are preferably grouped for major and minor control. The magnets 17 are energized by the lower brush readings. The vertically rising, differentially-arrested type bars are controlled by the printer magnets 18, Fig. 7. The reading-out mechanism for the counters is actuated synchronously with the type bars and is of the well-known stepped-cam type in which the cams co-operate with lever swhich are rocked from a shaft 19, Fig. 3, controlled by cam 20 on reading-out shaft 14. Each lever when arrested by its cam according to the digit, will close contacts 22-DB (or 22-CR), Fig. 7, at a differential time. The shaft 19 also drives the subtracting mechanism, rack 22 rotating a wheel 24 which is rotatable on shaft 25 and carries a disc 27, the notch 27a of which is adapted to be engaged by a pawl 29 pivoted to a disc 28 rigid with shaft 25. Subtraction magnet 33 and latch 32 control this clutch, so that oscillation of rack 22 only drives shaft 25 if magnet 33 has been energized. Thus shaft 25 is rotated counterclockwise until stop member 34 on its disc 28 latches beneath a nose 35 on a latch 36 pivoted at 45 on armature 43. When rack 22 and wheel 24 are restored, the shaft 25 is thus held. A disc 37 rigid with wheel 24 carries a pawl 38 engaging a notch 39 in a disc 40 secured to shaft 25. When rack 22 reaches its extreme left position, Fig. 3, the tail 42 of pawl 38 engages the top of the armature 43 and the pawl is rocked out of notch 39. This allows the wheel 24 to be restored whilst the shaft 25 and disc 28 are retained by latch 36. Magnet 44 is normally de-energized. At a group change, there are two total-printing cycles made up of four halfcycles. During the first half-cycle the reading- out levers are rocked, the type bars are positioned and printing effected, and shaft 25 is rocked and latched as above. Shaft 25 remains thus during the second (used for counter-resetting) and third half-cycles and towards the end of the third, magnet 44 is energized to release nose 34 and remove the armature end away from the tail of pawl 38. Thus during the fourth half-cycle, pawl 28 remains in notch 39 and restores the disc 28 and shaft 25. There are ten pairs of subtraction members mounted to rotate on shaft 25; each pair forms a denomination and consists of a minuend and a subtrahend member. Each member includes a sector 48, Fig. 5, whose surface 49 is held by spring 51 against a pin 50 on an arm 52 rigid with shaft 25. Each arm coacts with two adjacent sectors (except the two extreme arms). Thus clockwise rotation of shaft 25, Figs. 3 and 5, restores sectors 48, but as shaft 25 rocks counterclockwise, each sector 48 follows its pin 50 until arrested by its teeth and members 53, 56 when magnet 58 is energized. The teeth move past pawls 53 synchronously with the passage of the type past the printing line. Magnets 58 (minuend 58M and subtrahend 58s), Fig. 7) are energized by the reading-out contacts 22 and are thus energized simultaneously with the printer magnets 18. The ten magnets 58M are controlled by contacts 22-DB of the debit (minuend) counter DB, and the ten magnets 58s by the contacts 22-CR of the credit counter (subtrahend) CR. During the total-printing cycles, the sectors 48M, 48s are positioned during the first half-cycle and are restored in the fourth half-cycle. The left and right hand halves of Fig. 8 show positions of the parts for two computations. Each subtrahend sector 48s is rigid with a commutator 60, the rings 61, 62, 63 of which coact with brushes 64, 65, 66 and are connected to brushes BT, B1 .. B4 which are carried by the sector 48s. The brushes B1 .. B4 contact with the segments 68 of a commutator 67, which is rigid with the coacting minuend sector 48M. The segments 68 are connected to rings 69 which co-operate with fixed brushes 70. Brushes B1 .. B4 and segments 68 rotate in the same direction so that if a minuend sector is arrested for digit 9 and the corresponding subtrahend sector is arrested for digit 5, then brush B2 will rest on segment 68, No. " 4," representing the difference. Each commutator 67 also carries two rings 72, 73 which coact with brushes 74, 75 and are connected to a long transfer segment LT and a short transfer segment ST. Subtraction circuits. The reading-out contacts 22-DB and 22-CR of the counter wheels are plugged by wires 76 in the correct denominational order to the magnets 58M, 58s; with the latter are associated the contacts 77a, 77b of a single relay 77, Fig. 6, which is energized at a balancing operation when the credit and debit totals are printed and then transmitted to the subtracting mechanism. During the first of the four total-printing half-cycles, contacts 77a, 77b are in the position shown in Fig. 7, but during the second half-cycle these contacts are reversed. As set out above, the credit and debit totals will be printed from counters DB, CR, the counters reset, and the sectors 48M, 48s positioned according to the totals, by the end of the second total-printing half-cycle. Two impulse emitters 86, 87 have their brushes 88, 83 driven by the reset motor synchronously with the rise of the type-bars. Brush 88 connects a line 90 in turn to eleven (pence) segments connected by lines 89, 92 to the lowest, or pence, commutator 67. Brush 93 similarly connects line 95 to nine segments and lines 94, 93 to brushes 70 for the tens and units of pounds and units of shillings. The " 1 " line 94 is also connected to a line 109, which leads to the " 1 " and " 9 " digital segments on the tens of shillings commutator 67. Transfer mechanism.-Printing a positive balance. The right-hand half of Fig. 8 shows the positions when 382 is subtracted from 906. The units minuend and subtrahend sectors rotate during the first total cycle four and eight steps (since the " 9 " hole positions pass the reading brushes first) so that brush B2 rests on segment " 4 " (the difference). During the second total cycle, emitter 87 establishes a circuit, at the " four " time in the cycle, over a line 93, the commutator segment 68, Fig. 8, segment 63, brush 66, contacts 95a, Fig. 7, line 110, contacts 91c, contacts 77b, line 82, and the appropriate printer magnet 18 which positions the type-bar to print "4." In the tens, Fig. 8 right half, the subtrahend (8) exceeds the minuend (0) so that borrowing is necessary from the hundreds minuend. The minuend sector moves ten teeth and the subtrahend moves two teeth. This positions brush B1 on segment 68 No. " 2 " so that two is printed, and also sets brush BT on the short transfer segment ST, so that a circuit 75, 73, ST, BT, 61, 64 connects brushes 75, 64. These tens brushes thus connect line 100, Fig. 6, to the hundreds transfer coil 97 which reverses the contacts 97a, 97b so that they are positioned as shown in the upper right-hand corner of Fig. 8. In this hundreds denomination the subtraction " 3 " from " 9 " has been set and brush B2 rests on the six segment 68. The reversal of contacts 97a, 97b, however, has opened the circuit of brush B2 at 97a; but at the " five " time a circuit 97b, 65, 62, B4, " 5 " segment 68 is made so that " 5 " is printed instead of "6." For along borrowing the brush BT of the next higher denomination would be set on the long transfer segment LT to carry the circuit on to a still higher denomination. Fig. 8, right half, illustrates a decimal subtraction ; Fig. 7 shows the emitters 86, 87, &c. arranged for pounds, shillings, and pence. In a modified arrangement, the brushes B2, B3 are omitted and an escapement mechanism is actuated at transfer to allow the minuend sector to move forward one step so that brush B1 engages the segment 68 for the next lower digit. Printing a negative balance. The left half of Fig. 8 shows the positions for printing a negative balance. In this case the sectors 48M, 48s are so positioned that they give the "tens complement of the actual difference. This is inconvenient since to print the real difference, translating mechanism is used to print the complement of the complement. The above " tens complement " is, therefore, converted into a " nines complement " by introducing the " fugitive one." For this, one is borrowed from the units denomination, the units sectors magnet 05, Fig. 6, controlling contacts 95a, 95b, Fig. 7, being connected to the brush BT for the highest denomination. For printing the complement of the complement to get the real (negative) difference, the magnet 91, Fig. 6, is energized. This reverses the contacts 91a, 91b at the emitter 87, Fig. 7, so that the lines 94 are connected to the lines 93 in the reverse order. Item-entering. As the cards pass th