US2386481A - Calculating machine for effecting division - Google Patents

Description

Oct. 9, 1945. w. LANG CALCULATING MACHINE FOR EFFECTING DIVISION Filed Dec 21, 1942 9 Sheets-Sheet 1 Wm v I; ffINVENToR Q *7 ATTORNEY wan Q 53 2T3 III ll Oct. 9, 1945. w. LANG 2,386,481

CALCULATING MACHINE FOR EFFECTING DIVISION Filed Dec. 21, 1942 9 Sheets-Sheet 2 A T TORNE Y FIGJ Oct. 9; 1945. w. LANG CALCULATING MACHINE FOR EFFECTING DIVISION 9 Sheets-Sheet 3 \wwwk d 3 Filed Dec. 21, 1942 QuEwt 53f lllllll lllll IIIIII N g K a aw INVENTOR M437 ATTORNEY Oct. 9, 1945. w. LANG 2,386,481

CALCULATING MACHINE FOR EFFECTING DIVISION Filed Dec. 21, 1942 9 Sheets-Sheet 4 J17 v '7 INVNTO R ATTORNEY w. LANG 2,386,481

CALCULATING MACHINE FOR EFFECTING DIVISION Filed Dec. 21, 1942 9 Sheets-Sheet 5 Oct. 9, 1945.

ATfoRNEY 1945- w. LANG 2,386,481

CALCULATING MACHINE FOR EFFECTING DIVISION Filed Dec. 21, 1942 9 Sheets-Sheet 6 FIGS.

n (my INVENTOR AIT'TORNEY Oct. 9, 1945.

FIGAO.

9 Sheets-Sheet 7' FIGJ2.

W flgirozz A T TORNE Y w. CALCULATING MACHINE FOR EFFECTING DIV Oct. 9, 1945.,

I ION Filed Dec 221, 1942 9 Shasta-Sheet l h "3 R b WILL/A ATTORNEY QWR m I MQQ NW $65k m3 Nb mm Oct. 9, 1945. w. LANG CALCULATING MACHINE FOR EFFECTING DIVISION Filed Dec. 21, 1942 9 Sheets-Sheet 9 5% NQMQ .3 N Qwkw lNVENTOR W/LL/AM LANG ATTORNEY GN ME Patented Oct. 9, 1945 CALCULATING MACHINE FOR EFFECTING DIVISION William Lang, New York, N. Y., assignor to International Business Machines Corporation, New York, N. Y., a corporation of New York Application December 21, 1942, Serial No. 469,655

12 Claims. (Cl. 235 61.8)

This invention relates to improvements in division machines for computing quotients and remainders from dividend and divisor factor data, and particularly in machines controlled by data expressed in accordance with the binary system of notation.

With previous division machines, especially those operable in accordance with the decimal system of notation, the dividend and divisor are first entered into the machine, thereafter subtraction is started, the divisor being subtracted from the dividend beginning in the highest possible orders of the dividend. Subtraction continues inthat order until the result of the dividend accumulator passes through zero or goes back of zero. Then, the customary procedure is to add back the divisor once into the dividend accumulator, thereafter the divisor is shifted over one place relatively to the right and the above subtraction operation is repeated. A quotient accumulator is customarily provided to keep account of the number of ubtracting operations in each denominational order.

According to the present invention, the several factors are expressed in the binary system of numeration, and the calculations are carried out in such system. Accordingly, a binary accumulator is provided to initially receive the dividend, the several orders of such accumulator being allocated to the terms of the binary progression as is well known. The divisor factor is set up on a suitable device which for illustrative purposes is another binary accumulator but, since no calculating is to be performed in this device, it need not have the carry devices of an accumulator and may be simply a set of ordered relays.

A comparing mechanism is provided which inspects or canvasses the initial dividend and divisor settings and effects a column shift to align the highest value positions of the two factors. A direct subtraction takes place which may or may not result in an overdraft. If no overdraft results, a further comparison, column shift and subtraction again take place between the remalnder and the divisor.

A binary quotient accumulator is provided into which for each subtracting operation a value is entered in accordance with the extent of column shift effected. Since in the binary system a shift of an amount one order in an ascending direction doubles the amount and a shift of two orders quadruples the amount, etc., the multiples of the divisor that are in effect subtracted are multiples of the binary progression. Thus, a twoplace column shift and subtraction are accompanied by an entry of a, four in the quotient accumulator.

Upon the occurrence of an overdraft, instead of reintroducing the divisor into the dividend accumulator, then effecting a column shift and then subtracting the divisor from the dividend accumulator, a novel procedure is followed. Column shift is"eifected one order to the right (i. e. in the descending direction) and addition of the divisor instead of subtraction is carried out. The result is the same as though the first divisor were added back and then shifting over and subtracting the lower divisor, thus obtaining the same result in a single step. For example, if the divisor shifted to a position representing four times the divisor resulted in an overdraft, instead of adding back four times the divisor, column shifting and then subtracting the next lower multiple of 2 times the divisor, 2 times the divisor is added after the column shift. Thus, minus 4 times plus 2 times gives the same result as minus 4 times, plus 4 times and minus 2 times.

Similarly, in the quotient accumulator, when an overdraft occurs, there is a column shift and the subtraction of the next lower binary value which results in the true quotient figure in such accumulator.

The principal object ,of the invention is to provide a division machine based on the binary system of notation in which division may be carried out with simplified structure and a minimized number of steps of operation.

A specific object of the invention is to provide an improved comparing mechanism for controlling column shift devices between dividend and divisor entry receiving devices for the direct subtraction of the binary multiples of the divisor from the dividend.

A further object is to provide improved control of column shift devices by overdraft mechanism to directly modify the column shift adjustment as effected by the comparing mechanism to bring about an entry of the next lower binary multiple of the divisor.

A still further object resides in the provision of devices for automatically effecting a recording of the quotient when the dividend has been reduced to an amount less in value than the divisor.

Another object resides in the provision of a binary accumulator adjustable to selectively add or subtract together with controlling devices for automatically effecting such adjustment in accordance with overdraft conditions occurring during dividing operations.

Other objects of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of example, the principle of the invention andthe best mode, which has been contemplated, of applying that principle,

In the drawings:

Figs. 1. 1a and lb taken together and arranged vertically in the order named show the circuit diagram! the machine.

Fig. 2 is a plan view of part of an accumulator.

Fig. 3 is a section through an order 01' the accumulator, the section being taken on lines 3-8 of Fig. 2.

Fig. 4 is a transverse section taken on lines 4-4 of Fig. 3.

Fig. 5 is a section taken on lines 5-5 of Fig. 4.

Fig. 6 is a detail of parts in the plane or lines 5-8 of Fig. 4.

Fig. 7 is an expanded diagram of several orders of the accumulator to show the interorder connections.

Fig. 8 is an expanded view of the several parts of an accumulator order.

Fig. 9 is a detail of the differential, the section being taken on lines 8-5 of Fig. 8.

Figs. 10, 11 and 12 are examples of representative problems illustrating the calculating steps involved in their solution.

Figs. 13 to 17 are diagram showing the sequence of operation or the electrical devices during several steps of operation.

The card The card which controls the operation of the machine is shown in Fig, 1 where it is designated l5. Its surface is divided into columns of designation receiving position arranged in dividend, quotient and divisor groups with the positions in each group having values corresponding to the terms of the binary progression. Thus, in the dividend group the amount 298 is recorded by perforations along a horizontal line in the 256,

- 32, 8 and 2 position. A divisor amount of 27 is similarly recorded by perforations in the related group in the 16, 8, 2 and 1 positions.

Card sensing For purposes of simplicity in illustrating the invention, the card. I0 is shown as being manually insertible into sensing, position against a stop II which locates the card with the horizontal line of perforations representing the dividend and divisor in register with a line of sensing elements comprising groups of brushes l2 and I3 which make electrical contact through the perforations with a common contact bar i 4.

The dividend accumulator one for each accumulator element designated 55-i, 55-2, 54-5, 54-8, etc. The mechanisms controlled by these magnets are similar so that explanation of one will suillce for all, and in describing the same like reference characters are applied to similar parts in the several like sections of the accumulator. Magnet 54-! (Fig. 3) when energized attracts its armature 55 against the action of tension spring 58, whereby a leaf spring 51 whose free end is biased downwardly will move toward the left into engagement with the next tooth of ratchet 58.

Upon deenergization of magnet 5l-l, the spring 55 will return the armature, and member 51 will advance ratchet 58 one tooth in a clockwise direction. Referring to Fig. 5, it will be seen that, when magnet 54-2 is energized and then deenergized, its spring 58 will advance the related ratchet 58 one step in a counterclockwise direction. Carried by each ratchet 55 is a pair of meshing differential pinions 55 and 55 (see also Figs. 8 and 9). In the section associated with magnet 55-l, the pinion 59 meshes with an internal ring gear 5| (see Fig. 4) which is mounted on cross-bar 52 and held against rotation by a pin 53 extending from one of the side plates 53. The pinion 55 meshes with an internal ring gear 54 formed in a cam wheel 55.

The unit comprising the parts 58, 55, 50, 5| and 55 constitutes a differential mechanism effective to cause the cam wheel 55 to be advanced twice the angular distance that ratchet 58 is moved. The cam wheel 55 is provided with high and low portions as shown in Fig. 3, whose spacing is twice that of the teeth of the ratchet 58, so that when the ratchet 58 is advanced one tooth, the cam 55 will move a distance measured between adjacent high and low parts of the cam. Each of the cam wheels 55 is provided with a second internal ring gear 55, of which alternate teeth are missing, thus forming a mutilated gear which meshes with a pinion 51 carried by an arm 58 normally maintained in the position shown in Fig. 6, The pinion 51 is rotatable on the arm 58 and through a suitable bushing is secured to a pinion 59 which meshes with an internal ring gear III on a wheel H.

The operation is such that, whenever the cam wheel 55 advances two steps, the mutilated gear 55 engages and turns pinion 51 which in turn through pinion 59 advances the wheel 1|. Wheel 1| corresponds to the member 5| in the lower position and has a corresponding internal gear also designated 5 I.

In Fig. 7, the entire differential gear arrangement for the lowest four orders is shown in diagrammatic form which shows the relationship of the parts more clearly. From this figure it can be seen that each of the four ratchets 58 may be advanced step by step and through its differential 59, 50 advances its related cam wheel 55. When any wheel 55 advances two steps or multiples of two steps, it will operate the carry gear 51, 55 to advance the next wheel H so that its related cam wheel 55 advances one step. The last cam wheel 55 through its carry gears 51 and 58 controls the operation of a fifth cam wheel 55 which is the overdraft element.

It is to be noted in Fig. 7 that ratchets 58 in the 1 and 4 positions are stepped clockwise and in the 2 and 8 positions they are stepped counterclockwise to effect an entry. When the 1 ratchet 58 is moved clockwise, it moves its pinion in bodily in the same direction which causes the related disk 55 to rotate. At the same time, pinion OI is rotated counterclockwise through its engagement with pinion 50 which is constrained to roll on the teeth oi fixed disk 8|. This provides the diii'erential action that causes cam disk 85 to turn twice as far as the ratchet 58.

The same action is obtained in the 2 position where,-when ratchet 58 is stepped one step in a counterclockwise direction, the 2 disk II is conatrained against clockwise rotation because it mshes with pinion 68 whose companion pinion i1 is locked against clockwise turning by a tooth C (see Fig. 8) on the wheel 85, which in turn is locked through pinion 60 to locked ratchet 58 in the 1 position. It is to be noted in Fig. 6 that whether the teeth 66 are in full line or dotted line position, pinion 61 is eilectively blocked against clockwise rotation-and thus the stepping of the 2 ratchet it will advance its wheel 85 difieren-' tially Just as for the 1 position. In the same manner the pinion 81 in the 2 and 4 positions is locked by the related wheels 65, when entries are made in the 4 and 8 positions. Where, of course, a carry is concurrent with an entry, the lower order wheel 65 is driven to advance pinion 61 in the prop r direction to add an additional unit.

In line with each cam wheel 65 is a pivoted lever 12 (Fig. 3) which is rocked to shift pairs of contacts designated 13 generally, and those associated with the first wheel 65 are identified as ll-i, those with the second wheel 13-2, etc.

As explained above, the carry pinions 61, 69 are carried by arms 68 which are pivoted on the tie rod 62. Each arm 68 has an angular slot 80 in its upper end through which a universal rod ll passes. The rod BI is supported by arms 82, one of which is shown in Figs. 2 and 3. Connected to the arm 82 is a plunger of a solenoid I which, when energized, will cause the rod 8| to move downwardly and through the cam 80 rock the arms 68 in a direction which is opposite to the direction of travel of its related cam wheel 85. This rocking of arm 68 has the effect of displacing its pinion 81 (see Fig. 6) with respect to the mutilated gear 66 and changes the carry conditions so that carry takes place during the first step of movement of the cam wheel from home position or, stated in other words, with pinion G'I shifted, carry will take place when the cam wheel moves from a low to a high position with respect to the bell crank 12, whereas with the wheel 61 in its normal position as shown in Fig. 6 carry will take place when the wheel moves from a high to a low position.

As seenin Fig. 6, when arm 68 is rocked counterclockwise, the pinion 61 and its companion pinion 89 (see Fig, 7) simply roll on their related teeth 66 and II, respectively, without changin the initial positions of the latter since they are locked through their pinions 60 and 59 to the locked ratchets 58. This shift of the carry pinions is brought about whenever subtracting operations are to be performed, and the controlling devices for doing so will be explained hereinafter in connection with the circuit diagram.

To explain the operation of entering in another way, it might be said that cam 65 has a set" and an unset position and that pinion 61 has an additive and a subtractive position, and that both the cam and the pinion may be in either of their alternate positions when an entry is made. In tabular form we then have several conditions when an entry is made.

1. Cam 65 unset"pinion 61 in "additive" position.

2. Cam 65 setpinion 81 in "additive position.

3. Cam 6! unset"pinion 61 in "subtractive position.

4. Cam SI set-pinion 61 in "subtractive position.

, As a result, a carry to the next higher order will be effected or not for these conditions as follows:

1. No carry.

2. Cam.

8. Carry.

4. No carry.

Briefly summarizing the mechanical operation of the binary accumulator, whenever any of the magnets 54 is energized, its cam wheel 85 moves one step, shifting its cam from the so-called high" to a "low position or vice versa, and each time a wheel 65 is moved two steps it will cause the next higher wheel to advance one step. When any cam wheel is in its high position, it may be said to contain an entry, and when in its low position, it may be said to be clear. The several wheels represent the several different values in the binary series, so that an entry in the first wheel represents an entry of 1', an entry in the second wheel represents an entry of 2, and entry in the third wheel represents an entry of 4 and an entry in the fourth wheel represents an entry of 8. The last wheel, which receives an entry only by carry, represents 512. Thus, where there is an entry in more than one wheel, the total entry is represented by the sum of the individual entries.

The divisor accumulator The divisor accumulator may be a duplicate of the dividend accumulator but, as will be pointed out, only one entry is made therein for a dividing operation so that the carry and overdraft parts of the mechanism are omitted. This accumulator also has contacts generally designated 13 operated similarly to the contacts 13 of the dividend accumulator. They are shown in the circuit diagram where they are identified as 13!], 13h (Fig. 1), He and 13f (Fig. 1a) and further identified by the legend divisor acc."

The quotient accumulator The quotient accumulator is the same as the dividend accumulator with the exception that it does not require the overdraft element. This accumulator also has contacts generally designated 13 operated similarly to the contacts 13 of the dividend accumulator. They are shown in the circuit diagram where they are identified as 137' and 1316 (Fig. 1 and further identified by the legend quotient acc.

The problem Before tracing circuits in detail, the problem diagrammatically set forth in Fig. 10 will be explained to make clear the principles of operation of the binary accumulator and its utilization in the performance of a dividing problem. In Fig. 10 the columns headed 1, 2, 4, 8, 16, etc., represent the orders of the dividend, divisor and quotient accumulators, into which the amount representing entries are made. In these columns are dashes and X's, the dash representing an entry in a particular position and an X representing an entry. Along the first line, dashes are shown in all positions of the quotient accumulator indicating there are no entries in any of them. The same line represents an entry in the dividend accumulator of 298 which is represented by X's in the 256, 32, 8 and 2 positions. Also, there is represented a divisor entry of 21 indicated by X's in the 16, 8, 2 and 1 positions. This first line represents the condition of the three accumulators after the dividend and divisor entries have been made.

As will be more particularly explained, in connection with the circuit diagram, the dividend accumulator has its carry pinions normally set in subtract position and the quotient accumulator has its carry pinions normally in adding position. After the initial entry has been made, so-called column shift" devices come into action to compare the dividend and divisor accumulators and determine the positions in which the highest value setting is found in each accumulator. These devices cause the selection of one of a number of so-called multiple relays which direct the entry of a multiple of the divisor into the dividend accumulator.

For the example chosen in Fig. 10, the multiple 16 times the divisor 27 is entered subtractively into the dividend accumulator and at the same time the value 16 is additively entered into the quotient accumulator. These operations are represented along the first line of the succession of lines designated step 1 in Fig. 10 and, briefly stated, consist of entering the divisor into the dividend accumulator subtractively with a lateral displacement to bring the highest valued orders of the two amounts into alignment. Since a shift of any binary representation one order to the left doubles the value, a shift of four orders to the left as in this case raises the value of the divisor so that in effect 16 times 27 or 432 is subtracted from 298, the original dividend. In Fig. 10 the carries from order to order are indicated by curves along the entry lines. An overdraft results which is evidenced by the setting of the X in the overdraft position.

In the latter part of step 1, as a result of the overdraft condition there is a shift of the dividend accumulator to add"-conditin and a shift of the quotient accumulator to subtract condition, while 8 times 27 is entered in the dividend accumulator and an 8 in the quotient accumulator. As a result, the amount in the dividend accumulator is now 82 and the quotient accumulator contains 8 signifying that 8 times the divisor has been subtracted from the original dividend during step 1.

It is to be noted that, when the overdraft occurred, the 16 multiple was not added back directly but is taken care of along with the subtraction of the next lower multiple 8; that is, since 16 times the divisor is too large, 8 times must be correct, but instead of returning the accumulator to its original setting and then subtracting 8 times the divisor, the single operation of adding 8 times the divisor after 16 times the divisor has already been subtracted results in -16+8=-8 times the divisor being subtracted.

In step 2, 4 times the divisor is now subtracted from the dividend accumulator with an accompanying additive entry of 4 into the quotient accumulator. Again, there is an overdraft condition which causes a change in condition of the two accumulators for the latter part of step 2 during which 2 times the divisor is added in the dividend accumulator while a 2 is subtracted from the quotient accumulator, resulting in the settings of 28 and in these two accumulators, respectively.

In step 3, 1 times the divisor is entered subtractively and a 1 added with the ultimate result indicated as a quotient of 11 with a remainder of 1.

Fig. 11 illustrates another problem involving dividing 340 by 17, wherein no overdraft occurs so that the multiple entries in the dividend accumulator are all subtractive and those in the quotient accumulator are all additive to obtain the quotient 20 with 0 remainder.

Fig. 12 is a further example wherein the result of 26 divided by 9 is obtained and illustrates the effect of an overdraft upon subtraction of the one times multiple of the divisor.

The circuit diagram completed in Fig. 1a from line 23, wire 50, sole-- noid 83 of the dividend accumulator, contacts R4d and 20a to line 24. This conditions the dividend accumulator for subtraction. A further circuit is also completed (Fig. 11)) from line 23, normally closed start key contacts 2|, relay contacts R222, collector ring 32 of the stepping relay, brush 33, a segment 34, contacts Sla, magnet Si of the stepping relay, relay R9 to line 24. Magnet Sl draws down its armature 29 and pawl 30 is accordingly moved down to engage the next tooth of ratchet 3!. Near the end of such down stroke, arm 29 engages and. opens contacts Sla breaking the circuit through magnets SI and R9. In Fig. 13 the line Sla designates that the contacts SI a are closed prior to closure of switch 22 and the adjoining lines indicate that upon closure of the switch 22 magnets 83Dd, Si and R9 are concurrently energized. When contacts Sla open, the circuit through magnets SI and R9 is broken and they become currentless, except for such residual magnetism as they may momentarily retain.

The spring on armature 29 now restores the same and pawl 30 moves upwardly to turn the ratchet 3| one-sixth of a revolution in a clockwise direction. The return of armature 29 is considerably slower than its down stroke, due to the fact that it now must move ratchet 3| and the brushes carried thereby. By connecting a oneway adjustable dash pot (Fig. 1b) to armature 29, the rate of return may be regulated and in Figs. 13 to 17 the distance from 0 to 60 represents the time or period of such return stroke. 1

As indicated in Fig. 13, the contacts Sla reclose at the time indicated after about 7 of movement of the commutator brushes and after brush 33 has moved off segment 34. Secured to ratchet 3| is an arm 35 upon which the brush 33 is carried and, as the ratchet turns, the brush 33 moves off the segment 34 on to an insulating section, the parts being so proportioned that this occurs before the contacts Sla reclose. Further movement of brush 33 now completes a circuit from line 23, contacts 2|, contacts R2b, collector ring 32, brush 33, segment 36, relay magnets C to line 24 (see Fig. 13).

This relay C closes a pair or contacts Ca (upnot left Fig. la) whereupon, if the dividend accumulator is clear, a circuit is completed irom line 23, contacts Ca and thence serially through contacts designated generally 13a, relay R3 to line 24. In Fig. 13 energization of relay R3 is exaggeratedly shown as occurring a short period after energization of relay C to allow for intermediate closure of contacts Ca. The contacts 130 are associated with the accumulator element cams 33 and are normally closed when the related cams 65 are in unset" position. Thus, if the dividend accumulator is clear when the main switch is closed, relay R3 becomes energized and in turn closes its contacts R3a (Fig. lb) to complete a circuit from line 23, contacts 2|, contacts R3a, relay R2, reset ke contacts 31, to line 24. This relay R2 is also shown in Fig. 13 as being energized after R3 to allow for intermediate energization of contacts R30.

As a result of energization of relay R2, the contacts R2a close setting up a holding circuit from line 23, contacts 2|, contacts R2a, relay R2 and contacts 31 to line 24, which circuit is now maintained. Energization of relay R2 also opens its contacts R212 when the holding circuit has been established, so that the circuit to the collector ring 32 is broken. Relay C is thereby deenergized and relay R3 in turn is also deenergized. These operations occur before the brush 33 reaches the next segment 34, so that when such segment is reached, the circuit through the stepping magnet SI will not be reestablished and the parts come to rest with relay R2 in energized condition. Relay R2 remains energized as indicated in Fig. 14 until the start key is depressed.

A brush 33 carried by arm 35 serves, when the arm has completed a step of movement, to electrically connect a pair of segments 33 and 40 so that, with relay contacts R2c now closed, a

circuit. is traceable from line 23, contacts 2|,

contacts R20, segment 4|), brush 38, segment 33, wire 4|, relay R5 to line 24. Relay R5 closes its contacts R5a which have no effect at this time, as it is assumed that the quotient accumulator does not contain an entry and its related contacts 13k are open.

Relay R5 also closes a pair or contacts R5b (Fig. lb) which results in energization of the dividend and divisor reset relays R6 and R1. These relays close their contacts Rio and Rla (Fig. 1) to efiect resetting of their related accumulators. It is assumed that at this time these accumulators are clear so that energization of relays R6 and R1 has no efi'ect. Also during this step there is an idle energization of relays RH and R9 (Fig. lb) through a circuit traceable from line 23, relay RI outer segment 3, brush 3. inner segment 3, contacts Rl2a, relay R3 to line 24. In Fig. 13 the timing of the several relays involved in this step are set forth.

Entry of the dividend and divis0r.-With the card ll placed in sensing position as in Fig. l and perforated with a dividend 298 and a divisor 27, the operator manually closes the start key contacts 20 (Fig. lb) which opens the connected contacts 2|. Closure of contacts 20 will energize the "read" relay RI (Fig. lb) which closes its contacts R|a and Rlb (Fig. 1), thereby completing parallel circuits from line 23, the common contact bar l4. perforations representmg 298 in the dividend field of the card, brushes l2, wires 25, contacts Ria, the dividend accumulator magnets 54 in the 2, 8, 32 and 256 order positions, wire 26 to line 24.

Concurrently, parallel circuits are completed from line 23, the common contact bar l4, pertoratlons representing 27 in the divisor held of the card, brushes l3, contacts Ric, wires 21, the divisor accumulator magnets 54 in the 1, 2, 8 and 16 order positions, wire 28 to line 24. Energization of these several magnets 54 causes retraction of their related pawls 51 (Fig. 5) so that upon release of the start key and deenergization of relay RI, magnets 54 become deenergized and the actuating springs 56 (Fig. 5) advance the selected orders to their set" positions to effect entries in the dividend and divisor accumulators as indicated on the line designated enter in Fig. Ill and at the time indicated in Fi 14.

Depression of the start key also opens contacts 20a (Fig. 1a) to deenergize the solenoid 83 during the initial dividend entry so such entry is additive. The parts are so proportioned that relay Rl (Fig. 1b) deenergizes the magnets 54 before contacts 20a reclose, so that solenoid 83 is not reenergized until the dividend has been fully entered.

Opening of the start key contacts 2| (Fig. 1b) has broken the holding circuit of relay R2 so its contacts return to the positions shown in Fig. 1b, deenergizing relay R5. When the start key is released, the dividend and divisor accumulators become set as stated. Reclosure of contacts 2| now completes the circuit already traced to energize the relay R3 and the stepping magnet S| which draws pawl 30 down and opens contacts Sla, while the factors are being entered in the accumulators (see Fig. 14)

Comparing circuits.0n the upstroke of pawl 30, brush 33 moves of! segment 34 as before and the circuit traced above is completed to energize the comparing relay C. At this time, however, the closure of contacts Ca (Fig. 1a) will not complete the series circuit previously traced, inasmuch as several of the contacts 13a are open as a result of setting the dividend amount in the related accumulator, so that relay R3 does not become energized.

Instead, a so-called comparing circuit is now completed upon closure of contacts Ca, which ascertains the location of the highest accumulator orders of the dividend and divisor accumulators in which a setting is now present. For the example chosen, this circuit is traceable from line 23 (Fig. 1a), contacts Ca, contacts (now closed) in the 256 value order, wire 42, relay CS related to the 256 value order to line 24.

A parallel circuit is also traceabl from line 23, contacts Ca (now closed), serially through the contacts |3e of the four highest orders of the divisor accumulator, contacts 13f (now closed) of the 16 value order, wire 43, to the connected one of a group of wires 44, contacts CSa, connected wire of a group of wires 45, wire 46, relay MR in the 16 value order. a relay R8, to line 24. To facilitate tracing these circuits, they are emphasized by heavy lilies.

The MR relays are designated as "multiple relays and their function is to control the entry or a divisior multiple whose value is determined by the particular MR relay energized. Thus, the energization of the It value relay MR will cause 16 times the divisor to be entered into the dividend accumulator.

Entering the divisor muZtiple.While the brush 33 is still traversing the segment 36 (Fig. 1b) and thus maintaining relay C energized, so that the selected relays CS and MR also remain energized, the contacts MRa (Fig. 1) related to the 16 value relay MR are closed. Upon such closure the circuits emphasized by heavy lines in Fi 1 are completed from line 23, wire 41 now closed, contacts 139 in the 16, 8, 2 and 1 orders of the divisor accumulator, group of wires 43, contacts MRa of the 16 value relay MR, group of wires 49, the 256, 128, 32 and 16 order magnets 54 of the dividend accumulator, wire 26 to line 24. Thus, the dividend accumulator magnets 54 are energized in accordance with the 16 multiple of the divisor as indicated in Fig. as step 1 opposite the legend Subt."

Entering the quotient value-Concurrently with completion of the foregoing circuits, the value 16 is entered into the quotient accumulator. A pair of contacts MRb (Fig. 1b) closed by the 16 value relay MR will complete a circuit from line 23, contacts MRb, the 16 value magnet 54 of the quotient accumulator to line 24. This circuit is also emphasized by heavy lines.

When brush 33 moves of! the segment 36 on to the insulating portion during the latter part of the step, the several relay and accumulator magnet circuit become deenergized and at such time the accumulator wheels advance under the influence of their springs. Specifically, when brush 33 leaves segment 36, relay C is deenergized, releasing relay CS, which in turn releases MR which is followed by release of magnets 54 in the dividend and quotient accumulators. Upon said last release, the accumulators advance under the influence of their springs 56 (Fig. 3) which have a sufilcient tension to effect rapid stepping of the accumulator ratchets one tooth space. In Fig. 14 this sequential operation is indicated in an exaggerated manner for purposes of greater clarity.

Subtraction control circuits-The entering into the dividend accumulator is to be subtractive and the entering into the quotient accumulator is to be additive. As explained, both accumulators normally have their carry devices in additive carry position, so it is only necessary to shift that of the dividend accumulator. This is effected as follows: When the main switch 22 (Fig. 1) is closed and current is on lines 23, 24, a circuit is immediately traceable from line 23 (Fig. 1a), wire 50, solenoid 83 of the dividend accumulator, contacts R4d, to line 24. As explained, the operation of the start key will open contacts 23a (Fig. 1a) to deenergize magnet 33 of the dividend accumulator, and as indicated in Fig. 14 after release of the start key this magnet 33 is again energized. Thus, the carry pinions 81 of this accumulator are normally in subtractive position with the result that, when the 16 multiple of the divisor is entered during the first part of step 1, there is a resulting overdraft which causes closure of the contacts 13b (Fig. 1a) in this highest order of the dividend accumulator. A circuit is thereupon traceable from line 23 (Fig. 1a) contacts 13b in the overdraft order, relay R4 to line 24, so that relay R4 will remain energized until contacts 13b open again. Relay R4 opens its contacts R411 and closes contacts R4e, thus reversing the condition of the subtraction control solenoids 33. Thus, the quotient accumulator is now conditioned for subtraction and the dividend accumulator for addition. 'Relay R4 also closes its contacts R422 (Fig. 1a).

Overd aft controlled entry-The effect of an overdraft is to cause the next lower multiple of the divisor to be immediately entered into the dividend accumulator additively, and such entry will necessarily result in a positive value in the dividend accumulator. Thus, as indicated in Fig,

10 in step 1 along the line designated add. the l 8 times multiple of 27 is added resulting in the value 82 being represented in the dividend accumulator. Considering the circuits involved, it was explained above that when a selected MR relay ,(Fig. 1a) is energized, a relay R3 is energized in series therewith. Thus, the 16 relay 34R and the 16 relay R3 were both energized with the latter closing a pair or related contacts R30 and R3b and opening a pair of contacts R3c. Contacts R3a established a holding circuit for the relay R3 traceable from line 23, contacts R311, a relay RIZ, contacts B31: in the 16 value position, the related relay R3 to line 24. This holding circuit is maintained until contacts Rla open through energization of relay R3, which relay is wired in series with the stepping relay magnet SI (Fig. 1b). Accordingly, relay R3 is energized at the end of the step.

Upon closure of overdraft contacts "b (Fig. 1a) and resultant closure of relay contacts R42), a circuit is traceable for the problem of Fig. 10, from line 23, wire 50, contacts R4b, contacts Me in series in the 256, 128, 64 and 32 positions to contacts R3!) in the 16 position (now closed), the 8 relay MR, relay R3 to line 24.

Energization of the 8 relay MR closes the contacts MRa in the 8 position of Fig. 1 completing circuits through the contacts of the divisor accumulator to enter 8 times the divisor into the dividend accumulator by energizing the magnets 54 thereof in the 128, 64, 16 and 8 positions. The selected magnets 54 remain energized until the end of step 1 when relay R3 is energized (Fig. 1b) opening its contacts R3a (Fig. 1a) to deenergize the MR and R3 relays. As a result, the dividend accumulator wheels advance additively and the overdraft contacts 13b open.

The 8 relay MR also closes its MRb contacts (Fig. 1b) to efiect the subtractive entry of 8 into the quotient accumulator. At the end of step 1, the dividend accumulator contains the amount 82, the quotient accumulator contains the amount 8 and the operations of step 1 are repeated with the initial energization of the stepping relay magnet SI.

Step 2 of Fig. 10.Upon commencement of this step, the movement or brush 33 of! segment 34 deenergizes relay R9 so its contacts R3a again close. In the same manner as described for step 1, relay C (Fig. 1b) is energized at the beginning of the step closing its contacts Ca (Fig. la) and keeping them closed for about one-half the step, during which time a circuit is completed to energize the 54 relay CS, since this is the highest position of the remainder 32. This circuit is traceable from line 23, contacts Ca, contacts 13m in the 256 and 128 positions, contacts lie in the 64 position, relay CS in the 64 position to line 24. Concurrently, a circuit is also completed to energize the 4 relay MR and the 4 relay R3 which latter relay is held. This circuit is traceable from line 23, contacts Ca, contacts lie in the four highest orders, contacts 13] in the 64 order position, wire 43, contacts CSa of the 64 order MR relay, appropriate wire 45, 4 relay MR and R3 to line 24.

The 4 relay MR closes its contacts MRa (Fig. 1) and MRb (Fig. 11)) so that the dividend magnets 54 become energized in accordance with 4 times the divisor 27, and the quotient magnets 54 become energized in accordance with the value 4. When contacts Ca open, deenergizing the CS and MR relays, actual entries take place to subtract in the dividend accumulator and add in thequotientaccinnulator. Thisagainresultsin 'an overdraft so that contacts lib close, energizing relay R4 (Fig. 1a) which reverses the addin: and subtracting condition of the dividend and miotient accumulators and completes a circuit through its contacts Rlb to energize the 2 relay IR. This circuit is traceable from line H, wire ll, contacts Rib, contacts Rio, in the six right hand positions, contacts Rib in the 4 position, relays HR and RI in the 2 position to line 24.

As a result, 2 thnes the divisor is additively entered in the dividend accumulator and the value 2 is subtractively entered in the quotient accumulator during the latter part of step 2 at the end oi which relay R! is energized to deenergiae the RI relays and the overdraft contactallb assn open- B'tep .1 of l'ig. 10.At the beginning of this step, when contacts Ca close, the 16 relay CS b energised since the 16 order is the highest dividend order now set, and through its contacts 08 the 1 relay MR is energized together with the related RI relay, which latter is held energind. 1 times the divisor is accordingly subtracted from the dividend accumulator while a l is added in the quotient accumulator. The actual entry takes place when contacts Ca open, but this time there, is no overdraft so that, during the remainder of the step, no additional entries are made and the relay R8 is deenergized at the end of the step as before upon energization of relay RI.

Step 4 of Pia. Ill-At the beginning of this step, the dividend accumulator stands at 1 and the divisor accumulator at 21. When contacts Cd close. the l relay CS is energized, but it will be found that no circuits are completed to the IR relays. The arrangement of the circuit connections between the contacts lie and 13! (Fig. 1a) is such that, when the divisor amount has a setting in a position greater than the highest set position in the dividend accumulator, no MR relay is energized. Accordingly, also no RI relay is energized.

Near the end of the step, a third brush desig rated in Fig. lb and carried by arm II bridges a pair of contact segments 8 so that a circuit is completed which is traceable from line 23, relay Rli, outer segment 6, brush 9, inner segment I, relay contacts Rlia, relay Rl, to line 2|. The contacts Rita are controlled by relay RI! which is in the holding circuit of the RI relays (Fig. is) so that, if any RI relay is energized, the contacts Rlic are opened and held open until the end of the step, i. e. until after brush 8 has passed the segments 0. This has been the case in the preceding steps. In the present step, however, the circuit is completed with the resultant tion of relay Rll which closes its contacts Riia to energize relay R2 which in turn sets up the holding circuit already traced and opens its contacts Rib to cut the current supply to ring 32, whereby when the step is finally ended magnet Bl will not become energized and stepping of the relay is terminated at that point.

Recording the quotient.Relay R2 has also closed its contacts Ric, so that when brush it bridges segments it, it at the end of the step, the circuit is completed to energize relay RI closing contacts R50. Since the quotient contacts 13k in the 8, 2 and 1 positions are now closed or set," circuits are completed through the related punch magnets I which, as diagrammatically shown in Fig. l. urge punches 6 to perforate the quotient back in the card ll.

At the same time closure of relay contacts Rlb (Fig. lb) has energized the reset relays R6 and R! which close their contacts Rta and Rio in Fig. 1, so that circuits are completed through the magnets I of the dividend and divisor accumulawrs in positions wherein the related contacts lid and 13h are in set position.

Relay R6 closes a pair of contacts Ric (Fig. 1b) to energize reset relay Rll which in turn closes its contacts Rlla to complete circuits to the magnets 54 of the quotient accumulator whose related contacts 13:! are in closed position. It will be observed that with the stepping relay inactive in home position, relay Rl remains energized and the reset relays R6 and R1 and RIG, as well as the selected magnets It, will also be in energized condition. The operator may then .press the reset key to open contacts 31 (Fig. 1b)

which breaks the holding circuit of relay RI, opening its contacts Ric whereupon the aforesaid relays and magnets deenergize to enable the overdraft occurs and the dividend reduces to zero.

three accumulators to advance to zero position and the punches to withdraw from the card.

It is necessary at this time to condition the quotient accumulator for subtraction. For this purpose, the reset key closes a pair of contacts 31a (Fig. 1a) to energize the carry control solenoid I! of the quotient accumulator, that of the dividend accumulator already being energized 1 at the end of this step. It is to be noted that before the end of the step, when brush 0 bridges segments 8, relay RI 1 is energized inasmuch as contacts Rlia are now closed. This has no elffeet at this time, since relay R2 is already energized andheld.

The first card is now removed and another is located in its place. From this point operations continue as explained under the heading "Entry of the dividend and divisor.

The problem of Fig. 11.In this example no When contacts Ca first close (Fig. 1a), the 256 relay CS is energized and through its contacts CSa the 16 relay MB is energized resulting in -the subtractive entry of 16 times the divisor.

Since this does not result in an overdraft, no further entriesoccur during step 1 and, when contacts Ca again close in step 2, the 64 relay CS is energized andv through its CSa contacts the 4 relay MR is energized, resulting in subtraction of 4 times the divisor. Concurrently, during the first and second steps 16 and 4 are added in the quotient accumulator.

Near the end of the second step, following the multiple entry, the dividend accumulator will stand at zero and, as a result, when contacts Ca close in the next following step relay R3 is energized through the series circuit through the its contacts to close its contacts Rla (Fig. 1b). This energizw relay R2 and interrupts further stepping. From this point operations proceed as set forth under the heading Recording th duo. tient.

The problem of Fig. 12.This example illustrates a condition wherein at one stage the divisor and dividend both have their highest set position equal in value, but thedivisor is the greater number. Thus, for the problem of 28 divided by 9 we note that, after the first entry of 2 times the divisor, the dividend accumulator stands at 8. In step 2, the 8 relay CS is energized through familiar circuits and the 1 relay MR is also energized to effect a subtraction of 1 times the divisor, which results in an overdraft. Energization of the 1 relay MR has been accompanied by energization of the related RI relay which is thus held with its R811 and Rlb contacts closed at the time the overdraft contacts 'llb close.

At such time a circuit is completed from line 23, wire 50 (Fig. la), contacts Rlb (now closed), the relay contacts R80, contacts Rlb in the 1 position, relay R"), the 1 relay MR, the 1 relay R8 to line 24. Thus, the 1 times relay MR is again energized and 1 times the divisor is now additively entered in the dividend accumulator while a 1 is subtractively entered in the quotient accumulator. The relay Rlil closes a pair of contacts Rina (Fig. 1b), so that near the end of the stop when brush 9 bridges segments 8, a circuit is completed from line 23, relay RI l, brush 9 and segments 8, contacts Rilla, relay R9 to line 24. Relay R9 opens its contacts Rla (Fig. la) to demergize the MR relay and allow the accumulator elements to receive the entry, during which the overdraft contacts open and the dividend and quotient accumulator stand at 8 and 2, respectively. Relay Rll causes energization of relay R2 so that, at the end of the step, magnet SI is not reenergized and punch relay R is energized to control the punch magnets 1, as explained.

With this arrangement set forth. only the whole part of the quotient is punched but it is apparent that by providing contacts on the divill.

dend accumulator wired to further punch magnets 1, the remainder may also be punched, if desired.

While there have been shown and described and pointed out the fundamental novel features of the invention as applied to a single modification, it will be understood that various omissions and substitutions and changes in the form and details of the deviceillustrated and in its operation may be made by those skilled in the art without departing from the spirit of the invention. It is the intention therefore to be limited only as indicated by the scope of the following claims.

What is claimed is:

1. In a dividing machine, a binary dividend accumulator having binary ordered elements conditionable for addition or subtraction, and being normally conditioned for subtraction, conditioning means therefor, a binary divisor entry receiving means having binary ordered elements, means for entering dividend and divisor values in accordance with the binary system of notation. readout devices for the divisor receiving means, column shift mechanism intermediate the divisor readout devices and the entering means of the dividend accumulator, comparing means for ascertaining the elements of the dividend accumulator and the divisor receiving means containing the highest terms of the two factors,

means under control of said comparing meam for adjusting said column shift mechanism, said readout devices and conditioning means effecting multiple of the divisor the divisor value.

2. In a dividing machine, a binary dividend ac cumulator having binary ordered elements conditionable for addition or subtraction, and being normally conditioned for subtraction, a binary divisor entry receiving means having binary ordered elements, means for entering dividend and divisor values in accordance with the binary system of notation, readout devices for the divisor receiving means, column shift mechanism intermediate the divisor readout devices and the entering means of the dividend accumulator, comparing means for ascertaining the elements of the dividend accumulator and the divisor receiving means containing the highest terms of the two factors, means under control of said comparing means for adjusting said column shift mechanism, said readout devices effecting subtraction of a binary multiple of the divisor from the dividend accumulator through said column shift mechanism, an overdraft device controlled by said dividend accumulator, and means controlled by said overdraft device when the multiple of the divisor subtracted is greater than the dividend for effecting addition of the next lower blnary multiple of the divisor in the dividend accumulator.

3. In a dividing machine, a binary dividend accumulator having binary ordered elements conditionable for addition or subtraction. and being normally conditioned for subtraction, a binary divisor entry receiving means having binary ordered elements, means for entering dividend and divisor values in accordance with the binary system of notation, readout devices for the divisor receiving means. column shift mechanism intermediate the divisor readout devices and the entering means of the dividend accumulator, comparing means for ascertaining the elements of the dividend accumulator and the divisor receiving means containing th highest terms of the two factors, means under control of said comparing means for adiustng said column shift mechanism, said readout devices effecting subtraction of a binary multiple of the divisor from the dividend accumulator through said column shift mechanism. an overdraft device controlled by said dividend accumulator, and means controlled by said overdraft device when the multiple of the divisor subtracted is greater than tlm dividend for conditioning said dividend accumulater for addition and readjusting said column shift mechanism to effect addition of the next lower binary multiple of the divisor in the dividend accumulator.

4. In a dividing machine, a binary accumulator, means for entering a dividend amount therein, conditioning means for causing the accumulator to eifect addition or subtraction. an overdraft device controlled by the accumulator. divisor entering means controlled to enter a divisor multiple in said accumulator, said accumulator being conditioned to receive said divisor subtractively, and means controlled by said overdraft device, when said subtractive entry results in an overdraft for causing said divisor entering means to enter one-half the divisor multiple and for causing said conditioning means to condition the accumulator to receive said entry additively.

5. In a dividing machine, a binary accumulator settable to represent a dividend, said accumulator being conditionable to effect additive or subh'active operations, means settable to represent a divisor. comparing means jointly controlled by said accumulator and said divisor settable means, means including the settable means for eifecting repeated entry of the divisor into said accumulator, and means controlled by said comparing means for directing said repeated entries into different positions of the accumulator for each repeated entry to cause successive binary multipia of the divisor to be entered.

6. The invention set forth in claim in which an overdraft device is included in said accumulator, and means controlled by said overdraft device for selectively causing said divisor multiple entries to be elected additively or subtractively.

'I. In a dividing machine, a binary accumulator having ordered elements, a settable device having similarly ordered elements, the elements of both the accumulator and the device being settable to represent, respectively, a dividend and a divisor expressed in the binary system of notation, comparing means for ascertaining the element of the accumulator and of the settable device containing the highest valued binary representation, operating means therefor. a series of multiple selecting relays, each comprising devices for causing a diflerent binary multiple of the divisor to be entered under control of the device in the accumulator, and means controlled by said comparing means for selecting and rendering eifective the multiple relay whose related multiple of the highest term of the divisor is of a magnitude equal to that of the dividend in the highest binary representing order.

8. The invention set forth in claim 7 in which the accumulator is aranged to receive the transferred multiples subtractively, an overdraft device in the accumulator, means controlled by said overdraft device, when a transferred multiple causes an overdraft, for causing operation of the relay of the next lower binary multiple independently of said comparing means.

ing the repeated operation of the comparing means.

10. In a dividing machine, an accumulator settable to represent a dividend, a device settable to represent a divisor, both said settings being in accordance with the binary system of notation, means for comparing said settings, column shift devices, transferring means including said column shift devices controlled by said comparing means to subtractively transfer a binary multiple of the divisor under control of the divisor device to the accumulator, means for causing repeated operation of said comparing and transferring means, said comparing means causing a difierent lower binary multiple to be transferred for each repeated operation, and means controlled by said accumulator when the dividend is reduced to zero for terminating said repeated operations.

11. In a dividing machine, an accumulator settable to represent a dividend, a device settable to represent a divisor, both said settngs being in accordance with the binary system of notation, means for comparing said settings, column shift devices, transferring means including said column shift devices controlled by said comparing means to subtractively transfer a binary multiple of the divisor under control of the divisor device to theaccumulator, means for causing repeated operation of said comparing and transferring means, said comparing means causing a different lower binary multiple to be transferred for each repeated operation, and means controlled by said comparing means when the one times multiple of the divisor has been transferred for terminating said repeated operations.

12. The invention set forth in claim 10 in which a quotient accumulator is provided. and means controlled by said comparing means for adding therein quotient values corresponding to the multiples transferred.

WILLIAM LANG.

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