US2240797A - Calculating machine - Google Patents

Description

May 6, 1941. I w. J. PA SINSKI CALCULATING MACHINE Filed 001:. 30, 1935 4 Sheets-Slight 1 INVENTOR ah'erJ. Pas/hale;-

ME V ATTORN Ys May 6, 1941. w. J. PASINSKI CALCULATING MACHINE 4 Sheets-Shut 2 INVENTOR Wd/Ier J ATTORNEYfS m MW M y 6, 1941. w. J. PASINSKI 2,240,797

CALCULATING MACHINE- Filed Oct. 30, 1935 4 Sheets-Sheet 3 INVENTOR EA/amp a. BIS/"5A; M @JM ATTORNEYS W. J. PASINSKI CALCULATING MACHINE May 6, 1941.

Filed Oct. 30, 1935 4 Sheets-Sheet 4 7 I INVENTOR lfer uf Pas/nah ATroRuvg Patented May 6,v 1941 CALOULATIN G MAQHINE Walter J. Pasinski, Howell, Mich., assignor to Burroughs Adding Machine Company, Detroit, Mlch.', a corporation of Michigan Application October 30, 1935, Serial No. 47,368

4 Claims.

This invention relates to a calculating machine. It is concerned particularly with an amount-key-responsive type of machine sometimes called an "automatic calculator. Such a machine is disclosed in Pasinski No. 1,909,714 and the present invention'is directed to improvements in this machine.

Machines of this type have heretofore been used mainly for performing addition. It has been possible to perform subtraction by depressing keys corresponding to the complement of the subtrahend, which resulted in performing subtraction by a process of complemental addition. However, the selection of keys corresponding to the complement of the subtrahend increases the work required of the operator and requires that two different digitsbe inscribed on the top of each key top. The present invention. concerns an improvement in this type of calculator that enables the operator to enter the subtrahend in the same manner as if it were to be added and, then, by merely depressing a key to subtract said subtrahend. I

Prior machines of this type have also had two registers with provisions for transferring the total from one register to the other, but this transfer operation has been limited to transferring totals in a positive direction. The present invention concerns an improvement whereby a diflve or subtractive'ly.

It is also an object of this invention to provide multiple and necessary mechanisms whereby otals may be, transferred subtractivelyin a key mpomrive calculator in which different columns of the machine may be selected as the units column.

Other obiects and their resultant advantages ill be apparent to those skilled in the art from t e following description when read in connecfi m w th the drawin s in which: Fi .1 is a ri ht side elevation of a calculating machine embodyin the principles of this inven tibn, the coverind certain parts'being removed depressed.

and broken away to show the novel features, all

in normal position;

Fig. 2 is a right side elevation illustrating more particularly the operating or control keys all in normal position;

Fig. 2 is a fragmentary detail of a portion of the clutch;

Fig. 3 is an enlarged right side elevation of the front portion of the machine illustrating a subtraction operation with the digit 3 in the front register and being transferred to the rear register as the true complement I;

Fig. 4 is an enlarged side elevation of an index plate such as is used in all but the units column;

Fig. 5 is a view similar to Fig. 4 but illustrating an index plate used in the units column;

Fig. 6 is a fragmentary right side elevation illustrating certain conditions with the decimal transfer cut-out key depressed: and

Fig. '7 is an enlarged fragmentary detail of the index plate and associated parts used in the fourth column to transfer a true complement when the first three columns to the right thereof are blocked against transfers by depression of the decimal transfer cut-out key.

' The invention is shown applied to the Burroughs automatic electric calculator which has been on the market for some time and which is disclosed in Pasinski No. 1,909,714. This machine will be described briefly, reference being made to said Pasinski patent for further details.

General features The calculator has a plurality of banks of amount keys Ill (Fig. 1) whose stems are slidward to enter items. The key stems have lateral rojections ll that are located so that, when a key is depressed, its lug is positioned in the path of a projection IS on. an index bar H to limit the movement of the bar to a distance correspondin to the digital value of the key It will be understood that the bars l1 and have a plurality of projections i8 and that th e is a bar for each bank of keys.

The lower end of each key stem is positioned to move into a slot ll formed in a slide I! which is urged forward by a spring 2|, there being a slide Is for each bank of keys. The arrangem t is such that. when a key is depressed, it rm es into its slot i8 and thereby moves the s ide is rearward for the purpose of starting the motor. The slide I9 is temporarily latched in rearward position by a latch 33 (Fig. 1) as described in said Pasinski patent and, when so latched, it holds the depressed key in depressed position.

The driving motor M is a normally inactive electric motor controlled by a switch 23 in the motor circuit. Normally, this switch is open, being held in open position by a bail 23 spring urged to the left in Fig. 1 by a spring 23". Each slide I 9, which is moved to the rear whenever a key in its bank is depressed, has a downwardly projecting finger 22 (Fig. 1) positioned to engage the bail 23 so that, when any amount key is depressed in any bank, the motor switch 23 will be closed and the motor started.

The motor M drives a main shaft 29 through suitable gears, not shown, but disclosed in detail in said Pasinski patent. This shaft extends across the width of the machine and fixed to it is a series of toothed disks 3|, there being a disk for each bank of the machine. When the motor is operated, these disks are r ated. counter-clockwise as viewed in Fig. 1. The dex: bar ll of each bank is connected to its toothed disk 3| by means of a pawl 32, which is carried by an arm 32 connected to the index bar l1, said arms being pivoted on shaft 29. The pawl 32 normally is held ineffective by a pivoted member 34 but, when the slide I9 01' any bank is moved rearward, it rocks its member 3| counterclockwise which releases its pawl 32. Said pawl 32 then engages its toothed disk 3! and the disk moves the corresponding arm 32" counterclockwise to move the index bar I? forward. The forward movement of index bar I! continues until one of its projections I8 strikes the lug ll on the depressed key. When this occurs a relative movement between the arm 32'- and the index bar I! takes place which rocks a member 35 that disengages the pawl 32 and releases the latch 33. Disengagement of pawl 32 releases the index bar I! which is thereupon moved rearward to normal by its spring 36 (Fig. 1) connected to the lower end of its arm 32*. Release of latch 33 permits slide is to be returned forward to normal by its spring 2] which results in opening the motor circuit and releasing the de ressed amount key.

The forward end of each index bar I! is pivotally connected to a toothed actuator 40 ivoted at 4 I This actuator meshes with a gear ll carrying a pawl 42 (Fig. 1). The pawl 42 is arranged so that when gear II is rotated clockwise. as it is by forward movement of the index bar l1. it slips over studs 43 on a gear 44 but. when the ear ll is rotated counterclockwise by the return movement of index bar '1. said pawl engages one of said studs 43 and r tates the gear 44 counterclockwise. The gear I is in constant mesh with the pinions of the front re istering mechanism.

The front registering mechanism, which is pos tioned at the front of the keyboard as shown in Fi 1. comprises a series of register pinions 41, there being a pinion and set of gears ll-fl for each bank of the machine. These register pinions are visible throu h a sight opening 43 in the casing 49. A suitable tens-transfer mechanism is provided. For further details of the registering mechanism, reference is made to said Pas nski Patent No. 1,909,714 and to (300011 1,128.679.

Upon depression of an amount key, the slide IS in the bank in which the key is depressed is moved rearward to thereby start the motor which immediately moves the corresponding index bar I! forward to differential position. The index bar is then automatically disconnected and the motor switch is opened. No actuation of the register occurs during the forward movement of the index bar I! but, upon the return movement of the bar, the corresponding register pinion I! is moved in an additive direction an amount corresponding to the distance the index bar was moved forward, which amount is, of course, determined'by the digital value of the key depressed.

The above operation takes place almost instantly. When an operator depresses a key, the motor starts, the parts are connected and immediately operated, said parts are then disconnected, the motor stopped, and the amount registered in the pinion within a fraction of a second.

The front register may be cleared by depressing a clearing key FR (Fig. 2) which causes the motor to move a member 35 shown in dotted lines in Fig. 2 to thereby operate the clearing mechanism. It has not been considered necessary to illustrate and describe this mechanism in the present case, reference being made to British Patents Nos. 450,533 and 450,591 which disclose it in detail.

The above should be sufficient for a general understanding of the machine, reference being made to said Pasinski patent for further details.

Rear Registering Mechanism Another registering mechanism is located at the rear of the keyboard, as shown in Fig. 1, which mechanism may be called the rear register or the total-storing" register. In subtract operations, it may also be viewed as the main register.

This registering mechanism comprises a plurality of register pinions 5| and it is of exactly the same type as the front register heretofore described, being provided with suitable tenstransfer mechanism. It is indexed by actuators 53 pivoted at 34, said actuators engaging pinions 55 for driving the register pinions 5|. The actuators 33 are indexed under control of mechanism governed by the front register, which mechanism will first be described in connection with transferring amounts from the front to the rear register additively.

Amount Transfers-Positive Provision is made for quickly and easily transferring amounts from the front register, which may either be individual items or an accumulation of items, to the rear register by the mere depression of a single transfer key TR (Fig. 2). The mechanism for accomplishing this result additively is substantially that of my copending application Serial No. 694,550, filed October 21, 1933, disclosed in British Patents Nos. 450,533 and 450,591, and reference may be had to said patents for any details not described herein.

Each of the front register pinions 41 is provided with a snail cam 8| (Fig. 1) having a uniform rise to correspond with the digital values of the pinion. A stud 62 on the upper end of a lever 34 pivoted at 83 is urged into engagement with the edge of this cam by a spring 86 that urges the lever 34 clockwise. When a register pinion is in 0" position as shown in Fig. 1, the stud 62 engages the low point of the snail cam 3|. As the register-pinion moves away from "0" the cam II, engaging the stud 62, rocks the lever 33 counterclockwise about its pivot 65.

Pivotally connected to the lower end of each lever 64 at 61 is a link 68 having an upwardly extending portion provided with a cam slot 89 best shown in Fig. 3. Positioned in the cam slot 89 is a stud I on an arm 1| forming a portion of a yoke I2, pivoted at I3 and urged counterclockwise (Fig. 3) by a spring 12. The yoke I2 has an extension 14 forming an index member or sector provided with two sets of stepped shoulders I and I6. For the present only the stepped shoulders I5 will be referred to in the description. It is to be understood that there is an index member I4 with associated parts for each order of the machine and, from the above description it will be clear that these index members continuously reflect the amount in the front register; that is, at all times they are positioned in accordance with the positions of the snail cams on the pinions 41 of the front register.

Positioned for engagement with the stepped shoulders I5 in each order is a lug I'I formed on the forward end of a differential link or member I8 (Fig. 1) slidably supported at its front end on a stud IB This link is somewhat irregularly shaped and extends rearward and pward to where it is pivotally connected at I9 lg. 1) to a downwardly extending lever 89 pivoted on the shaft 54. The upper end of the lever 88 is connected to the actuator 53 at 88 and said lever 80 together with its actuator is urged counterclockwise in Fig. 1 by a spring 56, the lever 80 limiting against a bail 9| that engages the lower ends of the levers. The springs 59 thus urge the actuators 53 and levers 80 counterclockwise (Fig. 1) and, since the differential links 18 are connected to the lower ends of the levers 80, the links are urged rearward. However, normally, these par-ts cannot move because of the bail 8|.

The ball 81 is moved rearward by the motor at the option of the operator and under the control of a transfer key TR (Fig. 2) to enable the differential links I8 to move to differential positions. Referring to Fig. 2, the bail BI is carried by the lower ends of a pair of arms 8| a pivoted on the shaft 54 and urged counterclockwise by a spring 8|". One of the arms 8| carries a stud BI engaged by the slotted end of the upper arm of a bell crank 84 pivoted at 84 The lower 'arm of this bell crank carries a stud 84 engaging the edge of a cam 83 that is connected through a clutch to the main drive shaft 29, which shaft, it will be recalled, is rotated counterclockwise in Fig. 2 when the motor operates. In the normal position of the parts,.the stud 84 contacts the hi h portion of the cam 83 and the bell crank 84 is held in the position of Fig 2. When the'cam 83 is rotated, the stud 84 follows the cam edge under the urge of spring 8| acting through parts 8P 8| and 84 and, as the lower portion of the cam comes into position, the bail 8| is moved rearward, thereby releasing the actuators 53 and the links I8 for movement to differential positions by the springs 56 (Fig. 1). This movement of the actuators 53 does not enter an amount in the register pinions but, as the high point of cam 83 comes around to position, the bell crank 84 is rocked counterclockwise to move the bail 8| forward to normal and said bail moves the actuators clockwise to normal during which movement the indexed amount is entered in the register pinions 5| and the differential links I8 are returned forward to normal.

The transfer key TR is carried on a key stem 86 (Fig. 2) slidably mounted in the keyboard. Pivotally connected at I90 to this key stem is one arm of a bell crank 81 pivoted at 88 to a frame plate of the machine. The lower arm of this bell crank is connected to a link 89 that extends rearward where it is slidably supported on a stud 9|, said link being urged rearward by a spring 98. The rear end of the link 89 has a lateral lug 92 normally extending over the end of the lower arm of the bell crank 84 to prevent movement of said bell crank unless-the transfer key TR is depressed. Thus, even though the cam 83 may be rotated when the drive shaft rotates under control of the clearing keys described later, the bell crank 84 will not move unless the link 89 is moved forward by depression of the transfer key TR or the subtract key later described. When the transfer key TR is depressed, the bell crank 81 is rocked clockwise to move the link 89 forward to release the bell crank 84.

Depression of the transfer key TR also starts the motor and engages a clutch for rotating the cam 83. Referring again to Fig. 2, the stud I00 which connects the bell crank 81 to the stem 86 of the key TR, projects suiiiciently to engage a cam slot I01 in a control slide slidably mounted on studs 88 carried by one of the plates of the keyboard, said slide being urged rearward by a spring 88. The cam solt IN is shaped so that, when the key TR is depressed, the slide 95 will be moved forward where it will be temporarily held by a latch I05 having a lug that engages a notch in the slide.

To start the motor, 'the control slide 95 has a cam slot 98 (Fig 2) in which is positioned a stud 91 carried by an arm 98 pivoted at 99 to a stationary frame plate. The cam slot 96 is shaped so that, when the slide 95 is moved forward, the arm 98 will be rocked clockwise, The rear end of arm 98 has a hooked end I02 positioned over a stud M3 carried by an arm I84 forming a part of the bail frame 23 controlling the motor switch 26. When the arm 98 is rocked clockwise by forward movement of control slide 95, its hooked end I02 engages stud I03 and cams the arm I04 counterclockwise to thereby close the motor switch to start the motor. The hooked end I02 moves over the stud and holds the switch closed until the control slide 95 is moved rearward again.

Forward movement of the slide 95 also engages the clutch heretofore mentioned which will now be described. The rear end of the slide 95' is pivotally connected at I06 to the upper end of a lever I01 pivoted at I08 to a stationary frame plate. Pivotally connected to :the arm I81 is a pawl I09 urged counterclockwise in Fig. 2 by a spring I09. The forward end of the pawl I09 has a shoulder IIO positioned in front of 9. lug III on a latch III pivoted at III and urged counterclockwise in Fig, 1 by a spring III. The lower end of the latch III has a hooked end normally engaging a shoulder on a clutch controlling member Il2 urged counterclockwise in Fig, 2 by a spring H3. The ciuitch controlling member IIZ is operatively connected to a semicircular connecting dog I I5 rotatably mounted in a member II4 (Figs. 2 and 2). The connection is such that, when the member H2 is rocked counterclockwise (Fig. 2) by its spring II3, the dog H5 is rotated to engage a notch in the edge of a driving clutch disk II4 connected to the main shaft 29. Thedog together with member I I4 is then rotated by the shaft 29 and the member II4, being connected to cam 83, rotates said cam. This clutch and its controls are described and illustrated in more detail in said previously mentioned British Patent No. 450,533. The arrangement is such that, when the latch II! is released, the clutch is engaged and the cam 83 rotated.

The rotation of the clutch is limited to one revolution no matter what the nature of the depression of the transfer key TR. The stud on the clutch member III to which the spring I I3 is connected (Fig. 2) is positioned so that, after said clutch has rotated about three-quarters of a revolution, the stud engages the underside of the pawl I09 and raises it to free the lug III on latch III. This latch is then moved counterclockwise by its spring III to place its lower hooked end in position to engage the clutch control member I I2 as it comes around to its home position. As the arm IIZ engages the latch III further movement of the clutch causes the dog II to be rotated to disengage the clutch. Thus the clutch is automatically disengaged after it has rotated one revolution.

Means is provided for insuring that a complete cycle will occur even though the key TR is released immediately after being depressed. Re ferring to Fig. 2, when the transfer key TR is depressed, the slide 95 moves forward. The slide is thereupon temporarily latched in position by a pivoted latch I05 urged clockwise (Fig. 2) by spring I05, said latch having 2. lug on it positioned to engage a notch in the slide shown in Fig. 2. The latch holds the slide in its forward position until said latch is released.

Normally the latch I05 is momentarily rocked counterclockwise during the latter portion of the cycle of the drive shaft 29. The shaft 29 carries a clearing cam 85 operating against a stud I35 on an arm 85 pivoted at 85. The arm 85 is con nected to the clearing link 85 and is urged clockwise by a spring 85 (Fig. 2). The parts are timed so that the clearing cam acts near the latter part of the cycle of operation to move the link 95 forward and then return it rearward as described in more detail in said British patent. The clearing link 85 carries a pass-by pawl 85 urged clockwise in Fig. 2 by a spring. The latch I05 carries a stud I05 that is in the path of the nose of the pawl 85 and against which the pawl normally limits. As the clearing link 85 is moved forwardly the pawl 85 passes the stud Hi5 but, upon the rearward movement of said link, the pawl engages said stud and momentarily rocks the latch I05 counterclockwise to release the slide 95. The slide is then free to return to normal under the urge of its spring 98, which movement releases the key TR.

Provision is also made for preventing the latch I05 from moving back to latching position in the event the key TR is held depressed beyond the time required for the cycle of the'parts. For this purpose a second latch I80 is provided pivoted to one of the machine frames and urged clockwise in Fig. 2 by a spring I8I. When the slide 95 is in its normal rearward position the stud I92 on said slide to which the spring 88 is connected holds the latch I00 in the ineffective position of Fig. 2 against the tension of the spring I8I. However, when the slide 95 is moved forward by depression of the transfer key TR, the stud I82 moves away from latch I80, whereupon the latch moves to a position such that, when the latch I05 is momentarily rocked counterclockwise during the latter part of the cycle to release slide 95, said latch I05 will be caught and held by the latch I80. This condition obtains until the slide 95 moves rearwardly, whereupon said stud I82 will engage the latch I80 and move it to the Fig.

2 position, thereby releasing the latch I05. Additional means is provided to accomplish the same result, making it possible to omit the latch I if desired. The lower end of latch I05 carries a. stud I05 positioned to move into an inclined slot in the left-hand end of the arm I09, said lefthand end of the arm also carrying a spring held pawl I09 having its outer end turned up slightly. At the time the latch I05 is momentarily rocked counterclockwise to release slide 95, am I09 is in a clockwise position from the position shown in Fig. 2 so that the stud I05 can move into the slot in the end of said arm I09. The slot is shaped so that the movement of the latch I05 raises said arm slightly after which the spring urge on arm I09 and the incline of the slot tends to hold the latch I05 in its released position. This condition obtains until the transfer key TR is released, whereupon the slide moves rearwardly, the arm I01 rocks clockwise. and the arm I09 is moved to the rear to release the latch I05.

A safeguard is provided to prevent the clutch member III from overrunning the disk Ill which rotates counterclockwise as viewed in Fig. 2. In normal operations, one of the teeth of the disk Ill, which is the driving member, engages the underside of the dog I I5 to carry the member III and the clutch assembly with it. If, however, the member I I4 should start running ahead of the disk III it can move only a limited distance relative to said disk before the edge of the semi-circular slot I I5 engages the underside of the next tooth of the disk and prevents any further overrunning.

Provision is made for clearing the rear register and, since it is usually desirable to also clear the front register at the same time, the mechanism that clears the rear register also acts to clear the front register. The motor is caused to operate this mechanism by depression of the clearing key C (Fig. 2) which starts the motor and causes clearing cams to operate as de-- scribed in detail in said British patents.

Viewing the rear register and associated parts more generally, it will be apparent that a differential mechanism has been provided for operating said register which mechanism is separate and distinct from the differential mechanism governed by the amount keys for entering items in the front register. This second differential mechanism is governed as to its differential positions by stepped members that continuously reflect the amount in the front register. Said differential mechanism is caused to operate at the option of the operator by the depression of the key TR which starts the motor and conditions special driving connections operated thereby so that the special differential mechanism is operated to cause an amount to be entered in the rear register which amount has been indexed by the front register. This cycle of operation of the mechanism by the motor is a separate and distinct operation from the motor driving operatlons that occur when the amount keys are depressed.

Subtraction As previously mentioned, subtraction may be performed without requiring that the operator select keys on the keyboard representing the complement of the subtrahend. Instead, he simply enters the subtrahend on the amount keys in the same manner as an add item is entered and then moves a subtract key, whereupon the machine automatically operates to subtract the item from the rear register,

The manual operations are substantially the same as in performing subtraction on a key-set motor-driven calculating machine in. that an item to be subtracted is entered on the amount keys after which a subtract motor bar or key is manipulated to cause the machine to perform a subtraction cycle of operation.

The item entered additively in the front register is subtracted from the rear register by adding the complement of said item into the rear register. By the term complement of said item is meant the value 10 -1: wherein n is the number of orders in theregister into which the entry is made and a: is the value of the said item. For this purpose, each sector 14 is provided with a second set of stepped shoulders 15 (Fig. 1) which is used in performing subtraction. This second set of shoulders 16 is not normally active but provision is made for moving the sectors 14 to render the shoulders 16 active in subtraction. When the shoulders 16 are active, they are adapted to limit the movements of the links 18 in accordance with the complement of the amount standing in the front register. In order that the correct complemental value io -a: may be entered in the rear register, the shoulders 10 on the units order sector 14 (Fig. 5) are complemental to the shoulders 15 on said sector 14 with reference to the base whereas the shoulders 16 on the sectors 14 (Fig. 4) for all other orders are complemental to the shoulders 15 on said sectors with reference to the base 9." Thus, if the amount 72 entered in the front register is to be subtracted from the rear register, and the sectors 14 are swung to position to render the shoulders 16 active, and the links 18 are moved until stopped by the shoulders 10, the

units order link will move 10-2 steps or 8 steps,

the tens order link 18 will move 9-7 steps or 2 steps, and all higher order links 10 will move 9 steps.

The subtract key I20 is'carried by a lever III pivoted at I2I. The key top is positioned at an angle so that the operator can very easily place his finger on it and push it rearward. The rearward movement of the subtract key causes a special cycle of certain parts of the machine in much the same manner as when the transfer key TB. is depressed.

The subtract lever H9 has a rear extension I22 provided with a cam slot I23 in which is positioned a stud I24 on the bell crank 81 pivoted at 88 and connected to the transfer key TR at I00. The shape of the cam slot I23 is such that, when the subtract lever is rocked clockwise from the position of Fig. 2 to that of Fig. 3, the bell crank 81 is rocked clockwise. This pulls the link 00 forward and releases the bell crank 84 (Fig. 2) so as to place them under the control of the cam 83. The clockwise movement of hell crank 81 also moves the control slide 3! forward where it is temporarily latched by the latch III. This starts the motor and engages the clutch for rotating the cam 83 through a single revolution during which the bail 8| is moved rearward to permit the differential links 18 to move rearward to differential positions determined by the index members 14.

For changing the position of the index members 14, the subtract lever H8 is. provided at its lower end with a cam slot I28 in which is positioned a bail I3I carried by arms I32pivoted at I32 to stationary frame plates. The arms I22 projections II1 on the links 68 pivoted at 31. As.

previously described, the links 68 are connected to the levers 64 carrying the studs 62 cooperating with the snail cams 6| on the register pinions 41. Each of the links 68 also has a slot 69 in which is positioned a stud 10 on an arm of the bail 12 of which the corresponding index member .14 is a part. The cam I29 in the lower end of the subtract lever H3 is shaped so that, when subtract lever is rocked clockwise from the position of Fig. 2 to that of Fig. 3, links 88 will be rocked clockwise about the pivot 61. As this occurs the upper ends of the links 68 will be rocked rearward from the position of Fig. 1 to that of Fig. 3. It will be observed that the upper ends of links 68 are much closer to the pivots 13 of members 14 in Fig.3 than in Fig. 1. The parts are proportioned so that the links 68 slide on the studs 10 at the time the links are rocking, the total result being to swing index members 14 clockwise about their pivots 13 when the subtract key is moved to subtract position. Thus, all the index members 14 which have been differentially positioned in accordance with the amount in the front register, will be swung to new positions corresponding to the "9s complement of the amount in said register. At the same time, the motor will be started, the clutch engaged, and the differential links 18 moved rearward to cause the actuators 53 to be moved to add this complement into the rear register. It will be understood that, in higher orders of the front register where the pinions are in zero positions, the corresponding links 18 will be conditioned to move nine steps. Thus, the

amount in the front register will be subtracted.

from the rear register by a process of complemental addition.

Near the end of the subtract cycle, the clutch releases the control slide as heretofore explained, whereupon said slide moves forward and, acting on the stud I00, rocks the bell crank 81 counterclockwise to restore the subtract lever II 8 and the key I20 to normal.

To provide against-rearward movement of the links 18 before the index members 14 have been moved to their new positions by the subtract lever, an interlock has been provided to synchronize these parts. Pivoted to the shaft I2I is a latch I35 (Fig. 3) connected by a weak spring I36 to a projection of th subtract lever I I8. The tail of this latch normally rests on a square stud I38 (Fig. 2) on an upward extension of one of the arms I32 that carry the bail I3I. The latch I35 also has a shoulder I31 for engagement with the side of stud I38 (Fig. 2). lever H8 is rocked clockwise with reasonable rapidity from the position of Fig. 2, the latch I35 will follow it in time to just move its shoulder I31 out of the path of stud I38 so that, th movement of the subtract lever can be oompletedwithout interference, the arms I32 being rocked clockwise by the movement of said subtract lever. If, however, the subtract lever is moved very suddenly, the weak spring I36 will yield and the shoulder I31 will catch stud I38 which thereby blocks the subtract lever against complete operation. To complete the movement, pressure on the subtract lever must be released and the lever again moved rearward. This interlockprevents the subtract lever being moved so rapidly'as to cause the index If the subtract bars I8 to be moved rearward before the index members 14 are properly positioned.

The shape of the slot I23 is such that, when the transfer key TR is depressed with the subtract lever in the position of Fig. 2, the stud I24 on bell crank 81 moves into the left-hand horizontal portion of the slot I23 where it looks the subtract lever against operation. Thus, an interlock is provided to prevent the subtract lever from being moved to subtract position while the transfer key TR is depressed.

From the above it will be'clear that an operator can either add or subtract items in the rear register at will. If he desires to add an item, he enters it on the amount keys and depresses the transfer key TR which immediately adds the item into the rear register. If he desires to subtract the item, he enters it in the same way but pushes the subtract key I rearward, whereupon the item is immediately subtracted in the rear regis-- ter. In these operations, the front register performs the function of an intermediate or temporary storage register where the item is stored until either the transfer key TR or the subtract lever II9I20 is moved. In both cases the differential index members of the differential mechanism for the rear register is positioned as for ordinary addition but when the subtract lever is moved this indexing is converted or changed to a complemental indexing. But, insofar as the,

operator is concerned, he is not interested in the mechanical details of the machine. The thing of interest to him is that it is merely necessary to enter the items and depress the proper key to get either addition or subtraction.

the transfer key TR being an add motor bar and the subtract lever Ila-I20 being the subtract motor bar.

It will be appreciated that the operations required for adding and subtracting in the register are no greater than those ordinarily employed on a key-set machine where a motor bar or a subtract key must be depressed after the item has been entered on the amount keys. In fact, the present machin provides for more efficient action in that the items may be added or subtracted in groups. For example, if there is a series of items to be added, the operator can enter them one after another on the amount keys without depressing any additional key or motor bar and then, after the group has been entered, he can depress the transfer key TR whereupon the sum of the entire group will be transferred to the rear register. Likewise, if he has a series of'items to be subtracted, he can enter each subtract item one after the other by simply depressing the amount keys without depressing a motor bar for each operation. After the series has been entered, he moves the subtract lever, whereupon the entire group will be subtracted from the rear register. Thus, the machine enables items to be added or subtracted in groups as distinguished from machines where it is necessary to add and subtract each individual item.

Decimal cut-out In some uses of the machine, it is not desired to transfer the amounts in the lower orders of the calculator, as, for example, where these orders represent fractions having values below what may be desired in the final result in the rear These keys are, in effect, an add and a subtract motor bar,

ones involved and when it is not desired to transfer in these orders, a decimal cut-out or wise against the tension of its spring I5I.

"full-cent" key is provided which blocks the transfer in the three lower orders. Such a mechanism is disclosed in Henderson 2,063,740 and said mechanism is used in the present machine.

Referring to Fig. 2, the machine has a decimal cut-out or full-cent key I40 which, when depressed, prevents the differential links TB in the three lowest orders from moving out of their normal or 0 positions so that no amounts are entered in these orders in the rear register. The key I40 is carried :by a stem I4I (Fig. 6) slidably and rockably mounted on a stud I 42 about which it is urged upward and clockwise in Fig. 6 by a spring I43. Near the upper end of the stem MI is a slot I 4| which, when the key is depressed, moves over the edge of one of the keyboard plates under the urge of spring I43 so that the key will be latched in depressed position. Pivoted to a lateral extension of the key stem I4I at I44 is a bell crank arm I44 urged clockwise about its pivot by a spring I46, the clockwise movement of the arm being limited by a stud I40 on the key stem I4I which stud engages a foot I41 of the arm I44. The arm I44 thus moves downward with the key stem but can yield upward against the tension of a spring I46. The arm I44 has a rearward extension I49 positioned over a stud I50 on a bell crank I5I pivoted at I52 and urged clockwise in Fig. 2 by a spring I5I. The lower arm of the bell crank I5I carries a relatively long stud I53 which extends for the width of the first three orders or banks of the machine. Also pivoted on the shaft I 52 in each of the three lower orders is a bell crank I54, each bell crank I54 having its lower arm astride the stud I53. The other arm of each bell crank extends for ward and the end of this arm has an abutment face for cooperation with a stud I51 on the dif ferential link I8 for its order. The bell cranks I54 are normallyabove the studs I51 so that .the links 18 are free to move but, when the key I40 is depressed, the arm'I44 engages the stud I50 and rocks'the bell crank I5I counterclock- As the bell crank I5I is rocked counterclockwise, its stud I53, acting on all three of the bell cranks I54, rocks them to the position of Fig. 6 where the abutment ends of the horizontal arms of said bell cranks I54 are in front of the studs I51 on the links I! in the three lower orders. It follows that, when the machine is operated to release the links 10 in all orders, those in the first three orders will not move rearward under the urge of their springs, but will be held in their 0 or forward positions and, consequently, nothing will be transferred to the rear register in the three lower orders.

The cut-out remains in effect until the key I40 is released which can be done by pulling it forward so as to disengage the notch I4I from the keyboard plate, whereupon the spring I43 will return the key upward, thereby releasing the bell crank I5I which is rocked clockwise by its spring I5I to return the bell cranks I54 to normal.

When the decimal cut-out is used in connection with subtract operations, it is necessary to make some provision to insure that the subtraction result will .be correct. It will be recalled that the shoulders I5 of the stepped index member 14 in the units order are complemental to the shoulders 15 with reference to the base 10" whereas in all other orders the shoulders I6 are complemental to the shoulders I5 with reference to the base-9 to insure the correct result in subtraction. But, when the decimal cut-out is used, this units order index member 14 is not effective. A correction should then be made in the fourth order of the machine. Provision has been made for effecting this as follows:

Referringto Fig. '1, the differential link 18 in the fourth column, instead of having an integral lug 11 on it, is provided with a slide I60 on its front end having a lug 11 on it for cooperation with the shoulders 16 in the member 14 in the fourth order. This slide I60 is mounted on two studs I6I carried by the link 18, the slide being urged forward by a spring I66 coiled about the forward stud I6I, said spring having a free end engaging a lug I68 on the slide. Normally the slide is prevented from moving rearward by a latch I62 pivoted on the forward stud I6I and having a shoulder I63 engaging the stud I64 on the slide. The latch is urged to a normal latching position by the other free end of the spring I66 which engages a lug I61 on the latch.

When the above-described parts are in the normal position of Fig. 'l, the link 18, together with its slide I60 and the lug 11, is in condition to act in a normal manner and in the same manner as the other links 10. However, if the slide I60 is released by releasing the latch I62, the link 18 in the fourth order is permitted to move an extra step determined by the length of the slots in slide I60 in which the studs I6I are positioned. This extra step of movement is wanted only in decimal cut-out operations and only when these are subtract operations. Provision is, therefore, made to control the latch I62 by both the decimal cut-out key and the subtract lever.

Pivoted on the shaft I52 is a bell crank I69 (Fig. '1) having its lower arm astride the stud I53 on the bell crank 'I5I. Another arm of bell crank I69 is positioned above the lug I61 on the latch'l62 (Fig. '1). When the decimal cut-out key is depressed, as in Fig. 6, the bell crank II is rocked from its A to its B. position. The movement of the stud I 53 rocks the bell crank I69 but not sufliciently to release the latch I62,

the parts being moved to the full-line position of Fig. '7. But, if the subtract lever is also moved to subtract position, the latch will be released by the following mechanism.

Pivoted on the stud I42 (Fig. 6) is a lever "2 having a nose I1I on its upper end and a slot I13 in its lower end positioned astride the bail Ill. When the subtract lever is moved to subtract position, the bail I3I is moved from the full-line to the dot-dash position of Fig. 6 through connections heretofore described. As this occurs, the lever I12 is rocked clockwise and its nose engages the stud I50 on the bell crank I5I to rock said bell crank to move the bail or stud I53 from the B to the -C" position of Figs. 6 and '7. This rocks the bell crank I60 counterclockwise far enough to cause it to release the latch I62 and, since both the decimal cut-out key and the subtract lever are held in depressed position for the machine operation, it follows that, during the ensuing operation. the differential link 18 in the fourth order can move an extra step so that the subtraction result in the rear register will be correct.

When the link 18 is returned to normal at the end of the cycle, an upward projection I (Fig. .7) on the slide I60 engages thestud I52 and arrests said slide while the link 10 continues to move forward. Also, near the end of said cycle,

released and returned to normal. This releases the lever I 12 (Fig. 6) which is returned to its normal position, and the return of this lever releases the bell crank I5I, which is returned to normal by its springs thereby releasing the latch I62.

An interlock is provided to prevent depression of the decimal cut-out key I40 while the sub-' tract key is depressed. Referring to Fig. 6, when the subtract key is depressed, the bail I3I moves from the full-line to the dot-dash position, which rocks the lever I12 clockwise. But if the decimal cut-out key I40 has not been depressed, the stud I50 will not have been engaged by the arm I49 and will not have been moved downward far enough so that it is in'the path of the nose I1I of the lever I12. Consequently, lever I12 will not engage said stud but, instead, will move in front of it. If, then, an attempt is made to depress the key I40, the latter cannot move downward to effective position because the stud I50 is blocked by the end of lever I10 and the arm I44-I 49 cannot move the bell crank I5I counterclockwise. It would be possible under such conditions to depress the key I40 to stretch the spring I46 but this would not result in conditioning the parts for subtraction. The arrangement is such that the operator is forced to depress the decimal cut-out key first and the subtract key second when he desires to get a subtraction operation with decimal cut-out.

From the above it will be clear that a machine has been provided in which subtraction can be easily performed, either for thefull capacity or for the partial capacity of the machine.

I claim:

1. An amount-key-responsive calculator of the class disclosed having a keyboard provided with a plurality of depressible amount keys, a plural order amount differential mechanism, a normally inactive motor driving means for said differential mechanism, an item-receiving registering mechanism at the front of said keyboard, means responsive to the depression of each amount key for starting said motor driving means and causing it to operate the differential mechanism in the order of said key to immediately enter the corresponding digit additively in said item-receiving registering mechanism and to then stop, a-balance registering mechanism at the rear of said keyboard, mechanical subtraction means extending from front to rear of said machine. operable to subtract the amount in said itemreceiving from said "balance registering mechanism, driving connections for said subtraction means operable by said motor driving means, and manipulative means for starting said motor driving means and for conditioning said subtraction means and its driving connections to cause said subtraction means to be operated by said motor driving means through a special cycle independently of said amount differential mechanism, whereby, after an item has been entered on said amount keys. it will be subtracted from said balance" registering mechanism immediately upon a manipulation of said manipulative means.

2. An amount-key-responsive calculator of the class disclosed having a plurality of depressible amount keys, a plural order amount differential mechanism, motor driving means for said diifer-' ential mechanism, an item-receiving registering mechanism, means'responsive to the depression of each amount key for causing said motor driving means to operate the differential mechanism in the order of said key to immediately enter the corresponding digit additively in said item-receiving registering mechanism, a "balance" registering mechanism, addition-subtraction means operable to selectively add either the amount in said item-receiving registering mechanism or the complement of said amount to said "balance registering mechanism, driving connections for said addition-subtraction means operable by said motor driving means, and selectively operable manipulative means for conditioning said addition-subtraction means and its driving connections to cause them to be operated by said motor driving means through a special cycle independently of said amount diiierential mechanism, whereby, after an item has been entered on said amount keys, it will be added to or subtracted from said balance" registering mechanism immediately upon operation or said manipulative means and in accordance with the selective operation of said manipulative means.

3. An amount-key-responsive calculator oi the class disclosed having a plurality of depressible amount keys, a plural order amount difl'erential mechanism, motor driving means for said differential mechanism, an item-receiving registering mechanism, means responsive to the depression of each amount key for causing said motor driving means to operate the differential mechanism in the order of said key to immediately enter the corresponding digit additively in said item-receiving registering mechanism, a "balance registering mechanism, a special differential mechanism between said item-receiving and said balance" registering mechanisms having,

portions selectively conditionable to transmit either the amount in said item-receiving registering mechanism or the complement of said amount to said balance registering mechanism, driving connections for said special differential mechanism operable by said motor driving means, and selectively operable manipulative means for conditioning said special difierential mechanism for transmission of said amount or of said complement and for causing said motor driving connections to operate said special difierential mechanism through a cycle independently of said amount diflerential mechanism, whereby, after an item has been entered on said amount keys, it will be added to or subtracted from said balance" registering mechanism immediately upon manipulation of said manipulative means and in accordance with the selective operation of said manipulative means.

4. An amount-key-responsive calculator of the class disclosed having a plurality of depressible amount keys, a plural order amount difierential mechanism, motor driving means for said differential mechanism, an item-receivin registering mechanism, means rseponsive to the depression of each amount key for causing said motor driving means to operate the differential mechanism in the order of said key to immediately enter the corresponding digit additively in said item-receiving registering mechanism, a balance regstering mechanism, a plurality of differential stop elements continuously responsive to the amount in said item-receiving registering mechanism, said stop elements being movable from a position where one set of stops is eifective to another position where a complemental set of stops is efiective, a set of differential members operatively connected with said balance registering mechanism and movable into engagement with the ei- Iective set of stops 0! said stop elements, driving connections for said differential members operable by said motor driving means, and selectively operable manipulative means for positioning said stop elements and conditioning said drivin connections to cause said diiierential members to be operated by said motor driving means through a special cycle independently of said amount differential mechanism, whereby, after an item has been entered on said amount keys, it will be added to or subtracted from said balance registering mechanism immediately upon manipulation of said manipulative means and in accordance with the selective operation of said manipulative means.

WALTER J. PASINSKI.

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