US371496A - Adding machine - Google Patents

Description

(No Model-1) 4'sheem-snee1 1. n

D. E. FELT.

ADDING MACHINE.

110.371,49@ Patented 001. 11, 1887.

;-Ftglizs Ill 11"" lil lHl IUI lllhlhiu "l (No Model.) 4 Sheets-Sheet 2.

D. E. FELT.

ADDING MACHINE. 10.371 496. Patent d 1887.

(No Model- 4 Sheets-Sheet 3. D. E'. FELT.

ADDING MACHINE.

No. 371,496. Patented 004:. 1l,` 1887.

(Nd Model.) 4 Sheets-Sheet 4. D. E. FELT.

.ADDING MACH-INE.

No. 371,496. Patented Oct. 11,1887.

UNITED STATES PATENT OEEICEO DORE E. FELT, OFCHIOAGO, ILLINOIS, ASSIGNORTO IIIMSELE AND OHAUN- OEY W. FOSTER, OF SAME PLACE.

ADDING-MACHINE.

SPECIFICATION forming part cf Letters Patent NoA 371,496, dated October l1, 1887. l

(No model.)

To aZZ whoml it may concern,.-

Be it known that I, DORE E. FELT, a citizen of the United States, residing in Chicago, in the county of Oook and State of Illinois,

have invented a new and useful Improvement in Adding-Machines, of which the following` is a specitication..

This invention is au improvement upon the machine set forth in my patent Iiled July 6,

ro 1886, and numbered as Serial No. 366,915,

dated July 19, 1887.

To properly define the position of this invention in the art, I desire to say that machines of this order may be conveniently divided into two classesviz., counting-machines and calculatingmachines. I call counting-machines those wherein a series ofnumeral wheels are actuated by impulses or strokes delivered to the tirst or units wheel and periodi- 2o cally transmitted to the succeeding` wheels of the series by carrying mechanism, so that at the completion otI the tenth step of one wheel the wheel of the next higher order will be caused to advance one step.. Each wheel being numbered from 1 to 10, Athe quantities indicated proceed in decimal order. Machines of this class are common and are well understood. It is evidently desirable that overrotation shall be prevented, and therefore the 3o numcral-`whcels have been provided with stopmotion devices, sometimes simple friction devices, sometimes a positive stop, acting momeiitarily-tliat is to say, automatically released again inmediately-and sometimes a positive stop remaining in action until just before the completion of the revolution of the wheel next lower in order, so that the release takes place just in time for the nextvsucceeding impulse. Oalculatingmachines are those 4o wherein there is a series of numeral-wheels the same as in counting-machines and provided with similar carrying mechanism; but in addition each wheel has mechanism whereby it may be actuated and ata single motion caused to revolve independently through any part of its revolution.

Stopmotion devices to prevent overrotation are not more necessary in a calculatingmachine than in a counting-machine; but the 5o stop-motion devices suitable for the latter are insufficient and inapplicable to the former for these reasons: First, it is necessarythat each wheel shall be arrested and automatically locked during its period of rest, because the correctness ot' the calculation depends upon the presence of each wheel in its true position at the time when it receives its forward impulse, and, second, it must be adapted to be unlocked by the carrying device, and also by its own key-actuating device. The simple friction stop is inapplicable because it is not positive and is not reliable. The momentary stop, which is released immediately after ac tion, is inapplicable, because when the machine is being driven very rapidly it will frequently happen that the stop-motion device advances and is withdrawn again so quickly Ythat it fails to arrest the numeral-wheel,which then continues its movement and finally rests out of position. This, of course, t'alsities the result. The stop-motion device, which remains in action until the wheel of the next lower order is near to the completion of its revolution, is inapplicable, because it will pre vent any movement of the numeral-wheel by its own key. Therefore the automatic stopmotion device mu'st be independently released by its own key mechanism, as well as by the carrying part, which is actuated by the numeral-wheel next lower in' order. So far as I am aware, no calculating-machine has been provided with means for locking its numeralwheels during their periods of rest and for unlocking said locking means independently by the carrying device and by the wheels own key-actuating device.

The main feature of my present invention is the provision of a positive stop-motionldevice applied to the numeral-wheels and called into operation whenever a number is carried from one column to another, and said stop-motion device remains in engagement with the wheel acted upon until the wheel neXt lower in order has nearly completed its revolution, or until released by the key-actuating mechanism pertaining to the wheel arrested by said stopmotion device, thereby preventing such wheels from overrotation under the power thus received. This stop device and the stop device to prevent overrotation of the wheels when receiving power directly 'from the keys together effectually do away with the evil ot' over^ IOO movement by the wheels, while neither ofthem alone can prevent it entirely. As the carryi ng mechanism works quickly, the liability upon the part of the wheel actuated thereby to move beyond the proper point is very considerable.

Another At'eat-ure of importance is the imparting of motion to the key-stop levers an iustant bet'ore they actuate the stop-motion devices, or, in other words, the getting ot` said levers under way before they begin their work. In this manner they are caused to act quickly when they do act, so that the stopdetents move decisively and arrest the wheels instantly and positively.

There are other branches of the invention, some of which rela-te to the mechanism t'or setting the wheels preparatory to commencing an adding operation, all et' which will be fully understood by reference to the accompanying drawings and the subjoincd description, in thc former of whieh- Figure 1 isalongitudinal vertical section of my improved machine. Fig. 2 is a partial plan and partial horizontal section ol' the same. Figs. 3 and 4 are partial sections, showing the stop-motion devices employed with the carrying mechanism in two different positions. Fig. 5 is a partial section similar to Fig. l, some ofthe parts being broken away. Fig. 6 isafront elevation ot' two adjacent numeralwheels, showing the carrying part and its stop mechanism used with one ot' them. Fig. 7 is a side elevation of one ot said wheels, showing the cam andthe spring-lever used in carrying. Fig. Sis a detail side view ot' one of the disks and ratchcts accompanying each numeralwheel and the pawl for giving motion to the ratchet. Fig. 9 is a section on line 9 9 of Fig. 7. Fig. 10 is a section on line 10 10 ot' Fig. 5. Fig. 10 is a view oti the ratchet shown in Fig. 8, thc number ot' teeth being changed to adapt it to use with fractions. Fig. 1l shows the carrying stopmction with some ot' the parts in a slightly ditlerentposition f. om those shown in the other iigures. Figs. 12to18, inclusive, vare modifications ot' portions of the machine, Fig. 17 being` a` section on line 17 17 ot" Fig. 16. Fig. 1li is a detail horizontal section showing thcjunction of the lowest key ot' one of the series with the cross-bar G2 and stoplever G. Fiel 2O is a perspective view of the parts shown in Fig. 7.

In said drawings, in which similar letters ot' reference indicate like parts, A.. A represent the numcratwheels, whereof each stands for an order of numbers er fractions ol" numbers, and all are mounted upon the single shaft 13.

C C represent the operating-keys, there bcing a series for each order of numbers or frac tions and each key having the power noted upon it.

D l) are the vibrating springlevers operated bythe keys, there being one such for each series of keys. rlhese levers are made ot angle shaped metal, the horizontal portion d being perforated for the passage of the keys, and the vertical web d Lerving to stiiten the the pinions and disks are rotated by the downward movement ol' the levers, engage with and carry forward ratchets F, but do not return the latter during the contrary rotation caused by thc return-stroke of the levers. The ratchcts F are firmly joined to thc numeral-wheels and rotate'with them, and the extent of the rotation varies with the power ot' the key struck, the throw ot' the segmentlevers being in accordancewith such power. To obtain this variation thekeys are graduated in length, as described in my patent, No. 366,945, andthe levers are likewise stopped at the proper poi nt by suitable mechanism.

G G are the key-stop levers, there being one for cach series ol' keys, placed directly under the segment lever ot' the different series. They are struck and operated by those portions ot` the keys which project through the segmentlevers, asshown. Instead, however, ot' mounting these stop-levers upon laterally-located pivots at each end, I pivot them upon the cross-shaft G at the rear of the machine, and graduate the length of thc keys so that all will impart about the same amount ot' movement to them. For strength and rigidity, the stop; levers are made ol' U shaped or channel metal, as shown at Figs. 5, 10, 15, and 16.

The stoplevers are connected to the vibrat ing detents J by the rods J, which arejoined to the detents at their upper ends, and are formed into loops y', inclosing the stop-levers at their lower ends. (See Fig. 10.) \Vhen the stop-levers strike the bottom ol' these loops j, they carry the rods and detents with them and cause the detcnts to engage the cquispaced teeth or wires t', secured in the nuincral-whcels and their companion ratchets F, thereby absolutely stopping the rotation ot' the latter parts. The detents are lifted out ot' engagement with the wheels by the springs J, and the stop-levers are raised by the springs g. The crossbar G2 forms a stop to the upward movement of the stoplevers.

My present mode ot' actuating the stop-mo tion detent J diifcrs, however, in some respects from my formerapplication. Thus thclowest or first key of cach series is connected to and aetuates thc detent directly. The detents for this purpose are provided with latcrally-cxtending pinsj, which are engaged by the forwardlyextenditig-arms j upon the keys, (scc Fig-5,) whereby, when the keys are depressed, the dctents are called into action. These same keys may, however, be called upon to serve a IIO dfO

useful purpose in guiding the stop-levers, the forked ends of the latter (seen at Fig. 19) receiving the prolonged lower ends of said keys and sliding up and dwn the same.

Another feature in-which I vary from my former construction is this: The loops j are elongated vertically, so that the stop-levers G must move some distance before they begin to actuate the detents. I find this is important, because if the detents begin to move simultaneously with the levers the resultant action of the detents is not quick enough when the keys are struck rapidly, and the overrotation of the nnmerahwheels is not effectually pre` vented; but by getting the levers under way vbefore they act the detents are caused to move with the celerity needed to prevent the evil referred to. p

The extent of the stroke imparted to the segment-levers bythe various keys is regulated by theengagement of the detents with the numeralwheels, each key being calculated to bring the detent into action when the numeral-wheel has been rotated to the proper point. The set-screws l5 are also useful in adjusting the stroke of the segment-levers and determining theirupper position. The lowest keys of the several series pass through notches in the cross bar G2, Fig. 1.9; so they are held against lateral deliection at both top and bottom. This enables them to steady the segment-levers at their moving ends, and the stoplevers also.

Spring-actuated stops K engage with the teeth and prevent backward rotation of the numeral-wheel.

In my present machine I store up power whereby to actuate the carrying mechanism, as in my previous machine. rllhe indicatorwheels are provided with cams L, (see Fig. 7 and a pivoted cariyinglever, M, is located adjacent to each wheel, and forced toward the wheels by the spring m. (See Fig. l.) Each lever M has an arm, in', riding upon cam L, and also a push-pawl, m2, engaging with the teeth t of the wheel next higher in order, the lever M heilig bentlatcrally, as shown in Fig. 6, to bring the pawl mt in line with the ratchet ofthe wheel next higher in order. The pushing back of the lever M to the position indicated in dotted lines at Fig. 7 by the cam L stores np power in the spring in, which, when the arm of the lever has passed the highest part of the cam, is utilized in returning the lever to its starting position and in carrying the next higher wheel one point or number. Each of the wheels, except the lowest, may be thus actuated, and several of them may be simultaneously actuated by this carrying mechanism. It is not necessary that-the cams should exert any pushing force against the levers until the wheels have been rotated to indicate 4, or t-hereabout, and hence the cams are circular for a portion of their outline.

It will be evident that in a machine having a series of keys for each numeral-wheel the speed with which each wheel is moved will be much greater when a high numeral-key is struck than when a low one is struck. In Fig. 7 the numeral-wheel with its cam and the arm M are shown intheir initial position. When the wheel is rotated slowly, the spring m will promptly return the lever M as its arm passes off the point of the cam; but when the wheel is rotated very rapidly the momentum of the outward movement of the leverM is so great that the spring mis occupied for a moment of time in overcoming and reversing this motion, and during that moment the numeral-wheel will pass'so far vforward that the carrying part will fail to act. v'Ilo prevent this overmotion, the cam L is inserted to return the arm M positively when the motion is too rapid for the spring in. (See Fig. 20.)

The stop-motion mechanism for preventing overrotation of the carried wheels when actuated by their carrying devices will next be described. There is, ofcourse, a mechanism of this sort for each of the numeratwheels. Upon the shaft m3, whcreon the carryinglevers may also be journaled, are pivoted a series of detents, N, one for each numeralwheel, and springs n press such detents toward the wheels at all times. These detents are intended to engage with theteeth z', and are always in locking engagement therewith when at rest, except when the numeral-wheel next lower stands at 7, 8, or 9, or` when released momentarily by the keys. It will thus be seen. that this part of the stop-motion mechanism serves a very useful and additional function, and that by means of the detents N on the one side and the stops K on the other all the wheels are absolutely locked during the major part of the time. To release the wheels from this lock by the detents N, pins u' at the upper ends thereof are provided to ride upon the peripheries of the disks E2, and as such disks are notched, as at n?, the pins resting in the notches during the locking, it follows that the pins and the detents are t'orced outward whenever the disks are rotated by the segmentdevers. The detent N and its', spring and pin are employed with the lowest. numeral-wheel; but the rest ot' the stop motion mechanism is not necessary with that wheel, as it is never actuated by carrying mechanism.

Upon the detents N are pivoted bellcrank levers O, the downwardly-extending limb of which is acted upon by a spring, o, and the other limb whereof is provided with catch 0 at its extremity. The spring o presses said lower limb toward the front, and thus tends to lift the other limb.

rIlhe carrying-levers M are each provided with a laterally-projecting pin or stud, I), which extends through lthe wide opening p in the detents N, as indicated, in' position to act upon the detentitself and upon the lowerlimb of the bellcrauk lever O. The catch o engages at each carrying operation with a trans Verse bar, q, extending from side to side of the machine, and the other limb of the lever O extends past said piu P, upon the inside thereof.

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The bellerank O and bar q serve to detain the stop-detent N a sufficient time to permit the carrying-lever to move the nu 1neral-wheel and prevent said detent from engaging too soon. The stud I strikes the downward-projecting arm ofthe bell-crank O and releases the catch from said bar q in time to permit the detent to engage one of the pins t'.

The parts just described constitute, in combination with the detent-s N, the stopmot-ion ofthe carrying mechanism, and its operation is as follows: It' the keys otl any column-as, for instance, the units-column-be struck, the earryinglever M, actuated by the cam of the units-wheel, will commence to move backward from the wheel from the time said wheel indicates a until it has reached 9. In the backward movement of the cariyinglever, the stud I) comes in contact with the edge of the opening p in the detent N of the wheel next higher in order at the moment when the wheel which actnates said carryinglever indicates 7, so that said next higher numeral-wheel is, when the time arrives for it to be moved, released from the locking-action of its own detent N. During the latter part ofthe backward movement ofthe detent the upper limb of the bell-crank lever comes in contact with the bar q and is detlected thereby until, by the continued movement of the detent, the catch of said upper limb becomes caught by the sharp edge of said bar. This takes place when the keys have brought the unitswhcel to 9. The parts are now in the position illustrated at Fig. Il, with the pin P at the same side of the opening p oecupied during the backward movement, but the lower limb of the lever O stands toward the farther side oi' said opening. The continued rotation of the units-wheel from this point, whether due to a key-stroke already given or to a stroke to be given or to the action ofthe carrying part, will result in carrying the highest part of the cam L ofthatwheel beyond the arm of the carrying-lever, so that the lever is free to yield to its springm and to move toward the wheels and rotate the next higher wheel one number or point. The detent N is detained momentarily Yfrom keeping company with the lever in this return movement until the pin I? strikes the lever O and disengagcs the latter from the bar q, the detention being due to such engagement. The detent N then resumes its normal position quickly under the power of its spring, locking the carried wheel against further movement. The operations of the carryingiever M and the locking detent are relatively timed, it will be noticed, so that the former has somewhat the start of the latter, thereby insuring the carrying rotation before the locking takes place. A feature of value in this stop-motion contrivance is that it is at liberty to move into locking position before the rotation.of the carried wheel has been completed, it only being necessary that to engage the next tooth, while I prevent it from re-engaging the same tooth it hasjust released by detaining it momentarily, as specified. It will be understood that the operation of the stop-motion will be precisely the same in the case of any other pair of adjacent wheels as that described in the case of the u nits and the tens wheels.

The setting of the machine preparatory to commencing an operation is by my present invention an easy and quick operation. A rotatable bar, R, having a dat side, is placed transversely of the machine in the position indicated, and provided with a crank-arm, r, whereby it may be partially turned in its bearings. This arm 1" may be inside or outside the case of the machine, as preferred, though I prefer to actuate it by a key, S, somewhat similar to the numeratkeys, and to locate it inside, as shown at Figs. 3 and 4. The dat side of the bar R aets'npon the projeetion s upon the lower end ofthe detents N and forces said detents to release the numeralwheels, so that the latter are all free to be turned in the forward direction, and I actuate them in that direction through the main shaft B. The latter for this purpose is extended through the side ot the case and provided with a thumb-wheel, Z), whereby power may be ap` plied. Adjacent to the cam side of each numeral-wheel I insert in said shaft a pin, T, which, when the shaft is rotated, comes in Contact with the abrupt face of a depressible stop, U, projecting from the side face of each of the cams. As these pins are all in the same plane and the stops are located at the same point in all the wheels, it necessarily results that all the wheels may be rotated to indicate the same ligure by rotating the main shaft, the pins coming in contact with the stops at some point in the course of the revolution, such point depending upon the position occupied by the wheel when the setting is commenced. To avoid the engagement of thepins T andthe stops U when the wheels alone are rotated, as in adding, the stops are made sloping upon one side and inserted in recesses which allow them to sink out of the way when the pins pass over such sloping sides. The construction I prefer for these stops and their holding recesses is clearly shown at Fig. 9. Thestops are L-shaped, and when placed in position are securely held without being pivoted or otherwise attached to the cam or wheel. At one extremity the stop is provided with a nib, a, which passes under the cam L, and another nib, a', which enters the recess u2 in the web of the wheel. This end of the stop is eiliectually held by these nibs, while they do not prevent the necessary motion at the other end. At said other end is an enlargement, ai, which engages with the cam L and prevents the throwing out ofthe stop under the pressure of the spring u,by which it is returned to its normal position after it has been depressed by the pin T. A recess, n, allows the enlarged end ai to pass inward when the stop is depressed.

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The steps involved in the setting operation are, first, the drawing back of the detents N by the crank r and the bar It, and then the rotation of the main shaft B until all the wheels have been brought into line at the zero position. The pressure upon the crank a should be continued until the wheels have Y been rotated to indicate 7, or thereabout,wheu

changes inthe numerals upon the wheel; but

in principle the machine for adding fractions is unchanged from that used for whole numbers, and 1t will be understood that other fractions than the particular ones illustrated may be added in my machine if similar changes to those mentioned be made.

A feature of great importance in my machine is the provision for excess motion by the disks E". I have shown at Fig. 8 the relative position of the pawl carried by said disk and the ratchet F when at rest, and it will be noticed thatthepawl must move some distance before it engages with the ratchet and moves the latter. This preliminary or excess movement upon the part ot' the disk and pawl, while not necessary so far as actuating the ratchet is concerned, is essential t0 enable the disk to release the ratchet and number-wheel from the lock of' the detent N before movement is imparted to them, as will be readily understood.

At Figs. I2 and I3 a modification of the carrying stop-motion is illustrated. The springactuated de tent N, corresponding to the detent N, alreadydcseribed, is provided with a similar pin, a, intended to engage with the notched .periphery of disk El, and is detained for the same purpose as detent N is detained by a spring-catch, V, and released from said catch by providing the lever M with a lliange, m, which will act as a cam to force said catch away from the detent. The detent is drawn back by the carrying-lever M through the medium of a pin, P', upon the latter.

In Fig. 14 the detent N2 corresponds with detent N in that itlocks the numeral-wheel in a similar way, is provided with a similar pin, ai, engaging with the notched disk E, and is drawn back by a pin, I, upon the carryinglever passing through an elongated opening, p, in the detent. With this detent I have shown no detaining device, and I regard it, therefore, as a less vdesirable construction than the forms wherein the detent is held back to give the carrying-lever time to do a part at least of its work.

Figs. 15 to 1S illustrate a modification of.

the construction of the connection between the stop-levers G and the vibrating detents J. The rods J are here employed, but they are attached to the detents by looping their upper ends and passing such loop over guide-heads Z, the loops allowing the rods to move some distance with the stop leversbefore they actuate the detents, thus accomplishing the result dwelt upon above of getting the stoplevers under motion before they begin to actuate the detents. The attachment of the rods to the levers is also different from that previously shown and is a rigid one. It consists in bending the eids of the rods at right angles and passing the extremities thereof through openings in the vertical webs of the levers. Retaining loops or staples z are then passed around the rod and soldered to the upper surface of thelevers. By making the heads Z oblong, as shown, the loops of the rods may be slipped over them while held horizontally, and by then swinging them to the vertical position they become fastened or lnovably held. This same result would follow, of course, if

. the heads could be partially rotated upon their axes; but I prefer to rivet them to the detents, so they cannot be detached or moved.

The springs u and o may both be formed in one piece and are so indicated in the drawings.

I claim 1. In an addingmachinc, the combination, with the several numeral-wheels and their car rying mechanisms, of actuating-key mechanism for each of said wheels and positively-acting stop-motion detcnts for preventing overrotation under the impulses of said keys or carrying mechanism, substantially as specified.

2. In an adding-machine, the combination, with the numeral-wheels, their key-actuating devices,and their carrying mechanisms, of detents for preventing overrotation under actuations received directly from the keys, and other detents for preventing overrotation under actuations by the carrying mechanisms, substantially as specified.

3. In an adding-machine, the combination, with the series of numeral-wheels and their actuating devices, of the series of levers for actuating said wheels -in carrying, the series of springs in which power is stored for actuatiilg-` said levers, and the series of positively-acting stop-motion detcnts for preventing overrotation under the impulse of the carrying-levers, substantially as specified.

4. In an addingmaehine, the combination, with each numeral-wheel and its carrying-le ver, of a positively-acting stop-motion detent acting upon the wheel, and aspring for throwing said detent into engagement, substantially as set forth. f

5. In an adding-machine, the combination, with each numeral-wheel and its carrying-lever, of a positive stopmotion detent, a spring for throwing the detent into engagement, and

a catch or equivalent detaining devicefor de- IOO IIO

taining the detent momentarily, substantially as set forth.

6. In an adding-machine, the combination, with the numeral-wheels, of the spring-actuated positive detent N and the notched disk E2, having a movement independent of its wheel for releasing the wheel from the lock of said detent before said wheel is actuated, substantially as specified.

7. In an adding-machine, lthe combination, with the numeral-wheels, of the springactuated positive detent N, the carrying-lever, and the notched disk having` a movement independent of its wheel for releasing the wheel from the lock of the detent before said wheel is actuated, substantially as set forth.

8. In an adding-machine, the combination, with the carrying-lever and its actuating-cam, of the spring-actuated detent N, the pin upon the carrying-lever `for drawing the detent back, the bell-crank lever, and the barnnder which the latter catches, substantially as set forth.

tl. In an adding-machine, the combination of the stop-levers with the numeral-wheels, their actuating devices7 the lockingdetents J', and the connecting-rods J, the stop-levers having an excess of motion whereby they are enabled to get under way before actuating the detents, substantially as specified.

l0. In an adding-machine, the combination of the numeratwhcels, their actuating devices, the detents J', the connecting-rods J, and the stop-levers, the latter having an excess motion, as specified, and both detents and levers having separate lifting-springs, substantially as specified.

1l. The con'ibinatiou of the numeral-wheels, their actuating devices, dctents J', and the rod J with the stoplevers inelosed in elongated loops at the lower ends of the rods, substantially as specified.

12. The combination ofthe minieral-wheel, its actuating-segment, the series of keys, and the stop-motion detent J', the lowestkey being connected to the detent, so as to actuate the same directly, and the other keys acting thereon through the stop-lever and rod J, with the stop-lever and rod, substantially as specified.

13. In an addingsinachine, the combination Cf the nu1neral-wheels, their actuating-seg ments, and the stopvmotion detents J', with the lowest key of each series of keys, the latter being connected directly to and actuating said detents, substantially as specified.

14;. The stop-levers having the forked ends, in combination with the several series of keys actuating said levers, the lowest key of each series acting as a guide to one of the levers, substantially as specified.

l5. The combination of the stoplevers with the several series of keys actuating the saine,

the lowest keyof each series being let into the end of the levers, and the cross-bar G2,substan tially as set forth.

1G. The combination ofthe numeral-wheels in series, all borne upon a single shaft and provided with deprcssible stop-latches U, as speeiethwit-h said shaft,and the pins T, driven into said shaft for engaging said stops and rotating said wheel, substantially as set forth.

17. The rotatable main shaft and the numeralwheels mounted thereon, said shaft having' latches for engaging said wheels during its rotation, in combina-tion with the positive lockingdetents and the rotatable bar It, for releasing the detents to permit said wheels to bereturned to O by revolving said shaft, substantially as set forth.

1S. The numeral wheels provided with springlatches U, the shaft upon which the n u meral-whecls are loosely mounted,said shaft being provided with pins T to engage said l latches and rotate the wheels in one direction,

the locking-detcnts, and the bar It, for releas ing the wheels from said detents, in combination with the stops upon the wheels to engage with said pins and said detent, substantially as set forth.

19. The pinionsl'and the disks E2, notched upon the periphery, in. combination with the numeral-wheels A, the ratehets F, the pawl c, normally resting on said ratchet near the point a tooth, and detents N, substantially as set of forth.

20. The numeral wheels, the actuatingratchets, and the disks E, carrying the pawls acting upon said ratehets and also acting to release the positively-acting loeking-detents N, in combination with said detcnts, the disks having some excess mot-ion before moving the ratchets to give time for releasing the lock of the detents, substantially as set forth.

2l. In an adding-machine,the combination, with the numeratwh eels, of the carrying meehanisms and the positivelyactingstop-motion devices for preventing overrotation under the carrying impulses, the hook o', and bar q, whereby said stop-motion devices are caused to act an instant later than the carrying devices, substantially as set forth.

22. The combination, with the carrying-lever, of a positively-acting stop-motion detent for preventing ovcrrotation under the impulse of the carrying, said detent being auto matically withdrawn from engagement with the numeral-wheel by the lever as the latter moves back preparatory to a carrying operation, substantially as set forth.

DORR E. FELT.

Vitnesses:

H. M. MUNDAY, Law. C. CURTrs.

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