US1028161A - Adding and subtracting machine. - Google Patents

Description

J. G. VINCENT.

ADDING AND SUBTRAGTING MACHINE.

APPLICATION FILED APR. 6, 1908.

Patented June 4, 1912.

J. G. VINCENT. ADDING AND SUBTRAGTING MACHINE.

APPLICATION FILED APR. 6, 1908.

Patented June 4, 1912.

J. G. VINCENT.

ADDING AND SUBTRAGTING MACHINE. APPLICATION FILED APB.'6, 1908.

' Patented Julie 4, 1912.

6 3EEETSSHEET 3.

J. G. VINCENT.

- ADDING AND SUBTBAGTING MACHINE.

APPLICATION FILED APR. 6, 1908.

' Patented June 4, 1912.-

6 SHEETS-SHEET 4.

J. G. VINCENT. ADDING AND SUBTBAGTING MACHINE.

APPLICATION rum) APR. 6, 1908. I I I v Patented June 4, 1912.

. 3 W a M W1 M, V

J. G, VINCENT. ADDING AND SUBTRAGTING MACHINE.

APPLIOATIQH FILED APR; 6, 1908.

6 SHEETS-SHEET 6.

' UNITED STATES PATENT OFFICE.

JESSE G. VINCENT, OF DETROIT, MICHIGAN, ASSIGNOR TO BURROUGHS ADDING MACHINE COMPANY, 015 DETROIT, MICHIGAN, A CORPORA'IIQN OF MICHIGAN.

ADDING AND SUBTRACTING MACHINE.

Specification of Letters Patent.

Application filed April 6, 1908. Serial No. 425,466.

accumulate successive amounts, and also to print a list of such amounts and a total thereof whenever desired. It is common practice in the use-of such machines to per form subst-raction by adding to the'subtrahend the complement of the minuend or vice versa, to which end the keys which regularly carry inscriptions to guide the user 'in addition are frequently inscribed also' with complement-a1 numerals.

The principal object of the present inven-- tion is to adapt a machine of the above class for use in direct subtraction as by theturning of register wheels in a direction opposite that-in which such wheels turn when performin addition. Of course the mere reversal 0% direction in which such wheels rotate is no innovation of itself for it is commonly practised in machines of this class when taking totals or-sub-totals but in such case there are no transfer movements' of wheels in this reverse direction, whereas when the wheels are reversely rotated, for purposes of subtraction provision must be made for transfer; operations inasmuch as a wheel of lower order will frequently be required to borrow from the next adjacent wheel of higher forder. The

resent invention therefore has particularly in view the adaptation of transfer mechanism such as employed in machines of this class to the new use of efi'ectin the necessary borrowing when the maclgine is performing subtraction.-

According to the present invention a machine primarily organized for performing addition can be so adapted to the performance of subtraction that by. simply pressin a key or like manipulation the machine Wlll, when operated in the usual manner as by touching amount keys and pulling a handle, subtract instead of add.

The invention is here shown as applied to an adding and listing machine of the wellknown Burroughs type (See Burroughs Patents 504,963 and 505,078, September 12, 1893), in whichtype of machine transfer movements of register wheels are effected by excess movement of their actuating racks, such excess movement being effected through the medium of springs. By the present in vent-ion this same excess movement of racks is'utilized to effect the necessary borrowing in the performance of subtraction and the transfer mechanism is so modified to this end that provision is not only made for the backward rotation one step of a wheel of higher order by reason of the next lower wheel being rotated backward past the zero point, but also for continued borrowing across the entire set of wheels if need be, such continued borrowing taking place in the same operation of the machine as the initial borrowing. Thus, for example, if the wheels all stood at zero and the one-cent key was depressed and the handle of'the machine drawn forward and released, (the machine having of course been first properly prepared for performing substraction aiS by depressing a special key) the units wheel will be turned one step backward and all the transfer devices will be tripped though at the conclusion of this operation the numeral 9 shows only on the units wheel, the other wheels still exhibiting ciphers. However, theracks will have all (except of course the units rack) partaken of the "excess movement. So when the machine is again operated the higher wheelswill all be turned backward one step by the taking upof such excess movement of racks. Of course if another subtrahend was set up on the keyboard before the second pull of the handle further substraction would be done and perhaps further transfer tripping. Thus the .same operation of the machine completes the borrowing prepared for in the revious operation and also effects subtractlon and preparation for; further borrowing, so that the modification? of the transfer mechanism to serve for borrowing in subtraction, does not necessitate any more extended operation of the machine for subtraction than for addition, for, while in performing addition Patented June 4, 1912.

Furthermore, provision is made for automatically characterizing the imprint of a subtrahend to distinguish it from added items and totals and in this connection the known feature of specially characterizing totals and sub-totals is preserved, as also if desired the feature of specially characterizing numbers not to be added or subtracted. With the above and incidental objects in view the invention consists in certain novel features of construction and combinations of parts, the essential elements whereof are recited-in the appended claims and a preferred form of embodiment of which is fully illustrated in the accompanying drawings and described in detail hereinafter. Of said drawings Figure 1 represents in sectionalized left-side elevation a suflicient portion of a machine of the class indicated to. illustrate the application of the present invention thereto, all the parts being shown at normal, that is to say with the subtraction devices not called into play but the machine in condition for performing its usual functions of adding and listing of items and printing of totals; Fig. 2 is a similar View on a larger scale and not extending to parts at the rear of the machine, the subtraction devices being here represented as set so that the machine is ready to do subtracting; Fig. 3 represents a front elevation'of parts appearing in Fig. 2; Fig. 4 is a detail sectional elevation illustrating the relative positioning of parts when in a subtraction operation a transfer device has been tripped, also showing preparation for a continued or cross transfer; Fig. 5 is a somewhat similar View though not including illustration of so many parts, this latter figure illustrating the effect of initial movement of the handle in an operation of the machine next ensuing after the operation which would position the parts as indicated in Fig. 4; Fig. 6 is a section on the line 6'6 of Fig. 2; Fig. 7 is a view similar to Fig. 4, illustrating how continued borrowing is arrested when a wheel is reached from which borrowing can be done without such Wheel being required to borrow; Figs. 8 and 9 are similar detail elevations illustrating how the transfer projection on a register wheel acts similarly to trip a transfer device whether the wheel is rotated in one direction or the other; Fig. 10 is a sectional right-side elevation of the special printing devices, the same being illustrated as adjusted for the printing of a special sign to characterize an unadded and unsub tractedamount-y'Fig. 11 is a similar view but illustrates the changed relation of parts for the printing'of thespecial character denoting a subtrjahend; andf-Fig. 12 repre sents a sample' of printing done by the machine.

Many'of the parts shown in the drawings are practically the. same as those illustrated and described in the above-mentioned patents but it will be desirable to specifically mention them .and refer to their mode of operations inasmuch as this directly concerns the carrying out of the'present invention. Referring first to Figs. 1 and 2, on a central rock shaft 600 there are loosely mounted sideby side a series of levers 611 carrying segmental series of type-plates 618 at their rear ends and at their forward ends carrying studs 6 which occupy slots 6 in segmental racks 610, the latter connected with said studs by springs 6 which tend to move the racks=independently ofthe levers the length of said slots. Such independent or excess movement of the racks is provided 'for transfer or carrying purposes, the racks;

being normally held down against the stress of said springs. Thus plvoted transfer pawls 4:13 normally overlie studs 6 on said racks, the pawls bein yieldingly held in normal position bysprmgs 6 which connect them with pivoted latches 411 normally held by said springs against the, front ends of the forwardly-projecting arms of said pawls in the usual manner. Numbered wheels or dials 912 are arranged much as usual to display amount inscriptions at the front of the machine, said wheels carrying pinions 916 to engage the racks 610 respectively and each combined pinion a'nd'wheel carries a laterally-projetclng stud ,9, those of all the wheels except the one of highest order being adapted to displace the associated transfer pawl 413 as the wheels make complete rotations.

The racks are normally upheld by pivoted latches 4.15 of the usual form adapted to be severally displaced by depressionof amount keys 291 through the medium of detent strips 214 and adapted to be collectively displaced by depression of the total key 265 or the sub-total key 265 The lever's 611 are normally upheld on the forward side of the shaft 600 by the usual restoring frame or bail 613 which is secured to the rock shaft 600. and upon downward swinging of said frame without release of racks 610 the levers move the length of the slots 6 which is suflicient to bring the zero types to the printing line opposite the platen'l7. When amount keys have been depressed the levers move correspondingly to bring to the printing line types corresponding with the keys,

usual carried by a rocking frame 910, one

the latter setting stops as usual to limit the downward movement of the racks. [When a total or sub-total is to be printed the racks movedistances determined by the degree of rotation of wheels necessary to return them to zero and the types are setup to correspond.

The Wheels and pinions 912 and 916 are as side-plate of whichhas studs 958 and 958 adapted to be engaged by the upper'and lower branches respectively of a pitman 914 which is jointed at its rear end to a three armed lever 913. The latter as usual carries studs 960 and 960 adapted to be alternately acted upon by a wipe-plate or pawl 821 pivotally mounted on the upper end of an arm 813 which oscillates in every operation of the machine. The notched upper branch of the pitman is normally engaged with the upper stud 958 and at the outset of an operation ofthe machine the frame 910 will therefore be rocked to disengage the pinions from the racks. The pinions remain thus disengaged while the operating handle of the machine is drawn forward and the racks lowered. Then as the handle starts back the pinions are drawn into mesh with the racks to partake of the upward movements thereof. This is the ordinary adding opera .tion in a Burroughs machine and when a total is desired a blank stroke of the handle is first taken to restore any racks which have moved up for transfer purposes and then either the key 265 or the key 265 is depressed and the handle pulled. Depression of either of these keys lowers the pit-' man 914 disengaging its upper branch from the stud 958 and in case of depression of the key 265 permitting the lower branch of said pitman to engage the stud 958 so'that 'the pinions will be disengaged with the' wheels at zero. At the conclusion of such an operation the pinions are reengaged with the racks through the action of a roller 338 on the usual full stroke sector 311 against the cam-edge of a rearwardly-projecting arm 919 of the rocking frame 910. When the sub-total key is depressed the pitman is prevented from* engaging the stud 958 so that the pinionswill remain in engagement with the racks throughout the operation.

All of the above-described operations are wellknown as those commonly occurring in a Burroughs adding and listing machine and no detailed discussion of them is neces- 'saiiy. j I

t will be seen that to provide for direct to the key A causes the pitman to camrpast said stud and take-u the position at Once. which in the case of epression of the total key is not assumed until the handle starts on its backward or return stroke. The stem A of the key A slides through the-keyboard plates and is normally upheld by a spring a and at its lower end this stem is widened into a foot a which engages a roller a on the pitman 914. When the key is depressed said foot acting upon said roller forces the pitman down, disengaging its notched upper branch from the stud 958 and engaging its lower branch with the stud 958 as shown in Fig. 2. It will therefore be seen that in an operation of the machine with this key depressed the pinions will remain engaged with the racks during the forward stroke of the operating handle and be disengaged therefrom during the return of said handle, the timing in this regard being the same as when the total key 265- is depressed.

As reverse rotation of the Wheels 912for subtraction purposes is to effect transfer tripping when borrowing becomes necessary the pawls 418 are'modified to provide for their displacement by the projections 9 under rotation of wheels in either direction instead of only in a forward or adding direction as is ordinarily the case, such pawls heretofore constituting zero stops limiting backward rotation of the wheels. In the present instance as shown more clearly in Figs. 8 and 9 each of the pawls 413 carries at its lower end a pivoted camnose B 'recessed in rear of the pivot to receive a laterally-turned lip b of the pawl, said nose having a double taper on the forward side of the pivot. The nose B is permitted to rock on its pivot a limited extent which provides for an easy camming action of the projection 9 against either. the upper or the lower edge of the nose and displacement of the pawl under rotation of the wheel in either direction by reason of said projection wiping over the cam edge when one shoulder or the other of the recess of the nose comes to bear against the lip b.

The effect of displacing a. transfer pawl in backward rotation of a wheel will of course be to relieve the rack of next higher order from restraint normally imposed upon it by such pawl but as the lever 611 associated with such rack will at such time have necessarily lowered, the rackcannot rise and of course it is not intended that independent upward movement of the rack under such circumstances shall turn the next higher wheel because that wheel must be turned backward, not forward. The rack one step. Of course in such subsequent operation the wheel will turn farther back-.

ward if a key in its associated bank of amount keys has been depressed.-

The detaining of a displaced transfer pawl is effected by the engagement therewith of the associated latch lll'which also serves to detain the pawl when displaced in an adding operation. It is of course essential in either case that the pawl be held displaced until the rack has had an opportunity to partake of'its excess upward move ment which cannot ensue until near the very close of the operation of the machine." The return to normal of any displaced transfer pawls requires the retraction of the latches 411. In the regular Burroughs machine this occurs just about as the operating handle reaches the forward end of its stroke which is early enough in the case of addition because there is no rotation ofwheels until the handle starts back. However, in the case of subtraction the rotation of wheels accompanies the forward stroke of the operating handle. Consequently it becomes necessary to restore the transfer'pawls at the outset of such stroke so that the pawls may be ready to be again tripped. A rocking bail is employed for retracting the latches as in theregular construction but it is quite differently controlled. The numeral 902 designates the cross-rod of this bail, which rod is arranged to act against rearwardly-pro jectmg arms 411 of the latches; the reference numeral 902 designates oneof the two side-pieces of the bail and the reference nu-4 meral 904 designates a rock shaft to-Which these side-pieces are secured. The left-hand side-piece is formed with a rearwardly and downwardly-extending branch 902 (Fig. 2)

having a laterally-projecting stud 960 at its rear end. On the arm 813 there is pivoted intermediate its ends a bar 0. (Fig. 6) the upper branch of which carries a' wipe-pawl or plate 821 similar in form to the plate 821 'and similarly held central by a spring 0.

The lower branch of the bar 0 is"drawn by a light spring 0 into contactwith the'hub of the arm 813. The latch-restoring bail is normally drawn rearward by a heavier spring 0 applied to a downwardly-extend-- mg branch 902 of the side-piece 902 Normally the wipe-plate 821 has its central transfer pawls.

prong bearing against the stud 960 as. illustrated in Fig. 2, this wipe-pawl and the up per branch of the bar ,0 constituting in effect a. toggle joint normally broken. As the arm 813 swings rearward the forward shoulder of the said wipe-pawl strikes the said stud 960 and fulrums upon the same as the arm 813 continues toswing rearward straightening-the toggle joint with the of feet of lifting the bail-arm 902 and rocking the'bail forward, thus restoring the latches.

This occurs in the first part of the forward stroke of the operating handle and as soon as the arm 813 has traveled rearward far enough totake the toggle joint over the'center it quickly breaks under the stress of the spring 0 the spring 0 yielding, and the bail may thus quickly recover leaving the latches free to again spring over any displaced All of this occurs in that portion of the handle stroke which swings the restoring frame or bail 613 downward only far enough to permit the levers 611 following the length of the slots 6, and consequently before any movement of the racks-takes place except such movements as efi'ect borrowing resultant from transfer tripping in the previous operation. Hence,

in further movement of wheels. resultant from depression of amount'keys retripping of transfers may take place.

While the above described construction and mode of operation of parts provides for the borrowing from the next higher wheel by any one wheel which makes a complete backward rotation, 'it may of. course occur that the borrowing must continue automatically as for example. whensone or more wheels, including that from which the initial borrowing 1s done, already stand. at

cessive tripping of transfer pawls when continued carrying is required, will take place at a time when the racks may immediately partake of excess movement, as will be understood from "the previous reference to the transfer operation in addition, but the same thing is not true when the machine is operating to perform subtraction, for as has already been explained, the borrowing move ments of wheels cannot take place in the same operation of the machine that the direct subtraction movements thereof takezero; In the performance of addition sucrear ends, as illustrated in Figs. 1, 2, 4 and -7 of the drawings.

cases where borrowing is to continue,v

which would mean that the wheel initially borrowed from would, as a result of such borrowing, pass the zero point. Hence the latches 411 are put under control of the wheels as follows: A series of latches E of bell crank form are independently pivoted in position to have. their downwardly extending varms lie in the several paths of movement of the transfer projections 9 on the wheels and their upwardly andrearwardly extending arms in the'paths of rearward movement of the studs D, respectively, such rearwardly extending arms being formed at the ends as catches to engage said studs. The result of this arrangement is that when any wheel comes to the zero position its stud 9 contacting with the depending arm of the associated latch E will-displace the latter to clear the path of the stud D- of the next lower latch 411. Consequently, if that latch is tripped by displacement of its associated transfer pawl, it may swing rearwardly a suflicient extent to displace the next higher pawl by the action of i the stud D against the abutment lug D of such pawl. The result is, therefore, that the rack belonging to the wheel of still higher order will be released from the restraint of the pawl and so the borrowing will properly continue- When a wheel is reached which is not standing at zero its latch E is, of course,

occupying eflective position which will prevent the full rearward swing of the next lower latch 411 and hence stop the borrowing, as illustrated in Fig. 7. In such case this next lower latch moves a limited extent sufficient to hold out the associated pawl, but being then arrested by the latch E, cannot move far enough to affect the next higher pawl, which will then only be displaced in the event of the associated wheel being turned far enough in addition to the borrowing movement to carry it past the zero point, but the next lower latch 411'plays no part in this because meantime it will have been restored to normal in the manner already explained'and the trippingof the higher pawl will be simply a direct tripping by action of the transfer projection 9 against the nose of the pawl.

When the machine is operating to add,

the-latchesE should be held displaced so as to prevent their lower ends from interfering with forward rotation of the wheels.

Therefore, a comb plate F is pivotally mounted by suitable side arms on one of the cross rods 200 of the machine, said plate having a rearwardly projecting finger F for each one of the latches" E and so when the plate is rocked rearwardly all said latches will be displaced. The lower arms of the latches are connected by springs e plate is controlled by a lever G, Fig. 2, pivoted intermediate its ends and having, in its forwardly projecting arm a cam slot 9 embracing a stud f on the left hand side piece of the comb plate. The rearwardly projecting arm of'said lever is slotted to embrace a stud a on the subtraction key A. It will be remembered that this key is normally upheld by the spring a, hence the lever is normally upheld as to its rearwardly extending arm and its'forwardly extending arm normally depressed, as illustrated in Fig. 1, so that the stud f is at the upper end of the slot 9, which is the end nearest the pivot of the lever. Consequently the comb plate is normally, held rearward and the latches E maintained by it in non-effective position. Depression of the subtraction key rocks the lever and the resultant cam action of the inner edge of the slot g-upon the stud f forces the comb plate forward, thus releasing the latches and drawing them yieldingly to effective position. Of course, if at such time any transfer projection 9 stands at the zero position the associated latch E -will be prevented from assuming such position, but upon the turning backward of. the wheel carrying such projection the latch will be drawn by its spring into effective position.

The disabling of latches E in the manner the full lines indicate the limit of such movement when the machine is subtracting. When the dotted line position is assumed the cross rod 902 constitutes astop for limit ing the rearward, swing of the latches 411 and preventing their studs D from acting upon the abutment'lugs D of higher order pawls. When the full line position is assumed rearward swing of the latches is permitted sufficient to displace such 'pa-wls under conditions such as heretofore men-' tioned. Two different rearward positions of the bail are determined by the abutment of a stud h on the branch 902 of the left I 65 lever 22 hand side of the bail, against a cam edge g of the rearwardly extending arm of lever G. Whenthe subt-raction lever is elevated and this rearwardly extending arm of the lever correspondingly elevated the lower portion of said cam edge stands in front of said stud, such portion of such cam edge being further removed from'the pivot of the lever and consequently acting to pre- 10 vent the bail swinging as far back as when a higher portion of said cam edge nearer the pivot of the lever is directly in front of the stud h. Depression of the subtract-ion key 'brings such higher portion of the cam edge in front of the stud, as illustrated in Fig. 2 and consequently the bail may then take up a position fartherrearward under actuation of its spring 0 When depressed the subtraction key is held down by a pivoted locking arm I, Figs. 1 and 2, which is loosely mounted upon a rock shaft 14 and drawn toward the key by a spring 71, the stem of the key having a square notch (1 adapted to be entered by the curved and forwardly directed upper end of said locking arm, as illustrated in Fig. 2. The key will be indefinitely locked down as is of course desirable, inasmuch as repeated subtraction operations will often 3 be in order and it would be inconvenient to 'haveto operate this key each time. Preferably therelease of the key is effected by depression of either the total or subtotal I key. The total key 265 is as usual mounted 5 upon the upper end of a bell crank lever 227 which, in company with an arm secured to the same rock shaft, operates the usual bail for connectively displacing the latches 415, said bail comprising a cross rod 209 and side pieces 216, one of which appears in Figs. 1 and 2. On this side piece of the bail there is a stud 2' which, when the bail is drawn rearward by depression of the total key, operates upon the locking arm I to diskey, the latter immediately rising under actuation of its springs a. Depression of the subtotal key 265 has a like effect, said key surmounting a bell crank lever 227*, to which is jointed a bar 216 having a lug y" to engage a stud on the lever 227. It will be seen that through these connections depression of the subtotal key results in rocking the grand total key lever the same as depression of the grand total key.

The connections controlled by the total and subtotal keys are somewhat modified as compared with those ordinarily found in Burroughs machines, such modification 50 being for the purpose of preventing depression of the subtraction key causing depression of the total key. The latter is, as usual,

connected with a link 911, the latter slotted at its u per end to embrace a stud on the Instead of being simply pivoted the.

place the same and release the subtraction at its lower end ,to" the pitman 914, as is usually the case, this link at its lower end is longitudinally slotted, as shown at m, Figs. 1 and 2, to embrace a stud n on the pitman and a spring 0 connects said stud 70 with the link. It will be seen that with this arrangement the pitman can be lowered independently of the link against the stress of the spring 0, and this is what takes place when the subtraction key is depressed. At the same time depression of the total or subtotal key will cause lowering of the pitman as usual. The function of the upper slot of the link is as usual to permit lowering of'the link and pitman independently of so the total key for the purpose of producing an effective engagement of the lower branch of the pitman with the lower stud 958 on the register frame. In the case of a subtotal such independent movement is pre- I is important in connection with subtraction as well as'in connection with addition. The

means ordinarily employed for so looking out the total and subtotal, keys'after one or more items have been accumulated will also serve to lock outsaid keys after one or more items have been subtracted. While this is not essential in the case of simple borrowing, it is important when there hasbeen continued borrowing. While in the case of simple borrowing the correct remainder would not appear on the number wheels or dials until a blank stroke of the operating handle had been taken, yet the" printing of 1 the correct remainder would take place,

even though, no blank stroke was taken prior to depressing the total or subtotal key. ,In the case of addition the racks must of course be restored to normal before the machine 1 is operated to take a total, for otherwise the printed total would be one numeral short in any decimal place where a trans er should show. But in the case of subtractionl the situation is reversed and the shortage in returning to zero is the desired thing. Consequently it would not be necessary to have a rack which had partaken of its transfer advance, restored to normal by a sepa-- rate operation of the machine, but the ,depression of total or subtotal key .would permit such rack to run down until .the wheel tame to the zero stop which, on account of the advanced osition of the'rack at the start, would not ring to the printing linethe type corresponding with the numeral displayed on the wheel, but the type set up would bea unit less in value. Then, of course, at the conclusion of the operation in the case of a subtotal the numeral corre The means for looking out the total and subtotal keys comprises the familiarspringdrawn bail 424, the left side piece of which has a broadened upper end adapted to move.

under a stud 27 on the total key lever 227. This takes place as usual by reason of the depressipn of amount keys, the detent strips 214 havlng downwardly turned portions to act against the-.cross-bar of said bail, but the bail is also under control of the transfer latches 411 and when any one of the same is displaced as a result of the tripping of the associated transfer pawl in an adding operation the bail is blocked by such latch against return to forward normal position. Consequently the total key is locked against depression and of course the subtotal key likewise. As before explained,

. the rearward swing of the latches 4.1.1 as

a result of initial borrowing is slight as compared with the rearward swing when continued borrowing is to take place. The

movement of said latches for initial borrowing need not be sufiicient to hold the bail 424 in position for locking out the total and subtotal keys, but obvlously the rearward swing of latches for continued borrowing will result in blocking the bail and locking out the total and subtotal keys.

As the transfer pawls cannot serve to limit backward rotation of the wlTeels as in a machine which simply adds, it becomes necessary to provide a separate zero stop device under control of the total and subtotal keys. In the present instance a comb plate R is pivoted to the sides of the register frame 910, as shown in Figs. 1 and 2, said one for each'of the who Is and adapted plate having forwardly pgojecting fingers,

when the plate is swung orward to enter the respective \paths of the transfer projections 9 on said wheels. At its right hand endsaid plate has a rearwardly projecting arm 1" which is connected by an irregularshap'ed link It with a crank 'arm 14: secured to the rock sliaft 14 near its right hand end. Near its left hand end'said rock shaft carries a similar crank arm 14 con-' nected b a link 14 with the bell crank 227. It will tions depression of the 10mm subtotal key will result in rocking the said comb ,plate forward and projecting its fin ers into the However, in

e seen that through these connec strained by latches 717. Pawls 718 on an oscillating bail individually actuate 'the latches to release the hammers and are controlled by the type-carrying" levers 611 in the ordinary way. To the right of the series of type-carrying levers there is located a special type-carrying arm S, Figs. 10 and 11, which is pivotally mounted at its rear end preferably on the right side piece of the usual ribbon frame 511. This arm carries type plates'618 having as here shown three special character types, the lower one of which is formed to print the number sign (it) indicating an amount neither added nor subtracted, whereas the middle type is formed to print the minus sign' to. indicate a subtracted amount 'or a subtrahend,

and the upper type is formed to print star to indicate a total or subtotal. These type plates are driven against the platen in the same way that amount type platesare so driven, there being provided an extra set of impression devlces, such as those I already specified, but of course these extra impression devices do .not come into play except when either the total, subtotal, subtraction, or elimination key is depressed. The pawl of this extra set of impression devices is disabled in a similar way to that in which pawls of the other sets of impression devices are disabled. Thus an arm 229 secured to a rock shaft 206 is formed at its lower end with an inclined or cam edge 8 for disabling the pawl, said arm being normally held back against the shaft 600 by a in upward movement by the abutment againstsaid rock shaft of an upstanding arm S andis guided in its movements by an arc-shaped slot .9 formed in it and engaged by a stud s fastened in the side piece of the ribbon frame. a

The reference numeral 221 designates the elimination key which slides vertically through the keyboard plates, Fig. 1, and is further guided by the engagement of a slot u in its lower portion with a stud on the left hand side piece of the main frame of the machine, said key being normally upthe pinions 916 and racks 61.0. The stem of the key is formed with a cam rise .221 adapted when the key is depressed to act against a roller 9 on the arm 229*, thus swinging said arm rearwardly. The accompanying rearward swing of the arm 229 removes the cam edge 8 from the path of the pawl 71S and thus permits the hammer to drive the number sign type against the platen. The elimination key is caught and held down by a pivoted spring-drawn detent 221 which is displaced at the conclusion of an operation by the same bail which releases depressed amount keys. The said bail as usual comprises side pieces 219 and a cross rod 209' and the left side piece car ries a stud c which is embraced by'a slot in the rear end of a link 226 coupled at its forward end to the total key bell crank lever 227 as shown in Fig. 1. This link has a shoulder w at an intermediate point standing in front of a'studw on the arm 229 Depression of the total or subtotal key thrusts the link226 rearward causing its shoulder-w to swing the arms 229 and 229* rearward, thus permitting the pawl 718 to act, and the rocking of the key-releasing bail, by depression of either of said keys,

causes the arm T to be swung down. The

upright arm S onthe special type carrier has an inclined forward edge and a roller 13 on the crank arm T acting against such edge with a camming effect forces the type carrier downward, positioning the star type at the printing line. Thus the imprint of a total or subtotal will be characterized by the printing inassociation therewith of the star or asterisk. This special character may also be printed before starting a list to indicate that the machine was clear at such time, the star then appearing alone in the example shown in Fig. 12. In that same'example the first imprint thereafter is of an unadded and unsubtracted number, and has the number sign printed in association with it to so indicate.

The subtraction key stem carries a' stud m, Fig. 1, which engages the bifurcated forward end of a lever X pivoted intermediate its ends just under the keyboard and formed at its rear extremity to act with a camming effect upon the roller q, Depression of the subtraction key thus has the effect of swinging the arms 229 and 229 rearwardly so as to permit the special hammer to act and in this case said arms swing farther rearward than by depression of either the total, subtotal or elimination keys. The arm 229, Figs. 10 and 11, has pivotally connected with it the forward end of a thrust bar Y 'hend is a subtotal.

the printing line, as indicated in Fig. 11.

Thus there will be printed in association with a subtrahend, a minus sign as indicated in the example of work shown in Fig. 12, wherein the' star indicates that the amount printed just above the first subtrain said example is a reduced grand total or remainder. c a

While the construction here shown "and describedwill be seen to be well adapted for thoroughly fulfilling the objects primarily stated, it is to be understood that the invention is not limited to this particular .form of embodiment but may be otherwise carried out.

lVh'at is claimed is: r

1. I11 a machine of the character described, the combination of differentially movable reciprocating racks, wheels movable into and out of engagement therewith, transfer mechanism for causing a complete rotation of any wheel in either direction to result in an increment of movement of the next adjacent wheel of higher order, and means for reversing the order ofengagement and disengagement between wheels and racks to provide for movement of the wheels in either dlrection by the racks.

2. In a maclnne of the character described,

The last amount shown the combination of differentially movable' reciprocating racks, wheels movable into and out of engagement therewith, spring transfer mechanism for causing a complete rotation of any wheel in either direction to re- .sult inan increment of movement of the next adjacent wheel of higher order, and means for reversing the order of engagement and disengagement between wheels and racks to provide for movement of the wheels in either direction by the racks.

3. In a machine of the character described, the combination of differentially movable reciprocating racks and carriers, the racks having-an increment of movement independ ent of the carriers, means normally preventing such independent movement of racks, wheels movable into and out'of engagement with the racks, and means for reversing the order of engagement and dis engagement between racks and wheels to provide for movement of the wheels by the racks in eitherdirection, with provisions for causing complete rotation of any wheel in either direction to permit independent movement of the rack of the adjacent wheel of higher order for transfer purposes.

4. In a machine of the character described,-

the combination of difi'erentially' movable reciprocating racks and carriers, the racks having an increment of movement independent of the carriers under spring-aetuation, means normally preventing such independent movement of racks, wheels movable into and out of engagement with the racks, and means for reversing the order of engage, ment and disengagement between racks and wheels to provide for movement of the wheels by the racks in either direction, with provisions for causing complete rotation of any ,wheel' in'either direction to permit independent movement of the rack of the adjacent wheel'of higher order for transfer purposes.

5. In a machine of the character described, the combination of differentially movable reciprocating racks and carriers, the racks having an increment of movement independent of the carriers, pawls normally preventing such independent movement of racks, wheels movable into and out of en'gagement with the racks and having projections to displacesaid pawls upon complete rotation of wheels in either direction, and means for reversing the order of engagement'and disengagement between racks and wheels to provide for movement of the wheels in either direction by the racks.

6. In amachine of the character described, the combination of diflerentially movable reciprocating racks and carriers, the rackshaving an increment of movement independent of the carriers under spring-actuation, pawls normally preventing such independent movement of racks, wheels movable into and out of engagement with the racks and having'projections to displace said pawls upon complete rotation of wheelsin either direction and means for reversing the order of engagement and disengagement between racks and wheels to provide for movement of the wheels in either direction by the racks.

7. In a machine of the characterrdescribed, the combination of differentially movable reciprocating racks and carriers, the racks having an increment of movement independent of the carriers, pawls normally preventing such independent movement of racks, wheels movable into and out of engagement with the racks and having projections to displace said pawls upon complete rotation of wheels in either direction, meansfor reversing the order of engagement and disengagement between racks and wheels to provide for' movement of the wheels in either direction by the racks, and latches for holding the pawls displaced until the rack carriers return home.

8. In a machine of the character described, the combination of differentially movable reciprocating racks and carriers,

means for reversing the order of engagement and disengagement between racks and wheels to provide .for movement of the wheels in either direction by' the racks,

latches for holding the pawls displaced un.- til the rack carriers return home, and means for retracting the latches before the racks are advanced an increment of movement by their carriers. p i

9. In a machine of the character described, the combination of differentially, movable reciprocating racks and carriers, the racks having an incrementof movement independent of the carriers, pawls normally preventing such independent. movement of racks, wheels movable into and out of enagement with the racks and having proections to displace said pawls upon complete rotation. of wheels in either direction, means for reversing the order of engagement and disengagement between racks and wheels to provide for movement of. the

wheels in either direction by the racks,

latches for holding the pawls displaced, said latches adapted under control of the wheels to displace pawls of hi her order.

10. In a machine 0 the character described, the combination of differentially movable reciprocating racks and carriers, the racks having an increment of movement independent of the carriers, pawls normally preventing such independent movement of racks, wheels movable into and out of engagement with the racksand having projections to displace said pawls ,upon complete rotation of wheels in either. direction, means for reversing the order of'engagement and disengagement between racks and wheels to providefor movement of the wheels in either direction by the racks, latches fer holding the pawls displaced until the rack carriers return home, said latches adapted to displace pawls of higher order, and means controlled by the wheels when turned in one'direction for restraining the latches from performance of their last-mentioned function except when the wheels are at zero.

11. In a machine of the character described, the combination of diflerentially movable reciprocating racks and carriers, the racks having an increment of movement a independent of the carriers, pawls normally preventing such independent movement of racks, wheels'movable into and out of enagement with the racks and having proections to displace said pawls upon complete rotation of wheels in either direction,

.means for reversing the order of engagement and disengagement between racks and wheels to provide for movement of the wheels in either. direction by the racks,

latches for holding the pawls displaced until the rack carriers return home, said latches adapted to displace pawls of higher order, and latches for said' pawl-latches to I scribed, the combination of differentially movable reciprocating racks and carriers, the racks havlng an increment of movement I independent of the carriers, pawls normally preventing such independent movement of racks, wheels movable into and out of em gagement with the racks and having projections to displace said pawls upon complete rotation of wheels in either direction,-

means for reversing the order of engagement and'disengagement between racks and wheels to provide for movement of the wheels in either direction by the racks, latches for holding the pawls displaced until the rack carriers return home, said latches having elongated studs to act upon the pawls of higher order and displace the same, andlatches to engage said studs and restrain the pawl-latches from displacing adjacent pawls but themselves displaced by the transfer projections on the wheels.

13. In a machine of the character described, the combination of differentially movable reciprocating racks and carriers, the racks having an increment of movement independent of the carriers, pawls normally preventing such independent movement of racks, wheels movable into and outof engagement with the racks and having projections to displace said pawls upon complete rotation of wheels in either direction, means for reversing the order of engagement and disengagement between racks and wheels to provide for movement of the wheels in either direction by the racks, latches for holding the pawls displaced until the rack carriers return home, said latches adapted to displace pawls of higher order, means controlled by the wheels when turned in one direction for restraining the latches from performance of their last-mentioned function except when the wheels are at zero, and,

means for disabling said restraining means altogether when the wheels are to be turned in the opposite direction,

14. In a machine of the character described, the combination of differentially movable reciprocating racks and carriers, the racks having an increment of movement independent of the carriers, pawls normally preventing such independent movement of racks, wheels movable into and out of engagement with the racks and having projections to displace said pawls upon complete rotation of wheels in either direction, means for reversing the order of engagement and either direction by the racks, latches for.

holding the pawls displaced until therack carriers return home, said latches adapted to I displace pawls of higher order, latches for said pawl-latches to restrain the latter from performance of their last-mentioned function but,displaced by the transfer projections on the wheels, and means for displac ing said pawl latches independently of the wheels when the latter are to be turned in the opposite or adding direction.

15. In a machine of .the, character described, the combination of differentially movable reciprocating racks and carriers, the racks havlng an increment of movement independent of the carriers, pawls normally preventing such independent movement of racks, wheels movable into and out of engagement with the racks and having projections to displace said pawls upon complete rotation of wheels in either direction, means for reversing the order of engagement and disengagement between racks and wheels to provide for movement of the wheels in either direction'by the racks, latches for holding the pawls displaced until the rack carriers return home, said latches having elongated studs to act upon the pawls of higher order and displace the same,latches to engage said studs and restrain the pawl-latches from displacing adjacent pawls but themselves displaced by the transfer projections on the Wheels, and means for displacing said pawl latches independently ofthe wheels when the latter are to be turned in'the opposite or adding direction. j

'16. In. a machine of the character described, the combination of differentially movable'reciprocating racks 'and carriers, the racks having an increment of movement independent of the carriers, pawls normally preventing such independent movement of racks, wheels movable into and out of engagement with the racks and having projections to displace said pawls upon com plete rotation of wheels in either direction,

means for reversing the order of engagethen otherwise limiting movement of the pawl-latches to prevent displacement by them of pawls of higher order.

17. In a machine of the character de-- scribed, the combination of differentially movable reciprocating racks and carriers, the racks having an increment of movement independent of the carriers, pawls normally preventing such independent movement of racks, wheels movable into and out of engagement with the racks and having projections to displace said pawls upon complete rotation of wheels in either direction, means for reversing the orderof engagement and disengagement between racks and wheels to provide for movement of the wheels in either direction by the racks, latches for holding the pawls displaced until the rack carriers return home, said latches adapted to displace pawls of higher order,

latches for said pawl-latches to restrain the latter from performance of their last-mentioned function but displaced by the transfer projections on the wheels, means for displacing said pawl latches' independently of the wheels when the latter are to be turned in the opposite .or adding direction, and

means for then otherwise limiting movement of the pawl-latches to prevent displacement by them of pawls of higher order.

18. Ina machine of the character described, the combination of diiferentially movable reciprocating racks and carriers, the racks having an increment of movement independent of the carriers, pawls normally preventing such independent movement of racks, wheels movable into and out of engagement'with the racks and having projections to displace said pawls upon com-- plete rotation of wheels in .either. di-

rection, means for reversing the orderof engagement and disengagement between racks and wheels to provide for movement of the wheels ineither direction by the racks, latches for holding the pawls displaced until the rack carrlers return home, said latches adapted to displace pawls of higher order, means controlled by the wheels when turned in one direction for restraining the latches from performance of their last-- mentioned function except when the wheels areat zero, means fordisabling said restraining means altogether when the wheels are to be turned in the opposite direction, and means for restoring the pawl-latches adjustable to limit movement thereof and prevent'displacement thereby of pawls of higher order when the wheels are to be turned in the adding direction,

19. In a machine of the character described, the combination of differentially movable reciprocating racks and carriers, the racks having an increment of movement independent of the carriers, pawls normally preventing such independent movement of racks, wheels movable into and out of enracks, wheels movable into and out of engagement with the racks and having projections to displace saidpawls upon complete rotation of Wheels in either direction, means for reversing the order of engagement and disengagement between racks and wheels to provide for movement of the wheels in either direction by the racks, latches for holding the pawls displaced until the rack carriers return home, said latches adapted to displace pawls of higher order, latches for said pawl-latches to restrain the latter from performance of their last-mentioned function but displaced by the transfer projections on the Wheels, means for displacing said pawl latches independently of the wheels when the latter are to be turned in the opposite or adding direction, and means for restoring the pawl-latches adjustable to limit movement thereof and prevent displacement thereby of pawls of higher order when the wheels are to be turned in the adding direction.

20. In a machine of the character de-' scribed, the combination of difierentially movable reciprocating racks and carriers, the racks having an increment of movement independent of the carriers, pawls normally preventing such independent movement of gagement with the racks and having projections to-displace said pawls uponcomplete rotation of wheels in either direction, connections for moving the wheels out of and into engagement with the racks and 'operat-ing normally to keep the wheels and racks disengaged during advance of the racks and engaged during return of, the'racks but adjustable to effect reversal of this order of engagementand disengagement, and a key for effecting this changed adjustment of said connections. a

21. In a machine of the character described, the combination of differentially movable reciprocating racks andv carriers, the racks having an increment of movement independent of the carriers, pawls normally preventing such independent movement of, racks, wheels movable into and out'of engagement with the racks and having projections to displace said pawls upon complete rotation of wheels in either direction,

connections for moving the wheels out of and into engagement with-the racks and operating normally to keep the wheels and racks disengaged during advance of the racks and engaged during'return of the racks but adjustable to effect reversal of this order of engagement and disengagement, a key for effecting this changed adjustment of said connections, latches for holding the pawls displaced until the rack-carriers re-' turn home, said latches adapted to displace pawls of higher order, and means controlled by the wheels and the aforesaid key for re-- racks, wheels movable into and out of en gagement with the racks and having projections to displace said pawls upon complete rotation of Wheels in either direction, connections for moving the wheels out of and into engagement with the racks and operating normally to keep the wheels and racks disengaged during advance of the racks and engaged during return of the racks but adjustable to etftect reversal of this order of engagement and disengagement, a key for effecting this changed adjustment of said connections, latches tor holding the pawls displaced until the rack carriers return home, said latches adapted. to displace pawls of higher order, normally disabled means for restraining the latches, and means operated by said key to enable said restraining means, the latter adapted to be again disabled by the transfer projections on the wheels.

23; In a machine of the character described, the combination of diii'erentially movable reciprocating racks and carriers, the racks having. an increment of movement independent of the carriers, pawls normally preventing such independent movement of racks, wheels movable into and out of engagement with the racks and having projections to displace said pawls upon complete rotation of wheels in either direction, connections for moving the wheels out of and into engagement withthe racks and operating normally to keep the wheels and racks disengaged during advance of the racks and engaged during return of the racks but adjustable to efiect reversal of this order of engagement and disengagement, a

key for efi'ecting this changed adjustment of said connections, latches for holding the pawls displaced until the rack-carriers return home, said latches adapted to displace pawls of higher order, latches for said pawl latches to restrain the latter from displacing pawls of higher order, and means normally disabling said restraining latches, but itself disabled by operation of said key, the 'restraining latches then assuming effective position but adapted to be displaced by,the transfer-projections of the wheels.

24:. In a machine of the character described, the combination of dili ereiitially movable reciprocating racks and carriers, the racks having an increment of movement independent of the carriers, pawls normally preventing such independent movement of racks, wheels movable into and out of engagement with the racks and having projections to displace said pawls upon complete rotation of Wheels in either direction, connections for moving the wheels out of and into 'engagementwith the racks and operating normally to keepthe wheels and racks disengaged during advance of the racks and engaged during return of the racks but adjustable to effect reversal of this order of engagement and disengagement, a key for etfecting this changed adjustment of said connections, latches for holding the pawls displaced'until the rack-carriers return home, said latches adapted to displace pawls of higher order, latches for said pawl latches to restrain the latter from displacing pawls of higher'order, means normally disabling said restraining latches, but itself disabled by operation of said key, the restraining latches then assuming effective position but adapted to be displaced by the transfer-projections of the wheels, and means for restor ing the pawl-latches normally limiting movement thereof to preventdisplacement of pawls of higher order but adjustable by said key to permit sufficient-movement of,

the pawl-latches for such purpose.

25. In a machine of the character described, the combination ct differentially movable reciprocating racks and carriers, the racks having an increment of movement independent of the carriers, pawls normally preventing such independent movement of racks, wheels movable into and out of engagement with the racks and having projec-- tions to displace said pawls upon complete rotation of wheels in either direction, connections for moving the wheels out of and into engagement with the racks and operating normally to keep the wheels and racks disengaged during advance of the racks and said key whereby operation of the latter causes the comb-plate to withdraw and permit the restraining latches to assume eilective position, saidlatches then adapted to be displaced by the transfer projections on the wheels.

26; In a machine of the character described, the combination of differentially movable reciprocating racks and carriers, the racks having an increment of movementindependent of the carriers, pawls normally preventing such independent movement of racks, wheels movable into and out of enagement with the racks and having proections to displace said pawls upon complete rotation of wheels in either direction, connections for moving the wheels out of and into engagement with the racks and operating normally to keep the Wheels and racks disengaged during advance of the racks and engaged during return of the racks but adjustable to effect reversal of this order of engagement and disengagement, a key for effecting this changed adjustment of said connections, latches for holding the pawls displaced until the rack-carriers return home, said latches adapted to displace pawls of higher order, normally disabled means for restraining the latches, means operated by said key to enable said restraining means, the latter adapted to be again disabled by the transfer projections on the Wheels, a restoring bail for the pawl latches normally limiting movement thereof to prevent displacement of pawls of higher order, but adjustable by said key to permit sufficient movement for such purpose, and means 7 for reciprocating the bail.

27. In a machine of the character described, the combination of differentially movable reciprocating racks and carriers, the racks having an increment ofmovement independent of the carriers, pawls normally preventing such independent movement of racks, wheels movable into and out of'engagement with the racks and having projections to displace said pawls upon complete rotation of wheels in either direction, connections for moving the wheels out of and into engagement with the, racks and operating normally to keep the wheels and racks disengaged during advance of the racks and engaged during return of the racks but adjustable to efiec t reversal of this order of engagement and disengagement, a key for'efiecting' this changed admeans operated by justment ofsaid connections,i latches for holding the pawls displaced until the rackcarriers return home, said latches adapted to displace pa-Wls of higher order, normally disabled means ,for'restraining the latches, said key to enable said restraining means, the latter adapted to be .55 again disabled by the transfer projections on the wheels, a restoring bail for the pawl latches normally limiting movement thereof to prevent displacement of pawls of higher order, a cam lever engaging said bail and engaged by said key whose operation there'- by adjusts the bail to permit sufiicient move ment of the pawl latches to displace pawls of higher order, andmeans for reciprocating the bail. i

28. In a machine of the character described, the combination of difl'erentially movable reciprocating racks and carriers, the racks having an incrementof movement independent of the carriers,pawls normally preventing such independent movement of racks, wheels movable into and out of engagement with the'racks and having projections to displace said pawls upon complete rotation of wheels in either direction, connections for moving the wheels out of and into engagement with the racks and operating normally to keep the wheels and racks disengaged during advance of the racks and engaged during return, of the racks but adjustable to effect reversal of this order of engagement and disengagement, a key for efi'ecting this changed adjustment of said connections, latches for holding the pawls displaced until the rackcarriers return home, said latches adapted to displace pawls of higher order, pivoted latches adapted to restrain the pawl latches from displacing pawls ofhigher order, a movable comb-plate for holding said restraining latches normally displaced, a restoring bail for the pawl-latches normally limiting movement thereof to prevent dis- 1 said lever engaged by said key whereby operation of the latter adjusts the bail to permit' sufficient movement of the pawl-latches to displace pawls of higher order and causes the comb-plate to withdraw permitting the restraining latches to assume effective position subject to displacement byftransfer projections of the wheels, and means for reciprocating the bail.

29. In a machine of the character described, the combinat-ion of diiierentially movable reciprocating racks and carriers, the racks having an increment of move ment independent of the carriers, pawls nor,- mally preventing such independent movement of racks, wheels movable into and out of engagement with the racks, and having projections to displace said pawls upon complete rotation of wheels in either direction, meansv for reversing the order of engagement and disengagement between racks and wheels to provide for movement of the wheels in either direction by the racks,

latches for holding the pawls displaced until a the rack carriers return home, and means for retracting the latches before the racks are advanced an increment of movement by their carriers, said means comprising an oscillating bail-t0 act on the-latches, .a vibrating arm and a Wipe pawl on the latter to engage the pawl.

30. In a machine of the character described, the combination of difl'erentially movable reciprocating racks and carriers, the racks having an increment of movement independent of the carriers, pawls normally preventing such independent movement of racks, wheels movable into and out of engagement with the racks and having projections to displace said pawls upon complete rotation of wheels in either direction, connections for moving the wheels out of and into engagement with the racks and operating normally to keepthe wheels and racks disengaged during advance of the racks and engaged during return of the racks but adjustable to effect reversal ofv of pawls of higher order, but adjustable by said key to permit sufficient movement for such purpose, and means for reciprocatlng the bail, comprising a vibrating arm and a wipe-pawl thereon.

31., In a machine of the character described, the combination. of differentially movable reciprocating racks and carriers, the racks having an increment of movement independent of the carriers, pawls normally preventing such independent movement of racks, wheels movable into and out of engagement with the racks and having projections to displace said pawls upon complete rotation of wheels in either direction, connections for moving the wheels out of and into engagement with the racks and operating normally to keep theywheels and v racks disengaged during advance of the racks and engaged during return of the racks but adjustable to effect reversal of this order of engagement and disengagement, a key for effecting this changed adjustment of said connections, latches for holding the pawls displaced until the rackcarriers return home, said latches adapted to displace pawls of higher order, normally disabled means for retraining the latches, means operated by said key to enable said restraining means, the latter adapted to be again disabled by the transfer projections on the wheels, a restoring bail for the pawl latches normally limiting movement thereof to prevent displacement ofpawls of higher order, a cam lever engaging said bail and engaged by said keywhose operation thereby adjusts the bail to permit sutficient movement of the pawl latches to displace pawls of higher order, and means for reciprocating the bail comprising a vibrating arm and a wipe-pawl thereon key to en- 32, In a machine of the character described, the combination of diiferentially movable reciprocating racks and carriers, the racks having an increment of movement independent of the carriers, pawls normally preventing such independent movement of racks, wheels movable into and out of engagement with the racks and having projections to displace said pawls upon complete rotation oftwheels in either direction, connections for moving the wheels out of and into engagement with the racks and op: erating normally to keep the wheels and racks disengaged during advance of the racks and engaged during return of the racks but adjustable to effect reversal of this order of engagement, and disengagement, a key for efiecting this changed adjustment ofsaid connections, latches'for holding the pawls displaced until the rackcarriers return home, said latches adapted to displace pawls of higher order, pivoted latches adapted to restrain the pawl latches from displacing pawls of highenorde/r, a movable comb-plate for holding said restraining latches'normallydisplaced, a restoringf'bail for the pawl-latches normally limiting movement thereof to prevent displacement of pawls of higher order, a lever having a cam-slot engaging the said combplate and a cam edgeengaging said-bai said lever engaged by said key whereby operation of the latter adjusts the bail to permit suflicient movement ofthe pawl-latches to displace pawls of higher order and causes the comb-plate to withdraw permitting the restraining latches to assume efiective posi tion subject to displacement by transfer projections of the wheels, and means for reciprocating the bail comprising a vibrating arm and a wipe-pawl thereon.

33. In a machine of the character described, the combination of differentially movable reciprocating racks and carriers, H

jections to displace said pawls /u-pon complete rotation of wheels in either direction,

means for reversing the order of engagement and disengagement between racks and wheels to provide for movement of the wheels in either direction by the racks,

ack carriers return home, an means for retracting the latches before the racks are advanced an increment of-movement by their carriers, said means comprising a spring-drawn oscillatory bail to act on the latches, an oscillatory main driving arm, a spring-held toggle link pivotally mounted thereon and'limited as to movement in one direction, and a wipe-pawl on said link leltches for holding the pawls displaced until

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