US2160296A

US2160296A - Algebraic totalizer

Info

Publication number: US2160296A
Authority: US
Publication date: 1939-05-30
Anticipated expiration: 1956-05-30

Description

y 1939- o. J. S-UNDSTRAND 2,160,296

ALGEBRAIC TOTALI ZER Filed March 31, 1934 2 Sheets-Sheet l INVENTOR.

OscarJ Sundsimnd BY 6 I 4 'Q ATTORNEYS.

o. J. SUNDSTRAND ALGEBRAIC TOTALIZER May 30, 1939. 2,160,296

2 Sheets-Sheet 2 Filed March 51, 1934 IN VEN TOR.

m (gwlSunqstrand.

' ATTORNEYS.

Patented May 30, 1939 UNITED STATES PATENT OFFICE ALGEBRAIC TOTALIZER Application March 31,

16 Claims.

The invention relates to computing machines and more particularly to adding and subtracting totalizers therefor.

In computing machines of the type illustrated in my United States application Serial No. 118,628, filed June 26, 1926, as well as in the application of Birney Dysart Serial No. 565, filed January 19, 1925, (Patent No. 2,014,560) means is provided to rotate the pinion of lowest order, in either an additive or a subtractive direction, a distance corresponding to one unit for the purpose of introducing what has come to be termed a fugitive one. In these machines the so called fugitive one introducing means operates automatically as an incident to each passage of the pinion of highest order through zero that is, if additive amounts be entered in the counter in excess of. a subtractive or negative quantity already stored therein, the pinion of highest order will be caused to move from a negative to a positive condition, or, in other words, it will pass through zero, and as a consequence, the fugitive one introducing means will be actuated to advance the pinion of lowest order one unit, in the same direction as characterized the actuating movement of the pinion of highest order.

Since the introduction of the fugitive onein such machines invariably occurs momentarily after passage of the wheel of highest order through zero, in either direction of movement, it is said that the amount set up on the pinions always represents the true algebraic sum of the computation. However, this characteristic of immediately introducing an additional or fugitive unit as a consequence of each passage of the pinion of highest order through its zero position will, at times, give rise to an error. For example, when the machine is operated for the accumulation of a succession of exclusively additive, or exclusively subtractive amounts, in excess of the capacty of the machine, the pinion of highest order will necessarily pass through zero as a consequence of which, a fugitive one will erroneously be introduced in the wheel of lowest order. This error has come to be designated in the art as an "overcarry of one in the pinion of lowest order.

It is accordingly, an object of the present invention to provide new and improved means for effecting a correct algebraic total in machines of the class described without rotating the pinion of lowest order to introduce a fugitive one.

Yet another object of the invention resides in the provision of means operable as an incident 1934, Serial No. 718,328

to a total taking cycle of operations to produce a correct algebraic total.

A further object of the invention is to provide an algebraic totalizer such that the actuating element of the totalizer pinion of lowest order 5 will automatically move one unit in excess of theamount represented on said pinion as an incident to a total taking operation whenever the totalizer is in the state opposite that in which it was during the preceding total taking operation.

Another object of the invention is to provide an algebraic totalizer including a set of pinions,

a set of adding racks effective to accumulate positive or additive amounts on said pinions, a set of subtracting racks efiective to accumulate negative or subtractive amounts on said pinions, an adding cradle arranged to be rocked from a normal position as an incident to a passage of the pinion of highest order through zero in a positive direction of movement, a subtracting cradle arranged to be rocked from a normal position as an incident to a passage of the pinion of highest order through zero in a negative direction of movement, a part movable in one direction under the influence of said adding cradle, and in an opposed direction under the influence of said subtracting cradle, a lever operatively supported on a fixed pivot and articulated to said part in such manner as to be rendered ineffective when the part is actuated by the adding cradle and eifective when the part is actuated by the subtracting cradle, fixed lugs on the pinions numerically above the pinion of lowest order, movable lugs associated with the pinion of lowest order, and means operable by said lever to move said last mentioned lugs relatively to said lowest order pinion to permit a step of movement of the rack of lowest order in excess of that which is permitted as a consequence of the normal position of the lugs with respect to the pinion of lowest order.

Other objects and advantages will become apparent from the following description, taken in connection with the accompanying drawings in which:

Figure 1 is a fragmental elevational View of one form of machine embodying the features of my invention, the view being taken from the right hand side of the machine;

Figure 2 is a fragmental perspective view showing the pinions of highest and lowest order and certain related mechanism;

Figure 3 is a detailed perspective view of certain of the parts shown in Figure 2;

Figure 4 is an enlarged elevational view of the totalizer pinion of lowest order at the time of effecting a totaling operation in engagement with the adding racks;

Figure 5 is a view taken in the plane of line 55 of Figure 4;

Figure 6 is an enlarged elevational view of the totalizer pinion of lowest order at the time of effecting a totaling operation in engagement with the subtraction racks;

Figure 7 is an elevational view showing the means of mounting the totalizer pinion of lowest order and its articulated parts.

The invention is herein shown as embodied in a machine of the general character disclosed in Sundstrand Patents Nos. 1,198,487, 1,481,487, 1,583,102, and 1,965,611 and in my co-pending application Serial No. 118,628, filed June 26th, 1926, but it will be understood that the invention is not limited to machines of the Sundstrand type. Reference may be made to the above mentioned patents and to my co-pending application for an understanding of features not fully illustrated or described herein. Certain other features commonly employed in machines of this type and well-known in the art are more fully described and illustrated in my Patent No. 1,965,611.

A conventional platen is diagrammatically illustrated at E0 in Figure 1, and, like the corresponding part fully disclosed in my above mentioned application, may be operatively mounted in a carriage for advancing and retracting excursions of movement in proximity to a group of type bars II. The upper portions of the respective type bars are fitted with independently movable types, the bars being adapted to be raised and lowered to present any desired type at the printing point of the platen, by means more fully described in my before mentioned patents and application. Briefly, such means comprises yieldingly actuated arms operatively connected to the respective bars, the extent of movement to be imparted to any particular bar by its associated arm being controlled by a nest of stops, such, for example as the stops 42 in my Patent No. 1,583,102. The stops in turn are arranged for horizontal sliding movement under control of the amount keys of the machine so as to be projected into the path of coacting stop pinscarried by the respective type bars.

Subsequent to setting an amount, or amounts, in the keyboard, the machine is cycled either manually or by power means through the medium of a main rock shaft, such as shaft 26 of my last mentioned patent.

The movement thus imparted to the type bars is adapted to be communicated to the pinions of a totalizer generally indicated at l2 in Figure 1. Only the pinions of lowest and highest numerical order are shown in the drawings, but it will be understood that any desired number of intermediate pinions may be employed. The pinions of the totalizer [2 are arranged'to be rotated in a clockwise direction to effect addition, by means of a set of adding racks l3, one such rack being associated with each pinion. A set of subtracting racks l4 are effective to rotate the respective pinions in a counterclockwise direction for the purpose of entering subtractive amounts. The independent ones of the respective sets of racks are connected to the type bars by means of rearwardly extending arms l5, one such arm being formed on each type bar and arranged to receive both an adding and a subtracting rack.

' fer lugs fitted to, or formed on, the side faces of the respective pinions and spaced 10 teeth one from the other. To this end, each of the several racks, of both sets of racks, excepting the racks of lowest denominational order, is capable of a single step of movement independently of the arm of the type bar to which it is attached. As is shown in Fig. 1, the racks are operatively connected to their respective arms by means of pin and slot connections l5a, each of the racks normally being urged downwardly with respect to its supporting arm by means of a spring l6 acting between the rack and a downwardly extending portion ll of the arm I5 to which it is attached. Two similar bars I 8, which extend longitudinally of the totalizer in guiding and bearing relation with respect to the two sets of racks, function to restrict the transferring action of the respective racks to a single step of movement by serving as abutments for lugs formed integrally with the racks in overlying relation with respect to the bars.

As will be seen in Figs. 1 and 4, the totalizer pinions are journalled on a shaft 19, which, in turn, is arranged to be shifted in a direction normal of its axis, to cause the pinions to mesh with either the adding or subtracting racks in timed relation with the ascending or descending movement of the latter parts. The means for so shifting the pinions may be of any suitable nature, one of such means being fully shown in my aforementioned Patent No. 1,965,611,.to which reference may be had for a detailed understanding.

Referring particularly to Fig. 2 and supplementarily to Fig. 1, a cradle, hereinafter designated the Adding cradle, and comprising spaced arms 20 and 2| rigidly connected for joint movement by a bail piece 22, is journalled on a shaft 23 supported in the frame of the machine. A dog 24, structurally and functionally similar to the corresponding part shown in Figs. 14. and 15 of my Patent No. 2,088,982, is pivotally connected to arm 2| adjacent its lower end and arranged to engage the inner or forward face of its associated bar 18. A spring 25 acts to yieldably retain the dog in the position shown in Fig. 2. When the dog 24 occupies the position shown in Fig. 2, its forwardly extending nose 26, is interposed in the path of movement of transfer lugs 21 and 21a on the totalizer pinion 28 of highest numerical order.

Thus, it will be obvious that when the pinion of highest order is caused to pass through zero" while in engagement with the adding racks, one or the other of the lugs 21 or 21a will contact the nose 26 of dog 24 to disengage the latter from its normal position as shown in Fig. 2, and thus permit the cradle comprising arms 20 and 2| to rock in a clockwise direction as shown in Figure 2, under the influence of spring 25;

The lower end of arm 20 is fitted with a pin 36 which extends laterally of the plane of the arm into the path of an upstanding lug 28 formed integrally with an irregularly shaped slide 29.

The slide 29 is supported for forward and rear- Ward movement relative to the frame of the machine in a plane adjacent the plane of the pinion of lowest order by the following means:

The rear end of the slide is turned downwardly at 30 to ride upon the peripheral surface of a flanged roller 3| operatively supported in the frame of the machine, and the forward end of the slide is provided with an upwardly and rearwardly extending portion 32, an edge 33 of which slides upon the upper surface of the forward one of the bars l8.

Upward displacement of the slide is prevented by virtue of the fact that its

horizontal edges

34 and 35 slidably engage aligned notches formed in the under surface of the bars 18.

Now it will be seen that the pin 36 is effective to move the slide 29 in one direction, that is, rearwardly, as a consequence of the tripping of dog 24 by either one of the lugs on the pinion of highest order, when the latter passes through zero during an adding operation. Such tripping of the dog of highest order does not, however, effect rotation of the pinion of lowest order, for the purpose of introducing a fugitive one as is the case in the before mentioned Dysart application, and, in my own application Serial No. 118,628. To insure against such operation, the adding and subtracting racks of units order are not supported with their integrally formed lugs in spaced relation above the bars IE, but on the contrary, those lugs, as indicated at 360. and 31 in Figure 1, extend downwardly, a sufiicient distance to bear upon the respective bars 18 when the machine is in its normal condition, that is, when the transfer mechanism is conditioned for operation and all of the racks in numerical orders above the racks of lowest order are positioned one space above the respective bars l8. Furthermore, in the construction disclosed in the present invention, the arm 20 is not capable of supporting the lowest order adding rack in a position above that shown in Figure 1, as is the case in my before-mentioned application.

Referring to Fig. 1, a cradle, hereinafter designated the subtracting cradle, and comprising spaced

arms

38 and 39 rigidly connected for joint movement by a bail (not shown), is journalled on a shaft 40 extending parallel to the shaft 23 between the group of type bars H and the subtracting racks 14. The arm 38 of the subtracting cradle is substantially in the plane of, and similar to, the arm 20 of the adding cradle, and its lower end is provided with a laterally extending pin 41 effective to contact the forward end 42 of a slot defined by the body of the slide 29 and its upwardly and rearwardly turned portion 32. The arm 39 of the subtracting cradle is substantially in the plane of, and similar to, the arm 2I- of the adding cradle and its lower end operatively supports a dog similar in all respects to the dog 24 of the arm 2|.

It will be understood that the dog of the arm 39 functions to engage the bar l9 identified with the subtracting racks, in the same manner as does the dog 24 with respect to the bar 18 on the adding side of the machine, and that yieldable means similar to spring 25 may be employed to retain the former part in normal position in engagement with its bar [8. A coiled spring 43, acting between the upper end of arm 39 and a pin fixed in the frame of the machine at a point rearwardly of the arm, tends to rock the subtracting bail in a clockwise direction as viewed in Fig. 1. Hence, when either one of the lugs on the pinion 28 of highest order, is caused to pass through -zero in a subtracting operation, the dog on the arm 39 will be disengaged from its bar l8, to permit spring 43 to rock the cradle as previously described, thus moving the pin 4| of arm 38 forwardly, or to the left as is shown in Fig. l, to force the slide 29 in a corresponding direction.

Like the arm 20 of the adding cradle, the arm 38' of the subtracting cradle is devoid of the property of supporting the lowest order subtracting rack so that a fugitive one is not introduced into the pinion of lowest order when the subtracting cradle is rocked as heretofore described.

It will be observed that the slide 29 is invariably moved in a forward direction when the totalizer pinion of highest order is caused to pass through zero in a negative or subtractive operation, whereas a rearward movement is communicated to the slide in every instance in which the totalizer pinion of highest order is caused to pass through zero in a positive or adding movement. Of course, it will be further understood that if the slide already occupies either its forward or rearward positions, as a consequence of the totalizer having passed from a positive to a negative condition, or vice versa, that a subsequent passage of the totalizer through zero in the same direction as occasioned the before-mentioned movement will have no effect. For example, if the totalizer is in a positive condition as a result of the accumulation of additive amounts, and subtractive items are thereafter entered in the machine in excess of the positive total, the slide 29 will be caused to move to its forward position, but if the totalizer is once again caused to pass through zero by the continued accumulation of subtractive amounts in excess of its capacity, the tripping of the dog of highest order and consequent rocking of the subtractive cradle will have no consequential effect because the slide 29 will already be in its forward position.

The movement of the slide 29 is utilized to effect a correct algebraic total. In Figs. 1, 2 and 3, a lever 44 is shown to be pivoted in the machine frame at 45. The free or forward end of the lever 44 is provided with a pin 46 which is slidably received in an angularly disposed cam slot 41 formed in the upper portion 32 of the slide 29. The upper edge of lever 44 is turned laterally to define a shoulder 48 which occupies a position in a plane to the right of the plane of the pinion 49 of lowest numerical order. be obvious that when the slide 29 is moved rearwardly or to the right in Fig. 1, as is the case when the totalizer pinion of highest order is caused to pass through zero in an adding operation, the pin 46 of lever 44 will ride upwardly in the cam slot 41, thus elevating the shoulder 43. On the other hand, when the slide 29 is moved forwardly, or to the left in Fig. 1, the pin 46 in lever 44 will be caused to move downwardly in cam slot 41, thus lowering the shoulder 48.

The pinion of lowest order is supported upon the central step 50, Fig. '7, of a three-stepped guide bushing 5|, which, in turn, is carried on the totalizer shaft l9.

An irregularly shaped plate 52, Figs. 2 and 5, formed with a pair of

opposed lugs

52a and 52b, arranged to align with diametrically opposed pairs of teeth on the pinion of lowest order, is journalled on a bearing step 53 of the bushing 5| in side by side relation with respect to the pinion 49 as shown in Fig. 5.

The plate 52 is fitted with diametrically opposed shouldered pins 54, (Fig. 4) which project through similar circular apertures 55, in the pinion 49. The shoulders 54a of the pins 54 are of such It Will l diameter, with respect to the diameter of the apertures as will permit of one step of relative movement between the plate 52 and pinion 49. More particularly, the relation of the diameter of the shoulders 54a to the diameter of the apertures 55, is such that when the plate 52 is moved with respect to the pinion, its

lugs

52a and 52b,-

will be caused to assume positions in alignment with the next adjacent teeth of the pinion.

Plate 52 is normally urged in one direction of movement with respect to pinion 49 to maintain its respective lugs in the relative positions shown in Fig. 4, by means of a pair of similar springs 51 which act between opposed points on the plate and suitable pins fixed to the adjacent side face of the pinion.

The pins 54 project through and beyond the pinion 49, to provide pivotal supports for a pair of similar arms 58 which are maintained in side by side relationship with respect to the pinion.

Referring particularly to Fig. 5, it will be observed that the pinion 49 of lowest order, together with the plate 52 and arms 58, constitute a unit which is maintained in operative relationship by

flanges

56 and 59 on bushing 5|, which, in turn, is supported on the totalizer shaft l9.

Reverting again to Figs. 4 and 6, the free ends of arms 58 are guided for movement radially of the axis of the totalizer shaft l9 by laterally extending guide pins 60, arranged to be slidably received in similar radially extending slots 6|, formed in the body of the pinion 49 intermediate adjacent teeth. As clearly shown in the figures above referred to, the action of springs 51' tends to maintain the free ends of arms 58 in their outermost positions.

When the totalizer pinion of lowest order and its associated plate and arms are assembled on the totalizer shaft, the arms occupy a position in the plane of the laterally turned shoulder 48 of lever 44, so that. movement of the latter part from the position shown in Figure 4, to that shown in Figure 6, will function to contact the nose 62 of either arm which happens to be in the position shown in Figure 6. Such action of the shoulder 48 on either one of the arms 58, will serve to rotate the plate 52, and hence, its integrally formed

lugs

52a and 52b, in a counterclockwise direction as viewed in Figure 6, into alignment with the next adjacent teeth of the pinion.

Recalling now that the lever 44 is never moved to the position shown in Figure 6, except as a consequence of the passage of the pinion of highest order from a positive to a negative condition, the following description of the accumulation and totaling of subtractive, or negative, amounts will be clear:

Assuming that the pinions of the totalizer have been cleared in engagement with the adding racks in the last preceding totaling operation, and that the highest order pinion has subsequently been caused to pass through zero as a result of the entry of subtractive amounts, the following action will characterize the total taking operation which is made for the purpose of clearing the pinions of that subtractive amount.

The transfer dogs will be restored to their normal position in the first cycle of operation of the machine, one such dog being shown in dotted outline in Fig. 6, which illustrates a totalling operation on the subtracting side of the machine.

In the next cycle of operations, the pinions will be automatically moved into mesh with the subtracting racks. (by means such as are fully disclosed in my beforementioned Patent No. 2,088,982) whereupon the latter parts will rise differential distances dependent upon the extent to which the lug of any particular pinion has been removed from its zero position, that is, the number of tooth spaces which any particular lug has been moved below, and away from, its particular transfer dog. The units rack, however, while imparting the clockwise rotation to pinion 49 causes the nose 62 of one of the arms 58 to bear against the under side of shoulder 48 as the pinion near its 0 position. Continued rotation of pinion 49 causes a lowering of the nose 62 with a consequent counter-clockwise movement of plate 52 in relation to pinion 49 to the extent of one tooth as above mentioned. This of course, permits the pinion 49 to rotate an additional step clockwise, under the power of the units rack l4, to permit the latter to rise the required extra step to show the correct overdraft amount.

In this manner the correct algebraic result is obtained, notwithstanding the fact that the lowest order pinion has not been advanced for the purpose of introducing a fugitive one.

In the event the totalizer is used for the continued accumulation of subtractive amounts, subsequent to passage of the highest order wheel from a positive to a negative condition, it may happen that a transfer will become necessary from the units to the tens order pinion as is the case when either one of the lugs 52a or 5222 con tact the tens order pawl in the course of the accumulation of subtractive amounts. By way of example let us consider that the machine is in the position shown in Fig. 6, where a negative total has just been taken and the totalizer left at 0. It will be remembered that with the parts in this position all the transfer lugs (including 52a. or 52b for the units order) rest in the 0 positions for the negative side of the totalizer, in which position they lie adjacent the under side of the transfer pawls. If the number 8 be now subtracted, the lowering of rack l4 will be accompanied by a counterclockwise rotation of pinion 49 and plate 52, the plate 52, however, moving only 1 step during the time the pinion 49 moves its first two. This is due to the fact that as the pinion 49 rotates, the nose 62 is allowed to move radially away from the shaft l9, allowing the spring 5! to rotate the plate 52 clockwise in relation to the pinion 49. Since the extent of such relative rotation is one tooth space, and since the nose moves its full extent during the rotation of the pinion through its first 2 steps (approximately), the plate 52 receives a resultant counter-clockwise movement of 1 step. We therefore find that after the pinion finishes its 8 steps of movement, the plate 52 has advanced only '7.

Let us now consider that the lug 52b, diametrically opposite lug 52a has likewise advanced 7 steps counter-clockwise from the position in which it is shown in Fig. 6, so that it lies only three steps from the position of lug 52a. in this figure. We must likewise consider that the nose 62 of the lower arm 58 in Fig. 6 has advanced 8 steps and was moved radially away from shaft l9 (coincidentally with the nose 62 of the upper arm 58).

Now let us subtract 2 more from the units wheel. This should bring the nose 82 of the lower arm 58 in exactly the position of the nose 62 on the upper arm in Fig. 6, and should also cause the lug 52b to move into the position of 52a in this figure to cause a tripping of the tens transfer pawl. When the subtraction rack I4 is lowered these two increments, the nose 82 on the lower arm 58 strikes the under side of the shoulder 48 and is thereby cammed radially toward the shaft l9. This radial movement causes a counter-clockwise movement of the plate 52 relative to the pinion 49 to the extent of 1 tooth space, with the result that the plate 52 receives its required 3 steps of counter-clockwise rotation while the pinion receives its 2. As above mentioned this causes the transfer pawl of the tens order to be tripped and the lug 52b to lie in the subtractive position assumed by lug 52a in Fig. 6. Should a negative total be now taken, it would read 10, which is correct.

To illustrate the manner in which the fugitive unit is entered when the totalizer is returned to its positive side, let us again assume that the parts are in the position shown in Fig. 6 where a negative total has just been taken. A lowering of the adding rack I3 (Fig. 4) to put a positive balance of 1 unit in the totalizer would lower the lug 52b one step and cause a transitional carry with the accompanying raising of the shoulder 48. The raising of the shoulder 48 allows the springs 51 to contract and move the nose 62 away from shaft l9, together with a clockwise rotation of lug 52?) an additional step. This places lug 52b 2 steps below its position in Fig. 6, or 1 step below its additive 0 position shown in Fig. 4. If a total be now taken, the

lug 521) will return 1 step counter-clockwise to its additive 0 position to show 1 as the accumulated total which is correct.

Considering now an operation where the totalizer is in a positive condition and amounts are added until its capacity is exceeded, and the similar instance where the totalizer is in a negative condition and amounts are subtracted until its capacity is exceeded, it is evident that no additional correction-is necessary in these cases. The mechanism operates correctly in such cases due to the fact that the corrective movement of plate 52 is never more than one step in one direction. The shoulder 48 can be lowered or raised only one step, so that before two corrective steps may be given in any one direction, the totalizer must be returned through zero to its opposite state.

To show the operation of the machine in another unusual condition,

However, since the units, tens and hundreds wheels stood at "0 on the adding side and at 9 on the subtracting side (in the position shown in Figure 4), the transitional carry which took place during the subtraction operation lowered flange 48, which in turn lowered the upper arm 58 (Figure 4) and thereby rotated tooth 52a from the position as shown in Figure 4 to that shown in Figure 6. This caused the transfer pawl in the units order to be tripped, and since the totalizer wheels in the tens and hundreds orders stood at "9, on the subtraction side, caused them also to trip their transfer pawls to add a unit to the thousands order. This advanced the thousands pinion from "0 to 1, producing the correct amount of 111,000.

If a total should now be taken this amount of 111,000 would be printed.

Let us now assume that 333,000 is added. Remembering that the units wheel is in the position shown in Figure 6 and the tens and hundreds wheels are in the position where their lugs lie similarly to

lugs

52a and 52b in Figure 6, the totalizer is shifted to engage the adding racks I3. We now have the units, tens and hundreds wheels in the 9 position on the adding side, and the other wheels in their proper complementary positions,

The entire totalizer reading, on the adding side, as follows 999,888,999

The addition of 333,000 causes the wheels to rotate And show 000,221,999

on the adding side.

Since this addition caused a transitional carry, flange 48 was raised, allowing springs 51 to rotate arms 58 and

teeth

52a and 52b one step clockwise from the position shown in Figure 6 to that shown in Figure 4. This tripped the units transfer tooth, and since the tens and hundreds' wheels were in their 9 positions, caused them also to transfer to the thousands order, leaving the wheels at the end of the operation in the following position: 000,222,000, which is the correct amount.

In the above example the tripping of the transfer pawl in the highest order to move flange 48 did not advance the units order wheel the corresponding step, but since the effect was the same in this particular example, the illustrative numerals in this example show the units order, for the sake of clarity, as though the pinion had been advanced.

The totalizer wheels are all held against rotary movement by an aliner shown at I95 in Figures 15 and 17 of the Sundstrand Patent No. 1,965,611, referred to in this specification. This aliner is engaged with the teeth of the totalizer wheels just before they are disengaged from one set of racks, and is disengaged from the teeth of the wheels just after they are engaged with the other set of racks. This prevents rotation of the units wheel by the springs 51 when it is not engaged with the actuating racks I3I4.

It will be seen that I have provided a simple and economically manufactured means of producing a correct algebraic total in adding and subtracting machines of the type disclosed.

I claim as my invention:

1. A totalizer comprising in combination, a registering element of lowest numerical order, a rack arranged to rotate said element in one direction to effect addition, a second rack arranged to rotate said element in a reverse direction to effect subtraction, a lug supported for movement concentrically of the axis of said element, means providing a driving connection between said element and said lug, said connection being arranged to permit one step of independent movement of said lug with respect to said element, means operable to produce a single step of movement of said lug relative to said element as an incident to a total taking operation to establish a relationship identified with negative amounts, a registering element of highest numerical order, addition and subtraction racks arranged to rotate said highest order element, a part movable into and out of position to actuate said single step means and means automatically actuated as an incident to passage of the totalizer through zero to move said part.

2. Computing mechanism comprising in combination, a set of adding racks, a set of subtracting racks, a set of pinions adapted to be optionally operated by said sets of racks, a lug arranged to rotate with the pinion of highest order, a lug arranged to rotate with, and relative to, the pinion of lowest order, a part operable as an incident to a total taking operation to effect relative movement between the lug and pinion of lowest order, means actuated by the lug on said wheel of highest order to render said part ineffective when the wheel of highest order is caused to pass from a negative to a positive condition as a result of an operation in engagement with the adding racks, and means actuated by the lug on said wheel of highest order to render said part operable when the wheel of highest order is caused to pass from a positive to a negative condition as a result of an operation in engagement with the subtracting racks.

3. Computing mechanism comprising in combination, a plurality of sets of racks, a set of pinions adapted to be optionally operated by said sets of racks, a lug arranged to rotate with the pinion of highest order, a lug arranged to rotate with, and relative to, the pinion of lowest order, a part operable as an incident to a total taking operation to effect relative movement between the lug and pinion of lowest order, means actuated by the lug on said wheel of highest order to render said part ineifective when the wheel of highest order is caused to pass from a negative to a positive condition as a result of an operation in engagement with one of said sets of racks, and means actuated by the lug on said wheel of highest order to render said part operable when the wheel of highest order is caused to pass from a positive to a negative condition, as a result of an operation in engagement with another of said sets of racks.

4. Computing mechanism comprising in combination, a set of adding racks, a set of subtracting racks, a set of pinions adapted to be optionally operated by said sets of racks, a lug arranged to rotate with the pinion of highest order, a lug arranged to rotate with, and relative to, the pinion of lowest order, a part operable as an incident to a total-taking operation to effect relative movement between the lug and pinion of lowest order to move said last mentioned lug in a direction relatively reverse to the direction of movement of the pinion in a total-taking operation, to thereby permit an additional step of movement of the rack of lowest order in such total-taking operation, and means actuated by the lug on the wheel of highest order to render said part operable or not operable when the wheel of highest order is caused to pass through zero.

5. Computing mechanism comprising in combination, jointly operable sets of adding and subtracting racks, a set of pinions adapted to be optionally operated by said sets of racks, a lug arranged to rotate with the pinion of highest order, a lug arranged to rotate with, and relative to, the pinion of lowest order, a part movable into and out of a position to effect relative movement between the lug and pinion of lowest order to move said lug in a direction relatively reverse to the direction of movement of the pinion in a total-taking operation, to thereby permit an additional step of movement of the rack of lowest order in such totaltaking operation, and

means actuated by the lug on the wheel of highest order in conjunction with either of said sets of racks to actuate said part.

6. Computing mechanism comprising in combination, a set of adding racks, a set of subtracting racks, a set of pinions adapted to be optionally operated by said sets of racks, a lug arranged to rotate with, and relative to, the pinion of lowest order, a part operable as an incident to a total-taking operation to effect relative movement between the lug and pinion of lowest order, to move said last mentioned lug in a direction relatively reverse to the direction of movement of its pinion in a total taking operation so as to permit an additional step of movement of the rack of lowest order in such total taking operation, and means controlled by the wheel of highest order to render said part operable when the wheel of highest order is caused to pass from a positive to a negative condition and to disable said part when the wheel of highest order is moved from a negative to a positive condition.

7. Computing mechanism comprising two sets of racks, a set of pinions adapted to be optionally operated by said sets of racks, a lug arranged to rotate with and relative to, the pinion of lowest order, and means controlled by said pinion of highest order to effect relative movement between the lug and pinion of lowest order as an incident to a total taking operation.

8. A totalizer comprising a set of pinions arranged to be rotated in one direction to add and in the opposite direction to subtract, each of said pinions having 20 teeth, two diametrically o posite lugs to define positive and negative zero positions of the pinion of highest order, two diametrically opposite lugs arranged to revolve with, and relative to, the pinion of lowest order and to define positive and negative zero positions thereof, means to produce relative movement between the pinion and lugs of lowest order and means actuated as an incident to a passage of the pinion of highest order through zero to condition said last mentioned means to produce relative movement between the pinion and lugs of lowest order as an incident to a total taking operation.

9. A totalizer comprising actuating racks, a set of pinions arranged to be rotated by the racks, a lug arranged to revolve with the pinion of highest order, a lug arranged to revolve with and relative to, the pinion of lowest order and means controlled by the lug on said pinion of highest order to effect relative movement between the pinion and lug of lowest order to permit an extra step of movement of the rack of lowestorder as an incident to a total taking operation.

10. Computing mechanism comprising actuating racks, a set of pinions arranged to be rotated by the racks, a lug arranged to rotate with, and relative to, the pinion of lowest order, a lug con nected to rotate with the pinion of highest order; and means controlled by the lug on the pinion of highest order to effect relative movement between the pinion and lug of lowest order as an incident to a total taking operation.

11. A totalizer comprising a set of pinions ar ranged to be rotated in one direction to add and in the opposite direction to subtract, each of said pinions having twenty teeth, two diametrically opposite lugs arranged to revolve with the pinion of highest order, two diametrically opposite lugs arranged to revolve with, and relative to, the pinion of lowest order, and means arranged to be controlled by the lugs on said wheel of highest order to eflect relative movement between the lugs and pinion of lowest order to cause an algebraic addition of one as an incident to a total taking operation.

12. Computing mechanism comprising two sets of racks, a set of pinions identified with the two sets of racks and operable optionally thereby to accumulate numbers, either additively or subtractively, and to present the true algebraic sum thereof as a consequence of a total taking operation, not withstanding the said sum may alternately be of a positive or negative character, automatic means whereby the subtracting rack in lowest denominational order will be moved a distance representing one unit in excess of the amount represented on the pinion of lowest order as an incident to a total taking operation, and means controlled by the pinion of highest order to condition said last mentioned means for op eration.

13. Computing mechanism comprising in combination, a set of adding racks, a set of sub tracting racks, a set of pinions adapted to be optionally operated by said sets of racks in the accumulation of positive and negative amounts, lugs on said pinions eflective to control the extent of movement of said racks in total taking operations, and means actuated as an incident to a movement of the pinion of highest order from a positive to a negative condition to enable the subtracting rack of lowest order to move one step farther than the lugs on the lowest order pinion during a total taking operation.

14. A computing machine comprising in combination, a set of adding racks, a set of subtracting racks, a set 01' pinions adapted to be optionally operated by said sets of racks for the accumulation of positive and negative amounts, transfer mechanism associated with each of said sets of racks, lugs on said pinions to actuate said transfer mechanisms in one direction of rotation, to produce a carry of one from any given pinion to the pinion of next higher numerical order and to abut said transfer mechanism in a second direction of rotation to arrest relative movement between said pinions and racks to define the zero positions of the former, and means controlled by the lugs on the pinion of highest order to produce a step of movement of one of the racks of lowest order in excess of the movement normally permitted by the normal position of the lug on the pinion of lowest order.

15. A computing mechanism including an adding and subtracting totalizer having a plurality of pinions, actuating elements therefor, and means, operable when the totalizer is overdrafted, to control movement of the actuating element in the lowest denominational order, so that it will move, during a total taking operation, a distance representing one unit in excess of the amount represented on the pinion of lowest order.

16. A computing mechanism including a totalizer having a plurality of pinions, means operating with the pinions for arresting them during total taking operations, and means, effective when the totalizer is overdrafted, for causing relative movement between the pinion of lowest order and its arresting means during total taking operations.

OSCAR J. SUNDS'I'RAND.