US3212708A

US3212708A - Digital input manually operable toy computer

Info

Publication number: US3212708A
Application number: US346282A
Authority: US
Inventors: Nutting William; Stubbmann Albert
Original assignee: Kohner Bros Inc
Current assignee: Kohner Bros Inc
Priority date: 1964-02-20
Filing date: 1964-02-20
Publication date: 1965-10-19
Anticipated expiration: 1982-10-19

Description

Oct. 19, 1965 w. NUTTING ETAL 3,212,703

DIGITAL INPUT MANUALLY OPEHABLE TOY COMPUTER 3 Sheets-Sheet 1 Filed Feb. 20, 1964 INVENTORS ML L/AM NOW/Y6- |o8 BY 4455/97- SrUBBMANM Ti @5150 4A Arvzwgys ML, ML c Oct. 19, 1965 w. NUTTING ETAL 3,212,703

DIGITAL INPUT MANUALLY OPERABLE TOY COMPUTER 3 Sheets-Sheet 2 Filed Feb. 20, 1964 INVENTORS u 6 6m ow W Wm WM 4 A Mi, Mi

Oct. 19, 1965 w. NUTTING ETAL 3,212,708

DIGITAL INPUT MANUALLY OPERABLE TOY COMPUTER Filed Feb. 20, 1964 3 Sheets-Sheet 3 lNVENTOR-S h/u/AM Nun-MG BY 415 597 STUBBMA WY dim, ma

United States Patent C) 3,212,708 DIGITAL INPUT MANUALLY @PERAIBLE TGY CGMPUTER William Nutting and Albert Stubbrnann, New York, N.Y.,

assignors to Kohner Bros, Inc, New York, N.Y., a corporation of New York Filed Feb. 20, 1964, Ser. No. 346,282 9 Claims. (Cl. 2351l14) This invention relates to a digital input manually operable toy computer.

It is an object of our invention to provide a highly simplified, rugged and durable computer of the character described.

It is another object of our invention to provide a toy computer of the character described which is arranged to receive a singularly simplified form of input, to wit, a units input, as distinguished from the more complex input normally fed into manually operable computers, that is to say, inputs which include figures composed of units, tens, hundreds, etc. values.

It is another object of our invention to provide a toy computer of the character described which is capable of performing both adding and subtracting operations and which is so constructed that when set for adding it is unable to perform subtraction and, contrariwise, when set for subtraction is unable to perform addition.

It is another object of our invention to provide a toy computer of the character described with which a child cannot complete a subtraction operation employing figures that would yield a negative (less than zero) result which would be meaningless and confusing to a child.

It is another object of our invention to provide a toy computer of the character described with an inexpensive arrangement for insuring correct indexing of the output figures.

It is another object of our invention to provide a toy computer of the character described which is so designed as to prevent unintentional overshooting of output figures having values greater than units, that is to say, of output figures representing tens values.

It is another object of our invention to provide a toy computer of the character described in which the input member and the parts of the computing mechanism are so arranged that the tens and unit figures of the output are disposed alongside of one another and in immediate mutual lateral juxtaposition, so that they may be easily read out as a single number and so that thereby a child of tender years can come to recognize succession of numbers as they progress from units to numbers short of one hundred, and so that such a child can further be led easily into the recognition of addition and subtraction processes.

It is another object of our invention to provide a toy computer of the character described which when set for addition or subtraction furnishes different appropriate and easy-to-follow instruction symbols for a child to heed in order to insure proper direction of rotation of the digital input means.

It is another object of our invention to provide a toy computer of the character described which is easy for a child to handle and use, but which, nevertheless, is so constructed that it is not readily susceptible to breakage, regardless of the mishandling to which it may be put.

Other objects of our invention in part will be obvious and in part will be pointed out hereinafter.

Our invention accordingly consists in the features of construction, combinations of elements, and arrangement of parts which will be exemplified in the device hereinafter described and of which the scope of application will be indicated in the appended claims.

In the accompanying drawings in which is shown one of the various possible embodiments of our invention,

3,212,798 Patented Get. 19, 1965 FIG. 1 is a plan view of a toy computer embodying our invention;

FIG. 2 is an enlarged rear View of the computer with the back panel removed;

FIG. 3 is a fragmentary front view of the computer, the same illustrating the digital input scale set for a subtraction operation, and in this manner differing from the digital input scale shown in FIG. 1 which is set for an addition operation;

FIG. 4- is a fragmentary rear view of the computer, the same illustrating the check pawls set for a subtraction operation and thus contrasting with the positions of the check pawls in FIG. 2 which are set for an addition operation;

FIGS. 5 and 6 are enlarged sectional views taken substantially along the lines 5-5 and 6-6, respectively, of FIG. 1;

FIG. 7 is an enlarged rear perspective view of the parts of the computing mechanism;

FIG. 8 is a rear perspective view of the driving and driven parts of the units and tens rotors near the terminal phase of their driving engagement; and

FIG. 9 is an enlarged sectional vieW taken substantially along the line 9--9 of FIG. 2 and illustrating the arrangement employed to prevent completion of a subtraction operation that would yield a negative result.

Referring now in detail to the drawings, the reference numeral 10 denotes a toy computer constructed in accordance with our invention. The external shell of the computer constitutes a shallow casing 12 having an open rear end which is closed by a back panel 14. The front face 16 of the casing is generally fiat, with certain exceptions to be noted hereinafter, and is bounded at its periphery by a short rearwardly extending flange 18 which terminates in a ledge defining a rearwardly facing seat 20 that snugly receives the back panel 14. The plan configuration of the front face can be of any desired shape and here is illustrated in the form of a triangle with rounded sides 22 and rounded apices 24. The configuration roughly matches the over-all plan configuration of the computing mechanism (see FIG. 2) and, therefore, in addition to being of pleasant appearance, has the virtue of providing a compact arrangement. The casing is manufactured from a sturdy plastic material which can be subjected to abuse without fear of breakage. For example, a suitable material is a high impact (butadienemodified) polystyrene. Satisfactory results are obtained Where the other working parts of the computing mechanism are made of the same material, except for the gong, the springs, the back panel and the numeral-carrying discs hereinafter described.

The principal parts of the computing mechanism are: a finger manipulatable digit input wheel 26, this being in elusive of the elements functionally integral therewith; a units rotor 28; and a tens rotor 30. The digit input wheel 26 has a continuous two-way driving engagement in a one-to-one ratio with the units rotor and the units rotor has an intermittent two-way driving engagement in a ten-to-one ratio with the tens rotor 39.

The digit input wheel includes a flat disc 32 formed with ten round openings 34, arranged in a circle, set in slightly from the periphery of the disc. The openings are uniformly spaced apart, so that their center-to-center angular relationship is 36. Each opening is of about the right size to admit the tip of a childs finger which usually will be the index finger of the dominant hand. The center of the disc is provided with a through bore 36 (see FIG. 5) in which there is force-fitted an enlarged section of a shaft 38. Said shaft is provided with a head that butts against the outer surface of the disc 32. The reduced diameter of the shaft 38 is rotatably journalled in an opening it) in a large diameter shallow boss 41 in the front wall of the casing 12. The lower tip of the shaft, as soon will be seen, is held a fixed distance behind the boss, so that the digit input wheel is mounted externally of the casing and adjacent the front wall thereof in such a fashion that it can experience rotary, but not axial, movement.

The lower tip of said shaft 38 is force-fitted in a central opening of a gear 42 located inside the casing and held in spaced relationship from the inner surface of the boss 41 by a circular rib 44- in one piece with the casing. The upper face of the gear is in rotary sliding engagement 'with the lower surface of this rib. It will be understood,

of course, that when the digit input wheel is rotated, it turns the gear with it. Ten pins 46, arranged in a ring concentrically about the shaft 38, integrally project from the back surface of the gear. These pins, like the openings 34, are equiangularly spaced apart.

Means is provided to act as an input scale to assist in turning the digit input wheel through any selected measured whole number of angular increments that are equal to the center-to-center angular spacings of the openings 34. Said input scale means supplies two separate input scales, to wit, an addition scale and a subtraction scale, which are selectively implacable in operable position wherein the scale figures can be viewed. When either scale is in such operable position the other scale preferably is concealed. In order to appreciate the functioning of the input scale means it should be pointed out here that we provide in association with the digit input wheel a finger stop 48 that is carried by the front face of the casing and overhangs a marginal peripheral portion of the disc 32. Specifically, the stop overhangs the marginal portion of the disc in which the openings 34 are located. The stop functions in the same manner as the stop used in conjunction with the finger manipulatable wheel of a dial telephone. The stop is of a width that fills the space between two adjacent openings 34. Hence, when a child turns the input wheel 26 with his finger in any selected opening 34, rotation of the wheel will be halted when his finger strikes the stop.

The input scale means above referred to includes ten reading apertures 50 in the opaque top wall of the casing 12 and arranged in a circle around the axis of rotation of the disc 32. The apertures are so placed that a different aperture is in radial alignment with each different opening 34 at such time as the stop 48 is located between two such openings. The reading apertures 50 function to permit viewing therethrough of either of two shiftable input scales located beneath the same, one scale being an addition input scale, and the other scale being a subtraction input scale. Both scales are suitably imprinted or otherwise marked on a fiat annulus 52 situated directly beneath the front wall of the casing and snugly rotatable on the back surface of the boss 41. The central opening of the annulus is journalled on the circular rib 44. Arranged circularly around the annulus is a first set of numbers 54- (shown in solid lines in FIG. 1) which constitute the addition input scale, and also arranged circularly around the annulus is a second set of numbers 56 which constitute the subtraction input scale. Both sets of

input numbers

54, 56 are located at a common radius that renders them capable of being viewed through the reading apertures 59. The numbers of each input set are spaced 36 apart from numbers of the same set and the numbers of each input set are alternated with and spaced 18 from the bracketing pair of numbers of the other input set. Thereby the annulus 52 can be angularly arranged to show all the numbers of either input set through the reading apertures 50, and then by turning the annulus 18 in an appropriate direction all the numbers of the other input set will be shown through said apertures. The opaque portions of the boss 41 conceal the set of input numbers not in registration with the apertures 50 at any given time.

The addition set of input numbers 54 (see FIG. 1) is arranged with its zero symbol (0) adjacent and to one side of the stop 48 when its numbers are visible through the reading apertures 50. The numbers of said set are arranged in an ascending order (0, 1, 2, etc.) in a direction opposite to that in which the input wheel 26 is turned (in PEG. 1 shown as clockwise) for addition. The subtraction set of input numbers 56 (see FIG. 3) is arranged with its zero symbol (0) adjacent and to the other side of the stop 4-3 when its numbers are visible through the reading apertures 50 (the annulus 52 having been turned 18 clockwise as viewed in FIG. 1 from the addition position). The numbers of the subtraction input set are arranged in ascending order (0,1, 2, etc.) in a direction opposite to that in which the input wheel 26 is turned (in FIG. 3 shown as counterclockwise) for subtraction.

Manually manipulatable means is included to shift the annulus 52 18 between its addition and subtraction positions. Said means comprises a radial finger 58 integral with the annulus and projecting outwardly therefrom through a notch 641 formed in the shallow side wall of the boss 41 so that the tip of the finger is exposed above the front surface of the casing. The side walls of the notch selectively abut opposite one or the other of the side edges of the finger to define the addition and subtraction positions. A ledge 62 protruding forwardly from the front wall of the casing and terminating short of the side walls of the notch by spaces sli htly in excess of the width of the finger prevents the annulus from accidently drifting away from addition or subtraction position after being set therein. The finger is sufiiciently flexible to be deliberately forced over the ledge, as by raising the finger, when the position of the annulus is to be changed intentionally The units rotor 28 comprises a units gear 64 in the plane of and in mesh with the input gear 42. Both gears have an equal number of teeth and are of like diameter so that the input gear 42 which i turned by the input wheel 26 drives the units gear in a one-to-one ratio. Said units gear 64 is suitably mounted for rotation in back of the front wall of the casing and to this end includes a forwardly extending integral central hollow hub (knob) 66 the base of which is journalled in a bearing hole in the front wall of the casing. The hub has an undercut shoulder 68 slightly in front of the casing which receives a split ring 70 that captively holds the gear in place on the casing and yet permits it to turn.

A cardboard disc 72 interposed between the back face of the casing and the front face of the units gear 64- is perforated at a few spots to tightly receive nibs '74 so that said disc and the gear 64 are functionally integral. The disc has imprinted on its front face a series of equiangularly spaced circularly arranged units output numbers 76. Since there are ten such units output numbers, their mutual spacing is 36. The units numbers can be seen one at a time through an output aperture '73 in the front wall of the casing. The order of the units output number 76 is such that successively higher of said numbers appear in the aperture 78 when the input wheel 26 is turned in an adding direction (clockwise as viewed in FIG. 1). The positions of the units output numbers 76 on the disc 72 are synchronized with the positions of the finger openings 34 whereby when the disc 32 is so angularly disposed that the finger stop 48 is midway between two adjacent openings 3 preferably the width of the finger stop is substantially equal to the distance between any two adjacent openings 34, a single units output number will be midway between the top and bottom edges of the output aperture 78. Said output aperture is large enough to fully expose a single units number situated therein midway between the top and bottom edge of the aperture. Said top and bottom edges subtend an are on the disc 72 not exceeding 36 in order that when a single unit number is centered in the output aperture the preceding and following numbers can not be seen.

The tens rotor 30 comprises a circular plate 80 formed with ten equiangularly spaced radially outwardly extending rearwardly offset teeth 82 having a center-to-center spacing of 36. These teeth are of sufficiently large radius to be successively engaged by a spur 84 projecting rearwardly from the back surface of the gear 64 adjacent the periphery thereof. The angular length of the spur is less than the angular distance between any two teeth 82 so that the spur 84 can, once each revolution, enter into driving engagement with a tooth 82. The spur will advance the tooth 36 during such driving engagement and then will disengage itself from the tooth.

Thus, in effect, the spur 84- constitutes a mutilated gear that engages the gear formed by the teeth 82 once for every revolution of the units rotor 28 and will, once for every rotation of the units rotor, turn the tens rotor 30 through of a revolution. Driving engagements of this type are well known in the computer art and will not be further detailed herein. However, attention is called to the fact that the tips of the teeth 82 are radially spaced from the center of the plate 80 a distance substantially in excess of the radial distance from the spur 84 to the center of the units rotor 28. This arrangement is advantageous in that a low angular speed is imparted to the tens rotor so that there is less tendency for such rotor to continue turning by virtue of its inertia when the spur be comes disengaged from a tooth 82. Thus the tens output rotor is to such extent restrained from providing a false output reading. At a later point of the specification a specific means will be described which further and substantially restrains accidental or unwanted rotation.

It will also be observed that each tooth 82 flares outwardly towards its tip thereby to reduce the space between the teeth at their tips. This has the further advantage that if, for any reason, the rotation of the tens rotor is accelerated to a rotary speed greater than the rotary speed of the units rotor While the two rotors are in a driving phase the following tooth 82 will strike the trailing edge of the spur 84 and thereby slow down rotation of the tens rotor. This particular operation may take place upon occasion when the means later to be described for restraining accidental or unwanted rotation of the tens rotor speeds up the tens rotor during one phase of its operation.

A cardboard disc 86 interposed between the back face of the casing and the front face of the circular plate 30 is perforated at a few spots to tightly receive nibs so that the plate 80 and the disc 86 are functionally integral The disc 86 has imprinted on its front face a series or equiangularly spaced circularly arranged tens output numbers 90. Since there are ten such tens output numbers, their spacing is 36. The tens output numbers can be seen one at a time through the output aperture '78. The order of the tens output numbers is such that successively higher of said numbers appear in the aperture 73 when the units rotor is turned in an adding direction (counterclockwise as viewed in FIG. 1) during a period of engagement between the spur 8 and a tooth 82. The pOSltlOnS of the tens output numbers on the disc 36 are synchromzed with the positions of the units output numbers '76 on the disc 72 so that after the spur $4 has completed a driving engagement with a tooth 82 only a single tens number will be visible through the aperture 78;. p

The peripheries of the two output discs 72, 8d are juxtaposition beneath the output aperture 78 and the units numbers and tens numbers are so oriented on their respective discs that the two numbers (one of each set) P P ing in the aperture at any one time are 1n mutual lateral juxtaposition and thereby can be jointly read as a single output figure including both a tens number and -a un t-s number. For this purpose the tens numbers and units numbers are so situated on their respective discs that the numbers appearing in the output aperture have their bases located proximate to the bottom edge of the aperture and their tops proximate to the top edge of the aperture.

Preferably, the centers of rotation of the units rotor, the tens rotor and the digit input Wheel are located on the .apices of an isosceles triangle with the two equal sides of the triangle constituting the center-to-cen-ter distances between the centers of rotation of the input wheel and the units rotor and of the input wheel :and the tens rotor. Even more desirably, the aforesaid triangle is equilateral.

The circular plate is suitably mounted for rotation in back of the front wall of the casing in the same manner as the units gear 64. Thus said plate includes a forwardly extending integral central hollow hub (knob) 92 the base of which is journalled in a bearing hole in the front wall of the casing. The hub 92 has an undercut shoulder 94 slightly in front of the casing which receives a split ring 96 that captively holds the plate in place on the casing and yet permits it to rotate when one of its teeth 82 is engaged by the spur 84.

As a child-pleasing concomitant to the operation of the toy computer It), We may provide a sound generating means which will issue a single sound for each unit input added or subtracted in operation although, lflS will be appreciated from the following description, the sounds may run so closely together as to blend in with one another. The aforesaid means constitutes a metal gong 98 secured within the casing 12. A stationary shaft 100 extends re-arw'ardly rrom the front wall of the easing and passes through an opening in the rounded apex of the gong. The tip of the shaft is mutilated to enlarge the same and form a head which presses against the interior of the gong. A metal clapper 1&2 is afiixed to a free end of a resilient wire 104 having a central portion turned around a stationary shaft 106 integral with the casing. The other end of the wire is anchored to a second stationary shaft 108 likewise integral with the casing. The clapper-carrying portion of the wire passes alongside of and is shaped so as to be biased into engagement with the ring of pins 46 on the input Wheel 26. Additionally, the clapper-carrying portion of the wire is formed with a hump 110 that extends inwardly towards the ring of pins. The hump is of V-shaped configuration and the wide portion of the hump is approximately equal to the space between any pair of pins.

It now will be appreciated that when the input Wheel 26 is rotated the pins 46 will move in succession past the hump 1M and as each pin goes past the hump it will swing the clap-per against the gong, the height of the hump bemg approximately equal to the distance between the gong and clapper in the idle position of the clapper.

Moreover, the hump is so positioned that it lies between a pair of pins when a units output number 7 6 is exposed through the output aperture '78 and when an opening 34 is adjacent the finger stop 48. This insures proper registration of the units numbers With the output aperture since if perchance a child when operating the computer fails to bring his finger against the stop 48, the hump will cam the closest pin into a position wherein a units number is centered in the output aperture.

The indexing action of the hump 110 is not particularly strong since the wire 14M is light and since the hump is located in a cantilever portion of the wire. However a strong indexing action is not considered to be necessary inasmuch as in normal operation of the computer a child will not remove his finger from the opening in the input wheel until his finger has struck the stop 48.

A more positive indexing means is provided for the tens rotor to insure that a tens number will be centered in the output aperture. This is desirable if, for example, the spur should be moving so fast at the time it engages a tooth that the circular plate will tend to overshoot, i.e. pass its desired 36 increment. it should also be noted at this point that the indexing means already described for the units wheel, i.e. the hump 110, and the indexing means now to be described for the tens rot-or serve the additional function of holding the units rotor and tens rotor in any position to which they have been moved by operation of the computer. That is to say, neither one of these rotors will after a computation tend to drift away from their computed output positions. The aforesaid indexing means and holding means for the tens rotor is, as shown herein, in the form of a resilient wire 112 having its opposite ends anchored on stationary shafts 114. The wire passes alongside of the bases 116 of the teeth 32 and is shaped so as to be biased into engagement there-with. The wire 112 is formed with a V-shaped thump 1118 extending toward the ring of tooth bases 116. The width of the base of the hump is approximately equal to the space between any pair of tooth bases 116. It will be appreciated that the hump when between a pair of adjacent tooth bases 116 will inhibit notation of the .tens rot-or unless the tens rotor is positively turned by the spur 84. Also, if the tens rotor should be turned through any angle which fails to leave the tip of the hump midway between a pair of adjacent tooth bases 116, the camming action of the hump will automatically turn the tens rotor to a position in which one of the tens numbers 90 will be centered in the output aperture '78 since the hump 118 is so positioned that it lies centered between a pair of bases 116 when a tens output number is centrally exposed in the output aperture.

As the tens rotor 30 is turned through an arc of 36 each time a tooth 82 is engaged by the spur 84 (as the units number exposed in the output aperture 78 changes from 9 to in an adding direction or from 0 to 9 in a subtracting direction) the hump 118 will be raised. But since the ends of the wire 112 are fixed, the hump will be partially flattened and elongated. Therefore the hump will resiliently press strongly against the base 116 then passing beneath it. This creates a force which indexes the position of the tens rotor. That is to say, after the base 116 has passed below the tip of the hump, the sloped trailing side of the hump will cam against said base and supply an additional force tending to turn the tens rotor in the same direction as it is being turned by the spur 84-. If this force turns the tens rotor too rapidly while the spur is still in a driving cycle, the next succeding tooth 82 will strike the trailing edge of the spur 84 and thus prevent overshooting of the tens rotor. Moreover, the tens rotor will come to rest with the hump 118 centered between adjacent bases 116 at which time a tens output number is centered in the output aperture 78.

It will be apparent that the two humps 11%, 118 will hold the units rotor 28 and the tens rotor 3t respectively, in any position to which they have been turned, at which time a single one of each of their respective output numbers will be centered in the output aperture and that these rotors thereby will be prevented from accidentally driftmg.

From the description up to this point, the operation of the computer is easy to follow. Assume that some number is exposed through the output aperture, say the num ber 23 as illustrated in FIG. 1. Now if a child wishes to add a number to the said output number he simply sets (or leaves the setting of) the finger SS in ADD position, places his finger in that input opening aligned with the exposed addition number 54 to be added and turns the input disc 32 in a clockwise direction until his finger strikes the stop 48. Let it be supposed that the number to be added is 8. The child places his finger in the input opening 34 radially aligned with the number 8 of the addition input scale 54 which is exposed through an aperture 50.

It will be observed that the child cannot add any more than a unit number (one to nine) in any single operation. It also should be pointed out that with the numbers above given (twenty-three plus eight), as the input disc 32 is turned, the units output numbers 76 will progress in an ascending order without affecting the position of the tens rotor and tens output number until the number 9 is reached. Then as the units output numbers move from 9 to 0 the spur 554 will engage a tooth 82 so as to turn the tens rotor 36 and thus change the tens output number from 2 to 3. This will take place in the example under discussion between the sixth and seventh angular input increment of rotation of the input disc 32.

If additional numbers are to be added the child will dial the same into the computer with the finger 58 set in ADD position.

if it is desired to subtract a number the finger 58 is shifted to SUB position and the child will proceed as in addition except that now he must rotate the input disc in a counterclockwise direction and he will now be using the subtraction input numbers 56 which will be seen through the apertures 50 in the subtraction setting of the finger 58. It will be apparent that the tens output number will shift to a one lower figure each time the units output numbers move from O to 9.

Inasmuch as it is contemplated that the computer may be used by children of various ages, even very young children who may be unable to quickly associate the direction the input disc is turned with an addition or subtraction operation and who therefore might become confused because they happened to use the addition scale while turning the input disc in a subtraction direction, and vice versa, pursuant to a feature of the invention, means is included when the computer is in an addition posture to permit the input disc only to turn in an addiiton direction. The aforesaid rotation restraining means functions in a similar manner for subtraction. That is to say, when the machine is in a subtraction posture it will permit the input disc only to be turned in a subtraction direction.

The rotation restraining means comprises a pair of

check pawls

120, 122, the first of these, i.e. the pawl 120, being an addition check pawl and the second, i.e. the pawl 122, being a subtraction check pawl. Both of the pawls are oscillatably mounted on a shaft 124 integral with the casing 12 and located near the input gear 42. The rear end of the shaft 124 protrudes beyond the rearmost check pawl 12% and has turned about it a hair spring 126, the opposite ends of which bear against protuberances 1225 on the check pawls. Thereby the tips of the two pawls are urged toward the periphery of the gear 42. The check pawls diverge from the mounting shaft 124 in a manner such that the addition check pawl extends in the general direction of rotation of the input gear 42 for addition and the subtraction check pawl 122 extends in the general direction of rotation of the input gear 42 for subtraction. The free end of each pawl is shaped in the form of a tooth which extends approximately radially inwardly toward the center of rotation of the input gear.

The fiat annulus 52 from which the finger 58 protrudes also is provided with a radial lug 132 having an upturned tip 134. This tip is located in the angle defined by the sides of the two check pawls that face the input gear 42. One side of the lug tip engages and lifts the subtraction check pawl (as shown in FIG. 2) when the finger 58 is in ADD position. The other side of the lug tip engages and lifts the addition pawl 120 (as shown in FIG. 4) when the finger 58 is in SUB position.

With the addition pawl operative (as shown in FIG. 2, i.e. with the subtraction pawl lifted to inoperable position), the input gear 42 only can turn in an addition direction. As it turns in such direction, the teeth of the gear 42 will successively carn out the tip 13%) of the addition pawl (against the restoring force of the spring 126) which thereby permits such rotation of the input gear 42 and a corresponding addition rotation of the input disc 32. However if it is attempted to rotate the input disc in a subtraction direction and to correspondingly rotate the input gear 42, the tip of the addition check pawl will block such movement. The subtraction check pawl functions in a similar fashion when operable so as to allow only subtraction rotation of the input disc 32 and of the input gear 42. Accordingly when the computer is set for addition the child only can turn the input disc in an addition direction and when the computer is set for subtraction a child can only turn the input disc in a subtraction direction.

It is desirable to provide symbols for the child to follow so that he will be encouraged to initially turn the input disc in a correct direction which corresponds to the setting, i.e. posture, of the computer. Thereby he will be prone to operate the computer correctly in the first instance and should not have to try an incorrect direction of rotation in order to ascertain the correct direction. The indicating symbols are in the form of directional arrows 136, 138 which are imprinted on the upper face of the fiat annulus 52. There is at least one directional arrow 136 for addition and at least one directional arrow 138 for subtraction. In the illustrated embodiment of the invention two directional arrows of each type are employed. The front wall of the boss 41 is formed with at least one opening 140 through which a directional arrow 136 or 138 can be viewed. As shown herein the directional arrows and the openings 14% are so located that they can be seen through one or more of the input openings 34.

The addition directional arrows 136 are aligned with the openings 140 when the setting finger 58 is in addition position and the subtraction directional arrows 138 are aligned with the openings 14% when the setting finger 58 is in subtraction position. To this end the directional arrows associated with any given opening 146 are spaced apart 18 center-to-center. Obviously the addition directional arrows indicate a clockwise direction of rotation which is the addition direction of rotation of the input disc 32 and the subtraction directional arrows indicate a counterclockwise direction of rotation.

It will be observed that the computer of the present invention is a very simple, that is to say, almost basic arithmetic computer. It only will take a units input. In other words, in any single operation no more than nine units can be added or subtracted. It does not accept a tens input except as the same may constitute a series of units inputs. Moreover its maximum output capacity is 99; thereafter it recycles back to start a fresh series of output numbers beginning at O and progressing in an ascending order. This simplicity of input and output numbers is conducive to training a child in basic concepts of arithmetical subtraction and addition. It is considered unnecessary for such training for the computer to include hundreds figures or greater and, hence, these have been deliberately omitted. By the time a child when performing addition operations has reached output numbers in the high 90s he should fully comprehend the nature of an addition operation and therefore will not be confused when the output number progresses beyond 99 to start a fresh series.

The foregoing does not hold true of subtraction operations the resultant of which is less than 0. For instance if the output number should be 3 and a child intends to subtract from it a number in excess of 3, the resultant output number would read in the 90s. This is due to the fact that the resultant is negative and the computer has no other way of indicating a negative result. A negative result is meaningless to a young child and therefore pursuant to an additional feature of the present invention the computer 1d includes means to prevent the completion of a subtraction operation which would yield a negative result.

The aforesaid means which is shown in FIG. 9 is or" a particularly simple nature and comprises a pair of cooperating

abutments

142, 144. One of the abutments, e.g. the abutment 142, protrudes from the inner face of the top wall of the casing 12. The other abutment, in this instance the abutment 144, protrudes from the upper face or" the circular plate at this being a part of the tens rotor 30. One of the abutments, e.g. the abutment ltd-2, is formed with a sloping side 146 and a square side 148. The sloping side 146 is so oriented that it will be engaged by the moving abutment 1144 once each 360 of rotation of the tens rotor as the tens rotor turns in an addition direction. Hence, as the tens rotor turns in such direction the abutment 144 will ride over the sloping side 1% of the abutment 142 and the two abutments will not impede the addition operation of the computer. However when the computer is operated in a subtraction di rection and when the abutment 144 strikes the square side 14? of the abutment 142 the input disc 32 can not be further turned in such a subtraction direction. The two abutments are so located that the abutment 144 will strike the square side of the abutment 142 when the tens rotor is starting to turn from the position in which the 0 tens output numeral is exposed through the viewing aperture '78 to the position in which the 9 tens output numeral is exposed through the viewing aperture. Thus operation of computer in subtraction direction is blocked when the tens rotor tries to turn from 0 output to 9 output. It will be observed that at this time the spur 84 is in engagement with a tooth 82 so that the units rotor will also be blocked.

it it is desired to reset the machine back to 0 for both rotors, the child simply has to spin the rotors in an adding direction by means of the knobs 66, 92.

It thus will be seen that we have provided a device which achieves the several objects of our invention and which is well adapted to meet the conditions of practical use.

As various possible embodiments might be made of the above invention, and as various changes might be made in the embodiment set forth, it is to be understood that all matter herein described or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

Having thus described the invention, there is claimed as new and desired to be secured by Letters Patent:

1. A toy computer comprising a casing having an output aperture, a train consisting of three members rotatably mounted for bidirectional movement in an addition direction and a subtraction direction on said casing, the first member of the train constituting a finger manipulatable di it input wheel disposed externally of the casing and an input gear functionally integral with the wheel and disposed internally of the casing, the input wheel having ten equiangularly spaced finger input openings, the second member of the train constituting a units rotor disposed internally of the casing, said units rotor including a digits gear in continuous two-way driving engagement in a one-to-one ratio with the input gear, said units rotor further including a spur, the last member of the train constituting a tens rotor disposed internally of the casing and having teeth in intermittent two-way driving engagement in a ten-to-one ratio with the spur in such a manner that once each revolution of the units rotor, and for an arc of movement of one-tenth of a revolution of the units rotor, the spur will engage a tooth on the tens rotor to turn the tens rotor through one-tenth of a revolution, said units rotor and said tens rotor bearing a set of ten difierent units numbers and a set of ten different tens numbers respectively in equiangularly spaced arrangement thereon and in positions for the numbers of each set to be viewed singly through the output aperture in mutual lateral juxtaposition so as to be read out of the output aperture as a single number composed of a single tens number followed by a single units number, means for selecting between the addition or subtraction directions of the digit input Wheel either one or the other direction at any one time, two circular sets of equiangularly spaced numerically successive digits, each of said sets ascending in an opposed angular direction, means selectively exposing either one or the other set and blocking the unselected set from view as a direct function of the selected direction of rotation, and a finger stop associated with the digit input wheel and cooperable with an operators finger in an input aperture to stop rotation of the input wheel in both the addition direction and the subtraction direction when said operators finger strikes the finger stop.

2. A toy computer comprising a casing having an output aperture, a train consisting of three members rotatably mounted for bidirectional movement in an addition direction and a subtraction direction on said casing, the first member of the train constituting a finger manipulatable digit input wheel disposed externally of the casing and an input gear functionally integral with the wheel and disposed internally of the casing, the input wheel having ten equiangularly spaced finger input openings, the second member of the train constituting 21 units rotor disposed internally of the casing, said units rotor including a digits gear in continuous two-way driving engagement in a one-to-one ratio with the input gear, said units rotor further including a spur, the last member of the train constituting a tens rotor disposed internally of the casing and having teeth in intermittent two-way driving engagement in a ten-to-one ratio With the spur in such a manner that once each revolution of the units rotor, and for an arc of movement of one-tenth of a revolution of the units rotor, the spur will engage a tooth on the tens rotor to turn the tens rotor through one-tenth of a revolution, said units rotor and said tens rotor bearing a set of ten different units numbers and a set of ten different tens numbers respectively in equiangularly spaced arrangement thereon and in positions for the numbers of each set to be viewed singly through the output aperture in mutual lateral juxtaposition so as to be read out of the output aperture as a single number composed of a single tens number followed by a single units number, an input scale constituting a scale member mounted within the casing to oscillate between two extreme positions, a first set of ten equiangularly spaced different addition scale numbers on said scale member, a second alternately interposed set of ten equiangularly spaced different subtraction scale numbers on said scale member and means providing input openings on the casing through which in the two extreme positions of the scale member either the addition set of scale numbers or the subtraction set of scale numbers are selectively viewable around the digit input wheel while the other set of scale numbers is concealed, and a finger stop associated with the digit input wheel and cooperable with an operators finger in an input aperture to stop rotation of the input wheel in both the addition direction or the subtraction direction when said operators finger strikes the finger stop.

3. A toy computer as set forth in claim 2 wherein the casing includes a shallow outwardly protuberant boss over which the digit input wheel is rotatable, wherein the oscillatable scale member is located directly under the boss and wherein the input openings are disposed in the boss, said boss having a notch at the side thereof and said oscillatable scale member having a finger extending through said notch for manual oscillation of the scale member, said casing including means to limit oscillation of said scale member to said two extreme positions.

4. A toy computer as set forth in claim 3 wherein the means for limiting oscillation of the scale member constitutes the ends of the notch and wherein the casing further includes means for releasably retaining the finger and the scale member in either selected one of the two extreme positions against accidental displacement thereof.

5. A toy computer comprising a casing, a train including plural members rotatably mounted on said casing, the first member of the train constituting a finger manipulatable digit input wheel disposed externally of the casing, at least one member of the train constituting a units rotor, at least another member of the train constituting a tens numbered rotor, said members being arranged in mutual driving relationship so that one rotation of the input wheel produces one rotation of the units rotor and so that once each revolution of the units rotor, and for an arc of one-tenth of a revolution of the units rotor, the units rotor will turn the tens rotor through one-tenth of a revolution, an output aperture in the casing through which the numbers on the rotors can be read out, means providing input openings on the scale around the input wheel, a scale member mounted within the casing to oscillate between two extreme positions, a first set of ten equiangularly spaced difierent addition scale numbers on said scale member, a second alternately interposed set of ten equiangularly spaced different subtraction scale numbers on said scale member, one set of numbers being visible through the input openings in one extreme position of the scale member and the other set of numbers being visible through the input openings in the other extreme position of the scale member, opposite direction of rotation symbols on the scale member, and apertures on the casing through which a symbol of one direction of rotation or the other is exposed while the other direction of rotation symbol is concealed, the direction of rotation symbols and the addition and subtraction scale numbers being so mutually related that when the addition scale numbers are visible through the input openings the direction of rotation symbol for addition rotation of the input wheel is exposed through the symbol aperture and when the subtraction scale numbers are visible through the input openings the direction of rotation symbol for subtraction rotation of the input wheel is exposed through the symbol aperture.

6. A toy computer comprising a casing, a train including plural members rotatably mounted on said casing, the first member of the train constituting a finger manipulatable digit input wheel disposed externally of the casing, at least one member of the train constituting a units rotor, at least another member of the train constituting a tens numbered rotor, said members being arranged in mutual driving relationship so that one rotation of the input wheel produces one rotation of the units rotor and so that once each revolution of the units rotor, and for an arc of one-tenth of a revolution of the units rotor, the units rotor will turn the tens rotor through onetenth of a revolution, an output aperture in the casing through which the numbers on the rotors can be read out, means providing input openings on the scale around the input wheel, a scale member mounted within the casing to oscillate between two extreme positions, a first set of ten equiangularly spaced different addition scale numbers on said scale member, a second alternately interposed set of ten equiangularly spaced different subtraction scale numbers on said scale member, one set of numbers being visible through the input openings in one extreme position of the scale member and the other set of numbers being visible through the input openings in the other extreme position of the scale member and means to permit unidirectional rotation of the input wheel only in an addition direction when the addition scale numbers are visible through the input openings and to permit unidirectional rotation of the input wheel only in a subtraction direction when the subtraction scale numbers are visible through the input opening.

7. A toy computer as set forth in claim 6 wherein the means to permit opposite unidirectional rotations of the input wheel includes a pair of oppositely oriented addition and subtraction check pawls, an input gear rotatable with the input wheel and cooperating with said pawls and a cancelling member movable by the oscillatable scale member to cancel the operation of the subtraction pawl when addition numbers are visible through the input openings and to cancel the operation of the addition pawl when subtraction numbers are visible through the input openings.

8. A toy computer comprising a casing, a train including plural members rotatably mounted for bidirectional movement in an addition direction and a subtraction direction on said casing, the first member of the train constituting a finger manipulatable digit input wheel disposed externally of the casing, at least one member of the train constituting a units numbered rotor, at least another member of the train constituting a tens numbered rotor, said members being arranged in mutual driving relationship so that one rotation of the input wheel produces one rotation of the units rotor and so that once each revolution of the units rotor, and for an arc of onetenth of a revolution of the units rotor, the units rotor will turn the tens rotor through one-tenth of a revolution, an output aperture in the casing through which the numbers on the rotors can be read out, an input scale of ten equiangularly spaced different numbers around the digit input wheel, and means blocking rotation of the tens numbered rotor in a subtraction direction only beyond a certain predetermined point beyond which the tens numbered rotor cannot move from a position in which the 0" number on said tens numbered rotor is exposed through the output aperture to a position in which the 9 number on said tens numbered rotor is exposed through the output aperture.

9. A toy computer comprising a casing, a train including plural members rotatably mounted for bidirectional movement in an addition direction and a subtraction direction on said casing, the first member of the train constituting a finger manipulatable digit input wheel disposed externally of the casing, at least one member of the train constituting a units numbered rotor, at least another member of the train constituting a tens numbered rotor, said members being arranged in mutual driving relationship so that one rotation of the input wheel produces one rotation of the units rotor and so that once each revolution of the units rotor, and for an arc of onetenth of a revolution of the units rotor, the units rotor will turn the tens rotor through one-tenth of a revolution, an output aperture in the casing through which the numbers on the rotors can be read out, an input scale of ten equiangularly spaced difierent numbers around the digit input wheel, and means blocking rotation of the tens numbered rotor in a subtraction direction only beyond a certain predetermined point beyond which the tens num bered rotor cannot move from a position in which the 0 number on said tens numbered rotor is exposed through the output aperture to a position in which the 9 number on said tens numbered rotor is exposed through the output aperture, said means comprising a stationary abutment member on the casing and an abutment member carried by the tens numbered rotor, the casing abutment member being disposed in the path of travel of the rotor carried abutment member, the side of one of the abutment members which engages the other abutment member when the tens numbered rotor is turned in an addition direction of rotation being sloped so that said abutment members will not prevent rotation of the tens numbered rotor in an addition direction of rotation, the other side of said one abutment member being square so that when this side is abutted by the other abutment member upon rotation of the tens numbered rotor in a subtraction direction such rotation of the tens numbered rotor will be checked, said abutment members being located to check rotation of the tens numbered rotor in a subtraction direction between the two stated positions of said rotor.

References Cited by the Examiner UNITED STATES PATENTS 2,166,081 7/39 Thompson 23574 2,797,047 6/57 Lehre 235-74 FOREIGN PATENTS 1,107,851 1/56 France.

187,572 3/22 Great Britain. 571,167 12/57 Italy.

62,168 7/ 12 Switzerland.

LEO SMILOW, Primary Examiner.

Claims

5. A TOY COMPUTER COMPRISING A CASING, A TRAIN INCLUDING PLURAL MEMBERS ROTATABLY MOUNTED ON SAID CASING, THE FIRST MEMBER OF THE TRAIN CONSTITUTING A FINGER MANIPULATABLE DIGIT INPUT WHEEL DISPOSED EXTERNALLY OF THE CASING, AT LEAST ONE MEMBER OF THE TRAIN CONSTITUTING ROTOR, AT LEAST ANOTHER MEMBER OF THE TRAIN CONSITUTING A TENS NUMBERED ROTOR, SAID MEMBERS BEING ARRANGED IN MUTUAL DRIVING RELATIONSHIP SO THAT ONE ROTATION OF THE INPUT WHEEL PRODUCES ONE ROTATION OF THE UNITS ROTOR AND SO THAT ONCE EACH REVOLUTION OF THE UNITS ROTOR, AND FOR AN ARC OF ONE-TENTH A REVOLUTION OF THE UNITS ROTOR, THE UNITS ROTOR WILL TURN THE TENS ROTOR THROUGH ONE-TENTH OF A REVOLUTION, AN OUTPUT APERTURE IN THE CASING THROUGH WHICHT THE NUMBERS ON THE ROTORS CAN BE READ OUT, MEANS PROVIDING INPUT OPENINGS ON THE SCALE AROUND THE INPUT WHEEL, A SCALE MEMBER MOUNTED WITHIN THE CASING TO OSCILLATE BETWEEN TWO EXTREME POSITIONS, A FIRST SET OF TEN EQUIANGULARLY SPACED DIFFERENT ADDITION SCALE NUMBERS ON SAID SCALE MEMBER, A SECOND ALTERNATELY INTERPOSED SET OF TEN EQUIANGULARLY SPACED DIFFERENT SUBTRACTION SCALE NUMBERS ON SAID SCALE MEMBER, ONE SET OF NUMBERS BEING VISIBLE THROUGH THE INPUT OPENINGS IN ONE EXTREME POSITION OF THE SCALE MEMBER AND THE OTHER SET OF NUMBERS BEING VISIBLE THROUGH THE INPUT OPENINGS IN THE OTHER EXTREME POSITION OF THE SCALE MEMBER, OPPOSITE DIRECTION OF ROTATION SYMBOLS ON THE SCALE MEMBER, AND APERTURES ON THE CASING THROUGH WHICH A SYMBOL OF THE ONE DIRECTION OF ROTATION OR THE OTHER IS EXPOSED WHILE THE OTHER DIRECTION OF ROTATION SYMBOL IS CONCEALED, THE DIRECTION OF ROTATION SYMBOLS AND THE ADDITION AND SUBTRACTION SCALE NUMBERS BEING SO MUTUALLY RELATED THAT WHEN THE ADDITION SCALE NUMBERS ARE VISIBLE THROUGH THE INPUT OPENINGS THE DIRECTION OF ROTATION SYMBOL FOR ADDITION ROTATION OF THE INPUT WHEEL IS EXPOSED THROUGH THE SYMBOL APERTURE AND WHEN THE SUBTRACTION SCALE NUMBERS ARE VISIBLE THROUGH THE INPUT OPENINGS THE DIRECTION OF ROTATION SYMBOL FOR SUBSTRACTION ROTATION OF THE INPUT WHEEL IS EXPOSED THROUGH THE SYMBOL APERTURE.