US3652826A

US3652826A - Binary entry apparatus for a calculating machine

Info

Publication number: US3652826A
Application number: US1627A
Authority: US
Inventors: Rene Chekroun; Jean-Claude Ragot
Original assignee: Burroughs Corp
Current assignee: Unisys Corp
Priority date: 1969-05-30
Filing date: 1970-01-09
Publication date: 1972-03-28
Anticipated expiration: 1989-03-28
Also published as: GB1273102A; FR2061838A5

Abstract

Decimal values are entered in a selector carriage of a calculating machine by means of a driving shaft, a plurality of friction clutches, and the controlled activation of a driven shaft and a gear wheel associated therewith. Control of the driven shaft and its associated gear wheel is provided by means of a plurality of slides responsive to key depression, four of said slides being separately activatable in the entry of decimal values 1, 2, 4 and 8 and activatable in selected combinations in the entry of values 3, 5, 7 and 9. A fifth slide provides for the controlled activation of a gear wheel associated with the driving shaft each time a key is depressed, to thereby effectuate a one unit translation of the selector carriage preparatory to the entry of the next lower order digit of the amount being entered.

Description

United States Patent Chekroun et al.

[451 Mar. 28, 1972 [72] inventors: Rene Cheltroun, Montrouge; Jean-Claude Ragot, Sevran, both of France [73] Assignee: Burroughs Corporation, Detroit, Mich.

[221 Filed; Jan. 9, 1970 21] Appl. No.: 1,627

[30] Foreign Application Priority Data Dec. I9, 1969 France ..69l7808 [56] Relerences Cited UNITED STATES PATENTS 2,837,274 6/1958 Godel ..235/58P Dilks et al ..235/6l PG X Gorner et al..o Maples .235/61 PG Primary ExaminerStephen J. Tomsky Attorneyl(enneth L. Miller and Edwin Wv Uren s7 1 ABSTRACT Decimal values are entered in a selector carriage of a calculating machine by means of a driving shaft, a plurality of friction clutches, and the controlled activation of a driven shaft and a gear wheel associated therewith. Control of the driven shaft and its associated gear wheel is provided by means of a plurality of slides responsive to key depression, four of said slides being separately activatable in the entry of decimal values 1, 2, 4 and 8 and activatable in selected combinations in the entry of values 3, S, 7 and 9. A fifth slide provides for the controlled activation of a gear wheel associated with the driving shaft each time a key is depressed, to thereby effectuate a one unit translation of the selector carriage preparatory to the entry of the next lower order digit of the amount being entered.

29 Claims, 18 Drawing Figures PATENTED m 2 a 1912 SHEET 01 0F 12 Q. m & m m mm m Mm. E cJv V E m mm RJ AGENT.

\\\\ \\\\\\\\\\\\\\\\N\\\\NN\\\\\\ \\N\\\N\NNNN\N\N\NNNN\\\\\\\\\\\N PATENTE D MR 2 8 1912 IH FI CZUF 12 PATENTEU MAR 28 I972 SHEEF 05 0F 12 PATENTED m 28 m2 SHEET [37 0F 12 PATENTEU MAR 28 I972 SHEET CEQF 12 PhTENTEnmza 1972 EHKET US 72 BINARY ENTRY APPARATUS FOR A CALCULATING MACHINE BACKGROUND OF THE INVENTION Calculating machines are generally provided with various well-known entry means which are suitable for entering decimal amounts indexed in a keyboard, but which are not readily adaptable for receiving binary information which may be transmitted from data processing equipment were it desired to couple a calculating machine thereto for the purpose of converting and printing such information in decimal form.

The use of a separate add rack or sector for entering decimal amount in each order of ten in known calculators renders such calculators incompatible with data processing equipment involving digital computers particularly from the standpoint of the nature of the information that may be handled thereby. Conventional calculators are accordingly not readily adaptable for receiving and converting binary information, as by the employment of solenoid means and the like as a substitute for the keyboard thereof.

SUMMARY OF THE INVENTION It is accordingly an object of the present invention to provide a printing calculator having a keyboard and entry means suitable for entering decimal amounts, the entry means being readily adaptable or convertible for receiving binary information independently of the keyboard should it be desired to couple the calculator to data processing equipment for converting and printing binary information in decimal form.

An important aspect of the invention is the use of a rotating shaft and means associated therewith for entering digit values ranging from one through nine in the ordinally arranged toothed members of a selector carriage, such associated means comprising a driven cam shaft, a pair of friction clutches, and a gear wheel associated with the cam shaft. Selected cams of the cam shaft are separately operable for activating the gear wheel for varying intervals of time sufficient to advance the individual toothed members of the selector carriage a l, 2, 4 and 8 tooth distance, and operable in combination for activating the gear wheel for varying intervals of time sufficient to advance the members a 3, 5, 7 and 9 tooth distance.

Another aspect of the invention is the use of means associated with a different selected cam of the cam shaft for translating the selector carriage to the left each time a listing key of the keyboard is depressed, such means comprising a third friction clutch, a gear wheel associated with the rotating shaft, and a gear train and grooved shaft cooperating translatably with the frame of the selector carriage.

Still another aspect of the invention is the use of a plurality of keyboard slides and a plurality of transverse levers which are responsive to the depression of the listing keys of the keyboard, for activating the cam shaft, the friction clutches, and the gear wheels associated with the cam shaft and with the rotating shaft for differentially advancing each toothed member of the selector carriage and for translating the carriage to the left preparatory to the entry of a digit value in the next lower order toothed member.

A further aspect of the invention is the use of pivotal lever means associated with the various cams of the cam shaft and with the keyboard slides to controllably activate the friction clutches, such lever means comprising a plurality of cam follower levers operably responsive to the cams of the cam shaft and a plurality of pivotally connected sensing arms blockably associated with the keyboard slides, the blocking of the sensing arms by the keyboard slides being effective to activate the friction clutches to effectuate the rotation of the cam shaft and the gear wheels associated with the cam shaft and with the rotating shaft.

BRIEF DESCRIPTION OF THE DRAWINGS These and other objects, aspects and advantages of the invention will be more clearly understood from the following description when read in conjunction with the accompanying drawings, in which:

FIG. I is a schematic sectional elevation of a calculating machine in which the preferred embodiment of the invention is incorporated and in which representative components thereof are shown in relationship with the various operating sections of such calculator;

FIG. 2 is a top plan view of the keyboard of the embodiment showing the listing keys in relationship with their associated transverse levers;

FIG. 3 is a bottom plan view of the keyboard showing the transverse levers in relationship with the longitudinal slides, such slides being disposed in a cutout formed in the underside of the keyboard;

FIG. 4 is a front sectional elevation of the keyboard showing the longitudinal slides and the transverse lever associated with the 1 key, said lever appearing in non-activated relationship with its associated slide;

FIG. 5 is a front sectional elevation of the keyboard showing the transverse lever of FIG. 4 in activated relationship with its associated slide;

FIG. 6 is a sectional view of the keyboard taken along the line 66 of FIG. 4 showing one of the keyboard slides in its home position relative to the transverse levers;

FIG. 7 is a sectional view of the keyboard showing the slide of FIG. 6 in its translatably activated position relative to the transverse levers;

FIG. 8 is a sectional view of the keyboard taken along the line 8-8 of FIG. 4 showing one of the slides in its home position and in inactivated relationship with the transverse levers and its associated sensing arm;

FIG. 9 is a sectional view of the keyboard showing the slide of FIG. 8 in activated relationship with the transverse levers and in a translatably activated position relative to its associated sensing arm;

FIGS. 10A and 10B present a left and right portion, respectively, of a perspective view of the entry apparatus taken from the left front corner, the two portions when mutually orientated by means of a coordinating line appearing in each portion showing the selector carriage of the embodiment and means responsive to the keyboard effective for entering digit values therein, and showing also means for translating the selector carriage preparatory to the entry of the next lower order digit;

FIG. ll is a sectional view taken along the line ll-ll of FIG. 10A showing various details of the entry apparatus;

FIG. 12 is a perspective view of the cams and cam shaft of the invention in relationship with an associated friction clutch and driving shaft;

FIG. 13 is an exploded view of the friction clutch by means of which the toothed members of the selector carriage are advanced;

FIG. 14 is an exploded view of the friction clutch by means of which the selector carriage is translatably activated preparatory to the entry of the next lower order digit;

FIG. 15 is a sectional view taken along the line [5-15 of FIG. 10B showing the friction clutch controllably associated with the differential advancement of the toothed members of the selector carriage and showing also release means associated with such clutch;

FIG. 16 is a sectional view taken along the line l6-l6 of FIG. IDA showing the friction clutch controllably associated with the translation of the selector carriage and showing also release means associated therewith; and

FIG. 17 is a perspective view of the selector carriage of the embodiment taken from the right front corner and showing various support and control details thereof.

DETAILED DESCRIPTION OF THE INVENTION The preferred embodiment of the invention comprises a "IO-key keyboard 51 as shown in FIG. 2, and a translatable selector carriage 21 as shown in FIGS. 10B and 17. Means are provided for differentially advancing the toothed members and for translating the selector carriage in opposing directions. The selector carriage is comprised of a plurality of toothed members 23 and a plurality of intermediate gear wheels 25 (FIG. 17). The toothed members 23 are each comprised of an arcuate webbed portion bearing the numbers through 9, and of teeth disposed along the periphery thereof opposite the webbed number-bearing portion. The invention is adapted for use in a printing calculator of the type schematically illustrated in FIG. 1, wherein amounts re gistered in the selector carriage are entered into the calculating machine and selectively transferred to various operating sections by means of a plurality of twelve pitch receiving pinions 27 (also shown in FIGS. IIIA and I7) and a plurality of 45-pitch rotary transfer wheels 29. The intermediate gear wheels 25 and the toothed members 23 are securely arranged relative to one another by means of connected frame members 31 and 33 (FIG. 108).

A single pinion 35 shown in FIGS. 1 and 10B is maintained in cooperating relationship with a gear wheel 37, and is individually cooperably with the intermediate gear wheels 25 as the carriage is translated to the left in step-by-step fashion during the entry of the individual digit values constituting an amount to be processed. When all of the digit values of an amount have been registered in the selector carriage 21, the carriage is rotated in a clockwise direction (as viewed in FIG. 1) to thereby engage the intermediate gear wheels 25 with the receiving pinions 27. During the ensuing cycling of the calculating machine, the rotary transfer wheels 29 are advanced a nine tooth distance in a clockwise direction to thereby zeroize the toothed members 23. Means for rockably engaging the selector carriage 21 with the receiving pinions 27, and for advancing the rotary transfer wheels 29 in a clockwise direction, are not germane to the present invention and are accordingly omitted from this disclosure.

Other pinions and gear wheels shown in FIG. I may be identified in order to more clearly define the type of calculator to which the present invention is adapted. The pinion 39 is representative of a plurality of printing wheels effective for printing amounts on a paper-bearing platen 40. The lO-pitch pinions 41 are representative of a pair of accumulators which receive additive amounts directly from the rotary transfer wheels 29, and subtractive amounts from a plurality of intermediate wheels designated 43. The pinions 45 and 49 and the pin wheels 47 are representative of a calculating section capable of performing shortcut multiplication and division.

The keyboard of the embodiment, as shown in FIGS. 2 and 3, comprises a block 51 having a plurality of transverse grooves 53 (FIGS. 8 and 9) formed in its upper portion, and a pair of

cutouts

55 and 57 formed in its lower portion. A plurality of transverse levers 59 are rockably disposed in the transverse grooves 53 and are rotatably supported by a shaft 61 attached to a pair of rightwardly extending arms of the keyboard block, said levers being also biased in an upward clockwise direction on the shaft 61 by a plurality of springs 63 connected to the leftmost extremities of the levers and to a shaft 65 supported by a pair of leftwardly extending arms of the keyboard block. Each of the transverse levers 59 is pro vided with an upright extension (as best shown in FIGS. 4 and 5) that is fitted snugly into a slot formed in the underside of a corresponding key 67, each key being so attached to at least one of the transverse levers. As shown in FIG. 2, the keys I through 9, 00, and 000 are each connected to a separate single transverse lever 59, and the decimal point and 0 keys are each connected to a separate pair of transverse levers. The motor bar, also shown in FIG. 2, along with other operation control keys and motor bars, are connected to a plurality of separate transverse levers 59' which are pivotally disposed on a shaft 69 also supported by the leftwardly extending arms of the keyboard block. These levers 59' are biased in a counterclockwise direction on the shaft 69 by springs 63' (FIG. 3) connected to a shaft 65' which is also supported by the rightwardly extending arms of the block. The shaft 69, in

cooperation with the inner extremities of vertical slots formed in the transverse levers 59, serves to define the home position of the clockwise-biased transverse levers (as shown in FIGS. 4 and 5). Mechanism associated with the motor bar and with other operation control keys of the printing calculator may be disposed within the cutout 57 (FIG. 3) of the keyboard block, for cycling the calculating machine.

A plurality of longitudinal slides 71A through 710 (FIGS. 3, 4 and 5) are slideably supported within the cutout 55 of the keyboard block by means of a pair of shafts 73 fixed to the side walls of such cutout. the shafts 73 cooperating with a pair of elongated slots formed in each of the slides as shown in FIGS. 6 through 9. These slides 71A through 710 are provided with a series of vertical slots of predetermined size and shape formed in their uppermost portions, the pattern of slot formation and the predetermined angle of the slopes of the slots for each slide determining whether the rockable lowering of a given transverse lever will cammingly contact one of its slopes and thereby translate the slide rearwardly. Each of the slides 71A through 716 is biased forwardly on the shafts 73 (to the right as viewed in FIG. 8) by means not shown in the drawings, and each is translatable rearwardly (to the position shown in FIG. 9) by the camming action of at least one transverse lever against at least one of the slopes formed by the slots of the slide.

The transverse levers 59 have been separately identified in FIGS. 2, 6 and 8, in order to facilitate an identification and explanation of the slides that are translatably activated by the various transverse levers and their associated keys of the keyboard. It can be seen from FIG. 2 that the 0 key is connected to the

levers

59 and 59, the 00 key is connected to the lever 59 the 000 key is connected to the lever 59", the 1 key is connected to the lever 59", the 2 key to the lever 59', the 3 key to the lever 59", the 4 key to the lever 59", the 5 key to the lever 59", the 6 key to the lever 59 the 7 key to the lever 59", the 8 key to the lever 59", and the 9 key to the lever 59. It can be seen also that the decimal key is connected to the transverse levers S9 and 59". Like the 30 motor bar, the decimal point key, although shown in FIG. 2, is neither included nor described in the present disclosure, it not being an essential part of the invention. The pattern of slot for mation of the slide 71A is shown in FIGS. 8 and 9. It can be seen that this slide, which corresponds to a digit value of l, is translatable to the position shown in FIG. 9 by the rockable lowering of the levers 59

S9

59, 59", and 59". The slide 71A is accordingly translatable through the depression of the 3, I, S, 9, and 7 keys of the keyboard respectively. The slide 71B, which corresponds to a digit value of 2, is translatable to a position corresponding to that shown in FIG. 9 by the rockable lowering of the levers 59", 59, 59', and 59". The slide 718 is accordingly translatable through the depression of the 3, 2, 6 and 7 keys of the keyboard respectively. Slide 71C, which corresponds to a digit value of 4, is translatable rearwardly by the rockable lowering of the levers 59", 59", 59" and 59, or by the depression of the 6, 5, 4 and 7 keys respectively. The slide 71D, which corresponds to a digit value of 8, is translatable rearwardly by the depression of the 9 and 8 keys and through the consequent lowering of the levers S9 and 59 Slide 71E is provided with a pattern of slot formation such that the rockable lowering of the

levers

59 and 59, which is to say the depression of the 000 and 00 keys, will translatably activate the slide to a position corresponding to that shown in FIG. 9. Slide 71F is provided with a pattern of slot formation such that the rockable lowering of each of the levers 59 through 59" with the exception of the levers 59 and 59' will cammingly translate the slide to the position of FIG. 9. Slide 71F is accordingly translatably activated by the depression of the 0 and 000 keys, and by the depression of each of the listing keys I through 9.

The longitudinal slides 71A through 71E are each provided with a depending projection 72 as shown in FIGS. 8 and 9, such projection assuming a cleared relationship with its associated sensing arm 74 when the slide is located in its forward home position, and assuming a blocking relationship with said sensing arm (as shown in FIG. 9) when the slide is translated rearwardly by a transverse lever 59. The slide 71G shown in FIGS. 6 and 7 may be identified as a power slide effective for initiating each entry operation. The pattern of slot formation provided this power slide is such that the slide is translated from the position shown in FIG. 6 to the position shown in FIG. 7 each time a transverse lever 59 is rockably lowered by the depression of any one of the listing keys (excluding the decimal point key). Slide 71G is provided with a depending projection 75 and a pivotal arm 77 rotatably connected thereto by means of a stud 81. A hair spring 79 effectively biases the pivotal arm 77 in a clockwise direction on this stud to thereby provide a blocking limit for an upwardly biased sensing member 83 when the slide is located in its forward home position, said pivotal arm 77 and projection 75 permitting entry of the sensing member 83 therebetween when the slide is translated rearwardly to the position shown in FIG, 7.

With reference to FIGS. A and 108, a driving shaft 85 rotatably supported by an exterior frame member of the calculating machine and by a frame member 143 is connected to a motor 87 (illustrated in FIG. 1) by means of a continuous drive belt 89 disposed between a pulley 91 fixed to the shaft 85 and a pulley-carrying shaft of the motor (not shown). The shaft 85 is continuously rotated in a counterclockwise direction (as viewed in FIG. 10A) whenever the motor 87 is maintained in an operating state. Fixed to the driving shaft 85 are a pair of spaced-apart disks 93 (FIG. 14) which are housed within a pair of spaced-apart

friction clutches

95 and 97, the former clutch being shown in the exploded view of FIG. 14 and the latter in an assembled state in FIG. 12. The friction clutch 97 is operably effective to couple a cam shaft 101 to the rightmost disk 93 of the rotating driving shaft 85, as will be explained in detail in a subsequent section. The cam shaft assembly 101 is rotatably supported by

frame member

145 and 147, and, as shown in FIGS. 10A and 12, comprises a cylindrical housing portion 103 within which the friction clutch 97 is disposed, a plurality of cams 105A through 1051 and a fixed disk 107 (FIG. 13) disposed within and forming a part of a third friction clutch 99. The cams 105A through 105D are provided with raised portions which are cooperably effective for advancing the individual toothed members 23 of the selector carriage 21 from one to nine units of rotational travel, and the

cams

105E and 105F are provided with raised portions which are individually effective for translating the selector carriage two and one units of lateral movement, respectively, and cooperably effective for translating the selector carriage three units of lateral movement.

The cams 105A and IOSF are each provided with raised portions which extend one tenth of their circumference (36), the

cams

105B and 105E are each provided with raised portions extending one fifth of their respective circumferences (72), cam 105C has a raised portion extending two fifths of its circumference H44), and cam 105D is provided with a raised portion extending four-fifths of its circumference (288). The raised portions of various of these cams are staggered relative to one another in such manner that the trailing end of the cam 105F coincides with the leading end of the cam 105A, the leading end of the cams 10513 and 105D coincide with one another and also with the trailing end of the cam 105A, the leading end of the cam 105C coincides with the trailing end of the cam 1058, and the trailing end of the cam 105D coincides with the leading end of the cam 105F. The raised portions of the

cams

105E and 105F are also staggered relative to one another in such manner that the trailing end of the cam 105E coincides with the leading end of the cam 1051 As shown in FIGS. 12, 13 and 14, each of the

friction clutches

95, 97, and 99 is comprised of a

disk member

93 or 107 fixed to a rotatable shaft, and a spring member 109 having a pair of outwardly and oppositely directed projections 11] anchorably fixed to a

hub member

113, 115 or 117, and to a

housing member

103, 119 or 121. The hub member 113 ofthe clutch 97 is provided with a single stop 123, and the

hub members

115 and 117 are provided with a plurality of

stops

125 and 127, respectively. The cylindrical housing portion 103 of the cam shaft assembly 101 is provided with a single backup stop 129, and the

housing members

119 and 121 are provided with a plurality of backup stops 131 and 133, and are fixed to the

gear wheels

37 and 135, respectively. When, during the continuous counterclockwise rotation of the driving shaft 85, the single stop 123 of the hub member 113 and one of the stops 127 of the hub member 117 are blocked by means hereinafter described, the spring members 109 forming a part of the clutches 97 and are held in expanded disengaged relationship with their respective disks 93, to thereby maintain the cam shaft 101 and the gear wheel 135 in an inactivated state. In like manner, when, during the rotation of the cam shaft 101 by the driving shaft 85, one of the stops 125 of the hub member is blocked by means hereinafter described, the spring 109 forming a part of the clutch 99 is held in expanded disengaged relationship with the disk 107, to thereby maintain the gear wheel 37 fixed to the housing member 119 in an inactivated state. When the stop 123 or the active one of the stops 127 or is released, however, the spring member 109 of the corresponding clutch is permitted to contract into gripping relationship with the associated

disk

93 or 107 to thereby rotationally activate the cam shaft 101 or the gear wheel or 37 in a counterclockwise direction. The backup stop 129 of the housing portion 103 and the backup stops 131 and 133 of the

housing members

119 and 121, in cooperation with biased

limit arms

137, 139 and 141, respectively, serve to prevent the clockwise rotational overthrow of their respective housing members when a stop of their associated hub members are limited in their counterclockwise rotation, the termination of such counterclockwise rotation being effective to expandably disengage the corresponding spring member 109 from their associated

disks

93 or 107.

Each of the cams 105A through 105F of the cam shaft assembly 101 is cooperably associated with a separate cam follower lever 151 pivotally supported by a shaft 153 which is journaled within a pair of

frame members

143 and 145. Each of the cam follower levers 151 is provided with a lower arcu ate prong 157 that cooperates with the raised portion of its respective cam 105, and with an upper arcuate prong 159 that cooperates with a recess formed in a companion follower portion of each cam disposed at a point I80 removed from such raised portion, as shown in FIGS. 8 and 9. Each of the cam follower levers 151 is also pivotally connected by means of a pin 161 to a sensing arm 74 corresponding thereto, such connection occurring at the extremity thereof opposite the extremity comprising said arcuate prongs. Each of the sensing arms 74 is biased in a clockwise direction on its connecting pin 161 by means of a spring 163 which is anchored at one end to an aperture formed in the sensing arm and at the other end to a shaft 165 also supported by the

frame members

143 and 145. A slot 167 formed in the rearmost extremity of each of the sensing arms 74 is cooperably engaged with a

short shaft

169 or 171, the particular functions of which are hereinafter described. Each of the sensing arms 74 is also provided with an upwardly projecting abutment 173 formed on the frontmost extremity thereof, said abutment being cooperably associated with the depending projection 72 of its associated longitudinal slide 71 of the keyboard. During the counterclockwise rotation of the cam shaft 101 and the cams 105A through 1051 the cam follower levers 151 associated therewith are rotated in a counterclockwise direction on the shaft 153, as the raised portions of the cams contactably activate their respective lower arcuate prongs 157. This counterclockwise rotation of the cam follower levers 151 is effective to rotate the sensing arms 74 a minimal counterclockwise distance on their respective pins 161, whenever the abutments 173 thereof are unrestricted by the depending projections 72 of their forwardly positioned keyboard slides 71, such minimal counterclockwise rotation being realized under such circumstances without displacing the

short shafts

169 and 171 from their normal home positions. When, during this counterclockwise rotation of a given cam follower lever 15], its associated sensing arm 74 is blocked against a minimal counterclockwise rotation by the depending projection 72 of its rearwardly positioned keyboard slide 71, such counterclockwise rotation of the lever 15] is effective to rotate the sensing arms 74 a minimal clockwise distance to thereby elevate the

short shaft

169 or 171 for an interval of time proportionate to the time the lower arcuate prong of the lever is in contact with the raised portion of its respective cam 105.

A hub member 175 shown in FIGS. 10B and is rotatably disposed on a shaft 155 (FIG. 10A) supported by the

frame members

143, 145, and 147, said hub member being provided with a pair of arms 177 connecting a cylindrical housing 179 thereto, said cylindrical housing serving to rigidly support the short shaft 169 which extends leftwardly (as viewed in FIG. 10B) into engaged relationship with the slots 167 of the sensing arms 74 associated with the cams 105A through 105D. A latch arm 181 is connected to the cylindrical housing 179 and is rotatable with the hub member 175 on the shaft 155. The rearmost extremity of the latch arm 181 is disposed in cooperating relationship with the stops 125 of the friction clutch 99, assuming a blocking relationship therewith when the short shaft 169 is situated in its normal home position and a cleared relationship therewith when the short shaft is located in an elevated positionv It can thus be seen that the stops 125 of the clutch 99 are released by the latch arm 181 whenever, during the rotation of the cam shaft 101, one or more of the longitudinal slides 71A through 71D is located in its rearwardly translated position, such released condition being maintained for a differential period of time corresponding to the time at least one of the cams 105A through 105D remains in camming contact with its associated cam follower lever 151. The hub member 175 and short shaft 169 supported thereby are biased in a clockwise direction on the shaft 155 by spring means which is not shown in the drawings. As a consequence of such bias, the latch arm 181 is rotatably returned to a blocking position relative to the stops 125 when the short shaft is released from its elevated position by the cams 105A through 105 D. As hereinbefore described. release of the stops 125 is effective to couple the gear wheel 37 with the rotating disk 107 of the cam shaft assembly 101, and blockable contact of the latch arm 18] with one of the rotating stops 125 is effective to disengage the spring member 109 of the clutch 99 from the disk 107 and to thereby inactivate the gear wheel 37.

A hub member 183, (FIG. 10A), which is also rotatably disposed on the shaft 155, in the proximity of the shafts leftmost extremity, is provided with a pair of arms 185 connecting a cylindrical housing 187 thereto, said cylindrical housing serving to rigidly support the short shaft 171 which extends rightwardly therefrom into engaged relationship with the slots 167 of the sensing arms 74 associated with the

cams

105E and 105F. A latch arm 189 is connected to the cylindrical housing 187 and is rotatable with the hub member 183 on the shaft 155. The rearmost extremity of the latch arm 189 is disposed in cooperating relationship with the stops 127 of the friction clutch 95, assuming a blocking relationship therewith when the short shaft 171 is located in its normal home position and a cleared relationship therewith when the short shaft is located in an elevated position. The stops 127 of the clutch 95 are ac cordingly released by the latch arm 189 whenever, during the rotation of the cam shaft 101, either of the keyboard slides 71E or 71F is located in its rearwardly translated position, such released condition being maintained for a differential period corresponding to the time one of the

cams

105E or 105F remains in camming contact with its associated cam follower lever 151. The hub member 183 and short shaft 171 are also biased in a clockwise direction by spring means not shown, and, as a consequence of this bias, the latch arm 189 is returned to a blocking position relative to one of the stops 127 when the short shaft is released from its elevated position by the

cams

105E and 105F. Release of the stops 127 is effective to couple the gear wheel 135 with a rotating disk 93 of the driving shaft 85, and blockable contact of the latch arm 189 with one of the rotating stops 127 is effective to disengage the disk 93 and to thereby inactivate the gear wheel 135. As was disclosed in a preceding section dealing with the rearward ac tivation of the slides 71A through 71F of the keyboard, the slide 71F is activated rearwardly each time a listing key of the keyboard is depressed. The gear wheel is accordingly activated for a predetermined interval upon the depression of each of the listing keys of the keyboard, such activation resulting from the elevation of the short shaft 171 by the sensing arm 74 associated with the cam 105F.

The sensing member 83, to which reference was made in connection with the keyboard slide 710, is rotatably supported by the shaft and is biased in a counterclockwise direction thereon by a spring 191 connected thereto and to a stud fixed to the frame member 143. A slot 193 formed in this sensing member accommodates the rotation of the short shaft 171 relative to the shaft 155, and the rearmost extremity of this sensing member is disposed in cooperating relationship with the single stop 123 of the friction clutch 97, The sensing member 83 is normally held in a clockwise rocked position on the shaft 155, against the bias of the spring 191, by the depending projection 75 and the biased pivotal arm 77 of the forwardly positioned power slide 71G, as shown in FIG. 6. Depression of any one of the listing keys of the keyboard (excluding the decimal point key) results in the rearward activation of the slide 710, such activation being effective to release the sensing member 83 to the bias of the spring 191, the upright extension of the sensing member moving into interposed relationship with the projection 75 and the pivotal arm 77 of the slide 71G, and the sensing member itself experiencing a counterclockwise rotation on the shaft 155 to release the stop 123 of the hub member 113. As a consequence of such release, the cam shaft 101 is coupled to the rotating driving shaft 85 by means of the clutch 97, and the cam shaft 101 is rotated one complete revolution in a counterclockwise direction. During such revolution, the sensing member 83 is rotated in a clockwise direction through the camming action of a raised portion of the housing 103 on an upright arm of the sensing member. The rearmost extremity of the sensing member 83 is accordingly repositioned in blocking relationship with the stop 123, and the upright extension of the sensing member is again blockingly contacted by the depending projection 75 and the pivotal arm 77 of the forwardly restored power slide 710. The backup stop 129 formed in the housing portion 103 provides clearance as between the hous ing 103 and the upright arm 195 when the cam shaft assembly 101 is located in its normal home position, such clearance being essential to the counterclockwise release rotation of the sensing member in relation to the stop 123.

The selector carriage 21 shown in FIGS. 10B and 17 is comprised of a plurality of ordinally arranged toothed members 23 disposed between the rightmost of the frame members 31 and the frame member 33. Each of these toothed members, as was previously indicated, is provided with an arcuate webbed portion extending for approximately one half of its circumference, and a toothed portion consisting of 10 teeth extending over the remaining half of its circumference. The arcuate webbed portion of each member is provided with readable numeric values ranging from 0 through 9, such values being readable through a rectangular aperture formed in the case of the calculating machine. The toothed members 23 are rotatably supported by a grooved shaft 199 journaled within the frame member 143 (FIG. 10A) and a frame member 149 (FIG. 108). A shaft 201, to the opposite ends of which a pair of cams 203 (FIG. 17) are keyed, is also journaled within the

frame members

143 and 149, such shaft passing through a slot 205 formed in each of the carriage frame members and through elongated arcuate slots formed in the toothed members 23. The frame members 31 and 33 (FIG. 10B) are connected to form a unitary carriage by means of a plate 209 and a shaft 207. A shaft 211 (FIG. 17) passes through the carriage frame members and extends outwardly therefrom to a point of fixed termination in a pair of cam followers 213 which are rotatably supported by the grooved shaft 199 and disposed inwardly adjacent the

frame members

143 and 149. This shaft 211 also serves to rotatably support a plurality of ordinally arranged intermediate gear wheels 25 disposed between the innermost frame member 31 and the frame member 33. These intermediate gear wheels are maintained in cooperating relationship with the teeth of the toothed members 23, and are selectively engageable with the receiving pinions 27 of the calculating machine according to the number of units of leftward translation that are experienced by the selector carriage during the entry of digit values. The engagement of the inter mediate gear wheels with the receiving pinions is accomplished by the counterclockwise rotation (as viewed in FIG. 17) of the selector carriage on the grooved shaft 199, such counterclockwise rotation being effectuated by the rotation of the shaft 201 and the camming action of the cams 203 on the cam followers 213, rotation of the shaft 201 being achieved by means neither shown nor described in the present disclosure.

The grooved shaft 199 is provided with a spiral groove extending over its full length. A sleeve 215 (FIG. B) loosely fitted on the shaft 199 and snugly fitted between the frame members 31 of the selector carriage is provided with an internally disposed spiral groove corresponding to the groove of the shaft 199. The groove of the sleeve 215 in cooperation with that portion of the groove of the shaft transitionally located between the frame members 31 serves to house a plurality of ball bearings sufficient in number to occupy the linear distance between said carriage frame members. The sleeve 215 is also provided with a depending forked member 217 which straddles the shaft 201 as the selector carriage is translated in either direction. The spiral groove of the shaft 199, in cooperation with the sleeve 215 and jointly housed ball bearings, is effective to translate the selector carriage in a leftward direction when the shaft 199 is rotated in a counterclockwise direction (as viewed in FIG. 10A), and to translate the carriage in a rightward direction when the shaft is rotated in a clockwise direction.

A slideable shaft 219 (FIG. 10A) supported by the

frame members

143 and 145 and an auxiliary frame member 237 provides rotational support for three associated

gear wheels

221, 223, and 225, said gear wheels being maintained in laterally fixed position by the

frame members

143 and 237. The gear wheel 223 is maintained in cooperating relationship with the gear wheel 135 of the friction clutch 95, and is selectively coupleable with either the

gear wheel

225 or 221 by means of a minimal translation of the shaft 219 in a rightward or leftward direction, respectively. The shaft 219 is provided with a fixed key which is engageable with companion internal keyways in the

gear wheels

221 and 223, when the shaft is located in its leftmost position, and engageable with companion internal keyways in the

gear wheels

223 and 225 when the shaft is located in its rightmost position. A sleeve 227 comprising a pair of spaced-apart

gear wheels

229 and 231 is fixed to the leftmost extremity of the grooved shaft 199, lehwardly adjacent the frame member 143. The gear wheel 229 is maintained in cooperating relationship with the gear wheel 225 of the slideable shaft 219, and the gear wheel 231 is disposed in cooperating relationship with an intermediate gear 233 rotatably supported by a short shaft 235 fixed to the frame member 143. The intermediate gear 233 is maintained in cooperating relationship with the gear wheel 221 of the slidesble shaft 219. The latter shaft is also provided with a pair of fixed spaced-apart actuators 239 and 241, the rightmost actuator 239 having a pair of slotted arms disposed in straddling relationship with a guide shaft 243, and the leftmost actuator 241 having a slotted arm cooperably engaged with a groove formed in a roller 247 carried thereupon. A profiled cam 245 (FIG. 10B) fixed to the cam shaft assembly 101 in interposed relationship between the pair of slotted arms of the rightmost actuator 239 is so profiled that the counterclockwise rotation of the cam shaft will effectuate a rightward translation of the slideable shaft 219 to thereby engage the key thereof with the companion key-ways of the

gear wheels

223 and 225, the resultant coupling of the latter gear wheels being effective to translate the selector carriage 21 in a leftward direction when the gear wheel 135 of friction clutch is rotated one complete revolution in a counterclockwise direction.

Means not directly related to the present invention are provided for rotating the shaft 201 of the selector carriage in a clockwise direction (as viewed in FIG. 10A) when all of the digits of an amount to be entered have been registered in the toothed members 23, such clockwise rotation of the shaft being efiective to engage the intermediate gear wheels 25 (FIGS. 1 and 17) with the receiving pinions 27 (FIG. 17). During the clockwise rotation of the shaft 201, a profiled cam 249 fixed to the leftmost extremity of the shaft contacts a curved surface of the grooved roller 247 and thereby translates the shaft 219 to the left to effectively engage the key thereof with the companion keyways of the gear wheels 22] and 223. With the

gear wheels

221 and 223 coupled in this fashion, the counterclockwise rotation of the gear wheel 135 will effectuate a rightward return translation of the selector carriage by means of the gear train consisting of

gear wheels

221, 233, and 231.

OPERATION OF THE ENTRY APPARATUS As previously stated, depression of any one of the listing keys of the keyboard, including keys 1 through 9, the 000 key, the 00 key, and the 0 key, is effective to activate the keyboard slide 716 a minimal rearward distance (to the left as shown in FIGS. 6 and 7), to thereby release the sensing member 83 to the control of the spring 191 (FIG. 10A), the resultant counterclockwise rotation of the sensing member being effective to engage the friction clutch 97. The cam shaft 101 is accordingly coupled to the rotating driving shaft 85 for one complete revolution therewith. During this revolution the cams 105A through 105F effectively activate their respective cam follower levers 151 in a counterclockwise direction on the shaft 153, their associated sensing arms 74 (FIG. 108) being elevated to either idle in a counterclockwise direction when unrestricted by slides 71A through 711-" (FIG. 3), or to activatably elevate the short shaft 169 (FIG. 108) or 171 (FIG. 10A) with which they are engaged when blockingly restricted by their associated and rearwardly positioned slides 71. Elevation of the short shaft 169 is effective to couple the gear wheel 37 with the rotating cam shaft 101 by means of clutch 99, such coupling continuing for an interval of time corresponding to the time a sensing arm 74 is held in an elevated state by cams 105A through 105D. Elevation of the short shaft 171 (FIG. 10A) is effective to couple the gear wheel with the rotating driving shaft 85 by means of the clutch 95, such coupling continuing for an interval of time corresponding to the time a sensing arm 74 is held in an elevated state by the cams 1055 and 1051-.

When the 1 key of the keyboard is depressed, the cam 105A elevates the short shaft 169 for an interval of time sufiicient to advance a toothed member 23 of the selector carriage a onetooth distance, by means of the gear wheel 37, the single pinion 35 and the intermediate gear wheel 25 associated with the toothed member. When the 2 key is depressed, the cam 105B elevates the short shaft 169 for an interval of time sulficient to advance a toothed member 23 a two-tooth distance. In like fashion, when the 4 or 8 keys are depressed, the

cam

105C or 1050 elevates the shaft 169 for an interval of time sufficient to advance a toothed member a four-tooth or eighttooth distance, respectively.

Depression of the 3 key is effective to rearwardly activate the slides 71A and 71B, the

cams

105A and 1058 being thereby rendered effective to hold the short shaft 169 in an elevated state for an interval of time sufficient to advance a toothed member 23 a three-tooth distance, the cam 105A producing a one-tooth advancement and the cam 1058 producing a two-tooth advancement. Depression of the 5 key is effective to activate the

slides

71A and 71C into blocking relationship with their respective sensing arms 74, the

cams

105A and 105C being thereby rendered effective to hold the shaft 169 in an elevated state for an interval sufiicient to ad vance a toothed member 23 a five-tooth distance, the cam 105A producing a one-tooth advancement and the cam 105C producing a four-tooth advancement. Depression of the 7 key is effective to activate the

slides

71A, 71B and 71C into blocking relationship with their respective sensing arms 74, the

cams

105A, 105B and 105C being thereby rendered effective to hold the shaft 169 in an elevated position for an interval sufficient to advance a toothed member 23 a seven-tooth distance, the cam 105A producing a one-tooth advancement, and the

cams

105B and 105C producing a two-tooth and fourtooth advancement, respectively. Depression of the 9 key is effective to activate the slide 71A and 71D into blocking relationship with their respective sensing arms 74, the cams 105A and 105D being rendered effective to hold the shaft 169 in an elevated position for an interval sufficient to advance a toothed member 23 a nine-tooth distance, the cam 105A producing a one-tooth advancement and the cam 105D producing an eight-tooth advancement.

As stated in a preceding section, the depression of each of the listing keys 1 through 9, in addition to activating selected ones of the slides 71A through 71D, is also effective to activate the slide 71F into blocking relationship with its associated sensing arm 74, the rotation of the cam 1051- being thereby rendered effective to elevate the short shaft 171 for an interval of time sufficient to translate the selector carriage 21 a one-unit distance in a leftward direction, such elevation of the shaft and leftward translation of the carriage occurring during the last 36 degrees of rotation of the cam shaft 101 when the raised portion of the cam lF is in contact with the lower arcuate prong of its associated cam follower lever 151. It should be pointed out that the profiled cam 245 (FIG. B) of the cam shaft assembly W1 is effective, during the early portion of the shafts rotation, to translate the slideable shaft 219 in a rightward direction to thereby couple the

gear wheels

223 and 225 for a leftward translation of the selector carriage. As a result of the above-described one-unit leftward translation of the selector carriage, the toothed member 23 rightwardly adjoining the toothed member which received the previously registered value is positioned in cooperable alignment with the single pinion 35 preparatory to the entry of the next lower order digit.

Depression of one of the three 0 keys is effective to initiate a one revolution rotation of the cam shaft 101 during which the cams [05A through 105D are ineffective for coupling the gear wheel 37 for the advancement of a toothed member 23, but wherein the cams 105E and/or 105F are rendered effective for producing a one, two or three unit leftward translation of the selector carriage by means of the

gear wheels

135, 223, 225, and 229. When the 0 key is depressed, the cam 105F is rendered effective to elevate the short shaft 171 for an interval of time sufficient to produce a one-unit leftward translation of the carriage, in similar fashion to that resulting from the depression of the keys 1 through 9. When the 00 key is depressed, the cam 105E is rendered effective to hold the shaft l7l in an elevated state for an interval sufficient to produce a two-unit leftward translation of the carriage, such cam, as previously indicated, having a raised portion extending over one fifth (or 72") of its circumference. When the 000 key is depressed, the cams 1055 and 105F will combine to hold the short shaft 171 in an elevated state for an interval of time sufficient to produce a three-unit leftward translation, the cam 105E producing a two-unit translation and the cam l05F producing a one-unit translation.

Depression of the decimal point key (shown in FIG. 2) is ineffective to produce either an advancement of a toothed member 23 or a leftward translation of the carriage, such decimal point key relating more specifically to a separate aspect of the calculating machine into which the preferred embodiment of the present invention is incorporated. in like manner this calculating machine provides for a differential leftward translation of the selector carriage, through means not herein disclosed, said differential translation being effective to cooperably align the toothed member 23 containing the least significant whole digit (non-decimal) of the entered amount with a predetermined order of the receiving pinions 27. Such difi'erential translating means, however, provide but still another mode of elevating the short shaft 171 and of coupling the gear wheel 135 with the rotating driving shaft for a differential leftward and full return rightward translation of the selector carriage.

It can thus be seen that the preferred embodiment of the invention is effective for entering decimal amounts in a calculating machine by means of improved mechanism which is also readily adaptable for receiving and converting binary information such as would be transmitted from data processing equipment. As an example of how this improved entry mechanism may be converted for receiving binary information, well known circuitry in association with solenoid means could be employed as substitute means for blockably activating the sensing arms 74 associated with the cams A through l05D, said cams and said sensing arrns having binary significance in that they are separately qualified for entering decimal values of l, 2, 4 and 8 and collectively qualified for entering decimal values of 3, S, 7 and 9.

While the invention in improved entry apparatus has been shown and described in considerable detail, it will be understood that many variations thereof may be made by those skilled in the art without departing from the true spirit and scope of the invention.

What is claimed is:

1. In a calculating machine having a ten key keyboard and continuous motive means, improved entry apparatus effective for entering decimal information by means of said keyboard, said entry apparatus comprising:

a. a translatable selector carriage having a frame and a plurality of rotatable toothed members representing decimal orders,

b. means responsive to said keyboard and to said motive means for individually and differentially advancing said toothed members, said advancing means comprising a predetermined number of sets of associated elements that are separately operable in the entry of decimal values 1, 2, 4 and 8 in said individual toothed members, and operable in combination in the entry of decimal values 3, S, 7 and 9, and

c. means responsive to said keyboard and to said toothed member advancing for differentially translating said selector carriage, said means being preparatorily effective for entering the next lower order decimal value and effective also for registering in said selector carriage the absence of values in one or more decimal orders, said entry apparatus by reason of said predetermined sets of elements of said toothed member advancing means being also readily adaptable for entering binary information into said calculating machine, said sets of elements having binary significance in that they correspond to the binary digits 1, 2, 4 and 8.

2. The entry apparatus defined in claim I wherein said means for differentially advancing said toothed members comprises:

a. a first gear wheel cooperable with individual toothed members of said selector carriage,

h. first coupling means responsive to said keyboard for connecting said first gear wheel to said continuous motive means, said connection resulting in the rotational advancement of an individual toothed member of said selector carriage through the unidirectional rotation of said first gear wheel, and

c. first controlling means responsive to said keyboard and to said first coupling means for regulating the interval of rotation of said first gear wheel, said interval of rotation being effective to advance an individual toothed member a differential rotational distance representing a selected decimal value.

The entry apparatus defined in claim 2 wherein said means for differentially translating said selector carriage comprises:

a first shaft rotatably supporting said toothed members within said frame, said first shaft having a spiral groove longitudinally formed therein,

. a second gear wheel associated with said motive means and with said first shaft,

. second coupling means for differentially connecting said second gear wheel to said first shaft for a bidirectional translation of said selector carriage, said difi'erential connection being effective for rotating said first shaft in a first and a second direction as motivated by said second gear wheel, and

. second controlling means responsive to said keyboard coupling means comprises:

a driving second shaft cooperably responsive to said motive means for continuous rotation therewith, said second shaft having a pair of spaced-apart disks fixed thereto,

. a driven third shaft having a plurality of cams and a disk fixed thereto, said cams forming a part of said first and said second controlling means,

. first clutch means effective for resiliently connecting said third shaft to said second shaft for one complete revolution therewith, said first clutch being disposed in cooperating relationship with a first of said pair of disks of said driving second shaft,

. means responsive to said keyboard effective for activating said first clutch means, and effective also for deactivating said clutch means upon completion of said one revolution rotation of said driven third shaft, and

, second clutch means responsive to said revolution of said third shaft and to said first and second controlling means for resiliently connecting said first gear wheel to said third shaft, said second clutch being disposed in cooperating relationship with said disk of said driven third shaft.

The entry apparatus defined in claim 4 wherein said second coupling means for differentially connecting said second gear wheel to said first shaft comprises:

third clutch means responsive to said revolution of said driven third shaft and to said second controlling means for resiliently connecting said second gear wheel to said driving second shaft, said third clutch means being disposed in cooperating relationship with the second of said pair of disks fixed to said driving second shaft,

. a slideable fourth shaft providing rotatable support for a a sixth gear wheel fixed to said first shaft and disposed in cooperating relationship with said fifth gear wheel,

. a seventh gear wheel fixed to said first shaft and disposed in coplanar and nonengaging relationship with said third gear wheel, and

, an eighth gear wheel rotatably supported by an abbreviated fifth shaft and disposed in cooperating relationship with said third and said seventh gear wheels, said unidirectional rotation of said second gear wheel being effective, when said slideable fourth shaft is located in its rightmost position, to rotate said first shaft in said first direction by means of said fourth, fifth and sixth gear wheels, and effective, when said fourth shaft is located in its leftmost position, to rotate said first shaft in said second direction by means of said fourth, third, eighth and seventh gear wheels.

6. The entry apparatus defined in claim 5 wherein said first, said second and said third clutch means are each comprised a. a first, second, or third hub member, respectively, having at least one stop formed on the periphery thereof, said hub member being rotatably supported by said second or said third shaft,

b. a first, second, or third cylindrical housing member,

respectively, rotatably supported by said second or said third shaft in adjacent coaxial relationship with said associated hub member, said housing member being provided with at least one backup stop and either connected to or provided with actuating means consisting of said third shaft, said first gear wheel, or said second gear wheel, respectively, and

. a spring member disposed in coplanar and encompassing relationship with one of said disks of said second or said third shafts, said spring member having a plurality of coils terminating in a pair of offset extensions protruding outwardly in opposite directions therefrom, one of said extensions being snugly fitted in a slot formed in said hub member and the other of said extensions being snugly fitted in a slot formed in said cylindrical housing member, the arrangement being such that said spring member is held in expanded and disengaged relationship with the peripheral surface of its associated rotating disk when a stop of its associated hub member is blockably limited, said spring member being released into a contracted and gripping relationship with said peripheral surface when said stop is released from said blockably limited condition.

7. The entry apparatus defined in claim 6 wherein said means for activating and deactivating said first clutch means comprises:

a. a sensing member rotatably supported by a sixth shaft and biased in a counterclockwise direction thereon by spring means, said member being provided with an upright extension formed on its frontmost extremity, said upright extension being disposed in blockable relationship with said keyboard, the rearmost extremity of said sensing member being disposed in blocking relationship with said stop of said first hub member of said first clutch means when said upright extension is blockably limited by said keyboard, and being also rockably displaced from said stop when said sensing member is released by said keyboard to the control of said spring means, said rockable displacement of said sensing member from said stop being effective to release said spring member of said first clutch means into gripping relationship with said first disk of said driving second shaft and to thereby couple said driven third shaft connected to said first cylindrical housing member of said first clutch means with said driving second shaft, and

b. an upright arm attached to said sensing member in cooperating relationship with said backup stop of said first cylindrical housing of said first clutch means, said backup stop being defined by the termination of a raised camming surface formed on said first cylindrical housing, said camming surface in cooperation with said upright arm being effective, during said unidirectional rotation of said driving second and driven third shafts, to rotate said sensing member into blocking relationship with said stop of said first hub member and to reestablish said blockable relationship thereof with said keyboard, said blocking

Claims

1. In a calculating machine having a ten key keyboard and continuous motive means, improved entry apparatus effective for entering decimal information by means of said keyboard, said entry apparatus comprising: a. a translatable selector carriage having a frame and a plurality of rotatable toothed members representing decimal orders, b. means responsive to said keyboard and to said motive means for individually and differentially advancing said toothed members, said advancing means comprising a predetermined number of sets of associated elements that are separately operable in the entry of decimal values 1, 2, 4 and 8 in said individual toothed members, and operable in combination in the entry of decimal values 3, 5, 7 and 9, and c. means responsive to said keyboard and to said toothed member advancing means for differentially translating said selector carriage, said means being preparatorily effective for entering the next lower order decimal value and effective also for registering in said selector carriage the absence of values in one or more decimal orders, said entry apparatus by reason of said predetermined sets of elements of said toothed member advancing means being also readily adaptable for entering binary information into said calculating machine, said sets of elements having binary significance in that they correspond to the binary digits 1, 2, 4 and 8.

2. The entry apparatus defined in claim 1 wherein said means for differentiaLly advancing said toothed members comprises: a. a first gear wheel cooperable with individual toothed members of said selector carriage, b. first coupling means responsive to said keyboard for connecting said first gear wheel to said continuous motive means, said connection resulting in the rotational advancement of an individual toothed member of said selector carriage through the unidirectional rotation of said first gear wheel, and c. first controlling means responsive to said key-board and to said first coupling means for regulating the interval of rotation of said first gear wheel, said interval of rotation being effective to advance an individual toothed member a differential rotational distance representing a selected decimal value.

3. The entry apparatus defined in claim 2 wherein said means for differentially translating said selector carriage comprises: a. a first shaft rotatably supporting said toothed members within said frame, said first shaft having a spiral groove longitudinally formed therein, b. a second gear wheel associated with said motive means and with said first shaft, c. second coupling means for differentially connecting said second gear wheel to said first shaft for a bidirectional translation of said selector carriage, said differential connection being effective for rotating said first shaft in a first and a second direction as motivated by said second gear wheel, and d. second controlling means responsive to said key-board and to said first coupling means, said means cooperating with said second coupling means to regulate the interval of rotation of said second gear wheel and said first shaft as said second gear wheel is unidirectionally rotated by said continuous motive means, and to thereby translate said selector carriage a differential distance suitable either for entering a decimal value in the next lower order toothed member or for registering the absence of a value in one or more orders.

4. The entry apparatus defined in claim 3 wherein said first coupling means comprises: a. a driving second shaft cooperably responsive to said motive means for continuous rotation therewith, said second shaft having a pair of spaced-apart disks fixed thereto, b. a driven third shaft having a plurality of cams and a disk fixed thereto, said cams forming a part of said first and said second controlling means, c. first clutch means effective for resiliently connecting said third shaft to said second shaft for one complete revolution therewith, said first clutch being disposed in cooperating relationship with a first of said pair of disks of said driving second shaft, d. means responsive to said keyboard effective for activating said first clutch means, and effective also for deactivating said clutch means upon completion of said one revolution rotation of said driven third shaft, and e. second clutch means responsive to said revolution of said third shaft and to said first and second controlling means for resiliently connecting said first gear wheel to said third shaft, said second clutch being disposed in cooperating relationship with said disk of said driven third shaft.

5. The entry apparatus defined in claim 4 wherein said second coupling means for differentially connecting said second gear wheel to said first shaft comprises: a. third clutch means responsive to said revolution of said driven third shaft and to said second controlling means for resiliently connecting said second gear wheel to said driving second shaft, said third clutch means being disposed in cooperating relationship with the second of said pair of disks fixed to said driving second shaft, b. a slideable fourth shaft providing rotatable support for a third, fourth and fifth gear wheel, said fourth gear wheel being maintained in cooperating relationship with said second gear wheel, and said third and said fifth gear wheels being maintained in oppositely adjacent parallel relationship to said fourth gear wheel, said fourth shaft having a key of predetermined length fixed thereto, said key being permanently and slideably engaged with a keyway formed in said fourth gear wheel and selectively engageable with companion keyways formed in said third and said fifth gear wheels when said fourth shaft is translated to its leftmost and rightmost positions, respectively, c. a sixth gear wheel fixed to said first shaft and disposed in cooperating relationship with said fifth gear wheel, d. a seventh gear wheel fixed to said first shaft and disposed in coplanar and non-engaging relationship with said third gear wheel, and e. an eighth gear wheel rotatably supported by an abbreviated fifth shaft and disposed in cooperating relationship with said third and said seventh gear wheels, said unidirectional rotation of said second gear wheel being effective, when said slideable fourth shaft is located in its rightmost position, to rotate said first shaft in said first direction by means of said fourth, fifth and sixth gear wheels, and effective, when said fourth shaft is located in its leftmost position, to rotate said first shaft in said second direction by means of said fourth, third, eighth and seventh gear wheels.

6. The entry apparatus defined in claim 5 wherein said first, said second and said third clutch means are each comprised of: a. a first, second, or third hub member, respectively, having at least one stop formed on the periphery thereof, said hub member being rotatably supported by said second or said third shaft, b. a first, second, or third cylindrical housing member, respectively, rotatably supported by said second or said third shaft in adjacent coaxial relationship with said associated hub member, said housing member being provided with at least one back-up stop and either connected to or provided with actuating means consisting of said third shaft, said first gear wheel, or said second gear wheel, respectively, and c. a spring member disposed in coplanar and encompassing relationship with one of said disks of said second or said third shafts, said spring member having a plurality of coils terminating in a pair of offset extensions protruding outwardly in opposite directions therefrom, one of said extensions being snugly fitted in a slot formed in said hub member and the other of said extensions being snugly fitted in a slot formed in said cylindrical housing member, the arrangement being such that said spring member is held in expanded and disengaged relationship with the peripheral surface of its associated rotating disk when a stop of its associated hub member is blockably limited, said spring member being released into a contracted and gripping relationship with said peripheral surface when said stop is released from said blockably limited condition.

7. The entry apparatus defined in claim 6 wherein said means for activating and deactivating said first clutch means comprises: a. a sensing member rotatably supported by a sixth shaft and biased in a counterclockwise direction thereon by spring means, said member being provided with an upright extension formed on its frontmost extremity, said upright extension being disposed in blockable relationship with said keyboard, the rearmost extremity of said sensing member being disposed in blocking relationship with said stop of said first hub member of said first clutch means when said upright extension is blockably limited by said keyboard, and being also rockably displaced from said stop when said sensing member is released by said keyboard to the control of said spring means, said rockable displacement of said sensing member from said stop being effective to release said spring member of said first clutch means into gripping relationship with said first disk of said driving second shaft and to thereby couple said driven third shaft connected to said first cylindrical housing member of said first clutch means with said driving second shaft, and b. an upright arm attached to said sensIng member in cooperating relationship with said back-up stop of said first cylindrical housing of said first clutch means, said back-up stop being defined by the termination of a raised camming surface formed on said first cylindrical housing, said camming surface in cooperation with said upright arm being effective, during said unidirectional rotation of said driving second and driven third shafts, to rotate said sensing member into blocking relationship with said stop of said first hub member and to re-establish said blockable relationship thereof with said keyboard, said blocking relationship with said stop being effective to deactivate said first clutch and to terminate said rotation of said driven third shaft after one complete revolution thereof.

8. The entry apparatus defined in claim 7 wherein said first controlling means for regulating said interval of rotation of said first gear wheel comprises: a. a first, second, third and fourth cam of said plurality of cams fixed to said driven third shaft of said first coupling means, b. a plurality of cam follower levers corresponding to said first, second, third and fourth cams, said levers being rotatably supported by a seventh shaft in cooperating relationship with said cams, and c. a plurality of sensing arms corresponding to said cams and pivotally connected to said cam follower levers, each of said sensing arms being provided with an upwardly directed abutment formed on its frontmost extremity and a slot formed in its rearmost extremity, said cam follower levers and associated sensing arms each being biased in a clockwise direction on said seventh shaft by means of a spring connected to said sensing arm and to an eighth shaft, said cams during said one revolution rotation of said driven third shaft being effective to rotate said cam follower levers in a counterclockwise direction on said seventh shaft and to thereby elevate said corresponding sensing arms a predetermined minimal distance against the bias of their associated springs.

9. The entry apparatus defined in claim 8 wherein said first controlling means additionally comprises: a. a fourth hub member rotatably supported by said sixth shaft, said hub member having a pair of parallel and spaced-apart arms extending outwardly therefrom, b. a fourth cylindrical housing connected to said pair of arms of said fourth hub member, c. an abbreviated ninth shaft securely positioned within said fourth cylindrical housing for unitary rotation therewith about said sixth shaft, said abbreviated shaft extending outwardly from said housing into engaged relationship with said slots formed in said sensing arms associated with said first, second, third and fourth cams fixed to said third shaft of said first coupling means, and d. a first latch arm rotatably supported by said sixth shaft and connected to said abbreviated ninth shaft and to said fourth cylindrical housing, said latter housing, said fourth hub member, and said abbreviated shaft being biased in a clockwise direction on said sixth shaft such that said first latch arm is held in blocking contact with one of said stops formed in said second hub member of said second clutch means, said blocking contact being effective to maintain said spring member of said second clutch means in said expanded and disengaged relationship with said disk fixed to said driven third shaft, and to thereby maintain said first gear wheel connected to said second cylindrical housing of said second clutch means in disengaged relationship with said driven third shaft.

10. The entry apparatus defined in claim 9 wherein said second controlling means for regulating said interval of rotation of said second gear wheel comprises: a. a fifth and a sixth cam of said plurality of cams fixed to said driven third shaft of said first coupling means, b. a pair of cam follower levers rotatably supported by said seventh shaft in cooperating relationship with said fifth and said sixth cams, and c. a pair of sEnsing arms corresponding to said fifth and said sixth cams and pivotally connected to said pair of cam follower levers, each of said sensing arms being provided with an upwardly directed abutment formed on its frontmost extremity and a slot formed in its rearmost extremity, said cam follower levers and associated sensing arms each being biased in a clockwise direction on said seventh shaft by means of a spring connected to said sensing arm and to said eighth shaft, said cams during said one revolution rotation of said driven third shaft being effective to rotate said cam follower levers in a counterclockwise direction on said seventh shaft and to thereby elevate said corresponding sensing arms a predetermined minimal distance against the bias of their associated springs.

11. The entry apparatus defined in claim 10 wherein said second controlling means additionally comprises: a. a fifth hub member rotatably supported by said sixth shaft, said hub member having a pair of parallel and spaced-apart arms extending outwardly therefrom, b. a fifth cylindrical housing connected to said pair of arms of said fifth hub member, c. an abbreviated tenth shaft securely positioned within said fifth cylindrical housing for unitary rotation therewith about said sixth shaft, said abbreviated shaft extending outwardly from said housing into engaged relationship with said slots formed in said sensing arms associated with said fifth and said sixth cams fixed to said driven third shaft of said first coupling means, and d. a second latch arm rotatably supported by said sixth shaft and connected to said abbreviated tenth shaft and to said fifth cylindrical housing, said latter housing, said fifth hub member and said abbreviated shaft being biased in a clockwise direction on said sixth shaft such that said second latch arm is held in blocking contact with one of said stops formed in said third hub member of said third clutch means, said blocking contact being effective to maintain said spring member of said third clutch in said expanded and disengaged relationship with said second disk fixed to said driving second shaft, and to thereby maintain said second gear wheel connected to said third cylindrical housing of said third clutch means in disengaged relationship with said driving second shaft.

12. The entry apparatus defined in claim 13 wherein said upwardly directed abutments of said sensing arms of said first and said second controlling means and said upright extension of said sensing member of said means for activating and deactivating said first clutch means of said first coupling means are responsive to and cooperably disposed relative to the keyboard of the calculating machine into which said apparatus is incorporated, said keyboard being characterized by: a. a plurality of biased and pivotally mounted transverse levers disposed in corresponding grooves formed in said keyboard, and b. a plurality of translatably supported longitudinal slides disposed in cooperating relationship with said transverse levers, each of said slides being provided on its uppermost edge with a distinctive pattern of slots the slopes thereof cooperating with predetermined ones of said pivotal transverse levers upon depression of corresponding keyboard keys to activate said slide in a rearward direction, a first, second, third and fourth slide thereof each being provided also with a depending projection disposed in restrictive cooperable relationship with said upwardly directed abutments of said sensing arms of said first controlling means, a fifth and sixth slide thereof being provided with a depending projection disposed in restrictive cooperable relationship with said abutments of said sensing arms of said second controlling means, and a seventh slide thereof being provided with a depending projection and companion pivotal arm disposed in restrictive cooperable relationship with said upright extension of said sensing member of said means for activating and deactivating said first Clutch means.

13. The entry apparatus defined in claim 12 wherein: a. said first, second, third and fourth cams of said first controlling means, and said fifth and sixth cams of said second controlling means are each integrally provided with a camming segment and an adjacent follower segment, said camming segments being provided with raised portions of varying circumferential length and said follower segments being provided with corresponding recesses formed therein, the mid-point of each recess being disposed 180* removed from the mid-point of said corresponding raised portion, and b. said cam follower levers corresponding to said cams of said first and said second controlling means are each provided with an upper arcuate prong cooperably associated with said follower segment of its respective cam, and provided also with a lower arcuate prong cooperably associated with said camming segment of its respective cam, the contact of said raised portion of said camming segment against said lower arcuate prong, during said unidirectional rotation of said driven third shaft, being effective to rotate said lever in a counterclockwise direction on said seventh shaft, said counterclockwise rotation thereby elevating its said pivotally connected sensing arm said predetermined minimal distance against said bias of its said associated spring.

14. The entry apparatus defined in claim 13 wherein said elevation of said sensing arms said pre-determined minimal distance is effective: a. to idlingly rotate said sensing arms a minimal counterclockwise distance relative to said associated cam follower levers, when said upwardly directed abutments of said sensing arms are unrestricted by said depending projections of said associated longitudinal slides of said keyboard, as when said slides are located in their forward home positions, and b. to activationally rotate said sensing arms a minimal clockwise distance relative to said associated cam follower levers, when said abutments of said sensing arms are so restricted to said depending projections of said keyboard slides, as when said slides are located in their rearward translated positions, said minimal clockwise rotation of a given one of said sensing arms being effective to rockingly elevate said abbreviated ninth or tenth shaft with which the slot thereof is engaged and to thereby rotate said first or said second latch arm into displaced relationship with said stops of said second or said third hub member of said second or said third clutch means, said displacement resulting in said coupling of said first gear wheel with said driven third shaft or said coupling of said second gear wheel with said driving second shaft, said coupling of said gear wheels continuing for an interval of time as controlled by said first or said second controlling means.

15. The entry apparatus defined in claim 13 wherein said raised portions of said camming segments of said first, said second, said third, said fourth, said fifth and said sixth cams of said first and said second controlling means are staggered relative to the circumference of said driven third shaft to which they are fixed, and wherein said raised portions are of varying circumferential length, said raised portions of said first and said sixth cams extending over 36* of their respective circumferences, said raised portions of said second and said fifth cams extending over 72* of their respective circumferences, said raised portion of said third cam extending over 144* of its respective circumference, and said raised portion of said fourth cam extending over 288* of its respective circumference, said staggering of said raised portions of said first, said second, said third, said fourth, said fifth and said sixth cams being such that their activational influences occur during the first tenth; second and third tenths; fourth, fifth, sixth and seventh tenths; second, third, fourth, fifth, sixth, seventh, eighth and ninth tEnths; eighth and ninth tenths; and tenth tenths rotation, respectively, of said one revolution rotation of said driven third shaft.

16. The entry apparatus defined in claim 14 wherein said frame of said translatable selector carriage comprises: a. a first frame member, b. a second intermediate frame member, c. a third frame member, d. a plate connecting said first, said second and said third frame members, and e. an eleventh shaft connecting said first, said second and said third frame members, said plurality of toothed members being rotatably supported by said first shaft between said second and said third frame members.

17. The entry apparatus defined in claim 16 wherein each of said plurality of toothed members of said selector carriage comprises: a. a webbed portion extending over approximately one half of the circumference of said toothed member, said webbed portion comprising readable numbers 0 through 9, b. a toothed portion comprising ten teeth disposed along the circumference of said toothed member opposite said webbed portion, and c. a slot of predetermined arcuate length formed in said toothed member.

18. The entry apparatus defined in claim 17 wherein said translatable selector carriage additionally comprises: a. a twelfth shaft disposed in parallel spaced-apart relationship with said first shaft, said twelfth shaft freely passing through corresponding apertures formed in said first, said second and said third frame members and extending outwardly in opposite directions from said first and said third frame members to a fixed relationship with a pair of cam followers rotatably supported by said first shaft, b. a thirteenth shaft disposed in parallel relationship with said first and said twelfth shafts, said thirteenth shaft freely passing through corresponding apertures formed in said first, said second and said third frame members and through said slots formed in said toothed members, said thirteenth shaft extending outwardly in opposite directions from said first and said third frame members to a fixed relationship with a pair of cams disposed in cooperating relationship with said pair of cam followers rotatably supported by said first shaft, c. a plurality of intermediate gear wheels rotatably supported by said twelfth shaft between said second and said third frame members, each of said gear wheels being cooperably engaged with a corresponding one of said plurality of toothed members, d. a sleeve rotatably supported by said first shaft between said first and said second frame members, said sleeve having an internal spiral groove corresponding to said spiral groove of said first shaft and having also a forked projection guideably and slideably disposed on said thirteenth shaft, and e. a plurality of ball bearings disposed between said first and said second frame members and jointly housed by said spiral groove of said sleeve and by that portion of said spiral groove of said first shaft transitionally located between said first and said second frame members, said cooperation of said ball bearings, said sleeve and said first and said second frame members being effective, during said rotation of said first shaft in said first direction, to translate said selector carriage a differential distance in an advancing direction suitable for entering a decimal value in said next lower order toothed member or for registering said absence of a value in said one or more orders, and effective, during said rotation of said first shaft in said second direction, to translate said selector carriage in a return direction preparatory to the entry of the most significant digit of a separate and succeeding numeric amount, said translation of said selector carriage in either of said directions being accommodated by the lateral movement of said carriage along said twelfth and said thirteenth shafts.

19. The entry apparatus defined in claim 18 wherein said first gear wheel connected to said secoNd cylindrical housing of said second clutch means is cooperably engaged with a single pinion rotatably supported by an abbreviated fourteenth shaft, said single pinion being individually and successively engageable with toothed members of lower and higher order as said selector carriage is translated in said advancing and said return directions, respectively.

20. The entry apparatus defined in claim 19 wherein: a. said slideable fourth shaft is additionally provided with a first and second actuator fixed thereto in spaced-apart relationship, said first actuator having a pair of slotted and spaced-apart arms disposed in stradding relationship with a fifteenth guide shaft, and said second actuator having a slotted arm engaged with the groove of a grooved roller rotatably carried by said actuator, b. said driven third shaft is additionally provided with a first profiled cam affixed thereto in interposed relationship between said pair of slotted arms of said first actuator, and c. said thirteenth shaft is additionally provided with a second profiled cam affixed thereto outwardly adjacent the leftmost of said pair of cams thereof, said second profiled cam being disposed in cooperating relationship with said grooved roller of said second actuator, said one revolution rotation of said driven third shaft being effective, through the cooperation of said first profiled cam and said first actuator, to translate said fourth shaft a minimal rightward distance and to thereby couple said fourth and said fifth gear wheels for said advancing translation of said selector carriage, and said rotation of said thirteenth shaft being effective, through the cooperation of said second profiled cam and said grooved roller of said second actuator, to translate said fourth shaft a minimal leftward distance and to thereby couple said fourth and said third gear wheels for said return translation of said selector carriage.

21. The entry apparatus defined in claim 20 wherein the depression of either a value key or a zero key of said keyboard is effective to activate said first clutch means and to thereby couple said driven third shaft to said driving second shaft for said one revolution rotation of said third shaft, said cams of said third shaft forming a part of said first controlling means and said cams forming a part of said second controlling means being rendered effective or ineffective to advance one of said toothed members of said selector carriage or to translate said selector carriage in said advancing direction, respectively, according to whether said sensing arms associated with said cams are activationally or idlingly rotated, said sensing arms being activationally rotated when blockably restricted by said depending projections of said associated keyboard slides and being idlingly rotated when unrestricted by said depending projections.

22. The entry apparatus defined in claim 20 wherein the depression of a value key one through nine of said keyboard is initially effective to advance a toothed member of said selector carriage a corresponding rotational distance, through said activation of said abbreviated ninth shaft and said second clutch means, and thereafter effective to translate said selector carriage a one unit distance in said advancing direction through said activation of said abbreviated tenth shaft and said third clutch means.

23. In a calculating machine having means for printing decimal amounts and continuous motive means, an improved entry device for differentially advancing a single digit-entry gear wheel from a one to a nine tooth distance, said device comprising: a. means for coupling said single gear wheel to said continuous motive means, b. separately and collectively operable means for determining the interval of said coupling of said gear wheel and said motive means, said interval being differentially suitable for advancing said gear wheel from said one to said nine tooth distance, said means being characterized by a predetermined number of sets of associated elements that are separately operable in the entry of decimal values 1, 2, 4 and 8, and operable in combination in the entry of decimal values 3, 5, 7 and 9, and c. means for activating said coupling means and said interval-determining means, said entry device by reason of said predetermined number of sets of elements of said interval-determining means being also readily adaptable for entering binary information into said calculating machine, said sets of elements having binary significance in that they correspond to the binary digits 1, 2, 4 and 8.

24. The entry device defined in claim 23 wherein said means for coupling said single gear wheel to said continuous motive means comprises: a. a driving shaft rotationally responsive to said motive means, b. a driven shaft coaxially disposed of said driving shaft, c. a first clutch effective for engageably coupling said driven shaft to said driving shaft for a one revolution rotation therewith, d. means for engaging said first clutch, and e. a second clutch supporting said single gear wheel and effective for engagably coupling said gear wheel to said rotating driven shaft.

25. The entry device defined in claim 24 wherein said interval-determining means comprises: a. a plurality of four cams fixed to said driven shaft intermediate said first and said second clutches, said cams having raised portions of varying circumferential length, said raised portions being staggered relative to the circumference of said driven shaft, b. a plurality of four rotatably supported cam follower levers disposed in cooperating relationship with said plurality of cams, said levers being biased in a first rotational direction by spring means and being activatable in a second rotational direction by said revolution of said driven shaft and said cams, c. a plurality of four sensing arms pivotally connected to said cam follower levers, said sensing arms being rotatable in an idling first and an activational second direction on said cam follower levers, each of said sensing arms being provided with an upwardly directed abutment formed on its frontmost extremity and with a slot formed in its rearmost extremity, and d. means responsive to said activational second direction rotation of said sensing arms on said cam follower levers, said means being effective to engage said second clutch and to hold said clutch engaged during the interval in which any one of said sensing arms is retained in said activationally rotated state by its associated cam.

26. The entry device defined in claim 25 wherein said means for engaging said first clutch comprises: a rotatably supported sensing member having an upright extension formed on its frontmost extremity and a rearmost extension blockably and releaseably associated with said first clutch, said first clutch being disengageably conditioned to uncouple said driven shaft from said driving shaft when blocked by said rearmost extension of said sensing member, and being also engageably conditioned to couple said driven shaft with said driving shaft when released by said sensing member, said sensing member being normally biased in such manner as to engageably release said first clutch.

27. The entry device defined in claim 26 wherein said means for activating said coupling means and said interval-determining means comprises: a. a plurality of depressible keys representing decimal values one through nine, said depressible keys being supported by and associated with said calculating machine, and b. a plurality of five translatably supported slides associated with said depressible keys, four of said slides each having a depending projection cooperably associated with a corresponding one of said four sensing arms and more particularly to said upwardly directed abutment thereof, and a fifth of said slides having a depending projection cooperably associated with said upright extension of said sensIng member, said plurality of slides being biased in their forward home positions wherein said depending projection of said fifth slide assumes a blocking and bias-resisting relationship with said upright extension of said sensing member and wherein said depending projections of said four slides assume a cleared relationship with said upwardly directed abutments of their associated sensing arms, said cleared relationship being effective to produce said idling first direction rotation of said sensing arms on said cam follower levers during said one revolution rotation of said cams, the depression of any one of said depressible keys being cammingly effective to translate said fifth slide in a rearward direction to thereby release said sensing member to the control of its said normal bias and to thereby engageably release said first clutch, said key depression being also cammingly effective to translate at least one of said four slides in a rearward direction to thereby establish a blocking relationship with said abutment of its associated sensing arm, said blocking relationship being effective to produce said activational second direction rotation of said sensing arm during said one revolution rotation of said cams, said activational second direction rotation being effective, through said means for engaging said second clutch and through said second clutch, to couple said gear wheel with said rotating driven shaft for an interval sufficient to advance said gear wheel a rotational distance corresponding to said decimal value of said depressed key.

28. The entry device defined in claim 25 wherein said means for engaging said second clutch and for holding said clutch engaged during said interval in which any one of said sensing arms is retained in its said activationally rotated state by its said associated cam additionally comprises: a. a rotatably supported hub member, said hub member being biased in a first rotational direction, b. a cylindrical housing connected to said hub member for unitary rotation therewith, c. an abbreviated shaft integrally connected to said cylindrical housing, said shaft being engageably associated with said slots formed in the rearmost extremities of said plurality of sensing arms, and d. a latch arm connected to said cylindrical housing and to said abbreviated shaft for unitary rotation therewith, said latch arm being blockably associated with said second clutch as motivated by said bias of said hub member, and being also releaseably associated with said second clutch when said abbreviated shaft and said hub member are rotated in a second direction by said activational second direction rotation of one of said sensing arms, said release of said second clutch being effective to couple said single gear wheel with said rotating driven shaft, said coupling continuing for said interval during which any one of said sensing arms is held in its said activationally rotated state by its associated cam.

29. The entry device defined in claim 25 wherein said plurality of four cams and said associated sensing arms correspond directly to said decimal values 1, 2, 4 and 8, said cams and said sensing arms being separately operable upon depression of corresponding ones of said depressible keys to effectuate a corresponding rotational advancement of said single gear wheel, said cams and said sensing arms being also operable in predetermined combinations upon depression of other of said depressible keys to produce sequential increments of advancement of said gear wheel, the total of said increments corresponding to the value represented by said depressed key.