Historical Document · 1957
US Patent 2,797,047: Calculator (O. Lehre, the Dial-A-Matic)
Lehre's Dial-A-Matic, granted 25 June 1957.
Historical Document · 1957
Lehre's Dial-A-Matic, granted 25 June 1957.
June 25, 1957 O. EHRE 2,797,047 CALCULATOR Filed April 30, 1954 2 Sheets-Sheet I N WVVVVVVVVVVVVVVVVVVVVY ;--«^- N gzzzzzzzzzzzzz!| 24–-.!!!, INVENTOR. o77o AAA/ea. By f2loga- 2. a77OAAVEys. June 25, 1957 O. LEHRE 2,797,047 CALCULATOR Filed April 30, 1954 2 Sheets-Sheet 2 INVENTOR O77O AAAAA BY ?óes.-, 19-yr. <<a /977OAweys United States Patent Office 2,797,047 CALCULATOR Otto Lehre, Springfield, N.J., assignor to Stering Plastics Co., Union, N.J., a corporation of New Jersey Application April 30, 1954, Seria No. 426,807 2,797,047 Patented June 25, 1957 2 said one dial upon each complete revolution of said other dial. Thus the successive dials of the series may accu mulate digits in orders of units, tens, hundreds, etc. and digits of any order may be added or subtracted and prop erly accumulated by the rotation of the corresponding dial. In order to assure the proper degree of angular dis placement of one dial in response to rotation of another, control means are provided which include a rockably 0 mounted retainer or pawl having one end formed to en 6 Claims. (C. 235-74) gage between adjacent indexing elements on the trans mission gear and another end that coacts with a projec tion or projections on said other dial of any two adjacent dials. The projection or projections have a fixed angu The present invention relates to improvements in cal 15 lar relation to the abutment on the same dial, and the culators, particularly of the type having dials which are several parts are so related that each action of the abut manipulated to introduce the problem into the calculator ment to displace the coacting transmission gear is ac and then indicate the result of the calculation. companied by a rocking of the pawl out of the path of It is an object of the invention to provide a calculator the indexing elements on that gear yet is followed by of the described character made up of a relatively small 20 positive movement of the pawl into an active position in number of parts which are easily assembled together to which it blocks further angular displacement of the trans form a simple and compact structure capable of accu mission gear. rate addition and subtraction. Another feature of the invention resides in the provision Another object is to provide a calculator of the de of a single spring means cooperating with the dials in two scribed character capable of performing calculations in 25 adjacent digit assemblies of a calculator of the kind de volving a plurality of digits, and wherein identical and scribed above and preventing inadvertent rotation of said cooperating assemblies of parts are included for each of dials from registering positions. the digits, with such parts being simple in configuration The foregoing, and other objects, features and advan as to be susceptible of manufacture from molded, or tages of the invention, will be apparent in the following otherwise formed, plastic resin, thereby to make feasible 30 detailed description of an illustrative embodiment pre the inexpensive, mass production of the calculator. sented by way of example and to be read in connection Still another object is to provide a calculator of the with the accompanying drawings forming a part hereof, described character having means embodied therein to and wherein: prevent over-running or incorrect indexing of the succes 1 is a top pian view of a calculator embodying sive dials during accumulative angular displacement of 35 theFig. present invention, with a portion of the casing thereof the dials in response to rotation of the preceding dial. removed to show the internal mechanism; A further object is to provide a calculator of the de being Fig. 2 is a fragmentary, enlarged view of a portion of scribed character which is so simple and compact in con Fig. 1 with one of the dials included in the mechanism struction as to make possible the mounting thereof in the being partly broken away and in section to illustrate the cover of a box, for example, for pencils and the like. 40 cooperation thereof with other parts of the mechanism In accordance with the present invention, the possibility and with a pawl included in the mechanism being shown of inexpensively manufacturing and assembling the vari in broken lines in its released position; ous parts of the calculator is realized by providing an Fig. 3 is a longitudinal, sectional view taken along the elongated, relatively flat casing including a top having line 3-3 of Fig. 2; suitable openings through which the dials can be ma 45 Fig. 4 is a longitudinal, sectional view taken along the nipulated and the totals viewed and a bottom having pro line 4-4 of Fig. 2; jections extending perpendicular thereto and on which all Fig. 5 is a bottom plan view of one of the dials included parts of the calculator, other than the casing, are mounted in the calculator embodying the invention; from above, thereby facilitating the formation of the cas Fig. 6 is a side elevational view of the dial of Fig. 5; ing from molded, or otherwise formed, plastic resin and 50 Fig. 7 is a bottom plan view of a transmission gear the assembly of the parts on said projections of the bottom included in the illustrated embodiment of the invention; and prior to closing of the casing by the top thereof. A calculator according to this invention includes a plu Fig. 8 is a side elevational view of the transmission gear rality of independently rotatable dials, each correspond 55 of Fig. 7. Referring to the drawings in detail, and initially to Figs. ing to a digit in the numerical result of a calculation, which are mounted in a common plane with accumulat 1 to 4, inclusive, a calculator embodying the present in ing means co-acting between adjacent dials to effect ac vention is there illustrated and generally identified by the cumulative angular displacement of one of the adjacent reference numeral 10. Calculator 10 includes a hollow, dials in response to rotation of the other. The accu 60 elongated and relatively flat casing defined by a top mulating means include a transmission gear rotatably wall 12, bottom wall 13 and side wall 14 maintaining the mounted between the axes of any two adjacent dials, at walls 12 and 3 in spaced apart relationship. least one of which has a gear mounted thereon and in The calculator 0 illustrated in Fig. 1 is intended for mesh with said transmission gear so that the one dial the performance of calculations involving numbers of no and the transmission gear rotate together. The trans 65 more than four digits, but it is to be understood that mission gear carries a circularly arranged series of spaced indexing elements which project into the path of rotation of a driving abutment on the other of the adjacent dials, so that the abutment engages one of the indexing ele calculators for more or less digits may be constructed in accordance with the invention. The calculator 10 includes a manipulating and indicating dial for each of the digits, and these dials are generally identified by the ments to angularly displace the transmission gear and 70 reference numerals 15, 15a, 15b and 15c, respectively, 2,797,047 r r The several dials are mounted in a row within casing 11 at locations which are spaced apart longitudinally for rotation about respective stub shafts 16 projecting from bottom wall 3. Each of the dials includes a substantially circular disc cutor otherwise formed on the upper surface thereof So as to be selectively visible through a related viewing open 17 (Figs. 2 and 5) having ten total figures, 0 to 9, printed, 4. teeth, and a driving abutment 27 depends from disc 17 of each of the dials to engage the pins 26 of the trans mission gear disposed to the left of the related dial, as viewed in Figs. 1, 2, 3 and 4 of the drawings. Thus, the driving abutment 27 of dial 15 is engageable with pins 26 of transmission gear 24, the driving abutment of dial 15a is engageable with pins 26 of transmission gear 24a, and the driving abutment of dial 15b is engageable with pins 26 of transmission gear 24b. Preferably, as shown ing or window 18 formed in upper wall i2 of the casing 10 in Fig. 2, the pins 26 are disposed adjacent the bases of (Fig. 1). The upper surface of each disc 17 is also pro the teeth of the related transmission gear, while the driv vided with a circularly arranged series often Spaced apart ing abutment 27 terminates, at its inner end, at the ad pockets or recesses 19 which are preferably disposed dendum circle of the gear 23 of the related dial so as to radially inward with respect to the numerals 0 to 9 and avoid contact with the pins 26 of the transmission gear which register with, and are accessible through, a related 15 meshing with the gear 23 of the related dial. substantially circular slot 20 formed in top wall 12 of the In order to yieldably hold the several dials against in casing. A neck or portion 21 extends radially across advertent angular displacement from positions wherein each slot 20 to support the central portion 22 of the top selected ones the numerals on the top surfaces of the wall encircled by slot 20 and also to serve as a stop for related discs of 17 are exposed at the openings 18 in top an operating stylus or pencil inserted in a selected one of 20 wall 12, spring detents 28 and 28a are mounted within the pockets 19 for effecting rotation of the dial. The casing 11 and are engageable with gears 23 of the dials. neck or stop 21 preferably is as wide as the distance In the illustrated embodiment of the invention, spring de between the successive pockets 9, and the numerals 0 tent 28 cooperates with gears 23 of the dials 15 and 15a to 9 on the upper surface of disc 17 are circumferentially while spring detent 28a cooperates with the gears 23 of disposed relative to pockets 19 so that a selected one of 25 dials 15b and 15c. As seen in Fig. 2, each of spring de the numerals will register with the opening 18 when a tents 28 and 23a includes an elongated strip of spring stylus or pencil engaged in a related one of pockets 19 metal interlaced between a central post 29 and two lat comes into contact with one side or the other of stop 21. eral posts 30 spaced from the central post, said posts Addition and subtraction numerals 0 to 9 are printed, extending from bottom 3 of the casing to support the cut or otherwise formed on the upper Surface of top wall 30 spring detent, while the opposite ends of the spring de 12 along each of the circular slots 20. The addition tents are provided with bent noses 31 engageable between numerals are placed consecutively anti-clockwise along the successive teeth of the adjacent gears 23 and urged the outer edge of the related slot 20 and starting from the radially inward by the resilience of the detent toward the stop 21; while the subtraction numerals are placed con 35 centers of rotation of the gears. Thus, at any time, the secutively clockwise on the top wall portion 22 along the detents 28 and 28a are effective to yieldably hold the re inner edge of the related slot 20 and also starting from lated dials in angular positions wherein one of the nu merals on the top surface of each of the dials will be the stop 21. In order to provide for the accumulative angular dis completely exposed at the related opening 18. placement of each of the dials i5a, 15b and 15c in re 40 In accordance with the present invention, control means sponse to the rotation of the preceding dials 15, 15a and are associated with each of transmission gears 24, 24a 15b, respectively, each of the dials includes a Spur gear and 24b to ensure that contact between the driving abut 23 (Figs. 2, 5 and 6) disposed below disc 7 and prefer ment or accumulating finger 27 of the adjacent dial with ably formed integral with the latter. Transmission gears a pin 26 of the related transmission gear produces an 24, 24a and 24b are disposed between the Successive angular displacement of the latter of only 36 degrees or spaced apart dials and are rotatably mounted on Suitable 45 one-tenth of a revolution. In the illustrated embodiment stub shafts 25 projecting from bottom wall 13 of the cas of the invention, such control of the step-by-step rota ing. The several transmission gears are arranged so that tion of the transmission gears is effected by rockable retainers or pawls 32, 32a and 32b which are respectively gear 24 meshes with gear 23 of dial 15a, gear 24a meshes with gear 23 of dial i5b and gear 245 meshes with gear associated with the transmission gears 24, 24a and 24b. 23 of dial 15c. While the teeth of gears 24, 24a and 24b 50 Each of the pawls is rockably mounted, intermediate pass under the discs i7 of dials 15, 15a and 5b, respec its ends, on a stub shaft 33 projecting upwardly from bottom wall 13 of the casing. At one end, each pawl is tively, it is to be noted that the above enumerated trans provided with a nose 34 having converging or inclined mission gears do not mesh with the gears 23 of the dials side edges and adapted to engage between successive disposed to the right thereof, as viewed in Figs. 1, 2, 3 and 4 of the drawings. 55 pins 26 on the related transmission gear. Pawls 32, 32a and 32b are respectively actuated by dials 15, 15a Each of dial gears 23 and transmission gears 24, 24a and 15b, and such actuation is achieved by a follower and 24b (Figs. 2, 5 and 7) preferably has ten teeth, and portion 35, at the end of each pawl remote from nose the several dials and transmission gears carry cooperat 34, engageable by projections 36, 37, 38 and 39 extend ing members effective to produce the angular displace ment of the transmission gear and of the dial driven 60 ing from the periphery of the dial to the right, as viewed in the drawings, of the related transmission gear. As thereby through one-tenth of a revolution, that is, through seen in Fig. 2, cam-like projections 36 and 37 are adja an angle of 36 degrees, in response to the rotation of the cent to each other and projections 38 and 39 are also dial disposed to the right, as viewed in the drawings, adjacent to each other but spaced circumferentially from through a complete revolution. Thus, the rotation of dial 15 through a complete revolution is effective to produce 65 the projections 36 and 37 thereby to provide a recess a 36 degree displacement of the dial 5a; rotation of dial 40 between the projections 37 and 38. The projections i5a through a complete revolution is effective to produce 36 and 37 are operative to actuate the related pawl 32, a 36 degree angular displacement of dial 15b; and rota 32a or 32b during rotation of the related dial in the tion of 5b through a complete revolution is effective to direction for addition, that is, during clockwise rotation produce a 36 degree angular displacement of dial 15c. 70 of the dial, while the projections 38 and 39 actuate the In order to produce such accumulative angular displace related pawl during rotation of the dial in the direction ment of the dials in response to rotation of the preced for subtraction, that is, during counter-clockwise rotation. ing dials, each of the transmission gears 24, 24a and 24b The projections 36, 37, 38 and 39 are arranged on the is formed with a circularly arranged series of pins 26 pro periphery of the dial so that during engagement between jecting upwardly therefrom in radial alignment with the 5. the abutment 27-and one of the pins 26 of an adjacent 2,797,04? 5 6 transmission gear, radially opening recess 40 is registered 8 and 9, respectively, at the related openings 18 of the with follower portion 35 of the related pawl, to permit top wall. Then, dial 15b is further manipulated, in the movement of the follower portion radially inward toward clockwise direction, by inserting the stylus or pencil in the axis of rotation of the dial and corresponding radially the pocket 19 thereof registered with the numeral 2 at outward movement of the nose 34 away from the axis of 5 the outside of the related circular slot and rotating the rotation of the transmission gear. dial until the pencil or stylus again contacts stop 21. Normally, pawls 32, 32a and 32b are disposed as Similarly, dials 15a and 15 are again manipulated, in shown in Figs. 1 and 2, with the noses 34 thereof posi the clockwise direction through angular displacements tioned between two successive pins 26 on the related trans from the outside numerals 5 and 2 of their respective mission gear thereby to position the latter and the dial O circular slots to the respective stops 21, corresponding to having the gear 23 with which the transmission gear is the addition of 52 to the preceding total, whereupon the in mesh. However, when the transmission gear is angu numbers exposed at the several windows 18 give the final larly displaced by contact of the driving abutment 27 of total of 1041. the dial to the right thereof, as viewed in Figs. 1 and 2, If, for example, it is then desired to subtract 333 from one or the other of the pins 26 between which nose 34 5 the above total of 1041, a pencil or stylus is engaged in engages rides against the confronting inclined side edge the pocket 19 of each of the dials 15b, 15a and 15 in of nose 34 and rocks the pawl in the clockwise direction radial registration with the numeral. 3 of the series of to the position shown in broken lines on Fig. 2 and there numbers extending along the inside edge of the related identified by the reference numeral 32'. Thus, nose 34 of circular slot 20, and the several dials are then rotated the pawl is displaced radially out of the path of travel of 20 in the counter-clockwise direction until the pencil or the pins 26 to permit angular displacement of the trans stylus comes into contact with stop 21. Such counter mission gear, and during such angular displacement of clockwise rotation of the dials 15b, 5a and 15 causes the transmission gear, follower portion 35 of the pawl angular displacement of dial 15c to a position in which engages in the outwardly opening recess 40 at the pe the numeral 0 thereon is exposed at the related opening riphery of the dial. As soon as the transmission gear has 25 18, while the numerals 7, 0 and 8 of the dials 15b, 15a been angularly displaced to an extent sufficient to bring and 15, respectively, are exposed at the related openings the pin 26, mentioned above as riding against the inclined or windows 18. Thus, the described calculating device side edge, past the apex of nose 34, one or the other of can be employed to obtain the solutions to problems of the cam-like projections 37 or 38, depending upon the addition and subtraction wherein the result does not ex direction or rotation of the dial, strikes against follower 30 ceed 9,999. It is apparent that the solutions to problems. portion 35 to displace the latter radially outward with having greater numerical results can be obtained merely respect to the axis of rotation of the dial and thereby by employing a calculating device having a suitably rocks the associated pawl in the counter-clockwise direc larger number of dials and associated accumulating tion, as viewed in Fig. 2, to at least partially introduce mechanism arranged successively in the manner described nose 34 of the pawl between the next successive pins 26 above and illustrated in the drawings. on the transmission gear for preventing over-running or From the foregoing, it is apparent that a calculator em jumping of the latter. Further rotation of the dial brings bodying the present invention includes a casing, an indi either the projection 36 or the projection 39, depending cating and manipulating dial for each digit of the nu upon the direction of rotation of the dial, into engage merals involved in a calculation, a detent spring 28 for ment with the follower portion 35 of the related pawl. each pair of dials in the assembly, transmission gears Since the projections 36 and 39 extend radially outward numbering one less than the number of dials in the further than the projections 37 and 38, engagement of assembly and a pawl for each of the transmission gears. the projection 36 or the projection 39 with the follower Thus, the calculator is formed of a casing and assemblies portion 35 produces additional counter-clockwise rock of only four different kinds of parts, the casing and such ing of the pawl thereby to complete movement of the parts, with the exception of the spring detents, being nose 34 radially inward toward the axis of rotation of easily molded or otherwise formed of suitable plastic the related transmission gear to its normal position where resin materials. Further, all of the above mentioned in the converging side edges of nose 34 engage the pins parts are assembled from above on the shafts or parts 26 at the opposite sides of the nose to again positively which are normal to the bottom wall of the casing and position the associated transmission gear and the dial integral with the latter so as to facilitate the inexpensive with which the latter is in mesh. molding of the casing and mass production of the calcu From the foregoing, it is apparent that each of trans lator. mission gears 24, 24a and 24b can be displaced through While a particular embodiment of the invention has only one tenth of a revolution for each complete revolu been described in detail herein and illustrated in the tion of the dial disposed to the right thereof, as viewed accompanying drawings, it is to be understood that the in the drawings, thereby to prevent jumping of inaccurate invention is not limited to that precise embodiment and indexing of the driven dials, that is, excessive angular that various changes and modifications may be effected displacement of the latter and resultant inaccuracies by one skilled in the art, without departing from in the total, when the manipulated dial is quickly rotated herein, the scope or spirit of the invention as defined in the to provide a substantial impact between its driving abut 60 appended claims. ment 27 and the pins of the adjacent transmission gear. What is claimed is: In operating the above described calculator, dials 15, 1. A calculator comprising a plurality of dials rotat i5a, 15b and 15c are manipulated, by engaging a stylus ably mounted in a row and each corresponding to a digit or pencil in pockets 19 exposed at the circular slots 20, in the numerical result of a calculation, accumulating until the numeral 0 on each of the dials is exposed at 65 means co-acting between adjacent dials to effect accumu the related opening 18 of top wall 12 of the casing. In lative angular displacement of one of the adjacent dials. effecting the addition of two numbers, for example, the in response to rotation of the other, said accumulating numbers 789 and 252, a pencil or stylus is engaged in the means including a transmission gear rotatably mounted pocket 19 of dial 15b registering with the numeral 7 of between said adjacent dials, at least one of said adjacent the series appearing on top wall 12 along the outside of 70 dials having a gear mounted thereon, said gear of only one circular slot 20, and dial 15b is rotated, in the clockwise of said dials being in mesh with said transmission gear, direction, until the pencil or stylus strikes against stop said transmission gear having a circularly arranged series 21. Such rotation will expose the numeral 7 on dial of pins projecting therefrom, a driving abutment on said 15b at the related opening or window 18. The dials 5a other dial following a circular path into which said pins and 15 are similarly manipulated to expose the numerals 75 project so that, upon each complete revolution of said 2,797,047 8 7 other dial, said abutment engages one of said pins to drive in its inactive-position and said other dial being rotatable: independently of said pawl when said pawl is in its active the latter out of said circular path thereby to angularly position. . . displace said transmission gear and said one dial, and 4. A calculator comprising a plurality of independently control means acting on said transmission gear and actu rotatable dials mounted in a common plane on spaced ated by Said other dial to limit the angular displacement parallel axes, said dials being rotatable in either, direction, of Said one dial during each complete revolution of said other dial, said control means including a rockably accumulating means co-acting between adjacent dials to effect accumulative angular displacement of one of the mounted pawl having a nose at one end engageable be tween two adjacent pins of said series of pins on the adjacent dials in response to rotation of the other, said related transmission gear to rotationally position the 10 accumulating means including a toothed transmission latter, said nose having inclined side edges so that said gear rotatably mounted between the axes of said adjacent nose can be moved radially out of the path of said pins dials, at least one of said adjacent dials having a toothed by riding of the pins against said side edges when said gear mounted thereon, said toothed gear of only one of transmission gear is angularly displaced through the ac said dials being in mesh with said transmission gear, said gear having a circularly arranged series of tion of Said driving abutment on one of said pins, and 15 transmission. Spaced indexing elements thereon, a driving abutment on cam-like projections on the periphery of said other dial the other of said adjacent dials, said indexing elements engageable with said pawl to rock the latter in the direc tion again projecting said nose between two adjacent pins projecting into the path of rotation of said abutment so. upon release of said driving abutment from said one pin, that upon each complete rotation of said other dial said: said cam-like projections including a first projection fol 20 abutment engages one of said elements to angularly dis place said transmission gear and cause it to displace said. lowed circumferentially by a second projection, said sec ond projection being radially larger than said first projec one dial in the angular direction of the rotation of said other dial, and control means to limit the angular dis tion so that contact of the latter with said pawl effects placement, said control means including a rockably partial return of said nose to a position projecting between mounted pawl having a nose at one end engageable be said pins thereby to prevent over-running of said trans mission gear, while Subsequent contact of said second pro tween any adjacent two of said elements, said nose having cam surfaces at opposite sides thereof, one of said surfaces jection with the pawl completes the return of said nose to its position between adjacent pins wherein the latter being engaged by an adjacent indexing element upon rota contact said inclined side edges of the nose to positively tion of said transmission gear in either direction to rock 30 said pawl to an inactive position in which said nose is position said transmission gear and said one dial. outside the path of said pins, said other dial having a 2. A calculator according to claim 1; wherein said cam plurality of radial projections thereon and a recess be like projections include two circumferentially spaced apart sets of first and second projections with said first projection of one of said sets circumferentially preceding tween said projections to receive the other end of said upon said other end to rock said pawl so as to return said nose to an active position between an adjacent two of of said dials carrying on its underside an abutment ro tatable into the path of said pins to displace said pins and thus index said transmission gear and said one dial, pawl when said pawl is rocked to inactive position through the second projection of said one set in one direction of a displacement of said transmission gearby said abutment, rotation of said other related dial, while said first projec at least one of said projections being operative upon said tion of the other of said sets circumferentially precedes other end to rock said pawl so as to return said nose to an active position between an adjacent two of said ele the Second projection of said other set in the other direc ments upon the rotation of said other dial in either direc tion of rotation of said other related dial, whereby said tion beyond the point of action of said abutment, whereby pawl is operative to prevent over-running of the related 40 digits may be added by rotating either of said adjacent transmission gear when said other related dial is rotated dials in one direction and may be subtracted by rotating for effecting either addition or subtraction. 3. A calculator comprising a plurality of independently the same in the opposite direction. 5. In a calculator, two circular dials adapted to carry rotatable dials mounted in a common plane on spaced par allel axes, accumulating means co-acting between adjacent digits on one side and mounted in a common plane for dials to effect accumulative angular displacement of one independent rotation on spaced parallel axes, a gear on one of said dials, a rotary transmission gear meshing with of the adjacent dials in response to rotation of the other, said dial gear to rotate therewith, a circular series of said accumulating means including a toothed transmission gear rotatably mounted between the axes of said adjacent Spaced indexing elements on said transmission gear, the dials, at least one of said adjacent dials having a toothed 50 other of said dials carrying an abutment rotatable into gear mounted thereon, said toothed gear of only one of the path of said elements to displace said elements and Said dials being in mesh with said transmission gear, said thus index said transmission gear and said one dial, a transmission gear carrying a circular series of spaced in projection on said other dial in angularly spaced relation to said abutment, and a retainer rockably mounted for dexing elements, a driving abutment on the other of said adjacent dials, said elements projecting into the path of movement between an active position in which one of its rotation of said abutment so that upon each complete ends lies between two adjacent indexing elements on said. transmission gear and an inactive position in which said rotation of said other dial said abutment engages one of said elements to angularly displace said transmission gear one end lies outside the path of elements on said trans and cause it to displace said one dial in the angular direc mission gear and the other end lies in the path of said tion of the rotation of said other dial, and control means 60 projection, said retainer being moved to said inactive position by each indexing movement of said transmission to limit the angular displacement, said control means in cluding a rockably mounted pawl having a nose at one gear and being returned to said active position by said projection upon each complete rotation of said other dial. end engageable between any adjacent two of said ele 6. In a calculator, two circular dials adapted to carry ments, said nose having a cam Surface engaged by an adja digits on one side and mounted in a common plane for cent element upon rotation of said transmission gear to independent rotation on spaced parallel axes, a gear on rock said pawl to an inactive position in which said nose is outside the path of said elements, a radial projection on the underside of one of said dials, a rotary transmission said other dial, the other end of said pawl lying in the gear lying in the plane of and meshing with said dial gear to rotate therewith, a circular series of spaced pins pro path of rotation of said projection when said pawl is in said inactive position, said projection being operative jecting upwardly from said transmission gear, the other said elements following each angular displacement of said transmission gear by said abutment, said one dial being rotatable independently of said pawl when said pawl- is . a radial projection on the periphery of said other dial in angularly spaced relation to said abutment, and a re 2,797,047 tainer having cams at its opposite ends and rockably mounted for movement between an active position in which one of its ends lies between two of said pins and an inactive position in which said one end lies outside the path of said pins and said other end lies in the path of said projection, said retainer being moved to said in active position by each indexing movement of said trans mission gear and being returned to said active position by said projection upon each complete rotation of said other dial. O References Cited in the file of this patent 176,426 349,459 431,365 486,030 491,537 1,764,915 O 2,533,443 2,541,463 UNITED STATES PATENTS Chesterman ----------- Apr. 16, 1876 Shattuck et al. --------- Sept. 21, 1886 Lang ------------------ July 1, 1890 Claudin et al. ---------- Nov. 8, 1892 Durant -------------- Feb. 14, 1893 Vethe --------------- June 17, 1930 Farbman ------------- Dec. 12, 1950 Cummings ----------- Feb. 13, 1951