US3737634A

US3737634A - Digital read-out actuator-indicator for multi-turn shaft-actuated instrumentalities

Info

Publication number: US3737634A
Application number: US00216432A
Authority: US
Inventors: R Gaskill; S Frey
Original assignee: Bourns Inc
Current assignee: Bourns Inc
Priority date: 1972-01-10
Filing date: 1972-01-10
Publication date: 1973-06-05
Anticipated expiration: 1990-06-05
Also published as: FR2167483B1; GB1349814A; JPS4881048A; JPS5541002B2; FR2167483A1; NL7206778A; DE2226319A1

Abstract

A knob-like actuator and indicator device for mechanical connection to a multi-turn instrument such as a potentiometer and effective upon manual rotation of a part thereof to operate the instrument and concurrently through gearing and counting or revolution-indicating mechanism including double-indexing counting or number wheel means, effective to provide at the face end of the device a numerical decimal indication of complete revolutions and fractional revolutions of the instrument shaft from an end or zero position. Use of a double-indexing first counting wheel means reduces by 50 percent the gear ratio between the manually-rotated part of the knob, to thereby reduce by 50 percent gear wear and by a greater amount the tooth-impact at the counter wheel teeth. The first (fastest) number wheel is numbered through two complete zero-through-nine counts and rotates only one-half revolution in registering one-tenth revolution of the instrument shaft. Reduction of the gear ratio permits gross reduction of diameter of an effective actuator-indicator, and permits use of low cost, plastic parts.

Description

United States Patent [191 Gaskill et a1.

[54] DIGITAL READ-OUT ACTUATOR- INDICATOR FOR MULTI-TURN SHAFT-ACTUATED INSTRUMENTALITIES [75] Inventors: Robert E. Gasklll, Santa Ana; Sydney W. Frey, Jr., Upland, both of Calif.

[73] Assignee: Bourns, Inc., Riverside, Calif.

[22] Filed: Jan. 10, 1972 v 211 Appl. No.: 216,432

' [52] US. Cl. ..235/103, 116/115, 338/196 [51] Int. Cl. ..G06m l/22, GOlp 13/00 [58] Field of Search...235/l03l39 R; 116/115-124,

[ 5 6] References Cited UNITED STATES PATENTS 2,777,637 l/1957 Matthew ..235/103 3,065,909 11/1962 Herr ...235/l39 R 3,202,127 8/1965 Struble et a1. 1 16/1 15 Primary Examin erStephen J. Tomsky Attorney-Fritz B. Peterson ['11] 3,737,634 1 June 5,1973

[57] ABSTRACT A knob-like actuator and indicator device for mechanical connection to a multi-turn instrument such as a potentiometer and effective upon manual rotation of a part thereof to operate the instrument and concurrently through gearing and counting or revolution-indicating mechanism including double-indexing counting or number wheel means, effective to provide at the face end of the device a-numerical decimal indication of complete revolutions and fractional revolutions of the instrument shaft from an end or zero position. Use of a double-indexing first counting wheel means reduces by 50 percent the gear ratio between the manually-rotated part of the knob, to thereby reduce by 50 percent gear wear and by a greater amount the tooth-impact at the counter wheel teeth. The first (fastest) number wheel is numbered through two complete zero-through-nine counts and rotates only one-half revolution in registering onetenth revolution of the instrument shaft. Reduction of the gear ratio permits gross reduction of diameter of an effective actuator-indicator, and permits use of low cost, plastic parts.

4 Claims, 12 Drawing Figures PATENTEB Jam 5 m5 sum 1 0r 2 PATENTEDJ'U'H 5W 3.737.634

SHEET 2 or 2 (nuance-mambo NHPIQNQQIQ'INh'EIQWRQ DIGITAL READ-OUT ACTUATOR-INDICATOR FOR MULTI-TURN SIIAFTQACTUATED INSTRUMENTALITIES CROSS-REFERENCED APPLICATION In respect of certain features disclosed herein this disclosure is related to the disclosure contained in the contemporaneously filed disclosure of Sydney W. Frey, Jr., entitled DIGITAL-INDICATING KNOB ENCLOSED MULTI-TURN POTENTIOMETER application Ser. No. 216,520, filed Jan. 10, 1972 and to which reference may be made in respect of details of construction as may be necessary.

BRIEF SUMMARY OF THE INVENTION A. The prior art Several attempts have been made to provide a knob- Iike structure adapted for attachment to a potentiometer shaft extending forwardly through an aperture in a panel, and adapted to concurrently provide a manually-operable knob for rotation of the shaft and an indicator device devised to furnish a numerical indication of the complete revolutions or full turns and fractional portions of a revolution or fractional turns through which the potentiometer shaft has been rotated. Examples of the prior art operator-indicator structures are depicted and described in U. S. Pat. Nos. 2,777,637; 3,067,935; 3,202,127; 2,980,055; 2,805,636; 3,183,885; 3,241,515; and 3,450,091. Generally, such actuator-indicator structures fall into one or another of two classes, namely, multi-dial devices, and digital read-out devices. The latter class is represented by the three first-listed patents, and the dial-type actuatorindicators are represented by the other patents listed.

Dial indicator devices are inherently characterized by requiring an excessive amount of panel space if large enough to provide a desirable degree of resolution of measure of rotation; and, in thosev types in which gears are employed, are characterized by a high degree of gear wearing and consequent short effective lifetimes. Also, it is required that the operator add one indication to another to arrive at a final reading, which adds grossly to likelihood of an error in reading the indicated rotation.

Digital indicator-actuator devices of the prior art comprise a set of counting wheels similar to an odometer, with gearing between the manuallyoperated knob or shell and the first wheel. Since it is desired that the first two indicator wheels indicate decimal fractions of a single revolution of the potentiometer shaft and the third wheel indicates full revolutions of the shaft up to ten, it is general practice to drive the first wheel through ten revolutions during each revolution of the shaft, the first wheel acting to advance the second wheel one decimal digit for each revolution of the first wheel, and similarly the second wheel advancing the third wheel one step or decimal digit for each turn thereof and thus for each full revolution of the knob or shell. It is thus evident that a lO-to-one gear ratio is provided between the knob or shell and the first wheel; and the pinion for the latter is small relative to the knob or shell gear and is subjected to rapid rotation as the knob or shell is rotated. Further, since the first wheel is thus rotated at ten times the rotational speed of the knob, it subjects the indexing tooth of the second wheel to a high impact load when the latter wheel is stepped a digit in either direction. Wear of the first-wheel pinion is thus great in comparison with that of the other gears; and as a consequence it is general practice to make that pinion of metal rather than the considerably less expensive thermoplastic resinous material generally employed for the other gears and the wheels. The single tooth-pair on the first wheel, herein termed the indexing tooth-pair, that at the conclusion of each revolution engages a complementary tooth on the pinion disposed between the first and second number wheels and advances the latterwheel one step or digit, strikes the pinion tooth at a velocity V and transfers energy thereto proportional to KMV wherein K is a dimensional constant and M is an inertial mass constant. The impact energy transfer is thus seen to be dependent upon the square of the rotational speed of the first wheel and hence of that of the knob or shell.

As a consequence of the noted characteristics, digital actuator-indicator devices of the prior art have been large, expensive, or subject to rapid wear and hence of short useful life, or a combination of those undesirable characteristics.

B. The present invention The previously mentioned undesirable features of prior-art knob-like actuator-indicators are eliminated or grossly reduced in the present invention. In accord with the invention the frictional wear of the pinion of the first number wheel is reduced by one-half, and the noted transfer of energy represented by the quantity KMV is reduced by about three-fourths, or such as to be represented by KM (V/Z) by providing two sets of indexing teeth on the first number wheel, a five-to-one ratio of gearing between the actuator knob or sleeve and the first wheel, and revising the numeration on the first number wheel to provide two sets ofdecimal digits each set comprising only the

digits

0, 2, 4, 6 and 8. The five-to-one gearing ratio, replacing the prior art arrangement of l0-to-one ratio, reduces the number of revolutions of the first number wheel to five for each revolution of the knob or actuator, and thus halves the wear of the first-wheel pinion, halves the velocity of rotation of the first wheel relative to the actuator, and thus reduces to one-quarter the impact energy required to be absorbed by the pinions and indexing teeth. Such reductions permit the molding of the first-wheel pinion of thermoplastic material, integral with the number wheel, and hence of greatly reducing the cost-of the first-digit unit of the indicator and to eliminate the cost.

of assembly of pinion and wheel.

The noted advantages are made evident in detail in the preferred and exemplary embodiment of the invention illustrated in the accompanying drawings.

DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded pictorial view to noparticular scale, illustrating the actuating shaft of a panelmounted instrument and the exemplary rotary actuating-indicating apparatus spaced from the shaft to indicate mounting details;

FIG. 2 is an enlarged longitudinal partial sectional view through the apparatus shown in FIG. 1, illustrating a mode of attachment of the actuated instrument on a panel and attachment of the novel actuating-indicating means to the instrument shaft, and further depicting details of gear means;

FIG. 3 is a partial sectional view similar to part of FIG. 2, but with the sectioning at right angles to that of the latter figure, illustrating the arrangement of knoblike actuator, number wheels, and gearing means, with a combination number wheel and pinion shown only partly in section;

FIGS. 4 and 5 are transverse sectional views through the actuator-indicator means, the sections being taken as indicated by directors 4-4 and 5-5, respectively, in FIG. 2;

FIG. 6 is a fragmentary detail sectional view, the sectioning being as indicated by directors 6-6 in FIG. 2;

FIGS. 7, 8, 9, and are sectional views of wheel and gear means and appurtenant structure comprised in the indicator mechanism of the exemplary apparatus shown in FIGS. 1, 2 and 3, the sectioning being as indicated by respective sets of directiors 7-7, 8-8 and 10-10 in FIG. 3, FIG. 8 showing parts in positions different from those depicted in FIG. 10;

FIG. 11 is a pictorial view of a locking step-pinion comprised in the indicator portion of the devices shown in FIGS. 1, 2 and 3; and

FIG. 12 is a tabular representation of the numerals or numerical indicia arranged on the peripheries of the three number-wheels of the indicator means.

DETAILED DESCRIPTION The device of the invention is adapted to be secured to a rotary actuating shaft, such as shaft S (FIG. 2) of a panel-mounted instrument such as a potentiometer I that in this illustrative application is affixed in an aperture A in a panel P by means of a threaded bushing B and a complementary nut N. The shaft S is mounted for rotation in the bushing, and is rotated to actuate the instrument.

In accord with the present invention a mounting plate or bracket 20 is affixed to the panel P by the nut N, optionally with a lock washer W. The bracket is punched to provide a rearwardly-extending locking lug 20! that is dimensioned for reception in an auxiliary hole H formed in the panel P, whereby the bracket is preshaped as a deformed washer, and is provided with a pair of outwardly extending ears 20k as shown in FIG. 1. The actuator-indicator comprises a stationary internal gear 22 whose rear annular flange face 22f is interrupted by a pair of recesses 22r (FIG. 6) into which the ears 20k of bracket 20 are received. At its forward end gear 22 is formed with an annular series of internal gear teeth 22r (FIG. 2), and intermediate its ends is formed with an annular bearing surface 22b, that is seated on an annular carrier presently described.

The indicator-actuator further comprises a rotary planet-gear cage or carrier, herein called a planet carrier, denoted generally by number 24 (FIGS. 2 and 4). The planet carrier comprises an inner metallic sleeve 24s to which the principal body of the carrier is securely affixed as by molded-in flutes, knurling or the like. The sleeve 24s is bored and tapped for reception of a set screw 24c that is disposed for tight engagment with the instrument shaft S when turned in, as indicated in FIG. 2. Thus the planet carrier is adapted to communicate or transfer applied torque to a shaft S to rotate the latter to actuate or adjust the instrument I. A rearvented from rotation on the bushing. The bracket is and carries in the groove a resilient C-ring retainer 24r that serves to retain the stationary gear 22 on the planet carrier.

The planet carrier 24 is longitudinally triply bored as indicated at 24h in FIGS. 2, 4 and 5, and carries in the three bores respective double-ended planet gears 26. The opposed sets of gear teeth of the planet gears are preferably identical, as shown. Those on the rearward ends of the planets are complementary with the teeh 22r of stationary gear 22 and mesh with the latter. As indicated in FIG. 1, the planet carrier presents a generally cylindrical exterior surface that forms the rearward part of a longer surface adapted to be manually gripped for manual application of torque for rotating shaft S. An extension of the surface is provided by an internally-stepped cylindrical shell 28 the configuration of which is indicated in FIG. 2, and the front cylindrical end of which is closed by a transparent lens 30. Shell 28 encloses the indicator mechanism of the actuatorindicator device, and is adapted, following assembly of the indicator, to be secured to the planet carrier at an annular stepped juncture 28j (FIG. 2). The juncture is formed by two sets of coactive annular radial faces and a pair of cylindrical coactive faces, all of which are close-fitting and adapted to be adhesively united or ultrasonically bonded to form an integral unit of the shell and planet-carrier.

The digital indicator structure comprises a circular support 32 (FIGS. 2 and 3) comprising an internal series of gear teeth 32g meshing with the forward gearends of the planet gears 26 and having an exterior cylindrical bearing surface 32b complementary to the interior cylindrical surfaces of shell 28 and the forward annular lip of planet carrier 24, as indicated in FIG. 2. Thus the shell 28 and its unitary extension formed by the planet carrier are rotatable on the bearing surface 32b. When shell 28 and the planet carrier are rotated to rotate shaft S to adjust or actuate instrument I, the planet gears 26 are carried around in their common orbit, and, due to engagement of the rear sets of teeth of the planet gears with the internal gear teeth 22: of the stationary gear 22, the planet gears are forced to rotate about their respective axes. Thus as the shell rotates, axial rotation of the planet gears forces relative rotation of the support 32 equal to, and opposite in direction'to, the shell 28. Thus the support 32 is forced to remain stationary relative to panel P as shaft S is rotated by the shell and the planet carrier. The support 32 is utilized to support the operating parts of the revolution-counting and digital indicating means enclosed within the rotating shell rearward of the transparent lens 30.

The support 32 is formed with two sets of forwardlyextending pillars or pedestals 32p shaped to provide a pair of saddles or

seats

32s and 32s (FIG. 3) in which are seated a hub 38h of a first number wheel 38 presently to be described, and a shaft or spindle 34. A cir cular frame 36 (FIG. 2) is mounted on the forward ends of the noted pedestals 32p and isfenestrated to provide a window 36w (FIG. 1) through which numerical and other indicia may be viewed. The frame preferably is secured to the support 32 by means of pins such as 32a (FIG. 2) formed on the pedestals and tightly fitting in complementary holes in frame 36, without aid from adhesive; but other equivalent means of properly positioning the frame and window may be used.

Mounted on, and carrying one end of spindle 34 (FIG. 3), is the aforementioned combined first drive pinion and number wheel 38 the outer end of which is formed as a pinion 38p. Both hub 38h and the pinion portions of wheel 38 are received in seat 32s. The end of spindle 34 opposite from pinion 38p seats snugly in the saddle or seat 32s, and thus the spindle is retained in a stable attitude, and in a mutually-aiding action, stabilizes wheel 38 in a rotational attitude for rotation about the axis of the spindle.

The first number wheel drive pinion, 38p is complementary to and engages the teeth 28g (FIGS. 2 and3) of a rearwardly-facing driving gear formed around an inner face of shell 28. Thus rotation of shell 28 causes 7,

rotation of pinion 38p and number wheel 38. In accord with the invention, and differing from the conventional practice followed in prior-art counters, the ratio of the number of teeth 28g to the number of teeth in pinion 38p is five to one, rather than 10. to one as in conventional practice illustrated, for example, in U.S. Pat. No.

2,777,637. Thus the first number wheel turns only five revolutions each revolution of shell 28 and shaft S. Conventionally, as in a IO-tum potentiometer or instrument such as indicated at I, the first number wheel is employed to indicate hundredths of a shaft revolution, the second number wheel of a series indicating tenths of a shaft revolution, and the third number wheel indicating individual shaft revolutions from zero to 10. Additional number wheels, such as a fourth, etc., are sometimes used. In the present invention, since the ratio of revolutions'of the shaft S to revolutions of number wheel 38 is only five to one, resulting in only five revolutions of the wheel 38 to each revolution of Shaft 8, each half revolution of that number wheel encompasses ten hundredths of a revolution of the shaft. Accordingly, the numerical indicia on wheel 38 are devised to indicate ten one-hundredths of one shaft revolution on each half of the peripheral face of the wheel. Such indicia are indicated in strip form in the righthand column in FIG. 12, wherein it is noted that the indicia for wheel 38 comprise numerals 2 4 6 8 0 2 4 6 8 0 and thus numerically extend twice 7 through the series of decimal numbers 0 to 10. In the interest of readability in the small-diameter device illustrated, the odd numerals of the decimal series are omitted, and a line substituted, as indicated in the strip at the right in FIG. 12.

As is indicated in FIG. 1, a ledger or index line L is provided on the front face of frame 36, aligned with the center of the window 36w and disposed for registry or alignment with the lines on number wheel 38 as the latter lines appear through the window. As is shown in FIG. 12, other lines, denoted fractions of hundredths of a shaft revolution, are also provided on the first number wheel, as an aid in reading indications provided by the indicator. I

Since each half-revolution of first number wheel 38 represents a full tenth of one revolution of shaft S, provision is made for indexing or stepping of the second number wheel, 40, twice during each complete revolution of the first number wheel. That is accomplished by means presently described.

The indicator portion of the invention as previously noted, includes three digital number wheels, the first and second, denoted 38 and 40 and previously mentioned, and a third, denoted 42 (FIG. 3). The latter two number wheels are formed as rings presenting cylindrical indicia-bearing outer faces and internal faces presenting at one end a continuous set of gear teeth. The

wheels

40 and 42 encircle a hollow carrier 44 (FIG. 3) whose interrupted cylindrical surface provides a bearing on which the number wheels rotatably bear in endto-end stacked relation as is common in revolutioncounting devicesThe carrier is formed with a bore 44b at its inner flanged end, the bore receiving one end of spindle 34 and being supported thereby as indicated in the drawing. The carrier is provided with aligned bores in which is tightly carried with a press fit an index-gear shaft 46 on which are supported for loose rotation first and second indexing gears 48 and 50 of like form and shape (FIG. 11). The index gear 48 comprises a sixtooth output or number wheel-driving section 48a and a six-tooth central input portion 48b, alternate teeth of which are shortened and formed with tooth faces such as 48c and 48d (FIG. 8) configured to engage an interrupted circular inner flange face of a respective number wheel (for example face 38f (FIG. 8) and thereby effective to inhibit rotation of the index gear excepting when an input portion tooth thereof is engaged by an internal tooth formation (such as formation 38d of wheel 38 shown in FIG. 9) on a preceding or driving number wheel. The ends of the intervening teeth are shortened or eliminated, as shown in FIG. 11, to provide clearance for the reduced-diameter inwardlyextending interrupted flange portion of the engaged number wheel. For example, note 'the flange 38f of wheel 38 in FIG. 8, or the similar flange of wheel 40 in FIG. 10, which flanges are interrupted at 382' or 401' to permit rotation of the engaged

index gear

48 or 50 when the latter is driven by a driving tooth formation.

The first number wheel, 38, is formed or provided with a pair of oppositely disposed driving tooth formations 38d, as shown in FIG. 9. The space between the two teeth of the driving tooth formation is in each instance aligned with a respective interruption 38i, (FIG. 8), whereby as a tooth formation 38d engages successive driven portion teeth of index gear 48, the locking portion of the tooth of gear 48 is permitted to rotate, as indicated in FIGS. 8 and 10. When the first index gear, 48, is thus rotated one step (two teeth) by a driving tooth formation of the first number wheel, the driving tooth portion of the index gear advances the second number wheel one tenth of one revolution, there being twenty teeth such as 402 (FIG. 9) on the interior of the driven end of number wheel 40.

It is made evident in the preceding description that as the knob comprising shell 28 and carrier 24 is rotated to rotate shaft S of instrument I, the internal gear comprising teeth 28g in shell 28 concurrently rotates pinion 38p of the first number wheel 38 at a rotational rate five times that of Shaft S, and that the number wheel38 presents to view, insuccessive order, two series of decimal digits during each revolution of the number wheeland hence presents to view, during each complete revolution of shaft S, 10 serial representations of the decimal digits from 0 through 9, whereby the first number wheel accurately presents indications of hundredths of a revolution of shaft S. Also it is evident that by use of inter-digit marks or lines on the number wheel as shown in FIG. 12, fractional portions of hundredths of a revolution of shaft S are accurately presented to view within the margins of window 36w. Further, it is evident that each half-revolution of number wheel 38 causes presentation of indications of ten hundredths of a revolution of shaft S. Further, since second number wheel 40 is stepped two tooth spaces (one-tenth revolution) each time the first number wheel completes a half-revolution, the second number wheel presents indications of tenths of a revolution of shaft S.

The second number wheel 40 is formed with but one driving tooth formation, as indicated in FIG. 10, and hence is effective to rotate the second index gear 50 two tooth spaces for each revolution of wheel 40, thus advancing the third number wheel two tooth spaces or one tenth revolution. Thus the third number wheel is rotated one revolution each 10 revolutions of second number wheel 40 and ten revolutions of shaft S. Hence it is evident that with decimal indicia applied to

wheels

38, 40 and 42 as indicated in FIG. 12, the third number wheel is effective to present within window 36w an indication of the number of full revolutions of shaft S from an initial or zero position or attitude, while second number wheel 40 similarly presents an indication of the tenths of a single revolution of shaft S beyond the zero position or beyond any complete revolution from zero through nine; and the first number wheel as noted, presents indications of hundredths (or fractional pora tions thereof) of revolution of shaft S beyond any complete tenth of such revolution.

It will be noted that because of the rotation of the first wheel pinion 38p only five turns each revolution of shaft S, the pinion tooth wear is but half that experienced with the 10-to-one gearing utilized in prior-art digital indicators incorporated in shaft-actuating knobs, and that the necessary application of torque is reduced by approximately one-half. Further, since the speed or velocity at which driving teeth in the gearing engage driven teeth is reduced to one-half that experienced in the noted prior-art devices, the impact-loads applied to driven teeth by driving teeth of the gearing in advancing a number wheel a step are reduced to approximately one-fourth those applied in the prior-art devices, all other operating conditions being the same. Thus it is evident that the invention provides great reduction in wearing of the parts and consequent increase in useful life of the device and exceptional reduction in likelihood of breaking or jamming of parts of the indicator gearing. Further, since the number of teeth in the first number wheel driving pinion is doubled, relative to the number of teeth in the prior-art indicator devices, the diameter of the noted pinion, (38p) is doubled. Accordingly, pinion teeth of good mechanical design can be used even when a primary knob gear of less than one inch diameter is used. The latter is made essential when knobs of diameter no greater than 1 inch are required in reducing panel space allotted for operating instruments, as is present practice. It should be noted that with a seven-eights inch knob diameter, the ten-toone gearing ratio used in the prior-art would require a very expensive metal primary knob gear and first wheel pinion. Even with the prior-art knobs of one and one-half inch diameter, or larger, the first number wheel pinion was required to be of metal to withstand the wear and applied stresses. As illustrated in US. Pat. No. 2,777,637, such arrangements required two or three parts for the first number wheel and pinion, and involved expensive assembly operations. In contradistinction, by the present invention the first number wheel and its hub and pinion are inexpensively produced as a single integral part of molded selflubricating or low-friction thermoplastic material. Thus the invention permits production of successful actuator-indicators of much smaller diameter than was feasible in the prior art, with concurrent reduction in cost and increased longevity. Hence it is evident that the aforementioned objects of the invention have been fully attained.

Having described in detail a preferred embodiment of the invention, we claim:

1. A revolution-indicating device adapted to be connected to a multi-turn potentiometer or other adjustable device, said device comprising:

first means, including a rotary structure adapted for internal connection to an adjustable portion of an adjustable device and presenting an external surface adapted for manual application of torque to rotate the adjustable portion on a one-to-one ratio, said first means including an internal primary driving gear means having a defined axis for transmitting torque for driving an indicator device and including internally a rotary bearing surface coaxial with said axis;

second means, including an indicator device having support means and a driven pinion supported by the support means in mesh with said primary driving gear means, said indicator device including at least first and second indicia-bearing number wheels and indexing gear means therebetween supported by said support means and arranged to be driven by torque applied to said driven pinion by said primary driving gear means incident to rotation of said rotary structure, said driven pinion and said first number wheel being directly connected each to the other and the gear ratio of said primary driving gear means to said driven pinion being fiveto-one whereby said driven pinion rotates five revolutions per revolution of the primary driving gear means, said first number wheel including first and second diametrically opposite indexing gear driving tooth formations operative to step said indexing gear means twice during each revolution of said first number wheel, each of said steps being effective to step said second wheel one-tenth of a revolution; and third means, for maintaining said support means stationary during rotation of said rotary structure about said axis.

2. A revolution-indicating device according to claim I, in. which said first number wheel bears respective series of indicia of decimal digits comprised in the numbers zero through nine on each half of its periphery whereby to indicate rotation of said rotary structure through one-tenth of a revolution duringeach half revolution of said first number wheel.

3. A device according to claim 1, in which said third means includes stationary means arranged to be prevented from rotation about said axis and a set of planet gear means carried by said rotary structure in an orbital path around said axis, and in which said stationary means includes a stationary gear means meshed with said planet gear means and thereby causing rotation of said planet gear means about their respective axes incident to rotation of said rotary structure about said axis, and in which said support means comprises a gear meshed with said planet gear means, whereby said support means is caused to remain stationary relative to said stationary means during rotation of said rotary structure.

4. A shaft-actuating and revolution-indicating device adapted to be attached to the rotary actuating shaft of a multi-turn potentiometer or the like the shaft of which extends through an aperture in a mounting panel, said device comprising:

first means, including a rotary structure adapted for internal fixed attachment to an end of a shaft and defining an axis and presenting an external surface adapted for manual application of torque to actuate the shaft on a drive ratio of one-to-one, said first means including an internal primary driving gear means disposed coaxial with said defined axis for transmitting torque for driving an indicator device and including internally a rotary bearing surface coaxial with said axis;

second means, including an indicator device having support means and a driven pinion supported by the support means in mesh with said primary driving gear, said indicator device including at least first and second indicia bearing number wheels and indexing gear means therebetween supported by said support means and arranged to be driven by torque applied to said driven pinion by said primary driving gear means incident to rotation of said rotary structure, said driven pinion and said first number wheel being directly connected each to the other and the gear ratio of said primary driving gear means to said driven pinion being fiveto-one whereby said driven pinion rotates five revolutions per revolution of the primary driving gear means, said first number wheel including first and second diametrically opposite indexing gear driving tooth formations operative to step said indexing gear means twice during each revolution of said first number wheel, each of said steps being effective to step said second wheel one-tenth of a revolution; and

third means, for maintaining said support means stationary relative to the mounting panel during rotation of said rotary structure about said axis.

Claims

1. A revolution-indicating device adapted to be connected to a multi-turn potentiometer or other adjustable device, said device comprising: first means, including a rotary structure adapted for internal connection to an adjustable portion of an adjustable device and presenting an external surface adapted for manual application of torque to rotate the adjustable portion on a one-to-one ratio, said first means including an internal primary driving gear means having a defined axis for transmitting torque for driving an indicator device and including internally a rotary bearing surface coaxial with said axis; second means, including an indicator device having support means and a driven pinion supported by the support means in mesh with said primary driving gear means, said indicator device including at least first and second indicia-bearing number wheels and indexing gear means therebetween supported by said support means and arranged to be driven by torque applied to said driven pinion by said primary driving gear means incident To rotation of said rotary structure, said driven pinion and said first number wheel being directly connected each to the other and the gear ratio of said primary driving gear means to said driven pinion being five-to-one whereby said driven pinion rotates five revolutions per revolution of the primary driving gear means, said first number wheel including first and second diametrically opposite indexing gear driving tooth formations operative to step said indexing gear means twice during each revolution of said first number wheel, each of said steps being effective to step said second wheel one-tenth of a revolution; and third means, for maintaining said support means stationary during rotation of said rotary structure about said axis.

2. A revolution-indicating device according to claim 1, in which said first number wheel bears respective series of indicia of decimal digits comprised in the numbers zero through nine on each half of its periphery whereby to indicate rotation of said rotary structure through one-tenth of a revolution during each half revolution of said first number wheel.

4. A shaft-actuating and revolution-indicating device adapted to be attached to the rotary actuating shaft of a multi-turn potentiometer or the like the shaft of which extends through an aperture in a mounting panel, said device comprising: first means, including a rotary structure adapted for internal fixed attachment to an end of a shaft and defining an axis and presenting an external surface adapted for manual application of torque to actuate the shaft on a drive ratio of one-to-one, said first means including an internal primary driving gear means disposed coaxial with said defined axis for transmitting torque for driving an indicator device and including internally a rotary bearing surface coaxial with said axis; second means, including an indicator device having support means and a driven pinion supported by the support means in mesh with said primary driving gear, said indicator device including at least first and second indicia bearing number wheels and indexing gear means therebetween supported by said support means and arranged to be driven by torque applied to said driven pinion by said primary driving gear means incident to rotation of said rotary structure, said driven pinion and said first number wheel being directly connected each to the other and the gear ratio of said primary driving gear means to said driven pinion being five-to-one whereby said driven pinion rotates five revolutions per revolution of the primary driving gear means, said first number wheel including first and second diametrically opposite indexing gear driving tooth formations operative to step said indexing gear means twice during each revolution of said first number wheel, each of said steps being effective to step said second wheel one-tenth of a revolution; and third means, for maintaining said support means stationary relative to the mounting panel during rotation of said rotary structure about said axis.