CA1076843A - Power drive transmission assembly - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

This invention relates to a novel power drive assembly for use with a prime mover. The assembly comprises a rotatably supported first shaft and a rotatably supported second shaft spaced from the first shaft and parallel thereto. A pair of pulleys are provided and the position of the second half portion of the driving pulley relative to the first half portion is fixed by a feedback loop. The driving pulley is utilized as the driven pulley and the driven pulley is utilized as the driving pulley. The prime mover is of the type where rotational speed varies over wave ranges. The feedback loop comprises a sensor which senses the rotational speed of the driven pulley and supplies an output to a comparator means which compares the output of the speed sensor with some reference signal which is related to the desired rotational speed of the driven pulley.
The comparator circuit generates a signal to vary the effective pitch diameter ratio between the driving and the driven pulley which is applied to the power means on the driven pulley so that the output signal from the speed sensor is equal to the reference signal. This produces much more efficient assembly in view of the prior art.

Description

~ 1C?7~;~343 This is a divisional application of patent application serial number 239,932 filed on November 17, 1975.
BACKGROUND OF THE INVENTION
1. Field of the Invention Power drive transmission assembly.

2. Description of the Prior art , In the past, various power operated assemblies have been proposed and used in an attempt to automatically control the pitch diameter ratios of a driving and driven pulley 1~ connected by a V-belt in accordance with ~he rate of rotation imposed on one of the pulleys. Such prior art devices have, in the main, utilized centrifugal means to attempt to accomplish ihis result, but such centrifugal means are effective in but a limited range, and have the disadvantage that they impart a radial imbalance to the system.
The primary purpose in devising the present invention is to supply a power drive transmission assembly which can be automatically or manually control~ed to provide a desired pitch diameter ratio to the driving and driven pulleys 2~ engaged by an endless V-belt. ~his ratio is achieved by varying the pitch diameter of the driving pulley only, and the pitch diameter of the driven pulley automatically varying in accordance therewith due to the spring loaded structure of the driven pulley. The change of the effective pitch diameter o~
~he driving pulley only is accomplished by moving a second portion thereo~ relative to a first portion, which .ncreases or decreases the pitch diameker of the driving pulley~ The pitch diameter of th~

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1~it7689~3 clriven pulley is also controlled by the belt tension, and the magnitude of the spring loading on the second half portion of the dri~ren pulley.
~ major object of the present invention is to provicle a power transmission assen~ly for a pri~e mover, such as an internal combustion engine, which assembly may - be so adjusted that a driving pulley, driven pulley and connectincJ V-belt that form a part thereof are so con-trolled and so cooperate with power means and a sensing device that detect both the rate of rotation and the lat-eral position of a second movable half portion of the driving pulley relative to a half portion that rotates in a fixed-position on the-driving shaft, that the power ~`
means is energized to vary the lateral spacing between the first and second half portions of the driving pulley that a ~esired pitch diameter ratio is achieved between the ~ -dritrins and driven pulleys. As the lateral spacing be-t.7een the first and second ha~f portions of the driving ;
pulley is varied, the tension on the V-belt is increased or ~ecreased, and the effective diameter of the driven pulley is varied by laterally moving a second spring loaded second portion thereof relative to a first portion of ~he ~riven pulley that-is rigidly secured to the driven shaft~
with the ratio between the pitch diameter of the driving and driven pulleys w'nen the ,nvention is operating at all ;~
times has a desirecl relationship to the torque curve of the prime mover.
Another object of the invention is to supply

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1~76~343 po-~er .ransl~ission assembly t'nat ~Jhen in o~eratior ef ~-2C ~S
- an infinite nu~`2er OL variations in the effective pitch ~iameter ratio of the drivin~ ancl dri~ren pulleys without loss o,. power~ is at all ti~es ir. radial balance, requires no radially ntovable parts or wei~hts and in effect uni-formly shifting the pitch diame~er ratio of the driving and driven pulle~s without being dependent on the rate of rotation of the driving pulley.
A further object of t'ne invention is to supply a power transmission assembly that is easily ana con-venientl~ adjustea to a particular torque curve of a particular engine or prime mover, and tihen so adjusted will continue to automatically have a desired relation-ship to the torcfue curve of the engine as ~he driven pul-ley is subjected to varying loads.
Another o~ject of the present invention is tosupply a power drive trans~ission that has a ~road capa-bility to accept a wide variation of engine ~rive speeds, ;~
- horse power, and torque output, and permit greater effi-cienc~ to be obtained ~rom ~he en~ine inasmuch as the po--~er drive assembly does not reGuire the ca,~abilit~ to sense tor~ue ~eing applied to the driven pùlley. , ' ~:~
. Yet another object or the invention i5 to fur nish a po-~er tr~nsmission assembly that permits upward : 25 and downward shifting o~ the pitch diameter ratios. of the ~riving and driven pulleys w~.hout the driving force being disengaged therefrom. ~-.. . .

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``` 1~76843 1 To this end, in one of its aspects, the invention provides a power drive assembly for use in combination with a prime mover comprising: .
a rotatably supported first shaft;
a rotatably supported second shaft spaced from said first shaft and parallel thereto;
a first pulley defined by first and second halves, said first half being rigidly secured to said first shaft and said second half being slidably mounted on said first shaft but 10 non-rotatable relative thereto; ::
a second pulley defined by Eirst and second halves, said first half of said second pulley rigidly secured to said second shaft, and said second half of said second pulley slidably mounted on said second shaft and substantially non-rotatable relative thereto;
an endless V-belt associated with the first and second pulleys; ..
force exerting means that tends to maintain said second half of said second pulle~ in a position relative to said first half thereof such tha~ the effective pi~ch diameter of said second pulley is maximum;
spring means that tends to move said second half of said first pulley to a predetermined maximum spacing relative to said first half thereof; -~
a first means operatively associated with said spring means for moving said second half of said first pulley relative ;:
to said first half therec?f when said first means is energized;
and a second means for energizing said first means in accordance with a predetermined relationship thereby varying the ~ - 4a -~ii76843 1 effective pitch diameter ratio of said first pulley and said second pulley relative to the V-belt, wherein the second means comprises:
(i) a third means for sensin~ the rotational speed of the first shaft, the third means generating a third output whose magnitude is related to said rotational speed, (ii) a reference level, and (iii) a fourth means for compa:ring the difference in the magnitude of the third output and the reference level and 1~ generating a fourth output to energize the first means to move the second half relative to the first half to vary the effective pitch diameter of the first and second pulleys until the third output and the reference level are equal. :~
In another of its aspects, the invention provides, in combination with a prime mover having a driving shaft to which rotational power is transmitted by said prime mover, a power drive assembly operatively associated with sai-d prime ~
mover, said assembly comprising: `
a rotatably supported driven shaft spaced from said 0 driving shaft and parallel thereto;
a driving pulley defined by first and second halves, said first half of said driving pulley rigidly secured to said .-driving shaft, and said second half of said driving pulley slidabl~ `.
mounted on said driving shaft and substantially non-rotatable::
relative thereto; . - ~
a driven pulley defined by first and second halves, -with said first half being rigidly secured to said driven shaft, ~-~
and said second half being slidably mounted on said driven shaft non-rotatable relative thereto;
an endless V-belt associated with the driving pulley and the driven pulleyi ~ - ~b -' - ~76843 - 1 force exerting m~ans that tends to so maintain said second half of said driving pulley in a position relative to said first half thereof such that the effective pitch diameter of said driving pulley is maximum;
spring means that tends to move said second half of said driven pulley to a predetermined maximum spacing relative to said first half.thereof;
a first means operatively associated with said spring means for moving said second half of said driven pulley relative -10 to said first half thereof when said first means is energized ~ :
to vary the effective pitch diameter of said driven pulley;
a second means for energizing said first means in accordance with a predetermined xelationship thereby varying . :
the effective pitch diameter ratio of said driving pulley and said driven pulley relative to the V-belt, wherein the second :.:
means comprises:
(i) a third means for sensi.ng the rotational speed of the .
first shaft, the third means generating a third output whose magnitude is related to said rotational speed, (ii) a reference level, and (iii) a fourth means for comparing the difference in the magnituae o~ the third output and the reference level and ~enerating a fourth output to energize the first means to move the second half relative to the first half to vary the effective pitch diameter of the first and second pulleys until the third output and the reference level are e~ual.
In yet another of its aspects, the invention fuxther provides, in combination with an internal combustion engine having a driving shaft to which rotational power i5 transmitted by said engine in accordance with a predetermined torque curve ~ - 4c -... , ., .. . . : :

~76843 1 inherent to said engine, a power drive assembly operatively associated ~ith said engine for delivering a rotational power out-put that is related to said torque curve, which assembly includes:
a rotatably supported driven shaft spaced from said driving shaft and parallel thereto;
a driving pulley defined by first and second halves, with said first half being rigidly secured to said driving shaft, and said second half being slidably mounted on said driving shaft but nonrotata~le relative thereto;
a driven pulley defined by first and second halves, said first half of said driven pulley rigidly secured to said driven shaft, and said second half of said driven pulley slidably mounted on said driven shaft and substantially nonrotatable relative thereto;
an endless V-belt associated with the driving pulley and the driven pulley;
force-exerting means that tends to so maintain said second half of said driven pulley in a position relative to said first half thereof such that the effective pitch diamet~r of said driven pulley is maximum;
spring means that tends to move said ::~
second half of said driving pulley to a predetermined maximum : spacing relative to said first half thereof;
endless surl~ace-defining means that occupy a fixed position relative to said second half of said driving pulley and ~-rotate concurrently therewith;
a plurality of circumferentially spaced, elongate light-reflecting areas defined on said endless surface defining means, with each of said areas varying longitudinally in width;

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1 means for directing a stationary, continuous first beam of light on~o said areas to be reflected therefrom as a second beam of intermittent pulses which vary in frequency and duration in accordance with the speed of rotat.ion of said driving pulley and the position of said areas longitudinally relative to said first beam; .
a source of electric power;
electric power-operated means operatively associated with said spring means for moving said second half of said driving pulley relative ~o said first half thereof when said power operated means is electrically energized to vary the effective pitch diameter of said driving pulley, and the effective pitch ;~-; dia~e.er of said driven pulley varying in response to variation of the tension on said belt as the effective pitch diameter of - said driving pulley varies; and an electronic circuit energized by said source of electric power, which circuit includes a phototransistor.on which said second beam impinges to render the same conductive, wi~h said circuit including first and second portions that receive pulses of electric energy from said phototransistor and transform the same into first and second voltages that correspond in magnitude t~ the rate at which said areas move past said first beam of light and the duration of time of each of said pulses .~ o~ said second beam of light, with said circuit also including first means for comparing the difference in magnitude between said first and second voltages, and second means responsive to said difference for delivering electric power to said electric power-operated means to move said second half relative to said first half to vary the effective pitch diameters of said driving and driven pulley u.ntil said first and second voltages are equal whereupon said engine operates in a desired relationship to said torque curve in delivering torque to said driven pulley.

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~L~76843 Su~mary of the Invention . .
The poier drive .ransmission assembly is used in conjunction with a prime mover, such as an in-ternal co~ustion enyine or electric motor, t`nat has a kno~7n torque curve. The er.~ine is provide~ t/ith ~ driving S pull~y .nat includes a firs-t half portion that ro~ates in a fixed position relaiive to the drive shaft of the engine. The dri~ring pulley includes a second hal~ por-tion that may move laterally to the first half por-tion on the driven shaft. Power means are provided that ef-fect con~rolled lateral movement of the second half por-tion of the driving pulley relative to ~he fixst half portion thereof.
The dr-ving pulles~ is engaged b~ an endless V-belt, ~.7hich belt also engages a ~riven pulley that is subject to a load of varying magnituae. The driven ~` pulley includes a first halI portion that rotates in -a ~ixed position on the driven sha~t, and a second hal~ -~
portior that is sprins loaded and at all times tends to move toNara he first half portion of the driven pulley.
The power driven iransmission assembly includes an endless rotatable surface .hat rotates with the drLv--ing pulley. The endless surface has a sequence of spaced-light reflecting surfaces or generally triangular shape thereon that are constantly scanned by a photoelectric device. The lig~t reflecting surfaces are of sucil shape that when scanned by the pho,oelectric device first and second electric si5nals are ~enerated that in magnitude are related to the rate a~ w;nicn the driving pulle~ --- . . . . . - .. .. .. ... . :

~ 61343 rotates and the position cf the second ihal portion of t}~e pulle~.
The first and second signals are continuously compared b~r electronic m~ans that at all times tend to maintain them in balance by actuating the power means ~o move the second portion O,c the driving pulley later-ally relative to the ~irst half portions tnereof. Such movement of the second half portion of the driving pulley ,:
changes the effective pitch diar.~eter of the driv.ing pulley, lQ and the magnitude of the tension exerted on the belt. This change in tension on the belt results in the effective pitch ~iameter of the driven pulley changing due to var-iation in the lateral force ir~lposed on the spring loaded second half portion of the driven pulley. Thus, the -power drive transmission asse~bl~ constantly changes the ! ratio of tie ef~ective pitch diameters of the driving and driven pulleys to maintairs the first and secon~ elec-tric signals in balance. The spacing and configuration of the lightreflecting surlaces is so chosen that the first and second signals are in balance when the engine is operating to p~oduce torque on the driven pulley that, has a desired relationship to the torque curve. The light reflecting surfaces will normally be so chosen that the first and second signals are in balance when the en-gine is producing less than the maximum torque possible through the driYing pulley, for otherwise it would not be possible to accelerate the engine to drive the driving- ,' pulle~ at a greater rate of rotation.

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~768~3 The po~,er drive transmission assem~ly of the present invention has the advantaaes over prior art de-vices of this nature in that the invention provid~s:
l. Greater variation in effective pitch 5 dia~eter ratios bet~een the driving and driven pullevs;
2. Broader capability of accepting wide varia-tions of engine drive speed, horsepower and torque out-put;
3. Greater efficiency in that the invention does not require the capability to sense torque applied to the driven shaft;

4. Automatic or manual up or do;~n shifting of the effective pitch diameter ratios without disen-gaging the drive force;

5. Is at all times in balance in that there `
is no radially movable parts.

6. Can be made to fo110~.7 an electronically generated shif.ing pattern.
In another embodi~ent the objects Or the pre-sent invention are accompli5hed with the unique com-bination similar to that previously described. In the second embodiment the lateral movement of the second half portion of the driving pulle~ relative to the first half ~ ;
portion is fixed by a manual control acting together ~lith a feed~ack loop. The feedbac~; loop comprises a load sensor t7hich senses the load on the prime ~over an~ a automatic voltage level setting circuit. The auto~atic voltage level settin~ circuit is coupled betlleen the man--7_ . :

76~343 ual co~trol and the power meclns that move the second half portion o~ the driving pulley. The ou.put of the loa~
sensor is couplecl to an input of the voltage limi~ing cixcuit such that the maxirnu~ level o~ the voltage ap-5 pliec ,o the pot~er means iS fi~ed ~y the load sensor.
In the second embodiment the prime mover ro-tates at a constant rotational speed and the ef~ective pitch dia~eter ratio betwe2n the driving and driven pul-le~s is primarily set by the manual control. Accordingly, even thouyh the prime mover is operating at a constant rotational speed, the output rotational speed from the - transmission assembiy may increase or decrease in response to the manual control so long as the load on the pri~e mover does not exceed some predetermined set level. If ~he load on the prime mover exceeds the set level, the voltage limliting circuit ~`7ill reduce the voltage a2plied ,~, to the po-.~7er means in response to the output of the load sensor to reduce the effective pitch diameter ratio be- -tween the driving and driven pulleys ihereby preventing the load on the prime mover from exceeding the predeter--; mined maximum load set by the load sensor.
In another embodiment of the present invention, the objects are accomplished by a uniclue com~ination sim-ilar to that previously described except tnat the driving pulley and driven pulley are interchanged in position. In ot'ner words, the clriving pulley is utilized as the driven pulley and the driven pulley is utilized as the driving, pulle~. In the third embodiment, the prime mover is of -~

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768~3 the type ~.~hose rotatiollal speed varies over ~.:ide ranges and it is d~sirable that the output oE tne po~7er trans-mission be a constant rotational speed. In this em~odi-7mellt the position o~ the s~cond hal~ por-tion of the driving pulley is controlled b~ ~ fee~back loop. The ~eedbac~ loop com.prises a sensor ~Jnich senses the ro-tational speed of the driven pulley and supplies an out-put to a comparator means wnich compares the output of the speed sensor with some reference signal w~ich is ld related.to tne desired rotational speed of the driven pulley. The comparator circuit generates a signal to vary the effective pitch diameter ratio between the driv-ing and driven pulle~7hich is applied to the power means -on the driven pulley so that tne outpu-t signal from the 1~ speed sensor is equal to the reference signal.

~rief Descri?tion o ~ne_DraT7in~s The above-mentioned and other features and oh-jects oE the pr~sent invention will become more apparent by reference to the following description taken in conjunc-tion Witil the accompanying dra~7ings, ~herein like reference numerals deno~e like elements, and in which: . ~
Figure 1 is a perspective view of an internal : -co~ustion engine in driving arrangement with the power drive transmission assembly.
2~ ~igure 2 is a longitudinal cross sectional view of a power drive transmission assembly.
Pigure 3 is a fra~mentar~ cross sectional vie;, 0~ d portion oE the asse~ly within tlle oval defined ~y ' .~ . r .~ .
. _ 9 ,,~ .

1~ 43 ?hantom line in Figure 2 and identified by the nume-al 3, an~ illustratina the positioning of tlle patterned light reflecting surface on æ part of the driving pulley.
Fi~ure A iS a top plan view of a siheet having 5 patterne~ liqnt reflecting strips defined tnereon, with each strip being adapted ~or use on the assemblv to achieve a particular power output tnat is related to the torque curve ol the engine.
Figure 5 in diagram form illustrates in con~
junction with an endles~ V-belt the effective pitch dia-meter ratios that may be achieved between ~ driving and driven pulley. ;
Figure 6 is a top plàn view illustrating the lateral shifting or portions of the drivin~ and driven pulleys, Figure 7 is a simplified top plan view or a -~
second form of the invention.
Figure 8 discloses plotted curves t~at illus-trate the power output of the invention relative to the torque curve.
.
Figure 9 is a diagram illustràting the elec~
trical circuit used on the invention.
Figure 10 is a top plan view of a third form of the invention.
; ~S Figure 11 is an enlar~ed fra~mentary cross~ ^~

sectional vie~ of ,he third form of the invention.
Figure 12 is a perspective vles~7 01 t~vo o ~he co~lpon-nts used in the third form of the inventior.

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1 Figure 13 is a block diagram of a second embodiment of the invention wherein the prime mover is a source of constant rotational speed.
Figure 14 is a third embodiment of the present invention wherein an output of constant rotational speed is desired.
Figure 15 is a top plan view of a sheet having a pattern of light reflecting strips defined thereon.
Figure 16 is a cross-sectional schematic view of one tO embodiment of a linear actuator.
- Figure 17 is a simplified view taken along the lines 17-17 of Figure 16.
Description of the Preferred Embodiment An internal combustion engine C has a first form of power drive transmission assembly D operatively associated therewith as shown in Figure 1. Engine C and assembly D are illustrated in Figure 1 as supported on a base frame 10, which when the invention is used may be a part of a vehicle chassis not shown.
Engine C as illustrated in Figure 1 includes a drive shaft. In Figure 2 a drive shaft 12 is illustrated that has a driving pulley F mounted thereon, and this pulley is capable of driving an endless V-belt 14. Driving pulley F
is of split structure and includes a first half F - 1 that is by a key 16 rigidly secured to drive shaft 12. Drive shaft 12 has a first grooved wheel 18 rigidly secured thereto. The first pulley half F - 1 is formed with an outwardly tapering interior first face 20 as may best be seen in Figure 2.
Belt 14 has oppositely disposed side walls 22 that . -: '', .
~:.'- ' 1076843 - ~

taper in~ardly toward one another a, su'~stc.n.iall~ the same angle as that Of the firs-t face 20.
First pulley half F~l as shown in FicJure 2 includes a c~lindrical firs-t hub 2~, with the first hub extending outwardly away from the first surface 20.
Fi rst pulle~ F also includes a second hal F-2, ~Jhich second l~lr includes a second cylindrical hub 26 in hich a longitudinal bore 28 is formed. The bore 28 is slidably engaged by first hub 24. A key 30 is secured to first hub 24 ana slidablv engages an interior groove 32 in second hub 26 to prevent the first and second ~ulley hal~es F-l and F-2 rotating relative to one another as sho-~i-n in Fi$ure 2. First half F-2 has an outwardli~ .a2ering interior face 34, that tapers at substantiall~r the same angle as one of the belt side walls 22. The first and second faces 20 and 34 taper outwardl~ away from one anotner as sho~n in Fi~ure 2.
Bore 28 on ~he ir.ner end thereof develops into a re-cess 36 that is partially defined by a ring shaped 20 body shoulder 38. ~ snap rinc 40 is mounted in ~ ;
circumferentially extendin~ groove 42 formed on the - r: :
; ~ outer surface of first hub 24. The snap ring 4~ serves as a stop when contacted by body shoulder -4-2 ~o limit the inward movement of second pulley half F-2 relative to first half F-l. It should be understood-that the assemb7y of Figure 2 may be em~loyed with an asse~bly such as snown in Figure 1 or other assemblies. ~he co~mon n~mDerins and lettering between Figure 1 and 2 is only suggesti~e Of one possible form of cooperation .. ~ .

1C~761 343 ?

A housing G is secured to enyine C by bolts 44 or o~her suitable fasteniny means Housing G has an outwardly disposed open encl that is normally closed by a first plate 46 that is removably secured thereto by bolts 48. First plate 46 has an opening 50 therein. A slot 52 is farmed in the .:
side of housing G as shown in Figure l A second plate 54 is provided that is disposed outwardly from first plate 46 and is removably secured thereto by screws 57.
Returning to Figure 2, the outer end of a second hub 26 has a circular member 56 secured thereto by screws .- 58. A bore 60 is formed in the center of member 56.
A rigid cylindrical shell 62 haviny an outwardly extending flange 64 engages opening 50 and is gripped between first and second plates 46 and 5~ when screws 57 are tightened as shown in Figure 1. A block 66 is slidably supported in cylinder 62, with the block having a pin 68 that extends outwardly therefrom to slidably engage a longitudinal slot 70 formed in the shell. A ball bearing assembly 72 ~ is disposed between member 55 and block 66. In Pigure 2 it will be seen that a compressed helical spring 74 is disposed in the open portion of the bore 28 and is in abutting contact with second pulley half F-2 and member 56.
Spring 74 at all times tends to move second pulley half F-2 away from first pulley half F-l.
- A threaded rod 76 is rotatably supported in a fixed longitudinal position in second plate 54 as ,'!'! ' :
shown in Figure 2, and rotatably enga~es a tapped bore ~: :
78 formecl in block 66. A grooved wheel 80 is secured : .

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1~76843 to the ou-tt~ardly projecting end of rod 76 to per~it th~Q
rotation thereof. Rotation of the rod 76 moves bloc~;
66, ring shd~ecl me~her 5~, ~all bearillc~ ass~ly 72 and second pulley half F-2 as a unit toward or away from first pulley half F-l dependent upon the dlrection of rotation of the rod 76.
An-endless belt 82 as may be seen in Figure 1 engages grooved whe~l 80, with the belt extending to a grooved wheel 84 on the drive sha~t of a reversible electric motor 86, which motor is supported in a fixed position relative to housing G b~ conventional I~eans (not shown). The motor 86, belt 82, grooved wheels 80 and 84 together wit'n tl~reacl2d rod 76 and block 66 serve as a linear actuator to move the second pulley - 1 3 half F-2 laterally relative to first pulley half F-l.
The means by ~hich the motor æ6 is electrically ener-gi2ed will be explainea later in cletail.
mhe base 10 has brac~et meansl86 of conven-- tional structure secured thereto as ~ay be seen in Fig-ure 1, which bracket means rotatably su~port a ~rans-versely disposed driven shaft 88. A driven pulley ~ is -~
mounted on shaft 88 as shown in Figures 1 ancl 2, and is engag2d by belt 14.
The driven pulley H includes a first half portion H-l that is rigidlv secured to driven shaft 88 by a key 90. Key 90 engacJes a longitudinal slot 92 in driven shaft 88 and a slot Qa formed on tne inierior of a cyllndrical hu~ 96 that projects from first ~.al~ H-l "

~ii7~843 as shown in FicJure 2. The driven pulle~ ~ includes a second half }l-2 tha~ has a cylindrical shell 98 pro-jecting therefrom that is slidably mounted on a hub 96. ~ -A ~ey 100 enc,7a~es aligned longitudinal grooves 102 and maintains tne first and second halves H-l and ll-2 in non-rotatable rela~ionship relative to one another as shown in Figure 2.
A compressed helical spring 104 encircles hub 98 and is in abutting contact with second half H-2 and 1~ a retainer 106 that is held in a fixed position relative to driven shaft 88 by a resilient clip 108. Th~ clip 108 engages a circumferential groove 110 formed in the free end portion of hub 96 as may be seen in Figure 2.
When the second half F-2 moves transversely ; ~`
1~ relative to the sècond half F-l, the tension and lateral orce exerted by the belt 14 is ~aried to overcome the .~ :
force exerted ~y the spring 104, with the effec,ive pitch diameter ratio between the driving pulley F and "~ ariven pulley H var~ing bet~7een the extremes shown in Pigure 5. It ~ill be particularly noted that the por~
.: .
tions of the driving and driven pulleys F and ~ engaged : by belt 14 at all times remain axially aligned for as shown in Figure 6, when the belt 14 moves from a posi-tion sho~n in solid line to one shown in phantom line : 25 the lateral silifting of tihe second movable halves F-2 : ;, : , and H-2 is in the same direction. Tnus, there is no ;-tendenc~ ror belt 14 to becom- disengaqed from the driving and driven pulleys as the effective pitch ratios thereo~

~ is varied.

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i~76843 :

Referring to Figure 1 a grooved ~heel 18 (such as sho~n in Figure 2) engages an endless belt 112 tnat dri-~es a grooved wheel lla secured to a rotatable shaft 116 Ols an electrical generator 118. The generator 118 is secured to a bracket 120 that is affixed to the engine C by conventional means such as bolts 122 or the like.
Driven sha~t 88 as may be seen in Figure 1 has a power - take off sprocket 124 mounted thereon that is engaged by a lin~ belt 126 that delivers rotational power from engine C io a desired source. ;~ ;
The torque curve J of engine C is shown in ~- Figure 8 in solid line. The torque that is desired to be delivered by tne driven shaft 88 from engine C through trans~ission D b~ varying the pitch diameter ratios of of the driving and driven pullevs ~ and H is indicated by the torque curve K in Figure 1.
~orsepower is a product Ols torque and rota- -~
~i~ tion speed, ana the horsepowrer at any given r.p.m. will vary directlv with the torque. By selectivel~ varying ;;~
the pitch diameter ratios oS the driving and driven pul-leys F and H the torque curve ~ in the region thereof be-tween 5500 and 10,500 r.p.m. as shown in Figure 8 can b~ ;~
:,, ` made substantially flat.
~he transmission ~ in combination with the auto~atic sensing device L now to be described permits " the por.;er outpu~ on the driven shaft 88 to follow the-torc~ue curve J to a desired degree, and obtain usable .:

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- ~76843 ?o~;~r at the driven shaft in a more er~icient manner t;~an by manually var~ing the pitch dia~eter ratios of the dri~ing ~nd Ariven pull~ys F an~
sheet P~ of pliable maLerial, such as paper or the like is provided tha. has a nu~er o~ strips to M-4 inclusi~e deîined th-reon. Fach strip M-l to - ~_a has a sequence of triangular shaped light deflecting - areas N-l, N-2, N-3 ~nd N-4 defined thereon and these areas beiny separated by dark non-light reflecting tri-angular areas 0-1, 0-2, 0-3 ana 0-4. The triangular areas ~-1 to N-~ and 0-1 and 0-4 are of dif~erent con-figuration and ~idths for reasons tnat will later be ex~lained.
One of the strips M-l to M-4 has light re~lect-- 1~ ins and non-li~ht xeflectin~ areas of an appropriate con-figuration for engine C and is mounted on the hub 26 as shown in Figure 2 to encixcle the sa~e.
The desired strip ~I-l to M-4 is removably held :., , - .:
in the encircliny position on hub 26 by conventional means 2~ ~not shown) such as an adhesive or the like.

A source of electric energ~ is providedr suc~
., ~. .
as a storaye battery (not sho~n) which is charge~ when engine C is opera-ting by the generator 118. Electric energy is delivered from generator 118 to the source 23 through conductors 130 shown in Figure 1. The source of electric eneryy supplies electric power V to a num-ber of terminals that are identi~ied in Fiyure 9 by Lh2 letter P.

1~76B43 A light emitting diode 132 is pro~ided that directs a ~eam of lignt 13~ on the strip M-l as it ro-tates with hub 26 as shown in ~igure 9. The dio~e 132 is sup~orted by a bracket 136 from shell 62 as shor~tn in Figure 2~ A beam of light 134' is reflected from the areas N-l as tlley rotate to a transistor U that is elec-trically c~ductive only when the beam impinges thereon.
One terminal of lisht emitting diode 132 is connectecl to a terminal P b~ a conductor Q and tne other 10 ~erminal by a conductor R to ground S. A preampliFier ..
138, Schmidt trigger 140, monosta~le multivibrator 142 - and low pass filter 144 are connected by conductor 146, 148 and 150 as shown in Pigure 9. Transistor ~, pre-: amplifier 138, Schmidt triqger 140, monostable multi-1~ vibrator 142 and low pass filter 144 each have one ter-~inal P and the other terminal by a conductor R to ground S. `~
; T~e beam o~ light 13~' is intermittent and ;-; as it intsrmittently renders transistor U electrically - 20 conductive causes thne latter to deliver a pulsating voltage V to preamplifier 13~. The fre~uency of the pulses of voltage V is related to the rate of rotation of the driving pulley F, and the time duration of eacn pulse is related to the time it ta';es for each light ~-~5 reflecting area N-l to rotate past the beam 134. The time it takes ~or each light reflecting area ~i-l to rotate past the beam 134 is related to .he position of the second nalf F-2 oE driviny pulle~ L relative to tne ~ 3 ~07f6~343 first half ~-1 thereof, for .he lic~ht reflecting areas N-l m~-u7e laterally- concurren~ ith tne second half.
The pattern of t~e voltacJe V as it is altered the ele~.ents 138, 1~, 142 and 144 is shown plotted against ma~3litude ancl time in s~.all graphs adjacent tne elements in Fic3ure 9, and the low pass filter de-livering a relativel~ constant voltacJe B that in magni-tuc'.e is related to the rate a~ which the driving pulley F rotates. Volta~e B is delivered to a conduc,tor 148.
A second low pass ,ilter 154, inverter 156, su~mer 158 and power ~uffer 160 are connected by conduc- '-. ~ - .
tors 162, 164 and 166 as shown in Figure 9, ~Jith each of tne ahove iden~ified elements being connected to termin-als P and ground S by conductors Q and P~. ., Conductor 1~8 has a junction point 148a there- ' . .. .
-, in from which~a-conducto~-162 deliver.s`electric ener,gy in the squared voltage patter.n V' to the second low pass '' ~ilter 154. In~rerter 156 delîvers a voltage A to sum- ~
mer 158 that is related to the time it takes for a light ,' ~, - 20 re~lecting area ~-1 to move past beam 134 which in turn , , is related to tne transverse positioning of the second `'' hal- F-2 of clrivincj pulley F relative to tne first half ' "`
thereof.
Power bu~~r 160 has a conductor 168 extending , ,,' 2~ thererrom to a linear actua~or X which ~7hen actuated is ''~
capable of transversel~ movins second half F-2 of driving pulle~ F relative to first half F~l to var~7 the pitch .
dia~eter of ihe drivin~ pulle~7. The linear a=tuator ',' . , --lg-- . .

~ 76~343 r~lay be ei~her the first Sor.~ X-l thereof shosn in Figure 2 or a second form ~Y-2 illus.rated in ~igure 7 and la~er to ~e described.
T'he voltages ~ an~. B due to inverter 156 are 5 O$ different polarities. I~hen voltages A and B are equal they cancel one another and po~.~er buEfer 160 is not actuated to energize the linear actuator X. The ,"~
; motive po~,~er in actuator X-l is the reversible motor 86.
, . , ~ When voltages A and B are not equal po~er buffer 160 '` 10 causes a flo~7 of electric current to mo,or 86 through '' conductor 168 in a direction to cause the motor ~to ro-' , tate threaded roa 76 in a dirPction to vary the pitch dia-meter of the driving pulley F until A and B are again eaual.
The width of t~e licJht reflecti~ areas N-l is so chosen that the torque J O,c the driven sha~t 88 will have a desired relationship to the torque ~ of engine -:
C, ~or instance, the sesme-.l: K-l of torque curve as sho-~,n in Figure 8 may be so selected that the eflec-~; tive pitch diameter of driving and driven pulleys F and -` 20 ~I is 8 to 1, w~ile the segment X-2 ma~ have a pitch dia- -meter of 2 to 1. In all instances it is d,esirable that torque curve R be some-.~7hat less than torque curve'J to permit acceleration of the engine C. ' From the foregoing discussion, it is apparent to one s~illed in the art th~t an electric motor could be substituted for internal combustion engine and that any sensor or combination OL sensors which s~nse .he ro-tationsl speed of the prims movsr and the position of -2~- -.,:

.. . . " ., 1(~76843 the second half portion of the driving pulley can be su~stituted for the li~ht beam sensor dQscribed herein t~ithout departin~ from the spirit and scor~e of the pre-sent invention. ~^iithin this class OLC sensors or combin-5 ations of sensors LCalls sucn devices as magnetic sensors,,~matic sensors, hydraulic sensors and a sensor as sim~le as a cam follower coupled to thQ~ per of a linear resistor.
In Figure 7 a second form of the invention 1~ is shown in which the second form X-2 OCL the linear actuator is used. Elements in the second form OL the invention that are common to the first form are identi-- - fied in Figure 7 by the same numerals an~ letters ~revious-ly used ~ut with primes being added thereto.
` 1~ In the second form of the invention as shown ;l in ~igure 7 plate 46l has a first h~draulic cylinder 200 extending outwardly therefro~ in ~hich a piston 202 is ^ slidably mounted that has a recessea inner portion 204 ' ;
`-~ on ~hich the ball bearing assembly 72' is mounted, with one race of the assembly secured to hu~ 26'. Hydraulic ~luid Y may be discharged into and out of ~irst cylinder 200 through a passage 206.
- Passage 206 is in com~unication with th~e outer interior portion of a second hydraulic cylinder 208 that 25 projects from plate 46'~ A second piston 210 is slidably mounted in second cylinde~ 208. ~econd piston 210 has a tapped cavity 212 therein that is en~aged by a threaded shaft 214 that is driven by a reversible elec-.

1~6843 tric motor 215. Electric motor 216 rot~tes threaded shaft 214 when the motor is supplied witll electric power throu~h conductor l~S and a concl.lctor R in the ~anner previously described in connec-tion wiLh the ~irst form of the inven-tion~
~ hen the motor 21S is actuated by electric power received from power buffer 160, the threaded shaLt 214 is rotated to move second piston 210, with hydraulic fluid Y
being ~orced into first cylinder 200 to move first piston 202 and second pulle~ half F'-2 relative to the first pulley half F'-l until the pitch ratios of the driving and driv~n pulleys F' and H' is such that volta~es A and B are equal. The above described operation will continue intermittently as the load on driven shaft ~8' varies, and .:
as a result the torque delivered by driven shaft 88' will ~ollo-~ the curve K illustraLed in Pigure 8. Spring 74' .
~ tends at all times LO move second half F'-2 away from : .
first half F'-l.
In Figures 10 to 12 inclusive a third form of - 20 tneinvention is shown on which a third form X-3 of the linear actuator is used. Elements in the third form of the invention that are common to the first form are identified in Figures 10 to 12 by the same numerals and letters previous-ly used but witn double primes bein~ a~ded thereto. `~
2~ In the third form of the invention as illus- ~ ~
trated in Figures 10 to 12 a bracket 300 secured to first plate 46" by bolts 302 serves as a fi~ed mounting for the outer cylindrical portion 30~ of a hysteresis brake ~7f~343 306. The hys-teresis`~rake illus-tra~ecl is ~anulacture~
con~nerciall~ b,~ the Dele~and Division. hmeirican Precision Industries, Inc., East ~urora, ~e~ ~;or}: and serves as the third form OL linear actuator X-3.
Bra'~;e 306 has coils 308 in portion 304 that may be electrically energized t~roU~Il conductors 168, Q and R.
Brake 306 has a rota~able inner portion 310. Inner por-tion 310 is rotatably supported in outer porLion 30~ by - a pair of spaced ball bearing assemblies 312. The inner lo portion 310 has a nut 314 on the outer end thereof that i~ engages a threaded rod 316 that extends through a longi-- tudinal bore 318 in the inner portion. Threaded rod 316 ; ~`
on a first end 316a thereof has a slot 320 therein of rec-tangular transverse cross-section that is removably en-- 1~ gaged by an elon~ate cross-me~ber 322 that is secured to ,~circular member 56P b~ a pin 324. Inner portion 310 has a circular recess 326 therein that is enga~ed by a snap ring 328 that bears against the ball bearing assembly 312 `
nearest to circular mem~er 56". Snap ring 328 limits the 23 outward movement of inner portion 310 relative to outer portion 304 as ~ay be seen in ~igure 10. Nut 314 is secured to inner portion 310 by conventional means (not sho~n).
When coils 308 are not electrically energized 2~ cross mem~er 322 as it rotates causes concurrent rotation of inner portion 310, threaded rod 316 and nut 314 as a unit. Upon coils 3Q8 being electrically energized hy a ;signal received b~ the third for~ X-3 of the linear ac-':

:

-23~

1~76843 ....,`

~'tuator throush conductor 168 the inner portion 310 is stop~ed from rota~incJ, but t:ne threaded rod 316 con-tinues to rota.e relative to tl..e inner portion and nu-t 314. Rotation of threadecl rod 316 relative to inner portion 310 results in lateral movement of second hal' F"-2 to first half P"-l of drivin~ pulley F" to vary tne effective pitch cliameter thereof as previ~usly de-scribed in connectio~ ~ith the first form of the inven-tion.
- The use anc'~ operation of the invention has been described previously in deta l and need not be repeated.
- Furthermore, it should be apparent that linear actuator X ~.ay be imple~en~ed in severl other ways, such .
~s, but not limited to a hydraulic or edd,y curxent brake with-out departin~ from the spirit and .,cope of the invention.

RefPrring to Figure 1~, sho~Jn therein is ano~her - embodiment of the present nvention. Elements in this embodiment of the present invention that are co~mon to - -the other em~odiments are identified in Figure ~4 by the 20 sam~e reference numerals. '' '~Referring to Figure 14, the embodiment sho~Jn ` ~
th~rein includes a prime mover represented by electric ~ --motor 400 having a drive shaft 12. Driving pulley F
which is substantiall~ the same as the driving pulley F
2~ previously descri~ed is moun_ed on drive shaft 12.
Driving pulley F is coupled LO driven pulley H by V-belt 14. Driven pulley ~ is substan~ially the sa~e as the driven pulley H previousl,~ described. Linear actu--' '.

-2~-,, -. :. - . :,, : ,.,. : .

i~3761343 : .
ator x is substan~ th~ sa~e as X-l through X-3 previously clescribecl is coupled tc- second pulley nalf ~-2 of- driving ~ulley F. Po ition sensor 402 senses the position o~ second pulley F-2 and the output of position sensor 402 is cou~led to an input of compdrator driver 404. The output Oc comparator driver circuit 404 i5 coupled to linear actuator X.
Electric motor 400 is po~rered by a source of direct current represented by battery 406. Resistor 408 : ,. .
is cou21ed be~ween tne negative terminal of battery 406 -`~ and ground~ The terminal ormed by the negative ter~in-al of battery 406 and one end of resistor 408 is coupled to an input or voltage limiting circuit ~10 and the out-put Oc voliage li~itirg circuit 410 is coupled to an in-put of comparator driver circuit 404.
~ Jariable resistor 412 is coupled be~.een a ~inus source of direc-t current voltage represented by a ~Vs and ~round and the wiper of variable resistor 41 is coupled to an input o voltage limiting circuit 410.
Pedal 414 is mechanicall-~ coupled to the wiper of variable resistor 412 such that de~ressing pedal 41~ causes the wiper of ~ariable resistor ~12 to move such that the vol~age between the wiper and ground increases in mag-nitude toward -~rs. ~`
2 Th~ voltage limiter circuit 410 com~rises t-~io operational amplifiers 416 and 418. ~esistor 420 is coupled oetw~en the input OlC o~erational ~mpli.ier 416 ar.d the connection rormec~ ~ th~ negative termir.al of .

~, _ )~_ .: , -: .

:~76~343 ~' battery ~06 and one end o.~ resistor ~08. Capacitor 422 is couple~ be-t~;een the in~ut and output of amplifier 416.
~ariable resistor 42~ is coupled between a positive source of direc. current voltage represented b~ ~VL and ground.
Resis~or 426 is coupled between the wiper of variable re-sistor 424 and the input or operational amplifier 416.
~ne anode of diod~t~ 428 and the cathode of diode 430 are coupled to the output of amplifier 416. The cathode of diode 428 and the anode of diode 430 are coupled re-- 10 spectively to one end of resistor 432 and ground. The ot~er end of resistor 432 is connected to the input of operational am~lifier 418. The two ends of resistor 434 are coupled between the input of amplifier 418 and the wiper of variable resistor 412 and resistor 436 is coupled ~' - 15 between the input and out,ut of ampli~ier 418. ~he out-put of amplifier 418 is coupled to an input of comparator ~
~river circuit 404. ' ~ , In practice, positi.on sensor 402 can be sub- ~ ~
sta~ially the same as automatic sensing device L. Also, ,, com~arator driver circuit 404 can be substantially the same as that portion of electronic circuit of Figure 9 co~prising t~e series connection of preamp 138, Schmidt trigger 140, low pass filter 154, inverter circuit 156, summer 158, and power.-buffer 160 except tha-t the output 25 of voltage limiter circuit ~10 is applied to an input of summer 158 on conductor 152. ', For the sake of illustration, assu~.e that the output rotational speed of'electric motor 400 is a con-. t .' ~ ' ' ~ ' ; . .'. , ~ , ~076~3~3 . . .
stant and that the l.Yiper contact oF v~riable resistor 424 is set such that .he voltage betr7een the t~iper con,ac~ :
an,d sround is some positive value corresponding to a pre-determined maximum load condition. ~urtller, assume that -5 pedal 414 is in a position such that the resistance bs-; tween the wiper arm of variable resistor 412 and ~round is substantially 0 thereby making the input to amplirier , ' , , 418 substantially 0 volts. If pedal 414 is depressed, -the wiper arm of variable resistor 412 is moved such that the voltage increases in a negative direction from 0 to~ard -Vs thereby causing the voltage at the input of operational amplifier 418 to increase in the negative direction. As the input voltage o~ ampli~ier 418 in-creases in the negative direction the output voltage of amplifier 418 increases in the positive direction and is coupled to the input of col~lparator driver circuit ~`' 404. Comparator driver circuit 404 compares the signal ;, fro~ position sensor 402 with the output of amp~ifier ':
418 and if there is a di-~ference applies a signal to , linear actuator X to move second pulley halE F-2 relative to ~irst pull_~ half ~1 until the difference bet~eèn -the two signals is substantially 0~ Accordingly, the efrective pitch diameter ratio between the driving and driven pulley is varied and tne load on electric motor aoo increases. ,~
As the load on electric motor 400 increases, tne current supplied to electric motor 400 b~ bai~ery 406 increases thereb~ increasing the vo~tage drop across , resistvr 408 in a negative direction. So long dS ,r.~

. ~ , ; , .~.

~76843 voltage drop across resistor ~08 is smaller in ~lagnitude than the positive vol-tage set by varicible resistor 424, thè output voltage OL the integrator formed bv ampli-; fier 41~ and feed~ac~ capacitor 422 increases in a ne~
ative direc.ion. So long as the output voltage of ampli-fier 416 is a negative, diode 428 is reverse biased eE-fectively isolating the input of amplifier 418 from the output of am~lifier 416. Accordingl-y, so long as the output of amplifier 416 is negative, the output of am-plifier 418 will vary directly in proportion to move~
men~ o' pedal 414. To prevent the output of amplifier 416 from becoming too negative, diode 430 coupled between the out~ut and ground holds the output voltage at a minus one diode drop. ;
.lhen the load current through resistor 408 reaches a point such that the voltage drop across resis-tor 408 ~ecomes greater than the voltage set o~ varia~le resistor 424, tne inpu'. voltclge on amplifier 416 becomes increasingly more negative thereby causing the ouput o 2Q- ampliiier 416 to integrate toward a positive voltage.
The increasing positive voltage at the output of ampli-fier 41~ is reflected-at the input of amplifier 418 where it is additively combined with the negative vol-tage corresponding to the voltage drop between the wiper 2~ of variable resistor 412 and ground. Accordingly, the negativa voltage ap~earing cat the in~ut OL a~plifier 418 `~
ceases to continue to increase in the negative direction and the output voltage of amplifier 418 ceases to increase ;~ ~

;
in tihe posi-tive direction as pedal 414 is depressed. ~ur-thermore, so long as the load on elec-tric motor 400 is in excess of some preselecte~ value, the output volt~ge of amplifier 418 will ~ecrease, thereby causing line~r actu-ator X to move the second pulle~ half F-2 relative to first pulley half F-l to reduce the load on electric ~otor 400 thereby reducin~ the voltage drop across resistor 408 un- ;
til the drop across resistor 408 e~uals the voltaae pre- ~ -set on variable resistor 424. When the voltage across resistor 408 and tne voltage preset on variable resistor ; 424 are equal, the input voltage on amplifier 426 is sub-stantially 0 and t~e integrator formed by amplifier 416 an~ capacitor 422 will cease to inte~rate up in a positive direction and hold the outpu' voltage at some constant positive value. Similarly, if the load on electric motor 400 drops below the preset load, the output voltage of a~ lifier 416 will inte~ra,e downward until it becomes a negative value again there~y allowing the output of amplifier 418 to be directly responsive to movements in 2~ pedal 414. ~ ~;
-~.
As previously staied, it should be ap arent to ~-one s~illed in the art that the function o~ position sensor 402 can be performed ~y sevsral different types of sensors without departing from the spirit and scope 2~ of the invention. Furthermore, the description of cir-cuits which 7ill perform the comparator function an~ t~e voltage limiting function are meant to be purely illus-trati~e and not determinative of th.e ~nvent1on. Also, the load on electric motor 400 çan be sensed ~y any number 30 of current sensors availa~le in the art -;
.. . , . . -, .. ~ :

- ~76~3 1-Referring to Figure 14, shown therein is ano-th~r embodimen-t o~ the present invention. Elements in this embodiment of the prssent invention that are co~on to the othex embodiments are identified in Figure 14 by the same re~erence numerals.
Referring to Figure 14, the embodiment shown therein incluaes a prime ~over 450 havin~ a drive shaft 12. Drivin~ pulley F~ wQich is substantially the sa~e ~s tne driven pulley ~ previously described is mounted on drive shaf-t 12. Driving pulleyFY.is coupled to driven pulleyHF b~ V-belt 462. Driven pulley~ is substantially the s~me as the driving pulley F previously described.
Linear actuator X substantially the same as the linear actuators Xl through X3 previously described is coupled to second pulley half F2 driven pulleyHF. Speed sensor 452 is coupled to driven pulley P~ and the output of speed -sensor 452 is coupled to an input of comparator circuit 456. Reference le~7el source 454 is coupled to another in-put of comparator circuit 456 and the output of comparator circuit 456 is cou~led to the input of linear actuator X.
... .. ... : ..................... . . . .... ... ~... . ....... . .
In practice, speed sensor 452 can be substantiall~
the same as automatic sensind device L except that the dark nonreflecting areas may be of constant longitudinal width as shown in Figure 15 instead of being triangular. It is understo~
that the particular pattern shown is a simplified schematic-fonm and other forms and shapes may be desirable. Also, compar~

, ,,; ~.
circuit 456 can be substantially the same as -that portion --of the electronic circuit of Figure 9 comprising the series ~ - ' ' ..

'; ' ' . - ' .:

.; . . -.- ;i ,. ~ i ~ .;i, ... .... .... . .. ..
.. . . . . ~ . .. . . . .. . . .. . ..... ~, .. ... ,.. ~, .. .... . .... . .. .. . .. . . .. . . i - - ( ~076~343 connection of prealtlp 138, Schmid. trigger lao~ mono,~able multivibrator 142, low pass filter 14~, su~er 158 and power bu~fer 160 except 'ha, reference level ~54 is a~-plie~~ to the summer on conduc.or 16a Fur-thermore, the 5 re~erence level 454 can comprise a source of direct cur- -rent voltage represented by battery 460 coupled to a rheostat ~58 In operation, dri~Jing shaft 12 is rota~ed by prime mover 450 For the sake of illustration assume ~;
that the output rotational s~eed of prime mover 450 is not a constant and varies over some range The varying '~
rotational rate of prime mover 450 is transmitted via shaft 12, driviny pulley FH and V-belt 462 to driven pulley ~F Tne rotational speed of driven pulley ~F is sense~ by speed sensor 452 which generaLes an output to comparator circuit 456 Comparator circuit 456 compares the ou,put from speed sensor 452 with a reference level 454 If the output from speed sensor 452 and the reference level are ~`;
not equal, comparator circuit 456 delivers an output to ~ ~-energize actuator X to move the second half F~2 of dri~en pulley ~F to vary the effective pitch diameter ratios o~
the d~iving and driven pulleys at FH and ~F until the out- ;
put of spe~d sensor 452 and the reference le~-el are e~ua~
Accordingly} so long as the output from speed sensor 452 and the reference level 454 are equal, the speed of ro-tation of driven pulley HF is a constant irregardless of the changes in rotational spe-d of the driving pulley FH

.. ' . ~.
~:

- .- - - :- ,-, , . .;-~L~76843 A s~ecific embodiment of the linear actuator - that may be employed with the system of Figure 9 is shown in Figures 16 and 17 showing a housing S00 which encloses the pulley 502 comprising a movable pulley hal~ 504 and a fixea pulley half 506 The ~ixed pulley hal~ 506 is mounted to be driven directly by the output 542 of the prime mover (e.g , output of the interna:l combustion engine, electric motor, etc.). The fixed pul:Ley half 506 is thus fixed ~ -longitudinally with respect to movable pulley halE 504 which is adapted to slide longitudinally (arrows 508) with respect to fixed pulley half 506. The fixed pulley half 506 contains a bearing insert 510 fixedly secured in an opening 512 in movable pulley half 504. The bearing 510 has a con~iguration as shown in Figure 17 comprising a plurality of splinelike members which slidingly engage a matins hub 514, which hub portion has a ma-tching male cross-section to matchingly engage the bearing 510 Thus, it can be seen that the movable pulley half 504 is free to slide in the direction o~ arrows 508 via bearins 51~ on .;
the l~ating spline members 514 of the fixed half of the pulley 506.
The movable pulley half 504 has an internal lip `:
515 against which the bearing 510 abuts The lip 515 also , receives a washer 516 which washer is adapted to slidinsly :. ~
.; 25 fit within the bore 517 of movable pulley hal~ 504 The ` ~.
washer 516 extends beyond lip 515 to engage the end o~ :
bearing 514 in fixed pulley half 506. The coil spring 51 abuts -the surface of the washer 516 and extends from the .

1~7~iB43 washer 516 to plate 528 which is secured to one end or the movable pulley half 504 by fastening means 523.
It can be seen that movement of the movable pulley half 504 in the direction of arrot~s 508 toward the fixed pulley half 506 will result in the spring 518 being compressed between washer 516 (fixed by the end of spline 514) and plate 528 (which moves with movable pulley half 504).
The plate 528 has fixed therein a circulating ballnut 522 which is a standard commercially available component. The ballnut 522 receives lead screw 520 ~ -~7hich is secured to disc 534 which in turn is rotatably mounted in rotary bearing 536 by ~astening means 538 (schematically shown). The lead screw 520 is also rotatably mounted at its end 548 in an opening 546 in the end of fastening means 540. The fastening means 540 secures the fixed half of the pulley 506 of the prime mover output :~
shaft as schematically inaicated as 542. Thus,ii~ can be -seen that lead screw 520 is mounted for rota~ion so that : .
it can rotate at the same speed as ballnut 522 and mo~able 2~ pulley half 504 which xotate as a unit or lead screw 520 may rotate at a different speed with respect to said ballnut and movable pulley hal~ 504. When a differential in speed -exists between the lead screw and the movable half of pulley 504, the ballnut will be displaced along the lead screw resulting in the movement of mcvable half pulley 504 and the compression of spring 518. ; `
The disc 534 which is secured to lead screw 520 forms part of an eddy current brake 530. The eddy current brake includes a plurality of coils 532 spaced around disc 534.

768~3 Thus, the coils of eddy current brake 530 ~ay be en~rgized to e~fect the force supplied to the disc 53a which in turn places a variable force on the lead screw that determines the speed of the lead screw with respect to ballnut 522.
A light and dark area sleeve 52S is mounted ~n the movable pulle~ half 504 and fixed thereon by snap ring 526.
The light and dark area sleeve has been previously described - in connection with Figures 4 and 9. The light and aark areas on sleeve 525 cooperate with light sensor 529 and electronic assembly 531 to provide position and RP
information as to movable pulley half 504.
In summary, the above described linear actuator operates to change the pitch of the pulley by movement of ~.
the movable pulley half 504 with respect to the fixed half 506 This movement is accomplished by the relative speed of the lead screw 520 with respect to the ~allnut 522 and movable pulley half 504 which rotates as a unit.
The speed of the lead screw is determined by ~he eddy -~ `.
current brake 530 as controlled by the electronics hereinabove explained with the speed and positional information of the movable half 504 determined by the -:. .
light sensor 529 and electronics 531 as explained in ~` aetail above. - . :
One additional specific novel aspect of the above-described embodiment is the configuration of the spline 514 and the mating bearing 510 shown in detail in Figure 17. It should be noted that the por-tions 511 of spline shaft 514 contact the belt 550. The configuration '.

(~
-` 10~6843 of portions 511 are such as to cause minimum ~e~r ol the belt 550. In addi-tion, these spline mer"bers contac-t and drive the bearing of movable halE 504 of the pulley.
The depth of grooves 513 are less than three-ei~hths of an inch and pre~erably the wall 519 is approximately one-quarter of an inch. This minimizes metal removal while maintaining the strength of the shaLt and beariny.
Both the configuration and the fact that there are ; pluralities of such spline members enables the movable ~ .
half 504 to be ef~iciently and effectively drive by ; spline 514. Thus, the spline and bearing members present an additional novel aspect of this invention. ~
In all cases, it is understood that the above- ``
aescribed embodiments are merely illustra~ive of but a - 15 small num~er of the many possible speci~ic embodiments ! which can represen-t application of the principles of the present invention. Numerous and varied o~her arrangemen-~s can be readily devised in accordance with these principles b~ those skilled in the art without departing from the spirit and scope o~ the invention. ~
. i.', ` ' . - ' ,, .
:" , :

Claims (27)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A power drive assembly for use in combination with a prime mover comprising:
a rotatably supported first shaft;
a rotatably supported second shaft spaced from said first shaft and parallel thereto;
a first pulley defined by first and second halves, said first half being rigidly secured to said first shaft and said second half being slidably mounted on said first shaft but non-rotatable relative thereto;
a second pulley defined by first and second halves, said first half of said second pulley rigidly secured to said second shaft, and said second half of said second pulley slidably mounted on said second shaft and substantially non-rotatable relative thereto;
an endless V-belt associated with the first and second pulleys;
force exerting means that tends to maintain said second half of said second pulley in a position relative to said first half thereof such that the effective pitch diameter of said second pulley is maximum;
spring means that tends to move said second half of said first pulley to a predetermined maximum spacing relative to said first half thereof;
a first means operatively associated with said spring means for moving said second half of said first pulley relative to said first half thereof when said first means is energized; and a second means for energizing said first means in accordance with a predetermined relationship thereby varying the
1. Claim 1 continued:
   effective pitch diameter ratio of said first pulley and said second pulley relative to the V-belt, wherein the second means comprises:
   (i) a third means for sensing the rotational speed of the first shaft, the third means generating a third output whose magnitude is related to said rotational speed, (ii) a reference level, and (iii) a fourth means for comparing the difference in the magnitude of the third output and the reference level and generating a fourth output to energize the first means to move the second half relative to the first half to vary the effective pitch diameter of the first and second pulleys until the third output and the reference level are equal.
2. 2. An assembly as claimed in claim 1 in which said force exerting means is a compressed helical spring that encircles said second shaft, with said spring having first and second ends, with said first end being in a fixed position relative to said shaft and said second end being in force exerting contact with said half of said second pulley.
   
   3. An assembly as claimed in claim 1 in which the first means comprises:
   a reversible electric motor;
   a threaded rod rotated by said motor;
   first and second hydraulic fluid containing cylinders that occupy fixed positions relative to said prime mover, said cylinder including first end portions connected by a fluid passage;
   first and second pistons slidably and sealably mounted in said first and second cylinders with said second
3. Claim 3 continued:
   piston having a tapped bore therein that threadably engages with said threaded rod; and bearing means disposed between said first piston and said second half of said first pulley for moving said second half of said first pulley relative to said first half thereof to vary the pitch diameter of said driving pulley when hydraulic fluid flows into and out of said cylinder through said fluid passage due to the electric motor being energized to move said second piston in said cylinder to vary the quantity of said hydraulic fluid in said first cylinder.
4. 4. An assembly as claimed in claim 1 in which said first means comprises:
   a threaded rod that extends outwardly from said second half of said first pulley and rotates concurrently therewith;
   a hysteresis brake that includes a stationary outer portion containing electrical coils and an inner portion that rotates freely relative to said outer portion except when said coils are electrically energized, said inner portion having a longitudinal bore therein through which said threaded rod extends;
   and a nut on said inner portion that is longitudinally aligned with said bore and engaged by said rod, with said rod rotating-relative to said nut when said coils are energized to stop the rotation of said inner portion, and said second half of said first pulley being moved laterally relative to said first half as a result thereof.
5. 5. A power drive assembly as claimed in claim 1 wherein said reference level is a voltage of preselected magnitude.
   
   6. In combination with a prime mover having a driving shaft to which rotational power is transmitted by said prime mover, a power drive assembly operatively associated with said prime mover, said assembly comprising:
   a rotatably supported driven shaft spaced from said driving shaft and parallel thereto;
   a driving pulley defined by first and second halves, said first half of said driving pulley rigidly secured to said driving shaft, and said second half of said driving pulley slidably mounted on said driving shaft and substantially non-rotatable relative thereto;
   a driven pulley defined by first and second halves, with said first half being rigidly secured to said driven shaft, and said second half being slidably mounted on said driven shaft non-rotatable relative thereto;
   an endless V-belt associated with the driving pulley and the driven pulley;
   force exerting means that tends to so maintain said second half of said driving pulley in a position relative to said first half thereof such that. the effective pitch diameter of said driving pulley is maximum;
   spring means that tends to move said second half of said driven pulley to a predetermined maximum spacing relative to said first half thereof;
   a first means operatively associated with said spring means for moving said second half of said driven pulley relative to said first half thereof when said first means is energized to vary the effective pitch diameter of said driven pulley;
   a second means for energizing said first means in accordance with a predetermined relationship thereby varying the effective pitch diameter ratio of said driving pulley and
6. Claim 6 continued:
   said driven pulley relative to the V-belt, wherein the second means comprises:
   (i) a third means for sensing the rotational speed of the first shaft, the third means generating a third output whose magnitude is related to said rotational speed, (ii) a reference level, and (iii) a fourth means for comparing the difference in the magnitude of the third output and the reference level and generating a fourth output to energize the first means to move the second half relative to the first half to vary the effective pitch diameter of the first and second pulleys until the third output and the reference level are equal.
7. 7. An assembly as claimed in claim 6 wherein said reference level comprises a source of direct current voltage of predetermined magnitude.
   
   8. An assembly as claimed in claim 7 wherein said second means comprises:
   endless surface defining means that occupy a fixed position relative to said second half of said driven pulley and rotate concurrently therewith;
   a plurality of circumferentially spaced, elongate light reflecting areas defined on said endless surface defining means, with each of said areas being of substantially constant longitudinal width;
   means for directing a stationary, continuous first beam of light onto said areas to be reflected therefrom as a second beam of intermittent pulses which vary in frequency in accordance with the speed of rotation of said driving pulley;
   
   a source of electric power; and
8. Claim 8 continued:
   an electronic circuit energized by said source of electric power, which circuit includes a phototransistor on which said second beam impinges to render the same conductive, said circuit further including means that receive the pulses of electric energy from said phototransistor and transform the same into an output voltage that corresponds in magnitude to the rate at which said areas move past said first beam of light.
   
   9. In combination with an internal combustion engine having a driving shaft to which rotational power is transmitted by said engine in accordance with a predetermined torque curve inherent to said engine, a power drive assembly operatively associated with said engine for delivering a rotational power out-put that is related to said torque curve, which assembly includes:
   a rotatably supported driven shaft spaced from said driving shaft and parallel thereto;
   a driving pulley defined by first and second halves, with said first half being rigidly secured to said driving shaft, and said second half being slidably mounted on said driving shaft but nonrotatable relative thereto;
   a driven pulley defined by first and second halves, said first half of said driven pulley rigidly secured to said driven shaft, and said second half of said driven pulley slidably mounted on said driven shaft and substantially nonrotatable relative thereto;
   an endless V-belt associated with the driving pulley and the driven pulley;
   
   Claim 9 continued:
   force-exerting means that tends to so maintain said second half of said driven pulley in a position relative to said first half thereof such that the effective pitch diameter of said driven pulley is maximum;
   spring means that tends to move said second half of said driving pulley to a predetermined maximum spacing relative to said first half thereof;
   endless surface-defining means that occupy a fixed position relative to said second half of said driving pulley and rotate concurrently therewith;
   a plurality of circumferentially spaced, elongate light-reflecting areas defined on said endless surface defining means, with each of said areas varying longitudinally in width;
   means for directing a stationary, continuous first beam of light onto said areas to be reflected therefrom as a second beam of intermittent pulses which vary in frequency and duration in accordance with the speed of rotation of said driving pulley and the position of said areas longitudinally relative to said first beam;
   a source of electric power;
   electric power-operated means operatively associated with said spring means for moving said second half of said driving pulley relative to said first half thereof when said power operated means is electrically energized to vary the effective pitch diameter of said driving pulley, and the effective pitch diameter of said driven pulley varying in response to variation of the tension on said belt as the effective pitch diameter of said driving pulley varies; and an electronic circuit energized by said source of
9. Claim 9 continued:
   electric power, which circuit includes a phototransistor on which said second beam impinges to render the same conductive, with said circuit including first and second portions that receive pulses of electric energy from said phototransistor and transform the same into first and second voltages that correspond in magnitude to the rate at which said areas move past said first beam of light and the duration of time of each of said pulse of said second beam of light, with said circuit also including first means for comparing the difference in magnitude between said first and second voltages, and second means responsive to said difference for delivering electric power to said electric power-operated means to move said second half relative to said first half to vary the effective pitch diameters of said driving and driven pulley until said first and second voltages are equal whereupon said engine operates in a desired relationship to said torque curve in delivering torque to said driven pulley.
10. 10. An assembly as claimed in claim 9 in which said force-exerting means is a compressed helical spring that encircles said driven shaft, with said spring having first and second ends, with said first end being in a fixed position relative to said shaft and said second end being in force-exerting contact with said half of said driven pulley.
11. 11. An assembly as claimed in claim 9 in which said endless surface defining means is cylindrical in shape and said light reflecting areas defined thereon are generally triangular in configuration.
12. 12. An assembly as claimed in claim 9 in which said surface-defining means is an endless flat band and said light reflecting areas defined thereon are generally triangular in configuration.
13. 13. An assembly as claimed in claim 9 in which said power operated means includes:
    a reversible electric motor that is actuated when it receives electric power from said second means;
    a rotatably supported threaded rod that is rotated by said motor;
    a fifth means that threadably engage said threaded rod and move longitudinally relative thereto as said threaded rod rotates; and a sixth means for transmitting said longitudinal movement of said fifth means to said second half of said driving pulley to vary the pitch diameter of the latter.
14. 14. An assembly as claimed in claim 13 in which said fifth means is a rigid block that has a tapped bore therein that engages said threaded rod.
15. 15. An assembly as claimed in claim 14 in which said sixth means is a thrust bearing having first and second independently rotatable portions that transfer longitudinal movement of said block relative to said threaded rod to said second half of said driving pulley.
16. 16. An assembly as claimed in claim 9 in which said first portion of said electric circuit includes a preamplifier, a Schmidt trigger, monostable multivibrator and a low pass filter in series, with said first voltage flowing to said first means.
17. 17. An assembly as claimed in claim 9 in which said second portion includes a low pass filter, an inverter and summer that are connected in series with said low pass filter being connected to the output of said Schmidt trigger, and said second portion delivering said second voltage to said first means.
    
    18. An assembly as claimed in claim 9 in which said power operated means includes:
18. Claim 18 continued:
    a reversible electric motor;
    a threaded rod rotated by said motor;
    first and second hydraulic fluid containing cylinders that occupy fixed positions relative to said engine, said cylinder including first end portions connected by a fluid passage first and second pistons slidably and sealingly mounted in said first and second cylinders with said second piston having a tapped bore therein that threadably engages said threaded rod; and bearing means disposed between said first piston and said second half of said driving pulley for moving said second half of said driving pulley relative to said first half thereof to vary the pitch diameter of said driving pulley when hydraulic fluid flows into and out of said cylinder through said fluid passage due to said electric motor being energized to move said second piston in said cylinder to vary the quantity of said hydraulic fluid in said first cylinder.
    
    19. An assembly as claimed in claim 9 in which said electric power operated means includes;
    a threaded rod that extends outwardly from said second half of said driving pulley and rotates concurrently therewith;
    a hysteresis brake that includes a stationary outer portion containing electrical coils and an inner portion that rotates freely relative to said outer portion except when said coils are electrically energized, said inner portion having a longitudinal bore therein through which said threaded rod extends;
    and a nut on said inner portion that is longitudinally aligned with said bore and engaged by said rod, with said rod
19. Claim 19 continued....
    
    rotating relative to said nut when said coils are energized to stop the rotation of said inner portion, and said second half of said driving pulley being moved laterally relative to said first half as a result thereof.
20. 20. An assembly as claimed in claim 1 wherein the first half of the first pulley has a plurality of spline members in sliding and driving relationship with the belt, the portion of the spline members which are in contact with the belt having a smooth configuration.
21. 21. An assembly as claimed in claim 20 wherein said second shaft includes a lead screw and said positioning means includes a ballnut member fixed with respect to said second half and rotatably mounted on said lead screw for longitudinal movement.
22. 22. An assembly as claimed in claim 21 wherein an electrically energized brake means is mounted in cooperative relationship with respect to said second shaft to apply a force there to be con-trolled by an electrical signal.
23. 23. An assembly as claimed in claim 22 wherein said brake means is an eddy current brake having a disc mounted on said second shaft.
24. 24. An assembly as claimed in claim 20 including a spring means that tends to move said second half of said first pulley to a predetermined spacing relative to said first half thereof.
25. 25. An assembly as claimed in claim 20 wherein said second shaft includes a lead screw and said positioning means includes a ballnut member fixed with respect to said second half and rotatably mounted on said lead screw for longitudinal movement.
26. 26. An assembly as claimed in claim 25 wherein an electrically energized brake means is mounted in cooperative relationship with respect to said second shaft to apply a force there to be controlled by an electrical signal.
27. 27. An assembly as claimed in claim 26 wherein said brake means is an eddy current brake having a disc mounted on said second shaft.