Note: Descriptions are shown in the official language in which they were submitted.
~ 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
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~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
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- ~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
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~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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976843
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~ -
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~ 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.
, _5_
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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-
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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
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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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- ~76843 (~
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
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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
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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
: .
:- -13 ~ :
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.
.
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
.:
'''
-15~
.. , . ~
~, . . .
- ~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
-22-
~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
;~ ~
1076B43
;
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
-32-
.
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
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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.
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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
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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. ~
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