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Патент USA US2412360

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Dec. 10, ¿1946.
' 2,412,360
Filed March l4, 1942
2 Sheets-Sheet v.1
Dec. .10, 1946.
c. ' F. scHoRN
_ Filed March 4, 1942
2 Sheets-Sheet 2
Patente'd Dec. 10, 1946
Carl F. Schorn, Detroit, Mich., assigner to George
M. Holley and Earl Holley
Application March 4, i942,V serial No. 433,371
4 Claims.
( Cl. 170-135.6)
This invention relates to the control of a vari
I1 and ultimately engaging with a stop 14 l0
able pitch propeller driven by an airplane engine
in which the pitch is automatically adjusted to
keep the engine at any desired speed.
The object of this invention is to improve the
cated in a rotating arm 15.
A cam face 2l on the weight I5 engages with
the roller I8 mounted on the rotating element I9.
existing power controls so that a manually op
erated lever will select the speed of the engine
desired and that this speed Will automatically
select the manifold air pressure desirable at that
speed. The product of revolutions per minute
and manifold air pressure is roughly proportional
to indicated horsepower.
Another object of this invention is to avoid the
need for the use of broken links so that straight
through pull and push links can be used. As
a result, the control unit can be bench-tested,
as it is a self -contained unit.
Other objects are to facilitate the operation of
the device when cold and to provide means to
render the device inoperative when idling the
engine, and in both circumstances, to permit the
manual operation of the throttle. The reason
manual operation is necessary at low speed, es
pecially at idling speeds, is that the centrifugal
control of the variable pitch propeller is in op
eration at low speed.
In the drawings:
Fig. l shows the general elevation of the mech
A light spring 2li causes the roller I8 to be held
in contact with the cam face 2 I. By this means,
as the weight I5 rotates clockwise, the roller I8
is moved to the left the desired amount, thus
compressing thespring 28 and sliding a shaft 23
to the left which engages with a number of baro
metric elements 23, which are located in a cham
ber 24 which is in communication through a pipe
25‘with the pressure on the engine side of a
throttle 61 in an air entrance 19. The pressure
in the chamber 24 is usually described as at
manifold air pressure (see Fig. l). The reason
for this is that a supercharger is generally used,
in which case this connection 25 is on the engine
side of the >supercharger (not shown) which is
usually located just before the inlet valve air
entrance to the engine cylinder. To simplify the
disclosure the supercharger is not shown. The
barometric element 23 engages on the right with
the sliding shaft 22 and on the left with a servo
motor valve 216 which, in its turn, engages with
a compression spring 34, which takes up the back
lash between the valve 26 and the barometric
element 23 and the sliding shaft 22. 'I'he gover
nor characteristics are controlled by the spring
30 I 1 slightly modified by the springs 20v and 34.
Fig. 2 shows a plan view of part of the control
The movement to the left of the valve 26
causes a piston 21 to move to the right in the
Fig. 3 shows in cross sectional elevation the
cylinder 28. Oil under pressure is admitted to
combined centrifugal and barometric controls.
the servomotor through the pipe 53 and when
Fig. 4 shows a plan View of the manually op 35
the valve 26 is moved to the left, as it is when
erated lever and the links connected to it.
there is a decrease of pressure in the chamber
Y Fig. 5 shows the normal relation between revo
24, oil flows down a passage 54 and pushes this
lutions per minute and manifold air pressure,
piston 21 to the right. The oil at the right of the
and also the relation for best economy.
piston 21 then escapes through a passage 55
In Fig. 1 a speed control lever 36 slidabli7 en~ 40 through the valve 26 to an o-il outlet 56.
gaging with a quadrant 39 controls the pitch
A rod 51 is pivoted to the guide 58 which is
of a propeller 81 through alink 49, rack and
connected to a piston rod 59 mounted on the
pinion 16, centrifugal governor 11, a hydraulic
piston 21. The rod 51 is connected to a link 58
pitch-changing device 18, 19, 80. This device
mounted on a bracket 52 (Fig. 2). The link 58
forms no part of this invention and is a well 45 is formed in the shape of a crank and is con
known device in general use for several years.
nected to a link 50 (Fig. 2). The link 60 is con
A cam I0 provides a control to change the datum
nected to the throttle arm 6I (Fig. 1) through a
of the centrifugal mechanism to obtain better
economy curves. This is shown in Fig. 3 where
its rotation causes a sleeve II to slide in a bear
ing I2. 'I’he sleeve I I ' carries a rotating shaft
l I3 driventhrough a slot I4 at a speed in propor
tion to the speed of the engine. Governor weights
pin 62 on the end of which is a ball'63. ' The ball
63 slides in a slot in the element 54.
'I‘his ele
50 ment 54 is connected to the rod 41 which is piv
otally mounted on the control lever 36. lA lever
65 is mounted on a pivot 6E, which pivot is mount-`
ed on this main speed control lever 35. This
lever carries a link 48 which slides inside the ele
I5, one of which is shown pivoted at I6, rotate
clockwise at high speed compressing the spring 55 ment 64. Arounded end 68 of the link 48 en
gages with the ball 63 when the lever 65 is rotated
anti-clockwise and the ball 63 then engages with
a movable stop 69 which, when moved to the
right, compresses a spring 1E), manually closing
the throttle 61 by means of a throttle lever 6I.
A rod 43 is pivotally connected to the lever 65
tween the revolutions per minute of the engine
and manifold air pressure for bestv economy, that
is, the relation whichY exists when cruising lean
and running the Vengine slower and opening the
and this rod 43 carries a roller 38 which engages
with a surface êû of the quadrant 39. When the
throttle wider than with the normal curve.
When the cam I6 is rotated anti-clockwise, the
manifold pressure follows the curve of better
economy. The curve to the right shows the nor-v
roller 38 engages with an inclined surface 4I
and rides on a surface 42, the lever 65 is rotated.
The order to free the device from the servo-v
shown in the drawings,
motor and prevent interference with the above ~
sumes as a rule.
mal -curve with the cam liìin the position as
The slowe-ran engine
runs at any given power, the less fuel it con
mentioned manual means for closing the throttle,
The‘adjustable stop it, Fig. 3, which is mount
a by-pass valve 29 is provided which gives a free
' ed on the rod varm 15 limits the maximum re
opening 35 between the passages 54 and 55 when
sponse toA speed of the 1centrifugal weightV lever
this Valve is rotated anti-clockwise about 45° '
l5, so‘as to limit the maximum boost pressure.
Otherwise, during a. dive an excessivey boost pres
(Fig. 3) . ¿In the position shown, which is the op
erative position, a small opening 3| causes the
device to function as described above, but per
mits a circulation of a small quantity of oil at all
times in addition to that which leaks around the
sure would be possible. Points E and F (Fig. 5)
represent the maximum boost pressures con
trolled by the adjustable stop 11i and the movable
cam i6. The point 1E corresponds to înraximiim
piston 2l. A by-passpassage 32 -connects the
boost pressure with a normal Ycurve with the
passage 54 with the valve 29 and a by-pass 35i
cam l@ in positionshown and the point F to the
connects the passage 55u/'ith the valve 29.
maximum 'boost pressure with the maximum
A rod 46 is pivotally connected to- the lever 65 25 economy curve with camV l@ rotated counter
at the point which is normally located opposite
a pivot 6i on which the lever 36 is’mounted and
The inclined Vsurface 41 (Fig. 1') ' may be mount
rotated (Fig. Äl). Hence, rotation of the lever
ed on a slidable element 84 held on the quadrant
36 does'notnormally move the- link d6. The link ` se'by studs es and ae. The holes in the quad
é‘ßïtravels with the link 4l' and at a slightly faster 30 rant 3Q may be -slotted so that the exact location
rate than vthe link d'7, and hence slightly faster
of the inclined surface ¿il> maybe adjusted.
than‘the element ‘64. The link £6 is connected
with the lever 62 to the valve 29. Hence, when
ever the 'roller 38 >rides on the surface 42 and Yis
depressed, the valve 29 rotates anti-clockwise and
the servomotorZE, 21, 59, 56, 51 is rendered in
operative. ~At the same time the rounded end
68 engages with the ball ‘63 and the throttle 6l
is thus closed manually.
In order to permit this servomotor to be ren
dered inoperative at any time and not merely
whenthe lever 36 is rotated anti-‘clockwise into
the position for minimum speed, a handle 35 on
the throttle lever 35 is made so that >it can be
‘depressed and'when itis depressed, it'slides inside
`When the speed'control lever" 36 ¿is -moved
counterclockwise, the roller 38 rotates'on thefsur
iace 46 >down the inclined Ysurface fêlìandalong
the surface 132. When the ’throttle lever'361is
moved in 'the anti-clockwise direction (Fig. ~51),
that is to say, in the idling position, .the `rod f4!!
moves to the right and engages with Vthe v.ball
end’63 and closes the throttle lever'âi, causing
the throttle 6l to close. v'In OtherÍWordS, the 4con
trol ceases to'be auto-matic. The `~end oi ith'e >rod
'48 is provided vwith the element " ‘6% which is
' rounded to permit freedom of Vmoti-on in the "hol
a cylinder ‘l2 integral with-the lever 36, com
low element 64. When the control-lever Sâlis'in
pressing a spring 13 and carrying with it the
its low speed position, the end V68y kengages with
rod 43 and the roller -38. In order that the handle
the ball`63 which, in its turn, engageswith'the
35 can rotate without rotating the rod d3, a ball
sliding element 69 and compresses the spring lil.
joint isprovided-on the end of the rod d3. In 50 The throttle llever '6I isfthus moved anti-clock
order-vthat-the handle 35 can be locked in the
wise and the throttle 61 is closed manually.
depressedV position, a pin 59] is provided in the
As the lever 65 is rotated counter-clockwiseby
`handle and an L-shaped slot 5i in the cylinder
the depression of the -rod 43, it carries over to
12 is also provided. Hence, when the handle S5
ie left the link 4`6which causes the lever 582 to
isldepressed compressing the» spring 73, the pin
rotate anti-clockwise and thus moves withit‘the
5D is lowered to the level of the horizontalleg
valve 29 inthe anti-clockwise direction, vwhich
of the L-shaped’slot 5|.y The handle 35 is then
as described above,»places the passage y303 (Fig. 3)
rotated anti-clockwise 'looking` down and the pin
in a positionto allow free communication on both
5€! iscarried over to the rightinside the L-shaped
»sides of the piston 2l'. The servomotor thus'be
slot 5I. The roller 38 is thus locked in the lower 60 comes inoperative during theidling position and Y
position and the valve 29 is thus moved to permit
hence no unusual eiiort is required'to close the
free circulation between the sides of the piston
throttle vâì'ito theidling position.
2l. Hence, under this condition, the speed con
>Let us assume that’the engine isrun'ning Vat
trol Vlever 36 becomes an ordinary Ithrottle con
1500 revolutions per minute 'and manifold «air
trol lever, that is, it can be used to open the
pressure corresponding tothe point A on the'nor
throttle further than the position selected by
mal curve oiFig. 5. vLet vus assume further that
centrifugaly governor so that extra power is avail
the throttle 67 is to Vbe openedgThisfis accom
able Vif'the automatic mechanism fails.
plished as follows: ,
g '
Fig. 5 shows the relation between the revolu- _
The speed control lever 36 is. moved in the
tions per minute and the manifold air pressure
clockwise direction. The link'ßg 'acts'on the pro'- j
measured in inches of mercury. As the revolu
peller pitch gear 'Tl-8u, Immediately the'rev'o
ktionsîper minute increase, the permissible mani
lutions per minute would increaseandthemani
fold pressure increases. Hence,any increase in
fold air pressure would fall to the point B, be~
speed calls for an increase _in‘manifold pressure.
cause the element 69 `wouldnot immediately en
gage' the ball'63. The lowered manifold air pres
> V-The curve to the left shows the relation be
sure is due to the increased air iiow at a given
throttle and the fall in pressure causes the ele
ment 23 to expand. As a result, the valve 26 is
of the engine by varying the pitch of the propel
moved to the left, thereby admitting oil pressure
from the line 53 to the passage '54. The piston
21 then moves to the right carrying with it the
rod 57. rThe rod il@ moves to the left carrying
With it the pin 53 which moves the throttle lever
ler, a throttle lever, an automatic controlling de
vice therefor comprising a second engine-driven
centrifugal governor, a barometric device opera
tively connected to said second centrifugal gov
ernor and slidably mounted so that it is moved
bodily thereby, a variable pressure chamber en
closing said barometric device and connected to
6| clockwise, opening the throttle 61 and raising
the air inlet so as to be maintained at the pres
the manifold air pressure in 30 and hence in pipe 10 sure of the air entering the engine, a source of
25 and in the chamber 2li, to the point C, which
iiuid under pressure, a servomotor valve opera
would also be located on the normal curve.
tively connected to the barometric device and to
Meanwhile, the governor il maintains the speed
>the second governor so constructed and arranged
of the propeller constant at the speed determined
that it controls the now of said fluid under pres
by the position of the lever 30.
sure, a servomotor operatively associated with
If this point C is not on the desired normal
said servomotor valveand adapted to be operated
curve, it is corrected by changing the contour of
by said fluid under pressure and by said servo
the cam surface 2i.
When the cam l0 is moved
motor valve, a link connection from said servo
to the left counter-clockwise and the sleeve il
motor to said throttle lever adapted to move the
moves to the left at any given speed, the capsule so throttle so as to maintain the pressure in the air
23 is translated to the left, carrying With it the
entrance to the engine at the pressure required to
valve 2S, compressing the spring 34. Oil pressure
move the servomotor valve into its neutral posi
then ilows down the pipe 53, passage 54, the pis
ton 21 moves to the right, the link 60 moves to
2. A device as set forth in claim 1 in which
>the left carrying With it the ball 53. The throttle
there is a casing supporting said automatic mech
anism and in which second centrifugal governor
51 is then moved towards the wide open throttle
position, but the link 49 is not moved and there
fore, the revolutions per minute of the engine
is slidably mounted with respect to said casing,
means for sliding the second centrifugal gover
remain stationary and therefore, the point C
nor, the pressure responsive device and the servo
moves up to point D. The point D is vertically 30 motor valve laterally so as to vary the pressure
above the point C because the speed is constant
automatically maintained in the air entrance to
and the distance C-D corresponds to the dis
the engine with each speed of the engine.
tance between the tvvo curves, the better economy
3. A device as set forth in claim 1 in which
curve and the normal curve.
The capsule re
there are additional valve means so located that
sponds to changing pressures virtually on a 35 when open it renders the servomotor inoperative,
straight line; hence the cam l0 need be calibrated
manually controlled mechanism for said valve
for only tvvo positions.
mounted on said manually operated control de
The probable relationship is that point A cor
vice and so constructed and arranged as to be
responds to 23" mercury at 1500 R. P. M.; point
operated at vany position of said control device,
B corresponds to 22" mercury at 1700 R. P. M.; 40 a yieldable link connecting the throttle with the
point C corresponds to 26” mercury at 1700
manually operated device and adapted to man
R. P. M.; point D corresponds to 29" mercury at
ually control the throttle lever when said servo
1700 R. P. M.; point E corresponds to 40" mer
motor is inoperative,
cury at 2350 R. P. M.; and point F corresponds to
4. A device as set forth in claim 1 in which
45” mercury at 2350 R. P. M.
there are additional valve means so located that
What I claim is:
when open it renders the servomotor inoperative,
1. In combination With an internal combustion
a link connected to said valve and to said man
engine having an air entrance and a throttle
ually operated control device, a second link also
valve therein adapted to control the air ñoW to
connected to said manually operated device and
the air inlet of the engine, a variable pitch pro 50 so constructed and arranged as to push the throt
peller driven by said engine and an engine-driven,
tle lever into the closed position when the man
variable speed centrifugal governor for control
ually operated control device is set in the posi
ling the engine speed by varying the pitch of said’
tion of minimum speed of the engine so that the
propeller, a manually operated control device for
throttle may be easily closed Whenever the auto
said governor and connected to the variable speed 55 matic throttle control device is disconnected.
means of said governor so as to control the speed
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