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Nov. 26, 1946.
c. A. NEL'soN
2,41 1,747
Filed Aug. 31, 1944
___ _ _
'ClaudeANelsm BY Qfz’
Prasad Nome,
. 2,411,141
Claude A. Nelson, Wilmerdinß'Pa., assigner to
The Westinghouse Air Brake Company, Wil
merding, Pa.,- a corporation of Pennsylvania
Application August 31, 1944, Serial No. 552,024
z claims.
' '
4 opposite the strut head l. At the opposite or
right hand side of diaphragm 5, as viewed in the
drawing, is a chamber I3 which is open to atmos
This invention _relates to control devices and
,more particularly to fluid pressure controlled and
v operated motors.
‘ phere through a port I4 and winch contains a
One object of the invention _is the provision of
_an improved motor of the above type.
Fluid motors employed on airplanes for ad-v
justing various devices such as engine throttles,
follower- I5 engaging the adjacent‘face of said
diaphragm. The strut heads 8 and 8 and oppo
sitely arranged followers AI2 and I5 are secured
to the respective diaphragms by any suitable
mixture control devices etc. must be as small,
compact and light in weight as possible, and
-means or in any suitable manner, not shown
another object of the invention is the provision 10 in Athe
bore is provided centrally through the strut
of an improved fluid motor embodying these
head 8, follower I2 and the interposed portion
characteristics and therefore particularly adapt
of diaphragm 4, and slidably mounted in this
bore is a fluted stem I8. A fluid pressure supply
valve Il disposed in chamber I8 >is provided on
prises a power member which.A may be in the
end of the stem I6, while on the opposite end
form of a piston and which is adapted to be oper-`
of said stem, which terminates I'in chamber 8,
ated by fluid under pressure to effect .adjustment
there is provided a fluid pressure release valve I8.
of the device to which it may be operatively con
The follower I2 has a seat for engagement by
nected, and a pilot portion arranged for control
the supply valve I1, while a seat for the release
by fluid under pressure to control the pressure 20 valve I8 is provided on an arm I9, the seat ex
of fluid on the powe'r‘piston, and according to ~’
tending around one end of a bore 20 in said arm.
another feature of the invention a single pipe is
'I'he arm I8 is an integral part of the casing
employed for controlling the pilot portion of the
section 2 and extends into the space between the
motor and for supplying fluid under pressure to
strut heads 8 and 8. The opposite end of
the motor for actuating the power piston, thereby 25 two
bore 20 opens to a chamber 2| in arm I8 and
maintaining at a minimum the weight of the
said chamber is connected by a passage 22 to 9;/
system for controlling the motor.
fluid release pipe 23.
Other objects and advantages will be appar
The fluid release pipe 23 may lead-directly izoent from the following more detailed description 50 atmosphere, or it may be 'connected to' a sump
of the invention.
reservoir (not shown) employed for receiving
In the accompanying drawing, the single figure
fluid under pressure after it has been used to
is a longitudinal sectional view of a fluid motor '
ed, though not limited, for such use.
The fluid motor embodying the invention com-- V
embodying the invention.
The improved fluid motor comprises a casing
produce a desired operation. Fluid'under pres- v
sure thus released to the sump reservoir will then -
5 be recompres‘sed into a storage reservoir for use
again. Particularly on large airplanes where
many fluid motors will be used for controlling
different devices, pressure of fluid in the sump
l made up of sections' I, 2, >and 3 which are adapted
to be rigidly secured together inthe relationship
4 in which they are sho'wn i'n the drawing.` A flex
' reservoir may vary from. for instance, atmos
40 pheric pressure when no fluid pressureis being
released to the reservoir, to, momentarily, a‘rela
ible diaphragm 4 is clamped around its edge be
tween the casing sections I and 2, while a flex
ible diaphragm 5 is clamped around its edge be
tween the casing sections 2 land 3, said dia
tively high degree, such as thirty-five pounds,- if
fluid under pressure is released to said reservoir
from al1 of the controlling motors at the same
phragms being of the same areas and arranged l
45 time.
in coaxial relation.
In the present application it is merely de
sired to bring out however that, in practice, the
pressure of fluid in pipe 28 and thus in chamber-
Between the two diaphragms 4 and 5 is a cham
ber 6 containing a strut ‘I having at one end a
2l acting on the seating side of the release valve
head 8 engaging the adjacent face of diaphragm
I8 may be of any degree between atmospheric and _
certain higher pressure, suchy as thirty-'five
4, and having at the opposite end a head 9 en
gaging the adjacent face of diaphragm 5.
the opposite side of diaphragm 4 is a~ control
chamber I0 connected through a passage >Ilia to
pounds, as Just described. Nol further descrip
a combined, or common control and fluid pres- .,
sure supply pipe I I. Chamber I0 contains a fol
lower` I2 engaging the adjacent face of diaphragm
tion of the sump reservoir or its function is es
' sential in the present application, although if de
sired, reference may be made to the copending
55 application of Rankin J. Bush, Serial No. 480,161,
3 ,
ñled March 23, 1943, and assigned to the assignee
pipe will preferablybe in excess of atmospheric
pressure, for example it may be iifty pounds.
of the present application, which discloses a con
trol system embodying a sump reservoir, such as
above referred to.
The spring 40 is interposed between the dia--
phragm follower YI5 and power piston 29 under
A bore is provided through the casing section
I in coaxial relation to the supply valve I1, and
secured to saidcasing section over the outer end
such adegree of pressure that, with the `piston 29
in a. normal position deñned by contact with a .
stop 42 in casing section 3, the pressure of said
spring on the diaphragm follower I5 will hold the
ed in this >bore is a sleeve 25 extending into con
diaphragms 4 and 5 against the opposing con
trol chamber I0 and having a closed end which 10 trol pipe pressure (50 pounds) in chamber I0 in
engages the supply valve I1. A coil springv 2B
a position in which the supply valve I1 will be
of said bore is a, hollow cap 24. Slidably mount- Y
-mounted .in sleeve 25 and having one end bearing
seated and the release valve I8 will also be seated ‘
againstl the closed end of said sleeve, extends into
or slightly open.
cap .24. The opposite end of spring 26 bears
The spring 40 is connected to the powerpiston
against cap 24. 'I‘his spring is under pressure 15 29 to renderl said piston effective to control, Ü
and acts on the supply valve I1 with only suffl- ‘
through said spring, certain operation of the
cient force to ensure seating of said valve against
diaphragms 4 and 5 and valves'll and I8, as will
the follower plate I2 or seating of the release
be l"later described, but it will be noted that said
valve I8 against its seat.A
spring is .also effective _to urge piston 29 in the
Within the cap 24, the sleeve 25 is provided
direction of stop 42. The spring 39,15 confined
with an annular collar 21 for contact with the
under pressure between the shelf 4I -and piston
. casing section I when said ycasing section is re
29 and its sole function is to urge the piston 29
moved from the section 2, so- as to hold the spring
into contact with stop 42 >upon reducing pressure
26 and sleeve 25 assembled within the casing
of iiuid in chamber „30, as will be later described.
section I, under such a condition.
It will be understood that the spring 39 is re
-The casing section 3 has- a bore 28-formed in
quired to coact with spring 40 to move piston 29
coaxial relation with the diaphragms 4 and 5 and
in the direction of and into contact with stop 42
containing a power movable abutment which may
only _in case the resistance to such movement
be in the form of a piston 29. The chamber I3
exceeds the pressure of spring 43, as may bethe
is provided at one side'of piston 29 whereby said 30 case where piston 29 is of relatively large area,
piston is constantly subject on this one side to l or where a Arelatively great force> is required t0
atmospheric pressure. At the opposite side of
operate lever 35 and the device which may be
piston 29 is a power or operating pressure cham
connected to said lever. If the force opposing
ber 30 which is -in constant communication
movement of piston 29 in the direction of stop
through passage 3I with chamber 6 formed be
tween the two diaphragms 4 and 5.
35 42 were suiiiciently great, the pressure of spring
The piston 29 has a stem 32 extending through
chamber 30 and a bore in the casing section 3
40 on said piston might be of negligible value in
obtaining such movement. However, if the force
opposing movement pf piston 29 in the direction
to the exterior thereof. A resilient ring 33 car
of and into contact with stop 42 does not ex
ried in an annular groove in casing section 3 has 40 ceed the forceof spring 40, then the spring 39
sealing and sliding contact with the portion of
' might be dispensed with.
the piston stem within the bore in said casing
Thearea of' piston 29 'is such as to render it
section to prevent leakage of ñuid under pressure
effective to rock lever 35 to operate the con
from chamber 3l) around said stem to atmos
nected device (not shown) against the opposing
pressure of spring,40 or of both springs 39 and
The outer end of the piston stem 32 is con
40 by a lower pressure vof iiuid in chamber 30
nected by a pin 34 to a lever 35 at a point between
Y than is required inchamber I0 on diaphragm
the ends of said lever. One end of lever 35 is
4 to move said diaphragm. the str_ut 1 and dia-v
connected by a pin 36 to a fulcrum link 31
phragm’5 against spring 40. The diameter of
mounted t6 turnon a pin 31a carried in the 50 piston 29 willr therefore depend upon the load
casing section 3. In the opposite end of lever 35
which it is required to operate and may be even
is a hole 39 for receiving a pin (not shownyto
greater than shown in the drawing.
connect said lever, and thereby the power piston
29, to a device which it is desired to operate.
In chamber I3 are two concentrically arranged
coil springs 39 and 40 both _of which bear at one
end against the piston 29. The opposite end of
spring 39 is supported on a shelf 4I >projecting
from casing section 3 into chamber I3. The
opposite end of spring 49, which may be called 60
a regulating spring, bears against the diaphragm
As above mentioned, pipe I I constitutes a com
bined control and nuid pressure supply pipe, that
is to say constitutes a control pipe for controlling
operation of> the `diaphragms 4 and 5 and thereby`
the supply valve I1 and release valve I3, which
parts constitute a pilot portion ofthe motor, and
Let it' initially be assumed that the control
pipe II and control chamber I0 are~ charged with '
fluid at the minimum pressure of fifty pounds
above mentioned. Under this condition, the parts
of the motor will assume the positions in which «.
they are shown in the drawing, as will -be appar- '
ent from the foregoing description.
If the pressure of iiùid in pipe II and in cham
ber _III is now increased, this increased pressurev
effective on diaphram 4 will overcome the oppos
ing force of control spring 40 and move the dia
phragms 4, 5 and strut '1, and followers I2 and
I5 and the adjacent end of said spring> in unison
„against the opposing force of said spring and rel
also constitutes a iluid pressure supply pipe, or
ative to the opposite end of said spring `rand pis
a source of fluid under pressure, from which ñuid
70 ton 29. If the release valve I8 is not seated when
under pressure is obtained for controlling op
the pressure in chamber I 0 is at thenormal de'
eration of the power piston 29, in a manner which
will be later described. Due to pipe II constitut
gree, the initial deflection of the diaphragms will
permit seating of said valve under the action of
ing a source of ñuid under pressure as just men
spring 25. With the release valve I8 seated, how
tioned, the normal or minimum pressure in said 75 ever, said valve will hold the supply »valve I1
' 9,411,741
chamber vI 9. as
against movement with the diaphragms, so
upon further dcilection of the diaphragme the
seat for said supply valve on follower I2 will be
moved away from the supply valve.
` Upon opening of _the supply valve Il as :lust de
scribed, fluid under pressure supplied to chamber
be _evident from the above de
'In the operation lust described, the piston 29,
due to thefaction of spring 49, may or may not
move in unison with the'diaphragms 4, 9 as they? .i '
_' are operated to openïthe supplyy valve I1, depend
ing upon the resistance to movement of the de
I9 from the control pipe II, which pipe consti
vice (not shown) which is operated by lever Il.
tutes a supply source of iluid under pressure, will
If this resistance is sufilciently great the piston
then flow past the supply valve to chamber 9 and
10 29 may remain stationary when the diaphragms
thence through passage 3| to chamber 39.
-`When the pressure of fluid supplied to cham- ' _ 4, 9 operate to open the supply valve Il, but if ‘
sufllciently small, said 'piston may move with said _
diaphragm to open the supply valve. If the pis
to a degree sufficient-to overcomespring 49 or of,
both springs 99 and 49, as the case may be, and ¿'ton 29 does‘not move with the diaphragms 4, 5 A
to open the supply valve I1, it will-be immaterial
to also actuate lever 35 to operate the device be
however, _since- as little. as one one-thousandth '
ing controlled, said piston will move against the
opposing force of said spring or springs, and such Y» of an -inch movement will open said valve to sup-v
ber 39, and acting on piston 29 is then increased
movement will act to increase the force of spring
49 opposing the pressure of fluid in chamber I9
ply fluid under-*pressure to chamber 39'tostop
A such movement of said piston. Moreover, this
20 small amount of movement of piston 29 would.
on diaphragm 4.
have substantially no eiîect upon the >device con-.
-Now assuming that the increase in pressure of
nected to lever 3S, and said piston will be prompt- ' .
fluid in chamber I9, eñ‘ective on diaphragm 4, is
operated by the ñuid under pressure supplied '
limited to some degree lower than maximum pres
to chamber 39 to the position corresponding to
sure, then when the pressure of spring 49 is in
creased, by movement oi? piston 29, to'a degree 25 the increase in pressure in chamber. I9, as above
described.sufllcient to overcome the opposing force of said
It will now be seen that the piston 29 can bev
pressure of ñuid 'in chamber I9, said spring will
caused to~ ,move from the normal position, Íin
be operated by said piston to move the dia
which it is shown in the drawing, to any selected
phragms and followers in the direction of the
open supply valve I'l and finally move the fol 30 position at the left hand side of normal position
vvby providing the proper pressure of fluid in cham-»
lower I2 into seating engagement with said valve.
ber I9 in excess- of the normal or minimum pres
When the supply valve is thus closed, further flow
of fluid under pressure will be prevented to cham
'With the piston 29 moved ’awayfrom stop 42,
ber 99 and, as a result, movement of the piston
29 will cease. When the piston 29 stops moving, 35 due to the pressure or fluid lin chamber I9 having
been increased as above described, let it be as
the spring 49 becomes static and movement of the
sumed that it is desired to move said piston back
diaphragms will also cease ina position in which
in the direction of said stop. To accomplish this,
the release valve will be still seated, whereby the
fluid under pressure will be bottled in chamber
the pressure of iluid in chamber I9 will be reduced
the power piston 29 moves to a position deter
mined by and corresponding to the degree of in
in the direction of chamber I9. This movement
of the diaphragms and thereby of the seatedV sup
ply valve I'I will act through the stem I6 to pull
the release valve I8 out of contact with its seat,
39 to maintain the piston 29 and~ lever 35 against 40 to destroy the equilibrium between its effect on
diaphragm 4 and the opposing pressure of spring
49. Spring 49 will then deflect the diaphragms
From the above description it will be noted that
crease in pressure of fluid in chamber I9 above
the normal orminimum pressure, and it; will be
further noted that this movement of the power . f whereupon fluid under’pressure will be released
piston, while opposed by springs 39 and 49, is de
pendent upon a sumcient increase in pressure in
chamber _39 to actuate the lever 35 and the device
which may be connected to said lever. Thus a
relatively low pressure of fluid in chamber 39 may
be adequate to operate the piston 29 at one time
or under a certain condition, while a higher pres
sure of fluid will be required to cause the same
movement of said piston at another time or un
der a different condition. The area of piston 29
is such however that under all conditions it will
from chamber 39-through passage 3i, chamber 6
and past said release valve~to chamber 2| and
thence through passage 22 to release pipe 23. The
consequent reduction in the pressure of fluid in
chamber 39 will then permit movement of' pis
ton 29 by spring 49 or springs 39 and 49 in the
direction of stop 42, it being noted that such
- movement will allow expansion of spring 49 and
thus a reduction in the force it exerts againstJ the
Assuming that the pressure of fluid in cham
ber I9 is not reduced to its normal degree, then
' be moved against spring 49, by fluid in chamber
39 ‘at a, lower pressure than is present in cham 60 as soon as the pressure of spring 49 becomes re
duced, as just described, to a degree which sub- ,
ber I9, and in pipe i I which constitutes the source
of supply of fluid under pressure for operating
said piston.
Now let it be assumed that the pressure of fluid l
stantially equals the force on diaphragm 4 pro
vided by the pressure of fluid in chamber I9,- the
diaphragms and valves will be moved in unison
in chamber I9 isincreased to a higher degree 65 by pressure of iluid in said chamber and cause
the release valve I9 to move toward its seat and
than above considered. Upon such an increase
finally into contact with its seat in a. position of
the diaphragms 4, 5 will again be deflected against
piston 29 in which the reduced pressure off spring
the opposing force of spring 49 to reopen the sup
49 substantially equals theforce developed by the
ply valve Il for supplying more fluid under pres
sure to chamber 39. The piston 29 will then 70 reduced pressure of fluid in chamber I9 acting
again move against the opposing force of spring
, on the diaphragm 4. -When the release valve is
49 or of_ springs 39’and 49 and cause operation
thus closed further release of fluid under pressure
from chamber 30 will stop and piston 29 willv
of the diaphragms _to again close the supply
-thenstop moving in a position corresponding to
valve'in a new position of said piston, correspond
ing again to the increasein pressure fluid 'in 75 the degree of reduction in pressure of fluid in
2,41 1,747:
chamber iii, or in other words, corresponding to
sure controlled pilot portion for controlling the
the pressure in said chamber in excess of_ the'nor
mal minimum pressure.
In the operation just described, the piston 29
power portion, and a single or common pipe
serves> asl a control pipe for the pilot portion
and as a fluid pressure supply pipe, or as a source
may, or may not, move in unison _with diaphragms 5 'of fiiiid under pressure, for controlling operation
4 and 5 in response to a reduction in pressure of
iiuid in chamber i0, depending upon the resist
of the power portion. v
chamber I0, the motor will again operate, as just
sides ofsaid power andpilot means in opposi
Having now described my invention, what I
claim as and desire to secureby letters Patent, is:
ance to movement of the device (not shown) con
1. A 'lluid motor comprising a casing, power
nected to lever 3_5, as will be obvious from the,A
above description of operation of the device in 10. means in said casing subject on. one side to pres»
response to an increase in pressure of ñuid in
sure of fluid in a power chamber, pilot means in
saidcasing arranged in coaxial relation to said
chamber i0. Regardless of this, however, the
power means and subject on the opposite side to
piston 29 will be moved to a position correspond
lng to the pressure of i‘luid in chamber I0 upon a , pressure of fluid in a control chamber connected
15 to a iluid pressure supply and control passage.
reduction in such pressure, as above described.
a coil spring in said casing acting on adjacent
Upon a further reduction in pressure of iiuid in
tion to pressure of ï iluid in the respective said
described, to cause a corresponding change in po
chambers, valve means controlled by said pilot
sition of piston 29. If the pressure of ñuid -in
chamber I0 is reduced to the normal degree, the 20 means for controlling communication between
said passage and a third chamber at the opposite
e piston 29 will be moved by spring 39 or springs
39 and d0 to its normal position in which it is
side of said pilot means,‘means opening said
shown in the drawing. Before the release valve - third chamber to said power chamber. said valve
means also controlling a communication between
I8 seats or it may seat at the instant said pis
ton engages stop 42. In either case, a complete v25 said third chamber, and thereby said power
chamber, and atmosphere, said pilot means being
return of the piston 29 to its normal position will
be obtained.
If as just mentioned the release valve I8 is
seated at the time piston 29 contacts stop 42, the
pilot diaphragm 4 will be conditioned to operate 30
in said control chamber to effect operation of said
valve means to open communication between said
to more quickly open the supply valve I1 upon a
erable upon -a reduction» of pressure of ñuid in
said control vchamber to open said third chamber
subsequent increase in pressure in chamber l0,
bottle up fluid ir said chamber at a pressure in
suiiicient however to move piston 29 out of con
35 third chamber on said pilot means and render
ing the adjacent side of ,said power means subject
tact with said stop. This bottled pressure how
ever will render piston 29 more quickly respon
to atmospheric pressure.
2. A ñuid motor comprising a casing, power
sive to a subsequent supply o1' iluid under pres
valve I1, as will be readily apparent.
passage and_said third chamber 'and being op
to atmosphere, and lmeans_in said casing counter
acting the action of fluid pressure'in the said
also, the closing of said valve at this time may
sure to said chamber by opening. of thesupply
operable upon an increase in pressure of ñuid
means in `said casing subject on one side to pres
. 40 sure of fluid in a power chamber, pilot means in
It will now be seen' that the power piston 29
can be caused to move toward and to be stopped,
isaid casing arranged in coaxial relation to said
'power means and subject on the opposite side
in any selected position out of its normal «pesi-Y ‘ to pressure of fluid in a control chamber, a coil
spring in said casing acting against adjacent
tion by reducing the pressure fluid in chamber IUI
to the proper selected degree, or the fullvand un’ 45 sides of said power and pilot means in opposi
tion to pressure of fluid in the‘respective said
interrupted return to normal position may'be ob'
chambers, valve means in said casing controlled
tained, if desired, by a continuous reduction in
by said power and pilot means and operable
pressure of fluid inìchamber Il) to'the normal
by said pilot means upon an increase in pressure
minimum pressure.
of fluid in said control chamber to supply iluid
It will be noted that the pressure of ñuid in
to a third -chamber at the opposite side of said
chamber 39 also acts in chamber `6 at all times
pilot means and operable upon a'reduction in
but has substantially no influence upon the'above
pressure of ñuid in said control chamber to
described operation of the pilot portion of the~
motor due to its action on one diaphragm being
release ñuid under pressure from said third cham
counteracted by its effect on the other diaphragm. 55 ber, means providing a constantly open com
munication between said third chamber and said
In case pipe 23 is connected to a sump reser
_power chamber, said power means being- operable
voir, as hereinbefore mentioned, it will be seen
either against or by said spring means, to a posi->
that the pressure cf'ffiuid in chamber 30 can
tion corresponding to the increase or reduction
only be reduced as above described, to the pres
in pressure of_ fluid in said control chamber, to.
sure effective in said reservoir. The pressure
effect operation of said valve means to bottle
of springs 39 and 49 is such however as to insure
the iiuid pressure in said third and power cham
movement of the piston 29 into contact with Istop
bers, the pressure of fluid in said third chamber
42 against the maximum pressure which may be
being effective on said pilot means in opposition
eiïective in the sump reservoir and in chamber 39.
65 to pressure of fluid in said-control chamber, and
means operable by pressure of 'iluid in said third
It will now be apparent that I have provided
chamber to counteract the effect of the pressure
a power motor which is relatively simple and com
of fluid in said third chamber on said pilot means
pact and which may be relatively small and ._ and also rendering the adjacent side oi.' said
light in weight, for the purpose intended. The o power means subject to atmospheric pressure.
motor comprises a power portion which is op
erable by ñuld under pressure, and a iluid pres
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