U.S. patent number 3,683,749 [Application Number 05/043,325] was granted by the patent office on 1972-08-15 for hydraulic control means.
This patent grant is currently assigned to LTV Electrosystems, Inc.. Invention is credited to Fred R. Bayles.
United States Patent |
3,683,749 |
Bayles |
August 15, 1972 |
**Please see images for:
( Certificate of Correction ) ** |
HYDRAULIC CONTROL MEANS
Abstract
A hydraulic control device for controlling the operation of a
reversible hydraulic motor device, such as a hydraulic ram, which
has a deactivating valve assembly which provides a fluid bypass
passage across the fluid inlet and passages of the ram cylinder to
render the hydraulic ram inoperative in the event of malfunction of
the control device. An apparatus for operating a controlled member,
such an aileron, spoiler or the like, of an aircraft which includes
a plurality of hydraulic motor devices having separate control
means for individually controlling the motor devices, the control
devices having means for deactivating the motor devices upon the
malfunction of the control devices so that the motor device whose
control device has malfunctioned or is inoperative will not impede
the operation of the controlled member by the other motor devices
whose control devices still function properly.
Inventors: |
Bayles; Fred R. (Dallas,
TX) |
Assignee: |
LTV Electrosystems, Inc.
(Dallas, TX)
|
Family
ID: |
21926588 |
Appl.
No.: |
05/043,325 |
Filed: |
June 4, 1970 |
Current U.S.
Class: |
91/438; 91/1;
91/509; 244/99.5 |
Current CPC
Class: |
B64C
13/24 (20130101); F15B 18/00 (20130101) |
Current International
Class: |
B64C
13/00 (20060101); B64C 13/24 (20060101); F15B
18/00 (20060101); F15b 011/16 () |
Field of
Search: |
;91/438,439,1 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Geoghegan; Edgar W.
Claims
What is claimed and desired to be secured by Letters Patent is:
1. A control device for controlling operation of a hydraulic motor
device having first and second passage means and operating in one
direction when fluid under pressure is allowed to flow to one of
the passage means and exhaust from the other and operating in an
opposite direction to said one direction when fluid under pressure
is allowed to flow to said other passage means and exhaust from
said one of the passage means, and being prevented from operating
in either direction when fluid flow through both passage means is
prevented, said control device including: body means having inlet
means connectible to a source of fluid under pressure and fluid
outlet means; a control valve assembly for selectively transmitting
fluid under pressure from said inlet means to one of said flow
passages of a hydraulic motor device permitting flow of fluid from
the motor device from its other flow passage means to said outlet
means, and preventing flow through both of said flow passage means,
and a deactivating valve assembly operatively associated with said
control valve assembly and said motor device responsive to the
malfunction of said control valve assembly for providing a bypass
flow passage between said passage means of the motor device upon
malfunction of the control valve assembly, said body means having
first and second passages in communication with said first and
second flow passage means of said motor device, and a valve member
movable in said body means for selectively placing said first and
second flow passages in communication with said inlet and outlet
means and preventing fluid flow between said first and second flow
passages; said control valve assembly including a control member
operatively associated with and movable relative to said valve
member, and piston means operatively associated with said control
member and said valve member and biased by hydraulic pressure from
said inlet means for exerting a force on said valve member tending
to cause said valve member to move with said control member, said
control member and said valve member having passage means
communicating said inlet means with said deactivating valve
assembly upon movement of said control member relative to said
valve member to actuate said deactivating valve assembly when the
movement of said valve member is resisted by a force greater than
the force exerted thereon by said piston means.
2. The control device of claim 1, wherein said valve member
comprises a tubular valve spool having a central longitudinal bore
therein and said control member includes a rod longitudinally
slidable in said bore of said valve spool, said piston means
comprising a pair of longitudinally spaced tubular pistons, said
pistons and said valve spool and said control member having
co-engageable means limiting longitudinal movement of said piston
means relative to said control member and said valve spool.
3. The control device of claim 2, wherein said co-engageable means
permit limited longitudinal movement of said pistons relative to
said valve spool and said rod.
4. The control device of claim 3, and means responsive to the
actuation of said deactivating valve assembly for providing a
signal at a location remote from said control device.
5. The control device of claim 1, and means responsive to the
actuation of said deactivating valve assembly for providing a
signal at a location remote from said control device.
Description
This invention relates to hydraulic control devices and to
hydraulic apparatus for controlling the operation of a plurality of
hydraulic motor devices used to operate a controlled member.
An object of the invention os to provide a new and improved
hydraulic control device for controlling the operation of a
hydraulic motor device.
Another object is to provide a hydraulic control device for a
reversible hydraulic motor means which is caused to operate in one
direction when hydraulic fluid under pressure from a hydraulic
pressure system is circulated thereto in one direction and to
operate in the opposite direction when the hydraulic fluid is
circulated thereto in a second direction, and which is held against
operation in either direction when the circulation of hydraulic
fluid to or from the motor means is prevented.
Still another object is to provide a hydraulic control device, of
the type described, having a control valve assembly which is
operable selectively to admit fluid under pressure to a first or
second fluid passage means of a hydraulic motor means and permit
exhaust of hydraulic fluid from the other of the first and second
flow passage means, or to prevent flow of hydraulic fluid to or
from either of the first and second flow passage means of the
hydraulic motor means; and a deactivating valve assembly which is
responsive to malfunction of the control valve assembly for
providing a first bypass flow passage between the first and second
flow passage means of the motor control hydraulic motor means to
deactivate the motor means and permit a controlled member normally
operated by the motor means to be moved by other forces.
A further object is to provide a hydraulic control device, of the
type described, which also has a bypass valve assembly, operatively
associated with the control valve assembly and operable when the
hydraulic pressure source or system fails to provide hydraulic
fluid under predetermined pressure to the hydraulic control device,
for establishing a second bypass flow passage between the first and
second passage means of the hydraulic motor means.
A further object is to provide a new and improved hydraulic control
device for controlling the operation of a hydraulic ram having a
piston reciprocable in a cylinder and first and second passage
means at opposite side ends of the cylinder and opening to the
cylinder on opposite sides of the piston, the control device being
operable selectively to admit hydraulic fluid under pressure to
either of the passage means and permit exhaust of the fluid from
the other of the passage means, in order to cause movement of the
piston in one or other direction in the cylinder, and to prevent
flow of hydraulic fluid to or from both of the passage means to
prevent flow of hydraulic fluid to or from either end of the
cylinder through the passage means whereby the piston is
effectively locked in any adjusted position thereof relative to the
cylinder, the control device including a deactivating valve
assembly which is operable by fluid pressure upon the malfunction
of the control valve assembly to provide a first bypass flow
passage between the opposite ends of the cylinder whereby the
piston is freed for movement in either direction in the
cylinder.
A still further object is to provide a hydraulic control device of
the type described wherein the control valve assembly includes a
valve member or spool longitudinally movable in a body means of the
control device by means of a reciprocable control member or rod by
pistons exposed to hydraulic pressure which exert predetermined
forces on the valve spool to cause the valve spool to move with the
control rod, the control rod being movable relative to the valve
spool if the valve spool is held against movement by a force which
exceeds the predetermined value, the control rod and the valve
spool having cooperative means for providing hydraulic fluid under
pressure to the deactivating valve assembly upon occurence of
relative movement between the control rod and the valve spool.
An important object of the invention is to provide a hydraulic
apparatus or system for controlling operation of a plurality of
hydraulic motor devices used jointly to operate a controlled member
which apparatus employs separate control devices for individually
controlling operation of the individual motor devices.
Another object is to provide a hydraulic apparatus or system, of
the type described, wherein each control device has means for
deactivating the motor device controlled thereby upon the
malfunction of the control device in order that a motor device
whose associated control device has malfunctioned or is inoperative
will not impede or hinder the operation of the controlled device by
the other motor devices whose control devices are functioning
properly.
Additional objects and advantages of the invention will be readily
apparent from the reading of the following description of a device
constructed in accordance with the invention, and reference to the
accompanying drawings thereof, wherein:
FIG. 1 is a sectional partly schematic view, with some parts such
as seal means omitted for clarity of illustration, of the hydraulic
control device embodying the invention for operating a hydraulic
ram and showing the control device in position preventing flow of
fluid from either end of the cylinder and causing the piston of the
hydraulic ram to be held against movement by the hydraulic
fluid;
FIG. 2 is a view similar to FIG. 1 showing the valve spool of the
control valve assembly of the device held against movement in the
body means of the device and its control rod displaced to the right
relative to the valve spool, and the deactivating valve assembly
being in actuated position and providing a bypass passage between
opposite ends of the cylinder of the hydraulic ram;
FIG. 3 is a view similar to FIG. 2 showing the control rod
displaced to the left relative to the valve spool and the
deactivating valve assembly in actuated position; and,
FIG. 4 is a fragmentary perspective view, with some parts broken
away, showing the control devices embodying the invention in use
for controlling separate hydraulic rams for actuating a controlled
member, such as the illustrated aileron on an aircraft.
Referring now to the drawings, each hydraulic control device 10
embodying the invention is shown as used to control the operation
of a hydraulic motor. Two or more such motors 11 and 11a, FIG. 4,
individually controlled by separate devices 10 and 10a,
respectively, are shown in use to operate a control member of an
aircraft, such as an elevator 12, spoiler or the like. The
hydraulic motors are of the hydraulic ram type having cylinders 14
in which are reciprocable pistons 15 whose rods are pivotally
connected by means of clevises 16 and pins 17 to levers 18 rigidly
connected to a rotatable shaft 19 to which the control member is
rigidly secured. The pins 17 extend through suitable slots 20 of
the levers.
It is desirable and necessary in the event of a malfunction of a
control device 10 of one of the motors, that such motor be
deactivated or rendered inoperative so that it will not interfere
with the operation of the aircraft control member by the other
motor or motors whose control devices are still in operative
condition.
Each of the control assemblies includes a control valve assembly
CVA, operable by the usual auto pilot and a pilot manual override
control of an aircraft, not shown, which selectively causes
hydraulic fluid under pressure, from the hydraulic fluid
circulating system of the aircraft, to be admitted into one end or
the other end of the hydraulic cylinder 14 while allowing flow of
the hydraulic fluid from the other end of the cylinder back to the
fluid return line of hydraulic system when the valve assembly is in
either of its opposite operating conditions and which prevents flow
of hydraulic fluid from either end of the hydraulic cylinder when
the valve assembly CVA is in its neutral or intermediate position;
a bypass valve assembly BV which isolates the control valve
assembly CVA from the pressure side of the aircraft hydraulic
system when the pressure of the hydraulic fluid is below a
predetermined value; and a deactivating valve assembly DVA which,
when the control valve assembly is damaged or malfunctioning,
provides fluid communication between opposite ends of the hydraulic
ram cylinder 14 so that the piston is free to move within the
cylinder.
Each of the control assemblies 10 includes a housing 25 having a
chamber 26 which is closed at one end by a closure 17. A control
shaft 28 suitably journaled in opposite walls of the housing
extends through the chamber 26. The control shaft is rotatable
about its central longitudinal axis, being connected at a location
externally of the housing to the autopilot linkage and also to the
pilot manual override control. The control shaft has rigidly
secured thereto an arm 30 whose outer end is bifurcated to provide
a pair of legs 31 which are disposed in an external annular recess
32 of a reciprocable control rod 33. It will be apparent that when
the control shaft 28 is rotated in a counter-clockwise direction
through a limited angle, the engagement of the cam surfaces 35 of
the legs 31 with the annular shoulder 36 of the control rod
defining one end of the annular recess 32 of the control rod causes
the control rod to move to the right and that when it is pivoted in
a counter-clockwise direction the engagement of the cam shoulders
37 of the legs with the annular shoulder 38 of the control rod
defining the other end of the annular recess 32 causes the rod to
be moved to the left.
The control rod 33 extends through a tubular valve spool 39
slidably mounted in a tubular valve body 40 disposed in a
longitudinal passage 41 of the valve body which extends
perpendicularly to the axis of rotation of the control shaft 28.
The valve body is held in proper position in the passage 41 by a
nut 42, threaded in the enlarged portion 43 of the passage 41,
whose inner surface bears against the outer end surface 44 of the
valve body and holds the inner annular surface 45 of the external
annular flange 46 of the valve body against the annular stop
shoulder 47 of the housing.
The valve body is provided with a pair of internal annular grooves
51 and 52 which are aligned with the external annular grooves 53
and 54, respectively, of the valve spool 39. The aligned pairs of
grooves 51 and 53 and 52 and 54 define annular hydraulic fluid
return passages R1 and R2, respectively. The hydraulic fluid return
line or conduit 54a of the hydraulic system of the aircraft is
connected to the housing 25 and opens to the internal annular
groove 56 of the housing which is aligned with and in communication
with an external annular groove 57 of the valve body 40. The groove
57 is maintained at all times in communication with the fluid
return passage R2 by a port 60 of the tubular valve body 40 which
opens to its external and internal grooves 57 and 52,
respectively.
The housing is also provided with a longitudinal passage 62 which
opens at its right end to the internal groove rt of the housing 25
and at its left end to a similar external groove 64 of the housing
which is aligned with and therefore in communication with an
external annular groove 65 of the valve body 40. A port 67 of the
valve body provides communication between the return passage R1 and
the groove 65 as it opens to the grooves 65 and 53.
The fluid return passages R1 and R2 are thus at all times connected
to the exhaust line 54a of the hydraulic system. The tubular valve
spool 39, intermediate its external recesses 53 and 54, is provided
with an external annular recess or groove 70 which defines with the
valve body an annular pressure passage P to which hydraulic fluid
under pressure is transmitted from the pressure line 72 of the
hydraulic system of the aircraft through the by-pass valve assembly
BV when the piston 75 of the by-pass assembly BV is in the actuated
position illustrated in FIG. 1 and held therein by the pressure of
the hydraulic fluid against the resistance of the spring 76. The
piston 75 is slidable in a tubular valve body 78 which is held in a
longitudinal passage 79 of the housing 25 by cap 80 threaded in the
external enlarged portion 81 of the passage. The internal annular
end surface 82 of the cap engages the external end surface 83 of
the valve body to hold the valve body against outward movement in
the passage. Inward movement of the valve body in the passage 79 is
limited by the engagement of its external end flange 34a with the
annular surface 84 of the valve body defining the inner end of the
enlarged portion of the passage 79. The flange 84a is provided with
a diametric slot 86 which is in communication with a port 58 of the
housing 25 which opens to the internal groove 56 thereof. As a
result of the provision of this slot 86 and the port 58, the bore
90 of the retainer cap 80 is at all times in communication with the
fluid return passage R2 and therefore with the hydraulic fluid
exhaust line 54 of the hydraulic system.
The spring 76 which biases the piston 75 toward its non-actuated
position has an end portion telescoped over the spring guide 91 of
the cap 80, the outer end portion of the spring engaging the
annular surface 92 of the cap 80 and its other end telescoping over
the spring retainer extension 94 of the piston and engaging the
annular shoulder 95 provided by an external annular flange 96 of
the piston.
The piston 75 is provided with an external annular recess 101
which, when the piston is in the actuated position illustrated in
FIG. 1, provides communication between the pressure fluid conduit
72 and the pressure passage P since the fluid pressure conduit 72
is connected to the housing 25 and opens to an internal annular
groove 104 of the housing in the passage 79 which is aligned with
and therefore in communication with an external annular groove 105
of the valve body 78. The groove 105 is in communication with the
internal bore or passage 106 of the tubular valve body through the
ports 107. The pressure passage P is in communication with passage
defined by the external recess 101 of the piston 106 through ports
108 of the valve body which open to the passage P and to an annular
recess or groove 110 of the valve body 40 which is aligned with an
annular groove 111 of the housing, a passage 112 which opens to the
groove 111 and 114 of the housing, an external groove 115 of the
valve body 78 which is aligned with the recess 114 and the ports
116 of the valve body 78 which open to the groove 115 and the
internal passage or bore 106 of the valve body 78.
The hydraulic pressure conduit 72 is in fluid communication with
the extreme left end portion of the passage or bore 106 of the
valve body 78 by means of a branch duct 118 which is connected to
the housing 25 at its bore 119 and which opens to the space 120
between the internal annular surface 121 of the housing defining
the inner end of the passage 79 and the inner end of the valve body
78.
When the pressure of the fluid of the hydraulic system of the
aircraft exceeds a pre-determined value, the force exerted thereby
against the inner end of the piston 75 is sufficient to overcome
the resistance of the spring 76 and the piston is moved to and held
in its actuated position illustrated in FIG. 1.
The piston 75 also has a second external annular recess or groove
125 which, when the piston moves to the left to its non-actuated
position, indicated in broken lines in FIG. 1, provides fluid
communication between two sets of ports 126 and 127, for a purpose
to be described below, which open to the external annular recesses
128 and 129, respectively, of the valve body 78 aligned with the
passages 130 and 131, respectively, of the housing and within the
passage or bore 79 thereof. The groove or recess 130 is in fluid
communication with a groove 132 of the housing by a passage 133
thereof and the groove 131 is in fluid communication with the
groove 135 of the housing by a passage 136 for a purpose to be
described below.
The grooves 132 and 135 are aligned with external annular grooves
141 and 142, respectively, of the valve body 40 and define
therewith annular control passages C1 and C2, respectively.
The control passage C1 is always in fluid communication with the
rear end of the cylinder 14 of the motor device 11 through a port
145 which extends between the annular recesses 146 and 147 of the
housing which are aligned respectively with the recess 141 of the
housing 25 and an external annular groove 148 of the valve body 150
of the deactivating valve assembly DVA, and a conduit 151 which
opens to the groove 147 and the rear end of the ram cylinder
14.
Similarly, the control passage C2 is always in communication with
the front end of the cylinder 14 by means of a port 153 which
extends between the annular grooves or recesses 142 and 154 of the
housing and a conduit 155 which opens to the annular groove 154.
The valve body 150 has an annular groove 156 aligned with the
groove 154.
The housing 25 has a plurality of ports 160 which open to the
groove 141 of the valve body 40. The ports 160 are closed by an
annular land 161 of the valve spool 39 when the valve spool is in
the intermediate position illustrated in FIG. 1, the land sealingly
engaging with the intermediate seal surface 164 of the valve body
40 to close the ports 160.
The valve body 40 has similar ports 165 which open to the annular
recess 142 of the valve body 40 and which are closed by the land
166 of the valve spool. When the valve spool is in the intermediate
position illustrated in FIG. 1 of the drawing, the land sealingly
engages the seal surface 164 of the valve body to close the ports
165.
It will now be apparent that if the valve spool 39 is moved to the
right relative to the valve body 40, as to the broken line position
indicated in FIG. 4, the control passage C1 is placed in fluid
communication with the fluid return passage R1 since its ports 161
will now open to the recess 53 of the valve spool and thus the rear
end of the cylinder 14 is placed in communication with the exhaust
duct 54 of the aircraft hydraulic system. Simultaneously, the
control passage C2 will be placed in communication with the
pressure passage P since its ports 165 will now be in communication
with the external recess 70 of the spool and therefore the
hydraulic fluid under pressure is simultaneously allowed to flow
into the front end of the hydraulic cylinder 14. As a result, the
piston 15 will be moved to its retracted position thus pivoting the
control led member 12 in a clockwise direction about the axis of
its shaft 19.
Conversely, if the valve spool 39 is moved to the left, as to the
broken line position indicated in FIG. 3, relative to the valve
body 40, the control passage C1 is placed in communication with the
fluid return passage R2. Fluid under pressure is now admitted to
the rear end of the cylinder from the pressure supply duct 72 of
the hydraulic system and simultaneously the front end of the ram
cylinder is connected to the exhaust duct 54 since the passage C1
is now placed in communication with the pressure passage P through
its ports 161 and the control passage C2 is placed in communication
with the fluid return passage R 2 through its ports 165. As a
result, the piston 15 is moved toward its extended position and
pivots the control member 12 in a counter-clockwise direction about
the axis of its shaft 19.
The valve spool, during normal operation of the control valve
assembly CVA is caused to move longitudinally with the control rod
33 by the force of the fluid pressure from the pressure passage P
which acts on the outer end surfaces of opposed tubular pistons 171
and 172.
The piston 171 is slidably mounted on a reduced portion 174 of the
front end section 175 of the control rod 33 and is slidable in the
enlarged left end portion 176 of the bore 177 of the valve spool
39. Inward movement of the piston 171 on the control rod is limited
by the engagement of its inner annular end surface with the annular
left end surface of the middle section 178 of the control rod. The
treaded end portion 181 of the end section 175 is threaded in a
suitable threaded bore in the left end of the middle section 180.
Outward movement of the piston 171 or the control rod is limited by
the engagement of its outer annular end surface with the annular
shoulder 183 of the end section 175 of the control rod. Inward
movement of the piston 171 relative to the control rod and the
valve spool is limited by the engagement of its inner annular end
surface with the annulaer end surface of the central section 178 of
the control rod and the internal annular stop shoulder 185 of the
valve spool defining the inner end of the enlarged portion 176 of
its central bore 177. Suitable O-rings 185 and 186 disposed in
annular recesses of the piston 171 seal between the control rod and
the valve spool, respectively.
When fluid under pressure from the pressure passage P is
transmitted to the annular chamber 190 between the control rod
shoulder 183 and the outer end of the piston 171 by means of a
passage 193 of the housing 25 which opens to the recess or groove
111 of the housing, a passage 194 which communicates with the
passage 193, an annular groove or recess 195 of the housing 25, an
external annular recess 196 of the valve body 40 aligned with the
annular recess 195, a port 197 of the valve body, an internal
annular recess 198 of the valve body and a port 199 of the valve
spool which opens to the recess 198 and the chamber 190. An O-ring
201 seals between the piston and the valve spool outwardly of the
port 199.
A plurality of ports 203 of the valve spool open to the fluid
return passage R1 inwardly of the shoulder 185 of the valve spool
so that the outer annular end surface of the piston 171 is exposed
to the high pressure from the pressure passage P while its inner
end surface is exposed to the low pressure in the fluid return
passage R1. As a result, the force exerted on the piston due to
this pressure differential, and in turn exerted on the valve spool
due to the engagement of the inner end surface of the tubular
piston with the shoulder 185 of the valve spool causes the valve
spool to move to the right with the control rod when the control
rod is moved to the right if the valve spool is held against
movement in the valve body with a force greater than the force
exerted thereon by the piston.
The other tubular piston 172 similarly is mounted on the reduced
end portion 210 of the right hand end section 211 of the control
rod, secured to the right hand end of the middle section 178 by an
inner end portion threaded in a suitable bore of the middle
section. The piston is provided with O-rings 214 and 215 which seal
between the piston and the control rod and the valve spool,
respectively. Inward movement of the piston 172 relative to the
spool valve is limited by the engagement of its annular inner end
surface with the internal annular shoulder 216 of the valve spool
defining the inner end of the right end enlarged portion 218 of the
central bore 177 of the valve spool. Pressure fluid is transmitted
to the annular chamber 220 between the outer end of the piston 172
and the annular shoulder 222 defining the inner end of the reduced
portion 210 of the control rod right hand end section 211 through
the housing passage 193, the passage 194, an internal annular
recess 224 of the housing to which opens the right end of the
passage 194, an external annular recess 225 of the valve body which
is aligned with the recess 224, a port 227 of the valve body which
opens to the groove 225, an external recess 228 and ports 229 of
the valve spool which open to the recess 228, an external annular
recess 231 of the control rod end portion 211 to which the port 229
opens, ports 233 which open to the recess 231, and a passage 234 to
which the ports 233 also open. The outer end of the passage 234 is
closed by suitable plug 235. The annular inner end surface of the
piston is exposed to the pressure in the fluid return passage R2
through the ports 236 of the valve spool which open to the flow
return passage R2 and the internal bore 177 of the valve spool
inwardly of the valve spool shoulder 216.
It will now be apparent that if the control rod is moved from its
intermediate position, FIG. 1, to the left, the force of the
pressure of the hydraulic fluid exerted on the outer annular end
surface of the piston 171 will cause the valve spool to move with
the control rod to the left due to the engagement of the annular
inner end surface of the piston 172 with the shoulder 216 of the
valve spool if the force resisting the movement of the valve spool
to the right in the valve body is less than a predetermined valve
which is less than the force exerted by the hydraulic fluid on the
piston 172.
If the valve spool is seized in the valve body, as due to galling
of the lands of the valve spool or presence of extraneous particles
between the valve spool and the valve body so that the normal
operating longitudinally acting force exerted thereon by either the
piston 171 or 172 cannot move it to the left or to the right as the
control rod is moved to the left or to the right, the control rod
will move longitudinally relative to the valve spool. In the case
of the movement of the control rod to the left relative to the
valve spool from the position illustrated in FIG. 1 to the position
illustrated in FIG. 3, the force exerted by the pressure fluid on
the tubular piston 171 will initially resist such movement.
Similarly, if the valve spool due to some malfunction is seized in
the valve body and cannot be moved to the right therein by the
normal operating force, the control rod will be moved to the right
from the position illustrated in FIG. 1 to the position illustrated
in FIG. 2, relative to the valve spool against the force being
exerted by the fluid pressure on the outer end of the other piston
172.
When the control rod is moved to the right, as illustrated in FIG.
2, relative to the valve spool, fluid under pressure from the
external annular recess 231 of the control rod is introduced to the
left end of the cylindrical bore 240 of the valve body 150 of the
deactivating valve assembly DVA to cause a piston 241 slidable in
the bore 240 to move from its non-actuated position, illustrated in
FIG. 1, to its actuated position, illustrated in FIGS. 2 and 3,
through a passage or conduit means which includes an external
conduit 244, one end of which is connected to the housing 25, as at
245 and opens at the inner end of the bore 246 of the housing in
which is disposed the valve body 150 and whose other end is
connected to the housing 25 and opens to an internal annular groove
248 of the housing, an external annular groove 249 of the valve
body 40, a passage 250 of the valve body which opens to the groove
249, a port 251 which opens to the passage, an external annular
recess 254 of the valve spool to which the port 251 opens, and
ports 255 which open directly to the recesses 254 and 231 when the
control rod is in the position illustrated in FIG. 2. The ports 255
are closed by the sealing surface 256 of the control rod when the
control rod is in the positions relative to the valve spool
illustrated in FIGS. 1 and 3.
When fluid pressure is transmitted to the left end of the bore 240
of the deactivating valve assembly DVA, the piston 241 is moved to
the right to its activated position against the resistance of a
spring 260, one of whose ends bears against the annular surface of
an external flange 261 of the piston and whose other end bears
against an annular stop shoulder 264 of a cap 266 whose enlarged
end portion 267 is threaded in the enlarged portion 268 of the bore
of the valve body 150. The piston flange 261 and an extension 269
of the piston are disposed in a cavity or chamber 271 of the cap
265. The chamber 271 is in communication with the fluid return
passage R2 by means of a slot 274 which opens at its outer end to
the chamber and at its inner end to a port 275 of the housing which
in turn opens to the housing recess 56.
It will thus be apparent that as the piston is moved to the right
from the position illustrated in FIG. 1 to the position illustrated
in FIGS. 2 and 3, any hydraulic fluid present in the chamber and
displaced by the movement of the piston may flow outwardly to the
fluid return passage R2 and thus to the fluid return or withdrawal
line 54 of the hydraulic system of the aircraft.
When the control rod is moved to the left relative to the spool
valve 39, FIG. 3, the external recess 231 of the control rod is
placed in communication with the housing groove 248 through ports
283, which are closed by the seal surface 284 of the control rod
when the control rod is in its normal operative position relative
to the valve spool illustrated in FIG 1, the external annular
recess 285 of the valve spool to which the ports 283 open, a port
286 which opens to the recess 285, and the recess 249 of the valve
body 40.
It will thus be apparent that if the control rod is moved either to
the left or to the right from its normal operating position
illustrated in FIG. 1, the pressure of the hydraulic fluid from the
pressure inlet conduit 72 of the aircraft hydraulic system is
transmitted to the left end of the bore 240 of the valve body 150
and moves the piston 241 from its non-actuated position illustrated
in FIG. 1 to its actuated position illustrated in FIGS. 2 and
3.
The piston 241 has an intermediate annular recess 291 between its
external seal surfaces 293 and 294 which sealingly engage the
internal surface of the valve body 150 defining its bore 240. The
seal surface 293 is always disposed to the left of ports 296 of the
valve body which open to the external recess 148 and the seal
surface 294 closes ports 297 of the valve body 150 when the piston
is in its normal non-actuated position illustrated in FIG. 1.
It will be apparent that when the piston is moved to the right to
its actuated position illustrated in FIGS. 2 and 3, fluid
communication is established between opposite ends of the cylinder
14 since the ports 296 and 297 are placed in communication through
the cylindrical passage provided by the external recess 291 of the
piston and the internal surface of the valve body defining its bore
240.
The extension 269 of the piston rod extends slidably through a
longitudinal passage 301 of the cap 265 of the deactivating valve
assembly DVA. A bolt 302 rigidly secures the housing of a normally
open switch 303 in the outer end of the passage 301. The actuator
button 304 of the switch is engageable by the outer end surface 305
of the piston extension when the piston moves to the right to the
position illustrated in FIGS. 2 and 3 to cause closure of the
switch. The switch by means of conductors 306, 307 and 308 connects
a signal lamp 309, which may be located on the control panel of the
aircraft, in series with a source of current, such as the battery
310, to give a visual signal or indication to the pilot of the
aircraft that the particular control valve assembly CVA is
inoperative, as will be explained in greater detail below.
The valve body 150 is also provided with a restricted orifice 312
which opens to an external annular recess or groove 314 of the
valve body 150 which is in communication with the annular groove 64
of the housing. The restricted orifice 312 allows the hydraulic
fluid displaced from the left hand end of the bore 240 of the valve
body 150 as the piston 241 moves from its actuated position,
illustrated in FIGS. 2 and 3, to its non-actuated position,
illustrated in FIG. 1, to flow to the fluid return passage R1.
A dome shaped cover 311 is press fitted on the reduced portion 311a
of the cap 265 and protects the outer end of the cap and the
switch. The conductors 306 and 308 are of course led out of the
cover through a suitable opening of the cover 311.
Hydraulic fluid which may leak into the chamber 26 is returned to
the pressure return fluid return conduit 54 by any suitable means
such as a conduit 317 connected to the housing 25 and the return
conduit 54. For the same purpose, the chamber 319 of the housing
defined by a cap 320 threaded in the outer end of the housing bore
in which the valve body 40 is disposed and is in communication with
the pressure return duct 54 through a duct 322 connected to the
housing which opens to the chamber 319 inwardly of the closure
320.
Suitable seal means, not all of which are shown in the somewhat
schematic drawings, are provided between the various operative
elements of the hydraulic control device 10 at required locations.
For example, O-rings may be disposed in suitable external recesses
of the three valve bodies 39, 78 and 150 for sealing between the
valve bodies and the housing at opposite sides of the external
recesses of the valve bodies. The lands 161 and 166 and the
opposite end surfaces 330 and 331 of the valve body 39 provide a
metal to metal seal with the internal surfaces of the valve spool
40 which they engage.
The sealing surfaces of the pistons 75 and 241 also provide a metal
to metal seal with the valve bodies 78 and 150, respectively.
Assuming now that the hydraulic pressure system of the aircraft is
continuously supplying an incompressible hydraulic fluid under a
predetermined pressure to the hydraulic fluid inlet or pressure
line or conduit 72 and that the hydraulic fluid return conduit 54a
is connected to the return inlet of such hydraulic pressure system,
the bypass valve assembly BV piston 75 is held in its actuated
position illustrated in FIG. 1 by the force exerted by the pressure
of the hydraulic fluid on the area on the left hand end surface of
the piston 75 against the resistance of the spring 76. The
hydraulic fluid in the recess 101 of the piston 75 does not tend to
move the piston in either direction since it exerts equal or
balanced oppositely acting forces on the facing surfaces of equal
area defining opposite ends of the recess 101. In this actuated
position the piston 75 of the bypass valve assembly BV provides
communication between the inlet conduit 72 and the pressure passage
P. The pressure of the hydraulic fluid is communicated through the
various passages, ports and annular recesses of the elements of the
control valve assembly CVA as described above to the chamber 190 in
which the tubular piston 171 is movable so that the pressure of the
hydraulic fluid exerted on the annular piston 171 will tend to
cause the annular piston 171 to move the valve spool 39 to the
right with the control rod 33 as the control rod 33 is moved to the
right and also to the chamber 220 in which the tubular piston 172
is movable so that the pressure of the hydraulic fluid exerted on
the annular piston 172 will tend to cause the valve spool 39 to
move to the left with the control rod 33 when the control rod 33 is
moved to the left.
Assuming further that the control valve assembly CVA is now in
proper operational condition and in the position illustrated in
FIG. 1, the pressure of the hydraulic fluid is now not communicated
to the left hand end of the bore 240 of the valve body 150 of the
deactivating valve assembly DVA since the ports 255 and 286 of the
valve spool are now closed. The various passages of the chambers
are of course filled with the hydraulic fluid. Hydraulic fluid is
now present in the cylinder 14 on both sides of the piston 15 of
the motor device 11 and hydraulic fluid cannot flow either into or
out of the opposite ends of the cylinder since the lands 161 and
166 of the valve spool now close the ports 160 and 165, and thus
the control fluid passages C1 and C2. As a result, the piston is
now held against movement in either direction in the cylinder 14,
and the controlled member 12 is held against movement by the
piston, since the hydraulic fluid is of course incompressible. Each
of the other motor devices 11 each of the other hydraulic control
devices 10, 10a - 10n which control the operation of the other
motor devices 11, 11a - 11n for moving the controlled member 12
have control shafts which are linked to the control shaft 28 of the
control device 10 and to one another or a single common control
shaft 28 operates all control devices 10, 10a - 10a so that the
control rods 33 of the control valve assemblies will be operated
simultaneously by the autopilot or by the pilot himself utilizing
the usual autopilot override linkage.
If it is determined either by the autopilot or the pilot that the
controlled member 12 should be pivoted in a clockwise manner about
the axis of the shaft 19, as the control shaft 28 is rotated in a
counter-clockwise manner, the control rod is moved to the right and
the force of the pressure fluid exerted on the outer end of the
annular piston 171 causes the valve spool to move to the right with
the control rod, as to the broken line position thereof indicated
in broken lines in FIG. 2, to place the pressure passage P in
communication with the control passage C2 through the ports 165
which now open to the recess 70 of the valve spool, hydraulic fluid
under pressure will now flow from the inlet conduit 72 to the right
end of the cylinder 14 through the conduit 155.
The pressure of the hydraulic fluid from the pressure inlet conduit
communicated to the control fluid passage C2 and thus to the ports
297 of the valve body 150 does not tend to cause movement of the
piston 241 in either direction since these ports are now open only
to the circumferential seal surface 294 of the piston.
Simultaneously, such longitudinal movement of the valve spool to
the right places the return fluid passage R1 in communication with
the control passage C1 as the recess 53 of the valve spool moves
into alignment with the ports 160. As a result the piston will be
moved to the left as hydraulic fluid flows into the right end of
the cylinder 14 through the conduit 155 and flows out of the left
end of the cylinder through the conduit 151. As the control member
pivots in a clockwise manner about the axis of the shaft 19 and
approaches the desired position, the control shaft 28 is rotated in
a clockwise direction and the control rod 33 and the valve spool 39
move back to the left to the intermediate position illustrated in
FIG. 1, the force of the fluid pressure in the chamber 220 causing
the tubular piston 172 to move the valve spool with the control
rod. Once the valve spool is again in the intermediate position,
hydraulic fluid can neither enter into nor exit from either end of
the cylinder 14 and therefore the control member 12 will be held
locked in the new position.
Conversely, if it is desired that the control member 12 be moved in
a counter-clockwise manner about the axis of its shaft 19, the
control shaft 28 will be rotated in a clockwise direction, as
illustrated in FIG. 3, and the control rod 33 and the valve spool
39 will move to the left, the valve spool assuming a position such
as that indicated by the broken lines in FIG. 3. As a result, the
recess 52 moves into communication with the ports 165 so that the
fluid from the right end of the cylinder 14 may flow through the
fluid return passage R1 and the various passages described above to
the exhaust conduit 54a and simultaneously the recess 70 of the
valve spool moves into the communication or alignment with the
ports 160 so that fluid under pressure from the pressure passage P
will flow into the left hand end of the cylinder 14. As a result,
the piston will be moved to the right in the cylinder and the
control member 12 will rotate in a counter-clockwise direction
about the axis of its shaft 19. The high pressure hydraulic fluid
which is now present in the recess 291 of the piston 241 will not
tend to move the piston 241 in either direction since its force is
exerted on equal opposite facing areas of the piston defining the
opposite ends of its annular recess 291. As the control member
reaches its desired position, the control shaft 28 is again moved
to position the control rod 27 and the valve spool 39 in the
position illustrated in FIG. 1 and the controlled member 12 will
then be locked in such position by the hydraulic fluid in the
opposite ends of the cylinder 14.
Should the valve spool 39 of the control valve assembly CVA, due to
some malfunction as for example, the presence of a particles of
foreign matter between the engaging surfaces of the valve spool 39
and the valve body 40 be held against longitudinal movement in the
valve body with a force greater than that exerted by the fluid
pressure on the outer ends of the tubular piston 171 and 172, when
the control shaft 28 is rotated in one direction or the other, the
control rod will move relative to the valve spool. If, as
illustrated in FIG. 2, the control shaft is rotated in a
counter-clockwise direction and the valve spool cannot be moved by
the force of the hydraulic fluid pressure exerted on its outer
annular end surface, the control rod will move to the right
relative to the valve spool, the recess 231 of the control rod will
move into alignment with the ports 255 of the valve spool and the
pressure hydraulic fluid will be communicated to the left end of
the bore 240 of the deactivating valve assembly DVA, as explained
above, and its piston 241 will be moved to its actuated position
illustrated in FIG. 2. As the piston 241 moves to its actuated
position against the force exerted by the spring 260, its extension
269 will engage the push button 304 of the switch 303 and will
cause energization of the signal lamp 309 which will then indicate
to the pilot that the control valve assembly 10 is inoperative and
that, as will be explained below, the motor device 11 which it
controls has also been rendered inoperative.
As the piston 241 moves to its actuated position, its outer recess
291 moves into communication with the ports 297. As a result, a
bypass passage between opposite ends of the cylinder 14 is
established through the conduit 151, the aligned recesses 147 and
148 of the valve body 150 and the housing 250, respectively, the
ports 296, the cylindrical passage defined by the external recess
291 of the piston 241 and the bore 240 of the piston, the ports
297, the aligned recesses 154 and 156 of the housing and the valve
body 150, respectively, and the conduit 155. As a result, the
piston of the motor device 11 will now be free to move in the
cylinder in either longitudinal direction as the control member 12
is pivoted about the axis of the shaft 19 by the other motor
devices.
Since the orifice 312 is of very relatively small dimensions, it
will allow a hydraulic fluid under pressure to continuously flow
therethrough at a low rate to the fluid return passage R1 but
provides enough of a restriction that a pressure in the bore 240
will remain high enough value that the piston will be held in its
actuated position thereby against the resistance of the spring 260
as long as the recess 231 is in communication with the ports
255.
Should the force with which the valve spool 39 is held against
movement to the right in its valve body 40 decrease below that of
the force of the fluid pressure on the piston 171 the force of the
fluid under pressure exerted on the tubular piston 171 will of
course move it back to the right in the valve body. In that case,
as the control rod recess 231 moves out of communication with the
valve spool ports 255, the left end of the bore 240 will be placed
out of communication with the pressure hydraulic inlet conduit 72
and the force exerted by the spring 260 will be effective to move
the piston back to its non-actuated position illustrated in FIG. 1,
the hydraulic fluid trapped to the left of the piston in the bore
240 flowing outwardly through the restricted orifice passage 312
back to the fluid return passage R1.
Conversely, as illustrated in FIG. 3, if for one reason or another
the force resisting the movement of the valve spool to the left in
the valve body 40 exceeds the force exerted by the tubular piston
172 on the valve spool, as the control shaft 28 is rotated in a
clockwise manner and moves the control rod 33 to the left, the
valve spool will remain stationary in the valve body and the
control rod recess 231 will move into communication with the ports
283, the pressure of the hydraulic fluid from the inlet conduit 72
is communicated to the left end of the bore 240 of the valve body
150. As explained above, the piston 241 is moved into its actuated
position, the piston 15 of the motor device 11 is freed to move in
either direction in the cylinder 14, and operation of the
controlled member 12 by the other motor devices 11a-11n . . . n
will not be hindered or impeded by the motor device 11.
The annular recesses 231, 254 and 285 of the valve spool 39 are of
such lengths that should the valve spool be seized or held against
movement relative to the valve body 40 when in either of its
extreme right or left positions, indicated in broken lines in FIGS.
2 and 3 of the drawings, if the control rod is moved longitudinally
relative to the valve spool while it is in such extreme right or
left positions relative to the valve body, hydraulic fluid under
pressure will be communicated to the left end of the bore 240 in
the same manner as when the control valve spool is in its
intermediate position and the piston 241 of the deactivating valve
assembly will be moved to its actuated position.
If the aircraft hydraulic system is rendered inoperative so that
fluid under pressure is not transmitted through the inlet conduit
72, the force of the spring 76 will be effective to move the piston
75 of the bypass of valve assembly BV to its inoperative position,
illustrated in broken lines in FIG. 1. In this inoperative
position, the seal surface 335 of the piston closes the ports 116
and opens the ports 126 as the piston recess 125 moves into
communication therewith. As a result, the pressure passage P is
placed out of communication with the pressure inlet conduit 72 and
the control passages C1 and C2 are placed in communication with one
another through the cylindrical passage provided by the annular
external recess 125 of the piston 75 and the internal bore 106 of
the valve body 78 and a bypass passage path for hydraulic fluid is
provided between opposite ends of the cylinder 14. The control
member 12 will be free to move since the piston 16 of the motor
device can now move in either direction since the hydraulic fluid
being free to circulate between opposite ends of the cylinder as
the piston is moved therein.
It will now be seen that a new and improved hydraulic control
device 10 has been illustrated and described which is used to
control the operation of a hydraulic reversible motor device, such
as the motor device 11, which operates in one direction when
hydraulic fluid under pressure is transmitted to a first fluid
passage thereof and allowed to exhaust from a second fluid passage
thereof, operates in an opposite direction when the fluid under
pressure is transmitted to its second passage and allowed to
exhaust from its first passage, and is held against operation when
flow of fluids to or from both passages is prevented.
It will further be seen that the control device 10 includes a
control valve assembly CVA having a valve member or spool 39
movable longitudinally in a body means, such as that formed by the
housing 25 and the valve body 40, the valve member and the body
means cooperating selectively to permit flow of hydraulic fluid
under pressure to one of the first and second passages and
permitting the exhaust from hydraulic fluid from the other of the
first and second passages and permitting the exhaust from hydraulic
fluid from the other of the first and second passages when the
valve member is in opposite extreme longitudinal positions, and
preventing the flow of fluids through the passages in either
direction when the valve member is in intermediate position
relative to the body means.
It will further be seen that the valve member is movable in the
body means by a control means, such as the control rod 33 and the
tubular pistons 171 and 172 which are operatively associated with
the valve member, the tubular piston exerting oppositely directed
forces on the valve member whose values are predetermined by the
pressure of the hydraulic fluid and the areas of the surfaces of
the tubular pistons exposed to the fluid pressure, on the valve
member tending to cause the valve member to move with the control
rod.
It will further be seen that the control device 10 includes a
deactivating valve assembly DVA, actuated upon the occurence of
relative movement between the control rod and the valve member,
which occurs when the longitudinal movement of the valve member is
resisted by a force greater than the forces exerted thereon by
either of the tubular pistons, for providing a bypass fluid passage
or path for hydraulic fluid between the two passages of the motor
device.
It will further be seen that a new and improved apparatus for
operating a control member, such as an aileron 12, spoiler or the
like, of an aircraft has been illustrated and described which has a
plurality of simultaneously operable motor devices, such as the
motor devices 11, 11a . . . 11n whose operation is individually
controlled by separate control devices 10, 10a . . . 10n,
respectively, and that each control device has means for
de-activating the motor device 11 controlled thereby in the event
of malfunction of the control device so that the operation of the
control member 12 by the other motor devices, whose control devices
10 are still functioning properly, will not be impeded or hindered
by the motor devie whose control device is inoperable or has
malfunctioned.
The foregoing description of the invention is explanatory only, and
changes in the details of the construction illustrated may be made
by those skilled in the art, within the scope of the appended
claims, without departing from the spirit of the invention.
* * * * *