US3683749A

US3683749A - Hydraulic control means

Info

Publication number: US3683749A
Application number: US43325A
Authority: US
Inventors: Fred R Bayles
Original assignee: Ltv Electrosystems Inc
Current assignee: Ltv Electrosystems Inc
Priority date: 1970-06-04
Filing date: 1970-06-04
Publication date: 1972-08-15
Anticipated expiration: 1989-08-15
Also published as: GB1342675A; FR2094052B1; FR2094052A1

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.

Description

United States Patent Bayles [54] HYDRAULIC CONTROL MEANS [72] Inventor: Fred R. Bayles, Dallas, Tex.

[73] Assignee: LTV Eleetrosystems, Inc., Dallas Tex.

22 Filed: June4, 1970 211 Appl.No.: 43,325

Primary Examiner-Edgar W. Geoghegan Att0rney-Walter J. Jagrnin and James D. Willbom I14 I26 1317 V [4-51 Aug. 15, 1972 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.

5 Claims, 4 Drawing Figures PATENTEDAUB 15 m2 SHEET 1 [IF 3 .v ,..,c R N L WT EV! r Rm EN; mmm mm NON Mom mom PATENTEDAus 15 1912 saw a or 5 INVE/VTUR FRED R. BAYLES ATTORNEY PATENTEDAUG 15 m2 3.683; 749 sum 3 or 5 Fig.3

IIVil/E/VTOR FRED R. BAYLES ATTORNEY HYDRAULIC CONTROL MEANS 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 oppositeends 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 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 having a chamber 26 which is closed at one end by a closure 17. A control shaft 28 suitably joumaled 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 counterclockwise 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 340 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 com munication 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 engag ing with the intermediate seal surface 164 of the valve body 40 to close the ports 160. v

The valve body 40 has similar ports 165 which open to the annularrecess 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 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 I83 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 bodyv 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 21 1 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 F IG. 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 recess23l of the control rod is introduced to the left end of the cylindrical bore 240 of the valve body 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 intemal 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. I 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 30] 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. I, 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 31 l.

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 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 1 1 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, 10 a ln 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 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 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 Cl 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 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 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 counterclockwise 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 2% 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 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 lla-lln n will not be hindered or impeded by the motor device 1 l.

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 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 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 pennit 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 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 l2, 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 lln whose operation is individually controlled by

separate control devices

10, 10a l0n, 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.

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 sum from said inlet means to one of said flow passages of a hydraulic motor device permitting flow of fluid from the mot r device from its other flow pas ige means to sai outlet means, and preventing ow 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 pemiit 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.

" UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,683,749 Date d ugust 15, 1972 fiven f Fred R Rayl e It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Abstract, line 8 [Pg. 1 ln 9] after "such" insert -as- Column 1, line 6 [Pg. 1, 1n. 24] "05" should be -is-.

Column 3, line 42 [Pg. 5, ln. 7] "17" should be -27-.

Column 7, line 6 [Pg. 11, ln. 14] "or" should be -on-.

Column 8, line 57 [Pg. 14, ln. 20] "position" should be positions- Column 11, line 49 [Pg. 19, ln. 28] "l0al0a" should be -l0a-lOn- Column 12, line 66 [Pg. 22, ln. 5] "piston" should be pistons-. Column 14, line 28 [Pg. 24, 1n. 25] after "bypass" delete "of".

wiww UNITED STATES PATENT OFFICE (/69) CERTIFICATE OE CORRECTION Patent No. 3,683, 749 Dated August 15, 1972 Inventor-(s) Fred R. bayles 1 I It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 4, line 25 [Pg. 6, In. 18] "rt" should be "56";

line 53 [Pg. .7, 1n. "34a" should be 83-. Column 6 line 21 [Pg. 10, ln. 1] "164" should be- -l66-;'"=.

line [Pg. 10, ln."5] "FIGURE 4" should be -FIGURE 2 line [Pg. 10, ln. 9] "54'7 Should be 54a-; line 48 [Pg. 10, ln. 2s] "54" should be -54a-. Column 7, line l7 [Pg. 11, ln. 22] after "O-ring" delete "185 and". Column 9, line 14 [Pg. 15, ln. 9 "zoo" should be --2os--. Column 10, line [Pg. l7,'ln. 21] "54" should be --54a--; line 36 [Pg. 17,. ln. 23] "54" should be 54a--; line 41 [Pg. 17, 111. 2d] "54" should be -54a'-.

Column 12, line 53 [Pg. 21, ln. 27] "27" should be --33. Column 13, line 26 [Pg. 22, ln. 28] "250" should be --25--. Column 14, line 43 [Pg. 25, ln. 5] "16" should be --15--.

Signed and sealed this 23rd day of January 1973..

:SEAL) lttest:

EDWARD M.PLETCH'ER,JR. ROBERT GOTTSCHALK Ittesting Officer Commissioner of Patents

Claims

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.

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.