US3153989A

US3153989A - Actuator

Info

Publication number: US3153989A
Application number: US104435A
Authority: US
Inventors: Bruce D Roberts
Original assignee: Central States Tooling Service Inc
Current assignee: Central States Tooling Service Inc
Priority date: 1961-04-20
Filing date: 1961-04-20
Publication date: 1964-10-27
Anticipated expiration: 1981-10-27

Description

Oct. 27, 1964 B. D. ROBERTS 3,153,989

, ACTUATOR Filed April 20, 1961 3 Sheets-Sheet 1 FIG -1 20,

o o Z6 a 22 22 4FlG-2 sz 54 56 25 H6 I50 I s z4o 24! 19s 66 6-71 59 L INVENTOR. BRUCE D. RQBERTS 0 I35 y MW W ATTORNEYS Oct. 27, 1964 B. D. ROBERTS 3,153,989

ACTUATOR Filed April 20, 1961 3 Sheets-Sheet 5 9 FIG -IO FIG 8 n 1 l/\ 1 f2? zlo o #221 .qll w 250- -20! 236 246 24; J 349 A Q. 200 I2 l2 I I a 240 In: I I I \ZOI O O 22! O O 9 FIG 3/0 30 FIG -II &

INVENTOR.

BRUCE D. ROBERTS ATTORNEYS ,BY 220 256 2 wwwa United States Patent 3,153,989 ACTUATOR Bruce D. Roberts, Dayton, Ohio, assignor to Central States Tooling Service, Inc., Dayton, Ohio, a corporation of Ohio Filed Apr. 20, 1961, Ser. No. 104,435 Claims. (Cl. 92-136) This invention relates to actuators and more particularly to a shaft positioning, remote receiver or slave unit of a hydraulic control system.

The apparatus of this invention is particularly adapted for use as a direct throttle actuator for an internal combustion engine, and has particular utility for the operation of a fuel metering governor and/or a fuel cut-off valve. An example of one such application of this invention is the actuation of the fuel controller of a jet engine in a test cell. Such installations demand that the actuator be reliable, that it be capable of repeated movement to the same position, as required, that it be easy to assemble or attach to the engine and to remove, that it hold a given position and not be aifeoted by vibration, and that it be adapted for rapid and thorough bleeding to remove all air which may be entrapped therein.

The above requirements and others are fulfilled by the actuator of this invention which includes a self-contained piston motor and an output shaft mounted in a housing which is adapted for quick connection on and disconnection from a fuel control device, such as the main fuel controller on a jet engine. Provision is included for the thorough purging of all air which might be entnapped within the cylinder motor so that when the fluid system is pressurized the piston is eliectively locked up for synchronous movement with a remote sending unit. The body is preferably divided into a base and an outer housing which are positionable with respect to each other so that the cylinder motor can be positioned most advantageously for its operation and for the purging of entrapped air.

Provision is also preferably included for the internal driving of otentiometers, remote position transmitters, and the like, so that an operator may readily ascertain and follow the movement of the throttle control. Also, the unit preferably includes a pair of cylinder motors with a pair of separate controlled concentric output shafts to provide for the control of two input shafts, such as for the control of fuel flow rate and fuel cut-off.

It is therefore a principal object of this invention to provide a remote actuator unit characterized by simplicity, ruggedness, versatility, and ease of operation.

A further important object of this invention is to provide a remote actuator unit as outlined above including provision for the thorough purging of any air which might be entrapped within hydraulic cylinder motors.

Another object of this invention is to provide an actuator unit as outlined above characterized by its ease of installation and removal from an engine.

A still further object of this invention is to provide an actuator unit as outlined above which is readily adapted for use in existing fuel control systems without modification of the existing sending units or the compensator units.

Another object of this invention is to provide an actuator unit which includes automatic preloading of the engaged gears for the removal of the backlash.

A still further object of this invention is the provision of an actuator unit as outlined above including provision for remote position indicators.

Another object of this invention is to provide an actuator unit as outlined above including a pair of separate and isolated hydraulic fluid motors which are com- 3,153,939 Patented Got. 27, 1954 ice ' shafts and other attachments which create backlash.

A further object is to provide an actuator which may be attached and locked without safety wiring the attaching bolts.

Other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.

In the drawings FIG. 1 is a somewhat diagrammatic elevational view of a fuel control system of a jet engine including an actuator unit constructed according to this invention;

FIG. 2 is -a longitudinal section through the actuator unit of FIG. 1 taken generally along the line 22 of FIG. 3;

FIG. 3 is an elevational view of the actuator unit with the cover plate removed and with one of the hydraulic motors being in section, this section taken generally along the line 3-3 of FIG. 4;

FIG. 4 is a fragmentary section through a portion of the actuator showing the details of the cylinder motors taken generally along the line 4-4 of FIG. 3;

FIG. 5 is a fragmentary elevational detail of a portion of the cover plate and one of the retaining bolts;

FIG. 6 is an enlarged section through a drive gear for a remote position transmitter;

FIG. 7 is a perspective view of the backlash preload spring of the gear of FIG. 6;

FIG. 8 is an elevational view looking at the inside surface of the left-hand cylinder block, with the part being oriented as shown in FIG. 4;

FIG. 9 is a section through the left-hand cylinder block taken generally along the line 99 of FIG. 8;

FIG. 10 is an elevational view looking into the interior of the right-hand cylinder block with the part being oriented as shown in FIG. 4;

FIG. 11 is a section through the right-hand cylinder block showing one of the bleed valves "and the bleed passageways taken generally along the line 11-11 of FIG. 10; and

FIG. 12 is a further section through the right-hand cylinder block showing the bleed valves taken generally along the line 12.12 of FIG. 10.

Referring to the drawings, which illustrate a preferred embodiment of the invention, a jet engine 20 is somewhat diagrammatically, as it would appear on a stand within a jet engine test cell. The jet engine 20 includes a fuel controller indicated generally at 22 fixed at the side of the engine 20. A throttle v alve servo or throttle position actuator 25 constructed according to this invention is shown as being mounted on the controller 22.

The actuator 25 provides the means by which the operation of the jet engine 20 may be remotely controlled by the test cell operating personnel at a remote position within a control room. Thus, the operator may have before him a fuel control handle 26 and a throttle control handle 27 by means of which he controls the operation of the engine 20. The fuel handle 26 is connected to operate the actuator 25 by means of a suitable doubleacting hydraulic fluid displacing device commonly known as a transmitting or sending unit 38. The unit 30 may consist of any suitable type of hydraulic transmitting unit, and the part number 13864 of Adel Precision Products Corporation, Burbank, California is given as an example of one such unit suitable for this purpose, and forms no part of the present invention. Similarly, the

throttle handle 27 operates another sending unit 31 which may be identical in construction to the sending unit 51 The unit 39 is connected to operate the actuator 25 through a pressurized closed hydraulic circuit which includes a pair of

hydraulic lines

35 and 36, while the transmitter unit 31 operates the actuator by means of a separate hydraulic circuit which includes a similar pair of hydraulic leads or

lines

37 and 38. Since each of the units 39 and 31 are part of separate hydraulic systems, they are preferably separately purged and pressurized by means of suitable compensating units indicated at 41) inserted within the respective hydraulic lines 35-36 and 37-38. The units 41) form no part of the present invention, as such, and prefrably include a pump handle 41 and an accumulator portion 42 by means of which the hydraulic system involved may be purged of air and pressurized by pumping of hydraulic fluid from a tank or can 45. An example of a suitable compensating unit for this purpose is RN. 15915 of Adel Precision Products, above.

The actuator 25 preferably includes provision for recording and remote position indicating. Thus, a remote position indicator 46 and an oscillograph recorder 47 may be operated by suitable electrical sending units lo cated within the actuator, as will be described in greater detail hereinafter.

Referring to FIGS. 2-4 and in particular to FIG. 2, the actuator is shown as including a generally cylindrical hollow central body or housing 511) which supports a cover plate 51 at the outer end thereof and which includes a frame portion or base 52 at the inner end thereof. The cover plate 51 is retm'ned on the housin 50 by screws 53 while the base 52 is retained on the housing 50 by screws 54. The central housing 50 together with the base 52 and cover plate 51 form an assembly which is suitably secured to the controller 22, shown in broken outline fragmentary form in FIG. 2, by a plurality of axially extending retaining bolts 55. The bolts 55 are arranged to extend through the cover plate 51, the interior of the housing 51), and through suitable axial openings 56 formed within the base 52 and are provided with threaded inner ends 58 for engagement with suitable tapped holes in the controller 22. 'O-rings 59 retain the bolts when the actuator is removed.

A particular feature of this invention resides in the ease by which the actuator 25 may be connected to and removed from the engine fuel controller to save time in the removal of one engine 20 from the test stand and its replacement by another engine. This ease in assembly and in removal is facilitated by the arrangement of the mounting bolts 55 including threaded inner ends 58 for the attachment to the controller 22 and a head or cap 60 formed on the outer ends and having a transverse or cross pin 61 extending therethrough. The cover plate 51 includes a spider with four radially extending arms 64 mounted on the inside surface by cap screws 65 and formed with offset portions 66 arranged adjacent the bolts 55. The portions 66 each support a latch or locking pin 68 for reciprocal movement.

The pins 68 are formed with a collar 65 thereon and a small compression spring 71 is interposed between the portion 66 and the collar and serve to bias the pins 68 outwardly through suitable clearance openings formed through the cover plate 51. The extended ends of the pins 68 are proportioned to engage the extended ends of the transverse pins 61 to prevent the rotation of the retaining bolts 55 and thus serve to safety the actuator 25 onto the controller 22.

The pins 68 are readily depressible by a suitable tool such as is indicated at 71 adapted with an opening 72 which may be slipped over the heads 60 in driving engagement with the transverse pins 61 by a slot 73. The tool 71 depresses the pin 68 into an inoperative position when applied to the head 61). The tool 71 is proportioned so as to allow the bottom of the slot 73 to travel over the top of the pin 68 without interference. When the tool is removed, the pin 68 returns outwardly to a projecting position in engagement with the transverse pin 61 (FIGS. 2 and 5) and thus eliminates the necessity for the use of safety wire.

The base 52 of the actuator includes a mounting flange portion 75 adapted for mounting against a suitable flange or cooperating portion formed on the fuel controller with the actuator secured by the bolts 55. The base 52 further includes means for driving the fuel controller input shafts including a pair of concentric output shafts which are rotatably received within a bearing flange 76 formed in the base 52. The concentric shafts includes an outer shaft 80 rotatably mounted on a bearing race 81 and formed with a suitable driving connection such as the tongue 82. An inner shaft 85 has an inner drive end mounted within the shaft 89 on a pair of spaced apart bearings 38 and S9, and includes a driven end supported on a bearing received within a bearing support wall 96 within the center housing 50.

Drive means for the outer shaft 80 includes a main gear 156 secured to a flange 101 on the shaft 80 by bolts 102 and a roll pin 193. The main gear 1110 includes a hub portion 155 rotatably received on a boss 106 formed on the inner shaft 85.

Driving means associated with the inner shaft 85 includes a sector gear 110 (FIGS. 2 and 3) which is keyed on the inner end thereof and retained by a nut 112. The gear 110 has the same pitch diameter as the gear 100.

The actuator includes provision for the sending units for remote position indicating units, and a precision potentiometer is shown as a sending unit for the oscillograph 47 and a position responsive sender 116, commonly known as an autosyn, is shown as the sending unit for the indicater 46. These units are mounted on the wall 96 within the housing 56 adjacent the extended end of the inner shaft 85 as shown in FIG. 3. Thus, the

units

115 and 116 are totally enclosed within the housing 50 by the cover plate 51 and are thus protected from dirt.

Means for driving the units according to the position of the outer shaft 81) includes the main gear 190 which has mounted thereon a smaller drive gear 12%) joined by a pin to the main gear and held by a snap ring 121. The drive gear 120 comprises the means by which the remote position sending units are driven in relation to the position of the shaft 81), which is preferably the shaft which operates the throttle mechanism of the governor, and thus the units provide an indication of throttle position. Each of the sending

units

115 and 116 are driven off of the gear 121), and the drive arrangement for the autosyn unit is shown in FIG. 2 as having an input shaft 124 and an antibacklash gear 125 in driven relation to the driving gear 120.

The driven anti-backlash gear 125 is formed in two parts as indicated in FIG. 6 and includes an outer relatively thin split portion 126 mounted on a main portion 127 by a spring 136. The main portion 127 is adapted for mounting on the shaft 124 and is formed with a pair of diametrically opposed axially aligned openings 133 and 134 through which the

legs

135 and 136 of the backlash preload spring may be inserted The legs of the spring are received within suitable clearance openings 138 provided within the gear portion 126. The spring 1313 is formed with an arc-like connecting portion 141) joining the inner ends of the two legs. The legs and 136 are formed in a slightly non-axial spread apart relation as shown in FIG. 7 wherein the broken lines are parallel to the axis of the gear. When the backlash preloadspring 1511 is assembled within the gear, the

legs

135 and 136 preload the split gear portion 126 thereby providing an unusually compact anti-backlash drive gear for the remote position indicators.

The actuator 25 includes separate shaft drive means through which either or both of the shafts 85 and 30 may be separately positioned. The shaft drive means includes a pair of hydraulically separate double-acting cylinder motors, as are best shown in FIGS. 3 and 4. The cylinder motors are each substantially identical one to the other, and the front motor shown in partial section in FIG. 3 will be described in the greatest detail, it being understood that the description thereof applies equally to the more rearward or inner motor, unless otherwise noted. The front motor includes means for driving the sector gear 113 and inner shaft 85 while the rear motor drives the main gear 1%, the outer shaft 86 and the

units

115 and 116.

The front motor consists of a cylindrical tube 1543 extending through the housing 59 transversely of the axis thereof through suitable openings formed within the housing wall. The cylindrical tube 159 thus forms a hydraulic cylinder which is positioned generally transverse to the concentric output shafts and contains a double-acting hydraulic piston member 155 reciprocably received therein. The piston member 155 is formed with opposite ends providing bearing surfaces 153 and 159 with the inside surface of the cylinder 15% and is further provided with sealing means consisting of V-block rings 16th and 161 received within suitable recesses formed adjacent the opposite ends of the piston member 155. Thus, the portion of the member 155 intermediate the sealing means is isolated from fluid contact, and is formed of slightly reduced crosssectional diameter.

Drive means associated with the piston member 155 includes a rack gear 163 which extends longitudinally from a position adjacent one of the bearing surfaces 158 to a position adjacent the opposite bearing surface 159. The rack gear 163 is preferably formed of hardened steel and is press-fitted into engagement with a cooperating slot formed within the member 155, which may be formed of aluminum.

The cylinder 150 has one side thereof cut away as indicated at 165 to form an opening centrally thereof positioned inwardly toward the interior of the housing 56). This opening 165 provides clearance for the movement of the sector gear 114 therein in engagement with the rack 163. Also, the piston member 155 has a portion thereof cut away adjacent either side of the rack 163 as indicated at 166 and 167 for the purpose of facilitating assembly.

The bearing surfaces 158 and 159 are provided with a running clearance within the cylinder 150 in the order of a few thousandths of an inch. This running clearance provides a small amount of freedom of movement in a direction transverse to the axis of the cylinder. The pressurization of the hydraulic system effects the expansion of the V-block rings 16% and 161. Therefore, when the rings 16% and 161 are pressurized, the piston member 155 tends to be held centrally of the cylinder 15% and urges the engagement of the rack 163 with the teeth of the gear 11d. Thus, this arrangement provides, in effect, for the fluid cushioned engagement of the associated rack and gear with a minimum of backlash or clearance. Pressure relief openings 179 between the V-ring recesses and the outside surface of the heads provide for pressure relief upon the reversal of movement of the member 153 and further provide for the complete relief of pressure within the rings upon disassembly of the actuator.

The hydraulic fluid motor mechanism for driving the main gear 160 is essentially the same as that which has so far been described in connection with the sector gear 110, and the parts thereof including the cylinder 150 and the piston member 155 of each of these motors are, in fact, preferably interchangeable. One difference exists, however in the provision of a spacer 172 having a fluid access opening 173 therethrough and positioned within the cylinder 150 of the front motor to prevent excess travel of the member 155 in relation to the gear 11%. It is, of course, within the scope of this invention to provide a full 360 gear in lieu of the sector gear 110, and relatively longer or shorter rack gears 163. It is further within the scope of this invention to provide any degree of angular rotation of the shafts and according to the requirements of the governor or other controlling device which may be positioned by this actuator.

The opposite open ends of each of the cylinders are enclosed within cylinder blocks and are held in the assembled position by tie bolts. The cylinder blocks provide the means by which fluid pressure may be administered selectively to either side of each of the fluid motors and further provide the means by which each of these motors may be bled and purged of air upon assembly. The block 206) on the left-hand side will be described first and reference may therefore be had to FIGS. 4, 8 and 9 for a detailed showing thereof. The cylinder block 200 is formed with bored openings 201 within which the extended ends of the cylinders 150 are received. An O-ring 262 provides a fluid seal between the block 2% and the outside surface of each of the cylinders 15% The block 2% is tapped from the outside surface inwardly at 205 and 206 to provide for threaded inlet connectors 20S and 209. These tapped

openings

205 and 2% extend into the interiors of the respective cylinders 150 through annular spacer disks 21d and provide the means by which hydraulic fluid may be administered to the left side of each of the motors.

Means for retaining the block 2% in its assembled position over the ends of the cylinders 150 include four elongated bolts 215 which pass through suitable clearance openings formed adjacent the four corners of the block 2%. The bolts 215 have threaded inner ends which are received within tapped openings formed through the wall of the housing 50, as shown in FIGS. 3 and 4.

The right-hand cylinder block 225 is formed with a pair of inwardly facing openings 221 similar in function and purpose to the openings 2111 of the block 2% to receive the extended ends of the cylinders 150 therein. O-rings 222 provide a seal therewith. The block 220 is retained in a manner similar to that described above and includes a retainer cap 225 mounted on the outer surface thereof, the purpose and function of which will be described below. The assembled retainer cap 225 and the block 220 are secured by four longitudinally extending bolts 226 passing through the body and cap and threaded into the housing 54 Means for admitting fluid into the interior of the cylinder 150 at the right-hand end of the piston members includes a pair of tapped openings 228 and 229 (FIG. 4) formed at right angles to the pistons. The

openings

228 and 229 connect with drilled passageways 230 (FIGS. 3 and 10) joining the tapped openings and the interior of the cylinders 15%.

An important feature of this invention resides in the provision of means for purging each of the hydraulic cylinder motors of all entrapped air therein. This is particularly important to the successful operation of an actuator in a jet engine test stand wherein its is desired that the actuator be readily assembled and brought into a state of operation with a minimum of time and delay. It is also essential to proper operation that all air be removed so that the piston members 155 accurately follow and reproduce the position of the

handles

26 and 27 of the sending units.

In general, the bleeding of the hydraulic motor portion of the actuators is accomplished, in part, by externally positioned bleed passageways or tubes, one being provided for each of the hydraulic motors. The bleeding operation is effected by providing for the circulation of hydraulic fluid into one of the inlets at one of the blocks, through the external bleed passageway and out of the inlet at the opposite block. This circulation is effected by the pump of the compensator.

In particular, the bleed system includes means connecting the respective fluid chambers of each of the hydraulic motors at each of the cylinder blocks in the form of a pair of

tubes

240 and 241 which extend between the cylinders through suitable openings provided within the wall of the central housing 50. The

tubes

240 and 241 are shown in section in FIG. 2 between the cylinders 15% and the end connections thereof are shown in FIGS. 812.

Referring to FIGS. 8 and 9, it is seen that an annular groove or recess 245 is formed at the end Wall defining the opening 2521 behind the disk 21d and a diagonal drilled passageway 246 connects the annular groove 245 to an axial passageway 248 which, in turn, is formed with a recessed portion 24s to receive the innermost end of the bleed tube 240. As shown in FIG. 8, similar passageways are provided in the left cylinder block for the other hydraulic motor. Also as shown in FIG. 8, each of the disks 210 include a bleed opening 25513 which, upon assembly, is positioned upwardly in accordance with the operating position of the actuator so that it is at the high point of the associated fluid chamber.

As shown in FIGS. -12, the opposite extended ends of the

bleed tubes

240 and 241 are supported within suitable openings formed within the right cylinder block 220, and are connected to their respective fluid chambers within the cylinders 155 through

bleed needle valves

255 and 256 which are threaded into suitable valve openings formed within the cylinder block 220. There is provided one bleed valve for each of the tubes 24d and 241. The bleed valves are normally closed with their pointed ends 257 threaded against the inside ends 258 of their respective tubes. The cap 225 serves as a retainer for the

valves

255 and 256 and is formed with access openings 260 through which the needle valves may be either opened or closed. A passageway 262 connects each of the valves to a relieved portion 263 formed within the cylinder block 220 at the base of the openings 221 thereby connecting the tubes 244) and 241 to their respective hydraulic chambers for air purging.

In the purging operation, the associated handle 4-1 of one of the compensators 40 is operated to draw hydraulic fluid from the tank 45 and to apply this fluid under pressure to one of the

inlet connectors

208 or 209 through the hydraulic lines. It is preferable that the hydraulic fluid be applied to the inlets at the cylinder block 200 for circulation through their respective hydraulic chambers within the cylinders 159 through the tubes 24% and 241, and through the chambers in the right-hand cylinder block 222. The

bleed valve

255 or 256 associated with the particular motor being purged is opened to provide flow of the hydraulic fluid externally of the hydraulic motors from the fluid chamber in the block 2% to the opposite chamber within the block 22%. The disk 21% is preferably positioned on assembly to place the bleed opening 250 upwardly with respect to the block 206) to provide for the removal of all air which may have been entrapped therein.

In this manner, by observing the condition of the hydraulic fluid being returned to the tank 45 for the absence of all air bubbles, each of the hydraulic motors may be quickly and thoroughly purged of all entrapped air. The associated

bleed valve

255 or 256 is then closed and the handle 41 is further operated to pressurize the system by means of the accumulator portion 42 of the compensator 4h. The system may be pressurized in the order of 650 p.s.i., as an example. The system is now ready for operation by the fluid pressure transmitting units 30 and 31.

The hydraulic cylinders are preferably mounted in the horizontal position for the most advantageous purging of air. However, it may be desirable to mount the cylinders in another position due to the space requirements. Therefore, the actuator includes provision for the mounting of the housing 51) in any one of four 90 positions with respect to the base 52. This is readily accomplished by the removal of the bolts 55 and the removal of the machine screws 54. The housing 50 may then be turned relative to the base 52 into a new quadrature position and the screws 54 re-inserted.

In the operation of the actuator subsequent to purging and pressurizing described above, movement of one of the

handles

26 or 27 effects transverse positioning of one of the piston members 155. This, in turn, is directly translated to the rotation of one of the gears I06 or through the rack I63 carried by the piston member. There is a minimum of backlash in this mechanism due to the effect of the pressurization of the V-block rings 160, 161 which urge the piston member 155 centrally within the cylinder and urge the engagement of the rack and gear.

The transmitter units and 116 are similarly positioned in accordance with the position of the main gear Elli through the anti-backlash gears 125. Thus, the position of the outer shaft fill may be constantly read at the indicator 46 and recorded at the oscillograph 47. The inner shaft 85 may be most conveniently employed as the fuel shut-otf control.

Although the embodiment herein shown and described includes concentric shafts and dual hydraulic motors, it is understood that it is within the scope of this invention to provide a single useful shaft operated by a single hydraulic motor arranged according to this invention. Further, the tie bolts which secure the cylinder blocks may be extended entirely through the housing. Also, the pins 68 may be received within suitably countersunk openings formed in the housing wall rather than being supported by the spider 64.

It is therefore seen that this invention provides a compact receiver or actuator. It is to be understood that the use of this invention is not limited to application to governors on jet engines, as illustrated and described, but may be used with advantage in any installation where exact positioning of one or more shafts, levers or the like is required. Thus, the invention may be used with advantage for the remote control of power settings for diesel engines and the like which may, for instance, be controlled remotely from a flying bridge on a boat.

While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. A throttle valve control servo comprising a housing, a onepiece cylindrical tube supported in and extending through said housing, a double-acting piston member received in said tube and having opposite piston ends in spaced relation to the ends of said tube and forming a fluid seal with the inside wall surface of said tube, the movement of said piston member in said tube being wholly confined to the axial limits of said tube, means in said tube defining an opening centrally thereof and positioned inwardly to said housing, a rack gear formed in said piston member adjacent said opening, an output shaft rotatably mounted in said housing and having a gear thereon in intermeshing relation with said rack gear for rotational movement in said opening upon the transverse movement of said piston member, a separate cylinder head block carried on each end of said tube closing the ends thereof and forming fluid chambers Within said tube adjacent said piston ends, tie bolt means extending through each said cylinder head block and extending into said housing retaining said head blocks in closing relation to the ends of said tube and retaining sadi tube in fixed axial position in relation to said housing, and flud inlet means in each of said blocks connected to said cham ber providing passageways for the application of hydraulic pressure to said chambers to effect transverse positioning movement of said piston member in said tube.

2. A throttle valve control servo comprising a generally cylindrical housing, a one-piew cylindrical tube extending transversely of said housing on an axis radially spaced from the axis of said housing and having a central portion thereof received in said housing with the opposite ends thereof extending outwardly of said housing, a double-acting piston member received in said tube and having opposite piston ends in spaced relation to the ends thereof, means in said ends forming a fluid seal with the in side Wall surface of said tube, means in said tube defining an opening intermediate the ends thereof and opening into said housing, a rack gear formed in said piston member adjacent said opening, an output shaft rotatably mounted in said housing and having a gear thereon in intermeshing relation with said rack gear for rotational movement in said opening upon the transverse movement of said piston member, a separate cylinder block carried on each end of said cylinder tube closing the ends thereof and forming fluid chambers Within said tube adjacent said piston ends, tie bolts extending through each said cylinder blocks and into said housing for locating said cylinder tube in said housing and removably securing said blocks on said ends thereof, and fluid inlet means in each of said blocks providing passageways for the application of hydraulic pressure to said chambers to efifect transverse positioning movement to said piston member in said tube.

3. A remotely controlled throttle position actuator for ready attachment and removal from jet engines in an engine test stand, comprising a housing, coupling means in said housing adapted for connection to the input shaft of a throttle controller on said jet engine, a slaved hydraulic piston motor in said housing, means connecting said piston motor to said coupling means to position said controller shaft therethrough, means removably connecting said housing to said controller including a plurality of bolts extending through said housing having inner ends adapted for removable connection to said controller and exposed outer ends adapted for the application of a driving tool thereto, a cross pin extending through each of said outer ends, a latch pin for each of said bolts mounted in said housing adjacent the associated said bolt, the outer end of said latch pin being proportioned for engagement with one of said cross pins to prevent rotation of the associated said bolt, and means mounting said latch pin providing for movement thereof by the application of a driving tool to said outer end into a retracted position clear of said cross pin, and bias means urging said latch pin outwardly into an outer position in interfering engagement With said cross pin.

4. A remotely controlled actuator for attachment to and removal from a mechanism having a shaft to be controlled thereby, comprising a housing, coupling means adapted for connection to such shaft to be positioned by said actuator, a hydraulic piston motor in said housing, means connecting said piston motor to said coupling means to position such shaft therethrough, means removably connecting said housing to said mechanism including at least one threaded fastener extending through said housing having an inner end adapted for removable connection to said mechanism and an exposed outer end adapted for the application of a driving tool thereto, means forming a cross pin extending transversely of said fastener at said outer end, a latch pin mounted on said housing adjacent said fastener outer end, said latch pin being proportioned for interfering engagement With said cross pin to prevent rotation of the said fastener, said means mounting said latch pin providing for movement thereof by the application of a driving tool to said fastener outer end into a retracted position clear of said cross pin, and bias means normally urging said latch pin into said interfering engagement with said cross pin means.

5. A remotely controllable dual servo actuator comprising a housing, a pair of one-piece cylindrical tubes extending transversely of said housing and each having a central portion extending through a portion of said housing with the ends of said tubes extending outwardly of said housing, said tubes being positioned in relatively axial spaced relation with respect to said housing, a separate piston member received in each of said tubes for application of hydarulic fluid to the opposite ends thereof and having means in each of said ends forming a fluid seal with the inside Wall surface of the associated said tube, means in each of said tubes defining an opening intermediate the ends thereof and facing into said housing, means forming a rack gear on each of said piston members accessible through said tube openings, a pair of shafts rotatably mounted in said housing and each having a gear thereon received in intermeshing relation with one of said rack gears for effecting rotational movement of one of said shafts With the positioning movement of one of said piston members, a pair of cylinder head blocks having means forming tube-receiving openings therein with one each of said blocks received over the adjacent extended ends of said tubes forming a common cylinder head for said tube pairs at each of the extended ends thereof, said cylinder head blocks each having separate fluid inlet means in communication With the ends of each of said tubes for application of hydraulic fluid to the associated said piston member, and tie bolts extending through each of said blocks and into said housing retaining said blocks in closing relation to said pairs of tube ends and locating said tubes in fixed position in relation to said housing.

References Cited in the file of this patent UNITED STATES PATENTS 1,464,612 Madler Aug. 14, 1923 2,079,684 Church May 11, 1937 2,207,635 Nardone July 9, 1940 2,262,432 Rodder et val Nov. 11, 1941 2,286,661 Warner June 16, 1942 2,465,358 Curtis et al Mar. 29, 1949 2,509,991 Schenke May 30, 1950 2,782,602 Hamilton Feb. 26, 1957 2,880,580 Wallace et a1 Apr. 7, 1959 2,997,756 Stone Apr. 4, 1961 FOREIGN PATENTS 426,069 Italy Oct. 21, 1947 1,204,374 France Aug. 10, 1959 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 3 153389 October 27 1964 Bruce D. Roberts It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line 45 for "separate" read separately column 3, line 14 for "prefrably" read perferably column 6, lines 43 and 44L for "cylinder" read cylinders column 8, line o l for "sadi" read said line 65 for ":Elud" read fluid column 9 line 2O for "to" read of column 10, line l7 for "hydarulic" read hydraulic line 53 for "2,997 756" read 237L756 Signed and sealed this 30th day of March 1965 (SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patents ERNEST W. SWIDER Attcsting Officer

Claims

1. A THROTTLE VALVE CONTROL SERVO COMPRISING A HOUSING, A ONE-PIECE CYLINDRICAL TUBE SUPPORTED IN AND EXTENDING THROUGH SAID HOUSING, A DOUBLE-ACTING PISTON MEMBER RECEIVED IN SAID TUBE AND HAVING OPPOSITE PISTON ENDS IN SPACED RELATION TO THE ENDS OF SAID TUBE AND FORMING A FLUID SEAL WITH THE INSIDE WALL SURFACE OF SAID TUBE, THE MOVEMENT OF SAID PISTON MEMBER IN SAID TUBE BEING WHOLLY CONFINED TO THE AXIAL LIMITS OF SAID TUBE, MEANS IN SAID TUBE DEFINING AN OPENING CENTRALLY THEREOF AND POSITIONED INWARDLY TO SAID HOUSING, A RACK GEAR FORMED IN SAID PISTON MEMBER ADJACENT SAID OPENING, AN OUTPUT SHAFT ROTATABLY MOUNTED IN SAID HOUSING AND HAVING A GEAR THEREON IN INTERMESHING RELATION WITH SAID RACK GEAR FOR ROTATIONAL MOVEMENT IN SAID OPENING UPON THE TRASVERSE MOVEMENT OF SAID PISTON MEMBER, A SEPARATE CYLINDER HEAD BLOCK CARRIED ON EACH END OF SAID TUBE CLOSING THE ENDS THEREOF AND FORMING FLUID CHAMBERS WITHIN SAID TUBE ADJACENT SAID PISTON ENDS, TIE BOLT MEANS EXTENDING THROUGH EACH SAID CYLINDER HEAD BLOCK AND EXTENDING INTO SAID HOUSING RETAINING SAID HEAD BLOCKS IN CLOSING RELATION TO THE ENDS OF SAID TUBE AND RETAINING SAID TUBE IN FIXED AXIAL POSITION IN RELATION TO SAID HOUSING, AND FLUID INLET MEANS IN EACH OF SAID BLOCKS CONNECTED TO SAID CHAMBER PROVIDING PASSAGEWAYS FOR THE APPLICATION OF HYDRAULIC PRESSURE TO SAID CHAMBERS TO EFFECT TRANSVERSE POSITIONING MOVEMENT OF SAID PISTON MEMBER IN SAID TUBE.