US3356156A - Hydraulically controlled variable pitch blade - Google Patents

Description

Dec. 5, 1967 T. C..REiD 3,356,156

HYDliAULIC/XLLY CONTROLLED VARIABLE PITCH BLADE Filed Oct. 12, 1965 4 Sheets-Sheet 1 I NVENTOR.

fi/Mw/ZE 6. 25/0 Dec. 5, 1967 T. c. REID 3,356,156

HYDRAULICALLY CONTROLLED VARIABLE PITCH BLADE Filed Oct. 12, 1965 4 Sheets-Sheet 2 I NVENTOR ATTOR KEYS.

Dec. 5, 1967 T. c. REID 3,356,156

HYDRAULICALLY CONTROLLED VARIABLE PITCH BLADE Filed Oct. 12, 1965 4 Sheets-Sheet 5 Z8 Z2 M //6 //6 54 [4 /aa 20 M 3 /46 4a 1 I02 4 I40 x g m /v 5 2 m s '5 :1: I I I I i s 300 Q 302 Z k 5/0 I 4320 3/5 306296 3/ o 30 I NV EN TOR Mama 6 25/0 BY i W ATTORNEY S.

United States Patent 3,356,156 HYDRAULICALLY CONTROLLED VARIABLE PITCH BLADE Theodore C. Reid, 3887 12th St., Sacramento, Calif. 95822 Filed Oct. 12, 1965, Ser. No. 495,063 2 Claims. (Cl. 170-16031) ABSTRACT OF THE DISCLOSURE A propeller hub assembly for changing the pitch of propellers mounted thereon, the hub assembly including means journalling the stub shaft of each propeller for rotation on the hub about the longitudinal axis of each said shaft and with each stub shaft being disposed adjacent the ends of compartments formed internally of the hub, each stub shaft having blades fixed thereon corresponding to the number of compartments adjacent each stub shaft and being freely swingable therein; the invention further including mechanical means disposed in the hub and connecting the adjacent ends of the sutb shafts to effect contra rotation of one relative to the other; and, the hub being ported to admit and expel hydraulic fluid to and from the chambers on selected sides of the blades to effect the turning movement of the stub shafts and, consequently thereby vary the pitch of the propellers connected thereto.

Specification This invention relates to a rotatably mounted blade and hydraulic means for varying the pitch thereof, and more particularly to a ships propeller, outboard motor propeller, airplane propeller, turbine blade or the like wherein the bite of the rotating propeller into the surrounding environment may be varied in response to operator commands.

Variable pitch propellers, are, of course, Well known in the prior art and are utilized on various mechanisms for various advantages. For example, outboard motors have been provided with variable pitch propellers to enhance maneuverability in close quarters such as moving in narrow channels. Variable pitch propellers are also used in aircraft to provide increased breaking eifect upon landing. Other applications of variable pitch blades may be found in regulating engine speed and blade pitch in order to operate an engine at a most eificient rate.

An object of the instant invention is to provide a propeller or blade mounted such that the blade may be controllably rotated to vary the pitch thereof.

Another object of the instant invention is to provide a propeller associated with a hydraulic circuit for controlling the pitch thereof without the use of gears.

Still another object of the instant invention is to provide a control system for selectively changing the pitch of a propeller blade.

Other objects and advantages of the instant invention reside in the combinations of elements, arrangements of parts, and features of construction and operation, all as will be more fully pointed out hereinafter and disclosed in the accompanying drawings wherein there are shown preferred embodiments of this inventive concept.

In the drawings:

FIGURE 1 is a side elevational view of a propeller mounted on a supporting structure, certain parts being broken away for clarity of illustrations;

FIGURE 2 is a cross-sectional view of the propeller and pitch changing mechanism of the device of FIGURE 1 taken substantially along line 2-2 thereof viewing in the direction of the arrows;

3,356,156 Patented Dec. 5, 1967 FIGURE 3 is a cross-sectional view of FIGURE 1 taken substantially along line 3-3 thereof viewing in the direction of the arrows, certain passageways being omitted for purposes of clarity;

FIGURE 4 is an enlarged cross-sectional view of the pitch changing mechanism of the instant invention taken substantially along line 44 of FIGURE 3 viewing in the direction of the arrows;

FIGURE 5 is a cross-sectional view of the rotation equalizing means of FIGURE 4 taken substantially along line 5-5 thereof viewing in the direction of the arrows;

FIGURE 6 is a longitudinal cross-sectional view of the pitch changing mechanism of the instant invention taken substantially along line 6-6 of FIGURE 4 viewing in the direction of the arrows, certain passageways being omitted for purposes of clarity;

FIGURE 7 is a transverse cross-sectional view of the variable pitch blade of FIGURES 1 to 6 inclusive, taken substantially along line 7-7 of FIGURE 1 viewing in the direction of the arrows, certain passageways being omitted for purposes of clarity;

FIGURE 8 is an isometric view of the pitch changing mechanism of the instant invention, certain parts being broken away for clarity of illustration;

FIGURE 9 is a side elevational view illustrating that a propeller of the illustrated device may be rotated by a mechanical driving connection, certain parts being omitted for clarity of illustration;

FIGURE 10 is an overall organizational view of the control mechanism of the instant invention which is hydraulically connected to the pitch changing mechanism of FIGURES 1 to 8 inclusive;

FIGURE 11 is a cross-sectional view of the control system of FIGURE 10 taken substantially along line 11-11 thereof viewing in the direction of the arrows;

FIGURE 12 is an enlarged view of the handle of the 7 control mechanism of FIGURES 10 and 11, certain parts being broken away for clarity of illustrations;

FIGURE 13 is a top plan view of a valve actuating mechanism of the control system as may be seen from line 13-13 of FIGURE 10 viewing in the direction of the arrows;

FIGURE 14 is a longitudinal cross-sectional view of the valve of the control system of the instant invention taken substantially along line 14-14 of FIGURE 10 viewing in the direction of the arrows;

FIGURE 15 is an end view of the valve and valve actuating pulley of the control system of FIGURE 10 as may be seen from line 15-15 thereof viewing in the direction of the arrows;

FIGURE 16 is another end view of the control system of FIGURE 10 as may be seen from along line 16-16 thereof viewing in the direction of the arrows;

FIGURE 17 is a transverse cross-sectional View of the control handle of FIGURE 16 taken substantially along line 17-17 thereof viewing in the direction of the arrows;

FIGURE 18 is a schematic view of the control system of the instant invention and its interconnections with the pitch changing mechanism.

General construction Referring now to the drawings in detail, wherein like reference characters designate like elements throughout the several views thereof, and particularly to FIGURES 1-8 inclusive, there is indicated generally at 10 a variable pitch blade and support therefor including a structural member 12 which, in the illustrated embodiment, is a depending member from a ship or the housing of an outboard motor. Structural member 12 forms a tubular passageway 14 extending longitudinally rearwardly of the associated ship having an enlarged hydraulic motor housing 16 in which a hollow drive shaft 18 fixedly carrying a hydraulic rotor 20 is rotatably mounted in a conventional manner. Rotor 20 is connected by conventional hydraulic lines to a hydraulic power source in order to rotate shaft 18. Integral with the terminal end of shaft 1 8 is a collar 22 having internal threads 24 rearwardly of a gasket seat 26.

A substantially cylindrical hub 28 having male threads 30 thereon is received in collar 22 with an annular gasket 32 being received in seat 26 and compressed therein by the tightening of hub 28 into collar 22. Closing the other end of hub 28 is a fairing 34 providing the conventional aerodynamic shape as may be seen in FIGURE 1. Mounted internally of hub 28 is a longitudinal wall 36 forming a transverse opening 38 having an enlarged central portion 40 as will be more fully explained hereinafter. The interior of hub 28 operates with wall '36 to divide hub 28 into four sector- shaped compartments 42, 44, 46, 48, as may best be seen in FIGURES 8 and 18 with wall 36 forming three longitudinal passageways 50, 52, 54 communicating with compartments 42, 44, 46, 48 as will be amplified hereinafter. A pair of transverse aligned openings 56, 58 cooperate with transverse opening 38 in wall 36 and a pair of annular coaxial externally threaded bosses 60, 62 to form a transverse passageway in which is rotatably mounted a pair of stub shafts 64, 66 receiving an axial shaft 68 therebetwecn insuring the alignment thereof during rotation.

Stub shafts 64, 66 each carry a bearing seal 70, 72 in openings 56, 58 rendering the interior of hub 28 fluid tight and allowing rotation of shaft 64, 66 therein. Precluding transverse movement of shafts 64, 66 is a pair of apertured interiorly threaded collars 74, 76 received on annular bosses 60, 62 juxtaposed to bearing seals 78, 72. A propeller 78, 80 is fixedly secured on the terminal end of each of shaft 64, 66 by a collar 82, 84 positioned closely adjacent apertured collar 74, 76 as may be seen in FIG- URE 2. As will be more fully explained hereinafter, liquid under pressure will be forced through passageways 50, 52, 54 into compartments 42, 44, 46, 48 rotating stub shafts 64, 66 in opposite directions to position propellers 78, 80 in a desired position.

Shaft synchronization mechanism As may be best seen in FIGURES 4 and 5, a shaft synchronization mechanism shown generally at 86 is positioned within longitudinal passageway 52 and enlarged center 40 of transverse opening 38 as formed by longitudinal wall 36. Spanning longitudinal passageway 52 and parallel to stub shafts 64, 66 is a pin 88 on which is rotatably mounted a pair of pulleys 90, 92. An elongate endless member 94 is wound about pulley 90 with one leg thereof looping stub shaft 64 and leading to pulley 92 with the other end looping stub shaft 66 then leading to pulley 92. Securing endless member 94 to stub shafts 64, 66 at a location opposite from pin '88 is a pair of hookshaped connectors 96.

As will be more fully explained hereinafter, stub shafts 64, 66 will be rotated in opposite directions in order to set the pitch of propellers 78, 80 at a desirable position with shaft synchronization means 86 acting to insure that each of propellers 78, 80 rotates the same angular distance. For purposes of illustration, it is assumed that the pitch of propellers 78, 80 is changed with stub shaft 64 turning a slightly greater angular clockwise distance, as may be seen in FIGURE 5, than stub shaft 66. It will be apparent that tensions develop in elongate member 94 tending to rotate pulley 90 :in a counterclockwise direction which acts to rotate stub shaft 66 in a clockwise direction.

Pitch varying mechanism The pitch varying mechanism of the instant invention includes the utilization of passageways 50, 52, 54 as well as compartments 42, 44, 46, 48 and stub shafts 64, 66. Each of shafts '64, 66 fixedly carries a pair of balanced opposed stub blades 98, 180, 182, 104 configured to be closely received by compartments 42, 44, 46, 48. In the description of the conduits connecting passageways 50, 52, 54 to compartments 42, 44, 46, 48, the ports leading to each of these compartments will be designated as near and far as may be seen in FIGURE 18 where each compartment is provided with a visible port and one that is hidden by the interior of hub 28.

Referring now to FIGURES 6 and 18, longitudinal passageway 52 is connected by a branch line 106 to a near port 188 in compartment 42 and a branch line 110 leading to a near .port 112 in compartment 46. Longitudinal passageway 54 communicates with a far port 1 14 in compartment 48 through a branch line 116 with a branch line 118 communicating with compartment 44 through a far port 120. Central longitudinal passageway 50 communicates with enlarged center 40 of transverse opening 33 with suitable seals (not shown) being provided between stub shafts 64, 66 and transverse opening 38 to avoid leakage of pressurized fluid along the exterior of shaft 64, 66. A branch conduit 122 connects with a far port 124 in compartment 42 with enlarged center 40 with another branch conduit 126 connecting enlarged center 40 with a near port 128 in compartment 44.

Referring now to compartments 42, 44 as shown in FIG- URE 18, it will be seen that the injection of high pressure fluids through central longitudinal passageway 58 through branch conduit 122, 126 will result in the rotation of stub blades 98, 100 consequently rotating stub shaft 64 in the direction of the arrow with fluid exiting compartments 42, 44, through branch lines 106, 118 into longitudinal passageways 52, 54.

Connecting enlarged center 40 to a near port 130 of compartment 48 is a branch conduit 132 with a branch conduit 134 connecting enlarged center 40 to a far port 136 or compartment 46. It will be seen that the injection of high pressure fluids into enlarged center 40 will deliver high pressure fluids through branch conduits 132, 134 to rotate stub blades 104, 102 and stub shaft 66 in the direction of the arrow shown in FIGURE 18. Fluid in compartments 46, 48 may exit through branch conduits 110, 116 to longitudinal passageways 52, 54.

It will be seen, therefore, that the injection of high pressure fluid through central longitudinal passageway 50 will result in the changing of the pitch of propellers 78, 80. If it is desired to change the pitch of propellers 78, 80 in a direction opposite to the arrows shown in FIGURE 18, high pressure fluids will be injected through longitudinal passageways 52, 54 into compartments 42, 44, 46, 48 through ports 188, 128, 112, 130 to rotate shafts 64, 66.

As may be seen in FIGURE 6, longitudinal passage- Ways 52, 54 are arranged in parallel through an enlarged opening 138 formed by the interior of hub 28 and gasket 32. Providing fluid access to enlarged opening 138 is an exteriorly threaded conduit 140 threadably secured in collar 22. Another exteriorly threaded conduit 142 is positioned coaxially interiorly of conduit 140 and threadably secured interiorly of central longitudinal passageway 50. As may be seen in FIGURE 6, a pair of stationary Us 144, 146 rotatably receive the terminal ends of conduits 140, 142 and are equipped with suitable gaskets 148, 150 to preclude the loss of fluid around the exterior of rotating conduits 140, 142.

Mechanical drive connection As indicated previously, cylindrical hub 28 may be rotatably driven by drive shaft 18 which is fixedly secured to a hydraulic rotor 28. In the alternative as may be seen in FIGURE 9, hub 28 and collar 22 may be rotatably driven by a mechanical drive connection shown generally at 152. Mechanical drive 152 includes a hollow drive shaft 154 fixedly secured to collar 22 rigidly carrying a bevel gear 156 in driving connection with another bevel gear 158. Bevel gear 158 includes a collar 160 in which is secured a driven shaft 162 by a shear pin 164. Driven shaft 162 may be connected to a prime mover, such as a diesel engine, gasoline engine, turbine, electric motor or the like in order to drive hub 28 in a known manner.

Hydraulic control mechanism Referring now to FIGURES to 18 inclusive, there is indicated generally at 166 a control system for selectively delivering and withdrawing appropriate quantities of fluid for altering the pitch of propellers 78, 80. Control system 166 includes a pair of conduits 168, 170 connecting each of stationary Ls 144, 146 to a hydraulic cylinder shown generally at 172, 174. Each of hydraulic cylinders 172, 174 includes a cylindrical casing 176, 178 connected to conduits 168, 170 by a pair of apertured cups 180,182. Cylinders 172, 174 also include a piston 84, 186 slidably mounted in casings 176, 178 connected to a piston rod 188, 190 extending through an apertured cup 192, 194 sealing the other end of casing 176, 178.

Connecting each of conduits 168, 170 between cylinders 1'72, 174 and Us 144, 146, to a control valve shown generally at 196 are a pair of conduits 198, 200. Control valve 196 includes a casing 202 connected to a central wall 204 rotatably carrying a shaft 206 at the end of wall 204. As may best be seen in FIGURE 14, shaft 206 fixedly carries a valve blade 208 which cooperates with the interior of casing 202, central wall 204 and shaft 206 to form a pair of passageways 210, 212 communicating through an aperture 14 in which is fixedly connected a conduit 216. As may be seen schematically in FIGURE 18, conduit 216 connects control valve 196 to a source of pressurized fluid 218, such as a pressurized reservoir or pump.

As will be explained more fully hereinafter, valve blade 208 will be positioned to deliver pressurized fluid from conduit 216 to either of conduits 198, 200'. For purposes of illustration, it is assumed that valve blade 208 is located in the dotted line position shown in FIGURE 14 to deliver pressurized fluid through conduits 200, 170, 142 and central longitudinal passageway 50 into compartments 42, 44, 46, 48 to rotate stub blades 98, 100, 102, 104 in the directions shown by the arrows in FIG- URE 18 as pointed out previously. As valve 196 and blade 208 are manipulated to position blade 208 in the dotted line location of FIGURE 14, piston 184 of hydraulic cylinder 172 will be retracted to accommodate the exhaust fluids from cylinders 42, 44, 46, 48 and will flow through longitudinal passageways 52, 54 and conduits 140, 168 into cylindrical casing 176.

Control system operating device Pivotally connected to each of piston rods 188, 190 and operatively controlling valve blade 208 is a control lever shown generally at 220 having a stationary pivot shaft 222 carrying parallel spaced apart flanges 224. Rotatably mounted between flanges 224 is a hub 226 carrying a pair of balanced opposed arms 228, 230-, each of which provide a pair of outwardly converging arms terminating in a U-shaped bracket 232, 234 receiving a cylindrical connector 236, 238.

Cylindrical connectors 236, 238 each pivotally receive a pivot pin 240, 242 connected to an arm 244, 246. Each of arms 244, 246 rigidly carries a pin 248, 250 rotatably received in a circular connector 252, 254 rigidly mounted on the ends of piston rods 188, 190. As will be explained more fully hereinafter, arms 228, 230 will be pivoted about shaft 22 to selectively position pistons 184, 186 in cylindrical casings 176, 178 in order to accommodate the efliux of fluid from compartments 42, 44, 46, 48 as mentioned previously.

Valve operator As mentioned previously, control lever 220 includes a pair of fixedly mounted flanges 224 secured to pivot shaft 222. Flanges 224- constitute a portion of a pulley bracket shown generally at 256 and carry spaced apart legs 258, 260 rotatably receiving a pulley pin 262. A pulley 264 is fixedly mounted on pulley pin 262 and receives an endless member 266 thereabout which also surrounds a pulley 268 fixedly secured to valve shaft 206 by a hub connection 270. In the operation of control lever 220, pulley pin 262 will be forcibly rotated prior to the rotation of arms 228, 230 to position valve blade 208 through the movement of endless member 266 and pulley 268.

Selector handle A selector handle shown generally at 272 includes an elongate shank 274 drivingly connected to pulley pin 262 by a flexible drive connection shown generally at 276 including a bifurcated arm 278 integral pin 262 carrying a transverse shaft 280 about which is loosely received an eye 282. Eye 282 is connected to a shank 284 which forms a yoke 286 on the end thereof rotatably receiving a pin 288 pivotally mounted in a first telescoping member 290 received in a second telescoping member 292 which is in turn received in elongate shank 274. As will be amplified hereinafter, elongate shank 274 will be rotated thus turning flexible drive connection 276 resulting in the rotation of pulley pin 262.

A U-shaped bracket 294 is fixedly secured to and surrounds arm 230 and is connected to the elongate shank 274 to allow rotary movement of shank 274 therein and precluding reciprocable sliding movement therebetween. Elongate shaft 274 may be rotated about its longitudinal axis to manipulate the valve operator mechanism including pulley 264, endless member 266 and pulley 268 and rotated about pivot shaft 222 to appropriately position pistons 184, 186 through control lever 220.

As may best be seen in FIGURES 10 to 12 inclusive, elongate shank 274 fixedly carries an Operators knob shown generally at 296 on the terminal end thereof. Operators knob 296 includes a body 298 forming an enlarged coaxial opening 300 in which is received a helical spring 302. A smaller coaxial opening 304 communicates with enlarged opening 300 and reciprocably carries a plunger 306 having an enlarged flange 308 on the end thereof positioned in opening 300. A longitudinal slot 310, which communicates with smaller opening 304, receives a transverse arm 312 secured to plunger 306.

An arcuaterack indicated generally at 314 includes an annular body 316 forming a portion of the circumference of a circle carrying a plurality of spaced apart outwardly extending teeth 318 forming a plurality of notches 320 therebetween. As may best be seen in FIGURE 12, trans.- verse arm 312 is received in one of notches 320 with spring 302 insuring a tight engagement. When an operator desires to m'anpulate elongate shank 274 in order to operate valve 196 and control handle 220, it is necessary first to depress plunger 306 against the biasing forces of spring 302 thus freeing transverse arm 312 from between teeth 318. Operators knob 296 may then be rotated to manipulate valve 196 with shank 274 being rotated about pivot shaft 222 to position pistons 184, 186 within cylinders 172, 174. If it is desired to alter the pitch of propeller blades 78, to a maximum extent possible, elongate shaft 274 should be rotated such that transverse arm 312 engages the last of notches 320.

Summary of operation As a starting point it is assumed that the blades 78, 80 are positioned such that the rotation of hub 28 will impart neither forward nor rearward motion to the associated vessel. Hub 28 will be rotated by the operation of hydraulic rotor 20 as indicated from FIGURE 1 or by the rotation of driven shaft 162 as indicated in FIGURE 9. When it is desired to impart forward movement to the vessel associated with variable pitch propeller 10, operators knob 296 will be grasped by an attendant with plunger 306 being depressed to free transverse arm 312 from notch 320. Knob 296 will be rotated in the direction indicated by the arrows in FIGURE resulting in the rotation of elongate shank 274 about its longitudinal axis. Rotation of shank 274 will result in the rotation of pulley pin 262 in a like direction through flexible drive connection 276. Pulley 264, which is fixedly secured to pulley pin 262, will be rotated thus resulting in the rotation of pulley 268, shaft 206 and valve blade 208 to the dotted line position shown in FIGURE 14.

Pressure source 218 will be connected through conduits 200, 170, 142 to passageway 50 to deliver high pressure fluid to enlarge center 40 in cylindrical hub 28. The attendant will then rotate elongate shank 274 about pivot shaft 222 in the direction indicated by the arrow in FIG- URE 10 to advance piston 186 within casing 178 and to retract piston 184 within casing 176. The movement of pistons 186, 184 will result in the delivery of high pressure fluid to one side of compartment 42, 44, 46, 48 and the withdrawal of fluid from the other side thereof. More specifically, high pressure fluid will be injected through ports 124, 128 of compartments 42, 44 in the withdrawal of fluid from ports 108, 120 thereof to rotate stub shaft 64 in the direction shown by the arrow in FIGURE 18. Similarly, high pressure fluid will be delivered into ports 130, 136 of compartments 48, 46 with fluid being Withdrawn from ports 114, 112, rotating stub shafts 64, 66 in the direction shown by the arrows of FIGURE 18.

Fluid withdrawn from compartments 42, 44, 46, 48 will travel through longitudinal passageways 52, 54, conduits 140, 168 to reside in hydraulic cylinder 172. It will be apparent that the rotation of elongate shank 274 through a small arc will result in a small change in the pitch of propeller blades 78, 80 with a large arc of rotation of shank 274 resulting in a large pitch change. If the attendant desires to maintain the changed pitch angle, it is necessary only to release plunger 306 to allow transverse arm 312 to engage notch 320 corresponding to the desired pitch change.

It will be apparent that cylinders 172, 174, each of which alternatively act as a pressure source and a reservoir, equalize the influx and efllux of fluid, preferably an incompressible liquid, from compartments 42, 44, 46, 48 in order to equally rotate propeller blades 78, 80, with the input of pressurized fluid from pump 218 being merely to provide fluid make-up in the event of leakage. In the unlikely event that one of the propeller blades 78, 80 rotates a greater extent than the other, shaft synchronization mechanism or shaft rotation equalizer means 86 will act to appropriately position stub shafts 64, 66 to insure equal positioning.

It will be realized that the pressure exerted on both sides of stub blades 98, 100, 102, 104 when valve blade 208 is in the solid line position shown in FIGURE 14, will preclude a change in attitude of propeller blades 78, 80 resulting from normal force reactions thereon. In the event either of blades 78, 80 strike an immobile abutment, the pressure impulse created thereby within fluid conduits 168, 170 may exceed the discharge pump pressure causing a change in the attitude of blades 78, 80. This, of course, acts as a safety feature precluding unnecessary damage to the components variable pitch unit 10. If such a feature be found undesirable in a particular situation, a valve may be placed in conduit 216 for wholly separating pump 218 from the remainder of fluid control system 166 after the attitude of blades 78, 80 is established. Providing such a valve creates the possibility of being unable to replace fluid loss within system 166 and the associated components within housing 28 until the change of attitude of blade-s 7 8, 80 is undertaken.

When the attendant desires to reposition the pitch of blades 78, 80, it is necessary only to repeat the previous operational steps rotating operators knob 296 and elongate shank 274 in a direction opposite with respect to the arrow shown in FIGURE 10 to reverse the pitch of blades 7 8, S0 rotating shank 274 about pivot shaft 222 also in the direction opposite to the arrow shown in FIGURE 10.

It is now seen that there is herein provided an improved variable pitch propeller having all of the objects of the instant invention and others, including many advantages of great practical utility and commercial importance.

Since many embodiments may be made of the instant inventive concept, and since many modifications may be made in the embodiments hereinbefore shown and described, it is to be understood that the foregoing is to be interpreted merely as illustrative and not in a limiting sense.

I claim:

1. An apparatus for changing propeller blade pitch comprising:

support means;

a hub journalled for rotation about a first axis on said support means, said hub carrying at least two opposed propeller blades;

means journalling said propeller blades for rotation on said hub about a second axis extending substantially perpendicular to said first axis, said stub shafts being coaxially aligned with one another and having adjacent ends, said propeller blades being fixedly connected to the other ends, respectively, of each stub shaft for rotation therewith, said propeller blades extending outwardly from opposed sides of said hub and comprising extensions of said stub shafts;

means for varying the position of said propeller blades relative to their respective second axis comprising:

forming said hub with at least two internally located compartments for each of said stub shafts;

each of said stub shafts having one end of a stub blade fixedly connected thereto, the number of stub blades corresponding in number to the number of compartments provided for each of said stub shafts;

each stub blade having an opposed end disposed within one of said compartments, respectively, and being freely swingable therein;

said hub having first hydraulic fluid carrying passages formed therein and extending axially thereof, said passages at one of their respective ends being in open communiction with one end of said hub, the other ends of said first passages each being ported to open, respectively, in said compartments on opposite first sides of said stub blades whereby admission of hydraulic fluid to said compartments through said ports exerts a force on each of said stub blades to cause its associated stub shaft to rotate in contra directions relative to one another;

said hub having a second hydraulic fluid carrying passage formed therein and extending axially thereof, said second passage having an end opening in said one end of said hub and an opposed end ported to open in said compartments on the reverse second side of said stub blades, whereby admission of said hydraulic fluid to said compartments through said last named ports exerts a force on said stub blades in the opposite direction to cause each of said stub shafts to rotate in reverse contra directions;

and means for connecting said one end of said first passages and of said second passage with selective control means for controlling the direction of fluid flow through said passages.

2. Apparatus as defined in claim 1 and stub shaft rotation equalizing means comprising:

a pin mounted in said second passage and having its axis parallel to the axes of said stub shafts, respectively;

a pair of pulleys mounted on said pin for rotation therewith; and

9 In an endless member interconnecting each of said pulleys 2,661,806 12/1953 Nims et a1. 170160.31 X and the adjacent ends of said stub shafts. 2,702,602 2/1955 Van Ommeren 170-16033 References Cited FOREIGN PATENTS UNITED STATES PATENTS 5 346,563 1/1922 Germany- 1,947,654 2/1934 Moody "170-16033 X EVERETTE A. POWELL, ]R., Primary Examiner. 2,346,979 4/1944 Lilley.

Claims (1)

1. AN APPARATUS FOR CHANGING PROPELLER BLADE PITCH COMPRISING: SUPPORT MEANS; A HUB JOURNALLED FOR ROTATION ABOUT A FIRST AXIS ON SAID SUPPORT MEANS, SAID HUB CARRYING AT LEAST TWO OPPOSED PROPELLER BLADES; MEANS JOURNALLING SAID PROPELLER BLADES FOR ROTATION ON SAID HUB ABOUT A SECOND AXIS EXTENDING SUBSTANTIALLY PERPENDICULAR TO SAID FIRST AXIS, SAID STUB SHAFTS BEING COAXIALLY ALIGNED WITH ONE ANOTHER AND HAVING ADJACENT ENDS, SAID PROPELLER BLADES BEING FIXEDLY CONNECTED TO THE OTHER ENDS, RESPECTIVELY, OF EACH STUB SHAFT FOR ROTATION THEREWITH, SAID PROPELLER BLADES EXTENDING OUTWARDLY FROM OPPOSED SIDES OF SAID HUB AND COMPRISING EXTENSIONS OF SAID STUB SHAFTS; MEANS FOR VARYING THE POSITION OF SAID PROPELLER BLADES RELATIVE TO THEIR RESPECTIVE SECOND AXIS COMPRISING: FORMING SAID HUB WITH AT LEAST TWO INTERNALLY LOCATED COMPARTMENTS FOR EACH OF SAID STUB SHAFTS; EACH OF SAID STUB SHAFTS HAVING OEN END OF A STUB BLADE FIXEDLY CONNECTED THERETO, THE NUMBER OF STUB BLADES CORRESPONDING IN NUMBER TO THE NUMBER OF COMPARTMENTS PROVIDED FOR EACH OF SAID STUB SHAFTS; EACH STUB BLADE HAVING AN OPPOSED END DISPOSED WITHIN ONE OF SAID COMPARTMENTS, RESPECTIVELY AND BEING FREELY SWINGABLE THEREIN; SAID HUB HAVING FIRST HYDRAULIC FLUID CARRYING PASSAGES FORMED THEREIN AND EXTENDING AXIALLY THEREOF, SAID PASSAGES AT ONE OF THEIR RESPECTIVE ENDS BEING IN OPEN

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