US3794441A

US3794441A - Variable pitch propeller

Info

Publication number: US3794441A
Application number: US00288050A
Authority: US
Inventors: N Johnson
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-09-11
Filing date: 1972-09-11
Publication date: 1974-02-26
Anticipated expiration: 1991-02-26

Abstract

This disclosure pertains to novel means whereby the blade pitch in a propeller may be varied by employing uni-directional rotation of a propeller shaft, a portion of the power driving the propeller, and a pair of braking means. A propeller hub having a plurality of pivotally mounted blades is mounted on the propeller shaft. A blade pitch actuator member having a hub-end and a brake-end extends through the propeller shaft into the propeller hub. An eccentric slider block secured to the hub-end of the actuator member is interconnected to each of the propeller blades. An actuator gear is screw-mounted on the brake-end of the actuator member. Three pairs of planetary each pair secured to a common shaft, are mounted on the propeller shaft in substantially parallel spaced relation to the axis of rotation of the propeller shaft. One of each pair of planetary pinions is meshed with the actuator gear and further meshed with an outer sun gear secured to a first brake actuated member. The other of each pair of planetary pinions is meshed with an inner sun gear secured to a second brake actuated member. Each brake actuated member has a brake actuator means. Application of the first brake means causes the actuator gear to rotate in one direction and application of the second brake means causes the actuator gear to rotate in the other direction. Rotation of the screw-mounted actuator gear causes movement of the actuator member and eccentric slider block, thus altering the propeller blade pitch.

Description

United States Patent [191 Johnson 1 VARIABLE PITCH PROPELLER [76] inventor: Norman Allen Johnson, 5325 Tenth Ave., South Delta, British Columbia, Canada 22 Filed: Sept.l1, 1972 2'1 Appl. No. 288,050

OTHER PUBLICATIONS French 1st Addition PatentNo. 47,646; Mar. 1937; to Waseige.

Primary Examiner-Everette A. Powell, Jr.

[57] v ABSTRACT This disclosure pertains to novel means whereby the blade pitch in a propeller may be varied by employing 51 Feb.26, 1974 uni-directional rotation of a propeller shaft, a portion of the power driving the propeller, and a pair of braking means. A propeller hub having a plurality of pivotally mounted blades is mounted on the propeller shaft. A blade pitch actuator member having a hub-end and a brake-end extends through the propeller shaft into the propeller hub. An eccentric slider block secured to the hub-end of the actuator member is interconnected to each of the propeller blades. An actuator gear is screw-mounted on the brake-end of the actuator member. Three pairs of planetary each pair secured to a common shaft, are mounted on the propeller shaft in substantially parallel spaced relation to the axis of rotation of the propeller shaft. One of each pair of planetary pinions is meshed with the actuator gear and further meshed with an outer sun gear secured to a first brake actuated member. The other of each pair of planetary pinions is meshed with an inner sun gear secured to a second brake actuated member. Each brake actuated member has a brake actuator means. Application of the first brake means causes the actuator gear to rotate in one direction and application of the second brake means causes the actuator gear to rotate in the other direction. Rotation of the screwmounted actuator gear causes movement of the actuator member and eccentric slider block, thus altering the propeller blade pitch.

10 Claims,v 9 Drawing Figures VARIABLE PITCH PROPELLER I pitch propellers, fluid propulsion devices which rotate in one direction but may change the direction of fluid propulsion, fluid propulsion devices which rotate in one direction and at a substantially constant speed but may vary the direction and rate of fluid propulsion, and other such devices which are of the general character of variable pitch propellers.

The primary function of variable pitch propellers is to permit ships and boats to operate at maximum efficiency under two or more operating conditions. For example, tugs and trawlers must operate efficiently under free-running and towing conditions; submarines must operate efficiently either on the surface or submerged; pipe and cable laying vessels, mine sweepers, and target-towing craft must operate at different speeds; virtually all vessels must operate under conditions varying 1 from heavy swell to calm seas, high winds to no wind,

and open water sailing to harbor manoeuvering. A secondary function of variable pitch propellers is to provide reversability of propulsion with a uni-directional .shaft rotation, thus eliminating clutches, reverse gears, need to stop the propeller when reversing, and high starting forward loads on engine and transmission equipment. A tertiary function of variable pitch propellers, particularly where the prime mover is a deisel engine or a turbine, is to matchpropeller blade pitch with optimum engine fuel-speed characteristics for all load conditions. Further accepted advantages of variable pitch propellers are the provision of smoother speed control, higher acceleration, faster stopping, improved maneouvering, fuel economy, less engine wear, and avoidance of vibration caused at critical engine speeds.

The earliest approaches to a variable pitch propeller were devices which unshipped or feathered a propeller. Many such devices were developed in the middle of the nineteenth century. One variable pitch propeller was devised wherein the base of each blade was a short cylindrical spindle which fitted into the propeller hub; attached to each spindle was a short eccentric lever pinned to a collar mounted around the propeller shaft forward of the propeller and exposed to sea water, a

- bell-crank arrangement operated by a push-rod moving the collar fore and aft, thus varying the blade pitch. Another variable pitch propeller employed blades attached to segments of spur gears which meshed whereby rotation of one blade caused a corresponding rotation of the others; rotation of the gears was achieved by a collar sliding on the propeller shaft inside the propeller hub and protected from sea water. Still another controllable pitch propeller was devised wherein worm gears mounted on the bases of the propeller blades were rotated by a sleeve around the drive shaft; a variation on this arrangement was a rack passing through the center of the propeller shaft actuating pinions on the bases of the propeller blades.

The current art in variable pitch propellers incorporates many of the foregoing features. The most common variable pitch propellers now employ hydraulically operated servo-mechanisms. One type incorporates the servo-mechanism inside the propeller hub, fluid flow passing either through a hollow propeller shaft or through a rotating sleeve outside the propeller shaft. Another type incorporates the servo-mechanism inside or outside the propeller shaft at a location within the vessel; actuation of the propeller blades is achieved by either a push-rod inside a hollow propeller shaft or by a sleeve outside the propeller shaft. Such devices employing hydraulic servo-devices require continuous auxiliary power, are complex in structure and operation, require troublesome dynamic fluid distribution systems, are difficult to override mechanically, do not permit easy visual inspection, and are often dangerously unreliable. I

My invention herein disclosed overcomes many of the short-comings of hydraulically operated servomechanisms by its structural and operational features. It employs positive mechanical structure whereby propeller blades pivotally mounted in a hub are pivotally actuated by a blade pitch actuator member which may be either a rod inside a hollow propeller shaft or a sleeve outside the shaft. Rotation of the actuator members in either direction or slidable movement of the member fore and aft may be used to pivotally actuate the propeller blades. A pair of brake actuated members mounted on a propeller power shaft having unidirectional rotation are interconnected to the blade pitch actuator member whereby the actuator member may be either rotated or moved in one direction by a first brake actuator means applying a brake force to one of the pair of brake actuated members and rotated or moved in the other direction by a second brake actuator means braking the other of the pair of brake actuated members. In this way the propeller prime mover is used directly to alter the propeller blade pitch and energy is required only at the time a pitch change is made. Movement of the blade pitch actuator member with respect to the propeller shaft provides a direct positive mechanical measure or read-out of propeller blade pitch. The power of the propeller prime mover is used directly by the pair of brake actuator means and actuated members to alter propeller blade pitch. The pitch varying mechanism is enclosed within the vessel. A gearing system comprising an actuator gear, a pair of planetary pinions, an inner sun gear and an outer sun gear is disclosed herein whereby the movement of the brake actuated members may be modified or reduced in transmission to the blade pitch actuator member; the pinion shaft provides a positive means for mechanically overriding the brake actuated members to set the propeller blade pitch in the event of a control failure or failure of the brake actuator means. Structure is provided whereby an axial force means creates friction between at least two of the parts of my invention which rotate with the propeller shaft and move with respect to one another, thereby maintaining a propeller blade pitch setting when neither of the brake actuator means are energized. A means is devised whereby the various components of the disclosed embodiment of my invention may readily be moved with respect to one another .axially along the propeller shaft thus permitting visual inspection of the primary components thereof. Further structure has been provided whereby the fluid power of a control circuit may be used directly to operate the brake actuator means, the positive mechanical pitch read-out directly operating a pair of feed-back pressure varying valves.

Therefore it is one object of my invention to provide a variable pitch propeller wherein uni-directional rota-' tional energy of a propeller shaft is employed to effect a change in propeller blade pitch.

It is another object of my invention to provide structure embodying -a pair of brake means, each having a brake actuated member and a brake actuating means,

whereby the uni-directional rotational energy of a propeller power shaft is expended only when a changein propeller blade pitch is required, one brake means producing forward pitch and the other brake means producing reverse pitch.

It is yet another object of my invention to provide structure whereby a blade pitch actuator member interconnects a plurality of propeller blades pivotally mounted in a hub means to a pair of brake means, actuation of one of the pair of brake means producing either rotation or axial movement of the actuator member in one direction and actuation of the other of the pair of brake means producing either rotational or axial movement of the actuator member in the other direction.

' A further object of my invention is to provide gearing structure comprising an actuator gear, a pair of planetary pinions, an inner sun gear and an outer sun gear, whereby rotational movement of a pair of brake actuated members may be modified in transmission to a blade pitch actuator member.

Still a further object of my invention is to provide mechanical structure which provides a positive measure and readout of propeller blade pitch.

Another object of my invention is to provide means wherein an axial force means forces together at least two of the structural components of the invention which rotate with the propeller shaft and move with respect to each other, thereby creating mechanical friction which maintains propeller blade pitch when neither of a pair of brake actuator means is energized.

Still another object of my invention is to provide means whereby several components of the invention may be moved axially along a propeller shaft thereby to expose the internal structure of the invention to visual insepection.

It is a further object of my invention to provide means whereby the brake actuatormeans of the invention may be actuated directly by fluid power in a fluid control circuit, positive mechanical pitch read-out means actuating feed-back pressure varying valves in the control circuit.

These and further objects of my invention, which reside in the details of its structure and operation, will be evident from a study of the .following disclosure and accompanying drawings which illustrate a preferred embodiment of the invention. This embodiment is merely exemplary and is not intended to detract from the full scope of the invention as set out in the annexed claims.

In the drawings wherein like numerals refer to like parts:

FIG. 1 is a plan view of my invention in a vessel depicting a propeller shaft means mounted in a stern tube, a propeller hub means outside the vessel, and a pitch varying mechanism inside the vessel;

FIG. 2 is a sectional elevation of the pitch varying mechanism taken substantially along line 2-2 in FIG.

FIG. 3 is a partial sectional elevation of the pitch varying mechanism taken substantially along line 3--3 in FIG. 1;

FIG. 4 is a partial sectional elevation of the pitch varying mechanism taken substantially along line 4-4 in FIG. 1; I

FIG. 5 is a partial sectional elevation of a pitch readout mechanism taken substantially along line 5-5 in FIG. 1;

FIG. 6 is a plan view of the pitch read-out mechanism taken substantially along line 66 in FIG. 5;

FIG. 7 is a sectional elevation of the propeller hub means taken substantially along line 7 7 in FIG. 1;,

FIG. 8 is a sectional elevation of the propeller hub means taken substantially along line 88 in FIG. 1;

FIG. 9 is a schematic fluid power control circuit depicting one mode of operation of my invention.

Turning now to the drawings, FIG. 1 shows a variable pitch propeller, generally denoted by the numeral 20, having a propeller hub means 21 secured to propeller shaft means 22 by bolted flange 23. Pivotally mounted in hub means 21 are a plurality of propeller blades 24. Propeller shaft means 22 is rotatably mounted in a vessel by means of stem-tube 25 of conventional design and structure. End 26 of shaft means 22 is interconnected to the output shaft of a prime mover such as a deisel engine or gas turbine. Incorporated in propeller shaft 22, by means of oil-injection friction coupling 27 and bolted flange coupling 28, both couplings of conventional design, is propeller blade pitch varying mechanism generally indicated by the numeral 29. Pitch varying mechanism 29 comprises a pair of brake means 30 and 31, propeller blade pitch actuator member 32 operatively mounted inside and substantially concentric with propeller shaft 22 and interconnecting blades 24 to brake mechanism 29, and blade pitch indication means 33. Brake means 30 comprises brake actuated member 34 and brake actuator means 35; brake means 31 comprises brake actuated member 36 and brake actuator means 37.

FIGS. 2, 3, 4, and 5 illustrate several views of pitch varying mechanism 29. Brake actuated

members

34 and 36 of brake means 30 and 31 are interconnected to pitch actuator member 32 by gearing means comprising an inner sun gear 38 secured to member 34 by bolts 66 and operatively meshed with a first planetary pinion 39 spline-mounted on common shaft means 40, an outer sun gear 41 forming an integral structural part ofmember 36 and operatively meshed with a second planetary pinion 42 secured to common shaft means 40, and an actuator portion comprising actuator gear 43 operatively screw-mounted on screw thread .44 at brake-end 45 of actuator member 32 and operatively meshed with pinion 42. While a single pair of

planetary pinions

39 and 42 are operative, three such pairs of pinions substantially equally spaced about shaft 22 are herein disclosed whereby to improve transmission force distribution between sun gears 38 and 41 and actuator gear 43. Planetary pinions 42 and actuator gear 43 are situate between internal coupling flange 46 and external coupling flange 47 which form integral structural parts of propeller shaft means 22 and are bolted together by bolts 65. Common shaft means 40 is rotatably mounted in

flanges

46 and 47 and has at one end a mechanical propeller blade pitch overriding means 48 comprising squared end 49 which may be turned by a manual or power wrench. Inner sun gear 38 is rotatably mounted on shaft 22 and outer sun gear 41 is rotatably mounted on internal coupling flange 46.

Extending axially from and forming an integral part of inner sun gear 38 is blade pitch indication actuator member 50. Screw-mounted on screw thread 51 is blade pitch indication actuated member 52. Indication actated member 52 is forced to rotate with shaft 22 by guide members 53 slidably mounted in guide collar 54 clamped to shaft 22 by bolts 63. Therefore, when inner sun gear 38 is caused to rotate with respect to shaft 22 by either brake actuated

member

34 or 36, then indication actuated member 52 moves axially along shaft 22 thereby providing a positive measure of propeller blade pitch. A non-rotating follower 55 is clamp-mounted by means of bolts 64 upon indication actuated member 52 and moves axially therewith. In FIG. 6, follower 55 actuates a pair of fluid power feedback or read-out

pressure varying valves

56 and 57 mounted in valve bracket 133; one valve indicates forward pitch while the other indicates reverse pitch.

valves

56 and 57 increase fluid pressure output proportionately as valve spools 58 and 59 are depressed; cam follower means 60, slidably mounted in valve bracked 133 and having rollers 61, depress either spool 58 or spool 59, depending on which way cam 62 is moved by follower 55.

Axial force means 67 comprising mechanical compression spring means 68, bearing between recess 134 of guide collar 54 and bearing 135 operatively connected to indication actuator member 50, forces brake actuated member 34 to bear axially upon friction flange 69 of brake actuated member 36 at friction junction 104, member 36 bearing axially upon external coupling flange 47 at friction junction 105. Whereas the rotary moments of inertia of

members

34 and 36 should whenever possible be such that their inertial forces on

pinions

39 and 42 are substantially equal, the friction between

members

34 and 36 and between member 36 and flange 47 caused by axial force means 67 will maintain a given pitch setting in spite of changes in rotational speed of shaft 22. Further, this friction combined with the inherent friction forces in screw thread 44 will resist pitch changing forces eminating from an eccentric or changing center of propulsion pressure at propeller blades 24. Still further, this friction will determine the amount of energy expended by brake means 30 and 31 as well as the rate at which propeller blade pitch is altered by brake means 30 and 31.

Spring means 68 may be compressed, for setting and assembly purposes, between collar 54 and indicator member 52 by means of collar holes 70 and studs or bolts threaded into holes 71 of actuated member 52. Once collar 54 is clamped in place on shaft 22 by bolts 63, the bolts or studs in holes 71 must be slacked off or removed to permit operative indication movement of member 52 with respect to collar 54.

It should be noted that for assembly purposes and for visual inspection of inner sun gear 38 and pinions 39, collar 54 may be loosened from shaft 22 and brake actuated member 34 and sun gear 38 moved axially along shaft 22 away from internal flange 46. Brake actuated member 36 bearing rotatably upon internal flange 46 at junction 72 and the internal diameter of surface 72 on member 36 being less than the internal diameter of outer sun gear 41, brake actuated member 36 may be moved axially along shaft 22 away from external flange 47, thereby exposing pinions 42 and actuating gear 43 to visual inspection.

FIGS. 3 and 4 illustrate brake means 30 and 31 wherein each of brake actuated

members

34 and 36 include a disc portion 73.

Brake actuator members

35 and 37 are caliper means adapted to discs 73. Each caliper comprises fluid operated linear actuator 75 pivotally interconnected to one end of each of a pair of actuating levers 76 by means of pins 77. Each of levers '76 is pivotally mounted in mounting bracket 78 by pin 79 and pivotally interconnected to a brake shoe 80 by pin 81.

Caliper mounting bracket 78 is fixed with respect to shaft 22, being mounted on a portion of a ship hull schematically denoted by the numeral 74. Hence, energization of linear actuator 75 causes shoes 80 to squeeze and thus brake the disc 73 therebetween. In this way, an external braking torque may be applied at will to either brake actuated

members

34 and 36, thereby producing propeller blade pitch altering rotation of

members

34 and 36 with respect to shaft 22.

The braking force or torque which brake actuator means 37 imparts to brake actuated member 36 may be the same or different from that imparted to brake actuated member 34 by brake actuator means 35, depending upon the forces required in blade pitch actuator member 32 to effect a change in propeller blade pitch, the magnitude of friction forces created by axial force means 67, the transmission or gearing and screw thread speed change ratio between

members

34 and 36 and blade pitch actuator member 32, and the required rates of pitch change into forward pitch and reverse pitch. These braking forces or torques will be operatively determined by the fluid pressures employed in linear actuators 75 and the leverage ratio of levers 76.

Turning now to the structural details of the propeller hub means 21, FIGS. 7 and 8 show two sectional views of the hub blade portion 82 secured to propeller shaft flange 23 by a plurality of bolts 83. The aft-end of hub means 21 comprises a streamlined cover 84 secured to hub blade portion 82 by a plurality of bolts 85; cover 84 permits access to the inside of hub means 21 for assembly and inspection purposes.

Each of our propeller blades 24 comprises a base portion 86 having a spindle or pilot portion 87 pivotally mounted in spherical portion 88 of hub portion 82; spherical portion 88 permits blades 24 to pivot without disturbing the streamlined contour of hub means 21. Blades 24 are secured to a blade actuator plate 89 by a plurality of bolts 90. Each actuator plate 89 has on its underside an eccentrically located pin 91 pivotally mounted in a substantially rectangular slider 92. Slider 92 is slidably mounted in slots 93 in blade actuated portion 94 of blade pitch actuator member 32. Actuated portion 94 is secured to actuator member 32 by threaded nut 95. It will be evident to one skilled in this art that movement fore and aft of actuated portion 94 will carry sliders 92 and pins 91 in an are described about the pivotal axis of each of blades 24, thereby pivotally actuating and operatively varying the pitch of propeller blades 24.

Whereas stern-tube 25 of conventional design is adapted to prevent water entering a vessel around the periphery of propeller shaft 22, means should be provided to prevent water entering hub means 21 and thereby passing into shaft 22 around actuator member 32. Therefore, sealing compound, packing, or seals should be used in the cover-hub junction 96 at bolts 85 and flange-hub junction 97 at bolts 83. Further, packing or seals 98 and 99 between actuator member 32 and hub portion 32 and shaft 22 may be employed. Dynamic sealing means 100 should be employed to prevent sea water entering hub means 21 around base 86 of blades 24. Static seals or packing 101 should be used around bolts 90, depending on the location of sealing means 100.

Lubrication in hub means 21 may be provided in a variety of ways including continuous pressurized oil flow through actuator member 32 or shaft 22. However, for most practical applications where the materials employed in hub means 21 and shaft 22 are not subject to corrosion, chamber 102 of hub means 21 should be packed with a suitable marine grease or lubricant. Likewise, gearing chamber 106 of pitch varying mechanism 29 may be lubricated by initial and periodic grease packing, circulating oil, or periodic greasing by means of grease fittings 103. It will be evident to one skilled in this art that lubriation of hub means 21 and pitch varying mechanism 29 will most often be a choice in design dictated in large measure by the circumstances in which my invention is employed. It is worth noting however, that friction generating surfaces at

junctions

104 and 105 of pitch varying mechanism 29 (FIG. 2) should be either compatible with the lubricant used in gearing chamber 106 or operatively sealed therefrom.

Operation of my invention will be understood from a-study of FIGS. 1 through 8. Consider that the propeller shaft isdriven by a prime-mover in direction 136 of FIG. 3 and 4, that is, in a counter-clockwise direction looking aft along shaft 22. Therefore, looking at typical blade 107 in FIG. 1, it is clear that water is propelled in direction 108, propeller blades 24 thus having forward pitch. Consider further that actuator member thread 44 and pitch indicator member thread 51 are both conventional right-hand screw threads. Still looking aft along propeller shaft 21, actuation of brake means 30 causes inner sun gear 38 to rotate in a clockwise direction with respect to shaft 22, pinions 39 and 42 to rotate in a counter-clockwise direction, and actuator gear 43 to rotate in a clockwise direction with respect to actuator member 32. Therefore, actuator member 32 is moved in direction 109 and blades 24 are pivoted typically in direction 110 of blade 107, thus increasing propeller blade forward pitch. Actuation of brake means 31 causes outer sun gear 41 to rotate in a clockwise direction with respect to shaft 22,

pinion

39 and 42 to rotate in a clockwise direction, and actuator gear 43 to rotate in a counter-clockwise direction with respect to actuator member 32. Therefore, actuator member 32 moves in direction 111 and blades 24 are pivoted typically in direction 1 12 of blade 107, thus decreasing propeller forward pitch and ultimately producing reverse pitch.

As to pitch indication, rotation of inner sun gear 38 in a clockwise direction with respect to shaft 22 causes pitch indication actuated member 52 to move in direction 113. Rotation of outer sun gear 41 in a clockwise direction causes, through

pinions

39 and 42, counterclockwise rotation of inner sun gear 38. Counterclockwise rotation of inner sun gear 38 causes pitch indication actuator member 50 to move indicator actuated member 52 in direction 114. The position of indicator member 52 with respect to shaft 22, collar 54, or the ship hull 74 provides a positive mechanical measure or read-out of propeller pitch. This positive measure of propeller blade pitch may be transmitted to a remote location by various electrical, pneumatic, hydraulic, or mechanical control means; as previously described, movement of indicator member 52 and follower 55 may be adapted to actuate fluid pressure varying

control valves

56 and 57, as shown in FIGS. 5 and 6.

FIG. '9 schematically illustrates my invention incorporated in a pneumatic control circuit 130. Shaft 22 is driven by engine 1 15 having engine speed governor and automatic load control 116. The control circuit employs a duct network 129 wherein air enters the system in direction 131 and first passes through filterlubricator 132-. A single lever engine and propeller pitch control 117 comprises fluid pressure varying

control valves

118, 119, and 120, respectively controlling forward propeller blade pitch, engine throttle and speed, and reverse propeller pitch.

Pressure varying

control valves

56 and 57 provide control feed-back signals respectively as to forward and reverse propeller blade pitch; these signals may be transmitted to a control station for a visual read-out and are shown interconnected by means of two-

way check valves

121 and 122 to pilot-operated springcentered four-way control valve 123. Control valves 118 and set the maximum allowable propeller pitch setting by means respectively of pressure regulating relay valves 124 and 125; the maximum pressures established by

valves

118 and 120 are modifed or overridden by a pressure signal from pressure varying control valve 126 on engine load control 116. Hence, when the propeller blade forward pitch setting pressure signal from valve 56 is substantially equal to the pressure signal from valve 118, subject to modification in valve 124 by a signal from valve 126, then the spool of valve 123 is spring centered and both brake actuator means 35 and 37 are de-energized. If the pressure signal from valve 124 drops below that produced by valve 56, then the spool of valve 123 shifts in direction 127, brake actuator means 37 is energized and propeller blade pitch is reduced. If the pressure signal from valve 124 is greater than that from valve 56, then the spool of valve 123 shifts in direction 128, brake actuator means 35 is energized and propeller blade pitch is increased. Likewise it can readily be shown that reverse propeller blade pitch is operatively controlled and modified by

valves

57, 120, 123, 125, and 126. Moreover, it will be evident to one skilled in this art that when the pressure signal from valve 118 is equal to zero, a forward pitch pressure signal from valve 56 actuates valve 123 whereby to energize brake actuator means 37 and reduce propeller blade pitch to zero; conversely, for a zero pressure signal from valve 120, a reverse pitch pressure signal from valve 57 actuates valve 123 whereby to energize brake actuator means 35 and reduce propeller blade pitch to zero.

It is believed that my invention of a variable pitch propeller will have been clearly understood from the foregoing detailed description of my now preferred illustrated embodiment. Various modifications, changes, additions, and equivalents may be resorted to in view of these teachings by one skilled in this art without departing from the spirit of my invention. For instance, blade pitch actuator member 32, while illustrated in the drawings as being a rod slidably mounted inside hollow shaft 22, it might instead be rotatably mounted and may be either a sleeve outside shaft 22 or one or more rods mounted adjacent and substantially parallel to to actuator member 32; both

members

34 and 36 might be meshed with pinion 39 while pinion 42 actuates only gear 43; the pitch diameters of inner and outer sun gears 38 and 41, pinions 39 and 42, and actuated gear 43 may be reasonably varied to accommodate thrust requirements in actuator member 32 as well as the required rates of reverse and forward pitch change. Whereas brake means 30 and 31 comprise disc actuated portions 73 and brake actuator means 35 and 37 comprise caliper means adapted to discs 73, it is entirely feasible to employ band, block, plate, electromagnetic, and fluid friction brake means; moreover, brake means 30 and 31 may be actuated by pneumatic, hydraulic, electrical, mechanical, or manual means. Whereas a measure of propellerblade pitch is provided by inner sun gear 38, clearly such measure or pitch read-out might be obtained from outer sun gear 41 or directly be measuring the movement of actuator member 32 with respect to shaft 22. Whereas axial force means 67 comprises mechanical spring means 68, fluid operated linear actuator means, preset or controlled at will, might be employed; moreover axial force means 67 might be employed in combination with either outer sun gear 41, actuator gear 43, or pinions 39 and 42. Whereas a simple slider lock arrangement comprising block 94, slider 92, and blade actuator plate 89 is illustrated in the drawings as interconnecting blade actuator member 32 to propeller blades 24, a variety of bellcrank systems, linkage arrangements and gearing systems might likewise be employed. Whereas hub means 21 is flange mounted on shaft 22, other mounting means employing tapers, keyways, and screw threads are available. Therefore, whereas a choice between the foregoing variations, modifications, changes, additions, and equivalents falling within the true scope of my invention will depend largely upon the circumstancs in which my invention is used, it is my express intention that no limitations be implied and that the hereto annexed claims be given the broadest interpretation to which the language fairly admits.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A variable pitch propeller comprising a hub means secured to a propeller shaft means, a plurality of propeller blades pivotally mounted in said hub means and operatively connected to a blade pitch actuator member having a hub-end and a brake-end, a pair of brake means each comprising a brake actuator means fixed with respect to said propeller shaft means and a brake actuated member rotatably mounted on said propeller shaft means, an actuator gear operatively mounted on said brake-end of said blade pitch actuator member, a pair of planetary pinions operatively secured to a common shaft means, said common shaft means rotatably mounted on said propeller shaft means, an outer sun gear secured to one of said brake actuated members, an inner sun gear secured to the other of said brake actuated members, said pair of planetary pinions operatively meshed with said actuator'gear and said inner and outer sun gears, whereby actuation of one of said brake means produces forward pitch in said plurality of propeller blades and actuation of the other of said brake means produces reverse pitch in said plurality of propeller blades.

2.. A variable pitch propeller as defined in claim 1 wherein said blade pitch actuator member further comprises an actuated portion secured against rotation to said hub-end, said actuator gear screw-mounted on said brake-end, said plurality of propeller blades interconnected to said actuated portion.

3. A variable pitch propeller as defined in claim 1 wherein said blade pitch actuator member further comprises an actuated portion screw-mounted on said hubend, said actuator gear secured against rotation to said brake-end, said plurality of propeller blades interconnected to said actuated portion.

4. A variable pitch propeller as defined in claim 1 wherein one end of said common shaft means extends outside said propeller shaft means and further comprises a mechanical propeller blade pitch overriding means.

5. A variable pitch propeller as defined in claim 1 wherein a blade pitch indication actuator member is interconnected to one of said sun gears, a blade pitch indication actuated member screw-mounted on said blade pitch indication actuator member for axial movement with respect to said propeller shaft means, said axial movement providing a measure of pitch of said plurality of propeller blades.

6. A variable pitch propeller as defined in claim 1 wherein friction between said propeller shaft means and said blade pitch actuator member maintains the pitch setting of said plurality of propeller blades when neither of said pair of brake means is actuated.

7. A variable pitch propeller as defined in claim 1 wherein at least one of said pair of planetary pinions and said inner and outer sun gears and said actuator gear and said brake actuated members is also a friction member, axial force means forcing together said friction member and said propeller shaft means producing friction, said friction maintaining the pitch setting of said plurality of propeller blades when neither of said pair of brake means is actuated.

8. A variable pitch propeller as defined in claim 1 wherein at least two of said pair of planetary pinions and said inner and outer sun gears and said actuator gear and said brake actuated members form a pair of friction members, axial force means forcing together said pair of friction members producing friction, said friction maintaining the pitch of said plurality of propeller blades when neither of said pair of brake means is actuated.

9. A variable pitch propeller as defined in claim 1 further comprising blade pitch indication means interconnected to said blade pitch actuation member, a pair of pressure varying control valves interconnected to said pitch indication means, said brake actuator means of each of said pair of brake means including a fluid powered caliper means, a fluid power control circuit including a single lever control and a pair of pressure regulating relay valves and a four-way spring-centered pilot-operated control valve.

10. A variable pitch propeller comprising a hub means secured to a propeller shaft means, a plurality of propeller blades pivotally mounted in said hub means and operatively connected to an actuated portion opertor means fixed with respect to said propeller shaft means, said pair of planetary pinions operatively meshed with said inner and outer sun gears and said actuator gear, whereby actuation of one of said brake means produces forward pitch in said plurality of propeller blades and actuation of the other of said brake means produces reverse pitch in said plurality of propeller blades.

Claims

1. A variable pitch propeller comprising a hub means secured to a propeller shaft means, a plurality of propeller blades pivotally mounted in said hub means and operatively connected to a blade pitch actuator member having a hub-end and a brake-end, a pair of brake means each comprising a brake actuator means fixed with respect to said propeller shaft means and a brake actuated member rotatably mounted on said propeller shaft means, an actuator gear operatively mounted on said brake-end of said blade pitch actuator member, a pair of planetary pinions operatively secured to a common shaft means, said common shaft means rotatably mounted on said propeller shaft means, an outer sun gear secured to one of said brake actuated members, an inner sun gear secured to the other of said brake actuated members, said pair of planetary pinions operatively meshed with said actuator gear and said inner and outer sun gears, whereby actuation of one of said brake means produces forward pitch in said plurality of propeller blades and actuation of the other of said brake means produces reverse pitch in said plurality of propeller blades.

2. A variable pitch propeller as defined in claim 1 wherein said blade pitch actuator member further comprises an actuated portion secured against rotation to said hub-end, said actuator gear screw-mounted on said brake-end, said plurality of propeller blades interconnected to said actuated portion.

3. A variable pitch propeller as defined in claim 1 wherein said blade pitch actuator member further comprises an actuated portion screw-mounted on said hub-end, said actuator gear secured against rotation to said brake-end, said plurality of propeller blades interconnected to said actuated portion.

10. A variable pitch propeller comprising a hub means secured to a propeller shaft means, a plurality of propeller blades pivotally mounted in said hub means and operatively connected to an actuated portion operatively mounted on one end of a blade pitch actuator member, an actuator gear operatively mounted on the other end of said actuator member, a pair of planetary pinions operatively secured to a common shaft means, flange means operatively secured to said propeller shaft means, said common shaft means rotatably mounted on said flange means, an outer sun gear secured to a first brake actuated member, an inner sun gear secured to a second brake actuated member, each of said first and second brake actuated members having a brake actuator means fixed with respect to said propeller shaft means, said pair of planetary pinions operatively meshed with said inner and outer sun gears and said actuator gear, whereby actuation of one of said brake means produces forward pitch in said plurality of propeller blades and actuation of the other of said brake means produces reverse pitch in said plurality of propeller blades.