US2362444A - Propeller mechanism - Google Patents

Description

Nov. 14,1944. w. J. BLANCHARD' mL '2,362,444

PROPELLER MECHANI SM 8 Sheets-Shet 14 Filed Oct. 21. 1940 4M. www

Nov. 14, 1944. w` J, BLANCHARD 1 '|A| 2,362,444

PROPELLER MEcHANIsM Filed Oct. 2l. 1943 8 Sheets-Sheet 4 C24r/s 5J: fire/Verf MAM, ,www ,1- fm, y

NOV- 14, 19445 w.`J. BLANcHARb TAL- 2,362,444

` PROPE'LLER MEcHANIsM Filed am. 21. 194:0v s sheets-sheet 5 Nov. 14, 19.44. l W. J. BLANCHARD Erm. 2,362,444

noPELLER MECHANISM Filed OG'b. 21, 1940 8 Sheets-Sheet 6 me/whom PRO-PELLER MECHANISMl n Filed oet. r21, 194e` a sheets-sheet 7 PROPELLER MECHANISM Filed Oct. 21. 1940 8 Sheets-Sheet' (j wue/wtou,

and'

Patented Nov. 14, 1944 frUNiTEfD STATES -v f, `v tessuto. PROPELI'JERMECHANISM i l r .f

Wel-neral. Blanchardand Charlesr S. J. MacNel, Dayton, Ohio, assignors, by mesme'astignnientsv to General IMotors Corporation, Detroib-Mich.,l

This invention relates'to'prop'ellers and'more particularlyto 'p ropellers*` of the tandem or dual rotation type.'

yIt `is the principal 4'object "of 'the invention `to provide a propeller comprising"twoy groups of propeller blades mountedeoaxially' and` driven oppositely 'to eachother in which provision is made for adjustingthe. pitch'ang'le setting 'of both groups o f'blades as desired.

It isv a further object te'iprmride a. "propeller of 'this character in'which the "pitch jof'ftlie two sets ef blades maybe "adjusted ywith a f pred-eter- .a` corporation ofDelaware Applieatitnoetpber121, 1940,A senti Naja-taillis @settima (atlete-135.6) t

tien; eertain ofthe partshein-'gshewn in elevationfahd others being sectioned temere clearly show the constii'tion'thereof;

- iFig. 2` is va'transversesectionalvi'ew on the line 2:2 4Vof* Figgr; shutting the hydrauhe mechanism 'ofthe rear'hub;

' f igiiis a detailisectieiilview onthelineaf-s minedeiirerentiai setting with Yrespect 'te ee-eh v'othersl'lchasto 'provide'fo'r theutilizationby the 'rear propeller of 'energyfinthe slip'stre'am'from 'f the vforward propeller tode v'elop'a maxiinu'n'r overall output andefoiency.

It is also anobject to Aprovidesuehap'ropeller in'which separate sourcesof power are'provide'd for elTecting-adjustment of the pitch of e'aollof the sets of propeller blades l'and arranged for proper vconcurrent control', I

automatically.

It is a furtherobject to provide a separate source of `hydraulic operating power for adjust'- ing the pitch of eaCho the sets'ofbla'de'sdispens-v ing with the .use of iiuitl pressure transmitting connections'between relativlyinovable parts.v

It is a still further Lobject to provide a dual' rotation propeller assembly v*in 'Which'each of the propellers hasits'own' Vhy'draulio adjusting in'h# dependently 'controlled andthe other' controlled dependently in -accordance 'withthe 'position ocicupied by the rstso that 'theftwo 'propellers aty all times occupy properrelative positions.

It is a further 'object to provide a dual frotaeither manuauy or `adjusting mechanism; y40' position in the e`ve'nt"of failure ofthe adjusting or controlimechanism.

It is a stm further 'objectfte provideadiial rotation hydraulically adjustablepropeller 'a'sser'h-` bly inwhich "the pitc'hof -bothsets of propeller blades is easily'and rapidly adjustable over'a wide range "of blade angles v'and-into a featheredfpositien. f yother `ehjeetsand advantages win be apparent from the following 'descriptio'n,V tneaccompanythe lfcirvvard hub;

Yortie. 2 shewingithepumpmeehahisfn; l

` "riep-"eis a iie'taiise'ttierrai-view eh'the'iihe t-t. -ef Fig.' l2 showing' vthe "eenstriietieh e: the 'ae-- vbroken aw'alyt "Show "the Constrlitn thereof governor springs" ved speketethe Iiiiel l-'lil ffif'igio;

' Fig. F12 gis a transverse se'tienta tiewshewiiig the adjusting mechanism eh the 1ihe iz-'fz 'ei- Fig. 1;

Fig `17fis a'view .pitiirijlitilly'i'in settien ythe.petrtiallt'7 'elvatioilwith lthe. casing removed .from

Fig; 18 is", e firent Lei'evtihai tiet ieg the' for- Ward hub with a part; 'th'er'e'obei'ng brokenaway to show-the` operating mechanism for seouring im@ W5@ 'sectional 56h fthe line f "tail settie'nai geh the. iih'e tiehi view ehthe i'ihe the position of response of the forward hub with respect to the rear hub; n

Fig. 20 is a partial detail view showing the manner in which the adjustment of the setting of the regulator valve in the forward hub is secured;

Fig. 21 is a schematic representation of the principles of control as present in this invention;

Figs. 22-24 are diagrammatic representations I y illustrative of the manner in which the regulation ofthe pitch setting of the forward hub is obtained; and f Fig. 25 is an elevational view on a smaller scale of the assembled dual rotation hub.

The invention relates to a dual rotation adjustable pitch propeller, that is one in which suitable drive mechanism is provided for operating a forward hub in one direction and a rear hub at the same speed but in the opposite direction. The blades carried by the respective hubs are -of opposite pitch so that the thrust produced by both sets of blades takes place in the same direction. The two sets of blades are mounted in tandem, and are arranged coaxially and relatively close together, ordinarily spaced apart adistance less than the radius of the blade, as shown for example in Fig. 25. It is found that such an arrangement results in balanced reaction forces andin substantially increased efficiencies particularly under high speed conditions and with high pitch settings of the blades.

In accordance with the present invention, the pitch angles of the blades of both sets are adapted to be adjusted or varied in order to secure the 'best results under all conditions of operation.

Provision is made for regulation of the assembly to a constant speed condition under varying night conditions, and for the preselection of a desired speed to be maintained within the operating range of speeds, manually or under the control of instruments. The blades may be operated and adjusted over a wide range of pitch settings varying from small angles, or from a position of negative pitch if desired, up to high operating angles and into a fully feathered position. Both sets of blades are concurrently adjustable either to the same pitch or to a pitch such that there is a predetermined differential in the setting of the two blades as found most desirable and such adjustments are effected positively and rapidly. Furthermore each hub assembly is complete in itself, each incorporating its own hydraulic system, including pressure developing, controlling, and applying mechanism. Thus there are no running joints between relatively rotating parts through which fluid operating pressure is required to be transmitted under pressure, and a highly satisfactory construction and operation are thus secured.

The invention may be utilized in conjunction with various types of adjusting mechanism for varying the pitch of the blades, and is not limited to any particular arrangement for this purpose. It is particularly adapted however for use in conjunction with the propeller mechanism shown in applicants copending applications Serial Nos. 279,530 and 279,531 led June 16, 1939, now U. S. Patents 2,307,101 and 2,307,102. For purposes of illustration, the invention will be hereinafter described as embodied in a propeller constructed generally in accordance with said copending applications. y

Referring to the drawings which disclose a preferred embodiment of the invention, there is shown an engine housing I from which there extends an inner drive shaft II and an outer concentric drive shaft I2. Suitable transmission mechanism is provided for driving these two shafts in opposite directions -and at the same speed, such mechanism not forming a part of the present invention and not being shown in the drawings,

The `rear or inner'hub indicated generally at I4 has a plurality of blade sockets I5 associated therewith in which are mounted the propeller blades I6. As shown the hub comprises three such sockets and a corresponding number of blades, it being understood that any number of blades and blade sockets may be provided as desired. The drive shaft I2 and hub I4 are provided with cooperating spline parts 2U which provide for receiving and removing the hub in proper driving relation over the shaft. It is held in place thereon by a wedge ring 2I adapted to work against a tapered ring 22 at the inner end` of the shaft. A lock ring 23 provides for retaining the ring 2l and the hub in assembled position.

The drive shaft I2 terminates within the confines of hub I4, while shaft II extends forwardly and receives thereon'the outer or forward hub 25. This hub is similarly provided with a number of blade sockets 26 shown as being the same number as provided for the rear hub, in which are mounted the several blades 21. The hub 25 and drive shaft II have cooperating spline portions 28 which provide for removably receiving the hub in operating position over the drive shaft. It is held in place by `means of wedge ring 30 working against a tapered ring 3| which is backed by a nut 32 fastened upon the drive shaft. ring 30 is retained in place by the forwardly projecting sleeve 35 in accordance with the usual propeller construction. A locking pin 36 prevents relative rotation between the sleeve 35 and the drive shaft Il, and snap ring 31 received in a groove in hub 25 provides an abutment to facilitate removal of the hub from the shaft. A sheet metal housing section 38 is preferably provided over the forward nose of the `propeller to minimize wind resistance and to enclose the end of the hollow drive shaft.l It will be noted that the inner drive shaft II is hollow, and offers no obstruction to the mounting of cannon or the like for firing through the hollow drive shaft.

In order to afford proper supportfor the forwardly extending drive shaft I I, there is provided a roller bearing 40 having an inner race 4I carried by the shaft II and held in place by nut 32 and an outer race 42 kin supporting contact with the forwardly projecting portion 43 of the inner hub I4. In this Way proper alignment and support for the two rotatingl shafts is provided.

A substantial part of the mechanism for securing adjustment of the setting of. the blades is the same in the two hubs, and accordingly attention will be' directedl to the rearor inner hub, the' construction of which will be described rst, and thereafter the differences in construction in the forward hub will be described.

Referring to Figs. 1` through'll,V the construction in vtheinner hub comprises a radially extending -plate or casting 5I) which is carried by and rotatable 'with hub 14,- being removably held in place thereon by a locking ring 5I threadedly engaged upon the hub. Attached to the outer periphery of plate 50 by means of bolts 52 is a casing or housing member 53 which together with the plate 50 forms a reservoir for receiving a quantity of pressure operating fluid.

A stationary member 55 extends into the hous- @inwardlyonlitsgpressureistroke bythe-high points onthe .camend alternatelygpressed voutwardly on fing, :being boltedf ibycmeans. of bolts'56-nto an adapter fplate: .51-connected to the engine casing or to some suitable ,non-rotating zpart. ,It ais :formed with'r an axially extending sleevepart 58 located immediately youtwardly of :sleeve 5|- and f extending adjacent plate 50, and projecting radi- .allyoutwardly thereof it is formed withra cam member 59. 'The joints or points of running con-A tactof the reservoir and this stationary member are sealed to prevent loss of fluid. For this pur- .pose 4a washer 60 'is provided,"v which is held in .l

place against the adjacent surfaces of plate 50 `and sleeve 58by compression spring 6 I, the Whole.l

being retained by aplate 62 .vboltedtothe inner 'surfaceof member'50by'meansz0f bolts 53. vAt

" the ,point of contact of the casing553 with the stationary member 55, a similar sealing -joint indicated generallyat 64 isprovided, thus assuring the maintenance of an effectively sealed reservoir for containing the operating uid. f l r vIt is found at times thatunder operating conits suction stroke by the springe. Provision is .made for; readyremoval zand replacement of ,the .spring bylmeansof .a movable cap 88 threadedzinto the ihousingnportion'15;. andrihaving .a shankuBS thereon 'for f, V,guiding spring :186 ithereover, .the

springthusbeing. easily replaceable.

:The pressure chamberfil.; of .the .pump 'com vfmunicates ',directlylby passage. 90a. .with the yinter- .mediate xchamber 9| ofthe. .valvev rmechanism 1.| .This .mechanismas shownfin Fig. 4 .also is :mountedvwithin theplate '50,.zand'comprises asuetion inletivalve 92 umounted upon va central Aguide .pin Y93 Yand resiliently .urged toward closed seating position. by;1neans .of spring.- 94. The 1 inlet rpori-,is

ditions and the.--normally resultant increase in..

temperature, air which may have leaked intofthe t ties` passing into the .fluid system.

reservoir is subject to expansion and 'may produce a pressure increase inthe reservoir. To repressure release in the form of a ball checky valve 66 resiliently urged toward seating Iposition by means of spring B1. Escape of air under pressure is permitted' through this valve, but fluid `will not escape becauseunder co-nditions of operation .the iiuid is located at thel radially Vouter .-25 lieve such pressure increase, the` reservoir at a radially inner point thereof is provided with a shown at95 ,indirect communication with the ,reservoir .fand bl'eing" located radiallyoutwardly ,fthereof sothat it willbe assured of receivinga supply of the :fluid :from .the .reservoir during operation'. If., desirediia suitable protection device .may g be .located-over.; the inlet to :prevent impuri- An voutlet or discharge .valve 96 is mounted ...upon fthe guide; pin 93 Vand .resiliently urged ltowardfseating :position `by vspring .9.1. Ity controls the discharge .fromrt-he pump chamber 9| tothe .discharge chamber. L w* Aswillibe apparent from ythe above the 'Opera- .tion of :.thepumpandfvalve mechanism is as follows. Upon the rotation ofthe hub and plate 50,

,the;pump iszcarried .around with respect to cam f `59, thus causing the-'pumppiston to be 'alternately portion ofthe reservoir and hence exerts no pressure as such upon the relief valve. Upon cooling,

should the pressure within the reservoir fall below atmospheric, air may seep into the samethroughthe sealed joints above described toequalize the pressure. y

Withinthe reservoir there is located a selfcontained pressure kdeveloping-and controlling systemso that fluid pressurev is not required to be transmitted from' a stationary or non-rotating part. of .the propeller into the hub, and hence .no packed joints-operating under high kpressure conditions are required; -Pump mechanism is rlocated within .the `housing* preferablyy comprising. afpair of pressure. developing.` pumps. These .pumpsare shownat 10, and-asillustratedinFig. 2,y are suit- .ablyspaced from Veach other arcuately so lthat vthey will function invpredetermi'ned timed relation .to each other. rEach pump has its ownasso.- ciat'ed valve mechanism 1 Land there is alsoassociated therewith acommon rrelief vvalve mechanis-m indicated generally at 12. t

Referring .now to the .l pumpV mechanism;` as shownin Fig. 55 the pump isl mounted Withinathe plate .50, a suitable elongated chamber -15 being integrally iormedlin the `plate to receivethe pump. The pump piston `80 is mounted for sliding movementv in a direction parallel with the axis of rota-f tion within .cylinder 8|. It carries at itsouter moved sinwardg-and .outward .with respect to its ,cyllnden Upon outward movement the pressure in the Valve chamber; 91| is reduced, thereby clost ing valve member 96,'and causing valve member 92 .to open to .draw fluid zthereinto.` Upon 'the return orpressure stroke of the pump, valve mem- 40 y. developed to afford proper operation, it is no longer necessary that the pump mechanism continuevto supply fluid under pressure, and its'continued operation would merely result in unnecessary working and heating of the fluid. In order tok relieve the action under such circumstances,

end a .cross-shaft. 82 havingarms 83. v.projecting therefrom which yarey guided in slots 84' formed within vthe outer end of the; cylinder 8|. :This

construction provides -for reciprocating movement of the pistonpreventing angular or twisting motion, thereof. Aeompression spring Sli-.normally urges the ,pump piston outwardlyofl thek cylinder, and intosuchpositionthat roller :81, ,carried upon the .cross-shaft 82,-r'juns incontinuous bearing :en-A

gagement withxed cam .59. -Thel'tcamispreferablyprovided with; two lobes or highpoints, such that lupon operationofthe hub and .with thev pump the vrelief valve 12 is provided. As shown, this valve isalsohjmounted within the plate` 50, and comprises a movable piston member |00Xhaving a land` |0| lthereonand a second land |02 of..

greater diameter. 'Theipiston is movable within aI cylinder |03 having proper internal diameter *to receive the two lands therein. The cylinder is ported at v| 04 inthe range'of land I 0| and a connectiony |05 leads thereinto from the valve cham- A second port |06 in the range" ofy land .|02 lis provided and lconnection |01 leads theret .and is preferably` apertured at its outer end as I into fromA the discharge lcl'xamber 98.; The interior'ofth valve |00 may be hollowA as shown shown at' |08 in order to vpermit free inow and outow Vof the fluid therefrom as the valve moves.

Also stop plates |09 and ||0 areprovided at the inner ,and .outer :limits respectively-.of the ytravel of the valve, plate IIO being removably held in place to permit of ready removal and replacement of the valve.

Theoperation of Vthis mechanism is as follows. In the position shown in Fig. 3, land covers port |04 and hence the pump pressure from chamber 9| is not effective. However the tube |01 is openedto the space between lands |0| and |02, and the pressure of chamber 98 isftherefore effective therein. Because of the difference in the projected areas of the lands, there is a resultant force established tending to cause movement of the valve member radially inwardly. The valve body itself is subject to centrifugal force, and its weight is suitably selected to be responsive to a predetermined speed condition. As the pumpcontinues to operate, the pressure within the discharge chamber 98 builds up, and if not required for use, Areaches a maximum desired value. At this point, the force acting upon the valve body I 00 is sufficient to overcome the eiect of centrifugal force thereon and results in initiating movement of the valve body radially inwardly. As soon however as the valve begins to move inwardly, the centrifugal force effective thereon decreases because of its lesser radial distance from the axis of rotation. As a result the valve quickly is moved into its innermost position, and in .such position the land I0| uncovers the port |04 and permits fluid to flow therethrough from pump chamberv 9| directly back to the reservoir. Thus while the pump continues to operate, it merely circulates the fluid substantially without pressure and hence performs only a very small and unobjectionable amount of work.

The pressure within the discharge chamber 98 is maintained meanwhile by reason of the closing of valve member 9b which thus functions as a check valve to retain the pressure in the system. Should operating fluid be required, or upon such leakage taking place as to reduce the pressure within chamber 98, the pressure effective upon the diierential area of valve |00 becomes less than that necessary to retain it in its inner position. At this time it begins to move outward1y,.and since the centrifugal force increases with its greater radial distance from vthe axis of rotation, it immediately moves to its outermost position, completely closing relief port |04, and providing for the continued delivery of pressure fluid to the discharge chamber 98.

It will thus be seen` that the operation of the valve is unstable, and that it necessarily adopts one or the other of its two extreme positions. It will also be noted that inasmuch as the valve body is subjected to greater centrifugal force at higher speeds, it-will automatically provide for building up and maintaining a greater pressure within the discharge chamber' S8 at higher speed conditions. The actual speeds at which the valve will function are suitably selected by varying the weight of the valve, and it will be seen that it can be readily removed and replaced by a valve of different weight as required. Further the degree of pressure dro-p which will result in the outward movement of the valve body may be regulated by changing the relative diameters of lands IGI and |32, and by varying the degree of radial movement of the valve.

In order to provide for delivery ofthe pressure fluid from discharge chamber 93, a pair of tubes |25 are provided which communicate with that chamber and are located in the body of plate 50, being preferably cast to form an integral unit therewith. These tubes lead arcuately around is opposed by means of compression spring |20 acting on the opposite side of the piston, a suitable stop plate I2I being provided to limit the inner movement of the piston. In operation, the pistons are maintained in a partially depressed condition rby reason of the development and maintenance of the fluid pressure transmitted thereto by tubes ||5.l They provide a storage space of substantial capacity in the aggregate, and thus tend to reduce fluctuation in the pressure within the tube, providing more uniform vpressure conditions for use. It will also be appreciated that they afford a source of pressure for return delivery to the valve chamber to replace such leakage as may occur therein, and hence increase the periods between successive operations of the relief valve and pump mechanism as described above. As shown three of the accumulators I |1 are provided in communication with each of the tubes ||5. y

The pressure tube H5, as shown in Figs. 7 and 8, leads into the central part of a regulator valve chamber |25 carried on plate 50. The regulator valve body is shown at |26 and comprises lands |21, |28 and |29 spaced from each other by a portion of reduced diameter. Land |21 controls an outlet port |30 while land |28 controls outlet port I3l. A pressure o-perating line |32 communicates with port |30 and a pressure operating line |33 communicates with port |3I, line |32 being located radially inwardly of line |33. Pressure relief ports |25a open through the chamber |25 between the lands |28 and |29, and communicate with the reservoir. The valve body is also provided with a pin |35 at its radially outer end and in the land |29 to .which is attached an operating yoke |36 having threadedly received therein la lever arm |31.

Valve body |26 is mounted radially, and is directly subject to the action of centrifugal force, acting upon the body itself. In order to overcome the tendency of centrifugal force to move the Aand hence a constant opposing force is applied to the valve body for resisting the outward movement thereof.

In order to provide for variation in the response of the regulator valve, a variable fulcrum is provided for the lever |31. For this purpose a stud |45 is fastened to the valve casing, and projects therefrom generally parallel with lever |31. A shoe |46 is slidably adjustable along stud |45 and carries a roller |41 which rides upon the lever |31, forming a fulcrum therefor. It will be apparent that upon movement of roller |41, the effeet of the spring force'as opposing the centrifugal force acting on the valve body will be varied, since any change in the position of the fulcrum roller will produce a greater proportion of change in the lever arm of the spring than in the lever kventl axial vmovement thereof, these parts arm effective with respectto-the -valve body. Aswill' be more-'completely-described hereinafter',v

- movement ofthe rollertoward vtlle'valve body'ref sults in lessening the spring `force'eliective upony the same-thus causing the valve -body to movey outwardly 'to cause the application of fluid pressure in suchl direction aslto-bring about an increase-inthe pitchvangle of the blades;y speed then tends toi slowdown, and the centrifugal force'effective uponthev valve body to oppose that of the spring is likewise reduced so that an equilibrium orbalance point is establishedat a slower speed of rotation. The converse is equally true, movement of the fulcrfum' roller awayfrom the valve-body effecting an increase in the effect of thespring force and hence resulting in inward movementof the valve to cause application" of fluid pressure to effect a lowerpitch setting ofthe blades. Therefis a consequent greater speed-of operation, which inturn producesan increased;y centrifugal force in Aorder to again reach a bal; anced condition of.l regulation at a new speed level.Y

It will likewisebe clear that movement of the. roller towardythe valve body'sufliciently'to bring'` thel line yof action ofthe spring'force directlyK towardv the roller; or to the right .thereofI as viewed in Fig. 7,will result in the valve moving: to andremaining in its outer position thus bring-- ingv about'` the maximum increase in the pitch of theblades. This will provide'forthe adjustment thus taking axial: thrust in'- either direction.

The `forwardly projecting end of' shaft |66 is threaded vas shown in- |1| andis received within The.

oftheblades to-afully feathered position, where f accessible fors-operation from. theaircraft. As`

mounted on sleeve |5|"carried by the adapter plate51 or` other suitable stationary part, and to be v.actuated either manually or under the control of suitable instruments. -Thelevercarries' at'its lower. end a toothed sector' |53"which engages with4 the pinion |54 of a gear andpinion assemblyl rotatably'mounted'upon a. studshaft |55 and suitably journaled in the motor casing. The gear |56 `meshes with a ring 'gear |5T`mounted yfor rotation upon a stationary sleevey |58. projecting from the engine casingthe gearr being suitably, held therein by means ofv aplat'e |59 Aand snap ring |60. Meshi'nggwith.ringgear |51 ,area series. of operatingfpinions |61,A shownas comprising three pinions,each.mountedforrotationfin a. bracket |62'carriedby the adapter plate 51. The. pinions |6| are.'symmetricallylocated along theA peripheryy of ther shaft and .provide for rotating. shaftsy |63y which extends through the casing, be-. ing providedwithsu-itable sealing means |64. Each shaftu |63 sv-.providedwitha tongue andv groove' connection |65..with a second lshaft |66r which is rotatably mountedv within the. stationary1 member 55,l theftorigue.k and groove;construction`r providing for; the ready. separation of the-,two sha-ft,` sections from ,each-other; duringl assembly.` 0r disassembly of the'device as 'hub` =|'4'is removedy or replacediuponwshaf't |21? -Shaft |66 `'extends through member 55andintothe interiorof the reservoir. Atthe point where it passes through.

the wall of member 55, itis Jforrnedwith a shoulder |68; and in order to'provide forV takingl up axial thrust;A aenotched plate |69 isi bolted tothef a ringl sleeve'l12. Thesleeve is splined as shown at' |13`to the'stationary sleeve 5| in such manner that upon-the rotation of the three shafts |66; thesleeveis causedV to move axially, while being, restrained against lcircular movement. As will beapparent, this. axial movement of sleeve |12 takesfplace inaccordance with the adjusting movement of lever |50. i l

Apair'of llevers |15 are mountedwithin reservoir, conveniently through theprovision of lugs posite "sides and is caused vto move toward or away from theregulator valve to vary the effective force 'of the spring,y and'the length' of the lever arms as previouslyfdescribed.

vIt will thus be apparent that with a fixed'setting ofthe fulcrumroller |41 the regulator will tend to maintaina balancedrv position such as to bring about constant speed Operation; and `upon the superiniposing of a manualor-other control Y to vary the position o'f the fulcrum, the V regulator shown, a lever arm |50 is arranged tob'e rockably 'Y face of memberv asshowir'at: |10; Thegouter' face of vplateH 55 andl the/inner facef of plate |69 1 thus serve to confine they shoulder `|68 and tol pref tendsv to regulate to av ,different predetermined position.` n 4 A A Y The manner 4inwhich th'epressure iiuid isfdistributed through. the tubes |32 and |33, in order to bring about respectively a decrease and an increase in the'pitch setting of theblades will now bedescribed. As shown in Fig.` 8,5the two tubes y |32 and |33 are arranged infagenerallyconcentriclmannenveach makinga lcontinuous closed circuit 'upon itself; Tube I 32 is provided' with a series of three openings |85, while tube |33 is provided with asimilar series of openings |86.

Each series istequidistantly arranged and the two series are arrangedl in staggered relation with respect to each'other. These openings |85 and |86 project through the ywall of platek 50, andare locatedimmediately adjacent the walls of bladeI socketsv 5J As shown injFifg. 10,r a corresponding series'of'openings |88 'isprovided at the same diameter and inithe` same'corresponding spacing as openings that is, onefor each ofthe threeA blade sockets. A- second series v'|89'is provided correspondingly arranged with respect to vopenings |86. This provides an opening |83v and an opening l89leading into each of the 'three blade from the opening |89I into a position removed from the axis ofthe blade. Thus uid may be introduced throughline |90 into the-central portion of theblade socket and upwardly vthroughV passage |92 into the interior of va 'sleeve member Tube |9| providesfor the introduction of. fluid through passages |96 and' |96' to thespaceA cxternalrofz thesleeve |95t and inwardly of the' actual wall of the blade root. Suitable packing I 91 is provided for preventing the escape of uid from the space external to sleeve |95 and a supplypassage for the fluid is formed therethrough;

Sleeve |95 is fastened to hub I4 by means of pins |98 so that it is mounted thereon and prevented from turning with respect thereto.l At its outer end, the sleeve is provided with a packed joint 200 through which there slidably projects a hollow piston rod 20|. A piston 202 having predetermined mass is carried by the piston rod at its outer end and is arranged to operate in iiuid sealed relation within a cylinder 204. The cylinder 204 is fastened to the blade I6 by means of pins 205 so that upon rotation it will effect correspondingxotation of the blade. The piston is formed with an inwardly projecting sleeve 206, the inner face of which is arranged to engage and slide over the outer face of the stationary sleeve |95. These two faces are provided with cooperating helical spline surfaces 201, so that upon radial movement of sleeve 206, it is also caused to rotate against the xed sleeve |95. Similarly the outer surface of sleeve 206 is arranged to engage and slide over the inner surface of cylinder 204 which is suitably offset to receive the same, and these parts are provided with cooperating spiral splines 208 so that radial movement of sleeve 206 imparts additional rotational movement to cylinder 204. Thus the movement of piston 202 effects movement of its sleeve 206, and that movement causes a resultant angular or rotational-movement of the cylinder 204 to take place, in accordance with the sumof the angular movements produced by the two sets of cooperating spline surfaces. The length of `the cooperating spline surfaces and the pitch angles of the respective helixes are selected as desired to give the proper degree of movement for adjusting the pitch of the blades from a low or negative pitch position, through the operating range to a high pitch or feathered position.` If desired the mechanism disclosed in copending application Serial No. 279,530 now Patent 2,307,101 may be utilized for this purpose. l

The blade I 6 is retained in its socket I5 by means of a collar 2|0 threaded on to the root of the blade and engaging a series of stacked ball bearings 2 I I which are held within the socket by an outer threaded collar 2|2 suitably locked in place by a lock 2|3. The blade is additionally guided for rotation upon its own axis by ball bearing 2|5, thereby providing an antifriction support for the blade upon the hub I4. In order to enclose the hub, an annular plate orcasting 2|6 is bolted against the hub, providing for retaining lubricant, etc. within the same.

It will be apparent from the foregoing that introduction of pressure operating fluid into the interior of sleeve |95 through the opening |92 provides for the application of that fluid through the hollow piston rod 20| to the outer surface of piston 202. Hence ,such application will force the piston inwardly. The spline teeth 201 and 208 are so arranged that such inward movement of the piston produces a decrease in the pitch of the blades. Conversely when the pressure is supplied through port |3|, tube |33, openings |86, |89, and tube |9| to the outside of the sleeve 'I 95, it flows upwardly over the respective spline teeth 201 and 208 to effect the lubrication thereof, and then into the space beneath piston 202 with resultant outward movement thereof. Upon such movement the patch of the blades is increased.

It will be understood that whengpressure is applied upon one side or in one direction, the pressure is simultaneously relieved upon the other side of the piston, and the fluid in that part of the system allowed to discharge back into the reservoir by the uncovering of the corresponding port. For example when valve |26 moves outwardly tov supply pressure fluid to tube |33, land |21 moves to uncover port |30, and fluid from tube |32 is then free to fiow through the open port and back into the reservoir. Each end of valve chamber |25 is open'and in communication with the reservoir for return discharge of fluid from either tube.

Each blade thus has its ownpressure actuating mechanismjand is arranged to be operated through the positive application of hydraulic pressure in each direction to effect both pitch increase and pitch decrease. In order to maintain uniform control over the position of all the blades, each blade is provided with a beveled gear sector 220 which meshes with a ring gear 22|,

suitably mounted upon ball bearing 222 carriedl by the forwardly projecting part 43 of hub I4. Thus gear 22| operates as a synchronizing mechanism to assure that the position of all the indi- `vidual blades in the hub will be the same at all times.

As described in the above referred to application Serial No. 279,530, now Patent 2,307,101, this arrangement provides for substantially balancing the forces effective upon the blade within a predetermined position of normal flight settings. Certain forces acting upon the blade tend to cause decrease in the pitch thereof, but in the preferred arangement these forces are not relied upon to return the blades to a lower pitch position. The

weight of piston 202 is preferably chosen so that the effect of centrifugal force thereon tending to move the piston outwardly and hence to increase the pitch of the blades is substantially balanced with the forces tending to cause decrease in the pitch of the blades, at a preselected point or range within the normal operating range of blade positions. Positive application of pressure is utilized to overcome the inherent frictional forces present, and to adjust the pitch of the blades to a proper setting in both directions while provision is made for assuring the blades remaining in a satisfactory operating position even in the event of complete failure of the uid pressure system and the control mechanism.

The mechanism in the forward hub is in many respects the same as that described above. Except as otherwise indicated the elements of structure in the forward hub similar to those of the rear hub have been given reference characters of the same order, but increased by 2003` Thus, the front hub Acarries an annular plate 250 similar to plate 50 carried by the rear hub. This plate is retained in position on hub 25 by means of locking ring 25| threadedly received upon the h'ub. Bolts 252 removably attach a covering or housing member 253 to the plate 250 forming therewith areservoir for receiving a quantity of pressure operating fluid. A sleeve member 255 is bolted to cover plate 2|6 rotatable with rear hub I4 and projects Within the reservoir of the front hub. It is formed with an axial portion 258 and with a radially extending cam 259. Such cam however differs from the stationary cam 59 in the rear hub in that it is supported and carried by the rear hub assembly and hence is rotated in a direction opposite to that of the forward hub, producing a relative rotation between such parts of:v twiceA ther. individual. speed: As a'...result=,;` and.

ixr order:v tosecuref'similar'operation of; thipump. mechanism, cam'A 259-: is: preferably.' formed with" only a single lobe thereon-"soa thatthe same ratev of pump. .operation will be. secured.: iSe'ali'ng means- 7260' and.' 264 provide vfor enclosing.r the interior: of thel reservoir'. at the. adjacent" surfaces'vr of v'Iplate- 250= with' sleeve portion 258:,1 and-1 at theadjacent surfaces:I of'cover 2543'with' sleeve 255; thereby ypre'ventingiescape .off lubricant' therefrom.'

= shafeatr'is1etatauy mountedffwithm1-p1jate 21s and=extends therethrougliewitha pinion'r3zl 8V upon its overh'anginggrendzwhich is'adaptedto mesh with gear `teeth 316. Preferably; three such 'shafts are so positioned in uniformly spaced relation around' the periphery each carrying a pinion in driven relationwith gear teeth3l6, sorasto secure balanced 'operating' conditions.

`Shaft :ill-'basar tongue. andv groove connection.

shown at 319 with a. second shaft 32D'rnounted lwithinrthe ring-.1255, andf extending outwardly Also:A an air'fpressurefreleasing construction simi'- lar to that shown Aat 66, 61 inthe rear hub'is` preferably provided..y

Y The reservoirLwithin' the front hub likewise con'-y tains aipairy off'pumps 271i; arranged in spaced' relation to. eachother; correspondingvalvecham;

ber's21l; and. a single pressure'i'elief mechanism 212, these parts being similar in'construction'and mode of operation tothe correspon'ding'parts y'described abovedny theirear'hulb..y

The regulatorfvalve vbodyI` 3001 of fthe forward'y hub is;slidablymountedwithin cylinder 3M whichi is 'carriedibythe plate-2502": '.Th'e pressureffrom:

the pressure'lzsupply'ysystem .leads'into theacentrall port' 302 'and supplieszpressure tinto. thenareabe tween'- the' two lands '.3031 and:^30.`l.s 'ihesef'laruzisrcontrol loutlets 305l and v3(16 .respectively .and pro"- vider` ferr' establishingv 4communieation from' the pressure `source to. operatingftubesfwfl' and' Staf respectively. In'this 'respect'l the. construction'is.:

- 4blades I6, ring lgear '22| willvbe correspondingly' the'y sameasfpreviously described, fthe.' supplyJo-f pressure uid beingfriselectively:directed:to-:one: I

. lorthe 'other'oftheserpressuresupply lines; to-t'bef i` carriedinte the several blade "soekets. and.A tof. be

there supplied toene "-si'de'orj'th'e otherjofthe: individual. 'pistons in the lbladesockets 'to effect the adjustment 'of the pitchA setting of 'thebladesi` Itwill be understoodfthatf'asfrin .'.theiireari hub;` `iii-troduction'of fluid-1 Dressureithrough: the radially inner 'tube Sllresu'lts inr.bringng' about ade'- creasein thev blade' 'pitchv while :introduction through'outer'ftubelBSY causes yincrease'. in'- the. Ditch oftloesevera'l'blades.A I n i 'i 'l However the control'and 'cperatio'nof` regulator' valvev '300 fini the forwardf'huhare different :from

" withfthe' forwardfhub,

'therethrough'and'terminating in' a threaded portion.32-l withini the reservoir oftheA forward hub. Preferably the shaft` is yprovided with the thrust n collar construction .described'above .in vconnection withzth'e shaft sections I\63-and:|64, providing for taking upaxia-l .thrust ladson the shaftwhile' permitting. readyl separation thereof,Y for dismantling ofthe hub.. Agrooved ringf322i'is 'slid' ably mounted .upon'fsleeve 2 58'y andv threadedlyvy engaged by vthe several'. operating .shafts-32| to' be' moved:-axally. upon rotationthereof;r The ring has azperiphera'l. groove "323 within which* there is adaptedito'. ridev a follower shoes 324' rotatable ingfplacecin the pitch`Y an'gle setting of; the rear rotated; andl this. will ingturn effect the rotation of theA shait'sections.y 32.!` 'to reffect ay corresponding adjustment intheposition of ring. 322 and ofv shoes 3241 Ihus'fori-everypitch' angle `setting of the .rear propeller' blades;` there is'a' corresponding axial positioningof the; shoes 32:4, and they' rejspon'dz` byaxialiimovementzinf one 'direction or the' other to *eitherr increase or'fdecrease' in. the pitch of the rearblacles.'

` Referringz'to' Figs. 1K7v 'an'd 18;. thereis shown the i .ringl gear' 330=which1istmounted .upon rollerlcearing33l for'rotation'. about"forward' hub 25. This vring gear'serves lthesame-.purpose as previously ldescribed gear-22| lin' the'r realrhub;` in synchroof-Y being `independently f controlled: 'in zresponseato'.

speed or manu'alwad-justment; the'iregulating ac-l tionv of valve 30.0'is made dependent `upon'changes` inthe actual settingo'fItheblades ofthe rear hub; By'providingfanfelenrent Within the forward hubow-hich y.isi' adjustabler inqiaccorda-nce with, ory itri'esponsetochanges ini, thefsettinggof.the'blades'.Y of.v the rear: hub: theA forward. regulator 'valve is' displacedfr'omr its 'neutralirpcsition 'and made to; respond' to such. changes rin'ithel rear blades,.there by,r controlling' theI setting; 'of' the forward blades' impredetermined: relationr. with respect'sthereto.'y

Arfollovw upgmechanismisl provided so= that 'whena' the proper adjustment" has. taken place in'th'ejfor'- nizing' or correlating theadjusting'movements ofl the several blades in the forwardI hub, each bladey having a sector meshing'iwith. the' vring-"gear and making it necessary'that'all'of such blades'occupy the'- sameangular position. at all times. The bear'- ing' 33| isfretainedi'in place by means of a h'ousshown.. at `33?, andA4 with a. locking ring 334 threadt edffi'nto'fthe: hubi 25for"re'tainin'githe same in' po- Asition'. p A In order'to providefa' follow-up device respon-v siye'r: toI the" change' nin: position of "the forward b'la'rie'sithe ring'gear 330 is provided with a forwardlyf'extending sleevexpjortion 340. which is Ward; blades' to= correspond lwith the change rwhich:v

has occurred.v in'- .the' :rear: blades, the regulator, valvewill. bef restored tov :neutral position', cutting 01T .supply ofzregulatin'ga'ilnidto. either side'-'of the?.

pistons.V Although thefyalvermay-be arrangedl'in a: radialvpositionzfor ypurposes of simplification. and standardizatiorrof.l parts'fin'jthe two hubs and isi .thus subject to centrifugal. force; that force is not 'utilized in.' the-control of-its operation, Aits position. beinggdetermined inspthefy manner described regardlessof the centrifugal-force'acting' thereon. For s this. purpose; sting; gear 1i 2 2 I 'fini the rear 'hubis provided' withfa forwardlyl extending'v n cylindrical part 3.-l'5 fuponirthe-internal face ofy which fare provided a:series-Sofi.gear.` teeth 3 I6. A1'

throatfof the bladesockets,l and out 'of'that areaA occupied' bygthef previously, described operating recessed as vshown at 34| to provide for' receiving camp'lates. 342' therein.' `T'hefcarn plates are l0- .c'atedi in spaced' relation. around 'the periphery of? .sleevev 34'fand .'inr'symmetrical relation at either.

side-of one;ofr.i1the blade sockets.` These cam platesf are removably heldwithin' the sleeve rec'esses1334l .lbyimeansrof'sb'olts 343so\'that if deelsi'red' each: onezcanifbezreadily' removed'. and: re-

l placed Acamz'sloti344 of. predetermined shape' is.4 provided withinztthefplates 342,' and working within each such slotv is a camnger 345( Fingers 345may be-"formed' as an' integral .part of 'operating rrods .346'which' pass'fthrou'ghfrthe lower' walls at'eithersidof one'of the blade `sockets 26'being' guided thereby'vfor axial movement; the operating` rods: extending: rearwardly in't'the'zone of the the.' ring itself being "rotatable with'the rearl'iu'b'.' f It will bezclearthat'upon: anyadjustment tak.-

and adjusting mechanism. The direction of the cam tracks 344 is such that upon increase of blade pitch, rods 346 are moved forwardly or toward the forward end of the propeller, and vice versa. l

Rods 346 extend through plate 250 and into the reservoir where they terminate in ball and socket joints 355. Connection is there made to floating levers 35| which extend downwardly past the opposite sides of ring 322 and are attached to the shoes 324. The two levers 35| are preferably joined together in an arcuate manner at theirA lower side, and connection is there made to a lug 35? having an elongated slot 353 therein. A bell crank lever 355 is pivotally mounted at 355 and carries pin 351 at one end which is adapted to ride within the slot 353. At its other end, the lever is formed with a bifurcated part 358 which engages over pin 359, carried by the valve body 3D0. Thus upon pivotal movement, of the bell crank lever in one direction or the other away from its neutral position, the valve body is caused to move inwardly or outwardly to provide for supply of pressure from the pressure source to the individual blade pistons for effecting selective adjustment in the setting of the blades to effect increase or decrease of the pitch thereof.

In operation, upon a change taking place in the setting of -the blades in the rear hub, a corresponding shift in the position of ring 322 takes place as described. Assuming an increase in the pitch of the rear blades to have taken place, ring 322 is moved axially toward the plate 250, i. e., toward the left as shown in Fig. 17 With rods 345 stationary, the shoes 324 move toward the forlward blade sockets and lever arms 35| pivot about the point 35|), causing a displacement of lug 352 and a corresponding rocking of bell crank lever 355. This movement displaces valve body 30D from its neutral position, causing it to move outwardly and supplying pressure fluid through line 339 and into theseveral blade pistons in the direction to cause increase of the pitch of the blades. As adjusting movement of the blades in the forward hub takes place, ring Igear 330 is caused to rotate, and the cam track 344 thus causes a displacement of rods 346 to take place to the left as shown in Fig. 17, this displacement being in such direction as to shift the pivot points 353 in the same direction as the shift imparted to ring 32|. The supply of pressure fluid to the blades in the forward hub continues therefore until such time as, with continued rotation of the blades toward increased pitch position, the

pivots 35|) have traveled toward plate 250 to a position in which levers 35| have returned the lug 352 to its original position. This occurs when the extent of movement of rods 346 bears the same ratio to the entire length of levers 35| that the extent of movement imparted to ring 322 and shoes 324 bears to the length of the portion of the levers inwardly of the shoes. When such conditions have been reached, valve body 300 is ren turned to neutral, and adjusting movement of the forward blades ceases. It will be clear that the cam 342 is made of proper shape and such as to produce the necessary extent of movement of pivots 35|). Further where the lead of` the cam is uniform, the forward blades will follow in their mo-vement the adjustments which occur in the rear blades assuming the same pitch positions throughout the entire range. In some cases it is found preferable to have a differential adjustment take place, with the pitch of the forward greater or less degree than that of the rear blades. In such case the cam track is suitably shaped to provide whatever relation is desired between the two sets of blades throughout the entire range of adjustment thereof. For example the pitch of the forward blades may be made to vary from that of the rear blades bya constant amount, such as a few degrees, or by a ratio, providing a greater diierential at higher blade angles. The accessibility andreplaceability of the cam plate facilitates making changes in such condition as desired.

The reverse operations of 'course take place upon adjustment of the rearl blade in the opposite direction, there being vcorresponding balance Ipoints for the follow-up rods 346 forl every setting of ring 322 at which the valve body is restored to a neutral position. n

In actual operation, these adjusting movements occur quite rapidly so that the forward blades begin to operate shortly after movement of the rear blades has begun. As soon as the valve body has been displaced from its neutral position, control iiud is supplied to the forward blades in such direction as to bring about a corresponding change, and movement thereof follows immediately. In the case of an extensive adjustment of the rear blades, the movement of the forward blades takes place concurrently and with only a brief lag with respect thereto. Actual movement of the bell crank lever andthe valve body therefore is relatively small, being merely enough in one direction or the other from neutral position to uncover and establish selective communication with the proper pressure supply tube.

It will be apparent from the foregoing that the forward blade adjusting mechanism will operate to maintain the blades at the predetermined pitch position corresponding to the particular setting of the rear blades. Thus assuming a change in the setting of the` forward blades, for example, by reason of reduction of fluid pressure within the blade pistons, and under such operating conditions that the forces effective upon the blades would cause a reduction in the pitch thereof, such movement would rotate ring gear 330 and cause corresponding shifting of rods 346. If the change was a decrease in pitch, rods 346 would move toward the rear hub', and would pivot about shoes 324, resultingjn movement of bell crank 355 and outwardly displacing valve -body 30|). This movement effects introduction of pressure fluid in the direction to cause increased pitch'bf the blades, thus correcting for the change which presumptively occurred, the supply of fluid continuing until the pitch of the blades has been restored to its predetermined value. Analysis will show that a similar corrective action occurs upon a change in the opposite direction, the systme thus effecting initial adjustment of the forward blades to a predetermined 'pitch position corresponding to each pitch setting of the rear blades, and then providing for maintaining the forward blades in such predetermined position.

The principle of this control f. has been illusvtrated diagrammaticallyv in Figs. 21 through 24 in greatly simplified form in order to more clearly show the functioning and operation thereof.

In this arrangement, the engine is indicated at' a, the drive shaft for the rear hub at bl and for the forward hub at bb. The rear blade socket and hub are represented at c, including all of the elements within the rectangular outline which are rotatable therewith. -Similarly the forwardv hub, 'blade socket and parts rotatable therewith point zz with the valve body.

are ,shown r`within the left 'hand orfQrWard .IGC-i The. manual -or instrument-controlledfadjust# ing vmechanism is shownatd, effecting adjustmentin the position of the slidable ringe through the toothed sector, ring gear, pinions,- and threadtangle,` the blade'. socket being marked cc.-

ed shafts as shown.v Pivotally mounted lever fl rotatable ywith the hub carries .a shoeiwhich VVruns in', ring e, and is rocked v`therebyto'clfiangejtlle position; of fulcrurn roller g at its opposite-end,A Movement of roller g changesg'the eiectivevfforce Vof spring hwhich isppposed tothe centrifugal force acting on regulator valve body i,4 n Fluid pressure is developedvby'puvmpf-zj, rotatable with the hub and actuated byr contactwith non-rotatingcam 1c, and is supplied-to 1;lo efregllv later valve, i.r

ncause pitch adjusting movement; of the indirv vidual blade-upon travel of the pistoni.;l -With tends to constantly assume a position .wheresucn forces; are in balance, being displacedfrom that position upon a departure of ther-speed of rota-v tion of ythe propeller lfrom the predetermined value, and upon vsuch displacement ,causinga changein the pitch or lthe blades :intheproper sensato .restore such speed condition. Upon/tad,-

Valve'i controls-the application y of suchfpressure to one side ortheotherwof the blade adjusting piston Z-withingbladesocket An abutmentm and splinel connection vshovvn-.at e

- maar l '11n Fia 23, as a result yof, an adjustment move,- ment having taken place inthe rear hub`, ring ee has moved and the shoe ov is jno` longer in its original position but has moved to a nevv position l v'v. Prior to-'movem'ent of the forward blades',

follow-up rod ss has not moved,'and hence point it has not moved. Leverl uul is therefore caused to pivot about point tft thereby causing theend ww of y -thebellcrank to Inoveltoea position wwf ..Whichfin turn has moved the point eatoneW-positionz'e. I

This ,results in displacement ofthev valvefbody; f

causing .the supply lof* pressurevv fluid te Ione side ofthe-.piston ZZ; ,"Asth'efpiston' moves in response'to thatA pressure application, thefollovvrup -rod-ssislilrewise eausdto move, and continues to moVewpOint ttv tornew position tt'.. When it reaches such positiontt,l`(shoe' vv Aremaining at ov') the lever uu is swungftorbring point vww 4lever d inany fixed position, thecentrifugalfforce acting upon valve body i is opposedby anionstantv moment of force produced by spring blandv hence back to the original Vww position;A thus restoring the bell. crank :m: to its original or yneutralposi-r tion.` With vthe bell crankjthus restoredlto .its original pos'ition,.point aa has beeny restored, and thevfalve bodyhas been returned toits neutral position Where j further v supply kof pressure fluid is cut offl- The'pitch vof the forward blades lis y thus maintained at all times'in l'close'correlation Withthat ofy theel-rear blades.

V It is believedthat ,this win'nake naar the' rmanner of operation tof; the device", it being clear that upon an opposite movement of the blades withinthe rear hub, the oppositesequence of .op-l

Y erations takes place inthe forward hub,.the posi;

justment of lever 1d, l,the effectofthe spring `force l ischanged, and-thus. a new Speedfconditipn is selected `at which the centrifugal, forceonf-the valvefbody `will kbe inbalancer-With the" applied spring force, the valve being displaced from neui tral to'produce'such change inbladelpitchffas l will bring about suchspeed change.

, AThe ring gear` o 'correlates theaction 4,o e rear blades through'beveled gear sectors p carried thereby` and ,provides for ladjusting the position of ring ee in the forward hub in. accordancevvith the setting of the blades in the rear-hubA through i the provision of fthe, internal teethlonrinug gear.

0,' pinions and threaded shafts,asf shown5.-

' Pressure is developedin'thefgryvard hubby pump. means 7'7" rotatable with thefforward hub Y and. operating against cam kk carriedbythe rear hub and hence rotating in the .opposite direction.

Suchpressure is supplied tov'alve'nii*from which it-fmay be applied to the adjusting piston -lZ in the forward blade socketl ccunder thecontrol.of

the valve. The abutment mm clauses movement of; pistonjllrto effect twisting of the blades k,in-the` forwardy hub, through spline `connection there slidably operatesfollowujp redes.: yllt terminates at point tt, Wherel it is connectedftothe upper end of ythe leveru-u, to which is connected atan intermediate point the shoes' vowhichride Within` the ring ec. At its lower end,the point ww, the leveris connected to bell crankmz piuotally mounted atv .yy and lhaving connection at Fig. 22v .is a diagrammatic .represenaticn y.of a

tion ofthe blades of vthe forward hubthus being made to followv and bedependent upon those'of the rearhub. Asdescribedabove', the pitch angle l settings ofthe forward blades may bemadelto follow and ,correspond precisely withthosefoflthe i rear blade,for toincrease ordecreasernore rapidly than-those'. of the rear hub where a differential isdened in the lappended claims.v

V,lftinggear oo actuated by sectors pp rotatable -r with the blades is provided with acam plategq' having a cam groove rrtherein within which 4 .1; dual rotation 'propeller of the. character described'adapted to' be driven yfrom a pair of oppositelyrotating drive shafts comprising va pair of hubs respectively .associatedin driven relation with vsaid drive shafts and each provided With, a plurality of I .blade sockets, .propellerfblades ad,- justably mounted inl eachof said sockets, the blades of onehubbeing lof opposite pitch to those vof the otherhubgfluid pressure actuating means in each of said sockets for eiecting adjustment f of said blades to var ythe: pitch thereof, separate normal or balanced po'sitionof` thevpartsl` yy-n this position lever uu lis in 'alignment with the'` one v arm orfbell crank lever ma: and henoelthe bell crank occupies its neutralpositiomand-through connection zz causesvalve ii to occupy tsineutral position lin which :no nuid is supplied 1 -tol either side of lvthe operating piston-ll; j

fluid pressuredeveloping means in each vhub 'to supply-fluid ,under pressure vto said actuating means Vvvithin that hub, and means within each hub for controlling the application of the fluid pressurev to the associated actuating meanslto effect adjustment of the pitehse'tting` of the blades thereof the eontrfolling meansy Within onehub actingin response to changes in actuallsettinglfy theA blades ofthe other hub. i

2. A dual vrotation Propeller of `the y character described adapted tobe drivenfrom a pair ofi-op,-

placedftofs'ecure variation inthe operating conf v departing from the scopeof the invention' which positelyrotating drive shafts comprising a pair.

of hubs respectively associated in driven relation with said drive shafts and each provided with a plurality of blade sockets, propeller blades adjustably mounted in each of said sockets, the blades of one hub being of opposite pitch to those of the other hub,'fluid pressure actuating means in each of said sockets for effecting adjustment of said blades to vary the pitch thereof, separate liuid pressure developing means in each hub to supply fluid under pressure`to said actuating means within thathub, means Within each hub for ycontrolling the application of the fluid pressure to the associated actuating means to effect othersad hub dependent upon the position of the blades in said first mentioned hub for controlling the application of the vpower developing means of said other-hub to the power actuated means thereof to' effect va corresponding change in the i pitch setting of the blades of said other hub.

blades of one hub being of opposite pitch to those means within that hub, means within each hub for controlling the application of the uid pressure to the associated actuating means to effect adjustment of the pitch setting of the blades thereof, speed responsive means in one of said hubs for regulating the controlling means in that hub to ,adjust thesetting of its said blades to maintain Ya constant .speed condition, andmeans in the other of said hubs for effecting a corresponding adjustment in the regulation of its said controlling means.

4. A dual rotation propeller hub adapted to be driven from 'a pair of oppositely rotating drive shafts comprising a pair of hubs each associated in driven relation with one cf said drive shafts and having a plurality of blade sockets for adjustably receiving blades therein with the blades of one hubbeing of opposite pitch to those of the other, power actuated means in each hub for adjusting the pitch of the blades thereof, means in each hub for developing power to effect actuation of said power actuated means, and control means inr each hub for controlling the application of said developed power to maintain a predeter-K` mined position of said blades, and means for correlating the action of the control means in said two hubs to cause both'sets of blades to occupy a corresponding pitch position to each other.l

5. A dual rotation propeller adapted to' be driven from a pair of oppositelyrotating drive shafts comprising a pair of hubs each associated in driven relation with one of said drivevshafts and having a plurality of blade sockets, blades adjustably mounted in said blade sockets with those of one hub being of opposite pitch to those of the other, power actuated means in each hub for adjusting thepitch of the blades, means in each hub` for developing powerlto effect actuation of said `power actuated means, independent control means in one of said hubs for controlling the applicationof the power developing means thereof to the power actuated means thereof to effect adjustment of the pitch setting of the blades of that hub, and control means in the 6. A dual rotation propeller adapted to be driven from a ypairof oppositely rotating'v drive shafts comprising a pair of hubs each associated in driven vrelation with one4 of said drive shafts and having a plurality of blade sockets, blades adjustably mounted .in saidblade sockets with those of one hub being of opposite pitch to those of theother, power actuated means in each hub for adjusting the pitch of the blades thereof, means' in eachhub for developing power to effect actuation of said power actuated means, speed responsive means for controlling the application of power developed in one of said hubs to adjust the position ofthe blades of that hub to maintain a predetermined speed condition, and control means associated with said other lhub for controlling the applicationl of power'developedin said other hub-to cause the blades of the latter hub to assume a 'position corresponding with those of the first mentioned hub to maintain a constant speed and balanced thrust condition of the entire propeller.

7. A dual 4rotation propeller adapted to be driven from a pairof oppositely rotating drive shafts comprising a pair of hubs each associated in driven relation with one of said drive shafts and having a plurality of blade sockets, blades adjustably ymount'edin said blade sockets with those of one hub being of opposite pitch to those of the other, fiuid pressure actuated means in each hub for adjusting vthe pitch of the blades thereof, a source of fluid pressure in each hub for application to said ypressure actuated means to effect adjustment of the pitch of the blades, speed responsive means within one of said hubs for controlling'the application of said pressure source to adjust the position of the `blades of that hub to maintain a predetermined speed condition, and control means associated with the other said hub andresponsive to the position of the blades in said first-mentioned hub for controlling the application of the; pressure source of said other hub to the pressure actuated means thereof to cause the blades thereof to assume a position corresponding with those of said first-mentioned hub.

y8. `A dual rotation propeller adapted to be drivenfrom a lpairof oppositely rotating drive shafts comprising a pair of hubs each associated in driven relation with one of said drive shafts and having a plurality of blade sockets, blades adjustably mounted in said'blade sockets with those of one hub beingvof opposite pitch to those of the other, fluidpressure actuated means in each hub for adjusting the pitch of the blades thereof, aA source of fluid pressure in each hub for a-pplicationfto said pressure actuated means to effect adjustment of the pitch of the blades, speed responsivev means within one of said hubs for controlling the application of said pressure source to adjust the position ofthe blades of that hub to maintain a predeterminedspeed condition, independent control means associated with said one hub for adjusting said speed responsive means to vselectively vary said predetermined speed to which said propeller is regulated, and control means associated with the other said hub and responsive tothe position of the blades in said first-mentioned" hub for controlling the application of the pressure source of said other agsemcu hub. mmepressure .actuated means. thereof; te 1 cause the blades thereof to .assume a position corresponding witlrthose of said mst-mentioned v hub. 1

thosey of` cnehub: being off opposite pitch to those ofthe other, fluid pressureactuated meansin eachhub forl positively adjusting*y the Apitchof the blades thereof in both pitch increasing and decreasing adjustments, meansin eachhub for de' veloping fluid pressureto effect actuation of said passingV the `fluid pressure actuated meanspindependent control means in one of said hubs for controlling they application of said fluid pressure to said pressure actuated means tov adjust .the blades of said hub to a-predeter'mined pitch position, means inthe otherrsaid 'huby dependent upon the actual position of the blades oi"` said 'rst mentioned hub for i l rotatable With each ofrsaid hubs, pump mechay nismfca'rried by each hub and communicating with -saidfrespective reservoirs, a stationary memcontrolling the application .of the iiuid pressure within said other hub to the pressure actuated means thereof tomaintain a corresponding posi-` i hubl `to vary by aY predetermined-differential from lthe pitch setting tioned hub. y

1 10. A dual rotation propeller adaptedVto"bev driven' froml a pair of ioppositelyfrotating"drive shafts comprising a pair of hubs each associated "2'.

with forireceiving a quantity-of operating iluid` therein, means within. each reservoir [for fsubjecting the fluid therein to pressure to provide independent sources'of pressure actuating fluid,A

fluid pressure actuated means in veach blade socket Vfor effecting/adjustment ofthe pitchl setting vof the blades therein, control meansin each hub for separately controlling "the application ofr the fluid pressure sources thereof to said' pressure tion ofthe blades of that hub'in relation tothose yof said first mentioned hub, andy meansv for caus' Y ing the pitch setting of the bladesoi said other ofl those' of said first' men- 1 misnomer ,the -prepeuerfer. subjecting-.th 're'- spective bodies ofv fluid topressure,-pressure rev vceiving meansfor receiving the fluidv discharged from seidl'pump means, rand means for Vlimiting the action yofsaid pump, means upon theestablishxnent of. a predetermined pressure condition" within said receiving means including valve members subject to centrifugal force upon rotation of saidhubs,v means for supplying` fluid pressure from said receiving means to said valve. means to move said valvesagainst they action of centrifugal force -whenthe pressure in said receiving. means reaches said predetermined amount, and a ybye-pass.. associated 'with each said pump means 'and'.openedby movement of said valve .for by# ,fromxsaid pump back to said reservoir. e l y 12. Aadualrotatlon propeller ofthe character described comprising'a'p'air of drive shafts rotate? ing` in opposite directions, hubs positioned ron each drive shaftin tandem relation to each other,

a.. plurality". of -hydraulically adjustable blades y carried' byf each'hub, a fluid-containing reservoir b'er operable uponfthe pump ,mechanismV offth'e rearxhub to provide for actuation thereof to sub- Aject'the kiluid in the reservoir ofthe rear hub f;- to`pressure,.a member carried by the` rear hub .and operable `upon the pump mechanism fof the forward hub to provide for actuation thereof to subject: the iluid'in thereservoir of the forward hub .to pressure, means Within each hub' for lcon#- trolling theapplicationjof fluid vpressure to the respective hydraulically adjustable A blades, and

:neansresponding to the changes in actual set'- 'v ting @fk-the' @blades ef yene hub fory initiating change in the controlling means for the other hubft'oeifect va llikey change of blade setting.

1f13; A d uai 'rotation prepener of 'the character i 'described' whichcomprises a pair of hubs adapted to be received intandem Yrelation upon oppositely rotating drive shafts, adjustable pitchy blades actuated means, speedresponsivemeans in one of said hubs for regula-tingr vthe operation'of the .i

associated controlmeans therein,y and means in the other of said hu'bsand responsive to the actual setting" ofthe blades in lsaid lfirst-men;`

tioned hubfor regulating the'action of its said associatedcontrol means to thereby eiiectfa Acor-- responding pitch settingof the bladesv of both oi said hubs. e l. 11. A dual rotation propeller hub :mechanism of the character described comprising a pair of adjustably rsupport thefpropeller blades therein;r` vseparatev fluid pressure distributing means withinr each hub for effecting adjustment of the pitchof the/blades of that hub,'.liousings carried byV eachy hub 'and forming `separate vreservoirs `therew1th for receiving a body'of pressure :actuating fluid, means extending fromjone housing into' the other thousing for transmitting the adjusting vof pitch.

mountedupon said'y respective*` hubs, iluidpres; "surefresponsive'means fori effecting pitch adjust- Ument of said blades'uid pressure means for sup.

'p'lyi-ng fluidunderpressurel toI effect. actuation of `lsa'i'd pressure" responsive means, independent control means for oneof said hubs for controlling fthe-'supply loi pressure uid toa'djust the pitch y fof'tnegblades "orti-iat hub te a predetermined position,- andjcontr'ol'nieans for the other "said eo i described yvvliichy comprisesvv a pair of "hubs .adapted 'meansifor synchronizing the adjustingfoperation `ofthe .blades offene hubfwith the blades'fof "the .other'hub, iluidpressure means for supplying 7'0.

ofsaildf'rst'hubfor,controlling 'the supplyof pressureffluidjto adjust-theA pitch of the 'blades' 'ofgfsaid `other hub in substantially synchronized relation with the pitch Aof the blades of said `rst 'mentionedhub.l f Y.

14. A dujai rotation prepeuer ef; .the character to be received in `vtandem relation lupon oppo-L sitely rota-ting',f drive v`4shafts; adjustable jpitch bladesniounted @upon saidfrespectivehubs, iluid .pressurerespon'sive means associated with leach blade kfor 'efreetingpiteh' adjustment thereof;

fluid',-.under` pressure to veffect actuation oi' `ysaid pressure 'responsive means, independent control n ieans-forfone! of said hubs for controlling 'the `of'blades lof one hubto the iluid'pressure Ydis-y tributin'g means of the ether-hub; means within e each hub including `pump means operable upon supply of. pressure viiuidto adjust the pitchk of the bladeseof that hub 'to a predetermined posi- `tiornsmeans#for initatinigthe supply ofl'pressuw `1 uid tov the `pressure responsive means ofvsaid other hub in accordance with a change in the setting ofthe blades of said rst mentioned hub, and means for terminating said supply of pressure` fluid to the pressure responsive means of said Iother hub when the blades of said other hub have been adjusted to a position corresponding with. that `of said first mentioned hub. f

15. `A dual rotation propeller of the character described adapted to be drivenfrom oppositely rotating drive shafts comprising a pair of hubs adapted to be mounted in tandem `relation upon said drive shafts and each provided with a plurality of blade sockets, propeller blades adjustably mounted in` each of said sockets, the blades of one hub being.4 of opposite pitch to those of the other hub, fluid pressure actuating means in each of said socketsfor effectingadjustment of 'said bladesv to vary the pitch thereof,'separate just the setting of its said blades to maintain a constant speed condition, and means in the other of said hubs for effecting actuation of Said` control means in said other hub away from its neutral position upon change of pitch of theblades of said first mentioned hub, and follow-up means responsive to the change of pitch of the blades of said other hub to a position corresponding to that'of theblades of said rst mentioned hub for restoring said control means in said other hub toits neutral position.

16. A dual rotation propeller of the character `described adapted to be drivenfrom oppositely rotating drivefshafts comprising a pair of hubs adapted to be mounted in tandem relation upon said drive shafts and each provided witha plurality of blade sockets, propeller blades adjustably mounted in each of said sockets, the blades of -one hub being of opposite pitch to those of the `other hub, iiuid pressure actuating means ineach of said sockets for effecting positive adjusting movement of said blades in each direction to vary the pitch thereof, separate fluid pressure developing means in each hub `to supply fluid under pressure selectively to said actuating means within that hub for effecting pitchincrease or decrease, control means within each hub adjustablevin each direction away fromv a neutral position for controlling the application lof the 4fluid pressure to the associated actuating means to effect adjustment of the pitch setting Oftheblades thereonspeedresponsive means in one of said hubs for regulating the controlling means in that Ihub to adjust the setting of its forrestoring' the said displaced `vcontrol means to neutral position when thev blades of said other hubhaVe been changed in the same sense and to acorresponding position.

17. vA dual rotation propeller of the character rotating drive shafts comprisingga'palr of hubs adapted to be mounted in tandem relation upon said drive shafts and eachprovided with a plurality of blade sockets, propeller blades adjustan pressure to the associatedI actuating means to effect 'adjustmentr of the pitch setting of the blades thereof, speed responsive'means in one of said hubs for regulating-the controlling means in that hub to adjust the setting of its said blades to maintain a constant speed'condition, means in the other 'of said hubs responsive to a change of position'of the bladesofsaid first mentioned hub for effecting displacement vof the control means of said other hub' away from its neutral position in a sense corresponding to the direction ofsaid change ofl position, means for restoring the `said displaced control means to neutral position when the bladesof said other hub have been n changed in the same sense and to a corresponda ing position and removable and replaceable means associated with the control' means ofsaid other l described adapted lto be driven from :oppositely 76 hub for predetermining the relative settings between said bladesin corresponding positions.

18. A dual rotation propeller of the character l described adapted to be driven'from oppositely rotating .drive shafts "comprising a, pair of hubs adapted to be mounted in tandem relation upon lsaid drive shafts, propeller blades adjustably carried by each of `said hubs, the blades of one hub b'einglof opposite pitch to those of the other hub, fluid pressure actuatingmeans in each of said hubs for effecting adjustment of said blades to f vary thepitch thereof, separate fluid pressure developing means in each hub to supply fluid under pressure to said actuating means within that hub, means within each hub for controlling 'the application of-the fluid pressure to the actuating means of that hub to effect adjustment 'of the pitch setting of the blades thereof, independent means in one of said hubs for regulating the controlling means of .that hubto adjust the setting ofits said blades to a predetermined position, a member in said other hub responsive to the position of the blades of said first mentioned hub, a second member in said other hub responsive to the positionl of the blades of that hub, and

. means responsive to the position of said two members for regulating the Vaction of the controlling means of said `other hub to'provide for maintain? ing a predetermined relation between the setting of the blades of said two hubs.l i j 1'9. A dual rotation lpropeller of the character described adapted to Abe driven from oppositely rotating drive shafts comprising a pair of hubs adapted to be mounted in tandem relation upon said drive shafts, propeller blades adjustably carried byeach of said hubs, the blades of one hub being of opposite pitch to those of the other hub, duid pressure actuating means in each of said hubs for effecting adjustment of-said blades to vary the pitch thereof, separate fluid pressure developing ymeans inr each hub to supply fluid under pressure tofsaid actuating means within that hub,

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