US2501432A - Propeller pitch adjusting device - Google Patents

Description

March 21, 1950 BQQTH 2,501,432

PROPELLER PITCH ADJUSTING DEVICE Filed Dec. 18, 1944 4 Sheets-Sheet 1 up ZNVENZUE James H B 00th March 21, 1950 J. H. BOOTH 2,501,432

PROPELLER PITCH ADJUSTING DEVICE Filed Dec. 18, 1944 4 Sheets-Sheet 2 Jame; H1300 Zfh ZZ/WWW Mangh 2N1 }950 J. H. BOOTH 2,501,432

PROPELLER PITCH 'ADJUSTING DEVICE Filed Dec. 18, 1944 4 Sheets-Sheet-4 Patented Mar. 21, 1950 PROPELLER PITCH ADJUSTING DEVICE.

James H. Booth, Detroit, Mich., assignor to Thompson Products, Inc., Cleveland, Ohio, a

corporation of Ohio Application December 18, 1944, Serial No. 568,605

2 Claims.

This invention relates to an inexpensive device for adjusting members, such as blades, and specifically relates to an easily installed propeller pitch adjusting device.

The invention provides a small compact assembly, rotatable with a propeller hub, for changing the pitch of propeller blades that are rotatably mounted in the hub. The assembly includes fluid pressure-operated means acting on the blades to rotate them in their mountings. Fluid pressure for actuating these means is created by a pump. The pump is actuated by a non-rotatable cam, and this cam is manually actuated by the pilot into and out of pump-operating position. i

According to this invention, the blades of a propeller are mounted for rotation in a propeller hub in such a manner that the aerodynamic force on the blades in operation tends to move them into high pitch. The device of this invention is contained in the hub of the propeller and, when the cam is moved into position for actuating the pump of the device which rotates with the propeller hub, the hydraulic pressure generated by the pump will move the blades into low pitch against this aero-dynamic force.

In order to cause the aero-dynamic forces on the operating blades to urge the blades into high pitch, the blades are tilted back from their radial rotating axes to move their centers of gravity toward their centers of radial rotation to lessen or negative the centrifugal torsion eiiect tending to rotate the blade into low pitch and the blades are designed to have their centers of pressure to the front of the centers of radial rotation.

While aero-dynamic force alone can be relied upon to urge the blades into high pitch, it should be understood that this force can be augmented by springs, weights, or the like.

A feature of this invention resides in the provision of a compact hydraulic pressure-operated propeller pitch-changing device that can be readily installed on standard airplane engine mountings.

Another feature of the invention resides in the provision of a self-contained unit in a propeller hub for changing the pitchof blades rotatably mounted in the hub.

Another object of this invention is to provide a hydraulically-operated propeller pitch changer utilizing only minute quantities of oil or other hydraulic fluid.

v A further object of the invention is to provide a device which adjusts the positions of rotating blades in accordance with the manually adjusted position of a non-rotatable member.

A still further object of the invention is to provide a propeller pitch-adjusting device wherein a stationary cam actuates a pump for producing pressure to change the pitch of propeller blades.

A still further object of the invention is to provide a propeller pitch-changing device embodying a cam member actuated into and out of operating position by the pilot of the plane and, when in operating position, causing a pump rotatable with the propeller to produce hydraulic pressures for overcoming aero-dynamic forces on the propeller blades to change the pitch of the blades.

Another object of this invention is to provide a propeller pitch-changing device having a pump actuated by a cam and a fluid flow control valve actuated by another cam to operate plungers for moving propeller blades about their radial axes.

Other and further objects of the invention will be apparent to those skilled in the art from the following detailed description of the annexed sheets of drawings which, by way of preferred example, illustrates one embodiment of the invention.

On the drawings:

Figure l is a plan view of a propeller mounting according to this invention embodying a propeller pitch changing device according to this invention.

Figure 2 is a front end elevational view of the mounting shown in Figure 1 with parts of the propeller blades omitted.

Figure 3 is a cross-sectional view taken along the line III-III of Figure 1.

Figure 4 is a cross-sectional view taken along the line IV--IV of Figure 1.

Figure 5 is a cross-sectional view taken along the line V-V of Figure 2.

Figure 6 is a cross-sectional view taken along the line VI-VI of Figure 5.

Figure '7 is a cross-sectional view taken along the line VII-VII of Figure 4.

Figure 8 is a plan view taken along the line VIII-VIII of Figure 7.

Figure 9 is a cross-sectional view taken along the line IX-IX of Figure 8.

Figure 10 is a cross-sectional view taken along the line XX of Figure 8.

Figure 11 is a cross-sectional view taken along the line XIXI of Figure 8.

Figure 12 is a fragmentary crosssectional view taken along the line XIIXII of Figure 13.

Figure 13 is a plan view of the ring block taken along the line XIII-XIII of Figure 5.

Figure 14 is a plan view of the cover plate for the ring block taken along the line XIV-XIV of Figure 5.

Figure 15 is a developed diagrammatic view illustrating the operation of the fluid pressure actuated parts of the device of this invention.

As shown on the drawings:

As best shown in Figures 1 and 5, the device of this invention includes a mounting plate II] for operatively attaching certain parts of the device to an airplane engine I I. The engine H has upper and lower boss portions Ha. Brackets l2,

I 82 carried by the mounting plate It straddle each boss portion lid and a connecting pin or lug l3 secures the brackets to the bosses. The'ni'ount ing plate I!) has a cylindrical collar portion ill projecting forwardly from the front end of the engine ll and this collar portion vIlla slidably receives a control member Mhaving a cylindrical side wall in engagement with the -collar portion Illa and equipped with several sloping slots H5 at spaced intervals therearound as best shown in Figures 3 and 7. These slotsv 15 receive theheads 16a of bolts 16 which are passed through thickened portions of the collar Illa and secured to the collar by means of nuts I! as best shown in Figure .3. r

The collar lll'a-h'as an elongated slot lob there" in and an arm 'l-B secured on the control member l4 extends through the "slot lilb to receive a clevis l9 on the end of a control rod, an operating Bowden wire or the like 20. The control rod 2t passes through an aperture in the mounting plate lilo, as'shown in FigureS, and is directed to the'cock'pit or the airplane where it cah'be easily reached for manual actuation by the pilot. Movemerit of 'the control rod!!! will swing the arm 18 to rotate the control member i l in the collar portion lfld. However, since the heads ltd proj'ect into the ungousisiot ihof the control member 14, any ro'tati'onfoi the "control member will slide it axially relative to'jth'e collar the.

mounted about longitudinal or radialaxes such 'of the blades; As explained above, each blade is 7 so tilted with respect to its axis of radial rotation The control member an'end face with 'a cam track Hid tliereo'n'ali'd "a flat surface Mb surrounding the cam track Ma.

As shown in Figures 1, 5 aridj'ka propeller hub casing 2i ha'sfa rear end portion freelye'mbracare the sonar portion i-toot the i nounting i la"te ill. This casing 21 has 'dialhetri'cally opposed laterally projecting cylindrical socket or sleeve portions f2la which receive the inner ends ofpropeller'blades B. V p

The hub casing 2!, as best shown in Figure 5 has a back wall 2'! b 's'paeedin' front of the'i'nountingplate H] and extending radially inward'tjo a central hoss Or hub portion zicjwhi h is mounted on the engine shaft S; proi from the front end ofengin'e ii. The ehgl-n'e shaft s is prererably tapered to receive th'e'hub portion 'fiic in Wedgin'g r'elatioh'shib ahd keyiheahs 'suchfas K (Figure 4) connect the 'shaft'and hub portion tic for corotat'ion.

A nut 22 is threaded the front nd offl ne shaft'S to thrust'a'gainstthetno of the "portion Ho and hold it on the shaft. Thisnut is locked ag'a'ihst rotation by means ofjpins such as anchored in the nut and "hollow'skirt-like end S of the shaft.

A streamlined nose casing 24 is secured onfthe front end or the hub'casing 2Tby means of screws 25 or the like for coveiihg'th'e open front of the S 'Z- A s o. I v t The blades 13 have their inner ends secured'in tapered "skirt portions 25 6a or retaiiier members 26 which are rotatably mounted on ball bearings"?! in the'soeket no or the hub'c'as'i'ng. Nutses threadedbn the socket's il a thrust against the outer race rings of the ballbearings 2'1 to retain these outer raceriires in the socket. The ball 'df the bearings retain the i'nlfle'r race rings in position all'd a 'lo'ckihg' ring 29 retained in groove of the retaine'r'h-l'e'inberlfi thrusts against an inner-race ring of one of the bearing assem- 'lo lie's so that the retainer cannot move axially relative to the socket tidy However, the retainer can rotate freelylwith thefinner race rings 'of the ball bearings 2i. The blades'B"are'thusrotatably A to negative centrifugal torsion effect tending to rotate the blade into low pitch and has the center P of pressure on the blade forwardly from this axis A so that aerodynamic forces on the blade tend to rotate it into high pitch.

The retainers "26 for the blades B have tail por- MODSZBUBXtlldiYlgilltO the casing 2i. These tail portions 261) carry laterally projecting pins 30 and '3! in ri'ght'angular relation. The pins 3i project into slots Zld ofthe rear Wall 25b of the hub casihg'N, as nest'snow'n in Fi'gures' l and '5. Set screws 32 are threaded into the Wall 2 to to project into opposite sides of theslots "21d and ror m abutments for the pins 31 thereby limitin the a'nio'u'ntof rotation of the blades 13 about the axes of radial rotation A. Thesesetfscrews 32 can be "adjusted so that'the'amo'uiit or radial rotation of the blade "can be controlled to any desired 'degre'e. Likewise the screws can be adiusteuso that the desired high pitch and low pitch p'o'sitions for the blades can beobtain'e'dsince the setting "of screws 321on one side of the pins 3| will determine the high pitch positions forthe blades '33 while the setting of scre'ws on the other side of the pins 3i will determi'iiethe low pitch positions 'fortheblade's. 'lruesirdsprings (notshow'h) can be us'edto act "on the pins} for'urging the blades to rotate into high pitch positions, thereby assisting'thefareodyriarnic force 'Which'lnaintairls theblades high pitch positions. 7

Nuts '33 can be provided on the set screws 32 for locking the same inadjusteu position. I s

As best shown in Figure5,'a ring block 3 5 mounted in the hubba'Sing'Z'I and has'ac'entral aperture 35a extending ro'i n one end face thereor to receive the endo'f "the hub'portion'2lc. A shoulder 35b is provided at the bottom or the aperture 35a to thrust against the end'of the hub portion 2 In. A'second aperture-tee extends inwardly from the other end'of thefringblock 35 to receive the nut '22 freely therein and this aperture 35c has a Shoulder 35d at the bottom thereof bottoming a flange 22aof the nut. The ring block 35 is thus securedftothehlib 21c. Inadditioh, however, bolts suc as '36 are passed through the ring block and threaded into the back wall'2lb of the'hub 21-. I g

A top cover plate '31 held on "the ring'block by means 'ofcap screws such as 38threaded into or v the block. a bo'ttomc'over'39 is held on theb'ottom'or the'ring block by means o'f"boltsblichas As best shown in Figure 12, the ring bl'ock' 35 carries anoil't'ankor casing '41 inYanaperture thereof, and this 'ca'sing "4i lprojec'ts 'beyond" the bottom cover '39 intoth'e sp'acebe'tween the bottom cover and the end wall 21b "of the hub2l. A plunger "42 is 'sl'id'ably mounted in th casing 4| and this plunger flfz has a head H'Zaat'oiie'end thereof slidably engagihgthe walls ofi'the casing, together with a reduced diameterhollow shank portion 42b projecting towardth-e other e'nd of the casing in spacedfrela'tioninward from the casii'rg wall. "The head f42'aghas vents E3 erethrough connecting th esp'aceiin' the tank b'etw'eh the'liead and end 'wall'of the' tahkwith the space in tr e'ta surrounding the sh nk :211. -A"fsea'1 44 s "carried by the sharia-42oandjslidabiy e gages 'thewa'll of t tam; infs'ealin'g relation therewith. 'A "Coil "Spring 45is Contained"ih"the shank 42b to urge the plunger 42 toward the closed end of the tank. A plug 46 is threaded into aisle cover plate 31 for bottoming the coil spring Oil or other hydraulic fluid in the tank 4| is thus always maintained under spring pressure, so that air can never be delivered to the system in the event of leakage of oil. For example, as oil might leak out of the system, or contract due to temperature changes, the spring 45 will urge the plunger member 42 down toward the closed bottom of the tank for decreasing the size of the tank, since the seal 44 will render ineffective any portion of the tank interior lying between it and the open end of the tank. The oil is vented from the closed end portion of the tank through the holes 43 into the space surrounding the shank portion 42b of the plunger from whch the oil is fed into the system.

When it is desired to fill the system with oil or other operating fluid, the plug 46 and spring 45 are removed, a rod is threaded into the threaded well portion of the plunger, and the plunger is retracted toward the cover plate 31. Both plugs shown in Figure 15 are removed from the cover plate 31 and oil or other fluid is poured into one plug aperture while the other plug aperture acts as an air vent. The retracted plunger allows the tank 4| to be filled with oil. As shown in Figure 7, a pump assembly 41 is provided in another aperture of the ring block 35. This pump assembly includes a piston 48 slidably operating in the bore of a block 49 contained in the aperture and connected to a carrier 59 for a roller 5| adapted to ride on the cam track Ma. The carrier 50 is slidably mounted in a sleeve 52 carried by the block 35 and projecting therefrom into the space between the block and the back wall 2|b of the hub. A coil spring 53 acts on the carrier 50 to urge it outward from the sleeve 52 and seat its flange 50a on a shoulder 52a provided in the sleeve. The cam track Mo on which the roller 5| rides reciprocates the piston 48 to pump fluid supplied thereto from the tank 4| as will be more fully hereinafter described.

As shown in Figures 12 and 13, the ring block space between the block and the back wall 2 lb of i the hub. As shown in Figure 5, this button end 51a of the plunger acts on the pin 30 to rotate the blade B thereby changing the pitch of the blade.

As shown in Figures 7 to 11, a valve assembly 66 is provided in another aperture of the block ring 35. This assembly 66 includes a block 6| disposed in the aperture of the ring block 35 and slidably receiving a dumbbell type valve 62. The

valve 62 has a stem projecting through the bottom plate 39 of the ring block and attached to a carrier 63 for a roller 64 adapted to ride on the track portion MD of the control member l4. A

the block 60 symmetrically around the central dumbbell valve 62 as illustrated in Figures 8 to 11. As shown in Figures 9, 14 and 15, the cover plate 31 has a groove therein providing a passageway 66 to the valve seat 10 of the first valve assembly. A ball 1| is pressed by a spring 12 to seat against the seat 16. Fluid under pressure of the pump is sufficient to unseat the ball 1| so that the fluid can flow through the passageway 13 into anothmer groove 14 in the cover 31. This groove 14 has communication with the seat 15 of the second valve assembly, with the pump chamber of pump assembly 41, and with the third valve assembly.

As shown, oil can be drawn from tank 4| on the suction stroke of the piston 48 to flow through check valve 10 into passage 13 and groove 14. Pressured oil can be by-passed from plunger 48 through check valve 16 into passages 18 and 19 back to the tank, as hereinafter described. In Figure 15 the passageway 19 is shown diagrammatically as being in the ring block whereas, as shown in Figures 10 and 14, this passageway 19 is actually a groove in the cover 31 communicating with groove passageway 69. The connected grooves 19 and 59 by-pass the oil from passage 18 back to the tank, while the groove 69 also supplies oil to the pump through check valve 16.

Fluid can also flow from the groove 14 into a passage so to the valve seat 8| of the third valve assembly where it can force the ball 82 off of the seat against the pressure of the spring 83 and then flow into a passageway or groove in the cover. The groove 84 communicates with a passageway 85 in the ring block, which passageway communicates with a groove 86 around the sleeve 56 of the plunger assembly to a passageway 81 in the ring block connected through a passageway 88 to the chamber of the dumbbell valve. The valve 62 can connect the passageway 88 with a passageway 96 communicating through a groove 9| in the cover plate with the ends of both plungers to move the plungers against the pins 30 for rotating the blades into low pitch. Alternately, the valve 62 can block the passageway 88 and join the groove 9| and passageway 90 with a passageway 92. This passageway 92 in the ring block 35 communicates with a groove 93 around the sleeve 56 of the second plunger assembly 55 and the groove 93, in turn, communicates with a passageway 94 back to the oil tank.

Operation of the device The propeller pitch-changing device of this invention includes a hub assembly rotatably carrying propeller blades to turn about radial axes from high pitch to low pitch positions, the limits of which are determined by the positions and settings of the set screws 32. In normal operation, the aerodynamic and other forces on the propeller blades maintain the blades in high pitch position because the blades are arranged to have their centers of pressure forwardly of their axes of radial rotation.

When it is desired to rotate the blades about their axes of radial rotation into low pitch posisleeve slidably receives the carrier 63 and is tion, the pilot merely pulls the Bowden wire or control rod at. This rotates the control member M in the mounting plate I0, and rotation of the control member throws it axially forward because the bolt heads |6a seat in tapered slots I5.

The control member has an inclined cam track or ramp 4a on its front face together with a flat surface around this cam track. When the estates eontfol member is moved forwardly "the dam track 14c engages the roller ei of thepuinp assaintly -4"! whilef'the surface Mb around the cam track engages the roller 64 of the valve assembly 60. M g The cam track M'a reciprocates the plunger #8 'ofthepump and causes-the pump to pump oil from the tank 4|, Thus, on the suction shake jg: the pump, oilis drawn in pastthe check v'a1v'e "H and, on the pressnre stroke or the pump, the thus drawn-m oil is discharged against the check Valve 82. If the pressure is'tdo great, theoil will now past the check valve 56 back to the tank.

The oil under pressure flows from the check valve iifiintothe dumbbellvalvemperatihg chamberand the engagement of the roller 64 of the valve with the surface Mb of the control men ber moves the valve to a position so that the 'oil will flow tothe ends of the plunger-s '55 throw- "ing these plungers oiitwa'rdly again'stthe "pins 3'0 and thus rotating the blades B to low pitch positions as determined by the setting "of the "set LISCIEWS 32.

The pump will continue to operateas long as the "control member is in its forward position and resume their high pitch position, the -Bowdeh wire or'control rod 2D is 'againactuatedby the pilot to rotate the control member [4 in the reverse directionwhe'reupon the screw heads [6a and slots 15 retract the'control mei'nberto space the cam track l ia'away from the roller The spring 66 of the valve assemb1ymoves th'e'dufnbbell'valve'to place the passages 9| and 'llil in com-- munication with the passages-'92 and 94 backto the tank. The aerodynamic and other forces on the blades are thus suffi'cie'nt to rotate the blades ancithe pins 30 will force th'e pIungers-EE back into the ring block tfi. The oil in back of these 'pIunger's can flow freely through the valve back to the tank.

plane engine while the hub 'w'ill replace'the con;-

ventional propeller hub. I

It will, of course, be un'derstoo'dthat various details of construction may be varied through Ira wide range without departing from theprinciples of this invention and it is,'therefo're,-'not "the purpose to limit the patent'grahted hereon other'wise thannecessitated by thes'cope ofth'e appended claims.

I' claim as my invention:

1. A propeller pitch-adjustin'gdevice comprising a propeller'hu'b haying a'hollow central portion and radially "extendir'igsockets communicating with said central portion, blade-mounting 'devices rotatably carried in said sockets and having portions projecting into said hollowportion of the hub, pins extending laterally in angular "relation from said projecting "portions of the blade-mounting devices, set screws threaded in "said hub arrangedto engage opposite sides of "one set of pins on said blade mounting devices, hydraulically operate'd "plungersin said hub a'rrangedto engage thesamesides of the'other set of pins on said mounting devices for moving said devices to change the pitch of the blades carried therebya pump carried by said hub "for supplying hydraulic fluid'under-press'ure to said'plungers, a tank carried by said hub "for supplying hydraulic fluid to'said pump, a control valve carried by said hub for selectively connecting said plungers with said pump and said'tank, anda shift'able cam mounted adjacent said hub having a cam-track for actuating saidpump a'nd as'urface for moving said valve wherebyrotatio'n of -the hub andengag'ementof the pump and valve with the control device will create h-ydraulic'pressii're actuating the plun'gers for changing the -pitch oi the "propeller blades.

2 In an engine including "a shaft, a'pro'pelle'r pitch--'adjusting device comprising ahollow hub having radially extending sockets, a ring block member carried by said 'hub in the hollow interior thereof and arranged tosurround theeng'ine shaft, said block member having a plurality of recesses therein, pl'un'gers slidably mounted in some 'of said recesses, a control valve mounted in another recess, =apump-mounted instill another "recess, passageways-in said block operatively connecting said 'plun'gers, said pump and said control valve for fluid intercommunication, 'said'c'ontrol valve and said pump'havi'ng actuat- {i'ngmea'ns projecting from 'saidblock, propeller 1 blade mounting devices 'rotatably carried in said 7 sockets and ex'tending in'to the hollow interior 0f the hi-ib arranged to b'e acted "on by said plu'nger portions, and [ashiftable cam member arranged to be carrie'd byan aircraft engine adjacent said hub and shifted intoen'gage-r'nentwith --said projecting" portions of thepump'and control valve to open the valve and reciprocate the pump *for supplying fiuid under pressure to said plungers to force the plungers outwardly from the ring block against the inwardly projecting portio'ns ofthe blade mounting devices for rotating said blade mounting devices.

' JAMES H. BOOTH.

REFERENCES :CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date nei z zss Caldwell Mar. 9,193": Re 21,108 Zipay 'May 30, 1939 Re. 22,034 Hoover Febf24, 1942 1,803,858 MacClatc'hie 'May fi, 1931 1,967,461 'Ba'llew July 24,1934 2,0o2;112 Patriarche May 28, 1935 2,023,785 Hoover Dec/10,1935 2,032,354 fcaiawen -QFeb. 25,1936 2,075,682 Welman -QMar. 30, 1937 2,229,058 Dicks Jan. 21, 1941 12,307,102 Blanchardet' a1. Jan/5,1943 2.347404 Hoover --i -i Apr. 18,1944 mesa-939 Augfl, 1944 2,404,290 Hoover *Ju1y'16,' 1946 FO R EIGN PATENTS Number Country Date 1 119,164 AuStra1ia NOV.- 23,1944 601,246 France 'Feb. 25,1926 635,992 Germany d. Aug. 30, 1934 782,127 France May 28, 1935

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