US2435360A - Variable pitch propeller - Google Patents

Description

Feb. 3, 1948. LE|NER 2,435,360

VARIABLE Pl TCH PROPELLER Filed Dec. 30, 1944 3 Sheets-Sheet 1 INVENTOP- .HENRY GLEINEP- ATTORNEYS H. G. LEINER 2, 35,360

VARIABLE PITCH PROPELLER Filed Dec. 30, 1944 3 Sheets-Sheet 3 Feb. 3, 1948.

ATTORNEYS HENRY G.LEINER Patentecl Feb. 3, 1948 2,435,360 VARIABLE PITCH rRorE ER.

Henry G. Leiner, Racine, Wis, assignor of onehalf to Virginia A. Leiner, Racine, Wis.

Application December 30, 1944, Serial No. 570.732

This invention appertains to air craft and more particularly to a novel airplane propeller.

One of the primary objects of my invention is to provide a fully automatic means for controlling the pitch of the propeller blades according't'o the speed (i. e. R. P. M.) of the'propeller, whereby the propeller will functionto the'best of advantage for take-off, cruising, landing; etc.

Another salient object of my invention is to provide an airplane propeller having incorporated with the hub thereof an automatic means for controlling the pitch' of the blades in accordance with the conditions of operation and'flight; the construction being suchthat not only a strong and simple mechanism will be had, but one which can be purchased at 'a comparatively low cost thereby rendering the same particularly adaptable for use for small airplanes.

A further object of my invention is to provide a variable pitch propeller havingthe blades thereof mounted in the hub for turning movement, with means responsive to centrifugal force for turning the blades according to the speed of rotation of the propeller. 3 r

Another further object of my invention is to provide means for operatively connecting the blades together, whereby the turning action of the blades will be coordinated-so that the 'blades will always be at'the same pitchrelati've to one another. I

A still further object of my invention is to provide a variable pitch propeller which is fully automatic and which does not require'anvmanual operation on the part of the'pilot.

A still further important object of my invention is to provide a variable pitch propeller which can be used on an ordinary propel1er shaft thereby eliminating the necessity of providing a pro peller shaft of a special design, the'pro'pel1er also functioning with an' ordinary designof invention.

With these and other objects'in view, the invention consists in the novel construction, arrangement, formation of parts as will be hereinafter more specifically described; claimed and illustrated in the accompanying drawings, in which drawings:

Figure 1 is a fragmentary side elevational vie of my novel propeller with'parts thereof broken away and in section to illustrate structural detail.

Figure 2 is a detail sectional 'view through the propeller taken substantially'on the line 2 -2013 Figure 1 looking in the direction of the'arrows.

Figure 3 is an'end 'elevational view of the propeller looking inwardly along one blade toward thehub.

W 50mins. (01. 170 -162) Figure 4 is an enlarged detail longitudinal sectional view through the control mechanism for one blade, the section beingtaken substantially on the lined-4 of-Figure 2, looking in the direction of the arrows, the parts of the control-mechanism being shown in their position during the warming up of the engine. i

Figure 5 is a view similar to Figure 4 but showing the parts in position during the increasing of speed of the engine for take-off;

Figure 6 is a view similar to Figures 4 and 5 but showing the parts in their position for increasing the pitch ofthe propeller.

Figure 7 is a diametric sectional view through the hub of a propeller showing a modified-form of my invention with the 'controls incorporated in the stems'of the propeller blades, the section being taken substantially on the line of Figure 9, looking in the direction of the arrows.

Figure 8 is a detail sectional view through one of the'blades and its control mechanism, the View being taken substantially'on the line 8 8 of Figure 9, looking in the direction of the arrows.

Figure 9 is a sectional view taken on the line 9-8 of Figure l'looking in'the direction of the arrows. I

Figure 10 is an end elevational view looking inwardly from the tip of one propeller blade toward the hub.

Referring to'the drawings in detail, wherein similar reference characters "designate corresponding parts throughout the several views, the letter P generally indicates my novel propeller and the same includes a propeller hub l5.- This hub l5 includes the axially disposed tapered sleeve l6 for the propeller shaft iii. The hub is held 'on'the shaft 1 1 by a nut l8 which is threaded tightonthe shaft against the sleeve H. In the present form of my invention the propeller includes two blades l8 and l9,and hence the hub [5- also includes diametrically extending sleeves 20 for the stems of the propeller blades.

In accordance with my invention the stems of the propeller blades and I9 are imbedded in thimblesll which are rotatably mounted in the sleeves 20 A thrust bearing ZZ isprovided for each thimble and the thrust bearings and the thimbles with the propeller blades are 'held in the sleeves [5 by a split nut 23. Thus from the description so far, it can be seen that thepropeller blades are mounted for turning-movement within the hub sleeves 20. To coordinate the turning action of the propeller blades, the inner ends of the thimbles have formed thereonsector gears-23 which mesh with 'a'beveled'gear 24 rohas associated therewith a hub cap 21 which functions as an oil reservoir and the controls for the propeller blades have their inner ends projecting into and communicating with the interior of the hub cap. The control mechanisms ex-L tend radially from the hub cap and substantially parallel with the propeller blades.-

spring. The inner end of the control weight is also reduced in diameter and is slidably mount-' ed Within a rin 49 firmly anchored to the walls of the cylinder 45 inward'of the opening 46. One face of the reduced portion 50 of the control weight has formed therein a longitudinally extending groove 5| which establishes, at certain times, communication between the cylinder 45 on opposite sides of the'guide ring 49. Formed in the control weight 41, intermediate its ends, is a diagonally extending passageway 52 which connectsthe opposite ends of'the piston'weight on opposite sides of the enlarged central portion of the control weight. Flow of fluid through this passageway iscontrolled by a ball check valve 53.

-The ballcheck-valve 53 is normally held on its seat by centrifugalaction. A longitudinally ex- Each control mechanism includes a rnaster cylinder 2! having slidably mounted therein a combination weight and piston 28. This weight is normally held inwardly toward the axial center of the propeller by an expansion coil spring 29. It will be noted that the outer end of the weight is reduced in diameter to form a shoulder seat for the spring 29. The inner end of the weight is provided with a diagonally extending slot 30 into which projects the control pin 3| for a propeller blade. The inner end of the control pin is securely anchored to the thimble of the adjacent propeller blade and the pin moves in its hub sleeve through a short circumferentiallyextending slot 32. Obviously as the weight 28 moves outwardly under centrifugal force the walls of the diagonal slot 30 will move the pin 3! in the slot 32 for changingthe angle --or pitch of its propeller blade. I i

The combination weight and piston 23 has formed in its outer end a longitudinally extending chamber 33 inwhich is slidably mounted a piston valve 34. A valve casing 35 is threaded on the extreme outer endof the weight 28 and holds in place a valve disc 36, the valve opening in which is normally closed by the piston valve 34. A ball check valve 31 is mounted in the valve casing and is normally heldon its seat bya light expansion spring 38'. Communicating with the inner end of the chamber 33 is alongitudinally extending bore 38 which opens into the reservoir communicates with a radially extending bore 42 which is adapted to register with an opening 44 formed in the master cylinder, at certain times, as will be later set forth.

Arranged alongside of and parallel with the master cylinder 21 is an auxiliary cylinder 45. This cylinder has formed therein ano'pening 46 which is in alinement with the opening 44. slidably mounted'within the auxiliary cylinder 45'is a controlling weight 41 and this weight also moves tending bore 54 connects the inner-end of the control-weight with the inclined passageway,

Obviously, the control mechanisms 26 can be secured in place on the propeller hub inany preferred manner, suchas by theme of bracket straps 55. 7 r

The control mechanisms function as follows. Considering that the engineis idling or running at a warm-up speed, the parts of the control mechanism willbe positioned as shown in Figure 4. The piston weight 28 and the control weight A! are at the extreme inner ends of their cylinders and consequently the propeller blades'are at their lowest pitch; it being understood that the centrifugal force acting against control weight 7 41 and piston weight 23 at low; speed is insuiiicient to overcome the tension of the springs 29 and 48.. Inthe warming up R. M., the piston valve is moved outwardly under centrifugal force and closes opening 40 (see Figure 5). This prevents the escape of oil in the chamber at the outer end through the passageway 38 formed in the main' weight. 7 1 During take-off, the speed of the motor is increased until the propeller is rotating 52.352500 R. P. M. The centrifugalforce increases on piston weight 2 8 and-control weight 41, tending to increase pitchof propeller. However, the chamher in the cylinder 21 is filled with oil which looks the piston .weight 28 against outward movement :7

and counteracts the tendency of the piston-weight 28 to increasethe'pitch of the propeller. In this:

manner, the propeller is held in low pitch for take-air.- The resultant high in. r. M. of the motor increases the power and increases take-01f efficiency. During the take-off, centrifugal force acts upon the control weight'47 (see'Figure 5) and moves it outwardly toward the tip of, the propeller against the tension of the'coil spring 48 pushing the oil in the outer end of the cylinder outwardly under centrifugal force and controls the action of the large piston weight28 as will also be hereinafter more fully pointed out. The

control weight 41 is normally held inward against 7 centrifugal action by an expansion coil'spring 43. The outer end of the control weight is re- 45 totheinnerendof the cylinder. past the ball kv lv .3. I

During cruising; the throttle is pulled back to" a cruising'speed, say 2,000 R. vP. M. andthe pro-' peller will go into cruising pitch (a'calibratd pitch for R- P. M. or constant speed-control) by the decrease ofcentrifugal force-on the control weight, for the reason that as th centrifugal a l-ease force decreases on the controlv weight 41.,the spring; 48 will tend to move the control weight inwardly'toward the axial center of the propeller and the oil in theinner. end of the cylinder 45: will be forced from the inner end of the cylinder.

through openings 46 and'44 into the bore and passageway 4|. The check, valve 53 willbe held on its seat due to oil pressure. Thus the oil will beforced into the pistoniweight 28 and the oil pressure. acting on valve piston 34 willmove the valvev piston inwardly and aline the T-shaped passageway 39with the port or opening 40. This will release the oil located in the outer end of the maincylinder zlallowing the centrifugal action to move piston weight 23 outwardly toward the .tip of the propeller (see Figure 6). The outward movement of the piston weight 28 will transmit the desired rotary movement to the propeller blades and increase the pitch thereof. As the piston weight moves outwardly, bore 42 moves away .from the opening 44 and the oil in the pis ton weight 28 is locked therein. This trapped oil keeps the valve piston 34zinward in the piston weight (as shown in Figure 6) and keepsthe T- shaped passageway in communication with the opening 40, so that piston weight 28 can increase or decrease pitch of the propeller. This is accomplished by increase or decrease of R. P. M. in conjunction with the tension of the calibrated spring 29, giving the propeller constant speed performance.

The replacement of spring 29 by an equal spring calibrated for 1,000 B. P. M. will give my propeller low pitch for take-off and an increased pitch (high pitch) for cruising.

During landing or gliding, the throttle will be moved back towarda closed position and when thespeed of the propeller drops under say 1,000 B. P. M., piston weight 28 will move inwardly to its normal position under influence of the spring 29 to the position shown in Figure 4, and the blades will be turned to their extreme low pitch. As the piston weight 28 moves inwardly in its cylinder toward the hub of the propeller the outer end of the cylinder 2'! will again fill with oil due to the fact that oil will flow from the reservoir through the passageway 38, through the piston valve 34 into the outer end of the cylinder 21. Passageway 4| and bore 42 will again be in communication with opening 44 and the control is all ready for high R. P. M. and high horsepower in case of emergencies. The check valve 31 carried by piston weight 28 comes into play only when propeller is overspeeded, say over 2500 R. P. M. and this check valve constitutes an overspeed control.

Say that the plane is put into a dive in the take-ofi pitch and the speed of the motor is increased and the various parts of the control are in the position shown in Figure 4. If the speed of propeller, due to the dive, exceeds 2500 R. P. M., then the piston weight 28 tends to move outward increasing the pressure on the oil pressure in the outer end of the cylinder 21. The increased pressure of the oil will unseat the ball check valve 31 and the oil will slide back piston slide valve to aline the T-shaped passageway with port 40 allowing the oil trapped in the outer end of cylinder 2! to escape through piston slide valve. Pistonweight 28 can now move outwardly to increase fully the pitch of the propeller. This will result in decrease of R. P. M. to save the engine.

The R. P- M.s mentioned in this specification are merely illustrative and thedesign can cover any desirable range of R. P. M.

of the propeller blades.

Initially-. the .lowpitch; on: the: propeller: can 'be setor adjusted bymovingthe controlmechanisms 26scircumferentially of. the hub.v This can be ac.- complishedby looseningthescrews 56..utilized forholding the brackets 55 in placeand aften the control mechanisms have beenmoved therscrews 56 canagainbe tightened. 0bviously.I.do;notz limit-myselr'to the use ofbrackets in that ears.

or the like can be formed directly on the cylinders of the control mechanism. propeller can be controlled by the length of travel of the pins 31 in the slots 30.

In Figures 1. to 6, inclusive, my control.mecha-.

nism has been shown built exteriorly of the prof peller hub but obviously the controls can beincorporatedin a hollow blade propeller with the mechanism working inside of the blades. Such a constructionis shown in Figures?v to 10; inelusive.

This propeller is generally indicatedby-the reference character V and the-same: includes an axial hub sleeve 60'-for the reception of the propeller shaft-Bl. the hub on the shaft. Also formed on the hub sleeve 60 are radially'extending' blade sleevesor sockets 63 for the stems of thepropeller blades 64-and-65,- which meet the-hollow type. The

stemsor roots; of the blades 65 have pressed thereincylinders 66 for-the reception of slidingv piston weights 61.

Expansion spring-s 68 0f a pre-determined tension are utilized for normally holding the'piston weights against the action of centrifugal force in-the inner ends of the cylinders toward the propeller shaft. These-blades are mounted for turning movement in the sockets 63 and thrust bearings B9'are-utilized for the blades. Nuts, 10 are threaded into the sockets for holding, the blades against displacement. Also secured to the inner ends of the Stems of the blades, are. collars H and these collars have formed thereon sector gears 12 which mesh at all times with a beveled gear -13"rotatably mounted upon the shaft nut 62. Lock nut HI-canbe threaded on the shaft nut for holding-the gear 13 in place. Thisgear meshingwith the sector gears 'l2 functionsto coordinatethe turning of the propeller blades.

To insure straight outward movement of the piston weights, guide pins 15 are carriedby the hub sleeve 10 andthese pins are received in-suitable. guide openings 16- formed in the piston weights. Thesepiston weights 6! have formed therein inclined grooves 11 and these grooves receivepins 18 formed on or carried by the stems Consequently when the piston weights 6'! move outwardly against the tension of their springs 68, a turningmovement will be imparted to the blades through-thepinsfor changing the angle or pitch of the propeller blades.

Formed within each piston weight 51 isa cyl-' der [9 and slidably mounted in each cylinder-ls a control weight 80. Each weightBU-has its outer end reduced in diameter to form a shoulder seat against which is fitted an expansion coil spring 8|. control weight inwardly against the action of centrifugal force. Formed on theinnerend of each control weight is a reduced guide stem 82 and this stem is provided with a longitudinally extending passageway 83 which opens into theinner end of the cylinder 66. The-formation of-the stem 82 and the-reducedportion of thecontrol weight provides a central body-portion and this body portion is provided with a diagonally extending The high pitch of the 1 A nutBZ is employed for holding The spring functions to normally hold the way 85 which connects the ends of thecylindr 19 together on opposite sides of the body portion 84. A check valve 86 normally'closes this passageway and centrifugal force tends to hold the ball check valve 86 on its seat. E ach piston weight also has formed therein a passageway 81 which communicates with the inner end of the cylinder 19 and the outer end of the main cylin-v der 66. A spring pressed check valve 88 normally closes this passageway.

Also formed in each piston weight 61 isa chamber 89 in which is slidably mounted a slide piston valve 90. The inner end of the guide way 89 communicates with the inner end of its main cylinder 66, The slide piston valve 90has formed therein a T-shaped passageway 9! and thispassageway opens out to the inner end of the slide piston valve and is, adapted to communicate at certain times with a passageway 92 formed in the piston weight 61, This passageway 92 also opens out through the outer end of the piston weight 6'! and consequently communicates With the outer end of the cylinder 66. A port as isemployed for connecting the passageway 81 inwardly of the ball 7 checkvalve 88 with the chamber 89.

The control mechanisms in Figures 7 to 10, inclusive, function in identically the same manner as the control mechanism shown in Figures lto 6, inclusive. Hence, when the engine is warming up the various parts of the mechanism will be positioned as shown in Figures '7, 8 and 9. The piston slide valve 90 moves outward toward the tip of the propeller due to centrifugal force as shown in Figure 8 and the passageway 92 willbe closed locking the oil in the outer end of the cylinder 66. As the R. P. M.- increase for take oil, centrifugal force also increases on the piston weight 61 tending to increase the pitch of the propeller. However, as the oil istrapped in the outer end of the cylinder this tendency is counteracted In this manner the blades are held in low:pitch for take-oil. The resultant high R, P. M. of the motor increases the horsepower and increases pitch (a calibrated pitch for the R. P. M. or con- 7 stant speed control) by the decrease of centrifu- From the foregoing description it can be'seen that I have provided an exceptionally simple and durable form of control mechanism which can be incorporated with-a cost. I

Changes in details may be made without departing from the spiritor the scope of my invention, but what Iclaim as new is:

1. In, a variable pitchpropeller, a hub, blades mounted in said hub for turning movement; meanscoupling said blades together for coordimeans sensitive to centrifugal action for releasing fluid from one end of the cylinder to the other according. to the'speed of rotation of the propeller, saidpiston weight also having a port therethrough and a spring pressed check valve for controlling the flow of fluid therethrough,

said spring pressed check valve'being operable when the speed-of the propeller exceeds a normal take-oil, speed.

71 2. In a variable pitch propeller, a hub, propeller blades mounted in the hub for turning movement, a cylinder arranged radially .of the hub, a piston weight ,slidably mounted insaid' cylinder and movable outwardly under centrifu .gal force, means for turning the propeller blades from said piston weight upon sliding movement thereof, spring means normally holding the pis ton weight at the inner end of the cylinder, said cylinder having a liquid therein for preventing outward movement of the piston weight under force, and means operated by movement of said therethrough and a Spring pressed check valve for controlling the flow of liquid through said.

gal force on control weight 80. Spring 8| will remounted for turning movement in the hub for turn the control weight to the inner end of the chamber forcing the-oil in the inner end of the chamber into passageway 81 and this oil will force back slide piston valve 90 and aline the T -shaped passageway 9i with the passageway 92. This will i permit the flow of the trapped oil from the outer end of the cylinder 66 to the inner end of the. cylinder and the piston weight 61 will move out wardly increasing the pitch of the propeller. As

soon as the R, P. M. decreases below a certain T-shaped passageway 9i with the passageway 9i so that-the weight 67 can move outwardly to increase the pitch of the'propeller to its fullest extent; I p' the influence of centrifugal force, a second cyl inder arranged radially of the hub, a control weight slid-ably mounted in said second cylinder and movable under the action of centrifugal control weight for permitting the escape of liquid from the outer end of the first cylinder to permit outward movement of the piston weight,

'and said piston weight having a passageway passageway and movable to an'unseated position when the pressure of liquid in the outer end of the cylinder exceeds a pre-determined degree.

3. In a variable pitch propeller, a hub, blades varying the pitch thereofla control mechanism for regulating the pitc n of th blades including a main cylinder and an auxliliary cylinder, said cylinders being arranged radially of the hub, a

sliding piston weight in the main cylinder mov blade received in said slot whereby upon radial movement of thepiston weight the blade will be turned, spring means normally holding the pis.

ton weight-attheinner end of the cylinder, said i cylinder having a liquid therein for resisting outward movement of the piston weight under,

centriiugal force, a control weight slidably mounted in the auxiliary cylindenand means including a slide valve for releasing trapped liquid in the cyli d r by movement of. said control 7 weight so thatthe piston weight can function i under centrifugal jiforce: when 1 the propeller propeller at an extremely low reaches a certain number of R. P. M., said auxiliary cylinder having liquid therein, means including' a check valve for permitting the transfer of liquid from one side of the auxiliary cylinder to the other according to the position of the control weight under the action of centrifugal force to force oil against said slide valve, said slide valve functioning to cover and uncover ports for permitting communication of the outer end of the main cylinder with the inner end thereof.

4. In a variable pitch propeller, a hub, blades mounted for turning movement in the hub for varying the pitch thereof, a control mechanism for regulating the pitch of the blades including a main cylinder and an auxiliary cylinder, said cylinders being arranged radially of the hub, a sliding piston weight in the main cylinder movable outwardly under centrifugal force having a diagonal slot therein, a rigid pin carried by a blade received in said slot whereby upon radial movement of the piston weight the blade will be turned, spring means normally holding the piston weight at the inner end of the cylinder, said cylinder having a liquid therein for resisting outward movement of the piston weight under centrifugal force, a control weight slidably mounted in the auxiliary cylinder and movable outwardly under centrifugal force, and means including a slide valve for releasing trapped liquid in the cylinder by movement of said control weight so that the piston weight can function under centrifugal force when the propeller reaches a certain number of R. P. M., said auxiliary cylinder having liquid therein, means including a check valve for permitting the transfer of liquid from one side of the auxiliary cylinder to the other according to the position of the control weight under the action of centrifugal force to force oil against said slide valve, said slide Valve functioning to cover and uncover ports for permitting communication of the outer end of the main cylinder with the inner end thereof, said piston weight also having an additional passageway therein and a check valve for controlling the flow of liquid through said additional passageway only when the pressure on the liquid in the outer end of the main cylinder exceeds a pre-determined amount.

5. In a variable pitch propeller, a hub, propeller blades having hollow stems, means ro- Number tatably mounting said stems in the hub whereby the pitch of the blades can be changed, cylinders carried by the hollow stems, sliding piston weights slidably mounted in the cylinders, means operatively connecting the piston weights with the stems of the blades for turning said blades upon sliding movement of the piston weights in the cylinders, spring means normally holding the weights inwardly toward, the axis of the hub, said cylinders being filled with liquid for resisting outward movement of the weights under centrifugal force, and means sensitive to centrifugal force for allowing the escape of liquid from the outer ends of the cylinders when the propeller reaches a pre-determined number of R. P. M. including a slide valve carried by each piston weight sensitive to centrifugal force for controlling the flow of fluid through the piston weights, said piston weights also having an independent passageway therethrough connected with the outer end of the chamber for the slide valve, and a spring pressed check valve for controlling the flow of fluid through the passageway and to the outer end of the chamber of the slide valve operable when the speed of the propeller exceeds a normal take-off speed.

HENRY G. LEINER.

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

UNITED STATES PATENTS Name Date Lanzius Feb. 5, 1924 Newton Nov. 24, 1931 Schroeder Dec. 1, 1931 Landrum Aug. 9, 1932 Landrum Apr. 11, 1933 Caldwell Feb. 25, 1936 Smith Dec. 13, 1938 Martinotti May 30, 1939 Bottrill Sept. 1, 1942 Bottrill Sept. 1, 1942 Blanchard et al Jan. 5, 1943 FOREIGN PATENTS Country Date Great Britain July 7, 1938 France Oct. 10, 1932 Number

Images