US2023785A - Hydraulic unit for variable pitch propellers - Google Patents

Description

Dec. 10, 1935- w 3 HOOVER 2,023,785

HYDRAULIC UNIT FOR VARIABLE PITCH PROPELLERS Filed June 7, 1953 I 3 Sheets-Sheet 1 INVENTOR BY MA. I

ATTORNEY Dec. 10,1935.

HYDFAULIC UNIT w. s. HOOVER Filed June '7, 1933 5 Sheets-Sheet 2 Dec. 10, 1935. w. s. HOOVER 2,023,785

HYDRAULIC UNIT FOR VARIABLE PITCH PROPELLERS Filed June 7, 1935 3 Sheets-Sheet 5 INVENTOR M 5. A ma.-

Patented Dec. 10, 1935 PATENT OFFICE HYDRAULIC UNIT FOR VARIABLE PITCH PBOPELLEBS Walter s. Hoover, Meadvilie, Pa. Application June 7, 1933, Serial No. 674,883

9 Claims.

This invention relates to variable pitch propeller mechanism, and the present application is a continuation in part of an application bearing Serial No. 578,513, flledDecember 21, 1931, allowed February 27, 1934.

In the application referred to, I have disclosed a hydraulic unit in the form of an angularly movable abutment or piston element which is actuated by the fluid pressure of the oil in the engine to effect angular movement of the propeller blade hub to vary the pitch setting. The hydraulic unit therein disclosed is responsive to variations in the engine speeds to effect propeller blade pitch settings in accordance with the speed and load characteristics of the engine.

In accordance with the present invention, I uti lize the rotary abutment or piston elementof the hydraulic unit disclosed in my former application and employ a manual control for varying the fluid pressure acting upon the hydraulic unit in accordance with the pitch setting it is desired to produce.

The invention will become more apparent from a consideration of the accompanying drawings 7 constituting a part hereof in which like reference characters. designate like parts and in which:

Figure 1 is a side elevational view partially in section of a variable pitch propeller mechanism embodying the principles of this invention;

Figure 2 a sectional elevational view taken along the lines 2-2 of Figure 1;

Figure 3 a cross-sectional view taken along the lines 3 3 of Figure 1;

Figure 4 a top plan view showing the propeller blade root in cross-section; and,

Figure 5 a front elevational view of the propeller hub.

With reference to Figure 1 of the drawings, the structure therein illustrated comprises an integrally forged propeller huh I with lugs 2 on the rear portion thereof, and having oppositely disposed threaded hub portions 3 for receiving bearing sleeves 4 which are provided with shoulders 5 that abut against the ends of the hub element.

The bearing sleeves 4 are assembled with their threaded portions co-acting with the threads 3 of the hub and when screwed down with their shoulders 5 abut the ends of the hub portion. The sleeves l are provided with an inwardly depending radial flange 1 for holding a series of roller bearings 8 which constitute an anti-friction mounting for the root portions 9 of the propeller blades. The blade roots 9 are further provided with anchorage grooves or abutments ll that interact with complementary shaped abutments of split rings II that constitute a shoulder or end abutment for the anti-friction bearings I.

Disposed around the split rings H are bevelled gear wheels l2 having teeth It that interact with a the teeth of a mating gear wheel ii. The bevel gear II is provided with gear teeth I! constituting it an internal ring gear which teeth interact with the teeth of planetary gear wheels it that are Journalled on stud shafts l'l retained in one 10 wall l8 of a hydraulic unit of which the casing l3 constitutes the front part or housing.

The gear wheels l6 also mesh or interact with the teeth of a sun gear which is keyed at 2! to a shaft 22 extending through the walls l3 l5 and IQ of the hydraulic unit, and the design shown in the drawings is such as to effect a five to one gear reduction between shaft 22 and the gear wheel l2.

with reference to Figure 3 of the drawings, :0 which is a cross-section through the hydraulic unit, a pair of stationary abutments 23 cooperate with a pair of movable abutments 24 that are joined to the shaft 22 to adapt them to rotate therewith, .the movable abutments being provided 25 with flow passages 25 in which are disposed safety ball valves 26 that are normally biased against their seats by springs 21. The stationary abutments 23 are provided with drilled leads 28 connecting fluid passages 29, and the shaft 22 is 30 provided with passages 30 to establish communication between the stationary and movableabutments 23 and 24 on opposite sides thereof.

Again referring to Figure 1 of the drawings, the reference numeral 3| designates the engine as shaft which is hollow and has a tube 32 disposed centrally and axially thereof. The inner end of tube 32 is disposed in a counterbore provided in a sleeve or distributor head having fluid passages 34, 35 and 3 6, the end of the sleeve being closed by a screw plug 31 as shown.

One end of the head 33 is-provided with a screw thread 38 which interacts with a thread formed on the-end of a tube 33 that extends part way' into the hollow interior of the engine shaft 3|. The engine shaft 3| functions as a conduit that communicates with the crank shaft of the engine for the flow of oil in the direction of the hydraulic unit, the oil passing through the space 40 between the central tube 32, and the member 33 into the hollow of the distributor head or sleeve 33, and from which it is distributed in a manner to be explained in connection with Figures 4 and 5 of the drawings.

Disposed around the rear portion of the pro- 5 peller hub casting is a sleeve 4| having a dishshaped flange or plate 42 provided with perforations 43 for fastening the same to the nose of the motor, and the flange or plate 42 is stationary when the propeller hub structure is rotated by the propeller shaft 8|.

Mounted on the stationary sleeve 4| are a pair of control cams 44 and 45 which cooperate with plungers 46 and 41 that are disposed in cylinders 48 and 48a of the lugs 2 of the hub casting. The ends of cylinders 48 and 48a are closed by caps 49, and fluid passages 50 lead from the cylinders to the fluid passages of the distributor head 33 in the center of the hub structure and to the hydraulic unit, as will be hereinafter described.

The stationary cams 44 and 45 are angularly movable on sleeve 4| by levers 5| and 52, these levers being manually operable to constitute the control for varying the pitch setting, lever 5| being for forward pitch control setting and lever 52 for reverse pitch control setting.

The flow connections of the cylinders 48 with the hydraulic unit and the oil supply are shown in Figures 3 to 5 of the drawings and are as follows: The passage 36 of the oil distributing head 33 which communicates with the passage 40 leading to the source of oil supply in the crank case is shown connected at one end by drilled passages 53 and 54 to one of the plunger cylinders 48 which acts as a booster to deliver the oil under pressure through the passages 55 and 56 to the passage 23 of the hydraulic unit into which it passes through passage 28 of the stationary abutment. A ball valve 51 is normally held by a spring 58 in position to close the passage 56 and open the drain passage 35' to tube 32. When the pressure in lines 55 and 56 exceeds the pressure in the passage 34, the ball valve 51 will be displaced to close the passage 34 and permit the fluid under pressure to be conducted downwardly through passage 29 to the passages 28 of the stationary abutments.

As there are two stationary abutments and two passages for communicating fluid pressure into the hydraulic unit, they each have a flow system as described in connection with Figure 4 of the drawings to get a reversal of the pitch setting.

With reference to Figure 3 of the drawings, when the fluid under pressure enters the passage 29 and thence through the drilled passage 28 into the space between the stationary and movable abutments on one side, the fluid pressure will pass through the communicating passage 38 into the opposite space to exert pressure against the movable abutments, causing rotation of the movable members in a given direction. While pressure is so exerted on one face of each of the movable abutments, the pressure on the opposite sides of. the movable abutments is relieved through the passages 28 and 29 that are in communication with the return conduit 32 through passage 35 to return the fluid to the engine crank case or pump.

When the fluid pressure is equalized on both sides of the rotary'abutments 24, the blades are locked against movement for pitch setting, and if for any reason the fluid pressure is not released on the side against which the booster pressure of the pistons 46 and 41 is acting, the safety ball members 26 will depress the spring 21 and permit a balance of the fluid on both sides of the rotary abutments.

As shown in Figure 2 there are two pumping units comprising cylinders 48 and 48a and pistons 46 and 41 each cylinder of which is connected to the flow passage 28 of one of the stationary abutments of the hydraulic unit. By moving control levers 5| and 52 the cams 44 and 46 to which they are connected will control movement of their respective pistons 46 and 41. In Figure 2 of the drawings the lever 5| controlling the forward pitch setting is shown in the position where its cam is out of 'contact with piston 46 and the fluid in the passages connecting cylinder 48 is of the pressure of the fluid delivered through passage 40 from the engine which is from seventy flve to ninety pounds. Lever 52 is shown in the position where cam 45 produces stroke of booster plunger 41 and the fluid passages connecting the hydraulic unit with this cylinder delivers fluid at a pressure up to flve hundred pounds per square inch depending upon the setting of the reverse pitch control lever 52.

The employment of the flve to one gear reduction between shaft 22 of the hydraulic unit and bevel gear I2 and the flve hundred pounds per inch pressure produces approximately fifty thousand inch pounds mechanical leverage in the adjustment control of the blade pitch. The mechanical leverage may be increased by employing double acting hydraulic pistons to obtain a surplus mechanical leverage.

Again referring to Figures 3 to 5 of the drawings, when one of the control levers has been set to cause a boosting of the oil pressure for forward or reverse pitch setting, movement of the rotary abutments 24 is effected by the pressure being relieved on the opposite side of the abutment through passages 28 and 29 thence by displacement of ball valve 51 through passage 35 to line 32. Figure 4 shows the flow passages for one of the booster cylinders, hydraulic unit abutment and return through line 32 as controlled by one of the control levers, and Figure 5 show that the passages are the same for the flow as controlled by the other of said levers.

The desired pitch setting when once obtained is maintained by the locking effect of the oil pressures on both sides of the rotary abutments 24 which can be produced by adjustment of both levers 5| and 52. In the position of the levers in Figure 2 of the drawings, the hydraulic unit would be in its extreme reverse pitch setting, while in Figure 3 it is shown in neutral or normal pitch setting position.

It is evident from the foregoing description of U my device that the employment of the oil pressure booster renders the hydraulic unit applicable for use in planes where manual pitch set ting of the propeller blades is desirable.

I Various modifications in the details of construction and arrangement of parts may be contemplated within the spirit of my invention.

I claim:

1. In a variable pitch propeller mechanism, a

hub structure for mounting a plurality of propeller blades for rotary movement about their longitudinal axis, gear mechanism connecting said blades to render them movable simultaneously, an hydraulic unit for actuating said gear mechanism, a source of fluid pressure for said unit, means for selectively applying pressure to said unit to render same operative in opposite directions, pump mechanism operative in response to rotary movement of said propeller mechanism for varying the pressures to produce a desired forward or reverse pitch setting of the propeller blades and ,manual control means for regulating said pump mechanism.

2. In a variable pitch propeller mechanism, a

hub structure for mounting a plurality oi! propeller blades for rotary movement about their longitudinal'axes, an hydraulic unit embodying a plurality of stationary and movable abutments connected to subject said blades to movement simultaneously to vary their pitch setting, fluid pressure means for displacing said abutments, fluid pressure cylinders connected to said fluid pressure means, pistons in said cylinders, a plurality of cams cooperating with said pistons and manual control means for varying the cam setting to vary the length of stroke of said pistons thereby varying the fluid pressure delivered to said hydraulic unit'abutments.

3. In a variable pitch propeller mechanism, a hub structure for mounting a plurality of propeller blades for rotary movement about their longitudinal axes, gear mechanism connecting said blades to render them movable simultaneously, a hydraulicunit actuating said gear mechanism, embodying a plurality of movable piston elements, fluid pressure means for actuating said pistons, a plurality of fluid pressure cylinders connected to said fluid pressure means, pistons for said last named cylinders, a plurality of stationary cams cooperating with said last named pistons, and manual control means for varying the setting of-said cams to. thereby vary the stroke of said pistons to change the direction of movementand the pressure acting on said first named piston elements.

4. In a variable pitch propeller machanism, a hub structure for mounting a plurality of propeller blades for rotary movement about their longitudinal axes, differential gearing connecting said blades to render them movable simultaneously, a hydraulic unit for actuating said gearing embodying a plurality of displaceable piston elements, fluid pressure cylinders carried by said hub structure having piston elements disposed therein, a plurality of stationary cams and control means therefor, said cams being in cooperative engagement with the pistons 01' said fluid pressure cylinders, one of said controls being operative to direct the flow and vary the intensity of fluid pressure on the hydraulic unit to pro-' duce a forward pitch setting of the propeller blade and the other of said controls being efiective to control the direction and intensity of fluid pressure to said unit to eflect a reverse pitch setting of said blades.

Y 5. In a variable pitch propeller mechanism, a

hub structure for mounting a plurality of propeller blades for rotary movement about their longitudinal axes, a hydraulic unitconnecting said blades to render them simultaneously movable, a plurality of movable and stationary abutments in said hydraulic unit, fluid pressure means for eflecting displacement of said abutments comprising a plurality of fluid pressure cylinders connected to a. source 01' oil supply and oil return passage in the engine shaft, and having pistons for boosting the pressure in said passages, flow passages leading from said cylinder to the hydraulic unit and manual control means for controlling the pressure in said passages.

6. In a variable pitch propeller mechanism, a hub structure for mounting a plurality of propeller blades for rotary movement about their 5 longitudinal axes, gear wheels mounted on said blades, a gear wheel interacting with'the teeth of the wheels on said blades to render them simultaneously operative, an hydraulic unit embodying a plurality of stationary and. movable vabutments, the latter being joined totheintermeshing gear wheel to actuate the blades to vary their pitch setting, a source of fluid pressure for said unit, pump mechanism operative in response to rotary movement of said propeller mechanism for varying the pressure of the fluid for said unit, means for selectively applying fluid pressure to said unit to render it operative in opposite directions, and means independent of said last named means for regulating the fluid pressure of said pump mechanism.

'7. In a variable pitch propeller mechanism, a hub structure for mounting a plurality of propeller blades for rotary movement about their longitudinal axes, operating mechanism for 51- multaneously subjecting said blades to angular allel blades for angular movement about their longitudinal axes, hydraulicdisplacement means for simultaneously subjecting the blades to variable pitch setting, said hydraulic displacement means being connected to employ the lubricating 40 fluid of the drivemotonpump mechanism for circulating the lubricating fluid and for boostingthe pressure of said fluid in its application to saidhydraulic displacement means, and control means for regulating the fluid pressure delivered by said pump .9. In a variable pitch propeller mechanism, a hub structure for mounting a plurality of propeller blades for rotary movement about their longitudinal axes, hydraulic displacement means 60 I for simultaneously subjecting the blades to variable pitch setting, a source of fluid pressure for said displacementmeans, means for selectively applying fluid pressure to said displacement means to render same operative in opposite directions, pump mechanism for circulating the pressure fluid and for boosting the pressure or the fluid in its application to said hydraulic displacement means, said pump mechanism being operative in response to rotary movement of said pro- 6 peller mechanism, and control means for regulating the fluid pressure delivered by said pump.

WALTER. s. noovna.

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