US3109498A - Controllable pitch propeller - Google Patents

Description

Nov. 5, 1963 H. BLOUNT 3,109,498

CONTROLLABLE PITCH PROPELLER Filed Jan. 12, 1962 3 Sheets-Sheet l INVENTOR.

LUTHER H. BLOUNT BY 6224401 i @144 ATTORNEYS Nov. 5, 1963 1.. H. BLOUNT 3,109,498

CONTROLLABLE PITCH PROPELLER Filed Jan. 12, 1962 3 Sheets-Sheet 2 F (5 5 INVENTOR.

LUTHER H. BLOUNT BY FIG. 4 flmmw ATTORNEYS 1963 L. H. BLOUNT 3,109,498

CQNTROLLABLE PITCH PROPELLER Filed Jan. 12, 1962 3 Sheets-Sheet 3 BLADE CENTER C III! 3/ 38/1 REVERSE Ill FEATHER) 3/ I I l/ I,

MID AHEAD A MAX. THRQW PLUNGER 37/ 7 37, ail 37,,

INVENTOR.

LUTHER H. BLOUNT BY AW ATTORNEYS United States Patent Office lh g/lfl Patented Nov. 5, 1963 3,199,498 (ZGNTRQLLABLE llT CH PRGEELLER Luther H. Blount, Warren, RI. (Poppasquash Road, Bristol, RI.) Filed Jan. 12, 1962, Ser. No. 165,748 4 Qlainrs. (Cl. fill-160.46)

This invention relates to a controllable pitch propeller.

In a controllable pitch propeller the blades are rotatably mounted in the hub of the propeller and some means is provided which moves axially of the drive shaft and axially of the propeller hub so as to rotate the blades relative to the hub. Various means are utilized for this purpose.

One of the objects of the invention is to provide a mechanical connecting means between the rotatable blades and the part which moves axially of the drive shaft and propeller hub so that the power applied may be more advantageously utilized in the shifting of the blades.

Another object of this invention is to provide an arrangement which, while providing the advantageous arrangement of utilizing a maximum of the power applied for rotation of the blades, also provides for a movement of the blades angularly about their axes to such an extent that movement may occur from the position of reverse through neutral and ahead to that of full feathering.

A further object is to utilize a blade and its spindle which may be cast in a single piece and the spindle machined to shape and size.

With these and other objects in view, the invention consists of certain novel features of construction as will be more fully described and particularly pointed out in the appended claims.

in the accompanying drawings:

FIGURE 1 is a perspective view of the propeller showing a fragmental portion of the drive shaft and the control rod;

FIGURE 2 is a top plan view of the propeller of FIG- URE 1 with the blades located in feathering position;

FIGURE 3 is a sectional view taken in the plane of the axes of the blades looking rearwardly;

FIGURE 4 is a sectional view looking down from above on the hub with portions broken away for clarity and illustrating one of the blades as in feathering position with the blade actuating plunger at one end of the its stroke;

FIGURE 5 is a view similar to FIGURE 4 but illustrating the plunger as moved to substantially the other end of its stroke and the blade shown as in reverse position, the drive shaft being of left-hand rotation;

FIGURE 6 is a perspective view of the plunger and its linkage connection to the spindle of one of the blades; and

FIGURE 7 is a diagrammatic view illustrating the various positions of the lever and linkage mechanism and showing the corresponding position of the blade with reference thereto.

In proceeding with this invention, I have provided a hub having an axially extending cylindrical cavity in which a generally cylindrical plunger is slidably guided. A rod extends forwardly from the plunger out of the hub and through the drive shaft for actuation of the plunger axial- 1y of the hub and drive shaft. A plurality of propeller blades are rotatably mounted in the hub. The axes of these blades are in a plane at right angles to the axis of the hub and propeller shaft, and the axis of each blade is offset to one side of but parallel to a radius from the axis of the hub sufficiently to position the axis at one side of the cylindrical cavity in the hub. The bearing for the spindle of the blade is formed of a size so that it intersects the cylindrical cavity of the hub, and a lever arm extending from the spindle of the blade extends into the hub cavity and is t ere connected by means of a link to the plunger in the cavity, thus providing a long leverage arm from the axis of the blades for multiplying the force and distance of stroke which is applied through the rod and plunger to rotate the blades.

The hub is circular in a plane at right angles to the shaft axis and is also arcuate in form in a plane passing through the shaft and hub axes. The trailing edge of the blade is curved on its edge nearest the hub so as to follow the curvature of the hub and by reason of the hub being curved in two different planes, this blade may swing so as to follow this curvature rather closely.

With reference to the drawings, li'i designates the drive shaft from a vessel. This drive shaft is hollow with a rod 11 extending therethrough. A hub 12 is secured on the outboard end of the drive shaft and is cylindrical in cross section at right angles to the axis of the drive shaft and is also arcuate as at 13 in any plane which passes through it and includes the axis of the hub. The blades designated generally 14 comprise blades proper 15 and spindles 16 extending therefrom. These spindles are rotatably mounted in bosses 17 projecting outwardly from the generally curved surface of the hub 12 as can well be seen in the section taken in FIGURE 3 extending through these bosses. The edge 13 of each blade is curved to follow closely the curved surface of the hub 12 in a plane at right angles to the shaft axis and which will also follow the longitudinally arcuate form of the hub as shown at 13. This permits of a wide angle range of swinging of the blade Without contacting the surface of the hub.

Each of the bosses are bored to provide a bearing 20 for the spindle in of the blade, and this spindle is recessed as at 22 to receive an O-ring 21 so as to seal this spindle in its bearing and prevent the entry of sea water into the hub. The spindle is also recessed as at 23 so as to receive a projection 24 from the bearing 20 so as to lock the blade in position. The lower end 29 of the spindle 16 is received in a reduced portion 30 of the bearing. The hub is formed in three sections 25, 26 and 27 (see FIGURES 4 and 5). The sections 25 and 26 separate along a plane passing through the axes of the spindles 16 for the assembly of the spindles in the bearings 20. These three sections are held together by bolts 28 passing through sections 27 and 26 and threaded into section 25 as may be seen in FIGURE 2.

Extending radially from each of the blade spindles, there is a lever arm 31 (see FIGURES 3, 4, 5 and 6) which is bifurcated as seen in FIGURES 3 and 6. A plunger 32 is generally or pseudo cylindrical and presents surfaces on the arc of a cylinder and is slidably guided in the cylindrical cavity 33 of the hub and keyed against rotation as at 32'. The cylindrical surface of this plunger is cut away in three locations so as to provide essentially three rails 34 which are slotted as at 35 so as to open on opposite sides, and a link 36 is located in each of these slots and pivotally held therein by means of a pin 37 extending across the slot. The other end of this link is pivoted as at 38 in the lever arm 31. The rod 11 is secured to and extends from this plunger 32, by means of which the plunger may be moved axially of the drive shaft and the hub by any convenient means, such for instance as a hydraulic cylinder or some other means of actuation.

The blades l5 are shaped somewhat so that they do not lie in a single plane but they do extend generally in a single plane which is located at an angle to the radial projection of the lever arm 31 from the blade axis.

1 term the feathering position of the blades as a position in which the general plane of the blades extends parallel to a plane which would pass through the axis of the shaft and hub such as shown in FIGURE 4. This is a position in which, when the drive shaft is not rotating, the blades will present the least drag to being drawn through water in the direction of the axis of the drive shaft and is a position which would be assumed when a sailing vessel equipped with this propeller were being propelled by sail alone and without power. This position indicates substantially the full throw of the plunger 32 rearwardly into the hub 12 or into the cap portion 27 thereof. If this plunger is drawn forwardly by the rod 11, it will be apparent that the blade 15 as seen in Pl URE 4 will be angled by its leading edge 40 moving to the left and its trailing edge 41 moving to the right as seen in FIGURE 4, which will be the position for driving the vessel forwardly assuming a shaft to be rotating left-handed or counter clockwise as shown in ElGURE 1. As the plunger is drawn further forwardly, at some point the blade v15 will be in a plane substantially at right angles to the axis of the shaft which is referred to as a neutral position and in this position rotation of the shaft will not drive the vessel either forwardly or rearwardiy but the propeller will rotate without affecting movement of the vessel forwardly or rearwardly, thus giving no drive either forwardly or rearwardly from its rotation. Further movement of the rod 11 inboard'and advancing of the plunger 32 will cause the blade 15 to move into a position for causing rearward motion of the vessel, and the extreme rearward position of the blade is shown in FIGURE 5 e where it will be noted that the link 36 is at substantially.

right angles 'to the lever arm 31 which is the maximum position that may be had by the angular arrangement here shown.

Referring to FIGURE 7 which is diagrammatic, several different positions of the lever arm 3-1 and the link 36 are illustrated together with the position of the blade 1:5. In the feathering position in this diagrammatic figure, a single prime is added to the designating number, thus the lever arm is designated as 31 and the link as 36'. The corresponding position of the blade is designated as The pivot point for the link to the plunger is designated as 37' and the pivot point for the link to the lever arm is designated as 38'. A second assumed position of EEG- URE 7 shows the blade in the forward driving position about midway between feather and neutral, which will be the most'used position for driving the vessel, and in this case the numerals carry a double prime, the lever ,arm is designated as 31", the link as 36", the position of the blade as 15", the position of one pivot of link 36 as 37 and the position of the pivot of the other end of this link as 3 8". A third position as assumed which is that of the blade in neutral position. Here the numerals carry a triple prime; the blade is designated as 15", the lever arm as 31", the link as 36", the pivots of this link as 37" and 38". A fourth position is assumed which is that of maximum reverse in which the numerals carry four primes. The blade is indicated at 15, the lever arm as 31", the link as 36"" and the pivots of the link as 37"" and 38".

From this diagrammatic view, it will be observed that the more important positions of the lever arm which is about the mid-ahead position is a position in which the lever arm '31 or as shown in the diagrammatic view 3 1 is in a position to receive an almost maximum thrust in the direction of movement of the plunger along line 39 as the pivot 38 through which force is applied is the maximum distance from the axis of the blade spindle in. Thus in this position of the blade which results in maximum hydraulic force due to axial thrust of the turning propeller, the lever arm and link are in such relation that a resistance to this thrust is provided at the most advantageous location of the swinging lever arm, and by reason of the axis of the blade being off center from the line of the plunger, a long lever arm 31 or 31" as shown in the diagrammatic view is provided which is of marked advantage and a material improvement over the mechanical to the blades which has heretofore been had. The offset of the axis of the blade spindle thus is a material advantage in the application of power thereto in this type of a mechanism with the linkage operation which has been provided.

It will be readily observed that by varying the angle whichthe blade is positioned relative to the lever arm, certain variations of this diagrammatic view may be had and the position of greatest advantage for the lever arm with reference to the angle of the blade may be selected to be about the location of most use. advantage makes for easier movement of the blades in the astern positions, and also in the ahead positions to a someably mounted in said hub with their axes in a plane at right angles to the axis of the hub and each blade axis being ofiset to one side of but parallel toa radius from I said hub axis, each blade carrying within the hub a lever arm projecting from the blade axis, a link pivoted to said arm and to said plunger, said blade being generally in a plane at an angle to the projection of said lever arm, substantially said lever arm being in a line parallel to the line of movement of said plunger when said blade is in reverse pitch position and said link being at substantially right angles thereto.

2. In a controllable pitch propeller as in claim 1 wherein the stroke of the plunger is of suificient extent for movement of the blade from a pitch position of parallel to a plane passing through the hub axis to beyond a neutral in plane at right angles to the hub axis to a reverse pitc 3. In a controllable pitch propeller as in claiml wherein the hub has a cylindrical cavity and the plunger is a p eudo cylinder presenting a portion of a cylindrical surface slidable therein, a rod secured to said plunger and extending from said hub for actuation of the plunger.

4. In a controllable pitch propeller as in claim 1 wherein the hub has a cylindrical cavity and the plunger is a pseudo cylinder presenting a portion of a cylindrical surface slidable therein, with slots to receive said links, a rod secured to said plunger and extending from said hub for actuation of the plunger.

References Cited in the file of this patent UNITED STATES PATENTS 1,656,019 Roberts Jan. 10, 1928 1,756,215 Schneider Apr. 29, 1930 1,816,730 Hardin July 28, 1931 2,354,465 Le Bert July 25, 1944 2,476,638 Stuart July 19, 1949 FOREIGN PATENTS 393,113 Germany Mar. 29, 1924 447,950 Great Britain May 28, 1936 509,417 Great Britain July 14, 1939 754,852 Great Britain Aug. 15, 1956 Thus this power

Claims (1)

1. IN A CONTROLLABLE PITCH PROPELLER, A HUB, A PLUNGER AXIALLY MOVABLE IN SAID HUB, A PLURALITY OF BLADES ROTATABLY MOUNTED IN SAID HUB WITH THEIR AXES IN A PLANE AT RIGHT ANGLES TO THE AXIS OF THE HUB AND EACH BLADE AXIS BEING OFFSET TO ONE SIDE OF BUT PARALLEL TO A RADIUS FROM SAID HUB AXIS, EACH BLADE CARRYING WITHIN THE HUB A LEVER ARM PROJECTING FROM THE BLADE AXIS, A LINK PIVOTED TO SAID

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