US1914754A

US1914754A - Variable pitch propeller

Info

Publication number: US1914754A
Application number: US550011A
Authority: US
Inventors: Max M Munk
Original assignee: Individual
Current assignee: Individual
Priority date: 1931-07-10
Filing date: 1931-07-10
Publication date: 1933-06-20
Anticipated expiration: 1950-06-20

Description

Jam 20, 1933. M. M. MUNK 1,914,754

VARIABLE PITCH P-ROPELLER Filed July 10, 1931 Patented June 20, 1933 M'AX M. MUNK, OF WASHINGTON, DISTRICT OF COLUMBIA VARIABLE PITCH PROPELLER I Application filed July 10,

very large centrifugal forces and the constructions so far proposed have their bearing surfaces loaded by the centrifugal forces. As a result, excessive friction is developed between the moving parts and it is necessary to use a large force in order to adjust the propellers.

Itis an object of the present invention to provide a propeller which is adjustable during operation, all bearing surfaces of which are free from centrifugal forces.

Another objectof this invention is to provide a propeller having longitudinally split blades, corresponding pairs of blade portions forming individual units balanced by themselves.

Still another object of this invention is to provide a propeller consisting of portions 7 adjustable relative to each other by rotation 35 about the main propeller axis.

With these and other objects in view. which may be incident to my improvements, the invention consists in the parts andcombinations to be hereinafter set forth and claimed.

g with the understanding that the several necessary elements, comprising my invention, may be varied in construction, proportions and arrangement, without departing from the spirit and scope of the appended claims.

,6 In order to make my invention more clearly understood, I have shown in the accompanying drawing means for carrying the same into practical effect, without limiting the improvements in their useful applica- 50 tions to the particular constructions, which 1931. Serial No. 550,011.

for the purpose of explanation, have been made the subject of illustration.

In the drawing like numerals refer to similar parts throughout the several views, of which 55 Fig. 1 represents a cross section through the center of a propeller along the main propeller axis and a pair of blades;

Fig. 2 shows a cross section through line 2-2 of Fig. 1, and F 1g. 3 is a cross sectional view through the propeller along the line 33 of Fig. 1.

Referring to the drawing, and more particularly to Fig. 1 thereof, the main body of the propeller is shown as being split or di- 6 vided into two portions, 1 and 2. The front portion 1 is keyed to the driving shaft 3 and secured thereto by means of a washer 4. and lock nut 5 which presses the front portion of the propeller against the collar 6 of the shaft 3. The propeller portion, 1, consists of the hub 1a, the blade portions 15 and 10, all three parts being formed integrally of light metal.

On the rear extension of the hub 1a is rotatably mounted the hub 2a of the propeller portion 2, which hub is formed integrally with the two blades portions 2?) and 20. A ring 7, fastened to the hub 1w by means of pins 8, prevents any axial motion between the propeller portions 1 and 2. Between the two rear extensions of the hubs 1a and 2a is inserted a bearing or flanged sleeve 9 interlocking with the extensions 1a and 2a by means of spiral keys 9a and 9b fitting into corresponding spiral grooves of the hub extensions. The spirals 9a are right handed and the spiral keys 9b are left handed. All parts so far mentioned rotate with the propeller and its shaft.

The flange of the sleeve 9 is held in axial position by a nut 10 which may be screwed along the outside thread of the bearing 11 by means of a hand crank 12, the shaft 13 and the cog wheel 14 in mesh with the nut 10. The ring 15 attached to the nut 10 by means of bolts, 16, eliminates any axial motion between the nut 10 and the sleeve 9,

without interfering with the rotation of the 109 sleeve relative to the stationary nut when the hand crank 12 is turned.

In order to increase the rigidity of the propeller, the two adjacent parts of the blade may be dovetailed as shown at 16. I

When the hand crank is turned the nut 10 is rotated and moves along the sleeve 9 in an axial direction and in consequence of the opposite inclination of the spiral keys of the bearing the parts 1 and 2 of the propeller turn through a small angle relative to each other and adjustment is thereby effected.

The cross section of the propeller shown in Fig. 3 through the two portions of the blade shows the effect of the adjustment on the common cross section. The dotted section of one blade portion is moved to the fullline position whereby the aerodynamic pitch and the effective blade area is changed.

It will now be realized that there has been disclosed a principle relating to the changing of pitch of a propeller, which can be effected without experiencing difiiculties resulting from large bearing pressures caused by centrifugal forces.

While I have shown and described the pre-- ferred embodiment of my invention, I wish it to be understood that I do not confine myself to the precise details of construction herein set forth, by way of illustrations, as it is apparent that many changes and variations may be made therein, by those skilled in the art, without departing from the spirit of the invention, or exceeding the scope of the appended claims.

What is claimed is:

1. A propeller comprising a blade divided longitudinally into two parts, one of said parts being movable with respect to the other about the axis of the propeller shaft.

2. A propeller comprisinga blade having a plurality of sections, one section of the blade being adapted to slide relative to another section about the propeller axis.

3. A propeller blade consisting of two sections adapted to slide relative to each other about the main propeller axis.

4. A propeller comprising a blade having two sections formed with hub extensions, a

' bearing mounted between the extensions and means adapted to impart motion to said bearing whereby the propeller blade sections slide relative to each other about the main propeller axis.

5. A propeller comprising a blade having two sections formed with integral hub extensions, a bearing mounted between the extensions and interlocked therewith, and means adapted to impart motion to said bearing whereby the propeller blade sections are rotated relative to each other about the axis of the propeller shaft.

6. A propeller comprising a blade having two sections formed with integral hub extensions having grooves formed therein, a bearing mounted between said extensions and interlocked therewith, and means adapted to impart longitudinal movement to said hearing whereby the propeller blade sections are rotated relative to each other about the axis of the propeller shaft.

- 7. A propeller comprising a blade having two sections formed with integral hub extensions, said extensions having grooves formed therein, a bearing mounted between the extensions, means to interlock the bearing with the hub extensions comprising keys adapted to fit into the grooves formed in the hub extensions, and means adapted to impart motion to said bearing whereby the propeller blade sections are rotated relative to each other about the axis of the propeller shaft.

8. A propeller comprising a blade having two interlocked sections formed with integral hub extensions, said extensions having spiral grooves formed therein, a bearing mounted between the extensions, means to interlock the bearing with the hub extension comprising spiral keys adapted to fit into the spiral grooves formed in the hub extensions, and means adapted to impart longitudinal and rotary motion to said bearing whereby the propeller blade sections are rotated relative to each other about the axis of the propeller shaft.

- In testimony whereof I ailix my signature.

- MAX M. MUNK.