US1494964A

US1494964A - Propeller

Info

Publication number: US1494964A
Application number: US297752A
Authority: US
Inventors: Hugh M Stoller
Original assignee: Western Electric Co Inc
Current assignee: AT&T Corp
Priority date: 1919-05-17
Filing date: 1919-05-17
Publication date: 1924-05-20
Anticipated expiration: 1941-05-20

Description

May 20, 1924. 1,494,964

1 H. M STOLLER PROPELLER Filed May 17. 1919 2 //1 van for:

Hug/2 /V., $f0//e/.'

Patented. May 20, 1924.

umrao s ArEs PATENT OFFICE.

HUGE KLSTOLLEB, OF NEW YORK, N. Y., ASSIGNOB TO WESTERN ELECTBTC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

PROPELLEB.

Application filed Kay 17,

To all whom it may concern:

Be it known that I, HUGH M. S'ropLnR, a citizen of the United States of America, re-

siding at New York in the county of New York, State of New'York, have invented certain new and useful Improvements in Propellers, of which the following is a full, clear, concise, andexact description.

This invention relates to pro ellers and has particular reference to a uid driven propeller which may be used to drive small electrical generators, or other similar pieces of apparatus.

Its object is the provision of a propeller in which, when. its speed of rotation exceeds a certain amount, an automatic and proportional change of the pitch, of the blades will be caused, and thereby restrict variations in its own speed under variations in the velocity of the driving fluid. The speed of operation of the apparatus towhich it is attached will thus be more regular than otherwise would be the case.

The invention comprises a propeller having any suitable number of arms, the general surfaces of which are inclined, as usual, both with respect to the longitudinal and trans: verse axes of the hub. The rear portion of each arm ,is relatively flexible and is at tached to the main body of the arm and clined rearwardly with respect to the vertical plane and the direction of rotation. When the driving fluid impinges upon the surface of the propeller arm it rotates, and this rotation results in the generation of considerable centrifugal force in the various parts of the arm. The centrifugal force generated in the flexible surface above mentioned, tends, due to the inclination of said surface, to bend the surface toward the vertical plane which would be in a direction tending to increase the pitch of the arm and check its speed, and thereby prevent a rise in the speed of rotation of the ropeller. In a referred form of the propeller, this flexib e portion is made of sheet metal havin considerable mass, so that the centrifuge force flgenerated .is suflicient to produce quite a de ection of the surface, and thereby more effectively control the speed of the propeller.

' This invention will be better understood by reference to the following detailed description taken in connection with the acccmpanying drawing, in which Fig. 1, rep- 1819. Serial N0. 297,752.

ance with this invention, Fig. 2 represents.

a side view of the same in which the position of the propeller for high wind velocities is shown in dotted lines, and Fig. 3 represents a top view of the propeller.

The invention is illustrated in Fig. 1 which is a perspective view of the device. As shown, the generator, or other apparatus to be driven, 1, is connected by a shaft 2 to a propeller having a hub 3 and arms 4 and 5. A greater number of arms can, of course, be provided if desired. From an inspection of the figure, the arms will be seen to be inclined with respect to the longitudinal axis of the hub 3, the direction of rotation of the propeller being indicated by an arrow. In accordance with this direction, the

edges

6 and 7, respectively, are the forward ed es of the arms, 4 and 5, and are formed y bending the metal of the arms back on itself and riveting the line of the overlapping portion as shown, and edges 8 and 9 are the rear edges of the arms a and 5. It will thus be seen that the

front portions

6 and 7 of each blade are very rigid and formed of two layers of metal and the rear portion 10 is relatively flexible being made of a single layer of material. The overlap is riveted along the edges by rivets 11 as shown.

The flexible ortion 10. is inclined as a whole. rearwar ly y from a vertical plane .and with respect to the direction of rotation, and thus will be considerably affected by the action of centrifugal force at high speeds. Since this portion 10 is preferably formed of some material having considerable mass, such as metal, when the propeller arms 4 and 5 have attained a certain s eed of rotation, the centrifugal force of t ese outer portions 12, corresponding to the well known law, F= will cause them to Fig. 2 illustrates a side view of the propeller of Fig. 1 looking at the propeller will tend to assume due to centrifugal force when the propeller is rotated at high speed.

\ It is apparent that this change in position of the portion 12 is due to centrifugal force, since the center of mass of portion 12 in moving into the plane shown in dotted lines, will move upwardly and rearwardly so that consequently the center of mass assumes a position farther away from the axis of rotation of the propeller. It will also be apparent from this figure, that when the propeller blade-tends to assume the position shown in dotted lines that more of the driving wind will 'be spilled thereby tending to reduce the speed of rotation of the propeller. i

Fig. 3 represents a top view of the pro peller of Fig. 1, and shows in full lines the position ofthe propeller blade at rest, while showing in dotted lines its position for a high speed of rotation.

This invention is particularly applicable to wind driven generators used on high speed vehicles, such as aeroplanes, which attain excessively high speed, a voltage regulation for the generators being provided by the use of this invention.

What is claimed is: 1. A wind driven propeller, comprising a hub, a propeller arm on said hub, the forward portion of said arm with respect to the direction of the wind being rigid, the rear portion of said arm comprising flexible material so joined to the rigid portion that when said propeller arm is at rest the flexible portion is bent forwardly in the direction of the wind and downwardly in the direction of the axis of rotation and such'that for high speeds of rotation the center of mass of the flexible portion will be moved rearwardly and farther away from the axis of rotation.

2, A wind driven propeller, comprising a hub, a metallic-propeller arm on said hub, the forward part of said pro eller arm with respect to the direction o the wind being of suflicient thickness to be rigid, the

thickened portion being of greater width near the hub than near the outer end of said arm, the rear portion of said propeller arm being composed of metallic material sufiioiently thin to be flexible, the rigid portion. and the flexible portion being so joined for the propeller arm at rest that the flexible portion is bent forwardly in the direction of the wind and downwardly in the direction of the axis of rotation and such that for high speedspf rotation the center of mass of the flexible portion will be moved rearwardly and farther away from the axis of rotation.

In witness whereof, I hereunto subscribe my name this 12th da of May A. D., 1919. HU- .H M. STOLLER.