US1765091A - Automatic variable-pitch propeller blade for airplanes - Google Patents

Description

June 1'7, 1930. 1 MORRIS 1,765,991

AUTOMATIC VARIABLE PITCH PROPELLER BLADE. FOR AIRPLANES Filed March 11, 1929 INVENTOR.

A TTORNE Y.

Patented June 17, 1930 PATENT OFFICE* LoUIs Mon-ms',- or KANSAS CITY, mssonm AUTOMATIC VARIABLE-PITCH-*PROPELLER BLADE FOR AIRPLANES Applicationled March 11, 1929. Serial No. 346,033.' Y

My invention relates to automatic variable pitch propeller blades for airplanes, and the object of the invention is tovprovide propeller blades for airplanes having facility for automatically changing the pitch of the blades relative to the speed 'of themotor to thereby regulatethe resistance of the blades to the air pressure.

1' attain these objects and other advantages by means of the mechanism illustrated in the accompanying drawing in which- Figure 1 is a vvertical section of a propeller hub embodying my invention,. and .showing the means for changing the pitch angle of the propeller blades. Figure 2 is a front end view of the propeller hub, and showing the springs for regulating the propellerlblades, the blades being omitted. Figure 3 is a front end view of the propeller hub with the springs removed, and showing the lugs for limiting the rotation of the spring housing.

Figure 4 is a rear end view of the propeller hub in operativeposition.

Figure 5 is a plan view of the inner side of the spring housing member.

Similar numerals of reference refer to corresponding parts throughout lthe several views. n

Referring to the drawings, the numeral 1 designates the front portion of an airplane motor. On the motor shaft 2 is idly mountedl a circular hub 3 having circumferentially of the body of the hub oppositely disposed recessed gear pits 4 in which are rotatably mounted beveled gear wheels 5 having hubs 6 .to which are secured in any suitable manner propeller blades 7. Pit covers 8 are secured on the body of the hub and over the gear pits, thebody of the hub at these places being reduced toA a plane surface for seating the covers. The covers are secured in place by screws 9 which are extended -through the covers and penetrate V the body of the hub. The covers are provided with holes to receive the lowerportions'of the blades. A gear pit 1 0 is recessed in the front end of the hub and. in which is rotatably mounted a beveled gear wheel ,11 in mesh with the gear wheels 5. Said gear Wheel 11 has a central hub portion 12 which is united with a hub 13 of a Wheel 14. The motor shaft is extended longitudinally v throughthe gear Wheel 11, hub` portion 12,. 'and keyed into the hub 13 of the wheel 14. :v The wheel 11 has four spokes dividing its `5 peripheral margin into four sections or compartments 16 and adapted for receiving and housing four spiral springs 17. On. the ^frontl end of the hub 3 are four forwardly projecting lugs 18 and which are located in near relation to the peripheral edge ofthehub and upon radial lines, so that the lugs shall pro--4 ject respectively into the respective sections -V f of the wheel l provided for the reception of the springs V17 and therebylimit the rotation of lthe wheel 14. The Wheel 111 is keyed on themotor shaft by a key 19. A disk cover 2O is secured on the outer side of the wheel la' to protectthe springs 17. l

When the motor is driven the motor shaft rotates the wheel 14 and the spokes of the same act against the springs to compress the same against the lugs 18 thereby imparting motion in the same direction to the propeller hub proper. As the speed of the motor increases the air resistance to the propeller blades also increases and thereby the rotary movement of the hub properis retarded correspondingly and it being idly mounted on the motor-shaft greater compression 'of the springs is effected and a rotation of the gear wheels 5 by the movement ofthe gear wheel 11 results in decreasing the pitch angles of f the propeller blades. When the speed of the motor decreases theair resistance to thel propeller blades decreases and thereby allowing the springs to react sufficiently to cause the. gear wheel 11 to turn the gear wheels 5 on the propeller blades to effect anincrease in the pitch angles of the blades. lThe actions described are entirely automatic andare efective throughout the motor` speeds. The automatic variable pitch angle of the propeller' blades is anadvantage over the rigid propeller and eifects greater eiliciency in flying 95 an airplane. The lugs 18 on the end of the propeller hub also form seats for the one ehd of the springs 17 the opposite ends of the springs being seated on thefspoke divisions 15 of the wheel 14 which carry the springs. 100

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" .The motor shaft revolyes the wheel 14 and compresses the springs sufficiently to rotate the opeller hub. Said wheel functions very Propellers and, at-the same time, regulating the pitch angle of the propeller blades accord-A in to the air resistance against the same.

aving described the invention whatA I` blade for airplanes, the combination with the motor shaft, of a propeller hub mounted free on the shaft, a plurality 'of propeller blades journaled in said hub and having gear wheels on their inner ends, a vclutch'wheel mounted on the shaft and adapted to revolve said hub and having axially a gear wheel enmeshed with the gear wheels on, said blades, and comvpression springs carried by said clutch Wheel und engaging said propeller hub.

Dated Kansas City, Missouri, March l6th,

LOUIS MORRIS.

like a clutch in'starting rotation of the

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