US2484739A

US2484739A - Variable pitch propeller mechanism

Info

Publication number: US2484739A
Application number: US535084A
Authority: US
Inventors: Remmen Jorgen
Original assignee: Individual
Current assignee: Individual
Priority date: 1944-05-11
Filing date: 1944-05-11
Publication date: 1949-10-11
Anticipated expiration: 1966-10-11

Description

@ci. 111 1949., J. REMMEN VARIABLE PITCH PROPELLER MECHANISM Filed May ll, 19%

4 Sheets-Sheet l INVENTUR. g BY 7,14%

@cfi. M, 1949., J. REMMEN VARIABLE PITCH PROPELLER MECHANISM 4 Sheets-Sheet 2 Filed May 11, 1944 & m

Oct. 3]., 1949, J. REMMEN VARIABLE PITCH PROPELLER MECHANISM 4 Sheets-Sheet 3 Filed May ll, l9 44 INVENTOR 0a., M, 1949. J. REMMEN I 2,484,739

VARIABLE PITCH PROPELLER MECHANISM Filed May 11, 1944 4 Sheets-Sheet 4 3, 7 d INVENTOR.

By Wazgu oyad Patented Oct. 11, 1949 UNITED STATES PATENT OFFICE I 2,484,139 VARIABLE PITCH PROPELLER MECHANISM J orgenRemmen, Pittsburgh, Pa.

Application May 11, 1944, Serial No. 535,084

to constantly obtain a balanced thrust on the blades.

It is another object of the invention to provide a variable pitch propeller mechanism responsive to the twisting moment of the propeller blades which shall be of simple, compact and durable mechanical construction embodying a minimum number of wearing parts.

It is still another object of the invention to provide a variable pitch propeller mechanism in which the pitch adjustment is operative in response to the speed of rotation and the twisting moment of the blades, to maintain constant engine speed under all operating conditions.

Still a further object of the invention is the provision of a variable pitch propeller mechanism of the above-designated character in which the degree of pitch setting of the blades may be manually controlled.

Still a further object of the invention is the provision of variable pitch propeller mechanism of the above designated character for use in oppositely rotating propellers which shall have pitch adjusting means common to both propellers.

These and other objects of the invention will become more apparent from a consideration of the accompanying drawings constituting a. part hereof in which like reference characters designate like parts, and in which Fig. 1 is a top plan view, partially in section, of a propeller mechanism embodying the principles of this invention;

Fig. 2 a vertical section, partially in elevation, of the propeller structure of Fig. 1, Figs. 1 and 2 illustrating the bottom propeller of a pair of oppositely rotating propeller blades;

Fig. 3 a top plan view, partially in section, of the upper blade mechanism;

Fig. 4 a vertical cross-sectional view, partially in elevation, of the mechanism shown in Fig. 3;

Fig. 5 a side elevational view, partially in crosssection, of oppositely rotating variable pitch propeller mechanism and drive shafts therefor;

Fig. 6 a top plan view showing the cover plate in place;

Figs. 7, 8 and 9 are side elevations, partially in sections, and top plan views, respectively, of a modified form of variable pitch oppositely rotating propeller blades.

Cal

(Cl. I'm-160.42)

With reference to Figs. 1 to 6 inclusive of the drawings, the structure therein illustrated comprises a fixed or stationary housing I, Fig. 5, in which a hollow drive shaft 2 is journaled by

roller bearings

3 and 3a, the shaft 2 having a propeller hub I mounted thereon for rotation therewith. A second hollow shaft 5 is disposed within the hollow shaft 2 and is connected to a propeller hub which is mounted for rotation at the end thereof, shaft 5 being journaled in the hollow shaft 2 by roller bearings l and la. Shaft 2 is provided with a bevel gear 8 and shaft 5 with a bevel gear 9 which are driven by a pinion l0 connected to the engine shaft 6 l for driving the propeller hubs. A free-wheeling clutch l2 may be connected in the engine shaft to permit windmilling of the blades when the power is cut oif. Disposed within the hollow shaft 5 is a control rod 83 connected to a lever it fulcrumed at it and operated by a link it connected to a hand lever H for adjusting the pitch setting of the propeller blades, as will be hereinafter explained. A disconnecting clutch, not shown, may be provided in the engine shaft to permit operation of the motor without rotation of the blades.

The construction of the propeller blades and hubs is more clearly shown in Figs. 1 to 4 of the drawings which show a pair of propeller blade roots 98 mounted in sockets is having trunnions 20 disposed in bearings it of the hubs t and ii. The blade roots are pivotally mounted in the socket members by pins 22 and are restrained in their pivotal movement by leaf springs 23, the tension of which is regulated by ferrules 25. The blade sockets iii are free to pivot on the trunnions 2e and are restrained in their pivotal movement by leaf springs 25. The blade sockets are also rotatably mounted in journal bearings 26 of the trunnion members and thrust bearings 2'! are provided intermediate the trunnion bearing and gear segments 28. Bolts 29 extend through gear segments 28,bearings 21 and 26 and have threaded connection at 38 with the blade socket l9.

The gear segments 28 have gear teeth 3| which interact with the teeth of gear racks 32 mounted on levers 33 that rest against stops 34. The ends of the levers are provided with trunnions 35 that operate in the groove 36 of a slip ring 31 that is slidably mounted on the shaft 5 and connected by a cross pin 38 with the control rod l3, as shown in Figs. 1 and 2, the levers 33 of the upper blade member being pivotally mounted to trunnions 39 that are fixed to the end of the control rod l3, as shown in Figs. 3 and 4. When the control rod is moved vertically through the hand control 3 lever I! of Fig. 5, the positions of the gear racks 32 are correspondingly changed, which varies the degree of pitch of the blades as will be hereinafter explained. Pivot pins 22 are held against displacement by plates 22a which are fastened by screws 2212 as shown in Figs. 1 and 3.

The operation of the above-described mechanism is briefly as follows. The

hollow drive shafts

2 and 5 are rotated in opposite directions by the gear in of the propeller engine and the pitch of the propeller blades is at normal setting when lever i1 is in the position shown in Fig. 5. As the blades revolve the centrifugal moment on the air foil section of the blade will tend to pivot the blades on their trunnions 20. The pivotal movement will effect relative movement of the teeth of the gear segments 28 with the racks 32 causing angular adjustment of the blades to vary their pitch, thereby obtaining a balanced lift in both blades regardless of air currents where for example the propellers are employed on helicopter aircraft. If when employed as lifting propellers for helicopters the movement of the craft is in the direction of a head wind, the blade advancing into the wind will, because of the pivotal movement of the blade upward on its trunnions 20, be subjected to a decreasing pitch setting, while on the return movement of the blade in the slip stream it will drop to effect an increased pitch setting, thereby maintaining the propulsion force or thrust on both blades constant. By moving the control lever I1 and raising or lowering the control rod i3, the rack arms 33, which are pivoted on the trunnion bearings 2|, will effect a pitch change to increase or decrease the amount of pitch ad- Justment as the blades revolve. In case of engine failure the free-wheeling clutch i2 is connected to allow the blades to windmill as an Autogiro. The hand control is provided especially for regulating the degree of pitch adjustment in climbing to maintain maximum horsepower output of the motor which permits the employment of engines of smaller horsepower capacity on the one hand and allows for maximum climbing speed when larger horsepower engines are employed.

By means of the hand control of the pitch setting mechanism, the blades may be power driven for lowering the aircraft and the aircraft can be maintained at any desired elevation by merely adjusting the pitch setting by the manual control.

When the propeller mechanism is employed on aircraft of the wing type as a propulsion propeller, the pitch of the blades may be set by the control lever I! to obtain maximum horsepower output of the propeller engine for the take-oil. and adjusted for cruising to a pitch setting to maintain a constant engine speed. Because, as hereinbefore described, pivotal movement of the blade on its trunnion supports will effect a corresponding pitch setting, and further because such pivotal movement is induced by the twisting moment which is a factor of the propulsion force or load on the blade, the propellers will rotate at a constant speed for the particular pitch setting to which the manual control has been adjusted by lever II. The device thus operates as a constant speed propeller mechanism and constitutes a governor control for the propeller engine.

The pivoted joint 22 is employed on relatively long blades when used on helicopters to permit the blades to lag slightly when initially rotated. These pivotal connections may therefore be eliminated on propeller blades used in propulsion propeller mechanisms for the wing type aircraft.

Also in the latter use the springs 25 can be adiusted to tilt the blade forward when the motor is cut down to a landing speed, which would decrease thepitch setting of the blade.

In Figs. 7 to 9 inclusive is shown a modified form 01' helicopter variable pitch propeller mechanism in which the numeral 40 designates the stationary housing, ll the lower drive shaft and 42 the drive shaft for the upper blade. The control rod 43 is connected by a lever 44 to an adjusting mechanism operated by a hand wheel 45. The numeral 45 designates the hub for the lower blades and 41 the hub for the upper blades, the hubs being journaled by

roller bearings

48 and 49 on the shaft 4| and

bearings

50 and 5| on the upper drive shaft 42, the arrangement being such that the hubs may windmill in one direction of their rotation as when the engine stops. Shaft 4| is driven through bevel gear 52 and shaft 42 through bevel gear 53 by gear wheel 54 connected to the engine shaft 55. The blades 56 are mounted on the blade roots 5'! which extend through trunnion members 58 in which they are journaled. The ends of the blade roots 51 are provided with cranks 59, the crank pins 60 of which operate in grooves SI of slip rings 62 and 62a which are adjustable by the control rod 43 through the manipulation of the hand wheel 45. As will be apparent from Figs. 7 and 8 of the drawings, the lifting and lowering movement of the wings or blades 55 will cause rotation of the blades by virtue of their crank connections with the slip rings to effect pitch adjustment as they are revolving in the manner described in connection with the remaining figures of the drawings.

Although several embodiments of the invention and its uses have been herein illustrated and described, it will be evident to those skilled in the art'that'various modifications may be made in the details of construction without departing from the principles herein set forth'.

I claim:

1. In a variable pitch propeller mechanism, a hub structure, blade sockets having trunnion members mounted in said hub for movement in a plane transversely of the plane of rotation of the blade, blades mounted for rotary movement in said sockets, and segment gears mounted on the inner ends of the blades to be rotatable therewith, gear racks pivotally mounted on said trunnion members for interacting with said segment gears to vary the pitch of the blades in response to pivotal movement of the blade on the trunnion member, and manual means connected to said a gear racks for actuating the latter to adjust pitch setting of the blades independently of pivotal movement .of the blades on their trunnion supports.

2. In a variable pitch propeller mechanism, a hub structure, a plurality of blade sockets mounted on trunnions in said hub structure for receiving the blade roots therein to allow pivotal movement of the blades relative to said hub in a plane transversely .of the plane of rotation of the blade, blade members pivotally mounted on the blade roots to be movable in a plane opposite to the plane of pivotal movement of the socket members, springs mounted on the roots and on the blade sockets in the path of movement of the blades and sockets for limiting and restraining the relative movement of the blades and blade sockets, said blades having segment gears mounted on the inner ends thereof and gear racks pivotally mounted on said trunnion members having teeth interacting with the teeth of said segment 5 gears, said segment gears being mounted on levers pivotally mounted on the blade socket trunnions having arms for interacting with a slip ring, and

an adjustable slip ring for said arms whereby said racks may be actuated around their trunnion supports to subject the segment gears to rotary movement to vary the pitch of the blades independently of tilting'movement of the blades on their trunnion supports.

J ORGEN REMMEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED s'ra'res PATENTS Number Number