US1980272A

US1980272A - Propeller

Info

Publication number: US1980272A
Application number: US511584A
Authority: US
Inventors: Clinton H Havill; Mansson Martin
Original assignee: Eclipse Aviation Corp
Current assignee: Eclipse Aviation Corp
Priority date: 1931-01-27
Filing date: 1931-01-27
Publication date: 1934-11-13
Anticipated expiration: 1951-11-13

Description

NOV. 13, 1.934,. Q HAV| 1 L Er AL 1,980,272

' PROPELLER Filed Jan. 27 1951 2 Sheets-Sheet l .R )Ll NvENTg? BY ATTORNEY PROPELLER Filed Jan. 27, 1931 2 sheets-sheet 2 ATTORNEY Patented Nov. 13, 1934 UNITED STATES PATENT OFFICE PROPELLER Clinton HQ Havill, South Orange, and Martin Mansson, East Orange, N. J., assignors to Eclipse Aviation Corporation,

East Orange,

10 Claims.

' This invention relates to propellers and more particularly to propellers wherein the pitch of the blades may be varied during operation.

One of the objects of the present invention is to provide a propeller embodying novel mechanism for varying the pitch or angularity of the blades while the propeller is rotated.

Another object of the invention is to provide a novel pitch-changing rmechanism for a propeller which is automatically operable, thus dlspensing with the necessity of any manual control or adjustments.

Still another object is to provide in a variable pitch propeller, novel means for varying the pitch of the blades in accordance with the driving torque of the means or mechanism employed for rotating the propeller.

A further object is to provide in a propeller of the variable pitch type, novel means responsive to centrifugal force for neutralizing the torsion on the propeller blades and which cooperates with the pitch-changing mechanism for securing an efficient blade operating angle during operation.

A still further object is to provide in a propeller, novel means automatically movable axially of the driving shaft for varying the pitch of the blades in accordance with the driving torque of the shaft, together with centrifugally-responsive means for substantially offsetting the tendency of the blades to assume a zero-pitch condition due to torsion.

The above and further objects of the invention will appear more fully hereinafter from the following detailed description when taken in connection with the accompanying drawings. It is to be expressly understood, however, that the drawings are for purposes of illustration only, and arenot designed as a definition of the limits of the invention, reference being had for this purpose to the appended claims.

In the drawings, wherein similar reference characters refer to like parts throughout the several viewsz- Fig. 1 is a horizontal partial sectional view of a propeller embodying the present invention;

Fig. 2 is an end view of the propeller, partly in section;

Fig. 3 is a side View, partly in section, taken on lines 3 3 of Fig. 2; and

Fig. 4 is afragmentary view in section of a portion of the propeller illustrated in Fig. 2.

Referring now to the drawings and more particularly Figs. 1 and 2 thereof, a propeller embodying the principles of the present invention is disclosed therein as comprising a plurality o f l propeller blades 6, a portion only of the blades being shown, in order to employ a large scale drawing. The blades are adapted to be rotated by a rotatable driving shaft '7, which may be an engine crankshaft or extension thereof, and the pitch of the blades is automatically adjustable in accordance with the driving torque of the driving means '7, in a manner Which will appear more fully hereinafter.

In order to drivably connect the propeller blades 6 to the driving shaft 7, there is provided a main hub forging 8 having a plurality of axially aligned sleeves or sockets 9, adapted to rotatably receive the root ends ofthe blades. As shown, a driving block l0 is interposed between the hub and driving shaft-secured thereto as by means of keys 11, and maintained in proper relation with respect to the shaft by means of split front and rear cones l2 and 13 respectively, which are adapted to be brought into firm engagement with said block by the provision of a threaded member or nut 14, threadedly received bythe outer eX- tremity of the driving shaft.

Preferably, the hub 8 is drivably connected to the driving block and shaft so as to be axially movable in response to the driving torque of the latter and in the form shown, such drivable connection is effected by any suitable means such as aplurality of helically or spirally arranged ball bearings l0a which are interposed between the block and hub and are effective during torque-responsive movement of the shaft, to im-A part a longitudinal movement to the hub with respect to the shaft.

Means are provided for varying the pitch of the blades during such torque-responsive movement of the hub, and preferably such means are constituted by cooperating members carried respectively by the driving block and the root ends of the blades. As shown, such means include a pair of relatively stationary rack members 15, Fig. 3, xedly secured to laterally extending ears 16, Fig. 2, formed integrally with a plate 17, the latter being rotatably mounted on the driving block 10 and maintained in proper relation with respect thereto by means of a nut 17a. Suitable thrust bearings 1'7b are interposed between memf bers 17 and 17a in order to permit relative movement therebetween. Each of the racks is adapted to mesh with a ring gear 18, Fig. 2, secured, in any suitable manner, to the root end of each blade so that during relative movement between the hub and the driving shaft, these gears will locked thereto.

travel along the racks 15 and effect a change in the pitch of each propeller blade.

In order to rotatably secure each blade in its respective socket, a split sleeve 19 encircling the blade root end and secured thereon as by means of the ring gear 18, is provided, and these parts are firmly maintained in proper position within the hub Asocket 9 by a member 20 threadedly received by the outer portion of the socket and suitably Interposed between the sleeve 19 and member I20, a ball thrust bearing 21 is provided, and a suitable roller bearing 22 is confined between the inner portion of the hub socket and the ring gear 18 in order to permit eflicient and substantially frictionless rotation of the latter with respect to the former.

Preferably, means are provided for yieldably resisting axial movement of the hub with respect to the shaft, and in the form shown such means are constituted by a plurality of resilient members such as springs 23, which may be interposed between the plate 17 and the propeller hub. It will be apparent that the tension of springs 23 lis normally effective to maintain the hub in\such position relative to the driving shaft, that the pitch of the blades will be a maximum, as indicated by the blade section 6a in dotted lines, Fig. 3, but vthat during operation, the hub will be moved upwardly, as viewed in said figure, in response to the thrustof the propeller blades to compress the springs 23, the cooperation between 'the ring gear 18 and rack 15 being operable during such movement to decrease the pitch of the blades. It is to be understood that the inclination or helical angle of the spiral ball races 10 is such that the propeller hub vwill tend to move downwardly, Fig'. 3, in response to 4the driving torque of the engine shaft, to increase the pitch of the blades, which movement opposes the above-described thrust-responsive movement of the hub. Preferably, the springs 23 are adjusted in such a manner as to be effective, during operation of the propeller, to arrest V the above-described Imovement of the hub in such a positionthat the resultant pitch will be substantially proportional to the driving torque of the drive shaft 7. y

Means is provided for substantially neutralizing or compensating for the torsion of -each of the propeller blades and preferably, this 'means is responsive to centrifugal force. .In the form of the invention illustrated, such means is/constituted by counter-weighted gear segments 24 adapted to cooperate with each respective ring gear 18 in such a manner as to tend to increase. the pitch of the blades, during rotation of the propeller, thus opposing the effect'of torsion which normally tends to decrease the pitch of the blades. Referring moreparticularly to Figs. 3 and 4, each counter-weighted gear. segment 24 is pivotally connected by a pin 25 lto a member y26, 'xedly secured to the hub socket 9 as bymeans of screws 27. -Each hub socket is provided with a suitable slot in order to permit engagement between the segment 24 and the ring gear 18.

It 'will be apparent from the above that when the propeller is not in operation, the resilient members 23 will be effective to maintainthe hub in the position shown in Fi'g. 1 wherein the pitch of each blade is amaximum. As soonas the driving means 7 is rotated in the desired direction, l however, the hub will tend to be moved upwardly,

as viewed in Fig. 1, in response to thrust, and downwardly by reason of the screw-threaded 'action of the helically arranged bearings lOinterposed between the driving shaft and the hub, and the extent of movement of the latter, as

heretofore pointed out, will be-substantially pro- Y y portional to the driving torque imparted to the vpropeller by the shaft 7. During such movement,

the pitch of each blade will be automatically 'varied because of the cooperation between the gear and

rack members

18 and 15 respectively.

In the above described operation and considering that the propeller utilized is of the tractor type and normally rotating counterclockwise, as viewed from the front in Fig. 1, the spiral ball .races l0a are arranged similarly to a right-hand sponsive movement to the hub to produce the desired change in pitch.

It is also to be pointed outl that the counterweighted gear segments 24 constitutecentrifugally-responsive means which tend to increase the pitch of the blades and which oppose the effects of torsion which tends to turn the blades into a zero-pitch condition. Referring to Fig. 3, when shaft 'l is rotated in a counter clockwise direction as viewed from the front, the segment 24 will tend to rotate in a clockwisedirection about the pivot 25, thus cooperating through gear 18 withv the stationary rack 15 and tending to force the hub downwardly, as viewed in this figure, wherein the pitch of the blades will be a maximum.

There is thus provided by the present invention a novel propeller of the variable-pitch type,

wherein the pitch of the blades is automatically controlled i'n accordancewith the driving torque of the means for .rotating the propeller. The inclusion of the centrifugally-responsive means cooperating with the pitch-changing mechanism in/ driving means and the hub,'an unusually efficient and substantially frictionless arrangement is secured for automatically moving said hub axially of the driving means in response to the torque of the latten While there has been shown and described only one form of the invention, it is to be expressly understood that the same is not limited thereto but may be embodied in various mechanical forms in order to permit the use of a tractor or pusher vtype of propeller or to impart torque-responsive movement to the hub in order to produce the desired change in pitch during operation.

Various changes may also be made in the reladat tive sizes, shapes and arrangement of the various component parts of the invention without departing from the spirit thereof, as will lnow be apparent to those skilled in the art. Reference will therefore be had to the appended claims for a definitionof the limits of the invention.

What is claimed is: A

1. An. aircraft propeller, comprising a plurality of blades, driving means therefor, means responsive to the driving torqueof said rst-named means for varying the pitch of saidv blades, said for yieldingly cooperating with said torque-re-WLS( sponsive means, and means to compensate for the torsion of the blades.

2. A propeller having a plurality of blades, a hub for receiving said blades, means for rotating said hub, means responsive to the driving torque of said rotating means for moving said hub and blades relatively to said rotating means, means for automatically varying the pitch of said blades during such movement of the hub and blades, and centrifugally-responsive means tending to oppose torsion of the blades due to centrifugal force.

3. In a propeller for aircraft having a plurality of blades, means for rotating said blades, means responsive to variations in the driving torque of said rotating means and including a gear and rack mechanism for changing the pitch of said blades, and means responsive to centrifugal force for neutralizing the torsion of said rotating blades.

4. An aircraft propeller having a plurality of blades, means for rotating said blades, means responsive to variations in the driving torque of said rotating means tending to increase the pitch of said blades, and means responsive to centrifugal force tending to increase the pitch of said blades.

5. In combination, a. rotatable shaft, a plurality of propeller blades adapted to be rotated by said shaft, means responsive to variations in the driving torque of said shaft for increasing the pitch of said blades, yieldable means Vcooperating with said torque-responsive means, and means responsive to centrifugal force tending to increase the pitch of said blades.

6. A propeller comprising a plurality of pitchvariable blades, a hub therefor, means for rotating said hub, resilient means for normally maintaining the pitch of said blades at a maximum, and a helical driving connection between the hub and rotating means whereby said hub is relatively angularly movable with respect to said rotating means in response to the torque of the latter and tending to increase the pitch of said blades in opposition to the thrust of the blades tending to decrease the pitch of the latter.

'7. In a propeller having a plurality of blades, means for rotating said blades, means for automatically varying the pitch of the blades during operation, and. means including centrifugallyoperable counter-weighted gear members cooperating with said pitch-varying means for substantially overcoming the torsion of said blades.

8. In a variable pitch propeller, a hub, a plurality of propeller blades rotatably carried by said hub, an engine driven shaft for rotating the hub,

means responsive to the torque of said shaft for.

moving the hub in one direction with respect to the shaft, means responsive to the thrust of the propeller blades for moving said hubl in another direction with respect to the shaft, and means operated by a movement of the hub'in either direction to vary the pitch of the blades.

9. In a Variable pitch propeller having a pair of axially aligned sockets, a hub, a propeller blade rotatably mounted in each socket, a rotatable power shaft, a helical driving connection between said hub and shaft, said hub being movable relative to the shaft in response to the driving torque of the latter, means interposed between said shaft and said hub'and arranged forwardly of the latter for yieldingly opposing movement of the hub in one direction relative to the shaft, and means including elements carried by said shaft and blades respectively for varying the pitch of the latter during torque-responsive movement of the hub relative to the shaft, said shaft carried elements extending into said hub sockets.

10. In a variable pitch propeller having a hub, a plurality of blades rotatably carried by said hub, a rotatable shaft, means for drivably connecting said shaft and hub, said hub being movable relatively to said shaft in accordance with the thrust of said blades and the torque of said shaft, means interconnected between the shaft and blades for varying the pitch of the latter during such relative movement of the hub with .respect to the shaft, and weighted members cooperating with each of said blades and responsive to centrifugal force for substantially neutralizing the effects of torsion on said blades.

CLINTON H. HAV'ILL. MARTIN MANSSON.