US1952066A

US1952066A - Propeller

Info

Publication number: US1952066A
Application number: US491528A
Authority: US
Inventors: Clinton H Havill
Original assignee: Eclipse Aviation Corp
Current assignee: Eclipse Aviation Corp
Priority date: 1930-10-27
Filing date: 1930-10-27
Publication date: 1934-03-27
Anticipated expiration: 1951-03-27
Also published as: FR725680A; GB388479A; DE645921C

Description

4March 27, 1934. c. H. HAvlLL l 1,952,066

PROPELLER Filed Oct. 27. 1930 3 Sheets-Sheet l C. H. HAVl-LL PROPELLER 3 Sheets--Sh'eei'l 2 z mm-i-m img Filed Oct. 27, 1930 C. H. HAVILL March 27, 1934.

PROPELLER Filed Oct. 27, 1930 3 Sheets-Sheet 3 Patented Mar. 27, 1934 i UNITED STATES PATENT OFFICE PROPELLER Application october 27, 1930, serial No. 491,528 14 claims. (01170-162) This invention relates to propellers and more particularly to variable pitch propellers.

One of the objects of the present invention is to provide in a variable pitch propeller, novel means employing the thrust of the blades for changing the angle of incidence or pitch of the latter during operation.

Another object of the invention is to provide a propeller wherein novel means disposed interiorly of the propeller hub construction are employed which are effective during operation of the propeller to automatically vary the pitch of the blades in such a manner that the propeller will operate at maximum efiiciency under substantially all conditions.

Still another object is to provide in a propel-ler of the above character and wherein means responsive to the thrust of the blades is utilized to secure a variation in the pitch of the blades, a novel construction and arrangement of the pitchvarying means whereby the twisting force due to torsion will have no eect in varying the angularity of the blades. Y Y A further object is to provide in a propeller having pitch-variable blades, a novel cam arrangement associated respectively with the propeller driving shaft and blades for changing the pitch of the latter during operation.

A- still further object is to provide in a propeller of the above character, a novel construction and arrangement of parts whereby an exceedingly efficient and compact structure is realized, light in weight and positive in operation.

'I'he above and other novel features ofthe invention will appear morefully 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 employed for purposes of illustration only and are not designed as a definition of the limits of the invention, reference being had for vthis purpose to the appended claims.

In the drawings wherein similar reference characters refer to similar parts through the several views;

Fig. 1 is a horizontal section of a propeller embodying the present invention;

Fig. 2 is a vertical section taken along line 2-2 of Fig. 13 i Fig. 3 is a side View, partly in section, of the propeller;

Figs. 4 and 5 are diagrammatic views illustrating the cam mechanism associated with each 55- blade; and

iti

Figs. 6 and 7 are perspective views illustrating the construction of the cam mechanism.

Referring to the drawings and more particularly to Figs. 1 and 2 thereof, a propeller illustrating the principles of the present invention is illustrated therein as comprising a plurality of propeller blades 8, a portion only of the latter being shown in order that a large scale drawinglmay be employed. The blades 8 are adapted to be driven by a rotatable driving shaft 9, which in the case of aircraft installations, may be a member drivably connected to the crankshaft of an internal combustion engine, and the pitch or angle of incidence of the blades is variable in response to the thrust thereof, as will be described more particularly hereinafter.

In order to drivably connect the blades 8 to the shaft 9, a splined driving block 10 encircling said shaft is employed, the said block being firmly secured in driving relation therewith as by means of split front and rear cones 11 and 12 respectively, which are adapted to be forced into firm engagement with suitable beveled faces formed on the block by a nut 13 threadedly received by the outer extremity of the driving shaft. Preferably, suitable locking means such as for example, lock pin 14 may be utilized for securely maintaining the hub 13 in position after assembly'. A main hub forging l5, drivably connected p to and surrounding the block 10 is provided for 8 supporting the propeller blades, and preferably these parts are so constructed that the hub forging is capable of axial movement with respect to the driving block, a plurality of bearings 16 being interposed between these two members in order to facilitate this movement.

The hub member 15 is preferably formed in such a manner as to rotatably support the root ends of the blades 8 to the end that the blades may be capable of rotation about their longitudinal axis in order to vary the angle of incidence or attack. In the form of the invention illustrated, the hub is provided with a pair of axially aligned sockets or sleeve 17 which are adapted to receive the root ends of the blades, the latter being provided with split root housings 18. Interposed between the root housing and the socket,

a plurality of ball bearings 19 are provided, and a suitable antifriction bearing, such as ball bearing 20, confined between a shoulder 21 formed 105 integrally with the housing 18 and a retaining nut 22, is provided to retain the blade in opera.- tive position despite the centrifugall and shear forces acting thereon. The two halves of the root housing after being fitted overthe root ends 45 of rotation of the propeller.

of each of the blades, may be secured in position by a flanged ring 23 and, if desired, a lubricant l sealing washer 24, adapted to cooperate with a ring 25 and a locking member 26 may be em- 5 ployed in order to prevent seepage of oil or grease from the bearing 20.

Means are provided for rotating the blades in the sockets 14 in order to vary the pitch during operation of the propeller, and preferably such means include the hub and are responsive to the thrust of said blades to effect the change in blade angularity in an automatic manner. In the form shown, such means include an operative \\connection between the driving block l0 and the 15 blades, whereby during forward movement of the hub, in response to the thrust force of the blades during operation of the propeller, the pitch of the blades will be automatically changed.

In order to provide such operative connection between the blades and driving block, a suitable cam mechanism is employed which preferably is entirely enclosed within the hub. As shown, such mechanism includes a stud 27 formed integrally with or suitably secured to the flanged ring 23 25 which is adapted to cooperate with cam members 28, a suitable bearing 29 being interposed between these parts in order to permit an efficient and substantially frictionless relative movement.

Referring to Figs. 4 and 5, it will be observed 80 that the cam members 28 cooperating with each of the studsl 27 have been so arranged that the faces thereof are parallel and angularly disposed with respect to an axis substantially parallel with the engine shaft to the end that the effect of 85- torsion on the blades may be substantially nullifed. More particularly, it is pointed out that during operation of a propeller, the torsional or twisting moment, usually referred to as torsion and comprising a combination of the effects of 6@ centrifugal and aerodynamic forces acting on.

of the stud 27 and normal to thecam member 28.

In certain instances, however, it may be desirable to substantially reduce or neutralize the torsion on the blades, in which event suitable counterweights 30 secured to the ring 23 as by means of screws 31, Fig. 7, may be employed, such counterweights due to the centrifugal force during operation of the propeller, exerting an accumulative effect denoted by arrows c and d which serves to substantially offset or overcome the tor- 80 -sion by opposing the force b, such neutralizing force acting from one of the cam members 28 toward stud 27.

In order to yieldingly resist forward movement of the hub, a plurality of expansible resilient I members such as springs 32, are interposed between the hub 15 and a plate 33, the latter being suitably secured to the outer end of the driving f block 10, Fig. 1, as by means of a key 34 and locking nut 35. Preferably, the ends of the resilient members 32 are held in position by studs 36 which latter may also serve as means for posi- -tively limiting the forward movement of the hub thus predetermining the lower pitch limit of the 4 blades. If desired, the mechanism above-described may be encased Within a stream-lined nose member 37 in order to increase the aerodynamical eciency of the propeller and to provide a protective covering therefor.

By the provision of the construction heretofore described, it will be apparent that the expansible members 32 normally are effective to maintain the hub l0 in its extreme rearward position, Fig. 1,

`wherein the pitch of the blades will be a maximum, as indicated by the blade section 8, indicated in dotted lines, Fig. 3. As soon as the propeller is in operation, however, the thrust exerted by the blades is sufficient to overcome the expansive force of the springs 32 and the hub and blade assembly will move forwardly relative to the driving block 10, such movement being effective through the cam '

mechanism

27, 28 and 29 to rotate the blades in the sockets 17 to decrease the As heretofore pointed out, the force of torsion, y

which normally tends to reduce the pitch of the propeller blades during operation, will have no such tendency in the present construction due to the arrangement of the

cam mechanism

27, 28 and 29. However, in order to relieve the parts of any unnecessary stresses or strains the counterweights 30 are effective during operation of the propeller, to substantially reduce or neutralize this force. v

There is thus provided by the present invention a novel propeller construction of the variable pitch type wherein the angularity or pitch of the blades is secured in a simple and automatic manner. By varying the pitch of the blades in response to the thrust thereof, an unusually eflicient propeller installation is secured inasmuch as the pitch assumed under varying conditions will always be such as to yield maximum propeller eiciency. The construction and arrangement of the novel cam mechanism for securing the variation in pitch assures that torsion will have no tendency to alter the pitch of the blades and moreover provides an operable connection which is positive in operation and embodies relatively few parts, thus being especially adaptable for use in aircraft installations wherein such features are highly advantageous.

Though only one embodiment of the invention has been illustrated and described, it is to be understood that the invention is not limited thereto but may be embodied in various mechanical forms. For example the cam mechanism interconnecting the blades and driving shaft may be constructed and arranged in a manner different from that illustrated, it being borne in mind, however, that the same is to be preferably so disposed as to nullify the effect of torsion on the blades. If ,desired the means for positively limiting the forward movement of lche hub may be constructed in such a manner as to be adjustable thus enabling the lower pitch limit to be varied with great ease and simplicity. It is also to be understood that though theguse of the counterweights for neutralizing torsion relieves certain stresses in rthe mechanism, yet such weights may be omitted if desired. Other changes in the construction and arrangement of parts may be made without departing from the spirit of the invention, as will be apparent to those skilled in the art. Reference will therefore be had to the appended claims for a definition of the limits of the invention.

What is claimed is:

1. A propeller comprising a hub, a plurality of radially-extending blades carried thereby, a driving shaft, means for drivably connecting said shaft and hub, means responsive to the thrust of said blades for moving the hub axially of said shaft, andmeans including a Ymechanism for each blade wholly disposed between the root ends of the respective blades and the first named means and operable during such movement to change the pitch of said blades.

2. A propellercomprising a plurality of blades, a rotatable shaft, a hub, means drivably connecting said hub and shaft, said hub being movable with respect to said shaft in response to the thrust of said blades, aligned recesses formed in said first-named means, and means including a mechanism interposed between the root ends of said blades and said first-named means and having portions disposed in said recesses for rotating said blades about their longitudinal axis during such movement of the hub.

3. A device of the class described comprising a rotatable shaft, a plurality of axially alinged propeller blades, a hub for said blades, means comprising a driving block for drivably connecting said hub and shaft, said hub being axially movable of said block in response t0 the thrust of the blades, and means connecting said blades and including a portion projecting into a recess formed in said block to change the pitch thereof during such axial movement of said hub.

4. In a propeller having a driving member, a plurality of blades, means responsive to the thrust of said blades for moving the latter rectilinearly of said member for varying the pitch of the blades, said means including a cam mechanism, and means for neutralizing the torsional tendency of the blades to seek a zero pitch condition.

5. A propeller having a plurality of blades, a shaft for rotating said blades, and means for automatically moving said blades rectilinearly of said shaft for varying the pitch of said blades, said means including a cam, said cam having faces inclined with respect to the axis of said shaft whereby the effect of torsion on the blades is substantially reduced.

6. In a propeller having a plurality of blades, a shaft for rotating said blades, and means for automatically moving said blades rectilinearly of said shaft foiLchanging the pitch of the blades, said means including relatively-movable members, said members being so arranged with respect to the shaft as to nullify the effect of torsion on the blades.

'7. In combination with a rotatable shaft, of a hub, a plurality of blades rotatably mounted in the hub, means for drivably connecting the hub and shaft, the hub being movable axially of said 'means in response to the thrust of the blades, and means comprising a stud connected with each blade for changing the pitch of the latter during axial movement of the hub, and a cam carried by said first-named means cooperating with each stud said studs being axially aligned.A

8. In a propeller having a hub, a shaft for driving said hub, a plurality of blades carried thereby and means responsive to the thrust of the blades for moving said blades rectilinearly of said shaft for varying the pitch, said means including a member so positioned with respect to the shaft as to nullify the effect of torsion on the blade.

9. In a propeller having a plurality of blades, blade-thrust-responsive means for varying the pitch and a pair of counterweights carried by each blade for neutralizing the torsion thereon, said counterweights being diametrically opposed.

10. In a variable pitch propeller having a plurality of blades, means for supporting said blades for lateral movement in response to the thrust thereof, means operable during such thrust-responsive movement to change the pitch of the blades, and a pair of diametrically-opposed counterweights directly secured to each blade and movable bodily therewith during change in pitch to substantially neutralize the effect of torsion on the blades.

11. In a variable pitch propeller having a hub, a plurality of blades rotatably mounted therein, means responsive to the thrust of the blades and including relatively movable members housed Within the hub for varying the pitch of the blades, said members being positioned relative to each other in a manner to substantially nullify the effect of torsion 0n the blades.

12. A variable pitch propeller comprising a hub, a plurality of blades rotatably mounted in the hub, a rotatable shaft, means for drivably connecting said hub and shaft, means disposed entirely within said hub and interconnecting said blades and shaft for rotating the blades in the hub to change the pitch, and a counterweight separate from said pitch changing means directly secured to each blade within the hub 115 for substantially neutralizing the torsion on-the blades.

- 13. A variable pitch propeller comprising a hub, a plurality of blades rotatably mounted in the hub, a rotatable shaft, means for drivably 120 connecting said hub and shaft, said hub being axially movable relative to the shaft during rotation of the latter to vary the pitch of the blades, means disposed wholly within the hub and interconnecting said blades and shaft for ro- 125 tating the blades in the hub during axial movement of the latter relative to the shaft, and a counterweight secured to each blade interiorly of the hub for substantially neutralizing the torsion on the blades.

14. In a propeller having a plurality of blades, a rotatable shaft, a. driving member having a polygonal cross section, a hub for said blades having an aperture receiving said member, said hub being adapted to be driven by the latter 135 and axially movable with respect to said member in response to the thrust of the blades, and mechanisms including cooperating portions carried by said blades and driving member respectively and positioned interiorly of the hub for 140 varying the pitch of the blades in response to the thrust-responsive movement of the hub.

CLINTON H. HAVILL.