US1874332A - Variable pitch propeller - Google Patents

Description

E. B. MOORE VARIABLE PITCH PROPELLER Aug. 30, 1932.

Filed Sept. 13, 1929 4 Sheets-Sheet l INVENTOR Aug. 30, 1932.

E. B. MOORE VARIABLE PITCH PROPELLER Filed Sept. 13, 1929 4 Sheets-Sheet 2 QUHL Q & 8 sl VA k R Q 1 8Q* m .N as aw 3 Q R NN 3 w v i R R R N V H Q INVENTOR A'rfoRNEY Aug. 30, 1932.

E. B. MOORE 1,874,332

VARIABLE PITCH PROPELLER Filed Sept. 13, 1929 4 Sheets-Sheet 3 Aug. 30, 1932. E. B M RE 1,874,332

VARIABLE PITCH PROPELLER Filed Sept. 13, 1929 4 Sheets-Sheet 4 FIGJS.

INVENTOR ATTORNEY Patented Aug. 30, 1932 UNITED STATES PATENT OFFIC E EDMUND 3.1100315, 01 HEM2STELD, NEW YORK, ASSIGNOR 'I'O AEROPLANE & MOTOR COMPANY, INC., A. CORPORATION OF NEW YORK VARIABLE PITCH PROPELLEB Application filed sentemberla, 1929. Serial No. 892,880.

My invention relates to propellers for aeroplanes and more particularly to methods of and means for varying thepitch of such propellers. I g

It is sometimes most advantageous to use a propeller having its blades inclined at one A further object is to provide such means which may be controlled b the operator of the aeroplane from the coc pit thereof.

A further object is to design the most sim ple device of such a nature and to avoid complications so that the device 'will be less like- 7 1y to get out of order. v

A further object is to provide maximum ease of operation in such a device and to avoid danger of breakage of parts of the connecting mechanism.

Further objects are: the elimination, in

such a device, of cams and mechanically or electrically operated clutches; the elimination therein of reversing gears; and the elimination therein of electric batteries, motors, and other heavy electrical equipment.

Further objects will be apparent from a reading of the subjoined specification and claims and from a consideration of the drawings. i

In order to explain the invention more clearly, one embodimentthere'of is shown in the accompanying drawings, in which:

Fig. 2 is a similar view in side elevation of the aeroplane of Fig. 1; i

Fig. 3 is a plan view on a, larger scale of part of the apparatus shown in Figs. 1 and 2, the ropeller blade being shown in horizontal section, the view being taken substantially on the line IIIIII of Fig. 4;

Fig. 4 is a rear elevation of the mechanism shown in Fig. 3 with parts broken away and with parts in section, the view being taken substantially on the line IV IV of Fig. 3 but with the propeller turned through 90 degrees from its position in Fig. 3;

Fig. 5 is a vertical section of (part of the mechanism shown in Figs. 3, 4 an 6 with the propeller in the position of Fig. 4 and the view bein taken substantially on the line VV of ig. 6;

Fig. .6 is a side elevation of the mechanism shown in Figs. 3, 4 and 5 with the propeller in the position of Fig. 3;

Fig. 7 is a vertical section of a clutch used in one form of device embodying my mvention 1 8 is a vertical section of a cushion spring device used in one form of device embodying my invention, the view bein taken ipbstantially on the line VIII I of ig. 9 is a vertical section of the mechanism shown in Fig. 8, the view bein taken substantially on theline IXIX 0 Fig. 8;

Fig. 10 is an elevation of a control level used in one embodiment of my invention;

Fig. 11 is a vertical section of a detail of a control shaft distribution device;

Fig. 12 is a vertical section of mechanism used in one form of my invention for projecting and retracting a pair of friction rings, the view being taken substantially on the line XIL-XII of Fig.13;

Fig. 13 is a horizontal section of the ap aratus shown in Fig. 12, the view beingta en substantially on the line XIII-XIII of Fig. 12;

Fig. 14 is a view similar to Fig. 6 with further parts broken awayand showing a modification of the apparatus disclosed in Fi 6, said modification being also constructe in accordance with my invention; and

Fig. 15 is an enlarged sectional view of part of the apparatus shown in Fig. 14, being somewhat similar to the sectional view shown in Fig. 12.

In general, the first form of apparatus used for illustration of my invention comprises an aeroplane having a tractor propeller, a motor for driving the propeller and means for varying the pitch of the propeller. This means for varying the pitch includes a pair of rolls of which either one may be used separatel as a driving means for two trains of gears. he rolls and gears are mounted to rotate with the propeller and two of the gears mesh with two toothed sectors, one sector being fastened to each of the propeller blades and the two sectors being directly operative to vary the pitch of the propeller. A pair of friction rings are arranged to bear at times separately upon one or the other of the rolls and thus to drive the trains of gears. A control handle is located within the cockpit of the aeroplane and may be operated to retract one and project the other of the rings to cause the pro ected ring to contact with and actuate its cooperating roll, and thus to vary the pitch of the propeller in one direction or the handle may be operated to project the first ring and thus to vary the pitch of the propeller in the opposite direction.

Referringparticularly to Figs. 1 and 2 of the drawings, I have shown an aeroplane generally designated 11 having a cockpit 12 and a propeller 13 driven by a motor 14. The blades 15 and 16 of the propeller 13 are mounted in a hub 17 which is secured to a shaft 18 so that'rotation of the shaft 18 by the motor 14 causes a rotation of the blades around the axis of the shaft 18. The blades 15 and 16 are mounted in the hub in such a manner that they may also be rotated around an axis longitudinal of the blades themselves This last mentioned rotation may be accomplished by trains of gears including worm gears ,19 and 21 (see Fig. 2). Both trains of gears and both worms 19 and 21 may be driven by a single shaft 22 mounted to move with the propeller 13 in hearings on the hub 17 and maintained substantially parallel to the longitudinalaxis of the blades of the propeller. This shaft 22 may be driven by either one'or the other of two friction rolls 23 and 24. As stated above, the friction rolls 23 and 24 are adapted at times to contact with one or the other of a pair of friction rings. The outer ring of the pair is shown in Figs. 1 and 2 and is designated 25. Thru suitable connections including flexible shafts carried in conduits 26, 27 and 28, the friction rings may be moved into and out of contact with the rolls 23 and 24, each of the rings being automatically retracted out of contact, when the other ring is projected into contact. A handle 29 is provided within the cockpit of the aeroplane and is adapted to control the flexible shafts and the movement of the rings and thus through the friction rolls 23 and 24, the trains of gears and the worms 19 and 21 vary the pitch of the blades of the propeller.

. I will now describe in detail the mounting of the propeller blades and the trains of gears by which rotation of the shaft 22 is at times effective to vary the pitch of the propeller blades. As shown in Fig. 5 the hub 17 is formed in two halves 31 and 32. Each of these halves has formed therein adjacent to each end a recess such as those shown at 34 and 35. These recesses are adapted to receivea collar 36 which is mounted for rotation within said recesses. Washers such as 37 and 38 and ball bearings such as 39 may be inserted between the collar 36 and the casing of the hub 17. The inner part of the collar 36 is threaded to receive the inner end of the propeller blade 15 and thus the propeller blade may rotate with the collar about an axis longitudinal of said blade. The halves 31 and 32 may be secured together b split clamp bands 40, 40, 41 and 41* (see ig. 4) and by clamp bolts such as 42, 43 and 44 (Figs. 3 and'4) passing through the flanged ends of the clamps 40, 40 41 and 41*. Pairs of brackets such as 45 and 46 and 47 and 48 (see Fig. 6) maybe mounted on each of the clamp bands 40* and 41 The pair of brackets 47 and 48 may carry journaled in their upper ends a shaft 49 upon which is mounted the worm gear 21 and the brackets 45 and 46 may carry journaled in their upper ends a shaft 51 on which is mounted the worm gear 19.

Referring again to Figs. 4 and 5 it may be seen that the propeller blade 15 has fastened around its periphery adjacent to the hub 17 a bracket 52 clamped securely to said blade by means of the bolt 53. Likewise, the blade 16 has clamped thereto in a similar manner a bracket 54 securely held by the bolt 55. Bushings such as that shown at56 may be inserted between the butt of the pro- 18381161 blade and the associated clamp ring.

et-screws such as that shown at 57 may be inserted in each bracket to maintain the desired relation betweenthe bracket and the propeller blade. The brackets 52 and 54 have inwardly extending arms 59 and 61, respectively, upon which are mounted sector gears 62 and 62 (see Figs. 5 and 3) for meshing with the worm gears 19 and 21, respectively. Thus, rotation of the worm gears 19 and 21 is adapted to cause a rotation of the propeller blades 15 and 16 about their longitudinal axis, the blades turning with their 'collars within the recesses in the hub 17. I I

,As stated above, I provide suitable gearing by-which the worms 19 and 21 may be driven in synchronism from the shaft 22. As shown clearly in Fig. 4, the end of the shaft brackets 68 and 69. The said brackets 68' and 69 may project upward from the propeller hub 17 and continuously rotate with the hub about the axis of the shaft 18. It may be noted that the gears are so arranged that rotation of the shaft 22 in either direc tion about its own axis will cause a rotation of the propeller blades 15 and 16 about their longitudinal axis in directions the one op posite to the other.

As is also shown most clearly in Fig. 4 I provide means responsive to rotation of the friction rolls 23 and 24 for driving the shaft 22. Mounted upon the shaft 22 are two gear wheels 71 and 72 adapted to be driven by the worm gears 73 and 74 and adapted to drive the shaft 22 through the friction clutches 70 and 7 0 (later to be described in detail). The worm gears 73 and 74 are secured respectively to the ends of shafts 75 and 76 which are uppermost when the shafts are in the positions shown in Fig. 4. The shaft 75 may be mounted in bearings in a bracket 77 projecting rearward from the hub 17 and the shaft 76 may be mounted in bearings in a bracket 78 also projecting rearward from the hub 17. Secured to the lower endof the shaft 75 is a gear 81 adapted to be driven by a worm gear 79 secured to one end of the shaft 82. The shaft 82 may be mounted in a bearing 83 projecting rearward from thepropeller hub 17 and may carry at its end opposite to the worm, gear 79 the'friction roll 24. In a like manner the shaft 76 may have secured to its lower end a gear 85 adapted to be driven by a worm gear 84 secured to one end of a shaft 86. The shaft 86 may be mounted in a bearing 87 projecting rearward from the propeller hub 17 and may carry at its end opposite to the worm gear 85 the friction roll 23. It may be seen that rotation of the friction rolls 23 or 245 will cause rotation of the shaft 22 and a consequent variation iii the pitch of the blades of the propeller. Rotation of the friction roll 23 will cause rotation of the shaft 22 in one direction while rotation of the roll-24 will cause rotation of the shaft 22 in the opposite direction. Because of the worm and gear wheel drive from the friction rolls to the shaft 22, the transmission of motion isirreversible- "and rotation of the shaft 22 is ineffective to cause an movement of the 'friction 'iolls 23 inserted the friction clutches and 70" in the connections between the wheels 71 and 72 respectively and the shaft 22. As shown more specifically in Fig. 7 the wheel 72 is not keyed directly to the shaft 22. Surrounding the shaft 22 and splined thereto is a partially conical collar 84 which may slide freely longitudinally of the shaft 22. Another partially conical collar 85 is telescoped over the collar 84 and may rotate around and slide longitudinally thereover. Screw threaded upon the smaller end of the collar 84 are nuts 86 and 87 and a spiral spring 88 is inserted within a recess between the collars 84 and 85 and is ada ted to bear upon the nut 86 and upon a shoul er formed within the collar 85 so that it constantly urges the- collars 84 and 85 to move longitudinally of the shaft 22, as it were, toward each other. This movement tends to wedge the collars within the gear 72 and thus to cause a friction drive between the gear 72 and the shaft 22. However, when the gear 72 is locked against movement by rea-, son of the immobility of the worm 74 the clutch 70" is designed to slip and allow rotation of the shaft 22 without movement of the gear 72. During the slipping of the clutch the collar will be moved away from the collar 84 and will compress the spring 88. The structure and operation of the clutch 70 is similar to the clutch 7 0. If desired, small toggle cams or dogs maybe introduced into the; clutch combination to make the action positive when each gear train picks up the driving motion. I The means for driving the friction vrolls 23 and 24 is illustrated most clearly in Fig. 3, 6, 12 and 13. The rolls 23 and 24 are mounted for rotation concentrically about the axis of the shaft 18, but are not equidistant from said axis. As shown in Fig. 6 the roll 24 registers substantially with the friction ring 25 but the roll 23 is arranged to travel in a path within the friction ring 25. A friction ring rings 25 and 89 to move them into an out 0f contact with the rolls 23 and 24. Within .the guide 91 a rack 93 is secured to the ring 25 and a rack 94 is secured to the ring 89. 7 Similarly in the guide 92 a rack 95 is secured to the ring 25 and a rack 96 is secured to the Means are provided for reciprocatin the ring 89. Extending through the guide casings. 91 and 92, respectively, are- shafts 97 and 98 the former of which carries a pinion 99 meshing with the racks 93 and' 94 and the latter of which carries a pinion 101 meshing with the'racks 95 and 96. It is thus clear that by suitable rotation of the shafts 97 and 98, the friction rings 25 and 89 may be projected to contact with their cooperating rolls or may be retracted to move out of contact with the rolls. Thus, the ring 25.

' may at times serve as a track for the roll 24 and the ring 89 may at other times serve as a track for the 'roll 23. Inasmuch as the pro peller 13 is being continuously rotated by the shaft 18 it is clear that when one or the other of the tracks or 89 has been projected into cont'act'with its associated roll, the movement of the roll around the axis of the shaft 18 will cause a rotation of the associated shafts 82 or 86 and a consequent rotation-of the shaft 22. By reason of the direction of the worm drives, it is also clear that when the roll 23 is in contact with its friction ring 89 the shaft 22 is driven'in adirection opposite to that in which it is driven when the roll-24 is in contact with its friction ring 25.

As shown in Figs. 8 and 9, I, provide meansfor cushioning the drive through the various gears so that a too sudden starting or stopping of the gears will not cause breakage of parts Inasmuch as this device is the same for both of the rolls 23 and 2.4, description of one will suflfice. The friction roll 23 comprises an outer ring 102 having inward projections 103, 104 and 105 and. an inner ring 106 having outward pfojections 107, 108 and 109. A groove 110 is provided between the outer ring 102 and the inner ring106 'and. inserted in this groove between the projections 103, 104, 105, 107, 108 and 109 are compression springs such as the spring 111. Thus movement of the outer ring 102 causes a cushioned movement of the inner ring 106 and consequent rotation of the shaft 22.

One means for distributing the movement ofthe flexibleshaft connection leading from the.cockpit.is shown clearly in Fig. 11. The

, flexible shaft connection from the cockpitis adapted to turn a shaft I V 107 and through it the bevel wheel 108. The bevel wheel 108 meshes with the twq bevel wheels 109 and 111 and thus is adapted 'to drive the shafts 112 and 113. .The shaft 112 is connected to a suitable flexible shaft leading through the conduits 27 and the shaft 113 is connected to a flexible shaft leading through the conduit 28. i

As shown in Fig. 1.0, a spring 114 may be connected to the handle 29 in order to maintain it in either of its operative positions and thus to hold the rings 25 or 89 firmly in contact with therolls 23 and 24.

The operation of my improved variable pitch propeller will be apparent from the above'description. The pilot by movement of the control handle 29 moves the ring 25 or the" ring 89 into contact with one or the other of .he rolls 23 and 24 and by reason of the rotation of the rolls 23 andv 24 around the shaft 18 causes rotation of the shaft 22 in the desired direction. This rotation of the shaft 22 is transmitted through the gearing to the sector gears 62 and 62 and causes rotation of the propeller blades 15 and 16 about their longitudinal axis 'to vary the inclination of the blades with respect to the thrust of the propeller.

I have shown in Figs. 14 and 15 a slightly modified form of apparatus constructed according to my invention, and have used the same numerals to indicate corresponding parts. A shaft 86 carries on one end a worm 84 and on its opposite end a roll 23. A shaft 82 carries on one end a 'worm 7 9 similar to the worm 79 but having the spirals thereof reversed as compared With the spirals of the worm 79. The shaft 82 carries at its opposite end a roll 24. The two rings 25 and 89 are replaced by a single double flanged ring 25 The ring 25 is constructed so as to have two parallel flanges 25 and 25 embracing the rolls 23 and 24. Racks 94 and 96' are attached to the ring 25 in order that the ring may be moved toward and away from the hub of the propeller'to bring the flange 25 or the flange 25 into contact with the rolls 23 and 24. Pinions .99 andlOl are arranged to be actuated in a manner similar to that describedabove in order to move the racks 94 and 96, respectively. I

The operation of this'form of my invention is quite similar to the operation of the previously described form. The pilot, by

operation of the handle 29, is able to rotate the pinions 99 and 101 and thus to move the flange 25 or the flange 25 into contact with the roll 23 or 24. If the flange 25 is moved into contact with the rolls it will cause a rotation of the shaft 22 in one direction while if the flan'ge 25 is moved into contact with the rolls-it will cause opposite rotation of the shafts 82 and 86 and a consequent'opposite rotation of the shaft 22. The rotation of the shaft 22 will, as previously described, cause a variation in the pitch of the blades of the propeller, the direction and amount of the variation being under the control of the pilot by the handle in the cockpit. In the use for instance 24, and its associated parts including'the shaft 82, the worm-79 the bearing'83, the worm wheel 81, the bracket 77,

the shaft 75, the worm 73 and the worm wheel 71 may also'be omitted.

A two bladed tractor propeller is shown in the drawings. I do not desire to limit myself-to such specific types, but if such a course should be deemed advisable, may use a two bladed pusher propeller or a pusher or tractor propeller having mof'e' than two blades. Any unbalance caused by the mechanism on the propeller may be compensated for by suitable counterweights fixed to the propeller hub.

I have illustrated my invention as aproeller for driving an airplane in horizontal 'ght. Propeller blades or air screws made up of win surfaces may also be used for lifting aerial vehicles vertically or substantially vertically as in such devices as helicopters. I may apply my invention'thereto and in the'a pended claims I desire the word drive to be construed as meaning either driving in a horizontal direction or in a vertical direction or in any combination thereof. 1 It is to be understood that the above described embodiments of my invention are for the purpose of illustration only and various changes may be made therein without departing rom the spirit and scope of my invention. a

I claim as my invention: 1. In anaerial vehicle; a propeller; means for rotating the propeller to cause it to drive the aerial vehicle; and means for varying thepitch of the propeller while it is rotating, said last named means comprising a frictlon dr ve wheel, a train of gears driven by sald drive wheel, and a friction clutch ineluded insaid train.

' 2. In an aerial vehicle; a ropeller having a hub and blades; means or rotating the propeller to cause it to drive the aerial ,vehi-.

ole; means forchanging the angle of inclination of all of the blades of the propeller comprising a plurality of similar gear trains mounted onthe hub of said propeller and each connected to one of the propeller blades;

3. In an aerial vehicle; a propeller having a hub and blades ;means' for rotatin the ro-, peller to cause it to drive the aeria vehicle; and means for varying'the angle of inclination of each of the blades of said propeller,

said last named means comprising a pluralit of similar ear trains mounted on the hub 0 said propel er, each train being connected to one of the pro eller blades, a sin le shaft mounted on the ub for driving al of the gear trains, duplicate drive shafts, each of which separately is adapted to drive the single shaft friction drive wheels also mount ed on sald hub, and agear connection 'between the friction drive wheels and the last named drive shafts.

" I. In an aerial vehicle; a propeller having a hub and blades; means for rotating the propeller to cause it to drive the aerial-ve;

hicle; and means for varying the angle f inclination of all of the blades of said propeller, said last named means comprising a plurality of gear trains, each of said gear trains being connectedto one of said profriction drive wheels each connected to one of the last named train of gears.

5. In an aerial vehicle; a propeller having a hub and blades; means for rotating the propeller to cause it to drive the aerial vehicle; and means for varying the angle of inclination of all of the blades of said propeller, said last named means comprising a. plurality ofgear trains each of which gear trains is connected to one of said propeller blades, a single shaft also mounted on the hub for driving both of the said gear trains, a plurality of drive shafts for separately driving the said single shaft, a train of gears connected to each of said drive shafts, a plu rality of friction drive wheels each connected to one of the last named train of gears, the said friction wheels being arranged to travel, in concentric paths, but each friction wheel being positioned at a different distance from the common center of said paths.

6. In an aerial vehicle; a

propeller having a hub and blades; means or rotating the propeller to cause it to drive the aerial vehicle; and means for varying the angle of inclination of all of the blades of said propeller comprising a plurality of gear trains, each of which gear trains is connected to one of said propeller blades, a single shaft also mounted on the hub for driving all of the said gear trains, a plurality of similar drive shafts for separately driving said sin le shaft, trains of-gea'rs connected to said drive shafts, friction drive wheels eachconnected to one of the last named train of gears, and

concentric friction rings upon which the fric- 1 tion wheels may bear. 7. In an aerial vehicle; a propeller having .a hub and blades; means for rotating the propeller to cause it to drive the aerial vehicle; and means for varying the an 1e of inclination of all of the blades of sai propeller comprising a plurality of gear trams mounted on the hub of the propeller, each of said gear trains being connected to one of said propeller blades, a, single shaft also mounted on the hub for driving all of sald gear trains, a plurality of drive shafts for separately driving said single shaft, tgears connected to said duplicate drive sha ts, a pair of friction. drive Wheels each connected to one of the last named train of gears, and non-rotating concentric friction rings upon which the friction wheels may bear.

8. In an'aerial vehicle; a propeller having a hub and blades, means for rotating the propeller to cause it to drive the aerial vea compression hide; and means for varying the inclination of said blades of the propeller comprising racks secured to the blades, a shaft positione adjacent to said racks, worm gears upon said shaft meshing with said racks, a worm wheel also upon said shaft, a second shaft arranged substantially parallel to the longitudinal axis of the propeller blade, a worm gear upon said parallel shaft meshing with said worm wheel, and means including a friction wheel -for driving said parallel shaft.

9. In an aerial vehicle; a propeller having a hub and blades; means for rotatin the propeller .to cause it to drive the aerial vehicle; and means for varying the angle of "inclination of said blades of the propeller comprising a gear train mounted on the hub of the propeller; a friction drive wheel for driving said gear train; and means interposed 1n said gear train for cushioning the drive through the various gears, said last named means comprisin an outer ring formed with internal pro ections, an inner ring formed with external projections and springs inserted between said projections.

10. In an aerial vehicle; a propeller hav- 7 ing a hub and .blade's; means for rotating the propeller to cause it -to drive: the aerial vehicle; and means for varying the angle of inclination of all of the. blades of the pro.- peller comprising a plurality of similar ear trains mounted onthe hub ofthe prope er, each train beingconnected to one blade of the propeller, a single shaft also mounted on the hub of the propeller and connected to said gear trains for drivin said trains, and means for drivin said sing e shaft including a pair of drive-Ls 'aftsiadapted-to se arately and selectiveiy" drive said single sha in op- 1 p'osite directions. v 3 Y 11, Br an airplane,'a'propeller comprising a hub, blades extending radially from-and adapted to turn with respect to said" hub 'about their axes, racks "on said .blades', a plurality of bearing brackets mounted on said hub,=worms revoluble in part of said brackets, and engaging said racks, a sin leshaft revoluble in ,others "of said brac ets and adapted to simultaneously turn said worms, 1

a plurality of operably connected gear reductions terminatin meansifor 's'aid-singfia shaft'and terminatin at the other end in a friction wheel adapte to turn said gear reductions, torque cushioning means interposed in said plurality of gear reductions, a track mountedon said airplane and adapted to engagesaid friction wheel, and control means to optionally'engage said track with said friction wheel.

In testimony whereof I hereunto aflix'my signature. v EDMUND B. MOORE.

at one end in driving

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