USRE20679E

USRE20679E - Variable pitch propeller

Info

Publication number: USRE20679E
Authority: US
Publication date: 1938-03-29

Description

3 Sheets-Sheet 2 C. K. GREENE VARIABLE FITCH PROPELLER March 29, 193s.

original Filed March 14. .1952 :s sheets-sheet s Reissued Mar. 29, 1938 UNITED STATES Re. l20,679

PATENT oFFlcE No. 598,806, March 14, 1932.

Application for reissue March 18, 1935, Serial No. 11,592

11 Claims.

Thisinvention relates to variable pitch propellers of the general character embodied in my U. S. Patent No. 1,782,167, issued November 18,

1930 and having means by which the propeller blades can be adjusted to vary the thrust exerted thereby when the propeller is in operation to the end of enabling maximum eiliciency to be obtained spring.

from the propeller under all operating conditions. Y

It is the purpose of the present invention to provide a variable pitch propeller wherein the blade adjusting mechanism is characterized by its. structural simplicity, compactness and ease of operation to 'smoothly vary the pitch of the blades while the propeller is in operation and in response to actuation of simple and easily operable control means.

Another object is in a variable pitch propeller means for changing the said pitch at the wish of the operator and while the said propeller is operating at full speed and load and which is accomplished quickly, safely and accurately.

Still another object is in mechanism as de#v scribed pitch changing means which is proof against any accidental locking or jamming of parts and with which the operator is restricted to but one possible movement which compels an increasing pitch and a different single movement for decreasing the pitch thus insuring safety and simplicity. Other objects will appear'from the specification which follows.

Only one form of the invention will be described, following which the lnovel features will be pointed out in claims. In the accompanying drawings,

Figure 1 is a vertical central sectional view of one form of variable pitch propeller embodying this invention;

FigureI 2 is a horizontal sectional view taken on the line 2-2 of Figure 1 and looking in the directin of the arrows;

Figures 3, 4, and 5 are transverse sectionalA views taken, respectively on the lines 3-3, 4-4 and 5-5 of Figure 1 and looking in the directions of the respective arrows;

Figure 6 is a fragmentary sectional view 'taken on the line 6 6 of Figure 5 and looking in the direction of the arrows;

Figure '7 is a fragmentary sectional view taken on the line 1-1 of Figure 6 and looking -in the direction of the arrows;

Figure 8 is a view in side elevation of one of two adjusting pins;

Figure 9 is a perspective view of an annular (Cl. 17o-163) B and B' 'of which terminate at their inner ends in stub shaftsl II) and I a mounted in split sleeves I I and Ila journaled in suitable radial and thrust bearings I2--I2a and I3- I3a supported in a hub, I4. Extending diametrically through the hub and fixed thereto is an internally tapered sleeve I receiving the tapered end of the crankshaft I6 .projecting forwardly from the body I1 of a conventional form of Apower plant such as is employed on heavier-than-air craft. The forward end of the crankshaft has threaded engagement with the sleeve I5 at I8 and is locked to the sleeve by means of a nut I9 threaded into'the latter and abutting the forward extremity vof the crank#` shaft.

Fixed in any suitable manner to the inner ends of the stub shafts I0 and Illa are

worm wheels

20 and 20a with which constantly mesh worms 2| and 2Ia, respectively, fixed to shafts 22 and 22a journaled in the hub I4 at diametrically opposed points, as shown in Figure 3. Relatively small gears 23 and 23a are fixed respectively to the shafts 22 and 22a exteriorly of the hub, and constantly mesh with a relatively large gear 2,4 formed integral with a smaller gear 25 and freely mounted on Vthe sleeve I5 for rotation about the axis of the crankshaft I6.

A metal friction disk 26 through which the sleeve I5 and the crankshaft extend, is fixed by screws 21 (Figure 3,) to the hub I4; and a circ'ular casing 28 formed in two semi-circular seov tions clamped together by bolts 29, co-acts with the disk to enclose the

gears

23, 23a, and 24 as shown in Figures 1,2, and 3. The outer side face of the gear 24 is normally urged by a spring 30 into fric-,tional engagement with the disk 26 so that during rotation of the crankshaft the gear 24 and hence the gear 25 will normally rotate with the crankshaft, to the end that the pitchof the blades will remain constant and the blades be locked by the irreversible worm and wheel connections above described.

The spring 30 is in the form of a ring corrugated circumferentially as shown inFigure 9 and interposed between'a ring 3| and a drivinggear 32 the ring being lrotatable and slidable axially on the sleeve I5,so as to abut the gear 25 under the action of the spring, and the gear 32 being fixed to the sleeve so as to positively rotate with the crankshaft. vIn vthe present. instance, the gear 32 is fixed to the'sleeve I5 by slotting the utilizing the internal and external tapers on the sleeve and crankshaft, respectively, to expand thesleeve in the gear as the sleeve isv threaded onto the crankshaft. In the present design, the

vgear 32 is provided with forty-eight teeth; and

a second driving gear 34 is fixed to -the crankshaft rearwardly of the gear 32 to also positively rotate with thecrankshaft is provided with fortyseven teeth of the same pitch as the gear 32.

Constantly meshing with the gear at a oneto-oneratio is a gear 35 fixed to a hollow countershaft 36 rotatively mounted on the axle 31 supported at its ends in a housing 38 and a plate 39 closing the one open end of the housing and rigidly secured to the enginebody l1 by bolts 48, all as shown in Figure 1. The Vclosed end of the housing interengages with the two semi-circular sections of the casing 28 which latter is clamped by the bolts 29 to the housing so as to be supported by lthe housing, as will be understood.

The housing encloses the '

gears

25, 32, and 34 and the countershaft and clutch mechanism to be described presently. y

Splined on the enlarged portion 4I of the countershaft 36 so as to rotate with the latter and yyet be shiftable axially thereof is a clutch member 42 having opposed circular series of clutch teeth 43 and` 44. Upon shifting the clutch member 42 towards the left as viewed in Figure 1, its teeth 43 are adapted to have clutching engagement-with clutch teethI 45 formed on an idler gear 46 rotatably mounted on the countershaft and constantly meshing with the driving gear 32.

When the clutch is shifted towards the right, as viewed in Figure 1, its teeth 44 are adapted to have clutching engagement with clutch teeth 41 formed on a second idler gear 48 also rotatably mounted on the countershaft and constantly meshing with the second driving gear 34. It willI be remembered that the driving gears 32 and 34 are, respectively, provided with forty-eight 'and forty-seven teeth and it is to be noted that the idler gears 46 vand 48 are provided, respectively, with fortyseven and forty-eight teeth, from which it will be understoodthat when the crankshaft I6 is rotating the idler gear 46 will'be driven at a slightly higher speed than thev crankshaft, whereas the idler 'gear 43 will be driven lat a slightly lower speed than the crankshaft.

The clutch member 42 is constructed in two sections rigidly secured together by rivets 49 and co-acting to define an annular groove 58 freely receiving a clutch-collar 5| having relatively short racks 52 and 52a at opposite sides of the counter-.shaft axis and constantly meshing,Y respectively, with gears 53 and 53a fixed to a control shaft 54 journaled in the housing 38 for rocking movement by an operator to shift the clutchmember 42 into clutching engagement with the clutch Ateeth of the idler gear 46 or 43, according as the control shaft is rocked in one direction or l the other from the neutral position shown in Figure 1. y

'Ihe operation of the clutch members is eected by the operator as by the lever 88 which is mounted on shaft 54 and which lever if thrown to rock the shaft 54 inone direction effects the necessary clutch movement and through the mecha- .Y nism described will set up an increasing pitch of the propeller blades while a movement of the lever 3l in the opposite direction will set up a decreasing pitch of 'said blades.

It is to be noted that itis impossible with the clutch means described to engage both clutch members at one time which would result in stripping the gear teeth or otherwise wreck the operative mechanism which would result in disaster. With the mechanism shown a movement in one direction of the lever 88 and shaft 54 engages one clutch element and insures the disconnection of the other clutch element while a reverse movement of the lever 88 engages the other clutch element while insuring the disconnection of the first named clutch element. 'Ihere is therefore no possibility of locking or jamming or damaging the parts and no possibility of rendering the mechanism inoperative as would be the case where `independent clutch elements may be independently and selectively actuated by the operator.

Safety is thus insured.

Constantly meshing, respectively, lwith the gears 53 and 53aare pinions 55 and 55a rotatably mounted, respectively, on alined stub axles 56 and 56a fixed in the housing 38 at dia'metrcally opposed points'relative to the axis of the crankshaft I6. Fixed, respectively, to the pinions and 55a are cams 51 and 51a. in the formof disks plates 68 and 68a, are pins 63 and 63a, rotatably. mounted in bores 64 and 64a in the housing 36 and having flanges 65 and 65a intermediate their ends abutting a shift collar 66 through which the pins extend.l The shift collar 66 is freely mounted on the ring 3l and 'abuts an annular an'ge 61 formed on the latter for co-action therewith in shifting the ring to the right as viewed in Figure 1, upon rocking the'clutch control shaft 54 in either direction from the neutralv position shown in Figure 1, all for the purpose 'of relieving the load of the spring 38 from Vthe gear unit 24-25, and hence, relieving the pressure of the gear 24 from the friction disk 26, so'that the gear unit 24-25 will be free to rotate relative to the crankshaft I6. v

.That this operation will be effected will be clear froma consideration of Figures 2, 5 and,

to draw the latter with the pins 6 3 and 63a, shift collar 66 and ring 3| as a unit to the rightfas viewed in Figures 2 and 6, against the tension of'the spring 38. lIt is to be noted that this operation is effected upon the initial rocking movement of the control shaft from neutral posi- -tion and prior to clutching engagement of thel teeth of the clutch member 42 with either the 66 from the confronting face of the ange 61 on the ring 3|, to the end of enabling the spring 38 to properly function in' maintaining the gear 24 in frictional engagement with the friction disk as upon rocking of the control shaft in either direction the flattened portions 58 of the cams 51 and 51a will co-act with the flattened portions 6I of the openings 59 in the plates 68 and lillav Cil 28 during normal operation of the propeller. 'I'he for co-action with radial notches 18 in the shift collar 66, in preventing rotation of the pins, it being understood that theaction of the spring 3D is to maintain the shift collar in engagement with the flanges. As shown in Figure 4, a lug 1| formed on the housing 38 is engaged by the shift collar 66 and acts to prevent any possible rotation of the latter when shifted by the cams 51 and 51a, it being assumed that the crank shaft is to rotate in the direction of the arrow in this figure.

The operation of the propeller is as follows:- With the control shaft 54 and clutch member 42 occupying the neutral position shown in Figure 1, and the crankshaft I6 rotating to drive the propeller therewith, the gear unit 24-25 will rotate with the crankshaft due to the friction set up between the gear 2.4 and the friction disk 26, The countershaft 36 along with the clutch member 42 will thus be driven idly by the

mating gears

25 and 35; and the idler gears 4G and 48 will also be rotated idly upon the countershaft by the driving gears 32 and 34, respectively. As there is no relative movement between the gear unit 24-25 and the crankshaft I6 under these conditions, the pitch ofthe blades B and B' will remain unchanged, andthe blades will be locked due to the fact that .

theworm wheels

28 and 20a cannot drive4 the respective worms 2| and` 2|a.

When it is desired to change the pitch of the blades in one directiony the control shaft 54 is rocked for example from the neutral position shown in a direction to shift the clutch member 42 into engagement with the clutch teeth of the idler gear. 46, it being remembered that upon initial movement of the clutch member, the force of the spring 30 will be relieved from the gear unit 24-25`so that the latter will be free for rotation relative to the crankshaft. As the idler gear 46 is" now locked to the countershaft,V and is being driven by the gear 32 at a speed slightly inA excess of' crankshaft speed, it will be clear that the' gear 35 will co-act with the gear 25 to drive the gear unit 24-25 at a speed slightly in excess and in the same direction as the crankshaft, with the result that the gears 23 and 23a. will not only revolve aboutthe axis of the crankshaft but will also be rotated about their own axes by the gear 24, thus causing the worms 2| and 2|a to drive the

worm wheels

20 and 20a, respectively, and vary the pitch of the blades in one direction. i

To change the pitch of the verse direction, the control. shaft 54 is reversely rocked from neutral position to shift the clutch member 42 into engagement with the clutch teeth of the idler 48. As the idler gear 48 is now locked to the countershaft and is being driven by the gear 34 at a speed slightlykless than crankshaft speed, the gear 35 will co-act with gear 25 to drive the gear unit 24-25 at a speed slightly less than, and in the same direction as, the crankshaft, thus driving the gears 23, 23a, worms 2| idler gear 48 t'o the countershaft 36, these gears v will be positively driven by the respective drivblades-in the reing gear 32 or 34 to cause the gear unit 24-25 to be driven in one and the same direction as the crankshaft, but either in excess or less than crankshaft speed, depending on whether the idler gear .46 or 48 is in use,'to the en d of increasing or decreasing the pitch of the blades. It will be understood that-when the desired adjustment of the blades has been effected, the control shaft 54 is moved to the neutral position, leaving the blades locked in the position to which they have been adjusted. Any suitable operative connection (not shown) can be provided for actuating the control shaft from a remote point convenient to the pilot of the aircraft.

" What is claimed is:

1. A rotary propeller having blades mounted for adjustment to vary the pitch thereof; means including a gear mounted for rotation about the propeller axis for moving the blades to vary the pitch thereof in one directionor the other according as the gear is driven at a speed in excess of or less than propeller speed; a pair of idler gears separately mounted for independent rotation about a common axis; means for driving said idler gears respectively at speeds in excess and less than propeller speed; and means for operatively connecting one idler gear or the other to the first mentioned gear, to accordingly drive the latter at a speed in excess or less than propeller speed.

2. A rotary propeller having blades mounted for adjustment to vary the pitch thereof; means including a gear mounted for rotation about the propeller axis for moving the blades to vary the pitch thereof in one direction or the other according as the gear is driven at a speed in excess or less than propeller speed; a pair of idler gears separately mounted for independent rotation about a common axis; a pair of driving gears xed tovrotate with the propeller and meshing 4' with the idler gears4 to drive one of the latter l 3. A rotary propeller having blades mounted.

for vadjustment to vary the pitch thereof; means including a gear mounted for rotation about the propeller axis, for moving the blades to varythe pitch thereof in one direction or the other according as the gear is driven at a speed in excess of or less than propeller speed; a pair of idler gears separately mounted for independent rotation about a common axis; means for .driving said idler gears respectively at speeds in excess of and less than propeller speed; and means including a clutch for operatively connecting one idler gear or the other to the first mentioned gear, to accordingly drive the latter at a speed in excess of or less than propeller speed.

4. A rotary propeller having blades mounted for adjustment to vary the pitch thereof; means including a gear mounted for rotation about the propeller axis, for moving the blades to vary the pitch thereof in one direction or the other according as the gear is driven at a speed in excess or less than propeller speed; a pair of idler gears mounted for rotation about a common axis; means for driving onek idler gear at a speed in at a speed less than propeller speed; means in- .excess of propeller speed and the other idler gear cluding a clutchl member for operatively .con-

necting one idler gear or the other to the Aiirst for adjustment to vary-the pitch thereof; means including a gear mounted for rotation about the propeller' axis for moving the blades to vary the pitch thereof in one direction or the other according as the gear is driven at a speed in excess or less than propeller speed; a countershaft; a gear fixed to the countershaft and operatively l to the first mentioned gear to drive the latter;

two idler gears rotatably mounted on the countershaft; two driving gears fixed. for rotation with the propeller about the axis of the latter; the driving gears meshing, respectively, with the idler .gears to drive one of the. latter at a speed in excess of propeller speed and the other idler gear at a speed less than propeller speed; a clutch member splined on the countershaft; and means for shifting the clutch member into clutching engagement with one idler gear or the other to either drive the= first mentioned gear at a speed in excess or less than propeller speed.

6. A -rotary propeller having blades mounted for adjustment to vary the pitch thereof; means including a gear mounted for rotation about the propeller axis, for moving the-blades to vary the pitchA thereof inl one direction or the other according as the gear is driven at a speed in excess or less than propeller speed;'a countershaft; a gear fixed `to the countershaft and koperatively to the iirstmmentioned gear .to drive the latter; two idler gears rotatably mounted on the countershaft; two driving `gears fixed for rotation with the propeller about the axis of .the latter; the driving gears meshing, respectively, with the idler gears to drive one of the latter at a speed in excess of propellerspeed and the other idler gear at a speed less than propellerl speed; a clutch member splined on the counter shaft;` a clutch -collar .rotatablyreceiving the clutch member and having racks thereon; an oscillatory control shaft; and gears xed to the control shaft and meshing with the racks for coaction therewith in shifting theI clutch member into clutch engagement with one idler gear or the other toeither drive the first mentioned gear at a'speed in excess or less than propeller speed.

7. A rotary propeller having blades mounted for adjustment to vary the pitch thereof; means includirm a geax'fmounted for rotation about the propeller axis, for moving the blades to Yvary the pitch thereof in one direction or the other according as the gear is driven at arspeed in excess or less than'propeller speed; a friction memberrotatable with the propeller; means for urging said gear into engagement with the friction member to cause the gear to be driven by friction with the propeller; two means, one for driving said gear-'atra-speeddn excess of propeller speed and the other for driving said gear at a. speed less than propeller speed; means for selectively rendering one or the other ofk said two means active to drive said gear; and means for renderingthe' urging `means^ ineffective when f either of' said twomeans is active so vthat said gear. willbe free to be driven at a speed relative to propeller speed@ a 20,679 mentioned gear, to accordingly drive the latter 8. A rotary propeller having blades mounted for' adjustment to vary the pitch thereof; means including a gear mounted for rotation about the propeller axis, for moving the blades to vary the pitch thereof in one direction or the other according as the gear is driven at a-speed in excess of or less than propeller speed; a friction `member rotatable` with the propeller; spring,

means for urging said gear into engagement with the friction member to cause the gear to be frictionally driven with the propeller at propeller speed; means for selectively driving said gear at a speed in excess of or less than propeller speed; and means for relieving said gear of the urging action of said spring means when the last means is active, so that said gear will be free to be driven ata speed relative to propeller speed.

9. A rotary propeller` having blades mounted for adjustment to v ary the pitch thereof; means including a rotatable memberl for moving the blades to vary their pitch in one direction or the other accor'ding as the rotatable member is driven at a speed in excess of or less than propeller speed; two idler members mounted for rotation about a common axis; means responsive to the rotation of the propeller to drive one of said idler members at a speed in excess of propeller speed and the other idler member at a speed less than propeller speed; and means for operatively connecting one idler member or the other to the rotatable member, to accordingly drive the latter at a speed in excess of or less than propeller speed.

10. A rotary propeller having blades mounted for adjustment to vary the pitch thereof; means including a gear mounted for rotation about the propeller axis, for moving the blades to varvv the pitch thereof in one direction or the other acter; the driving gears meshing, respectively, with the idler gears to drive one of the latter at a speed in excess of propeller speed and the other V idler gear atta speed less than propeller speed; a'clutch member splined on the countershaft; a clutch collar rotatably receiving the clutch member and having racks thereon; an oscillatory control shaft; gears fixed to the control shaft and meshing with the racks for co-action therewithin shifting the clutch member into clutching engagement with one idler gear or the other to either drive the first mentioned gear at a speed in excess of or less than'V propeller speed; a friction member rotatable with the propeller; spring means for urging the first mentioned gear into engagement with the friction member; and means for removing the load of the spring means 'from the first mentioned gear prior to engagement of the clutch member with one idler gear or the other.

l1. A rotary propeller having blades mounted for adjustment to'vary the pitch thereof; means including a gear mounted. for rotation about the propeller axis. for moving the blades to vary the pitch thereof in ope direction or the other according as the gear is driven at a'speed in excess of or-less than propeller speed; a countershaft; a gear fixed to the countershaft and operatively to the rst mentioned gear t'o drivel the countershaft; two driving gears fixed for rotation with the propeller about the axis of the latter; the driving gears meshing, respectively, with the idler gears to drive one of the latter at a speed in excess of propeller speed and the other idler gear' at a speedless than propeller speed; a clutch member splined on the countershaft; a clutch collar rotatably receiving the clutch member and having racks thereon; an oscillatory control shaft, gears xed to the control shaft and meshing with the racks i'or co-action therewith in shifting the clutch member into clutching engagement with one idler gear or the other to either drive the rst mentioned gear at a speed the clutch memberwith one idler gear or the other.

CLARENCE KIRK GREENE.