US2804155A - Propeller mechanism - Google Patents

Description

Aug. 27, 1957 w. J. BLANCHARD ETAL 2,804,155

PROPELLER MECHANISM Original Filed Sept. 11, 1945 3 Sheets-Sheet l 3 55a 7: Q Z830 a #8 w m m 2% Z /5 20 0 /4 I3 INVENTOR WERNERJBlflM/MRO $1 Mac/V514.

N f! AINES HON/75 .MnRr/N Aug. 27, 1957 w. J. BLANCHARD EI'AL PROPE'LLER MECHANISM s Shets-Sheet 5 Original Filed Sept. 11, 1945 wild.

I r M g st 0L g Ms mmmm m TJ3%B N mmmf lm wme ww I. HO A Mme c T W 5 tates 2,804,155 PROPELLER MECHANISM July 9, 1942. Divided and this application duly 31, 1952, Serial No. 306,464

Claims. (Cl. 170-16033) U in.

This invention relate to controllable pitch propellers for aircraft, and is a division of Serial No. 615,522, now Patent No. 2,612,959, which is a division of Serial No. 450,246, now Patent No. 2,405,285.

One of our objects is the provision of an improved torque unit for a variable pitch propeller of the double acting type including means for applying pressure to and draining fluid from opposite ends of the torque unit.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

Fig. 1 is a longitudinal sectional view of the complete unit mounted on an engine shaft of an aircraft.

Fig. 2 is a transverse sectional view through the regulator housing substantially as indicated by the line and arrows 22 of Fig. l.

Fig. 3 is a sectional view through one of the blade sockets and the regulator plate showing the details of transfer passages substantially as indicated by the line and arrows 33 of Fig. 2.

Fig. 4 is a sectional view of the blade shifting mechanism, with the fluid transfer passages shown in exaggerated relation for the purpose of illustrating more clearly the functional relation of the elements, the view being such as is generally indicated by the branched line and arrows 4-4 of Fig. 3.

Fig. 5 is a skeletonized perspective view with parts shown in section to serve as a flow chart in tracing the fluid circuits.

With particular reference to the drawings, the propeller under consideration is a hydraulically operated constant speed propeller assembled as a self-contained unit that mounts on the standard propeller shaft, and in front of the engine nose. To the extent of being a self contained unit, the structure consists of a hub, a set of shiftable blades, pitch changing mechanism or torque applying units for the blades, and automatic control mechanism therefore built into a single assembly complete and ready for installation and operation upon an available propeller shaft or the like indicated at 10. The engine nose, or gear casing as it is sometimes called, usually ends in a cover plate 12 outward from which the shaft 1% projects for mounting of a desired propeller. The shaft lti provides a shoulder 13 against which is seated a rear cone l4 and in front of which is a splined section 15 having mating relation with a complimentarily splined hub 16 retained in position by a front cone assembly l7 and a shaft nut 18.

in the illustrated embodiment the hub 16 has a rearwardly extending sleeve portion 2% and radiating sockets 22 for reception of blades 24. The sleeve portion 26 has a central aperture providing the splines 26 for mating 2,8e4,l55 Patented Aug. 27, 1 7

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with the shaft splines 15 for transmitting torque from the drive, shaft to the hub assembly. At the rear of the sleeve 20 a comic surface bears upon the rear cone as sembly l4 and with which it is forced into contact by the front cone assembly 17. Thus, the entire hub and blade assembly is securely mounted upon the propeller shaft 1 by axial movement of the hub assembly upon the shaft, thence engagement of the threads in the nut 18 with the threads provided at the end of the shaft 10 and tightening of the nut 18.

The forward end of the sleeve 20 provides a plurality of radially extending bosses 30 each one of which is aligned and centered with respect to a socket 22, each boss supporting an antifriction bearing 32 the outer race of which is carried by or secured to a blade, as will presently be described. Engaging the inner race of the antifriction bearing is a cup-like spline member 34 aligned with the boss 30 by means of dowels 36 where it is held firmly in position by means of a tubular screw 38 and a lock device 40. Secured within the screw 38 there is a tube 42 extending radially outward of the hub to be slidingly received by the central bore 44 of a piston member 46. Secured to the piston member there is a cylindrical skirt 48 whose inner lower surface is splined at 50 to mate with complimentary splines 52 carried by the member 34, and whose outer surface is splined at 54 for mating relation with the splines 56 provided on the inner cylindrical surface of a blade cylinder 58.

The two pairs of splines 50, 52 and 54, 56 are characterized such that for any movement of the piston 46 along the tube 42 and Within the cylinder 58, there will result a predetermined amount of rotation between the member 34 and the member 58. The hub spline 34 is maintained in nonrotative relation with respect to the hub boss 30 by means of the screw device 38 and the dowels 36, wherefore any longitudinal movement of the piston 46 relative to the hub spline 34 and the cylinder 58 will cause rotation of the cylinder 58 with respect to the blade socket 22 within which it is mounted. In the fabrication of the cylinder 58 it may for convenience be divided into two parts such as to include a tubular attaching portion 58a provided with a flange 6t) engaging the outer race of the antifriction bearing 32. An oilseal 62 may also be provided such as to seal with the inside surface of the blade root 64.

The shank of the blade 24 is of a cylindrical contour and has an axial hollowed portion 66 within which is mounted the blade shifting motors or torque applying units just described. In anchoring the blade within a socket a stack of anti-friction bearings 68, here shown to be three in number, are passed over the blade root Where they are retained by a blade nut 70 threaded upon the root portion 64. A lock pin 72 may be threaded or otherwise driven in to prevent rotation of the nut 70 from the end of the blade.

In the hollow 66 of the blade a little beyond the cylinder 58 an assembly is provided for individually balancing each blade against a master. For location of the balancing means, a ring 74 is secured in place within which is press fitted a cup 76 in inverted relation as shown in Fig. 1, and where it may be sweated in place. Centrally within the bottom of the cup 76 there is provided a stud 78 threaded to receive a nut 80. A smaller cup 82 having outwardly flaring walls is secured in place concentric with the bottom wall of the main cup, thus leaving an annular channel 84 for the anchorage of a predetermined quantity of lead or balancing material 88. To perfect the fineness of adjustment in blade balance,

a plurality of shins 943 are provided to thread over thestud 78 where they are held in place by the nut 80.

The torque applying units, consisting of the piston 46 and its cooperating cylinder 53 mountedas stated upon 3 the hub spline boss 30 and supporting a blade moving gear 92 mounted upon the flanges 60 of'the cylinder 58 by means of screws 94, are. now ready for reception of and union with the blade assembly. The blade assembly carrying the stack of bearings 68and the .blade nut 70 along with a hub nut assembly 96 is. thence passed into the open end of the socket 2 2, and the root. portion 64 of the blade is lined up to receive the projecting end of a dowel 98 secured in the flange 60 and blade gear 92. When the blade is pressed into place, which may be done by hand, the stack bearings 68 are passed within the socket and the hub nut assembly 96'threaded intoplace.

As the nut assembly passes inward the outer faces of the stack bearings are urged inward of the socket to take up all lost motion and are preloaded by thus tightening the nut 96 against the bearing32 to oppose centrifugal force of the revolving blade. A seal 100 retained within the nut assembly 96 by snap ring 102 closely surrounds the shank of the blade to prevent loss of lubricant. A lock plate 104 mates with aligned peripheral notches in the socket 22 where it is held in place by a screw 106 threaded with lock wire 108.

Fluid transmission to and from the hub boss 30, and thence to either side of thepiston 46 is accomplished primarily as shown in Figs. 1, 3, 4 and 5, where the tube 42 secured in the nut 38 opens into a chamber 110 provided by the boss 30 and from which exit is made to the exterior of the socket 22 by means of a transfer tube 112. Thus the fluid connection exists from the chamber 114 between the cylinder 58 and pistons 46, by way of the tube 42, chamber 110 to tube 112. A similar tube 115 leads from the exterior of the socket 22 to a drilled passage 116 for reception of a tubular dowel 118 that opens through the bottom of the hub spline member 34 into a chamber 117 between the lower end of the piston 46 and the tubular screw 38. Thus when fluid under pressure is admitted through one of the tubes 112 or 115 to one side of the piston 46, then the fluid on the opposite side thereof is relieved through the other of the transfer tubes, and consequent movement of the piston 46 within the cylinder 58 results in rotation of the blade shank 24 on its bearings within the socket 22, thus effecting a shift in blade pitch.

In this embodiment the shift of the blade pitch is automatic and is hydraulically. controlled so as to result in the speed of the propeller being substantially constant,

or closely maintained with respect to a predetermined setting of amanual control device. A self-contained hydraulic regulator unit 120 is mounted' on the rearward sleeve extension 20 of the hub and has fluid connection with the transfer tubes 112 and 115 by means of tubular dowels 119 as shown in Figs. 3 and 4.

The regulator comprises a plate member 122, a cover member 124 and a sleeve 1260f an adapter assembly that are mounted in sealed relation such as to provide a regulator chamber 128 of annular form and within which are mounted a pump mechanism130, a relief valve 132, a governor valve mechanism 134 and a breather valve assembly 136, each of which is mounted on the plate member 122 or the cover 124 with appropriate connections into the fluid circuit.

With reference to Figs. 1 and 5,'it will be observed that the governor or distributing valve 252 is arranged lengthwise with respect to a radius from the axis or propeller rotation -0. It therefore responds to centrifugal force and acts against the opposing force of the spring 264 through the arm 258 having a relatively fixed point of bearing on the fulcrum roller 260. Adjustment of the spring 264 and movement of the fulcrum roller 260 along the guide arms 280 will operate to determine the point at which the valve member 252 will establish a constant speed, or in other words, will determine the speed of rotation at which the valve within the ported sleeve 234 will equalize or balance fiuid pressures in the distributing lines 142 and 144. If there is an increase of speed over that for which the balance condition obtains a so sustr then the valve member 252 will move radially outward and connect the fluidpressure line with the distributing pipe 144 whereby pressure is admitted to that side of the piston 46 that will effect an increase in blade pitch and result in establishing so much additional load on the blades as to cause a consequent drop in speed of rotation of the propeller, which immediately brings the apparatus back to the specified setting. On the other hand, if the speed of rotation falls below the predetermined setting the spring 264 will operate to overbalance the centrifugal force on; the valve member 252 which allows the, valve. to move radially inward toward the axis of rotation. In so doing the valve 252 operates to connect the pressure line 140 with the distributing line 142 and thence by the associated transfer tubes to the opposite side of the piston 46 which tends to decrease the pitch of the blade and allow the speed of rotation to increase.

The adjustment that is to be effected through the screw device 268 is one that is designed to be made upon the ground, or while the propeller is at rest, and is for the purpose of adjusting the governor mechanism with respect to the general requirements of the engine with which it is associated. Once it is established, it is for the most part allowedto remain in thatfixed condition. In the operation of an air-craft, differing relationor propeller pitch are desirable during the cycles of engine warm-up, take-off, climb, cruising, and dive or other maneuvers. To effect manual control'so as to accomplish immediate setting of the regulator mechanism best suited for the desired" conditions, means are provided for shifting the fulcrum roller. 260 along the guides 280 so as to modify the moments of centrifugal and spring force acting upon the lever 258 and to rearrange their relations or proportions.

Shifting of the fulcrum roller is accomplished by movement of the control ring 288 along or in the directionof the length of the sleeve 20. The ring 288 is slidably mounted on the sleeve 126, and the relative position thereof is accomplished by a plurality of screw shafts 290 having a steep pitched thread passing through the ring, and a plain portion 292 journalled in the rearward thickened portion of the sleeve 126. A stop collar 294 acts as a thrust member on the shaft 290 which also passes through a ring 296 assembled against an adapter ring 298. The adapter ring 298 is channeled to receive a ring gear 300 that meshes with pinions 302 on the'end of the screw shafts 290. 1 An arm 304 joins the ring gear 300 and has provisions for rod or cable connections leading to the pilots compartment. Rotation of the ring gear' 300 causes all of the screw shafts 290 to rotate in unison and as they do so they thread into or out of the ring 288 causing the latter to move axially of the sleeve 126. The shoe 284 riding in the groove 286 of the ring 288 transmits that reciprocable motion to the slider which carries the fulcrum roller 260 toward or away from the point of spring pressure upon the lever 258.

The regulator assembly being completed, that is, with the control elements mounted upon the plate 122 and enclosed by the cover 124 and sleeve 126, it is thence in preparation for mounting on the propeller. hub which is accomplished by slipping the regulator assembly over the rearward extension 20 of the hub and thence threading into place the regulator nut 326. That being done the mechanism contained within the chamber 128 is properly oriented and hydraulically connected through the agency of tubular dowels 119 and the respective transfer tubes with the blade shifting motors or torque applying units. The hub assembly thus constructed is ready for mounting upon the propeller shaft 10 where it seats against the inner cone 14 with the adapter ring 298 secured against to make it more accessible in tightening the installation there is provided a sleeve assembly 330 having lug and notch engagement with the end of the nut 18 and extending forward thereof beyond the terminal rim 332 of the hub 16 and ending in wrench notches 334. Intermediate its ends the sleeve assembly provides a flange 336 appropriately notched to receive tongues 338 on the end of a spinner adapter 340. The sleeve assembly 330 also carries L-shaped leaf springs 342 having an upturned free end adapted to engage the end of the tongues 338 when they are passed through the notches of the flange 336. Closely fitting about the flange 336 of the sleeve assembly there is a flanged sleeve 344 that is secured to the terminal rim 332 by means of a plurality of screw devices 346. The member 344 has a rearward tubular extension 348 telescoping within the bore 350 of the hub 16 so as to end beneath the hub spline bosses 30. This sleeve extension forms a bearing for a coordinating gear 352 meshing with all of the blade shifting gears 92. The coordinating gear has a sleeve portion 354 machined to form the inner race of friction reducing bearing 366 whose outer race 368 is maintained in position by spring ring 370. The member 344 when brought into position by the screws 346 acts as a thrust member for the friction reducing bearing 366. Thus by appropriately mating up the sleeve assembly 330 with the nut 18, and the notched end of the spinner adapter 340 with the notched flange 336, the apertures in the flange of the spinner adapter may be properly aligned with the threaded apertures in the member 344 for reception of the screws 347. Thus a positive lock is provided for maintaining the nut 18 in tightened I relation upon the end of the shaft 10.

While the embodiment of the present invention herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. In a variable pitch propeller, the combination including, a hub having a plurality of sockets within which a plurality of blades are journaled for rotation, said hub having a plurality of blade bosses disposed within said sockets, a torque unit mounted on each boss and operatively connected to a blade for rotating the same, said torque unit comprising a double acting piston having a skirt, a pair of spline members, one of which is secured to the hub boss cooperating with the piston to effect rotative movement of the other spline member upon lineal movement of the piston, said blade having a hollow root for enclosing the torque unit and being drivingly connected to said other spline member, a tubular member anchored in the hub boss and slidably engaged by the piston, and means for introducing and exhausting fluid under pressure to opposite sides of said piston.

2. In a variable pitch propeller, the combination including, a hub having a plurality of sockets, said hub having a plurality of radially extending bosses centrally disposed within said sockets, means journaling propeller blades for rotation within said hub sockets and a plurality of torque units mounted on said bosses and operatively connected to said blades for effecting rotation thereof, each of saidtorque units comprising a double acting piston having a skirt, a pair of spline members, one of which is secured to the hub boss cooperating with the piston to effect rotative movement of the other splined member upon lineal movement of the piston, a tubular nut securing said one spline member to the hub boss, 2. tube secured in the tubular nut and extending in slidable relation through said piston, and fluid passages located in the hub communicating with both sides of the piston, one of said passages communicating with said tube.

3. In a variable pitch propeller, the combination including, a hub having a plurality of sockets, said hub hav.

ing a plurality of radially extending bosses :centrally disposed Within said sockets, means journaling propeller blades for rotation within said hub sockets and a plurality of torque units mounted on said bosses and operatively connected to said blades for effecting rotation thereof, each of said torque units comprising a double-acting piston having a skirt, a pair of spline members, one of which is secured to the hub boss cooperating with the piston to effect rotative movement of the other splined member upon lineal movement of the piston, a tubular nut securing said one spline member to the hub boss, a plurality of dowels interconnecting said one spline and said one hub boss for maintaining alignment therebetween, one of said dowels being hollow, a tubular member secured in the tubular nut and extending in slidable relation through said piston, and fluid passages located in the hub communicating with both sides of the piston, one of said passages communicating with said hollow dowel.

4. In a variable pitch propeller, the combination including, a hub having a plurality of sockets, said hub having a plurality of radially extending bosses centrally disposed within said sockets, means journaling propeller blades for rotation within said hub sockets and a plurality of torque units mounted on said bosses and operatively connected to said blades for effecting rotation thereof, each of said torque units comprising a double acting piston having a skirt, a pair of spline members, one of which is secured to the hub boss cooperating with the piston to effect rotative movement of the other splined member upon lineal movement of the piston, a tubular nut securing said one spline member to the hub boss, a plurality of dowels interconnecting said one spline and said one hub boss for maintaining alignment therebetween, one of said dowels being hollow, a tubular member secured in the tubular nut and extending in slidable relation through said piston, fluid passages located in the hub communicating with both sides of the piston, one of said passages communicating with said hollow dowel, and another of said passages communicating with said tubular member.

5. In a variable pitch propeller, the combination comprising, a hub having a plurality of radially extending sockets, said hub having a plurality of blade bosses centnally disposed within said sockets, means journaling propeller blades for rotation within said hub sockets and torque units mounted on said bosses and operatively connected with said blades for effecting rotation thereof, each of said torque units comprising a double acting piston having an axially extending skirt, a pair of spline members, one of which is secured to the hub boss cooperating with the piston to effect rotative movement of the other spline member upon lineal movement of the piston, said piston being centrally apertured, a tubular nut securing said one splined member to the hub boss, a plurality of dowels interconnecting said hub boss and said one spline member for maintaining alignment therebetween, one of said dowels being hollow, a tube secured in the tubular nut and extending in slidable relation through the center of said piston, and fluid passages within the hub communicating with both sides of the piston, one of said passages communicating with said tube and another of said passages communicating with said hollow dowel.

References Cited in the file of this patent UNITED STATES PATENTS 2,113,438 Allred Apr.-5, 1938 2,147,078 Barish Feb. 14, 1939 2,308,488 Cladwell et al J an. 19, 1943 2,500,692 Martin et al Mar. 14, 1950 2,527,022 May et al Oct. 24, 1950 FOREIGN PATENTS 539.303 Great Britain Sept. 4, 1941

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