US1967435A - Propeller - Google Patents

Description

J. SQUIRES PRQPELLER July 24, 1934.

Original Filed March 28, p.950 2 Sheets -Sheet 1 lNVENTOR Jo/m? Eqwzwrea.

BY- a ATTORNEY Ji y 2 3934* J. $QUIRES 1,967,435

PROPELLER Original Filed March 28. 1930 '2 Sheets-Sheet 2 l l I INVENTOR J'o/rn fi vzjres.

' this nature which Patented July 24, 1934 UNITED STA PROPELLER John Squires, Hagerstown, Md. Continuation of application Serial No.,439,615,

vMarch 28, 1930. This 1931, Serial No. 567,341

application October 7,

21 Claims. (01. 170-173) This invention relates to propeller hubs of the type shown in my application Serial No; 439,615 filed March 28, 1930, of which this is a continuation.

The main objects of this invention are to provide an improved construction of propeller blade supporting hub; to provide a hub construction which permits the blades to be adjusted to vary the pitch thereof; to provide a two-piece hub 19 construction in which the nut for securing the hub to a drive shaft aids in holding the hub members in assembled relation; to provide a simple construction of hub which will securely grip the base flange of a propeller blade to hold it rigidly in adjusted position; to provide a construction in which such gripping of the flange of the blades will serve to align the hub halves; and to provide improved and simple means for balancing the hub to compensate for variations in weight; and to provide distinct elements for withstanding the tensional and torsional forces imposed upon a propeller hub.

Other objects of the invention are to provide hub bosses on the parts of a two-piece hub struc- 5 ture which abut each other before the edges of the shell, or walls of the blade receiving socket contact so as to allow for sufllcient clearance to enable the blade to be firmly clamped by the sides of the socket; to provide a clearance of permits clamping and unclamping of the propeller blades without disturbing the mounting of the hub on the propeller shaft; to provide hub bosses of this character which-are integral with, or otherwise connected only at their outer ends to limited diametrically opposite portions of the parts of the shell, re-

spectively, so as to leave the sides of the shell free for a substantial amount of circumferential movement whereby to enable it to apply pressure 0 on the blade flanges substantially throughout their entire circumference and to relieve the hub bosses of the tension developed in the hub by centrifugal action upon the blade during rotation of the propeller; to provide a hollow substantially cylindrical shell in a hub structure of this kind through which the interior of the end portions of the blades communicate with each other and which receives substantially all the tensional force resulting from the tendency of the blades to move outwardly during rotation of the propeller; to provide shell and hub boss portions in a propeller hub which substantially independently receive the tensional and torsional forces applied on the hub respectively; and to provide shell and hub boss structures which are particularly adapted to withstand forces of the above respective types.

' An illustrative embodiment of this invention is shown in the accompanying drawing, in which:

Figure 1 is a front elevation of a propeller which 00 has a hub that embodies the invention.

' Fig. 2 is a fragmentary view, partly in horizontal section and partly in side elevation, of the central portion of the propeller illustrated in Fig.

1, showing the hub structure somewhat in detail. as

' Fig. 3 is a view, partly in elevation and partly in vertical section, taken on the line 3-3 of Fig. 1.

Fig. 4 is an end elevation showing the hub partly in section with the propeller blades removed.

Fig. 5 is an end elevation of the hub.

Fig. 6 is an enlarged fragmentary horizontal section, taken on the line 6-6 of Fig. 3.

In the construction shown in the drawing, the hub has a body portion generally designated at l, which includes a pair of complementary sections :5 2 and 3, each having an outer shell portion 4. and a tubular boss 5 in which a tapered'bore' 6 is formed for receiving a propeller shaft '1. The respectively opposite ends of the shell portions 4 are open for admitting the root end portions 8 of so a pair of propeller blades. Formed in the inner periphery of the shell sections 4 are sockets or undercut grooves 10 having outer walls 11 substantially parallel to the planes of the open ends of the shell, and an inner wall 12 inclined with 5 respect to such planes, for receiving and wedgingly clamping the single outwardly extending annular flanges 13 of the propeller blades. This last feature is broadly disclosed and claimed in my earlier application for Letters Patent of the United States for Improvements in propeller, filed August 28, 1929, Serial No. 388,901.

The inner abutting extremities of the 'hub bosses 5 extend slightly beyond the registering edge portions of the shell sections 4 so as to nor-' g5 mally contact with each other before the edges of the shell section meet, during assembling of the complementary parts of the hub from opposite directions. This construction provides a clearance 14 between the adjacent edges of the shell halves. The hub bosses 5 are integrally joined, or otherwise connected only at their outer extremities with limited portions of the shell sections 4. I

The sections 2 and 3 of the hub are held in true 05 alignment by the tapered flanges 13 of the propeller blades fitting into their complementary grooves 10 in the shell portions 4. Where the drive shaft which is received in the hub bosses 5 is not of the spline type, such shaft, byproperly fitting the hub bosses 5 may also serve to hold them in proper alignment, but this may ordinarily be eliminated from consideration as an aligning means.

Means are provided for securing the two complementary sections 2 and 3 of the hub together and comprise a plurality of bolts 15 which pass through and loosely fit the openings provided therefor in the integrally formed outwardly extending shoulder or lug portions 16 on the sections 2 and 3 of the hub. The bolts 15 are provided with castellated nuts 17 which are secured against movement thereon by cotter keys 18. A.

plurality of weights in the form of washers 19 may be interposed under the nut 17 for balancing purposes. The heads of the bolts 15 and those washers l9 contacting against the shell sections 4 are'preferably formed with a spherical seat fitting complementary sockets 19 in the extremities of the lugs 16 so as to permit ready alignment of the bolts without setting up bending stresses in them.

The number of weights or washers may be increased or decreased in order to secure a balanced device. Although the correct balance may be acquired by employing washers of diflerent thicknesses all formed from the same material, or a plurality of relatively thin washers of the same material, I prefer to form all the washers of the same dimensions and vary the material from which they are made so as to obtain the correct weight distribution. In other words, I prefer to make some washers of aluminum, some of steel, some oi. brass, etc.

It will be apparent that inasmuch as the washers 19 may be positioned at either end of each of the bolts 15 and because the ends of the bolts are disposed approximately in quarter circles with respect to the axis of the hub, by proper distribution of the washers 19 any condition of unbalance in the propeller may be corrected by proper application of the washers.

Obviously all of the washers 19, except those provided with a spherical face and seating directly against the sockets 19 and which are provided in any case, function only as balancing weights and are not otherwise necessary to the structural unity of the hub structure, and consequently may be considered as "non-structurally functioning washers.

The hub is secured on the drive shaft by nuts 20 secured on the threaded tip end 21 of the drive shaft 7 in the usual manner. A cover nut 22-is threaded into theouter interiorly threaded rim 23 of the shell portion and may be also utilized for withdrawing the hub from. its'tapered shaft in the event of removal.

In assembling the propeller, the preferable mode of operation is to mount the hub halves on the engine or other shaft with the-blades in place and the bolts loose. lhe hub halves are then drawn firmly together by means of the nut 20 or equivalent means with the bolts 15 loose.

The abutment of the inner extremity oi the hub bosses 5 in advance of the adjacentedges or the shell sections 4 provides a substantial gap or clearance between these edges. it will be understood that this gap or clearance between the adjacent edges oi the shell sections 4 corresponds with a radial clearance between the faces oi the blade flanges l3 and the complemen ary surfaces of the grooves to so that although the two halves of the hub are secured together on the shaft against relative movement with the bosses 5 in contact, the blades, as long as the bolts are in loosened condition, are free to turn about their respective axes for the purpose of pitch adjustment. Because of the inherent resiliency of the shell sections 4, which may be constructed of steel, duralumin or any other suitable metal, as soon as the blades have been located at a definite pitch, tightening of the bolts 15 will radially contract the hub shell sections 4 about the blade flanges 13, eifecting a clamping contact around substantially the entire circumference of the flanges l3, and firmly fix the blades in their pitch adjusted position. In a like manner, when the blades are thus clamped in a fixed pitch position, such position may be readily adjusted to a difierent value by simply loosening the bolts 15, which thus releases the blades for rotation and permits the change in pitch to be efiected, changing the pitch and again tightening the bolts to hold the blades in their new position.

The hub bosses 5 are particularly designed with a view to withstand the torsional forces applied thereon during driving of the propeller by the propeller shaft 7 and the connection of only the outer extremities of the hub bosses to limited portions of the shell sections prevents the hub bosses from receiving the tensional forces to which the shells are subjected. The shell sections 4, in turn, are particularly designed to directly withstand the relatively great tensional forces to which they are subjected by the tendency of the propeller blade to move outwardly under centrifugal action during rotation of the propeller, and this independently of the hub bosses by reason of the limited junctions between the shell sections and the hub bosses. As a result, the shell sections and hub bosses are subjected substantially only to the forces which they are particularly adapted to withstand.

Although but one specific embodiment of this invention has been herein shown and described, it will be understood that numerous details of the construction shown may be altered or omitted without departing from the spirit of this invention as defined by the following claims.

What I claim is:

1. A propeller blade supporting hub comprising a body member having a bore therethrough for receiving a drive shaft, a plurality of blade sockets radially disposed with respect to the axis of said drive shaft bore, said body member being split perpendicularly to the axis of said drive shaft bore and diametrically of said blade sockets, a plurality of bolts extending through said split portions for clamping propeller blades in said sockets, and non-structurally functioning balancing weights carried by said bolts.

2. A propeller blade supporting hub comprising a body member having a bore therethrough for receiving a drive shaft, a plurality oi blade sockets radially disposed with respect to the axis of said drive shaft bore, said body member being split perpendicularly to the axis of said drive shaft bore and diametrically of said blade sockets, a plurality of bolts extending through said split portions for clamping propeller blades in said sockets, and a plurality oi balancing weight washers carried by saidbolts.

3. In a propeller structure, in combination, a hub and blades, said hub being separable and adapted to clamp said blades therebctween, nonstructurally functioning replaceable weights for balancing said propeller, and a coon means for securing the parts said hub together and said weights thereto.

in combination with a propeller, a hub 15'.

formed of a plurality of separable parts, bolts for securing said parts together, and weights for establishing a balanced relation of said propeller secured to said hub by said bolts, said weights being in the form of washers encircling said bolts.

5. In combination with a propeller, a hub provided with socket members for removably receiving propeller blades, bolts for clamping said socket members about said blades, and non-structurally functioning weights for balancing said propeller secured thereto by said bolts.

6. A propeller including a hub comprising a pair of complementary members each having an opening therethrough and aligned with each other for the reception of a drive shaft, each of said members including a semi-cylindrical shell, side edge portions of said shells being yieldable for clamping effect and said shells cooperating to form blade receiving sockets, the inner surfaces of said sockets being provided with'an annular groove of tapered cross section, blades for reception in said sockets, each of said blades having an annular flange of tapered section adjacent its root, said flanges being received in the corresponding of said grooves with opposite surfaces thereof contacting with the complementary surfaces of said grooves whereby to lock said blades against axial movement with respect-to said hub, and means for radially contracting said shells about said flanges to hold said blades against rotation in their sockets.

7. A propeller including a hub comprising a pair of complementary members each having an opening therethrough and aligned with each other for the reception of a drive shaft, each of said members including a semi-cylindrical shell, side edge portions of said shells being yieldable for clamping eifect and said shells co-operating to form blade receiving sockets, the inner surfaces of said sockets being provided with an annular groove of tapered cross section, blades for reception in said sockets, each of said blades having an annular flange of tapered section adjacent its root, said flanges being received in the corresponding of said grooves with opposite surfaces thereof contacting with the complementary surfaces of said grooves, the engagement between said flanges and said surfaces of said grooves forming the sole means of support and retention for said blades in said sockets. I

8. A propeller including a hub comprising a pair of half-hub sections each including a semicylindrical shell, a shaft boss integrally secured to each of said shells midway between the ends thereof and each with its axis perpendicular to the axis of the corresponding shell, the free side edge portions of each of said shells being movable in a direction generally radial with respect to the axis thereof in a plane perpendicular to said axis and intersecting the corresponding boss, said shells cooperating to form sockets, a blade recelved in each of said sockets, and means for moving said free side edge portions to clamp said blades in said sockets, said bosses generally spacing said free side edges whereby to substantially limit the clamping effect of said shells on said blades to contraction of said sockets through said movement of said free side edges of said shells.

9. A propeller hub comprising a pair of halfhub sections each including a semi-cylindrical shell, a shaft boss integrally secured to each of said shells midway betweenthe ends thereof and each with its axis perpendicular to the axis of the corresponding shell, the free side edge portions of F each of said shells being movable both in a direction generally circumferentially of said shell and in a direction generally radial with respect to the axis thereof in a plane perpendicular to said axis and intersecting the corresponding boss, said bosses projecting axially thereof beyond said free side edge portions and adapted to contact with each other whereby to maintain said portions in generally spaced relation.

19.; A propeller hub comprising a pair of integral half-hub sections, each including a shaft boss and a semi-cylindrical shell disposed with their axes in substantially perpendicular relation, said halfsections adapted for assembly with said shells in opposed relation whereby to form blade sockets, said bosses adapted to contact in assembly to at least initially space the opposed edges of said shells, and the free edges of said shells being movable radially of said shells in a plane perpendicular to the axes of said shells and passing through said bosses for clamping effect.

11. In an airplane propeller in combination, a hub comprising a pair of complementary members having aligned openings therethrough for a drive shaft, said hub having a plurality of blade sockets disposed with their axes perpendi'cular to the axes of said drive shaft opening, a portion of each socket being formed in one of said members and another portion in the other of said members, each of said sockets having a groove formed internally thereof, a propeller blade having a radially extending flange at the root thereof, said flange being received by said hub comprising a pair of half hub sections, each of said sections comprising a semi-cylindrical shell and a centrally located boss secured thereto at one end only, said semi-cylindrical shells cooperating with each other to form opposed-blade sockets, each of said sockets having an internal annular groove disposed in a plane perpendicular to the axis thereof, a pair of propeller blades each having a circumferentially extending flange at its root end, said blades being received in said sockets with said flanges received in said grooves and maintained out of contact with the remainder of said hub thereby, and means for clamping said hub halves together and said blades in said sockets.

13. Inan airplane propeller, in combination, a hub comprising a pair of half -hub sections, each of said sections comprising a semi-cylindrical shell and a centrally located boss secured thereto at one end only, said semi-cylindrical shells' cooperating with each other to form oppositely extending blade sockets, each of said sockets having an internal annular groove disposed in a plane'perpendicular to the axis thereof, each of said grooves having an outer wall disposed in a plane normal to the axis of the corresponding socket and an inner wall. disposed at an angle to such axis, a pair'of propeller blades each having a circumferentiallyextending flange at its root end, said blades being received in said sockets with said flanges received in said grooves and maintained out of contact with the remainder of said hub thereby, and means for clamping said hub halves together and said blades in said sockets.

, 14. man airplane propeller in combination, a hub comprising a pair of half hub sections, each of said sections comprising a semi-cylindrical shell and a boss secured thereto with its axis perpendicular "to the axis of said shell and disposed centrally of said shell and in contact therewith at one end only, said shells cooperating with each other to form a pair of opposed blade sockets, said bosses being bored in alignment axially thereof, a propeller shaft received in the bores of said bosses, means on said propeller shaft for maintaining said hub halves against separation, each of said sockets being internally'provided with an annular groove, a pair of propeller blades each having a circumferentially extending flange at its root received in the correspoding grooves of said sockets, said flanges co-operating the said grooves to maintain the remainder of said propeller blades out of contact with said hub, and means for contracting said sockets about said flanges.

15. In an airplane propeller, in combination, a hub including a pair of halves separated from each other centrally of said hub, each of said halves comprising a shell of approximately semicircular section and a central hollow boss secured centrally thereof at one end only, said hollow bosses cooperating to receive a drive shaft and thereby transmit the torque therefrom to, said shells independently of other stresses set up in said hub, said hub halves co-operating to provide a pair of oppositely disposed blade sockets, each of said sockets being internally provided with an annular groove, a blade for each of said sockets, each of said blades having a circumferentially extending flange thereon adjacent the root thereof, said flanges being received in the corresponding grooves of said sockets whereby to secure said blades to said hub and maintain the remainder of said blades out of contact with said hub means for contracting said sockets about said flanges.

16. In a hub for aeronautical propellers, op-

posed complementary parts having abutting tueral grooves at their opposite ends for receiving end flanges of propeller blades, the edges of said shell portion adjacent said grooves being normally spaced with respect to each other in the planes of said groove when said hub bosses are in abutting relationship, and means for drawing the edges of said shell portions together so as to firmly clamp the end flanges of said blades between the outermost parts of said shell portions.

18. In a hub for aeronautical propellers, opposed complementary parts having abutting tubular hub bosses for receiving a propeller shaft, and including outer shell sections forming sockets for receiving a pair of propeller blades and integrally joined at limited portions only with the-outer extremities of said hub boss so'as to relieve the latter of substantially all the tension developed in saidhub by centrifugal action upon the blades during rotation of said propeller.

19. In a hub for aeronautical propellers, op-

posed complementary parts having abutting tubular hub bosses for receiving a propeller shaft, and including outer shell sections forming sockets for receiving a pair of propeller blades normally having a clearance between their registering edges when said hub bosses are in abutting relationship for enabling firm clamping of said blades, each shell section being integrally joined at a limited portion only with an outer extremity of one of said hub bosses respectively, so as to prevent the junctions of said shell sections and hub boss from obstructing clamping of the blades by the full extent of the circumference of said shell, and clamping elements for drawing said shell sections together.

20. In a hub for aeronautical propellers, opposed complementary parts having, abutting tubular hub bosses for receiving a propeller shaft, and including outer substantially semi-cylindrical shell sections having registering inner peripheral grooves at their outer ends for receiving end flanges of propeller blades, there being a clearance between the edges of said shell sections adjacent the grooves thereof for enabling firm clamping of said flanges between said shell sections and each shell section being integrally joined at a limited portion only with an outer extremity of one of said hub bosses respectively, so as to prevent the junctions of said shell sections and hub boss from obstructing clamping of the blades by the full extent of the circumference of said shell, and clamping elements for drawing said shell sections together.

21. A propeller blade supporting hub comprising a body member having a bore therethrough 1 5 for receiving a drive shaft, a plurality of blade sockets radially disposed with respect to the axis of said drive shaft bore, said body member being split perpendicularly to the axis of said drive shaft bore and diametrically of said blade sockets, 139

a plurality of bolts extending through said split portions and co-operating nuts for clamping propeller blades in said sockets, and balancing weights carried by said bolts.

JOHN SQURES;

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