US1279742A - Variable-pitch propeller. - Google Patents

Description

S. D. MOTT.

VARIABLE PITCH PBOPELLER. APPLICATIQN FILED Nov.21`.1915.

Patented Sept. 24, 1918.

2 SHEETS-SHEET l.

WITNESS/:"8

S. D. MOTT.

VARIABLE FITCH PROPIELLER.

APPLICATION FILED NOV-'27'. I9I5- Patented Sept. 24, 1918.

2 SHEETS-SHEET 2.

SAMUEL D. HOTT, 02|."

Specification of Letters Patent.

a UNITED STATES PATENT OFFICE. Y

Passaic, Nnw zrnnsnnassreNon. or ONE-Hams` 'ro B. SULLIVAN, or ALLENDALE, NEW JERSEY.

Patented sept. 24, 191s".

Application led November 27, 1915. Serial No. 63,710.

struction, and more particularly air propel- 1ers such as used for propelling air-craft, and the partlcular object is to produce a variable pitchpropeller, but in practical manner. -Moe particularly. the object is to eiiect the desired result in a simple, strong and reliable construction capable of meeting the exacting requirements of aeroplane propellers and the like, roperly balanced as to adjustmentof pitc and changeable or variable in a degree suiiicient for all practical purposes, and at the same time light and reliable, and operable in. a convenient manner when in operation, to meet the varying conditions of starting and changed air conditions. To accomplish this result with a light construction of maximum strength, .will appear as one of the most important features of my invention. Particular embodiments of my invention are shown in the accompanying drawings, in which:

.Figure I is a part sectional view of the axis of the propeller shaft,A partdiagrammatic. p

Fig. II is the main shaft'removed from the structure.

Fig. III is an end view of a blade showingl ig. VI is a side view of the pitch adjusting mechanism in the duplex apparatus, at

'section VI-VI The main drive shaft -1 has mounted on it a hub 2 of a wire spoke wheel 3, havin a.

rim 4;.while the secondhub 5 with wireA spoke wheel 6, and rim 7 are likewise mounted on the drive shaft 1. Bletween the hubs A l is a bladepivot flange 8, to which blades 9-9 are attached with any suitable means such as the head 10.

The propeller blades are strengthened part way out from the center with a strap 11, With a hinged joint 12 firmly secured there to or integral therewith, which is secured to the other hinged member 13 attached by suitable collar or otherwise, to the wheel rims 4 and 7.

and. Within this sleeve is a rod 15. The

sleeve 14 has radial lugs 16, while the rod15 has at its extremity the enlargement 17 and integral. lugs 18.

The lugs 18 project throughy the helical slot 19 in shaft 1, and the lugs 16 project through the helical slot' 20, and in each c'ase the lugs pass through openings in the hubs `within, the drive Shaft 1 is a Sleeve 14,

2 and 5, respectively, the sides of these lugs 16 and 18 being slightly inclined so'as to iit snugly into theV slots 19 and 20, and slide readily in these slots.

Sleeve 14 and rodV 15, are secured at the A operable end to lugs 21-22. having threaded collars tllfroughwhich shifting screw 23 passes, which screw is supported in a rigid bearing 24, against axial movement, and has an operating hand wheel 25.

Byfthe turning of the hand wheel 25, as

shwn in the drawing, the lugs 21-22- are.

moved apart by means of the lthreaded rod 23,'and the attached sleeve 14 and rod 15 are the movement of the hand wheel 25 would gradually move the lugs so as t0 jpull'the supporting wheel hubs 2 and 5, toward each other, andas they move, the lugs 16 and 18 accordingly moved axially with respect to each other, which in turnproduces a movement of the lugs 16-18. Considering Fig. I,

19420, which have beenv given 'a predeterl mined helical pitch. v This movement of the hubs 2 and 5, axially along the drive shaft 1, so proportioned with respect to the slots 19-20, that a relative circumferential movement is given 4to the wheels 3.'and 6, in proportion tothe movement of the hubs on the shaft. By this slight circumferential" I relative motionthe necessary movement is `tion of the joints, oircumferentially, on the wheel rims 4 and 7, will thereby be changed to an Xtentn represented by the distance C and and this distance represents the-required relative circumferential movement,

. and thereby slight rotary adjustment of the wheels 3 and 6 with relation to the shaft to which they are splined orkeyed by the lugs 16 and 18.

It will thus be seen that the construction is one capable of adjustment by means of the turning of the hand wheel 25, by the operator of, for instance, an aeroplane, while the propeller is in operation, and by suitable proportioning of the hand wheel and the threaded or other parts, sufiicient power may be readily available to accurately and sensi tively adjust the pitch of the propeller without cramping of the movable parts, and without losing in any way the predetermined strength and support for the propeller, in allIpositions of adjustment.

. articular attention is directed to the use of the wire spoke wheels 3 and 6, which are a most important element of the construction. Wheels so constructed are known to give the strongest and lightest construction for articles of this character,-the tangential spoke with steel of high tensile strength combined with cold-drawn steel tubing of like high tensile strength, affords a structure which I have selected as pecnl-...f

iarly adapted to my invention.

By the arrangement described, the adjusting of the propeller pitch is effected by movement of points on the propeller some distance out from the center, and the relative size of 'v'heels 3 and 6 compared with the length of propeller blade, may even be such as to Support the sides of the blade at a point half wa resistance of the propeller blade. In any event having the support carried out a far eater extent than the ordinary hub, afords a' support for the propeller which for given strength is effected with lightness far beyond what has heretbfore been the practice.

The movement or driving of the propeller may be effected in any manner by the turning of shaft 1, by the gearing or chains, or direct coupling to motor,-any desired manner, being so optional that the driving ower has been indicated on the drawing, ig. I,

out or even approximating the center Lavar-ta symbolically by the word-Moten which will be understood to mean any desired or suitable driving means.

The light skeleton Wheels or tension spoke Wheels, may have their spokes made of Wire having a ribbon section or fish-shaped secr tion, to minimizev the wind resistance in their rotation, and such flattened spokes may in themselves be placed helically, thereby acting as small blades to assist in propulsion, so that in a sense the whole hub structure far from being a sourceof resistance, effects the desired result as to strength with an added advantage in efficiency of the entire propeller. v

In Fig. IV is shown, in part broken away, propeller shafts 26-27 driving a pair of propellers, the shafts being` supported in bearings 28 connected by transverse members 29. Any suitable propelling means may be applied, as at 30, to drive the shafts 26-27 and the propellers.

The coperatlng adjusting rods 15 and sleeves 14 are brought into a position so that the adjusting screw 23 may be operated by a bevel gear 3l, which in turn is operated by bevel p1nions32, on a common shaft 33 which is actuated b a hand wheel 34.

In this manner t e hand wheel 34 may be rotated, and through the gears and adjusting screw will relatively move the pairs of adjusting sleeves and rod 1415, simultaneously so as to produce a simultaneous variation inthe pitch of the two propellers operating as a pair.

In similar manner a larger number of propeller-s coperating in one machine may be adjusted simultaneously or in predetermined ratio. It is well known that ropeller blades are designed with a @sur ace accurately prescribed for given conditions of operation, and that a single blade surface' may not be equally efHcient when used or set at different degrees of pitch.

The variation of pitch however, is a desirable feature in certain conditions of operation, and the advantages gained are such as to make desirable means of pitch adjustment practical from the standpoint of strength and structure and adjustment,- which will all be realized in the practice of my invention.

Details of construction have been indicated in the particular embodiment herewith shown, in some respects symbolic or diagrammatic, whereas in practice details are modified to permit the roper' assembling or adjusting of Parts, andp as to these details of construction, many variations may be made in dimension or arrangement.'

Furthermore, the structure in general may be modified in many ways from the exact embodiments which I have herein yshown and specifically described, but what I claim and desire to secure by Letters Patent is:

termedate the hub and the radially outward end of the propeller, for ythe purpose described.4

- 2. A variable pitch propellerl comprising -a drive shaft, two supporting wheels on said drive shaft having axial movement thereon, means for slight rotary adjustment of said wheels, and 'means within said drive shaft `for effecting said' axial and rotary adjust'- ment, an operating mechamsm accessib e to the operator to adjust said hubs While said propeller is in motion, circular frames secured to and movable with said hubs, a plu- .rality of blades ha operation, to vary their p1 their butt ends pivotally xed adjacent t e shaft, and extending radially from said shaft and having articulated' connections from said circular frames at points intermediate their huh connection and 'radial extremity.

3. Variable pitch propellers for air-craft, comprising a lurahty of blades having a permanent ra 'al position with respect to the driving shaft, and havingmeans for slight rotary adjustment of the blade supporting-hub, with reference to the driving shaft` and means whereby an operator may adjust a plurality of said ropellers while in *lich uniformly.

4. An air propellercomprising a plurality of blades, a dri've shaft, pivotal means of sup ort of eachblade adjacent the drive sha driving hubs on said drive shaft on yopposite sides of the blade support, a wheel on each hub and articulated means of sup- November, 1915.

port for each blade at the periphery of each wheel, means for va -the distance between said wheels where ya variation of pitch of the propeller'blades is effected, an operating means whereby said variation may be1 1effected during the driving of the prope er.- l 5. An aeroplane propeller, comprising a plurality of blades extending radially outward from a drivin shaft, a hub connection for the inner end o each blade adjacent the shaftz two relativel movable hubs on opgansite sides of said b ade connections, circ r frames carried by said hubs and having articulated connections near their periphery for engagement with the blades intermediate their hubs and ends, means for mo said frame hubs whereby a uniform change 'fin the pitch of the propeller blades is simultaneously effected. v

6. An aeroplane propellercomprising a drive shaft, a plurahty of blades extending from adjacentthe drive shaft radially outward, rsubstantially at right angles to the shaft, and havin a means of support adjacent the shaft, oo ars surroundin the shaft on the opposite sides ofthe bla e sup orts and carrying circular ramesrespective y, of "a radius less than the radius of the propel- 1ers, and attached to the propellers intermediate their hub and tip, relatlvely nearer the hub, whereby the most effective reaction area of said blades is clear of any adjacent frame members.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses, this 26th day of SAMUEL n. Morr. Witnesses:

HERMANN F. 'Ci-nvm, H. Muormonn.

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