US1444959A - Ihghouse - Google Patents

Description

D. A. DICKEY.

Feb. 13, 1928.

COMPOSITE PROPELLER AND METHOD OF MAKING THE SAME.

2 SHEETSSHEET 2.

FILED DEC. 30, I918.

INVENTOR Dan/kl A. D/M'ey WITNESSES: I

/ ATTIDRNEY Patented Feb. 13, teas.

v 1344,95, FATE NT DANIEL ADAM Dion-Er, orwrnxmsnuae, rEmvsYLvANrA, risers-Non To W menousn nrnernrc & MANUFACTURING. COMPANY, .A conronarron or runn- SYLVANIA.

coivrrosrrn rnornnnnn AND'AMETHOD "or MAKING THE seine.

Application'filed December so, 1918 seriaijnbyeesn a. i

To all whom it may concern: Be itknown thatI, DANIEL A. DioKnY,

a citizen of the United States, and a resident of'Wilkinsburg, in the county of Allegheny new and useful Improvement in'Composite Propellers and Methods of Making the Same, of which the following is a specifica- '"tion.

invention relates to air screws and more particularly to propellers for aircraft, and it has as one objectthe provision of propeller of the type comprising a body formed of superimposed layers of fibrous sheet material impregnated by, binder, of

suitable character, which has been properly i hardened and compacted.

Propellers of such character have been ,p

previously proposedin which the superimposed layersof sheet material were disposed in planes substantially parallel to the axis of a propeller hub. In such construction,

however, those of the layers, making uplthe body, which extended completely from end to end were disposed outermost'where they areniost exposed toinjury or weakening strains during theuse of the propeller.

As a'means for overcoming this objection,

as well as for otherreasons which will be hereinafter set forth, one of the primary objects of my invention consists in the construction of a propeller, comprising superimposed layers of sheetmaterial united by a binder, in which the several layers are disposed in planes substantially parallel to the faces. of the propeller hub, that'is, substantially perpendicular tothe axisof the hub,

so that, such of the layers" as extend through out the length of the propeller will be the cutting the several layers, of dilierent sizes and shapes, required to form the propeller body. l

Still another object of my invention consists in providing an improved means for handling the layers, constituting thebody of the propeller, and for'assembling them in proper position within a mold to insure uniable manufactured-composite fibrous sheetv Withthese and other objects in ,view, my

invention will bemore full "described ill s- 5 and State of Pennsylvania, have invented a yd i u 6O 1n the claims.

-Fig. 1 is a front elevation ofapropeller,

constructed in accordance with my invent on; 1g. 2 aside elevation thereof; Figs. *0 and 4 are plan views of layers. ofsheet mav v ter al cuttoftheproper shapes and sizes to be employed lIl' certain portions offthe pros peller, the portions which these particular layers will occupy being indicated by the l section lines ill-J11 and IV+IV of'Fig.

Fig. 5, is a diagrammatic transverse, sectional view trating the layers of sheet materialemployed and of positioning them for molding; Big; 6 is aplan through a propeller blade, illusw method of handling the several view further illustrating the manipulation of the several layers as they are'placed 'ina mold. j 1

In practising my invention, I may cut suitmaterial, such as duck or other woven material or paper, cotton batting or other matted material, to provide; a sufficient number of layers of the proper size and shape. I may then impregnate these layers with a suitable binder, such as a phenolic condensation product shellac, or some shellac substitute, such as acopal or a casein composition, and thenplace the layers in proper superimposed position in a moldof, suitable size and shape 9 in order thatthe assembled body may be compressed, hardened and cured. 40 innermost ofthe layers constituting the pro- Preferably, however, the sheet material is impregnated with abinder and dried suliiciently to drive oft any solvent employed, without affecting thebinder, before it is cut into the desired layers or laminations, asits handling is thereby greatly facilitated.

Any preferred. method of obtaining the requisite patterns for "cutting the several iayers from the sheet material may be em-.

.ployedbut I have found that the most desirable way of obtaining these patterns is to develop them as sections formed by passing a plurality of parallel planes through a propeller model parallel to the facesof its hub.

Obviously, when a suitable number of layers have been cut. from patterns thus developed and have been superimposed, in proper sucbe cured orliardenedfby suitable means, de-

p nd sy empi yeidi Referri'ngmore particularly to ,the development oif the p atterns,.it Will be apparent that, in s uch as each pattern will varyslightly, both inshape and size, tromthe other patterns, the most, natural method, from atheoretical viewpoinu would be to pass 'asmany sections through the model propeller and, consequently, to develop as many patterns as. there are required layers a large extent, upon the binder fof jsheet materialiin the finished propeller. Inasmuch, however, as when even v heavy 30' duck fis employed, several; hundred layersare necessary to formal single propeller, it is evidently impossible/{from a practical. manufacturing standpoint, to follow this theoretically desirable method. I. have, therefore, conceived What,as opposed to the.

' theoretical method, may Well be termed they model: at uniform intervals and parallelito sov step method in which eachpattern Will serve as'a guidefor thecutting of a plurality of associatedlayers of sheet ,material.

According to this" step method, Ipass a suitable numbero fplanes, as, for example, twenty, for a propeller having a hub, four, inches in thickness, through a, propeller the faces of the h ub of the modeland develop,

1 patterns trom the sections thus, indicated.

Fore'Xample, in Fig. '2 Ihave shown Where two sections through theypro'peller which,

for present purposes,,may be considered as a model; maybe taken, and, in FigsQl and 4,

l have indicatedlayers 2 andf3 cut from patterns derived 'lroin passing planes through the sections indicated. Obviously, when "a plurality of; sections are-passedthrough the propeller at uniform intervals, a plurality or patterns of this character, varying materially in some instances in both shape and size, will be provided.

employing each pattern as a-ineans for cuttings pluralityof'layers of sheet nun terial and.superimposing the layers cut "ironithe same pattern, in each instance, a

plurality of ,QlOllPS or sections ief material may be provided, as shown in Fig. 5, and r thcsegroups of material may then be supen riouslayers fall substantially in asur' corresponding,1n curvature, to thejsuri imposed to approximate roughly the shape of the desired propeller.

Preferably, for thesake of convenience in handling and consequent rapidity of manufacture, I prefer to out all ofthe layers of any one patternsimultaneously from a body comprising a plurality of superimposed layers of sheet material. To facilitate this,

I may treat the sheet material'in a manner fullywdisclosed.in a copending application filed by me on Dec. 30, 1918' and bearing Serial Number 269,950.. there, disclosed, a suitable number of" layers of, im-

pregnated sheet material are superimposed between protective layersfof untreatedisheet material, and the body or plate th'us assembled is subjected to, suiiicient heat and pres-Q sure to cause adhesionbetween the seyeral,

binder utilized. Preformed plates thus vided may Well be utilized in practising my present invention, a group's orlsection, 4: of the.

desired shape and sire, in eachinstancqbemgcut fro'm'a, preformed plate by any suitable means as, for example, a band saw.

layers without affecting the propertiesofthei. 1 I

When the necessary, number otgroups of material, correspondingto the ,numberiot iatterns em aloyed have been formed in this, l p a v r a manner, their protective, coatings maybe peeledjoff to, expose clean, rough surfacesv su table for molding, and the various groups,

or sections may be superimposed inpr'oper" order in a mold, in the relative positions shown in the upperright-hand portion of Fl 5;, 5, and there subjected vto heat and. pres; surefto cure thefbinder andcompress and harden the entire assembled body.v the sections are not' ,too thick, the, impregnated sheet material will fioiv oriyield sufficiently injthe heated mold to fill ,in the angular spaces between the edges of the adjacent, sections, whereby] a propeller havingv a uniiiorrnly smooth surface will be provided I have found, however, fromactual experience, that more uniform andsatisfactory results may be obtained by following. the method bestdisclosed in they lOWerlQft-hand portionoit' ig, 5 andin 6. By, the,

method hereshoivmthe several layers 540i eaeh preformed plate section 4: are separated trom each otherfas the section]. isibeing, placed in the mold, and the layers thus",

separated are fanned or spread out;

clearly shown in Fig 5 and .6, thatm/then the several-fanned sections have been supp imposed n proper order, the edges i the .Vll:

of the desired propeller By thisarrang eg ment, practically ,all necessity for flow oi f material in the mold. is obviated, and a more uniform propell as regards v I strength and 'bal nee, may, be) obtained,

, Preferably, the various sections employed may be formed with a central shaft-receiving opening 6 in order to avoid boring through the hardened propeller afterit'has: been molded, a suitable stud or mandrel constituting a part of the mold, seating injthese alined openings during the molding. A suitable lreyway may be cut in the hub of the propeller after it is molded, and the propeller may be keyed directly upon its shaft or a metallic hub 7 of any desired type may be employed.

By the foregoing method, the duck or other sheet material is assembled in a logical manner for pressing. at the hub as Well as at all portions of the blades, the fibres run continuously throughout the length of the propeller and, as the several layers are cut symmetrically, an accurately balanced pro peller body results.

vVhile various sheet materials may be employed and also any one of several binders, I prefer to utilize some heavy (Woven material, such as duck, impregnated With a phenolic condensation product, such as bakelite, as a binder. This material is particularly desirable as a properly shaped body composed of it may be cured in a mold, by subjecting it to heat and pressure, toi orm a hard, solid, somewhat resilient and substantially insoluble and infusible propeller. Furthermore, a propeller formed of this materialis non-inflammable, is not affected by moisture, oils, Weak acids or alkalis and Will not Warp because of climatic changes. a

As many changes in the materialemployed and in the particular methods whereby the material may be provided in the desired form for molding are possible, I do not Wish to, in any Way, restrict m invention except as indicated in the appen ed claims.

l claim as my invention:

LA propeller comprising layers of man- .ufactured-composite fibrous material and a hardened binder, the layers being disposed substantially parallel to the faces of the hub. I

2. A. propeller comprising superimposed layers of manufactured-composite fibrous material and a hardened phenolic condensation product as a binder, the layers being disposed substantially parallel to the faces of the hub.

3. A propeller comprising superimposed layers of Woven sheet material impregnated and joined by a hardened phenolic condensation product as a binder,the layers being disposed substantially parallel to the faces oi the hub.

4. The method of forming a propeller which comprises impregnating fibrous sheet material with a binder. cutting layers of suitable shapes and sizes from the treated sheet. material, superimposing the layers in proper order relative to their shapes and sizes .to build up a body of approximately propeller outline in which the layers are disposed 'substantiallyfparallel to the faces of-the hub portion and curing the body thus built upzunder pressure. i i

5. Themethod of forming a propeller which comprises impregnating fibrous sheet material With a phenolic condensation product as a binder, cutting a plurality of layers from the sheet material of proper shapes and sizes, superimposing these layers. in proper relative positions, accordingto their shapes and sizes, to provide a body substantially conforming in shape to that of a propeller and in which the several layers are disposed substantially parallel to the faces of the hub portion of the body and subjecting the body to heat and pressure in a mold to compact it and harden the binder. r

6. The method of forming. a propeller which comprises superimposing layers of impregnated sheet material between protective layers of unimpregnatedsheet material and slightly compressing and heating the plate thusformed to cause adhesion between the several layers, cutting sections of proper shapes and sizes from the plate thus formed, removing the protective coverings from the sections thus provided superimposing the sections in proper order With regard to their shapes and sizes to provide a propeller-shaped stack and subjecting the stack thus provided to heat and pressure to compact it and harden its binder.

7. The method of forming a propeller Which comprises forming compound layers of suitable shapes and sizes, each of which comprises a plurality of superimposed sheets of impregnated fibrous material adhering slightly to each other, superimposing the compound layers thus formed and in the meantime separating the various sheets of the layers and fanning or spreading them, whereby a substantially propeller-shaped body is provided, and subjecting the body thus provided to heat and pressure in a mold to compact itand harden the binder.

8. The method of forming a propeller which comprises providing a plurality of layers of suitable shapes and sizes, each of Which comprises a moldable plate section of superimposed sheets of fibrous material impregnated with a phenolic condensation product in an uncured state,'superimposing the several compound layers in proper order relative to their shapes and sizes, separating the several sheets of the layers and swinging them laterally or fanning them shape of a propeller, and subjecting the sureiative to each other, whereby the supershape of a propeller, and subjecting the superimposed compound layers to heat and pressure, in a mold to compact them and harden the binder. a

9. The method of forming a propeller Withutheirshapes andsizcs to provide a subs'tantially propeller-shaped body, each: of

thc layers comprising a moldable compo- SltlOIl havlng a ,phenohc condensation prod uc tcgfisi a binder, and subjecting the bcdy thus assemblcdzto hcatandl pl8SSL1l6 iIl-IL mO1dto compact itzmd harden thcrbinder.

' In testimony whereof, I have hereunto: subscribed'my. namecthis 21styday ofiDec.

DANIEL ADAM 'DICKE Y.

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