US2057924A - Method for fabricating propeller blades and the like - Google Patents

Description

Oct. 20, 1936. w SMlTH 2,057,924

METHOD FOR FABRICATING PROPELLER BLADES AND THE LIKE Filed 00tl, 1929 9 Sheets-Sheet 1 Q 5 a; g N e Q \h 1 N N I V I I Oct. 20, 1936. J, w, s T 2,057,924

METHOD FOR FABRICATING PROPELLER BLADES AND THE LIKE Filed Oct. 1, 1929 9 Sheets-Sheet 2 Q Q INVEN TOR T NEY V I1. 62m

J. W. SMITH METHOD FOR FABRICATING PROPELLER'BLADES AND THE LIKE F-iled Oct. 1, 1929 9 Sheets-Sheet 3 INV TOR.

Oct. 20, 1936. w sMlTH 2,057,924

METHOD FOR FABRICATING PROPELLER BLADES AND THE LIKE Filed Oct. 1, 1929 9 Sheets-Sheet 4 Jig. 5

m ww- Oct. 20, 1936. J. w. SMITH 2,057,924

METHOD FOR FABRICATING PROPELLER BLADES AND 'THE LIKE Filed Oct. 1, 1929 9 Sheets-Sheet 5 aw A ORNEYS.

Oct. 20, 1936. J. w. SMITH 2,057,924

' METHOD FOR FABRICATING PROPELLER BLADES AND THE LIKE Filed Oct. 1, 1929 9 Sheets-Sheet 6 fi ORNEYS.

Oct. '20, 1936. J. w. SMITH 2,057,924

METHOD FOR FABRICATING PROPELLER BLADES AND THE LIKE Filed Oct. 1, 1929 9 Sheets-Sheet 7 IN VEN TOR.

J. W. SMITH Oct. 20, 1936.

METHOD FOR FABRICATING PROPELLER BLADES AND THE LIKE Filed 001;. l,

1929 9 Sheets-Sheet 8.

M INVEN 0R.

ATTORNEYS.

Oct. 20, 1936. J. w. SMITH 2,057,924

METHOD FOR FABRICATING PROPELLER BLADES AND THE LIKE Filed Oct. 1, 1929 9 Sheets-Sheet 9 Patented a. .20, 1936 PATENT OFFICE DIETHOD FOE FABRICATING PROPELLER BLADES AND THE LIKE John W. Smith, Philadelphia, Pa. Application October 1, 1929, Serial No. 396,481

My present invention relates to a machine and method for making aeronautical propeller blades, fabricated by combining three fundamentals, forging, longitudinal .rolling and simultaneous twisting as a completed stage .of fabricating a metal propellerblade and is applicable to and an improvement upon my co-pending U. S. pat

ent application Serial No. 289,052, filed June 28, 1928, issued as Patent No. 1,840,059 on January 5, 1932, entitled Rolling machine.

f The specific type of blade herein referred to is fabricated from aicomparatively short billet and within the completed forging and longitudinal rolling period andis distinctively diiferent from the heretofore used method of forming and twisting or shaping propeller bladesafter the forging period or after the cross sectionalarea and length have been prepared. a Attempts to fabricate propeller blades by form; ing, shaping and twisting prepared metal blanks after the required cross sectional area and length have, been prepared by forging or rolling has resulted in structural weaknesses.

There are two important factors to be con-- sidered 'in making the best possible metallic aeronautical propeller blade suitable for modern high speed performance.

The first factor relates tothe specific type of blade. 30 The second factor relates to the apparatus and method of fabricating the specific type. of blade. two factors cannot be properly explained when treated as separate'subject matter.

.The above two factors must be combined in 35 the manufacture ofthe best possibleaeronautical propellers; v

In my other application Serial No. 289,052 I showed a machine inwhich it was necessary to hand-tilt, or set the die l5at the time when the 40 blank was inserted.

. I'now. employ an automatic means in the form of small auxiliary rollers 63, Fig. 7, for positively controlling the tilting of the die l5 during the I initial pass or passes and before'the gauging V 45 rollers la and lb make contact with the rails lib of the tilting die. p

Improved means, Figs. 4 and 6, comprising rod 44, crank 45a, rod 48, and racks llaand 41b, are herein employed for adjustably settingthe an- 50 nulardie l4 toward the other die as a substitute for the setting means controlled by the hand lever II in the'machine of my other application. I

As a modification I retain the fundamental which combines the forging, rolling and twist- 56 ing operation of my other machine, but substitute for the longitudinally reciprocating tilting die a second annular die and axially twist the metal blank instead of said die, or tilt the annular die and hold the blank.

These and other advantages of my present in- 5 vention will appear from the following specification and drawings showing a preferred embodiment.

In these drawings:

Fig. 1 shows a comparatively short metal blank 10 suitable for forming two blades. Fig. 1B is a cross section of same.

Fig. 1A shows an initial forging operation applied to one of said blanks.

Fig. 2 is an end view combined with a plan view of the finished blade, the latter also showing cross sections of the blade taken at various positions' along its length.

justing means therefor, the latter operable to vary the extent of the forging movements of the annular die.

Fig. 6 is a transverse vertical sectional view partly in elevation through the machine of Fig. 4 showing 'the driving gears of the machine, the means for controlling the extent of the forging movements of the annular die, and the means for operating the walking beam which reciprocates. the tiltable dieduring rolling period. 40

Fig. 6A shows means for setting for first or second pass.

Fig. 7 is a transverse vertical sectional view partly in elevation on a larger scale than Fig. 4

showing the annular die and the transversely tiltable longitudinally reciprocating die in position for the final passes with a section of the propell blade in the die cavity. v

Fig: 8 shows crank pin adjustment for second pass. I I

Fig. 9. shows tension adjustment for gauging rollers. I

The remaining Figs. 10 to 16 show the double annular die modification of the machine asfollows:

Fig. 1c is a view similar to Fig.4 except that an annular die has been substituted for the iongitudinally reciprocating die and shows the means for supporting and axiallytwisting the Fig. 12A is a plan .view of the turning mecha-- nism of Fi 12.

Fig. 13' a sectional view partly in elevation through the two annular dies and their related parts.

Fig. 14 is an end view of the annular dies partly in section and their relating; parts. Fig. 15 is a transverse vertical sectional view partly in elevation on a larger scale through the pitch generating mechanism.

Fig. 16 shows a substitute for the means of Figs. 13 and 14 by providing a tilting mounting for one of said annular dies.

'Fig. 1'? shows a further substitute for the means of Figs. 13 and 14. a I will now describe the specific mechanism as a typical example for forging, rolling andsimultaneously twisting the metal blank into the fabricated article but of course without limiting my invention to the details of said embodiment except as required by the appended claims in view of the prior art. The same reference numerals indicate corresponding parts throughout.

The base 60, Fig. 4, of the machine supports col- .umns 68:: connected at the top by cap-yoke 60b.

This supports the toggle means hereinafter described for giving vertical forging movement to the head 58, the latter having sleeves 58a slidable on the columns 69a. This head 58 supports slightly higher (Fig. 7) than the sidewalls [5a of the die cavity to permit the excess metal from the blank to squeeze from between the annular 'die 14 and the die l5'into the aforesaid flash re-.

4 .cesses 6. The surface of the rails l5b and of the blade tobe formed.

die-cavity walls l5a lie in an undulating twisted plane corresponding to the angular twist of the The die I5 is mounted for longitudinal reciprocation under the-annular die l4 and for simultaneous lateral tilting movements so that the twodies cooperate on a plane which follows and ultimately is identical with the above described twist in the rails and die.

. Extra heavy toggle link construction is used to secure the necessary vertical forging pressure of the annular die l4 against the metal blank and the lower die l5. Thus the described cross-head 58 supporting said annular die is supported'by toggle links 38a, and 36b, pivoted to the rockers r 31a and 3") by pins 36, the links being pivoted to the crosshead by the pins 31. The rockers 3H: and 3 b are connected by link 38. The means :for

operating said toggle comprises an armed rock-r shaft 53, Fig. 4, suitably journaled in the machine housing 8! and 82 and having a left-hand arm for mounting the cam roller 49 and a right-hand arm connected by link 52 with the upper parts of the rockers 3la and Nb. When the circular faced cam 50 on the anti-clockwise rotating shaft I0 bears against the aforesaid cam roller 49,

Fig. 4, it rocks the armed rock-shaft 53, pulls down on the link 52 and straightens the toggles which forces the annular die M with a powerful forging movement into the metal blank. Then said annular die l4 remains in said down position while the walking beam 56 imparts reciprocating movement to the die I5. Said crosshead is not released until the lifting cam 5| carried by cam shaft 10 contacts against the cam roller 56 mounted on an arm of the rock-shaft 53. By

pushing upwardlythe link 52 the toggles are unlocked and the roller die I4 is withdrawn from 'die l5.

Die i5 receives reciprocating movement through walking beam 56 hinged on pin which is securely fastened into main housing 8| as shown in Fig. 6 and Fig. 3.

Crank pin 55c is journaled in a shoe slidably guided in walking beam 56 as in my other application.

Crank pin 55c is a part of slide 55a (Fig. 6) mounted on the rotating cam shaft 18.

' Adjusting screws 55b control the adjustment of crankpin 550 shown in Figs. 4 and 6, and provide for the required length of travel for making long or short forgings. I

It will thus be seen that when the shaft vIll is driven, the walking beam 56 will be oscillated re-.

sulting in the longitudinal reciprocation of the die carriage 59 along with the cradle 20 and the rest of it being indicated merely by the broken Adline 56 so as not to obstruct the drawings. justable link 51 connects walking beam 56 with reciprocating carriage 59.

The walking beam construction provides an extended time element of 235 (compare Fig. 2B) for the rolling stroke and a short time-element for a quick return'stroke of 125. I

Rack 59 in Figs. 4 and 7 is hinged by link 88 to adjustable stud mounted in arm 89 which is fastened to and reciprocates with reciprocating carriage 59.

Rack 59 reciprocates in' gear case 58a (Fig. 7) and is in mesh'with gear wheel 64 which is secured to annular die shaft 8 by bolt 81. Annular die It is secured to shaft 8 by key 69. The herein described mechanism establishes a registration between the reciprocating die l5 and annular die- I 4 and provides for a vertical forging movement during the rest period of the reciprocating die i5.

Two or more automatic passes of different forging'extent are provided and are made to function through the following mechanism.

In Figs. 4 and 5, toggle rockers Sla and 3lb are mounted on shafts 35a and 35!), supported at .either end in eccentric bushings 34 (Fig. 5) which are journaled in supporting cap rocker 39 and securely held to shafts 35a. and 35b.

Lever 48, shown in Fig. 5 (center line of same is. shown in Fig. 4) is secured on shafts a and 35b,

and may bemoved from position 42a to 421) shifting center from 53a and 59b. thus automatically setting the machine for the first and second pass respectively. thus automatically setting the pass during lifting period-C, shown in diagram Fig. 23 at a time when there is no pressure on the dies.

In Figs. 4 and 6, shifting link 48 is shown to be hinged to cam rocker 53. Cross pin 4% forms a part of link 48 and operates in guide slot.69 (Fig. 6A and Fig. 6) and is used to shift pin 48b from rack hook 41a to 411), and vice versa, the shifting medium is represented by lever 61. Tumble shaft 68 is pivoted into guide 69 as shown in Fig. 6A.

Teeth on racks 41a and 41b shown in Figs. 4 and 6 engage pinion 46, secured to crank shaft 450. When rack 41a is pulled down as herein described crank pin 45 will be in position for the second pass. When rackjl'lb is pulled down crank pin 45 will bein position shown in dotted lines at 45b for the first pass. Link 44 transmits from crank pin 45 to lever 40 the required movement for the first and second pass.

Fig. 8 shows how crank pin 45 is slidably fitted into the crank end of crank shaft 45a. Adjust- I the crank pin 550 is passing the neutral point-of the stroke, said crank pin rotating in anti-clock ing screw 45b is used for setting the crank throw to suit the required amount of reduction for the second pass.

In Fig. 4 if the throw of crank pin 45 is increased the are between 53a and 53b will be increased. If thethrow of crank pin 45 is diminished, the are between 53a and 53b will be diminished.- If lever 61' is not moved, the pass will be automatically repeated.

In most cases the second pass would be repeated as the final pass. I 1

Fig. 7 shows the gauging rollers 1a and lb bearing hard against the die rails l5b, which represents a requirement for the final pass in rolling to gauge thickness and unit weight.

Auxiliary. rollers 63 are mounted in suitable sockets in brackets 52a and 62b secured to the main housing 60 and control the tilting of the die l5 when the gauging. rollers la and lb are withdrawn.

A large forging machine has considerable spring to be considered.

The second pass may result in the gauging rollers la and lb being forced away from the rails l5b, where the blade is widest, thus requiring a repeating pass to finish to gaugev thickness.

Fig. 9 shows the length of link 44 to be adjustable by means of right and left hand screw threads. This adjustment is made use of to secure the proper tension for gauging rollers la and lb.

The described shifting of the arm 48 from one rack to the other may be made either by hand or automatically.

Fig. 7 shows how the die cradle 20 along with the die I5 is free to tilt to dotted line positions 6M and Bib to conform to the required pitch angles throughout the blade profile. The face of the die I5 is preferably machined on a special pitch-generating miller as shown in my U S. patent application, Serial No. 268,208, filed June 4, 1929.

The diagram,'Fig. 23, indicates a typical example in the operation of my machine of vertical forging and longitudinal rolling divided into four periods A, B, C. and D.

Period A shows the vertical forging movement to be substantially completed within the dwellperiod of walking beam 56 at the moment when wise direction. The rolling period '3 then takes place during 235 out of one complete rotation or cycle.of the crank pin. 'At the finish of the longitudinal rolling movement, the annular die I4 is raised from the work, this being the lifting period 0 in the diagram. Within the full lift period D the machine may be stopped, if desired,

by moving hand lever 18, Fig. 6, thus disengaging the clutch l6. Atthat time the annular die M will be raised sufliciently high to withdraw the finished blade and a new blank l0 may be inserted.

Fig. -1A shows the blank in position between the two dies l4 and I5. The vertical forging movement has forced die M in the direction of arrow l3 for the first pass. Space l2 between dotted line of annular die I4 and reciprocating die l5 represents the amount of reduction left for the second pass.

The stop is serves to locate the blank with relation to the dies and it also obstructs the flow of metal toward the hub end of the blank during the forging operation. The blank is gripped by causing the jaws Ilia and llib to be forced into the blank.

This gripping takes place during the forging movement as follows: Shoulder 22 on roller l4 forces gripping jaws I61: and llib to full grippin position as shown in Fig. 3. 1

Handle l'lb is a means for unlocking toggle I and l8b and also lifts the forging out of the die I 5 by imparting a movement to l6a and lib shown by dotted lines. Any suitable means can be used for'grlpping the blank at its near end.

I prefer to use this character and form of blank although it will be understood the same is not strictly essential. In other words, the proper distribution of the metal throughout the blank to form the blade by my method and machine is secured, preferably by sawing it off on an incline asshownat H in Fig. 1.

In this application as in my Patent No. 1,840,059, the metal is urged in a longitudinal direction at the moment of deforming, and each rolling pass starts at the required pressure and this required pressure is maintained throughout the rolling period. I

Each pass starts off with a vertical die forging movement for preparing theheavy section of the blade at the butt end of the blank. Upon the completion of the verticalforging movement and without releasing it, a longitudinal rolling movement takes place at the required pressure extending lengthwise of the bar, thus preparing a longitudinal grain fibre in the blade structure with a simultaneous shaping and twisting of the blade. By my method and machine the finished blade, Fig. 2, compared with the blank Ill is considerably elongated, preferably so that the grain fibre'is extended longitudinally in the ratio of about one to'three. The zone of the blade subject to the highest strains will possess the most extension of grain fibre.

The above process of forging, rolling and twisting prepares in the blade the very best physical properties."

The face of the annular die I4 is shown channeled at Ma to prepare the upper face of the blade during the forging and rolling operations. I he metal of said blank is squeezed and-rolled down into the cavity of the die l5. These forging and rolling passes are repeated until the die forging movement of the annular die completed and the machine about to begin the second pass rolling movement. This pass may be repeated as a final pass.

It will be seen that the described method and machine rolls the blade profile from a comparatively short billet, establishing the width, thickness, length and twist as a simultaneous operation. This is distinctively diiferent from the prior art methods of preparing the angular twist of the blade after the length and cross sectional urea has'been prepared, said prior art methods resulting in a comparatively inferior finished blade.

My application Serial No. 289,052 has the equivalent vertical forging and longitudinal rolling movements, the operation of same was explained in connection with a specially prepared short blank requiring considerable longitudinal rolling and only a slight amount of vertical forging.

This invention is herein further explained in connection with fabricating propeller blades from plain round bar material which is less expensive.

The vertical forging movement is herein used to eliminate the necessity of previously shaping the blank at the forging zone between lines 24 and 25 Fig. 2.

Figs. 2 and 2A show one type of finished blade adapted to be fabricated by my method and process. The round portion between the lines 23-24 is preferably finished by machining the blade. The zone between the lines 2425 is die forged. The zone between line 25 and the end 26 is die. rolled to gauge cross section and unit weight including angular twist. Forging, rolling and simultaneously twisting by using double annular dies Fig. 10 makes use of the same fundamental vertical forging and horizontal rolling as shown in Figs. 1 to 9 inclusive, by substituting annular die I50 for horizontal die I5. Therefore, no further description is considered necessary.

Figs. 13 and 14 show the equivalent rack mechanism used for the registration ofv said annular dies.

Fig. 14 shows 59a and 59b to be hinged on wrist pin I09 mounted in reciprocating carriage IIIl.

Connecting link 51 is also mounted on wrist pin I09 imparting motion from walking beam 56 to reciprocating carriage IIIl.

Annular die I50, substitutes reciprocating die 65 shown in Figs. 7 and 4.

Fig. 16 shows annular die I 5d mounted in nonreciprocating cradle 20a which is seated in main housing; in this event the pitch'angle is generated on the annular 'die I5d, and would eliminate the use of pitch generating mechanism shown in Fig. 11. Gripping jaws H3 would be required to reciprocate without rotary motion. 'In this event I25, Fig. 11, would be set parallel to the reciprocating path, as shown in dotted line I25a.

Fig. 17 shows annular dies .I5e and Me to have the pitch angle generated 'onthe face of both annular dies,in this modification annular diesare not tiltablymounted and would be used with a non-rotating gripping mechanism for holding the blank. Q

The above annular dies have milled in their faces the blade profile.

The required pitch -is generated by rotating the gripping jaws with the following mechanism in the herein described manner.

- Blank III (Fig. 1) is firmly held between rip- Pins jaws II3 pivoted on pins II3a as shown in Fig. 10.

T ggle links I I4. and rocker 5 are actuated by piston I" through link IIG.

Gripping jaws H3 and rocker II5 are mounted in sleeve I I2, which is free to rotate in reciprocated housing IIII.

-Spur gear H8 is mounted on sleeve H2. and engages with pinion II9 which is fastened on pinion shaft I20. I

' Bevel pinion I2I is mounted on pinion shaft I20 and engages bevel gear I22 which is bolted to pitch generating arm I24 as shown in Fig. 10 and Fig. 11. Generating slide I25, Fig. 10, is adjustably mounted on arm I24 by means of pivot bolt I23 and bolt I28 in slotted hole I33.

Bracket I3I is fastened to main frame 63 for supporting cross bar I26 in which'shoe I2I is pivoted, as also shown in Fig. 9.

Housing III is provided with a pair of tru'nr nions I08 and reciprocates with carriage IIII.

Studs I09 are mounted on reciprocating carriage I I 0 to which forked link 51 is hinged and is reciprocated by walking beam 56.

Racks 59aand 59b are also .hinged to the studs I33 and are actuated by the same motion.

Figs. 13 and 14 show how racks 53a and 53b engage timing gear wheels 64a and 54b respectively. The annular dies I4 and.I5c are securely mounted on shafts 8a and 81). Gear wheels 34a and 64b are securely mounted on shafts 8a and Rocking shoe 4 in Figs. 13 and 14 provides for the swinging of rack 59b during vertical forging movement of annular die I4.

Fig. 1-2 shows a modified movement which may be substituted for the pitch generating movement. Rocking head I3'I is secured to bevel gear I22. Actuating link I33 is mounted on stationary cross bar I3I.

The rocker head I3'I has been rotated from pivot point I38 to position I39 at the end of-the stroke after the completion of the rolling movement.

Link I33 may be set to angle I34 by hand operated handle I35 for returning rocker head I31 to normal position thus causing gripping jaws II3 to receive right angle turns at the completion of each pass, making it possible to. roll various tapered or special shapes.

I claim:

1. The method of making a propeller blade, comprising rolling a billet of metal into rough blade shape l'v a series of complete rolling passes from the I001. portion to the tip portion of the blade, thereby creating flow lines conforming to the contour of the blade, and completing the shaping of the blade by operations maintaining such fiow line structure.

2. The method of making a propeller blade, comprising deforming a billet of metal into rough blade shape by the repeated application of a deforming force progressively advancing from the root portion to the tip portion of the blade, thereby creating fiow lines in the metal conforming to the contour of the blade and confined within a deforming force to the metal, progressively advancing the point of application of force from the root portion to the tip portion of the blade, progressively applying the required force from the root portion to the tip portion of the blade to gradually refine the grain structure throughout the length of the blade with a of grain size contrast and to form fiow lines conforming to the contour of the blade, and completing the shaping of the blade by forging operations without increasing the grain size contrast or destroying the fiowlines.

4. The method of making a propeller blade, which consists in rolling a billet of metal to prepare longitudinal flow lines in it, rolling said billet into rough blade shape by a series of complete rolling-passes fromthe root portion to the tip portion of the blade, thereby creating flow lines conforming to the contour of the blade, and completing the shaping of the blade by operations maintaining such fiow line structure.

5. The method of making a propeller blade, which consists in preparing longitudinal flow lines in a billet of metal by rolling, deforming said billet into rough blade shape by the repeated application of a deforming force progressively advancing from the root portion to the tip portion of the blade, thereby creating flow lines in the metal conforming to the contour of the blade and confined within the blade, and completing the shaping of the-blade by operations maintaining such flow line structure.

6. The method-of making a propeller blade, which consists in preparing longitudinal fiow lines in a billet of metal by rolling, gradually deforming said billet into the shape of a tapering blade by applying a deforming force to the metal, progres'sively advancing the point of application of said force from the root portion to the tip portion of the blade, progressively applying the required I force from'the root portion to the tip portion of the blade to gradually refine the grain structure throughout the length of the blade with a minimum of grain size contrast and to form fiow lines conforming to the contour of the blade, and completing the shaping of the blade by forging operations without increasing the grain size contrast or destroying the flow lines.

7. The method of fabricating a propeller blade and the like from a comparatively short metal blank, which consists in subjecting said blank to an initial forging operation, urging the metal in a longitudinal direction at the moment of deforming as a preparation for longitudinal rolling, subjecting said blank to longitudinal rolling, and

simultaneously twisting the blank conformably to the axial twist of the blade, whereby the physical properties of the blade are improved and a longitudinal fiber structure is incorporated therein.

8. The method of claim 7, further characterized by repeating the cycle of operations therein set forth to further improve the physical properties and secure unit weight and precision in the finished article. 1

9. The method of fabricating propeller blades and the like, which comprises applying a forging operation near one end of a metal blank in reduction of its thickness, substantially obstructing the free fiow of the metal during said forging operation towards the near end of said blank but not towards the far, end, and applying'rolling and shaping operations lengthwise of said blank thereby developing the longitudinal fiow line to conform to a predetermined die cavity.

10. The method of fabricating propeller blades and the like from a short taper ended metal blank, which comprises applying the required forging pressure near one end of the blank in reduction of its thickness, and applying rolling and shaping operations lengthwise of said blank without releasing the required forging pressure thereby developing the longitudinal fiow line to conform to a predetermined die cavity.

11. The method of fabricating propeller blades and the like, which comprises subjecting a short metal blank with one end tapered to a forging operation in reduction of its thickness, and to simultaneous rolling and shaping operations lengthwise of the blank starting from said reduced in thickness part and rolling towards said tapered end.

12. The method of fabricating a propeller blade and the like, which comprises sawing or otherwise cutting at an angle a rolled metal blank, subjecting said blank adjacent to the opposite end to a forging operation in reduction of its thickness, and starting from said reduced in thickness zone simultaneously rolling, shaping and twisting the blade to the required thickness.

13. A method of fabricating propeller blades or the like, which consists in placing a metal blank shorter than the finished blade between two dies formed with die cavities corresponding to the shape of the finished blade, at least one of the dies being a roller, forcing the two dies together with sufficient pressure to produce a forging effect on one part of the blank, thereby forming aportion of the blade adjacent its hub end, and then causing the roller die to press the blank against the other die while moving the blank relative to the roller without releasing the forging pressure, thereby rollingxand drawing the metal toward the tip of the propeller blade, producing a favorable grain structure to conform to a pre determineddie cavity.

14. A method of fabricating propeller blades or the like, which comprises placing a metal blank shorter than the finished blade between two dies formed with die cavities corresponding to the shape of the finished blade, at least one of the dies being a roller, forcing the two dies together with sufficient pressure to produce a forging effect on onepart of the blank, thereby forming a portion of the propeller blade adjacent its hub end, causing the roller die to press the blank against the other die while moving the blank relative to the roller without releasing the forging pressure, thereby rolling and drawing the metal toward the tip of the propeller blade, producing a favorable grain structure and forcing the metal into the die cavities, and passing the blank through the dies a plurality of times, the distance between the dies being reduced on a subsequent pass. v

15. A method of fabricating propeller blades or the like, which comprises severing a cylindrical piece of metal along a diagonal line, thereby producing a blank shorter than the finished blade and having a square-cut end and a tapered end, placing the blank between two dies formed with die cavities corresponding to the shape of the finished blade, at least one of the dies being a roller, securely gripping the square-cut end of the blank, forcing the two dies together with sufiicient pressure to form a portion of the hub end of the propeller blade, and then causing the roller die to roll over, the blank toward the tapered end of I the blank without releasing the forging pressure,

tip of the propeller blade, producing a favorable grain structure and forcing the metal into the die cavities.

16. A method of fabricating propeller blades or the like, which comprises placing a metal blank between a flat die and a roller die, anchoring one end of the blank at one end of the flat die, forcing the roller die against the blank adjacent the anchored end of the blank with suflicient pressure to produce a-forging effect, thereby forming a.

portion of the propeller blade adjacent its hub end, subsequently causing the roller to move over the-blank and the fiat die without releasing the forging pressure, and simultaneously tilting the flat die relative to the roller die, thereby rolling and drawing the metal toward the tip of the propeller blade, producing a favorable grain structure and shaping the propeller blade.

17. A method of fabricating'propeller blades or the like, which comprises placing a metal blank between two roller dies, gripping one end of the blank, forcing the roller dies together against the blank adjacent the gripped end. of the blank with sufiicientpressure to produce a forging effect,

thereby forming a portion of the propeller blade adjacent its hub end, and subsequently passing the blank through the roller dies without releasing the forging pressure, thereby rolling and .drawing the metal toward the tip of the prothe roller dies without releasing the forging pressure, thereby rolling and drawing the metal toward the tip of the propeller blade, producinga favorable grain structure and shaping the propeller blade. I

19. A method of fabricating propeller blades or the like, which comprises placing a metalblank shorter than the finished blade between two dies formed with die cavities corresponding to the shape of the finished blade, at least one of the dies being a roller, the blank being contacted at the hub end y an abutment which obstructs flow of the me al, gripping the blank adjacent the hub end, causing the roller die to contact with the blank at a point adjacent the hub end with sufficient pressure to produce a forging effect and to force the metal into the die cavities, and then causing the roller die to roll to the blade tip at the required pressure, thereby diepressing the metal at the hub end and rolling the blade from the hub to the tip'by one continuous, uninterrupted process.

20. A method of fabricating propeller blades or the like, which comprises placing a metal blank shorter than the finished blade between two dies formed with die cavities corresponding to the shape of the finished blade, at least one of the dies being a roller, the hub end of the blank being placed against a stop, which serves to locate the blank relative to the dies andto obstruct flow of metal, gripping the blank adjacent the hub end, causing the roller die to contact with the blank at a point adjacent the hub end with sufficient pressure to produce a forging effect and to force the metal into the die cavities, and then causing the roller die to roll to the blade tip at the required pressure, thereby die-pressing the metal at the hub end and rolling the blade from the hub to the tip by one continuous, uninterrupted process.

JOHN W. SMITH.

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