US3147539A - Method and apparatus for producing blades - Google Patents

Description

p 8, 1964 w. A. PAILLE ETAL 3,147,539

METHOD AND APPARATUS FOR PRODUCING BLADES Filed Oct. 9, 1958 ll Sheets-Sheet 1 .srmemv INVENTOR5. 14715500 4. P4/[ Z A q #1 E BY 65 5 4/ L Iii 4.04

P 8, 1964 w. A. PAILLE ETAL 3,147,539

METHOD AND APPARATUS FOR PRODUCING BLADES Filed Oct. 9. 1958 11 Sheets-Sheet 3 INVENTOR5. Mazda/z m/zzf FER/$46M Fan 15a BY 65% 55 1/ L e 6J4 Sept. 8, 1964 w. A. PAILLE IETAL 3,147,539

METHOD AND APPARATUS FOR PRODUCING BLADES Filed 00;. 9, 1958 ll Sheets-Sheet 4 f/V 561/ L zwzo Sept. 8, 1964 w. A. PAILLE ETAL METHOD AND APPARATUS FOR PRODUCING BLADES Filed Oct. 9, 1958 ll Sheets-Sheet 5 Sept. 8, 1964 w. A. PAlLLE ETAL 3,147,539

METHOD AND APPARATUS FOR PRODUCING BLADES Filed 001;. 9. 1958 ll Sheets-Sheet 6 mvmons #015200 7. P/J/ME 669/166 M Fan/415E BY f/VE 5 1 L g w. A. PAILLE ETAL 3,147,539

11 Sheets-Sheet 7 Sept. 8, 1964 METHOD AND APPARATUS FOR PRODUCING BLADES Filed Oct. 9, 1958 mm K p 1964 w. A. PAILLE ETAL METHODANDAPPARATUS FOR PRODUCING BLADES Filed Oct. 9. 1958 11 Sheets-Sheet 8 P 8, 1964 w. A. PAILLE ETAL 3,147,539

METHOD AND APPARATUS FOR PRODUCING BLADES Filed Oct. 9, 1958 ll Sheets-Sheet 9 I L z u I /;J INVENTOR5.

7 Fen/w M. Far/we iHPE If??? nrmem-y- Se t. 8, 1964 w. A. PAILLE ETAL. 3,147,539

7 METHOD AND APPARATUS F OR PRODUCING BLADES Filed Oct. e, 1958 11 Sheets-Sheet 10 TLEIZ'] ut? ,3 I24 "/20 v 422p A225 J3 I l i I /Zd) II III/II I I III/I I 1111/ I I IIIIIIIIIII United States Patent 3,147,539 METHOD AND APPARATUS FOR PRODUCING BLADES Wilbrod Alfred Paille, Luellow, Vt., and Gene Belli, Arlington, and Frank Maxwell Fowler, Beverly, Mass, assignors to General Electric Company, a corporation of New York Filed Oct. 9, 1958, Ser. No. 766,346 28 Claims. (Cl. 29156.8)

This invention relates to methods and apparatus for the manufacture of blades of the type used in elastic fluid flow apparatus and the like.

With the advances made in the design criteria of elastic fluid flow apparatus, such as turbine engines, the required precision in the dimensioning of the blades has made necessary machining, grinding, polishing, and tumble-finishing operations which are costly and time-consuming. Moreover, manufacturing operations heretofore used do not assure the elimination of subsurface imperfections including folds, laps, and cold-shuts.

It has heretofore been proposed to roll-form the blades from work pieces including enlarged heads and by means of which the airfoil section is reduced to approximately its final dimensions.

It is an object of the present invention to provide a method and apparatus by means of which the aerodynamic surfaces of the blades of simple and complex shapes may be made in the absence of imperfections of any character resulting from any part of the blade-forming operations and by means of which the blades are completely and accurately finished with minimum require. ments in respect to final finishing operations.

In carrying out our invention in one form thereof, a blade blank having a transition region joining a base portion and an airfoil section has a cross-sectional area which gradually increases from the cross-sectional area of the airfoil section to that of the base portion. Such a blade blank is first reshaped into a blade preform by applying to the back surface of the base portion a force of large magnitude which, through pivoted reaction members, develops reaction forces of progressively increasing magnitude angularly directed toward the transition re-. gions to reshape those regions into the top surface of the base portion and to form smoothly curved fillets from said transition regions. In forming the fillets, that part of the airfoil section adjacent them has its cross-sectional area reduced so that there may be received therewithin relatively movable arcuate surfaces of dies which further reshape the fillets and which are also mounted for roll-forming the airfoil section. During the reshaping of the fillets, a substantial force is applied to the back surface of the base portion to press the base toward the die surfaces adjacent the curved corner portions thereof.

During the roll-forming of the airfoil section, the force theretofore urging the base portion toward the roll-forming dies is reversed to maintain the blade in tension during the roll-forming of the airfoil section thereof.

Following the roll-forming, the blade preform is placed between a pair of coining dies having metal-shaping surfaces for engaging the airfoil section, and additional surfaces for engaging the top surface of the base portion. Concurrently with the coining operations, a force of substantial magnitude is again applied to the bottom face of the base portion to urge the top surface thereof against opposite surfaces of the coining dies.

The methods and apparatus characterizing the present invention provide great flexibility in the manufacturing operations, thus to make possible the accommodation of limitations in the starting materials to be used for the blades. For example, some metals, such as alloys of the nickel base type, must be annealed after each extruding,

3,147,539 Patented Sept. 8, 1964 'ice rolling, or upsetting operation before further reshaping may be satisfactorily accomplished. In other instances, whether the annealing be necessary or unnecessary, there will be enhancement of product quality by repeating selected method steps gradually to shape the metal into final form. In accordance with the present invention, there are provided provisions by means of which there is attained precise positioning of the parts for each successive pass, that is, for each repetition of selected steps to be carried out and as will be more fully described hereinafter.

We have found that in the practice of our methods and by the use of our apparatus, the aerodynamic surfaces including the' airfoil section and the top surface of the base portion, except for a slight shaping or rounding of the narrow edge portions, may be brought to their final finished form without the need for further treatment of said surfaces. In addition to the production of blades of higher and uniform quality, the present invention has resulted in large and substantial savings in the manufacture of blades for use in elastic fluid flow apparatus.

In referring to the manufacture of blades, we use that term in the generic sense to include buckets, vanes, struts, and equivalent structures which are known in different arts under different names.

The subject matter which We regard as our invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. tion, however, both as to organization and method of operation, together with further objects and advantages thereof, may best be understood by reference to our description taken in connection with the accompanying drawings in which:

FIG. 1 is a perspective view of a starting slug;

FIG. 2 is a partial sectional view of the extruded blade blank after extrusion in and prior to removal from an extruding die;

FIG. 3 is a perspective view of the extruded blade blank;

FIG. 4 is a fragmentary sectional View of the extruded blade blank in our prepinching apparatus prior to the prepinching operations which produce a blade preform;

FIG. 5 is an enlarged fractional sectional view of the parts of FIG. 4 after the formation of the fillets and prior to upsetting of the base;

FIG. 6 is a fragmentary sectional view of the parts of FIG. 4 in their final positions which produce the blade preform;

FIG. 7 is a diagrammatic illustration of one embodiment of our prepinching apparatus for forming blade preforms;

FIG. 8 is a force diagram explanatory of the operations performed by the apparatus of FIG. 7;

FIG. 9 is a perspective view of the prepinched blade blank which is also referred to as the blade preform;

FIGS. 10-13 are fragmentary sectional views of the method of introduction of the blade preform into the roll-forming apparatus;

FIG. 14 is a fragmentary sectional view of the parts of FIG. 10 and of the blade preform after further shaping operations;

FIG. 15 is a fragmentary sectional View of the blade in our roll-forming apparatus in a momentary dwell position just prior to rolling;

FIG. 16 is a fragmentary sectional view of the blade in our roll-forming apparatus just after the initiation of rolling;

FIG. 17 is a fragmentary sectional view of the completion of our roll-forming operations;

FIG. 18 is a perspective view of the blade after rollforming;

Our inven-v FIG. 19 is a diagrammatic side view of one embodiment of our metal-shaping and roll-forming apparatus in the fully opened position;

FIG. 20 is a sectional view taken along the line 2fi-20 of FIG. 19;

FIG. 21 schematically illustrates, with some exaggeration, the manner in which the movable die of FIGS. 10 13 moves into and out of registry with a blade preform;

FIGS. 22 and 24 are like FIG. 19 but with the parts in different positions;

FIG. 23 is an enlarged fragmentary sectional view of the roll-forming dies in the virtually closed position;

FIGS. 25-28 are fragmentary sectional views of the coining apparatus for the rolled blade preform illustrating different positions during coining FIG. 29 is a perspective view of a coined-upset blade; and

FIG. 30 is a perspective view of a trimmed blade.

The present invention is particularly concerned with the operations to be carried out upon a roughly shaped blade blank 10, such as illustrated in FIG. 3. Though the blade blank 10 may be produced in different ways, we prefer to produce the blank by extruding it from a starting slug illustrated in FIG. 1. A ram 11, FIG. 2, squeezes, or more particularly extrudes, the material through a shaping die 12, it being understood that the starting slug will have been heated to the requisite temperature to facilitate the extruding operation. After the extruding operation, the blade blank will be cleaned preparatory to the next sequence of operations. The blade blank 10, the blade preform 13, of FIG. 9, the rolled blade 53 f FIG. 18, and the coined and trimmed blades of FIGS. 29 and 30 are respectively characterized by the presence of a base 101: having a bottom surface 10e and a top surface 10s and also having an extension 10a forming the airfoil section. A transition region 1013, to be shaped into fillets 101, FIG. 5, has a cross-sectional area which gradually increases from that of the adjoining portion of the airfoil section until it merges with the top surface 10s of the base 10b.

In order to reduce to a minimum the possibility of surface imperfections due to the metal-shaping operations needed to convert the blade blank 10 into the substantially finished blade of FIG. 29, the blade blank will first be converted into the blade preform 13 illustrated in FIG. 9 and in more detail in the cross-sectional view of FIG. 6. To produce the blade preform 13, the blade blank 10 is, FIG. 4, disposed between opposed protuberances 14a and 15a of a pair of dies 14 and 15, the protuberances engaging the top surface 10s adjacent transition region ltlt. The dies 14 and15 carrying the protuberances 14a and 15a are in turn supported on reaction members, later to be described in more detail, and so arranged that upon application by a ram 16 of a force 17 of substantial magnitude to the bottom surface like of the blade blank 10, there will be developed, through movement of die members along arcuate paths 1-8 and 19, angularly directed forces and 21, FIG. 5, applied to the top surface 10:. at the transition regions 101 to reshape that surface and those regions to include smoothly curved fillets 10f which lie between top surface 10s and a region of substantially reduced cross-sectional area of the airfoil extension 10a.

In reshaping the transition regions ltlt, the protuberances 14a and 15a act upon the top surface 10s and transition regions 102 in a manner which may be visualized, FIG. 4, asmovement of the protuberances 14a and 15a angularly toward and into the transition regions 10t. With this visualization of the action and with the base 1% for the moment assumed to be in fixed position, it will be seen that as the protuberances 14a and 15a reshape the top surface 19s, metal is displaced by the protubcrances. Some of the displaced metal moves along the top surface 10s toward the airfoil section 19a. Some of it moves outwardly. At the same time, the airfoil section 19a is lengthened by the reduction in its crosssectional area in the region ltlr adjacent the fillets 10f. Thus, in the final positions of the protuberances 14a and 15a, FIG. 5, it will be seen that the smoothly curved fillets 10f interconnect the base portion 10b and that portion 10r of the airfoil section 10a of reduced cross-sectional area. By reason of the smooth, divided flow of a minimum of metal, there are avoided folds, laps, and surface-closed subsurface cavities known to those skilled in the art as cold-shuts. In FIG. 5, the dies 14 and 15 are in their final positions, but the metal-shaping operations have not been completed. It will be noted that there remain slight clearances or unfilled regions or spaces 23 located at the respective edges of the top surface of the blade blank. These spaces 23 are filled by upsetting the base 1% in the following manner. As the dies 14 and 15 are brought to standstill in the positions shown in FIG. 5, the forces 20 and 21 change from kinetic to potential forces, that is, they become holding forces. The force 17 is then effective, FIG. 6, to cause flow of metal into the spaces 23. This metal flow results from an upsetting action which, though not needed, may sometimes also produce a slight outward flow of metal at the back surface 10@ into the area 16a, and as best illustrated by the flash 10m in FIGS. 6 and 9.

To set forth the important features of the invention thus far described has required step-by-step treatment. In practice, and as will now be explained, the foregoing operations are smoothly, continuously and rapidly carried out upon actuation of a press which moves the plunger or ram 16 from an initial position to a final position after which it returns to its initial position.

In a preferred form of the invention, FIG. 7, the dies 14 and 15 with their curved protuberances 14a and 15a are carried by two reaction levers or members 25 and 26 respectively pivoted at their remote ends by pivot pins 27 and 28 to a supporting structure or frame 30, preferably of steel. The levers or reaction members 25 and 26 produce in conjunction with the blade blank 10 a toggle action which upon application of a substantial force to the back surface 10e develops reaction forces R, FIG. 8, applied toward the transition regions 101 of the blade blank 10. These forces R rapidly increase upon displacement of the reaction levers 25 and 26 from their initial positions toward their final positions.

In their initial positions the levers 25 and 26 lie at angles a measured from a line 31 interconnecting the axes of their pivotal mounting means 27 and 28. This angle or is preferably relatively small with the reaction levers 25 and 26 in their initial positions and decreases to about ten degrees or less with rotation of the levers about their pivot points in directions to reduce the separation distance between the protuberances 14a and 15a, thereby to produce the smoothly curved fillets 101, FIG. 5, and to reduce the adjacent cross-sectional area 10r of the airfoil section. More particularly, if the entire actuating force P, FIG. 8, be applied to the back surface 10e by the mechanically or hydraulically actuated thrust member 16, there will arise oppositely acting reaction forces 1. Mathematically, P=2p. However, the reaction forces R will be of greater magnitude than the applied force P and many times the magnitude of each opposing force p. Mathematically,

2 sin a This expression means that as the angle a approaches zero, the sine of a approaches zero. Accordingly, the reaction forces R rapidly increase, with value infinity as their limit. Stated differently, the reaction forces R increase inversely as the cosine of the angle A between the side p of the force diagram of FIG. 8 and the hypothenuse R thereof. The maximum magnitude of forces R tend to be limited by elongation of the base plate 30, of steel. The elongation of the heavy supporting plate is small but play its part in controlling the magnitudes of the forces applied to blade blank 10.

With the foregoing understanding of the force diagram and the manner in which the reaction forces R are directed angularly toward the transition sections, it will be understood that the metal-shaping forces may comprise forces applied directly to the levers 25 and 26 concurrently with the application to the back surface a of a force to hold the blade blank into the position illustrated in FIG. 7 and to maintain it between the protuberances 14a and a until the final positions of the die members have been attained, as illustrated in FIGS. 5 and 6.

As shown in FIGS. 4-7, the force-applying means 16 is provided with a recess 16a within which the base portion of the blank 10 may nest, with clearance with the walls of the recess. The depth of the recess is selected to control, in conjunction with the recess 32 in FIGS. 4 and 7 jointly provided by the die structures, the thickness of the base of the blade preform when the force-applying means 16 is brought to its final position as shown in FIG. 6. The peripheral end surface 16b, FIG. 5, then engages the top surfaces 14b and 15b of the die members which form stops for ram 16. Thus, there is predetermined in accordance with the combined depth of the two recesses 16a and 32 the desired thickness needed to control the base of the blade preform of FIG. 9. The recess 32 provided by the dies 14 and 15 has walls which also predetermine the dimensions of nearly all of the side wall portions of the base 10b, since in the upsetting operation carried out in the apparatus the metal of the base portion is upset until there is intimate contact with the walls of that recess. However, the recess 16a provided in the force-applying member 16 is of greater cross-sectional area than recess 32 to provide clearance circumferentially about the bottom face 10a, thereby to provide the earlier mentioned metal-flowing space to accommodate flash 10m. Such a metal flow occurs during the upsetting operation in varying degree dependent upon the mass of metal initially comprising each base portion and resulting from the above-described extruding process. Though the mass of each base portion will be relatively uniform, there will be some variation which will result in flashes or metal flows 10m, FIG. 9, of differing degree. As shown in FIG. 6, there will in most cases be some free space about the final flash that may be formed. In the final position of the dies, as shown in FIG. 6, the base of the blade blank will have been reshaped so that its respective surfaces will intimately contact and conform with all surfaces of the walls forming the recess 32.

It will be further observed, FIG. 7, that as the reaction levers and 26 are moved downwardly with decrease in the angle a, the lower portions thereof come to rest against fixed stops 33 and 34. As soon as these stops are engaged by the reaction levers, the reaction forces R become holding forces. The continued application of the force P as by the member 16 produces the final upsetting operation which has just been described. At this point the force P may be reduced to zero, hydraulically by operation of control valves, or mechanically by the passage of the stroke-applying means past the dead-center position. Thereupon, springs 35 and 36 are effective to rotate the levers 25 and 26 to return them to their initial positions. At the same time, there is effective a piston or spring means 37 to actuate upwardly an ejector 38, extending through an opening in the base plate 30, into engagement with the air-foil section 10a to move the blade blank outwardly of the levers. The upward move ments of members 25 and 26 are limited by adjustable stops 39 and 40 carried by members 25 and 26.

The angular movement of dies 14 and 15 with the protuberances 14a and 15a in predetermined initial positions, as shown in FIGS. 4 and 7, assures accurate positioning of each blade blank. This feature is of importance when the characteristics of a particularly alloy require a succession of the processing operations to bring the initial blade blank 10 to the desired dimensions for the blade preform 13 of FIG. 9.

Since the positioning of each part relative to the die members is certain and automatic, the metal-shaping operations always take place along the top surface 10s and and including the transition regions 10t adjacent the airfoil section 10a.

1 With the blade preform 13 brought to its desired dimensions, which in general will include the diminution at 102' of the cross-sectional area of the airfoil section adjacent the fillets 10 to slightly larger than the final cross-sectional area of the finished airfoil section, the second stage in fabrication of the finished blade can begin after there has been removed from the preform any flash, such as shown at 10m.

In some cases it will be desirable to clean and anneal the blade preform 13 before initiating the roll-forming operations now to be described. The cleaning operations will be essential for those cases in which the preforming or prepinching operations are carried out on blade blanks the surfaces of which have been contaminated such as by oxidation.

As illustrated in FIG. 10, the blade preform 13 of FIG. 9 is securely held by holding means 42 which though biased upwardly, moves in the direction of arrow 43 to place the blade preform between the pair of die members 44 and 45 relatively movable one with respect to the other to decrease the separation distance between curved metal-shaping corners respectively interconnecting shoulder portions 44a and 45a and curved sections 440 and 45c. As shown, the die member 44 is moved downwardly. Its engagement with the airfoil section 1011 tilts the airfoil section downwardly at the same time the holding means 42 is moving the preform 13 inwardly toward the shoulders 44a and 45a. In the final position of the parts as illustrated in FIG. 14, the top surface 10s of the preform 13 is pressed against the shoulder portions 44a and 45a by a force indicated by the arrow 46 and the blade preform is no longer biased upwardly.

The holding means 42, as later illustrated, is mounted for rotary movement upon engagement of the upper surface of the airfoil section 10a, as shown in FIG. 10, by the die 44, the holding means 42 as a whole being biased to maintain the airfoil section 10a against the die 44, but without substantial opposition to said rotary move! ment. The positioning of the blade preform between the dies is certain and adapted to the positioning of blade preforms for a succession of operations of the type to be described in avoidance of any possibility of consequential galling and undesired disturbance of the airfoil surfaces, particularly the top surface 10s.

Referring now to FIGS. 11-13, the die 44 is moved toward the blade preform 13 and toward die 45 along an arcuate path, later to be described in more detail in connection with FIG. 21. Such a path is indicated generallyby the successive positions of die 44 and arrows 41 which show the change in direction of movement.

As shown in FIG. 11, as die 44 pivots blade preform 13 toward die 45, the spaces or gaps 47, 47a, 48 and 48a are decreased, gap 47 being greater than gap 48 because of the upward bias of the blade preform. These spaces or gaps are shown somewhat exaggerated for clarity or illustration. The blade preform, therefore, is moved downward as well as toward the dies generally in the direction of arrow 43. i

' Die 44 continues to move blade preform 13 toward die 45 until contact of the preform with die 45 is made, FIG. 12. Blade preform 13 is still biased upwardly allowing the nose portion of die 44 between surfaces 44a and 44c to fit accurately and snugly into the fillet of the preform. As the above described nose of die 44 closes into the fillet, force is applied the resultant of which is shown by arrows 49 and 49a to shape and form the fillet area. The blade preform 13 now is no longer biased upwardly. As shown in FIG. 13, gaps 47, 48, 47a and 48a still exist but now are nearly symmetrical about center line 110.

Preferably, the forward movement of the holding means 42 is arrested as the parts approach the position shown in FIG. 12. As the die 44 arrives in about the position of FIG. 13, the arresting means is freed by the movement of die 44. The holding means 42 is then moved positively and synchronously with die 44 until the parts attain their final positions as shown in FIG. 14. The top surface 19s is then seated against the shoulders 44a and 45a. There is concurrently applied a substantial force 46, FIG. 14. There will be achieved any needed further reshaping of the top surface 10s and of the fillets to conform with the surfaces of the dies 44 and 45.

The holding means, as best shown in FIGS. 11-13, has opposite horizontal surfaces 42a and 4212 which cooperate with guiding surfaces 445 and 45b to establish a fixed and reproducible vertical relationship between the base portion 10b and the airfoil section 10a. With this relationship established, FIG. 13, the force 49 moving the die member 44 into its final position will develop a reaction force 49a. These forces are both angularly directed toward the fillets. If the fillets be of shape other than in exact conformity with the curved nose portions of each die, they will be reshaped into exact conformity therewith.

As will be shown later, FIG. 20, this vertical relationship is complemented by a controlled horizontal relationship to assure exact and reproducible location of the blade preform 13 relative to the dies 44 and 45 if consecutive roll forming operations are to be performed.

With the final positioning of the blade preform between dies 44 and 45, and upon completion of the fillet and top surface sizing operation, the dies are maintained in fixed space relationship one to the other for a short dwell time, FIG. 15. At that time kinetic forces 46, 49 and 49a of FIG. 14 become potential forces 46a, 49b and 490, FIG. 15, to hold the preform and allow the metal sized to complete its flow or movement. The dwell time may be accomplished by a series of controls, later to be described in connection with FIGS. 19, 22 and 24.

The dies 44 and 45 are then relatively rotated, arrows 50, FIG. 16, to roll-form the airfoil section 10a. The roll-forming is accomplished with the blade preform 13 maintained under tension, as shown by arrow 51, a tension of magnitude adequate to prevent the preform from following the curved portions 44c and 450 of either of the dies and of a magnitude which is maintained substantially constant, notwithstanding changes in the surface speeds of the curved die surfaces 440 and 450. The rolling forces are generally indicated by arrows 52. In FIG. 16 the blade preform has been shown in a position slightly displaced to the right by the curved surfaces 44c and 45c from the position illustrated in FIGS. 14 and 15. The rolling action continues, as shown in FIG. 17, to reduce the cross-sectional area of the airfoilv section and to shape it into conformity with the die surfaces 440 and 450. As the tip of the airfoil section leaves the curved die surfaces, a bias on the holding means 42 tilts the rolled blade preform 53 upwardly and away from the die structure and to the broken-line position for easy removal upon release by the holding means 42. The rolled blade preform 53, FIG. 18, has smooth airfoil surfaces 10a and has a controlled thickness throughout the intended length thereof. Thus the blade preform 53 has a length and width materially greater than that required in its final form. The irregularities illustrated at the tip end can occur as the result of repeated rolling operations and by relief (increased spacing between the curved surfaces 440 and 450) after the useful portion of the airfoil section has been accurately brought to the desired roll-formed dimensions.

Referring now to FIGS. 19-23, there has been illustrated a preferred apparatus for reshaping the top surface of the blade preform 13 and to roll-form the airfoil section in manner already described. Thus, FIG. 19, the die 45 is carried by a roll 55 carried by a shaft 56 pivoted between upturned portions 57a of frame 57. Thus the roll and the die 45 are held in fixed position relative toframe or foundation 57. The die 45 may be rotated upon movement toward the left of a link 63 pivotally connected through a pivot pin 62 to the ends of a pair of levers 61 which have their opposite ends secured to roll 55. The link 63 has its opposite end connected by pivot pin 64 to an equalizing link 65. Equalizing link 65 is secured to the piston or ram 67 of a hydraulic operator 68 by a pivot pin 66 located at a point midway on equalizing link 65 and slightly to the left of a line through the center of pivot pins 64 and 77.

The bodily movable and rotatable die 44 is carried by a roll 78 supported by a shaft 71 guided by arms 72a and 72b of a supporting structure pivoted by shaft 73 to frame 57. Levers 74 secured at corresponding ends to roll extend upwardly from roll 70 and by pin 75 are pivoted to one end of a link 76, the opposite end thereof being connected to equalizing link 65 by pivot pin 7 7 Pivotally connected to pin or stub shaft 71 is a ram member 78, mechanically or hydraulically driven for bodily moving die 44 toward and away from die 45. It will be recalled that the dies 44 and 45, FIG. 10, have faces 44a and 45a which terminate in the curved edge or nose portions which merge with arcuate rolling surfaces 44c and 450. Since the dies 44 and 45 rotate respectively about the axes of shafts 56 and 71, it is important during the movement, bodily, of the die 44 toward die 45 that the piston 69 of operator 68 for rotating the dies shall exert sufficient force to maintain continuous contact between link rods 63 and 76 and their respective stops 83 and 84. This may be accomplished by any suitable means, such for example, as a hydraulic actuating system which normally from a sump tank 80 and a constant volume pump 81 applies through a pressure line 82, a one way valve 82a and a solenoid valve 87a a hydraulic pressure to the left hand side of piston 69. In this arrangement, piston 69 maintains a forward velocity depending on the rise or fall of ram 78 and hence arms 72a and 72b. This maintains links 63 and 76 in the positions illustrated in FIG. 19. The lower end of link 63 abuts against an adjustable stop 83 carried by frame 57. The right-hand end of link 76 abuts against an adjustable stop 84 carried by a crossmember interconnecting arms 72a and 7212. Thus, the die 45 will not rotate as die 44 is moved. toward it, and equalizing link 65 rotates to equalize links 63 and 76.

There is included in the pressure line 82 a pressure relief valve 85 having an adjusting means to predetermine the magnitude of the hydraulic pressure which may be applied to an operator 86 as well as to maintain a minimum pressure in line 82 and hence in operator 68. That is, the pressure relief valve 85 assures a differential pressure as between operators or actuators 68 and 86 so that the pressure on actuator 68 is always materially in excess of that applied to the actuator 86.

Assuming now that the solenoid valve 78a is in the position illustrated in FIG. 19, the fluid from pump 81 first forces piston 69 to the right to cause contact of links 63 and 76 with their respective stops 83' and 84 as shown. Then, when pressure in line 82 exceeds the adjusted minimum of relief valve 85, line 82 becomes pressurized. When solenoid valve 87b is actuated into the posithun shown in FIG. 9, fluid will act on piston 88 to move it to the left. In so moving, it displaces air into a pressure or air tank 89. This compressed air is utilized to place the preform 13 under tension during roll forming and also to return shuttle 90 to the position illustrated in FIG. 19.

It will be further assumed that a preform 13 has been inserted in the holding means. The blade preform may be readily placed in the holding means 42 since the shuttle 90 carrying it is held in an upwardly inclined position by a roller 91 engaging an extension 92 of the shuttle 90. It is convenient, though not essential to the invention, to elevate the holding means as illustrated in FIG. 19 for ease in placing the blade preform within the holding means which is then operated to hold securely the preform by an actuating means 93. The details of the holding 9 and actuating mechanisms are conventional and, therefore, have not been illustrated in detail.

With the blade 13 held, and hydraulic fluid admitted to the actuator 86, the shuttle starting switch is activated and the piston rod 94 moves the shuttle 90 along guideways 95 of a carriage 96 to move the blade preform 13 toward the dies 44 and 45. Shuttle 90 will be moved to the left until a stop 90a and a switching means 90b on shuttle 90 contacts a stop 99c on carriage 95 to actuate ram 78. The carriage 96 is also slidable, supported in guideways 97 of the main frame 57.

As the shuttle 90 moves away from roller 91, it rotates by gravity or may be positively moved by a spring, not shown, about the pivot pin 98 which is roller-mounted in guideways 95 of carriage 96. As the shuttle descends, its lower surface engages an upwardly biased plunger 99. It is this plunger that positions the preform 13 in the angular position shown in FIG. for entry between the dies 44 and 45.

As the blade preform 13 is moved beneath the upper die 44, switching means 90b initiates a downward movement of that die member through the mechanically or hydraulically actuated ram means 7 8 which are pivotally connected to shaft 71. This downward movement, incident to the use of a mechanical press actuator, will be quite rapid. Accordingly, to assure accurate and precise registration of the preform 13 between the dies prior to engagement with any part of the preform, there is provided synchronizing means comprising actuating levers 101 pivoted at 102, which normally through the action of a spring 103 maintain carriage 96 in its right-hand position. The levers 101 can move the carriage 96 to the left or toward the dies by a predetermined amount. Thus when adjustable actuating surfaces 104 carried by the arms 72a and 72b engage the upper surfaces of the levers 101, there is a rapid movement of the carriage 96 to the left, against the bias of spring 103 to produce the force represented by arrow 46 of FIG. 14 and to seat the top surface 10s of the blade preform 13, FIG. 14, against the surfaces 44a and 45a at the same time that the curved nose portions of the die members 44 and 45 are moved inwardly into and against the fillets of the blade preform 13 as has been previously described. Inasmuch as the move ment of carriage 96 is produced entirely by the engagement of levers 101 by the surfaces 104, there is synchronized and precise movement of the preform 13 into and between the dies 44 and 45 as shown. In this connection, it is to be noted that the top surface 10s throughout a major portion of its area engages surfaces 44a and 45a for precise positioning. That top surface 10s is maintained against surfaces 44a and 45a with a force equal to that developed by the actuator 86. Actuator 86 will counteract any over-travel of the carriage 96 beyond the point where the top surface 19s and the surfaces 44a and 45a are in engagement, as shown in FIGS. 14 and 15. Such over-travel of the carriage 96 cannot be transmitted to the shuttle 90, since there is a corresponding right-hand movement of the piston rod 94 of the actuator 86 relative to carriage 96, thus to permit the shuttle 90 carried thereby to remain stationary relative to surfaces 44a and 45a. The levers 101 are provided with adjustable stops 105 mounted in frame 57 to adjust the travel of carriage 95 produced by biasing means 103.

Since the upper die 44, FIGS. 10-13, has surface 44a disposed in sharp angular position relative to the curved surface 440, it is important that there be minimized any possibility of engagement of the curved edge or nose portion of the die 44 with the upper corner of the blade preform 13 as the dies are moved inwardly. Accordingly, the die 44 is arranged to swing about an are 107, FIG. 21, which generally can be described as being tilted away from the final position of surface 19s. More precisely, and as best Shown in FIG. 21, a tangent 1118 from the arc of movement of die 44, taken from the point 109 of intersection thereof with the center line 110 formed by a trace of the central airfoil-rolling plane between the die members 44 and 45, lies at an angle A to a line perpendicular to the line 110. This angle A is produced by locating the axis of shaft or pivot pin 73 for the supporting arms 72a and 72b at a point nearer the die 45 than the die 44 and particularly in a direction displaced toward die 45 from the line 119 as indicated by the somewhat exaggerated displacement dimension X in FIG. 21.

FIG. 21 alone does not delineate in full the positioning of die 44 as it traverses its arcuate travel path 107. Thus in FIG. 21, the arc is shown as passing through the curved nose portion of die 44.

As best shown in FIGS. 19 and 20, it will be noted that the dies 44 and 45 are carried by the rolls 70 and 55 midway thereof and with the arcuate surfaces, FIG. 23, 10-,

cated so as to leave a very slight spacing as indicated at 114, 115 on either side of the die cavity 112. With the dies in the positions of FIGS. 22 and 24, the rim portions 55a and 70a of the rolls 55 and 70 engage each Othwd thus absorb the downward force applied by the actuating means 78. The rollingpressure on the airfoil section of the die is thus applied indirectly rather than directly from the actuating means 78. Thus, the rim portions of the rolls 55 and 70 may be loaded to a greater extent than is actually required by the dies 44 and 45. The effect of the increased loading is to insure that the dies will perform their rolling functions, since the rolling forces will be maintained notwithstanding any slight deflection that may occur in the apparatus. This is a factor contributing to the high quality of the product. As shown in FIG. 20, shock absorbers 116 in the form of rubber cushions may be included on the frame 57 to absorb kinetic energy from ram 78 and connecting parts. Thus damage to the rims 55a and 70a is avoided.

As was mentioned before in connection with FIGS. 11-15, surfaces 42a and 42b on the holding means 42 cooperate with guiding surfaces 44b and 4512 respectively to establish a fixed and reproducible vertical relationship between the base portion 10b and the airfoil 10a. A similar fixed and reproducible horizontal relationship is established through the cooperation of surfaces 7% and 55b, FIG. 20, with vertical side surfaces 420 of holding means 42, FIG. 19. Thus guiding surfaces on the rims and rolls cooperate with guiding surfaces on the holding means to estabish a fiXed and reproducible positioning of the blade preform 13 in both the horizontal and vertical directions. This precise positioning arrangement allows accurate consecutive operation of rolling cycles thereby avoiding scuffing on recycling of the surfaces already formed.

With the dies closed, FIG. 22, and after the reshaping of the fillets by the movement of the force-producing means 78 from its initial to its final position to bring the dies to their final positions, as shown in FIGS. 14 and 15, a solenoid operated valve 87a is actuated by timed switching means 113 being contacted by arm 72a to transfer the hydraulic pressure to the right-hand side of piston 69 for actuation of the piston rod 67 to the left. Through the equalizer link 65, the links 63 and 76 rotate the dies 44 and 45 in directions indicated by arrows 50, FIGS. 16 and 17, to roll-form the airfoil and in a manner above described in considerable detail.

As the valve 87a is actuated to apply the roll-forming .l'orces to the dies, the valve 87b is rotated to connect the oil-filled portion of the actuator 86 to the sump. Accordingly, as soon as valve 87b connects the oil-filled portion of the cylinder to the sump, the compressed air of tank 89 is effective on the piston 88 of actuator 86 to apply a force to move it to the right. This force indicated at 51, FIGS. 16 and 17, places the blade preform 13 under tension during the rolling operations. The parts in positions during the roll-forming are shown in FIG. 24. Upon termination of the rolling operations, the compressed air is effective in returning the shuttle 90 to the illustrated position in FIG. 19 at which point 1 1 it contacts switching means 113a to raise ram 78. The spring 103, FIG. 19 returns carriage 96 to its right-hand position, the heads of cap screws 105 threaded into the frame 57 serving as stops for levers 161 and for the carriage 96.

It is important to note that the intermediate pivotal connection 66 between the equalizer link 65 and piston rod 67 is displaced to the left from a line interconnecting the axes of pivotal connections 64 and 77 of links 63 and 76. By rotation of link 65, FIG. 24, about pivot pin 66 the result of this equalizerof the negative typeis to maintain an optimum balance between the surface speeds of the dies 44 and 45 with a tendency to keep the movement of the dies in proper synchronization. Such action minimizes any slippage or sculfing between the curved die surfaces and the airfoil. Surfaces of improved character are thereby attained on the opposite faces of the rollformed airfoil a of FIG. 18. The absence of slippage as between the dies and the airfoil surfaces also represents a highly favorable factor in extending the life of the dies. The equalizer link 65 is important to each roll-forming operation by reason of the fact that one surface of the airfoil section is convex and the other concave, as best shown by die cavity 112, FIG. 23, thus requiring different rolling curvatures of the dies and, in general, different resistance to roll-forming. It will be noted that the line of action of the piston rod 67 is displaced upwardly from the axis of rotation of the arms 72a and 72b about shaft 73. Accordingly, after completion of the rolling action, a reversal of movement of the piston rod 67 will, through the linkage means, produce a reverse rotation of the two dies to return them to their starting positions, notwithstanding any degree of displacement that may have occurred during the roll-forming operations. This assures accuracy in the return of dies 44 and 45 into the fillet 10 if subsequent roll forming operations are required.

Upon completion of the roll-forming of the airfoil section, the valves 87a and 8715 are returned to the positions shown in FIG. 19.

As the actuator 68 moves rod 67 to the right, the link 65 will be pivoting about its axis 66, while the links 63 and 76 will be rotating the dies 44 and-45. Concurrently, the die 44 will be moving upwardly by reason of the upward movement of the force-applying member 78. Though the spring-biased plunger 99 will already have lifted shuttle 90 to about the position shown by dotted lines in FIG. 17, as the extension 92 engages roller stop 91, the shuttle will be further tilted. to the position of FIG. 19 for easy removal of the finished roll-formed blade upon release of the holding means by the actuator 93.

After the required number of roll-forming operations on each blade preform, the roll-formed blade will be ready for the coining operations which will now be described.

The first step, FIG. 25, in the final coining operation is to place rolled blade preform 53 between a pair of dies 120 and 121 which, as shown in FIG. 25, are initially in spaced relation one to the other. The positioning of the preform 53 between the coining dies is accomplished by holding the base portion 10b in a recess of what may be termed anvil members 122a and 12% adapted to be actuated to press the top surface 10s of the preform 53 against the shoulders 120a and 121a of coining dies 120 and 121 after they have been substantially closed, FIG. 27, and their curved corner portions have seated, or substantially seated, against the curved fillets 10 The anvil or supporting members 122a and 122b are moved to positions where the top surface 10s of blade 53 will engage the surfaces 120a and 121a, a force 123, FIG. 27, being developed of magnitude adequate to assure a sizing, smoothing ironing, or final finishing operation on that top surface. In order that the foregoing operations may be closely controlled, the anvil members 122a and 12211 are moved in synchronism with the closing of the coining dies and 121. This synchronous movement, which takes place as the coining dies close upon the airfoil section, is accomplished, as best shown in FIG. 25, by moving together both the coining die 120 and an actuating member 124 as by actuating means hydraulically or mechanically operated as by a toggle press so that as the coining die 120 moves toward the coining die 121, the actuating member 124 through its inclined surface 124a engages a mating inclined surface 122s of the anvil 122a to move the latter along ways of frame 131 toward the right at a speed preferably greater than the closing movement of the coining dies. The greater speed of the anvil or supporting member 122a will be accomplished if the angle as measured from the horizontal line of movement of member 122a to the inclined surfaces is less than 45.

The top surface 10s and the fillets are reshaped as the coining dies engage the airfoil section 100 but in avoidance of any displacement of metal in any portion of the aerodynamic surfaces of a character which will give rise to any laps, folds, or cold-shuts. The coining operation, which is both a sizing and a final shaping operation of the aerodynamic surfaces, brings into the final desired configuration the airfoil surfaces. As best shown in FIG. 25, the coining surfaces 12Gb and 121k respectively extend upwardly at an angle to the faces 120a and 121a to establish a relationship suitable for certain types of blades. The coining surfaces may extend at any suitable angle which will be determined by the slope of the top surface 10s which is held perpendicular to the movement of die 120.

For the rolled preform 53, the coining surfaces 12012 and 121b are inclined upwardly at an angle such that a line extending through what are termed by those skilled in the art as stacking points in the final coined blade will be at a predetermined angle with reference to surface 10s. In this manner, the coining dies after engagement of the airfoil surfaces impart thereto the warp and other final configurations desired in that section. It will be desirable to actuate the coining dies by a toggle press in order to provide a dwell of the dies in their final positions, that is, a short interval in which the dies are at standstill. The dwell provides time for the metal to flow into its final configuration.

With the parts in position preparatory to the coining operation, FIG. 25, the anvil member 122a is biased, as by spring assemblies 132, to the left and against a stop member 133. As the die 120 and actuating member 124 are moved downwardly, arrow 138, the shoulder or forming face 120a of die 120 has adequate clearance as indicated at 134, FIG. 25, with the top surface 10s of the preform 53 to minimize any possibility of contacting the preform during closure of the coining dies. It will also be observed that the anvil 122i) slidably carried in dovetail ways 122w of anvil 122a is biased upwardly by spring assemblies 135, a shoulder portion engaging a mating shoulder of the anvil member 122a to limit upward movement thereof.

As shown in FIG. 26, the outer tip of the airfoil portion 10a of roll preform 53 is resting on the upper surface of the coining die 121. The movable die 120 has its nose portion engaging the airfoil section adjacent the top surface ltis. The inclined surface 124a of actuating member 124- has almost engaged the mating surface 122s. The engagement of the nose portion of coining die 120 with the airfoil section 10a has displaced downwardly the anvil 122b, as will be evident from a comparison of the positions of the parts in FIGS. 25 and 26. Thus, some bending of the airfoil section 16a has taken place with the parts in the positions shown in FIG. 26. In this connection, it will be understood that the base portion 10b of the preform 53 is securely held in the anvil recess. As the die-closing movement continues, the airfoil section 10a is further bent upwardly relative to the base ltlb.

13 As the die 120 moves from the position of FIG. 26 through the position of FIG. 27 to the position of FIG. 28, the inclined actuating surface 124a of actuating member 124 engages the mating surface 122s of anvil member 122a to produce from force 139 a force 123 and rapidly to move the anvil members 122a and 12212 to right to seat the top surface s against the shoulders or opposing surfaces of the dies 120 and 121 in manner above described. It is to be noted, FIG. 27, that surface 10s is worked prior to complete coining of airfoil 10a. In the final position of the coining dies, FIG. 28, the anvil 12% seats against the frame 131 to limit the downward movement thereof.

Upon completion of the reshaping of the top surface 10s including the fillets 10 and the coining of the airfoil section 10a, the coining dies 120 and 121 are separated and the coined blade, as illustrated in FIG. 29, removed therefrom. The blade is then trimmed to predetermined lengths and width, i.e., which are desired for the particular assembly of blades in a particular assemblage or stage thereof. The length and Width trimming lines, FIG. 29, illustrate, with some exaggeration, the waste metal. The concurrent trimming to width is to meet the requirements of the particular aerodynamic application in providing the thicknesses at the leading and trailing edges needed in the final airfoil section. After the final trimming operation, FIG. 30, it is only necessary to remove trimming burrs and slightly to round the leading and trailing edges of the airfoil section to bring them into c011- formity with the aerodynamic requirements for the application to which the blade is to be applied. The final blade will represent a smoothly curved surface from front to back and including the forward and trailing edges.

Though not essential to the invention, it will be noted that the coining dies 124 and 121 have been respectively provided with a despression 136 and a pointed projection 137 to punch a hole 138 or to place a dimple in, or to pierce, the waste airfoil portion of the coined blade. By providing such a hole or dimple through that waste portion, therecan be accurately established the distance from the base portion to the hole or dimple. Accordingly, with this reference point formed into the coined blade, the trimming line may be established with needed precision for producing matching blades of identical width and length and in the correct orientation relative to the top surface of the base in reference to the aforesaid stacking points.

With the above understanding of the operations by means of which the present invention may be practiced, those skilled in the art will understand how to adapt existing machines and/or to build other machines to carry out the method aspects of the present invention.

After the final trimming operations, the completed blade of FIG. 30 will then have the base portion 10b machined to size for assembly, such for example, as to form the driving and driven parts of gas turbines and for air compressor applications. For applications of this kind, blade manufacturing costs have been greatly reduced as a result of the present invention, and the blades resulting from the methods and apparatus described above are suitable for turbo-jet engine applications.

This application is a continuation-in-part of our application Serial No. 738,528, filed May 28, 1958, for Improved Method and Apparatus for Producing Blades, now abandoned.

1 What is claimed is:

1. The method of manufacturing a blade preform from a blade blank having an enlarged base portion and a centrally disposed extension of materially smaller crosssectional area and including angular transition regions between the base portion and said extension, which comprises suspending from said transition regions said preform by rounded convex surfaces of opposed dies, applying solely to the back surface of said base portion opposite the centrally disposed extension a force to move said preform along a metal-forming path extending intermediate said dies, developing from force opposing forces respectively directed wgularly toward said transition regions of said blade blank thereby to maintain said preform in position for continued engagement by said rounded surfaces of said dies during its movement along said metal-forming path, increasing said force applied to said back surface to metal-moving magnitudes, and concurrently increasing said angularly directed opposing forces in proportion to the quotient of said force applied to said back surface divided by the sine of the angle between a line normal to the direction of that applied force and the angular direction of each of said opposing forces, said angle decreasing as said preform moves through said metal-forming path, said applied force and said angularly directed forces of increasing magnitude moving metal in divided flow from said transition regions, some outwardly and some inwardly, relative to said extension to form rounded concave fillets from said transition regions with concurrent reduction in the cross-sec tional area of said extension adjacent to said fillets and with conccurent increase in the length of said extension.

2. In the method of claim 1, in which two roller dies are bodily moved toward each other to bring two rounded corners thereof into engagement with said shaped transition region, as said corners engage said fillets applying a compressional force to said back surface of said blade preform to press its top surface toward and against shoulder portions of said roller dies, rotating said roller dies to reduce outwardly from said region of reduced cross-sectional area of said airfoil section the thickness of the airfoil section and reversing said compressional force to maintain said blade preform under tension during rolling, said reversed force being applied generally tangentially to said roller dies to minimize curvature of the airfoil section of said blade during said rolling thereof.

3. In the method of claim 1, in which two roller dies are bodily moved toward each other to bring two rounded corners thereof into engagement with said smoothly curved fillets, as said corners engage said fillets applying a compressional force to said back surface of said blade preform to press its top surface toward and against shoulder portions of the dies to reshape said top surface including said fillets, rotating said roller dies toreduce outwardly from said region of reduced cross-sectional area of said airfoil section the thickness of the airfoil section, and reversing said compressional force to maintain said blade preform under tension during rolling, said reversed force being applied generally tangentially to said roller dies to minimize curvature of the airfoil section of said blade during said rolling thereof.

- 4. The method of claim 2 in which said rolled blade preform is disposed between two coining dies having opposed surfaces to impart to the surfaces of the airfoil section their final finished shape and having adjacent end surfaces which through curved edge portions are joined to said opposed surfaces, moving said coining dies toward each other to impart to said airfoil section its final finished shape, and concurrently with the movement of said coining dies toward each other applying to the back surface of said base a material-shaping force to reshape said top surface .into conformity with the end surfaces of said die and to reshape said fillets in conformity with said curved portions of said die.

5. The method of claim 2 in which said rolled blade preform is disposed between two coining dies having metal-shaping surfaces in planes generally normal each to the other, and upsetting the base top surface and fillet area simultaneously with the coining of the airfoil section.

6. The method of claim 2 in which said rolled blade preform has its airfoil se'ction disposed between the coining surfaces of coining dies, having their coining surfaces oriented in conformity with the aerodynamic configuration desired in the finished blank and in which the base top surface is disposed adjacent the end surfaces of the coining die, said end surfaces having shapes to establish the desired final shape of the top surface in relation to said aerodynamic configuration, the additional steps of upsetting the base top surface and fillet area by applying metal-shaping pressures to the back surface of the base while simultaneously coining between the coining surfaces said airfoil section to bring its aerodynamic surfaces into their final finished shape.

7. In a method of manufacturing a blade preform from a blade blank which in a transition region joining a base portion and an airfoil section thereof has a cross-sectional area which gradually increases from the crossrsectional area of the airfoil section to that of the base portion, the steps which comprise applying a force solely to the back surface of said base portion opposite said airfoil section for moving said blade blank along a metal-shaping path, applying to two opposite faces of said transition region reaction forces developed by said blank-moving force, and concurrently increasing the magnitude of said blank-moving force and said reaction forces with movement of said blank, said reaction forces being applied to said transition region by rounded fillet-forming surfaces of two dies which upon increase of said forces shape said transition region into smoothly rounded fillets, said rounded surfaces protruding toward each other to reduce the cross-sectional area of said airfoil section in the region immediately adjacent said fillets.

8. In a method of manufacturing a blade preform from a blade blank which in a transition region joining a base portion and an airfoil section thereof has a cross-sectional area which gradually increases from the cross-sectional area of said airfoil section to that of said base portion, the steps which comprise moving convex fillet-forming protuberances of two dies into engagement with opposite faces of said transition region intermediate the ends thereof, applying to the back surface of the base of said blade blank opposite said airfoil section the sole materialshaping force to move said blank bodily toward said protuberances while progressively decreasing the spacing between said protuberances, thereby to develop from said material-shaping force concave fillet-forming reaction forces, and shaping said transition region into smoothly minating in a region of reduced cross-sectional area jointly curved fillets extending from the base top surface and terformed by said protuberances.

9. The method of manufacturing a blade preform from a blade blank having an enlarged base portion, an airfoil section and transition regions between the base portion and the airfoil section which comprises applying solely to a back surface of the base portion of the preform opposite the airfoil section a force P to move the preform along a metal-forming path, developing from said force P opposing forces R respectively directed angularly toward a transition region of the blade blank lying between the base portion and the airfoil section thereof, said opposing forces being respectively directed toward said transition region of an angle a from a line normal to the direction of the application of the force P, said angle decreasing with movement of said blade blank along said metal-forming path, and concurrently increasing the force P to move said blade blank along said path while increasing the force R in proportion to the quotient of the force P divided by the sine of said angle oz, said forces R being applied to said transition region through die members, thereby to reshape opposite faces of said transition region into generally concave fillets.

10. The method of claim 9 in which said angle a is decreased from a small angle to a smaller angle during said reshaping of said opposite faces, and in which said faces terminate in a region of the airfoil section in which the cross-sectional area has been substantially reduced by said die members.

11. The method of claim 9 in which said angle a is,

id decreased from a starting angle to a finishing angle which fixes the length of said metal-forming path, said die members having protuberances which first form fillets and then reduce the cross-sectional area in the region adjacent said fillets by an amount related to the extent of change of said angle.

12. The method of claim 9 in which said angle a is decreased from a starting angle to a finishing angle which fixes the length of said metal-forming path, said die members having protuberances which during decrease of said angles are moved toward each other and against said transition region first to form fillets and thereafter to reduce the cross-sectional area of the airfoil section in juxtaposition with the fillets, and abruptly arresting the movement of said blade blank to predetermine the extent of the reduction in said cross-sectional area.

13. In a method of manufacturing a rolled blade preform from a blade preform having a base portion and an airfoil section interconnected by smoothly curved generally concave fillets and with a region of reduced crosssection in the region adjoining said fillets, the base por tion having a top surface adjacent said fillets, the steps which comprise relatively moving two dies, one toward the other to bring rounded corners thereof into said region of reduced cross-sectional area, seating said preform into said dies by applying to the base of said blade preform opposite the airfoil section a force which presses said top surface of said base against opposing shouldersurfaces of said dies, said dies having arcuate rolling surfaces, and rotating said dies in directions to reduce outwardly from said base the cross-sectional area of said airfoil section with concurrent reversal of said applied force to said base to place said airfoil section under substantial tension during said rolling thereof.

14. The method of claim 13 in which said dies after forced seating of their rounded corners against the fillets of said blade preform reshape the fillets prior to reversal of the force applied to said base.

15. The method of claim 13 in which said reversed force is applied to said airfoil section in a direction parallel to a tangent to that portion of the curved surface of the die engaging said airfoil section, the first of said dies being stationary, and the second of said dies being movable toward the stationary die along an arcuate path having its axis of rotation located in spaced relation from the line of action of said tensional force in the direction of said stationary die.

16. The method of claim 13 in which said relative movement of said two dies, one toward the other, is along an arcuate path and is characterized by the fact that the angle between a tangent to the arcuate path and a center line formed by a trace of the central airfoil-rolling plane between said arcuate rolling surfaces is less than 17. Apparatus for manufacturing from a blade blank having an enlarged base portion from which there extends angularly disposed transition regions merging into a centrally disposed extension from which there is to be produced an airfoil section, comprising supporting structure, a pair of dies havingrecesses in the die top surfaces extending only partially through the die, each recess defined by sides and a bottom, for receiving said base portion and also having adjacent the bottoms of said recesses opposed convex protuberances whose radial axes are transverse to the metal forming path of travel and disposed to engage said angular transition regions for suport of said preform, a pair of die-actuating levers supporting said dies with said protuberances facing each other and engaging said transition regions, said levers at the respective ends remote from said protuberances being pivotally connected to said supporting structure and extending angularly toward each other to form with a travel line interconnecting their pivot point a relatively small angle which decreases as said dies are moved through said metal-forming path, force-applying means adapted to engage the back surface of said preform opposite the centrally disposed extension for applying thereto a metalshaping force of increasing magnitude to lock said preform into position between it and said protuberances and for developing reaction forces from said levers angularly applied to said transition regions, said force applied solely to said back surface by the positive mechanical connection formed by said preform producing rotation of said levers for rapid increase of said reaction forces as said angle decreases to displace metal from said transition regions outwardly and inwardly thereof to lengthen said extension and to reduce the cross-sectional area of that extension in the region adjacent said transition regions, said rounded protuberances forming fillets connecting said region of decreased cross-sectional area and said base portion, said outward flow of metal from said transition regions filling said recess as said levers move to their final positions with said angle decreased to zero.

18. The combination of claim 17 in which stop means are provided for said members in their final positions for reducing to zero said reaction forces and for applying metal-upsetting forces to said base.

19. The apparatus of claim 17 in which said suporting structure is made of steel and which as a result of forces outwardly directed from said pivoted ends of said levers as said angle approaches zero enlongates rapidly to reduce the magnitude of said reaction forces applied to said transition regions, thereby limiting the maximum values which may be developed by said forces during the reshaping of said transition regions.

20. An apparatus for producing a blade preform from a blade blank which in a transition region joining a base portion and an airfoil section thereof has a cross-sectional area which gradually increases from the cross-sectional area of said airfoil section to that of said base portion, comprising a support, a pair of dies, a pair of dieactuating levers pivoted to said support at their remote ends and respectively supporting said dies in opposed relation to receive therebetween said blade blank, said dies being spaced away from said support so that upon rotation of said levers toward said support said dies move toward each other, and actuating means adapted to engage only said base portion of said blade blank to move it downwardly and concurrently to rotate said levers toward said support to move said dies toward each other, said dies having die top surfaces and recesses in the die top surfaces extending only partially through the dies, each recess defined by sides and a bottom for receiving said base portion and also having adjacent the bottom of said recesses outwardly protruding convex curved surfaces whose radial axes are transverse to the metal forming path of travel engaging and supporting said blade blank from said transition region to form smoothly curved fillets therefrom and to reduce the cross-section of a portion of said airfoil section during continued rotation of said levers toward said support.

21. An apparatus for producing a blade preform from a blade blank which in a transition region joining a base portion and an airfoil section thereof has a cross-sectional area which gradually increases from the cross-sectional area of the airfoil section to that of said base portion, comprising a support, a pair of dies having die top surfaces and recesses in the die top surfaces extending only partially through the dies, each recess defined by sides and a bottom for receiving said base portion and also having adjacent the bottom of said recesses convex protuberances whose radial axes are transverse to the metal forming path of travel, a pair of die-actuating levers supporting said dies with said protuberances facing each other, said levers at the ends remote from said protuberances being pivotally connected to said support and extending angularly toward each other with a separation distance between said protuberances for support by said protuberances of the blade blank from an intermediate portion of said transition region, and means adapted to apply alone to said base portion a force for rotating said levers in directions to decrease said separation distance and to develop reaction forces angularly directed toward said transition region, said force applied to said base portion being of a magnitude to shape the metal of said transition region into fillets corresponding in shape with said convex protuberances and concurrently to reduce the cross-sectional area of said airfoil section substantially below its initial cross-sectional area.

22. The apparatus of claim 21 in which said means for applying said force to said base portion includes a reciprocable member having a recess to receive therewithin said base portion.

23. The apparatus of claim 21 in which said support is made of steel which elongates within its elastic limit to regulate the maximum magnitudes of said reaction forces.

24. Apparatus for producing a blade preform from a blade blank which has a base portion and a portion depending therefrom to form an airfoil section, comprising a support, a pair of dies having die top surfaces and recesses in the die top surfaces extending only partially through the dies, each recess defined by sides and a bottom for receiving said base portion and also having adjacent the bottom of said recesses convex protuberances whose radial axes are transverse to the metal forming path of travel, a pair of die-actuating levers supporting said dies with said protuberances facing each other, said levers at the ends remote from said protuberances being pivotally connected to said support and extending angularly toward each other with a separation distance between said protuberances to receive therebetween said depending section, biasing means for biasing said levers to position where said separation distance is adequate for reception between said protuberances of said airfoil section, stop members for limiting rotation of said levers in directions to decrease said separation distance to predetermine said separation distance upon movement of said levers between an initial position and a final position, and means adapted to apply alone to said base portion a force for rotating said levers in said directions to decrease said separation distance for developing reaction forces for shaping a selected portion of said blade blank, said biasing means being effective upon removal of said force applied to said base portion to return said levers to their initial positions.

25. The apparatus of claim 24 in which an ejector is provided to engage the end portion of the airfoil section remote from said base portion, and resilient means for said ejector compressed upon movement of said blade blank toward said base and cooperating with said biasing means for said levers in moving them from their initial positions to their final positions and for releasing from said dies the blade preform.

26. In a method for manufacturing a blade from a blade blank having at least one base, an airfoil and a fillet area between a base top surface and the airfoil, the steps of: (1) reshaping the blade blank by partially forming the base top surface, and then forming the base top surface, the fillet area and a part of the airfoil adjacent the fillet area simultaneously so that the fillet area and the part of the airfoil adjacent the fillet area are smaller in cross-section than the airfoil, the radius of the fillet area being greater than the radius of a portion of the rollforming dies used subsequently to mate with the fillet area of the blade blank prior to roll-forming; (2) further reshaping and restraining the blade blank between the portion of the roll-forming dies prior to roll-forming motion of the dies by forcing the dies into the reshaped fillet area with a force at least equal to that required to permanently deform material of the blade blank and simultaneously forcing the base top surface and fillet area against the dies with a force less than that required to permanently deform the material of the blade blank, the reshaped fillet area being further reshaped by the portion of the dies forced into the fillet area; (3) and then roll-forming the

Claims (1)

1. THE METHOD OF MANUFACTURING A BLADE PREFORM FROM A BLADE BLANK HAVING AN ENLARGED BASE PORTION AND A CENTRALLY DISPOSED EXTENSION OF MATERIALLY SMALLER CROSSSECTIONAL AREA AND INCLUDING ANGULAR TRANSITION REGIONS BETWEEN THE BASE PORTION AND SAID EXTENSION, WHICH COMPRISES SUSPENDING FROM SAID TRANSITION REGIONS SAID PREFORM BY ROUNDED CONVEX SURFACES OF OPPOSED DIES, APPLYING SOLELY TO THE BACK SURFACE OF SAID BASE PORTION OPPOSITE THE CENTRALLY DISPOSED EXTENSION A FORCE TO MOVE SAID PREFORM ALONG A METAL-FORMING PATH EXTENDING INTERMEDIATE SAID DIES, DEVELOPING FROM FORCE OPPOSING FORCES RESPECTIVELY DIRECTED ANGULARLY TOWARD SAID TRANSITION REGIONS OF SAID BLADE BLANK THEREBY TO MAINTAIN SAID PREFORM IN POSITION FOR CONTINUED ENGAGEMENT BY SAID ROUNDED SURFACES OF SAID DIES DURING ITS MOVEMENT ALONG SAID METAL-FORMING PATH, INCREASING SAID FORCE APPLIED TO SAID BACK SURFACE TO METAL-MOVING MAGNITUDES, AND CONCURRENTLY INCREASING SAID ANGULARLY DIRECTED OPPOSING FORCES IN PROPORTION TO THE QUOTIENT OF SAID FORCE APPLIED TO SAID BACK SURFACE DIVIDED BY THE SINE OF THE ANGLE BETWEEN A LINE NORMAL TO THE DIRECTION OF THAT APPLIED FORCE AND THE ANGULAR DIRECTION OF EACH OF SAID OPPOSING FORCES, SAID ANGLE DECREASING AS SAID PREFORM MOVES THROUGH SAID METAL-FORMING PATH, SAID APPLIED FORCE AND SAID ANGULARLY DIRECTED FORCES OF INCREASING MAGNITUDE MOVING METAL IN DIVIDED FLOW SAID TRANSITION REGIONS, SOME OUTWARDLY AND SOME INWARDLY, RELATIVE TO SAID EXTENSION TO FORM ROUNDED CONCAVE FILLETS FROM SAID TRANSITION REGIONS WITH CONCURRENT REDUCTION IN THE CROSS-SECTIONAL AREA OF SAID EXTENSION ADJACENT TO SAID FILLETS AND WITH CONCURRENT INCREASE IN THE LENGTH OF SAID EXTENSION.

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