US2301140A - Forming blade holding core segments - Google Patents

Description

Nov. 3, 1942. A. F. PFEIFFER 2,301,140

FORMING BLADE HOLDING CORE SEGMENTS 8 Sheets-Sheet l Filed NOV. 24, 1941 Nov. 3, 1942. A. F. PFEIFFER 2,301,140

FORMING BLADE HOLDING CORE SEGMENTS Filed Nov. 24, 1941' 8 Sheets-Sheet 2 1942- A. F. PFEIFFER FORMING BLADE HOLDING CORE SEGMENTS 8 Sheets-Sheet 3 Filed Nov. 24, 1941 Nov. 3, 1942. 1 E 2,301,140

I FORMING BLADE HOLDING CORE SEGMENTS Filed Nov. 24, 1941 v I 8 SheetsSheet 4 /z 0 m -i11 /2z, 7

Nov. 3, 1942. A. F. PFEIFFER I FORMING BLADE HOLDING CORE SEGMENTS 8 Sheets-Sheet 5 Filed Nov. 24, 1941 /20 m ra v I! NOV. 3, 1942. PFElFFER 2,301,140

FORMING BLADE HOLDING -CORE SEGMENTS Filed Nov. 24, 1941 8 Sheets-Shet 6 a D m E: 1: I: 5::

' L L I Q 4 v s NOV. 3, 1942. A, pFElFFER 2,301,140

FORMING BLADE HOLDING CORE SEGMENTS Filed Nov. 24, 1941-v a Sheets-Sheet 7 Patented Nov. 3, 1942 FORIVHN G BLADE HOLDING CORE SEGMENTS Albert F. Pfeifler, West Allis, Wis., assignor to Allis-Chalmers Manufacturing Company, Milwaukee, Wis., a corporation of Delaware Application November 24, 1941, Serial No. 420,263

26 Claims.

This invention relates generally to elastic fluid turbine wheels, diaphragms and the like formed by embodying the buckets or fluid passage defining elements in a suitable core and by casting inner and outer diaphragm ring segment forming members integrally about the free end portions of the buckets or fluid passage defining elements which project from said core and more particularly to an improved core construction therefor.

In the construction of elastic fluid turbine diaphragm ring segments, for example, there are two known and accepted constructions which have heretofore been employed for correctly positioning and maintaining the partition or passage defining elements in their proper assembled relation within the core box during the ramming operation, namely: (1) indestructible metal filler blocks which are disposed between the free inner and outer end portions of adjacent blades and which may be removed either before or after the core is baked, and (2) destructible fiber side walls which are removable from the core only after the baking of the core is completed and which have formed therein exactly fitted alined openings through which the end portions of the partition or fluid defining elements extend.

The construction designated (1) above is time consuming and extremely costly since each filler block has to be accurately made and hand fitted to exact dimensions, since the filler blocks and partition elements have to be carefully assembled and the assembly accurately checked, and since all of these operations must be performed by persons having a high degree of skill. Moreover, as soon as a filler block becomes slightly worn, warped or otherwise deformed, it must be replaced and since deformation of the accurately fitted filler blocks frequently occurs, the cost of this type of construction is further increased. Furthermore, any error arising from the use of deformed or improperly fitted blocks or from the inclusion of foreign particles between the abutting surfaces on adjacent blocks and/or between the abutting surfaces on the blocks and the partition elements held therebetween is cumulative, thereby frequently requiring a completed or nearly completed assembly to be taken apart, the dimculty corrected, and the parts reassembled.

The construction designated (2) above is also time consuming and extremely costly. For ex-- ample, each fiber side wall must be accurately shaped to the requisite curvature and punch guides (one for each of the openings through which a partition element extends) must be hand filed therein and carefully checked before the partition element retaining openings can be punched therein. Moreover, the fiber side walls (two are required for each core) must be leftin place to support the partition elements when the core is being baked and the application of heat during the baking operation renders the fiber side Walls sufficiently brittle to prevent their removal Without destruction, thereby necessitating making a complete new set of fiber side walls for each core. Furthermore, after the fiber side walls have been removed from the core, fillet recesses must be cut by hand around both ends of each partition element Therefore, the primary object of this invention is to provide an improved construction for core segments embodying angularly spaced fluid pas.- sage defining elements which permit the core segments to be constructed with a minimum of skilled labor, which materially decreases thetime required to form a core segment, and which insures a high degree of accuracy heretofore unexcelled by highly skilled labor. I

Another object of this invention is to provide an improved core box structure embodying means permitting unskilled labor to rapidly and accurately position and secure in a core box an assembly comprising the fluid passage defining elements of a turbine diaphragm or wheel segment and the filler blocks adapted to be disposed in abutting relation between the end portions of adjacent elements.

Still another object of this invention is to provide an improved core box structure embodying means, which permits unskilled labor to rapidly and accurately position and secure in a core box; an assembly comprising the fluid passage defining elements of a turbine diaphragm or wheel segment and the filler blocks adapted to be disposed in abutting relation between the end portions of adjacent elements, which permits the box in-v eluding saidassembly to be readily rammed with core sand, and which permits the positioning and securing means to be readily removed from the box when the ramming operation is nearing completion without disturbing said assembly.

Still another object of this invention-is to provide an improved ring segment core embodying the fluid passage defining elements of a turbine diaphragm or wheel in that the core is provided with means operative to prevent a radial deformation of the core during the baking operation and to permit the baked core to be readilypicked up and bodily moved without danger of breaking same,

, The invention accordingly consists of the various methods, features of construction, combina-.

tions of elements and arrangements of parts as fully set forth in the appended claims and in the,

Fig. 2 is a section taken on line II-Ili of Fig. 1;-

Fig. 3 is a top plan view of a core box embodying the invention with parts removed or broken away to better show the construction;

Fig. 4 is a transverse section taken on line IVIV of Fig. 3;

Fig. 5 is a transverse section taken on line V--V of Fig. 3 with the lower jig holding ring segment and its transversely extending supporting strap removed;

Fig. 6 is a transverse section taken on line VIVI of Fig. 3; V

Fig. 7 is a transverse section taken on line VIIVII. of Fig. 3;

Fig. 8 is'a developed side view of the means for positioning and maintaining the blades in the core box;

Fig. 9 is a partial section taken on line IX-IX of Fig. 3 with the filler block clamping segments, the drag ring segments, and the filler blocks removed;

Fig. 10 is a developed side view illustrating the outer series of filler blocks in assembled relation with respect to each other and with respect to the end portions of the blades;

Fig. 11 is an end view of the right-hand end block shown in Fig. 10;

Fig. 12 is an end view of the left-hand end block shown in Fig. 10;

Fig. 13 is a top view of a fragment of the channel portion of the core box with blades and filler blocks therein shown in section;

Fig. 14 is a view similar to that shown in Fig. 13 with the blades and filler blocks shown in plan;

Fig. 15 is a section taken on line XVXV of Fig. 3 with the filler block clamping segments, the upper jig ring, and the blades and filler blocks removed;

Fig. 16 is a partial section taken on line XV'I-XVI of Fig. 15;

Fig. 17 is an exploded view of the end block structure of Fig. 16 to better show the arrangement of the coacting projections and recesses;

Fig. 18 is a partial section taken on line XVIII-XVIII of Fig. 15;

Fig. 19 is a bottom view of the top portion of the end block structure taken on line XIXXIX of Fig. 18;

Fig. 20 is a section taken on line XXXX of Fig. 3; d

Fig. 21 is a section taken on line XXIXXI of Fig. 3;

Fig. 22' is a complete section taken on line XV-XV of Fig. 3;

Fig. 23 is a development of a section of the inner portion of the core box taken on line XXIIIXX[II of Fig. 22;

Fig. 24 is a section similar to Fig. 21 showing the box partially rammed with the upper jig holding ring removed and the core arbor and the substitute filler block clamping segments in place;

Fig. 25 shows the structure of Fig. 24 inverted on a mold board;

Fig. 26 shows the inverted structure of Fig. 25 with the base ring segment and the lower jig holding segment removed;

Fig. 27 shows the structure of Fig. 26 with the with the blade holding and spacing jigs removed and with the second core arbor and the cope segments in place;

Fig. 28 is an end view of the left-hand end of the inverted core box with the end plates removed;

Fig. 29 is an end view of the left-hand end of thefinished core;

Fig. 30 is a side view of the inner side surface of the finished core;

Fig. 31 is a side view of the outer side surface of the finished core;

Fig. 32 is a partial plan view of the unbaked core;

Fig. 33 is an end view of the core shown in Fig. 32;

Fig. 34 is a plan View of the drag portion of the pattern used in forming a mold adapted to receive the core;

Fig. 35 illustrates a section of the drag portion of the pattern taken along the line XXXV-XXXV of Fig. 34 as it appears in a mold flask rammed with sand;

Fig. 36 is a sectional View showing the completed pattern supported in the drag flask;

Fig. 37 is a sectional view showing the completed mold with the core disposed therein;

Fig. 38 is a partial top view of the core box showing the manner in which the upper jig holding ring segment is secured in the core box;

Fig. 39 is a sectional view taken on line XXXIXXXXIX of Fig. 38;

Fig. 40 is an end view of the left-hand end of the core box showing the end plates in place; and

Fig. 41 is an enlarged view of the bottom portion of an intermediate filler block.

Referring to the drawings. Fig. 1 shows a turbine diaphragm segment I which was cast with the aid of a core structure embodying features constituting the invention. The diaphragm segment I, of which a transverse section is shown in Fig. 2, comprises a series of spaced curved passage defining elements 2 (hereinafter referred to as blades), an inner ring segment 3 and an outer ring segment i. The diaphragm segment I is constructed by forming a core 6 (see Figs. 29, 30, 31 and 3'?) in which the blades 2 are accurately held in predetermined spaced angular relation with the inner and outer end portions of the blades extending freely beyond the inner and outer side surfaces of the core and by casting integrally thereto, i. e., to the free end portions of the blades, the inner and outer ring segments designated 3 and 4, respectively. A complete diaphragm is usually made by casting two oversize segments which are then machined to provide two 180 segments having the requisite dimensions. However, neither the number of segments employed in forming a complete diaphragm nor the nature of the blades employed in forming the segments are essential features of this invention and a further description in this connection is believed unnecessary for a complete understanding of the core box structure 1 used in forming the core 6.

Referring particularly to Fig. 3, it is seen that the core box structure 1 comprises a base ring segment 8, a lower jig holding ring segment 9 disposed on said base ring segment in spaced concentric relation with respect to the side edges thereof, a pair of inner and outer blade positioning and holding jig segments H and I2, respectively, which are disposed on the jig holding ring segment 9 in spaced concentric relation with respect to the side edges of the said base segment and with respect to each other, a pair of inner and outer drag ring segments I3 and M, respectively, which are disposed on said base ring segment in spaced concentric relation with respect to said pair of jig segments and with respect to each other, the blades 2 which are positioned and held in predetermined spaced angular relation by the inner and outer jig segments H and I2, respectively, with a portion of the opposite end of each blade abutting the opposed channel forming side surfaces presented by the pair of inner and outer drag ring segments l3 and 4, respectively, the inner and outer series of filler blocks It and I1, respectively, which are disposed in spaced concentric relation between the inner and outer end portions of adjacent blades, the upper jig holdin ring segment I 8 which is disposed in spaced con centric relation between the opposed channel forming side surfaces presented by the inner and outer drag ring segments l3 and I4, and the inher and outer filler block clamping ring segments l9 and 2|, respectively, which are secured to the top portions of the inner and outer drag ring segments l3 and M in spaced concentric relation with respect to the upper jig holding ring segment H! and with respect to each other.

Referring also to Figures 4 and 5, it is seen that the base ring segment 8 may comprise a flat ring segment bottom member 22 having its ends rigidly connected by a cross member 23, and a pair of inner and outer base members 24 and 26 having similarly shaped top surfaces 21 and 28, respectively. Base members 24 and 2B are positioned on and secured to the bottom member 22 by any suitable means (not shown) and in spaced concentric relation with respect to the side edges thereof and with respect to each other so as to form therebetween a channel 29 adapted to snugly receive therein the lower jig holding ring segment 9. The jig holding segment 9 is properly positioned in the channel 29 with its top surface substantially flush with the surfaces of the uppermost steps on the base members 24 and 29. Referring also to Figs. 3, 5, 6 and 7, it is seen that the positioning means comprises a plurality of transversely extending straps 3| each of which is secured to the underside of the jig holding segment 9 by a cap screw 32 and each of which is disposed within a pair of radially extending alined rooves 33 and 34 provided in the stepped top surfaces of the base members 24 and 26, respectively, a plurality of pins 35 (see'Fig. 7) which extend downward from the underside of the jig holding segment 9 and into the sockets 36 provided in the bottom member 22, and a pair of removable rods 31 which extend through alined openings in the base members 24 and 26 and the jig holding segment 9 as is shown in Fig. 3. The bottom member 22 is provided, as shown in Fig. 6, with openings 38 into which the strap 3| and the head of the cap screw 32 project. The top surface of the inner and outer radially extending portions of the strap 3| which lie in the alined grooves 33 and 34 are stepped to form continuations of the stepped top surfaces 21 and 29 presented by the base members 24 and 2G, respectively, as is best shown in Figs. 3 and 6.

The lower jig holding ring segment 9 is provided in its top surface with a pair of inner and outer channels 39 and 4|, respectively, which are preferably of rectangular shape when viewed in transverse cross section and which are disposed adjacent the inner and outer edges of the jig holding segment 9 and in spaced concentric relation with respect to each other and with respect to the concentric surfaces provided by the stepped top surfaces of base segments 24 and 29,.respectively. The lower portions of the blade positioning and holding jigs H and I2 fit snugly within the inner and outer channels 39 and 4|, respec tively, as is clearly shown in Figs. 6 and '7 and are removably secured therein by means of a plurality of pairs of screws 42 which extend through pairs of bores 43 provided in the jig holding segment 9 and into the alined and internally threaded bores 44 and 46 provided in the bottom side of the inner and outer jig segments II and H, respectively, as is shown in Figs. 9 and 20. The portions of the inner and outer jig segments H and I2 which extend above the top surface of the J'ig holding segment 9 are provided with pairs of alined transverse notches 41 and 48 which terminate in identical undercut portions 49 and 5|, respectively, adapted to receive therein longitudinally spaced intermediate portions of the outlet edge of a curved blade as is best shown in Figs. 8, 9, 13 and 14.

In this connection, it should be particularly noted (see Fig. 8) that the undercut portions 49 and 5| are each defined by downwardly inclined opposed surfaces 52 and 59 and by an end surface 54; that the opposed portions of the surfaces 52 and 53 are substantially parallel and spaced apart a distance only slightly greater than the thickness of that portion of the outlet edge of the blade which is inserted therein; that the undercut portions of the pairs of notches are in radialialinement (see Figs. 3, l3 and 14); and that when the outlet edge portion of a curved blade is insertedtherein, the weight of the blade acts to hold (1) spaced intermediate portions of the outlet edge in engagement with the end surfaces 54, (2) spaced portions of the concave surface which are immediately adjacent said outlet edge portions, in engagement with the upper surface 52, and (3) spaced portions of the convex surface, which are remote from the said outlet edge portions, in engagement with the lower surface 53 as is clearly shown in Fig. 8. In addition, it should also be particularly noted (see Fig. 9) that the blades 2 have an intermediate outlet edge portion of reduced thickness, and that therefore only relatively small portions of the outlet edge of each blade on either side of the jig holding segment 9 are shown as actually engaging the top steps of the surfaces 21 and 29. However, when blades are employed which have an outlet edge of substantially'uniforrn thickness, it should be apparent that the entire width of the said top steps would be engaged by the overlying edge portions of each blade. The arrangement is preferably such that the top surfaces of the top steps are substantially flush with the top surface of the jig holding segment 9 and that the'lowerrnost edges of the undercut portions 49 and 5|, i. e., the edges formed by the junction of the lower surface '53 and the end surface 54, are also substantially flush with the top surface of the jig holding segment 9 and with the top surfaces of the said top steps. Consequently, when the thickness of the outlet edge of each blade is equal to the width of the end surface 54, portions of the outlet edge of each blade will engage the top surfaces of the said top steps in the manner just described. Obviously, if the thickness of the outlet edge of the blade is made greater than the width of the end surface 54, the outlet edge of the blade cannot be inserted into the undercut portions of the notches without deforming the notch or blade or both, and the preferred procedure in order to allow for reasonable manufacturing tolerances is to make the outlet edge of the blade just equal to or slightly less than the width of said end surface. Therefore, in actual practice, the outlet edge of the blade may be spaced above the top surfaces of the said top steps a distance equal to the maximum permissible tolerance.

Referring particularly to Fig. 7, it is seen that the inner and outer drag ring segments I3 and I4 are provided with stepped top and. bottom surfaces 56, 51 and 53, 59,, respectively, and that the bottom surfaces of the segments I3 and I 4 are provided with internally threaded bores 6| and 62, respectively, arranged for alinement with the bores 83 and 64 in the base members 24 and 25 which bores are in turn alined with the bores 65 and 6! provided in the .bott om.member 22. Bolts 68 and 59 removably secure the drag ring segments I3 and I 4 in spaced concentric relation on inner and outer concentric portions of the stepped top surfaces 2'! and 28 which are presented by the base members 24 and26, respectively. The radial width of the drag ring segments is less than that of the base members 24 and 26 and the opposed channel forming side surfaces of the segments I3 and I l coact andform with exposed portions of the stepped top surfaces 27 and 28 spaced concentric surfaces adapted to position and retain thereagainst the inner and outer series of filler blocks I and I I, respectively, which are to be assembled in spaced concentric relation between the inner andouter end portions of adjacent blades. The length of the blades 2 and the spacing of thedrag ring segments I3 and I4 are such that when the outlet edges of the blades are inserted in the pairs of alined notches 41 and 48 which act to correctlyposition and hold the blades in a predetermined spaced angular relation, a portion of each end of each blade abuts the adjacent channel formingside surface presented by said drag ring segments as is best shown in Figs. 13 and 14. The lower step of the top surfaces 56 and 58 of the drag rings I3 and I4, respectively, are provided with metal facing ring segments 7 55 and 60, respectively, which are preferably removably secured thereon by any suitable means such as the countersunk screws 65. V v j Referring to Figs. -14, inclusive, and 4|, it is seen that the outer series of filler blocks II comprises the end blocks 1B and ,II and a plurality of identical intermediate blocks I2. Each of the blocks III, II and I2 has stepped top and bottom surfaces I3 and I4, respectively, which are similar, i. e., all steps onthe top surfaces are identical and all steps on the bottom surfaces are identical, and the outer side surfaces of these blocks are preferably made to conform with the curvature of the inner side surface of the outer drag ring segment I4 as is best seen in Figs. 13 and 14. The end block I0 has a plane outer end surface 89 and an oppositely facing inner end surfacel'E comprising aplane radially extending top portion I5, a concave radially extending intermediate portion 11 which conforms with and is adapted toengage the convex surface of a blade 2, and a bottom portion including a radially extending edge m and a plane radially extending surface I9. The edgeI8 is formed by the intersection of the concave surface ,portion I7 and that portion of the stepped bottom surface I4 which is adapted to engage thetop step of the surface 23 on the bottom member 26. The top portion of the block II! is of greater radial thickness than the bottom portion thereof and its inner side surface BI is preferably formed by upper and lower plane surfaces being connected by, a portion of compound curvature as shown in Fig. 11. The lower portion cf the concave surface 11 is extended inwardly a slight distance beyond the lower portion of the inner side surface BI so as to form therewith a fillet forming projection 82.

Each of the intermediate blocks f2 has an inner end surface 83 which is identical to the surface I5 on the end block 18 and an outer end surface 84 comprising a plane radially extending top portion 86 which is complementary to the similar surface It on the end block IS, a convex radially extending intermediate portion 8! which conforms with and is adapted to engage the concave surface of a blade 2, and a bottom portion including the plane radially extending surfaces 88, 89 and 90 as best seen in Fig. 41. The top portions of each block I2 are also of greater radial thickness than the bottom portions thereof and its inner side surface 8|, which is formed in the same manner as the side surface til on the block I0, is provided with a pair of inwardly extending fillet forming projections 92 and 93 which merge into a single projection at the toe of the block as is clearly shown in Fig. 10 and Fig. 41. The fillet projection 92 conforms with the similar projection 82 on the end block I51. The end block H has a plane outer end surface 9 and an oppositely facing inner end surface 86. The surfaces 94 and 98 are identical to the outer end surfaces 88 and 84 on the end and intermediate blocks I0 and I2, respectively, and a repetition of the detailed description of such surfaces is believed unnecessary for a complete understanding of the invention. In addition, the top portion of each block II is of greater radial thickness than the bottom portion thereof and its inner side surface 9! is provided with an inwardly extending fillet forming projection 98 corresponding to the fillet forming projections 93 on the intermediate blocks I2. The side surface QI is also formed by plane and curved surfaces as set forth in the description of end block IS.

The inner series of filler blocks It comprises, as best shown in Figs. 13, 14 and 23, the end blocks IGI and IE2 and a plurality of intermediate blocks H13. Each of the blocks IfiI, M32 and IE3 has identically stepped top surfaces hi l and identically stepped bottom surfaces I which are adapted to engage the exposed portion of the stepped surface 21 on the base member 24. The blocks Ifll, I82 and IE3 have inner side surfaces which are made to conform with the outer side surface of the inner drag ring segment I3 and have outer side surfaces I96, I07 and H0 which are similar to the inner side surfaces SI, 92 and 91,, respectively, on the outer blocks IE, II and I2. The end block IIlI has a plane end surface I58 and an oppositely facing inner end surface I39 which end surfaces are similar to the outer and inner end surfaces 89 and i5, respectively, on

the end block I0. The end block I62 has oppositely facing inner and outer end surfaces III and H2 of which the surface IE2 is similar to the corresponding end surface S t on the outer end block II. However, the end surface III, which is somewhat similar to the end surface 98 on the end block II, differs therefrom in that the plane and convex portions thereof are made to extend parallel to the plane and concave portions of the surface 83 on the intermediate block I2 as is best shown in Fig. 13. The intermediate blocks I03 have oppositely facing end surfaces H3 and H4 with respect to which the surface H3 is identical to the surface I @9 on the end block IUI and the surface H4 is identical to the surface I I I on the end block I IE2. In other words, the surface III on the end block I62 is made to extend parallel to the surface I I3 on the adjacent intermediate block I03. This construction which permits the inner filler blocks to be withdrawn from between the blades by an inward radial movement thereof is clearly shown in Figs. 13, 14 and 23.

Referring to Figs. 3, 15, 16, 17, 18, 22 and 23, it is seen that the end filler blocks and IM of alined notches 41, 48 and the arrangement of are held from being pushed out the end of the core box by means of inner and outer end blocks H6 and H1 having plane inner end surfaces H8 and H9, respectively. The arrangement is such that the plane end surface I I8 of block H6 is disposed in abutting relation against the plane end surface of the inner clampingring I9, the inner drag ring segment I3 and against a portion of the plane end surface I08 of the end filler block IOI, and that the plane end surface H9 of block H1 is disposed in abutting relation against the plane end surface of the outer clamping ring 2|, the outer drag ring segment I4 and against a portion of the plane end surface 80 of the end filler block 18. Each of the blocks H6 and I I1 comprises separable top and bottom portions I20, I2I and I22, I25, respectively. The top portion I is provided on its underside with a projection I23 adapted to fit within the recess I24 provided in the top surface of thebottom portion [2i and the top portion I22 is provided on its undersidewith a-projection I26 adapted to fit within the recess I21 provided in the top surface of the bottom portion I25. The underside of the bottom portions I2I and I25. are provided with projections I28 and I29 adapted to fit within recesses 1 HI and I32, respectively, which arerformed by blocks I33 and I34 being secured on the lowermost step of the surfaces 21 and 28 in spaced opposed relation with respect to the adjacent end of the drag ring segments I3 and I4, respectively, as is best shown in Figs. 15 and 16. Each end of the drag ring segments I3 and I4 is provided with extensions I36 and I31, respectively, which present plane opposed side. surfaces I38 and I39 adapted to engage the plane side surfaces MI and I42 on the end blocks H6 and H1, respectively, and prevent a transverse movement of said end blocks relative to the drag ring segments and the end filler blocks I3, 2' I4 and 10, I02, respectively. The extensions I36.

and I31 terminate flush with the plane outer end surfaces of .the blocks H6 and H1 and with the plane end surfaces presented by the base members 24 and 26 as is best shown in Figs. 3, 15, 16, 18 and 22, and a pair of coactingend plates I43 and I44 (see Fig. 40) are adapted to be re movably secured in abutting relation against said surfaces by means of the stud bolts I46.

Assuming that the core box has been com pleted to the extent indicated in Figs. '1 and 15; i. e., that the lower jig holding segment 9 includ ing the jigs I I and I2 has been inserted in the base ring segment 8, that the drag ring segments have been positioned onand secured to the base ring segment 8, and that the end blocks llli and H1 are in place; the next step is to posithe jigs II and I2 and the end filler blocks 10 and IN is such that when a blade 2 is positioned and held by the said adjacent pair of notches, the end portions of the convex surface of the blade abut the entire concave portions of the inner end surfaces 15 and I09 on the end filler blocks 10 and IN, respectively, as is clearly shown in Figs. 10 and 23. An outer intermediate filler block 12 is then positioned in the box with its outer side surface abutting the inner side surface of the drag ring segment 14 and with its stepped bottom surface 14 engaging the exposed portion of the stepped surface 28 on base member 26 and so that the outer end surface 84, which comprises the plane surface 80, the convex surface 81, and the plane surface 83, abuts the plane surface 16 on the endfiller block 10, the outer concave end portion of the blade 2, and the outer end portion of the outlet edge surface of the blade 2, respectively, as is clearly shown in Figs. 10, 13 and 14. An inner intermediate filler block I03 is then positioned in the core box with its bottom surface I05, its inner side surface, and its end surface H4, which includes plane and convex surfaces corresponding to the surface portions 86,

81, 88, 89 and 80 on the outer filler block 12,

abutting the exposed portion of the stepped surface 21, the outer side surface of the drag ring segment I3, the inner margin of the plane top portion of the surface I89 on the end block IIH, the inner end margin of the concave surface of the blade 2, and the inner end margin of the outlet edge surface of the blade 2, respectively, as is clearly shown in Figs. 13, 14 and 23. In actual practice, an inner and an outer filler block are placed simultaneously within the core box in the positions just described and the blade and filler block assembly is continued by alternately inserting a blade and a pair of inner and outer intermediate filler blocks. When the requisite number of blades has been inserted as just described, the assembly is completed by inserting the inner and outer end filler blocks I02 and H which are held in place in the core box by a retaining end block assembly which is identical to that described for the end filler blocks 10 and IOI. Consequently, a further description in this connection is believed unnecessary for a complete understanding of the invention.

When the filler block, the blades and the retaining end block assemblies have been completed as just described, the blades 2 are securely locked in their assembled relation by placing thereon, i. e., on their inlet edges, the

' upper jig holding segment I8 which has secured tion the end filler blocks 10 and IOI in the.

core box with their stepped bottom surfaces 14 and, I05 engaging the exposed portions of the stepped surfaces 28 and 21, respectively, on the base members 26 and 24, with their outer and inner side surfaces abutting the inner and outer side surfaces, respectively, of the drag ring seg ments I4 and I 3, and with their plane end surfaces 80 and I88 abutting the exposed portions of the plane inner end surfaces H9 and H8 on the end blocks I I1 and H6 as is best shown in Figs. 22 and 23. The next step is to insert the outlet edge of a blade 2 into the adjacent pair in its underside, a projecting jig segment I41 provided with notches I48 arranged to engage the inlet edges of the blades 2 in the manner best shown in Figs. 8 and 9. preferably positioned on the underside of the jig holding segment I8 by means of a channel I49 which is formed midway between the side edges of the segment I8 and which is adapted to snugly receive therein, a portion of the jig segment I 41. The jig segment may be removably secured in the channel I43 by any suitable means, such as one or more of the screws I50 shown in Figs. 8 and 20. The upper jig holding segment I8 is positioned directly above the lower jig holding segment 9 and each end is rigidly connected to the underlying end of the segment 9. The connecting means (see Fig. 8) comprises an internally threaded bore I5I which extends The jig I41 is throughthe segment I8,1.a non-threaded bore ltllwhich extends through 'the segment 9 in alinement withnthe bore and which terminates in an upper counterbored portion I53, a stud having an upper threaded portion I54 extending within the bore I5I, an enlarged intermediate .portion I56 which fits within the counter-bore I53 and which abuts the underside of thesegment ii andanexternally threaded reduced portion I51 which extends through the bore I52 and is engaged by a nut I58. It should be particularly noted that thejig I51 engages the-inlet edge, of each blade 2 at ,a point which is midway between the; ends of the blade and whichis also midway between the longitudinally spacedportions of the outlet edge of the blade engaged by a pair of the .alined notches ll and.

spectively, on the inner and outer drag ring seg-.

mentswlth the stepped bottom surfaces. l 5% and Itl engaging the complementary stepped top surfaces Iil l and I3 presented by the inner and outer series of fillerv blocks it and ii, respectively, as shown in Fig. .21. The top surfaces of the clampingring segments is and 26 are substantially flush with the plane surfaces presented by top steps of the surfaces 56 and 581 on the drag.

holding segment 28 so as to facilitate the ramming operation. .Beferring to Figs. 38 and bit is seen that the upper surfaces of the filler blcclr clamping segments I9 and H are provided with a pair of radially alined grooves I63 .and ltd-and.

the top surface of the upper jigholding segment I3 is provided witha similargroove ltia arranged for alinement with the grooves i639 and M53.- A metal strap IE7 is inserted in said grooves and is removably secured to the filler block clamping segments I9 and ii by any suitable means such as the screws I58 so as to prevent the intermediate portion of the jig holding segment I8 from springing upward relative to the inlet edges of the blades. The end piatesMB and I44 are now secured to the ends of the box (see Fig.40) thus rendering the box ready for the initial ramming operation. 1 7

Sand or other suitable core forming material, hereafter referred to as sand, is now rammed by hand or blown into the space between the blades until the box is filled with sand to a point slightly above the inlet edges of the blades, i. e., the edges engaged by the-jig I li, whereupon the end plates i 33 and Hi l are partially removed which permits the upper jig holding segment I3 and the jig to a depth sufficient to support the metallic ring segment arborIES out of contact with the inlet edges of the blades as shown in Fig. 24. Usually a depth of approximately one-quarter of an inch is sufficient. The ends of the arbor ltd are removably connected together: by :a =tie= rod-4110. 2: It shouldflalsobe' noted, particularzzreferenceis being had to Fig. 24, that the filler block clamp-.

ing segments, which were removed. either when i the upper'jig holding segment; I8- was-.,removed or after the arbor lfifirwasr placed in -the' box; have been replaced by a new set ,of clamping segr-z ments iii and H2 which differ from segments.

l9 and 2 I only inthat their opposed side surfaces:- "5 converge upwardly with respectgto each other.:. The ramming of the core box is then :continued until, the boxiis filledwith sandto' a. point sub-.

stantially flush with, the. topxs'surfacesr-of the: clamping segments Ill "and I12." and the molds" board. H3115 placed overthecorebox andJtha entire structure is then inverted'to the position: 2.

shown in,Fig.'.;25.

The next stepin completing the; core is to are-- move thebase segment 8 which :includes the 1: bottom member EZ and the inner and outer base: members Hand 26 from the drag-ring segments 1 l3 and I4 and from the lower jig holding seg-..

ment 9 and the strapsil which. are secured '1 This step is readily accomplished byv thereto. first. removing the bolts 68*and t9 ..(see.Fig;.7) and then lifting the entire basesegment. Next,

the lower-:jig hold segment. 9 is removed from i the jigs. II and I2 which is readily accomplished. a by first removing the screws G2 and thenbodilyr lifting theujig holding segment 9 together with, the straps 3i which, are secured thereto. I When this has been done, the screws 42 are then. in-

serted in the jigs I I and I 2.1 The resulting strucel;

ture conforms withthat shown in Fig..26." Them: jigs II and I2 cannow be readily removedffrom;v the outlet edges of the blades 2 and without af-.

fecting .a movementjthereof ,simply'by' grasping:

or tapping the screws 42 to effect a movement of 1 the jigs circumferentially and upward with're-v spect to the outlet edges of the blades .(the neces-.

sary direction of movement is apparent from a consideration of Fig; 8 when inverted) a sufficient distance to. free the undercut portions of the. pairs of notches 4"! and 48 'from'the outlet edges of the blades.

The core box is then completed preparatory to the final ramming operation, by placing on. the drag ring. segments, the inner and outer cope segments I'l land I15, respectively, which have: the underside of their end portions provided with" recesses IT! and I78, respectively, adapted to,

receive therein the projections I29 and I28 on I the bottom .endblock portions I25 and I2I, re-I spectively. The bottom surfaces of the cope seg-.

ments I74 and I15 are'identical to the stepped,

surfaces. 21 and 28 presentedby. thebase mem-- bers 24 and 26, respectively, and the cope segments are positioned and removably' held with their bottom' surfaces engaging the'drag ring segments [3 and I4 and the inner and outer series of filler blocks-I6 and I! by any suitable meanssuch as the. dowel pins I83 shown in Fig. 27. The opposite end portions of the cope segment I'M coact with the endsof the drag ring segment. It, the bottom end block portions I25 (there being one such blockportion at each end of the'box) the plane end surfaces on the filler blocks It and H, and. with the inner surfaces of the end plates andforms therewith a space (see Fig.28) into which sand is rammed to form the laterally extending projection I19 adjacent the ends of-the core Gas shown in Figs. 29, 30, 31 and 33. The opposite ends of the-cope segment I75 coact with theends of the drag ring segment I3,

the bottom-end block portions I2I (there being one such block portion at each end of the box), the plane end surfaces on the filler blocks IOI and I52, and with the inner surfaces of the end plates and forms therewith a space (see Fig. 28) into which sand is rammed to form the laterally extending projection ISI adjacent the ends of the core 6 as shown in Figs. 29, 30, 31 and 33.

The outlet edges of the blades are now covered with sand (the end plates I43 and I44 having been partially removed to permit the removal of the jig holding segment 9 and the jigs I I and I2) and ring segment arbor I82, which is similar to the arbor I59, is placed thereon and the ends of the arbor are removably connected together by a tie rod I83 which is also similar to tie rod I10. The core box structure shown in Figs. 2'7 and 28, is now dismantled except for the inner and outer series of filler blocks I 6 and I1 and the filler block clamping segments HI and I12 which are preferably made of metal, such as aluminum, so as to also function as drying segments, by removing, in the order named, the end plates I43 and I64, the cope segments I14 and I15, the

drag ring segments I3 and I4, and the portions of the end blocks designated I2I and I25. The core together with the remaining portions of the core box is shown in Figs. 32 and 33. The core is now ready for baking and this is accomplished by placing the structure shown in Figs. 32 and 33 in a suitable oven (not shown) wherein the core is heated to and maintained at the requisite temperature for a predetermined time. Prior to the insertion of the core structure within the baking oven, the filler blocks, which are also made of metal such as aluminum to facilitate drying, are preferably withdrawn from the core a slight distance in the radial direction in order to prevent the expansion of the blocks from eX- erting a, force on the blades tending to move same. Withdrawal of the inner series of blocks in the radial direction is permitted by forming the end surface II4 substantially parallel to the surface H3 as is best shown in Figs. 13 and 23. In addition, the connections between the ends of the arbors I39 and I82 and the ends of the tie rods I19 and I83 are loosened in order to permit the free expansion thereof during the baking operation to thereby prevent damage to the core. After the core has been baked and cooled, the inner and outer series of filler blocks I6 and I1 are entirely removed and the connections between the ends of the arbors I69, I82 and the ends of the tie rods I19, I83 are again made secure in order to aid in preventing deformation of the core while it is being removed from the mold board and placed in the mold. The filler block clamping and drying segments HI and I12, which also function as a support for the filler blocks and the core as shown in Fig. 33, remain on the mold board I13 when the core is removed.

The dismantled core box structure including the previously used filler blocks and a new set of blades can be readily reassembled and a new core segment quickly formed in the manner just described. Obviously, no particular skill is required in this connection, and as a result the core segments can be rapidly formed with a minimum of expense, thereby materially reducing the cost of making cast diaphragm segments. In addition, the accuracy of diaphragm segments cast with the aid of cores made in accordance with this invention has in all cases been equal or superior to those made with cores constructed by highly skilled mechanics in accordance with the methods heretofore employed.

Referring to Figs. 34 and 35, it is seen that the drag portion I84 of the pattern, which is preferably used in forming a mold adapted to receive the core 6 preparatory to casting the diaphragm segment I shown in Figs. 1 and 2, comprises the inner and outer segments I86 and I81 for producing in the mold spaces corresponding to the portions of the diaphragm segment designated 3 and 4, respectively, a plurality of gate forming portions I88 which extend radially outward from the point at which the metal is to be introduced to the inner periphery of the segment I83, a plurality of radially extending gate forming bridging members I89 arranged to connect outer portions of the inner segment I86 with the outer segment I81 across the core space forming portion I9I, and the match board I92. The first step in forming the mold is to place the drag portion I84 on a mold board I93, then place a flask I94 therearound and ram the same with sand to produce the structure shown in Fig. 35. When this has been done, the flask is inverted on the mold board, the match board I93 removed from the drag portion I84, and the cope portion I95 of the pattern is added to produce the structure shown in Fig. 36. The next step is to place the cope flask I96 on the flask I94, ram the same with sand, lift the flask I96 from the flask I94, remove the pattern from the flask I94, place the core blocks I91 and I98 in the space adapted to receive the core 6, place the core 6 in said core receiving space, insert the core blocks I99 and 20I, and place the flask I96 on the flask I94 which completes the mold as shown in Fig. 37. The metal is poured into the mold through the central sprue 202 and after the casting operation has been completed and the casting cleaned, all that remains to be done is to machine finish the casting to the desired dimensions. The pattern structure and the manner in which the mold is formed are merely illustrative of a practical construction for using a core formed in accordance with this invention, and it should therefore be understood that it is not desired to limit the invention to the exact methods and details of construction herein shown and described as various modifications within the scope of the appended claims may occur to persons skilled in the art.

It is claimed and desired to secure by Letters Patent:

1. In a core box for use in forming turbine blade holding core segments embodying spaced curved blades extending transversely therethrough and presenting inner and outer free end portions adapted to have inner and outer ring segments cast integrally thereto, a bottom and drag ring construction comprising a base ring segment, a pair of inner and outer drag ring segments disposed on said base ring segment adjacent the edges thereof and in spaced concentric relation with respect to each other, and a pair of inner and outer jigs disposed on said base ring segment between and in spaced concentric relation With respect to said pair of drag ring segments and in spaced concentric relation with respect to each other, said pair of jigs being shaped to engage longitudinally spaced intermediate edge portions of blades inserted therein and to thereby position and firmly hold the blades in a predetermined angular relation.

2. In a core box for use in forming turbine blade holding core segments embodying spaced curved blades extending transversely therethrough and presenting inner and outer free end portions adapted to have inner and outer ring segments cast integrally thereto, a bottom and drag ring construction comprising a base ring segment, a pair of inner and outer drag ring segments disposed on said base ring segment adjacent the edges thereof and in spaced concentric relation with respect to each other, said drag ring segments coacting and forming with said base ring segment spaced concentric surfaces shaped to position and retain thereagainst inner and outer series of filler blocks, and a pair of inner and outer jigs disposed on said base ring segment between and in spaced concentric relation with respect to said inner and outer filler block positioning and retaining surfaces and in spaced concentric relation with respect to each other, said pair of jigsbeing shaped to engage longitudinally spaced intermediate, edge portions of blades inserted therein and to thereby position and firmly hold the blades in a pre-,

determined angular relation.

3. In a core box for use in forming turbine blade holding core segments embodying spaced curved blades extending transversely therethrough and presenting inner and outer freeend portions adapted to have inner and outer ring segments cast integrally thereto, a bottom and drag ring construction comprising a base ring segment, a pair of inner and outer drag ring segments disposed on said base ring segment adjacent the edges thereof and in spaced concentric relation with respect to each other, said drag ring segments coacting and forming with said base ring segment spaced concentric surfaces shaped to position and retain thereagainst inner and outer series of filler blocks, and a pair of inner outer jigs disposed on said,

base ring segment between and in spaced concentric relation with respect to said inner and outer filler block positioning and retaining surfaces and in spaced concentric relation with respect to each other, said pair of jigs being shaped to engage longitudinally spaced intermediate edge portions of blades inserted therein and to thereby position and firmly hold the blades in a predetermined angular relation, and said pair of drag ring segments being spaced apart a distance commensurate with the length of the blades to be positioned and held in said pair of jigs so as to form with the exposed top portion of said base ring segment and with said jigs a channel in which the blades and filler blocks can be quickly and accurately assembled simply by alternately placing in abutting relation, on said concentric positioning and retaining surfaces and in said pair of jigs, a pair of inner and outer filler blocks and a blade, respectively.

4. In a core box for use in forming turbine blade holding core segments embodying spaced curved blades extending transversely therethrough and presenting inner and outer free end portions adapted to have inner and outer and firmly, hold thehbla'des ina predetermined a mia;

In a core box for use in forming turbine blade holding core segments embodying spaced curved blades extending transversely therethrough and presenting inner and outer free portions adapted to have inner and outer ring segments cast integrally thereto, a bottom and drag ring construction comprising inner and outer base members disposed in spaced concentric relati-on, a jig holding ring segment disposed between said base members, a pair of inner and outer jigs disposed in spaced concentric relation on thetop portion of said jig holding ring segment, saidlpair of jigsbeing shaped to engage longitudinally spaced intermediate edge portions of blades inserted therein to thereby position and firmly hold the blades in a predetermined angular relation, and a pair of inner. and outer drag. ring segments disposed in spaced concentric relation and coacting with said base members to form therewith spaced concentric surfaces shaped to position and retain thereagainst inner and outer series of filler blocks adapted to be assembled between the inner and outer end portions of blades held in said pair of jigs.

6. In a core box for use in forming turbine ladeholding core segments embodying spaced curved blades extending transversely therethrough and. presenting inner and outer free end portions adapted to have inner and outer ring ment, said pair of jigs being shaped to engage longitudinally spaced intermediate edge portions of blades inserted therein to thereby position and firmly hold the blades in a predetermined angular relation, and a pair of inner and outer drag ring segments disposed in spaced concentric relation and coacting with said base members to form therewith spaced concentric surfaces shaped toposition and retain thereagainst inner. and outer series of filler blocks adapted to bev assembled between the, inner and outer endportions of blades held'in saidpair of jigs,

.said jigs being removably secured tosaid jig holding ring segment, said jig holding. ring segmentibeing removably secured to said base members, and said base members being removably secured relative to said pair of dragv ring segments so that when the core box is inverted said base members can be removed from said jig holding, ring segment and from their coacting relation Withsaid drag segments, said jig holding ring segment can then .be removed from saidpair of jigs, and said pair of jigs can then be removed from the blades inserted therein.

'7. In a core boxfor use in forming turbine blade holding core segments embodying spaced curved blades extending transversely there- ,througlr and: presenting inner and outer free end portions adapted to have inner andputer ring segments cast integrally thereto, a bottom and dragoring construction comprising inner and outer base members disposed inspaced concentric relation,.a jig holding ring segment disposed between .saidbase members, a pair of inner and outer jigs, disposed in spaced concentric relation on; the ,topportion of said jig. holding ring segment, said pair .of jigs being shaped to en-- gage longitudinally; spaced intermediate edge portions of blades inserted therein to thereby position and firmly hold the bladesin a predetermined angular relation, a pair of inner and outer drag ring segments disposed in spaced concentric relation and coacting with said base members to form therewith spaced concentric surfaces shaped to position and retain thereagainst inner and outer series of filler blocks adapted to be assembled between the inner and outer end portions of blades held in said pair of jigs, and said pair of drag rings being spaced apart a distance commensurate with the length of the blades to be positioned and held in said pair of jigs so as to form with the exposed top portions of said base members and with said jig holding ring segment and jigs a channel in which the blades and filler blocks can be quickly and accurately assembled simply by alternately placing in abutting relation on said concentric positioning and retaining surfaces and in said pair of jigs a pair of inner and outer filler blocks and a blade, respectively.

8. In a core box for use in forming turbine blade holding core segments embodying spaced curved blades extending transversely therethrough and presenting inner and outer free end portions adapted to have inner and outer ring segments cast integrally thereto, a bottom and drag ring construction comprising inner and outer base members disposed in spaced concentric relation, a jig holding ring segment disposed between said base members, a pair of inner and outer jigs disposed in spaced concentric relation on the top portion of said jig holding ring segment, said pair of jigs being shaped to engage longitudinally spaced intermediate edge portions of blades inserted therein to thereby position and firmly hold the blades in a predetermined angular relation, a pair of inner and outer drag ring segments superimposed in spaced concentric relation on portions of the tops of said base members and forming with the exposed portions of the tops of said base members spaced concentric surfaces shaped to position and retain thereagainst inner and outer series of filler blocks adapted to be assembled between the inner and outer end portions of blades held in said pair of jigs, and said pair of drag rings being spaced apart a distance commensurate with the length of the blades to be positioned and held in said pair of jigs so as to form withjthe exposed top portions of said base members and with said jig holding ring segment and jigs a channel in which the blades and filler blocks can be quickly and accurately assembled simply by alternately placing in abutting relation on said concentric positioning and retaining surfaces and in said pair of jigs a pair of inner and outer filler blocks and a blade, respectively.

9. In a core box for use in forming turbine blade holding core segments embodying spaced curved blades extending transversely therethrough and presenting inner and outer free end portions adapted to have inner and outer ring segments cast integrally thereto, a bottom and intermediate edge a trie relation on and forming with the top por- 75 tion of said base ring segment spaced concentric surfaces shaped to position and retain thereagainst inner and outer series of filler block's adapted to be assembled between the inner and outer end portions of blades held in said pair of jigs, blades held in said pair of jigs and inner and outer series of filler blocks disposed on said positioning and retaining surfaces and between the inner and outer end portions of said blades, removable clamping means superimposed on said series of filler blocks in spaced concentric relation, and a jig ring segment removably secured in spaced concentric relation between said clampin means and the upper portions of said drag rings and in engagement with an intermediate portion of the adjacent edge of each of the blades held in said pair of jigs.

10. In a core box for use in forming turbine blade holding core segments embodying spaced curved blades extending transversely there through and presenting inner and outer free end portions adapted to have inner and outer ring segments cast integrally thereto, a bottom and drag ring construction comprising inner and outer base members disposed in spaced concentric relation, a jig holding ring segment disposed between said base members, a pair of inner and outer jigs disposed in spaced concentric relation on the top portion of said jig holding ring segment, said pair of jigs being shaped to engage longitudinally spaced intermediate edge portions of blades inserted therein to thereby position and firmly hold the bladesin a predetermined angular relation, a pair of inner and outer drag ring segments disposed in spaced concentric relation and coacting with said bottom members to form therewith spaced concentric surfaces shaped to position and retain thereagainst inner and outer series of filler blocks adapted to be assembled between the inner and outer end portions of blades held in said pair of jigs, blades held in said pair of jigsand inner and outer series of filler locks disposed on said positioning and retaining surfaces and between the inner and outer end portions of said blades, removable clamping means superimposed on said series of filler blocks in spaced concentric relation, and a jig ring segment removably secured in spaced concentric relationbetween said clamping means and the upper portions of said drag rings and in engagement with the adjacent edge of each blade at a point intermediate the longitudinally spaced opposite edge portions thereof which are engaged by said pair of jigs. v i

11. In a core box for use informing turbine blade holding core segments embodying spaced curved blades extending transversely therethrough and presenting inner and outer free, end portions adapted to have inner and outer ring segments cast integrally thereto, a bottom and drag ring construction comprising inner and outer base members disposed in spaced concentric relation, a jig holding ring segment disposed between said base members, a pair of inner and outer jigs disposed in spaced concentric relation on the top portion of said jig holding rin segment, said pair of jigs being shaped to engage longitudinally spaced intermediate edge portions of bladesinserted therein to thereby position and firmly hold the blades in a predetermined angular relation, a pair of inner and outer drag ring segments superimposed in spaced concentric relation on portions of thetops of said base members and forming with theexposed portions of the tops of said base members spaced concentric surfaces shaped to position and retain thereagainst inner and outer series of filler blocks adapted to be assembled between the inner and outer end portions of blades held in said pair of jigs, said pair of drag rings being spaced apart a distance commensurate with the length of the blades to be positioned and held in said pair of jigs so as to form with the exposed top portions of said base members and with said jig holding ring segment and jigs a channel in which the blades and filler blocks can be quickly and accurately assembled simply by alternately placing in abutting relation on said concentric positioning and retaining surfaces and in said pair of jigs a pair of inner and outer filler blocks and a blade, respectively, blades held in said pair of jigs and inner and outer series of filler blocks disposed on said positioning and retaining surfaces and between the inner and outer end portions of said blades, removable clamping means superimposed onsaid series of filler blocks in spaced concentric relation, and a jig ring segment removably secured in spaced concentric relation between said clamping means and the upper portions of said drag rings and in engagement with an intermediate portion of the adjacent edge of each of the blades held in said pair of jigs.

12. In a core box for use in forming turbine blade holding core segments embodying spaced curved blades extending transversely therethrough and presenting inner and outer free end portions adapted to have inner and outer ring segments cast integrally thereto, a bottom and drag ring construction comprising inner and outer base members disposed in spaced concentric relation, a jig holding ring segment disposed between said base members, a pair of inner and outer jigs disposed in spaced concentric relation on the top portion of said jig holding ring segment and presenting pairs of downwardly inclined and transversely extending alined notches terminating in undercut portions providing pairs of transversely extending alined grooves adapted to receive snugly therein longitudinally spaced portions of the outlet edge of a curved blade, said pairs of notches being shaped to guide the outlet edge of a curved blade downward into the grooved portions thereof and to-retain the blade inserted therein in a predetermined angular relation, a pair of inner and outer drag ring segments disposed in-spaced concentric relation and coacting with said base members to form therewith spaced concentric surfaces shaped to position and retain thereagainst inner and outer series of filler blocks adapted tobe assembled between the inner and outer end portions of blades inserted and held in said pairs of notches,

blades disposed in each pair of said notches and inner and outer series of filler blocks disposed on said positioning and retaining surfaces and between the'inner and outer end portions of said blades, removable clamping means superimposed on said series of filler blocks in spaced concentric relation, and a jig ring segment removably secured in spaced concentric relation between said clamping means and the upper portions of said therethrough and presenting inner and outer free end portions adapted to have inner and outer ring segments cast integrally thereto, a bottom"v and drag ring construction comprising inner and outer base members secured in spaced concentric relation, a jig holding ring segment disposed in and substantially closing the space between said base members, a pair of inner and outer blade holding jigs removably secured in spaced concentric relation on the top portion of said jig holding ring segment and presenting pairs of downwardly inclined and transversely extending notches terminating in undercut portions providing pairs of transversely extending alined grooves adapted to receive snugly therein longitudinally spaced portions of the outlet edge of a curved blade, said pairs of notches being shaped to guide the outer edge of a curved blade downward into the grooved portions thereof and to retain the blade inserted therein in a predetermined angular relation, said base members having portions of the tops thereof shaped to concentrically position and support thereon a pair of inner and outer drag ring segments, 9. pair of inner and outer drag ring segments superimposed on said portions of the tops of said base members and forming with the exposed portions thereof concentric surfaces shaped to position and retain thereagainst inner and outer series of filler blocks adapted to be disposed between the free inner and outer end portions of blades disposed in said pairs of notches, blades disposed in each pair of said notches and inner and outer series of filler blocks disposed on said positioning and supporting surfaces and between the inner and outer end portions of said blades, removable clamping means superimposed on said filler blocks, and a removable jig ring segment disposed in spaced concentric relation between said clamping means and the upper portion of said drag rings andengaging the inlet edge of each blade at a point intermediate the longitudinally spaced outlet edge portions thereof which are disposed in a pair of said notches.

14. In a core box for use in forming turbine blade holding core segments embodying angularly spaced curved blades extending, transversely therethrough and presenting inner and outer free end portions adapted to have inner and outer ring segments cast integrally thereto, a bottom construction comprising inner and outer base members positioned in spaced concentric relation, a jig holding ring segment disposed between and substantially closing the space between said base members, a pair of inner and outer blade holding jigs secured in spaced concentric relation on the top portion of said jig holding ring segment and presenting pairs of downwardly inclined and transversely extending notches terminating in undercut portions providing transversely extending alined grooves adapted to receive snugly therein longitudinally spaced portions of the outlet edge of a curved blade, said pairs of notches being shaped to guide the outlet edge of a curved blade downward into the grooved portions thereof and to retain the blade inserted therein in a predetermined angular relation, said jigs being removably secured to said jig holding ring segment, and said jig holding ring segment being removably supported between said bottom members so that when the core box has been partially rammed and inverted, said bottom members can be removed from said jig holding ring segment, said jig holding ring segment can then be removed from said pair of jigs, and said pair of jigs can then be removed from the outlet edges of the blades inserted in said pairs of notches.

15, In a core box for use in forming turbine blade holding 'core segments embodyingangularly spaced curved blades extending transversely therethrough and presenting inner and outer free end portions adapted to have inner and outer ring segments cast integrally thereto, a bottom construction comprising inner and outer base members disposed in spaced concentric relation, a jig holding ring segment disposed between said base members, a pair of inner and outer blade holding jigs disposed in spaced concentric relation on the top portion of said jig holding ring segment and presenting pairs of downwardly inclined and transversely extending alined notches terminating in undercut portions providing transversely extending grooves adapted to receive snugly therein longitudinally spaced portions of the ou let edge of a curved blade, said pairs of notches being shaped to guide the outlet edge of a curved blade downward into the grooved portions thereof and to retain the blade inserted therein in a predetermined angular relation, said jig holding ring being removable from said pair of jigs when the core box is inverted, and said pair of jigs being then removable from the outlet edges of the blades inserted in said pairs of notches.

16. In a core box for use in forming turbine blade holding core segments embodying angularly spaced curved blades extending transversely therethrough and presenting inner and outer free end portions adapted to have inner and outer ring segments cast integrally thereto, a bottom construction comprising a base ring segment and a pair of inner and outer blade holding jigs disposed in spaced concentric relation on the top portion of said base ring segment and presenting upwardly facing pairs of downwardly inclined and transversely extending alined notches terminating in undercut portions providing transversely extending grooves adapted to receive snugly therein longitudinally spaced portions of the outlet edge of a curved blade, said pairs of notches being shaped to guide the outlet edge of a curved blade downward into the grooved portions thereof and to retain the blade inserted therein in a predetermined angular relation.

17. In a method of forming turbine blade holding core segments embodying spaced curved blades extending transversely therethrough and presenting inner and outer free end portions adapted to have inner and outer ring segments cast integrally thereto, the steps comprising forming a core box having a bottom portion including inner and outer filler block positioning and retaining surfaces disposed in spaced concentric relation with respect to each other and with respect to the sides of said box and including a pair of blade positioning and holding jigs disposed between and in spaced concentric relation with respect to said inner and outer surfaces and in spaced concentric relation with respect to each other, alternately placing a pair of inner and outer filler blocks on said inner and outer surfaces and a blade in said pair of jigs with the inner and end portion of each blade abutting the proximate portions of said pair of filler blocks to thereby form a series of angularly spaced blades having the inner and outer end portions of each blade disposed between and enclosed by adjacent pairs of said filler blocks, clamping said filler blocks and blades in said box, ramming said box with a coreforming material to a depth sufficient to cover said blades, removing said clamping means and placing a metallic ring segment arbor on said core forming material and in spaced concentric relation with respect to the sides of said box, completing the ramming of said, box with core forming material, inverting said box and removing said bottom: portion, placing cope ring segments in spaced concentric relation on the top portions'of the sides of the inverted box and ramming suificient core forming material between said cope segments to cover the adjacent edges of the blades, placing a metallic ring segment arbor on said core forming material and in spaced concentric relation with respect to the sides of'said cope segments, completing the ramming of the space between said copev segments with the core forming material, removing the remaining portions of the box from the core formed therein, and removably securing a tie rod between the free exposed end portions of each arbor.

18. In a method of forming turbine blade holding core segments embodying spaced curved blades extending transversely therethrough and presenting innerv and outer free end portions adapted to have inner and outer ring segments cast integrally thereto, the steps comprising forming, acore box having a bottom portion including inner and outer filler block positioning and retaining surfaces disposed in spaced concentric relation with respect to each other and with respect to the sides of said box and including a pair of blade positioning and holding jigs disposed between and in spaced concentric relation with respect to said inner and outer surfaces and in spaced concentric relation with respect to each other, alternately placing a pair of inner and outer filler blocks on said inner and outer surfaces and a blade in said pair of jigs with the inner and outer end portion of each blade abutting the proximate portions of said pair of filler blocks to thereby form a series of angularly spaced blades having the inner and outer end portions'of each blade disposed between and enclosed by adjacent pairs of said filler blocks, clamping said filler blocks and blades in said box, ramming said box with a core forming material to a dep h sufficient to cover said blades, removing said clamping means and placing a metallic ring segment arbor on said Y completing the ramming of said box with core forming material, inverting said box and removing said bottom portion, placing cope ring segments in spaced concentric relation on the top portions of the sides of the inverted box and ramming sufiicient core forming material between said cope segments to cover he adjacent edges of the blades, placing a metallic ring segment arbor on said core forming material and in spaced concentric relation with respect to the sides of said cope segments, and completing the ramming of the space between said cope segments with the core forming material.

.19. In a method of forming turbine blade holding core segments embodying spaced curved blades extending transversely therethrough and presenting inner and outer free end portions adapted to have inner and outer ring segments cast integrally thereto, the steps comprising forming a core box having bottom portion including inner and outer filler block positioning and retaining surfaces disposed in spaced concentric relation with respect to each other and with respect to the sides of said box and including a pair of blade positioning and holding jigs disposed between and in spaced concentric relation with respect to said inner and outer surfaces'and in spaced concentric relation with respect to each other, alternately placing a pair 20. In a core for use in forming turbine blade 1 holding core segments embodying a series of spaced blades extending transversely therethrough and presenting inne and outer free end portions adapted to have inner and outer ring segments cast integrally thereto, a core reinforcing construction comprising a pair of metallic ring segment arbors extending throughout the length of the core on either side of and in close proximity with respect to the inlet and on let edges of the spaced blades extending transversely therethrough and terminating in exposed Iree end portions, and a tie rod connecting the free end portions of each arbor.

21. In a core box for use in forming blade holding core segments embodying spaced blades extending transversely therethrough and presenting inner and outer free end portions adapted to have inner and outer ring segments cast integrally thereto, a bottom cons ruction comprising a base ring segment presenting inner and outer concentric drag segment positionin and supporting surfaces and inner and outer concentric fiiler block positioning and supporting surfaces disposedbetween and in proximity to said inner and outer ring segment surfaces respectively, and. a pair of blade positioning and holding jig segments disposed on said base ring segment in spaced concentric relation between said filler block positioning and supporting surfaces.

22. In a core box for use in forming blade holding core segments embodying spaced blades extending transversely therethrough and presenting inner and outer free end portions adapted to have inner and outer ring segments cast integrally thereto, a bottom construction comprising a base ring segment presenting inner and outer concentric drag ring segment positioning and supporting surfaces and inner and outer concentric filler block positioning and supporting surfaces disposed between and in proximity to said inner and outer drag ring segment surfaces respectively, and a pair of biade positioning and holding jig segments disposed on said base ring segment between said filler block positioning and supporting surfaces in spaced concentric relation with respect to each other and with respect to said filler block positioning and supporting surfaces.

23. In a core box for main forming blade holding core segments embodying spaced blades extending transverseiy therethrough and presenting inner and outer free end portions adapted to have inner and outer ring segments cast integrally thereto, a botto a construction comprising a base ring segment presenting inner and outer concentric drag ring segment supporting surfaces cmbodying drag ring segment positioning means thereon and presenting between and in proximity to said inner and outer drag ring segment surand outer concentric drag ring segment positioning and supporting surfaces and inner and outer concentric filler block positioning and supporting surfaces disposed between and in proximity to said inner and outer drag ring segment surfaces respectively, and a pair of blade positioning and holding jig segments disposed on said base ring segment in spaced concentric reiation between said filler block positioning and supporting surfaces and presen 'ng pairs of alined upwardly opening notches arranged to engage longitudinaliy spaced edge portions of blades inserted therein intermediate the free end portions thereof.

25. In a core box for use in forming blade holding core segments embodying spaced blades X-' tending transversely therethrough and presenting inner and outer free end portions adapted to have inner and outer ring segments cast integrally thereto, a base ring segment presenting inner and outer concentric drag ring segment positioning and supporting surfaces and inner and outer concentric filler block positioning and supporting 7 surfaces disposed between and in proximity to said inner and outer drag ring segment surfaces respectively, a pair of blade positioning and holding jig segments disposed on said base ring segment in spaced concentric relation between said filler block positioning and supporting surfaces and presenting pairs of alined upwardly opening notches arranged to engage longitudinally spaced edge portions of blades inserted therein intermediate the free end portions thereof, a pair of inner and outer drag ring segments mounted on said inner and outer drag ring supporting surfaces, respectively, and blades mounted in said jig segments with their ends abutting the opposed inner side surfaces of said drag ring segments.

26. In a core box for use in forming blade holding core segments embodying spaced blades eX- tending transversely therethrough and presenting inner and outer free end portions adapted to have inner and outer ring segments cast integrally thereto, a base segment embodying a pair of concentric blade positioning and holding jig segments presenting pairs of alined upwardly opening notches arranged to engage longitudinally spaced edge portions of blades inserted therein intermediate the free end portions thereof, a pair of inner and outer drag ring segments coacting with said base segment to form a channel adapted to have blades positioned transversely therein by inserting an intermediate edge portion of each blade in a pair of said notches, bladespositioned in said pairs of notches, and a superposed jig carrying ring segment engaging the opposite edge portion of each blade at a point intermediate the longitudinally spaced edge portions thereof which are disposed in a pair of said notches.

ALBERT F. PFEIFFER.

Images