US2859510A - Method of forming a boiler head or the like - Google Patents

Description

Nov. 11, 1958 J. F. BAXA 2,859,510

METHOD OF FORMING A BOILER HEAD OR THE LIKE Original Filed Jan. 13, 1955 5 Sheets-Sheet 1 Q Q oo Z N (D INVENTORY JAMES F. BAXA as ATTORNEY Nov. 11, 1958 J. F. BAXA 2,859,510

METHOD OF FORMING A BOILER HEAD OR THE LIKE Original Filed Jan. 13 1955 5 Sheets-Sheet 2 INVENTOR JAMES F. BAXA 24 mg, QLQ/ HIS ATTORNEYS Nov. 11, 1958 ,J. F; BAXA 2,859,510

METHOD OF FORMING A BOILER HEAD OR THE LIKE Original Filed Jan. 15, 1955 5 Sheets-Sheet 5 Fls.6g

Fi e. 5

INVENTOR JAMES F. BAXA HIS A TTORNEYS United state METHOD or FonMrNn A BOILER HEAD on THE LHQE Griginal application January 13,1955 Serial No. 481,616. giguzlgg and this application July 15, 1955, Serial No.

4 Claims. (Cl. 29-1514) This invention relates to a method of forming a boiler head or the like. This application is a division of my copending application Serial No. 481,616, filed January 13, 1955, abandoned since filing of this application.

The invention has to do with the forming of articles such as boiler heads having an opening therethrough and a tubular projection integral with the article coaxial with the opening for receiving closure means. The closure means may be a threaded plug and the tubular projection may be threaded to receive the plug. For purposes of explanation and illustration the invention will be described as embodied in a boiler head and as practiced in the forming of a boiler head.

The tubular projection may be subjected to heavy stress, especially when the boiler of which the head is a part contains fluid under pressure. It has heretofore been recognized that the wall thickness of the tubular projection should be as great as the specified wall thickness of the boiler head surrounding the tubular projection. To obtain that result separate spuds have been utilized but the cost incident to the provision and attachment of separate spuds is substantial. To avoid that cost it has been proposed to form the tubular projection integral with the material of the head. This has been done by both hot and cold forming but the result prior to the present invention has been a tubular projection of less wall thickness than the head at at least a substantial portion of the tubular projection. Since the wall thickness of the tubular projection should be as great as the wall thickness of the head itself which is required to withstand the pressure within the boiler those skilled in the art have been utilizing metal of unnecessarily great thickness for the heads of boilers in order to form integral tubular projections having the necessary wall thickness to withstand the imposed stresses. This has entailed undesirable expense through the utilization of heads which are heavier than required not only in the cost of the material of the head but also in increased shipping charges because of the increased Weight of the boiler.

I have solved the problem by producing a boiler head or the like having a tubular projection integral with the metal of the head and whose wall thickness is at least as great as the thickness of the material of the head. Specifically, I provide a boiler head or the like comprising a plate-like metal member having an opening therethrough and a tubular projection integral with the platelike metal member and projecting generally normal thereto, the inner surface of the tubular projection being continuous with the periphery of the opening, the thickness of the metal forming the tubular projection being at least as great as the thickness of the metal of the platelike metal member surrounding the tubular projection. Desirably the tubular projection gradually increases in transverse dimension from one end to the other thereof to adapt it to receive a tapered plug. Normally the tubular projection is threaded. If it is to receive a tapered externally threaded closure plug the tubular projection should be of greater transverse dimension at its outer atent ice extremity than at its inner extremity and should be internally threaded to receive the tapered plug. If the tubular projection is to receive an internally threaded closure cap it should be externally threaded. The most common type of closure is a tapered externally threaded closure plug so that normally the tubular projection will be shaped to receive such a plug and internally threaded. The tubular projection may project in either direction from the boiler head.

I preferably form a boiler head or the like by hot die-forming a plate-like metal member having an opening therethrough to enlarge the opening and form a tubular projection integral with the plate-like metal member and projecting generally normal thereto whose inner surface is continuous with the periphery of the opening but with the thickness of the metal forming the tubular projection being at least a portion of the tubular projection less than the thickness of the metal of the plate-like metal member surrounding the tubular projection and upsetting the metal of the tubular projection to increase the thickness of the metal thereof at said portion thereof to a thickness at least as great as the thickness of the metal of the plate-like metal member surrounding the tubular projection. I preferably shape the tubular projection so that it gradually increases in transverse dimension from one end to the other thereof, and I preferably thread the tubular projection. Other details, objects and advantages of the invention will become apparent as the following description of a present preferred method of practicing the same proceeds.

In the accompanying drawings I have illustrated a present preferred method of practicing the invention in which Figure 1 is a cross-sectional view through apparatus for forming a boiler head and illustrating the first step of my improved method;

Figures 2, 3 and 4-are views similar to Figure 1, illus-, trating succeeding steps of my improved method;

Figures 5 and 6 are cross-sectional views through ap paratus for shaping the tubular projection so that it grad ually increases in transverse dimension from one end to the other thereof; and

Figure 7 is a fragmentary cross-sectional view through a finished boiler head.

My boiler head or the like may be of conventional shape and adapted to be applied to a boiler shell in conventional manner but it may be made out of metal of v thinner gauge than has heretofore been required for the manufacture of boiler heads with integral tubular projections to meet particular specifications because the tubular projection which I form integral with the head has at least as great wall thickness at the head. Indeed, I may form a tubular projection integral with a boiler head or the like having even greater wall thickness than the head or the like if for any reason such a structure should be desired.

Figures 1 to 4, inclusive, show one form or my.ap-. paratus for forming a boiler head or the like and illus trate my method. The apparatus comprises a base member 2 which is mounted in fixed position. The base member 2 carries an upsetting die 3 which is upwardly open and of annular shape as shown. The upsetting die is carried by the base member in fixed position.

A plurality of bores 4 are drilled through the base member 2, only one such bore being shown in the drawing for simplicity of illustration. surround the upsetting die 3 and are uniformly spaced. Projecting upwardly through each of the bores 4 is a pin 5 which is resiliently forced upwardly, as, for example, by fluid under pressure. The lower extremity of each pin 5 may carry a piston (not shown) operating in a fluid pressure cylinder. When fluid under pressure is employed The bores 44 preferably I prefer to employ air as the fluid under pressure but hydraulic fluid may be employed if desired.

The pins 5 resiliently support a die member 6 having extending therethrough a die cavity 7 snugly receiving the upsetting die 3 as shown. The die member 6 is adapted to move axially of the upsetting die 3 against the fluid pressure exerted against the pins 5 as will presently be described and may be guided in such movement by the upsetting die 3 alone, or other guide means for insuring properly guided movement of the die member 6 relatively to the base member 2 may be provided. Means not shown limit the upward movement of the die memher 6, that member being shown in its extreme upper position in Figures 1 and 2, being maintained in that position by the pins 5.

A blank 8 is adapted to be supported upon the die member 6. The blank 8 may be a boiler head or the like on which an integral tubular projection is to be formed. The blank 8 may have a wall thickness no greater than the wall thickness required by the boiler specifications. It is predrilled to form therethrough an opening 9. The blank 8 is preheated to the proper temperature for hot forging the particular metal being employed, which may, for example, be a grade of carbon steel appropriate for forming boiler heads.

The blank 8 is maintained in position upon the die member 6 with the opening 9 coaxial with the die cavity 7 by a holding member 10. The holding member 10 has therein an opening 11 of somewhat smaller transverse dimension than the die cavity 7 coaxial with the die cavity 7. The die cavity 7, the openings 9 and,11 and the upsetting die 3, as well as the punch presently to be described, may be of circular cross section although they may also be of other cross section so long as they are designed to conform with one another. In the present illustration they will be assumed to be of circular cross section.

I provide a punch designated generally by reference numeral 12 comprising a holder portion 13 and a punch member 14. The punch member 14 is adapted to pass through the opening 11 in the holding member 10 and has a pointed nose 15. The punch member 14 is coaxial with the die cavity 7. A series of compression coil springs indicated diagrammatically at 16 are disposed about the punch member 14 for biasing the punch relatively to the holding member 10.

At the beginning of a cycle of operations of the die mechanism shown in Figures 14 the punch and holding member 10 are retracted upwardly away from the die member 6. The blank 8 is brought to the required heat and placed upon the die member 6 as shown in Figure l with the opening 9 coaxial with the die cavity 7. The holding member 10 is then brought into operative position to hold the blank 8 against the die member 6 as shown in Figure l. The holding member 10 is pressed against the blank 8 by the springs 16 and may be guided in its movements toward and from the die member 6 by guide means not shown but of a type known to those skilled in the art. The punch holder 13 may be similarly guided.

With the blank 8 held firmly in place against the die member 6 by the holding member 10 the punch is moved downwardly successively to the positions of Figures 2 and 3. The tapered nose 15 of the punch member 14 enters the opening 9 of the blank and enlarges that opening and the punch hot die-forms the metal of the blank '8 at the periphery of the opening which projects radially inwardly of the periphery of the die cavity 7 as shown in Figures 2 and 3. It is inevitable that in such die-forming of the metal its wall thickness will be reduced. This is illustrated in the drawings.

When the punch 12 has reached the position shown in Figure 3 the springs 16 are fully compressed and the portion 13 of the punch directly engages the holding member 10 and has started to move the holding member 10, the blank 8 and die member 6 downwardly up to a point just before the position of the parts shown in Figure 3, the fluid pressure acting upwardly against the pins 5 has been sufiicient to hold the die member 6 in the position shown in Figures 1 and 2. As the punch moves downwardly it carries with it the holding member 10, the blank 8 and the die member 6. Since the upsetting die 3 is fixedly mounted in the fixed base member 2 the downward movement of the punch, holding member, blank and die member causes the annular upsetting die to upset the material of the tubular projection formed on the blank between the punch member and the wall of the die cavity as shown in Figure 4.

' Thus I can form a tubular projection integral with a boiler head or the like having at least as great wall thickneSs as the material of the head and even greater wall thickness if desired. 1 eliminate the necessity of either applying a separate spud or employing for the head material of greater wall thickness than required by the boiler specifications.

It would be possible to utilize the tubular projection formed as above described and as shown in Figure 4 for holding a closure member in place to seal the boiler head, as, for example, by internally threading the tubular projection and screwing an externally threaded closure plug thereinto. However, it is preferred, and customary in the art, to taper the tubular projection and internally thread it so that it is adapted to receive a tapered externally threaded closure plug of conventional construction. The tapering operation is shown in Figures 5 and 6. The boiler head which has been hot die-formed as shown in Figures 1-4 and explained above is further formed in tapering dies, the tapering operation being performed either hot or cold.

There is provided a fixed base member 17 in which is mounted a female tapering die 18 whose inner annular face 19 at the upper portion thereof viewing Figures 5 and 6 is tapered downwardly and inwardly as shown. The mouth or upper extremity of the die 18 has substantially the same shape and transverse dimension as the outside of the tubular projection formed in Figures 1-4. The blank 8 after bein hot die-formed as illustrated in Figures 1-4 is transferred to the tapering dies of Figures 5 and 6, with or without a reheating, and is positioned relatively to the die 18 as shown in Figure 5.

Mounted above the die 18 for vertical movement in a guide 20 is an annular holddown member 21 in which operates a male tapering die 22 having a downwardly and inwardly tapered nose 23 as shown.

While the die 22 remains stationary in the position shown in Figure 5 the holddown member 21 moves downwardly and engages the upper surface of the blank 8 and forces it down against the die 18 with the tubular projection entering the die 18 and being forced radially inwardly. Then the die 22 is lowered to the position shown in Figure 6, the tubular projection on the blank 8 being reformed to the shape shown in Figure 6. The wall thickness of the tubular projection remains substantially the same as formed in the operation shown in Figure 4, i. e., at least as great as the wall thickness of the blank 8 or greater if desired.

After the tapering operation of Figures 5 and 6 the tapered tubular projection is internally threaded as shown at 24 in Figure 7. This completes the formation of the boiler head or the like. Not only is the tubular projection of at least as great wall thickness as the head but it is of constant wall thickness and there is no zone of Weakness due to reduced wall thickness in the finished wall such as has characterized previously integrally formed tubular projections which prior to the present invention as above explained necessitated the employment of metal for the head having a wall thickness or gauge greater than that required by the boiler specifications with the consequent disadvantages above pointed out.

The apparatus herein illustrated is claimed in my copending application Serial No. 629,673, filed December 20, 1956, which is a division of this application.

While I have illustrated and described a present preferred method of practicing the invention it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims.

I claim:

1. A method of forming a boiler head or the like comprising fixedly positioning for hot die-forming a platelike metal member having an opening therethrough, while maintaining the plate-like metal member thus fixedly positioned hot die-forming the plate-like metal member to enlarge the opening and form a tubular projection integral with the plate-like metal member and projecting generally normal thereto whose inner surface is continuous with the periphery of the opening but with the thickness of the metal forming the tubular projection being at at least a portion of the tubular projection less than the thickness of the metal of the plate-like metal member surrounding the tubular projection and while continuing to maintain the plate-like metal member thus fixedly positioned upsetting the metal of the tubular projection to increase the thickness of the metal thereof at said portion thereof to a thickness at least as great as the thickness of the mteal of the plate-like metal member surrounding the tubular projection.

2. A method of forming a boiler head or the like comprising fixedly positioning for hot die-forming a platelike metal member having an opening therethrough, while maintaining the plate-like metal member thus fixedly positioned hot die-forming the plate-like metal member to enlarge the opening and form a tubular projection integral with the plate-like metal member and projecting generally normal thereto whose inner surface is continuous with the periphery of the opening but with the thickness of the metal forming the tubular projection being at at least a portion of the tubular projection less than the thickness of the metal of the plate-like metal member surrounding the tubular projection, while continuing to maintain the plate-like metal member thus fixedly positioned upsetting the metal of the tubular projection to increase the thickness of the metal thereof at said portion thereof to a thickness at least as great as the thickness of the metal of the plate-like metal member surrounding the tubular projection and shaping the tubular projection so that it gradually increases in transverse dimension from one end to the other thereof.

3. A method of forming a boiler head or the like comprising fixedly positioning for hot die-forming a plate-like metal member having an opening therethrough, while maintaining the plate-like metal member thus fixedly positioned hot die-forming the plate-like metal member to enlarge the opening and form a tubular projection integral with the plate-like metal member and projecting generally normal thereto whose inner surface is continuous with the periphery of the opening but with the thickness of the metal forming the tubular projection being at at least a portion of the tubular projection less than the thickness of the metal of the plate-like metal member surrounding the tubular projection, while continuing to maintain the plate-like metal member thus fixedly positioned upsetting the metal of the tubular projection to increase the thickness of the metal thereof at said portion thereof to a thickness at least as great as the thickness of the metal of the plate-like metal member surrounding the tubular projection, and threading the tubular projection.

4. A method of forming a boiler head or the like comprising fixedly positioning for hot die-forming a plate-like metal member having an opening therethrough, while maintaining the plate-like metal member thus fixedly positioned hot die-forming the plate-like metal member to enlarge the opening and form a tubular projection integral with the plate-like metal member and projecting generally normal thereto whose inner surface is continuous with the periphery of the opening but with the thickness of the metal forming the tubular projection being at at least a portion of the tubular projection less than the thickness of the metal of the plate-like metal member surrounding the tubular projection, while continuing to maintain the plate-like metal member thus fixedly positioned upsetting the metal of the tubular projection to increase the thickness of the metal thereof at said portion thereof to a thickness at least as great as the thickness of the metal of the plate-like metal member surrounding the tubular projection, shapingthe tubular projection so that it gradually increases in transverse dimension from one end to the other thereof and threading the tubular projection.

References Cited in the file of this patent UNITED STATES PATENTS 1,137,600 Gallagher Apr. 27, 1915 1,246,456 Parpet Nov. 13, 1917 1,264,854 Possons Apr. 30, 1918 1,623,325 Wetmore Apr. 5, 1927 2,078,195 Cornell, Jr Apr. 20, 1937 2,149,508 Coe Mar. 7, 1939 2,157,354 Sherman May 9, 1939 2,168,641 Arbogast Aug. 8, 1939 2,373,901 Lowery Apr. 17, 1945 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,859,510 November 11, 1958 James F. Baxa It is herebjr certified that error appears in the -printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, line 17, for "being at least" read being at at least line 51, for "at", second occurrence, read as line 56, for "form or" read form of column 5, line 26, for "mteal" read metal Signed and sealed this 3rd day of March 1959.

SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Attesting Oflicer Commissioner of Patents

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