US2169228A - Apparatus for making pressure vessels - Google Patents

Description

Aug. 15, 1939. DEBQOR 2,169,228

APPARATUS FOR MAKING PRESSURE VESSELS Filed Aug. '7, 1937 INVENTOR ROBERT DEBOR %TTORNEY Patented Aug. 15, 1939 UNITED STATES PATENT OFFIQE APPARATUS FOR MAKING PRESSURE VESSELS Application August '7, 1937, Serial No. 157,980 In Germany August 12, 1936 10 Claims.

This invention relates to apparatus for forming hollow bodies provided with constrictions, and more particularly to pressure vessels comprising interconnected hollow spheroids which are formed from cylindrical shells.

In hollow bodies of the aforementioned type, it is important that the walls at the constricted zones be at least as thick, and preferably thicker than the walls of the spheroidal zones. When a tube is deformed to form constricted zones, the necked-down portions ordinarily undergo an undesirable thinning action during the forming operations as a result of the drawing and spreading of the metal. This tendency is overcome in the present invention through the use of pressure forming dies or tools of improved design which operate to cause flow of the metal in the direction of the constrictions during the forming operations.

The principal objects of the present invention are: to provide an improved apparatus for forming hollow spheroids from cylindrical shells; to provide forming-tools of simplified and improved design; to provide apparatus for constricting a cylindrical shell at spaced intervals and simultaneously with the forming process reinforcing the portions by causing a flow of metal to the constricted zones; and to provide a cylindrical forming tool which contacts the shell along a substantially continuous path, as defined by the line of intersection of two intersecting cylinders. These and other objects of the invention will become readily apparent from the following specification and appended drawing disclosing one form of apparatus which may be employed in practicing the invention. In the drawing:

Fig. 1 is an elevational view of an apparatus embodying this invention, showing the left half in section;

Fig. 2 is a cross-sectional view taken on the line 2-2 of Fig. 1, showing a shell in broken lines in position at the start of the forming operation;

Fig. 3 is a cross-sectional view similar to Fig. 2, showing parts in telescoped relation at the end of the forming operation;

Fig. 4 is a horizontal sectional view taken on the line 4-4 of Fig. 1;

Fig. 5 is an elevational view showing the upper forming tools with a completed spheroidal shell shown in its normal position at the end of the operation;

Fig. 6 is a perspective View of a portion of the lower forming die;

Fig. '7 is a longitudinal sectional View of the shell, partially deformed during the initial stages of the forming operation; and

Fig. 8 is a longitudinal sectional View of the finished shell, showing the concentration of metal at the constricted zones.

Referring again to the drawing, the apparatus comprises two blocks ll and I2 which lie opposite one another for mounting within a press or similar machine which is capable of moving one or both of the blocks alternately toward and away from one another. The upper block I l, as shown in Figs. 1 and 5, is provided with a plurality of aligned upper forming tools l3 consisting of base members M which are secured tightly against the block I l, as by means of stud bolts !5, which are locked in position by pins IS. The upper tools terminate at their lower extremity in cylindrical tubes ll, the axes of which coincide with the line of relative movement between the blocks H and i2. The respective tools l3 are aligned in spaced relation separated on centers preferably slightly in excess of the inner diameter of the tubes 51.

Similarly, the lower block [2 is provided with a plurality of lower forming tools [8, each of which is provided with a base member H] which is secured tightly against the lower block I2, as H by means of stud bolts 22. Looking pins 23 maintain the parts in assembled relation. The lower tools comprise cylindrical tubular members 24, each of which is arranged to telescopically receive a corresponding tubular portion ll of the upper tools 13. The respective tubular members I! and 24 are yoked and provided with curved impact edges 25 and 26 which lie flush against the surface of the shell S when in the starting position, as indicated in Figs. 1 and 2. These edges are preferably provided with the faces matching the contour of the outer wall of the cylindrical shell S, so as to provide an appreciable contact surface. Thus, it will be seen that, as the cylin- 4 drical shell S is placed between the upper and lower tools l3 and I8, respectively, the curved edges 25 and 26 lie flush with the outer contour, following a path defined by the line of intersection formed by two intersecting cylinders. This path of contact when projected, for example, upon a plane tangent to the top of the shell, is represented by a circle. During the forming operation, this circular contour, as determined by the shape of the tubular members l l and 24, deforms the shell S into spheroidal zones.

To provide space during the forming operation for the constricted zones, the edges 25 and 26 are provided with diametrically opposed indentations 21 and 28 which accommodate the respective necks 32 located between adjoining spheroids. When the upper and lower tools are in full telescoped position, as indicated in Fig. 3, the indentations 21 and 28 form a circular contour. Inserts 29 having a wall thickness equivalent to the wall thickness of the cylindrical tubes I! are mounted adjacent to the base members l9 and are provided with curved edges 3| conforming with the contour of the edges 25. When the forming operation is complete, the inserts 29 form a continuation of the cylindrical members ll, so as to provide a cavity of uniform inside diameter and to compensate for the difference in the inner diameters of the respective cylindrical members IT and 24.

In operation, an apparatus of the type disclosed in Fig. 1 and provided with one or more cylindrical tubes I1 and 24, as desired, is mounted within means capable of exerting intermittent impact and compressive action between the respective blocks II and I2. A cylindrical blank or shell S is preferably first heated, as in a furnace or by the use of heavy current electrodes attached at opposite ends of the shell, and the shell is then placed between the respective tools l3 and I8, so that it is contacted by the edges 25 and 26. The respective blocks II and I2 are then reciprocated toward and away from one another, as indicated by the double arrow in Fig. 1, the two respective blocks gradually being compressed into closer proximity. During this operation, the shell S is manually or mechanically rotated in any convenient manner either continuously or between respective impact strokes, for example, by means of a clamp 20 and lever 2|, as shown in Fig. 5. Ihe impact action distorts the shell S gradually, so that after the first few strokes it is deformed to the partially completed shape indicated in Fig. 7. The pressure is applied at first against the outside casing of the shell S along a zone extending from the subsequent constriction to the largest diameter of the spheroidal zone. As the action continues, however, and the upper tool telescopes within the lower tool, the contact surfaces of the respective edges 25 and 26 extend slowly toward the constricted zones, imparting an axial component to the pressure, and at the same time concentrating the metal in the wall portion of the shell S in the general direction of the constrictions, so that when the operation is complete, the wall thickness of the necked-down portions is materially increased, as shown in Fig. 8. When the operation is complete, the edges 25 of the cylindrical tubes I! contact the edges 3| of the inserts 29 forming a cavity of continuous inner diameter for receiving the respective spheroidal portions of the shell S. The constricted zones 32 of the shell S then snugly fit within the circular contour formed by the indentations 21 and 28. After the respective blocks have reached the position indicated in Fig. 3, the members are retracted and the shell is either removed, or it is advanced axially for a subsequent operation.

It is to be understood that various modifications of the herein disclosed apparatus may be made without departing from the scope of the invention or sacrificing any of its advantages.

I claim:

1. Apparatus for deforming a cylindrical shell into a series of interconnected hollow spheroids, comprising a cylindrical tube; means for inter mittently urging said tube radially inward against said shell; and means for rotating said shell.

2. Apparatus for deforming a cylindrical shell into spheroidal shape, comprising a cylindrical tube having an inner diameter equal to the outer diameter of said shell; means for intermittently urging said tube radially inward against said shell; and means for rotating said shell.

3. Apparatus for deforming a cylindrical shell into a series of interconnected hollow spheroids, comprising a plurality of aligned cylindrical tubes, said tubes being provided with curved impact edges for engaging the wall of said shell; means for intermittently pressing said tubes axially inward against said shell; and means for rotating said shell.

4. Apparatus as claimed in claim 3 wherein the inner diameter of at least one of said tubes corresponds to the outer diameter of said shell.

5. Apparatus for forming hollow spheroids from a cylindrical metal shell comprising a pair of opposed telescoping cylindrical tubes, said tubes being yoked to receive said shell; means for rotating said shell; and means for providing impact pressure to telescope said tubes.

6. Apparatus as claimed in claim 5 wherein the yoked portions of said tubes have curved edges lying flush against the surface of said shell.

7. Apparatus as claimed in claim 5 wherein the yoked portions of said tubes are provided with aligned indentations to form and receive the constricted portions of said shell lying between ad- J'acent spheroids.

8. In an apparatus for forming hollow interconnected spheroids from a cylindrical metal shell comprising at least one pair of telescoping tubes, said tubes being yoked to receive said cylindrical shell, the inner diameter of the smaller telescoping tube corresponding with the outer diaameter of said shell; and an insert secured within the larger of the telescoping tubes and having a wall thickness equal to the Wall thickness of the smaller telescoping tube and abutting the edges of the yoked portions when the tubes are in fully telescoped position, whereby a chamber of uniform diameter corresponding to the diameter of said shell is formed.

9. Apparatus for deforming a cylindrical shell into spheroidal shape comprising, a pair of telescoping tubular tools projecting against opposite sides of said shell, said tools being provided with curved impact edges for engaging the periphery of said shell; means for pressing said tools intermittently against said shell to telescope said tools and deform said shell; and means operative between the periods of applied pressure to provide relative rotative motion between said shell and said tools.

10. Apparatus as claimed in claim 9 wherein the curved edges of said tools are provided with diametrically opposed substantially semi-circular indentations, said indentations forming when said tools are in fully telescoped position oppositely disposed circular openings accommodating constricted zones of said shell.

ROBERT DEBOR.

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