US1496362A - Method of producing metal rims - Google Patents

Description

7 June 3 1924. 1,496,362

K. B6HLE METHOD OF PRODUCING METAL RIMS v filed March a. 1921 t) f 'i 4.. xx F i;..E5. 3 v *1 H5 m 2 III I /94 Fig 2 LS 5 A B Patented June 3, 192

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KARL BI-ILE, O3? ESSEH, GERJVIANY, ASSIGNOIL TQ KRUPP AKTIENGESELL- SCI-IA'ET, F ESSEN-ON-THE-RUHR, GERMANY.

METHOD OF PRODUCING METAL RIMS.

To all whom it may concern:

Be it known that I, KARL BoHLn, residing at Essen, Germany, a citizen of the German Republic, have invented a certain new and 5 useful Improvement in Methods of Produo ing Metal Rims, of which the following is a specification. My invention relates to a method ofproducing solid drawn cylindrical rims from flat metal rings which will render it possible to manufacture rims of the type specified on a drawing press in the course of a single working operation.

In the drawing atlixed to this specification and forming part thereof, the manner of carrying my invention into practical effect is illustrated in a purely diagrammatic manner by way of example. In the drawing v Fig. l is a sectional View of the metal ring destined for the production of a rim, Fig. 2 is a similar view of the rim when ready made,

Figs. 3 and 1 are axial sections through a drawing press and the workpiece showing the results of the pressing operations where both workpiece and drawing press have been.

dimensioned on other lines than those laid down by myinvention, 1

Figs. 5 to 7 are similar views showing the results of the pressing operation carried outin accordancewith my invention.

A- seamless cylindrical rim B (Fig. 2) may be produced out of a flatmetal ring A (Fig. 1) on the drawing press, provided the possibility be givenby a suitable cooperation of the stamp and die of the press-of each section of ring A being turned or twisted by 90 relatively to its initial position. To this end a press is required, the stamp of which is fitted with a cylindrical part,

corresponding to the inside diameter of the rim, and a conical member located in front of said cylindrical part.

However, as experiments have shown it will prove impossible to produce the rim on such a press whenever the metal ring and the press itself are dimensioned along lines which are not in accordance with my invention, as will be understood from the following explanations with due reference to Figs. 3 and 4.

On the stamp C (Fig. 3) being lowered, the conical section c -of said stamp first of all enters the opening of the metal ring A,

Application filed March 3, 1921. Serial No. 449,559.

alterations of this description the workpiece offers definite resistance, in addition to which there come to arise between the workpiece and the conical member 0 of the stamp, on the one hand, and between the .vorkpiece and the die, on the other hand certain frictional forces which oppose the lowering of the stamp. Now whenever the force transmitted by the stamp to the workpiece, and which strives to draw the workpiece down into the die, prove to be greater than the resistance, which the workpiece opposes to being thus drawn down, then, as disclosed in Fig. 3, the workpiece A will come to cleave to the conical section 0 of the stamp and will be drawn through the die D without any material alteration of its cross section. Again, wherethe conditions happen to be reversed, and where the resistance offered by the workpiece against being drawn down into the die is the more powerful, the workpiece A will not be even completely drawn down into the die but will, as Fig. 4 discloses, obtain a cylindrical shape only at one portion of its circumference. From the foregoing explanations it will be understood that the production of cylindrical rims from fiat metal rings can only be successfully accomplished provided the force brought to act upon the workpiece, by the stamp, and which tends to draw the workpiece down into the die, will always and up to the moment when the conical section of the stamp passes out of the workpiece be approximately so big that it will come to be counterbalanced by the resistance to be overcome when drawing the workpiece through the die.

It is on an appreciation of these facts that the improved method is based. For experience has demonstrated that the conditions above set forth can only be created on the inside and outside diameters of the workpiece employed being disposed in a certain definite relation to the diameter of the bore of the die. If, for example, D (in Fig. 1) denote the outside diameter of the workpiece, 'h the width of the ring, and d (Fig. 3) the diameter of the bore of the die, then, whenever it is a question of producing iron rims, the value of D must be disposed wlthin the hnnts created by the formulae.

lvloreover, the trigonometrical tangent of the angle of inclination pertaining to the shell lines of the conical portion of the stamp relatively to its base, will obtain a value from 6 to 7, corresponding to angles of inclination of from about 80 to 83F.

In the improved drawing press disclosed in Figs. 5 to 7 and destined to practically realize the above-described novel'method, E

denotes the stamp, e the cylindrical and e the conical part thereof. The die F is provided with an annular opening f Serving for the accommodation of the ring shaped 2 workpiece A. The diameter of the opening the stamp E being lowered, the conical part c thereof enters the opening left in the workpiece A and enlarges it. At the same time, by the cooperation of the die F the outside diameter of the workpiece is reduced so that each section thereof will come to be turned Within its plane, and the workpiece will thus obtain a substantially conical shape (Fig. 6). As soon as the stamp has entered so deep down into the workpiece that the conical section c thereof will just come to pass out of the opposite end of the workpiece, this latter, which is still retained at its rearward end by the upper edge of the die, has already obtained a substantially cylindrical shape. During the entire portion of the pressing operation just described, the force imparted by the stamp to the Workpiece, and which tends to pull the workpiece down into the die, still remains approximately so big that it will come to be counterbalanced by the resistance which would have to be overcome when drawing the workpiece through the die, so that neither the case illustrated in either Figs. 8 or 4 is liable to arise. Toward the end of the motion executed by the stamp E, its collar 6 comes to bear up against the workpiece and forces it completely down into the die F (Fig. 7). As soon as the stamp has carried out its return motion, the rim thus completely pressed in the course of a single working operation is removed from the die by the ejector G.

Claim:

The method of producing solid drawn cylindrical rims out of flat circular metal rings by the use of a drawing press having an annular female die and a stamp adapted to enter said annular die which consists in placing the fiat metal ring upon the die of the drawing press and causing the stamp of the drawing press which is provided with a cylindrical part corresponding in width to the inside diameter of the rim and a conical tapered part arranged in front thereof, to engage said flat metal ring to draw said ring into said die, the ring having equal thickness and the width and outside diameter of the ring relatively to the diameter of the bore of the die being so dimensioned that the ring is transformed to a finished cylindrical rim by only one stroke of the stamp.

The foregoing specification signed at Essen, Germany, this 19th day of January,

KARL BOHLE.

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