US1514335A - Press forging and similar operation - Google Patents

Description

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Nov. 4, 1924. 1,514,335

G. H. PHELPS ET AL PRESS FORGING AND SIMILAR OPERATION Filed Dec. 15. 1921 Patented Nov. 4, 1924.

UNITED. STATES PATENT OFFICE.

GEORGE E. PHELPS, OF WAREHOUSE POINT, CONNECTICUT, AND THOMAS E. MURRAY, JR., OF'BROO'KLYN, NEW YORK; SAID PHELPS ASSIGNOR TO THOMAS E..MURRAY,

OF BROOKLYN, NEW YORK.

PRESS FORGING AND SIMILAR OPERATION.

Application filed December 15, 1921. Serial No. 522,480.

To all whom it may concern:

Be it knownthat we, Gnonon H. PHELPS QIHClTHOMAS E. MURRAY, J12, citizens of the United States, said Pnnnrs residing in Varehouse Point, Connecticut. and said MURRAY residing in Brooklyn, New York, have-invented certain new and useful Improvements in Press Forgings and. Similar Operations, of. which thefollowing is a specification.

The present invention provides a method and apparatus by which metal or metalscan be-worked and shaped'economically and expeditiously to secure products which are now made by press forging, die casting, extruding and similar. operations in which the metal issoftened or meltedand shaped by mea-ns'of molds, dies or the like.

The accompanying drawings illustrate embodiments of the invention.

Fig. 1 illustrates in section theparts in their initial position;

Fig. 2; is a similar section of the finished forging;

F ig. 3 isa plan of a portion thereof;

Fig. t-is a section similar to Fig. 1 illustrating an alternative method;

Fig, 5 is a plan on the line 5-5 of Fig. 4,

Figs. 6 and 7 are sections of other alternatives. I Referringto-Figs. 1, 2 and 3, the forging to bemade isa gear blank 1 of aluminum orvother soft metal with areinforcing disc 2- of steel or other comparatively strong metalembedded in the aluminum.

The metal in the beginning is in the form of rods 3, 4 (Fig. 1) of aluminum with a plate 5 of steel (which in the instance shown is-to-be'unchanged in shape in the final product, but which in other cases may be shaped by the forging Operation). These pieces 3, 4 and 5 are introduced as shown into a tubular mold 6 at the lower end of which is a terminal 7 of copper mounted on asupport 8. The terminal:7 is insulated from the casing 6 and in the upper end of the latter there is a movable terminal 9 bearing on top of the slug 8. The terminals 7 and 9 are at the opposite ends of an electric circuit and when the current is applied it passes through the pieces of metal 3, 5 andallto" soften them; andthe upper terminal 9' is pressed.downward-to forge the mass of metal into the desiredshape. The ends of'the terminals 7 and 9 are shaped to produce the desired configuration on the top and bottom of the forging. A slight menibrane or tin, 1, left in the center may be easily punched out afterwards.

The mold 6 may be of various materials, such, for example, as chilled cast steel. The terminals 7 and 9 may be steel or copper inserts constituting the ends of electrodes. The lower terminal may beheldstationary, being in that case in effect a fixed part of the mold, while the upper one constitutes the plunger, moved downward as indicated by the arrow by. means of any suitable motor. A solenoid designed so as togive any desirable rate of-movement of themetal may, for example, be used as the motor.

In the arrangement shown in Figs. at and 5 the two electrode terminals 10 and 11 are stationary and located at opposite ends of the mold 12 which is insulated from the lower terminal. The metal to be forged is in theform of a cylindrical blank or slug 13 and, when sufficiently heated by the passage of the current; is forged by the clownward movement of a'presser 14 which forms a socket in the top of the blank and presses the metal out at the sides into the annular recess 15. Such a mold would have to be split as shown in Fig. 5 to permit removal of the forging; thetwo, parts being guided in their movement toward and away from each other on guide" rods 16. An annular space 17 or clearance should be left between the sides of the mold and the blank- 13 so that current will pass through the latter and not through the mold itself.

F ig. 6 shows another arrangement for producing the product of Fig. 2, in which the recesses constituting the hole in the center of the product are made by means of plungers 18 and 19" passing through the electrode terminals? and 9. Here we have shown the metal to be forged in blanks of slightly different designfrom those of Fig. 1; a single rod 20 of aluminum extending between the terminals and passing through a ringQl of steel. In operation the plungers will move inward to the desired positions with relation to the terminals, after which the upper terminal-and the plunger 18 will move down together to the final posit-ion.

This arrangement gives better contact surfaces between the blank 20 and theelectrodes and reduces the heatingeflect on the electrodes at their point of contact with the blank.

It is not essential that the mold be a closed one. In Fig. 5, for example, the two halves of the mold 12 may be separated in the beginning and may be brought together to compress the product simultaneously with or immediately after the passing of the current.

In 7 we have shown an arrangement of the same character for producing the product of Fig. 2. The terminals 7 and 9 and the plungers 18 and 19 are the same as in Fig. 6. The sides of the mold, however, are formed byfianges 22 and 23 projecting inward from the heads of the terminals and constituting in fact parts of the same. In this case, as in the described use of the split mold of Fig. 5, the metal to be forged in the beginning is confined between the ter minals constituting parts of the 'mold; but the heating operation is initiated while the metal is actually in the open air, and the mold is not closed until the parts are brought together as described.

In operation a pressure will be put upon the plungers and the electrodes so that as soon as the current is applied the plungers will move inward and the terminal 9 will rangements'of the electrode terminals and pressers may be utilized. in carrying outthe inventlon. r

In a patent of Thomas E. Murray, J12,

' No. 1,281,636, of October 15, 1918, there is described a method of electric welding which consists in subjecting the parts to be united to a current of extremely high ampere strength or current density per square inch, and of very brief duration. We prefer to apply the current in the same way to the present forging operation. For example, we may utilize a current of ninety thousand amperes or more per square inch applied for about a quarter of a second in the case ofsmall forgings. This, however, is not the only method of heating with the electric current within our invention. The shaping of the product by a very quick operation may be accomplished with other methods of application of the current. The quick upsetting of the metal and the necessary pressure for obtaining such a quick operation serve to produce considerable heat in addition to that produced by the passage of electric current.

Preferably also the entire blank is confined withinthe mold and is engaged by the that there is practically no loss of heat by radiation. The greatest advantage of the lnvention lies in the unlformity with WhlCh a number of such operations can be per formed. The current can be controlled as to intensity and duration with great accu racy, and so can the take-up or movement of the presser. Thus we will have a uni form heating over a uniform period of time,

'a uniform speed of operation orflow of the metal and a uniform density of the resultmg forging.

particular molding operation, producing an actual liquefaction or even a vaporization thereof if that should be necessary for fine and intricate forging. The pressure will generally be applied before the closing of the electric circuit so as to take effect as soon as the metal softens andwill, of course, be continued throughout the take-up of the presser. broken before the completion of the take-up so that theactual forging and densifying operations will continue while the metal is cooling from its maximum temperature.

While we have referred to the operation as fpress forging, it may be applied in such a way as to be practically a die casting operation in which liquid metalis forced into a die and cooled therein under pres sure. A suflicient current may be used to liquefy the metal, or even to vaporize it if necessary, so as to permit the forcing of it into the sharpest corners and the mostintricate shapes. Ordinary die casting operations are limited to certain metals which can be maintained at the desired fluidity while being transferred into the die. IVith the present invention metals can be die cast which are not susceptible to such treatment The current will be continued only long enough to bring the metal to the exact degree of plasticity required for the The process presents such wide m Generally the current will be possibilities in the matter of temperature control that it may in fact be applied to operations in which the metal to be worked is partly forged, partly cast and partly extruded to secure a product of the desired shape. The process is applicable also not only to the reshaping of the entire blank but to the reshaping of only one end or other part of the blank, as in the upsetting of a bolt head or a more complicated shape on the end of a rod.

In fact, where the metal is rendered sufiioiently fluid we may, for some products, do without any special pressing mechanism, relying on the weight only of the upper electrode to maintain it in contact with the work during the operation.

An important feature of the invention is its applicability to the making of products composed of two or more metals of different melting points, such as the aluminum and steel product of Figs. 2 and 3. In working with a plurality of metals the temperature may be regulated to such a point as to fuse one of the metals and not the other or others, or even to volatilize one or more of them, or merely to soften them sufficiently for the particular purpose in hand.

\Ve have referred to steel and copper as examples of suitable metals for the terminals but there are various other metals or alloys or compositions having suitable electrical and physical properties to permit their use instead of steel and copper. It is important, though not always essential, that the blank be of less cross-section than the terminal from which it receives its current. Thus the total conductivity of the terminal will be greater than that of the blank and the heating effect on it will be less in the cases illustrated. In the cases illustrated a blank of comparatively small cross-section is used with comparatively large terminals. Consequently, in order to provide sufficient metal to make the product of the full width of the terminals the blank has to take a long shape for such products as are illustrated. For other cases, however, the length, in proportion to the diameter may, of course be less. This means a very considerable working of the metal, which is advantageous. It also allows a long stroke of the machine producing a high pressure on the product at the end of the stroke.

Though we have described with great particularity of detail certain embodiments of our invention yet it is not to be understood therefrom that the invention is restricted to the particular embodiments disclosed. Various modifications thereof may be made by those skilled in the art without departure from the invention as defined in the following claims.

What we claim is 1. In press forging and similar operations using a mold, the method which consists in heating the metal to be forged by the passage of an electric current through a circuit including such metal and a part of the molding surface and pressing the metal into the shape of the mold by means engaging the metal at a point within the mold.

2. In press forging and similar operations, the described method which consists in heating the metal to be forged by subjecting it to a current of extremely high ampere strength and of very brief duration and pressing it into a desired shape while thus heated.

3. In press forging and similar operations the method which consists in heating the metal while in a mold by the passage through it and through a part of the molding surface of an electric current to a sufficient temperature and pressing it into the shape of the mold, the heating and shaping of the metal being effected in a very brief interval of time.

4:. In press forging and similar operations using a mold, the method which consists in heating the metal to be forged by the passage of an electric current through a circuit including such metal and a part of the molding surface, while the metal is entirely confined within the mold.

5. In press forging and similar operation, the method which consists in heating the metal to be forged within a mold by subjecting it to a current of extremely high ampere strength and of very brief duration and pressing it into the shape of the mold while thus heated.

6. An apparatus for press forging and the like, including in combination a mold adapted to enclose the entire body of metal to be forged and means for heating such metal including a terminal constituting part of the molding surface. and means for pres ing the metal into the shape of the mold.

7. An apparatus for press forging and the like, including in combination a mold adapted to enclose the entire body of metal to be forged and means for passing an electric current through such metal including a terminal constituting part of the molding surface, and means for pressing the metal heated by such current into the shape of the mold.

In witness whereof, we have hereunto signed our names.

GEORGE H. PHELPS. THOMAS E. MURRAY, JR.

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