US1764633A - Method of manufacturing dies - Google Patents

Description

June 17, 1930. LQKELLER l 1,764,633;

METHOD OF MANUFACTURING DIES Filed May 22 1925 I mre/2/0/ Freda/70H. lflq/ef omTEDfsTATEs Patented June 1 7,

PATENT oFFicEfi;

FREDERICK tAwREN'c KELLER, or CHICAGO, ILLINOIS, AssrGNoRi "11o WESTERN EnEcrRrccoiiiranv, ,IivooRroRAr noE NEW YoRK, 1a. Y., A coREo ATIoN E "nEw YOR Application filed. May 22,,

This invention'relates to methods of manufacturing dies, and more particularly to methods of manufacturing blanking dies.

An object'of the invention is to simplify and improve the construction of dies and the'rebyreduce theamount of labor involved in the finishing of the openings in such dies.

The invention contemplates the swaging of the material of which a die is 'made, around a mandrel and then withdrawing the mandrel to leavean opening corresponding to theshape of the mandrel. In accordance with one embodiment of theinvention, the opening in the blanking die is made somewhat larger than required and the opening is then reduced to the proper size by subjecting the die to a high pressure causing a cold flow of the metal around themandrel which is of the size required for the opening.

It is believed that a better understanding of the invention may be had by reference to the following description taken in conjunction with the accompanying drawing showing an apparatus by means of which the invention may be practiced, and in which Fig. 1 is a fragmentary plan view of a die and mandrel associated with a yoke as 7 they appear in the initial stage of the swagtelephone and other apparatus.

ing process;

Fig. 2 is a fragmentary sectional view taken on the line 22 of Fig. 1 showing in addition portions of the ram and bed of a hydraulic press in position to press the die into the tapered bore of the yoke, and

Fig. 3 is a reduced plan view of the yoke anddie. 7

Referring to the drawing in which similar reference characters represent the same parts in the various views, the numeral 6 designates a die member of the typeused 1n punch presses for blanking variously shaped fiat pieces such as are used extensively in The die member illustrated is designed for punching blanks for forming contact springs having the shape ofthe opening in the die.

In order that a punch pressin which such 1 dies are used may operate properly it is necessary that the outline of the opening in the die element conform precisely to the out- 5 "METHOD oE AnUEno'ru nvenIEs 192s; seriai No. 110,847."

line of the punch. -Heretofore it has been the practice in some cases to file theo'pening to its fin'al size manually, involving a great amountof accurate and skilled labor since these parts are usually made of hard metals such as carbontool steel. j

According tothe present invention, an opening 11 is made in the die member slightly larger than a mandrel 12' which consists of a rectangular base 4 and a shank5 of hardened carbon tool steel. Nospecial attention is paid to thesizeor the exactness of the outline ofth'e opening in the die except that'it be larger than themandrel. The ideal condition is an opening ranging from 1/200 inch to 1/64: inch larger. than'the arbor. The opening is then reduced to the proper size by subjecting the dieto a high lateral pressure which is produced by forcing the die downa tapered opening 9=of a yoke 7 of hardened carbon tool steel. The yoke has a grip- 20, to facilitate handling it and a bandf17 of sheet metal is-provided-aboutthe exterior of the yoke to preventthe yoke fromscatteringif it should burst due to the high pressure. The die member 6 isturned about 7 its outer periphery, with a; beveled; edge having a 3 degree angle whichcorresponds with the slope of thefrusto-conical opening 9 of the 'yoke, and its size-is such that its greatest diameter'is equal to thegreatest diameter of the opening in 'theyoke, therefore,- whenthe die is placed in the yoke,'its top surface will lie flush face of theyoke.

' The upper part the die has a reduced portion 15 since it hasbeenfound that when the dieblank is'made as a regular. frustum there is a tendency'for it to buckle and'become distorted due'to thefact that there is a contraction along the diameter. 1 Whenthe upper portion of the die is reducedas shown,

this tendency is greatly minimized, since the spacethus provided affords a place for the. 'metal to flow. i Y

When the die is placed in] the yoke a spiral compression spring 14 holds the mandrel in position and as the die is forced down into theyoke by a ram 16 of hydraulic withthe top surice the arbor.

As an example in the process of producing a carbon tool steel die 5 inches m diameter, a yoke .7 of hardened carbontool steel is placed upon a bed 18 of a hydraulic press.

A coating of White lead and oil is applied to 'the' inclined surface of the yoke and to the beveled edge of the die and a similar coating is applied to the mandrel and the Walls of the opening in the'die. 'The'man drel is then inserted in the die opening and the die is positioned in the yoke'and pressed down the tapered bore of the yoke about two inches under a pressure-of approximately sixty-five tons. During this operation the thickness of-the'die increases about 11/ 16 inch and the metal of the die is forced around the mandrelgiving the required shape and size to the opening. After the pressure is removed, the die is forced out of the yoke by any suitable means and the mandrel is removed completing the die.

It will be understood that the embodiment ofthe invention herein described and illustrated' is merely a useful and convenient form of the invention, which is capable of many other modifications Without departing from the-spirit and scope'of'the invention;

WVhat-is claimed is:

1. A method of making a .die, which consists of forming a circular beveled edge around a die blank, reducing the periphery of the die blank at its greatest diameter to prevent buckling, making an opening in the die blank and reducing the size of the opening by exertingia pressure on the beveled edge ofthe diegblankto forceithe material arounda member ofthefdesired shape.

2., A method of making a die, which consists of making an opening in the dieblank differing from the required opening, reduce ing the periphery ofthe die blank to-prevent buckling, and alteringtheopening inthe die blank by causinga 'cold flow-iof the material around the opening.

3. A method of making a die having a plane upper and-lower surface, which consists in forming a frusto-con-ical disk with a reduced portion at its greatest diameter to prevent buckling, making an opening of predetermined size through the'body of the disk, placing a member ofthe desired-shape Within the opening, and reducing theopening to a'shape determined'bythe memberby causing the material of the disk to flow laterally into engagement With the member by exerting a radially inwardipressure on the. blank.

4. A method of making a die, which consists in forming a disk :having a plane-sun face ,shapingthe sides of the diskto a frustoconical shape, forming aireduced portion at the base of the frusto-conical section, making an opening through the body of the disk, placing a member of the desired shape in the opening, and'causing the material of the disk to move substantially in planes parallel to the plane surface of the disk by exerting a radially inward pressure thereon .to change the opening to the shape of the member.

In Witness whereof I hereunto subscribe my name this 7th day ofMay, A. 13.1926. FREDERICK LAWRENCE

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