US1438940A - Wiredrawing die - Google Patents

Description

H. BLOUNT.

Dec. 19, 1922.

HARRY BLOUNT, OF OAK PARK, ILLINOIS, ASSIGNR' TO WESTERN ELECTRIC COM PANY, INCORPORATED, or New YORK,

N. Y., A CGRPORATION F .NEW YORK.

winnnnawmo mn.

application flied nay 12, i920. Semi Na'aeasas.

of Illinois, have invented certain new and useful Improvements in VViredrawing Dies, .of which the following is a full, clear, conoise, and exact description.

This invention relates to wire drawing dies, and has for its object to produce a form of die for wire drawing operations which will permit the drawing of wire therethrough at high speed without breakage of the wire and which will be efficient and accurate and will have a long life.

Investigation of former wire drawing machines has disclosed that they are necessarily limited in their speed of operation due to lack of dies capable of permitting 2c-the drawing of wire therethroughI at high speeds. These machines are now operating at speeds as high as wire can be commercially drawn through the dies used therein. After a long series of tests with dies ot' the types heretofore used and also with Various diierent designs of dies made up during the course of my investigation, I have discovered that the relation between the length and the diameter of the wirel reducing opening and also the contour thereof at the entrance end materially influence the pull requiredto draw the wire through the die, the accuracy of the lsize of the drawn wire, the speed at which wire l may be' drawn' through the die without breakage, and the length of time which the die can be used for a given size of wire. For example, there is a definite relation between the length of the 'wire reducing porio tion of the die and its diameter which 'will provide the greatest'resistance to wear on the die and at the same time will. provide for the minimum resistance to the pull of the wire through the die, while insuring that the wire will undergo a complete physical change from the larger to the desired reduced size. Also, it has been found that if the wire reducing opening is connected with the mouth` of the die by means of a curved portion which bears a certain relation to the diameter of the wire reducing opening, the amount of pull required to draw the wire through the die will be reduced to a minimum, thereby eliminating 56 the tendency of the wire to break and reducing the amount of friction between the die and the wire.

The dimensions which have been determined as best adapted for the stricture of the die are those in which the length of the reducing portion is approximately equal to its'diameter, while the contour thereof at the entrance to the wire reducing portion is rounded on a radius approximately i equal to twice the diameter of the smallest lportion of the wire reducing opening. Dies having this construction are capable of drawing number 19 to 40 vinclusive B. & S. wire gauge copper wire commercially at approximately 2500 feet per minute without breakage of the wire, whereas with former dies for drawing these sizes ot wire the machines have been operated at a maximum speed of reduction of 1600 feet per minute.

Dies made either from chilled iron or from diamonds having the .proportions abovedescribed are capable of highispeed reductions for a length ot' time that is commercially satisfactory.

i In thel drawings illustrating this invention 1- Fig. 1 is a vertical sectional view of a die illustrating this invention;

Fig. 2 is thesame as Fig. 1 with the wire i .by the wire as it is drawn through the die,

and

Fig. 4 is a fragmentary plan View of the die.

As shown in the drawings, 5 designates a die body which may be supported by a suitable supporting member 6 fragmentarily shown. At one end of this die there is provided a mouth or tapered opening 7 which 'is larger at its upper end than the diameter of a wire` 8 to be reduced and is tapered inwardly toward a straight sided reducing portion 9 ,which ,has the diameter of the drawn wire 10. The length L of the narrowed or reducing portion of the opening 9 should be approximately equal to the diameter or oZ of this'opening in order that the wire -will undergo. such ph sical changes that it will become complete y set in its reduced size before emerging from the die and the die will not be subjected to too great wear. AlsoV is length is not so great as to Aintroduce@extra friction to the drawing ofthe wire.

Connecting -the' mouth or tapered p0r' to twice the diameter d of the straight sided reducing portion 9. This curvaturev has been found to offer the least resistance to the drawing of the wire. lAt its lower end the straight' sided or reducing portion 9 is slightly beveled or rounded, as sho-wn at 13, to prevent cutting or abrading of the wire in case it becomes necessary to backup the wire in the die for any reason.

What is claimed is: l

1. A wire drawing die having a reducing portion in which there is a straight portion having as diameter.

2. A wire drawing die having a straight reducing portion the entrance into which when viewedl in crosssection is rounded on a radius approximately equal to twice the diameter of the straightreducing portion.

3. A wire .drawing die having a wire reducing opening in which there is a straight portion having approximately the same length as diameter and in which the approximately the same length ventrance end, when viewed in cross section,

is rounded on a radius approximately equal to twice the diameter of the straight portion.

In witness whereof, I hereunto subscribe my name this 28th day of April A.. D., 1920.

HARRr BLOUNT.

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