US1578172A - Making conical pins - Google Patents

Description

' March 23 1926.

Patented Mar. 23, 1926.

UNITED STATES PATENT QFFI CE.

VALENTIN nnrr'rnmrn, or meonsran'r, GERMANY, ASSIGNOR TO nno'rsonn WERKE ax'rmnonsnnnscmr, or BERLIN-WILMERSDORF, A CORPORATION OF GER- I MAKING CON IGAL PINS.

Application filed February 14, 1924. Serial- No. 692,845.

To all whom it may concern:

Be it known that I, VALENTIN RETTERATH, a citizen of the German Republic, residing at Ingolstadt, Bavaria, Germany, have in- 5 vented certain new and useful Improvements in Making Conical Pins, of which the following is a specification.

This invention "relates to a novel process or method for making conical like fastening pins, shafts and the like which are required to be of a slightly conical-like shape for securing structural parts together or for ready fastening to machine parts.

The usual practice in the manufacture of b such conical-like articles is to turn down cylindrical blanks to the requisite taper or to form such taper-like articles from suitable blanks by forging or sw'aging operations, and by subsequent smoothing by turning where extreme accuracy of contour is essential. The manufacture of the taperor conical-like articles, especially pins of the small dimensions to which this invention particularly Trelates, according to these prior methods is a rather expensive and uneconomical procedure on account of the expensive tools, the time and the skill of labor required,

According to the present invention the small conical-like fastening pins of the char acter herein considered may be manufactured in a much more satisfactory manner and with substantially greater and marked economy as compared with the prior methods. My invention resides generally inthe production of .such fastening pins and the like without the necessity for any turning andmilling operations or without the necessity for any. swaging or. forging operations, such articles being obtained directly in one operation from the small cylindrical blanks or rods. It consists generally in subjecting such blanks to one or more simultaneous lateral swelling and expanding operations, by pressure exerted radially to enetrate. the blanks to gradually increasing depths axially along circumferentially spaced longitudinal lines throughout those portions of the blanks to be increased in transverse dimensions, and causing the lateral and radially outward flow of the displaced metal along the sides of the resultant narrow and circumscribed grooves of gradually increasing depth in axial directions against abutment and conformation surfaces disposed between the circumferentially spaced lines and corresponding to the conformation of the article desired. The blanks are thereby expanded and caused to swell up to' the required transverse dimensions of gradually increasing effect in axial directions by "the single radial pressing operation and with no substantial diminution of the peripheral area or contact surface or impairment of the lateral strength of the resultant conical-like fastening pin, the resultant grooves, though slightly increasing in depth and width from one end to the other of the pin, being of such narrow and circumscribed proportions as compared to the intermediate portions of the pinat any point that the peripheral area thereof with its contact surface is only slightly reduced by this operation. This method incidentally results in the' new and improved article in that I the narrow and shallow grooves along the periphery of the pins permits the lateral flow of the expanded or bulged out metal therein when the pins are driven into cylindrical or conical holes.

For practicing my invention I have de vised a special apparatus including radially disposed and opposed forming and expanding die pressing members having recessed surfaces of slightly larger diameter than the cylindrical blanks and obliquely disposed to the axis of the blank and conforming to the conformation of the conical-like pins desired, together with narrow longitudinal forming and penetrating edges forming interruptions of said conformation surfaces and obliquely disposed to the axis in opposite directions to those of the forming surfaces, and these penetrating and cutting edges are adapted to form along circumferent-ially spaced lines on blank narrow and circumscribed grooves to effect the lateral bulging or expansion of the metal to the periphery thereof to a gradually increasing degree throughout the article.

For a better understanding of the invention, reference may be had to the accompanying drawings forming a. part of this ends of the pin being preferably rounded off. Figs. 2 and 3 are front and side elevations respectively of a conical pin made according to the invention and having four longitudinal grooves pressed -therein. Fig. 4 shows the arrangement of the stamping members. Fig. 5 is an elevation partly in section illustrating the action of the stamping members upon a pin blank. Figs. 6 and 7 are upper 'and lower plan views corresponding to the pin in Fig. 5. Fig. 8 shows in side view a fitting pin 9 made by this arrangement; and Fig. 9 shows a double conical shaft constructed according to the invention.

Referring to the drawings a plurality of radial stamping members or dies 6 are employed of a height equal to the conical pin or the like tobe made. The members 6 are furnished with projecting ridges 8 which are adapted to press into the blank when a pressure is applied thereto radially, the material of the blank being thereby caused to.

move outwardly to fill the space between the dies and to form the conical fitting surfaces against the recessed surfaces 7 of the dies.

By reference to Figs. 5, 6 and 7 it is seen that the ridges 8 are inclined inwardly and the recessed surfaces 7 outwardly of the axis of the blank which thus remains circular at the1 lower end and tapers towards its upper en In Figs. 2 and 3 a pin having four grooves formed in this manner is shown, whilst in Fig. 9 a shaft having a double conical surface is shown. By this process the cylindrical blank is readily pressed to shape and pins with conical surfaces produced with.

great ease and exactitude.

I claim:

1. The method of forming tapered fastening pins with elongated shallow grooves, comprising subjecting a section of stock to limited deforming pressure, radially applied, in a manner to form the grooves axially of the pin and to progressively enlarge the diameter of the pin uniformly toward one end without substantially diminishing the peripheral contact area or the lateral strength of the stock.

2. The method of forming a tapered fastoning pin from a cylindrical blank, which comprises forming shallow grooves in the blank which grooves increase in depth toward onevend and are along circumferentially spaced longitudinal lines, by the application of limited pressure radially and simultaneously applied by a plurality of deforming members, the pressure bein only sufficient to form the grooves and t ereby shape the pin to its taper form without substantially reducing the peripheral contact area or the lateral strength of the blank.

3. The method of forming tapered fastening pins with shallow grooves extending lengthwise of the pin, comprising subjecting a length of cylindrical stock to limited deforming pressure which is radially applied and sufficient only to form shallow grooves of increasing width and depth along circumferentially spaced longitudinal lines and to laterally displace small quantities of metal from the. grooves toward the periphery of the pin to give the tapered dimension Without substantially diminishing the peripheral contact area or the lateral strength of the stock. y

In testimony whereof I have hereto affixed my signature.

VALENTIN RETTERATH.

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