USRE14958E - Method of making nut-blanks - Google Patents

Description

E. HOLLINGS.

METHOD OF MAKING NUT BLANKS.

APPLlCATiON FILED AUG.30, 1920.

Reissued Oct. 12, 1920. 14,958.

UNITED STATES PATENTIOFFICE."

ERNEST HoLLINGs. oE CLEVELAND, 01:10;

' METHOD oE MAKING NUT-BLANKS.

Specification of Reissued Letters Patent. Reissued- Oct 12, 1920,

ori inal no} 1,842,676, dated June a, 1920, Serial No. 175.093, filed June 16, 1917. ap lication" for reissue I t filed August 30, 1920. Serial No. 407,058.

To all whom it may concern Be it known that I, ERNEs'r Ho'LnrNos, a

This invention relates to the manufacture of nut blanks, by indenting a bar at intervalsand severing the partially shaped nut' blanks therefrom. The invention has particular relation to the method of forming the nut blanks, and is an improvement upon the bar and method of, my Patent No.

- 1,231,891, granted July 3,1917, formanu factu-re of blanks for nuts.

According to the method of my prior application a bar of rectangular cross section 'is thickened along two opposite side faces,

those faces which later become the side faces of the nut blanks, in a manner toconcave both of the other two faces of-the bar. This i bar is then indented at intervals and the partially shaped blanks severed and pressed ina die.

Experiencein the-practice said method 1 particularly. with .theharder American metals as distinguished from the softer British iron, discovered the fact that it was advisable to turn the bar over after severing each nut to minimize, so far as possible the tendency to leave small transverse grooves in the top face of the pressed blank. These grooves or unfilled depress ons were really traces of the concavity at the bottoms of the indentations accentuated by the tend- .ency of the metal to draw down during the cutting off step. Although nut blanks of commercial quality can be obtained without reversing the bar trace of this groove 7 in the finished blank is minimized by reversing, but even then, with hard metal, a very heavy pressure, not practical in ordinary working, is required to fillout and erase the groove by the flow of surrounding metal, es-

pecially in its chilled condition as the re sult of indenting. I

The object of the present invention, therefore, is to provide a method which enables .better nut blanks to be formed without reversing the bar, thereby saving the time of turning and materially increasing the rate of production; and which enables a practically perfect blank tobe produced without unrollihg mill, as is usual.

usually heavy pressure in the die, thereby saving considerable wear and tearon the tools and machine and also adapting the process tojbe carried out with the harder metals'with the same orbetter results than when used for the softer British iron.

In the drawings, Figure 1 represents a perspective view of a bar forformi11g crowned nuts, wlth a portion of said bar .1, and illustrating a bar suitablev for man ufacturing flat faced nut blanks, or blanks having no crown. i r

Referring to Fig. '1, the bar there shown has a cross section suitable for the formation of crowned nuts, although, as will appear, the invention may be practised for manufacturing flat faced nuts and is also applicable as well for rectangular as for hexagonal nuts. V 1

The bar shown in Fig. 1 may beproduced in any suit-able manner, for example, in a opposite faces, marked 1, said bar is thickened- In other words, in a direction in line with-the axis of the formed ,nuts thebar is thicker at said two faces l'than at its central portion 2. The thickening is effected in a manner to provide a concavity or channel 3 in one face, only of the blank bar, and specifically this concave face is that face of the bar which is later presented to the cut off tool. Substantially, the thickening efiect is produced by the addition to i the bar of thesmall substantially triangular portions marked 4, which extend out beyond, the dotted line. 5, representing the normal fiat face of the bar.

For making flat faced nuts, to-wit, nuts having no crown, the opposite face 6 of the bar is flat from side to side, as indicated in Fig. 5, but for making crowned nuts this face of the bar is roughly given the contour of the crown to be produced, as by slightly curving the face 6 at the two opposite sides of the bar, as'indicated at 7, Fig. 1.

The bar, so formed, is submitted to the acnut making machine, the tools of which are Along two of its tion of the forming tools of a'well known 1 10 above andbelowand indent the thickened" plies the necessary metal for partially shown in the drawings. These tools include the indenters 8, having V- shaped end Working faces 9, the die block 10, the cut off tool 11, its companion compressing tool 12, and the central a'line'd punches 13. The bar is fed into the said machine at intervals With the concave facepresented to the cut off tool 11. During the period-or interval-between feeding motions the several tools described' complete' their functions. The first step is the operation of the indenting tools 8, Which come in from facesor edges 1 of the bar, as shown in Fig. 3. This operation carries a portion of the thickened" edges of the toward its thiir ner central portion, as indicated by the shade lines 14, thereby supplying the deficiency in the thinner central portion of the bar. The cut off tool 11 next moves in and shearsoff the partially formed blank from the end of the bar and carriesit into the die 10, Where it is'compressed between'the cut off tool lland its companion alined tool 12.

"in this compressing operation there is little difficulty in producing a fiat face'on that side of the blank presented to the cut'ofi tool 11. The main difiiculty, heretofore, has

been in the production of a smoothface on the opposite side of the blank, and, asheretofo're stated, this face of'the blank hasjcan ried traces of the concavity in one ofthe faces of'the blank bar from which the nut was sheared. However, in the present bar, the

opposite face of the bar, indicated at G, is

not concave, and even may be slightly convex, as when crowned nut blanks aJe made. Consequently, this face of the bar bears no traces of a concavity or channel 40 Y "form.

tral portion of the nut blank is filled out by and is finished in practically perfect smooth As'in my prior method, the cen- "central portion'at the bottom of the longitudinal concavity. In other Words the depth of the side faces 1 of the bar is usually equal to i-0r 'cpossiblyslightly greater" than the thickness of the finished nut, Whereas the tliickness of the bar from the base of the concavity in one face to its opposite face 6 is less than the thickness of the finished nut. possibly about U three quart'ers thereof. Therefore the blank bar is always thicker along the two-edges than at its middle portion. This method produces nuts of the form lshovvnin Fig. 4, With a perfectly fiat'face 15 on one side, a face on its opposite sidewhi'ch may be either fiat or crowned in accordance ith'the shape ofthe blank bar, and with.

side faces which are perfectlytrue and with corners fully filled, out. The Imethod does not entail any reversing ofthe barj between the steps of severing successivefnuts. Conse'quentlythe time required for this reversing operation is saved andthe machine opcrates at'a higher speed and with greater output. Moreover, the metal is so handled by. the formation of the initial blank bar and in its treatm'entby the tools that eX- cessive or unusually heavy pressure of the tools is not required and the'fully filled out blank "is produced With normal pressure "such as can vbe obtained fromthe' average machine Withoutfi-mposing unusually heavy duty thereon. Atthe same'time, the method can be practisedWi-th the harder grades of 'nietal, and is not limited to softer metals such asjthe soft Britishiron.

"llhatI-claim is: i

1'. The method of manufactur1ng nut blanks, oonsistmg in; mdentlng at intervals blank bar thickened at its edges to provide a longitudinal concavity on one side only, and shearing successive nut blanks from sa'id'bar. e a I v '2 In a method -of 'manufacturing nut blanks, the step ofindenting at intervals-a blank bar 'thick'enedjat itsedges to provide a longitudinal concavityon oneside only 'a'nd a longitudinally extending convexity upon its opposite side.

In testimony whereof I aflix my signature.

ERNEST HOLLINGS.

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