US440332A

US440332A - Island

Info

Publication number: US440332A
Authority: US
Publication date: 1890-11-11
Anticipated expiration: 1907-11-11

Description

0. D. ROGERS. DIE FOR MAKING ROLLED WOOD SCREWS;- No. 440,332.

(No Model.)

Patented Nov. 11, 1890.

INVENTEIFM WITNESS E5- L3 jm UNITED STATES PATENT OFFICE.

CHARLES D. ROGERS, OF PROVIDENCE, RI-IODE ISLAND, ASSIGNOR TO THE AMERICAN SCREW COMPANY, OF SAME PLACE.

DIE FOR MAKING ROLLED WOOD-SCREWS.

SPECIFICATION forming part of Letters Patent No. 440,332, dated November 11, 18$0. Application filed August 4, 1890, Serial No. 366,867. (No model.)

To aZZ whont it may concern:

Be it known that I, CHARLES D.RoGERs, a citizen of the United States, residing at Providence, in the county of Providence and State of Rhode Island, have invented certain new and useful Improvements in Dies for Rolling Gimlet-Pointed Wood-Screws; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form a part of this specification.

Dies of the class forming the subject of the improvement hereinafter described and claimed have been employed before in the manufacture of rolled thread wood-screws; but the particular type of screw to which my present improved die relates is that known as gimlet-pointed wood-screws.

Heretofore it has been the usual practice to provide the working-faces of thread-rolling dies with a series of inclined parallel ribs and grooves, the form or contour of the die, transversely taken through its face, being substantially alike throughout the length of the die; or, in other words, the ribs are so arranged that they produce the threads both upon the cylindrical or shank portion and the point portion simultaneously. An obj ection to the use of such former dies, irrespective of the shape of the ribs cross-sectionally, is that the portion of the dies adjacent to the point portion of the screw-blank when properly entered between them is beveled at an angle substantially like that of the blank. Such beveled portion extends throughout the length of the die and is provided with threadforming ribs and grooves, which are a continuation of the ribs and grooves formed on the plane portions of the die, substantially as before stated. Now when dies thus made are employed it is evident that the ribs are acting at once upon the entire portion of the blanks surface,which is to be screw-threaded. Such simultaneous action renders it difiicult for the blank to maintain itself in a proper position or relation until the completion of the screw-threads. It is, in fact, due to this cause alone that a considerable portion of the product is rendered imperfect or unsalable. Moreover, as a result of such former construction of dies itis clearly apparent that the cone-shaped or point portion of the blank must slip more or less upon the dies during its passage between them or while being acted upon by them, even though the cylindrical portion of the blank doesnot slip at all dur- 6o ing the operation.

The object I have in view in the invention illustrated and described herewith is to produce a die for rolling the threads of gimletpointed wood-screws, which is free from the objections or disadvantages before referred to as incident to the use of dies heretofore made.

To that end my invention consists, essentially, of a die having its lower or pointthreading portion cut away at the front end,

so as to not engage the cone-shaped point portion of the blank until the ribs have commenced to act fairly upon the cylindrical part of the blank. The lower portion of the die from this point gradually increases in height in a bevel form above the general surface, and is also provided with thread-forming ribs and grooves communicating with those of the main portion of the die until at or nearly to the back end of the die the raised bevel-shaped portion has a form transversely the counterpart of that to be given to the threaded screw-point. By means of my improved dies the screw-thread is gradually produced upon the point portion, the same commencing at the base of the point and terminating at or near the end of the screw when the dies have nearly completed their movement. In view of the foregoing it is evi- 9o dent that the blank is to a great extent prevented from slipping.

In the accompanying drawings, Figure 1 represents a side or front elevation of a thread-rolling die embodying my improvement, the same having its working-face provided with inclined ribs and grooves, and having the lower portion cut away and also provided with inclined ribs and grooves gradually increasing in length and communicat- 10o however, be advantageously used on curved dies.

r designates the ribs, and g the grooves formed between the ribs. I make no claims herewith to any specific form of ribs and grooves, as they may have any suitable shape transversely if adapted to the work required of them. The ribs should presentas little surface or area as possible to the screw-blank, so that they can be the more readily impressed into the metal. The form of the ribs and grooves should change so that at the opposite end of the die the grooves are the counterpart of the screw-threads to be produced.

The major portion of the working-face of the die longitudinally is fiat or substantially uniform in height throughout. The dotted line 7", Fig. 2, indicates the face of the ribs of such portion, and g the bottom of the grooves. By referring to said Fig. 2 it will be seen that the die has a wedge-shaped portion f along its edge, the same commencing at the right, or as drawn the entering end substantially flush with the ribs 0' or surface '1". From this pointit extends longitudinally of the die in an incline at until it reaches a point at near the opposite end, and from thence it extends, as at a, substantially parallel with but higher than the line 1" to the end, the vertical distance I) (see also Fig. 5)

between these lines a and r being substantially equal to the semidiameter of the screw at the core or bottom of the screw-thread. The inclined flat surface or portion a could be removed up to the line h, Fig. 1, without materially affecting the manner of the action of the-die upon the metal. Such'portion is left, however, because it is more convenient, and at the same time the die is rendered more symmetrical.

It will be seen by referring to Fig. 1 that the inclined or beveled point-threading portion 19 of the die extends rearwardly in a gradually-increasing manner, as indicated by the inclined line 71,, the line 3 .9, parallel with the upper edge of the die, indicating the intersection of such portion with the main portion 1". By reason of this construction the cone-shaped point of the screw-blank is gradually threadcd, the several ribs of a pair of such dies successively acting upon said point until at the end of the operation the screw drops from them fully threaded.

I claim A die for forging the threads upon a screw by rolling, having at its entering end a plane surface only, provided with ribs to form the threads on the cylindrical portion of the blank and toward the finishing end asurface inclined to the plane surface and corresponding to the surface of the point of the screwblank provided with ribs which engage in succession with the metal to form the threads on the point.

In testimony whereof I have aflixed my signature in presence of two witnesses.

CHARLES D. ROGERS.

Witnesses:

CHARLES HANNIGAN, GEO. H. REMINGTON.