US408528A - Island - Google Patents

Description

(No Model.) 2 SheetsSheet 1; 0. D. ROGERS.

' DIE FOR ROLLING DRIVE SCREWS.

No. 408.528. Patented Aug. 6, 1889.

WITNEEEEEI. INVENTEIHI vwys.

UNITED STATES PATENT OFFICE.

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

DIE FOR ROLLING DRIVE=SCREWS.

SPECIFICATION forming part of Letters Patent No. 408,528, dated August 6, 1889.

Application filed February 12, 1889. Serial No. 299,669. (No model.)

To aZZ whmn it may concern: spective view of my improved screw having Be it known that I, CHARLES D. ROGERs,a a slightly-modified form. A portion of this citizen of the United States, residing at Proviscrew is also broken away to show the form dence, in the county of Providence and State and arrangement of the grooves and threads,

of Rhode Island, have invented certain new which have a steeper inclination or pitch 55 and useful Improvements in Dies for Rolling than the threads shown in Fig. 1, the thread, Wood-Screws; and I do hereby declare the as drawn in Fig. 4, being what is termed a following to be a full, clear, and exact descripdouble thread and having two continuous tion of the invention, such as will enable othgrooves. Fig. 5 is a cross sectional view ers skilled in the art to which it appertains taken on line 0 0 of Fig. 4. Fig. 6 is a front 60 to make and use the same, reference being view of the die, in reduced scale, showingthe had to the accompanying drawings, and to working-face, the die being more particularly letters of reference marked thereon, which adapted to produce the threads and groove form a part of this specification. shown in Fig. 1. Fig. 7 is an end view of the The invention herein described relates to a die. Fig. 8 is an enlarged transverse sectional 65 die for producing a peculiar wood-screw, for view taken on line m 00 of Fig. 6. Fig. 9 is a which I have this day made an application front view of the die, also in reduced scale, for a patent. The die must produce 011 the having the ribs and grooves arranged to prosurface of a screw-blanlgfirst, shallow spiral duce the double grooves and threads shown in grooves having transversely a curved surface; Fig. 4, and Fig. 10 is an end view of the die. 70 second; threads at the edges of the groove In Fig. 1 is illustrated the conditions reraised slightly above the normal surface of quired in the die itself, and, as shown in Fig. the blank, and, third, a spiral normal portion 6, the shallow spiral continuous groor e a, of the blanks surface between two adjacent having transversely a curved form, and the threads. The die is straight, havingits workthreads 0 at the edges of the groove raised 7 5 ing-face provided with diagonal ribs, grooves, slightly above the normal surface m of the and plane surfaces corresponding to the blank, have, respectively, their counterpart grooves, threads, and normal surface of the in the diagonal raised ribs a, grooves c, and blank. The ribs rise, in part, above the plane plane surface on of the straight die D. In orportions of the die, and extend slightlybelow der to produce the threads and grooveon the 80 those surfaces, forming along the sides of the point portion 19 of the screw, Fig. 1, the face ribs grooves which produce the thread of the of'the die is raised along its lower edge, as atscrew. The ribs are convex transversely, and 25 Fig. 7. The inclination of the ribs and in operation are to be forced into the blank grooves is such as to produce single-groove 3 5 to the extent that they rise above the plane screws, the blank being entered at the right 85 portions of the die-surface. The metal which of the die, the ribs a first acting upon the is displaced should flow into and fill the point of the blank and gradually form the grooves formed between the ribs and the plane groove (1 and threads 0 upon the surface of portions of the die. The faces of the ribs the blank. The dotted lines or at the sec 40 which first come in contact with the blank tional portion of Figs. 1 and 4 indicate the 90 should be a little lower than those which comrelative pitch or inclination of the screwplete the grooves, in order that the displacethreads. The transverse area of the portion ment of the metal may be gradual. of a rib at, extending above the general face In the annexed drawings, Figure l repreor surface m of the die, is practically equal sents one form of my improved wood-screw, to the area of the two grooves 0, extending 5 a portion of the screw being in section to below said surface. Consequently the metal show the form of the groove and threads, one of the blank which is displaced by the ribs of continuous groove being employed. Figs. 2 the dies should fiow into and just fill the and 3 are cross-sectional views taken on lines grooves 0, thereby producing a screw having a: w and w w, respectively. Fig. 4 is a pera spiral groove (4 and screw-threads c, raised :00

at the edges of the groove above the normal surface of the blank, and having a spiral normal surface m between the threads.

In producing the screw shown in Fig. 4, and having a double groove, the angle of the ribs and grooves of the die form an inclination of about forty-five degrees, as shown in Fig. 9. The ribs a are very short at the end of the die (right) where the rolling commences, and gradually increase in length therefrom until the maximum is reached at the opposite end of the die. A pair of dies thus made and suitably mounted would seize a blank at a point midway of the portion to be threaded and gradually form the grooves and threads therein from said point in either direction simultaneously, the thread produced not extending to the point.

As before stated, the face of the ribs at the entering end, which first comein contact with the metal, should be a very little lower than the faces of the ribs farther along, which complete the grooves in the screw, in order that the displacement of the metal may be gradual. In the use of the die the plane portions m should be brought into contact with the normal surface m of the blank which is to be preserved in order to prevent its distortion by the displacement of the metal to form the grooves.

It will be understood that two (lies I) like that described are to be used in making screws, and that the blank is rolled between them as they move past each other in opposite directions. They are to be operatedin a machine similar to that described in a patent granted to me September 20, 1887, No. 370,353, and also in my patent of September 4, 1888, No. 389,168.

The amount of metal displaced by the action of the ribs a to form the groove a and threads 0 is indicated by the dotted line at t, Fig. 3, being a transverse sectional view of the screw represented in Fig. 1, and Fig. 5 shows a corresponding displacement of the metal of the screw shown in Fig. 4.

I claim- A die for rolling screws, provided with diagonal ribs and grooves for impressing a spiral groove into the metal of a screw-blank and raising the metal at the edges of the groove above the normal surface of the blank to form the threads of a screw, and with plane surfaces between the ribs corresponding to the normal surface of the blank to preserve such surface from distortion by the action of the ribs in forming the groove and threads.

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

CHARLES D. ROGERS.

Witnesses:

CHARLES HANNIGAN, GEO. II. REMINGTON.

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