US921463A - Spiral punch. - Google Patents

Description

`H. C'. ROBERTS.

, 1908. 921,463. l Patented May 11, 1909.

HARRY C. ROBERTS, OF MAXTON, NORTH CAROLINA.

SPRAL PUNCI.

No. saines.

Application filed July 2B, 1908.

S ecicaton o Letters Patent Patented May 1l, 1909.

Serial No. 445,762.

To all whom if: may concern.'

Be it 1Known that l, HARRY C. ROBERTS, a citizen ofthe United States, residing at Maxton, in the county of Robeson and State of North Carolina, have invented certain new and useful improvements in Spiral Punches; and l do hereby declare the following to be a full, clear, and exact description ofthe invention, suc-h as will enable lothers skilled in the art to which it appertains to malre and use the same, reference being had to the accompanying drawings, and to the letters of reference inarlred thereon, which form a part of this speciiication.

This invention relates to new and useful improvements in spiral punches especially adapted for making holes in belting for lacing the ends of belts together and the obiect of the invention is to produce a simple and eifrcient device of tais nature so constructed as to cut the hole without expanding and loosening the layers of which the usual belts are constructed and which is found to be a trouble where the apertures are made by the ordinary tapering punch. In belts which are commonly used and which are made up of layers, rubber and fabric, the formation of the holes by means of a solid unyielding punch, the layers which are fastened together are loosened from one another and which weakens the belt when laced together through apertures made by the ordinary punch.

More specifically, the present invention consists of spiral punch so arranged that, when it is turned either by hand or otherwise against the belt orother article to be punched, the cutting end of the tool will contract slightly by reason of a cutting lip projecting from the end of the device, thus causing a core to be cut of slightly smaller diameter than the normal expanded diameter of the punch and which will avoid the core adhering to the walls of the punch after the latter is withdrawn from the article in which the hole has been formed.

rl`he invention comprises various details of construction, combinations and arrangements of parts which will be hereinafter fully described and then specifically defined in the appended claims.

l illustrate my invention in the accompanying drawings, in which Figure 1 is a side elevation of my improved spiral punch. Fig. 2 is a cross sectional view through the cutting end of the punch and also a core showing the punch in its contracted forni while cutting the core. Fig. 3 is a similar view showing the core already cut and the punch removed from the belt or sheet in which the hole is made' and showing the cutting end expanded to its normal positien with a slight space intervening between the circumference of the core and the end surface of the punch. Fig. 4 is an enlarged detail view of the cutting end of the punch showing the cutting lip thereon, and Fig. 5 is a vertical sectional view through the punch.

Reference now being had to the details of the drawings by letter', A designates a spiral punch which is hollow and slightly tapering longitudinally, as shown in the longitudinal sectional view. ln the drawings said punch is shown as having a solid shank port-ion B with an end designed to i'it the socket of a bit stock. The cuttingvend of the punch, which is shown in the sectional view as tapering to a sharp edge, is provided with a cutting lip D which, when the punch is turned to theright, is adapted to cut into the sheet in which the hole is to be formed and, as the cutting lip engages the material and while the punch is being rotated, the thin tapering cutting end of the punch will have a tendency to contract thus cutting a core which is of a diameter slightly less than the diameter of the cutting end when the tool is expanded from its normal position, as shown in detail Figs. 2 and 3 of the drawings.

in operation, when the end of the punch is placed against the sheet of material through which the hole is to be formed and pressure applied to the tool as the latter is rotated to the right, said lip will outlinel and cut a cylindrical core and, as the cutting end is slightly resilient and when the cutting lip engages the material to be cut, it will have a tendency to contr ct the cutting end of the punch and, after the core has been cut and the punch removed from the sheet of material from which the core is cut, he free end of the tool will expand slightly as shown in Fig. 3, thus preventing the core being wedged in the punch as is commonly the trouble -with the usual form of punch in which no provi sion is made for the expansion of the same as l in the present instance. As the hollow portion of the punch increases in diameter toward the stock or Shank portion, the cores as they are successively cut will readily fall out through the spiral portions of the tool as will be readily understood.

v Thet I claim to be neT is:-

A hollow spiriti punch of a resilient metal, the end of which terminates in e circular outlined cutting` edge at right angles to the 5 length of the punch and extending into the opposite edges of the spiral part of' the punch and provided with e conVeXed lip projecting Witnessesz from said cutting` edge adjacent to the spiral ROBERT A. BosWELL, edge of the punch and merging into the edge l A. L. HOUGH.

of the spiral portion of the punch as set 10 forth.

ln testimony whereof I hereunto affix my signature in the presence of tWo Witnesses.

I t i l HARRY c. ROBERTS.

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