US262892A - Wood-screw - Google Patents

Description

' '(ModeL) 'J. M. GQODRIDGE.

WOOD SCREW.

No. 262,892. Patented Aug.15, 1882.

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UNITED STATES PATENT OFFICE.

JOHN M. GOODRIDGE, OF BALTIMORE, MARYLAND, ASSIGNOR OFONE-HALF TO DAVID HUMPHREYS, OF NORFOLK, VIRGINIA.

WOOD-SCREW.

SPECIFICATION forming part of Letters Patent No. 262,892, dated August 15, 1882.

Application filed March 25, 1882. (ModeL) To all whom it may concern:

Be it known that I, JOHN M. GOODRIDGE, a citizen of the United States, anda resident of Baltimore, in the county of Baltimore and State of Maryland, have invented a new and valuable Improvementin Screws and I do hereby declare that the following is a full, clear, and ex act description of the construction and operation of the same, reference being had to the annexed drawings, making a part of this specification, and to the letters-and figures of reference marked thereon.

' across the bottom of the Figure l of the drawings is a representation of a side view of this invention. Fig. 2 is a bottom view. Fig. 3 is a top view. Fig. 4 is a perspective view of the head.

This invention has relation to wood-screws having under-beveled heads; and it consists in the formation at each end of the drive-slot of an oblique shallow notch having its apex at the neck of the screw, an abrupt oblique reaming-shoulder extending from the neck slot back of the same, and a shallow under-beveled surface in front of saidshoulder, all as hereinafter set forth, and particularly pointed out in the claims appended.

In the accompanying drawings, the letter a designates the head of the screw, having the under-beveled surface b and the drive-slot 0 extending across its top. The shank d joins the cone-shaped under bevel of the head at the neck 6, and the thread 9 extends from the shank d around the core h of the stem to the point 7c. At each end of the drive-slot, in the side of the under bevel, b, is made a shallow angular notch, 11, the apex p of which is at the neck 6 in advance, or at the left of the driveslot, and from the apex extends upward and rearward obliquely the reamingshoulder 8 back of said drive-slot to the top of the screw.

In front of this shoulder the under-beveled and depressed surface 1' of the notch extends in front of the drive-slot to the under bevel, b,

of the head. The reaming-shoulder s intersects obliquely the bottom of the drive-slot, as

The point k of the screw is pywhich extend shown at t. ramidal, having four walls, w,

from its extremity to the threaded portion of the stem, the thread 9 commencing at the base of the point, as indicated at z. This pyramidal point is designed to act efficiently in opening the woody fibers for the passage of the screwstem, separating the fibers in a free manner, so that the threaded stem will follow easily and without heating up, and consequently without splitting the wood. The reamingshoulders s of the head form the countersink or conical seat in the woody material with ease, even when the head of the screwis turned entirely below the surface, as the woody particles which are separated by the reamingedges are guided thereby upward and outward through the openings at the ends of the drive-slot.

Asthe depressed surface 1' of the notch is but little below the under bevel, b, of the head, it is apparent that but little material istaken away therefrom at the corners of the driveslot, so that a full bearing is afforded to the end of the screw-driver; and as the pyramidal point opens the way freely for. the stem the screw is easy to drive and the head not so liable to be carried away or injured.

A wood-screw having vertical cutters at opposite ends of the drive-slot and oblique walls at the opposite side of the drive-slotand at the ends thereof for the escape of the chips when the screw-head is forming the countersink in the wood is old, and is not claimed herein. A triangular screw-point having concave face and cuttingedges is also old, and a harpoon-pointed screw has been used before my invention.

Having described this invention, what I claim, and desire to secure by Letters Patent, 1s-

1. A wood-screw having at each end of the drive-slot a shallow oblique notch, at, having its apex at the neck of the screw, an abrupt oblique reaming-shoulder, 8, extending from the neck to and back of the drive-slot and intersecting the bottom of the drive-slot, and the depressed shallow under-beveled surface 1' in front of said shoulder, substantially as specified.

2. The wood-screw having the square py- In testimony that 1 claim the above I have ramidal point 70, the thread g, commencing at hereunto subscribed my name in the presence the base of said point, and the head having of two witnesses.

the oblique side notches, n, at the ends of the JOHN M. GOODRIDGE. drive-slot, and the shoulders s, intersecting the Witnesses:

ends of said slot and extending back of the THEO. MUNGEN,

same, as specified. JAMES J. SHEEI-IY.

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