US1202928A - Screw-point for well-tubings. - Google Patents

Description

J. WALLACE.

SCREW POINT FOR WELL TUBINGS.

APPLICATION FILED MAY t9. I916.

1 3 928 Patented Oct. 31, 1916.

JOHN WALLACE, OF HOUSTON, I! 1 SCREW-P0131 1 FOR WELL-TUBINGB.

LQUWAWS.

Specification of Letters Patent.

Patented Oct. 3t, iaie.

Application filed May 19, 1916. Serial No. 98,581.

To all whom it may concern Be it known that I, JoHN WALLACE, a citizen of the United States, residing at Houston, in the county of Harris and State of Texas, have invented new and useful Improvements in Screw Points for Well- Tubings, of which the following is a specification.

This invention relates to a screw point for well tubing, and one of its objects is to provide a screw point or anger which is designed to be fastened to the end of the well tubing to facilitate its passage down into the earth in the operation of boring a well, and which when the bore is completed may be allowed to remain as a fixed support for the lower end of the well tubing.

Another object of the invention is to provide a screw point or auger of novel and improved construction which is designed to easily cut its way into the earth in the operation of drilling the well, and which is detachably coupled to the tubing in such manner as to permit removal of the tube in the event of a failure 'to strike water or other fluid, or to enable the tubing to be cleaned when choked with sand or other material.

A still further object of the invention is to provide a drill point for well tubing which embodies a thin spiral cutting flange, without taper and of a comparatively low pitch, approximately a twenty-two degree pitch, and which is compoundly curved, so as to cut with ease through clay and other gummy and dense soils and lift and back the same to facilitate the drilling action, thus obviating the well known objections to tapered and spiral cutters of high pitch and some material thickness which are liable to clog in attempting to out through earth of the character described.

The invention consists of the features of construction, combination and arrangement of parts hereinafter fully described and claimed, reference being had to the accompanying drawing in which:

Figure 1 is a side elevation of the device. Fig. 2 is a vertical longitudinal section on the line '22 of Fig. 1. Fig. 3 is a horizontal transverse section on the line 3-3 of Fig. 1. Fig. 4 is a horizontal transverse section on the line H of Fig. 1.

In carrying my invention into practice, I provide a drill or screw point 1 composed of cast iron, steel or other suitable material, and comprising a body portion formed of a series of stepped surfaces 2, 3, 4 and 5 of gradually decreasing diameters, and terminating in a conical entrance point 6. The portions of different diameters will vary, of course, in number according to the length of the drill point, but in every case Wll be of gradually diminishing diameter downward and gradually increasing diameter upward, for a purpose hereinafter described. The portions 2, 3, 4t and 5 are preferably cylindrical in form, as shown, in order to secure a desired action on the loosened earth.

The stepped portion of the body of the drill is provided with a cutting blade 7, of

spiral formation, and extending continuously from the top of the portion 2 to the middle portion of the point 6, and provided at its lower extremity with a depending V- shaped cutting edge 8. This blade is in the form of a comparatively wide and thin plate, of low spiral pitch, preferably about twenty-two degrees, and which is devoid of a tapering formation, that is increasing thickness toward the stock, being approximately of the same thickness throughout The blade is, however, compoundly curved each of its convolutions being provided with an elevated or crest portion 9 between adjacent convolutions, so as to efiect a desired and efficient lifting and loosening action upon the soil.

As a result of the described construction of the drill, the tendency of drills having a general longitudinal taper or blades of tapered form increasing in thickness toward the stock to clog and bind in the earth, is avoided, such action being due to the tendency of the material to pack between adjacent convolutions and thus ofier a bindrance to the cutting action of the drill and its passage through dense and hard materials. By using a blade which is in the form of a plate of equal thickness throughout the objection mentioned is not only overcome, but a broad shelf is provided on which the dirt may lodge, and as the blade is compoundly curved it will exert a lifting and loosening action on the earth with obvious advantages. Furthermore, by providing a stock with stepped portions of gradually increasing diameters upward, the earth cut and loosened up by the drill will be gradually forced outward as it accumulates and compact against the sides of the well to gradually increase the density'as the drilling action proceeds. Thus While the drill may cut its way with ease and freedom even; through heavy earth, such as clay and guminy soils it will be seen that the drill; will pack itself in place and thus is adapted to form a stable bottom support for the well tubing.

The body or stock of the drill. is provided at its upper end with a threaded extension 10, which is of cylindrical form, and is adapted to be engaged by the thread of a coupling sleeve 11, which is adapted to connest the same with the lower threaded end 12 of the perforated screen section 13 of the well tubing, whereby upon the drilling of the well the drill point may be left in position to farm mable fixed support for the lower end of the well tubing. For the purpose or providing a secure connection between the extension 10 and sleeve 11, the said extension and sleeve are provided with coinciding tapering slots 14 to receive a wedge key 15, whereby the drill is locked to the coupling member against any possibility of casual disconnection during the drilling action at all other times except when it is desired to efiect a release of the tubing and a coupling projection at its opposite end, said stock comprising a body having stepped portions of gradually increasing diameters upwardly, and a spiral cuttin blade encircling said stepped portions sai blade being in the form of a plate of equal thickness throughout'and of a low spiral pitch, said blade having its convolutions united by compoundly curved lifting portions.

In testimony whereof ll aflix my signature.

JOHN r WALLACE.

Witnesses I I H. P. MEssEReAU, PHILIP THARR;

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