US2579720A - Drill device - Google Patents

Description

Dec. 25, 1951 ATKlNSON 2,579,720

DRILL DEVICE Filed NOV. 12, 1948 1' |5 INVENTOR "f THOMAS P. mmsou it; :5. J BY m ATTORNEYS Patented Dec. 25, I951 UNITED STATES PATENT OFFICE DRILL DEVICE Thomas P. Atkinson, Newport Beach, Calif. Application November 12,'194s,'seria1 No. 59,523

4 Claims.

This invention has to do with drills and, while not limited to such use, is particularly suited for use as an impact drill in mining operations and the like where no liquid is circulated around the drill and through the hole to remove cuttings.

Usually such drills are operated by conventional jack hammers which impart the percussive blow to the drill stem, the drill bit carried by the stem being usually shaped to impart rotative movement in response to the impact. In such drilling there is a tendency, particularly in certain earth formations, for the drill to become wedged against removal from the hole due to cuttings tending to wedge behind the drill when the drill is pulled axially outwardly of the hole.

It is an object of my invention to provide a drill device which is easily removable from drill holes bored in any earth formation.

A further and more particular object is to provide a drill stem which has means for loosening the drill in the hole to permit its ready removal.

Other subordinate objects and accomplishments of my invention will become apparent from the following detailed description of a presently preferred embodiment, for which purpose I shall refer to the accompanying drawing, wherein:

Fig. 1 is a side elevation;

Fig. 2 and Fig. 3 are sections taken on lines 2-2 and 3-3, respectively, of Fig. 1;

Fig. 4 is an enlarged fragmentary side elevation;

Fig. 5 is an enlarged cross section of one of the vanes on the drill stem; and

Fig. 6 is a side elevation of the device in a drill hole.

Referring now to the drawings. I show at 5 a drill stem having a flange 6 at its upper end and a reduced diameter upper end 1 of angular cross section to fit in a socket in an additional length of drill stem or in an impact member (not shown).

The stem is preferably, though not necessarily, of hexagonal cross section, and has a relatively large diameter, substantially cylindrical lower end portion 8 and a portion 9 tapering from the portion 8'to the relatively small diameter upper stem portion.

Depending axially from the lower end of the stem there is a screw threaded tapered pin I0 for attachment to a drill bit l5. While my invention is not confined to the use of any particular bit or drill element, the bit illustrated is a conventional star bit having a cylindrical body portion 20 with formation impacting end members or cutters 2| whose formation engaging faces are angled to cause rotation of the bit in the direction of the arrow 22 as the bit is driven into the formation.

' The cylindrical lower end portion 8 of the stem is preferably the same diameter as the body of the bit, so as to prevent any earth from impacting beneath the bottom end of the stem above the bit.

The cylindrical portion 8 oi the stem is provided with spirally disposed grooves 25, here shown as three in number, spaced apart circumferentially of the stem, although, of course, any desired number of grooves may be employed. These grooves extend into the tapered portion 9, although they gradually decrease in depth toward the top end of the tapered portion-that is, as the grooves traverse the tapered portion, they gradually reduce in depth due to the tapered or conical shape of the portion 9.

In each of the grooves I secure, as by brazing or welding, a vane 30. Considering that the tool, when in operation, is caused by the shape of the bit to rotate in the direction of the arrow 22, in such normal operation the left-hand edge of each vane would be the leading edge We and the opposite edge would be the trailing edge b. Preferably, throughout the cylindrical section 8, the leading edge 30a of each vane is substantially flush with the peripheral surface of the portion 8, and this is preferably true also as the vanes traverse the tapered portion 9, since, in normal operation, it is not desired that the vanes perform any reaming action. However, the faces of the trailing edges 3% project radially from the periphery of the stem to an extent not greater than the diameter of the hole H cut by the bit, the outer surface 30c of each vane declining from its normal trailing edge to its normal leading edge. As will be best seen in Fig. 4, the trailing edge projects radially from the peripheral surface of the stem to a gradually increasing extent from the cylindrical portion 8 towards the upper end of the tapered portion 9.

The vanes are spiralled in a direction opposite to the direction of normal rotation of the stem during drilling operations, so that when the stem is pulled axially upwardly from the hole the faces 30?) of the vanes engage any loose earth in the hole above the bit and imparting a reverse rotative movement to the stem-that is, in the direction of the arrow 35-preventing the tool from wedging in the hole. Since the edge or face 39b of each vane gradually decreases in thickness towards the lower end of the stem portion 8, which is slightly smaller in diameter than the hole, the

' the lower end of "said stem and shaped to impart rotation to the drill stem in a given direction in response to percussive engagement of the bit with the bottom of a hole being bored, spirally longitudinally disposed circumferentially spaced vanes projecting from the peripheral surface of the stem, the outer surfaces of the lower end portions of said vanes and maximum diameter portions of the bit defining the diameter of the hole being bored; each of said vanes spirally retreating from its lower end to its upper end when viewed in relation to the direction of rotation of the stein and bit during normal boring operation, and each having a sloping normally leading surface and a radial normally trailing surface. H

2. In a drill device, the combination with a percussive drill bit having a formation engaging surface arranged to impart rotative movement to the bit in a clockwise direction in response to percussive e ga em nt of the bit against said formation, of a drill stern having acylindrica-l portion connected to said bit, and having perip'h 7 arm vanes spirally declining from the 1ower and to the ripper end of -said drill stern counterclockwise direction, said vanes resentmg sloping formation engaging surfaces facing toward said direction of rotation and radial surfaces facing in the opposite direction, whereby upon rotation of the bit and stem in the latter direction to move looseformation downwardly from above the bit.

3. In a drill device, the combination with a percussive drill bit having a formation engaging surface arranged to impart rotative movement to the bit in a clockwise direction in response to percussive engagement of the bit against said formation, of a drill stem having a cylindrical 1 portion connected to said bit, having a portion above said cylindrical portion tapering to a smaller diameter upper end portion and having peripheral vanes spirally declining from the lower end to the upper end of said drill stem in a counterlockwise direction, said vanes presenting sloping formation engaging surfaces facing toward said direction of rotation and radial surfaces facing in the opposite direction, whereby upon rotation of the bit and stem in the latter direction to move loose formation downwardly from above the bit.

4. In a drill device a drill stem formed at its bottom end to receive a percussive drill bit shaped to irnpartrotation thereto in a clockwise direction in response to percussive action, said stem having a cylindrical lower end ortion and tapering upwardly to a relatively small diameter cylindrical upper portion, and having peripheral grooves traversing said cylindrical and tapered portions, said grooves spirally dec'ning 1m their lower ends to their upperenas 111a count clockwise direction, and varies having their'in edges secure" said respective grooves, said vanes presenting sloping surfaces racing said direction of rotation and presenting radial surfaces facing the opposite direction.

THQMAS P. ATKINSON.

REFERENCES CITED The "re-mowing references are -61 record mine a file of this patent:

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