US2742263A - High speed percussion type drill stem - Google Patents

Description

p 17, 1956 R. G. CLUGAGE 2,742,263

HIGH SPEED PERCUSSION TYPE DRILL STEM Filed June 18, 1948 2 Sheets-Sheet l livwmwywwxm M IIH MWi/WWA Pale/v (/0 aye April 17; 1956 Filed June 18, 1948 R. G. CLUGAGE 2,742,263

HIGH SPEED PERCUSSION TYPE DRILL STEM 2 Sheets-Sheet 2 al mm United States Patent This invention relates to a high speed percussion type drill. More particularly,-it relates to a drill comprising a reciprocated rapidly in a bore or Well to perform the drilling operation by impact or percussion.

a In drills of the type referred to, a bit is provided and to the bit is secureda drill stem. The assembly is reciprocated by a cable which is operated from the top of the well. The tool is rapidly reciprocated, and by impact of the bitagainst the earth or stone formation which is being drilled the drilling is accomplished. The bottom of the'well'is suppl'iedwith water, and from time to time the drilling operation is discontinued, the drill assembly is withdrawn and the mixture of water and cut 7 tings is baled out.

'Drills of this type are used to drill relatively shallow wells, such as water wells. The advantage of this type of drill over rotary drills is the considerably less expensive construction of the drill and of. the equipment required at the surface of the well to'op'erate the drill. However, the effectiveness of this type'of drill is greatly limited. by

reason of the fact that it cannot be operated efficiently at high speed. Thus, if it is attempted to operate such a drill at a speed in excess of about 50 strokes per minute, the impact of the drill upon the formation is very inefficient.

It is an object of this invention to provide an improved type of percussion drill.

a It is a further object of the invention to provide a'high speed percussion type of drill which operates efficiently at speeds of the order of 100 strokes per minute. It is a still further object of the invention to provide a high speed percussion drill of simple design such as can be fabricated with a minimum of modification of a standard percussion drill.

These and other objectsiof theinvention willbe ap 'parent from the ensuing description and theappended of which is connected by means of a swivel joint to a cable 6. The bit 1 and the lower end of the drill stem 3 are provided with polygonal neck portions and 11,

' drill bit, a drill stem, and a cable, and wherein the drill is V respectively, to engage a wrench, and an upper collar v 2,742,263 Patented; Apr. 17., 19 5.6

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upon the collar 12. A hollow weight 14 having a central longitudinal bore 15 also encircles the drill. stem 4, the

bore 15 being of sufficient diameter that the drill stern will reciprocate freely therein.

Referring now to Fig. 2, the drill bit 1 and the cable 6 are the same as in Fig. 1, but a hollow stern 16is provided instead of a solid stem as in Fig. l, and. a coil spring 13 and a solid weight 17 are disposed within the hollow stem 16, as shown, with the spring resting. on the bottom of the stern and the weight resting on the spring.

16 is such as to allow the weight 17 to reciprocate freely therein. p

In operation, the drills shown in Figs. 1 and 2 are reciprocated in the usual manner but are capable of chicient operation at much greater speeds, .e. g;, to

strokes per minute; At such speeds, and with the usual drill, the impact force of the bit on the downstroke would be negligible or zero owing to the fact. that upward acceleration exerteduduring the upstroke exceeds the acceleration of gravity on the downstroke. In. the drills of Figs. 1 and 2, however, at speeds of the magnitude mentioned, the weight 14 or 17 remains substantially stationary, thus causing compression of the spring 13 on. the upstroke. On the downstroke the expansive force of the spring adds to the force of gravity, thus allowing va much more rapid reciprocation of the bit. p p q The weight 14'or 17 is preferably several times, :e. g. three times the weight of the bit. Where a deep well is being drilled, say at 1000 feet, thusaddi-ng substantially to the weight of the cable, a heavier weight and a stronger spring should be used. Preferably, also, the drill is brought quickly to a high speed, and the length of stroke is preferably about two feet and the, speed isabout 150 strokes perminute in a well of ordinary depth, say down Referring now to Fig. 3, a solid stem 4 and a hollow weight 14a are employed, as in Fig. l. However the hollow weight 14a'is provided with an enlarged bore or cavity 20 at its upper end providing ashouldef 21and the solid stern 4 is provided with a flange'o'r collar 22 secured thereto about midway of the cavity 20." Disposed below the collar 22 is a coil spring 23 encircling the stem 4 and resting upon the shoulder 21, and disposed above the collar 22 is a second coil spring 24 encircling the stem 4 and resting upon the collar 22. As also shown the hollowweight 14a is provided with a cap 25 threaded onto the weight and removable therefrom for purpose of assembly and repair. Also, the walls j of the cavity 20 are slotted as at 26. Conveniently, four such longitudinal slots may be provided, spaced at intervals of 90 about the periphery of the weight. As also shown, a swivel joint 5a is provided at the bottom of the stem 4.

Referring to Fig. 4, a hollow drill stem 16, a solid weight 17 disposed within the hollow drill stem and a.

coil spring 13 disposed below the solid weight are provided as in Fig. 2. However, a second coil spring 27 is also provided, being disposed above the weight 17 and resting thereon. Referring to Fig. 5, a solid stem 4 and a hollow weight 30 are employed, the weight 30 being formed of two segments 30a and 30b in'threaded engagement at 31 to provide access for assembly and repair. A cavity a is formed in the weight 30, partly in the lower segment b and partly in therupper segment 30a, as shown. The solid stem 4 is provided with-a flange or collar 22 as in Fig. 1, and a coil spring 23 encircles the stem below the collar 22 and rests upon the shoulder 21, while a second spring 24 is disposed above the collar 22 and also encircles the stem. As in Fig. 3, longitudinal slots 26 are provided in the walls of the cavity 20a.

The embodiments illustrated in Figs. 3, 4 and 5 have in common the feature of a pair of coil springs. The coil springs 24 in Figs. 3 and 5 and the coil'spring 13 in Fig. 4 are compressed on the upstroke, as in the case of 'the coil springs 13 in Figs; 1 and 2, and serve to accelerate the bit on the downstroke. These springs (13 and 24) may, therefore, be called the operative springs. The springs 23 in Figs. 3 and 5 and the spring 27 in Fig. 4 are what may be called limit springs, which serve to limit the downstroke of the bit to prevent too hard a blow being struck.

In operation, the drills of Figs. 3, 4 and 5 are employed as described above with reference to Figs. 1 and 2, and similar considerations as to relative masses of the weight and bit are applicable. The longitudinal slots 26 in the drills of Figs. 3 and 5 are provided to allow egress of water which enters the cavity 20 or 20a. In the absence of such openings the collars 22 would act as pistons, thus retarding reciprocation of the drills.

It will thus be seen that a high speed percussion drill has been provided which is effective in drilling at speeds two and three times the maximum efficient speed of ordinary percussion drills; that the design is simple and the parts easily fabricated; and that modification of an ordinary percussion drill to embody the features described, may be accomplished at very low cost.

While I have shown the preferred form of my invention, it is to be understood that various changes may be made in its construction by those skilled in the art without departing from the spirit of the invention as defined in the appended claims,

I claim: a

1. A percussion drill comprising a drill bit, a drill stem attached directly to said drill bit, said drill stem being provided with a projecting member, a coil spring encircling said drill stem and supported upon said projecting member, and a hollow weight receiving said drill stern, freely movable therealong and resting upon said spring, said weight being of sufficiently greater mass than said bit and stem to maintain the weight substanftially stationary when said bit and stem are reciprocated rapidly.

2. A percussion drill comprising a drill bit,. a drill stem attached directly to said drill bit, a hollow weight receiving said drill stem and freely movable therealong and supported thereby, said weight having an enlarged cavity formed therein, and a coil spring disposed within said cavity, encircling and supported by said drill stem at a point substantially below the upper end of said cavity against downward movement and so disposed with relation to said weight as to be compressed on the upstroke of the drill stem and to expand against said drill stem on the downstroke, said weight being of sufliciently greater mass than said bit and stem to maintain the weight substantially stationary when said bit and stem are reciprocated rapidly.

3. The drill of claim 2, wherein said drill stem is provided with a projecting member disposed medially of said cavity and said coil spring is disposed thereabove and is supported thereby, said drill also including a second coil spring encircling said drill stem and disposed within said cavity with its ends abutting the bottom of said cavity and said projecting member.

4. A percussion drill comprising a drill bit, a hollow stem directly connected to said drill bit, a coil spring supported within said stem and at the lower end thereof and extending longitudinally thereof, and a weight disposed within said stem, resting upon said spring and freely movable longitudinally of said stem, said weight being of sutficiently greater mass than said bit and stem to maintain the weight substantially stationary when said bit and stem are reciprocated rapidly, and a second coil spring disposed within said hollow stem above said weight and resting thereon, the upper end of said spring abutting the upper end of said stem.

5. A percussion drill comprising: a drill stem; a drill bit secured to the lower end of said stem; an elongated annular weight circumscribing and freely slidable over said drill stem, said weight being formed with a cage intermediate its ends; a coil spring disposed in said cage about said drill stem with its upper end in abutment with the upper end of said cage; and a stop member fixed to said drill stem adjacent the lower end of said spring and serving as a stop therefor.

References Cited in the file of this patent UNITED STATES PATENTS

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