US2863638A - Rotary drill string apparatus - Google Patents

Description

Dec. 9, 1958 H. W.,THORNBURG 2,863,638 ROTARY DRILL STRING APPARATUS V Original File'dAug. 14, 1953 5 Sheets-Sheet l COMPRESSOR HEREm' W. THoRNwRq,

IN VEN TOR.

ATTORNEQ.

H., w. THORNBURG 2,863,638

ROTARY DRILL STRING APPARATUS Original Fi] ed Aug. 14, 1955 Dec. 9, 1958 5 Sheets-Sheet 2 m U m .m T.. W T w R E H INVENTOR.

ATTORNEY.

H. w. THORNBURG ROTARY DRILL STRING APPARATUS original Filed Aug. 14, 195s Dec. 9, 1958 5 Sheets-Sheet 3 HERBERT WJRoRNsoRa,

ATTORNEY United States Patent ROTARY DRILL STRING APPARATUS `Herbert W.`Tfhornbiirg, South Milwaukee, Wis., assignor to Bucyrus-Erie Company, South Milwaukee, Wis., a corporation of Delaware 6 Claims. (Cl. Z55-19) This invention relates to well-drill equipment and more particularly to new and useful improvements 'in drillstring apparatus for rotary-type blast-hole drills.

This invention is a divisional of copending application Serial No. 374,364, iiled August 14, 1953, for Rotary Well Drill.

The principal objects of the invention are to provide an improved detachable rotary drill-string apparatus iu which:

(l) A tlexible coupling between the rotary driving unit and the drill pipe provides with limited transverse flexibility a direct positive torque drive and pull-down connection and at the Sametime a passage for compressed air supplied to the drill bit.

(2) The upper end of the drill pipe is automatically locked against rotation relative to the drive shaft responsive to the compressed .air supplied to the string.

(3) The drill-pipe joints will break before the joint between the drill pipe and rotary-driving unit, eliminating the need for tool wrenches to hold the driving unit-drill pipe joint while unscrewing of the drill-pipe joints during take-down of the drill string.

(4) The uppermost drill-pipe joint is self-tightening, and automatically locked against unscrewing. l

In addition to the principal objects above stated, a number of novel and useful details have been worked out which will be readily evident as the description progresses.

The invention consists in the lnovel parts and in the combination and arrangement thereof, which are defined in the appended claims, and of which one embodiment is exemplified in the accompanying drawings, which are hereinafter particularly described and explained.

Throughout the description the same reference-number is applied to the same member or to similar members.

Figure 1 is a side elevation, partly in section, showing the rotary-power unit, rotary-drive coupling and tool wrench on the rotary-drive coupling.

Figure 2 is a vertical section taken alongline 2--2 of Figure 3, showing the ilexible coupling connected to the drill pipe and showing the tool wrench engaged with the upper end of the drill pipe.

Figure 3 is a horizontal section, taken alongline 3 3 of Figure 2, showing the tool wrench which is associated with the rotary-drive coupling.

Figuref4 is an enlarged plan view of Figure 2, taken along line 4-4 of Figure 5, showing the upper split collar of the flexible coupling bolted in place, and in cross section, the lower resilient washer and interlocking teeth of the tlexible coupling in driving contact during clockwise rotation of the drive shaft.

Figure 5 is an enlarged Vertical section view taken along line 5-5 of Figure 4, showing the assembled elements of the exible coupling, and the interconnection between the uid conduits, plungermechanism and pawls which engage with the upper end of the drill'pipe section adjacent the rotary drive coupling.

Turning now to the gures, Figure 1 vshows the drill "ice string of the rotary-type blast-hole drill shown and described in my copending applications, Serial No. 374,364, tiled August 14, 1953, for Rotary Well Drill, and Serial No. 464,471, filed October 25, v1954, for Well Drill Pipe-Handling Apparatus, which are hereby incorporated by reference herein.

From Figure 1, it is seen thatframe 30, which is vertically movable with Vreference to the supporting fixed mast 14 (fully described in said lcopending applications), carries the rotary-drive machineryV for the drill-pipe l34 and thecoupling 33 and thatcoupling 33 provides not only a rotary-drive connection, but also a supporting connection, to the drill `pipe so that the drill .pipe can be raisedand lowered as well as rotated.l .Frame 30 is v-operatively connected to the rotary-'drill mast bypinions 36 meshing with a vertical rack on the mast (not shown), and-is raised and lowered under power of cables (not shown) reeved on shipper-shaft-drum 37 keyed to shippershaft 3S rotatably Amounted onframe 30, all of which is more particularly shown and described in my aforementioned copending applications.

`Drill pipe 34 is made `up of oneor more tubular drillpipe sections detachably connected one to another by threaded joints. A rotary drill `bit (not shown) vis thread- Ajoint connected to the lower-end of the lowermost drillpipe section. l

Reversible electric motor 31 is drivably connected, through reduction gears 97a, 97h, and 97C, to gear 98 which is splined toshaft 99 of rotary-drive unit 32.1 The lower end ofshaft 99 is connected bycoupling 33 to the upper end of the drill string.

Referring to Figures '1, r2, 4 and 5, theflexible coupling 33 will now be described.

Driving flange 33a is built integral with the lower end ofshaft 99 and is provided with a plurality of depending downwardly projectingteeth 33b (Figure 5) spaced near the periphery of saidflange 33a. A plurality lof corresponding upwardly projecting teeth 33C near the periphery of` the upper face ofsocket 33d register withteeth 33b onange 33a to provide torsional driving connection tosocket 33d. Theteeth 33e are held in interlocking engagement with -teeth '33b in the following manner.

Annularresilient washer 33g is fitted over vthe lower end ofshaft 99 and is spaced between the upper `face ofsocket 33d and the lower face ofange 33a. Annularresilient washer 33h is tted overshaft 99 adjacent the upper face ofange 33a. A splitannular collar 33e (Figure 4) is fitted adjacent the upper yface ofresilient washer 33h (Figure S).Cap screws 331 extend vertically downward through holes 33j, bored insplit collarI 33e, through enlarged holes 33k bored inange 33a to register with holes 33]',1and are threaded vertically downward intoteeth 33e atthreads 331 tapped in socket `33a! to securesplit collar 33e to said socket. By tighteningcap screws 331, splitcollar 33e andsocket 33d are rigidly connected,resilient washers 33g and 33h areplaced under compression, andteeth 33b and 33C vare interlocked, but are provided with some vertical spacing between the top surface of each tooth and the bottom surface of its corresponding notch due to the thickness ofresilient washers 33g and 33h. Splitcollar 33e and bolts 33j, which rigidly connect said collar andsocket 33d, take the tension in hoisting the drill line.

The lower portion ofsocket 33d (Figures l and 5) is threaded to make a threaded joint with. thetop drill pipe'fsection 34 atthreads 21 and 27, and carries a drill pipe gripping mechanism (hereinafter described) for locking said drill pipe section tosocket 33d.

Theresilient washers 33g and 33h provide a laterally and axially flexible coupling between therotary drive unit 32 and thedrill pipe 34, so that the head of the 3 drill string may wobble slightly, and vibrations in the drill string are absorbed instead of being transmitted directly into the Arotary drive mechanism. Whenever there is a lateral deflection ofdrill string 34, theresilient washers 33g and 33h permit the joint to bend, but engagement betweenteeth 33b and 33C is retained for applying torque to the drill string. In this respect, the coupling is similar to a universal joint. If the drill string, for example, is laterally dellected to the left in Figure 5,socket 33d will pivot about the-center ofcentral core 102, andresilient washer 33h will be further compressed betweenange 33avand split collar 33e on the right side of the coupling and said washer will expand on the opposite side of the coupling. Meanwhile `resilient washer 33g on the right side of the coupling will expand, and on the opposite side of the coupling said washer will be further compressed betweensocket 33d andange 33a.Resilient washer 33g will absorb any shock in the coupling created by vertical bouncing of the drill string, and also acts as an air-tight seal betweencentral core 102 of thedrive shaft 99 and central annular chamber 102a. -Chamber 102a is bored axially from the bottom ofsocket 33d and narrows in diameter near the top of said socket to register withcentral core 102.Resilient washer 33h will similarly absorb any shock in the coupling in a downward direction caused by downward movement of the drill string relative to the coupling.

Although these resilient washers provide a limited ilexibility under `compression and lateral forces, a rotary drive coupling is always maintained betweenteeth 33b and 33C. The fact that there is clearance between the sides of the teeth opposite their sides that are in driving engagement, and the further fact that there is Vertical clearance between the tips ofteeth 33b and 33C and the respective bottom surface of their corresponding notches n allow the teeth limited lateral and vertical shifting movement relative to each other.

Flexible pressure-fluid conduit 100 (Figure l) extends from a compressor (not shown) to pressure Huid-tight seallng ring 101 on rotary-drive unit 32. The upper end of central core 102 (see Figures 2 and 5), extending axlally ofshaft 99, registers with conduit 100 (Figure 1) and makes a fluid-tight connection therewith at pressure fluid-tight sealing ring 101.Central core 102 extends from pressure fluid-tight sealing ring 101 throughcoupllng 33 and makes a fluid connection withcentral core 103 ofdrill pipe 34.

Referring to Figures 2, 3 and 5, a drill-pipe gripping mechanlsm consisting of twopawls 151 mounted on either side of the lower end of rotary-drive coupling socket 33d to pivot abouthorizontal pins 153 is employed to engage the upper end of the uppermost drill-pipe sectlon just below its connection to the rotary-drive coupllng 33.

Each pawl 151 s actuated by the downward extension of ltscorresponding plunger 154 bearing against the upper horizontal surface of said pawl outwardly of the center of its horizontal pin 153 (Figure 5) to rotate said pawl inwardly at its lower end and engagenotches 155 1n the upper end of the top section ofdrill pipe 34, each of said notches being formed to receive itscorresponding pawl 151 to permit only right-hand or clockwise rotation of the rotary drive coupling relative to said drill pipe (Figure 3).

Eachplunger 154 tits into acorresponding chamber 158 formed on diametrically opposite sides ofsocket 33d. Port 157, which is bored vertically from the upper end of eachchamber 158, makes a fluid lconnection between the upper end ofchamber 158 and atransverse passage 156,

said passage being bored radially near the upper end ofsocket 33d and is sealed by plugs 162 (see Figures 4 and 5 Passage 156 opens into central annularchamber 102a'in socket 33d. Fitted aboveplunger 154 inchamber `158 is an air seal 154:1 to prevent leakageof airpast plunger 154. Eachplunger 154 is` actuated by compressed ving dirt and rock chips from the drill hole.

air which passes from supply conduit intocentral core 102 ofcoupling 33, then throughtransverse passages 156 andport 157 intochamber 158 in which theplunger 154 is seated.Pawls 151 are normally held in their outward position (dotted outline in Figure 5) by coil springs 159 (Figures 3 and 5 Eachrespective plunger 154 rests against the upper outer horizontal edge of its matchingpawl 151. The vertical line of contact betweenplunger 154 andpawl 151 is outward of the center of rotation ofhorizontal pin 153, which is the pivot point ofpawl 151. Therefore, wheneverplunger 158 is actuated downward by compressed air, eachpawl 151 is rotated inwardly to engage the topdrill pipe section 34 at anotch 155. During drilling compressed air or other iluid is forced throughcentral core 102,central core 103 ofdrill pipe 34 and out through theb ottorn of the drill bit into the drill hole. This is a conventional means ofscaveng- The fluid pressure used to clear material from the drill hole is also used to actuate and seatpawls 151 of the wrench.Pawls 151 are automatically actuated byplunger 154 to engage the drill pipe as soon as fluid pressure is lbuilt up in the core of the drill string. When so engaged the pawls will, due to the notches, permit right-hand or clockwise (Fig. 3) rotation of the rotary drive coupling to screw the coupling threads onto the threads of the upper drill pipe section, but will lock the rotary driving coupling against unscrewing from the drill pipe counterclockwise relative to the drill pipe when the rotary drive rotates the drill pipe in a left-hand or counterclockwise direction of rotation. This permits right-hand threads 27 on the upper end ofdrill pipe 34 to screw intocorresponding threads 21 ofcoupling 33 and tighten the joint betweencoupling 33 anddrill pipe 34 whilepawls 151 are engaged, but preventsthreads 21 and 27 from unscrewing, and the joint from loosening during takedown of the drill string.

During drilling and make-up of the drill string, the rotary drive rotates the drill string in the right-hand or clockwise direction (Fig. 3). During take-down of the drill string, the section of drill pipe adjacent the uppermost drill-pipe section is held stationary by a tool wrench (shown in Fig. 22 of my copending application, Serial No. 464,471, tiled October 25, 1954), and the rotary drive rotates in the left-hand or counterclockwise direction, unscrewing the joint between the stationary drillpipe section and the uppermost drill-pipe section.

When air pressure is shut off, springs 159 betweencoupling 33d andcollar 160 ofpins 153 bias eachpawl 151, so thatpawls 151 will normally return to disengaged position (shown in phantom lines in Fig. 2), and thereby biasplungers 154 to return to their retracted position in chamber 158 (see Fig. 5).

A further feature of the invention is thatbevel face 25 at the lower end of each drill-pipe section 34 (Figure 2), makeshorizontal shoulder 26, at said lower end ofdrill pipe 34, smaller in diameter thanshoulder 22 at the upper end of each drill-pipe section 34. -Shoulder 22a oncoupling 33 is of thesame diameteras shoulder 22 on the upper end of drill-pipe section 34. Accordingly, the contact betweenshoulders 22 and 26 will have less friction resistance to unscrewing than the Contact betweenshoulders 22 and 22a, and hence the lower thread-joint will normally break before the upper thread-joint atcoupling 33. Should the next lower joint become stuck or frozen and thus fail to break lirst, the drill pipe gripping mechanism is available for standby use to lock the upper joint against unscrewing. By turning on the air supply,

vwhich is fed through -central core 102 (Fig. 2), pawls described, itis to beeunderstoo'd that the invention is not to be limited to the specific form or arrangement of parts as herein described and shown, or specifically covered by the claims.

I claim:

1. In a detachable torque-drive coupling device for coupling a rotary drive power means and the uppermost tubular drill-pipe section of a rotary drill string for transmitting rotation thereto and absorbing lateral and axial vibrations, the combination of: a rotary drive member associated with said rotary drive power means; a driven member having a detachable rotary-drive connection with the upper end of said uppermost drill-pipe section; interlock means providing a loose laterally ilexible rotarydrive connection between said driving member and said driven member; a first pair of axially-opposed lateral bearing surfaces located one on and adjacent the lower end and the other on and adjacent the upper end of the driving and driven members respectively; first resilient means interposed between said first pair of bearing surfaces, said first resilient means being subjected to axial compression by said first pair of bearing surfaces when said driving and driven members are in mutual compression; a coupling member detachably connected in axiallyxed relation to one of said driven and driving members; a second pair of axially-opposed lateral bearing surfaces located one on said coupling member and the other on the other of said driven and driving members; second resilient means interposed between said second pair of bearing surfaces, said second resilient means being subjected to compression by said second pair of bearing surfaces when said driving and driven members are in mutual axial tension; a longitudinal hollow core for the passage of pressure fluid extending longitudinally through said driving member, said driven member, and said coupling member, to said uppermost drill-pipe section; said first resilient means forming a seal between the driving and driven members to prevent the escape of pressure fluid from said longitudinal hollow core.

2. A torque-drive coupling device according to claim 1, further characterized by having a drill-pipe gripping mechanism mounted on said driven member, and pressure fluid responsive actuating means having a pressure uid connection with said longitudinal hollow core and operatively connected to said drill-pipe gripping mechanism to automatically actuate said mechanism by pressure fluid in said hollow core to engage the uppermost drill-pipe section and lock it against rotational displacement in one direction relative to said driven member.

3. A torque-drive coupling device according toclaim 2, further characterized by the fact that the drill-pipe mechanism includes a pair of pawls adapted to engage cooperating notches on said uppermost drill-pipe section.

4. A torque-drive coupling device according toclaim 3, further characterized by having resilient means operatively connected to said pair of pawls biasing said pawls to normally disengage the uppermost drill-pipe section.

5. In a detachable torque-drive coupling device for coupling a rotary drive power means and the uppermost tubular drill-pipe section of a rotary drill string, for transmitting rotation and vertical movement thereto, the

combination of: a rotary drive member associated with said rotary drive power means; a driven member having a disengageable rotary-drive connection with the upper end of said uppermost drill-pipe section; a rotary-drive connection between said driving member and said driven member; a longitudinal hollow core for the passage of pressure uid longitudinally through said driving member and said driven member to said uppermost drill-pipe section; a drill-pipe gripping mechanism mounted on one of said members, and pressure-fluid responsive actuating means having a pressure-fluid connection with said hollow core and operatively connected to said drill-pipe gripping mechanism to automatically actuate said mechanism by pressure iluid in said hollow core to engage the uppermost drill-pipe section and lock it against rotational displacement in one direction relative to said driven member.

6. In a detachable torque-drive coupling device for coupling a rotary drive power means and a rotary drill string for transmitting rotational and Vertical movement thereto, the combination of: a rotary drive member associated with said rotary drive power means; a driven member; a rotary drive connection between said drive member and said driven member; a drill-pipe section adapted to form the uppermost drill-pipe section of said rotary drill string; said uppermost drill-pipe section having threads at its upper and lower ends, one an inner thread and the other an outer thread, for threaded joint connections to the rotary drive member and the next lower drill-pipe section of the rotary drill string, and having a cooperating friction contact surface adjacent each of said upper and lower threads adapted to have cooperating contact with opposing friction surfaces on said rotary drive member and said next lower drill-pipe section; said rotary driven member having a thread for said threaded joint connection with the uppermost drill-pipe section, and being engageable and disengageable therewith by rotation of said driven member about its axis relative to said uppermost drill-pipe section; and a cooperating friction contact surface at the lower end of the driven member adjacent the threaded joint connection between the driven member and the uppermost drill-pipe section having cooperating friction contact with the cooperating friction contact surface at the upper end of the uppermost drill-pipe section when the last-mentioned threaded joint connection is substantially engaged; the area of such cooperating friction contact being greater than the area of the cooperating friction contact surface at the lower end of the uppermost drill-pipe section.

References Cited in the le of this patent UNITED STATES PATENTS 1,728,111 Elms et al Sept. 10, 1929 1,857,528 Cantell May 10, 1932 1,960,688 Archer May 29, 1934 1,983,545 Johnson Dec. 11, 1934 2,439,751 Olsen 1 Apr. 13, 1948 2,620,165 Crickmer Dec. 2, 1952 2,765,147 Vertson Oct. 2, 1956

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