US2245960A - Rotary well drilling apparatus - Google Patents

Description

G. K.' CLAIRE ROTARY WELL DRILLING A PPARATUS June 17, 1941.

Filed March io, 1959 s 'Smeets-sheet 1v Gaf /f 62511K @www `une 17, 1941. G, K CLAIRE V 2,245,960

ROTARY WELL DRILLNG APPARATUS Filed March 1o, 1959 s sheets-sheet 2' v June 17, 1941.. v G. K. CLAIRE v2,245,960

' ROTARY WELL DRILLING APPAATUs Filed March 1o, 1939 :s sheets-sheet s Vthreaded connections Patented June 17, 1941 Guy K. claire, mum-g mus,

Calif., assignor of one-third to Arthur L. Armentrout, one-third to Elwin B. Hail, and one-third to Virgil P. Baker, f

i all of Los Angeles, Calif.

Application Maren 1o, 1939, serial No. 260,911l

18 Claims.

This invention relates to well drilling equipment and relates more particularly to a rotary table or rotary` for use in the rotary method of Well drilling. A general object of this invention is to provide a practical effective and improved rotary table for rotating the ,well strings and for performing the other functions of typical rotary tables and for making up and breaking down the drilling strings and other sectional well strings.

In the rotary method of well drilling a -power driven rotary table is provided in the derrick to carry the bushings, slips and other devices for ing strings, the casing strings, etc. A weil string such as a rotary drilling string is made up of a' plurality of stands of pipe connected by threaded vcouplings and during the drilling operation a vpolygonal or fiuted kelly is connected in the upper portion of the string to operate through the rotary table. The kelly is engaged by a correspondingly to provide a rotary transmitting drivebetween the table and the drilling string. In making up and breaking down a rotary drilling string it is the general practice to`support the string in the table by means oi' slips and to 'turn the uppermost stand of pipe while securing the lower portion of the string against rotation. One set of tongs is usually engaged about a section of the tool joint at the table and another set of tongs is engaged about the other' section of the tool Joint. The last named set of tongs is usually operated by aline handled by a cathead oi the draw works. The operation of the tongs and the` lines is a time consuming operation and is accompanied by considerable danger to the workmen and equipment.' Furthermore, in making up the by tongs and a jerk line it is difilcult, if not impossible, to gauge the tor rsion applied to the .connections and in many cases the threads of the pipe connections are galled or strained 'endangering the entire weil string and shortening 'the life o f the joints..

Rotary tables known as make and break rob' taries have been proposed to facilitate the mak ing up and breaking down of the well strings.

' These make and break rotary vtables yusually ein# body inner and outer independently rotatable table parts with means on the inner table parir to hold the pipe against turning and means on the outer table part to the main inner table part,

is utilized to ro- (Cl. Z55-23) body practical or supporting and engaging the tool-carrying drillshaped bushing in the rotary table engine' throughout the down the well strings. This e of the main power means of the rotary table to drive the outer table part is very respects. For example, it necessitates a special complicated means for connecting and disengag-v ing the inner and outer parts of the table and requires the continuous operation of the rotary erations. Furthermore, the make and break rotary tables that have been proposed do not emy effective means for gauging the torque applied to well strings. brake means be utilized to ,hold one section of the table against turning-during the making up of 'the'threaded joints. which brake ymeans will release when a given torque Ais applied to the threaded connections y Such brake means are impractical, are not dependable. and do not assure the uniform appli tion of torque to the many joints of the dril ng string.

Another object oi' this invention is to provide a rotary or a rotary "table operable to makeup down sectional well or thread together the joints of a rotary well drilling string under a given uniform torque or rotational force to assure tion of the string sections and to prevent galling and straining of the threads.

Another object of this invention is to provide a rotary table operable to make up and break strings that embodies an automatic torque governed drive or power means for rotating one part of the table, which power .means may be set or conditioned to make up the Joints underl a tional force.

, Another object of this invention is to provide given or selected uniform rotaa' rotary table of the character mentioned emkbodying a ring'or outer part rotatable relative to the inner table part to make up and break connections of the well strings and a separate drive and power means for .rotating the said outer part. The improved roturn the upper stand of pipe. In these sc-called make and break rotary- 'up Aand breaking 55 tary table of the present invention embodies a drive of suitable or customary form for rotating the main inner table part anda'separate drive and power means for operating the outer table part to break and make the threaded joints of the wellfstrings.

Another obiect of this invention is to provide a rotary table of' the lcharacter mentioned in which the drivefor the outer table part may be utilized as an emergency drive or special drive for rotating the entire table and thisy drive is torque controlled thereby adapting the rotary ta'- unsatisfactory in many making and breaking opg-A the threaded connections of the It has been proposed that friction' the dependable connec- `operative positions.

ble for use in special drilling operations, etc. where a torque controlled rotation of the well string is necessary. The drive for the outer table part is very important as it assures the continued operation of the drilling string in the event the regular drive fails and, therefore, makes it unnecessary to provide an expensive auxiliary drive means for the table.

Anpther object of this invention is to provide arotary table of the character mentioned embodying novel, dependable and safe means for supporting the pipe engaging tongs on the -base and outer table part for easy manual movement between their operative positions about the pipe and retracted positions clear of the rotary table bushings. The tong supporting means of the present invention are such that the tongs may be retracted to 4positions where they do not interfere with the drilling operations at the rotary table and are such that the tongs may be handled with little or no danger to the workmen.

Another object of this invention is to provide a rotary table of the character mentioned in which the .drive for the outer table part is fully controlled by simple, manual operations of a switch and brake located at a convenient station.

A further object of this invention is to provide a rotary table of the character referred to including novel practical and effective means for supporting the rotatable outer table part.

A still further object of this invention is to provide a rotary table of the character mentioned embodying means for visibly indicating the rotational force being applied while making up the joints or connections'.

The various objects and features of my invention will be fully understood from the following detailed descriptionof a typical preferred form and application of the invention, throughout which description reference is made to the accompanying drawings, in which:

Fig. 1 is a top or plan view of the rotary table of the present invention showing the tongs in the Fig. 2 is an enlarged fragmentary vertical detailed sectional view taken substantially as indicated by line 2 2 on Fig. 1.

Fig; 3 is an enlarged fragmentary vertical detailed sectional view taken as indicated by line 3 3 on Fig. 2. Fig. 4 is an enlarged fragmentary vertical detailed sectional view taken substantially as indicated by line 4 4 on Fig. 1. Fig. 5 is an enlarged fragmentary vertical detailed sectional view taken as indicated by line 5 3 on Fig. 1 with the motor, reduction gearing and other parts in side elevation. Fig. 6 is an enlarged vertical detailed sectional view taken substantially as indicated by line 6 6 on Fig. 5 with the motor in elevation. Fig. '1 is an enlarged fragmentary vertical detailed sectional view taken. as indicated by line 1 1 on Fig. 5.

may be said to comprise, generally, a base I0 to be mounted at the upper end of the well, an inner table part rotatably supported on the base The base l0 is provided to support the various operating elements of the apparatus and is support the inner part II.

Fig. 8 is an enlarged fragmentary vertical detailed sectional view taken as indicated by line 3 8 on Fig. 5 with the brake means in elevation. Fig. 9 is a'fragmentary side elevation of the brake means taken as indicated by line 9 9 on Fig. 8.

Fig. 10 is a wiring diagram of the circuits em- 'I'he improved rotary table of this .invention adapted to be suitably mounted on the floor of the well derrick. The base I0 is provided with a generally rectangular lower part I6 to be secured to the supports of the table. The base I 0 further includes an upstandingannular inner wall I1 surrounding or defining the central vertical opening I9 of the base and an upstanding outer wall I9 spaced some distance from the wall I1. Webs 20 extend between and connect the lower portions of the spaced walls I1 and I9. An upstanding intermediate wall 2| is spaced between the inner and outer walls-I1 and I9 and is somewhat higher than the inner wall I1. An annular flange 22 projects upwardly and outwardly from the outer wall I9 to support the outer part I3 of the rotary table, as will be later described. A lateral or radial tubular extension 23 is provided at one side of the base I0 to receive certain parts oi' the drive I2 for the inner table part I I. The extension 23 extends below the `ange 22 and its opening 24 continues inwardly through the outer base wall I9.

The inner table part is provided to' carry the bushings, slips, etc. employed in the various well drilling operations. The inner part of the rotary table is an annular member or structure arranged in the base I0. In the preferred construction the inner table part includes a main upper portion 25 overlying the inner wall `II of the base I IJ and the channel or space between the walls I1 and 2|. A tubular depending flange 23 on the upper portion 25 extends downwardly through the opening 8 in overlapping relation to the inner wall I1 of the base I0. A suitable anti-friction bearing 21 is seated in the base I0 between the walls |1 and 2| to rotatably The bearing 21 is seated against shoulders on the portion 25 and the wall 2| to take lateral thrusts as well as the vertical loads. An apron ring 28 is threaded to the lower portion of the flange 26 and has an annular upwardly facing channel 29. A bearing 30 is seated in the channel 29 to engage upwardly against a base web 20 for the transmission of upwardV and lateral thrusts from the inner table part to the base I0. A suitable lubricant is provided in the channels of the base I0 carrying the bearings 21 and 30 and the adjacent portions of thebase I0 and the inner part I| mesh or overlap to seal ofi.' the bearing carryingv channels.

The inner element or part of the rotary table is annular, being provided with a central vertical opening 3| for receiving the bushing elements. The upper portion of the opening 3| is polygonal while the portion of the opening 3| extending through the flange 26 may be cylin'- drical. An upwardly facing shoulder 32 occurs on the wall of the opening 3| between its cylindrical and polygonal portions. A master bushing 33 is arranged in the opening 3| to seat on the shoulder 32. The upper portion of the bushing 33 is shaped to conform to the polygonal part of the opening 3| so that the bushing turns with support the shaft 2,245,960 The opening in the master the table part II. bushing 33 has a polygonal upper part for receiving correspondingly shaped portions of kelly bushings, etc. The lower portion of the bushing opening 34 is tapered or conical to receive slips 35. As illustrated in the drawings the slips 35 may be seated in the opening 34 to grip and support a well string S.

The drive means I2 for rotating the inner ta ble part II is provided to drive the table part II during the regular drilling operations, etc. The

drive means I2v includes a ring gear 35 secured to the inner table part I I. The ringl gear 36 may be integral with the main upper portion 25 of the table part I I or may be -a separately formed annular element rigidly engaged about the portion 25 as illustrated in the drawings. `The upper surface of the ring gear with the topsurface of the portion 25 and the master bushing 33. 'I'he lower side of the ring gear 36 has an annular series of bevel gear teeth 31. An annular groove 38 in the under side of the gear 36 receives a reduced upper edge portion of the intermediate base wall 2| to provide a seal.

The drive means I2 for the inner table part II further includes a substantially horizontal shaft 39 extending inwardly through the opening 2l in the table extension 23. Suitable bearings 40 39 for free rotation. 'Ihe shaft 39 may be driven by any suitable power means. In the case illustrated a sprocket 32 is keyed to the projecting outer portion of the shaft 39 and a chain 43 operated by the drilling engine (not shown) meshes with the sprocket B2 to rotate the shaft 39. A bevel pinion t4 is fixed or keyed to the inner end portion of the shaft 39 to mesh with the teeth 3l of the ring gear 38. Suitable means controlled by manual levers 35 are lprovided in the extension 23 to lock the shaft 39 and theinner table part II against rotation. The details of this shaft holding means are not shown as they are well known to those skilled in the art. .The base I has a chamber 99 for carrying a bath of lubricant for the pinion M and the other operating parts. The upper portion of the outer base wall I9 is received in an annular groove 3l in the 'ring gear 36 to form a seal between the ring gear and the base. The inner the means I2 just` described is, of course, controlled by the driller in the usual manner.

The outer table part I3' surrounds the inner part II and serves to carry one unit oi the tong supporting means I5. In accordance with the invention the outer table part I3 is in the nature of a ring surrounding the ring gear 33 with some clearance. It is preferred to arrange the tablepart I3 so that its upper surface is in substantially the same plane as the top surfaces of the inner part II and the ring gear 3B. The outer table part I3 overlies the base flange 22 and is supported on bearing means 48. The bearing means 43 may comprise a series of ballsl cooperating with an nul .-.r races'in the flange 22 and an annular section 59 fixed to the outer table part I3. The section 49 may be pressed into the part I3 or otherwise fixed to it. The base flange 22 is designed to carry a lubricant bath for the bearing meansti. The upper edge portion of the flange 22 is received in a groove 59 -in the table part I3 to form a seal. Means is provided to prevent upward movement of the outer table part I3. A plurality of circumferentially spaced `posts 5I is secured to the outer base Wall I9. The posts theouter table part I3.

36 is preferably flush 5I extend upwardly through openings in the flange 22 and carry rotatable rollers 52 cooperating with a track part I3. The rollers 52 engaging in the track 53 prevent tilting and upward movement of the outer table part I3. A ring 54 is provided to close the annular space between the ring gear 35 and The ring 54 may be secured to the posts 5I by screws 56B. In the preferred construction the ring 54 is designed to partially overlie the outer table part I3 to more effectively prevent the entrance of water, dirt, etc. to the flange 22.

The means )I4 for driving or rotating the outer table part I3 is an important feature of the invention. The means I4 is operable to rotate the outer table part I3 relative to the inner table part II in both the 'righthand and the lefthand directions. In accordance with the invention the means I4 embodies an automatic torque control whereby the rotary table is operable to make up the numerous joints of a wellstring underva uniform rotational force of a selected intensity.

The drive means Id includes a supporting bracket 55 projecting outwardly or radially from 'I the outer wall I9 of the base I9 (see Fig. 5). The bracket-55 is suitably fixed to the` base wall I9 and preferably projects outwardly in spaced diverging relation to the base extension 23. The

power generating unit of the drive means I4 is mounted on ,the bracket 55. erating unit of the means the nature of a reversible electric motor 56 of a suitable rating, it being apparent that other^ employed 4as lli. The

equivalent prime movers may be the power generating unit of the means ymotor 56 is preferably of an explosion-proof table part I'I driven byv v the flange 22 by anti-friction In the preferred construction the motor 56 is arranged so that its shaft 5l is radial relative to the common axis of rotation of the table parts II and I3. A suitable coupling 58 connects type.

`the inner end of the motor shaft 51 with the shaft 59e of a geared speed reduction unit 60. The speed reduction unit 60 is suitably fixed to the bracket and the inner end of its shaft 59 projects inwardly under the `table part I3. In accordance with the invention the motor 56 is supported to swing or turn on its axis under the influence of torque or driving load. A cradle 5I is fixed to the under side of the motor 56 and has inner and outer arms 62 and 63 projecting upwardly atv the opposite ends of the motor. A bearing post 53 projects upwardly at the outer end of the bracket 55 and has a bearing 65 rotatably supporting the outer end of the motor shaft 51. The arm bearing 63' adjacent the bearing 65 assisting in 53 in the section 49 of the table.

The power genf I4 is preferably in 4 32 ofthe cradle 6I has a.

supporting the motor shaft 51. The inner cradle arm 33 has a similar bearing 6l`receiving the shaft 59a of the speed reduction unit 60. It will be seen that the cradle 6I assists in supporting the motor 56 and vis swingable or turnable. with the motor. The cradle 6I forms i ment of the lautomatic torque control, as will be subsequently described.

The drive means I4 further includes an annular series of bevel gear teeth 68 on the under side of the outer table part I3. A pinion 39 is keyed portion' of the shait'59 and meshes withv the teeth 58. The flange 22 of the base I0 is formed to receive the pinion 59 and to contain a lubricant bath at the pinion. It will be seen that the motor 53 is operable to rotate the outer table part I3 through the medium of a movable ele- The automatic torque control for the motor 56 includes a yielding means resisting turning of the motor resulting from a torque load on the motor when the same is rotating the table part I3 in a righthand direction in making up the connectlons of the string S. The means for resisting swinging or turning of the motor 56 may include a web 1I on the cradle and a helical spring 15 arranged against the web 1I. A pin 16 is provided on the web 1| to hold the spring 15 against displacement. The outer end of the spring 15 is arranged against a part to be later described and the spring serves to resist turning or swinging of the motor 56.

In referring to Fig. of the drawings it will be seen that the energizing circuit of the motor 56 includes incoming power leads 18 extending from a suitable source of electrical energy. The leads 18 extend to a reversing switch 19 for controlling the reversible motor 56. 'Ihe switch 19 may be of any suitable form of remotely controlled reversing switch. For example, it may be a magnetic reversing switch of any well known type. Leads 89 extend from theswitch 19 to the motor 56 and the reversing switch 19 has a control circuit 8|. A manual switch 82 is connected in the circuit 8| and is adapted to be operated to cause forward and reverse energizetion of the motor 56 and de-energization of the motor. The switch 82 may be a push button switch having a forward button 83. a stop button 84 and a reversing button 85. The manual switch 82 is preferably located for convenient operation by the operator or driller. In practice I prefer to mount the switch 82 on a post 86 projecting upwardly from the base portion I6 adjacent the base extension 23. I

Visible indicating means is provided to indicate ythe rotational force or torque being appliedv in making up the couplings and in performing other operations. This means includes a pressure gauge 10, that may be mounted on the post 86. The gauge 10 is calibrated in thousands of foot-pounds. A pipe or conductor 12 leads from the gauge to a. diaphragm 13 supported by a bracket 14 on the bracket 55. The diaphragm 13 may bel of the Sylphon type or of of the type shown. The outer end of the above described spring 15 engages a head 11 on the diaphragm 13. When the cradle 6I swings under the motor torque the spring 15 transmits force to the diaphragm 13 and the gauge 10 indicates the torque force being applied to the coupling or work. The diaphragm head 11 is shaped to retainthe outer part of the spring 15. The operator observing the gauge 10 may operate the switch 82 to make up the couplings at any selected torque force or rotational force.

The automa-tic torque control of the drive I4 further includes a stop switch or limiting switch 81 connected in the common lead 88 of the control circuit 8| between the switch 82 and the reversing switch: 19. The limiting switch 81 is mounted on the bracket 55 for adjustment toward and away from the web 1I and has a projecting pivoted or turnable operating part 89. The switch 81 is positioned so that its operating part 89 is engaged and moved by the web 1I of the cradle 6I when the motor 56 swings under the influence of a load of a given intensity. As illustra-ted in the drawings, the switch 81 has a pin |30 shiftable in a slot I3I in the bracket 55. A screw |32 is threaded through an opening in a lug |33 on the bracket 55 and cooperates with the switch 81 to adjust the same relative to the cradle web 1I. The screw |32 may be manipulated to adjust the switch 81 to be operated by the web 1I when any selected torque or force is applied to the work.

A nger |35 on the switch 81 cooperates with a scale |36 on the bracket 55 to indicate the position of the switch in terms of the foot-pounds of torque on the work required to cause operation of the switch. The switch 81 may be spring urged to the closed position and actuation of the part 89 by the web 1I effects opening of the switch 81. The stop button 84 of the switch 82 and the limiting switch 81 are both operable to open the circuits to the coils or magnetic means of the reversing switch 19 to effect deenergization of the motor 56. A lock nut |31 may be employed to lock the adjusting screw |32 in any selected position.

It may be desired to control the drive means I4 by the torque load to effect de-energization of the motor 56 when the table part I3 is being rotated in a lefthand direction to make up the connections in a lefthand drilling string, or the like.4 It will be apparent that if this is desired a switch similar to the switch 81 may be arranged to be actuated by the web 1I when the motor 56 swings under a lefthand torque of a given intensity to effect the deenergization of the motor 56. In the case, illustrated, however,.a stop 90 is provided on the bracket 55 to limit or prevent swinging of the motor 56 when the outer part I3 is being driven in a lefthand direction. The parts may be related so that the spring 15 described above normally holds the motor 56 in a position where the cradle web 1I engages against the stop 90.

It is preferred to provide brake means to stop turning of the oute'r table part I3 to facilitate the positioning of the tong supporting unit carried by the outer table part. The brake means illustrated in the drawings includes a drum 9| connected with the motor shaft 51. 'I'he drum 9| may be connected with the coupling58. A brake band 92 carrying a suitable friction material surrounds the drum 9| and is supported intermediate its ends by an adjustable anchor 93. The anchor 93 may be carried by a post 94 on the bracket 55. A lug 95 projects from an end oi' the brake band 92 and a spring 96 acts on the lug 95 to hold the brake band 92 in the released condition. A shaft 91 is turnably supported by the post 94 and a double-ended lever 98 is fixed to the shaft 91. A pivot 99 connects one end of the lever 98 with the other end of the brake band 92. A screw |00 is pivotally connected with the other arm of the lever 98' and extends through the spring 96 to the lug 95 of the brake band 92. A nut IOI on the screw |00 engages lug 95 to actuate the same upon turning of the lever 98.

A suitable brake operating linkage |02 is connected with a lever |03 fixed on the shaft 91. The linkage |02 extends to a point adjacent the post 86 carrying the manual switch 82 and is there provided with a pedal |03. The pedal |03 is conveniently operable by the operator controlling the switch 86. Upon depression of the pedal I 03 the shaft 91 is turned to tighten the brake band 92 on the brake drum 9| and thus stop rotation of the outer table part I3. By appropriate operation of the switch 82 and the brake pedal |03, the outer table part I3 may be turned to any selected rotative position.

/The tong supporting means I5 is provided to support a pair of tongs T for quick easy engagement with the string S above and below the joint or connection to be threaded or unthreaded. One unit of the tong supporting means I5 is xed to the base I vand the other unit oi the means I is carried by the outer table part |3. Thetong supporting unit of the means I5 on the base I0 includes 'a vertical post |04 removably secured to the base wall I9 and extending upwardly through an opening |05 in the ring 54. The post |04 may be secured to the wall I9 by any suitable quick connection means. For example, its lower end maybe removably held in a socket |30 on the wall I9 by a screw I3I. The unit of the tong supporting 'means |5 on the outer table part I3 includes a similar post |06 having. a foot |01 bolted to the part I3.` The post |06 is considerably taller than the post wl but is otherwise of the same design. Stems |08 are shiftable and turnable in vertical openings III provided in the posts IM and |06 and the stems are provided at their upperv ends with heads |09. Springs I I0 are arranged under compression between the lower ends of the stems |00 1 and the bottoms ofthe openings I The springs ||0 counterbalance or partially counterbalance the stems |08 and the parts carried thereby. The stems |08 may be locked or secured in the ad- .justed positions by clamp screws I I2. The heads may remain stationary. At this time the heads l. |09' and thearms II4 may be in retracted posi- |09 are provided with horizontal openings ||3 to receivetong carrying levers or arms IId.

The arms |I4 `are shiftable and turnable in the openings ||3 and project inwardly toward the string S when in the active positions. The tongs T are suitably secured to the inner ends of the arms Hd. Slots H5 are provided in the heads |09 and the arms lIi have keys il@ adapted to engage in the slots H5 to hold the arms against turning. By shifting the arms Hd inwardly toward the center of the table their keys I6 may be disengaged from the slots I i5 wherei uponthe arms may be reversed or turned 180 to invert the tongs T for right and lefthand operation. Stop heads H55 are provided on the arms il to limit this inward shifting of' the arms and to prevent disengagement of the arms from the heads |09. Springs Hte may be arranged under compression between the heads ii and shoulders ||1 to urge the arms ||i outwardly so that their keys IIB remain in cooperation with the slots |I5 during operation of the tongs T. The posts |00 and |06 are arranged to clear or pass one another during rotation of kthe ta ble'part I3. The head |09 andthe arm Hd of the unit carried by the table part i3 pass :freely over the head |09 and arm IId oi the tong supporting unit on the base Ill. When the tongs T are not in use the heads |09 may be turned to positions'where the arms Hd and the tongs T do not interfere with operations. at the rotary table.

Means is provided for connecting the inner and outer table parts I| and i3 for simultaneous rotation when it is desired to employ the torque controlleddrive means I@ in the voperation. oi well tools.- The means for connecting the inner and outer table parts and i3 may comprise bars H8 provided at their opposite ends with lugs IIB. The lugs H5 are adapted to engage in suitable openings IZ and |Z| in the tops of the table parts |I and I3, respectively, whereby the bars ||3 serve to connect the two table parte II and`fI3.

When the drilling string S is beingrotated to I. 5 operate a drilling tool, or the like. the inner table part -I| is rotated by the drive means I2 in the usual manner and the outer table part I3 tions where the tongs T are entirely clear of the inner table part II and the bushings carried.

thereby. When the drilling string S is being assembled or made up the slips 35 are employed asl illustrated in Fig. 4 of the drawings to support the lower portion of the string S on the lnner table part I I. The adjusting screw |32 may be set so that the mechanism `will make Aup the connections under any selected torque. The heads |09 andv the arms II4 are brought' to positions such as illustrated in Figs. 1 and 4 oi the drawings where the tongs T may engage about the upper and lower sections of the tool joint section or connection C being made up. The tongs T are suppotedin such a manner that they may be easily vand quickly arranged in the operative positions about the parts of the coupling C. The tongs T are supported by the arms |I4 and it is unnecessary to employ lines, cables, etc. to suspend and operate the tongs. When the tongs T have been properly engaged about the upper and lower sections of the connection C the forward button B3 of the manual switch 8'2 may be depressed to Aenergize the motor 5E. The motor 56 drives or rotates the outer table part 3 in a forward or righthand direction and the tong T carried lby the outer table part is thus rotated relative to the lower tong T supported by the stationary base I0. Prior to the connection of the tongs T with the coupling C the threadsof the coupling may have been manually started or mated. The rotation of the outer table part i3 and its tongs T by the drive IIi is continued until the threads of the connection or coupling C tighten. This tightening down of the threads of the coupling C .of course increases the torque or load on the motor 56 and this increased load results in swinging of the motor 56.

When the threads of the coupling C have been tightened under a given rotational force the web 'lI engages and operates the part 89 of the switch 81 to open the switch and thus cause cle-energization of the motor 56. Thus the tightening of the coupling C ceases when the coupling has been tightened a suitable or selected amount. The tongs T arethen disconnected from v,the string S and the string is lowered preparatory to connecting another stand of the pipe with the upper end of the string. The

switch 82 and the brake pedal |03 may be manipulated to bring the tong supporting unit on the table part I 3 to the correct position where its tong T may engage the upper section of the .coupling C to be made up. The above operations may be repeated in making up the entire string S.

The screw |32 may be adjusted so that the torque controlled drive means It assures the making up of the several connections C under a given rotational force. Accordingly, the string S maybe made up in such a manner that its This energizes the motor 56 to turn the outer table part I3 inl a counter-clockwise direction. The tongs 'I' carried by the base I0 holds the lower part of the string S against rotation while the tongs T carried by the rotating table part I3 cause the upper stand or section of the string to rotate so that the threads of thel coupling C are unthreaded. When the coupling C has been broken or unthreaded the tongs T are disengaged from the string S and the upper detached section or stand of pipe is removed and laid down or stacked in the derrick; The string, S is raised to bring the next tool joint or coupling C above the rotary table and the above operations are repeated until the entire string is broken down.

In both making up and breaking down the joints of a well string, the stem |08 carried by the post |06 may be left free to shift vertically so that the tongs T engaging the upper stand or section of pipe may shift vertically while the threads are made up or unthreaded. In carrying out the above described operations a single operator observes the gauge 'I0 and may control the switch 02 and the brake |03 and two operators may manipulate the tongs T. The operations may be carried out rapidly With practically no danger to the workmen or equipment.

In the event that the main drive I2 for the inner table part II fails or is out of commission the inner and outer table parts and I3 may be connected by means of the bars IIB so that the drive I4 may be utilized to operate the drilling tools. In this case the post |04 is detached from the base |,0 and removed before the drive I4 is put into operation. In some cases it may be desired to employ the drive I4 to rotate the well string for special operations where a torque controlled drive is desired. The screw |32 may be adjusted so that the switch 87 0perates to de-energize the motor 56 when any ported on the base, an outer part around the inner part rotatably supported on the base independently' of the inner part, means on the base and outer part to support tongs for engaging a well string, power means for rotating the outer part relative to the inner part, and a control for de-energizing the power means responsive to the resistance to rotation of the outer part.

5. Apparatus for use with a rotary table having a drive comprising' a rotatable part surrounding the table, an electric motor, a drive between the motor and the said part, a cradle supporting the motor to swing in response to resistance to rotation of said part, and a control responsive to swinging of the motor for de-energizing the motor when said resistance reaches a given value.

6. A rotary table of. the character described comprising an inner part, a rotatable outer part around the inner part, means on the outer part to support tongs for engaging a well string, a

influencing said circuit to de-energize the motor when the motor moves a given distance.

'7. A rotary table of the character described comprising an inner part, a rotatable outer part given or selected torque has lbuilt up in the drilling string.

Having described only a typical preferred form and application oi my invention, I do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to myself any variations or modifications that may appear to those skilled in the art or fall within the scope oi the following claims.

Having described my invention, I claim:

l. A rotary table for well drilling comprising a rotatable inner table part, power means for rotating said inner part, a rotatable outer table part around said inner part, and a separate power means for rotating said outer table part.

2. A rotary table for well drilling comprising a base, an inner table part supported on the base for rotation, drive means for rotating the inner table part, an outer table part around the inner table part rotatably supported on the base independently of the inner table part, a separate drive for rotating said outer table part, and tong supporting means on the base and the outer table part.

3. A rotary table for well drilling comprising separately mounted rotatable inner and outer parts, drive means for rotating said inner part, separate drive means for rotating the outer part independently of the inner part, and a control for the last named drive means responsive to the resistance to rotation of the outer part.

4. A rotary table of the character described comprising a base, an inner part rotatably suparound the inner part, means on the outer part to supportv tongs for engaging a well string, a motor, a drive between the motor and said outer part, means supporting the motor to move in response to resistance to rotation of the outer part, a control circuit governing the motor, manual switch means for said circuit operable to initiate and stop operation of the motor, and means iniluencing said circuit to de-energize the motor when the motor moves a given distance.

8. A rotary table of the character described comprising an inner part, a rotatable outer part around the inner part, means on the outer part to support tongs for engaging a well string, a reversible motor, a drive between the motor and said outer part whereby the motor rotates said outer part, means supporting the motor to move in response to resistance to rotation of the outer part in at least one direction, manual control means for initiating operation of the motor. and control means for stopping the motor in response to a given movement of the motor.

9. A rotary table of the character described comprising an inner part, a rotatable outer part around the inner part, means on the outer part to support tongs for engaging a well string, a reversible motor, a drive between the motor and said outer part whereby the motor rotates said outer part, means supporting the motor to move in response to resistance to rotation of the outer part in at least one direction, manual control means for initiating operation of the motor, control means for stopping the motor in response to a given movement of the motor, and means for adjusting the last named means to operate at a selected movement of the motor.

10. A rotary table o1' the character described comprising a base, an inner part rotatable on the base, an outer part around the inner part rotatably supported on the base independently of the inner part, means on the base and outer part to support tongs for engaging a well string, power means for rotating the outer part independently of the inner part, manual control means for starting and stopping the power means. and brake tatably supported on means for stopping -the said outer part in'any selected position. Y

11. A rotary table of the character described comprising an inner part, a rotatable outer part around the inner part, power means for driving the inner part, power means for rotating the outer part independently of the inner part, a torque control for de-energizing the last named power means when there is a given resistance to rotation of the said outer necting the said inner part with said outer part part, and means for con-- to be driven by the said last named power means.

12. A rotary table of the character described comprising a base, a rotatable inner part on the base, an outer part'around the inner part rotatably supported on the base independently of the inner part, releasable means for connecting the A table part supported on the base for rotation,

drive means for rotating the inner table part, an outer table part around `the inner table part rothe base independently of the 'inner table part, and a separate drive for rotating said outer table part.`

14. In a rotary table, the combination of a base, an inner table part rotatably supported cn the base, an outer table part around the inner table part rotatably supported on the base independently of the inner part, and' anti-friction hold-down' means on the base holding the' outer part against upward displacement. v `15. In a rotary table, the combination of a base,

A table part, a second string-engaging tongs, and means extending an inner table part rotatably supported 'on the base, an outer table part around the inner table part, a trough flange on the base, and anti-friction bearing means in the ange supporting the outer part on the base for independent rotation, the iiangebeing adapted to contain lubricant.

16. In a powerdriven rotary table, the combination of a base, an inner table part supported on the base for rotation, and an outer table part around the inner table part rotatably supported on the base independently of the inner table part. 17-. In a rotary table for handling a well string .having threaded couplings, a stationary base,

inner and outer table partsv separately mounted on the base for independent rotatio a tong supporting unit on the outer part rotatable therewith to support tongs where they may gripY the upper part of a well string coupling above said table parts, and a tong supporting unit fixed to the stationarybase 'inside of the .outer part andv ylin'ojecting upwardly therefrom to support tongs whereV they may grip the lower part of the well string coupling above said table parts.

18. In a rotary table, a'stationary base, inner and outer table parts separately mounted on the base for independent rotation, means on the inner part -for supporting a well string, a unit on vthe outer table part for supporting upper stringengaging tongs, there being a space between the .y

periphery of the inner table part and the outer unit for supporting lower through said space for securing said'second unit to the stationary base. v

. GUY K. CLAIRE.

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