US2595902A - Spinner elevator for pipe - Google Patents

Description

y 6, 1952 A. L. STONE 2,595,902

SPINNER ELEVATOR FOR PIPE Filed Dec. 25, 1948 3 Sheets-Sheet 1 W H II.

DERRICK |09'-- LEG SPINNER ELEVATOR ASSEMBLY mven'rom. F n coupmzsso n Li; TM

ATTORNEY.

y 6, 1952 A. STONE SPINNER ELEVATOR FOR PIPE 3 Sheets-Sheet 2 Filed Dec. 25, 1948 m M m u m M a I 8 9 6 MR 9 x a m m L m BMW \F \l '1 a u C 6, 4/ 7 A H\ m s H I G a wE m um v 4 W F. G n M F m n WY M J! B m o m fl i m a w W 3 a G F n m 4 2 m B, M

May 6, 1952 STONE 2,595,902

SPINNER ELEVATOR FOR .PIPE

Filed Dec. 23, 1948 3 Sheets-Sheet 3 87 FIG l2 1 I4 I02 I Q v I FIG. 8 2| FIG, l e (Siam/,mvnwon.

Patented May 6, 1952 Albert L. StonaBdondo Beach, Calif., assignor; hy'mesne assignments, to Standard Oil Devel;-

opment Company, Elizabeth, N.

tion-cf- Delaware J1, a corpora Application December 23, 1948, Serial N0. 66,966 s'claims. (01. 255-45 This application is a continuationimpart of SerialNo". '790,1-24, filed Decemb'er G; 1947; entitled S'pinn'er: Elevator for- Pipe," now abandoned.

This' application is also related to my applicae tion"Serial No. 56,402;Jflled-'October'25; 1948, entitled' Pipe"Elevator which claims the pipe elevator and. indexing means forming a portion of the" combined spinner and elevator of this application.

The present invention is directed to. an assembly. serving a as an. elevator and spinner. adapted for" suspen'din'gand: rotating vertical: sections of drill pipe. in? a: derrick.

When drilling boreholes using sections of pipe asthe drill stem, itiis necessary t'orotate sections of the pipe as'well as toxsuspend thetsectionsiof.

pipe in the derrick; Conventional :operations require an elevator." suspended from the traveling blocks: for suspending the drill pipe, tongs for breaking or: makingxupl-the joints of; pipe: and a spinning means, which may bearr'ope or: chain activated. bya' cathead, forcspinning the-pipe.

Conventional. elevators arranged to engage I with the shoulder defined by. the tool joint of drilllpi'peoran elevator plug screwed. intopthe,

upper :enda of: the length: of:- pipe to. be handled suffer :from several disadvantages well known to;

the art. These elevators must be manually en.- gaged: with and. disengaged: from' the drill pipe beinghandled. In addition; the requirement, that an external shoulderlbe providediorengagement with the elevator. is disadvantageous; In the interest of 'economics'as well" as good structural design, it is not-desirable to provide tool joints with external shoulders. Elevator? plugs are unsatisfactory because of thetime element involved in screwingandunscrewing the plugs-in the joint of pipe being handled; and .in addition; the use of these" plugs introduces-Zen;- additional hazard in" the handling ofibtheadi'ih .pipe;:.in'asmuch as it is sometimes-desirable :tO' rotateerthepipe' WhiI'esuspended from thea'elevators and; thei'elevator plug may come loose duringifth'e."rotationaloperation.

The'conventionalmeans f or spinning: stands. of pipe suffer from: several: disadvantages: If a chainorirope activated by a cathead is: employed,

an appreciable interval? of. time is required" for wrapping... the chain or; ropev around the pipe preparatoryv to the spinningoperation; When spinning out the jointno appreciable time: is required for removing the chain or ropebecause the cathead may pull on the rope until it is entirely: unwrapped fromthe pipe'but when spinning up joints :ofv pipe antappreciabler interval of time'iis' also required :to. remove the" rope or "chain from the pipe. In addition, the use of a ropev orchain to. spin the pipe.-involvesja.hazard and ofttimes: causes injury 'to the workman.

Devices. have been constructed. which are adapted to be engaged with the pipe for spinning it but heretofore such devices. have been'relativelyclumsy and-heavy as well as expensive and have suffered from-the same disadvantage as:

spinning ropes and chainsin-that an appreciable interval of time is required for-engaging'therdevice with the pipe preparatory to the spinning operation and disengaging it fromthepipet after the spinning operation has beencompleted.

It is an object of the-present invention-to provide atcombined elevatorand spinner forpipe;

Other objects and advantages of the present invention may beseen from the following description taken in conjunction with-thedrawing-in.

whicl'ia Fig. 1 is an -elevation showing an embodiment of the presentinvention as it appears suspended from the travelingb-lockand supporting a section of p .Fig. 2 is a view along lineI L-II of Fig. 1

Fig. 3- is a frag'inentaryview, partly in section,

of the device of: Fig. l witli the parts shown in:

the position they would normally occupy when the unloaded device is suspended; with the pipeengaging; parts in their retracted or disengaged position; 7 r

l 'igg l is afragmentaryview, partly in section,

of thedeviceoiliiglv with the parts-shown-in the position they'would occupy-afterrthe device. has been lowered to engage with-a-box endorv a, section of pipe sothat the pipe engaging-parts arein theiraexpanded or engaged-posltioma-nd the device rests on the engaged :pipe;

Fig. 5 is a fragmentary. view showing-details oi construction of parts which are -in-the same relativeposition as inFig. 3- whenthe'pipe engaging:

portion, isin its retracted. or its disengaged: positiomy Fig. 5a is; aviewrof a member of'theassembly.

Fig. 6 is a view showing details of construction of the same parts as shown in Fig. but with the parts in the same relative position as shown in Fig. 4 when the pipe engaging parts are in their engaged or expanded position;

Fig. 7 is an elevation, partly in section, of the pipe engaging portion or chuck of the embodiment of the foregoing figures;

Fig. 8 is a view taken along line VIII-VIII of Fig. 7;

Fig. 9 is a view taken along line IX-lX of Fig. 7;

Fig. 10 .is an elevation of a member of the assembly of Fig. 7;

Fig. 11 is an elevation, partly in section, of another member of the assembly of Fig. 7;

Fig. '12 is an elevation showing the details of construction of the signal bell of the embodiment of the foregoing figures;

Fig. 13 is a view illustrating the relationship between the indexing means of the device and the box of a tool joint with a portion of the tool joint cut away to show the upper end of its thread;

Fig. 14 is a view similar to Fig. 13 but with the indexing means and the tool joint thread in a different angular relationship;

Fig. 15 is a view looking upwardly in the indexing means shown in Figs. 13 and 14;

Fig. 16 is a view looking downwardly at the tool joint box of Figs. 13 and 14; and

Fig. 1'7 is a view taken along line XVII-XVII of Fig. 3.

For convenience, the device shown in the drawing has its principal parts or assemblies designated by letters and component parts of the assemblies or parts of the principal parts designated by numerals.

The principal parts or assemblies are chuck assembly A, mandrel B, piston assembly C, body D, power spring E, mandrel locking assembly F, housing G, compression spring H, bearing assembly I, releasing assembly K, signal assembly L and rotating unit M.

Of the parts enumerated'those from A through L-may be considered necessary for engaging with the threaded end of a pipe while unit M is the means for spinning or rotating the pipe.

In Fig. 1, housing G is suspended from traveling block I06 which in turn is suspended by drilling line ID! from derrick I 08. Guides I09 are mounted in derrick I98 with their upperand lower ends flared and the lower ends supplied with springs I99. The purpose of these guides is to provide counter torcue in addition to that supplied by the drilling line and weight of the traveling block to oppose the torque exerted through unit M on chuck assembly A.

'Chu'c't assembly A, as shown in Figs. 3, 4 and Figs. '7 through 1'1, consists of a compression ring I0, a plurality of jaws I I, sleeve I2, indexing ring I3 and guide cone I4. Sleeve I2 is slidably arranged in the lower portion of body D being nor mally supported from inwardly extending circumferential shoulder I5 of body D. Sleeve I2 defines a circular groove I! for receiving shoulders I8 of jaws II. The outer surface of sleeve I2 is provided with a longitudinally extending slot to receive key 8 for preventing rotation between body 'D and the sleeve. A radially extending screw 9 extends from the sleeve into a corresponding radial passage in a jaw II to prevent rotation between the jaws and the sleeve. This allows thg chuck assembly to move longitudinally but not'rotatably with respect to body D. I

Indexing ring I3 is split with the two halves secured together by cap screws I9 so that indexing ring I3 is in effect a member of constant diameter. Each jaw member I I defines a radially extending passage 29 and screws 2I mounted on indexing ring I3 extend slidably into each of said radial passages 20. Guide cone [4 defines radially extending slots 22. It is made up of two like parts held together by cap screw 23. The mode for securing the jaws to sleeve I2, indexing ring I3 and cone I4 allows the entire chuck assembly to move longitudinally with respect to body D and also allows jaw members II to move radially. The sleeve, indexing ring and guide cone are concentric and remain fixed in position with respect to each other at all times. Jaws II move radially but remain concentric with respect to the axis of chuck assembly A. Compression ring I0 biases the jaws radially inward so that normally they assume a contracted or disengaged position.

The outer surfaces of the jaw members II of chuck assembly A define a substantially complete screw thread 24 with the only incomplete portion of the thread being the space which separates the jaw sections. The inner surfaces of the jaw members define a passage 25 for receiving mandrel B. In the embodiment shown in the drawing, the lower portion of the mandrel is square in section and, accordingly, passage 25 is square in configuration. To prevent dirt and foreign particles from entering passage 25 the spaces between the sides of the adjacent jaw members I I are sealed by rubber packing members 26 and the space between guide cone I4 and jaw members II is packed ofi by packing ring 21.

The chuck assembly shown is adapted to engage with' the tapered thread such as may be employed for the tool joint of drill pipe. The lower surface of indexing ring I3 defines an indexing surface 28 which is in the shape of the lower surface of a thread extending through an arc of approximately 360. The indexing surface must extend through approximately this length of arc although satisfactory operation may be obtained if it is a few degrees less, say 355. If desired, the thread could extend through a greater length than 360 but the usable portion for indexing is limited to 360 and there is no advantage of extending it a greater distance. In order for this indexing means to operate properly the thread of the tool joint with which it is to engage should terminate as a true spiral. A tool joint thread of this character is shown in Figs. 13, 14, and 16.

Fig. 15 is a view of the indexing surface 28 looking upwardly. In this view line 29 represents the vertically extending shoulder with which spiral thread surface 28 terminates.

Fig. 13 is an elevation, partly in section, showing the index ring I3 immediately above tool joint 30. Tool joint 39 defines a thread 3| which terminates as a true spiral and ends in shoulder 32. This figure illustrates the relationship the indexing ring and the tool joint may assume when the elevator assembly is being lowered to engage the tool joint. In this figure shoulder 29' of the index ring overlaps by a few degrees shouljoint thread.

Fig. 14 is similar to Fig. 13 but shows index ring l3 rotated a few degrees (in the counterclockwise direction looking downwardly) with respect to shoulder 32 of the tool joint thread so that shoulder 29 will pass shoulder 32 upon lowering of the elevator assembly and indexing surface 28 will engage with thread 3| approximately one pitch below'the point they will engage in Fig. 13. When the indexing ring l3 does engage with thread 32 of the tool joint the thread 24 defined by jaws I will belined up properly with thread 3| of the tool joint so that the jaw members will properly expand into the tool joint thread. The Figs. 13 and 14 illustrate that the index 3 insures that the thread 24 of the chuck assembly will properly engage with thread 3| oi the tool joint at any relative angular position between the'indexing member I3 and the tool joint thread 3|.

Mandrel B, as shown in Figs. 5 and 6, consists of a lower tapered square section 40, an upper section of generally cylindrical shape 4|, an upper locking portion consisting of tapered surfaces 42 and 43, a lower locking portion consisting of tapered surfaces 44 and 45, packing rings 46 and an upper head 41.

Piston C is arranged to move mandrel B longitudinallybut is connected therewith so as to produce an initial jar for releasing the mandrel after the chuck A has been used for supporting a load. Piston C defines a cavity 48 for receiving head 41 of mandrel B. Cavity 48 is defined by cylindrical wall 49 and end wall 50. A circular inwardly extending ledge 5| encircles body 4| of the mandrel below head 41. Piston C defines an upwardly extending tube 52 which serves as a passage for compressed air. This passage discharges into radially extending passages 53 and thence into longitudinally extending passages 54 which discharge below piston C. The outer cylindrical surface of piston C is provided with packing ring 55.

Body D is of a somewhat irregular shape but is generally tubular having an upper wall portion 56 and having its upper end terminating in an outwardly extending shoulder 51 and defining an inwardly extending wall 58 which is pierced.

by a central passage 59. A tube 60 extends downwardly from wall 58. The outer surface of wall 56 defines key ways 56. Below wall 56 is an inwardly extending wall or shoulder 6| pierced by a central passage 62 and below wall 6| the body defines an inner cylindrical surface 63 having akey way 64 for. receiving key 8 and terminatingin lower shoulder IS. The lower' outer portion of body D defines ears 65 adapted for supporting the links of a conventional type elevator (not shown on the drawing), if desired.

Inwardly extending'wall or shoulder 6| defines or has attached, thereto a downwardly extending tube 66 which has an upper portion of its wall thicker than its lower portion to define shoulder '61 and is provided with longitudinally extending slots 68 in its thinner wall portion.

Piston C slides longitudinally within body D with packing ring 55 in contact with the inner Mandrel. B

Power spring'E is arranged within tube 60 with... itsupper endiin contact with. shoulder 51 and its lower end in contact with piston C sothat it exerts a downwardbias thereon. Outwardly-extending shoulder 51 serves as a support for compression spring I-I.

Mandrel looking assembly F is arranged for releasably locking mandrel B in either in up position or a down position. Whenmandrel B is locked in its up position; chuck assembly-A isring defines a central passage having a lower cylindrical portion15-and an upper tapered portion 16. Wedges-1| define locking surfaces 11 and 18' and an outer surface 19. Wedge members 1| are arrangedin longitudinally extending slots 68in tube 66 of body D and areencircled by locking ring 10 so that outer surfaces 19-are in contact with tapering surface 16 of thelock ing ring. Spring 12 biases locking ring'1i1 down-- wardly.

When mandrel B is in its up position, as shown in Figs. 3 and 5; it is locked against downward movement by contact of its tapered lockingsurface- 44 with looking surface 11 of wedges 11.- If mandrel B is raised to its up position by admitting compressed air into chamber 69, and if at this time locking ring 10 isfree to move under the influence of spring 12; spring 12 forces'the locking ring downwardly so that tapered surface 16 of the locking ring slides over surface 19 of the wedges forcing them inwardly until the locking surface 11 is in contact with the tapered locking surface 44 of the mandrel. mandrel in its up position against the bias exerted on the mandrel by power spring E through piston assembly C after the compressed air'is released from chamber 69.

The mandrel looking assembly F releases the mandrel from its up position when the locking ring 10 is moved upwardly with respect to body 10 comes in contact with the chuck assembly A. it is held against further movement while con-- tinued downward'movement of body D, wedges 1| and mandrel B allows the wedge members 1| to move radially outwardly as well as downwardly with body D thereby releasing mandrel- B so that power spring E can force it downwardly to its second position.

Mandrel locking assembly F. is able 'to lock mandrel B in its down position when body Dhas been lifted upwardly a sufrlcient distance to move. locking ring 15 out of contact with chuck assembly A. When this occurs spring 12 exerts its force against locking ring 10 in turn causing the tapered surface 15 of the locking ring to'force wedges 1| against the tapered locking surface 43 of mandrel B. This is illustrated in Figs. 4 and 6.

When the mandrel is locked in its up position, it is. locked against the bias exerted by-the power This locks the spring E, but when it is locked in its down position, it is looked against possible upward movement which might be produced by accidental release of compressed air into chamber 69 while the mandrel is supporting a load.

When mandrel locking assembly F has locked the mandrel in its down position, as shown in Figs. 4 and 6, it may be released by holding chuck A against downward movement and allowing the weight of body D to be exerted through tube 66 against the upper ends of wedge members II thereby forcing locking ring I to move upwardly with respect to wedge members 'II while the wedge members simultaneously move radially outwardly until they have moved a sufiicient distance to release mandrel B; after the weight of the body has been exerted on the upper ends of wedge members II, comprssed air may be admitted to chamber 69 to act against the lower surface of piston C thereby driving the piston upwardly, compressing power spring E and forcing the mandrel B to its up position.

Housing G is adapted to be supported from the traveling block and for this purpose is provided with a bail 80 at its upper end. The lower end of housing G defines a shoulder 0| arranged to support bearing assembly I. Bearing assembly I consists of lower race 82, upper race 83, and bearings 84. Supporting ring 85 rests on bearing assembly I and slidingly embraces wall portion 56 of body D. The outer periphery of ring 85 defines a ring gear 86 which cooperates with rotary unit M. The inner surface of ring 85is provided with longitudinally extending grooves for receiving keys 81 which fit slidingly in key ways 56 of body D.

Suspension spring H encircles wall portion 58 of body D with its lower end resting on supporting ring 85. When the elevator is supported from ball 80, the load is transmitted from chuck assembly A to body assembly D and from shoulder 51 of body D through spring H, ring 85 and bearing assembly I to shoulder 8I of housing G. Over-travel is provided so that housing G is free to slide downwardly in the event that the downward movement of body D is stopped when the device is being lowered. This provision of over-travel is particularly useful when engaging the device in that when the chuck assembly A engages with a stand of pipe the downward movement of the chuck as well as body D must be abruptly terminated but the housing G with the heavy traveling block may move downward the distance of the over-travel giving the driller an opportunity to stop the blocks and housing G after he has engaged the elevator with the load.

Compressed air for operating the assembly is obtained from a source of supply shown schematically as a vessel 90. The vessel is provided with a manifold 90 having an outlet 9I provided with valve 92 in turn connected through air hose 92 through fitting 93 to housing G. While tank 90 is shown in the drawing as a means for supplying compressed air, it will be understood that this is for illustrative purposes only and that conventional means such as an air compressor provided with a reservoir may be employed for this purpose.

Valve 92 is provided with an operating handle 94 shown in position a by solid lines and in position b by dashed lines. Valve 92 is provided with an exhaust vent 95. Fitting 93 in the top of housing G is connected to tube 96 which, for purposes of simplifying the drawing,

is shown as a portion of housing G. Tube 98 is concentric with tube 52 of piston assembly C and is provided at its lower end with packing 9'! which makes a fluid-tight seal with the outer surface of tube 52.

When the valve handle 94 is in position a, compressed air supply is in fluid communication with chamber 69 allowing air pressure to be exerted on the underside of piston assembly C. When the handle 94 of the valve is in position 1) it prevents flow of compressed air from air supply 90 and simultaneously exhausts chamber 69 to the atmosphere through exhaust vent 95.

The releasing assembly K is for the purpose of supplying compressed air pressure to chamber 69 for forcing piston C and mandrel B upwardly to allow chuck assembly to assume its retracted position. Assuming operating handle 94 is in its 12" position and the elevator load has been lowered to rest, the chuck assembly A may be released and mandrel B moved from its down to its up position by allowing the weight of body D to rest on wedges 'I I. which in turn forces locking ring I0 upwardly and allows the wedges to' move radially outward to release mandrel B. Thereupon the operator may move valve lever 94 from its b to its a position to apply air from air supply 90 to chamber 69. This air pressure causes piston assembly C to move upwardly until it strikes head 41 of mandrel B giving the mandrel a jar to loosen the squared portion 40 from jaws II and thereafter the continued application of air pressure against piston C forces it and mandrel B upwardly and against power spring E to its up position. Mandrel B is now in its up position and chuck A is retracted. The mandrel locking assembly F may then be allowed to lock the mandrel in its upper position by raising body D until locking ring T0 is moved upwardly out of contact with chuck assembly A and assumes the position shown in Figs. 3 and 5. The operator may then move valve handle 94 from a to b position thereby bleeding air from chamber 69 to the atmosphere and the mandrel B is locked in its up position by wedge member I I.

The valve lever 94 should remain in the b position all of the time the elevator is carrying its load. However, if the lever is accidentally moved to its a position while the chuck is carrying a load, mandrel B is locked against upward movement by the locking means previously described so that the accidental manipulation of valve lever 94 at this time will not cause the elevator to drop its load.

Guide funnel I05 is secured to the lower end of body D and aids in guiding the chuck assembly A into position for engaging with a section of pipe.

The signal assembly L may be any suitable signalling device arranged to give out a signal when the chuck A has assumed its expanded position. For purposes of illustration, an assembly is shown consisting of bell IOI, plunger I02 and striker arm I03. Plunger I02 is slidably arranged in a passage defined by shoulder 6| of body D with its lower end below the shoulder and its upper end above the shoulder. plunger I02 in its up position. When the device is being engaged with a section of pipe, after the piston C has been moved downwardly such a distance as to force mandrel B into chuck A to expand it for proper engagement with a tool joint, piston C strikes the upper end of plunger I02 and tomes It downwardly to rotate striker arm A spring I04 biases ,nel I 05 were not present it would be partially'con-' cealed by the box of the tool joint. However, if signal assembly L emits a signal the operator will know that the device has engaged properly with the threads of the jaws but if the signal assembly L fails to give out a signal the operator will know that the elevator has not engaged properly and that he must disengage the elevator from the load and make another attempt to stab.

Rotary unit M contains a reversible motor Iii) provided with a shaft I I I upon which is mounted pinion gear I I2. In the embodiment shown, motor I I is a compressed air motor and is connected to compressed air supply 90 through air hoses H3 and H4 and manifold 91). Hose H3 is controlled by valve I I5 and hose H4 is controlled by valve H6. With valve I I5 open and valve I I6 closed the motor rotates in one direction, while with valve IIG open and valve I I5 closed, it rotates in the opposite direction. It will be understood that if desired some other type of prime mover such as a hydraulic motor or electric motor may be employed instead of a compressed air motor for unit H0. Power is transmitted from pinion II 2 through gear 2' to teeth 86 of ring 85. Ring 85 is keyed to bodv D, in turn keyed to sleeve I2 which in turn is keyed to jaws II of the chuck assembly A. By en aging chuck assembly A with the section of drill pipe. a section of drill pipe may be spun in either direction as desired, by means of motor IIB.

From the foregoing description it will be seen that the combined spinner and elevator disclosed is adapted to be suspended from the traveling block and when lowered to stab a tool jo nt box the expanding chuck indexes automatically and engages automatically. When the chuck assembly A has engaged with a section of pipe, the pipe may be spun in either direction as desired. The elevator may be readily released from its load using compressed air to supply the power for this manipulative step.

When the device is used for spinning pipe, a torque is exerted by rotating unit M on chuck assembly A and this torque is opposed by a counter torque consisting of the weight of traveling blocks Hi6, the rigidity of the drilling line iii! and guides I09 carried by the derrick.

The device of the present invention will be seen to embody a substantial number of advantages. The provision of an apparatus capable of en aging with a section of pipe and of rotating the section of pipe when so engaged may substantially reduce the time and eifort required when drilling boreholes. At the same time, working conditions for the drilling crew are made less hazardous.

While I have disclosed a specific embodiment of the present invention, it will be evident to a workman skilled in the art that various changes in the size, shape and proportions of the parts of the members may be made without departing from the scope of the invention.

Having fully described and illustrated a preferred embodiment of the present invention, what 10 I desire to .claim as new and useful and to secure by .Letters Patent is:

1. A pipe elevator and spinner for suspending and spinninga section of pipe having its end terminating in a spiral screw thread comprising, in combination, a-housing adapted to be suspended from a traveling block, a pipe engagin assembly suspended therefrom for rotation with respect thereto and including a body, a chuck assembly carried by the lower end ofthe body including a plurality of jaw members mounted for radial movem nt outwardly from a'retracted position to an extended position, said jaw members defining least a inaior portion of a screw thread adapted to mate with the screw thread of said pipe when the jaw members are in their extended position, and means in contact with the jaw memb2rs for holding them in the retracted position, an indexing member carried by said jaw members for indexing the screw thread defined by said jaw members with the screw thread of said pipe, a slidable mandrel carried by the body in contact with each of said jaw members and adapted to assume an upper position with the jaw members in their retracted position and movable downwardly from its upper position to a lower position to move said jaw members radially outwardly to their extended position, means operatively connected with the mandrel for moving the mandrel from its upper position to its lower position and vice versa, a prime mover mounted on said housing and means inzluding said body interconnected between said prime mover and said chuck assembly for rotating the latter.

2. A device in accordance with claim 1 in which the indexing member is a ring of fixed diameter defining the surface of the end of a thread of fixed diameter corresponding to the end of the thread defined by said pipe.

3. A pipe elevator and spinner for suspending and rotating a section of pipe having its end terminating in a spiral screw thread comprising, in combination, a housing adapted to be suspended from a traveling block, a bearing assembly carried by thehousing, a body assembly arranged to be supported from said bearing assembly, a prime mover having a rotating shaft mounted on said housing, means for transmitting the rotative movement of the shaft of said prime mover to said body assembly, a chuck assembly normally carried by the lower end of the body in a lower position and mounted thereon for longitudinal movement upward with respect to said body to an upper position, the chuck assembly including a plurality of jaw members mounted for radial movement outwardly from a retracted position to an extended position, said jaw members defining at least a major portion of a spiral screw thread adapted to mate with the thread of said section of pipe when the jaw members are in their extended position, means in contact with the jaw members for holding them in the retracted position, an indexing member mounted on said jaw members and defining the surface of the end of a thread of xed diameter corresponding to the end of the thread of the section of pipe, a key and slot means securing the chuck assembly to the body to allow longitudinal movement while presenting angular movement, a slidable mandrel carried by the body in contact with each of said jaw members and adapted to assume an upper position to allow the jaw members of the chuck assembly to be moved radially inwardly to their retracted position and movable to a down position to force the jaw members radially outwardly to their ex- 1 1 tended position, means operatively connected with the mandrel and including a spring member arranged to bias the mandrel from its upper position to its lower position for moving the mandrel from its upper position to its lower position and vice versa, and a mandrel locking means carried by the body and releasably engageable with said mandrel when the mandrel is in its upper position and actuated by contact with the chuck assembly when the chuck assembly is moved from its lower position to its upper position for releasing the mandrel from it upper position to assume its lower position.

ALBERT L. STONE.

12 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,200,612 Helm Oct. 10, 1916 1,447,744 Wright Mar. 6, 1923 2,317,306 Smith Apr. 20, 1943 2,332,685 Auld et a1 Oct. 26, 1943

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