US2944793A - Drill pipe float valve apparatus - Google Patents

Description

July 12, 1960 M. a. CONRAD 2,944,793

Y Y DRILL PIPE FLOAT VALVE APPARATUS 'Filed Oct. 19,1955 2 Sheets-Sheet 1 I -'-Z- 60eo 6 l 45 INVENTOR. M9877 B. (Jo/W240 24 BY 6 7 m M M1 July/ 12, 1960 Q M. s. CONRAD I 2,944,793

DRILL PIPE FLOAT VALVE APPARATUS 2 Sheets-sheaf. 2

Ema.

Filed Oct. 19, 1956 .14 J5 INVENTOR.

I 1 3 BY 24 I m M M le-,7. 0.11. Fig,

Patented .luly 1a, rseo 2,944,793 DnILr. rrru FLoAr VALVE APPARATUS Martin B. Conrad, Downey, Calif., assignor to Baker-Oil Tools, Inc., Los Angeles, Calif., a corporation of Callfornia Filed Oct. 19,1956, Ser. No. 617,005 g I Claims. (Cl. 255-24) The present invention relates to subsurface well bore devices, and more particularly to drill pipe float valve apparatus for controlling the flow of fluid in a drill string from flowing through the drill pipe to the top of the hole. Y Itis also desirable to have the passage through the drill pipe-substantially unobstructed during the drilling operation to avoid restrictions tofthe flow. of the gaseous drill} ingfluid that is being forcedzd'own the drill p1pe, so thati it enits from the drill bit in sufficient quantity and velocity to carry the cuttings upwardly aroundthedrillpipe to the top of the hole.

, Ac cordingly,1t is an object of the present inventionto provide drill pipe-float apparatus capable of preventing upward flow of fluid in the drill pipe during longitudinal movement of the latter in the well bore, and which does not restrict flow offluid through the drill pipe during the drilling operation. Y Y Another object of the invention is to provide drill pipe float apparatus having a valve which istnormally closed during elevation or lowering of the drill pipe in the Well bore, the valve being fully opened upon the imposition of drilling weight on the drill bitsecured to thedrill pipe.

The imposition of drilling Weight on the bit eiiectsa shifting of the valve to a fully opened position complete through the drill pipe. a I. V p

n This invention possesses many other advantages, and has other objects which may bemade more clearly apparent from a consideration of a form in which it may be embodied. This form isshown in'the drawings accom- 1y out of .the path of flow of the drilling. fluid being forced 2 i I Fig. 8 is an enlarged fragmentary section taken along the line 88 on Fig. 6.

The drill pipe float valve apparatus A disclosed in the i drawings forms part of a string of drill pipe B, or other drill string, extending to the top of the hole C. It is secured in the drill pipestring in any. desirable location therewithin, usually adjacent a drill bit D with which the well bore is being produced. As disclosed, the apparatus A has its lower portion secured directly to the drill bit D, and its upper portion secured to an upper adjacent sec tion of drill pipeor a drill collar B. Y

The drill pipe float valve apparatus A includes an inner or upper tubular member or mandrel 10 having an upper threaded pin 11 for threaded reception within the adjacent lower box 12 of a section of drill pipe or a drill collar B forming part of the drill string extending to the top of the well bore C. The mandrel 10 is telescoped within a lower or outer tubular member or barrel 13 havinga lower threaded box 14 threadedly secured to the movement therebetween can occur. However, torque can betransmitted' fronrthe inneiirnember; 10 to theouter 1 member 13 by virtuelofa 'slidable spline connecti0ntheie5fl between; Thus, -the inner memberhas an intermediate'f portion 16' provided with longitudinally extending out- Y wardly directed splines 17 adaptedto. engage 'companion mwardlydirected, longitudinally extending splines18 on, the outer barrel or member 13. Actually, the inne'rJrnemberm is capable of occupying two main positions with respect to the outer member 13. One of these is an upper position, in which theupwardly directed shoulder poition,1 9 of the outwardlyextending splines 17 engage a two-piece thrust and retaining nut 20 threadedly secured to the 'upperfend portion of the barrel 13, and in which a valvedevice 21 within thebarrel is closed against'upwardj passage of fluid. Another position is a lowermost one, in which the valve, device 21 is held in a fully open condition, and wherein drilling weight can be transferred from the string of drill pipe B to the inner mandrel 10, and from the upper mandrel head 22 to the two-piece nut 20, the latter having its head portion 23 engaging the upper end of the barrel 13. This drilling weight is then transpanying and forming part of the present specification. it

will now be described in detail, for the purpose of illustrating the general principles of the invention; but itis to be understood that such detailed description is not to be taken in alimiting sense, since the scope of the invention Y Fig.3 isan enlarged cross-section taken along-theline 3. 3onFig.1;' V p Fig. 4' is an enlarged cross-section takenalong the line 4---4onFig.5; V Fig. 5, is a view corresponding'to Fig. 1 with the apparatusin another operating condition;

Fig. 6 is an enlarged fragmentary sectionof the float V valve portion of the apparatus disclosed in Fig, ,5;

Fig. 7 is an enlarged cross-section taken along the line ferred from the barrel 13 to the drill bit D therebelow, to

exert the proper penetrating force of the drill bit cutters 24 against thebottom 25 of the well bore being produced.

It is to be noted that the splined portion 16 of theinner member ill and thernandrel head 22 have substan tially greater external diameters, than the mandrel portion 26 therebetween, and that such mandrel portion preferably makes a sliding fit with the inner'wall 27 of. the

two-piece nut 20. The latter nut is made-in two pieces to' enable it to be placed laterally around the reduced diameter portion 26ofthe mandrel between the heads 22,

. 16 when the, mandred is in its-upper or extended position with respect to the barrel 13, the two'pieces then being shifted downwardly along the reduced diameter portion and'thread'ed into the companion upwardly threaded box 28 of the outer'barrel, until the lower shoulder 29 of the nut head is tightened against the upper end of the barrel.

rel 13; it serves to limit upward movement of the mandrel 10 with respect to the barrel 13, by virtue of engagement of the upper ends ,19 of the splines with the lower end of the nut; and it functions to transmit the drilling weight from the mandrel 10 to the barrel 1 3,be-

. ause of en ag m t f t e n hq sily i l the PPWE 3 end of the barrel 13 and the engagement of the upper mandrel head 22 with the upper end of the nut.

As stated above, the upward or extended position of the mandrel 1.0 within the barrel 13 permits a valve device 21 to close; whereas, a downward or lower location of the mandrel within the barrel effects an opening of the valve and a retention of such valve in its open .condition'. The valve deviceZl illustrated includes a valve body 39 mounted withinthe barrel 1% below its inwardly directed splines 113, the downward movement of the body being prevent d by engagement of its upper flange 31 with an upwardly facing shoulder 32 in the barrel. Its upward movement is prevented by a twopiece retaining ring 33 received within a companion internal groove 34 in .the barrel belowthe internal splines 18, this two-piece retalning ring 3 3*, well as the valve body 30, having a coaxial passage 35 therethrough through which a tubular valve head actuator and protector 36 can pass This latter member 36 constitutes the lower portion of the mandrel 10, depending from the splined portion 16 of the latter, and havingan external diameter substantially smaller than the internal diameter of the barrel 13, so as to provide an annular chamber 37 therewith below the valve body 30 This chamber terminates in an .inwardly directed shoulder 38 into which the lower end portion of the tubular actuator 36 is adapted to extendwhen the valve device 2d isin open condition.

A flapper valve head 39 is pivotally mounted on the valve body 30 at one side thereof. A fulcrum pin 40 is carried by a leg 41 depending from the valve body, flapper valve arms 42 being swingably mounted on the pin. The valve head 39-is adapted-to occupy a depending position, such as disclosed in Fig. 1, completely within the annular chambers-7 and is movable upwardly into engagement.

with 'a companion'valve seat 43, provided by the lower surface of the valve body, by spring devices 144 coiled around the fulcrum pin 40, each device having an arm 45 engaging the head 39 to urge it upwardly toward the valve seat, the other end of the spring device engaging the body 30 to prevent uncoiling of the spring.

When the mandrel 10 is in its lowermost position, such as disclosed in Fig. l, the peripheral portion of the tubular valve head actuator and protector 36 engages the valve head'39, to hold it to one side completely within the chamber 3-7. When the mandrel 1.0 is elevated within thebarrel 13 to the extent determined by engagement of its splined portion "16 with the thrust nut 20, the lower end 44 of the tubular protectoris disposed above the valve seat 43 and the springs 144 will shift the valve head into engagement with this seat, as disclosed in Figs. and 6. To insure against leakage between the head 39 and seat 43, the head may have a circular groove 145 therein receiving a suitable seal ring 46 adapted to engage the Valve seat. Leakage'is further prevented between the periphery of the tubular actuator portion 36 of the mandrel and the valve .bodyfil) by an internal seal 146, in the form of a rubber or rubber-like O'ring, disposed in ing of the valve head 39 and to minimize the shearing force applied to the fulcrum pin 40, the lower end 4411 of the mandrel is tapered from a central plane through its axis and parallel to the axis of the fulcrum pin, the direction of taper being in an upward and outward direction. With this arrangement, the portion of the lower end of the mandrel which engages the valve head 39 when in closed position will be disposed in such central plane, or much further removed from the fulcrum pin, thereby increasing the moment arm of the force opening the valve withrespect to the fulcrum pin '40, which facilitates opening of the valve and also reducing the shearing force imposed on the fulcrum pin. As a result, the hazard of bending, shearing, or otherwise deforming the fulcrum pin 4% is considerably reduced.

To maintain the proper orientation between the tapered surface 44a at the lower end of the mandrel and the valve head 39 and its fulcrum pin 40, the valve body 30, fulcrum pin and valve head 39 are rotationally fixed with respect to the mandrel 10 and the barrel 1%. To accompush this purpose, the two-piece retaining ring 33 is provided with an upwardly projecting orienting key 50 adapted to fit within an arcuate space 51 between ad'- jacent internal splines 18 (Fig. 7 particularly). The valve body 30 is prevented from turning with respect to the retaining ring 33 by an upwardly extending radial hey able splines 17, 18. Accordingly, the taper 44a on the lower end of the mandrel it; is held in a fixed angular an internal groove 47 in the body 30 and slidably and sealingly engaging the periphery of the tubular actuator. similarly, leakage around the exterior of the Valvebody 30 is pre'vented by a packing ring 48, such as a rubber or rubbenlike O ring, disposed in a peripheral groove 49 inthe body and engagingthe inner wall of the barrel 13.

'When the mandrel 10 is moved downwardly with respect to the barrel 13, its lower end 44 engages the valve head 39 and'swings it downwardly to a fully opened position. If the lower end of the tubular actuator portion 36 of the mandrel werestraight across and at right angles to" its axis, then the end portion of the tubular actuator closest to fulcrum 46 would engage the valve head and exert a substantial force to shift the valve head to an open position, depending, of course, upon the upward pressure on the-valve head 39 tending to keep it closed. The fereewould be at a maximum at this point, being exerted at a point closestto the fulcrum pin, thereby im-' posing a large shearing force thereon. To facilitate openposition with respect to the valve head 39 and its fulcrum pin 40. i

In assembling the apparatus A, the valve-body 30 is disposed within the outer barrel 13 with its flange 3 1 engaging'the barrel shoulder 32. Thereafter, the two pieces of the retaining ring 33 are inserted in the barrel, being shifted laterally away from each other into the internal groove 34, with the orienting key 56 disposed in an arcuate space 5-1 between adjacent internal splines 18 and the groove 53 receiving the radial key 52. When locatedin the groove 44, the retaining ring sections 33 are spaced apart (Fig. 7) However, their arcuate inner portions conform to the outside ,diameter of the tubular actuator member 36. The tubular mandrel 10 is then inserted through the upper end of the bagel, its splines 17 appropriately meshed with the internal splines 18 in the barrel, and with its tapered end 44d a propriately angularly' disposed respect tothe valve head The two-piece nut is then placed laterally around the reduced diameter portion 26 of the mandrel 10, whereupon he nut is shifted downwardly and is threaded into the upper end of the barrel to its fullest extent. The parts are thereby fully assembled, the mandrel ll being shjftable downwardly to its fullest extent so that the flapper valve head 39 is disposed completely within the annular chamber 37, or the mandrel can be shifted upwardly to its fullest extent within the barrel, with its lower end 44 disposed above the valve seat 4- 3, allowing the valve head to engage this seat, andthereby closing the apparatus againstupward passage of fluid therethrough. V

The apparatus A disclosed is secured at the appropriate location in the drill'string B, with a drill bit .D

connected therebelow, and is lowered in the we'll bore C. During such lowering movement, outer barrel .13 extends downwardly with respect to the mandrel It the thrust nut 20 engaging the upper splined shoulder 19 on the mandrel .(Fig. 5). With the parts in this position, the lower end 44 of the mandrel is disposedabove the valve seat 43 and the valve head 39 is shifted upwardly into engagement with its "valve seat.- Any gases, or other fluids, tending to new upwardly through the drill bit D and into the string of drill pipe B are prevented from gages the bottom 25 of the hole C being produced.

When this occurs, the drill string B is rotated, the rotary effort being transferred from the mandrel through the splined connection 17, 18 to the barrel 13, and from the latter to the drill bit D. The drill string B can now beshifted downwardly to impose drilling weight on the bit. Since the bit engages the bottom of the hole, the barrel 13 cannot move downwardly, permitting the mandrel It) to shift downwardly to the position shown in Fig. 1, wherein the lower end 44 of the mandrel has engaged the valve head 39 and pivoted it downwardly and outwardly to an open position, with'the face of the valve head engaged by the periphery of the tubular actuator 36 of the mandrel, which will hold the'latter com pletely to one side in the chamber 37. The mandrel shifts downwardly within the barrel to the extent determined by engagement of the upper mandrel head 22 with the thrust nut 29, at which time the lower end of the mandrel is disposed within the barrel flange 38 below the chamber 37, as shown in Fig. 1. Appropriate drilling Weight can now be imposed on the drill bit D through the mandrel head 22, thrust nut 20 and outer barrel 13, while the drilling fluid, which may be a gaseous medium,

and into the drill bit passage 60, discharging from the closed valve device 21. The

fapeafzsa ,rne'mbers' when said members'are ina relative contracted position; a valve device in one of said members adapted to .close the passage through said members when said members are in. extended position with respect to one another and 'stillisplined to one another; and means on one of said members engaging said valve device to shift it to passage opening position upon movement of 'said- I members to a relative contracted position in which drilling Weight is to be transmitted between said members.

. other member to a lower adjacent drill string portion;

latter to carry the cuttings upwardly around thejbit; .l

around the telescopic float valveappa'ratus, and back up to the top of the hole. The passage 61 through the float apparatus is continuous and unobstructed," and may have at least the same diameter as the passage through the other sections of drill pipe and drill collars Tin the drill string. Accordingly, a full flow ofc'ompressedygas' or compressed air" can pass down through the drill pipe string B to insure the removal of the cuttings from the bottom of the hole C and their conveyance to thetop of the latter. Y

When the drill bit D is to be" removed from the well bore, or when it is elevated from the bottom 25, the raising of the string of drill pipe shifts the mandrel '10 upwardly within the barrel 13 to the position disclosed in Fig. 5, with the lower end 44 of the mandrel disposed above the valve seat 43, allowing the springs 144 to shift the valve head 39 back into engagement with the valve seat 43. Accordingly, during elevatingmovernent of the drill string in the well bore, any fluid, such as gases and the like, in the well bore are prevented from flowing upwardly through the drill pipe B to the topfl-of the hole.

While the invention has beendescribedwithparticular reference to the drilling of a well with a gaseous medium; the apparatus is also usable in'the drilling of well'bores with drilling mud or other drilling fluid. The .drill pipe can be floated in the hole by virtue of the one-way valve action of the upward engagement of the valve head 39,

Whenever. the drilling operation is to commence, the act of imposing drilling weight on the bit D automatically shifts the valve 21 ,to

its fully open position, permitting'free and unimpeded pumping or forcing of-the drilling mud or -other.-fluid v down through the string of drill pipeto discharge from against its companion'seat 43;

thedrill bit. During this action, the valve head 3 9,as

Well as the valve seat 43, are protected from the action:

.of the drilling fluid, insuring it 1m and efiecme H The inventor claims: I

' Y 1. In apparatus, of the character described i outer tubular members telescopically splined toone another throughout the'full range oftheir telescopic movement';, r nea ns 'on one of said members for securingsaid one member toanupper adjacent drill string portion;

r'neans onthe otheriof said members for securing said.

other member toa lower adjacent drill string portion;

,means for transmitting drilling 'weight between, said between said members.

members when said members are in extended position with respect to one another and still splined to one an- .other; and means on the other of said members engaging said valve head to shift it from said seat upon move- I ment of said members to a relative contracted positionin which drilling weight is to be transmitted between said members. -1. 3. In: apparatus "of the characterdescribed:inner and outer tubular.memberstelescopicallysplined to one another th'roughoutthe full range-of their telescopic' movemerit;- nieansvon said inner member for securing said inner member to an upper adjacent drillstring section;

means 'on said outer memberffor, securing-said outer member to a lower adjacent drill stringportion; means for transmitting drilling weight between said members when said members are in arelative contracted position; a valve device in said outer member adapted to close.

the passage through said members when said innermem-v ber'is elevated relative 'to said'out'er member and still splinedto said outer member; and means on said inner memberi'engageable with saidvalve device to shift it to passage opening position upon lowering movement of. 7 said inner member with respect to said outer member toward a positionin which drilling weight is to be transmitted between said members.

4. In apparatus of the character described: inner and outer tubular members telescopically splined to one another throughout the full range of their telescopicmovement; means on said inner member for securing said inner member-to an upper adjacent drill'string section;

means onsaid outer member for securing said outer member to a lower adjacent drill string portion; means for transmitting drilling weight betweensaid members when said members :are in a relative contracted position;

a valve'iseat on said outer member; a valveheadin said outer member movable upwardly into engagement with said-seat to close the passage through said members wherisaid inner member is elevated relative to said. outer member and still splined to said outer member; and

7 means on said inner member engageable with said; head to shift it fromsaidseat-upon lowering movement-of said inner member relative to said outer member toward a position in which drilling weight'is to be transmitted 5 .:In apparatusxof the character. :describediinnerand. outer tubular. members telescopically splined to one an: other throughout the full-range of their telescopic mov'e-.

ment; means on said. inner member for securing: said inner member to an upper adjacent string section; v

means on saidlouter member .forsecuring said outermember to alower adjacent drill string portion; coen:

gageable means on said membersiforttransmitting drillirig weight therebetweenl when said members. are in .a

relative contracted position; a valve seat on said outer member; a valve head in said outer member movable upwardly into engagement with said seat to close the passage through said members when said inner member is elevated relative to said outer member and still splined to said outer member; and tubular means on said inner member engageable with said head to shift it from said seat upon lowering movement of said inner member relative to said outer member toward a position in which said coengageable means is engaged, said tubular means being disposed substantially completely across said head when said coengageable means is engaged to prevent said head from having substantial contact with drilling fluid forced through said tubular means.

6. In apparatus of the character described: inner and outer tubular members telescopically splined to one another throughout the full range of their telescopic movement; means on said inner member for securing said inner member to an upper adjacent drill string section; means on said outer member for securing said outer member to alower adjacent drill string portion; coengageable means on said members for transmitting drilling weight therebet'ween when said members are in a relative contracted position; .a valve seat on said outer member; a valve head pivotally carried by said outer member and movable upwardly into engagement with said seat to. close thepassage through said members when said inner member is elevated relative. to said outer member and still splined to said outer member; and a tubular actuator secured to said inner member and adapted to extend through said seat to engage said head and swing it downwardly away from said seat upon lowering movement of said inner member relative to said outer member toward a position in which said coengageable means is engaged, said tubular actuator being disposed substantially completely across said head when said coengageable means is engaged.

7. In. apparatus of the character described: inner and outer tubular members telescopically splined to one another; means on said inner member for securing said inner member to an upper adjacent drill string section; means on said outer member for securing said outer member to a lower adjacent drill string portion; coengageable means on said members for transmitting drilling weight therebetween when said members are in a relative contracted position; a valve seat on said outer member having an opening surrounded by a planar seating surface; a valve head pivotally carried by said outer member and having a planar surface engageable with said planar seating surface, said head being movable upwardly to engage its planar surface with said seating surface to close the passagethroug'h said members when said. inner member is elevated relative to said outer member; and a tubular actuator secured to said inner member and adapted to' extend through said seat opening to engage said head and swing it downwardly away from said seating. surface upon lowering movement of said inner member relative to said outer member toward a position in which said coengageable means is engaged, said tubular actuatorbeing disposed substantially completely across said head when said coengageable means isengaged; the lower end of said tubular actuator being tapered in an upward direction laterally toward the pivot axisof said valve head. 7 a i 8. In apparatus of the character described: inner and 8 with an opening surrounded by a planar seating surface; a valve head pivotally mounted on said body and having a. planar surface engageable with said planar seating surface, said head being movable upwardly to engage its planar surface with said seating surface to close the passage through said members when said inner member is elevated relative to said outermember; a tubular actuator secured to said inner member and adapted to extend through said valve body and opening to engage said head and swing it downwardly away from said seating surface upon lowering movement of said inner member relative to said outer member toward a position in which said coengageable means is engaged; the lower end of said tubular actuator being tapered in an upward direction laterally toward the pivot axis of said head; and means preventing arcuate movement of said' valve body relative to said outer member.

9. In apparatus of the character described: inner and outer tubular members telescopically splined to one another; means on said inner member for securing said inner member to an upper adjacent drill string section; means on said outer member for securing said outer member to a lower adjacent drill string portion; said inner member having a guide portion above its splined area of lesser diameter than the diameter across said splined area; a sectional nut threadedly secured to the upper portion of said outer member above the splined areasof said membersand slidably receiving said inner member; means onsaid innermember engageable with said nut to transmit drilling weight between said mern" bers when said members are in a relative contracted position; a valve device in said outer member adapted to close the passage through said members when said guide portion of said inner member is elevated-relative to said outer member; and means on said inner member engageable with said valve device to shift it to passage opening position upon lowering movement of said inner member with respect to said outer member toward a position in which said means on said inner member is engageable with said nut.- i

10. In apparatus of the character described: inner and outer tubular members telescopically splined to one another; means on said inner member for securing said inner member to an adjacent drill string portion; means on said outer member for securing said outer member to another adjacent drill string portion; said inner member having a guide portion to one side of its splined area of lesser diameter than the diameter of said splined area; a sectional nut threadedly secured to an end. portion of said outer member to one side of the splined areas of said members and slidably receiving said guide portion of said innermelmber; and means on said innermember engageable with said nut to transmit drilling weight between said members when said members are in a relative contracted position.

11. In apparatus ofthe character described: an outer tubular member; an inner tubular member telescopically disposed within said outer member; said outer member having internalsplines; said inner member having external splines engaging said internal splines throughout the full range of telescopic movement between said outer tubular members telescopically splined to one an- V said outer member and having a valve, seat provided members; means on one of said members for securing said one, member to an upper adjacent drill stri'n'g portion; means on the other of said members for securing said other member to a lower adjacent drill string portion; means for transmitting drilling weight betweensaid memberswhen said members are in a relative contracted position; a'valve device in one of said members adapted to close the passage through said members when said members are in extended position withrespect tonne another and still splined to one another; and meanson one ofisaid members engaging said valve device to shift it to passage opening position upon movement of said members to a relative contracted position in which drilling weight is to be transmitted between said members.

12. In apparatus of the character described: an outer tubular member; an inner tubular member telescopically disposed within said outer member; said outer member having internal splines; said inner member having external splines engaging said internal splines throughout the full range of telescopic movement between said members; means on one of said members for securing said one member to an upper adjacent drill string portion; means on the other of said members for securing said other member to a lower adjacent drill string portion; coengageable means on said members above said external and internal splines for transmitting drilling weight between said members when said members are in a relative contracted position; a valve device in one of said members adapted to close the passage-through'said members when said members are in extended position with respect to one another and still splined to one another; and means on one of said members engaging said valve device to shift it to passageopening position upon movement of said members to a relative contracted position in which drilling weight is to be transmitted between said members.

13. In apparatus of the character described: an outer tubular member; an inner tubular member telescopically disposed within said outer member; said outer member having internal splines; said inner member having external splines engaging said internal splines throughout the full range of telescopic movement between said mem- 10 ternal splines engaging said internal splines through the full range of telescopic movement between said members; means on said inner member for securing said inner member to an upper adjacent drill string section; means on said outer member for securing said outer'member to a lower adjacent drill string portion; said inner member having a guide portion above its splined area of lesser diameter than the diameter across said splined area; a sectional nut threadedly secured to the upper portion of said outer member above said internal splines and slidably receiving said guide portion of said inner member above said external splines; means on said inner member engageable with said nut to transmit drilling 7 members when saidinner member is elevated relative to said outer member and still splined to said outer member;

a lowering movement of said inner member with respect to bers; means on said inner member for securing said inner member to an upper adjacent drill string section; means on said outer member for securing said outermember to a lower adjacent drill string portion; means for trans mitting drilling Weight between said members when said members are in a relative contracted position; a valve seat on said outer member; a valve head in said outer member movable upwardly into engagement with said seat to close the passage through said memberswhen said inner member is elevated relative to said outer member and still splined to said outer member; and means on said inner member engageable with said head to shift it from said seat upon lowering movement of said inner member relative to said outer member toward a position in which drilling weight is to be transmitted between said members.

14. In apparatus of the character described: an outer tubular member; an inner tubular member telescopically disposed within said outer member; said outer member having internal splines; said inner member having exsaid outer member toward a position in which said means on said inner member is engageable with said nut.

15. In apparatus of the character described: an outer tubular member; an inner tubular member telescopically disposed within said outer member; said outer member having'internal splines; said inner member having ex- 1 ternal splines engaging said internal splines throughout the full range of telescopic movement between said members; means on said inner member for securing said inner member to an adjacent drill string portion; means on said outer member for securing said outer member to another adjacent drill string portion; said inner member having a guide portion to one side. of :its splined area of lesser diameter than the diameter of said splined area; a sectional nut threadedly secured to an end portion of said outer member to said one side of said internal splines and slidably receiving the portion of said inner member to one side of said external splines; and means on said inner member engageable with said nut to transmit drilling weight between said members when said members are in a relative contracted position.

References Cited in the file of this patent UNITED STATES PATENTS 857,862 Best June 25, 1907 2,354,310 Goodwin July 25, 1944 2,620,165 Crickmer Dec. 2, 1952 2,624,549 Wallace Jan. 6, 1953 2,768,695 Althouse et a1. Oct. 1-0, 1956

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