GB2141509A - Coupling for tubular members - Google Patents

Abstract

Internally-grooved tubular members (10, 12), for example sections of a tubular casing for disposition in the earth to receive and guide geophysical instruments, are coupled together end-to-end by snap-action couplings. An open-ended coupling sleeve (14) has a central internal shouldered circumferential recess (36) which interlocks with a shouldered external segmental collar (26) on the end of a nipple (16) of reduced diameter constituting an end portion of each tubular (10, 12). Each nipple (16) is divided by axial slits (22) into three inwardly-deflectable springy segments (24). When the nipple is inserted into one end of the sleeve, segments (24) are deflected inwardly until the collar segments (26) snap into and interlock with the recess (36). A double-ended boss (38) cooperates with notches (30) in the ends of the nipples (16) to provide angular location and relative orientation of the tubular members (10, 12) with their longitudinal grooves (18) in alignment to form continuous internal guideways. <IMAGE>

Description

SPECIFICATION Coupling arrangements for tubular members This invention relates to coupling arrangements for tubular members and fittings and to their use.

The invention is primarily although not exclusively concerned with a tubular conduit coupling system for tubular members which is particularly useful in the assembly of an elongated tubular casing disposed in the earth for the reception and guidance of geophysical instruments used in making subsurface readings such as readings of inclination due to earth movement, pore water presence or pressures and the like. Of course, other fields of use will occur to those who commonly assemble tubular systems, including those systems which do not utilize the fluid seal means and other specialized features commonly associated with the geological and geophysical reading and sampling field.

Tubular casings assembled from tubular sections are commonly inserted into the earth in well holes or drill holes and various instruments are caused to move therein to produce geophysical readings. Typical instruments for detecting or determining movement in geological formations are called inclinometers. Fluid organs pressure measuring devices are commonly called piezometers. Usually such inclinometer and piezometer instruments take the form of a torpedolike body that is moved through the tubular casing. In the case of inclinometers the instruments have rollers or wheels usually in opposed pairs or pairs of pairs, typically disposed at 90 degrees to each other. The tubular casings for inclinometer or slope detecting instruments usually have longitudinal grooves to receive, orient and guide the torpedo by the rollers or wheels.

For convenience of manufacture and to facilitate transport of unassembled tubular casing sections their length is commonly limited to about 3 metres (ten feet). In assembling enough sections to produce a casing of extended length it will be seen that there will be required a plurality of couplings between the end-to-end disposed casing sections. For this purpose there is required a male/female coupling system which can be configured to maintain the orientation of the longitudinal grooves while facilitating field assembly by means of simple sliding fit and snaplock and without the need for adhesives.

Illustrative of prior art known to us is the U.S. Patent No. 4,258,788 issued 3/31/81 to F.D.Patten wherein is shown a coupling in the form of a sleeve to receive the end of a tubular casing section. The parts are secured together against longitudinal displacement by a flexible shear fastener strand being inserted into a matching and cooperable annular receiver passage which is part in the sleeve and part in the casing section. Fluid-tight O-ring seal means are also used between the sleeve interior and the casing section exterior.A principal object of the present invention is to provide an improved interlock system for rapidly and securely assembling casing sections to coupling members, which avoids and eliminates the necessity to use flexible shear fasteners and which operates by simple relative endwise or lengthwise sliding movement between the coupling member and the tubular casing.

Other tube-to-sleeve fastener systems employing matched grooves and flexible shear fastener strands may be seen in the U.S.Patent 3,934,615 issued to Lukonisky and Gamble on January 27, 1976. Also see the Medney U.S.Patent 3,606,402 issued September 1971 in which flexible shear fasteners are disclosed as used in coupled tubular assembles.

In the case of interiorly grooved casing sections it is required that the grooves throughout the assembly be like-oriented and continuous. In the mentioned prior art this was accomplished by providing an internal shouldered reduced bore within a coupling sleeve against which the ends of opposite casing sections abutted. Such reduced bore portion has an outwardly directed integrally formed tongue and the end of the casing section was notched to engage said tongue to ensure correct orientation and non-rotation. Also, the casing section end abutted the shoulder of reduced bore. it has been another object of the present invention to eliminate the reduced bore within the coupling sleeve and to enable direct end-to-end abutment of opposed casing section ends to be employed so that any internal grooved tracks are practically continuous.A further object has been to facilitate the use of an improved arrangement for angularly locating the casing sections in their correct relative orientations for this purpose.

According to the present invention, there is provided for use in a tubular conduit system a coupling arrangement between a tubular member and a female member, for example a coupling sleeve or an end cap, which arrangement comprises: an unthreaded nipple portion at one end of the tubular member, the nipple portion being formed with inwardly deflectable springy segments having external shouldered lugs, and the female member having a socket to receive said nipple portion and adapted to receive said lugs and to deflect said segments inwardly when the nipple portion is introduced into the socket, there being a shouldered recess in the internal circumferential surface of the socket to receive and interlock with the shouldered lugs so as to secure the coupling when the nipple portion is inserted into the socket.

Conveniently the shouldered lugs in the inwardly deflectable segments may together consti tute a segmented shouldered external collar extending at least partially around the nipple portion. This collar may have a part-cylindrical exterior and may extend circumferentially around the end of the nipple portion, the socket including a cylindrical shouldered recess to receive and interlock with the segmental shouldered collar.

In a preferred form of the invention, the female member may be a tubular sleeve having communicating sockets respectively opening through its opposite ends, to receive respectively the nipple portions of two of the said tubular members disposed end-to-end in axial alignment.

Where the two end-to-end disposed tubulars of such an arrangement have like internal longitudinal grooves, there may be alignment means positioned within the socket of the sleeve to cooperate with formations on adjacent ends of the tubular members so as to effect and maintain alignment of said internal longitudinal grooves when the coupling is secured. This alignment means may comprise a double-ended boss which is wall-mounted within the female member, the nipple portion of each tubular member having a notch to receive and engage one end of said boss.

One widely used method of endwise interlocking of tubulars is to provide a coupling sleeve having a bore of essentially the same diameter as the exterior of the tubular casing sections and having an interior keying mechanism to index the casing sections into interior groove alignment.

An adhesive is then used to glue the coupling sleeve and casing sections together in a permanent bond. The resulting assembly cannot be disassembled without damage to the ends of the casing sections. Although adhesive might possibly be used in the mounting of such an alignment boss in the sleeve at the time of its fabrication, the coupling arrangement of the present invention does not need adhesive for field assembly. Disassembly is accomplished by spiral cutting the female member, e.g. the coupling sleeve, from end to end, or other suitable cutting operation so that the member or coupling sleeve may be sprung to an enlarged diameter allowing the tubular casing section to be withdrawn without damage.

In view of the recited objects, and other objects which will become apparent from the following detailed disclosure, it will be seen that alternatively this invention may be regarded as embracing a coupling system for tubular members, preferably cylindrical tubular members, in whch there is an unthreaded nipple portion (referred to as a nipple in this specification) at the end of a tubular that is formed with several detent means which may be deflected inwardly by radially directed forces. For example, the detent means may form a segmental shouldered collar extending circumferentially about the end of the nipple portion to form exterior lugs provided with locking shoulders.Assembly is effected by inserting the nipple into a female member which may be in the form of a coupling sleeve which is internally sized to form a socket which will receive and yet deflect the springy nipple segments inwardly. Within the socket there is a recess and shoulder means to receive and automatically interlock with the segmented shouldered collar on the nipple to mechanically secure the coupling assembly upon full insertion of the nipple into the coupling.

For those applications where the tubulars and couplings are to be utilized as a casing for geological and geophysical readings and sampling, the coupling system can be configured with orientation means and/cr fluid seal means. The orientation means may be an orientation boss installed longitudinally in the interior cylindrical recessed area of the coupling which boss mates with an orientation notch formed in the end of one or more springy segments of the nipple of each of the joining tubulars. The orientation notch is.located at a precisely predetermined location with respect to interior grooves. The fluid seal means rnay be an O-ring placed in a.

shallow shouldered groove formed in the nipple or coupling at a location which clears the ends of the slots between the springy segments of the nipple and effects a seal between the outer surface of the nipple and the inner surface of the coupling.

The invention from another aspect comprises apparatus for use in sub-surface investigations in geological formation, in which apparatus a plurality of longitudinally aligned tubulars is assembled and is coupled together in end-to-end fashion by a coupling arrangement comprising: tubulars each having at each end thereof an unthreaded nipple portion of reduced diameter divided by longitudinal slots into a plurality of inwardly-deflectable springy segments; on each nipple portion a segmental shoulder formed of lugs extending circumferentially about the end of the nipple portion; a coupling sleeve having oppositely directed sockets to receive the nipple portions of a pair of tubulars disposed end-to-end; said sleeve having a cylindrical recess located in the mid-portion of its inner wall and including an double-ended orienting boss affixed in said recess; ; the nipple portions of said tubulars having notches to engage said double-ended boss and thereby to limit their inward incursion within said sleeve and to fixedly orient said tubulars; and circumferentially spaced longitudinal internal grooves in said tubulars all having like relationship to said notches for assembly in alignment to form continuous uninterrupted tracks for probes to move longitudinally within said apparatus.

The preferred embodiment of this invention and its accompanying drawings disclose tubulars and a coupling which incorporate a longitudinally-installed orientation boss and a fluid seal means. These may be deleted where the requirement for these means are absent without compromising the simplicity of the fabrication and ease of field assembly inherent in this novel tubular coupling system.

The invention can be carried into practice in various ways, but one specific embodiment thereof will now be described by way of example only and with reference to the accompanying drawings in which: Figure 1 is a longitudinal exploded view of a coupling sleeve and end-to-end disposed tubulars with portions broken away and shown in section for convenience of illustration; Figures 2, 3 and 4 are cross-sectional views taken in the respective planes 2-2, 3-3, and 4-4 of Fig. 1.

Figure 5 is a side view partially in section of an end cap attached to the end of a tubular; and Figure 6 is a longitudinal elevation view of an assembly of tubulars and a coupling sleeve with portions shown in cross-sections.

Referring to Fig. 1, end portions of end-to-end disposed tubulars 10 and 12 are shown relative to a coupling sleeve 14 with which they are to be assembled so as to produce continuity throughout the tubulars 10 and 12 and others likewise assembled, for example to form a tubular casing for underground instrumentation.

Tubulars 10 and 12 have nipples 16 at each end, and internal grooves 18 extending from end to end and spaced about the inner surface of the respective tubulars. Usually four equispaced grooves 18 are provided per tubular as best seen in Figs. 2 and 3. The nipples 16 are machined from and are of smaller diameter than the main bodies of the tubulars 10 and 12 and are separated from the main bodies of the tubular by annular shoulders 20. Each nipple 16 is divided by slots 22 into inwardly deflectable springy segments 24, usually three in number as is best shown in Fig. 2 and Fig. 3. The ends of said segments 24 have a segmented shouldered collar extending circumferentially about the end of nipple 16 to form external lugs 26 that outstand and provide shoulders 28.In the embodiment shown the lugs are formed by a decreased-diameter zone of the tubular 10 or 12 machined or otherwise formed between the shoulders 20 and 28 to a diameter smaller than the outer diameter of the tubulars. Each tubular end has an orientation notch 30. The nipples may each be equipped with a groove and 0being 48 positioned between the shoulder 20 and the inner ends of slots 22.

Referring again to Fig. 1, the coupling sleeve 14 has oppositely-open mouths 32 at its ends forming sockets into which the nipples 16 of tubulars are inserted for assembly of the coupling system. The internal diameter of each mouth 32 is sudstantially equal to the diameter of nipple 16 and somewhat less than the external diameter of the lugs 26 so that when the same are inserted into a mouth 32, the springy segments 24 are deflected inwardly as permitted by the slots 22. The edge of mouth 32 has an inwardly directed bevel to facilitate entry of the nipple 16 which correspondingly has a chamfer around its end for the same purpose.

Internally, coupling sleeve 14 has a cylindrical recess 36 which includes a double-ended orientating boss 38 mounted at a fixed location by means of pins 50 and/or adhesive in the middle lengthwise of the coupling 14. Boss 38, which has its interior surface flush with the inside diameter of the inserted nipple 16, is adapted to cooperate with the orientation notches 30 in each end of tubulars 10 and 12. As a nipple 16 is pressed into coupling 14 with its springy segments 24 deflecting inwardly, it eventually reaches the boss 38 and the recess 36.

When orientated so that one end of the boss 38 mates with orientation notch 30, the nipple 16 may be further inserted until its lugs 26 snap into recess 36 whereupon the inwardly-deflecting forces on segments 24 are relieved. Due to the inherent springy nature of the segments 24, the shoulders 28 engage the internal annular shoulder 39 at the edge of the recess 36. This provides an interlock that indexes (orientates) the tubulars and prevents withdrawal of the nipples 16 from within the coupling 14, until and unless the sleeve is expanded radially or the segments are again deflected inwardly permitting their withdrawal. As previously indicated, the sleeve may be spirally cut from end to end, or otherwise cut to enable it to be radially expanded for this purpose.

The cap or closed-end member 40 shown in Fig. 5 resembles a half-coupling with an end wall 42 positioned at one end of a recess 44 and forming the member into a cap. The cap mouth has an interior bevel. The nipple 16 and its lugs 26 engage in the recess 44 as described above to lock the end cap member to a tubular end. Such an end cap is usually applied to the entering end of a string of tubulars being assembled and inserted into the earth. Other fittings resembling well-known pipe or tube fittings such as tees, elbows, crosses and the like may be formed with a socket having the appropriate internal bevel, diameter and cylindrical recess to be used herein in conjunction with the appropriately configured tubulars to apply the snap-fit coupling system taught herein for other uses.

While the sizes of components, their relative proportions, and the materials employed in manufacture will be apparent, a current prototype embodying the invention has the following dimensions and properties: -external diameter of - ca 84.9 mm tubulars 10 and 12 (3 11/32 inches) -external diameter of lug 26 - 82.5 mm (3 1 /4 inches) -length of lug 26 12.7 mm (1/2 inch) -diameter of nipple 16 - ca 81.75 mm (3 7/32 inches) -length of nipple 16 - 61.9 mm (2 7/16 inches) -number of slots 22 - 3 -length of slots 22 61.9 mm (2 1/4 inches) -width of mouth of - 12.7 mm orientation notch 30 (1 /2 inch) -length of coupling 14 ~ 152.4 mm (6 inches) -external diameter coupling 14 - 88.9 mm (3 1/2 inches) -internal diameter coupling 14 - 81 mm (3 3/16 inches) -width of recess 36 - ca 25.4 mm (1 inch) -depth of recess 36 - 1.59 mm (1/16 inch) -width of orientation boss 38 - 12.7 mm (1/2 inch) -material - polyvinyl chloride or acrylonitrile-butadiene-styrene

Claims (12)

1. For use in a tubular conduit system, a coupling arrangement between a tubular member and a female member, comprising: an unthreaded nipple portion at one end of the tubular member, the nipple portion being formed with inwardly deflectable springy segments having external shouldered lugs, and the female member having a socket to receive said nipple portion and adapted to receive said lugs and to deflect said segments inwardly when the nipple portion is introduced into the socket, there being a shouldered recess in the internal circumferential surface of the socket to receive and interlock with the shouldered lugs so as to secure the coupling when the nipple portion is inserted into the socket.

2. The structure of Claim 1 in which the shouldered lugs on the inwardly deflectable segments together constitute a segmental shouldered external collar extending at least partially around the nipple portion.

3. The structure of Claim 2 in which the segmental shouldered collar extends circumferentially around the end of the nipple portion, and the socket includes a cylindrical shouldered recess to receive and interlock with the segmental shouldered collar.

4. The structure of any one of Claims 1 to 3 including a fluid seal means between the nipple portion and the socket.

5. The structure of any one of Claims 1 to 4, in which the nipple portion is divided by slots into at least three segments.

6. The structure of Claim 5 in which the nipple portion is divided into segments by narrow slots each extending from the end of the nipple portion and terminating at a location spacedapart from the inner extremity of the nipple portion.

7. The structure of any one of Claims 1 to 6, in which the socket of the female member has a fluid-tight bottom and the female member comprises an end cap.

8. The structure of any one of Claims 1 to 6, in which the female member is a tubular sleeve and has communicating sockets respectively opening through its opposite ends, to receive respectively the nipple portions of two of the said tubular members disposed end-to-end in axial alignment.

9. The structure of Claim 8 in which when the nipple portions of the said two tubulars are inserted into the respective sockets, their shouldered lugs are received in and interlock with one and the same shouldered recess in the sleeve and the ends of the two nipples are closely opposed to one another.

10. The structure of Claim 8 or Claim 9, wherein the said two end-to-end disposed tubular members have like internal longitudinal grooves, and which includes alignment means posi tioned within the socket of the sleeve to cooperate with formations on adjacent ends of the tubular members so as to effect and maintain alignment of said internal longitudinal grooves when the coupling is secured.

11. The structure of Claim 10 in which the said alignment means comprises a double-ended boss which is wall-mounted within the sleeve, and in which the nipple portion of each tubular member has a notch to receive and engage one end of said boss.

12. An assembly of aligned tubular conduit members, in which at least two adjacent tubular conduit members are connected together by a coupling as claimed in any one of Claims 1 to 11.

12. The structure of any one of Claims 8 to 11, including annular fluid seal means between each nipple portion and the socket with which it is associated.

13. The structure of any one of the preceding claims, in which the or each said tubular member is circular in cross section.

14. The structure of any one of Claims 1 to 7, further including means to locate said female member and said nipple circumferentially in a predetermined relative orientation.

15. Apparatus for use in sub-surface investigations in geological formations, in which apparatus a plurality of longitudinally aligned tubulars is assembled and is coupled together in end-to-end fashion by a coupling arrangement comprising: tubulars each having at each end thereof an unthreaded nipple portion of reduced diameter divided by longitudinal slots into a plurality of inwardly-deflectable springy segments; ori each nipple portion a segmental shoulder formed of lugs extending circumferentially about the end of the nipple portion; a coupling sleeve having oppositely directed sockets to receive the nipple portions of a pair of tubulars disposed end-to-end; said sleeve having a cylindrical recess located in the mid-portion of its inner wall and including a double-ended orienting boss affixed in said recess;; the nipple portions of said tubulars having notches to engage said double-ended boss and thereby to limit their inward incursion within said sleeve and to fixedly orient said tubulars; and circumferentially spaced longitudinal internal grooves in said tubulars all having like relationship to said notches for assembly in alignment to form continuous uninterrupted tracks for probes to move longitudinally within said apparatus.

16. A coupling arrangement between two aligned tubular members, or between a tubular member and a female member, substantially as specifically described herein with reference to Figs. 1 to 4 and 6 or to Fig. 5 of the accompanying drawings.

17. An assembly of aligned tubular conduit members, in which at least two adjacent tubular conduit members are connected together by a coupling arrangement as claimed in any one of Claims 1 to 16.

CLAIMS (7 Aug 1984)

1. For use in a tubular conduit system, a coupling between adjacent ends of two aligned tubular conduit members, comprising an unthreaded nipple portion at the said end of each tubular conduit member, the nipple portion being formed with inwardly-deflectable integral springy segments having shouldered external lugs, and a tubular coupling sleeve having communicating sockets respectively opening through its opposite ends to receive respectively the nipple portions of the two tubular conduit members when said members are disposed endto-end in axial alignment, each socket being adapted to receive and deflect the segments of the respctive nipple portion inwardly when the nipple portion is introduced into the socket, and there being a circumferential shouldered recess in the tubular sleeve to receive and interlock with the shouldered lugs of the segments so as to secure the tubular conduit member to the sleeve when the nipple portion is fully inserted into the socket, whereby the two tubular conduit members can be secured and couple together by the sleeve in end-to-end axial alignment and in which the two tubular conduit members have like internal longitudinal grooves similarlydisposed in their walls, and the coupling includes alignments means within the tubular sleeve which cooperates with formations on the adjacent ends of the tubular conduit members to effect and maintain alignment of the longitudinal grooves of the two tubular conduit members when so coupled together by the coupling.

2. A coupling as claimed in Claim 1, in which the alignment means comprises a doubleended boss wall-mounted within the sleeve, and in which the nipple portion of each tubular conduit member has a notch to receive and locate with a respective end of the boss to align the conduit member circumferentially with respect to the sleeve when the nipple portion is fully inserted into the socket.

3. A coupling as claimed in Claim 1 or Claim 2, in which when the nipple portions of the two tubular conduit members are fully inserted in the respective sockets, the shouldered lugs of both nipple portions are received in and interlock with one and the same shouldered recess in the sleeve and the outer extremities of the two nipple portions are closely opposed to one another.

4. A coupling as claimed in any one of Claims 1 to 3, in which the shouldered lugs on the inwardly deflectable segments of each nipple portion together constitute a segmental shouldered external collar extending at least partially around the nipple portion.

5. A coupling as claimed in Claim 4, in which the segmental shouldered collar extends circumferentially around the end of the nipple portion, and the sleeve includes a cylindrical shouldered recess to receive and interlock with the segmental shouldered collar.

6. A coupling as claimed in any one of Claims 1 to 5, in which each nipple portion is divided by slots in its wall into at least three segments.

7. A coupling as claimed in Claim 6, in which each nipple portion is divided into segments by narrow slots each extending parallel to the nipple axis from the outer extremity of the nipple portion and terminating at a location spaced-apart from the inner extremity of the nipple portion.

8. A coupling as claimed in any one of Claims 1 to 7, including annular fluid seal means between each nipple portion and the socket with which it is associated.

9. A coupling as claimed in any one of the preceding claims, in which each said tubular member is circular in cross section.

10. Apparatus for use in sub-surface investigations in geological formations, in which apparatus a plurality of longitudinally aligned tubular conduit members is assembled and is coupled together in end-to-end fashion by a coupling comprising: tubular conduit members each having at each end thereof an unthreaded nipple portion of reduced diameter divided by longitudinal slots into a plurality of inwardly-deflectable springy segments; on each nipple portion a segmental shoulder formed of lugs extending circumferentially about the end of the nipple portion; a coupling sleeve having oppositely directed sockets to receive the nipple portions of a pair of tubulars disposed end-to-end;; said sleeve having a circumferentially-shouldered cylindrical recess located in the mid-portion of its inner wall to receive and interlock with the lugs of the two nipple portions and including a double-end orienting boss affixed in said recess; the nipple portions of said tubular conduit members having notches to engage said doubleend boss and thereby to limit their inward incursion within said sleeve and to fixedly orient said tubular conduit members; and circumferentially spaced longitudinal internal grooves in said tubular conduit members all having like relationship to said notches for location in alignment by the engagement of said notches with the boss to form continuous uninterrupted tracks in the assembly of tubular conduit members for probes to move longitudinally within said apparatus.

11. A coupling between two aligned tubular members, substantially as specifically described herein with reference to Figs. 1 to 4 and 6 of the accompanying drawings.