US3136366A

US3136366A - Coupling devices

Info

Publication number: US3136366A
Application number: US756552A
Authority: US
Inventors: Cicero C Brown; Chudleigh B Cochran
Original assignee: Individual
Current assignee: Individual
Priority date: 1958-08-22
Filing date: 1958-08-22
Publication date: 1964-06-09
Anticipated expiration: 1981-06-09

Description

n 1954 c. c. BROWN ETAL COUPLING DEVICES 5 Sheets-Sheet 1 Filed Aug. 22, 1958 C/CZAO C. BROWN CHUflZi/fl B. CWCIAA/V INVENTORS d W jfl) g, 27, JAN #1 ATTORNEYS June 9, 1964 c. c. BROWN ETAL 3,136,366

COUPLING DEVICES Filed Aug. 22, 1958 5 Sheets-Sheet 2 0A0 AVA INV EN TORS MOI W BY 2 550m 3,, 9W

n 9, 1964 c. c. BROWN ETAL COUPLING DEVICES 5 Sheets-Sheet 3 Filed Aug. 22, 1958 June 9, 1964 c. c. BROWN ETAL 3,136,366

COUPLING DEVICES Filed Aug. 22, 1958 5 Sheets-Sheet 4 C/CfRO C. 5R0 W/V CHI/0i [/Gl/ B. CDC/IRAN INVENTORS Mal/JUL BY E! in, 3/14 ATTORNEYS June 9, 1964 Filed Au 22, 1958 c. 0. BROWN ETAL 3,136,366

COUPLING DEVICES 5 Sheets-Sheet 5 Ilka.

C/CERO C. BROWN CHUDLE/Gl/ a. COCHRAN INVENTORJ' WM BY gm) g Eva/v14;

ATTORNEYS United States Patent 3,136,366 COUPLING DEVICES Cicero C. Brown, 8490 Katy Road, Houston, Tex., and Chudlcigh B. Cochran, Houston, Tex; said Cochran assignor to said Brown Filed Aug. 22, 1958, Ser. No. 756,552 3 Claims. (Cl. 166-181) This invention relates to new and useful improvements in coupling devices.

In various types of well apparatus, it is desirable to couple or latch a tubular conductor to a particular tool or to another conductor and to subsequently effect a re lease of said connection. For example, in multiple well production apparatus, it has become the practice to run the multiple strings of well tubing separately of each other and as each string is finally landed, its lower end is connected or coupled to a well packer or some other device to establish communication with the desired area; when subsequent removal of the string is necessary, the connection must, of course, be releasable. Obviously, while in connected position the coupling arrangement must be such that it will not be unintentionally or prematurely disconnected either by well pressure from below or by other causes. Also since well tubing or conductor strings extend for considerable distances in the order of several thousands of feet, it is desirable that the coupling device be engageable and disengageable by a straight longitudinal movement of the conductor and without the necessity of rotating orotherwise manipulating said conductor.

It is, therefore, one object of this invention to provide an improved coupling device for releasably coupling two members to each other, with said device being engageable to coupled position and disengageable from coupled positionby a straight line movement of the coupling members.

An important object is to'provide a coupling device including complementary members which are adapted to be engaged with each other and latched in such engaged or connected position; the latching arrangement being such that disconnection of said members can be accomplished by an outward pull of predetermined force upon one of said members whereby premature or unintentional separation of said members is obviated.

A further object is to provide a coupling device which is particularly adapted for use in coupling a well conductor to a well tool and which is so constructed that when in connected position, any pressure within the well bore which would tend to separate the coupling members is utilized to cause the members to engage more firmly, whereby the danger of well pressures effecting a disengagement of the coupling device is eliminated.

Still another object is to provide a coupling of the character described wherein the coupling members are connected by relative longitudinal movement and are automatically latched in such connected position; the members being releasable from such latched position by the equalization of pressures and the application of a predetermined force in one direction upon one of said members, which force is by movement of the member longitudinally with respect to the other member, whereby rotation of either member of said device is not necessary to connect or disconnect said members.

The construction designed to carry out the invention will be hereinafter described, together with other features thereof.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings forming a part thereof, wherein an example of the invention is shown, and

wherein: n

FIGURE 1 is a view partly in elevation and partly in 3,136,366 Patented June 9, 1964 section of a coupling device constructed in accordance with the invention and illustrating the coupling members being moved toward coupled position;

FIGURE 2 is a similar view illustrating the members in fully coupled position;

FIGURES 3 and 4 are schematic views illustrating one use of the improved coupling device;

FIGURE 5 is a schematic view illustrating another use of said device;

FIGURE 6 is a view partly in section and partly in elevation of a modified form of the invention;

FIGURE 7 is a similar View illustrating still another form of the invention;

FIGURE 8 is a view partly in section and partly in elevation of a modification of the device wherein gripping elements are substituted for the locking dogs;

FIGURE 9 is a view partly in section and partly in elevation of still another form of the coupling device and showing the inner member being moved into position within the outer member;

FIGURE 10 is a view similar to FIGURE 6 showing the members in fully coupled position,

FIGURE 11 is a horizontal cross-sectional view taken on the line 11-11 of FIGURE 9,

FIGURE 12 is a horizontal cross-sectional view taken on the line 1212 of FIGURE 10; and

FIGURE 13 is an isometric view of the inner member of the modification of FIGURE 9 with portions thereof shown in section.

Inthe drawings (FIGURES 1 and 2) the letter A designates an outer coupling member which may take the form of a housing or casing having a longitudinal bore 10 extending therethrough. An annular locking recess 11 is formed within the bore and said recess is defined by a straight wall section 11a, an upper beveled surface 12 and a lower beveled surface 13. An inclined guide surface 14 is preferably formed at the upper end of the outer housing member A.

An inner member generally indicated by the letter B is insertable and slidable within the bore 10 of the outer housing member and, as will be explained, is adapted to be moved into a coupled or connected position by a straight-line movement of the inner member B longitudinally with respect to the outer member A. When in coupled position, latching elements or locking dogs 15 carried bythe inner member B engage within the locking recess 11 in the manner illustrated in FIGURE 2, and upward movement of the inner member B with respect to the outer member is prevented. However, as will hereinafter appear, the inner member may be disconnectedv from the outer member by a straight-line longitudinal pullingv force applied to the outer end of the inner member B, which force will result in a suflicient retraction of the latching dogs 15 to permit separation of the members A andB. Thus, the coupling device provides inner and outer members which may be connected by a straight-line longitudinal movement of the inner member with respect to the outer member to telescope the member and automatically latch the same in connected position; release of the latching means and separation of the members is effected by the application of a pulling force, preferably to the outer end of the inner member. 7

As is clearly shown in FIGURES 1 and 2, the inner member B comprises a tubular mandrel or support 16 which may ,have its upper end connected to a tubular pipe or conductor 17. Below the cennection with the pipe, an annular packing assembly 18, including suitable packing rings, surrounds the mandrel and functions to seal with the bore 10 of the outer member when the members are in connected position. The packing. rings of the I assembly 18 are retained in position by a retaining collar 3 19 which is threaded onto the outer surface of the mandrel 16.

An external annular shoulder 20 is formed on the mandrel and is spaced below the collar 19 and said shoulder functions to support the locking dogs 15. As illustrated,

longitudinal slots 21 are cut in a sleeve 22 which surrounds the mandrel, and the portions between the slots comprise the latching elements or dogs 15. An internal supporting shoulder 23 within the sleeve 22 normally engages the external shoulder Zll on the mandrel to suspend the latching dogs 15 from said mandrel. By forming said latching dogs in the manner shown, a very simple construction is provided and it is evident that each dog 15 may undergo limited radial movement with respect to the mandreltthe inherent resiliency of the metal of the sleeve member 22 tends to urge the dogs outwardly in a radial direction.

Each latching or looking dog 15 has an external inclined shoulder 24 thereon, while thelower portion of the inner surface of each dog is also'inclined as shown at 25. It is noted that the angle of the'shoulder 24 is substantially complementary to the angle of the bevel 12 which defines the upper end of the locking recess and this angle is different than the angle 25 on the inner surface of each locking dog. As illustrated, the angle of inclination of the surface 25 is a steeper angle with respect to a plane through the axis of member B than is the angle of inclination of the surface 24.

Spaced downwardly from the external supporting shoulder 20 is another external shoulder 26 which is formed on the exterior surface of the mandrel 16. An expander sleeve 27 is slidable on the lower portion of the tubular mandrel 16 below the shoulder 26 and the upper end of said sleeve has an inclined expander surface 28 which, as will be explained, co-acts with the inclined inner surface 25 of the latching elements or dogs 15. The sleeve 27 substantially fills the annular space between the mandrel 16 and the bore of the outer member A when the member B is inserted into the latter and a suitable seal 29, such as an O-ring, seals off between the bore of the sleeve and the exterior of the mandrel; a similar sealing ring 30 effects a seal between the exterior of the sleeve 27 and the bore 10. Thus, when the inner member is positioned within the bore 10 of the outer member, the sleeve 27, in effect, forms a piston which has its lower end exposed to the pressure within the members and particularly to the pressure in the area below the inner member.

For normally maintaining the expander sleeve 27 in a position engaging the stop shoulder 26, a coil spring 31 acts against the lower end of the sleeve and is confined between such lower end and an enlarged collar 32 which is threaded onto the lower end of the mandrel 16. It is evident that the spring 31 constantly exerts its pressure to urge the expander sleeve upwardly relative to the mandrel 16.

In the operation of the improved coupling device, the outer housing member A is attached to a conductor (not shown) and where the coupling is used in a well, the housing would be located within the well bore. The inner member B, which is to be coupled with the housing member A, is attached to the lower end of the conductor or pipe 17 and is lowered downwardly within the well bore. During the lowering, the latch elements or locking dogs will be in their outer radial position and may either be suspended from the supporting shoulder or may be slid upwardly by reason of pressure acting thereagainst during lowering so that the upper end of the latching sleeve 22 engages the under side of the retaining collar 19. At this time the coil spring 31 is maintaining the expander sleeve 27 in its raised position with respect to the mandrel and in engagement with the stop shoulder 26.

The collar 32 at the lower end of the mandrel has its lower peripheral edge portion beveled as shown at 32a so that as the inner member B is lowered into the outer member A, this surface will co-act with the inclined guide surface 14 at the upper end of member A to guide the inner member into the bore 1%) of said outer member. As lowering of the inner member into the bore continues, the lower beveled ends 24a of the latching elements or dogs 15 also contact the inclined surface 14- and such coaction results in moving the elements or dogs inwardly whereby they may enter the bore lit in the manner illustrated in FIGURE 1. As the inner member B moves downwardly through the bore, the latching elements drag on the inner surface of the bore 11), and the parts assume the position substantially as shown in FIGURE 1.

Lowering of the inner member B is continued until the latching elements or dogs 15 move opposite the locking recess 12 and at this time the inherent resiliency of said dogs causes the same to expand outwardly into said recess. The inner member may thereafter be lifted upwardly, and such upward movement will cause the parts to as sume the position shown in FIGURE 2 with the inclined surface 28 of the expander sleeve 27 engaging the inclined inner surfaces 25 of the latching elements. It is thus obvious that the latching elements or dogs are confined between the inclined surface 28 of the expander sleeve and are maintained in tight abutting contact with the beveled shoulder 12 which defines the upper end of the locking recess. The device is now in latched position to prevent an upward displacement of the inner member B from the outer member A.

The coil spring 31 is, of course, acting at all times to maintain the expander sleeve 27 against the latching elements or dogs 15 to prevent inward radial movement thereof. In addition, the pressure below the inner member B, which might normally tend to move the mandrel 16 upwardly and possibly cause a disconnection of the coupling device, is directed against the lower surface of the piston-like expander sleeve 27 and such pressure constantly urges the expander sleeve upwardly to increase the locking action of the elements 15 within the recess 11. Thus, once the device is coupled by the straight longitudinal movement of the inner member with respect to the outer member, it is maintained in connected position and the inner member can not be displaced upwardly by excessive pressure therebelow.

It is noted that since the inner member B is suspended from the pipe 17, it is supported against downward movement within the outer member A. Thus, disconnection of the members would be caused by an unintentional upward movement of the inner member relative to the outer a pulling force is applied to the upper or outer end of the mandrel 16 by pulling upwardly on the conductor or pipe 17 which is connected thereto. The pulling force applied to the mandrel is transmitted through the support shoulder 20 to the latching sleeve 22 and to the latching elements or dogs 15 which form a part thereof. As this upward pulling force is applied to the latching elements, the co-action between the

inclined surfaces

12 and 24 of the recesses and latching elements respectively, sets up a resultant force which tends to urge the latching elements or dogs radially inwardly. This tendency toward inward movement of the dogs is resisted by the engagement of the inclined surface 25 of each'element with the inclined surface 28 of the expander sleeve. However, because of the difference in angles, a predetermined pulling force applied to the latching elements will finally develop a sufficient resultant force to cause the expander sleeve to be moved downwardly under tension of the spring 31. In other words, an annular squeezing action is applied to the inclined expander sleeve 27 and when this force is sufiicient, the sleeve is moved downwardly a sufficient distance to allow inward movement of the latching elements or dogs whereby said dogs will clear the shoulder 12, after which the inner member B may be removed. Obviously, such removal is effected by a straight-line longitudinal pull applied to the inner member.

It is pointed out that by changing the angles of the

surfaces

24 and 25 on the latching elements or dogs, the force necessary to displace the expander sleeve downwardly can be controlled. It might also be noted that if there is excessive pressure acting against the lower end of the expander sleeve 27 at the time that removal is desired, such pressure may be relieved in any desired manner such as manipulating a valve or control in the upper end of the conductor 17, or suitable pressure may be applied outside of the inner member to act against the upper end of the expander sleeve 27 to equalize pressures thereacross.

The coupling element may be employed wherever desired and although unlatching and removal of the inner member has been described as being effected by a pull upon the end of the inner member B, it is evident that a downward pull on member A would effect the same result. Where the device is employed within a well bore, the outer housing member A would be anchored within the bore and disconnection would be effected as described. However, when used in other installations in which the outer housing member A may undergo movement, unlatchingand disconnection may be accomplished by movement of the outer member in the proper direction with respect to the inner member. So long as the proper force is applied to the inclined surface 24 of the latching element, uncoupling may be accomplished.

In FIGURES 3 and 4, one use of the improved coupling device with multiple packers is illustrated. As shown in FIGURE 3, three packers P1, P2 and P3, are adapted to be run into the well bore W on a tubing string T1 and are positioned to separate the production from three producing formations F1, F2 and F3. As illustrated, a second tubing string T2 is adapted to be connected through a J-slot or other releasable connection I with the upper packer P3 and a pipe section T3 has its upper end connected with packer P3 and extended downwardly for connection with the packer P2. The outer housing A of the coupling device is located in the packer P2 while the inner member B is mounted on the lower end of the section T3 to make the connection.

In the use of the apparatus shown in FIGURE 3, the three packers P1, P2 and P3 are run on the string T1, which string has a safety joint S disposed between the packers P2 and P3. At the time that the packers are run, the connecting section T3 is placed in position connecting packers P2 and P3 in the manner shown. After the packers are in proper position, the second tubing string T2 is then lowered and coupled through the J-slot I with the uppermost packer P3. In this type of installation a third tubing string (not shown) is also connected with the upper packer to conduct the pressure fluids from the upper formation F3 to the surface. It will be evident that production from the formation F1 is through tubing T1 with production from formation F2 through tubing T2.

When the assembly is to be removed, the tubing string T2, as well as the third tubing string (not shown) are removed from the well. The tubing T1 is then rotated to disconnect the safety joint S in the manner illustrated in FIGURE 4 and this disconnects the upper packer P3 from the intermediate packer P2. At this time it is essential that a straight longitudinal lifting onpipe T2 will result in a disconnection of the connecting section T3 with the intermediate packer. By utilizing the coupling device of this invention as the connecting means between the section T3 and packer P2, release may be accomplished by such straight line motion.

In FIGURE 5, use of the improved coupling device with dual packers is schematically shown. In this figure the well bore W is illustrated as having a lower Well packer P4 set therein. An upper well packer P5 is also set within the bore in spaced relationship to the lower packer and said packers pack-off between the lower producing formation F1 and the intermediate producing formation F2. A well tubing T4 is attached to both packers P4 and P5 and functions to lower the packers into position within the bore. The upper packer is formed with the outer housing A having the longitudinal bore 10 therein. The inner member B is secured to the lower portion of a second tubing string T5 and is utilized to couple the second tubing string in position.

In the type of installation shown in FIGURE 5, packers P4 and P5 are lowered by means of a first tubing string T4 and are properly located in position. Thereafter, the second string T5 is run independently and its lower end must be ocupled and packed off with the upper packer. It is evident that the particular coupling device is especially adapted for this use because it permits coupling of the second tubing string with the upper packer by a straight longitudinal movement requiring no rotation. After being coupled in position, any pressure acting to displace the inner member B and string T5 upwardly will merely serve to increase the latching action of the dogs 15. However, when desired, the inner member B may be readily disconnected by applying a predetermined pulling force through tubing T5. Therefore, disconnection is accomplished by a straight longitudinal pull which releases the latching elements and allows removal of the second tubing string 41.

In FIGURE 6 a slightly modified form of the invention is shown. In this form the tubular mandrel 16 has the packing assembly 18 and the latching sleeve 22 mounted thereon in the same manner as the form of FIGURE 1. However, the expander sleeve 27 is eliminated and in place thereof an expander collar 27a is provided. This collar is relatively short and has no seals, similar to the sealing rings 29 and 30. The coil spring 31 acts against the collar 27 to urge the same upwardly. In this form of the invention the strength of the coil spring is relied upon to maintain the expander surface 28a in contact with the rear surface 25 of the latching elements 15. By making this spring of sufiicient strength, the latching dogs will be retained in position until such time as a predetermined pulling force is applied to the upper or outer end of the mandrel 16. Except for the fact that the expander 'collar 27a is not acted upon by pressure from below, the operation of this form of the invention is the same as the operation of the form shown in FIGURES l and 2.

In FIGURE 7 another modification is illustrated and this modification operates in substantially the same manner as the form of FIGURE 1. However, in this case a packing assembly 18a, instead of being located above the latching elements 15, is located below such elements. The packing assembly 13a will not only seal with the bore 11) of the outer member A but will also take the place of the sealing rings 29 and 30, whereby the expander sleeve 27b of this form is pressure actuated.

Briefly, the modification of FIGURE 7 includes a modified mandrel 16a having a support shoulder 20a from which is suspended the latching sleeve 22 having the latching dogs 15. The expander sleeve 27b is slidable upon the mandrel 16a below the dogs 15 and has the packing assembly 18a at its lower end. The coil spring 31 acts on the lower end of the expander 27b and the operation is substantially identical to the operation of the form of FIGURE 1.

In the forms of the invention illustrated in FIGURES 1, 2, 6 and 7, the latching means is in the form of a latching element or dog which is adapted to engage within a locking recess 10 of the outer housing A. It has been found that the coupling device can be operated without the inclusion of the locking recess and in FIGURE 8 such a modification is illustrated. Referring to FIGURE 8, an outer housing A, which has a smooth bore 10a extending entirely therethrough, is provided and this housing forms the outer member of the coupling device. The inner member B of this form of the invention is constructed in substantially the same manner as the inner member B of FIGURE 1 except that gripping e1..- ments or slips 215 having external teeth are substituted for the latching dogs 15 shown in FIGURE 1. The inner member B includes the central mandrel 16, the packing assembly 18, the supporting shoulder 29, the piston sleeve 27, spring 31 and retaining collar 32. In place of the latching sleeve 22, a latching sleeve 222 is provided, this sleeve being slotted at 221 with the portions between the slots forming the gripping elements or slips 215. The outer surface of the lower portion of each gripping element is provided with gripping teeth 215a which are adapted to engage the smooth bore lila of the outer housing or member A.

In operation the inner member B is lowered into the bore of the outer member and upon upward movement of the mandrel, the teeth 215a of the gripping slips 215 are caused to engage the wall of the bore 10a of the outer member (FIGURE 8). Any pressure which would tend to separate the members and acting below the pis ton sleeve 27 merely urges theslips into tighter gripping position.

In order torelease the connection between the members, an upward pull on the inner member B will first cause the teeth 215a of the gripping elements to become more firmly imbedded in the wall of the bore and, in effect, the uppermost tooth will form a shoulder which might be said to be similar to the upper shoulder 12 of the locking recess 19 of the first form. Thereafter, the inclined rear surface 21512 of each latching slip 215 will coact with the inclined surface 28 at the upper end of the piston sleeve 27 to develop a resultant force sumcient to applyan annular squeezing action to the upper end of sleeve 27. When this force is sufficient to overcome the spring 31, the sleeve 2'7 is moved downwardly against tension of the spring to allow a sufficient inward movement of the slip members to permit their disengagement from the wall of the bore.

In FIGURES 9 and 10, still another modification of the invention is illustrated. An outer housing A2 is formed with a locking recess 11 nearer its upper end. An inner member B2 includes a tubular mandrel 116 which is formed with a plurality of radially extending slots 42 within which radially movable latching elements 115 are mounted. Complete outward displacement of each element 115 from its respective slot is prevented by the lugs 115 (FIGURE 11) which are formed on each element at the top and bottom thereof and which are adapted to engage within an annular recessed portion 116b of the inner wall surface of the mandrel 116 to limit outward movement of said element. Each latching element has an inward projection 115a at its upper end and a similar projection 115k at its lower end. These formed on an internal actuating sleeve 44 which is slidable within the bore 116a of the mandrel 116. A heavy coil spring 45 normally holds the control sleeve 44 in a lowered position abutting the upper end 46 of a coupling member 47 which is secured to the lower end of the mandrel 116 and which carries a suitable packing as sembly 118.

In the operation of this form, the coil spring 45 normally maintains the control sleeve 44 in the position shown in FIGURE 9. In such position the outward projection 43 on the control sleeve 44 is located between the projections 115a and 11511 of each latch element 115, whereby said latch elements are located in their inward radial position. The inner member B2 is movable inwardly of the outer member A2 until an external shoulder 48 on the mandrel 116 engages the inclined upper surface 14a of the outer member which is the position shown in FIGURE 10. This stops further inward movement of the mandrel 116 and aligns the latching or locking elepro ections are adapted to co-act with a pro ection 43 8 ments with the locking recess 11 in the member A2.

The cross-sectional area C at the lower end of the control sleeve is larger than the cross-sectional area D at the upper end of the member and, therefore, any pressure within the bore of the members will act to move the control sleeve 44 upwardly to the position shown in FIGURE 10. In this position the projection 43 on the control sleeve moves behind the upper projection 115a of each locking element and the larger surface 43a at the lower end of the lockingsleeve moves behind the projection 11%. This position of the parts is illustrated in FIGURE 10 and so long as the control sleeve remains in such position, the locking elements can not be retracted.

When it is desired to retract the locking elements 115 to uncouple the members, the pressure within the memhers is relieved or pressure is built up exteriorly of the member B2 so that it may pass downwardly into the bore 10 of the outer member A2 and equalize the pressures across the control sleeve 44. Upon equalization of pressures, the spring 45 will return the control sleeve to the position of FIGURE 9 which permits retraction of the locking elements.

The foregoing disclosure and description of the inven- ,tion is illustrative and explanatory thereof and various changes in size, shape and materials, as well as in the details of the illustrated construction, may be made within the scope of the appended claims without departing from the spirit of the invention.

What we claim is: 1. A coupling device for use with a well conductor including,

an outer tubular housing member having a locking recess therein, an inner coupling member insertable within said outer housing member and comprising a mandrel, said mandrel being connected to said conductor so that an upward pull on said conductor imparts an upward pull to said mandrel, a latch element carried by the mandrel and movable radially thereof, said latch element being engageable within the locking recess when the inner member is within the housing member, a sleeve slidable relative to the mandrel and latch element for urging the latch element outwardly, means for urging the sleeve in a direction to maintain the latch element within said recess, and cam surfaces on the latching element and sleeve actuated by the application of a predetermined pulling force upon the conductor and mandrel for releasing the latch element from the locking recess to permit separation of the inner and outer members. 2. A coupling device as set forth in claim 1, wherein the urging means for said sleeve is a spring of predetermined strength. 3. A coupling device as set forth in claim 1, wherein the urging means for said sleeve comprises a surface on said sleeve exposed to the pressure within the coupled members which pressure thereby acts upon said surface and said sleeve.

References Cited in the file of this patent UNITED STATES PATENTS

Claims

1. A COUPLING DEVICE FOR USE WITH A WELL CONDUCTOR INCLUDING, AN OUTER TUBULAR HOUSING MEMBER HAVING A LOCKING RECESS THEREIN, AN INNER COUPLING MEMBER INSERTABLE WITHIN SAID OUTER HOUSING MEMBER AND COMPRISING A MANDREL, SAID MANDREL BEING CONNECTED TO SAID CONDUCTOR SO THAT AN UPWARD PULL ON SAID CONDUCTOR IMPARTS AN UPWARD PULL TO SAID MANDREL, A LATCH ELEMENT CARRIED BY THE MANDREL AND MOVABLE RADIALLY THEREOF, SAID LATCH ELEMENT BEING ENGAGEABLE WITHIN THE LOCKING RECESS WHEN THE INNER MEMBER IS WITHIN THE HOUSING MEMBER, A SLEEVE SLIDABLE RELATIVE TO THE MANDREL AND LATCH ELEMENT FOR URGING THE LATCH ELEMENT OUTWARDLY, MEANS FOR URGING THE SLEEVE IN A DIRECTION TO MAINTAIN THE LATCH ELEMENT WITHIN SAID RECESS, AND CAM SURFACES ON THE LATCHING ELEMENT AND SLEEVE ACTUATED BY THE APPLICATION OF A PREDETERMINED PULLING FORCE UPON THE CONDUCTOR AND MANDREL FOR RELEASING THE LATCH ELEMENT FROM THE LOCKING RECESS TO PERMIT SEPARATION OF THE INNER AND OUTER MEMBERS.