US3391742A

US3391742A - Releasable well packer

Info

Publication number: US3391742A
Application number: US553455A
Authority: US
Inventors: John B Davis
Original assignee: Brown Oil Tools Inc
Current assignee: Hughes Tool Co
Priority date: 1966-05-27
Filing date: 1966-05-27
Publication date: 1968-07-09
Anticipated expiration: 1985-07-09

Description

July 9, 1968 J. B. DAVIS 3,391,742

RELEASABLE WELL PACKER Filed May 27, 1966 3 Sheets-Sheet 1 BY lu 25 511W ATTORNEYS July 9, 1968 J. B. DAVIS 3,391,742

RELEASABLE WELL PACKER Filed May 27, 1966 3 Sheets-Sheet 2 dab 1V8. D V/S 1N VENT R.

J. B. DAVIS July 9, 1968 RELEASABLE WELL PACKER 3 Sheets-Sheet3 Filed May 27. 1966 w/525536 83. y, W BY? QM ATTORNEIS United States Patent 01 ice 3,391,742 RELEASABLE WELL PACKER John B. Davis, Houston, Tex., assignor to Brown Oil Tools, Inc., Houston, Tex., a corporation of Texas Filed May 27, 1966, Ser. No. 553,455 13 Claims. (Cl. 166-139) The present invention relates to new and useful improvements in well packers.

The invention is applicable for use in anchoring well devices, such as well packers and the like, or well tubing within the bore of the well and is suitable for use in high-temperature applications.

Well packers which are exposed to high temperatures, such as encountered in steam injection, are subject to considerable elongation of the component parts because of the heating of such parts. This elongation may result in the failure of the seal of the packing assembly or, in extreme cases, may be suflicient to at least partially release the anchoring assembly.

An important object of the present invention is to provide an improved well packer suitable for use under conditions of high temperature.

Another object is to provide an improved well packer which will, when set, hold against longitudinal movement in both directions and is readily releasable upon upward pull on the tubing string on which it is mounted.

A further object is to provide. a well packer which is adapted to be set in a well bore and released by a manipulation of the tubing string on which it is mounted and which, after being set and released, may be reset without removal from the well bore.

Another object is to provide a well packer with a setting means which may be actuated for setting by rotation of the tubing string and for releasing by lifting of the tubing string.

Still another object is to provide a new and improved mechanically set and releasable well packer having provision for equalizing pressure across the packing assembly to assure release.

A still further object is to provide a new and improved well packer slidably mounted on a tubular support which is set by rotation of such tubular support and released by lifting such tubular support.

Other objects, features and advantages will be apparent from the drawings, the specification and the claims.

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:

FIGURE 1 is a partial longitudinal sectional view of one form of the well packer of the present invention in position within a well bore ready for setting;

FIGURE 2 is a similar view of the well packer of FIGURE 1 in set position;

FIGURE 3 is another similar view of the well packer of FIGURE 1 illustrating the position for equalizing pressure across the packing assembly by manipulation of the tubing string supporting the well packer;

FIGURE 4 is another partial longitudinal sectional view of the well packer of FIGURE 1 and showing the release thereof;

FIGURE 5 is a partial longitudinal sectional view of a modified form of well packer in position within a well bore ready for setting;

FIGURE 6 is a transverse sectional view taken along line 6--6 in FIGURE 1; and

3,391,742 Patented July 9, 1968 FIGURE 7 is a transverse sectional view taken along line 7-7 in FIGURE 1.

Referring more in detail to the drawings, the well packer as illustrated in FIGURE 1 is shown in running position. The well packer is secured to the tubing string T for lowering into the well bore defined by the casing C. The tubing string T is connected to the well packer by the coupling 10. The well packer includes the inner tubular support or mandrel 12 and the outer tubular support or mandrel 14 with the packing assembly P. the anchoring assembly A and the setting means S mounted in surrounding relationship thereto. Both

tubular supports

12 and 14 are secured to the coupling 10. The packing assembly P, the anchoring assembly A and the setting means S are all free of direct attachment to the

mandrels

12 and 14 to allow the mandrels to be moved longitudinally therethrough.

The setting means S is adapted to provide a relative setting movement of the packing assembly P and the anchoring assembly A. For this reason, the setting means S is connected to provide an abutment for the upper end of the packing assembly P and is releasably engaged with the lower end of the anchoring assembly A to provide a lower abutment therefor. The setting means S includes the inner setting sleeve 16 and the outer setting sleeve 18 which are in threaded engagement with each other. The outer setting sleve 18 is in releasable engagement with the lower end of anchoring assembly A as hereinafter more fully described.

The inner setting sleeve 16 is connected to the ring 26 which, in turn, is connected to the collar 22. The

shoulder 24 on the upper exterior of inner setting sleeve 16 is adapted to engage the inner shoulder 26 on the packing sleeve 28 to retain the packing sleeve 28 in position in relation to collar 22. Abutment ring 30 is secured to collar 22 to provide the upper abutment for the packing assembly P. Packing 32 is provided to seal between ring 20 and the exterior of outer mandrel 14. Packing 34 is provided to seal between ring 20 and packing sleeve 28.

The packing assembly P, as shown, is designed to expand radially outward when subjected to an endwise setting force. The packing elements 36 of the packing assembly P are of suitable configuration and material to provide a seal, when set, against the interior of casing C and to withstand high temperatures such as are encountered in steam injection operations. The packing assembly P includes an upper reinforcing ring 38 and a lower reinforcing ring 40. The

rings

38 and 40 are mounted around the packing sleeve 28, as shown, with the packing elements 36 between such rings. The shoulder 42 on the lower exterior of packing sleeve 28 is adapted to engage the lower surface of ring 40 when the packing assembly P is relaxed to retain the

rings

38 and 40 and the packing elements 36 in position on the packing sleeve 28.

The anchoring assembly A is mounted surrounding the outer setting sleeve 18 and immediately below the packing assembly P. The anchoring assembly A includes a cage 42, a plurality of gripping slips 44, an upper expander 46 and a lower expander 48. As best seen in FIGURE 6, the gripping slips 44 are adapted to be moved outward through the windows in cage 42 into pipe-gripping engagement with the interior of easing C responsive to the wedging action of the

expanders

46 and 48 when such expanders are moved toward each other. The upper expander 46 is secured to the lower reinforcing ring 40 of packing assembly P. Means is provided to prevent rotation of the anchoring assembly A and the sleeve 18 within the casing C. Such means includes the springs 50, which are secured to the exterior of cage 42 by screws 52, and are formed to have a sufficient bow to engage the casing C. Relative rotation of the parts of the anchoring assembly A is prevented by the pins 54, which are threaded into lower expander 48 and project outward therefrom into the vertical slots 56 in cage 42, and the pins 58, which are threaded through upper expander 46 and project out into the vertical slots 60 in cage 42. The pins 58 also project inward from upper expander 46 into the slots 62 in outer setting sleeve 18 so that the sleeve 18 also is prevented from rotating during actuation of the setting means S.

The outer setting sleeve 18 includes a plurality of release fingers 64 depending from its lower edge to provide a releasable connection to lower expander 48, as hereinafter more fully explained. The release ring 66 is positioned around outer tubular support 14 and in engagement with the inner surface of the lower end of the fingers 64. The engagement between release ring 66 and the fingers 64 is made releasable by the shear pins 68, as best seen in FIG- URE 7. In running position the shoulders 70 on the fingers 64 engage against the shoulder 72 on lower expander 48. The outer setting sleeve 18 includes the inward projections 74. The inner surface of projection 74 is spaced radially from outer tubular support 14 a distance less than the thickness of the upper end of release ring 66.

Sleeve 75 is releasably connected to lower expander 48 and in running position of the well packer engages the lower end of fingers 64 to cooperate with the shoulder 72 on lower expander 48, thus retaining or holding the fingers 64 in running position. This retention of the enlarged lower end of the fingers 64 by the shoulder 72, the sleeve 75 and release ring 66 provides a connection spanning the packing assembly P and the anchoring assembly A to prevent inadvertent setting of either assembly in the running of the well packer into a well bore.

The pins 76 are secured in the sleeve 75 and extend inwardly therefrom to provide a means of preventing inadvertent release and to allow the tubing string to be manipulated to equalize pressure across the packing assembly P when desired. The grooved collar 78 is provided with external grooves 80 which are adapted to receive the pins 76, as hereinafter explained. The grooved collar 78 is secured to the lower end of the outer tubular support 14. The inner surface of collar 78 is spaced from inner tubular support 12 to complete the passageway extending from the ports 82 and through the space between inner tubular support 12 and outer tubular support 14 to provide a means of equalizing the pressure above and below the packing assembly P.

The collar 78 is also adapted to function as a release actuating means when it is properly manipulated. The grooves 88 in the collar '78 have a configuration to receive the pins 76 in their upwardly facing portions 84. By rotation of the tubing string T the collar 78 is rotated to position the pins 76 in the downwardly facing portions 86 of the grooves 80 for release of the packing assembly P and the anchoring assembly A, as hereinafter more fully set forth.

To actuate the setting means S by rotation of the tubing string T, the coupling has pins 88 projecting therefrom and adapted to engage in the recesses 90 defined in the upper end of collar 22. In actuating the setting means S, the springs mounted on the cage 42 hold the anchoring and packing assemblies against rotation and also allow the tubing string T and the tubular supports 12 and 14 to be lowered therethrough to position the pins 88 in the recesses 90.

In operation the well packer is lowered into a well bore as shown in FIGURE 1. When it reaches the position in the well casing C where it is to be set, the tubing string T is rotated to actuate the setting means S. If the threaded connection between the inner setting sleeve 16 and the outer setting sleeve includes right-hand threads, the tubing string T is rotated in a clockwise direction for setting. The threaded connection between

sleeves

16 and 18 is preferred to be a low-friction type connection to assure 4 that rotation of tubing string T actuates the setting means S.

The setting rotation of tubing string T causes rotation of collar 22 by the engagement of the pins 88 in the recesses 90. Since collar 22 is directly connected to inner setting sleeve 16 by the ring 20, this rotation is transmitted to sleeve 16. Outer setting sleeve 18 is held against rotation by the connection to theanchoring assembly A provided by pins'58 in the slots 62. Thus,

sleeves

16 and 18 are moved longitudinally with respect to each other to accomplish the setting of packing assembly P and anchoring assembly A.

The relative movement of the

sleeves

16 and 18 causes the upper expander 46 to be moved upward with respect to packing sleeve 28 to thereby provide an endwise setting force on the packing elements 36 causing them to expand radially into sealing engagement with the interior of the casing C. Additionally, the setting movement wedges upper expander 46 and lower expander 48 under the gripping slips 44 to move them radially into pipe-gripping engagement with the interior of the casing C. This setting operation is possible since the collar 22 which forms the upper abutment is connected to inner sleeve 16, and the lower expander 48 which forms the lower abutment is releasably engaged by the outer sleeve 18 whereby relative movement of

sleeves

16 and 18 causes setting by reducing the distance between the upper and lower abutments. The set position of the well packer is illustrated in FIGURE 2.

In the set position shown in FIGURE 2, the well packer is completely set and is not unset by exposure to high temperatures since the tubular supports 12 and 14 are slidably mounted within the packing and anchoring assemblies and the setting means. When the well packer is to be used in steam injection, the tubing string T is lifted to position the pins 76 in the portions 84 of the grooves. This position is illustrated in FIGURE 3. The ports 82 are in communication with the annular area defined by the casing C and the tubular support 14 above the packing assembly P. The passageway defined around tubular support 12 by tubular support 14 and collar 78 is in communication with the annular space below the packing assembly P. Thus, this lifting of the tubing string T provides a bypass communication around the packing assembly P which allows an equalization of pressure across the packing assembly P and allows fluids to be circulated in the annular space above the well packer; e.g., fluid flowing down through the tubing string may be returned to the surface by flowing upward in the annular area and through the bypass around the packing assembly P.

With the packing and anchoring assemblies completely set and the bypass passageway closed, pressure differentials across the packing assembly P are transmitted by the structure to assure that it remains set. For example, a pressure below the packing assembly P exerts an upward force on ring 30 which is transmitted through collar 22, ring 26,

sleeves

16 and 18 to urge lower expander 46 upward and thereby increases the force holding gripping slips 44 in pipe-gripping engagement with the casing C. A pressure above the packing assembly P exerts a down- I ward force on ring 40 to urge upper expander 46 downward and thereby increase the force holding gripping slips 44 in pipe-gripping engagement with casing C. Thus, the well packer of the present invention, when set, holds against longitudinal movement in both directions.

The release of the well packer is accomplished by the manipulation of the tubing string T and is illustrated in FIGURE 4. The tubing string is lifted to position the collar 78 as shown in FIGURE 3. In this position, the ports 82 are above the packing 32 and the pressures across the packing assembly P are equalized. Thereafter, the tubing string is rotated to position the pins 76 in the portions 86 of the grooves 80. In this position, the tubing string T is lifted to engage release ring 66 and shear the pins 68. When the pins 68 have sheared, the release ring 66 is forced upward against the projection 74 on sleeve 18. The upward force on sleeve 18, because of the tapers on shoulders 70 and 72, bends the fingers 64 inwardly to disengage the releasable connection between sleeve 18 and lower expander 48 (the lower abutment).Continued lifting of the tubing string T is transmitted through collar 78, release ring 64, sleeve 18, sleeve 16 and ring 20 to collar 22 to lift collar 22 (upper abutment) allowing packing elements 36 to return to unset position. Also, packing sleeve 28 is lifted and engages upper expander 46 to pull it out from under the gripping slips 44. Thereafter, the lifting may pull the gripping slips 44 out of engagement with lower expander 48 as suggested in the Cicero C. Brown patent application Ser. No. 299,982, filed Aug. 5, 1963. The well packer is then completely released, as shown in FIGURE 4, and may be removed from the well bore.

Because of the possibility of disconnecting the pipe joints, release which may be accomplished by a reverse rotation of the pipe string is generally not used. This form of release is accomplished by reversing the setting action of the threaded connection between

sleeves

16 and 18.

The modified form of the well packer of the present invention, illustrated in FIGURE 5, is identical to the preferred form previously discussed except for the connection of the release ring to the fingers 64 of the setting sleeve 18. For this reason, all parts have been shown to have the same numeral designations except for the modified parts.

The modified form well packer is provided to allow multiple settings and releases using the lifting release procedure previously described. In this form no shear pins connect the lower end of the fingers 64 to the release ring 92. The release ring 92 includes an outer downwardly facing shoulder 94 which engages the inner upwardly facing shoulders 96 on the fingers 64. The spring 98 surrounds the outer tubular support 14 and engages between the lower portion of projection 74 and the upper end of release ring 92. Thus, the force exerted by spring 98 on release ring 92 holds the fingers 64 of sleeve 18 in releasable engagement with lower expander 48.

The setting of the modified form of well packer proceeds exactly as the setting of the preferred form previously described with the spring 98 functioning to maintain the releasable engagement between fingers 64 on sleeve 18 and lower expander 48.

The release proceeds by the lifting release procedure wherein engagement of the release ring 92 by the collar 78 forces the release ring 92 upward with respect to the fingers 64 and compresses the spring 98. This action allows the disengagement of the fingers 64 from the lower expander 48 and complete release thereafter proceeds as previously described.

Once release of the modified form has been completed by the lifting release procedure, the well packer may be reset by rotating the tubing string T to move the fingers 64 into releasable engagement with the lower expander 48. This is possible since the springs 50 of the anchoring assembly A resist rotation and the lower expander 48 is supported by the engagement of the pins 54 in the lower end of the slots 56. With the fingers 64 repositioned, the spring 98 forces the release ring 92 downward into the position illustratedin FIGURE 5 to retain the releasable engagement between the lower expander 48 and the fingers 64 on sleeve 18.

From the foregoing, it can be seen that the well packer of the present invention may be mechanically set in a well bore by manipulation of the tubing string on which it is mounted and, when set, holds against longitudinal movement in both directions. Further, this well packer may readily be employed in applications where it is subjected to high temperatures without leaking or unsetting. By mounting the packing assembly, the anchoring assembly and the setting means around concentric tubular supports, elongation of the tubular supports from heating does not alfect the set position of the well packer; and such structure also provides a bypass communication across the packing assembly for circulation of fluids and also for equalizing pressures across the packing assembly. The well packer is provided with structure for mechanical release by lifting the tubular supports and the modified form of the well packer provides a structure which may be repeatedly set and released without removal from the well bore.

The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the 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 is claimed is:

1. A well packer adapted to be lowered and set within a well bore, comprising a tubular support,

a packing assembly surrounding said tubular support and adapted to expand radially outward when subjected to an endwise force,

an anchoring assembly surounding said tubular support and including gripping slips which are adapted to move radially outward into pipe-gripping position when moved to set position,

setting means surrounding said tubular support and operable to move said packing assembly and said anchoring assembly into set positions,

means on said tubular support for actuating said setting means responsive to rotation. of said tubular support,

said setting means having means releasably engaging one of said assemblies,

means on said tubular support adapted to release said releasable engaging means responsive to longitudinal movement of said tubular support, and means secured to said anchoring assembly and adapted to engage said release means on said tubular support in one position to prevent release of said releasable engaging means by longitudinal movement of said tubular support.

2. A well packer according to claim 1, including a second tubular support within said first-mentioned tubular support,

means connecting the upper ends of said tubular supports,

said tubular supports being slidable longitudinally through the remainder of said well packer structure,

means sealing between the exterior of said first tubular support and the interior of said packing assembly, and

a bypass passageway defined by said tubular supports,

said bypass passageway communicating from above to below said packing assembly only when said tubular supports are raised into engagement with said release preventing means.

3. A well packer adapted to be lowered and set within a well bore, comprising a tubular support,

a first abutment mounted in surrounding relation to said tubular support,

a second abutment mounted in surrounding relation to said tubular support and spaced longitudinally thereof from said first abutment,

a packing assembly surrounding said tubular support between said abutrnents and adapted to expand radially outward into sealing position with the well bore when subjected to an endwise setting force,

an anchoring assembly surrounding said tubular support between said abutments and including gripping slips which are adapted to move radially outward into pipe-gripping position when said anchoring assembly is subjected to an endwise setting force,

a first setting sleeve connected to one of said abutments and adapted to be rotated responsive to rotation of said tubular support,

a second setting sleeve threadedly engaging said first setting sleeve and releasably connected to the other of said abutments,

means restraining said second setting sleeve against rotation whereby rotation of said first setting sleeve threads said second setting sleeve and said second abutment toward said first abutment to apply an endwise settin force to said packing assembly and said anchoring assembly, and

means responsive to longitudinal movement of said tubular support to release the releasable engagement between said second setting sleeve and said other abutment whereby said assemblies may be released by rotation of said tubular support and by longitudinal movement of said tubular support.

4. A well packer according to claim 3, including means secured to said other abutment and adapted to engage said release means to prevent inadvertent release of said assemblies.

5. A well packer adapted to be lowered and set within a well bore, comprising a tubular support,

an upper abutment mounted in surrounding relation to and slidable on said tubular support,

means releasably connecting said tubular support to said upper abutment whereby rotation of said tubular support rotates said upper abutment,

a lower abutment mounted in surrounding relation to said tubular support and spaced below said upper abutment,

an upper setting sleeve connected to said upper abutment and adapted to be rotated therewith,

a lower setting sleeve threadedly engaging said upper setting sleeve and releasably engaging said lower abutment,

a packing assembly surrounding said tubular support between said abutments and adapted to expand radially outward into sealing position with said well bore when subjected to an endwise setting force,

an anchoring assembly surrounding said tubular support between said abutments and including gripping slips which are adapted to move radially outward into pipe-gripping position when said anchoring assembly is subjected to an endwise setting force.

means restraining said lower setting sleeve against rotation whereby rotation of said upper setting sleeve threads said lower setting sleeve thereon to move one of said abutments toward the other of said abutments to apply an endwise setting force to said packing assembly and said anchoring assembly, and

means on said tubular support adapted to release the releasable engagement between said lower setting sleeve and said lower abutment.

6. A well packer according to claim 5, including means secured to said lower abutment and adapted to engage said release means on said tubular support to prevent inadvertent release of said assemblies.

7. A well packer according to claim 6, wherein said lower setting sleeve includes a plurality of flexible fingers adapted to engage said lower abutment, and

a release ring surrounding said tubular support and holding said flexible fingers in engagement with said lower abutment,

said release ring adapted to be moved out of holding engagement with said fingers by said release means on said tubular support.

8. A well packer according to claim 7, including a shear pin connecting said release ring to one of said flexible fingers.

9. A well packer according to claim 7, including a spring surrounding said tubular support and urging said release ring in a direction to maintain holding engagement with said fingers.

10. A well packer according to claim 7, wherein said release means on said tubular support is a grooved collar and said release preventing means includes a sleeve with pins adapted to slide in the grooves in said grooved collar.

11. A well packer according to claim 10, wherein the grooves in said grooved collar engage said pins in one position to prevent further upward movement of said grooved collar and in another position disengage from said pins to move upwardly into engagement with said release ring moving said release ring out of holding engagement with said flexible fingers for release of said assemblies.

12. A well packer adapted to be lowered on a tubing string and set within a well bore, comprising an inner tubular support,

an outer tubular support surrounding and spaced radially from said inner tubular support,

means connecting said inner and outer tubular supports to the tubing string on which the well packer is to be supported,

a collar surrounding and slidable with respect to said outer tubular support,

means sealing between said collar and said other tubular support,

means providing rotating engagement between said collar and said tubing string,

a first setting sleeve in surrounding relation to said outer tubular support and secured to said collar and adapted to be rotated thereby,

a packing assembly surrounding said tubular supports and retained against longitudinal movement with respect to said collar,

said packing assembly adapted to expand radially outward into sealing position with the well bore when subjected to an endwise setting force,

an anchoring assembly surrounding said tubular supports and connected to said packing assembly,

said anchoring assembly including gripping slips which are adapted to move radially outward into pipegrippin position when said anchoring assembly is subjected to an endwise setting force,

a second setting sleeve threadedly engaging said first sleeve,

means on said second setting sleeve releasably engaging said anchoring assembly,

means preventing rotation of said second setting sleeve and said anchoring assembly,

means adapted to release said releasable engaging means whereby said second setting sleeve is disengaged from said anchoring assembly for release of said packing and anchoring assemblies from set position,

rotation of said tubing string in one direction rotating said inner setting sleeve with respect to said outer setting sleeve to thread said sleeves together longitudinally whereby the distance between said collar and said anchoring assembly is reduced to exert an endwise setting force on said packing assembly and said anchoring assembly setting said packing assembly and moving said gripping slips into pipe-gripping position,

rotation of said tubing string in the other direction rotating said inner setting sleeve with respect to said outer setting sleeve to thread said sleeves apart longitudinally and thereby relieve said endwise setting force on said packing assembly and said anchoring assembly to unset said assemblies, and

means on the lower end of said outer tubular support adapted to engage and release said releasable engagement between said second setting sleeve and said anchoring assembly whereby said packing and anchoring assemblies may be released from set p0si- References Cited tion by lifting said tubing string. 1 P 13. A well packer according to claim 12, including UN TED STATES ATENTS means supported on said anchoring assembly to engage 2149879 1 2/1950 Clark 166-139 said release means on said outer tubular support to 5 3,075,584 1/1963 BFOWH l66-134 prevent inadvertent release of said releasable engage- 312891766 12/1966 Blgelow 166-139 ment between said second setting sleeve and said anchoring assembly- JAMES A. LEPPINK, Prmmry Exammer.

Claims

1. A WELL PACKER ADAPTED TO BE LOWERED AND SET WITHIN A WELL BORE, COMPRISING A TUBULAR SUPPORT, A PACKING ASSEMBLY SURROUNDING SAID TUBULAR SUPPORT AND ADAPTED TO EXPAND RADIALLY OUTWARDLY WHEN SUBJECTED TO AN ENDWISE FORCE, AN ANCHORING ASSEMBLY SURROUNDNG SAID TUBULAR SUPPORT AND INCLUDING GRIPPING SLIPS WHICH ARE ADAPTED TO MOVE RADIALLY OUTWARD INTO PIPE-GRIPPING POSITION WHEN MOVED TO SET PORTION, SETTING MEANS SURROUNDING SAID TUBULAR SUPPORT AND OPERABLE TO MOVE SAID PACKING ASSEMBLY AND SAID ANCHORING ASSEMBLY INTO SET POSITIONS, MEANS ON SAID TUBULAR SUPPORT FOR ACTUATING SAID SETTING MEANS RESPONSIVE TO ROTATION OF SAID TUBULAR SUPPORT, SAID SETTING MEANS HAVING MEANS RELEASABLY ENGAGING ONE OF SAID ASSEMBLIES, MEANS ON SAID TUBULAR SUPPORT ADAPTED TO RELEASE SAID RELEASABLE ENGAGING MEANS RESPONSIVE TO LONGITUDINAL MOVEMENT OF SAID TUBULAR SUPPORT, AND MEANS SECURED TO SAID ANCHORING ASSEMBLY AND ADAPTED TO ENGAGE SAID RELEASE MEANS ON SAID TUBULAR SUPPORT IN ONE POSITION TO PREVENT RELEASE OF SAID RELEASABLE ENGAGING MEANS BY LONGITUDINAL MOVEMENT OF SAID TUBULAR SUPPORT.