US3011558A - Well conduit anchoring apparatus - Google Patents

Description

Dec. 5, 1961 M. B. CONRAD 3,011,558

WELL CONDUIT ANCHORING APPARATUS Filed Dec. 24, 1957 4 Sheets-Sheet 2 li a. 4'. li a 6.

Jrraemzrs.

Dec. 5, 1961 M. B. CONRAD WELL CONDUIT ANCHORING APPARATUS 4 Sheets-Sheet 3 Filed Dec. 24, 1957 IN VENTOR. Men/v 48 Cam/e40 Dec. 5, 1961 M. B. CONRAD WELL CONDUIT ANCHORING APPARATUS Filed Dec. 24, 1957 IN VENTOR. MJPT/A/Ba 6" 0/1/240 3,611,558 WELL CGNDUIT ANCHORING APPARATU Martin B. Conrad, Downey, Califi, assignor to Baker Oil Tools, lne llos Angeles, Calif, a corporation of (Talifornia Filed Dec. 2.4, 1957, Ser. Nix-704,925

' l9 (Ilaims. (Cl. 166-212} The present invention relates to subsurface well bore apparatus, and more particularly to apparatus to'be anchored in well conduits, such as well casing and liners.

An object of the present invention is to provide anchoring apparatus to secure a running-in string, such as a tubular string, in a Well conduit, which is relatively simple in construction, compact, and economical to manufacture, and which is still capable of safely withstanding comparatively high pressure differentials in the well conduit.

Another object of the invention is to provide subsurface anchoring apparatus to secure a running-in string in a well conduit, which is capable of remaining anchored against the force of hydraulic pressure tending to shift it in a particular longitudinal direction, and .which can be released from anchored condition by movement of the running-in string in such particular longitudinal direction. By wayof. example, if the anchor withstands hydraulic pressure tending to shift it upwardly in the well conduit, the anchor can be released by taking an upward pull or strain on the running-in string.

A further objectof the invention is to provide subsurface anchoring apparatus whichis capable of remaining anchored in the well conduit against high pressure diiferentials, and which can be released from the Well conduit by the taking of a strain on the running-in string of relatively low magnitude.

An additional object of the invention is to provide subsurface anchoring apparatus in which a-' relatively large force is necessary to shift parts of theapparatus from retracted to expanded positions, the forcenecessary to retract the parts from their expanded position being relatively small. Inadvertent setting of the'anchor in a well conduit is, therefore, avoided.

Yet another object of the invention is to provide improved anchoring apparatus to be set in a wellconduit and retained in a set condition by fluid pressure in- -ter'nally of the apparatus.

Still a further object of the invention is to provide anchoring apparatus to be set in a well conduit and retained in suchcondition by fluid pressure differential externally of the apparatus.

This invention possesses many other advantages, and

'has other objects which may be made more clearly apparent from a consideration of several forms in which it may be embodied. Such forms are shown in the drawings accompanying and forming part of the present specification. These forms will now be described in detail, for the purpose of illustrating the general principles of the invention; but it is to ,be understood that such detailed description is not to ,-be taken in a limiting sense,

since the scope of the invention is best defined by the appended claims.

Referring to thedrawings: v

FIGURE 1 is a longitudinal section through an anchoring apparatus disposed in a well casing, with parts of the anchoring apparatus in retracted position;

FIG. 2 is a cross-section taken along the line 2-2 on FIG. 1;

FIG. 3 is a cross-section taken along the line 3 -3 on FIG. 1;

FIG. 4- is a quarter longitudinal section similar to FIG.

3,011,558 Patented Dec. 5, 1561 2 1, illustrating the apparatus anchored in the well casing against upward movement therewithin;

FIG. 5 is an enlarged viewjof a portion of the apparatus shown in FIG. 4; I

FIG. 6 is a quarter longitudinal section through another embodiment of the apparatus,'with the parts in retracted position;

FIG. 7 is a view similar to, FIG. 6 of the anchoring apparatus set in anchored condition against the well casing;

FIG. 8 is a View similar to FIG. 6 of still another embodiment of the invention, with the parts in retracted position;

FIG. 9 is a view similar to FIG. 8 illustrating the anchoring apparatus anchored in the well casing;

FIG. 10 is a side elevation, on an enlarged scale, of the latching or-coupling sleeve portion of the apparatus illustrated in FIGS. 1 to 5, inclusive;

FIG. 11 is an enlarged fragmentary section through a portion of the apparatus illustrated in FIGS. 6' and 7;

FIG. 12 is a full cross-section, on an enlarged scale, taken along the line 12- 12 on FIG. 6;

FlG. l'3is a full cross-section, on an enlarged scale, taken along the line 13-13 on FIG. 6;

FIG. 14 is a cross-section taken along the line 14-14" on FIG.-9.

in the form of invention illustrated in FIGS. 1 to 5, inclusive, and- FIG. 10, an anchor A is secured to a running-in string B, such as a tubularstring extending to the top of the well bore, and is lowered in a well casing C to a desired point therein at which it is to be secured .to a body coupling 12 which is, in turn, threadedly se cured to the lower portion of an adjacent section of tubing constituting part of the tubing string B extending to the top of the well bore. Similarly, the lower end of the body may be constituted as a threaded pin 13 threadedly attached to a coupling 14 which is, in turn,

threadedly secured to the body portion of the lower tool D, such as a set down type of well packer.

The anchor is to besecured to the well casing C against longitudinal movement therewithin in one direction, such as in an upward direction. To accomplish this purpose, a plurality .of circumferentially spaced slips 15 are disposed around the body 10 of the tool, the slips being capable of being shifted between retracted and expanded positions, and of partaking of joint longitudinal movement. Thus, the upper portion of each slip is slidable in a slot 16 extending through the lower portion of a slip retainer ring 17 slidable on the body or mandrel 10, the slip having oppositely directed tongues vl8 adapted to be received within companion grooves 19 in the sidesof the slot. Preferably, the tongues and grooves 18, 19 are inclined to a small extent in an upward and outward direction, to facilitate anchoring of the slips 15 against the well casing B, and their retraction therefrom. The lower portions of the slipshave external wickers or teeth 20 which face in an upward direction to engage andem-b'ed themselves in the wall of the well casing.

The inner surfaces 21 of the slips are tapered in an upward and inward direction, coacting with companion tapered surfaces 22 on an expander 23 slidably mounted on the body or mandrel 10 of the tool. The slips 15 and expander 23 are slidably splined to one another, such that their relative longitudinal movement in one direction will effect expansion of the slips 15 into anchoring engagement with the well casing, whereas relative longitudinal movement in the opposite direction will effect positive retraction of the slips from the well casing. Such connection is afforded by means of oppositely directed tongues 24 on the inner portion of each slip slidable in companion grooves 25 in the expander. It is evident that the tongues 24 and the grooves 25 are inclined in an upward and inward direction to the same extent as the coengaging expander surfaces 21, 22.

The slip ring 17 is movable upwardly on the body 10 of the tool to the extent limited by its engagement with the lower end of the body coupling 12. Its downward movement relative to the body is determined by its. engagement with an upwardly facing body shoulder 27. The slip ring 17 and, consequently, the slips 15, on the one hand, and the expander 23, on the other hand, are normally urged in directions away from each other to tend to retain and place the slips in their retracted positions by spring means 28 acting between the slip retainer ring 17 and the expander 23. As disclosed, longitudinally extending, circumferentially spaced helical compression springs 28 are arranged between the slips 15, the upper ends of the springs being disposed Within sockets 29 in the slip retainer ring and bearing against the upper portions of the socket. The springs 28 are tclescoped over longitudinal centering pins 30 fitting within bores 30' in the expander, with the lower ends of the springs bearing against the upper end of the expander. It is evident that the springs 28 tend to shift the slip retainer ring 17 and slips 15 in an upward direction relative to the expander 23, such that the inclined tongue and groove connection 24, 25 between the slips and expander tend to hold and return the slips in a retracted position. However, when the expander 23 is shifted upwardly relative to the slips, the latter are urged in a radial outward direction to place their wickers 2% in anchoring engagement with the wall of the well casing C. I

Depending from the expander 23 is a cylinder sleeve portion 31 of a hydraulic cylinder 32, which is spaced from the mandrel 19 of the tool to provide an annular cylinder space 33 therebetween in which a hydraulicallyactuatable latch or coupling sleeve member 34 is disposed. Actually, the lower portion 23a of the expander may be considered to constitute an annular cylinder head, which is disclosed as being integral with the depending cylinder skirt 31, although it is evident that, if desired, the head and skirt may be made separate from one another and suitably secured together, as by welding or threading.

The latch or coupling sleeve 34 includes an intermediate annular piston portion 35 which is slidable along the periphery of the body it), and also along the lower inner wall portion 36 of the cylinder. The piston portion 35 is always disposed below one or a plurality of fluid inlet ports 37 establishing communication between the central passage 33 through the body and the annular cylinder space 33 between the body 10 and the cylinder 32 above the piston. Leakage of fluid in an upward direction from the cylinder space 33 is prevented by a suitable side seal, such as a rubber or rubber-like O ring 39, disposed in an internal groove 4ft in the cylinder head 2311 or expander and slidably sealing against the periphery of the body. Leakage of fluid in a downward direction from the annular cylinder space 33 is prevented by an inner side seal ring 4-1, such as a rubber or rubber-like ring, disposed within an internal groove 42 in the piston and slidably sealing against the periphery of the body below its ports 37. Leakage of fluid between the periphery of the piston 35 and the adjacent cylinder wall 36 is prevented by a suitable side seal ring 43, such as a rubber or rubber-like 0 ring, disposed in a ring groove 44 in the piston and slidably sealing against the cylinder wall.

When fluid under pressure differential enters the cylinder space 33 from the interior of the body and through the ports 37, such pressure tends to shift the cylinder 32 and expander 23 in an upward direction, at first shifting the slip retainer ring 17 into engagement with the lower end of the coupling 12, which functions as a stop, the expander 23 then moving upwardly along and behind the slips 15 to expand them radially into anchoring engagement with the wall of the well casing C. However, it is desired that a substantial pressure differential be required before the expander can move upwardly to effect outward expansion of the slips. Accordingly, relative movement between the expander 23 and the body it? of the tool is at first precluded by a releasable retainer device 45 acting between the coupling sleeve 34- and the cylinder skirt 31.

in addition, it is desired that the body or mandrel 10 be directly coupled to the expander 23 after the slips 15 havebeen expanded into anchoring engagement with the wall of the well casing C, such that hydraulic forces acting on the body from below the anchor A will be transmitted directly from the body 10 to the expander 23, and through the slips 15 to the wall of the well casing.

Both the aforenoted releasable retainer feature and di-' rect transmission of upward thrust are accomplished in the present instance by forming the lower portion of the latch or coupling sleeve 34 with depending spring-like feet 46, which are produced by cutting a plurality of circumferentially spaced slots 47 through the lower portion of the sleeve or member 34 to the region of the intermediate annular piston 35. These spring-like legs (i6 terminate in,

outwardiy directed foot portions 48 which are initially located in an internal circumferential groove 49 in the lower portion of the cylinder sleeve 31. The lower outer end 51; of these feet are tapered in an inward and downward direction, engaging a companion tapered surface 51 defining the lower end of the internal groove 49. Any

tendency for the cylinder 32 to shift upwardly with respect to thesleeve 34 causes the inclined cam surfaces 59, 5 1 to coengage and tend to shift the feet 43 inwardly out of the groove 49. The spring-like legs 46 and feet 48 resist such inwardly directed forces. However, when the forces are suflicient, the spring legs 46 will be deflected inwardly to the extent in which the foot portions 43 are removed from the groove 49.

The force to effect such inward shifting of the spring legs 46 and feet 455 is provided by the pressure differential within the annular cylinder space 33, which acts downwardly upon the annular piston 35. Such downward movement is not only resisted by the necessity to shift the spring feet 48 out of the groove 49, but also by virtue of upwardly extending arms 52 forming the upper portion of the latch or coupling sleeve 34, which are produced by longitudinal slots 53 opening through the upper end of the sleeve and extending downwardly to the region of the annular piston 35. These arms 52 terminate in inwardly directed thrust heads or elements 54 having inner, lower carn surfaces 55 tapering in an upward and inward direction and coacting with companion tapered surfaces 56 on an expander and lock portion 57 integral with the body lil. After the latch or coupling sleeve 34 has shifted downwardly, or, conversely, the cylinder 34 and expander 23 have been shifted upwardly hydraulically, for the purpose of removing the feet 48 from the groove 49, (which will then allow the expander 23 to move upwardly behind the slips 15 to expand the latter into anchoring engagement with the well casing), the pressure within the cylinder is acting on the piston '35, urging the coupling sleeve 34 downwardly, the coengaging thrust head and expander surfaces 55, 56 overcoming the elasticity or resiliency of the spring arms 52 and shifting them laterally outward to the extent determined by engagement of longitudinally extending teeth 58 on the arms with companion teeth 59 formed in the inner wall of the upper portion of the cylinder sleeve 31. When such teeth 58, 59 coengage as a result of outward expansion of the spring-like arms 52 and thrust heads 54, the expander surfaces 55, 56 are still engaged, and the body 163 and cylinder sleeve 31, as well as the expander 23 integral with and secured to thelatter, are directly coupled to one another, any upwardly directed forces on the body 10 being transmitted through the body expander 57 and thrust heads 54 to the cylinder sleeve 31 and expander 2-3, the expander. being wedged behind the slips 15 to transmit such forces through the latter to the well casing or corresponding well conduit C.

When the pressure differential within the cylinder '32 is relieved, the hydraulic force acting downwardly on the annular piston 35 is also relieved, which permits the arms 52 and the thrust heads 54 to inherently return to their retracted positions, such as disclosed in FIG. 1.

As described above, the latch sleeve 34 can only'rnove to a limited extent downwardly with respect to the body 10, as determined by outward expansion of the arms 52 and the engagement of their teeth 58 with the companion teeth 59 in the cylinder Wall. Upward movement of the latch or coupling sleeve 34 along the body 10 is also limited, to retain the heads 54 in position for engagement with the expander and lock surface 56 on the body It), by an external flange 6% on the body disposed immediately above the heads 54. Similarly, downward movement of the expander 23 along the body It? and the latch or coupling sleeve 34 is limited by engagement of a downwardly facing cylinder shoulder 61 with the upper end of the annular piston 35. The full retraction of the slips 15 against the body or mandrel 10 of the tool will also limit the downward movement of the expander 23 and cylinder 32 along the body 10, by virtue of the inclined tongue and groove interconnection 24, 25 between the slips 15 and the expander 23.

For the purpose of facilitating assembly of the coupling sleeve 34 on the body 10 with its thrust heads 54 disposed between the expander and lock surface 56 and the fian e 69 thereabove, the expander and lock portion 57 is provided with slots 62 having a circumferential or arcuate extent corresponding to the circumferential extent of each arm 52 and head 54. tween the body slots 62 are the circumfcrentially spaced expander and lock portions 5'7, which correspond in arcuate extent with the slots or spaces 53 between the arms 52. r

his to be noted that the interrupted expander and lock portion 57 of the body has a substantially larger external diameter than the body portion therebelow. In assembling the latch or coupling sleeve 34 on the body,

, the latter is inserted over the lower portion of the body it with the arms 52 and thrust heads 54 aligned with the slots 62 between the expander and lock portions 57. The thrust heads 54 are then inserted through the slots 62 until the thrust heads 54 are disposed between the expander surface 56 and the flange 6i? thereabove, whereupon the coupling sleeve 34 is turned with respect to the body 10 to place the thrust heads in alignment with the expander and lock elements 57, the heads 54 then being disposed above these latter elements. The latch or coupling sleeve 34 is retained properly aligned or oriented with respect to the expander and lock elements 57 by means of an orienting screw 63 threaded into the body 10 between a pair of adjacent thrust head portions 54. This screw 63 will prevent substantial angular shifting of the thrust sleeve 34 on the body and will insure the proper engagement between the thrust head surfaces 55 and the expander and lock surfaces 56.

In one manner of using the anchoring apparatus, the lower portion of its body llt) may be secured to the lower tool D, such as a set down packer, and its upper portion to the tubular string B, by means of which the entire apapratus is lowered in the well casing C, or similar conduit, to the location at which the apparatus is to be used. During such lowering action, the parts occupy the relative positions illustrated in FIG. 1, in which the helical springs 28 tend to hold the slips and expander 23 in their relative separated condition,

the slips being retracted and the feet 48 of the releasable retainer portion of thev coupling sleeve 34 disposed in the internal groove 49, so as to prevent upward movement of the expander23 relative to theslips 15. At this time,'the thrust heads .54 are disposed in their retracted position with respect to the cylinder 32 and lock portions 57 of the mandrel or body 10 of the tool.

After the apparatus has reached the location at which the anchor A is to be set against the well casing C, the

lower tool D may be set therewithin, as by suitably manip- H ulating the tubular string B, such motion being transmitted through the body 1010 the lower tool. lower too-l includes slips, an expander and a packing structure, the slips being expanded against the well casing by imposing a downwardly directed weight on the tubular string B. After the slips are expanded, the packing structure of the lower tool (not shown) is sealed off against the wall of the well casing. Fluid under pressure may now be pumped through the tubular string B, passing through the body 10 of the tool A and through the lowertool D. For example, a formation fracturing operation may be performed. Such fluid under pressure will act through theports 3'7 and be imposed on the fluid in the annular cylinder 33-, urging the coupling sleeve 34 in a downward direction and the cylinder 32 and expander 23 connected therewith in an upwarddirection. However, movement of the piston 35 in a downward direction is precluded by the spring action of the arms 52 and the thrust heads 54 engaging the expander and lock portion 57 of body or mandrel it whereas,

movement of the expander and cylinder in an upward direction is resisted by engagement of the lower tapered side 51 of the groove 49 with the companion tapered ends 59 of the releasable retainer sleeve 34. vWhen the pressure differential in the cylinder 32 exceeds the resisting force of the spring legs 46 and their feet 48, the latter are carrnned inwardly, which then permits the fluid pres,

sure to shift the cylinder 32 and expander 23 upwardly, such action carrying the slips '15 and slip retainer ring 17 upwardly until the slip retainer ring engages the stop coupling 12. The expander 23 then moves toward the clip retainer ring 17 against the force of the springs 23, compressing the latter and moving up along the slips 15 to expand them laterally outward, until they are en aged with the well casing C. 'As the pressure increases, the expander 23 is wedged more firmly behind the slips '15, to hold them anchored against the wall of the well casing.

During such increase in pressure, the piston 35 is moving downwardly relative to the body 1% and the cylinder 32, the thrust heads 54 shifting down along the expander and lock surfaces 56 and laterally outwardly until the teeth 58 .on the arms 52 are meshed with the internal teeth 59 in the cylinder sleeve 31 (FIG. 4). within the cylinder 32 is constantly urging the piston 35 and the complete coupling sleeve 34 in a downward direction, to hold the arms 52. in full mesh with theteeth 58 of the sleeve 31. Such pressure is .also acting in an upward direction on the cylinder head 23a and expander 23, to hold the latter wedged behind the slips 15. The same pressure is actingin an upward direction over the lower tool 1), such as a set down type of packer, and is tending to shift it in an upward direction. Such upward shifting force is transmitted through the body it) of the tool A to the expander and lock members 57, and through the latter to the thrust heads 54, which are meshed with the teeth 5? on the cylinder sleeve 31, the force being transmitted through the cylinder sleeve and expander 23 to the slips l5, and thence to the casing C. Accordingly, there is a direct transmission of the hydraulic forces below the tool A, and tending to shift the body 10 of the tool in an upward direction, through the expander 23 and slips 15 to the casing C, preventing upward movement of the apparatus, the equipment being anchored against such upward movern'ent.-

Usually such The pressure In the event the anchoring apparatus A is to be released from the well casing, the internal pressure in the apparatus, as well as the pressure below the lower tool D, is relieved. When the pressure differential within the tool drops below a force equivalent to that of the helical springs 28, the latter can shift the expander 23 and cylinder 32 downwardly relative to the slips l and the body 19 of the tool, the teeth 59 on the cylinder bearing against the teeth 5'8 on the arms 52 and thrust heads 54 and camrning the latter inwardly, so that the cylinder 32 can,

in effect, ratchet downwardly along the coupling sleeve 34 until the lower tapered end 65 of the cylinder, which diverges in a downward direction, engages companion tapered surfaces lid on the upper portions of the feet 48, to cam the spring legs 45 inwardly until the feet are opposite the internal groove 45), whereupon the legs and feet can inherently spring outwardly to their initial condition, in which the feet 43 are again located in the groove 49 to releasably retain or lock the cylinder 32 and expander 23 with respect to the body or mandrel ill? of the tool (FIG. 1). The apparatus A can now be moved longitudinally in the well casing C and may, if desired, he removed completely therefrom.

If, for some reason, such as the presence of foreign material in the cylinder 32 or other portions of the apparatus, the springs 28 are incapable of returning the anchoring apparatus to a retracted condition, such condition can be achieved in a mechanical fashion. in the form of device illustrated in FIGS. 1 to 5, inclusive, and the taking of an upward pull on the tubular string B and the body ltl of the tool will result in a retraction of the slips l5 from the well casing, despite the fact that the slips normally anchor the tool in the well casing against upward movement therewithin.

The angle R that the tapered surfaces 55, 2'56 on the expander 57 and thrust heads 54 makes to the axis of the apparatus is substantially greater than the angle S that the surfaces of the coengaging teeth 52 makes to the axis of the apparatus (PEG. 5, particularly). By way of example, the surfaces 55, 5'6 on the expander 57 and the thrust heads '5 may make an angle R of about 30 degrees to the vertical, whereas the tooth surfaces may make an angle S of about degrees to the vertical. With this relative angular relationship, the engaging surfaces of the teeth may be considered to be retractor surfaces, since they can effect retraction of the thrust heads 54, as described hereinbelow. Accordingly, following relieving of the pressure diiferential in the apparatus, and with the slips 15 in anchored position against the well casing, such as disclosed in FIG. 4, an upward strain may be taken on the tubular string B and the body r mandrel iii of the tool. Such upward pull is transmitted through the expander 57 to the thrust heads 54, and from the latter through the coengaging teeth 5d, 59 to the cylinder 32 and expander 23, the force passing from the expander 23, through the slips 15 to the well casing C. inasmuch as the angle of inclination S of the tooth surfaces to axis of the tool is substantially less than the angle R of the expander and thrust head surfaces to the axis of the tool, a much greater lateral force component is being exerted between the cylinder teeth 59 and arm and thrust head teeth 58, tending to shift the arms 52 and thrust heads 54 inwardly, than is being exerted between the expander E7 and thrust heads 54, tending to shift the thrust heads 54 and arms 52 outwardly. The result of the relative angular relationship between the parts is that the taking of a sufficient upward pull on the tubular string B and the body 19' will cause the coengaging teeth 58, 59 to pinch, retract or cam the arms 52 and thrust heads 54 inwardly out of engagement with the cylinder teeth 5?, so that the body 10 of the tool and the arms 52 and heads 54- can then move upwardly relative to the expander 23, slips 15 and slip ring 17. Such upward movement will occur until the body shoulder 27 engages the slip retainer ring 17, after which a continuation of the upward pull will cause the body to move the slip retainer ring 17 and the slips 15 coupled thereto upwardly relative to the expander 23, effecting a retraction of the slips 1% with respect to the expander 23, in view of the inclined slidable tongue and groove connection 24,. 25 therebetween. Actually, it may only be necessary for the shoulder 27 to engage the slip retainer ring 17 and move the slips 15 a slight distance to disengage them from the well casing, after which the springs 23 become effective to shift the expander 23 downwardly relative to the slips 15 and the body 16 of the tool back to its initial position, such as disclosed in FIG. 1, in which the parts of the tool are again releasably retained in their retracted conditions.

Although the anchoring apparatus has been described in connection with the use of the lower tool D, it can be used alone to anchor the tubular string C in the Well casing. The tubular string can be maintained in tension, provided a sufiicient pressure differential is within the tool, such that the imposition of a relatively high tensile strain will not cause the teeth 58, 59 to force the arms 52 and heads 54 in an inward direction to release the body in of the tool from direct coupling with the expander 23.

In the form of invention illustrated in FIGS. 6, 7, 12 and 13, an anchoring apparatus E is disclosed which is capable of functioning in essentially the same manner as in'the embodiment previously described and of accomplishing the same purposes. The slip retainer ring 17, slips 15, and expander 23 arrangement is essentially the same as illustrated in FIGS. 1 to 5, inclusive, except that the springs 28 are not provided between the slip retainer ring and the expander. Instead, the spring force is exerted between the cylinder sleeve portion 31a of the cylinder 32a, which is threadedly secured to the cylinder head 23b, or lower portion of the expander, and the body 10a of the tool. Moreover, a diiferent releasable retainer device is illustrated for precluding inadvertent shifting of the anchoring apparatus to a set position against the well casing.

As shown in the drawings, they lower portion of the cylinder skirt 31a has an inwardly directed flange or read 7% adapted to engage the lower end of a split, contractile ring or retainer 71, which may have circumferentially spaced, longitudinally extending grooves 72 in its periphery, to increase the flexibility of the ring.- This ring 71 fits partly within a circumferential groove 73, in the body or mandrel ltla of the tool, its outer portion engaging the flange 76, as above described. The upper side 74 of the groove 73 is tapered in an upward and outward direction, engaging a companion tapered surface 75 on the upper inner corner of the ring 71 (FIG. 11). The upper outer corner '76 of'the ring is tapered in an upward and inward direction, engaging a companion tapered surface 77 on a spring seat 'or ring 73, against which the lower end of a helical compression spring 79 bears, the upper end of this spring bearing against a body spring seat 80, consisting of a solid ring 81 engaged by the spring fitting Within an external recess 82 in a twopicce ring 83 mounted within a circumferential groove 24 in the body. The solid ring 82 will hold the twopiece ring 83 in the groove 84, the spring force being transmitted through the solid ring 82 and the two-piece ring to the body or mandrel 10a of the tool E.

An expander and lock element 57a is disposed on the exterior of the body 10a and rests upon the two-piece ring 83. This expander and lock has an expander surface Sa tapering in an upward and inward direction, engaging companion tapered surfaces 55a on thrust heads 54a formed at the lower portions of arms 52a integral with an annular piston 35a slidable in the cylinder space 33a formed between the cylinder skirt 31a and the body lila of the tool. The arms 52a and thrust heads 54a are defined between circumferentially spaced longitudinally extending slots extending from the lower end. of the latch or coupling sleeve 34a to the annular piston portion 35a an inward position. 58a thereon adapted to engage companion internal teeth inthe cylinder skirt'ila initially positioned therebelow. i v} As in the other form of the invention leakage of fluid from the cylinder space 33:: is prevented by a suitable side seal ring 39a mounted in the cylinder head 23b and a engaging the periphery of the body 10a above the body inlet ports 37a. A side seal ring 41a is mounted in the piston 35a and engages the periphery of the tool body ltla below the inlet ports 37a, while another side seal ring 43a is mounted on the piston and engages the cylinder wall 36a. An additional seal 96 may also be provided to insure against leakage through the threaded connection 91 between the cylinder head 23b and the cylinder sleeve 31a.

In the use of the apparatus illustrated in FIGS. 6, 7, 12 and 13, the parts initially occupy the position shown in FIG. 6, in which the split retainer ring 71 is fitting within the body groove 73 and provides a spring force, in addition to that furnished by the helical spring 79, resisting upward movement of the cylinder 32a and expander 23 along the body like and slips 15. After the apparatus has been run in the well casing to the desired point of use therewithin, the increase of the fluid pressure in the body 100 of the tool, ports 37a, and the cylinder space 33a to a suflicient extent will exert an upward force on the cylinder 32a and a downward force on the piston 35a, sliding the latch and coupling sleeve 54:: downwardly, but with its teeth 58a engaging the smooth periphery of the cylinder wall 36a above the cylinder teeth 5%. The upward force on the cylinder 32a is transmitted through its flange 7t) to the'split retainer ring 71, and from the inclined upper surface 75 of the latter to the body 10a of the tool.

When the fluid pressure becomes sufficiently high, the spring force of the split ring 71 tending to hold it in retracted position is overcome, the inclined surfaces 74, 75 expanding the ring and camming it out of the groove 73, whereupon the expander 43 and cylinder 32a can move upwardly, being resisted only by the force of the helical compression spring 79, which is much less than the force required to expand the split contractible ring 71 out of the groove 73. The cylinder 32a, expander 23, slips i5, and slip retainer 17 move upwardly until the retainer ring 17 engages the body coupling 12, after which the expander moves upwardly relative to the slips to expand them radially into anchoring engagement with the wall of the well casing C. During such upward movement of the expander 23 and its cylinder 32a, the split contractible ring 71 merely slides along the periphery of the body We above the groove, 73, exerting very little resisting force to upward movementof the parts in expanding the slips 15 into anchoring engagement with the well casing. During the movement of the cylinder 32a in a slip expanding direction, its teeth 59a will ratchet over the companion teeth 58a. on the thrust heads 54a, andwhen the slips 15 have been anchored against the well casing, the cylinder teeth 59a and the thrust head teeth 58a will be coengaged, the expander and lock 57a on the body engaging the thrust heads 54:: to maintain such engagement.

As the pressure continues to increase, it urges thecylinder 32a and expander Z3 upwardly, to holdthe slips15 more firmly anchored against the well casing. At the same time, the fluid pressure is actingdownwardly on the coupling sleeve 34a to hold it solidly wedged be tween the expander and lock 57a on the body and the cylinder 32a. Any tendency for the body 10a to move upwardly is resisted, since such upward force is transferred through the two-piece ring 83, expander 57a and thrust heads 54a to the cylinder sleeve 31a and expander 23, there being a direct mechanical connection therebee to tween wedging the expander 23 more firmly behind the slips 15 (FIG. 7). in the event the anchoring apparatus is to be released from the well casing, the pressure differential need merely be relieved, which will allow the spring 79 to expand and urge the cylinder 32a and expander 23 in a down ward direction relative to the body 1011. Such, downward movement can take place without any substantial resistance offered by the split contractile ring 71, other than its sliding friction along the periphery of the body, until the expander 23 and cylinder 32a have been moved downwardly to substantially their full extent, in which the split contractile ring 71 will snap back into the companion body groove 73. At this time, the slips 15 will then have fully retracted from the well casing C, permitting the apparatus to be Withdrawn therefrom, if desired. In the event the parts do not move to their retracted position, then the taking of an upward pull on the tubular string C and body 19a of the tool will cause the arms 52a and thrust heads 54a to be pinched inwardly by the coengaging cylinder threads 5911 and thrust head threads 58a, the body 10a moving upwardly until the shoulder 27 differential being imposed within the tool to overcome the spring force of the contractile ring 71 and the force of the helical spring 79. Such combined spring forces are far greater than that oitered by the'helical spring 79 itself. Accordingly, the helical spring can shift the anchoring apparatus to a retracted position against relatively light resistance, whereas the hydraulic pressure can only effect a shifting of the slips 15 to an anchored position against a comparatively great resistance, thereby preciudin relatively small pressure ditferentials from effecting a setting of the tool in the well casing.

The anchoringapparatus illustrated in FIGS. 8 and 9 is specifically designed to prevent downward movement of the apparatus F relative to the well casing C, rather than its upward movement. In addition, it is anchored against the well casing in response to pressure differential-s in the annulus H between the tubular string and the well casing, rather than as a result of a pressure differential internally of the apparatus. It will also resist downward movement of the tubular string and body of the tool within the well casing. i I

As disclosed, the lower slip retainer ring 17a is slidably mounted on the tubular body 1% of the tool, there being lower slips 15a slidably coupled to this retainer ring 1701 and having their wickers or teeth 2dr: facing in .a downward direction, so as to be anchored. to the well casing against downward movement therewithin. The slips 15a are slidabiy coupled to an expander 23d, the companion tapered surfaces 21, 22 between these parts being inclined in a downward and inward direction. The

expander 23d is threadedly secured to the sleeve 31b of a cylinder 32b. The upper portion 23a of. the expander may be considered to be a lower cylinder head. -,The cylinder sleeve 31b extendsupwardly along the body and terminates in an inwardly directed flange 7% slidable on being located on the body below the body side ports 37b,

its downward; movement being limited by engagement with a body flange 162. This piston 35b forms part of a latch or coupling sleeve 34b, which is similar to that disclosed in FIG. 6, except that the sleeve is inverted. It includes the circumferentially spaced spring-like arms 52b integral with thrust heads 5412 having external teeth 58b adapted to engage companion teeth in the cylinder sleeve 31b, the tapered surfaces 55b of the thrust heads engaging a companion tapered surface 56b on an expander ring 5712 hearing against the lower end of a two-piece ring 3a fitting within a peripheral groove 84a in the body b. The two-piece ring 83a is held in the groove by a solid ring 81:; disposed in a recess 82a in the former, this solid ring being engaged by a split expansible spring ring 105 which initially extends within'an internal groove 186 in the cylinder sleeve 31b. This spring ring 105 has an upper tapered surface 107 inclined in an upward and inward direction for engagement with a companion tapered surface 168 at the upper side of the shoulder groove 106. The split ring m5 engages a spring seat 199, against which bears the lower end of a helical compres sion spring 110, the upper end of which bears against the cylinder flange 70a.

As assurance that the pressure differential in the tub ing-casing annulus H can act in an upward direction on the piston 3512, a plurality of inlet ports 111 may be provided in the cylinder skirt below the piston. The usual working clearance between the expander 23d and the body ltlb of the tool should provide for the entry of fluid from the tubing-casing annulus H into the cylinder 32b and below the piston 35b, but the inlet ports 111 offer assurance that such fluid pressure will be present. Accordingly, the fluid under pressure in the tubing-casing annulus H is acting in an upward direction on the annular piston 35b and is acting in a downward direction on the cylinder 3% and the expander 23d, the cylinder flange 7&1 actually constituting an upper cylinder head over which the fluid pressure acts.

Fluid from the exterior of the apparatus is prevented from entering the cylinder space 3312 between the flange 76 a and piston 35!) by the seal rings 41, 43 on the piston engaging the body ltib and the cylinder skirt 31b, and by the aforementioned seal 1% in the flange or head 7 tla'engaging the periphery of the body.

In the use of the apparatus illustrated in FIGS. 8 and 9, the parts are initially in their retracted position disclosed in FIG. 8, in which the thrust heads 54b and arms 52b are retracted, the split retainer ring res being disposed in its groove 1%. The apparatus is lowered in the well casing to the desired setting point, after which the pressure in the tubing-casing annulus H is increased. This pressure will act in a downward direction over the crosssectional area of the cylinder flange or head 70a, tending to urge it in a downward direction. Such downward movement and corresponding downward movement of the expander 23d is at first prevented by the split ring 195 and also by the helical compression spring 110. However, when the pressure exceeds the force of the split ring 195, the inclined or cam surfaces m7, 108 shift the ring inwardly out of the groove 1%, the cylinder 32b and expander 23d then moving downwardly along the body 16b, the slips a and slip ring 17a also moving downwardly until the slip retainer ring engages the lower body coupling 12a, after which continued downward movement of the cylinder and expander will shift the expander 23d down along the slips 15a and the latter radially outwardly into anchoring engagement with the well casing C. At this time, the split retainer ring 105 merely slides relatively freely along the inner cylindrical wall of the cylinder sleeve 31b.

The external pressure differential is also acting in an upward direction over the piston portion 35b of the latch or coupling sleeve 34b, and will shift it upwardly along the body 1% to cause the body expander 57b to cam the thrust heads 54b outwardly, until the head teeth 58b are fully meshed with the companion teeth 5% on the cylinder sleeve 31b. A solid abutment is then formed between the body 10b of the tool and the expander 2365 through which downward forces or thrust on the body are transmitted to the slips 15a. Thus,'the downward forces will be transmitted from the body llila, through the two-piece ring d3a, to the expander and lock ring 5712, and from the latter through the thrust heads 54-!) to the cylinder sleeve 31b, such downward t'orce passing from the cylinder sleeve through the expander 23d to the slips 15a, and thence to the well casing C.

When the apparatus is to be released from the well casing, the pressure differential in the tubing-casing annulus H is relieved, which will allow the compression spring fill to expand, shifting the cylinder 32b and expander 23d upwardly, the cylinder sleeve 31b ratcheting past the thrust heads 54b until the split retainer ring again enters the groove 1%. During such upward movement, the expander 23d is moved upwardly relative to the slips 15a, the tapered tongue and groove interconnection 24, 25 between these parts effecting a full retraction of the slips 15a from the well casing back to their initial position disclosed in FIG. 8.

f the spring 119 is incapable of retracting the slips 1511, as, for example, due to some foreign material in the well casing, the fluid pressure need merely be relieved and a downward force imposed on the tubing string and the body ltlb of the tool connected thereto. The same action will occur on the thrust heads 54b as occurs in the other forms of the invention. The substantially lesser angle to the vertical of the coengaging tooth faces 58b, 5% as compared to the angle to the vertical between the mengaging expander and thrust head surfaces 56, 55b will cause the thrust heads 54b to be cammed inwardly from the cylinder, allowing the body 10b to move downwardly to the extent suflicient to bring its lower body shoulder 27b into engagement with the slip retainer ring 17a, exerting a downward pull on the slips 15a relative to the expander 23d and effecting their retraction.

The inventor claims:

1. In apparatus to be disposed within and anchored to a well conduit: body means; slip instrumentalities carried by said body means and adapted to engage the well conduit to anchor the body means therewithin; expander means slidable along said body means and adapted to coact with said slip instrumentalities to expand and hold said slip instrumentalities against the well conduit; means. for relatively shifting said expander means and slip instrumentalities to expand said slip instrumentalities. against the well conduit; means for transmitting longitudinal force directly from said body means to said expander means including a coupling member, first coengageable cam means on said body means and coupling member tending to urge said coupling member laterally outwardly in response to relative longitudinal movement between said body means and coupling member, second coengageable cam means on said coupling member and expander means tending .to urge said coupling member laterally inwardly in response to relative longitudinal movement between said expander means and coupling member, said first and second cam means being so constructed and arranged that one of said cam means exerts a greater lateral force than said other cam means to release said coupling member from one of said means in response to a longitudinal force imposed on one of said means.

2. In apparatus to be disposed within and anchored to a well conduit: body means; slip instrumentalities carried by said body means and adapted to engage the well con duit to anchor the body means .therewithin; expander means slidable along said body means and adapted to coact with said slip instrumentalities to expand and hold said slip instrumentalities against the well conduit; means for relatively shifting said expander means and slip instrumentalities to expand said slip instrumentalities against the well conduit; means for transmitting longituaoiijees ber, said expander means and coupling member having second coengageable tapered surfaces tending to urge said coupling member laterally inwardly in response to relative longitudinal movement between said expander means and coupling member, the angle of one of said coengageable tapered surfaces to the axis of said body means being substantially different than the angle of said other comgageable tapered surfaces to the axis of said body means to release said coupling member from one of said means in response to longitudinal force imposed on one of said means.

3. In apparatus to be disposed within and anchored to a well conduit: body means; slip instrumentalities carried by said body means and adapted to engage the well conduit to anchor the body means therewithin against longitudinal movement in one direction; expander means slidable along said bodymeans and adapted to coact with said slip instrumentalities to expand and hold said slip instrumentalities against the well conduit; means for relatively shifting said expander means and slip instrumentalities to expand said slip instrumentalities against the well conduit; means for transmitting.longitudinal force directly from said body means to said expander means including a coupling member, first coengageable cam means on said body means and coupling member tending to urge said coupling member laterallyoutwardly in response to movement of said body means in said one direction, second coengageable cam means on said coupling member and expander means tending to urge said coupling member laterally inwardly in response to longitudinal movement of said body means in said one direction, said first and second cam means being so constructed and arranged that one of said cam means exerts a greater lateral force than said other cam means to release said coupling member from one of said means in response to a force exerted by said body means in said one longitudinal direction. t t

4. in apparatus to be disposed within and anchored to "id- I said slip instrumentalities against the well conduit; means for relatively shifting said expander means and slip instru mentalities to expand said slip instrumentalities against the well conduit; means for transmitting longitudinal force directly from said body means to said expander means including a coupling member, said body means and coupling member having first coengageable tapered surfaces tending to urge said coupling member laterallyoutwardly in response to relative longitudinal movement between said body means and coupling member, said expander means and coupling member having second coengageable tapered surfaces tending to urge said coupling member laterally inwardly in response to relative longitudinal movement between said expander means and coupling member, the angle of said first coengageable tapered surfaces to the axis of said body means being substantially greater than the angle of said second coengageable tapered surfaces to the axis of said body means to release said coupling member from said expander means in response to longitudinal force imposed on said body means.

6. In apparatus to be disposed within and anchored, to

I a well conduit: bodymeans; slip ins-trumentalities carried by said body means and adapted to engage the well conduit to anchor the body means therewithin against longitudinal movement in one direction; expander means slidable along said body means and adapteclto coact with said slip instrumen-talities to expand and holdsaid slip instrumentalities against the well conduit; means for relatively shifting said expander means and slip instrumentalitiesto expand said slip instrumentalities against the well conduit; means for transmitting longitudinal force directly from said body means to said expander means I including a coupling member, said body means and coupling member having first coengageable tapered surfaces tending to urge said coupling member laterally outwardly in response to longitudinal movement of said body means in said one direction, said expander means and coupling member having second coengageable tapered surfaces tending to urge said coupling member laterally inwardly in response to longitudinal movement of said body means in said one direction, the angle of said first coengageable tapered'surfaces to the axis of said body means being substantially greater than the angle of said second coa well conduit: body means; slip instrumentalities carried by said body means and adapted to engage the well conduit to anchor the body means therewithin against longi tudinal movement in one direction; expander means slidable along said body means and adapted to coact with said slip instrumentalities to expand and hold said slip 'instrumentalities against the well conduit; means for relain response to longitudinal movement of said body means in said one direction, the angle of one of saidcoengageable tapered surfaces to the axis of said body means being substantially different than the angle of said other coengageable tapered surfaces to the axis of said body means to release said coupling member from one of said means in response to a force imposed by said body means in said one longitudinal direction.

5. In apparatus to be disposed within and anchored to a well conduit: body means; slip instmrnentalities carried by said body means and adapted to engage the well conduit to anchor the body means therewithin; expander means slidable along said body means and adapted to coact with said slip instrumentalities to expand and hold engageable tapered surfaces to the axis of said body means to release saidLcoupling member from said expander means in response to longitudinal force imposed on said body means and exerted in said one longitudinal direction.

7. In apparatus to be disposed within and anchored to a well conduit: a body; slip instrumentalities carried by said-body and adapted to engage the well conduit to anchor the body thcrewithin; expander means slidable along said body and adapted to coact with said slip instrumentalities to expand and hold said slip instrumentalities against the well conduit; hydraulically operable means for shifting said expander means along said body and slip instrumentali-ties to expand said slip; instrumentalities against the well conduit; means for transmitting longitudinal force directly from said body to said expander means including a coupling member having inner and outer tapered surfaces, said body engaging said inner tapered surface, said-expander means engaging said outer tapered surface, the angle of said inner tapered surface to the axis of said body being substantially greater than the angle of said outer tapered surface to the axis of said body to release said coupling member from said expander means in response to longitudinal force imposed on said body. I

8. In apparatus to be disposed within and anchored to a wellconduit: -a body; slip means carried by said body and adapted to engage the well conduit to anchor the body therewithin; an expander slidable along said body and adapted to coact with said slip means to expand and hold said slip means against the well conduit; a piston movably mounted on said body; a cylinder slidable along said piston and connected to said expander means; coupling means connected to said piston and disposed between said body and cylinder; said body and coupling means having first coengageable tapered surfaces tending to urge said coupling means laterally outwardly in response to movement of said piston on said body; said coupling means and cylinder having second coengageable tapered surfaces tending to urge said coupling means laterally inwardly in response to relative longitudinal movement between said expander and coupling means; the angle of said second tapered surfaces to the body axis being substantially less than the angle of said first tapered surfaces to the body axis to release sm'd coupling means from said cylinder in response to longitudinal force imposed on said coupling means by said body.

9. In apparatus to be disposed within and anchored to a Well conduit: a body; slip means carried by said body and adapted to engage the well conduit to anchor the body therewithin; an expander slidable along said body and adapted to coact with said slip means to expand and hold said slip means against the well conduit; a

piston movably mounted on said body; a cylinder slidable along said piston and connected to said expander means; coupling means connected to said piston and disposed between said body and cylinder; said body and coupling means having first coengageable tapered surfaces tending to urge said coupling means laterally outwardly in response to movement of said piston on said body; said coupling means and cylinder having second coengageable tapered surfaces tending to urge said coupling means laterally inwardly in response to relative longitudinal movement between said expander and coupling means;

the angle of said second tapered surfaces to the body axis being substantially less than the angle of said first tapered surfaces to the body axis to release said coupling means from said cylinder in response to longitudinal force imposed on said coupling means by said body; and releasable retainer means connected to said piston and engageable With said cylinder to prevent movement of said cylinder and expander means in a direction to expand said slip means.

1G. in apparatus to be disposed Within and anchored to a Well conduit: a body; slip means carried by said body adapted to engage the well conduit to anchor the body therewithin; an expander slidable along said body and adapted to coact with said slip means to expand and hold said slip means against the well conduit; a piston on said body; a cylinder slidable along said piston and connected to said expander; coupling means connecting said piston to said body; and releasable retainer means connected to said piston and engageable with said cylinder to prevent movement of said cylinder and expander in a direction to expand said slip means; said cylinder having means thereon subject to pressure in the well conduit to move said cylinder along said piston and said expander alon said body.

11. In apparatus to be disposed within and anchored to a well conduit: a body; slip means carried by said body and adapted to engage the well conduit to anchor the body therewithin; an expander slidable along said body and adapted to coact with said slip means to expand and hold said slip means against the well conduit; a cylinder connected to said expander; a coupling sleeve between said body and cylinder and connected to said body, said sleeve including a piston along which said cylinder is slidable and also including a retainer element releasably engaging said cylinder to initially prevent movement of said cylinder and expander in a direction to expand said slip means; said cylinder having means thereon subject to pressure in the well conduit to move :said cylinder along said piston and said expander along said body.

12. In apparatus to be disposed within and anchored to a well conduit: a body; slip means carried by said body and adapted to engage the well conduit to anchor the body therewithin; an expander slidable along said body and adapted to .co'act with said slip means to expand and hold said slip means against the Well conduit; a cylinder connected to said expander; said body having an expander surface thereon; said cylinder having a retractor surface thereon; a coupling sleeve between said body and cylinder including a piston along which saidcylinder is slidable, thrust elements engaging said expander surface and engageable with said retractor surface, and retainer elements releasably engaging said cylinder to initially prevent movement of said cylinder and expander in a direct on to expand said slip means; the angle of inclination of said expander surface to the body axis being substantially greater than the angle of inclination of said retractor surface to the body axis; said cylinder having means thereon subject to pressure in the Well conduit to move said cylinder along said piston and said expander along said body.

13. In apparatus to be disposed Within and anchored to a well conduit: body means; slip iustrumentalities carried by said body means and adapted to engage the well conduit to anchor the body means therewithin against upward movement; expander means slidable upwardly along said body means and adapted to coact with said slip instrumentalities to expand and hold said slip instrumentalities against the well conduit; hydraulically operable means responsive to the pressure of the fluid within said body means for shifting said expander means upwardly along said slip instrumentalities to expand said slip instrumentalities against the well conduit; means for transmitting upwardly directed forces directly from said body means to said expander means including a coupling member, first coengageable cam means on said body means and coupling member tending to urge said coupling member laterally outwardly in response to upward movement of said body means along said coupling member, second coengageable cam means on said coupling member and expander means tending to urge said coupling member laterally inwardly in response to upward movement of said coupling member with respect to said expander means, said first and second cam means being so constructed and arranged that one of said cam means exerts a greater lateral force than said other cam means to release said coupling member from one of said means in response to an upward force imposed on one of said means.

14. In apparatus to be disposed within and anchored to a well conduit: body means; slip instrumentalities carried by said body means and adapted to engage the well conduit to anchor the body means therewithin against downward movement; expander means slidable downwardly along said body means and adapted to coact with said slip instrumentalities to expand and hold said slip instrumentalities against the Well conduit; hydraulically operable means responsive to the pressure of fluid externally thereof for shifting said expander means downwardly along said slip instrumentalities to expand said slip instrumentalities against the well conduit; means for transmitting downward force directly from said body means to said expander means ncluding a coupling member, first coengageable cam means on said body means and coupling member tending to urge said coupling member laterally outwardly in response to downward movement of said body means with respect to said coupling member, second coengageable cam means on said coupling member and expander means tending to urge said coupling member laterally inwardly in response to downward movement of said coupling member with respect to said expander means, said first and second cam means being so constructed and arranged that one of said cam means exerts a greater lateral force than said other cam means to release said coupling member from one of said means in response to a downward force imposed on one of said means.

15. In apparatus to be disposed within and anchored to a well conduit: a body; slip means carried by said body and adapted to engage the well conduit to anchor the body against upward movement therewithin; an expander slidable upwardly along said body and adapted to coact with said slip means to expand and hold said slip means against the well conduit; a piston movably mounted on said body; a cylinder slidable upwardly along said piston and connected to said expander; coupling means connected to said piston and disposed between said body and cylinder; said body and coupling means having first coengageable tapered surfaces tending to urge said coupling means laterally outwardly in response to relative downward movement of said piston on said body; said coupling means and cylinder having second coengageable tapered surfaces tending to urge said coupling means laterally inwardly in response to upward movement of said coupling means relative to said cylinder means, the angle of said second tapered surfaces to the body axis being substantially less than the angle of said first tapered surfaces to the body axis to release said coupling means from said cylinder in response to an upward force imposed on said coupling means by said body, said body having a port therein for conducting fluid from the interior of said body into said cylinder above said piston to urge said cylinderand expander upwardly along said body and slip means.

16. In apparatus to be disposed within and anchored to a well conduit: a body; slip means carried by said body and adapted to engage the well conduit to anchor the body against downward movement therewithin; an expander slidable downwardly along said body and adapted to coact with said slip means to expand and hold said slip means against the well conduit; a piston movably mounted on said body; a cylinder responsive to the pressure of fluid externally thereof and slidable downwardly along said piston by such fluid under pressure and connected to said expander to shift said expander downwardly along said body and slip means; coupling means connected to said piston and disposed between said body and cylinder; said body and coupling means having first coengageable tapered surfaces tending to urge said coupling means laterally outwardly in response to relative upward movement of said piston on said body; said coupling means and cylinder having second coengageable tapered surfaces tending to urge said coupling means laterally inwardly in response to relative downward movement of said coupling means with respect to said cylinder means, the angle of said second tapered surfaces to the body axis being substantially less than the angle of said first tapered surfaces to the body axis to release said coupling means from said cylinder in response to downward force imposed on said coupling means by said body.

17. In apparatus to be disposed within and anchored to a well conduit: a body; slip means carried by said body and adapted to engage the well conduit to anchor the body therewithin; an expander slidable along said body and adapted to coact with said slip means to expand and hold said slip means against the well conduit; a piston movably mounted on said body; a cylinder slidable along said piston and connected to said expander; coupling means connected to said piston and disposed between said body and cylinder; said body and coupling means having first coengageable tapered surfaces tending to urge said coupling means laterally outwardly in response to movement of said piston on said body; said coupling means and cylinder having second coengageable tapered surfaces tending to urge said coupling means laterally inwardly in response to relative longitudinal movement between said expander and coupling means; the angle of said second tapered surfaces to the body axis being substantially less than the angle of said first tapered surfaces to the body axis to release said coupling means from said cylinder in response to longitudinal forces imposed on said coupling means by said body; and releasable retainer means interconnecting said body and cylinder to prevent movement of said cylinder and expander in a direction to expand said slip means; said cylinder having means thereon subject-to pressure in the well conduit to move said cylinder along said piston and said expander along said body.

18. In apparatus to be disposed within and anchored to a well conduit: body means; slip instrumentalities carried by said body means and adapted to engage the well conduit to anchor the body means therewithin; expander means slidable along said body means and adapted to coact with said slip instrumentalities to expand and hold said slip instrumentalities against the well conduit; spring means disposed between and engaging said expander means and slip instrumentalities and tending to shift them in longitudinal direction away from each other to urge said slip instrumentalities toward a retracted position; hydraulically operable cylinder and piston means for relatively shifting said expander means and slip instrumentalities against the force of said spring means to expand said slip instrumentalities against the well conduit; said body means having a side port for feeding fluid under pressure from the interior of said body means to said hydraulically operable cylinder and piston means.

19. In apparatus to be disposed within and anchored to a well conduit: a body; slip means carried by said body and adapted to engage the well conduit to anchor the body therewithin; an expander slidable along said body and adapted to coact with said slip means to expand and hold said slip means against the well conduit; a piston on said body; a cylinder slidable along said piston and connected to said expander; coupling means connecting said piston to said body; and releasable retainer means connected to said piston and engageable with said cylinder to prevent movement of said cylinder and expander in a direction to expand said slip means; said cylinder having a portion responsive to fluid pressure to slide said expander along said body and expand said slip means.

References Cited in the file of this patent UNITED STATES PATENTS 2,187,482 Baker et al. Jan. 16, 1940 2,345,873 Hart Apr. 4, 1944 2,735,497 Brumleu Feb. 21, 1956 2,756,827 Farrar July 31, 1956 2,874,784 Baker et al. Feb. 24, 1959

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