US2713910A

US2713910A - Releasable operating devices for subsurface well tools

Info

Publication number: US2713910A
Application number: US168966A
Authority: US
Inventors: Reuben C Baker; Martin B Conrad
Original assignee: Baker Oil Tools Inc
Current assignee: Baker Hughes Oilfield Operations LLC
Priority date: 1950-06-19
Filing date: 1950-06-19
Publication date: 1955-07-26
Anticipated expiration: 1972-07-26

Description

Jufly 26, 1955 R. c. BAKER ETAL RELEASABLE OPERATING DEVICES FOR SUBSURFACE WELL TOOLS Filed June 19, 1950 3 Sheets-Sheet l p3 in AWN .3 m a; 87 Z M JQTTOENEY- July 26, 1955 c, BAKER ETAL RELEASABLE OPERATING DEVICES FOR SUBSURFACE WELL TOOLS 3 SheetsSheet 2 Filed June 19, 1950 Rev/551v C. B

MAe-rnv Arrow/EV.

July 26,- 1955 c, BAKER ET AL 2,713,910

RELEASABLE OPERATING DEVICES FOR SUBSURFACE WELL TOOLS Filed June 19, 1959 3 Sheets-Sheet 3 0 9 A 1 a E AA. w M WM 1 6 3mm \x 9 .m @W/&%w 5w. F M I C 5 B 0 2 2 0 1 7 "w 4 I a 3 Eff figzwmi i W 0 A \d. 10 7 1 A r x Q m L K 2 a w E if 3&5? B E E w w E, H J E W m H D s 1 37% 4 kl 4 l I." NE \NNDI L E v w Z c fif w United States Patent RELEASABLE OPERATING DEVICES FOR SUBSURFACE WELL TOOLS Reuben C. Baker, Coalinga, and Martin B. Conrad, Huntington Park, Califl, assignors to Baker Oil Tools, Inc., Vernon, Califl, a corporation of California Application June 19, 1950, Serial No. 168,966 22 Claims. (Cl. 166-123) The present invention relates to the setting or operating of well tools in casing, liners and similar conduits positioned in well bores, as well as in open well bores.

It is sometimes desirable to run and set a well packer in a well bore on a wire line, since the time consumed in performing such operations, including the removal of the wire line from the well bore, is substantially decreased when compared with performance of the same operations through use of a tubular string. Devices are known for accomplishing the wire line operations, but the packer does not have an open passage through which fluent substances can be pumped subsequently, if need be.

Accordingly, it is an object of the present invention to provide an apparatus for running and setting a well packer or other well tool in a well bore on a wire or flexible line, in which the passage through the packer or tool is open after the setting operation is performed and the wire line equipment removed from the well bore.

Another object of the invention is to provide a wire line setting tool and well packer combination in which the tool can be firmly secured to the packer, despite the presence of a small passage through the latter to insure its safe running and proper setting in the well bore, the setting tool being automatically and completely released from the set packer to provide an open passage through it through which fluent substances can be pumped.

A further object of the invention is to threadedly connect a wire line setting tool to a well packer, the setting tool being fully releasable from the latter.

Yet another object of the invention is to threadedly connect a setting tool to a well packer, in which the threaded portion of the tool is disconnectible from the companion threaded portion of the packer to release the tool from the packer after the tool has fully set the packer in the well bore, without the necessity for rotating the setting tool. In a more limited sense, the threaded portion of the setting tool is retracted from threaded engagement with the packer to effect release of the connection between the two devices.

Still a further object of the invention is to threadedly connect a setting tool to a well packer and positively retract the threaded portion of the tool from the companion threaded portion of the packer, to uncouple the two devices from each other after the tool has set the packer in the well bore.

Another object of the invention is to provide a setting tool that can be threaded into a well packer, or other well tool, to connect the same together, and which need not be rotated to disconnect the two from one another.

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, 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 the drawings:

Figure l is a longitudinal section illustrating a coupling device for securing the lower portion of a setting tool to the upper portion of a well packer;

Fig. 2 is a view similar to Fig. 1, with the coupling device in released position;

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

Fig. 4 is a cross-section taken along the line 44 on Fig. 1; I v

Fig. 5 is a cross-section similar to Fig. 4, with the coupling device detached from the well tool;

Fig. 6 is a view similar to Fig. 1 of another embodiment of coupling device for securing the lower portion of a setting tool to a well tool, such as a packer;

Fig. 7 is. a view similar to Fig. 6, illustrating the coupling device in released position;

Fig. 8 is a cross-section taken along the line 8-8 on Fig. 6;

Fig. 9 is a cross-section taken along the line 9-9 on Fig. 6;

Figs. 10 and 1011 together constitute a longitudinal section through a complete well apparatus embodying the coupling device shown in Figs. 1 to 5, inclusive, Fig. 10a constituting a lower continuation of Fig. 10;

Fig. 11 is a cross-section taken along the line 11-11 on Fig. 10. 1

In the forms of the invention disclosed in the drawings, it is desired to run a subsurface well tool A, such as a well packer, to a desired location in a well casing B disposed within a bore hole. The packer is then anchored in packed-elf condition against the well casing through use of a setting tool C connected to it. This setting tool is attached to the lower end of a runningin string D, such as a wire line, extending to the top of the well bore.

The packer includes a tubular body member 10 having an abutment or valve housing 11 threaded onto its lower end and a trip ring 12 slidable along the body at its upper portion. A set of upper segmental slips 13 is disposed around the body immediately below the trip ring 12. These slips are held initially in retracted position by shear screws 14 securing them to an upper conical expander 15 initially attached to the body 10 by one or more shear screws 16. The converging sur faces 17, 18 of the upper set of slips and upper expander are so disposed with. respect to one another as to secure the packer against movement in an upward direction within the casing B, following outward expansion of the slips 13 into engagement with the casing.

A set of lower segmental slips 19 is provided adjacent the body housing 11, and these slips are also secured by shear screws 20 to a lower tapered expander 21 attached initially to the body by one or more shear screws 22. The direction of taper on the exterior 23 of the lower expander 21 and the taper on the cooperable surfaces 24 of the lower slips 19 are such as to hold the well packer A against movement in a downward direction following expansion of the slips 19 outwardly against the casing B.

A suitable lock is provided between the body 10 and the lower expander 21, to permit upward movement of the body within this expander and to preclude its relative downward movement. This lock may be of any operable form. In the drawings, it is illustrated as including a split wedge ring 25 received within a groove 26 in the lower expander and engageable with the downwardly facing ratchet teeth 27 on the body.

A suitable packing 28, such as a packing sleeve of rubber or similar pliant, elastic material, is disposed around the body between the upper and

lower expanders

15, 21. The ends of the packing sleeve 28 are received within annular pockets 29 formed between the expander skirts 30 and the exterior of the body 10.

In setting the packer A, a downward force is exerted on the upper trip ring 12 of sutficient extent to shear the screws 14 attaching the upper slips 13 to the upper expander 15. These slips are then moved downwardly along the upper expander and radially outward into anchoring engagement with the well casing. Such outward expansion of the upper slips 13 can occur, since their shear screws 14 have a lesser combined shear value than the screws 16 attaching the upper expander 15 to the packer body 10. These last-mentioned screws, in turn, have a lesser shear value than the screws 22, holding the lower expander 21 to the body and the lower slips 19 to the lower expander.

After the upper slips 13 have been engaged with the well casing, an upward strain or pull is imparted to the packer body 10, which shears the screws 16 holding the 1 upper expander 15 to the body, and moves the lower expander 21 and lower slips 19 with the body toward the upper expander 15. This action foreshortens the packing sleeve 28 and compresses it outwardly into firm sealing engagement with the wall of the casing B.

Thereafter, an increase in the upward pull or force on the packer body 10 substantially simultaneously shears the

screws

22, 20 holding the lower expander 21 to the body 10 and the lower slips 19 to the lower expander, causing the lower body housing 11 to shift the lower slips 19 upwardly along the lower expander 21 and radially out ward into anchoring engagement with the casing Wall. The wedge lock ring 25 then engages the ratchet teeth 27 formed on the'body, to lock the latter against downward movement, since such downward movement is transmitted through the lower expander 21 and lower slips 19 to the well casing B. Upward movement of the body 10 is resisted by engagement of the lower housing 11 with the lower slips 19, the upward force being transmitted from the latter, through the lower expander 21, packing sleeve 28, upper expander 15 and upper slips 13 to the well casing.

In the manner just described, the 'well packer A is anchored in packed-off condition against longitudinal movement in both directions within the well casing B.

The well packer disclosed is designed to enable fluid to be pumped through its central bore or passage 31. This bore or passage can be closed to prevent return flow of fluids in an upward direction through it, by providing a buoyant back pressure valve ball 32 in the housing that is movable upwardly into engagement with a valve seat 33 in the lower end of the body 10. This ball cannot close the outlet from the valve housing 11, since it comes to rest upon a plurality of spaced housing ribs 34.

It is desired to provide an arrangement which will enable the well packer A to be run in the well casing B in a rapid manner. Such expeditious lowering of the well packer in the well casing can be accomplished through use of the wire line D. It is desired to set the packer fully and firmly against the casing without imposing a strain on the wire line. A substantially large strain or pull on the packer parts may be required, and, for this reason, the setting mechanism C must be capable of transmitting a large force and of releasing itself automatically from the well packer when the desired maximum force has been exceeded. In addition, it is desired to have an unobstructed central passage 31 through the well packer after the setting operation has been performed, in order to permit subsequent re-connection of a tubular string (not shown) to the well packer A, for the purpose of pumping cementitious materials, or other substances, through the tubular string and well packer, or for the purpose of employing the packer for producing oil, gas, and the like, from the well bore below the well packer.

The above purposes are accomplished with the equiptil ment disclosed in the drawings. As shown, setting of the well packer is dependent upon the development of a gas pressure within the setting tool C that is secured initially to the well packer. This gas pressure is developed within the upper portion of a cylinder 35 that has a head 36 suitably secured to the wire line D, which may have an electrically conductive core 37.

The motivating gas under pressure is generated in the cylinder 35 above a piston 38 slidably mounted therein. This piston is threadedly connected to a piston rod 39 extending downwardly through a lower cylinder head 40 to a point therebelow, where an anvil or cross-piece 41 is mounted within a transverse slot 42 in the rod. Leakage between the rod 39 and lower cylinder head 40 is prevented by suitable rod packing 43, whereas leakage around the piston 38 is prevented by suitable piston rings 44 slidably engaging the wall of the cylinder.

In order to set the packer in the manner described above, a downward force is to be imposed upon the trip ring 12 and the upper slips 13, and the packer body 10 is to be moved relatively in an upward direction. To accomplish this purpose, a tubular actuating mandrel 45 is threadedly connected to the lower cylinder head 4%, the lower end of this mandrel being coupled to the packer body through the agency of a suitable releasable adapter or connecting device E. As specifically disclosed, the lower end of the mandrel 45 is threaded into a tension head member 46 having an inwardly directed flange 47 that serves to clamp a threaded flanged collar 48 against the lower end of the mandrel 45. A release stud 49 is threaded into the collar 48, with its lower portion threaded into the upper end of a shank 50 depending into the upper portion of the packer body 10. The intermediate portion 51 of the release stud is reduced in diameter, to insure its pulling apart at that point, when sufficient tensile strain is taken upon it, as described hereinafter.

Onto the lower end of the shank 59 is threaded a retaining abutment or head 52 having an upward and inwardly directed tapered exterior 53 engaging companion tapered surfaces 54 on the heel portion of circumferentially spaced inherently contractile threaded dogs 55 carried by the leg portions 56 of a sleeve 57 which surrounds the shank 50 and extends upwardly into the tension head 46 below its flange 47. In effect, the threaded sleeve 57 has a plurality of longitudinally extending slots 58 formed through its wall to provide the plurality of circumferentially spaced legs 56 and threaded dogs 55. The threads 59 on the dogs may be placed in threaded engagement with the left-hand threads 60 formed in the upper end of the body 10. However, the legs 56 and dogs 55 tend to retract to an extent sufiicient to remove the external thread 59 completely from engagement with the companion threads 69 in the packer body 10;

When the release stud 49 is intact, the shank 50 is disposed in an upward position, with the upper end 53 of the retaining head 52 engaging the tapered heels 54 of the dogs 55, holding the latter outwardly with their threaded portions 59 firmly engaged with the packer body thread 6%, as illustrated in Fig. 1. In efiect, when the tension stud 49 is intact, the parts function as a single unit, permitting the sleeve device 57 to be threaded into the packer body 10. To facilitate such threading, a twopart or split ring 61 is clamped to the lower end of the tension head 46 by a nut 62 threaded onto the latter. This collar 61 projects laterally into the tension head 46 and extends below a shoulder 63 formed at theupper portion of the threaded sleeve 57. The split ring 61 also has a key 64 projecting inwardly into one of the slots 58 between adjacent depending legs 56, in efieet forming a key connection between the tension head 46 and the threaded sleeve 57. Such connection permits the tension head 46 to be grasped by hand, or a suitable tool, and

turned in the proper direction, to thread the dogs 55 into the packer body 10. The turning effort is transmitted from the-tension head 46 to the dogs 55 through the agency of the split ring 61 and its key 64.

It is apparent that the adapter device B provides a threaded and firm connection between the actuating mandrel 45, which is secured to the lower end of the cylinder 35, and the packer body 10.

The piston rod 39 is movable downwardly within the bore 65 of the actuating mandrel 45, the cross-piece 41 projecting through diametrically opposed longitudinally extending slots 66 formed through the mandrel wall. The cross-piece also extends into the opposed slots 67 formed through a setting ring or sleeve 68 slidably mounted on the actuating mandrel 45, to form a connection between the piston rod 39 and the setting ring. A setting skirt 69 is adjustably threaded on the setting ring 68, this skirt having a sleeve-like extension 70 threaded on its lower end and resting on top of the upper trip ring 12.

As stated above, a force or pressure is imposed upon the piston 38, which moves the piston and piston rod 39 downwardly, and the cylinder 35 in a relative upward direction. The downward force of the rod 39 is transmitt-ed to the trip ring 12 through the anvil 41, setting ring 68, sleeve 69 and skirt 70; whereas, the upward movement of the cylinder 35 is transmitted to the packer body through the actuating mandrel 45, tension head 46, collar 48, release stud 49, shank 50, retaining abutment 52 and threaded dogs 55. It is apparent that the development of suflicient pressure in the cylinder 35 acting upon the piston 38 will eventually shear the screws 14 holding the upper slips 13 to the expander and move the slips 13 outwardly against the casing B. Thereafter, the cylinder 35 will move upwardly to urge the body 10 in the same direction, for the purpose of expanding the packing sleeve 28 against the casing, and the lower slips 19 against the casing, in the manner described above.

In order to obtain the desired operational sequence, a combustible fuel or power charge 71 may be contained within the upper end of the cylinder 35. The combustion charge 71, such as a railway flare of cylindrical or stick form, is placed in the upper head end 36 of the cylinder. The charge is ignited by a blank cartridge 72 contained within the upper cylinder head. The wire line running-in string D is suitably attached to the head 36, in a known manner, and has the lower end of its electrically conductive wire or core 37 connected electrically to a heating filament 73 in the cartridge 72.

When the combustible fuel or power charge 71 is ignited, evolved gas under pressure is produced within the cylinder. This gaseous force acts downwardly. on. the piston 38 and exerts a reactive upward force on the cylinder head 36, urging the piston 38 downwardly and the cylinder 35, and the parts connected thereto, in an upward direction.

The apparatus is lowered in the well bore, with the parts in a position shown in Figs. 1, 3 and 4. When the depth in the casing B is reached at which the well packer A is to be set, the electrical circuit through the cartridge filament 73 is completed, which fires the cartridge 72. The flame issuing therefrom ignites the upper end of the power charge 71, initiating its combustion. This charge contains its own source of oxygen. to support combustion. As combustion proceeds, a gaseous pressure is developed within the cylinder 35, exerting a downward force on the piston 33 and rod 39, which is transmitted through the cross-piece 41, setting ring 68, setting sleeve 69 and skirt 70 to the packer trip ring 12 and the upper slips 13. When sutficient pressure has been developed in the cylinder 35 to overcome the shear strength of the shear screws 14, the slips 13 are released from the expander 15 and are pushed downwardly along the latter into outward engagement with the casing B.

As the combustible charge 71 continues to burn, the gas pressure within the cylinder 35 increases to a further extent, and this increased pressure is transmitted to the piston 38. Since the upper slips 13 are wedged against the casing, the piston cannot move downwardly to any further appreciable extent. Instead, the cylinder 35, actuating mandrel 45, tension head 46, collar 48, stud 49, shank 50, retaining head 52, threaded dogs 55 and packer body 10 are urged in an upward direction. When the pressure within the cylinder is increased sufficiently to overcome the shear strength of the screws 16 holding the upper expander 15 to the body 10, such screws are disrupted and the packer body 10 is moved upwardly within the upper expander 15 to compress the rubber packing sleeve 28 between the upper and

lower expanders

15, 21, forcing it outwardly into firm sealing engagement with the casing wall.

Further increase in the cylinder gas pressure, as a result of the continued combustion of the charge 71, effects shearing of the

screws

22, 20 attaching the lower expander 21 to the body 10 and the lower slips 19 to the lower expander, allowing the cylinder 35 to move upwardly and carry the body It) and lower slips 19 in an upward direction, to shift the latter radially outward into engagement with the casing B.

The pressure in the cylinder 35 continues to increase, as combustion of the charge 71 proceeds, and all of the packer elements are engaged more firmly with the casing. It is to be noted that the upward force between the actuating mandrel 45 and the packer body 10 is being transmitted through the tension stud 49. When the pressure exceeds the tensile strength of the reduced diameter portion 51 of this stud, the latter is pulled apart at such reduced diameter portion, to effect automatic release of the setting tool C from the well packer A.

Such release occurs as a result of actions now to be described. When the tension stud 49 is pulled apart, the shank 50 and retaining abutment or head 52 can drop downwardly, to remove the head 52 from wedging engagement within the threaded dogs 55. Since the dogs and their legs 56 tend to retract inherently, the downward dropping of the head 52 away from the dogs allows the latter to' snap inwardly to the extent in which their threaded portions 59 are completely out of threaded engagement with the left-hand thread 60 in the body 10, as represented in Fig. 2. This eifects a complete release of the setting tool C from the well packer A, allowing the wire line D to be elevated, carrying the entire setting tool upwardly with it. During such upward movement, the split ring 61 secured to the tension head 46 engages the shoulder 63 on the split threaded sleeve 57, in order to pull the latter upwardly out of the packer body 10. In addition, it is to be noted that the extent of dropping of the shank 50 and head 52 is limited by engagement of a downwardly facing shoulder 74 on the shank 50 with an upwardly facing shoulder 75 on the threaded dogs 55. These

shoulders

74, 75 are preferably tapered in an upward and inward direction, so that the shank shoulder 74 tends to hold the threaded dogs 55 in an inward direction, and precludes their inadvertent outward shifting.

The entire setting tool C may now be removed from the well bore, leaving the packer A anchored in packedotf condition within the well casing B, with the passage 31 through the body unobstructed. After the setting tool and wire line have been removed from the well casing, a tubing string (not shown) may be lowered through the well casing for threaded attachment to the upper end of the well packer body 10. Fluent substances can now be pumped down through the tubing string and the well packer, return flow of such substances being prevented by upward engagement of the valve ball 32 with the body seat 33.

Another embodiment of the adapter for connecting the actuating mandrel 45 to the packer body member 10 is illustrated in Figs. 6 to 9. In this modification, the locking dogs 55a are held firmly outwardly in threaded engagement with the well packer A, and are positively retracted from such threaded engagement following disruption of the tension stud 49.

The actuating mandrel of the setting mechanism C is threaded into the tension head member 46a, which serves to clamp the threaded collar 48a to the latter. The release stud 49 is threaded into the collar 48a, with its lower portion threaded into a plug 80 which is, in turn, threaded into the upper end of the split threaded sleeve 57a having the depending legs 56a and the locking dogs a. In the present instance, the legs 56:: and dogs 55a tend to inherently expand, so as to hold the outer threaded portions 59a of the dogs in threaded engagement with the left-hand threads 60 of the packer body 10.

The dogs 55a are held positively in an outward direction by a backing sleeve 81 having an enlarged upper portion 82 provided with a cylindrical periphery 83 engaging the rear wall 84 of the expansible dogs. The lower portion 85 of the sleeve is of substantially smaller diameter than the cylindrical portion 83, fitting snugly within a lower backing wall 36 in the dogs 55a. This portion 86 of the dogs extends inwardly to a substantial extent beyond the upper portion 84 of the threaded dogs.

The sleeve 81 is threaded upon a rod 87, which has a nut 88 threaded on its upper end provided with a plurality of wings 89a projecting outwardly through the slots 58a between adjacent dogs 55a, and into a retrieving sleeve 89 threaded onto the tension head 46a and depending therefrom. This latter sleeve 89 has an inwardly directed shoulder 90 located immediately under the external portions of the wings 89a, and preferably in contact therewith.

The lower end of the rod 87 carries a head 91 within the packer body 10, upon which a spring seat 92 rests, engaged by a helical compression spring 93 extending upwardly into a retracting sleeve 94. The lower end of l the retracting sleeve 94 is spaced above the seat or washer 92, whereas its upper end has a frusto-conical inner surface 95 diverging in an upward direction, and adapted for engagement with companion surfaces 96 formed on the exteriors or" the foot portions 97 of the locking dogs 55a.

The parts are so arranged that the gap or space between the washer 92 and the lower end of the retracting sleeve 94 is slightly greater than the distance that the backing sleeve 81 must move upwardly, to remove it from backing engagement with the rear walls 84, 86 of the locking dogs 55a. After the backing sleeve has been elevated sufficiently out of the threaded dogs 55a, so as not to restrain their inward movement, the spring seat 92 engages the retracting sleeve 94 and shifts it upwardly to dispose its frusto-conical surface 95 over the dog feet 97. Such upward motion forcibly retracts the dogs 55a from threaded engagement with the upper end 60 of the packer body 10.

The adapter assembly is arranged with its parts in the position shown in Fig. 6, and the assembly is inserted into the upper end of the packer A and its dogs 55a threaded into the companion left-hand thread 60 in the packer body it as by applying a force to the tension head 46a, which turning effort is transmitted through the tension stud 49 and plug 80 to the threaded sleeve dogs 55a. The actuating mandrel 45 is then threaded into the upper end of the tension head 46a and the entire setting tool C properly arranged for running the equipment in the well bore on the wire line D.

When the setting point in the well casing has been reached, combustion of the charge 71 is initiated, the setting sleeve 70 being forced downwardly to shift the upper slips 13 against the casing B, and the actuating mandrel 45 moved or urged upwardly, its force being transmitted to the packer body 10 through the tension head 46a, tension stud 49, plug 80 and threaded sleeve 57a and its dogs 55a. These dogs 55a tend to expand outwardly and are prevented from moving inwardly by the backing sleeve 81 (see Fig. 6).

After the packer A has been fully set, the imposition of a sufficient force on the release stud 49 will disrupt it at its reduced diameter portion 51, allowing the actuating mandrel 45, tension head 46a and retrieving sleeve 89 to move upwardly relative to the threaded sleeve 57a. Such upward movement causes the retrieving sleeve 89 to carry the wing nut 88, rod 87 and backing sleeve 81 upwardly with it. The retracting sleeve 94 cannot at first move upwardly, since it engages the tapered feet 97, and the disposition of the backing sleeve 81 within the dogs 55a prevents the latter from being retracted. Upon removal of the backing sleeve 81 from holding relation behind the locking dogs 55a, however, the thrust washer 92 can engage the lower end of the retracting sleeve 94, the latter being then movable upwardly with the rod 87, its tapered surface 95 sliding longitudinally along the tapered feet 97 of the dogs, springing the latter forcibly inwardly to an extent in which their external thread 59a is completely disengaged from the internal thread 60 in the packer body 10. This condition is exemplified in Fig. 7. The entire setting tool C may now be removed from the well casing B, leaving the well packer A with an unobstructed central passage 31 through its body 16, and in a condition for subsequent coupling of a tubing string, or the like, to the packer.

The inventor claims:

1. In apparatus of the character described: a first member having a thread; a second member; an inherently contractible latch member carried by said second member and having a thread companion to said first member thread and meshable therewith; said latch member being inherently contractible inwardly to an extent sufiicient to bring its thread out of threaded engagement with said first member thread to enable said latch member and first member to be moved longitudinally and without rotation with respect to each other; means for holding said latch member in threaded engagement with the thread of said first member; and means enabling said holding means to be shifted longitudinally out of holding relation to said latch member to allow said latch member to contract inherently out of threaded engagement with said first member thread 2. In apparatus of the character described: a first member having a thread; a second member; a latch member carried by said second member and having a thread companion to said first member thread and engageable there with, said latch member being rotatable relative to said first member to thread it along said first member thread; said latch member having spring characteristics and being movable laterally inherently to an extent sufiicient to bring its thread out of threaded engagement with said first member thread to enable said latch member and first member to be moved longitudinally and without rotation with respect to each other; means for holding said latch member in threaded engagement with the thread of said first member; and means for enabling said holding means to be shifted longitudinally out of holding relation to said latch member to allow said latch member to spring inherently out of threaded engagement with said first member thread.

3. In apparatus of the character described: a first member having a thread; a second member; an inherently contractible latch member carried by said second member and having a thread companion to said first member thread and meshable therewith; said latch member being inherently contractible to an extent sufficient to bring its thread out of threaded engagement with said first member thread to enable said latch member and first member to be moved longitudinally and without rotation with respect to each other; means for holding said latch member in threaded engagement with the thread of said first member; and means releasably connecting said holding means to said second member, said connecting means being released to enable said holding means to be shifted out of holding relation to said latch member to allow said 4. In apparatus ofthe char.zcter described: a first member having a thread; a second member; a latch member carried by said second member and having a thread companion to said first member thread and engageable therewith; said latch member having spring characteristics and being movable laterally inherently to an .extent sufficient to bring its thread out of threaded engagement with said first member thread to enable said latch member and first member to be moved longitudinally and without rotation with respect to each other; means for holding said latch member in threaded engagement with the thread of said first member; and means releasably connecting said holding means to said second member, said connecting means being released to enable said holding means to be shifted out of holding relation to said latch member to allow said latch member to spring inherently out of threaded engagement with said first member thread.

5. In apparatus of the character described: a first member having a thread; a second member; a latch member carried by said second member and having a thread companion to said first member thread and engageable therewith; said latch member having spring characteristics and being movable laterally inherently to an extent suflicient to bring its thread out of threaded engagement with said first member thread to enable said latch member and first member to be moved longitudinally and without rotation with respect to each other; means for holding said latch member in threaded engagement with the thread of said first member; and a readily, breakable connection releasably connecting said holding means to said second member, breaking of said connection enabling said holding means to be shifted outof holding relation to said latch member to allow said latch member to spring inherently out of threaded engagement with said first member thread.

6. In apparatus of the character described: a first member; a second member; an inherently contractible latch member carried by said second member, said latch member being inherently contractible to an extent sufficient to bring it out of coupling engagement with said first member; means for holding said latch member outwardly in coupling engagement with said first member; and a readily breakable connection releasably connecting said holding means to said second member, breaking of said connection enabling said holding means to be shifted out of holding relation to said latch member to allow said latch member to contract out of coupling engagement with said first member.

7. In apparatus of the character described: a first member having a thread; a second member; a spring-like expansible and contractible latch member carried by said second member and having a thread companion to said first member thread and engageable therewith, said latch member being rotatable relative to said first member to thread it along said first member thread; said latch member being movable laterally with respect to said second member to an extent sufficient to bring its thread out of threaded engagement with said first member thread to enable said latch member and first member to be moved longitudinally and without rotation with respect to each other; and means engageable with said latch member for positively holding said latch member out of threaded engagement with the thread of said first member.

8. In apparatus of the character described: a first member having a thread; a second member; a spring-like expansible and contractible latch member carried by said second member and having a thread companion to said first member thread and engageable therewith, said latch member being rotatable relative to said first member to thread it along said first member thread; said latch memher being movable laterally with "respect to said second member to an extent suificient to bring its thread out of threaded engagement with said first member thread to enable said latch member and first member to be moved longitudinally and without rotation with respect to each other; means for holding said latch member in threaded engagement with the thread of said first member; and means engageable with said latch member for positively holding said latch member out of threaded engagement with the thread of said first member.

9. In apparatus of the character described: a first member having a thread; a second member; a spring-like expansible and contractible latch member carried by said second member and having a thread companion to said first member thread and engageable therewith; said latch member being movable laterally with respect to said second member to an extent suflicient to bring its thread out of threaded engagement with said first member thread to enable said latch member and first member to be moved longitudinally and without rotation with respect to each other; and means for positively shifting said latch member laterally of said second member and out of threaded engagement with the thread of said first member.

10. In apparatus of the character described: a first member having a thread; a second member; a spring-like expansible and contractible latch member carried by said second member and having a thread companion to said first member thread and engageable therewith; said latch member being movable laterally with respect to said second member to an extent sulficient to bring its thread out of threaded engagement with said first member thread to enable said latch member and first member to be moved longitudinally and Without rotation with respect to each other; and cam means carried by said second member and movable longitudinally of said latch member to positively shift said latch member laterally of said second member and out of threaded engagement with the thread of said first member.

'11. In apparatus of the character described: a first member; a second member, a spring-like expansible and contractible latch member carried by said second member and engageable with said first member to couple said first member to said second member; and cam means carried by said second member and movable longitudinally of said latch member to positively shift said latch member laterally of said second member and out of coupling engagement with said first member.

12. In apparatus of the character described: a first member; a second member; a spring-like expansible and contractible latch member carried by said second member and engageable with said first member to couple said first member to said second member; cam means carried by said second member and movable longitudinally of said latch member to positively shift said latch member laterally of said second member and out of coupling engagement with said first member; and a breakable connection releasably connecting said latch member to said second member.

13. In apparatus of the character described: a first member having an internal thread; a second member; an expansible and contractible latch member carried by said second member and having an external thread companion to said first member thread and engageable therewith; a retaining member movable longitudinally with respect to and engaging said latch member to hold its thread meshed with the internal thread of said first member; and means including a releasable connection securing said retaining member to said second member with said retaining member engaging said latch member, release of said connection enabling said retaining member to shift longitudinally out of engagement with said latch member to allow said latch member to shift laterally out of threaded engagement with said internal thread.

14. In apparatus of the character described: a first member having an internal thread; a second member; a sleeve having a plurality of externally threaded dogs meshable with said internal thread; a retaining member movable longitudinally with respect to and engaging said dogs to hold them meshed with said internal thread; and means including a readily disruptable connection securing said retaining member to said second member with said retaining member engaging said dogs, disruption of said connection enabling said retaining member to shift longitudinally out of engagement with said dogs to allow said dogs to retract out of threaded engagement with said internal thread.

15. In apparatus of the character described: a first member having an internal thread; a second member; a sleeve having a plurality of externally threaded dogs meshable with said internal thread; a retaining member movable longitudinally with respect to and engaging said dogs to hold them meshed with said internal thread; means including a readily disruptable connection securing said retaining member to said second member with said retaining member engaging said dogs, disruption of said connection enabling said retaining member to shift longitudinally out of engagement with said'dogs to allow said dogs to retract out of threaded engagement with said internal thread; and means on said retaining member engageable with said dogs, after disruption of said connection, to hold said dogs retracted and out of mesh with said internal thread.

16. In apparatus of the character described: a first member having an internal thread; a second member; a sleeve having a plurality of externally threaded inherently retractible spring-like dogs meshable with said internal thread; a retaining member movable longitudinally with respect to and engaging said dogs to hold them meshed with said internal thread; and means including a readily disruptable connection securing said retaining member to said second member with said retaining member engaging said dogs, disruption of said connection enabling said retaining member to shift longitudinally out of engagement with said dogs to allow said dogs to retract out of threaded engagement with said internal thread.

17. In apparatus of the character described: a first member having an internal thread; a second member; a

sleeve having a plurality of externally threaded inherently expansible spring-like dogs meshable with said internal thread; a retaining member movable longitudinally With respect to and engaging said dogs to hold them meshed with said internal thread; means including a readily disruptable connection securing said sleeve to said second member with said retaining member engaging said dogs, disruption of said connection enabling said retaining member to shift longitudinally out of engagement with said dogs to allow said dogs to retract out of threaded engagement with said internal thread; and means on said retaining member engageable with said dogs, after disruption of said connection, to retract said dogs out of mesh with said internal thread. p

18. In apparatus of the character described: a first member having an internal thread; a second member; a

sleeve having a plurality of externally threaded inherently retractible spring-like dogs meshable with said internal thread; a retaining member movable longitudinally with respect to and engaging said dogs to hold them meshed with said internal thread; means including a readily disruptable connection securing said retaining member to said second member with said retaining member engaging said dogs, disruption of said connection enabling said retaining member to shift longitudinally out of engagement with said dogs to allow said dogs to retract out of threaded engagement with said internal thread; and means providing a slidably splined connection between said sleeve and said second member.

19. In apparatus of the character described: a first member having an internal thread; a second member; a sleeve slidably splined to said second member and having a plurality of externally threaded inherently contractible spring-like dogs meshable with said internal thread; a retaining member within said sleeve movable longitudinally with respect to and engaging said dogs to hold them outward and meshed with said internal thread; means including a readily disruptable tension stud securing said retaining member to said second member with said retaining member engaging said dogs, disruption of said connection enabling said retaining member to shift longitudinally out of engagement with said dogs to allow said dogs to retract out of threaded engagement with said internal thread; and lock means on said retaining member engageable with said dogs, after disruption of said stud and longitudinal movement of said retaining member out of engagement with said dogs, to secure said dogs in their inherently retracted position out of mesh with said internal thread.

20. In apparatus of the character described: a first member having an internal thread; a second member; a springlike expansible and contractible latch member carried by said second member and having an external thread companion to said first member thread and engageable therewith, said second member and latch member being rotatable relative to said first member to thread said latch member along said first member thread; said latch member being movable laterally relatively with respect to said second member to an extent suificient to bring its external thread out of threaded engagement with said internal thread to enable said latch member and first member to be moved longitudinally and without rotation with respect to each other; and means engageable with said latch member for positively holding said latch member out of threaded engagement with said internal thread.

21. In apparatus of the character described: a first member having an internal thread; a second member; a spring-like expansible and contractible latch member carried by said second member and having an external thread companion to said first member thread and engageable therewith, said second member and latch member being rotatable relative to said first member to thread said latch member along said first member thread; said latch member being movable laterally relatively with respect to said second member to an extent sufficient to bring its external thread out of threaded engagement with said internal thread to enable said latch member and first member to be moved longitudinally and Without rotation with respect to each other; means for holding said latch member outwardly in threaded engagement with said internal thread; and means engageable with said latch member for positively holding said latch member out of threaded engagement with said internal thread.

22. In apparatus of the character described: a first member; a second member; expansible and contractible latch means carried by said second member and engageable with said first member to couple said first member to said second member; cam means carried by said second member and movable longitudinally of said latch means to positively shift said latch means laterally of said second member and out of coupling engagement with said first member; and a breakable connection releasably connecting one of. said means to said second member.

References Cited in the file of this patent UNITED STATES PATENTS 258,038 Evarts May 16, 1882 607,106 Winton July 12, 1898 614,944 Gaylor Nov. 29, 1898 951,593 Clarke Mar. 8, 1910 1,315,581 Scott Sept. 9, 1919 1,777,591 Thomas Oct. 7, 1930 1,856,917 Jordan et a1. May 3, 1932 1,898,261 Otis Feb. 21, 1933 2,128,102 Sherman Aug. 23, 1938 2,244,714 Livergood June 10, 1941 2,327,951 Zaleske Aug. 24, 1943 2,454,839 Ring Nov. 30, 1948 2,542,679 Kemnitz Feb. 20, 1951