US2948339A - Stop for well tubing - Google Patents

Description

1960 J. v. FREDD 2,948,339

STOP FOR WELL TUBING Filed Oct. 9, 1953 2 Sheets-Sheet 1 IN VEN TOR.

John V. Fre dd ATTORNEY Fig.2

r- 2,948,339 1C6 Patented Aug. 9, 1960' STOP FOR WELL TUBING John V. Fredd, Dallas, Tex., assignor to Otis Engineering Corporation, Dallas, Tex., a corporation of Texas Filed Oct. 9, 1953, Ser. No. 385,248

11 Claims. (Cl. 166-215) This invention relates to stop means for positioning well devices in predetermined positions in well tubing or casing.

One object of the invention is to provide a new and improved stop for positioning a well device in a predetermined position in well tubing or casing.

A particular object of the invention is to provide an improved. means for operating a well, wherein an openended tubing string in the well is provided with an obstruction to the passage of well tools downwardly out of the open end of said tubing but which permits substantially full flow of fluids in either direction through said tubing past the obstruction, said obstruction being removable when desired to provide full access to the well bore below the open end of the tubing.

Another object of the invention is to provide a new and improved stop for removably positioning a well de vice in a well tubing by means of a flexibleline. I V

Afurther object is to provide a tubing stop for openended well tubing to prevent passage of tools out of the open lower end of the tubing. I

Still another object is to provide a stop for use in a tubing string having spaced downwardly and upwardly facing stop shoulders which is locked in position by a release dog which engages the downwardly facing shoulder upon upward movement of the stop in the string to release stop dogs for movement to expanded positions to limit further downward movement of the stop by engaging the upwardly facing shoulder. V

A further object of the invention isto provide a re movable tubing stop for open-ended well tubing which may be positioned and removed from the well tubing by means of a flexible line.

A still further object is to provide a stop means for well devices which includes stop dogs held in retracted positions by a dead center mechanism which is released by a release dog upon upward movement of the stop means in the well tubing bringing the release dog into engagement with a downwardly facing shoulder or obstruction in said well tubing.

Still another object is to provide a removable tubing stop which does not appreciably restrict the flow of gas and liquids through the tubing.

Additional objects and advantages of the invention will be readily apparent from the reading of the following description of devices constructed in accordance with the invention, and reference to the accompanying drawings thereof, wherein: V

Figure l is a view, partly in elevation and partly in section, of a tubing stop being lowered through a well tubing string by a running tool; a

Figure 2 is a similar view of the tubing stop of Figure 1 showing it locked at a coupling recess of the tubing string;

Figure 3 is a side view of the stop dogs and plunger shown in Figures 1 and 2;

Figure 4 is a sectional view taken on the line 4-4 of Figure 3;

Figure 5 is a view, partly in elevation and partly in section, of a modified form of stop for well devices showing the stop as it appears while being lowered in a tubing' string;

Figure 6 is a similar view of the stop of Figure 5 showing it locked in position at a coupling recess of the tubing string;

Figure 7 is a horizontal sectional view taken on the line 77 of Figure 5;

Figures 8 and 9 are horizontal cross-sectional views.

taken on the lines 8-8 and 99, respectively, of Figure 6.

Referring now especially to Figures 1 and 2 of the drawings; thereference numeral 20 designates a tubing stop which includes a body 21 having a longitudinal slot or window 22 and a pair of downwardly and inwardly extending dog receiving slots 23 which communicate with the window of the body. 7

A plunger 24 is slidably disposed in the window and includes a dependent skirt 25 and a pair of upwardly extending spaced retainer flanges 26 and 27 which provide a slot 28 therebetween for receiving the lower reduced ends 29 of a pair of stop dogs 30. The stop dogs are provided with aligned arcuate recesses 31 in which is disposed a guide pin 32, whose function will be hereinafter described.

The plunger 24 is provided with an axial aperture 33, located between the retainer flanges, through which a spring guide rod 34 extends. The spring guide rod has an enlarged head 35 disposed between the retainer flanges which limits the downward movement of the spring guide rod with respect to the plunger. The head 35 also abuts the lower ends of the stop dogs 30. A spring 36 disposed in the window surrounding the spring guide rod has its opposite ends bearing against the plunger 24 and an internal stop shoulder 37 at the lower end of the body 21, whereby the spring biases the plunger and stop dogs and the spring guide rod upwardly. It will be evident that when the plunger moves upwardly, from the position shown in Figure 1 to the position shown in Figure 2, the stop dogs 30 will be moved upwardly and outwardly, their movement being directed by the slots 23 in which they are slidably disposed. The stop dogs move laterally outwardly with respect to each other during such movement, and the engagement of the guide pin 32 in the aligned arcuate recesses 31 insures that the movement of the stop dogs is simultaneous and equal.

The dogs 30 may be locked in the retracted position shown in Figure 1 by a lock rod 38 having an enlarged lock head or flange 39 on its lower end adapted to engage the upwardly facing stop shoulders 40 on the stop dogs 30 to prevent their upward movement by the spring 36, as will hereinafter be explained. The lock rod is slidable in the axial bore of a'fishing neck 41 rigidly secured to the upper end of the body 21 by a weld 42 or in any suitable manner. The upward movement of the lock rod 38 is limited by the lower end of the fishing neck which extends inwardly into the path of travel of the lock head 39.

The stop dogs 30 are notched to provide downwardly facing stop shoulders 43 for engaging an upwardly facing stop shoulder of the tubing string to anchor the tubing stop against downward movement in the tubing string 44 at a selected location therein when the stop dogs are released to move intoexpanded position. i

To assemble the tubing stop, the spring guide rodris inserted in the aperture 33 of the plunger 24. The spring 36 is then placed on the guide rod and this sub-assembly is inserted into the window 22 of the body. A screw driver or other rod-like tool is then inserted through one of the slots 23 to push the plunger downwardly to compress the spring 36. The projecting lower end of the spring guide rod is placed between the jaws of a vise and inserted intoits slot 23 and hooked over the guide pin' so that the guide pin is now also received in the arcuate recess 31 of this stop dog. The stop dogs are then allowed to drop down into the slot 28 of the plunger 24' to rest on the head 35 of the spring guide rod. The stop dogs are well lubricated prior to being assembled so that they slide freely in their slots. The tubing stop is then fully assembled and ready for attachment to a running tool.

The running tool 45 initially forms a part of the stop and includes a body 46 whose upper end is threaded so that it may be easily attached to a flexible line by any suitable fitting or coupling. The running tool body is provided with an elongate transverse slot 47, having a pair of plates 48 rotatably mounted therein on a pin 49 which extends transversely through the slot. A release dog 56 disposed between said plates has one end pivotably secured to the plates and is adapted to extend laterally outwardly of the slot beyond the body. A release spring 51 has its opposite ends rigidly secured to the pivot pin 49 and to the release dog and urges the dog outwardly in a clockwise direction (Figures 1 and 2) for a purpose which will be hereinafter explained.

A link 52 has its opposite ends pivotably secured to the plates 48 and to a plunger 53, and the end of the link secured to the plunger is disposed in a transverse slot 54 in the upper end of the plunger and pivots about a pin 55 which extends transversely through the slot 54. This plunger 53 is slidably inserted in a longitudinal cylindrical bore 56 of the body 46 which communicates at its upper end with the slot 47 in the body. The plunger has a dependent integral prong or rod 57 which extends axially through a skirt 58 threaded on the lower end of the body. The lower portion of the skirt is provided with radially spaced longitudinal slots 59 in which are disposed the upper portions of supporting dogs or hooks 60. Intermediate their ends, the hooks have inwardly extending lugs 61 which are pivotally connected by means of pivot pins 62 on a hook holder 63 slidably mounted in the bore of the skirt, the lugs extending into lateral slots 73 formed in the hook holder.

The hook holder has a reduced lower end portion 64 which extends downwardly beyond the lower end of the skirt 58 and the downwardly facing annular shoulder 65 formed at the upper end of the reduced portion of the hook holder abuts the upwardly facing shoulder of an internal flange 66 on the lower end of the skirt to limit downward movement of the hook holder in the skirt. Upward movement of the hook holder is restrained by a shear pin sleeve 67 whose lower end abuts the upper end of the hook holder. The shear pin sleeve is releasably connected to a hook expander 68 by a shear pin 69, and the upper end of the hook expander abuts the lower end 70 of the body 46 which thus prevents upward movement of the hook expander.

The hook expander has dependent expander members 71 which are disposed in registering slots 72, and 73 of the shear pin sleeve 67 and the hook holder 63, respectively. The lugs 61 of the hooks being also disposed in the slots 73, the expander member will contact the inwardly and upwardly inclined upper surfaces 61a of the hook lugs and cause the lower ends of the hooks to swing outwardly when the hook expander is moved downwardly by the spring 74 which biases the running tool plunger 53 upwardly and the hook expander downwardly.

The hook expander members 71 have downwardly and outwardly beveled cam surfaces 75 which contact the upper ends of the hooks 60 to hold the hooks in the position shown in Figure 1 until the pin 69 is sheared.

4 As the hook expander moves downwardly in the skirt 58 after the pin is sheared, the cam surfaces permit the upper ends of the hooks to move inwardly so the lower ends of the hooks can swing outwardly.

The hooks 60 have inwardly extending flanges or catches 76 which are adapted to engage the lower undercut shoulder of the flange 77 on the fishing neck 41, whereby the collar stop 20 is connected to and supported by the running tool.

In use, the tubing stop 20 having the running tool forming a part thereof is lowered into the tubing string;

44 by means of the running tool 45 whose threaded upper end is secured to the lower end of a flexible line running mechanism (not shown) by means of a suitable fitting. The various elements of the tubing stop and the running tool are in the positions shown in Figure l, with the running tool plunger 53 held in lowered position against the resistance of the spring 74 by the link 52 and plates '48, the planar edges 78 of the plates 48 abutting the inner wall 79 of the body 46 to limit counterclockwise rotation of the plate. The release dog '50 extends upwardly and outwardly from the slot47 of the running tool body, and its outer end is yieldingly biased outwardly by the spring 51 to contact the inner wall of the tubing as the tool is lowered therethrough. The release dog may be provided with a hardened metal insert or shoe 80 to protect the release dog against excessive wear.

The tubing stop is secured to the running tool by the hooks 60, and the plunger rod 57 holds the lock rod 38 in lowered position against the resistance of the spring 36 of the collar stop. The lock rod holds the stop dogs 30 in their retracted position.

As the running tool and the tubing stop are lowered through the tubing, the outer end of the release dog slides along the inner wall of the tubing string 44, pivoting in a counterclockwise direction against the resistance of the spring 51 upon meeting obstructions. The tubing string is composed of sections 81 connected by couplings or collars 82, and since adjacent ends of the tubing sections are spaced, an internal annular coupling recess 83 is formed at each coupling.

When the stop has been lowered to the particular location in the tubing string at which it is to be anchored or located, the running tool is raised until the release dog 50 enters into the first coupling recess 83 it encounters during such upward movement. Further lifting then causes the outer end of the release dog to contact the lower end of the upper tubing section 81 and,

as the lifting movement is continued, the release dog 50 causes the plates 48 to rotate in a clockwise manner. This causes the point of pivotal attachment of the link 52 to the plates 48 to move to the left of the pivot pin 49, or past dead center, so that the upward force of the spring 74 acting on the plunger 53 moves the plunger upwardly and rotates the plates 48 to the position shown in Figure 2, wherein further clockwise rotation of the plates 48 is prevented by the stop surface 84 of the running tool body and the release dog 50 is retracted into the slot 47 of said body.

The shoe 85, secured to the running tool body by a screw 86, abuts the tubing on the side opposite the release dog to prevent undue lateral displacement of the tool while the release dog is in engagement with the lower end of the tubing section and is being pivoted downwardly. In tubing of smaller diameter the shoe may be omitted.

. When the plunger 53 moves upwardly the lock rod 38 is freed to move upwardly, thus unlocking the dogs 30 for upward and outward movement. The spring 36 then moves the stop dogs 30 outwardly into engagement with the walls of the lower tubing section below the coupling recess into which the dog '50 had entered. The dogs are then still biased outwardly by the spring.

' The running tool is then raised until the stop dogs 30 enter into the coupling recess '83, the stop dogs sliding along the walls of the tubing until reaching this coupling.

the adjacent lower tubing section to prevent downward I movement of the collar stop andrunning tool in the tubing suing. The stop and running tool now act as a stop which may support any desired well device at such position in the tubing string. Of course, the runmng tool may be disconnected if desired to leave only the stop itself in place in the tubing.

When the stop dogs 30 prevent further downward movement, the lower end of the hook'holder 63 rests upon the upper end of the fishing neck 41 of the collar stop. Downward jarring imparted to the running tool through the flexible line running mechanism will now cause the pin 69 to shear, and thus free the hook expander for downward movement relative to the hook holder and the hooks. Further downward jars will positively move the hook expander 68 downwardly to cause said member to engage the inclined surfaces 61a on the hook lugs to pivot the hooks about their pivot pins and swing the hooks outwardly from supporting engagement with the flange on the fishing neck. I

' The spring 74 is under suflicient compression, after the running tool plunger has been moved upwardly, to move the hook expander 68 downwardly and cause the hook expander member to engage the inclined surfaces 61a on the hook lugs to hold the hooks in such disengaged position.

The running tool is then lifted out of the tubing string, leaving the tubing stop 20 in the tubing. The tubing stop will then prevent the passage of subsurface tools and instruments out of the lower open end of the tubing string and into the open casing. However, the tubing stop only partially blocks the longitudinal bore of the tubing string and thus does not substantially restrict flow of liquids or gas through the tubing string but does prevent passage of tools. Since the tubing stops offer little restriction to the flow of gases and liquids, it is not subjected to any considerable upward force and such upward force which may lift the tubing stop upwardly, to bring-the downwardly and outwardly inclined or beveled shoulders 81 of the stop dogs into contact with the lower end of the -upper tubing section, is not suflicient to cause the stop dogs to retract inwardly into the tubing stop. The tubing stop will thus be anchored in place at the desired location in the tubing string.

When it is desired to remove the collar stop from the tubing string, a suitable fishing tool is lowered by means of the flexible line lowering mechanism to engage the flange 77 on the fishing neck of the stop. An upward pull applied to the fishing neck will move the collar stop.

upwardly, and the beveled shoulders 87 on the upper ends of the stop dogs will cam the dogs to retracted position as they pass coupling recesses or other obstructions in the tubing string.

It will thus be seen that a new and improved removable tubing stop 20 has been provided which has a pair of retractable stop dogs 30 releasably held in retracted position by a look rod 38 and engageable with an internal upwardly facing stop shoulder of a tubing stn'ng when in expanded position to anchor the tubing stop inposition and against downward displacement-in the tubing string. It will also be seen that a running tool 45 has been provided for lowering and operating the collar stop, such running toolincluding a plunger 53 which releasably holds the lock rod 38 in locking position whereby the stop dogs are held retracted and a'r'elease mechanism which includes the release dog 50 engageable with a downwardly facing shoulder in the tubing string for releasing the plunger to permit the locking rod to move to unlocking position whereby the stop dogs are freed for expansion. It will also-be apparent that the collar stop may be positioned and removed by tools operated by means of a flexible line. It will also be seen that the" stop acts as a removable blocking means for" open end tubing strings to prevent passage of well tools outwardly from the open lower end of the tubing strings.

In Figures 5 and 6 is illustrated a modified form of the stop shown in Figures 1 and 2, which may be used to position well tools in a selected position in a well casing or in a tubing string. The stop includes an elongate body 91 which may be secured to a well tool by means of a sub 92 threaded in the upper end of the stop body. A pair of stop'dogs 93 are slidably mounted in a pair of upwardly and outwardly extending slots 94 of the-stop body. The lower inner ends of the stop dogs.

have downwardly extending L-shaped extensions 95 whose lower ends are adapted to engage camming shoulders 96 i formed at the upper enlarged end of aplunger 97, which also has formed thereon upwardly extending stop lugs 98 engageable with the extensions 95 to limit upward and outward movement of the stop dogs, and to retain said stop dogs within the body.

The lower portion of the plunger is reduced to provide 7 Tlhe stop dogs 93 are held in their retracted position v I by the lower end of a lock rod 103 which abuts stop shoulders 194 formed in the inner inclined backs of the stop dogs when the lock rod is positioned in the lowered locking :position shown in Figure 5. The lock rod is provided at its upper end with a pair of spaced upward extensions 1115 and 106 and toggle plates 107 are rotatably mounted on and between these extensions by a pivot pin 108. A release dog 109 has one end pivotably secured between the plates by a pin .110, and is biased outwardly by a spring 111 having one end secured to the pivot pin 108 and-its other end secured to the release dog. The stop body is provided with a transverse slot 112 which accommodates and provides access to the toggle plates and the release dog.

A link 113 hasits opposite ends pivotably secured by means of a pivot pin 114 to a bifurcated bushing 114a in the upper end of the bore of the stop body and between the plates 107 for rotation in a counterclockwise direction when the plates are in the position shown in Figure 5. The planar edges 116 of the toggle plates contact'the lower edge 117 of the transverse slot 112 of the stop body to limit such counterclockwise rotation'of the plates.

When the toggle plates 107 are rotated in a clockwise direction through a small angle by the release dog 109, the pivot pin forming the point of pivotal attachment'of the lower end of the link 113 to the plates is' displaced slightly to the right, past a deadcenter position, between the pivot pin 108 and the pin 114 forming the point of pivotal attachment of the upper end of the link to the bushing in the body, and at such time the plates 107 will be rotated to the position shown in Figure 6 by the spring 100. The link 113 is provided: with a, notch 119providingfor sufiicient rotation of the it will be noted that the 7 toggle plates to permit full upward retractive movement of the lock rod.

In use, the stop 90 is secured to the lower end of a well tool by means of the threaded upper end of its sub 92. The stop dogs 93 are held in their retracted positions by the lock rod 103 and the release dog l09 extends outwardly through the slot 112 to contact the inner wall of the tubing as the tool and the step are lowered downwardly through the string of tubing.

When the tool and stop are lowered to the desired position in the well, they are raised until the release dog enters into a coupling recess 83 and engages the lower end of the upper tubing section. Further upward movement now causes the release dog to rotate the toggle plates 107 in a clockwise manner until the link 113 is moved past the dead center position. The spring 100 then moves the plunger 97 upwardly and simultaneously moves the dogs 93 upwardly and outwardly to expanded positions. The lock rod 103, of course, has previously been moved upwardly by its engagement with the stop shoulders 104, and as the plates 107 were moved in a clockwise direction the release dog was retracted inwardly into the stop body, as shown in Figure 6.

The spring 100, acting upon the plunger, biases the stop dogs outwardly into yielding contact with the walls of the lower tubing section. The tool and stop are then raised until the stop dogs enter into the coupling recess and their stop shoulders 120 engage the upper end of the tubing section 81 therebelow to limit downward movement of the tool. The tool is thus held in a predetermined position in the tubing string against further downward movement.

When it is desired to remove the tool, it is raised upwardly and the beveled shoulders 121 cause the dogs to retract as they encounter obstructions, such as the lower ends of the tubing sections 81, in the upward movement.

It will now be seen that a new and improved stop and running tool has been provided which may be secured to Well tools and be used to position such tools in predetermined positions in a tubing string of a well. It will also be seen that the stop is provided with a pair of stop dogs 93 which are movable outwardly by the camming shoulders 96 of the plunger 97 biased upwardly by a spring 100, and that the plunger is held locked in lowered position by a dead center toggle mechanism which includes a lock rod 103. It will also be apparent that the dead center toggle mechanism includes a release dog 109 which releases the lock rod to permit the stop dogs to move to expanded position upon upward movement of the tool in the tubing string. It will be seen that the single spring 100 provides both the force which locks the dogs in retracted position and the force which moves them into expanded positions.

It will thus be apparent that several different forms of stops have been illustrated and described for positioning tubing stops and well tools in tubing strings at desired locations in the strings and for preventing well tools from passing downwardly through the tubing past said stops, while at the same time the stops permit substantial upward or downward flow of fluid through the tubing therepast.

Moreover, it will be seen that all of the stops are removable and may be lowered or removed by means of flexible lines. -It will also be seen that the stops are of relatively simple form, easy to manufacture and not susceptible to malfunctioning even under most unfavorable conditions.

The foregoing description of the inevntion is explanatory only, and changes in the details of the construction illustrated may be made by those skilled in the art, within the art, within the scope of the appended claims, without departing from the spirit of the invention.

ent is:

l. A stop for well devices adapted to be run into a well pipe by a detachable running tool, said stop including: a body having a central opening and a plurality of upwardly and outwardly extending slots communieating with said opening; a stop dog slidably mounted in each slot for movement between a retracted position wherein said dog does not impede movement of said body through a well flow conductor and an expanded position, said dog having an integral laterally projecting boss at its upper end and having a lower end portion extending into said opening; said stop dogs each having an upwardly facing lock shoulder formed thereon and movable into said body opening when the dog is moved downwardly to retracted position in its slot, said shoulder being adapted to be engaged by a member movable in the body opening from above by said running tool for positively holding said dog in such retracted positron; a plunger slidably disposed in said body and abutting the lower ends of said stop dogs; and resilient means in said opening biasing said plunger upwardly whereby said stop dogs are biased for upward and out ward movement in said slots toward expanded positions, said biasing means moving said stop dogs toward expand-ed position when said shoulders are not engaged by said holding means.

2. A stop for well devices including: a body having a central opening and a pair of upwardly and outwardly extending slots communicating with said opening; a stop dog slidably mounted in each slot and having a lower end portion extending into said central opening; said stop dogs each having an upwardly facing stop shoulder formed thereon and movable into said body opening when said dog is moved downwardly to retracted position in its slot, said shoulder being adapted to be engaged by a member inserted in the upper end of the opening of said body and movable downwardly therein into engagement with said shoulder for positively holding said dog in such retracted position; a plunger slidably disposed in said body and abutting the lower ends of said stop dogs; resilient means in said opening biasing said plunger upwardly whereby said stop dogs are biased for upward and outward movement in said slots toward expanded positions; and means engaging said dogs to permit only equal uniform movement of both stop dogs in said slots.

3. A stop for well devices including: a body having a central opening and a plurality of upwardly and outwardly extending slots communicating with said opening; a stop dog slidably mounted in each slot and having a lower end portion extending into said central opening; means engaging said dogs limiting upward outward movement of said dogs in said slots and providing for equal simultaneous movement of said dogs upwardly and outwardly in said slots; said stop dogs each having an upwardly facing stop shoulder formed thereon and movable into said body opening when the dog is moved downwardly toward retracted position in its slot; a plunger slidably disposed in said body and abutting the lower ends of said stop dogs; resilient means in said opening biasing said plunger upwardly whereby said stop dogs are biased for upward and outward movement in said slots toward expanded positions; and a rod in said body extending slidably into said central opening to engage said upwardly facing shoulders on said dogs and hold said stop dogs in retracted position against the force exerted by the resilient means.

4. A stop for well devices including: a body having a central opening and a plurality of upwardly and outwardly extending slots communicating with said opening; a stop dog slidably mounted in each slot and having a lower end portion extending into said central opening; said step dogs each having an upwardly facing e 9 shoulder'formed thereon and movableinto said body opening when the dog is moved downwardly'to retracted position in its slot; a plunger slidably disposed in said body and abutting the lower ends of said stop' dogs; resilient means on said body biasing saidiplun'ger upwardly whereby said stop dogs are biased for upward and outward'movement in said slots toward expanded positions; means engaging said stop dogs for limiting up ward and outward movement of said stop dogs in said slots and providing for equal simultaneous movement of said dogs in said slots; a rod in said body extending slidably into said opening to engage said upwardly facing shoulders of said stop dogs when the said shoulders are disposed in the opening in the body and hold said stop dogs in retracted position; and release means for releasably' holding said rod in stop dog locking position, ;said release means having an outwardly extending release-dog 'engageable with a well tubing upon upward movement of said tubular stop in the well tubing for actuating said'release means and freeing said stop dogs for movement to expanded position.

5. A stop for well devices including: a body having a central opening and 'a' plurality of upwardly and outwardly extending slots communicating withv Said opening; a stop dog slidably mounted in each slot and having a lower end portion extending into said central opening; said stop dogs each having an upwardly facing lock shoulder formed thereon and movable in said body opening when said dog is moved downwardly to retracted position in its slot; a plunger slidably disposed in said body and abutting the lower ends of said stop dogs; resilient means in said central opening biasing said plunger upwardly whereby said stop dogs are biased for upward and outward movement in said slots toward expanded positions; means engaging the lower end portions of said stop dogs for limiting upward outward movement of said stop dogs in said slots; a rod on said body extending slidably into said central opening to engage said upwardly facing shoulders on said stop dogs and hold sai-d stop dogs in retracted position; a fishing neck secured to said body and having a bore therein communicating with the opening of the body; a running tool engageable with said fishing neck and having holding means extending downwardly in said bore of said fishing neck to engage said rod to prevent upward movement thereof; and release means on said running tool for releasing said holding means to permit upward movement thereof.

6. A stop for well devices including: a body having a central opening and a pair of upwardly and outwardly extending slots communicating with said opening; a stop dog slidably mounted in each slot and having a lower end portion extending into said central opening; said stop dogs each having an upwardly facing lock shoulder formed thereon and movable into said body opening -when the dog is moved downwardly toward retracted position in its slot; a plunger slidably disposed in said body and abutting the lower ends of said stop dogs; re- :silient means on said body biasing said plunger up- --wardly whereby said stop dogs are biased for upward .--and outward movement in said slots toward expanded positions; means engaging the lower portions of said .dogs for limiting upward and outward movement of -said dogs in said slots and for causing simultaneous Y movement of said dogs in said slots; a rod on said body extending slidably into said central opening to engage the upwardly facing lock shoulders on said 'stop dogs and hold said stop dogs in retracted position; a tubular fishing neck secured to said body and eugageable by a running tool; a running tool engageable with said fish- '"ing neck and having holding means extending downwardly in the bore of said tubular fishing. neck to engage said rod to prevent upward movement thereof;

release means on said running tool for releasing said r 10 holding means to permit upward movement thereof; and releasable means on said running tool for attaching said running tool to said fishing neck, said releasable means being actuated by downward jars after said stop dogs have been moved to expanded positions to limit downward movement of said body. 7. A stop for well tubing including: a body having a plurality of windows; a stop dog movable through each window to expanded position; central control means extending longitudinally of said body and having means eugageable with said stop dogs for moving said stop dogs to expanded positions upon longitudinal movement of said control means in said body; means biasing said control means for longitudinal movement in said body; and means connected with said body and engageable with said stop dogs for holding said stop dogs in retracted position and thus preventing longitudinal movement of said control means in said body, said last-mentioned means having a portion engageable with said tubing and actuatable to permit said longitudinal move,

ment of said control means, said stop dogs engaging an upwardly. facing shoulder of said tubing when in ex-' panded position to prevent further downward movement of the stop in said tubing.

8. A stop for well tubing including: a body having a plurality of lateral openings; stop means movable through each lateral opening to expanded position; said stop means having upwardly facing lock shoulders formed thereon; control means movable in said body having means engageable with said stop means for moving said stop means to expanded position; means biasing said control means for movement in the body to expand said stop means; and means connected with said body and said upwardly facing lock shoulders of said stop means for preventing expanding movement of said control means in said body, said last named means being engageable with a well tubing and actuatable to permit movement of said control means, said stop means being engageable with a stop shoulder of said tubing when in expanded position to limit downward movement of said stop in said tubing.

9. A stop for well devices including: a body having a central opening and a plurality of upwardly and outwardly extending slots communicating with said opening; a stop dog slidably mounted in each slot and having a lower end portion extending into said central opening; a plunger slidably disposed in said body and abutting the lower ends of said stop dogs in said opening; resilient means in said opening biasing said plunger upwardly whereby said stop dogs are biased for upward and outward movement in said slots toward expanded position; each of said stop dogs having an upwardly facing stop shoulder thereon positioned to be exposed in said central opening when said stop dog is in retracted position; a rod on said body extending slidably into said central opening to engage said upwardly facing stop shoulders of said stop dogs and hold said stop dogs in retracted position; a running tool connected with said body and having holding means extending downwardly in the opening of the body to engage said rod to prevent upward movement thereof when said running tool is engaged with said body; and release means on said running tool for releasing said holding means to permit upward movement thereof to permit said rod to move upwardly to free said stop dogs for movement I toward projecting position.

wardly'whereby said stop dogs are biased for upward and outward movement in said slots toward expanded position; each of said stop dogs having an upwardly facing stop shoulder thereon positioned to be exposed in said central opening when said stop dog is in retracted position; a rod on said body extending slidably into said control opening to engage said upwardly facing stop shoulders of said stop dogs and hold said stop dogs in retracted position; a running tool releasably connected with said body and having holding means extending downwardly in the central opening of the body to engage said rod to prevent upward movement thereof when said r-unning tool is engaged with said body; and release means on said running tool for releasing said holding means to permit upward movement thereof to permit said rod to move upwardly to free said stop dogs for movement toward projecting position, said running tool being rel easable from connection with said body.

11. A stop for well devices comprising: a body adapted to be lowered into a well tubing having a stop shoulder therein; said body having a longitudinal bore formed therein and open at its upper end; a stop dog mounted on said body for movement laterally of said body between retracted position wherein said dog does not enwhen the dog is in retracted position; means movable in the bore of the body engageable with said shoulders for releasably holding said dogs retracted; and resilient means biasing said dog toward projecting position.

References Cited in the file of this patent UNITED STATES PATENTS 1,189,516 Whitney July 4, 1916 1,233,888 Leonard July 17, 1917 1,835,377 Clark et all Dec. 8, 1931 1,996,264 Turner Apr. 2, 193-5 1,229,581 McLaughlin Jan. 21, 1941 2,251,125 Gardner July 25, 1941 2,380,669 Mowrey July 31, 1945 2,401,119 Taylor May 28, 1946 2,539,353 Minyard Jan. 23, 1951 2,644,527 Baker July 7, 1953 2,816,613

Minter et al. Dec. "17, 1957

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